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lmdb/libraries/liblmdb/mdb.c

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/** @file mdb.c
* @brief Lightning memory-mapped database library
*
* A Btree-based database management library modeled loosely on the
* BerkeleyDB API, but much simplified.
*/
/*
* Copyright 2011-2020 Howard Chu, Symas Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*
* This code is derived from btree.c written by Martin Hedenfalk.
*
* Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#if defined(MDB_VL32) || defined(__WIN64__)
#define _FILE_OFFSET_BITS 64
#endif
#ifdef _WIN32
#include <malloc.h>
#include <windows.h>
#include <wchar.h> /* get wcscpy() */
/* We use native NT APIs to setup the memory map, so that we can
* let the DB file grow incrementally instead of always preallocating
* the full size. These APIs are defined in <wdm.h> and <ntifs.h>
* but those headers are meant for driver-level development and
* conflict with the regular user-level headers, so we explicitly
* declare them here. We get pointers to these functions from
* NTDLL.DLL at runtime, to avoid buildtime dependencies on any
* NTDLL import libraries.
*/
typedef NTSTATUS (WINAPI NtCreateSectionFunc)
(OUT PHANDLE sh, IN ACCESS_MASK acc,
IN void * oa OPTIONAL,
IN PLARGE_INTEGER ms OPTIONAL,
IN ULONG pp, IN ULONG aa, IN HANDLE fh OPTIONAL);
static NtCreateSectionFunc *NtCreateSection;
typedef enum _SECTION_INHERIT {
ViewShare = 1,
ViewUnmap = 2
} SECTION_INHERIT;
typedef NTSTATUS (WINAPI NtMapViewOfSectionFunc)
(IN PHANDLE sh, IN HANDLE ph,
IN OUT PVOID *addr, IN ULONG_PTR zbits,
IN SIZE_T cs, IN OUT PLARGE_INTEGER off OPTIONAL,
IN OUT PSIZE_T vs, IN SECTION_INHERIT ih,
IN ULONG at, IN ULONG pp);
static NtMapViewOfSectionFunc *NtMapViewOfSection;
typedef NTSTATUS (WINAPI NtCloseFunc)(HANDLE h);
static NtCloseFunc *NtClose;
/** getpid() returns int; MinGW defines pid_t but MinGW64 typedefs it
* as int64 which is wrong. MSVC doesn't define it at all, so just
* don't use it.
*/
#define MDB_PID_T int
#define MDB_THR_T DWORD
#include <sys/types.h>
#include <sys/stat.h>
#ifdef __GNUC__
# include <sys/param.h>
#else
# define LITTLE_ENDIAN 1234
# define BIG_ENDIAN 4321
# define BYTE_ORDER LITTLE_ENDIAN
# ifndef SSIZE_MAX
# define SSIZE_MAX INT_MAX
# endif
#endif
#define MDB_OFF_T int64_t
#else
#include <sys/types.h>
#include <sys/stat.h>
#define MDB_PID_T pid_t
#define MDB_THR_T pthread_t
#include <sys/param.h>
#include <sys/uio.h>
#include <sys/mman.h>
#ifdef HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#include <fcntl.h>
#define MDB_OFF_T off_t
#endif
#if defined(__mips) && defined(__linux)
/* MIPS has cache coherency issues, requires explicit cache control */
#include <asm/cachectl.h>
extern int cacheflush(char *addr, int nbytes, int cache);
#define CACHEFLUSH(addr, bytes, cache) cacheflush(addr, bytes, cache)
#else
#define CACHEFLUSH(addr, bytes, cache)
#endif
#if defined(__linux) && !defined(MDB_FDATASYNC_WORKS)
/** fdatasync is broken on ext3/ext4fs on older kernels, see
* description in #mdb_env_open2 comments. You can safely
* define MDB_FDATASYNC_WORKS if this code will only be run
* on kernels 3.6 and newer.
*/
#define BROKEN_FDATASYNC
#endif
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#ifdef _MSC_VER
#include <io.h>
typedef SSIZE_T ssize_t;
#else
#include <unistd.h>
#endif
#if defined(__sun) || defined(__ANDROID__)
/* Most platforms have posix_memalign, older may only have memalign */
#define HAVE_MEMALIGN 1
#include <malloc.h>
/* On Solaris, we need the POSIX sigwait function */
#if defined (__sun)
# define _POSIX_PTHREAD_SEMANTICS 1
#endif
#endif
#if !(defined(BYTE_ORDER) || defined(__BYTE_ORDER))
#include <netinet/in.h>
#include <resolv.h> /* defines BYTE_ORDER on HPUX and Solaris */
#endif
#if defined(__FreeBSD__) && defined(__FreeBSD_version) && __FreeBSD_version >= 1100110
# define MDB_USE_POSIX_MUTEX 1
# define MDB_USE_ROBUST 1
#elif defined(__APPLE__) || defined (BSD) || defined(__FreeBSD_kernel__)
# if !(defined(MDB_USE_POSIX_MUTEX) || defined(MDB_USE_POSIX_SEM))
# define MDB_USE_SYSV_SEM 1
# endif
# define MDB_FDATASYNC fsync
#elif defined(__ANDROID__)
# define MDB_FDATASYNC fsync
#endif
#ifndef _WIN32
#include <pthread.h>
#include <signal.h>
#ifdef MDB_USE_POSIX_SEM
# define MDB_USE_HASH 1
#include <semaphore.h>
#elif defined(MDB_USE_SYSV_SEM)
#include <sys/ipc.h>
#include <sys/sem.h>
#ifdef _SEM_SEMUN_UNDEFINED
union semun {
int val;
struct semid_ds *buf;
unsigned short *array;
};
#endif /* _SEM_SEMUN_UNDEFINED */
#else
#define MDB_USE_POSIX_MUTEX 1
#endif /* MDB_USE_POSIX_SEM */
#endif /* !_WIN32 */
#if defined(_WIN32) + defined(MDB_USE_POSIX_SEM) + defined(MDB_USE_SYSV_SEM) \
+ defined(MDB_USE_POSIX_MUTEX) != 1
# error "Ambiguous shared-lock implementation"
#endif
#ifdef USE_VALGRIND
#include <valgrind/memcheck.h>
#define VGMEMP_CREATE(h,r,z) VALGRIND_CREATE_MEMPOOL(h,r,z)
#define VGMEMP_ALLOC(h,a,s) VALGRIND_MEMPOOL_ALLOC(h,a,s)
#define VGMEMP_FREE(h,a) VALGRIND_MEMPOOL_FREE(h,a)
#define VGMEMP_DESTROY(h) VALGRIND_DESTROY_MEMPOOL(h)
#define VGMEMP_DEFINED(a,s) VALGRIND_MAKE_MEM_DEFINED(a,s)
#else
#define VGMEMP_CREATE(h,r,z)
#define VGMEMP_ALLOC(h,a,s)
#define VGMEMP_FREE(h,a)
#define VGMEMP_DESTROY(h)
#define VGMEMP_DEFINED(a,s)
#endif
#ifndef BYTE_ORDER
# if (defined(_LITTLE_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(_LITTLE_ENDIAN) && defined(_BIG_ENDIAN))
/* Solaris just defines one or the other */
# define LITTLE_ENDIAN 1234
# define BIG_ENDIAN 4321
# ifdef _LITTLE_ENDIAN
# define BYTE_ORDER LITTLE_ENDIAN
# else
# define BYTE_ORDER BIG_ENDIAN
# endif
# else
# define BYTE_ORDER __BYTE_ORDER
# endif
#endif
#ifndef LITTLE_ENDIAN
#define LITTLE_ENDIAN __LITTLE_ENDIAN
#endif
#ifndef BIG_ENDIAN
#define BIG_ENDIAN __BIG_ENDIAN
#endif
#if defined(__i386) || defined(__x86_64) || defined(_M_IX86)
#define MISALIGNED_OK 1
#endif
#include "lmdb.h"
#include "midl.h"
#if (BYTE_ORDER == LITTLE_ENDIAN) == (BYTE_ORDER == BIG_ENDIAN)
# error "Unknown or unsupported endianness (BYTE_ORDER)"
#elif (-6 & 5) || CHAR_BIT!=8 || UINT_MAX!=0xffffffff || MDB_SIZE_MAX%UINT_MAX
# error "Two's complement, reasonably sized integer types, please"
#endif
#ifdef __GNUC__
/** Put infrequently used env functions in separate section */
# ifdef __APPLE__
# define ESECT __attribute__ ((section("__TEXT,text_env")))
# else
# define ESECT __attribute__ ((section("text_env")))
# endif
#else
#define ESECT
#endif
#ifdef _WIN32
#define CALL_CONV WINAPI
#else
#define CALL_CONV
#endif
/** @defgroup internal LMDB Internals
* @{
*/
/** @defgroup compat Compatibility Macros
* A bunch of macros to minimize the amount of platform-specific ifdefs
* needed throughout the rest of the code. When the features this library
* needs are similar enough to POSIX to be hidden in a one-or-two line
* replacement, this macro approach is used.
* @{
*/
/** Features under development */
#ifndef MDB_DEVEL
#define MDB_DEVEL 0
#endif
/** Wrapper around __func__, which is a C99 feature */
#if __STDC_VERSION__ >= 199901L
# define mdb_func_ __func__
#elif __GNUC__ >= 2 || _MSC_VER >= 1300
# define mdb_func_ __FUNCTION__
#else
/* If a debug message says <mdb_unknown>(), update the #if statements above */
# define mdb_func_ "<mdb_unknown>"
#endif
/* Internal error codes, not exposed outside liblmdb */
#define MDB_NO_ROOT (MDB_LAST_ERRCODE + 10)
#ifdef _WIN32
#define MDB_OWNERDEAD ((int) WAIT_ABANDONED)
#elif defined MDB_USE_SYSV_SEM
#define MDB_OWNERDEAD (MDB_LAST_ERRCODE + 11)
#elif defined(MDB_USE_POSIX_MUTEX) && defined(EOWNERDEAD)
#define MDB_OWNERDEAD EOWNERDEAD /**< #LOCK_MUTEX0() result if dead owner */
#endif
#ifdef __GLIBC__
#define GLIBC_VER ((__GLIBC__ << 16 )| __GLIBC_MINOR__)
#endif
/** Some platforms define the EOWNERDEAD error code
* even though they don't support Robust Mutexes.
* Compile with -DMDB_USE_ROBUST=0, or use some other
* mechanism like -DMDB_USE_SYSV_SEM instead of
* -DMDB_USE_POSIX_MUTEX. (SysV semaphores are
* also Robust, but some systems don't support them
* either.)
*/
#ifndef MDB_USE_ROBUST
/* Android currently lacks Robust Mutex support. So does glibc < 2.4. */
# if defined(MDB_USE_POSIX_MUTEX) && (defined(__ANDROID__) || \
(defined(__GLIBC__) && GLIBC_VER < 0x020004))
# define MDB_USE_ROBUST 0
# else
# define MDB_USE_ROBUST 1
# endif
#endif /* !MDB_USE_ROBUST */
#if defined(MDB_USE_POSIX_MUTEX) && (MDB_USE_ROBUST)
/* glibc < 2.12 only provided _np API */
# if (defined(__GLIBC__) && GLIBC_VER < 0x02000c) || \
(defined(PTHREAD_MUTEX_ROBUST_NP) && !defined(PTHREAD_MUTEX_ROBUST))
# define PTHREAD_MUTEX_ROBUST PTHREAD_MUTEX_ROBUST_NP
# define pthread_mutexattr_setrobust(attr, flag) pthread_mutexattr_setrobust_np(attr, flag)
# define pthread_mutex_consistent(mutex) pthread_mutex_consistent_np(mutex)
# endif
#endif /* MDB_USE_POSIX_MUTEX && MDB_USE_ROBUST */
#if defined(MDB_OWNERDEAD) && (MDB_USE_ROBUST)
#define MDB_ROBUST_SUPPORTED 1
#endif
#ifdef _WIN32
#define MDB_USE_HASH 1
#define MDB_PIDLOCK 0
#define THREAD_RET DWORD
#define pthread_t HANDLE
#define pthread_mutex_t HANDLE
#define pthread_cond_t HANDLE
typedef HANDLE mdb_mutex_t, mdb_mutexref_t;
#define pthread_key_t DWORD
#define pthread_self() GetCurrentThreadId()
#define pthread_key_create(x,y) \
((*(x) = TlsAlloc()) == TLS_OUT_OF_INDEXES ? ErrCode() : 0)
#define pthread_key_delete(x) TlsFree(x)
#define pthread_getspecific(x) TlsGetValue(x)
#define pthread_setspecific(x,y) (TlsSetValue(x,y) ? 0 : ErrCode())
#define pthread_mutex_unlock(x) ReleaseMutex(*x)
#define pthread_mutex_lock(x) WaitForSingleObject(*x, INFINITE)
#define pthread_cond_signal(x) SetEvent(*x)
#define pthread_cond_wait(cond,mutex) do{SignalObjectAndWait(*mutex, *cond, INFINITE, FALSE); WaitForSingleObject(*mutex, INFINITE);}while(0)
#define THREAD_CREATE(thr,start,arg) \
(((thr) = CreateThread(NULL, 0, start, arg, 0, NULL)) ? 0 : ErrCode())
#define THREAD_FINISH(thr) \
(WaitForSingleObject(thr, INFINITE) ? ErrCode() : 0)
#define LOCK_MUTEX0(mutex) WaitForSingleObject(mutex, INFINITE)
#define UNLOCK_MUTEX(mutex) ReleaseMutex(mutex)
#define mdb_mutex_consistent(mutex) 0
#define getpid() GetCurrentProcessId()
#define MDB_FDATASYNC(fd) (!FlushFileBuffers(fd))
#define MDB_MSYNC(addr,len,flags) (!FlushViewOfFile(addr,len))
#define ErrCode() GetLastError()
#define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
#define close(fd) (CloseHandle(fd) ? 0 : -1)
#define munmap(ptr,len) UnmapViewOfFile(ptr)
#ifdef PROCESS_QUERY_LIMITED_INFORMATION
#define MDB_PROCESS_QUERY_LIMITED_INFORMATION PROCESS_QUERY_LIMITED_INFORMATION
#else
#define MDB_PROCESS_QUERY_LIMITED_INFORMATION 0x1000
#endif
#else
#define THREAD_RET void *
#define THREAD_CREATE(thr,start,arg) pthread_create(&thr,NULL,start,arg)
#define THREAD_FINISH(thr) pthread_join(thr,NULL)
/** For MDB_LOCK_FORMAT: True if readers take a pid lock in the lockfile */
#define MDB_PIDLOCK 1
#ifdef MDB_USE_POSIX_SEM
typedef sem_t *mdb_mutex_t, *mdb_mutexref_t;
#define LOCK_MUTEX0(mutex) mdb_sem_wait(mutex)
#define UNLOCK_MUTEX(mutex) sem_post(mutex)
static int
mdb_sem_wait(sem_t *sem)
{
int rc;
while ((rc = sem_wait(sem)) && (rc = errno) == EINTR) ;
return rc;
}
#elif defined MDB_USE_SYSV_SEM
typedef struct mdb_mutex {
int semid;
int semnum;
int *locked;
} mdb_mutex_t[1], *mdb_mutexref_t;
#define LOCK_MUTEX0(mutex) mdb_sem_wait(mutex)
#define UNLOCK_MUTEX(mutex) do { \
struct sembuf sb = { 0, 1, SEM_UNDO }; \
sb.sem_num = (mutex)->semnum; \
*(mutex)->locked = 0; \
semop((mutex)->semid, &sb, 1); \
} while(0)
static int
mdb_sem_wait(mdb_mutexref_t sem)
{
int rc, *locked = sem->locked;
struct sembuf sb = { 0, -1, SEM_UNDO };
sb.sem_num = sem->semnum;
do {
if (!semop(sem->semid, &sb, 1)) {
rc = *locked ? MDB_OWNERDEAD : MDB_SUCCESS;
*locked = 1;
break;
}
} while ((rc = errno) == EINTR);
return rc;
}
#define mdb_mutex_consistent(mutex) 0
#else /* MDB_USE_POSIX_MUTEX: */
/** Shared mutex/semaphore as the original is stored.
*
* Not for copies. Instead it can be assigned to an #mdb_mutexref_t.
* When mdb_mutexref_t is a pointer and mdb_mutex_t is not, then it
* is array[size 1] so it can be assigned to the pointer.
*/
typedef pthread_mutex_t mdb_mutex_t[1];
/** Reference to an #mdb_mutex_t */
typedef pthread_mutex_t *mdb_mutexref_t;
/** Lock the reader or writer mutex.
* Returns 0 or a code to give #mdb_mutex_failed(), as in #LOCK_MUTEX().
*/
#define LOCK_MUTEX0(mutex) pthread_mutex_lock(mutex)
/** Unlock the reader or writer mutex.
*/
#define UNLOCK_MUTEX(mutex) pthread_mutex_unlock(mutex)
/** Mark mutex-protected data as repaired, after death of previous owner.
*/
#define mdb_mutex_consistent(mutex) pthread_mutex_consistent(mutex)
#endif /* MDB_USE_POSIX_SEM || MDB_USE_SYSV_SEM */
/** Get the error code for the last failed system function.
*/
#define ErrCode() errno
/** An abstraction for a file handle.
* On POSIX systems file handles are small integers. On Windows
* they're opaque pointers.
*/
#define HANDLE int
/** A value for an invalid file handle.
* Mainly used to initialize file variables and signify that they are
* unused.
*/
#define INVALID_HANDLE_VALUE (-1)
/** Get the size of a memory page for the system.
* This is the basic size that the platform's memory manager uses, and is
* fundamental to the use of memory-mapped files.
*/
#define GET_PAGESIZE(x) ((x) = sysconf(_SC_PAGE_SIZE))
#endif
#define Z MDB_FMT_Z /**< printf/scanf format modifier for size_t */
#define Yu MDB_PRIy(u) /**< printf format for #mdb_size_t */
#define Yd MDB_PRIy(d) /**< printf format for 'signed #mdb_size_t' */
#ifdef MDB_USE_SYSV_SEM
#define MNAME_LEN (sizeof(int))
#else
#define MNAME_LEN (sizeof(pthread_mutex_t))
#endif
/** Initial part of #MDB_env.%me_mutexname[].
* Changes to this code must be reflected in #MDB_LOCK_FORMAT.
*/
#ifdef _WIN32
#define MUTEXNAME_PREFIX "Global\\MDB"
#elif defined MDB_USE_POSIX_SEM
#define MUTEXNAME_PREFIX "/MDB"
#endif
/** @} */
#ifdef MDB_ROBUST_SUPPORTED
/** Lock mutex, handle any error, set rc = result.
* Return 0 on success, nonzero (not rc) on error.
*/
#define LOCK_MUTEX(rc, env, mutex) \
(((rc) = LOCK_MUTEX0(mutex)) && \
((rc) = mdb_mutex_failed(env, mutex, rc)))
static int mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc);
#else
#define LOCK_MUTEX(rc, env, mutex) ((rc) = LOCK_MUTEX0(mutex))
#define mdb_mutex_failed(env, mutex, rc) (rc)
#endif
#ifndef _WIN32
/** A flag for opening a file and requesting synchronous data writes.
* This is only used when writing a meta page. It's not strictly needed;
* we could just do a normal write and then immediately perform a flush.
* But if this flag is available it saves us an extra system call.
*
* @note If O_DSYNC is undefined but exists in /usr/include,
* preferably set some compiler flag to get the definition.
*/
#ifndef MDB_DSYNC
# ifdef O_DSYNC
# define MDB_DSYNC O_DSYNC
# else
# define MDB_DSYNC O_SYNC
# endif
#endif
#endif
/** Function for flushing the data of a file. Define this to fsync
* if fdatasync() is not supported.
*/
#ifndef MDB_FDATASYNC
# define MDB_FDATASYNC fdatasync
#endif
#ifndef MDB_MSYNC
# define MDB_MSYNC(addr,len,flags) msync(addr,len,flags)
#endif
#ifndef MS_SYNC
#define MS_SYNC 1
#endif
#ifndef MS_ASYNC
#define MS_ASYNC 0
#endif
/** A page number in the database.
* Note that 64 bit page numbers are overkill, since pages themselves
* already represent 12-13 bits of addressable memory, and the OS will
* always limit applications to a maximum of 63 bits of address space.
*
* @note In the #MDB_node structure, we only store 48 bits of this value,
* which thus limits us to only 60 bits of addressable data.
*/
typedef MDB_ID pgno_t;
/** A transaction ID.
* See struct MDB_txn.mt_txnid for details.
*/
typedef MDB_ID txnid_t;
/** @defgroup debug Debug Macros
* @{
*/
#ifndef MDB_DEBUG
/** Enable debug output. Needs variable argument macros (a C99 feature).
* Set this to 1 for copious tracing. Set to 2 to add dumps of all IDLs
* read from and written to the database (used for free space management).
*/
#define MDB_DEBUG 0
#endif
#if MDB_DEBUG
static int mdb_debug;
static txnid_t mdb_debug_start;
/** Print a debug message with printf formatting.
* Requires double parenthesis around 2 or more args.
*/
# define DPRINTF(args) ((void) ((mdb_debug) && DPRINTF0 args))
# define DPRINTF0(fmt, ...) \
fprintf(stderr, "%s:%d " fmt "\n", mdb_func_, __LINE__, __VA_ARGS__)
#else
# define DPRINTF(args) ((void) 0)
#endif
/** Print a debug string.
* The string is printed literally, with no format processing.
*/
#define DPUTS(arg) DPRINTF(("%s", arg))
/** Debuging output value of a cursor DBI: Negative in a sub-cursor. */
#define DDBI(mc) \
(((mc)->mc_flags & C_SUB) ? -(int)(mc)->mc_dbi : (int)(mc)->mc_dbi)
/** @} */
/** @brief The maximum size of a database page.
*
* It is 32k or 64k, since value-PAGEBASE must fit in
* #MDB_page.%mp_upper.
*
* LMDB will use database pages < OS pages if needed.
* That causes more I/O in write transactions: The OS must
* know (read) the whole page before writing a partial page.
*
* Note that we don't currently support Huge pages. On Linux,
* regular data files cannot use Huge pages, and in general
* Huge pages aren't actually pageable. We rely on the OS
* demand-pager to read our data and page it out when memory
* pressure from other processes is high. So until OSs have
* actual paging support for Huge pages, they're not viable.
*/
#define MAX_PAGESIZE (PAGEBASE ? 0x10000 : 0x8000)
/** The minimum number of keys required in a database page.
* Setting this to a larger value will place a smaller bound on the
* maximum size of a data item. Data items larger than this size will
* be pushed into overflow pages instead of being stored directly in
* the B-tree node. This value used to default to 4. With a page size
* of 4096 bytes that meant that any item larger than 1024 bytes would
* go into an overflow page. That also meant that on average 2-3KB of
* each overflow page was wasted space. The value cannot be lower than
* 2 because then there would no longer be a tree structure. With this
* value, items larger than 2KB will go into overflow pages, and on
* average only 1KB will be wasted.
*/
#define MDB_MINKEYS 2
/** A stamp that identifies a file as an LMDB file.
* There's nothing special about this value other than that it is easily
* recognizable, and it will reflect any byte order mismatches.
*/
#define MDB_MAGIC 0xBEEFC0DE
/** The version number for a database's datafile format. */
#define MDB_DATA_VERSION ((MDB_DEVEL) ? 999 : 2)
/** The version number for a database's lockfile format. */
#define MDB_LOCK_VERSION ((MDB_DEVEL) ? 999 : 2)
/** Number of bits representing #MDB_LOCK_VERSION in #MDB_LOCK_FORMAT.
* The remaining bits must leave room for #MDB_lock_desc.
*/
#define MDB_LOCK_VERSION_BITS 12
/** @brief The max size of a key we can write, or 0 for computed max.
*
* This macro should normally be left alone or set to 0.
* Note that a database with big keys or dupsort data cannot be
* reliably modified by a liblmdb which uses a smaller max.
* The default is 511 for backwards compat, or 0 when #MDB_DEVEL.
*
* Other values are allowed, for backwards compat. However:
* A value bigger than the computed max can break if you do not
* know what you are doing, and liblmdb <= 0.9.10 can break when
* modifying a DB with keys/dupsort data bigger than its max.
*
* Data items in an #MDB_DUPSORT database are also limited to
* this size, since they're actually keys of a sub-DB. Keys and
* #MDB_DUPSORT data items must fit on a node in a regular page.
*/
#ifndef MDB_MAXKEYSIZE
#define MDB_MAXKEYSIZE ((MDB_DEVEL) ? 0 : 511)
#endif
/** The maximum size of a key we can write to the environment. */
#if MDB_MAXKEYSIZE
#define ENV_MAXKEY(env) (MDB_MAXKEYSIZE)
#else
#define ENV_MAXKEY(env) ((env)->me_maxkey)
#endif
/** @brief The maximum size of a data item.
*
* We only store a 32 bit value for node sizes.
*/
#define MAXDATASIZE 0xffffffffUL
#if MDB_DEBUG
/** Key size which fits in a #DKBUF.
* @ingroup debug
*/
#define DKBUF_MAXKEYSIZE ((MDB_MAXKEYSIZE) > 0 ? (MDB_MAXKEYSIZE) : 511)
/** A key buffer.
* @ingroup debug
* This is used for printing a hex dump of a key's contents.
*/
#define DKBUF char kbuf[DKBUF_MAXKEYSIZE*2+1]
/** Display a key in hex.
* @ingroup debug
* Invoke a function to display a key in hex.
*/
#define DKEY(x) mdb_dkey(x, kbuf)
#else
#define DKBUF
#define DKEY(x) 0
#endif
/** An invalid page number.
* Mainly used to denote an empty tree.
*/
#define P_INVALID (~(pgno_t)0)
/** Test if the flags \b f are set in a flag word \b w. */
#define F_ISSET(w, f) (((w) & (f)) == (f))
/** Round \b n up to an even number. */
#define EVEN(n) (((n) + 1U) & -2) /* sign-extending -2 to match n+1U */
/** Least significant 1-bit of \b n. n must be of an unsigned type. */
#define LOW_BIT(n) ((n) & (-(n)))
/** (log2(\b p2) % \b n), for p2 = power of 2 and 0 < n < 8. */
#define LOG2_MOD(p2, n) (7 - 86 / ((p2) % ((1U<<(n))-1) + 11))
/* Explanation: Let p2 = 2**(n*y + x), x<n and M = (1U<<n)-1. Now p2 =
* (M+1)**y * 2**x = 2**x (mod M). Finally "/" "happens" to return 7-x.
*/
/** Should be alignment of \b type. Ensure it is a power of 2. */
#define ALIGNOF2(type) \
LOW_BIT(offsetof(struct { char ch_; type align_; }, align_))
/** Used for offsets within a single page.
* Since memory pages are typically 4 or 8KB in size, 12-13 bits,
* this is plenty.
*/
typedef uint16_t indx_t;
typedef unsigned long long mdb_hash_t;
/** Default size of memory map.
* This is certainly too small for any actual applications. Apps should always set
* the size explicitly using #mdb_env_set_mapsize().
*/
#define DEFAULT_MAPSIZE 1048576
/** @defgroup readers Reader Lock Table
* Readers don't acquire any locks for their data access. Instead, they
* simply record their transaction ID in the reader table. The reader
* mutex is needed just to find an empty slot in the reader table. The
* slot's address is saved in thread-specific data so that subsequent read
* transactions started by the same thread need no further locking to proceed.
*
* If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
*
* No reader table is used if the database is on a read-only filesystem, or
* if #MDB_NOLOCK is set.
*
* Since the database uses multi-version concurrency control, readers don't
* actually need any locking. This table is used to keep track of which
* readers are using data from which old transactions, so that we'll know
* when a particular old transaction is no longer in use. Old transactions
* that have discarded any data pages can then have those pages reclaimed
* for use by a later write transaction.
*
* The lock table is constructed such that reader slots are aligned with the
* processor's cache line size. Any slot is only ever used by one thread.
* This alignment guarantees that there will be no contention or cache
* thrashing as threads update their own slot info, and also eliminates
* any need for locking when accessing a slot.
*
* A writer thread will scan every slot in the table to determine the oldest
* outstanding reader transaction. Any freed pages older than this will be
* reclaimed by the writer. The writer doesn't use any locks when scanning
* this table. This means that there's no guarantee that the writer will
* see the most up-to-date reader info, but that's not required for correct
* operation - all we need is to know the upper bound on the oldest reader,
* we don't care at all about the newest reader. So the only consequence of
* reading stale information here is that old pages might hang around a
* while longer before being reclaimed. That's actually good anyway, because
* the longer we delay reclaiming old pages, the more likely it is that a
* string of contiguous pages can be found after coalescing old pages from
* many old transactions together.
* @{
*/
/** Number of slots in the reader table.
* This value was chosen somewhat arbitrarily. 126 readers plus a
* couple mutexes fit exactly into 8KB on my development machine.
* Applications should set the table size using #mdb_env_set_maxreaders().
*/
#define DEFAULT_READERS 126
/** The size of a CPU cache line in bytes. We want our lock structures
* aligned to this size to avoid false cache line sharing in the
* lock table.
* This value works for most CPUs. For Itanium this should be 128.
*/
#ifndef CACHELINE
#define CACHELINE 64
#endif
/** The information we store in a single slot of the reader table.
* In addition to a transaction ID, we also record the process and
* thread ID that owns a slot, so that we can detect stale information,
* e.g. threads or processes that went away without cleaning up.
* @note We currently don't check for stale records. We simply re-init
* the table when we know that we're the only process opening the
* lock file.
*/
typedef struct MDB_rxbody {
/** Current Transaction ID when this transaction began, or (txnid_t)-1.
* Multiple readers that start at the same time will probably have the
* same ID here. Again, it's not important to exclude them from
* anything; all we need to know is which version of the DB they
* started from so we can avoid overwriting any data used in that
* particular version.
*/
volatile txnid_t mrb_txnid;
/** The process ID of the process owning this reader txn. */
volatile MDB_PID_T mrb_pid;
/** The thread ID of the thread owning this txn. */
volatile MDB_THR_T mrb_tid;
} MDB_rxbody;
/** The actual reader record, with cacheline padding. */
typedef struct MDB_reader {
union {
MDB_rxbody mrx;
/** shorthand for mrb_txnid */
#define mr_txnid mru.mrx.mrb_txnid
#define mr_pid mru.mrx.mrb_pid
#define mr_tid mru.mrx.mrb_tid
/** cache line alignment */
char pad[(sizeof(MDB_rxbody)+CACHELINE-1) & ~(CACHELINE-1)];
} mru;
} MDB_reader;
/** The header for the reader table.
* The table resides in a memory-mapped file. (This is a different file
* than is used for the main database.)
*
* For POSIX the actual mutexes reside in the shared memory of this
* mapped file. On Windows, mutexes are named objects allocated by the
* kernel; we store the mutex names in this mapped file so that other
* processes can grab them. This same approach is also used on
* MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
* process-shared POSIX mutexes. For these cases where a named object
* is used, the object name is derived from a 64 bit FNV hash of the
* environment pathname. As such, naming collisions are extremely
* unlikely. If a collision occurs, the results are unpredictable.
*/
typedef struct MDB_txbody {
/** Stamp identifying this as an LMDB file. It must be set
* to #MDB_MAGIC. */
uint32_t mtb_magic;
/** Format of this lock file. Must be set to #MDB_LOCK_FORMAT. */
uint32_t mtb_format;
/** The ID of the last transaction committed to the database.
* This is recorded here only for convenience; the value can always
* be determined by reading the main database meta pages.
*/
volatile txnid_t mtb_txnid;
/** The number of slots that have been used in the reader table.
* This always records the maximum count, it is not decremented
* when readers release their slots.
*/
volatile unsigned mtb_numreaders;
#if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
/** Binary form of names of the reader/writer locks */
mdb_hash_t mtb_mutexid;
#elif defined(MDB_USE_SYSV_SEM)
int mtb_semid;
int mtb_rlocked;
#else
/** Mutex protecting access to this table.
* This is the reader table lock used with LOCK_MUTEX().
*/
mdb_mutex_t mtb_rmutex;
#endif
} MDB_txbody;
/** The actual reader table definition. */
typedef struct MDB_txninfo {
union {
MDB_txbody mtb;
#define mti_magic mt1.mtb.mtb_magic
#define mti_format mt1.mtb.mtb_format
#define mti_rmutex mt1.mtb.mtb_rmutex
#define mti_txnid mt1.mtb.mtb_txnid
#define mti_numreaders mt1.mtb.mtb_numreaders
#define mti_mutexid mt1.mtb.mtb_mutexid
#ifdef MDB_USE_SYSV_SEM
#define mti_semid mt1.mtb.mtb_semid
#define mti_rlocked mt1.mtb.mtb_rlocked
#endif
char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
} mt1;
#if !(defined(_WIN32) || defined(MDB_USE_POSIX_SEM))
union {
#ifdef MDB_USE_SYSV_SEM
int mt2_wlocked;
#define mti_wlocked mt2.mt2_wlocked
#else
mdb_mutex_t mt2_wmutex;
#define mti_wmutex mt2.mt2_wmutex
#endif
char pad[(MNAME_LEN+CACHELINE-1) & ~(CACHELINE-1)];
} mt2;
#endif
MDB_reader mti_readers[1];
} MDB_txninfo;
/** Lockfile format signature: version, features and field layout */
#define MDB_LOCK_FORMAT \
((uint32_t) \
(((MDB_LOCK_VERSION) % (1U << MDB_LOCK_VERSION_BITS)) \
+ MDB_lock_desc * (1U << MDB_LOCK_VERSION_BITS)))
/** Lock type and layout. Values 0-119. _WIN32 implies #MDB_PIDLOCK.
* Some low values are reserved for future tweaks.
*/
#ifdef _WIN32
# define MDB_LOCK_TYPE (0 + ALIGNOF2(mdb_hash_t)/8 % 2)
#elif defined MDB_USE_POSIX_SEM
# define MDB_LOCK_TYPE (4 + ALIGNOF2(mdb_hash_t)/8 % 2)
#elif defined MDB_USE_SYSV_SEM
# define MDB_LOCK_TYPE (8)
#elif defined MDB_USE_POSIX_MUTEX
/* We do not know the inside of a POSIX mutex and how to check if mutexes
* used by two executables are compatible. Just check alignment and size.
*/
# define MDB_LOCK_TYPE (10 + \
LOG2_MOD(ALIGNOF2(pthread_mutex_t), 5) + \
sizeof(pthread_mutex_t) / 4U % 22 * 5)
#endif
enum {
/** Magic number for lockfile layout and features.
*
* This *attempts* to stop liblmdb variants compiled with conflicting
* options from using the lockfile at the same time and thus breaking
* it. It describes locking types, and sizes and sometimes alignment
* of the various lockfile items.
*
* The detected ranges are mostly guesswork, or based simply on how
* big they could be without using more bits. So we can tweak them
* in good conscience when updating #MDB_LOCK_VERSION.
*/
MDB_lock_desc =
/* Default CACHELINE=64 vs. other values (have seen mention of 32-256) */
(CACHELINE==64 ? 0 : 1 + LOG2_MOD(CACHELINE >> (CACHELINE>64), 5))
+ 6 * (sizeof(MDB_PID_T)/4 % 3) /* legacy(2) to word(4/8)? */
+ 18 * (sizeof(pthread_t)/4 % 5) /* can be struct{id, active data} */
+ 90 * (sizeof(MDB_txbody) / CACHELINE % 3)
+ 270 * (MDB_LOCK_TYPE % 120)
/* The above is < 270*120 < 2**15 */
+ ((sizeof(txnid_t) == 8) << 15) /* 32bit/64bit */
+ ((sizeof(MDB_reader) > CACHELINE) << 16)
/* Not really needed - implied by MDB_LOCK_TYPE != (_WIN32 locking) */
+ (((MDB_PIDLOCK) != 0) << 17)
/* 18 bits total: Must be <= (32 - MDB_LOCK_VERSION_BITS). */
};
/** @} */
/** Common header for all page types. The page type depends on #mp_flags.
*
* #P_BRANCH and #P_LEAF pages have unsorted '#MDB_node's at the end, with
* sorted #mp_ptrs[] entries referring to them. Exception: #P_LEAF2 pages
* omit mp_ptrs and pack sorted #MDB_DUPFIXED values after the page header.
*
* #P_OVERFLOW records occupy one or more contiguous pages where only the
* first has a page header. They hold the real data of #F_BIGDATA nodes,
* and the node stores the pgno and number of pages used by the record.
*
* #P_SUBP sub-pages are small leaf "pages" with duplicate data.
* A node with flag #F_DUPDATA but not #F_SUBDATA contains a sub-page.
* (Duplicate data can also go in sub-databases, which use normal pages.)
*
* #P_META pages contain #MDB_meta, the start point of an LMDB snapshot.
*
* Each non-metapage up to #MDB_meta.%mm_last_pg is reachable exactly once
* in the snapshot: Either used by a database or listed in a freeDB record.
*/
typedef struct MDB_page_header {
#define mp_pgno mp_p.p_pgno
#define mp_next mp_p.p_next
union {
pgno_t p_pgno; /**< page number */
struct MDB_page *p_next; /**< for in-memory list of freed pages */
} mh_p;
/** If page is clean: snapshot txnid, dirty: txn workid, metapage: unused.
*
* The value indicates which snapshot/#MDB_txn the page belongs to.
* Tested with #IS_MUTABLE(), #IS_WRITABLE(), #IS_DIRTY_NW().
*
* (clean page).mp_txnid == txnid of creator < txnid of later txns.
* (dirty page).mp_txnid >= mt_workid of creator txn.
* (dirty page).mt_txnid < mt_workid of children of creator txn.
*
* Thus an #MDB_txn can write to pages with mp_txnid >= txn.mt_workid.
* A page with smaller mp_txnid is dirty in an ancestor txn or clean.
*
* Non-#MDB_WRITEMAP sets txn.mt_workid > txn.mt_txnid, to tell apart
* spilled and dirty pages. WRITEMAP sets mt_workid = mt_txnid, since
* it does not copy/spill pages. Thus (page.mp_txnid == txn.mt_txnid)
* says "spilled page" without WRITEMAP, "dirty page" with WRITEMAP.
*
* Finally, ((dirty page).mp_txnid & #MDB_PGTXNID_FLAGMASK) can be used
* for flags with non-WRITEMAP; it keeps low bits in workid = 0.
*/
txnid_t mh_txnid;
uint16_t mh_pad; /**< key size if this is a LEAF2 page */
/** @defgroup mdb_page Page Flags
* @ingroup internal
* Flags for the page headers.
* @{
*/
#define P_BRANCH 0x01 /**< branch page */
#define P_LEAF 0x02 /**< leaf page */
#define P_OVERFLOW 0x04 /**< overflow page */
#define P_META 0x08 /**< meta page */
#define P_LEAF2 0x20 /**< for #MDB_DUPFIXED records */
#define P_SUBP 0x40 /**< for #MDB_DUPSORT sub-pages */
#define P_DIRTY_OVF 0x2000 /**< page has dirty overflow nodes */
#define P_LOOSE 0x4000 /**< page was dirtied then freed, can be reused */
#define P_KEEP 0x8000 /**< leave this page alone during spill */
/** Persistent flags for page administration rather than page contents */
#define P_ADM_FLAGS 0 /* later... */
/** @} */
uint16_t mh_flags; /**< @ref mdb_page */
#define mp_lower mp_pb.pb.pb_lower
#define mp_upper mp_pb.pb.pb_upper
#define mp_pages mp_pb.pb_pages
union {
struct {
indx_t pb_lower; /**< lower bound of free space */
indx_t pb_upper; /**< upper bound of free space */
} pb;
uint32_t pb_pages; /**< number of overflow pages */
} mh_pb;
} MDB_page_header;
typedef struct MDB_page {
MDB_page_header mp_hdr;
#define mp_p mp_hdr.mh_p
#define mp_txnid mp_hdr.mh_txnid
#define mp_pad mp_hdr.mh_pad
#define mp_flags mp_hdr.mh_flags
#define mp_pb mp_hdr.mh_pb
indx_t mp_ptrs[1]; /**< dynamic size */
} MDB_page;
/** Size of the page header, excluding dynamic data at the end */
#define PAGEHDRSZ ((unsigned)sizeof(MDB_page_header))
/** Address of first usable data byte in a page, after the header */
#define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
/** ITS#7713, change PAGEBASE to handle 65536 byte pages */
#define PAGEBASE PAGEHDRSZ
/** Number of nodes on a page */
#define NUMKEYS(p) (((p)->mp_lower - (PAGEHDRSZ-PAGEBASE)) >> 1)
/** The amount of space remaining in the page */
#define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
/** The percentage of space used in the page, in tenths of a percent. */
#define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
((env)->me_psize - PAGEHDRSZ))
/** The minimum page fill factor, in tenths of a percent.
* Pages emptier than this are candidates for merging.
*/
#define FILL_THRESHOLD 250
/** Test if a page is a leaf page */
#define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF)
/** Test if a page is a LEAF2 page */
#define IS_LEAF2(p) F_ISSET((p)->mp_flags, P_LEAF2)
/** Test if a page is a branch page */
#define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH)
/** Test if a page is an overflow page */
#define IS_OVERFLOW(p) F_ISSET((p)->mp_flags, P_OVERFLOW)
/** Test if a page is a sub page */
#define IS_SUBP(p) F_ISSET((p)->mp_flags, P_SUBP)
/** Test if (this non-sub page is dirty && env is non-#MDB_WRITEMAP) */
#define IS_DIRTY_NW(txn, p) ((p)->mp_txnid > (txn)->mt_txnid)
/** Test if this non-sub page belongs to the current snapshot */
#define IS_MUTABLE(txn, p) ((p)->mp_txnid >= (txn)->mt_txnid)
/** Test if this non-sub page is writable in this txn (not an ancestor) */
#define IS_WRITABLE(txn, p) ((p)->mp_txnid >= (txn)->mt_workid)
/** Info about overflow page, stored in an F_BIGDATA node */
typedef struct MDB_ovpage {
pgno_t op_pgno;
txnid_t op_txnid;
mdb_size_t op_pages;
} MDB_ovpage;
#if OVERFLOW_NOTYET
/** Header for a dirty overflow page in memory */
typedef struct MDB_dovpage {
MDB_page_header mp_hdr;
void *mp_ptr;
} MDB_dovpage;
#endif
/** The number of overflow pages needed to store the given size. */
#define OVPAGES(size, psize) ((PAGEHDRSZ-1 + (size)) / (psize) + 1)
/** Link in #MDB_txn.%mt_loose_pgs list.
* Kept outside the page header, which is needed when reusing the page.
*/
#define NEXT_LOOSE_PAGE(p) (*(MDB_page **)((p) + 2))
/** Mark the page as writable by this txn */
#ifndef MDB_TEST
#define SET_PGTXNID(txn, mp) ((mp)->mp_txnid = (txn)->mt_workid)
#else
#define SET_PGTXNID(txn, mp) \
((mp)->mp_txnid = (txn)->mt_workid \
/* random unused "flags" added when not WRITEMAP for debugging */ \
| (((txn)->mt_flags & MDB_TXN_WRITEMAP) ? 0 : \
(MDB_RAND((size_t)(txn)) >> (32-MDB_PGTXNID_FLAGBITS))))
#define MDB_RAND(x) (mdb_rnd = (mdb_rnd + (unsigned)(x)) * 987654321 + 54321)
static volatile unsigned mdb_rnd;
#endif
/** mp_txnid bits reserved in dirty pages for flags.
* TODO: For future code with header-free ovpages, if we omit mp_flags
* from the "header" kept elsewhere. Otherwise, drop this code.
*/
#define MDB_PGTXNID_FLAGBITS 4
#define MDB_PGTXNID_STEP ((txnid_t)1 << MDB_PGTXNID_FLAGBITS)
#define MDB_PGTXNID_FLAGMASK (MDB_PGTXNID_STEP-1)
/** Header for a single key/data pair within a page.
* Used in pages of type #P_BRANCH and #P_LEAF without #P_LEAF2.
* We guarantee 2-byte alignment for 'MDB_node's.
*
* #mn_lo and #mn_hi are used for data size on leaf nodes, and for child
* pgno on branch nodes. On 64 bit platforms, #mn_flags is also used
* for pgno. (Branch nodes have no flags). Lo and hi are in host byte
* order in case some accesses can be optimized to 32-bit word access.
*
* Leaf node flags describe node contents. #F_BIGDATA says the node's
* data part is an MDB_ovpage struct pointing to a page with actual data.
* #F_DUPDATA and #F_SUBDATA can be combined giving duplicate data in
* a sub-page/sub-database, and named databases (just #F_SUBDATA).
*/
typedef struct MDB_node {
/** part of data size or pgno
* @{ */
#if BYTE_ORDER == LITTLE_ENDIAN
unsigned short mn_lo, mn_hi;
#else
unsigned short mn_hi, mn_lo;
#endif
/** @} */
/** @defgroup mdb_node Node Flags
* @ingroup internal
* Flags for node headers.
* @{
*/
#define F_BIGDATA 0x01 /**< data put on overflow page */
#define F_SUBDATA 0x02 /**< data is a sub-database */
#define F_DUPDATA 0x04 /**< data has duplicates */
/** valid flags for #mdb_node_add() */
#define NODE_ADD_FLAGS (F_DUPDATA|F_SUBDATA|MDB_RESERVE|MDB_APPEND)
/** @} */
unsigned short mn_flags; /**< @ref mdb_node */
unsigned short mn_ksize; /**< key size */
char mn_data[1]; /**< key and data are appended here */
} MDB_node;
/** Size of the node header, excluding dynamic data at the end */
#define NODESIZE offsetof(MDB_node, mn_data)
/** Bit position of top word in page number, for shifting mn_flags */
#define PGNO_TOPWORD ((pgno_t)-1 > 0xffffffffu ? 32 : 0)
/** Size of a node in a branch page with a given key.
* This is just the node header plus the key, there is no data.
*/
#define INDXSIZE(k) (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
/** Size of a node in a leaf page with a given key and data.
* This is node header plus key plus data size.
*/
#define LEAFSIZE(k, d) (NODESIZE + (k)->mv_size + (d)->mv_size)
/** Address of node \b i in page \b p */
#define NODEPTR(p, i) ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i] + PAGEBASE))
/** Address of the key for the node */
#define NODEKEY(node) (void *)((node)->mn_data)
/** Address of the data for a node */
#define NODEDATA(node) (void *)((char *)(node)->mn_data + (node)->mn_ksize)
/** Get the page number pointed to by a branch node */
#define NODEPGNO(node) \
((node)->mn_lo | ((pgno_t) (node)->mn_hi << 16) | \
(PGNO_TOPWORD ? ((pgno_t) (node)->mn_flags << PGNO_TOPWORD) : 0))
/** Set the page number in a branch node */
#define SETPGNO(node,pgno) do { \
(node)->mn_lo = (pgno) & 0xffff; (node)->mn_hi = (pgno) >> 16; \
if (PGNO_TOPWORD) (node)->mn_flags = (pgno) >> PGNO_TOPWORD; } while(0)
/** Get the size of the data in a leaf node */
#define NODEDSZ(node) ((node)->mn_lo | ((unsigned)(node)->mn_hi << 16))
/** Set the size of the data for a leaf node */
#define SETDSZ(node,size) do { \
(node)->mn_lo = (size) & 0xffff; (node)->mn_hi = (size) >> 16;} while(0)
/** The size of a key in a node */
#define NODEKSZ(node) ((node)->mn_ksize)
/** Copy a page number from src to dst */
#ifdef MISALIGNED_OK
#define COPY_PGNO(dst,src) dst = src
#else
#if MDB_SIZE_MAX > 0xffffffffU
#define COPY_PGNO(dst,src) do { \
unsigned short *s, *d; \
s = (unsigned short *)&(src); \
d = (unsigned short *)&(dst); \
*d++ = *s++; \
*d++ = *s++; \
*d++ = *s++; \
*d = *s; \
} while (0)
#else
#define COPY_PGNO(dst,src) do { \
unsigned short *s, *d; \
s = (unsigned short *)&(src); \
d = (unsigned short *)&(dst); \
*d++ = *s++; \
*d = *s; \
} while (0)
#endif
#endif
/** The address of a key in a LEAF2 page.
* LEAF2 pages are used for #MDB_DUPFIXED sorted-duplicate sub-DBs.
* There are no node headers, keys are stored contiguously.
*/
#define LEAF2KEY(p, i, ks) ((char *)(p) + PAGEHDRSZ + ((i)*(ks)))
/** Set the \b node's key into \b keyptr, if requested. */
#define MDB_GET_KEY(node, keyptr) { if ((keyptr) != NULL) { \
(keyptr)->mv_size = NODEKSZ(node); (keyptr)->mv_data = NODEKEY(node); } }
/** Set the \b node's key into \b key. */
#define MDB_GET_KEY2(node, key) { key.mv_size = NODEKSZ(node); key.mv_data = NODEKEY(node); }
/** Information about a single database in the environment. */
typedef struct MDB_db {
uint32_t md_pad; /**< also ksize for LEAF2 pages */
uint16_t md_flags; /**< @ref mdb_dbi_open */
uint16_t md_depth; /**< depth of this tree */
pgno_t md_branch_pages; /**< number of internal pages */
pgno_t md_leaf_pages; /**< number of leaf pages */
pgno_t md_overflow_pages; /**< number of overflow pages */
mdb_size_t md_entries; /**< number of data items */
pgno_t md_root; /**< the root page of this tree */
} MDB_db;
#define MDB_VALID 0x8000 /**< DB handle is valid, for me_dbflags */
#define PERSISTENT_FLAGS (0xffff & ~(MDB_VALID))
/** #mdb_dbi_open() flags */
#define VALID_FLAGS (MDB_REVERSEKEY|MDB_DUPSORT|MDB_INTEGERKEY|MDB_DUPFIXED|\
MDB_INTEGERDUP|MDB_REVERSEDUP|MDB_CREATE)
/** Handle for the DB used to track free pages. */
#define FREE_DBI 0
/** Handle for the default DB. */
#define MAIN_DBI 1
/** Number of DBs in metapage (free and main) - also hardcoded elsewhere */
#define CORE_DBS 2
/** Number of meta pages - also hardcoded elsewhere */
#define NUM_METAS 2
/** Meta page content.
* A meta page is the start point for accessing a database snapshot.
* Pages 0-1 are meta pages. Transaction N writes meta page #(N % 2).
*/
typedef struct MDB_meta {
/** Stamp identifying this as an LMDB file. It must be set
* to #MDB_MAGIC. */
uint32_t mm_magic;
/** Version number of this file. Must be set to #MDB_DATA_VERSION. */
uint32_t mm_version;
#ifdef MDB_VL32
union { /* always zero since we don't support fixed mapping in MDB_VL32 */
MDB_ID mmun_ull;
void *mmun_address;
} mm_un;
#define mm_address mm_un.mmun_address
#else
void *mm_address; /**< address for fixed mapping */
#endif
mdb_size_t mm_mapsize; /**< size of mmap region */
MDB_db mm_dbs[CORE_DBS]; /**< first is free space, 2nd is main db */
/** The size of pages used in this DB */
#define mm_psize mm_dbs[FREE_DBI].md_pad
/** Any persistent environment flags. @ref mdb_env */
#define mm_flags mm_dbs[FREE_DBI].md_flags
/** Last used page in the datafile.
* Actually the file may be shorter if the freeDB lists the final pages.
*/
pgno_t mm_last_pg;
volatile txnid_t mm_txnid; /**< txnid that committed this page */
} MDB_meta;
/** Buffer for a stack-allocated meta page.
* The members define size and alignment, and silence type
* aliasing warnings. They are not used directly; that could
* mean incorrectly using several union members in parallel.
*/
typedef union MDB_metabuf {
MDB_page mb_page;
struct {
char mm_pad[PAGEHDRSZ];
MDB_meta mm_meta;
} mb_metabuf;
} MDB_metabuf;
/** Auxiliary DB info.
* The information here is mostly static/read-only. There is
* only a single copy of this record in the environment.
*/
typedef struct MDB_dbx {
MDB_val md_name; /**< name of the database */
MDB_cmp_func *md_cmp; /**< function for comparing keys */
MDB_cmp_func *md_dcmp; /**< function for comparing data items */
MDB_rel_func *md_rel; /**< user relocate function */
void *md_relctx; /**< user-provided context for md_rel */
} MDB_dbx;
/** A database transaction.
* Every operation requires a transaction handle.
*/
struct MDB_txn {
MDB_txn *mt_parent; /**< parent of a nested txn */
/** Nested txn under this txn, set together with flag #MDB_TXN_HAS_CHILD */
MDB_txn *mt_child;
pgno_t mt_next_pgno; /**< next unallocated page */
#if MDB_RPAGE_CACHE
pgno_t mt_last_pgno; /**< last written page */
#endif
/** The ID of this transaction. IDs are integers incrementing from 1.
* Only committed write transactions increment the ID. If a transaction
* aborts, the ID may be re-used by the next writer.
*/
txnid_t mt_txnid;
/** Written to mp_txnid of dirty pages, to be fixed by #mdb_page_flush().
*
* Value >= WRITEMAP ? txnid : 1 + (parent ? parent.last_workid : txnid).
* See #MDB_page.%mp_txnid.
*
* An MDB_txn can write to a page when page.mp_txnid >= txn.mt_workid.
* New children get bigger workid than pages dirty in their parent
* (i.e. bigger than parent.mt_last_workid). When children commit,
* they copy #mt_last_workid to the parent to match their pages.
*/
txnid_t mt_workid;
/** Current max mp_txnid of the MDB_txn's dirty pages: Starts as
* #mt_workid, then grows as it is copied from children who commit.
*/
txnid_t mt_last_workid;
MDB_env *mt_env; /**< the DB environment */
/** The list of pages that became unused during this transaction.
*/
MDB_IDL mt_free_pgs;
/** The list of loose pages that became unused and may be reused
* in this transaction, linked through #NEXT_LOOSE_PAGE(page).
*/
MDB_page *mt_loose_pgs;
/** Number of loose pages (#mt_loose_pgs) */
int mt_loose_count;
/** The sorted list of dirty pages we temporarily wrote to disk
* because the dirty list was full. page numbers in here are
* shifted left by 1, deleted slots have the LSB set.
* Unused with #MDB_WRITEMAP, which does not use a dirty list.
*/
MDB_IDL mt_spill_pgs;
union {
/** For write txns: Modified pages, sorted. Unused when MDB_WRITEMAP. */
MDB_ID2L dirty_list;
/** For read txns: This thread/txn's reader table slot, or NULL. */
MDB_reader *reader;
} mt_u;
#if OVERFLOW_NOTYET
/** The sorted list of dirty overflow pages. */
MDB_ID2L mt_dirty_ovs;
#endif
/** Array of records for each DB known in the environment. */
MDB_dbx *mt_dbxs;
/** Array of MDB_db records for each known DB */
MDB_db *mt_dbs;
/** Array of sequence numbers for each DB handle */
unsigned int *mt_dbiseqs;
/** @defgroup mt_dbflag Transaction DB Flags
* @ingroup internal
* @{
*/
#define DB_DIRTY 0x01 /**< DB was written in this txn */
#define DB_STALE 0x02 /**< Named-DB record is older than txnID */
#define DB_NEW 0x04 /**< Named-DB handle opened in this txn */
#define DB_VALID 0x08 /**< DB handle is valid, see also #MDB_VALID */
#define DB_USRVALID 0x10 /**< As #DB_VALID, but not set for #FREE_DBI */
#define DB_DUPDATA 0x20 /**< DB is #MDB_DUPSORT data */
/** @} */
/** In write txns, array of cursors for each DB */
MDB_cursor **mt_cursors;
/** Array of flags for each DB */
unsigned char *mt_dbflags;
#if MDB_RPAGE_CACHE
/** List of read-only pages (actually chunks) */
MDB_ID3L mt_rpages;
/** We map chunks of 16 pages. Even though Windows uses 4KB pages, all
* mappings must begin on 64KB boundaries. So we round off all pgnos to
* a chunk boundary. We do the same on Linux for symmetry, and also to
* reduce the frequency of mmap/munmap calls.
*/
#define MDB_RPAGE_CHUNK 16
#define MDB_TRPAGE_SIZE 4096 /**< size of #mt_rpages array of chunks */
#define MDB_TRPAGE_MAX (MDB_TRPAGE_SIZE-1) /**< maximum chunk index */
unsigned int mt_rpcheck; /**< threshold for reclaiming unref'd chunks */
#endif
/** Number of DB records in use, or 0 when the txn is finished.
* This number only ever increments until the txn finishes; we
* don't decrement it when individual DB handles are closed.
*/
MDB_dbi mt_numdbs;
/** @defgroup mdb_txn Transaction Flags
* @ingroup internal
* @{
*/
/** #mdb_txn_begin() flags */
#define MDB_TXN_BEGIN_FLAGS (MDB_NOMETASYNC|MDB_NOSYNC|MDB_RDONLY)
#define MDB_TXN_NOMETASYNC MDB_NOMETASYNC /**< don't sync meta for this txn on commit */
#define MDB_TXN_NOSYNC MDB_NOSYNC /**< don't sync this txn on commit */
#define MDB_TXN_RDONLY MDB_RDONLY /**< read-only transaction */
/* internal txn flags */
#define MDB_TXN_WRITEMAP MDB_WRITEMAP /**< copy of #MDB_env flag in writers */
#define MDB_TXN_FINISHED 0x01 /**< txn is finished or never began */
#define MDB_TXN_ERROR 0x02 /**< txn is unusable after an error */
#define MDB_TXN_DIRTY 0x04 /**< must write, even if dirty list is empty */
#define MDB_TXN_SPILLS 0x08 /**< txn or a parent has spilled pages */
#define MDB_TXN_HAS_CHILD 0x10 /**< txn has an #MDB_txn.%mt_child */
#define MDB_TXN_DIRTYNUM 0x20 /**< dirty list uses nump list */
/** most operations on the txn are currently illegal */
#define MDB_TXN_BLOCKED (MDB_TXN_FINISHED|MDB_TXN_ERROR|MDB_TXN_HAS_CHILD)
/** @} */
unsigned int mt_flags; /**< @ref mdb_txn */
/** #dirty_list room: Array size - \#dirty pages visible to this txn.
* Includes ancestor txns' dirty pages not hidden by other txns'
* dirty/spilled pages. Thus commit(nested txn) has room to merge
* dirty_list into mt_parent after freeing hidden mt_parent pages.
* When #MDB_WRITEMAP, it is nonzero but otherwise irrelevant.
*/
unsigned int mt_dirty_room;
};
/** Enough space for 2^32 nodes with minimum of 2 keys per node. I.e., plenty.
* At 4 keys per node, enough for 2^64 nodes, so there's probably no need to
* raise this on a 64 bit machine.
*/
#define CURSOR_STACK 32
struct MDB_xcursor;
/** Cursors are used for all DB operations.
* A cursor holds a path of (page pointer, key index) from the DB
* root to a position in the DB, plus other state. #MDB_DUPSORT
* cursors include an xcursor to the current data item. Write txns
* track their cursors and keep them up to date when data moves.
* Exception: An xcursor's pointer to a #P_SUBP page can be stale.
* (A node with #F_DUPDATA but no #F_SUBDATA contains a subpage).
*/
struct MDB_cursor {
/** Next cursor on this DB in this txn */
MDB_cursor *mc_next;
/** Backup of the original cursor if this cursor is a shadow */
MDB_cursor *mc_backup;
/** Context used for databases with #MDB_DUPSORT, otherwise NULL */
struct MDB_xcursor *mc_xcursor;
/** The transaction that owns this cursor */
MDB_txn *mc_txn;
/** The database handle this cursor operates on */
MDB_dbi mc_dbi;
/** The database record for this cursor */
MDB_db *mc_db;
/** The database auxiliary record for this cursor */
MDB_dbx *mc_dbx;
/** The @ref mt_dbflag for this database */
unsigned char *mc_dbflag;
unsigned short mc_snum; /**< number of pushed pages */
unsigned short mc_top; /**< index of top page, normally mc_snum-1 */
/** @defgroup mdb_cursor Cursor Flags
* @ingroup internal
* Cursor state flags.
* @{
*/
#define C_INITIALIZED 0x01 /**< cursor has been initialized and is valid */
#define C_EOF 0x02 /**< No more data */
#define C_SUB 0x04 /**< Cursor is a sub-cursor */
#define C_DEL 0x08 /**< last op was a cursor_del */
#define C_UNTRACK 0x40 /**< Un-track cursor when closing */
#define C_WRITEMAP MDB_TXN_WRITEMAP /**< Copy of txn flag */
/** Read-only cursor into the txn's original snapshot in the map.
* Set for read-only txns, and in #mdb_page_alloc() for #FREE_DBI when
* #MDB_DEVEL & 2. Only implements code which is necessary for this.
*/
#define C_ORIG_RDONLY MDB_TXN_RDONLY
/** @} */
unsigned int mc_flags; /**< @ref mdb_cursor */
MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */
indx_t mc_ki[CURSOR_STACK]; /**< stack of page indices */
#if MDB_RPAGE_CACHE
MDB_page *mc_ovpg; /**< a referenced overflow page */
# define MC_OVPG(mc) ((mc)->mc_ovpg)
# define MC_SET_OVPG(mc, pg) \
((mc)->mc_ovpg = \
(MDB_REMAPPING((mc)->mc_txn->mt_env->me_flags) ? (pg) : NULL))
#else
# define MC_OVPG(mc) ((MDB_page *)0)
# define MC_SET_OVPG(mc, pg) ((void)0)
#endif
};
/** Context for sorted-dup records.
* We could have gone to a fully recursive design, with arbitrarily
* deep nesting of sub-databases. But for now we only handle these
* levels - main DB, optional sub-DB, sorted-duplicate DB.
*/
typedef struct MDB_xcursor {
/** A sub-cursor for traversing the Dup DB */
MDB_cursor mx_cursor;
/** The database record for this Dup DB */
MDB_db mx_db;
/** The auxiliary DB record for this Dup DB */
MDB_dbx mx_dbx;
/** The @ref mt_dbflag for this Dup DB */
unsigned char mx_dbflag;
} MDB_xcursor;
/** Check if there is an inited xcursor */
#define XCURSOR_INITED(mc) \
((mc)->mc_xcursor && ((mc)->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
/** Update the xcursor's sub-page pointer, if any, in \b mc. Needed
* when the node which contains the sub-page may have moved. Called
* with leaf page \b mp = mc->mc_pg[\b top].
*/
#define XCURSOR_REFRESH(mc, top, mp) do { \
MDB_page *xr_pg = (mp); \
MDB_node *xr_node; \
if (!XCURSOR_INITED(mc) || (mc)->mc_ki[top] >= NUMKEYS(xr_pg)) break; \
xr_node = NODEPTR(xr_pg, (mc)->mc_ki[top]); \
if ((xr_node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) \
(mc)->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(xr_node); \
} while (0)
/** State of FreeDB old pages, stored in the MDB_env */
typedef struct MDB_pgstate {
pgno_t *mf_pghead; /**< Reclaimed freeDB pages, or NULL before use */
txnid_t mf_pglast; /**< ID of last used record, or 0 if !mf_pghead */
} MDB_pgstate;
/** The database environment. */
struct MDB_env {
HANDLE me_fd; /**< The main data file */
HANDLE me_lfd; /**< The lock file */
HANDLE me_mfd; /**< For writing and syncing the meta pages */
#ifdef _WIN32
#ifdef MDB_RPAGE_CACHE
HANDLE me_fmh; /**< File Mapping handle */
#endif
HANDLE me_ovfd; /**< Overlapped/async with write-through file handle */
#endif /* _WIN32 */
/** Failed to update the meta page. Probably an I/O error. */
#define MDB_FATAL_ERROR 0x80000000U
/** using a raw block device */
#define MDB_RAWPART 0x40000000U
/** Some fields are initialized. */
#define MDB_ENV_ACTIVE 0x20000000U
/** me_txkey is set */
#define MDB_ENV_TXKEY 0x10000000U
/** fdatasync is unreliable */
#define MDB_FSYNCONLY 0x08000000U
uint32_t me_flags; /**< @ref mdb_env */
unsigned int me_psize; /**< DB page size, inited from me_os_psize */
unsigned int me_os_psize; /**< OS page size, from #GET_PAGESIZE */
unsigned int me_maxreaders; /**< size of the reader table */
/** Max #MDB_txninfo.%mti_numreaders of interest to #mdb_env_close() */
volatile int me_close_readers;
MDB_dbi me_numdbs; /**< number of DBs opened */
MDB_dbi me_maxdbs; /**< size of the DB table */
MDB_PID_T me_pid; /**< process ID of this env */
char *me_path; /**< path to the DB files */
char *me_map; /**< the memory map of the data file */
MDB_txninfo *me_txns; /**< the memory map of the lock file or NULL */
MDB_meta *me_metas[NUM_METAS]; /**< pointers to the two meta pages */
void *me_pbuf; /**< scratch area for DUPSORT put() */
MDB_txn *me_txn; /**< current write transaction */
MDB_txn *me_txn0; /**< prealloc'd write transaction */
mdb_size_t me_mapsize; /**< size of the data memory map */
MDB_OFF_T me_size; /**< current file size */
pgno_t me_maxpg; /**< me_mapsize / me_psize */
MDB_dbx *me_dbxs; /**< array of static DB info */
uint16_t *me_dbflags; /**< array of flags from MDB_db.md_flags */
unsigned int *me_dbiseqs; /**< array of dbi sequence numbers */
pthread_key_t me_txkey; /**< thread-key for readers */
txnid_t me_pgoldest; /**< ID of oldest reader last time we looked */
MDB_pgstate me_pgstate; /**< state of old pages from freeDB */
# define me_pglast me_pgstate.mf_pglast
# define me_pghead me_pgstate.mf_pghead
MDB_page *me_dpages; /**< list of malloc'd blocks for re-use */
/** IDL of pages that became unused in a write txn */
MDB_IDL me_free_pgs;
/** ID2L of pages written during a write txn. Length MDB_IDL_UM_SIZE.
* Unused except for a dummy element when #MDB_WRITEMAP.
*/
MDB_ID2L me_dirty_list;
int *me_dirty_nump;
/** Max number of freelist items that can fit in a single overflow page */
int me_maxfree_1pg;
/** Max size of a node on a page */
unsigned int me_nodemax;
#if !(MDB_MAXKEYSIZE)
unsigned int me_maxkey; /**< max size of a key */
#endif
int me_live_reader; /**< have liveness lock in reader table */
#ifdef _WIN32
int me_pidquery; /**< Used in OpenProcess */
OVERLAPPED *me_ov; /**< Used for overlapping I/O requests */
int me_ovs; /**< Count of MDB_overlaps */
#endif
#ifdef MDB_USE_POSIX_MUTEX /* Posix mutexes reside in shared mem */
# define me_rmutex me_txns->mti_rmutex /**< Shared reader lock */
# define me_wmutex me_txns->mti_wmutex /**< Shared writer lock */
#else
mdb_mutex_t me_rmutex;
mdb_mutex_t me_wmutex;
# if defined(_WIN32) || defined(MDB_USE_POSIX_SEM)
/** Half-initialized name of mutexes, to be completed by #MUTEXNAME() */
char me_mutexname[sizeof(MUTEXNAME_PREFIX) + 11];
# endif
#endif
#if MDB_RPAGE_CACHE
MDB_ID3L me_rpages; /**< like #mt_rpages, but global to env */
pthread_mutex_t me_rpmutex; /**< control access to #me_rpages */
MDB_sum_func *me_sumfunc; /**< checksum env data */
unsigned short me_sumsize; /**< size of per-page checksums */
#define MDB_ERPAGE_SIZE 16384
#define MDB_ERPAGE_MAX (MDB_ERPAGE_SIZE-1)
unsigned short me_esumsize; /**< size of per-page authentication data */
unsigned int me_rpcheck;
MDB_enc_func *me_encfunc; /**< encrypt env data */
MDB_val me_enckey; /**< key for env encryption */
#endif
void *me_userctx; /**< User-settable context */
MDB_assert_func *me_assert_func; /**< Callback for assertion failures */
};
/** Nested transaction */
typedef struct MDB_ntxn {
MDB_txn mnt_txn; /**< the transaction */
MDB_pgstate mnt_pgstate; /**< parent transaction's saved freestate */
} MDB_ntxn;
/** max number of pages to commit in one writev() call */
#define MDB_COMMIT_PAGES 64
#if defined(IOV_MAX) && IOV_MAX < MDB_COMMIT_PAGES
#undef MDB_COMMIT_PAGES
#define MDB_COMMIT_PAGES IOV_MAX
#endif
/** max bytes to write in one call */
#define MAX_WRITE (0x40000000U >> (sizeof(ssize_t) == 4))
/** Check \b txn and \b dbi arguments to a function */
#define TXN_DBI_EXIST(txn, dbi, validity) \
((txn) && (dbi)<(txn)->mt_numdbs && ((txn)->mt_dbflags[dbi] & (validity)))
/** Check for misused \b dbi handles */
#define TXN_DBI_CHANGED(txn, dbi) \
((txn)->mt_dbiseqs[dbi] != (txn)->mt_env->me_dbiseqs[dbi])
static int mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp);
static int mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp);
static int mdb_page_touch(MDB_cursor *mc);
#define MDB_END_NAMES {"committed", "empty-commit", "abort", "reset", \
"reset-tmp", "fail-begin", "fail-beginchild"}
enum {
/* mdb_txn_end operation number, for logging */
MDB_END_COMMITTED, MDB_END_EMPTY_COMMIT, MDB_END_ABORT, MDB_END_RESET,
MDB_END_RESET_TMP, MDB_END_FAIL_BEGIN, MDB_END_FAIL_BEGINCHILD
};
#define MDB_END_OPMASK 0x0F /**< mask for #mdb_txn_end() operation number */
#define MDB_END_UPDATE 0x10 /**< update env state (DBIs) */
#define MDB_END_FREE 0x20 /**< free txn unless it is #MDB_env.%me_txn0 */
#define MDB_END_SLOT MDB_NOTLS /**< release any reader slot if #MDB_NOTLS */
static void mdb_txn_end(MDB_txn *txn, unsigned mode);
#if MDB_RPAGE_CACHE
#define MDB_PAGE_GET(mc, pg, numpgs, mp) mdb_page_get(mc, pg, numpgs, mp)
static void mdb_rpage_dispose(MDB_env *env, MDB_ID3 *id3);
#else
/* Drop unused numpgs argument when !MDB_RPAGE_CACHE */
#define MDB_PAGE_GET(mc, pg, numpgs, mp) mdb_page_get(mc, pg, mp)
#endif
static int MDB_PAGE_GET(MDB_cursor *mc, pgno_t pgno, int numpgs, MDB_page **mp);
static int mdb_page_search_root(MDB_cursor *mc,
MDB_val *key, int modify);
#define MDB_PS_MODIFY 1
#define MDB_PS_ROOTONLY 2
#define MDB_PS_FIRST 4
#define MDB_PS_LAST 8
static int mdb_page_search(MDB_cursor *mc,
MDB_val *key, int flags);
static int mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst);
#define MDB_SPLIT_REPLACE MDB_APPENDDUP /**< newkey is not new */
static int mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
pgno_t newpgno, unsigned int nflags);
static int mdb_env_read_header(MDB_env *env, int prev, MDB_meta *meta);
static MDB_meta *mdb_env_pick_meta(const MDB_env *env);
static int mdb_env_write_meta(MDB_txn *txn);
#if defined(MDB_USE_POSIX_MUTEX) && !defined(MDB_ROBUST_SUPPORTED) /* Drop unused excl arg */
# define mdb_env_close_active(env, excl) mdb_env_close1(env)
#endif
static void mdb_env_close_active(MDB_env *env, int excl);
static MDB_node *mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp);
static int mdb_node_add(MDB_cursor *mc, indx_t indx,
MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags);
static void mdb_node_del(MDB_cursor *mc, int ksize);
static void mdb_node_shrink(MDB_page *mp, indx_t indx);
static int mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft);
static int mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data);
static size_t mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data);
static size_t mdb_branch_size(MDB_env *env, MDB_val *key);
static int mdb_rebalance(MDB_cursor *mc);
static int mdb_update_key(MDB_cursor *mc, MDB_val *key);
static void mdb_cursor_pop(MDB_cursor *mc);
static int mdb_cursor_push(MDB_cursor *mc, MDB_page *mp);
static int mdb_cursor_del0(MDB_cursor *mc);
static int mdb_del0(MDB_txn *txn, MDB_dbi dbi, MDB_val *key, MDB_val *data, unsigned flags);
static int mdb_cursor_sibling(MDB_cursor *mc, int move_right);
static int mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
static int mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op);
static int mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op,
int *exactp);
static int mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data);
static int mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data);
static void mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
static void mdb_xcursor_init0(MDB_cursor *mc);
static void mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node);
static void mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int force);
static int mdb_drop0(MDB_cursor *mc, int subs);
static void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
static int mdb_reader_check0(MDB_env *env, int rlocked, int *dead);
/** @cond */
static MDB_cmp_func mdb_cmp_memn, mdb_cmp_memnr, mdb_cmp_int, mdb_cmp_cint, mdb_cmp_long;
/** @endcond */
/** Compare two items pointing at '#mdb_size_t's of unknown alignment. */
#ifdef MISALIGNED_OK
# define mdb_cmp_clong mdb_cmp_long
#else
# define mdb_cmp_clong mdb_cmp_cint
#endif
/** True if we need #mdb_cmp_clong() instead of \b cmp for #MDB_INTEGERDUP */
#define NEED_CMP_CLONG(cmp, ksize) \
(UINT_MAX < MDB_SIZE_MAX && \
(cmp) == mdb_cmp_int && (ksize) == sizeof(mdb_size_t))
#ifdef _WIN32
static SECURITY_DESCRIPTOR mdb_null_sd;
static SECURITY_ATTRIBUTES mdb_all_sa;
static int mdb_sec_inited;
struct MDB_name;
static int utf8_to_utf16(const char *src, struct MDB_name *dst, int xtra);
#endif
/** Return the library version info. */
char * ESECT
mdb_version(int *major, int *minor, int *patch)
{
if (major) *major = MDB_VERSION_MAJOR;
if (minor) *minor = MDB_VERSION_MINOR;
if (patch) *patch = MDB_VERSION_PATCH;
return MDB_VERSION_STRING;
}
/** Table of descriptions for LMDB @ref errors */
static char *const mdb_errstr[] = {
"MDB_KEYEXIST: Key/data pair already exists",
"MDB_NOTFOUND: No matching key/data pair found",
"MDB_PAGE_NOTFOUND: Requested page not found",
"MDB_CORRUPTED: Located page was wrong type",
"MDB_PANIC: Update of meta page failed or environment had fatal error",
"MDB_VERSION_MISMATCH: Database environment version mismatch",
"MDB_INVALID: File is not an LMDB file",
"MDB_MAP_FULL: Environment mapsize limit reached",
"MDB_DBS_FULL: Environment maxdbs limit reached",
"MDB_READERS_FULL: Environment maxreaders limit reached",
"MDB_TLS_FULL: Thread-local storage keys full - too many environments open",
"MDB_TXN_FULL: Transaction has too many dirty pages - transaction too big",
"MDB_CURSOR_FULL: Internal error - cursor stack limit reached",
"MDB_PAGE_FULL: Internal error - page has no more space",
"MDB_MAP_RESIZED: Database contents grew beyond environment mapsize",
"MDB_INCOMPATIBLE: Operation and DB incompatible, or DB flags changed",
"MDB_BAD_RSLOT: Invalid reuse of reader locktable slot",
"MDB_BAD_TXN: Transaction must abort, has a child, or is invalid",
"MDB_BAD_VALSIZE: Unsupported size of key/DB name/data, or wrong DUPFIXED size",
"MDB_BAD_DBI: The specified DBI handle was closed/changed unexpectedly",
"MDB_PROBLEM: Unexpected problem - txn should abort",
"MDB_BAD_CHECKSUM: Page checksum mismatch",
"MDB_CRYPTO_FAIL: Page encryption or decryption failed",
"MDB_ENV_ENCRYPTION: Environment encryption mismatch",
};
char *
mdb_strerror(int err)
{
#ifdef _WIN32
/** HACK: pad 4KB on stack over the buf. Return system msgs in buf.
* This works as long as no function between the call to mdb_strerror
* and the actual use of the message uses more than 4K of stack.
*/
#define MSGSIZE 1024
#define PADSIZE 4096
char buf[MSGSIZE+PADSIZE], *ptr = buf;
#endif
int i;
if (!err)
return ("Successful return: 0");
if (err >= MDB_KEYEXIST && err <= MDB_LAST_ERRCODE) {
i = err - MDB_KEYEXIST;
return mdb_errstr[i];
}
#ifdef _WIN32
/* These are the C-runtime error codes we use. The comment indicates
* their numeric value, and the Win32 error they would correspond to
* if the error actually came from a Win32 API. A major mess, we should
* have used LMDB-specific error codes for everything.
*/
switch(err) {
case ENOENT: /* 2, FILE_NOT_FOUND */
case EIO: /* 5, ACCESS_DENIED */
case ENOMEM: /* 12, INVALID_ACCESS */
case EACCES: /* 13, INVALID_DATA */
case EBUSY: /* 16, CURRENT_DIRECTORY */
case EINVAL: /* 22, BAD_COMMAND */
case ENOSPC: /* 28, OUT_OF_PAPER */
return strerror(err);
default:
;
}
buf[0] = 0;
FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, err, 0, ptr, MSGSIZE, (va_list *)buf+MSGSIZE);
return ptr;
#else
return strerror(err);
#endif
}
/** assert(3) variant in cursor context */
#define mdb_cassert(mc, expr) mdb_assert0((mc)->mc_txn->mt_env, expr, #expr)
/** assert(3) variant in transaction context */
#define mdb_tassert(txn, expr) mdb_assert0((txn)->mt_env, expr, #expr)
/** assert(3) variant in environment context */
#define mdb_eassert(env, expr) mdb_assert0(env, expr, #expr)
#ifndef NDEBUG
# define mdb_assert0(env, expr, expr_txt) ((expr) ? (void)0 : \
mdb_assert_fail(env, expr_txt, mdb_func_, __FILE__, __LINE__))
static void ESECT
mdb_assert_fail(MDB_env *env, const char *expr_txt,
const char *func, const char *file, int line)
{
char buf[400];
sprintf(buf, "%.100s:%d: Assertion '%.200s' failed in %.40s()",
file, line, expr_txt, func);
if (env->me_assert_func)
env->me_assert_func(env, buf);
fprintf(stderr, "%s\n", buf);
abort();
}
#else
# define mdb_assert0(env, expr, expr_txt) ((void) 0)
#endif /* NDEBUG */
#if MDB_DEBUG
/** Return the page number of \b mp which may be sub-page, for debug output */
static pgno_t
mdb_dbg_pgno(MDB_page *mp)
{
pgno_t ret;
COPY_PGNO(ret, mp->mp_pgno);
return ret;
}
/** Display a key in hexadecimal and return the address of the result.
* @param[in] key the key to display
* @param[in] buf the buffer to write into. Should always be #DKBUF.
* @return The key in hexadecimal form.
*/
char *
mdb_dkey(MDB_val *key, char *buf)
{
char *ptr = buf;
unsigned char *c = key->mv_data;
unsigned int i;
if (!key)
return "";
if (key->mv_size > DKBUF_MAXKEYSIZE)
return "MDB_MAXKEYSIZE";
/* may want to make this a dynamic check: if the key is mostly
* printable characters, print it as-is instead of converting to hex.
*/
#if 1
buf[0] = '\0';
for (i=0; i<key->mv_size; i++)
ptr += sprintf(ptr, "%02x", *c++);
#else
sprintf(buf, "%.*s", key->mv_size, key->mv_data);
#endif
return buf;
}
static const char *
mdb_leafnode_type(MDB_node *n)
{
static char *const tp[2][2] = {{"", ": DB"}, {": sub-page", ": sub-DB"}};
return F_ISSET(n->mn_flags, F_BIGDATA) ? ": overflow page" :
tp[F_ISSET(n->mn_flags, F_DUPDATA)][F_ISSET(n->mn_flags, F_SUBDATA)];
}
/** Display all the keys in the page. */
void
mdb_page_list(MDB_page *mp)
{
pgno_t pgno = mdb_dbg_pgno(mp);
const char *type;
MDB_node *node;
unsigned int i, nkeys, nsize, total = 0;
MDB_val key;
DKBUF;
switch (mp->mp_flags & (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP)) {
case P_BRANCH: type = "Branch page"; break;
case P_LEAF: type = "Leaf page"; break;
case P_LEAF|P_SUBP: type = "Sub-page"; break;
case P_LEAF|P_LEAF2: type = "LEAF2 page"; break;
case P_LEAF|P_LEAF2|P_SUBP: type = "LEAF2 sub-page"; break;
case P_OVERFLOW:
fprintf(stderr, "Overflow page %"Yu" pages %u\n", pgno, mp->mp_pages);
return;
case P_META:
fprintf(stderr, "Meta-page %"Yu" txnid %"Yu"\n",
pgno, ((MDB_meta *)METADATA(mp))->mm_txnid);
return;
default:
fprintf(stderr, "Bad page %"Yu" flags 0x%X\n", pgno, mp->mp_flags);
return;
}
nkeys = NUMKEYS(mp);
fprintf(stderr, "%s %"Yu" numkeys %d\n", type, pgno, nkeys);
for (i=0; i<nkeys; i++) {
if (IS_LEAF2(mp)) { /* LEAF2 pages have no mp_ptrs[] or node headers */
key.mv_size = nsize = mp->mp_pad;
key.mv_data = LEAF2KEY(mp, i, nsize);
total += nsize;
fprintf(stderr, "key %d: nsize %d, %s\n", i, nsize, DKEY(&key));
continue;
}
node = NODEPTR(mp, i);
key.mv_size = node->mn_ksize;
key.mv_data = node->mn_data;
nsize = NODESIZE + key.mv_size;
if (IS_BRANCH(mp)) {
fprintf(stderr, "key %d: page %"Yu", %s\n", i, NODEPGNO(node),
DKEY(&key));
total += nsize;
} else {
if (F_ISSET(node->mn_flags, F_BIGDATA))
nsize += sizeof(MDB_ovpage);
else
nsize += NODEDSZ(node);
total += nsize;
nsize += sizeof(indx_t);
fprintf(stderr, "key %d: nsize %d, %s%s\n",
i, nsize, DKEY(&key), mdb_leafnode_type(node));
}
total = EVEN(total);
}
fprintf(stderr, "Total: header %d + contents %d + unused %d\n",
IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + mp->mp_lower, total, SIZELEFT(mp));
}
void
mdb_cursor_chk(MDB_cursor *mc)
{
unsigned int i;
MDB_node *node;
MDB_page *mp;
if (!mc->mc_snum || !(mc->mc_flags & C_INITIALIZED)) return;
for (i=0; i<mc->mc_top; i++) {
mp = mc->mc_pg[i];
node = NODEPTR(mp, mc->mc_ki[i]);
if (NODEPGNO(node) != mc->mc_pg[i+1]->mp_pgno)
printf("oops!\n");
}
if (mc->mc_ki[i] >= NUMKEYS(mc->mc_pg[i]))
printf("ack!\n");
if (XCURSOR_INITED(mc)) {
node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (((node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) &&
mc->mc_xcursor->mx_cursor.mc_pg[0] != NODEDATA(node)) {
printf("blah!\n");
}
}
}
#endif
#if (MDB_DEBUG) > 2
/** Count all the pages in each DB and in the freelist
* and make sure it matches the actual number of pages
* being used.
* All named DBs must be open for a correct count.
*/
static void mdb_audit(MDB_txn *txn)
{
MDB_cursor mc;
MDB_val key, data;
MDB_ID freecount, count;
MDB_dbi i;
int rc;
freecount = 0;
mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
freecount += *(MDB_ID *)data.mv_data;
mdb_tassert(txn, rc == MDB_NOTFOUND);
count = 0;
for (i = 0; i<txn->mt_numdbs; i++) {
MDB_xcursor mx;
if (!(txn->mt_dbflags[i] & DB_VALID))
continue;
mdb_cursor_init(&mc, txn, i, &mx);
if (txn->mt_dbs[i].md_root == P_INVALID)
continue;
count += txn->mt_dbs[i].md_branch_pages +
txn->mt_dbs[i].md_leaf_pages +
txn->mt_dbs[i].md_overflow_pages;
if (txn->mt_dbs[i].md_flags & MDB_DUPSORT) {
rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST);
for (; rc == MDB_SUCCESS; rc = mdb_cursor_sibling(&mc, 1)) {
unsigned j;
MDB_page *mp;
mp = mc.mc_pg[mc.mc_top];
for (j=0; j<NUMKEYS(mp); j++) {
MDB_node *leaf = NODEPTR(mp, j);
if (leaf->mn_flags & F_SUBDATA) {
MDB_db db;
memcpy(&db, NODEDATA(leaf), sizeof(db));
count += db.md_branch_pages + db.md_leaf_pages +
db.md_overflow_pages;
}
}
}
mdb_tassert(txn, rc == MDB_NOTFOUND);
}
}
if (freecount + count + NUM_METAS != txn->mt_next_pgno) {
fprintf(stderr, "audit: %"Yu" freecount: %"Yu" count: %"Yu" total: %"Yu" next_pgno: %"Yu"\n",
txn->mt_txnid, freecount, count+NUM_METAS,
freecount+count+NUM_METAS, txn->mt_next_pgno);
}
}
#endif
int
mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
{
return txn->mt_dbxs[dbi].md_cmp(a, b);
}
int
mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
{
MDB_cmp_func *dcmp = txn->mt_dbxs[dbi].md_dcmp;
if (NEED_CMP_CLONG(dcmp, a->mv_size))
dcmp = mdb_cmp_clong;
return dcmp(a, b);
}
/** Allocate memory for a page.
* Re-use old malloc'd pages first for singletons, otherwise just malloc.
* Set #MDB_TXN_ERROR on failure.
*/
static MDB_page *
mdb_page_malloc(MDB_txn *txn, unsigned num, int init)
{
MDB_env *env = txn->mt_env;
MDB_page *ret = env->me_dpages;
size_t psize = env->me_psize, sz = psize, off;
/* For ! #MDB_NOMEMINIT, psize counts how much to init.
* For a single page alloc, we init everything after the page header.
* For multi-page, we init the final page; if the caller needed that
* many pages they will be filling in at least up to the last page.
*/
if (num == 1) {
psize -= off = PAGEHDRSZ;
if (ret) {
VGMEMP_ALLOC(env, ret, sz);
VGMEMP_DEFINED(ret, sizeof(ret->mp_next));
env->me_dpages = ret->mp_next;
goto init;
}
} else {
sz *= num;
off = sz - psize;
}
if ((ret = malloc(sz)) != NULL) {
VGMEMP_ALLOC(env, ret, sz);
init:
if (init && !(env->me_flags & MDB_NOMEMINIT)) {
memset((char *)ret + off, 0, psize);
ret->mp_pad = 0;
}
} else {
txn->mt_flags |= MDB_TXN_ERROR;
}
ret->mp_flags = 0;
return ret;
}
/** Free a single page.
* Saves single pages to a list, for future reuse.
* (This is not used for multi-page overflow pages.)
*/
static void
mdb_page_free(MDB_env *env, MDB_page *mp)
{
mp->mp_next = env->me_dpages;
VGMEMP_FREE(env, mp);
env->me_dpages = mp;
}
/** Free a dirty page */
static void
mdb_dpage_free(MDB_env *env, MDB_page *dp)
{
if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
mdb_page_free(env, dp);
} else {
/* large pages just get freed directly */
VGMEMP_FREE(env, dp);
free(dp);
}
}
#if MDB_RPAGE_CACHE
/** Free an encrypted dirty page
* We can't check if it's an overflow page,
* caller must tell us how many are being freed.
*/
static void
mdb_dpage_free_n(MDB_env *env, MDB_page *dp, int num)
{
if (num == 1)
mdb_page_free(env, dp);
else {
/* large pages just get freed directly */
VGMEMP_FREE(env, dp);
free(dp);
}
}
#endif
/** Return all dirty pages to dpage list */
static void
mdb_dlist_free(MDB_txn *txn)
{
MDB_env *env = txn->mt_env;
MDB_ID2L dl = txn->mt_u.dirty_list;
unsigned i, n = dl[0].mid;
if (txn->mt_flags & MDB_TXN_DIRTYNUM) {
int *dl_nump = env->me_dirty_nump;
for (i = 1; i <= n; i++) {
mdb_dpage_free_n(env, dl[i].mptr, dl_nump[i]);
}
txn->mt_flags ^= MDB_TXN_DIRTYNUM;
} else {
for (i = 1; i <= n; i++) {
mdb_dpage_free(env, dl[i].mptr);
}
}
dl[0].mid = 0;
}
#if MDB_RPAGE_CACHE
#if defined(MDB_VL32) || ((MDB_RPAGE_CACHE) & 2) /* Always remap */
#define MDB_REMAPPING(flags) 1
#else
#define MDB_REMAPPING(flags) ((flags) & MDB_REMAP_CHUNKS)
#endif
static void
mdb_page_unref(MDB_txn *txn, MDB_page *mp)
{
pgno_t pgno;
MDB_ID3L tl = txn->mt_rpages;
unsigned x, rem;
if (IS_SUBP(mp) || IS_DIRTY_NW(txn, mp))
return;
rem = mp->mp_pgno & (MDB_RPAGE_CHUNK-1);
pgno = mp->mp_pgno ^ rem;
x = mdb_mid3l_search(tl, pgno);
if (x != tl[0].mid && tl[x+1].mid == mp->mp_pgno)
x++;
if (tl[x].mref)
tl[x].mref--;
}
#define MDB_PAGE_UNREF(txn, mp) \
(MDB_REMAPPING(txn->mt_env->me_flags) ? mdb_page_unref(txn, mp) : (void)0)
static void
mdb_cursor_unref(MDB_cursor *mc)
{
int i;
if (mc->mc_txn->mt_rpages[0].mid) {
if (!mc->mc_snum || !mc->mc_pg[0] || IS_SUBP(mc->mc_pg[0]))
return;
for (i=0; i<mc->mc_snum; i++)
mdb_page_unref(mc->mc_txn, mc->mc_pg[i]);
if (mc->mc_ovpg) {
mdb_page_unref(mc->mc_txn, mc->mc_ovpg);
mc->mc_ovpg = 0;
}
}
mc->mc_snum = mc->mc_top = 0;
mc->mc_pg[0] = NULL;
mc->mc_flags &= ~C_INITIALIZED;
}
#define MDB_CURSOR_UNREF(mc, force) \
((MDB_REMAPPING((mc)->mc_txn->mt_env->me_flags) && \
((force) || ((mc)->mc_flags & C_INITIALIZED))) \
? mdb_cursor_unref(mc) \
: (void)0)
/* Unref ovpage \b omp in \b mc and tracked cursors */
static void
mdb_ovpage_unref_all(MDB_cursor *mc, MDB_page *omp)
{
MDB_txn *txn = mc->mc_txn;
MDB_cursor *next = txn->mt_cursors[mc->mc_dbi];
for (;; mc = next, next = mc->mc_next) {
if (MC_OVPG(mc) == omp) {
mdb_page_unref(mc->mc_txn, omp);
MC_SET_OVPG(mc, NULL);
}
if (next == NULL)
break;
}
}
#else
#define MDB_REMAPPING(flags) 0
#define MDB_PAGE_UNREF(txn, mp)
#define MDB_CURSOR_UNREF(mc, force) ((void)0)
#define mdb_ovpage_unref_all(mc, omp, pgno) ((void)0)
#endif /* MDB_RPAGE_CACHE */
/** Loosen or free a single page.
* Saves single pages to a list for future reuse
* in this same txn. It has been pulled from the freeDB
* and already resides on the dirty list, but has been
* deleted. Use these pages first before pulling again
* from the freeDB.
*
* If the page wasn't dirtied in this txn, just add it
* to this txn's free list.
*/
static int
mdb_page_loose(MDB_cursor *mc, MDB_page *mp)
{
int rc = MDB_SUCCESS;
MDB_txn *txn = mc->mc_txn;
if (IS_WRITABLE(txn, mp) && mc->mc_dbi != FREE_DBI) {
/* Page is dirty in this txn, and is not in freeDB */
DPRINTF(("loosen db %d page %"Yu, DDBI(mc), mp->mp_pgno));
NEXT_LOOSE_PAGE(mp) = txn->mt_loose_pgs;
txn->mt_loose_pgs = mp;
txn->mt_loose_count++;
mp->mp_flags |= P_LOOSE;
} else {
rc = mdb_midl_append(&txn->mt_free_pgs, mp->mp_pgno);
}
return rc;
}
/** Set or clear P_KEEP in dirty, non-overflow, non-sub pages watched by txn.
* @param[in] mc A cursor handle for the current operation.
* @param[in] pflags Flags of the pages to update:
* 0 to set P_KEEP, P_KEEP to clear it.
* @param[in] all No shortcuts. Needed except after a full #mdb_page_flush().
* @return 0 on success, non-zero on failure.
*/
static int
mdb_pages_xkeep(MDB_cursor *mc, unsigned pflags, int all)
{
enum { Mask = P_SUBP|P_LOOSE|P_KEEP };
MDB_txn *txn = mc->mc_txn;
MDB_cursor *m3, *m0 = mc;
MDB_xcursor *mx;
MDB_page *dp, *mp;
MDB_node *leaf;
unsigned i, j, x;
int rc = MDB_SUCCESS;
/* Mark pages seen by cursors: First m0, then tracked cursors */
for (i = txn->mt_numdbs;; ) {
if (mc->mc_flags & C_INITIALIZED) {
for (m3 = mc;; m3 = &mx->mx_cursor) {
mp = NULL;
for (j=0; j<m3->mc_snum; j++) {
mp = m3->mc_pg[j];
if ((mp->mp_flags & Mask) == pflags)
if (IS_WRITABLE(txn, mp))
mp->mp_flags ^= P_KEEP;
}
if (MC_OVPG(m3) && ((MC_OVPG(m3)->mp_flags & Mask) == pflags) &&
IS_WRITABLE(txn, MC_OVPG(m3)))
MC_OVPG(m3)->mp_flags ^= P_KEEP;
mx = m3->mc_xcursor;
/* Proceed to mx if it is at a sub-database */
if (! (mx && (mx->mx_cursor.mc_flags & C_INITIALIZED)))
break;
if (! (mp && (mp->mp_flags & P_LEAF)))
break;
leaf = NODEPTR(mp, m3->mc_ki[j-1]);
if (!(leaf->mn_flags & F_SUBDATA))
break;
}
}
mc = mc->mc_next;
for (; !mc || mc == m0; mc = txn->mt_cursors[--i])
if (i == 0)
goto mark_done;
}
mark_done:
if (all) {
/* Mark dirty root pages */
MDB_ID2L dl = txn->mt_u.dirty_list;
for (i=0; i<txn->mt_numdbs; i++) {
if (txn->mt_dbflags[i] & DB_DIRTY) {
pgno_t pgno = txn->mt_dbs[i].md_root;
if (pgno == P_INVALID)
continue;
x = mdb_mid2l_search(dl, pgno);
if (! (x <= dl[0].mid && dl[x].mid == pgno))
continue;
dp = dl[x].mptr;
if ((dp->mp_flags & Mask) == pflags)
dp->mp_flags ^= P_KEEP;
}
}
}
return rc;
}
static int mdb_page_flush(MDB_txn *txn, int keep);
/** Spill pages from the dirty list back to disk.
* This is intended to prevent running into #MDB_TXN_FULL situations,
* but note that they may still occur in a few cases:
* 1) our estimate of the txn size could be too small. Currently this
* seems unlikely, except with a large number of #MDB_MULTIPLE items.
* 2) child txns may run out of space if their parents dirtied a
* lot of pages and never spilled them. TODO: we probably should do
* a preemptive spill during #mdb_txn_begin() of a child txn, if
* the parent's dirty_room is below a given threshold.
*
* Otherwise, if not using nested txns, it is expected that apps will
* not run into #MDB_TXN_FULL any more. The pages are flushed to disk
* the same way as for a txn commit.
* If the txn never references them again, they can be left alone.
* If the txn only reads them, they can be used without any fuss.
* If the txn writes them again, they can be dirtied immediately without
* going thru all of the work of #mdb_page_touch(). Such references are
* handled by #mdb_page_unspill().
*
* Also note, we never spill DB root pages, nor pages of active cursors,
* because we'll need these back again soon anyway. And in nested txns,
* we can't spill a page in a child txn if it was already spilled in a
* parent txn. That would alter the parent txns' data even though
* the child hasn't committed yet, and we'd have no way to undo it if
* the child aborted.
*
* @param[in] m0 cursor A cursor handle identifying the transaction and
* database for which we are checking space.
* @param[in] key For a put operation, the key being stored.
* @param[in] data For a put operation, the data being stored.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_spill(MDB_cursor *m0, MDB_val *key, MDB_val *data)
{
MDB_txn *txn = m0->mc_txn;
MDB_page *dp;
MDB_ID2L dl = txn->mt_u.dirty_list;
unsigned int i, j, need;
int rc;
if (m0->mc_flags & (C_SUB|C_WRITEMAP))
return MDB_SUCCESS;
/* Estimate how much space this op will take */
i = m0->mc_db->md_depth;
/* Named DBs also dirty the main DB */
if (m0->mc_dbi >= CORE_DBS)
i += txn->mt_dbs[MAIN_DBI].md_depth;
/* For puts, roughly factor in the key+data size */
if (key)
i += (LEAFSIZE(key, data) + txn->mt_env->me_psize) / txn->mt_env->me_psize;
i += i; /* double it for good measure */
need = i;
if (txn->mt_dirty_room > i)
return MDB_SUCCESS;
if (!txn->mt_spill_pgs) {
txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);
if (!txn->mt_spill_pgs)
return ENOMEM;
} else {
/* purge deleted slots */
MDB_IDL sl = txn->mt_spill_pgs;
unsigned int num = sl[0];
j=0;
for (i=1; i<=num; i++) {
if (!(sl[i] & 1))
sl[++j] = sl[i];
}
sl[0] = j;
}
/* Preserve pages which may soon be dirtied again */
if ((rc = mdb_pages_xkeep(m0, 0, 1)) != MDB_SUCCESS)
goto done;
/* Less aggressive spill - we originally spilled the entire dirty list,
* with a few exceptions for cursor pages and DB root pages. But this
* turns out to be a lot of wasted effort because in a large txn many
* of those pages will need to be used again. So now we spill only 1/8th
* of the dirty pages. Testing revealed this to be a good tradeoff,
* better than 1/2, 1/4, or 1/10.
*/
if (need < MDB_IDL_UM_MAX / 8)
need = MDB_IDL_UM_MAX / 8;
/* Save the page IDs of all the pages we're flushing */
/* flush from the tail forward, this saves a lot of shifting later on. */
for (i=dl[0].mid; i && need; i--) {
MDB_ID pn = dl[i].mid << 1;
dp = dl[i].mptr;
if (dp->mp_flags & (P_LOOSE|P_KEEP))
continue;
/* Can't spill twice, make sure it's not already in a parent's
* spill list.
*/
if (txn->mt_parent) {
MDB_txn *tx2;
for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
if (tx2->mt_spill_pgs) {
j = mdb_midl_search(tx2->mt_spill_pgs, pn);
if (j <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[j] == pn) {
dp->mp_flags |= P_KEEP;
break;
}
}
}
if (tx2)
continue;
}
if ((rc = mdb_midl_append(&txn->mt_spill_pgs, pn)))
goto done;
need--;
}
mdb_midl_sort(txn->mt_spill_pgs);
/* Flush the spilled part of dirty list */
if ((rc = mdb_page_flush(txn, i)) != MDB_SUCCESS)
goto done;
/* Reset any dirty pages we kept that page_flush didn't see */
rc = mdb_pages_xkeep(m0, P_KEEP, i);
done:
txn->mt_flags |= rc ? MDB_TXN_ERROR : MDB_TXN_SPILLS;
return rc;
}
/** Find oldest txnid still referenced. Expects txn->mt_txnid > 0. */
static txnid_t
mdb_find_oldest(MDB_txn *txn)
{
int i;
txnid_t mr, oldest = txn->mt_txnid - 1;
if (txn->mt_env->me_txns) {
MDB_reader *r = txn->mt_env->me_txns->mti_readers;
for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
if (r[i].mr_pid) {
mr = r[i].mr_txnid;
if (oldest > mr)
oldest = mr;
}
}
}
return oldest;
}
/** Add a page to the txn's dirty list, if there is one */
static void
mdb_page_dirty(MDB_txn *txn, MDB_page *mp)
{
MDB_ID2 mid;
int rc;
if (txn->mt_flags & MDB_TXN_WRITEMAP) {
txn->mt_flags |= MDB_TXN_DIRTY;
return;
}
mid.mid = mp->mp_pgno;
mid.mptr = mp;
rc = mdb_mid2l_insert(txn->mt_u.dirty_list, &mid);
mdb_tassert(txn, rc == 0);
txn->mt_dirty_room--;
}
/** Allocate page numbers and memory for writing. Maintain me_pglast,
* me_pghead and mt_next_pgno. Set #MDB_TXN_ERROR on failure.
*
* If there are free pages available from older transactions, they
* are re-used first. Otherwise allocate a new page at mt_next_pgno.
* Do not modify the freedB, just merge freeDB records into me_pghead[]
* and move me_pglast to say which records were consumed. Only this
* function can create me_pghead and move me_pglast/mt_next_pgno.
* When #MDB_DEVEL & 2, it is not affected by #mdb_freelist_save(): it
* then uses the transaction's original snapshot of the freeDB.
* @param[in] mc cursor A cursor handle identifying the transaction and
* database for which we are allocating.
* @param[in] num the number of pages to allocate.
* @param[out] mp Address of the allocated page(s). Requests for multiple pages
* will always be satisfied by a single contiguous chunk of memory.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
{
#ifdef MDB_PARANOID /* Seems like we can ignore this now */
/* Get at most <Max_retries> more freeDB records once me_pghead
* has enough pages. If not enough, use new pages from the map.
* If <Paranoid> and mc is updating the freeDB, only get new
* records if me_pghead is empty. Then the freelist cannot play
* catch-up with itself by growing while trying to save it.
*/
enum { Paranoid = 1, Max_retries = 500 };
#else
enum { Paranoid = 0, Max_retries = INT_MAX /*infinite*/ };
#endif
int rc, retry = num * 60;
MDB_txn *txn = mc->mc_txn;
MDB_env *env = txn->mt_env;
pgno_t pgno, *mop = env->me_pghead;
unsigned i, j, mop_len = mop ? mop[0] : 0, n2 = num-1;
MDB_page *np;
txnid_t oldest = 0, last;
MDB_cursor_op op;
MDB_cursor m2;
int found_old = 0;
#if OVERFLOW_NOTYET
MDB_dovpage *dph = NULL;
if (ov) {
if (!txn->mt_dirty_ovs) {
txn->mt_dirty_ovs = mdb_mid2l_alloc(16);
if (!txn->mt_dirty_ovs)
return ENOMEM;
} else if (mdb_mid2l_need(&txn->mt_dirty_ovs, txn->mt_dirty_ovs[0].mid + 1))
return ENOMEM;
dph = malloc(sizeof(MDB_dovpage));
}
#endif
/* If there are any loose pages, just use them */
if (num == 1 && txn->mt_loose_pgs) {
np = txn->mt_loose_pgs;
txn->mt_loose_pgs = NEXT_LOOSE_PAGE(np);
txn->mt_loose_count--;
DPRINTF(("db %d use loose page %"Yu, DDBI(mc), np->mp_pgno));
#if OVERFLOW_NOTYET
if (ov) {
dph->mp_hdr = np->mp_hdr;
dph->mp_ptr = np;
np = (MDB_page *)dph;
}
#endif
*mp = np;
np->mp_flags &= P_ADM_FLAGS;
return MDB_SUCCESS;
}
*mp = NULL;
/* If our dirty list is already full, we can't do anything */
if (txn->mt_dirty_room == 0) {
rc = MDB_TXN_FULL;
goto fail;
}
for (op = MDB_FIRST;; op = MDB_NEXT) {
MDB_val key, data;
MDB_node *leaf;
pgno_t *idl;
/* Seek a big enough contiguous page range. Prefer
* pages at the tail, just truncating the list.
*/
if (mop_len > n2) {
i = mop_len;
do {
pgno = mop[i];
if (mop[i-n2] == pgno+n2)
goto search_done;
} while (--i > n2);
if (--retry < 0)
break;
}
if (op == MDB_FIRST) { /* 1st iteration */
/* Prepare to fetch more and coalesce */
last = env->me_pglast;
oldest = env->me_pgoldest;
mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
#if (MDB_DEVEL) & 2 /* "& 2" so MDB_DEVEL=1 won't hide bugs breaking freeDB */
/* Use original snapshot. TODO: Should need less care in code
* which modifies the database. Maybe we can delete some code?
*/
m2.mc_flags |= C_ORIG_RDONLY;
m2.mc_db = &env->me_metas[(txn->mt_txnid-1) & 1]->mm_dbs[FREE_DBI];
m2.mc_dbflag = (unsigned char *)""; /* probably unnecessary */
#endif
if (last) {
op = MDB_SET_RANGE;
key.mv_data = &last; /* will look up last+1 */
key.mv_size = sizeof(last);
}
if (Paranoid && mc->mc_dbi == FREE_DBI)
retry = -1;
}
if (Paranoid && retry < 0 && mop_len)
break;
last++;
/* Do not fetch more if the record will be too recent */
if (oldest <= last) {
if (!found_old) {
oldest = mdb_find_oldest(txn);
env->me_pgoldest = oldest;
found_old = 1;
}
if (oldest <= last)
break;
}
rc = mdb_cursor_get(&m2, &key, NULL, op);
if (rc) {
if (rc == MDB_NOTFOUND)
break;
goto fail;
}
last = *(txnid_t*)key.mv_data;
if (oldest <= last) {
if (!found_old) {
oldest = mdb_find_oldest(txn);
env->me_pgoldest = oldest;
found_old = 1;
}
if (oldest <= last)
break;
}
np = m2.mc_pg[m2.mc_top];
leaf = NODEPTR(np, m2.mc_ki[m2.mc_top]);
if ((rc = mdb_node_read(&m2, leaf, &data)) != MDB_SUCCESS)
goto fail;
idl = (MDB_ID *) data.mv_data;
i = idl[0];
if (!mop) {
if (!(env->me_pghead = mop = mdb_midl_alloc(i))) {
rc = ENOMEM;
goto fail;
}
} else {
if ((rc = mdb_midl_need(&env->me_pghead, i)) != 0)
goto fail;
mop = env->me_pghead;
}
env->me_pglast = last;
#if (MDB_DEBUG) > 1
DPRINTF(("IDL read txn %"Yu" root %"Yu" num %u",
last, txn->mt_dbs[FREE_DBI].md_root, i));
for (j = i; j; j--)
DPRINTF(("IDL %"Yu, idl[j]));
#endif
/* Merge in descending sorted order */
mdb_midl_xmerge(mop, idl);
mop_len = mop[0];
}
/* Use new pages from the map when nothing suitable in the freeDB */
i = 0;
pgno = txn->mt_next_pgno;
if (pgno + num >= env->me_maxpg) {
DPUTS("DB size maxed out");
rc = MDB_MAP_FULL;
goto fail;
}
#if defined(_WIN32)
if (!MDB_REMAPPING(env->me_flags) && !(env->me_flags & MDB_RDONLY)) {
void *p;
p = (MDB_page *)(env->me_map + env->me_psize * pgno);
p = VirtualAlloc(p, env->me_psize * num, MEM_COMMIT,
(env->me_flags & MDB_WRITEMAP) ? PAGE_READWRITE:
PAGE_READONLY);
if (!p) {
DPUTS("VirtualAlloc failed");
rc = ErrCode();
goto fail;
}
}
#endif
search_done:
if (env->me_flags & MDB_WRITEMAP) {
np = (MDB_page *)(env->me_map + env->me_psize * pgno);
} else {
if (!(np = mdb_page_malloc(txn, num, 1))) {
rc = ENOMEM;
goto fail;
}
}
if (i) {
mop[0] = mop_len -= num;
/* Move any stragglers down */
for (j = i-num; j < mop_len; )
mop[++j] = mop[++i];
} else {
txn->mt_next_pgno = pgno + num;
}
#if OVERFLOW_NOTYET
if (ov) {
dph->mp_hdr = np->mp_hdr;
dph->mp_ptr = np;
np = (MDB_page *)dph;
}
#endif
np->mp_pgno = pgno;
SET_PGTXNID(txn, np);
np->mp_flags = 0;
#if OVERFLOW_NOTYET
mdb_page_dirty(txn, np, ov);
#else
mdb_page_dirty(txn, np);
#endif
*mp = np;
return MDB_SUCCESS;
fail:
#if OVERFLOW_NOTYET
if (dph)
free(dph);
#endif
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
/** Copy the used portions of a non-overflow page.
* @param[in] dst page to copy into
* @param[in] src page to copy from
* @param[in] psize size of a page
*/
static void
mdb_page_copy(MDB_page *dst, MDB_page *src, unsigned int psize)
{
enum { Align = sizeof(pgno_t) };
indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper-lower;
/* If page isn't full, just copy the used portion. Adjust
* alignment so memcpy may copy words instead of bytes.
*/
if ((unused &= -Align) && !IS_LEAF2(src)) {
upper = (upper + PAGEBASE) & -Align;
memcpy(dst, src, (lower + PAGEBASE + (Align-1)) & -Align);
memcpy((pgno_t *)((char *)dst+upper), (pgno_t *)((char *)src+upper),
psize - upper);
} else {
memcpy(dst, src, psize - unused);
}
}
/** Bring back a page which this txn spilled to disk; make it writable again.
* @param[in] txn the transaction handle.
* @param[in] mp the spilled page.
* @param[out] ret the writable page.
*/
static int
mdb_page_unspill(MDB_txn *txn, MDB_page *mp, MDB_page **ret)
{
MDB_env *env = txn->mt_env;
unsigned x;
pgno_t pgno = mp->mp_pgno, pn = pgno << 1;
if (txn->mt_dirty_room == 0)
return MDB_TXN_FULL;
/* x = position in current spill list, or 0 */
x = 0;
if (txn->mt_spill_pgs) {
x = mdb_midl_search(txn->mt_spill_pgs, pn);
if (! (x <= txn->mt_spill_pgs[0] && txn->mt_spill_pgs[x] == pn))
x = 0;
}
if (x == 0 && !txn->mt_parent)
return MDB_PROBLEM; /* should be a spilled page */
{
MDB_page *np;
int num;
if (IS_OVERFLOW(mp))
num = mp->mp_pages;
else
num = 1;
{
np = mdb_page_malloc(txn, num, 1);
if (!np)
return ENOMEM;
if (num > 1)
memcpy(np, mp, num * env->me_psize);
else
mdb_page_copy(np, mp, env->me_psize);
}
if (x) {
/* If in current txn, this page is no longer spilled.
* If it happens to be the last page, truncate the spill list.
* Otherwise mark it as deleted by setting the LSB.
*/
if (x == txn->mt_spill_pgs[0])
txn->mt_spill_pgs[0]--;
else
txn->mt_spill_pgs[x] |= 1;
} /* otherwise, if belonging to a parent txn, the
* page remains spilled until child commits
*/
mdb_page_dirty(txn, np);
SET_PGTXNID(txn, np);
*ret = np;
return MDB_SUCCESS;
}
}
/** Touch a page: make it dirty and re-insert into tree with updated pgno.
* Set #MDB_TXN_ERROR on failure.
* @param[in] mc cursor pointing to the page to be touched
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_touch(MDB_cursor *mc)
{
MDB_page *mp = mc->mc_pg[mc->mc_top], *np;
MDB_txn *txn = mc->mc_txn;
MDB_cursor *m2, *m3;
unsigned np_flags;
pgno_t pgno;
int rc;
if (IS_SUBP(mp) || IS_WRITABLE(txn, mp))
return MDB_SUCCESS;
if (!IS_MUTABLE(txn, mp)) {
/* Page from an older snapshot */
if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||
(rc = mdb_page_alloc(mc, 1, &np)))
goto fail;
pgno = np->mp_pgno;
DPRINTF(("touched db %d page %"Yu" -> %"Yu, DDBI(mc),
mp->mp_pgno, pgno));
mdb_cassert(mc, mp->mp_pgno != pgno);
mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
/* Update the parent page, if any, to point to the new page */
if (mc->mc_top) {
MDB_page *parent = mc->mc_pg[mc->mc_top-1];
MDB_node *node = NODEPTR(parent, mc->mc_ki[mc->mc_top-1]);
SETPGNO(node, pgno);
} else {
mc->mc_db->md_root = pgno;
}
} else if (!IS_DIRTY_NW(txn, mp)) {
rc = mdb_page_unspill(txn, mp, &np);
if (rc)
goto fail;
goto done;
} else {
/* Writable in an ancestor txn */
MDB_ID2 mid, *dl = txn->mt_u.dirty_list;
pgno = mp->mp_pgno;
if (!txn->mt_parent) {
rc = MDB_PROBLEM;
goto fail;
}
mdb_cassert(mc, dl[0].mid < MDB_IDL_UM_MAX);
np = mdb_page_malloc(txn, 1, 1);
if (!np) {
rc = ENOMEM;
goto fail;
}
mid.mid = pgno;
mid.mptr = np;
rc = mdb_mid2l_insert(dl, &mid);
mdb_cassert(mc, rc == 0);
}
np_flags = np->mp_flags; /* P_ADM_FLAGS */
mdb_page_copy(np, mp, txn->mt_env->me_psize);
np->mp_flags |= np_flags;
np->mp_pgno = pgno;
SET_PGTXNID(txn, np);
done:
/* Adjust cursors pointing to mp */
mc->mc_pg[mc->mc_top] = np;
m2 = txn->mt_cursors[mc->mc_dbi];
if (mc->mc_flags & C_SUB) {
for (; m2; m2=m2->mc_next) {
m3 = &m2->mc_xcursor->mx_cursor;
if (m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[mc->mc_top] == mp)
m3->mc_pg[mc->mc_top] = np;
}
} else {
for (; m2; m2=m2->mc_next) {
if (m2->mc_snum < mc->mc_snum) continue;
if (m2 == mc) continue;
if (m2->mc_pg[mc->mc_top] == mp) {
m2->mc_pg[mc->mc_top] = np;
if (IS_LEAF(np))
XCURSOR_REFRESH(m2, mc->mc_top, np);
}
}
}
MDB_PAGE_UNREF(mc->mc_txn, mp);
return 0;
fail:
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
int
mdb_env_sync0(MDB_env *env, int force, pgno_t numpgs)
{
int rc = 0;
if (env->me_flags & MDB_RDONLY)
return EACCES;
if (force
#ifndef _WIN32 /* Sync is normally achieved in Windows by doing WRITE_THROUGH writes */
|| !(env->me_flags & MDB_NOSYNC)
#endif
) {
if (env->me_flags & MDB_WRITEMAP) {
int flags = ((env->me_flags & MDB_MAPASYNC) && !force)
? MS_ASYNC : MS_SYNC;
if (MDB_MSYNC(env->me_map, env->me_psize * numpgs, flags))
rc = ErrCode();
#ifdef _WIN32
else if (flags == MS_SYNC && MDB_FDATASYNC(env->me_fd))
rc = ErrCode();
#endif
} else {
#ifdef BROKEN_FDATASYNC
if (env->me_flags & MDB_FSYNCONLY) {
if (fsync(env->me_fd))
rc = ErrCode();
} else
#endif
if (MDB_FDATASYNC(env->me_fd))
rc = ErrCode();
}
}
return rc;
}
int
mdb_env_sync(MDB_env *env, int force)
{
MDB_meta *m = mdb_env_pick_meta(env);
return mdb_env_sync0(env, force, m->mm_last_pg+1);
}
/** Back up parent txn's cursors, then grab the originals for tracking */
static int
mdb_cursor_shadow(MDB_txn *src, MDB_txn *dst)
{
MDB_cursor *mc, *bk;
MDB_xcursor *mx;
size_t size;
int i;
for (i = src->mt_numdbs; --i >= 0; ) {
if ((mc = src->mt_cursors[i]) != NULL) {
size = sizeof(MDB_cursor);
if (mc->mc_xcursor)
size += sizeof(MDB_xcursor);
for (; mc; mc = bk->mc_next) {
bk = malloc(size);
if (!bk)
return ENOMEM;
*bk = *mc;
mc->mc_backup = bk;
mc->mc_db = &dst->mt_dbs[i];
/* Kill pointers into src to reduce abuse: The
* user may not use mc until dst ends. But we need a valid
* txn pointer here for cursor fixups to keep working.
*/
mc->mc_txn = dst;
mc->mc_dbflag = &dst->mt_dbflags[i];
if ((mx = mc->mc_xcursor) != NULL) {
*(MDB_xcursor *)(bk+1) = *mx;
mx->mx_cursor.mc_txn = dst;
}
mc->mc_next = dst->mt_cursors[i];
dst->mt_cursors[i] = mc;
}
}
}
return MDB_SUCCESS;
}
/** Close this write txn's cursors, give parent txn's cursors back to parent.
* @param[in] txn the transaction handle.
* @param[in] merge true to keep changes to parent cursors, false to revert.
* @return 0 on success, non-zero on failure.
*/
static void
mdb_cursors_close(MDB_txn *txn, unsigned merge)
{
MDB_cursor **cursors = txn->mt_cursors, *mc, *next, *bk;
MDB_xcursor *mx;
int i;
for (i = txn->mt_numdbs; --i >= 0; ) {
for (mc = cursors[i]; mc; mc = next) {
next = mc->mc_next;
if ((bk = mc->mc_backup) != NULL) {
if (merge) {
/* Commit changes to parent txn */
mc->mc_next = bk->mc_next;
mc->mc_backup = bk->mc_backup;
mc->mc_txn = bk->mc_txn;
mc->mc_db = bk->mc_db;
mc->mc_dbflag = bk->mc_dbflag;
if ((mx = mc->mc_xcursor) != NULL)
mx->mx_cursor.mc_txn = bk->mc_txn;
} else {
/* Abort nested txn */
*mc = *bk;
if ((mx = mc->mc_xcursor) != NULL)
*mx = *(MDB_xcursor *)(bk+1);
}
mc = bk;
}
/* Only malloced cursors are permanently tracked. */
free(mc);
}
cursors[i] = NULL;
}
}
#if !(MDB_PIDLOCK) /* Currently the same as defined(_WIN32) */
enum Pidlock_op {
Pidset, Pidcheck
};
#else
enum Pidlock_op {
Pidset = F_SETLK, Pidcheck = F_GETLK
};
#endif
/** Set or check a pid lock. Set returns 0 on success.
* Check returns 0 if the process is certainly dead, nonzero if it may
* be alive (the lock exists or an error happened so we do not know).
*
* On Windows Pidset is a no-op, we merely check for the existence
* of the process with the given pid. On POSIX we use a single byte
* lock on the lockfile, set at an offset equal to the pid.
*/
static int
mdb_reader_pid(MDB_env *env, enum Pidlock_op op, MDB_PID_T pid)
{
#if !(MDB_PIDLOCK) /* Currently the same as defined(_WIN32) */
int ret = 0;
HANDLE h;
if (op == Pidcheck) {
h = OpenProcess(env->me_pidquery, FALSE, pid);
/* No documented "no such process" code, but other program use this: */
if (!h)
return ErrCode() != ERROR_INVALID_PARAMETER;
/* A process exists until all handles to it close. Has it exited? */
ret = WaitForSingleObject(h, 0) != 0;
CloseHandle(h);
}
return ret;
#else
for (;;) {
int rc;
struct flock lock_info;
memset(&lock_info, 0, sizeof(lock_info));
lock_info.l_type = F_WRLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = pid;
lock_info.l_len = 1;
if ((rc = fcntl(env->me_lfd, op, &lock_info)) == 0) {
if (op == F_GETLK && lock_info.l_type != F_UNLCK)
rc = -1;
} else if ((rc = ErrCode()) == EINTR) {
continue;
}
return rc;
}
#endif
}
/** Common code for #mdb_txn_begin() and #mdb_txn_renew().
* @param[in] txn the transaction handle to initialize
* @return 0 on success, non-zero on failure.
*/
static int
mdb_txn_renew0(MDB_txn *txn)
{
MDB_env *env = txn->mt_env;
MDB_txninfo *ti = env->me_txns;
MDB_meta *meta;
unsigned int i, nr, flags = txn->mt_flags;
uint16_t x;
int rc, new_notls = 0;
if ((flags &= MDB_TXN_RDONLY) != 0) {
if (!ti) {
meta = mdb_env_pick_meta(env);
txn->mt_txnid = meta->mm_txnid;
txn->mt_u.reader = NULL;
} else {
MDB_reader *r = (env->me_flags & MDB_NOTLS) ? txn->mt_u.reader :
pthread_getspecific(env->me_txkey);
if (r) {
if (r->mr_pid != env->me_pid || r->mr_txnid != (txnid_t)-1)
return MDB_BAD_RSLOT;
} else {
MDB_PID_T pid = env->me_pid;
MDB_THR_T tid = pthread_self();
mdb_mutexref_t rmutex = env->me_rmutex;
if (!env->me_live_reader) {
rc = mdb_reader_pid(env, Pidset, pid);
if (rc)
return rc;
env->me_live_reader = 1;
}
if (LOCK_MUTEX(rc, env, rmutex))
return rc;
nr = ti->mti_numreaders;
for (i=0; i<nr; i++)
if (ti->mti_readers[i].mr_pid == 0)
break;
if (i == env->me_maxreaders) {
UNLOCK_MUTEX(rmutex);
return MDB_READERS_FULL;
}
r = &ti->mti_readers[i];
/* Claim the reader slot, carefully since other code
* uses the reader table un-mutexed: First reset the
* slot, next publish it in mti_numreaders. After
* that, it is safe for mdb_env_close() to touch it.
* When it will be closed, we can finally claim it.
*/
r->mr_pid = 0;
r->mr_txnid = (txnid_t)-1;
r->mr_tid = tid;
if (i == nr)
ti->mti_numreaders = ++nr;
env->me_close_readers = nr;
r->mr_pid = pid;
UNLOCK_MUTEX(rmutex);
new_notls = (env->me_flags & MDB_NOTLS);
if (!new_notls && (rc=pthread_setspecific(env->me_txkey, r))) {
r->mr_pid = 0;
return rc;
}
}
do /* LY: Retry on a race, ITS#7970. */
r->mr_txnid = ti->mti_txnid;
while(r->mr_txnid != ti->mti_txnid);
txn->mt_txnid = r->mr_txnid;
txn->mt_u.reader = r;
meta = env->me_metas[txn->mt_txnid & 1];
}
} else {
/* Not yet touching txn == env->me_txn0, it may be active */
if (ti) {
if (LOCK_MUTEX(rc, env, env->me_wmutex))
return rc;
txn->mt_txnid = ti->mti_txnid;
meta = env->me_metas[txn->mt_txnid & 1];
} else {
meta = mdb_env_pick_meta(env);
txn->mt_txnid = meta->mm_txnid;
}
txn->mt_txnid++;
#if MDB_DEBUG
if (txn->mt_txnid == mdb_debug_start)
mdb_debug = 1;
#endif
txn->mt_child = NULL;
txn->mt_loose_pgs = NULL;
txn->mt_loose_count = 0;
if (env->me_flags & MDB_WRITEMAP) {
txn->mt_workid = txn->mt_txnid;
txn->mt_dirty_room = 1;
} else {
txn->mt_workid = (txn->mt_txnid | MDB_PGTXNID_FLAGMASK) + 1;
txn->mt_dirty_room = MDB_IDL_UM_MAX;
}
txn->mt_last_workid = txn->mt_workid;
txn->mt_u.dirty_list = env->me_dirty_list;
txn->mt_u.dirty_list[0].mid = 0;
txn->mt_free_pgs = env->me_free_pgs;
txn->mt_free_pgs[0] = 0;
txn->mt_spill_pgs = NULL;
#if OVERFLOW_NOTYET
txn->mt_dirty_ovs = NULL;
#endif
env->me_txn = txn;
memcpy(txn->mt_dbiseqs, env->me_dbiseqs, env->me_maxdbs * sizeof(unsigned int));
}
/* Copy the DB info and flags */
memcpy(txn->mt_dbs, meta->mm_dbs, CORE_DBS * sizeof(MDB_db));
/* Moved to here to avoid a data race in read TXNs */
txn->mt_next_pgno = meta->mm_last_pg+1;
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags))
txn->mt_last_pgno = txn->mt_next_pgno - 1;
#endif
txn->mt_flags = flags;
/* Setup db info */
txn->mt_numdbs = env->me_numdbs;
for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
x = env->me_dbflags[i];
txn->mt_dbs[i].md_flags = x & PERSISTENT_FLAGS;
txn->mt_dbflags[i] = (x & MDB_VALID) ? DB_VALID|DB_USRVALID|DB_STALE : 0;
}
txn->mt_dbflags[MAIN_DBI] = DB_VALID|DB_USRVALID;
txn->mt_dbflags[FREE_DBI] = DB_VALID;
if (env->me_flags & MDB_FATAL_ERROR) {
DPUTS("environment had fatal error, must shutdown!");
rc = MDB_PANIC;
} else if (env->me_maxpg < txn->mt_next_pgno) {
rc = MDB_MAP_RESIZED;
} else {
return MDB_SUCCESS;
}
mdb_txn_end(txn, new_notls /*0 or MDB_END_SLOT*/ | MDB_END_FAIL_BEGIN);
return rc;
}
int
mdb_txn_renew(MDB_txn *txn)
{
int rc;
if (!txn || !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY|MDB_TXN_FINISHED))
return EINVAL;
rc = mdb_txn_renew0(txn);
if (rc == MDB_SUCCESS) {
DPRINTF(("renew txn %"Yu"%c %p on mdbenv %p, root page %"Yu,
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root));
}
return rc;
}
/** Used up all workids. Rewind it and update dirty pages to match. */
static txnid_t ESECT
mdb_workid_rewind(MDB_txn *txn)
{
txnid_t workid, diff;
while (txn->mt_parent)
txn = txn->mt_parent;
workid = txn->mt_txnid & ~MDB_PGTXNID_FLAGMASK;
do {
workid += MDB_PGTXNID_STEP;
diff = txn->mt_last_workid - workid;
if (diff) {
MDB_ID2L dl = txn->mt_u.dirty_list;
int i;
for (i = dl[0].mid; i; i--) {
if (MDB_PGTXNID_FLAGBITS)
((MDB_page *)dl[i].mptr)->mp_txnid -= diff;
else
((MDB_page *)dl[i].mptr)->mp_txnid = workid;
}
txn->mt_workid = txn->mt_last_workid = workid;
}
} while ((txn = txn->mt_child) != NULL);
return workid;
}
int
mdb_txn_begin(MDB_env *env, MDB_txn *parent, unsigned int flags, MDB_txn **ret)
{
MDB_txn *txn;
MDB_ntxn *ntxn;
int rc, size, tsize;
flags &= MDB_TXN_BEGIN_FLAGS;
flags |= env->me_flags & MDB_WRITEMAP;
if (env->me_flags & MDB_RDONLY & ~flags) /* write txn in RDONLY env */
return EACCES;
if (parent) {
/* Nested transactions: Max 1 child, write txns only, no writemap */
flags |= parent->mt_flags;
if (flags & (MDB_RDONLY|MDB_WRITEMAP|MDB_TXN_BLOCKED)) {
return (parent->mt_flags & MDB_TXN_RDONLY) ? EINVAL : MDB_BAD_TXN;
}
/* Child txns save MDB_pgstate and use own copy of cursors */
size = env->me_maxdbs * (sizeof(MDB_db)+sizeof(MDB_cursor *)+1);
size += tsize = sizeof(MDB_ntxn);
} else if (flags & MDB_RDONLY) {
size = env->me_maxdbs * (sizeof(MDB_db)+1);
size += tsize = sizeof(MDB_txn);
} else {
/* Reuse preallocated write txn. However, do not touch it until
* mdb_txn_renew0() succeeds, since it currently may be active.
*/
txn = env->me_txn0;
goto renew;
}
if ((txn = calloc(1, size)) == NULL) {
DPRINTF(("calloc: %s", strerror(errno)));
return ENOMEM;
}
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags) && !parent) {
txn->mt_rpages = malloc(MDB_TRPAGE_SIZE * sizeof(MDB_ID3));
if (!txn->mt_rpages) {
free(txn);
return ENOMEM;
}
txn->mt_rpages[0].mid = 0;
txn->mt_rpcheck = MDB_TRPAGE_SIZE/2;
}
#endif
txn->mt_dbxs = env->me_dbxs; /* static */
txn->mt_dbs = (MDB_db *) ((char *)txn + tsize);
txn->mt_dbflags = (unsigned char *)txn + size - env->me_maxdbs;
txn->mt_flags = flags;
txn->mt_env = env;
if (parent) {
unsigned int i;
txnid_t workid = parent->mt_last_workid + MDB_PGTXNID_STEP;
if (!workid) /* wraparound after lots of previous children */
workid = mdb_workid_rewind(parent) + MDB_PGTXNID_STEP;
txn->mt_workid = txn->mt_last_workid = workid;
txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
txn->mt_dbiseqs = parent->mt_dbiseqs;
txn->mt_u.dirty_list = malloc(sizeof(MDB_ID2)*MDB_IDL_UM_SIZE);
if (!txn->mt_u.dirty_list ||
!(txn->mt_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)))
{
free(txn->mt_u.dirty_list);
free(txn);
return ENOMEM;
}
txn->mt_txnid = parent->mt_txnid;
txn->mt_dirty_room = parent->mt_dirty_room;
txn->mt_u.dirty_list[0].mid = 0;
txn->mt_spill_pgs = NULL;
#if OVERFLOW_NOTYET
txn->mt_dirty_ovs = NULL;
#endif
txn->mt_next_pgno = parent->mt_next_pgno;
parent->mt_flags |= MDB_TXN_HAS_CHILD;
parent->mt_child = txn;
txn->mt_parent = parent;
txn->mt_numdbs = parent->mt_numdbs;
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags))
txn->mt_rpages = parent->mt_rpages;
#endif
memcpy(txn->mt_dbs, parent->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
/* Copy parent's mt_dbflags, but clear DB_NEW */
for (i=0; i<txn->mt_numdbs; i++)
txn->mt_dbflags[i] = parent->mt_dbflags[i] & ~DB_NEW;
rc = 0;
ntxn = (MDB_ntxn *)txn;
ntxn->mnt_pgstate = env->me_pgstate; /* save parent me_pghead & co */
if (env->me_pghead) {
size = MDB_IDL_SIZEOF(env->me_pghead);
env->me_pghead = mdb_midl_alloc(env->me_pghead[0]);
if (env->me_pghead)
memcpy(env->me_pghead, ntxn->mnt_pgstate.mf_pghead, size);
else
rc = ENOMEM;
}
if (!rc)
rc = mdb_cursor_shadow(parent, txn);
if (rc)
mdb_txn_end(txn, MDB_END_FAIL_BEGINCHILD);
} else { /* MDB_RDONLY */
txn->mt_dbiseqs = env->me_dbiseqs;
renew:
rc = mdb_txn_renew0(txn);
}
if (rc) {
if (txn != env->me_txn0) {
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags))
free(txn->mt_rpages);
#endif
free(txn);
}
} else {
txn->mt_flags |= flags; /* could not change txn=me_txn0 earlier */
*ret = txn;
DPRINTF(("begin txn %"Yu"%c %p on mdbenv %p, root page %"Yu,
txn->mt_txnid, (flags & MDB_RDONLY) ? 'r' : 'w',
(void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root));
}
return rc;
}
MDB_env *
mdb_txn_env(MDB_txn *txn)
{
if(!txn) return NULL;
return txn->mt_env;
}
mdb_size_t
mdb_txn_id(MDB_txn *txn)
{
if(!txn) return 0;
return txn->mt_txnid;
}
/** Export or close DBI handles opened in this txn. */
static void
mdb_dbis_update(MDB_txn *txn, int keep)
{
int i;
MDB_dbi n = txn->mt_numdbs;
MDB_env *env = txn->mt_env;
unsigned char *tdbflags = txn->mt_dbflags;
for (i = n; --i >= CORE_DBS;) {
if (tdbflags[i] & DB_NEW) {
if (keep) {
env->me_dbflags[i] = txn->mt_dbs[i].md_flags | MDB_VALID;
} else {
char *ptr = env->me_dbxs[i].md_name.mv_data;
if (ptr) {
env->me_dbxs[i].md_name.mv_data = NULL;
env->me_dbxs[i].md_name.mv_size = 0;
env->me_dbflags[i] = 0;
env->me_dbiseqs[i]++;
free(ptr);
}
}
}
}
if (keep && env->me_numdbs < n)
env->me_numdbs = n;
}
/** End a transaction, except successful commit of a nested transaction.
* May be called twice for readonly txns: First reset it, then abort.
* @param[in] txn the transaction handle to end
* @param[in] mode why and how to end the transaction
*/
static void
mdb_txn_end(MDB_txn *txn, unsigned mode)
{
MDB_env *env = txn->mt_env;
#if MDB_DEBUG
static const char *const names[] = MDB_END_NAMES;
#endif
/* Export or close DBI handles opened in this txn */
mdb_dbis_update(txn, mode & MDB_END_UPDATE);
DPRINTF(("%s txn %"Yu"%c %p on mdbenv %p, root page %"Yu,
names[mode & MDB_END_OPMASK],
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root));
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
if (txn->mt_u.reader) {
txn->mt_u.reader->mr_txnid = (txnid_t)-1;
if (!(env->me_flags & MDB_NOTLS)) {
txn->mt_u.reader = NULL; /* txn does not own reader */
} else if (mode & MDB_END_SLOT) {
txn->mt_u.reader->mr_pid = 0;
txn->mt_u.reader = NULL;
} /* else txn owns the slot until it does MDB_END_SLOT */
}
txn->mt_numdbs = 0; /* prevent further DBI activity */
txn->mt_flags |= MDB_TXN_FINISHED;
} else if (!F_ISSET(txn->mt_flags, MDB_TXN_FINISHED)) {
pgno_t *pghead = env->me_pghead;
if (!(mode & MDB_END_UPDATE)) /* !(already closed cursors) */
mdb_cursors_close(txn, 0);
if (!(env->me_flags & MDB_WRITEMAP)) {
mdb_dlist_free(txn);
}
txn->mt_numdbs = 0;
txn->mt_flags = MDB_TXN_FINISHED;
if (!txn->mt_parent) {
mdb_midl_shrink(&txn->mt_free_pgs);
env->me_free_pgs = txn->mt_free_pgs;
/* me_pgstate: */
env->me_pghead = NULL;
env->me_pglast = 0;
env->me_txn = NULL;
mode = 0; /* txn == env->me_txn0, do not free() it */
/* The writer mutex was locked in mdb_txn_begin. */
if (env->me_txns)
UNLOCK_MUTEX(env->me_wmutex);
} else {
txn->mt_parent->mt_child = NULL;
txn->mt_parent->mt_flags &= ~MDB_TXN_HAS_CHILD;
env->me_pgstate = ((MDB_ntxn *)txn)->mnt_pgstate;
mdb_midl_free(txn->mt_free_pgs);
free(txn->mt_u.dirty_list);
}
mdb_midl_free(txn->mt_spill_pgs);
#if OVERFLOW_NOTYET
mdb_mid2l_free(txn->mt_dirty_ovs);
#endif
mdb_midl_free(pghead);
}
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags) && !txn->mt_parent) {
MDB_ID3L el = env->me_rpages, tl = txn->mt_rpages;
unsigned i, x, n = tl[0].mid;
pthread_mutex_lock(&env->me_rpmutex);
for (i = 1; i <= n; i++) {
if (tl[i].mid & (MDB_RPAGE_CHUNK-1)) {
/* tmp overflow pages that we didn't share in env */
munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);
if (tl[i].menc) {
mdb_rpage_dispose(env, &tl[i]);
tl[i].menc = NULL;
}
} else {
x = mdb_mid3l_search(el, tl[i].mid);
if (tl[i].mptr == el[x].mptr) {
el[x].mref--;
if (!el[x].mref)
el[x].muse = 0;
} else {
/* another tmp overflow page */
munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);
if (tl[i].menc) {
mdb_rpage_dispose(env, &tl[i]);
tl[i].menc = NULL;
}
}
}
}
pthread_mutex_unlock(&env->me_rpmutex);
tl[0].mid = 0;
if (mode & MDB_END_FREE)
free(tl);
}
#endif
if (mode & MDB_END_FREE)
free(txn);
}
void
mdb_txn_reset(MDB_txn *txn)
{
if (txn == NULL)
return;
/* This call is only valid for read-only txns */
if (!(txn->mt_flags & MDB_TXN_RDONLY))
return;
mdb_txn_end(txn, MDB_END_RESET);
}
void
mdb_txn_abort(MDB_txn *txn)
{
if (txn == NULL)
return;
if (txn->mt_child)
mdb_txn_abort(txn->mt_child);
mdb_txn_end(txn, MDB_END_ABORT|MDB_END_SLOT|MDB_END_FREE);
}
/** Save the freelist as of this transaction to the freeDB.
* This changes the freelist. Keep trying until it stabilizes.
*
* When (MDB_DEVEL) & 2, the changes do not affect #mdb_page_alloc(),
* it then uses the transaction's original snapshot of the freeDB.
*/
static int
mdb_freelist_save(MDB_txn *txn)
{
/* env->me_pghead[] can grow and shrink during this call.
* env->me_pglast and txn->mt_free_pgs[] can only grow.
* Page numbers cannot disappear from txn->mt_free_pgs[].
*/
MDB_cursor mc;
MDB_env *env = txn->mt_env;
int rc, maxfree_1pg = env->me_maxfree_1pg, more = 1, lost_loose = 0;
txnid_t pglast = 0, head_id = 0;
pgno_t freecnt = 0, *free_pgs, *mop;
ssize_t head_room = 0, total_room = 0, mop_len, clean_limit;
mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
if (env->me_pghead) {
/* Make sure first page of freeDB is touched and on freelist */
rc = mdb_page_search(&mc, NULL, MDB_PS_FIRST|MDB_PS_MODIFY);
if (rc && rc != MDB_NOTFOUND)
return rc;
}
if (!env->me_pghead && txn->mt_loose_pgs) {
/* Put loose page numbers in mt_free_pgs, since
* we may be unable to return them to me_pghead.
*/
MDB_page *mp = txn->mt_loose_pgs;
MDB_ID2 *dl = txn->mt_u.dirty_list;
unsigned x;
if ((rc = mdb_midl_need(&txn->mt_free_pgs, txn->mt_loose_count)) != 0)
return rc;
lost_loose = txn->mt_loose_count;
for (; mp; mp = NEXT_LOOSE_PAGE(mp)) {
mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
/* must also remove from dirty list */
if (txn->mt_flags & MDB_TXN_WRITEMAP) {
for (x=1; x<=dl[0].mid; x++)
if (dl[x].mid == mp->mp_pgno)
break;
mdb_tassert(txn, x <= dl[0].mid);
} else {
x = mdb_mid2l_search(dl, mp->mp_pgno);
mdb_tassert(txn, dl[x].mid == mp->mp_pgno);
mdb_dpage_free(env, mp);
}
dl[x].mptr = NULL;
}
{
/* squash freed slots out of the dirty list */
unsigned y;
for (y=1; dl[y].mptr && y <= dl[0].mid; y++);
if (y <= dl[0].mid) {
for(x=y, y++;;) {
while (!dl[y].mptr && y <= dl[0].mid) y++;
if (y > dl[0].mid) break;
dl[x++] = dl[y++];
}
dl[0].mid = x-1;
} else {
/* all slots freed */
dl[0].mid = 0;
}
}
txn->mt_loose_pgs = NULL;
txn->mt_loose_count = 0;
}
/* MDB_RESERVE cancels meminit in ovpage malloc (when no WRITEMAP) */
clean_limit = (env->me_flags & (MDB_NOMEMINIT|MDB_WRITEMAP))
? SSIZE_MAX : maxfree_1pg;
for (;;) {
/* Come back here after each Put() in case freelist changed */
MDB_val key, data;
pgno_t *pgs;
ssize_t j;
/* If using records from freeDB which we have not yet
* deleted, delete them and any we reserved for me_pghead.
*/
while (pglast < env->me_pglast) {
rc = mdb_cursor_first(&mc, &key, NULL);
if (rc)
return rc;
pglast = head_id = *(txnid_t *)key.mv_data;
total_room = head_room = 0;
mdb_tassert(txn, pglast <= env->me_pglast);
rc = mdb_cursor_del(&mc, 0);
if (rc)
return rc;
}
/* Save the IDL of pages freed by this txn, to a single record */
if (freecnt < txn->mt_free_pgs[0]) {
if (!freecnt) {
/* Make sure last page of freeDB is touched and on freelist */
rc = mdb_page_search(&mc, NULL, MDB_PS_LAST|MDB_PS_MODIFY);
if (rc && rc != MDB_NOTFOUND)
return rc;
}
free_pgs = txn->mt_free_pgs;
/* Write to last page of freeDB */
key.mv_size = sizeof(txn->mt_txnid);
key.mv_data = &txn->mt_txnid;
do {
freecnt = free_pgs[0];
data.mv_size = MDB_IDL_SIZEOF(free_pgs);
rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
if (rc)
return rc;
/* Retry if mt_free_pgs[] grew during the Put() */
free_pgs = txn->mt_free_pgs;
} while (freecnt < free_pgs[0]);
mdb_midl_sort(free_pgs);
memcpy(data.mv_data, free_pgs, data.mv_size);
#if (MDB_DEBUG) > 1
{
unsigned int i = free_pgs[0];
DPRINTF(("IDL write txn %"Yu" root %"Yu" num %u",
txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, i));
for (; i; i--)
DPRINTF(("IDL %"Yu, free_pgs[i]));
}
#endif
continue;
}
mop = env->me_pghead;
mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count;
/* Reserve records for me_pghead[]. Split it if multi-page,
* to avoid searching freeDB for a page range. Use keys in
* range [1,me_pglast]: Smaller than txnid of oldest reader.
*/
if (total_room >= mop_len) {
if (total_room == mop_len || --more < 0)
break;
} else if (head_room >= maxfree_1pg && head_id > 1) {
/* Keep current record (overflow page), add a new one */
head_id--;
head_room = 0;
}
/* (Re)write {key = head_id, IDL length = head_room} */
total_room -= head_room;
head_room = mop_len - total_room;
if (head_room > maxfree_1pg && head_id > 1) {
/* Overflow multi-page for part of me_pghead */
head_room /= head_id; /* amortize page sizes */
head_room += maxfree_1pg - head_room % (maxfree_1pg + 1);
} else if (head_room < 0) {
/* Rare case, not bothering to delete this record */
head_room = 0;
}
key.mv_size = sizeof(head_id);
key.mv_data = &head_id;
data.mv_size = (head_room + 1) * sizeof(pgno_t);
rc = mdb_cursor_put(&mc, &key, &data, MDB_RESERVE);
if (rc)
return rc;
/* IDL is initially empty, zero out at least the length */
pgs = (pgno_t *)data.mv_data;
j = head_room > clean_limit ? head_room : 0;
do {
pgs[j] = 0;
} while (--j >= 0);
total_room += head_room;
}
/* Return loose page numbers to me_pghead, though usually none are
* left at this point. The pages themselves remain in dirty_list.
*/
if (txn->mt_loose_pgs) {
MDB_page *mp = txn->mt_loose_pgs;
unsigned count = txn->mt_loose_count;
MDB_IDL loose;
/* Room for loose pages + temp IDL with same */
if ((rc = mdb_midl_need(&env->me_pghead, 2*count+1)) != 0)
return rc;
lost_loose += count;
mop = env->me_pghead;
loose = mop + MDB_IDL_ALLOCLEN(mop) - count;
for (count = 0; mp; mp = NEXT_LOOSE_PAGE(mp))
loose[ ++count ] = mp->mp_pgno;
loose[0] = count;
mdb_midl_sort(loose);
mdb_midl_xmerge(mop, loose);
txn->mt_loose_pgs = NULL;
txn->mt_loose_count = 0;
mop_len = mop[0];
}
/* Fill in the reserved me_pghead records. Everything is finally
* in place, so this will not allocate or free any DB pages.
*/
rc = MDB_SUCCESS;
if (mop_len) {
MDB_val key, data;
/* Protect DB env from any (buggy) freelist use when saving mop */
env->me_pghead = NULL;
txn->mt_dirty_room = 0;
mop += mop_len;
rc = mdb_cursor_first(&mc, &key, &data);
for (; !rc; rc = mdb_cursor_next(&mc, &key, &data, MDB_NEXT)) {
txnid_t id = *(txnid_t *)key.mv_data;
ssize_t len = (ssize_t)(data.mv_size / sizeof(MDB_ID)) - 1;
MDB_ID save;
mdb_tassert(txn, len >= 0 && id <= env->me_pglast);
key.mv_data = &id;
if (len > mop_len) {
len = mop_len;
data.mv_size = (len + 1) * sizeof(MDB_ID);
}
mop_len -= len;
data.mv_data = mop -= len;
save = mop[0];
mop[0] = len;
rc = mdb_cursor_put(&mc, &key, &data, MDB_CURRENT);
mop[0] = save;
if (rc || !mop_len)
break;
}
env->me_pghead = mop - mop_len;
}
/* Restore this so we can check vs. dirty_list after mdb_page_flush() */
if (! (txn->mt_flags & MDB_TXN_WRITEMAP))
txn->mt_loose_count += lost_loose;
return rc;
}
#if MDB_RPAGE_CACHE
static int mdb_rpage_decrypt(MDB_env *env, MDB_ID3 *id3, int rem, int numpgs);
static int mdb_page_encrypt(MDB_env *env, MDB_page *in, MDB_page *out, size_t size);
static int mdb_page_chk_checksum(MDB_env *env, MDB_page *mp, size_t size);
static void mdb_page_set_checksum(MDB_env *env, MDB_page *mp, size_t size);
#endif
/** Flush (some) dirty pages to the map, after clearing their dirty flag.
* @param[in] txn the transaction that's being committed
* @param[in] keep number of initial pages in dirty_list to keep dirty.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_flush(MDB_txn *txn, int keep)
{
MDB_env *env = txn->mt_env;
MDB_ID2L dl = txn->mt_u.dirty_list;
unsigned psize = env->me_psize, j;
int i, pagecount = dl[0].mid, rc, *dl_nump, nump = 1;
size_t size = 0;
MDB_OFF_T pos = 0;
pgno_t pgno = 0;
MDB_page *dp = NULL;
#ifdef _WIN32
OVERLAPPED *ov, *this_ov;
MDB_page *wdp;
int async_i = 0;
HANDLE fd = (env->me_flags & MDB_NOSYNC) ? env->me_fd : env->me_ovfd;
#else
struct iovec iov[MDB_COMMIT_PAGES];
HANDLE fd = env->me_fd;
#endif
ssize_t wsize = 0, wres;
MDB_OFF_T wpos = 0, next_pos = 1; /* impossible pos, so pos != next_pos */
int n = 0;
j = i = keep;
if (env->me_flags & MDB_WRITEMAP
#ifdef _WIN32
/* In windows, we still do writes to the file (with write-through enabled in sync mode),
* as this is faster than FlushViewOfFile/FlushFileBuffers */
&& (env->me_flags & MDB_NOSYNC)
#endif
) {
goto done;
}
/* setup nump list, flag that it's in use */
dl_nump = env->me_dirty_nump;
for (n=1; n<=pagecount; n++) {
dp = dl[n].mptr;
dl_nump[n] = IS_OVERFLOW(dp) ? dp->mp_pages : 1;
}
n = 0;
txn->mt_flags |= MDB_TXN_DIRTYNUM;
#ifdef _WIN32
if (pagecount - keep >= env->me_ovs) {
/* ran out of room in ov array, and re-malloc, copy handles and free previous */
int ovs = (pagecount - keep) * 1.5; /* provide extra padding to reduce number of re-allocations */
int new_size = ovs * sizeof(OVERLAPPED);
ov = malloc(new_size);
if (ov == NULL)
return ENOMEM;
int previous_size = env->me_ovs * sizeof(OVERLAPPED);
memcpy(ov, env->me_ov, previous_size); /* Copy previous OVERLAPPED data to retain event handles */
/* And clear rest of memory */
memset(&ov[env->me_ovs], 0, new_size - previous_size);
if (env->me_ovs > 0) {
free(env->me_ov); /* release previous allocation */
}
env->me_ov = ov;
env->me_ovs = ovs;
}
ov = env->me_ov;
#endif
/* Write the pages */
for (;;) {
if (++i <= pagecount) {
dp = dl[i].mptr;
/* Don't flush this page yet */
if (dp->mp_flags & (P_LOOSE|P_KEEP)) {
dp->mp_flags &= ~P_KEEP;
dl[i].mid = 0;
continue;
}
pgno = dl[i].mid;
/* Mark the page as clean */
dp->mp_txnid = txn->mt_txnid;
pos = pgno * psize;
size = psize;
nump = dl_nump[i];
size *= nump;
}
/* Write up to MDB_COMMIT_PAGES dirty pages at a time. */
if (pos!=next_pos || n==MDB_COMMIT_PAGES || wsize+size>MAX_WRITE
#ifdef _WIN32
/* Windows actually supports scatter/gather I/O, but only on
* unbuffered file handles. Since we're relying on the OS page
* cache for all our data, that's self-defeating. So we just
* write pages one at a time. We use the ov structure to set
* the write offset, to at least save the overhead of a Seek
* system call.
* If writemap is enabled, consecutive page positions infer
* contiguous (mapped) memory.
* Otherwise force write pages one at a time.
*/
|| !(env->me_flags & MDB_WRITEMAP)
#endif
) {
if (n) {
retry_write:
rc = 0;
/* Write previous page(s) */
#ifdef _WIN32
this_ov = &ov[async_i];
/* Clear status, and keep hEvent, we reuse that */
this_ov->Internal = 0;
this_ov->Offset = wpos & 0xffffffff;
this_ov->OffsetHigh = wpos >> 16 >> 16;
if (!F_ISSET(env->me_flags, MDB_NOSYNC) && !this_ov->hEvent) {
HANDLE event = CreateEvent(NULL, FALSE, FALSE, NULL);
if (!event) {
rc = ErrCode();
DPRINTF(("CreateEvent: %s", strerror(rc)));
return rc;
}
this_ov->hEvent = event;
}
if (!WriteFile(fd, wdp, wsize, NULL, this_ov)) {
rc = ErrCode();
if (rc != ERROR_IO_PENDING) {
DPRINTF(("WriteFile: %d", rc));
return rc;
}
rc = 0;
}
async_i++;
#else /* _WIN32 */
#ifdef MDB_USE_PWRITEV
wres = pwritev(fd, iov, n, wpos);
#else
if (n == 1) {
wres = pwrite(fd, iov[0].iov_base, wsize, wpos);
} else {
retry_seek:
if (lseek(fd, wpos, SEEK_SET) == -1) {
rc = ErrCode();
if (rc == EINTR)
goto retry_seek;
DPRINTF(("lseek: %s", strerror(rc)));
wres = wsize;
} else {
rc = 0;
wres = writev(fd, iov, n);
}
}
#endif
if (wres != wsize) {
if (wres < 0) {
rc = ErrCode();
if (rc == EINTR)
goto retry_write;
DPRINTF(("Write error: %s", strerror(rc)));
} else {
rc = EIO; /* TODO: Use which error code? */
DPUTS("short write, filesystem full?");
}
}
#endif /* _WIN32 */
if (rc)
return rc;
n = 0;
}
if (i > pagecount)
break;
wpos = pos;
wsize = 0;
}
#if MDB_RPAGE_CACHE
if (env->me_sumfunc) {
mdb_page_set_checksum(env, dp, size);
}
if (env->me_encfunc) {
MDB_page *encp = mdb_page_malloc(txn, nump, 0);
if (!encp)
return ENOMEM;
if (mdb_page_encrypt(env, dp, encp, size)) {
mdb_dpage_free_n(env, encp, nump);
return MDB_CRYPTO_FAIL;
}
mdb_dpage_free_n(env, dp, nump);
dp = encp;
dl[i].mptr = dp;
}
#endif
#ifdef _WIN32
wdp = dp;
#else
iov[n].iov_len = size;
iov[n].iov_base = (char *)dp;
#endif
DPRINTF(("committing page %"Yu, pgno));
next_pos = pos + size;
wsize += size;
n++;
}
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags) && pgno > txn->mt_last_pgno)
txn->mt_last_pgno = pgno;
#endif
/* MIPS has cache coherency issues, this is a no-op everywhere else
* Note: for any size >= on-chip cache size, entire on-chip cache is
* flushed.
*/
CACHEFLUSH(env->me_map, txn->mt_next_pgno * env->me_psize, DCACHE);
#ifdef _WIN32
if (!F_ISSET(env->me_flags, MDB_NOSYNC)) {
/* Now wait for all the asynchronous/overlapped sync/write-through writes to complete.
* We start with the last one so that all the others should already be complete and
* we reduce thread suspend/resuming (in practice, typically about 99.5% of writes are
* done after the last write is done) */
rc = 0;
while (--async_i >= 0) {
if (ov[async_i].hEvent) {
if (!GetOverlappedResult(fd, &ov[async_i], &wres, TRUE)) {
rc = ErrCode(); /* Continue on so that all the event signals are reset */
}
}
}
if (rc) { /* any error on GetOverlappedResult, exit now */
return rc;
}
}
#endif /* _WIN32 */
if (!(env->me_flags & MDB_WRITEMAP)) {
/* Don't free pages when using writemap (can only get here in NOSYNC mode in Windows)
*/
for (i = keep; ++i <= pagecount; ) {
dp = dl[i].mptr;
/* This is a page we skipped above */
if (!dl[i].mid) {
dl[++j] = dl[i];
dl[j].mid = dp->mp_pgno;
continue;
}
mdb_dpage_free_n(env, dp, dl_nump[i]);
}
}
txn->mt_flags ^= MDB_TXN_DIRTYNUM;
done:
i--;
txn->mt_dirty_room += i - j;
dl[0].mid = j;
return MDB_SUCCESS;
}
static int ESECT mdb_env_share_locks(MDB_env *env, int *excl);
int
mdb_txn_commit(MDB_txn *txn)
{
int rc;
unsigned int i, end_mode;
MDB_env *env;
if (txn == NULL)
return EINVAL;
/* mdb_txn_end() mode for a commit which writes nothing */
end_mode = MDB_END_EMPTY_COMMIT|MDB_END_UPDATE|MDB_END_SLOT|MDB_END_FREE;
if (txn->mt_child) {
rc = mdb_txn_commit(txn->mt_child);
if (rc)
goto fail;
}
env = txn->mt_env;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
goto done;
}
if (txn->mt_flags & (MDB_TXN_FINISHED|MDB_TXN_ERROR)) {
DPUTS("txn has failed/finished, can't commit");
if (txn->mt_parent)
txn->mt_parent->mt_flags |= MDB_TXN_ERROR;
rc = MDB_BAD_TXN;
goto fail;
}
if (txn->mt_parent) {
MDB_txn *parent = txn->mt_parent;
MDB_page **lp;
MDB_ID2L dst, src;
MDB_IDL pspill;
unsigned x, y, len, ps_len;
/* Append our free list to parent's */
rc = mdb_midl_append_list(&parent->mt_free_pgs, txn->mt_free_pgs);
if (rc)
goto fail;
mdb_midl_free(txn->mt_free_pgs);
/* Failures after this must either undo the changes
* to the parent or set MDB_TXN_ERROR in the parent.
*/
parent->mt_next_pgno = txn->mt_next_pgno;
parent->mt_flags = txn->mt_flags;
/* Merge our cursors into parent's and close them */
mdb_cursors_close(txn, 1);
/* Update parent's DB table. */
memcpy(parent->mt_dbs, txn->mt_dbs, txn->mt_numdbs * sizeof(MDB_db));
parent->mt_numdbs = txn->mt_numdbs;
parent->mt_dbflags[FREE_DBI] = txn->mt_dbflags[FREE_DBI];
parent->mt_dbflags[MAIN_DBI] = txn->mt_dbflags[MAIN_DBI];
for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
/* preserve parent's DB_NEW status */
x = parent->mt_dbflags[i] & DB_NEW;
parent->mt_dbflags[i] = txn->mt_dbflags[i] | x;
}
dst = parent->mt_u.dirty_list;
src = txn->mt_u.dirty_list;
/* Remove anything in our dirty list from parent's spill list */
if ((pspill = parent->mt_spill_pgs) && (ps_len = pspill[0])) {
x = y = ps_len;
pspill[0] = (pgno_t)-1;
/* Mark our dirty pages as deleted in parent spill list */
for (i=0, len=src[0].mid; ++i <= len; ) {
MDB_ID pn = src[i].mid << 1;
while (pn > pspill[x])
x--;
if (pn == pspill[x]) {
pspill[x] = 1;
y = --x;
}
}
/* Squash deleted pagenums if we deleted any */
for (x=y; ++x <= ps_len; )
if (!(pspill[x] & 1))
pspill[++y] = pspill[x];
pspill[0] = y;
}
/* Remove anything in our spill list from parent's dirty list */
if (txn->mt_spill_pgs && txn->mt_spill_pgs[0]) {
for (i=1; i<=txn->mt_spill_pgs[0]; i++) {
MDB_ID pn = txn->mt_spill_pgs[i];
if (pn & 1)
continue; /* deleted spillpg */
pn >>= 1;
y = mdb_mid2l_search(dst, pn);
if (y <= dst[0].mid && dst[y].mid == pn) {
free(dst[y].mptr);
while (y < dst[0].mid) {
dst[y] = dst[y+1];
y++;
}
dst[0].mid--;
}
}
}
/* Find len = length of merging our dirty list with parent's */
x = dst[0].mid;
dst[0].mid = 0; /* simplify loops */
if (parent->mt_parent) {
len = x + src[0].mid;
y = mdb_mid2l_search(src, dst[x].mid + 1) - 1;
for (i = x; y && i; y--) {
pgno_t yp = src[y].mid;
while (yp < dst[i].mid)
i--;
if (yp == dst[i].mid) {
i--;
len--;
}
}
} else { /* Simplify the above for single-ancestor case */
len = MDB_IDL_UM_MAX - txn->mt_dirty_room;
}
/* Merge our dirty list with parent's */
y = src[0].mid;
for (i = len; y; dst[i--] = src[y--]) {
pgno_t yp = src[y].mid;
while (yp < dst[x].mid)
dst[i--] = dst[x--];
if (yp == dst[x].mid)
free(dst[x--].mptr);
}
mdb_tassert(txn, i == x);
dst[0].mid = len;
free(txn->mt_u.dirty_list);
parent->mt_dirty_room = txn->mt_dirty_room;
if (txn->mt_spill_pgs) {
if (parent->mt_spill_pgs) {
/* TODO: Prevent failure here, so parent does not fail */
rc = mdb_midl_append_list(&parent->mt_spill_pgs, txn->mt_spill_pgs);
if (rc)
parent->mt_flags |= MDB_TXN_ERROR;
mdb_midl_free(txn->mt_spill_pgs);
mdb_midl_sort(parent->mt_spill_pgs);
} else {
parent->mt_spill_pgs = txn->mt_spill_pgs;
}
}
/* Append our loose page list to parent's */
for (lp = &parent->mt_loose_pgs; *lp; lp = &NEXT_LOOSE_PAGE(*lp))
;
*lp = txn->mt_loose_pgs;
parent->mt_loose_count += txn->mt_loose_count;
parent->mt_last_workid = txn->mt_last_workid;
parent->mt_child = NULL;
mdb_midl_free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pghead);
free(txn);
return rc;
}
if (txn != env->me_txn) {
DPUTS("attempt to commit unknown transaction");
rc = EINVAL;
goto fail;
}
mdb_cursors_close(txn, 0);
if (!txn->mt_u.dirty_list[0].mid &&
!(txn->mt_flags & (MDB_TXN_DIRTY|MDB_TXN_SPILLS)))
goto done;
DPRINTF(("committing txn %"Yu" %p on mdbenv %p, root page %"Yu,
txn->mt_txnid, (void*)txn, (void*)env, txn->mt_dbs[MAIN_DBI].md_root));
/* Update DB root pointers */
if (txn->mt_numdbs > CORE_DBS) {
MDB_cursor mc;
MDB_dbi i;
MDB_val data;
data.mv_size = sizeof(MDB_db);
mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
for (i = CORE_DBS; i < txn->mt_numdbs; i++) {
if (txn->mt_dbflags[i] & DB_DIRTY) {
if (TXN_DBI_CHANGED(txn, i)) {
rc = MDB_BAD_DBI;
goto fail;
}
data.mv_data = &txn->mt_dbs[i];
rc = mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data,
F_SUBDATA);
if (rc)
goto fail;
}
}
}
rc = mdb_freelist_save(txn);
if (rc)
goto fail;
mdb_midl_free(env->me_pghead);
env->me_pghead = NULL;
mdb_midl_shrink(&txn->mt_free_pgs);
#if (MDB_DEBUG) > 2
mdb_audit(txn);
#endif
if ((rc = mdb_page_flush(txn, 0)))
goto fail;
if ((unsigned)txn->mt_loose_count != txn->mt_u.dirty_list[0].mid) {
rc = MDB_PROBLEM; /* mt_loose_pgs does not match dirty_list */
goto fail;
}
if (!F_ISSET(txn->mt_flags, MDB_TXN_NOSYNC) &&
(rc = mdb_env_sync0(env, 0, txn->mt_next_pgno)))
goto fail;
if ((rc = mdb_env_write_meta(txn)))
goto fail;
end_mode = MDB_END_COMMITTED|MDB_END_UPDATE;
if (env->me_flags & MDB_PREVSNAPSHOT) {
if (!(env->me_flags & MDB_NOLOCK)) {
int excl;
rc = mdb_env_share_locks(env, &excl);
if (rc)
goto fail;
}
env->me_flags ^= MDB_PREVSNAPSHOT;
}
done:
mdb_txn_end(txn, end_mode);
return MDB_SUCCESS;
fail:
mdb_txn_abort(txn);
return rc;
}
static int ESECT mdb_env_map(MDB_env *env, void *addr);
/** Read the environment parameters of a DB environment before
* mapping it into memory.
* @param[in] env the environment handle
* @param[in] prev whether to read the backup meta page
* @param[out] meta address of where to store the meta information
* @return 0 on success, non-zero on failure.
*/
static int ESECT
mdb_env_read_header(MDB_env *env, int prev, MDB_meta *meta)
{
MDB_metabuf pbuf;
MDB_page *p;
MDB_meta *m;
int i, rc, off;
enum { Size = sizeof(pbuf) };
if (env->me_flags & MDB_RAWPART) {
#define VM_ALIGN 0x200000
env->me_mapsize += VM_ALIGN-1;
env->me_mapsize &= ~(VM_ALIGN-1);
env->me_psize = env->me_os_psize;
rc = mdb_env_map(env, NULL);
if (rc)
return rc;
p = (MDB_page *)env->me_map;
for (i=0; i<NUM_METAS; i++) {
if (!F_ISSET(p->mp_flags, P_META))
return ENOENT;
if (env->me_metas[i]->mm_magic != MDB_MAGIC)
return MDB_INVALID;
if (env->me_metas[i]->mm_version != MDB_DATA_VERSION)
return MDB_VERSION_MISMATCH;
if (i == 0 || env->me_metas[i]->mm_txnid > meta->mm_txnid)
*meta = *env->me_metas[i];
p = (MDB_page *)((char *)p + env->me_psize);
}
return 0;
}
/* We don't know the page size yet, so use a minimum value.
* Read both meta pages so we can use the latest one.
*/
for (i=off=0; i<NUM_METAS; i++, off += meta->mm_psize) {
#ifdef _WIN32
DWORD len;
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
ov.Offset = off;
rc = ReadFile(env->me_fd, &pbuf, Size, &len, &ov) ? (int)len : -1;
if (rc == -1 && ErrCode() == ERROR_HANDLE_EOF)
rc = 0;
#else
rc = pread(env->me_fd, &pbuf, Size, off);
#endif
if (rc != Size) {
if (rc == 0 && off == 0)
return ENOENT;
rc = rc < 0 ? (int) ErrCode() : MDB_INVALID;
DPRINTF(("read: %s", mdb_strerror(rc)));
return rc;
}
p = (MDB_page *)&pbuf;
if (!F_ISSET(p->mp_flags, P_META)) {
if (env->me_flags & MDB_RAWPART)
return ENOENT;
DPRINTF(("page %"Yu" not a meta page", p->mp_pgno));
return MDB_INVALID;
}
m = METADATA(p);
if (m->mm_magic != MDB_MAGIC) {
DPUTS("meta has invalid magic");
return MDB_INVALID;
}
if (m->mm_version != MDB_DATA_VERSION) {
DPRINTF(("database is version %u, expected version %u",
m->mm_version, MDB_DATA_VERSION));
return MDB_VERSION_MISMATCH;
}
if (off == 0 || (prev ? m->mm_txnid < meta->mm_txnid : m->mm_txnid > meta->mm_txnid))
*meta = *m;
}
return 0;
}
/** Fill in most of the zeroed #MDB_meta for an empty database environment */
static void ESECT
mdb_env_init_meta0(MDB_env *env, MDB_meta *meta)
{
meta->mm_magic = MDB_MAGIC;
meta->mm_version = MDB_DATA_VERSION;
meta->mm_mapsize = env->me_mapsize;
meta->mm_psize = env->me_psize;
meta->mm_last_pg = NUM_METAS-1;
meta->mm_flags = env->me_flags & 0xffff;
meta->mm_flags |= MDB_INTEGERKEY; /* this is mm_dbs[FREE_DBI].md_flags */
meta->mm_dbs[FREE_DBI].md_root = P_INVALID;
meta->mm_dbs[MAIN_DBI].md_root = P_INVALID;
}
/** Write the environment parameters of a freshly created DB environment.
* @param[in] env the environment handle
* @param[in] meta the #MDB_meta to write
* @return 0 on success, non-zero on failure.
*/
static int ESECT
mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
{
MDB_page *p, *q;
int rc;
unsigned int psize;
#ifdef _WIN32
DWORD len;
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
#define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
ov.Offset = pos; \
rc = WriteFile(fd, ptr, size, &len, &ov); } while(0)
#else
int len;
#define DO_PWRITE(rc, fd, ptr, size, len, pos) do { \
len = pwrite(fd, ptr, size, pos); \
if (len == -1 && ErrCode() == EINTR) continue; \
rc = (len >= 0); break; } while(1)
#endif
DPUTS("writing new meta page");
psize = env->me_psize;
if ((env->me_flags & (MDB_RAWPART|MDB_WRITEMAP)) == (MDB_RAWPART|MDB_WRITEMAP)) {
p = (MDB_page *)env->me_map;
p->mp_pgno = 0;
p->mp_flags = P_META;
*(MDB_meta *)METADATA(p) = *meta;
q = (MDB_page *)((char *)p + psize);
q->mp_pgno = 1;
q->mp_flags = P_META;
*(MDB_meta *)METADATA(q) = *meta;
return 0;
}
p = calloc(NUM_METAS, psize);
if (!p)
return ENOMEM;
p->mp_pgno = 0;
p->mp_flags = P_META;
*(MDB_meta *)METADATA(p) = *meta;
q = (MDB_page *)((char *)p + psize);
q->mp_pgno = 1;
q->mp_flags = P_META;
*(MDB_meta *)METADATA(q) = *meta;
#if MDB_RPAGE_CACHE
if (env->me_sumsize) {
/* save the checksum size in tail of page 0 */
char *ptr = (char *)q;
unsigned short *u = (unsigned short *)(ptr-2);
*u = env->me_sumsize;
}
#endif
DO_PWRITE(rc, env->me_fd, p, psize * NUM_METAS, len, 0);
if (!rc)
rc = ErrCode();
else if ((unsigned) len == psize * NUM_METAS)
rc = MDB_SUCCESS;
else
rc = ENOSPC;
free(p);
return rc;
}
/** Update the environment info to commit a transaction.
* @param[in] txn the transaction that's being committed
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_write_meta(MDB_txn *txn)
{
MDB_env *env;
MDB_meta meta, metab, *mp;
unsigned flags;
mdb_size_t mapsize;
MDB_OFF_T off;
int rc, len, toggle;
char *ptr;
HANDLE mfd;
#ifdef _WIN32
OVERLAPPED ov;
#else
int r2;
#endif
toggle = txn->mt_txnid & 1;
DPRINTF(("writing meta page %d for root page %"Yu,
toggle, txn->mt_dbs[MAIN_DBI].md_root));
env = txn->mt_env;
flags = txn->mt_flags | env->me_flags;
mp = env->me_metas[toggle];
mapsize = env->me_metas[toggle ^ 1]->mm_mapsize;
/* Persist any increases of mapsize config */
if (mapsize < env->me_mapsize)
mapsize = env->me_mapsize;
#ifndef _WIN32 /* We don't want to ever use MSYNC/FlushViewOfFile in Windows */
if (flags & MDB_WRITEMAP) {
mp->mm_mapsize = mapsize;
mp->mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];
mp->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
mp->mm_last_pg = txn->mt_next_pgno - 1;
#if (__GNUC__ * 100 + __GNUC_MINOR__ >= 404) && /* TODO: portability */ \
!(defined(__i386__) || defined(__x86_64__))
/* LY: issue a memory barrier, if not x86. ITS#7969 */
__sync_synchronize();
#endif
mp->mm_txnid = txn->mt_txnid;
if (!(flags & (MDB_NOMETASYNC|MDB_NOSYNC))) {
unsigned meta_size = env->me_psize;
rc = (env->me_flags & MDB_MAPASYNC) ? MS_ASYNC : MS_SYNC;
ptr = (char *)mp - PAGEHDRSZ;
/* POSIX msync() requires ptr = start of OS page */
r2 = (ptr - env->me_map) & (env->me_os_psize - 1);
ptr -= r2;
meta_size += r2;
if (MDB_MSYNC(ptr, meta_size, rc)) {
rc = ErrCode();
goto fail;
}
}
goto done;
}
#endif
metab.mm_txnid = mp->mm_txnid;
metab.mm_last_pg = mp->mm_last_pg;
meta.mm_mapsize = mapsize;
meta.mm_dbs[FREE_DBI] = txn->mt_dbs[FREE_DBI];
meta.mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
meta.mm_last_pg = txn->mt_next_pgno - 1;
meta.mm_txnid = txn->mt_txnid;
off = offsetof(MDB_meta, mm_mapsize);
ptr = (char *)&meta + off;
len = sizeof(MDB_meta) - off;
off += (char *)mp - env->me_map;
/* Write to the SYNC fd unless MDB_NOSYNC/MDB_NOMETASYNC.
* (me_mfd goes to the same file as me_fd, but writing to it
* also syncs to disk. Avoids a separate fdatasync() call.)
*/
mfd = (flags & (MDB_NOSYNC|MDB_NOMETASYNC)) ? env->me_fd : env->me_mfd;
#ifdef _WIN32
{
memset(&ov, 0, sizeof(ov));
ov.Offset = off;
if (!WriteFile(mfd, ptr, len, (DWORD *)&rc, &ov))
rc = -1;
}
#else
retry_write:
rc = pwrite(mfd, ptr, len, off);
#endif
if (rc != len) {
rc = rc < 0 ? ErrCode() : EIO;
#ifndef _WIN32
if (rc == EINTR)
goto retry_write;
#endif
DPUTS("write failed, disk error?");
/* On a failure, the pagecache still contains the new data.
* Write some old data back, to prevent it from being used.
* Use the non-SYNC fd; we know it will fail anyway.
*/
meta.mm_last_pg = metab.mm_last_pg;
meta.mm_txnid = metab.mm_txnid;
#ifdef _WIN32
memset(&ov, 0, sizeof(ov));
ov.Offset = off;
WriteFile(env->me_fd, ptr, len, NULL, &ov);
#else
r2 = pwrite(env->me_fd, ptr, len, off);
(void)r2; /* Silence warnings. We don't care about pwrite's return value */
#endif
fail:
env->me_flags |= MDB_FATAL_ERROR;
return rc;
}
/* MIPS has cache coherency issues, this is a no-op everywhere else */
CACHEFLUSH(env->me_map + off, len, DCACHE);
done:
/* Memory ordering issues are irrelevant; since the entire writer
* is wrapped by wmutex, all of these changes will become visible
* after the wmutex is unlocked. Since the DB is multi-version,
* readers will get consistent data regardless of how fresh or
* how stale their view of these values is.
*/
if (env->me_txns)
env->me_txns->mti_txnid = txn->mt_txnid;
return MDB_SUCCESS;
}
/** Check both meta pages to see which one is newer.
* @param[in] env the environment handle
* @return newest #MDB_meta.
*/
static MDB_meta *
mdb_env_pick_meta(const MDB_env *env)
{
MDB_meta *const *metas = env->me_metas;
return metas[ (metas[0]->mm_txnid < metas[1]->mm_txnid) ^
((env->me_flags & MDB_PREVSNAPSHOT) != 0) ];
}
int ESECT
mdb_env_create(MDB_env **env)
{
MDB_env *e;
e = calloc(1, sizeof(MDB_env));
if (!e)
return ENOMEM;
e->me_maxreaders = DEFAULT_READERS;
e->me_maxdbs = e->me_numdbs = CORE_DBS;
e->me_fd = INVALID_HANDLE_VALUE;
e->me_lfd = INVALID_HANDLE_VALUE;
e->me_mfd = INVALID_HANDLE_VALUE;
#ifdef MDB_USE_POSIX_SEM
e->me_rmutex = SEM_FAILED;
e->me_wmutex = SEM_FAILED;
#elif defined MDB_USE_SYSV_SEM
e->me_rmutex->semid = -1;
e->me_wmutex->semid = -1;
#endif
e->me_pid = getpid();
GET_PAGESIZE(e->me_os_psize);
VGMEMP_CREATE(e,0,0);
*env = e;
return MDB_SUCCESS;
}
#ifdef _WIN32
/** @brief Map a result from an NTAPI call to WIN32. */
static DWORD
mdb_nt2win32(NTSTATUS st)
{
OVERLAPPED o = {0};
DWORD br;
o.Internal = st;
GetOverlappedResult(NULL, &o, &br, FALSE);
return GetLastError();
}
#endif
static int ESECT
mdb_env_map(MDB_env *env, void *addr)
{
MDB_page *p;
unsigned int flags = env->me_flags;
#ifdef _WIN32
int rc;
int access = SECTION_MAP_READ;
HANDLE mh;
void *map;
SIZE_T msize;
ULONG pageprot = PAGE_READONLY, secprot, alloctype;
if (flags & MDB_WRITEMAP) {
access |= SECTION_MAP_WRITE;
pageprot = PAGE_READWRITE;
}
if (flags & MDB_RDONLY) {
secprot = PAGE_READONLY;
msize = 0;
alloctype = 0;
} else {
secprot = PAGE_READWRITE;
msize = env->me_mapsize;
alloctype = MEM_RESERVE;
}
/** Some users are afraid of seeing their disk space getting used
* all at once, so the default is now to do incremental file growth.
* But that has a large performance impact, so give the option of
* allocating the file up front.
*/
#ifdef MDB_FIXEDSIZE
LARGE_INTEGER fsize;
fsize.LowPart = msize & 0xffffffff;
fsize.HighPart = msize >> 16 >> 16;
rc = NtCreateSection(&mh, access, NULL, &fsize, secprot, SEC_RESERVE, env->me_fd);
#else
rc = NtCreateSection(&mh, access, NULL, NULL, secprot, SEC_RESERVE, env->me_fd);
#endif
if (rc)
return mdb_nt2win32(rc);
map = addr;
if (MDB_REMAPPING(env->me_flags))
msize = NUM_METAS * env->me_psize;
rc = NtMapViewOfSection(mh, GetCurrentProcess(), &map, 0, 0, NULL, &msize, ViewUnmap, alloctype, pageprot);
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags))
env->me_fmh = mh;
else
#endif
NtClose(mh);
if (rc)
return mdb_nt2win32(rc);
env->me_map = map;
#else /* !_WIN32 */
int mmap_flags = MAP_SHARED;
int prot = PROT_READ;
if (flags & MDB_WRITEMAP)
prot |= PROT_WRITE;
#ifdef MAP_NOSYNC /* Used on FreeBSD */
if (flags & MDB_NOSYNC)
mmap_flags |= MAP_NOSYNC;
#endif
if (MDB_REMAPPING(env->me_flags)) {
(void) flags;
env->me_map = mmap(addr, NUM_METAS * env->me_psize, prot, mmap_flags,
env->me_fd, 0);
if (env->me_map == MAP_FAILED) {
env->me_map = NULL;
return ErrCode();
}
} else
{
if (flags & MDB_WRITEMAP) {
if (!(flags & MDB_RAWPART) && ftruncate(env->me_fd, env->me_mapsize) < 0)
return ErrCode();
}
env->me_map = mmap(addr, env->me_mapsize, prot, mmap_flags,
env->me_fd, 0);
if (env->me_map == MAP_FAILED) {
env->me_map = NULL;
return ErrCode();
}
if (flags & MDB_NORDAHEAD) {
/* Turn off readahead. It's harmful when the DB is larger than RAM. */
#ifdef MADV_RANDOM
madvise(env->me_map, env->me_mapsize, MADV_RANDOM);
#else
#ifdef POSIX_MADV_RANDOM
posix_madvise(env->me_map, env->me_mapsize, POSIX_MADV_RANDOM);
#endif /* POSIX_MADV_RANDOM */
#endif /* MADV_RANDOM */
}
}
#endif /* _WIN32 */
/* Can happen because the address argument to mmap() is just a
* hint. mmap() can pick another, e.g. if the range is in use.
* The MAP_FIXED flag would prevent that, but then mmap could
* instead unmap existing pages to make room for the new map.
*/
if (addr && env->me_map != addr)
return EBUSY; /* TODO: Make a new MDB_* error code? */
p = (MDB_page *)env->me_map;
env->me_metas[0] = METADATA(p);
env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + env->me_psize);
return MDB_SUCCESS;
}
int ESECT
mdb_env_set_mapsize(MDB_env *env, mdb_size_t size)
{
/* If env is already open, caller is responsible for making
* sure there are no active txns.
*/
if (env->me_map) {
MDB_meta *meta;
void *old;
int rc;
if (env->me_txn)
return EINVAL;
meta = mdb_env_pick_meta(env);
if (!size)
size = meta->mm_mapsize;
{
/* Silently round up to minimum if the size is too small */
mdb_size_t minsize = (meta->mm_last_pg + 1) * env->me_psize;
if (size < minsize)
size = minsize;
}
if (!(MDB_REMAPPING(env->me_flags)))
{
/* For MDB_REMAP_CHUNKS this bit is a noop since we dynamically remap
* chunks of the DB anyway.
*/
munmap(env->me_map, env->me_mapsize);
env->me_mapsize = size;
old = (env->me_flags & MDB_FIXEDMAP) ? env->me_map : NULL;
rc = mdb_env_map(env, old);
if (rc)
return rc;
}
}
env->me_mapsize = size;
if (env->me_psize)
env->me_maxpg = env->me_mapsize / env->me_psize;
return MDB_SUCCESS;
}
int ESECT
mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
{
if (env->me_map)
return EINVAL;
env->me_maxdbs = dbs + CORE_DBS;
return MDB_SUCCESS;
}
int ESECT
mdb_env_set_maxreaders(MDB_env *env, unsigned int readers)
{
if (env->me_map || readers < 1)
return EINVAL;
env->me_maxreaders = readers;
return MDB_SUCCESS;
}
int ESECT
mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
{
if (!env || !readers)
return EINVAL;
*readers = env->me_maxreaders;
return MDB_SUCCESS;
}
static int ESECT
mdb_fsize(HANDLE fd, mdb_size_t *size)
{
#ifdef _WIN32
LARGE_INTEGER fsize;
if (!GetFileSizeEx(fd, &fsize))
return ErrCode();
*size = fsize.QuadPart;
#else
struct stat st;
if (fstat(fd, &st))
return ErrCode();
*size = st.st_size;
#endif
return MDB_SUCCESS;
}
#ifdef _WIN32
typedef wchar_t mdb_nchar_t;
# define MDB_NAME(str) L##str
# define mdb_name_cpy wcscpy
#else
/** Character type for file names: char on Unix, wchar_t on Windows */
typedef char mdb_nchar_t;
# define MDB_NAME(str) str /**< #mdb_nchar_t[] string literal */
# define mdb_name_cpy strcpy /**< Copy name (#mdb_nchar_t string) */
#endif
/** Filename - string of #mdb_nchar_t[] */
typedef struct MDB_name {
int mn_len; /**< Length */
int mn_alloced; /**< True if #mn_val was malloced */
mdb_nchar_t *mn_val; /**< Contents */
} MDB_name;
/** Filename suffixes [datafile,lockfile][without,with MDB_NOSUBDIR] */
static const mdb_nchar_t *const mdb_suffixes[2][2] = {
{ MDB_NAME("/data.mdb"), MDB_NAME("") },
{ MDB_NAME("/lock.mdb"), MDB_NAME("-lock") }
};
#define MDB_SUFFLEN 9 /**< Max string length in #mdb_suffixes[] */
/** Set up filename + scratch area for filename suffix, for opening files.
* It should be freed with #mdb_fname_destroy().
* On Windows, paths are converted from char *UTF-8 to wchar_t *UTF-16.
*
* @param[in] path Pathname for #mdb_env_open().
* @param[in] envflags Whether a subdir and/or lockfile will be used.
* @param[out] fname Resulting filename, with room for a suffix if necessary.
*/
static int ESECT
mdb_fname_init(const char *path, unsigned envflags, MDB_name *fname)
{
int no_suffix = F_ISSET(envflags, MDB_NOSUBDIR|MDB_NOLOCK);
fname->mn_alloced = 0;
#ifdef _WIN32
return utf8_to_utf16(path, fname, no_suffix ? 0 : MDB_SUFFLEN);
#else
fname->mn_len = strlen(path);
if (no_suffix)
fname->mn_val = (char *) path;
else if ((fname->mn_val = malloc(fname->mn_len + MDB_SUFFLEN+1)) != NULL) {
fname->mn_alloced = 1;
strcpy(fname->mn_val, path);
}
else
return ENOMEM;
return MDB_SUCCESS;
#endif
}
/** Destroy \b fname from #mdb_fname_init() */
#define mdb_fname_destroy(fname) \
do { if ((fname).mn_alloced) free((fname).mn_val); } while (0)
#ifdef O_CLOEXEC /* POSIX.1-2008: Set FD_CLOEXEC atomically at open() */
# define MDB_CLOEXEC O_CLOEXEC
#else
# define MDB_CLOEXEC 0
#endif
/** File type, access mode etc. for #mdb_fopen() */
enum mdb_fopen_type {
#ifdef _WIN32
MDB_O_RDONLY, MDB_O_RDWR, MDB_O_OVERLAPPED, MDB_O_META, MDB_O_COPY, MDB_O_LOCKS
#else
/* A comment in mdb_fopen() explains some O_* flag choices. */
MDB_O_RDONLY= O_RDONLY, /**< for RDONLY me_fd */
MDB_O_RDWR = O_RDWR |O_CREAT, /**< for me_fd */
MDB_O_META = O_WRONLY|MDB_DSYNC |MDB_CLOEXEC, /**< for me_mfd */
MDB_O_COPY = O_WRONLY|O_CREAT|O_EXCL|MDB_CLOEXEC, /**< for #mdb_env_copy() */
/** Bitmask for open() flags in enum #mdb_fopen_type. The other bits
* distinguish otherwise-equal MDB_O_* constants from each other.
*/
MDB_O_MASK = MDB_O_RDWR|MDB_CLOEXEC | MDB_O_RDONLY|MDB_O_META|MDB_O_COPY,
MDB_O_LOCKS = MDB_O_RDWR|MDB_CLOEXEC | ((MDB_O_MASK+1) & ~MDB_O_MASK) /**< for me_lfd */
#endif
};
/** Open an LMDB file.
* @param[in] env The LMDB environment.
* @param[in,out] fname Path from from #mdb_fname_init(). A suffix is
* appended if necessary to create the filename, without changing mn_len.
* @param[in] which Determines file type, access mode, etc.
* @param[in] mode The Unix permissions for the file, if we create it.
* @param[out] res Resulting file handle.
* @return 0 on success, non-zero on failure.
*/
static int ESECT
mdb_fopen(const MDB_env *env, MDB_name *fname,
enum mdb_fopen_type which, mdb_mode_t mode,
HANDLE *res)
{
int rc = MDB_SUCCESS;
HANDLE fd;
#ifdef _WIN32
DWORD acc, share, disp, attrs;
#else
int flags;
#endif
if (fname->mn_alloced) /* modifiable copy */
mdb_name_cpy(fname->mn_val + fname->mn_len,
mdb_suffixes[which==MDB_O_LOCKS][F_ISSET(env->me_flags, MDB_NOSUBDIR)]);
/* The directory must already exist. Usually the file need not.
* MDB_O_META requires the file because we already created it using
* MDB_O_RDWR. MDB_O_COPY must not overwrite an existing file.
*
* With MDB_O_COPY we do not want the OS to cache the writes, since
* the source data is already in the OS cache.
*
* The lockfile needs FD_CLOEXEC (close file descriptor on exec*())
* to avoid the flock() issues noted under Caveats in lmdb.h.
* Also set it for other filehandles which the user cannot get at
* and close himself, which he may need after fork(). I.e. all but
* me_fd, which programs do use via mdb_env_get_fd().
*/
#ifdef _WIN32
acc = GENERIC_READ|GENERIC_WRITE;
share = FILE_SHARE_READ|FILE_SHARE_WRITE;
disp = OPEN_ALWAYS;
attrs = FILE_ATTRIBUTE_NORMAL;
switch (which) {
case MDB_O_OVERLAPPED: /* for unbuffered asynchronous writes (write-through mode)*/
acc = GENERIC_WRITE;
disp = OPEN_EXISTING;
attrs = FILE_FLAG_OVERLAPPED|FILE_FLAG_WRITE_THROUGH;
break;
case MDB_O_RDONLY: /* read-only datafile */
acc = GENERIC_READ;
disp = OPEN_EXISTING;
break;
case MDB_O_META: /* for writing metapages */
acc = GENERIC_WRITE;
disp = OPEN_EXISTING;
attrs = FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH;
break;
case MDB_O_COPY: /* mdb_env_copy() & co */
acc = GENERIC_WRITE;
share = 0;
disp = CREATE_NEW;
attrs = FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH;
break;
default: break; /* silence gcc -Wswitch (not all enum values handled) */
}
fd = CreateFileW(fname->mn_val, acc, share, NULL, disp, attrs, NULL);
#else
fd = open(fname->mn_val, which & MDB_O_MASK, mode);
#endif
if (fd == INVALID_HANDLE_VALUE)
rc = ErrCode();
#ifndef _WIN32
else {
if (which != MDB_O_RDONLY && which != MDB_O_RDWR) {
/* Set CLOEXEC if we could not pass it to open() */
if (!MDB_CLOEXEC && (flags = fcntl(fd, F_GETFD)) != -1)
(void) fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
}
if (which == MDB_O_COPY && env->me_psize >= env->me_os_psize) {
/* This may require buffer alignment. There is no portable
* way to ask how much, so we require OS pagesize alignment.
*/
# ifdef F_NOCACHE /* __APPLE__ */
(void) fcntl(fd, F_NOCACHE, 1);
# elif defined O_DIRECT
/* open(...O_DIRECT...) would break on filesystems without
* O_DIRECT support (ITS#7682). Try to set it here instead.
*/
if ((flags = fcntl(fd, F_GETFL)) != -1)
(void) fcntl(fd, F_SETFL, flags | O_DIRECT);
# endif
}
}
#endif /* !_WIN32 */
*res = fd;
return rc;
}
#ifdef BROKEN_FDATASYNC
#include <sys/utsname.h>
#include <sys/vfs.h>
#endif
/** Further setup required for opening an LMDB environment
*/
static int ESECT
mdb_env_open2(MDB_env *env, int prev)
{
unsigned int flags = env->me_flags;
int i, newenv = 0, rc;
MDB_meta meta;
#ifdef _WIN32
/* See if we should use QueryLimited */
rc = GetVersion();
if ((rc & 0xff) > 5)
env->me_pidquery = MDB_PROCESS_QUERY_LIMITED_INFORMATION;
else
env->me_pidquery = PROCESS_QUERY_INFORMATION;
/* Grab functions we need from NTDLL */
if (!NtCreateSection) {
HMODULE h = GetModuleHandleW(L"NTDLL.DLL");
if (!h)
return MDB_PROBLEM;
NtClose = (NtCloseFunc *)GetProcAddress(h, "NtClose");
if (!NtClose)
return MDB_PROBLEM;
NtMapViewOfSection = (NtMapViewOfSectionFunc *)GetProcAddress(h, "NtMapViewOfSection");
if (!NtMapViewOfSection)
return MDB_PROBLEM;
NtCreateSection = (NtCreateSectionFunc *)GetProcAddress(h, "NtCreateSection");
if (!NtCreateSection)
return MDB_PROBLEM;
}
env->me_ovs = 0;
#endif /* _WIN32 */
#ifdef BROKEN_FDATASYNC
/* ext3/ext4 fdatasync is broken on some older Linux kernels.
* https://lkml.org/lkml/2012/9/3/83
* Kernels after 3.6-rc6 are known good.
* https://lkml.org/lkml/2012/9/10/556
* See if the DB is on ext3/ext4, then check for new enough kernel
* Kernels 2.6.32.60, 2.6.34.15, 3.2.30, and 3.5.4 are also known
* to be patched.
*/
{
struct statfs st;
fstatfs(env->me_fd, &st);
while (st.f_type == 0xEF53) {
struct utsname uts;
int i;
uname(&uts);
if (uts.release[0] < '3') {
if (!strncmp(uts.release, "2.6.32.", 7)) {
i = atoi(uts.release+7);
if (i >= 60)
break; /* 2.6.32.60 and newer is OK */
} else if (!strncmp(uts.release, "2.6.34.", 7)) {
i = atoi(uts.release+7);
if (i >= 15)
break; /* 2.6.34.15 and newer is OK */
}
} else if (uts.release[0] == '3') {
i = atoi(uts.release+2);
if (i > 5)
break; /* 3.6 and newer is OK */
if (i == 5) {
i = atoi(uts.release+4);
if (i >= 4)
break; /* 3.5.4 and newer is OK */
} else if (i == 2) {
i = atoi(uts.release+4);
if (i >= 30)
break; /* 3.2.30 and newer is OK */
}
} else { /* 4.x and newer is OK */
break;
}
env->me_flags |= MDB_FSYNCONLY;
break;
}
}
#endif
if ((i = mdb_env_read_header(env, prev, &meta)) != 0) {
if (i != ENOENT)
return i;
DPUTS("new mdbenv");
newenv = 1;
env->me_psize = env->me_os_psize;
if (env->me_psize > MAX_PAGESIZE)
env->me_psize = MAX_PAGESIZE;
memset(&meta, 0, sizeof(meta));
mdb_env_init_meta0(env, &meta);
meta.mm_mapsize = DEFAULT_MAPSIZE;
} else {
env->me_psize = meta.mm_psize;
}
/* Was a mapsize configured? */
if (!env->me_mapsize) {
env->me_mapsize = meta.mm_mapsize;
}
{
/* Make sure mapsize >= committed data size. Even when using
* mm_mapsize, which could be broken in old files (ITS#7789).
*/
mdb_size_t minsize = (meta.mm_last_pg + 1) * meta.mm_psize;
if (env->me_mapsize < minsize)
env->me_mapsize = minsize;
}
meta.mm_mapsize = env->me_mapsize;
if (newenv && !(flags & MDB_FIXEDMAP)) {
/* mdb_env_map() may grow the datafile. Write the metapages
* first, so the file will be valid if initialization fails.
* Except with FIXEDMAP, since we do not yet know mm_address.
* We could fill in mm_address later, but then a different
* program might end up doing that - one with a memory layout
* and map address which does not suit the main program.
*/
rc = mdb_env_init_meta(env, &meta);
if (rc)
return rc;
newenv = 0;
}
#ifdef _WIN32
/* For FIXEDMAP, make sure the file is non-empty before we attempt to map it */
if (newenv) {
char dummy = 0;
DWORD len;
rc = WriteFile(env->me_fd, &dummy, 1, &len, NULL);
if (!rc) {
rc = ErrCode();
return rc;
}
}
#endif
rc = mdb_env_map(env, (flags & MDB_FIXEDMAP) ? meta.mm_address : NULL);
if (rc)
return rc;
if (newenv) {
if (flags & MDB_FIXEDMAP)
meta.mm_address = env->me_map;
i = mdb_env_init_meta(env, &meta);
if (i != MDB_SUCCESS) {
return i;
}
}
if ((env->me_flags ^ env->me_metas[0]->mm_flags) & MDB_ENCRYPT)
return MDB_ENV_ENCRYPTION;
#if MDB_RPAGE_CACHE
if (!newenv && env->me_sumfunc) {
/* for checksums, check sum size from tail of page 0 */
char *ptr = env->me_map + env->me_psize;
unsigned short *u = (unsigned short *)(ptr - 2);
if (*u != env->me_sumsize)
return MDB_BAD_CHECKSUM;
}
#endif
env->me_maxfree_1pg = (env->me_psize - PAGEHDRSZ) / sizeof(pgno_t) - 1;
env->me_nodemax = (((env->me_psize - PAGEHDRSZ) / MDB_MINKEYS) & -2)
- sizeof(indx_t);
#if !(MDB_MAXKEYSIZE)
env->me_maxkey = env->me_nodemax - (NODESIZE + sizeof(MDB_db));
#endif
env->me_maxpg = env->me_mapsize / env->me_psize;
if (env->me_txns)
env->me_txns->mti_txnid = meta.mm_txnid;
#if MDB_DEBUG
{
MDB_meta *meta = mdb_env_pick_meta(env);
MDB_db *db = &meta->mm_dbs[MAIN_DBI];
DPRINTF(("opened database version %u, pagesize %u",
meta->mm_version, env->me_psize));
DPRINTF(("using meta page %d", (int) (meta->mm_txnid & 1)));
DPRINTF(("depth: %u", db->md_depth));
DPRINTF(("entries: %"Yu, db->md_entries));
DPRINTF(("branch pages: %"Yu, db->md_branch_pages));
DPRINTF(("leaf pages: %"Yu, db->md_leaf_pages));
DPRINTF(("overflow pages: %"Yu, db->md_overflow_pages));
DPRINTF(("root: %"Yu, db->md_root));
}
#endif
return MDB_SUCCESS;
}
/** Release a reader thread's slot in the reader lock table.
* This function is called automatically when a thread exits.
* @param[in] ptr This points to the slot in the reader lock table.
*/
static void
mdb_env_reader_dest(void *ptr)
{
MDB_reader *reader = ptr;
#ifndef _WIN32
if (reader->mr_pid == getpid()) /* catch pthread_exit() in child process */
#endif
/* We omit the mutex, so do this atomically (i.e. skip mr_txnid) */
reader->mr_pid = 0;
}
#ifdef _WIN32
/** Junk for arranging thread-specific callbacks on Windows. This is
* necessarily platform and compiler-specific. Windows supports up
* to 1088 keys. Let's assume nobody opens more than 64 environments
* in a single process, for now. They can override this if needed.
*/
#ifndef MAX_TLS_KEYS
#define MAX_TLS_KEYS 64
#endif
static pthread_key_t mdb_tls_keys[MAX_TLS_KEYS];
static int mdb_tls_nkeys;
static void NTAPI mdb_tls_callback(PVOID module, DWORD reason, PVOID ptr)
{
int i;
switch(reason) {
case DLL_PROCESS_ATTACH: break;
case DLL_THREAD_ATTACH: break;
case DLL_THREAD_DETACH:
for (i=0; i<mdb_tls_nkeys; i++) {
MDB_reader *r = pthread_getspecific(mdb_tls_keys[i]);
if (r) {
mdb_env_reader_dest(r);
}
}
break;
case DLL_PROCESS_DETACH: break;
}
}
#ifdef __GNUC__
#ifdef _WIN64
const PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
#else
PIMAGE_TLS_CALLBACK mdb_tls_cbp __attribute__((section (".CRT$XLB"))) = mdb_tls_callback;
#endif
#else
#ifdef _WIN64
/* Force some symbol references.
* _tls_used forces the linker to create the TLS directory if not already done
* mdb_tls_cbp prevents whole-program-optimizer from dropping the symbol.
*/
#pragma comment(linker, "/INCLUDE:_tls_used")
#pragma comment(linker, "/INCLUDE:mdb_tls_cbp")
#pragma const_seg(".CRT$XLB")
extern const PIMAGE_TLS_CALLBACK mdb_tls_cbp;
const PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
#pragma const_seg()
#else /* _WIN32 */
#pragma comment(linker, "/INCLUDE:__tls_used")
#pragma comment(linker, "/INCLUDE:_mdb_tls_cbp")
#pragma data_seg(".CRT$XLB")
PIMAGE_TLS_CALLBACK mdb_tls_cbp = mdb_tls_callback;
#pragma data_seg()
#endif /* WIN 32/64 */
#endif /* !__GNUC__ */
#endif
/** Downgrade the exclusive lock on the region back to shared */
static int ESECT
mdb_env_share_locks(MDB_env *env, int *excl)
{
int rc = 0;
#ifdef _WIN32
{
OVERLAPPED ov;
/* First acquire a shared lock. The Unlock will
* then release the existing exclusive lock.
*/
memset(&ov, 0, sizeof(ov));
if (!LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
rc = ErrCode();
} else {
UnlockFile(env->me_lfd, 0, 0, 1, 0);
*excl = 0;
}
}
#else
{
struct flock lock_info;
/* The shared lock replaces the existing lock */
memset((void *)&lock_info, 0, sizeof(lock_info));
lock_info.l_type = F_RDLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = 0;
lock_info.l_len = 1;
while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
(rc = ErrCode()) == EINTR) ;
*excl = rc ? -1 : 0; /* error may mean we lost the lock */
}
#endif
return rc;
}
/** Try to get exclusive lock, otherwise shared.
* Maintain *excl = -1: no/unknown lock, 0: shared, 1: exclusive.
*/
static int ESECT
mdb_env_excl_lock(MDB_env *env, int *excl)
{
int rc = 0;
#ifdef _WIN32
if (LockFile(env->me_lfd, 0, 0, 1, 0)) {
*excl = 1;
} else {
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
if (LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov)) {
*excl = 0;
} else {
rc = ErrCode();
}
}
#else
struct flock lock_info;
memset((void *)&lock_info, 0, sizeof(lock_info));
lock_info.l_type = F_WRLCK;
lock_info.l_whence = SEEK_SET;
lock_info.l_start = 0;
lock_info.l_len = 1;
while ((rc = fcntl(env->me_lfd, F_SETLK, &lock_info)) &&
(rc = ErrCode()) == EINTR) ;
if (!rc) {
*excl = 1;
} else
# ifndef MDB_USE_POSIX_MUTEX
if (*excl < 0) /* always true when MDB_USE_POSIX_MUTEX */
# endif
{
lock_info.l_type = F_RDLCK;
while ((rc = fcntl(env->me_lfd, F_SETLKW, &lock_info)) &&
(rc = ErrCode()) == EINTR) ;
if (rc == 0)
*excl = 0;
}
#endif
return rc;
}
#ifdef MDB_USE_HASH
/*
* hash_64 - 64 bit Fowler/Noll/Vo-0 FNV-1a hash code
*
* @(#) $Revision: 5.1 $
* @(#) $Id: hash_64a.c,v 5.1 2009/06/30 09:01:38 chongo Exp $
* @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_64a.c,v $
*
* http://www.isthe.com/chongo/tech/comp/fnv/index.html
*
***
*
* Please do not copyright this code. This code is in the public domain.
*
* LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
* EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*
* By:
* chongo <Landon Curt Noll> /\oo/\
* http://www.isthe.com/chongo/
*
* Share and Enjoy! :-)
*/
/** perform a 64 bit Fowler/Noll/Vo FNV-1a hash on a buffer
* @param[in] val value to hash
* @param[in] len length of value
* @return 64 bit hash
*/
static mdb_hash_t
mdb_hash(const void *val, size_t len)
{
const unsigned char *s = (const unsigned char *) val, *end = s + len;
mdb_hash_t hval = 0xcbf29ce484222325ULL;
/*
* FNV-1a hash each octet of the buffer
*/
while (s < end) {
hval = (hval ^ *s++) * 0x100000001b3ULL;
}
/* return our new hash value */
return hval;
}
/** Hash the string and output the encoded hash.
* This uses modified RFC1924 Ascii85 encoding to accommodate systems with
* very short name limits. We don't care about the encoding being reversible,
* we just want to preserve as many bits of the input as possible in a
* small printable string.
* @param[in] str string to hash
* @param[out] encbuf an array of 11 chars to hold the hash
*/
static const char mdb_a85[]= "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
static void ESECT
mdb_pack85(unsigned long long l, char *out)
{
int i;
for (i=0; i<10 && l; i++) {
*out++ = mdb_a85[l % 85];
l /= 85;
}
*out = '\0';
}
/** Init #MDB_env.me_mutexname[] except the char which #MUTEXNAME() will set.
* Changes to this code must be reflected in #MDB_LOCK_FORMAT.
*/
static void ESECT
mdb_env_mname_init(MDB_env *env)
{
char *nm = env->me_mutexname;
strcpy(nm, MUTEXNAME_PREFIX);
mdb_pack85(env->me_txns->mti_mutexid, nm + sizeof(MUTEXNAME_PREFIX));
}
/** Return env->me_mutexname after filling in ch ('r'/'w') for convenience */
#define MUTEXNAME(env, ch) ( \
(void) ((env)->me_mutexname[sizeof(MUTEXNAME_PREFIX)-1] = (ch)), \
(env)->me_mutexname)
#endif
/** Open and/or initialize the lock region for the environment.
* @param[in] env The LMDB environment.
* @param[in] fname Filename + scratch area, from #mdb_fname_init().
* @param[in] mode The Unix permissions for the file, if we create it.
* @param[in,out] excl In -1, out lock type: -1 none, 0 shared, 1 exclusive
* @return 0 on success, non-zero on failure.
*/
static int ESECT
mdb_env_setup_locks(MDB_env *env, MDB_name *fname, int mode, int *excl)
{
#ifdef _WIN32
# define MDB_ERRCODE_ROFS ERROR_WRITE_PROTECT
#else
# define MDB_ERRCODE_ROFS EROFS
#endif
#ifdef MDB_USE_SYSV_SEM
int semid;
union semun semu;
#endif
int rc;
MDB_OFF_T size, rsize;
rc = mdb_fopen(env, fname, MDB_O_LOCKS, mode, &env->me_lfd);
if (rc) {
/* Omit lockfile if read-only env on read-only filesystem */
if (rc == MDB_ERRCODE_ROFS && (env->me_flags & MDB_RDONLY)) {
return MDB_SUCCESS;
}
goto fail;
}
if (!(env->me_flags & MDB_NOTLS)) {
rc = pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
if (rc)
goto fail;
env->me_flags |= MDB_ENV_TXKEY;
#ifdef _WIN32
/* Windows TLS callbacks need help finding their TLS info. */
if (mdb_tls_nkeys >= MAX_TLS_KEYS) {
rc = MDB_TLS_FULL;
goto fail;
}
mdb_tls_keys[mdb_tls_nkeys++] = env->me_txkey;
#endif
}
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
if ((rc = mdb_env_excl_lock(env, excl))) goto fail;
#ifdef _WIN32
size = GetFileSize(env->me_lfd, NULL);
#else
size = lseek(env->me_lfd, 0, SEEK_END);
if (size == -1) goto fail_errno;
#endif
rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
if (size < rsize && *excl > 0) {
#ifdef _WIN32
if (SetFilePointer(env->me_lfd, rsize, NULL, FILE_BEGIN) != (DWORD)rsize
|| !SetEndOfFile(env->me_lfd))
goto fail_errno;
#else
if (ftruncate(env->me_lfd, rsize) != 0) goto fail_errno;
#endif
} else {
rsize = size;
size = rsize - sizeof(MDB_txninfo);
env->me_maxreaders = size/sizeof(MDB_reader) + 1;
}
{
#ifdef _WIN32
HANDLE mh;
mh = CreateFileMapping(env->me_lfd, NULL, PAGE_READWRITE,
0, 0, NULL);
if (!mh) goto fail_errno;
env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
CloseHandle(mh);
if (!env->me_txns) goto fail_errno;
#else
void *m = mmap(NULL, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
env->me_lfd, 0);
if (m == MAP_FAILED) goto fail_errno;
env->me_txns = m;
#endif
}
if (*excl > 0) {
#ifdef _WIN32
BY_HANDLE_FILE_INFORMATION stbuf;
struct {
DWORD volume;
DWORD nhigh;
DWORD nlow;
} idbuf;
if (!mdb_sec_inited) {
InitializeSecurityDescriptor(&mdb_null_sd,
SECURITY_DESCRIPTOR_REVISION);
SetSecurityDescriptorDacl(&mdb_null_sd, TRUE, 0, FALSE);
mdb_all_sa.nLength = sizeof(SECURITY_ATTRIBUTES);
mdb_all_sa.bInheritHandle = FALSE;
mdb_all_sa.lpSecurityDescriptor = &mdb_null_sd;
mdb_sec_inited = 1;
}
if (!GetFileInformationByHandle(env->me_lfd, &stbuf)) goto fail_errno;
idbuf.volume = stbuf.dwVolumeSerialNumber;
idbuf.nhigh = stbuf.nFileIndexHigh;
idbuf.nlow = stbuf.nFileIndexLow;
env->me_txns->mti_mutexid = mdb_hash(&idbuf, sizeof(idbuf));
mdb_env_mname_init(env);
env->me_rmutex = CreateMutexA(&mdb_all_sa, FALSE, MUTEXNAME(env, 'r'));
if (!env->me_rmutex) goto fail_errno;
env->me_wmutex = CreateMutexA(&mdb_all_sa, FALSE, MUTEXNAME(env, 'w'));
if (!env->me_wmutex) goto fail_errno;
#elif defined(MDB_USE_POSIX_SEM)
struct stat stbuf;
struct {
dev_t dev;
ino_t ino;
} idbuf;
#if defined(__NetBSD__)
#define MDB_SHORT_SEMNAMES 1 /* limited to 14 chars */
#endif
if (fstat(env->me_lfd, &stbuf)) goto fail_errno;
memset(&idbuf, 0, sizeof(idbuf));
idbuf.dev = stbuf.st_dev;
idbuf.ino = stbuf.st_ino;
env->me_txns->mti_mutexid = mdb_hash(&idbuf, sizeof(idbuf))
#ifdef MDB_SHORT_SEMNAMES
/* Max 9 base85-digits. We truncate here instead of in
* mdb_env_mname_init() to keep the latter portable.
*/
% ((mdb_hash_t)85*85*85*85*85*85*85*85*85)
#endif
;
mdb_env_mname_init(env);
/* Clean up after a previous run, if needed: Try to
* remove both semaphores before doing anything else.
*/
sem_unlink(MUTEXNAME(env, 'r'));
sem_unlink(MUTEXNAME(env, 'w'));
env->me_rmutex = sem_open(MUTEXNAME(env, 'r'), O_CREAT|O_EXCL, mode, 1);
if (env->me_rmutex == SEM_FAILED) goto fail_errno;
env->me_wmutex = sem_open(MUTEXNAME(env, 'w'), O_CREAT|O_EXCL, mode, 1);
if (env->me_wmutex == SEM_FAILED) goto fail_errno;
#elif defined(MDB_USE_SYSV_SEM)
unsigned short vals[2] = {1, 1};
key_t key = ftok(fname->mn_val, 'M'); /* fname is lockfile path now */
if (key == -1)
goto fail_errno;
semid = semget(key, 2, (mode & 0777) | IPC_CREAT);
if (semid < 0)
goto fail_errno;
semu.array = vals;
if (semctl(semid, 0, SETALL, semu) < 0)
goto fail_errno;
env->me_txns->mti_semid = semid;
env->me_txns->mti_rlocked = 0;
env->me_txns->mti_wlocked = 0;
#else /* MDB_USE_POSIX_MUTEX: */
pthread_mutexattr_t mattr;
/* Solaris needs this before initing a robust mutex. Otherwise
* it may skip the init and return EBUSY "seems someone already
* inited" or EINVAL "it was inited differently".
*/
memset(env->me_txns->mti_rmutex, 0, sizeof(*env->me_txns->mti_rmutex));
memset(env->me_txns->mti_wmutex, 0, sizeof(*env->me_txns->mti_wmutex));
if ((rc = pthread_mutexattr_init(&mattr)) != 0)
goto fail;
rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
#ifdef MDB_ROBUST_SUPPORTED
if (!rc) rc = pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
#endif
if (!rc) rc = pthread_mutex_init(env->me_txns->mti_rmutex, &mattr);
if (!rc) rc = pthread_mutex_init(env->me_txns->mti_wmutex, &mattr);
pthread_mutexattr_destroy(&mattr);
if (rc)
goto fail;
#endif /* _WIN32 || ... */
env->me_txns->mti_magic = MDB_MAGIC;
env->me_txns->mti_format = MDB_LOCK_FORMAT;
env->me_txns->mti_txnid = 0;
env->me_txns->mti_numreaders = 0;
} else {
#ifdef MDB_USE_SYSV_SEM
struct semid_ds buf;
#endif
if (env->me_txns->mti_magic != MDB_MAGIC) {
DPUTS("lock region has invalid magic");
rc = MDB_INVALID;
goto fail;
}
if (env->me_txns->mti_format != MDB_LOCK_FORMAT) {
DPRINTF(("lock region has format+version 0x%x, expected 0x%x",
env->me_txns->mti_format, MDB_LOCK_FORMAT));
rc = MDB_VERSION_MISMATCH;
goto fail;
}
rc = ErrCode();
if (rc && rc != EACCES && rc != EAGAIN) {
goto fail;
}
#ifdef _WIN32
mdb_env_mname_init(env);
env->me_rmutex = OpenMutexA(SYNCHRONIZE, FALSE, MUTEXNAME(env, 'r'));
if (!env->me_rmutex) goto fail_errno;
env->me_wmutex = OpenMutexA(SYNCHRONIZE, FALSE, MUTEXNAME(env, 'w'));
if (!env->me_wmutex) goto fail_errno;
#elif defined(MDB_USE_POSIX_SEM)
mdb_env_mname_init(env);
env->me_rmutex = sem_open(MUTEXNAME(env, 'r'), 0);
if (env->me_rmutex == SEM_FAILED) goto fail_errno;
env->me_wmutex = sem_open(MUTEXNAME(env, 'w'), 0);
if (env->me_wmutex == SEM_FAILED) goto fail_errno;
#elif defined(MDB_USE_SYSV_SEM)
semid = env->me_txns->mti_semid;
semu.buf = &buf;
/* check for read access */
if (semctl(semid, 0, IPC_STAT, semu) < 0)
goto fail_errno;
/* check for write access */
if (semctl(semid, 0, IPC_SET, semu) < 0)
goto fail_errno;
#endif
}
#ifdef MDB_USE_SYSV_SEM
env->me_rmutex->semid = semid;
env->me_wmutex->semid = semid;
env->me_rmutex->semnum = 0;
env->me_wmutex->semnum = 1;
env->me_rmutex->locked = &env->me_txns->mti_rlocked;
env->me_wmutex->locked = &env->me_txns->mti_wlocked;
#endif
return MDB_SUCCESS;
fail_errno:
rc = ErrCode();
fail:
return rc;
}
#ifdef MDB_TEST
#if MDB_RPAGE_CACHE
/** Trivial encryption for testing */
static void ESECT
mdb_enctest(const MDB_val *src, MDB_val *dst, const MDB_val *key, int encdec)
{
mdb_size_t *sptr = src->mv_data, *dptr = dst->mv_data;
mdb_size_t x=*(mdb_size_t*)key[0].mv_data, v=*(mdb_size_t*)key[1].mv_data;
int i, len = dst->mv_size / sizeof(mdb_size_t);
for (i = 0; i < len; i++)
x += v += i + sptr[i] + (dptr[i] = sptr[i] ^ x);
}
#endif /* MDB_RPAGE_CACHE */
/** Add #mdb_env_open() flags from environment variable $LMDB_FLAGS.
*
* Supports the normal flags plus 'e' = trivial encryption for testing.
*/
static int ESECT
mdb_env_envflags(MDB_env *env)
{
static const char names[] = "ace" "fhi" "lmn" "rst" "vw";
static const unsigned f[] = {
/*a*/ MDB_MAPASYNC, /*c*/ MDB_REMAP_CHUNKS, /*e*/ MDB_ENCRYPT,
/*f*/ MDB_FIXEDMAP, /*h*/ MDB_NORDAHEAD, /*i*/ MDB_NOMEMINIT,
/*l*/ MDB_NOLOCK, /*m*/ MDB_NOMETASYNC, /*n*/ MDB_NOSUBDIR,
/*r*/ MDB_RDONLY, /*s*/ MDB_NOSYNC, /*t*/ MDB_NOTLS,
/*v*/ MDB_PREVSNAPSHOT, /*w*/ MDB_WRITEMAP,
};
unsigned flags = 0;
const char *s, *opts = getenv("LMDB_FLAGS");
if (opts) {
for (; *opts; opts++) {
if ((s = strchr(names, *opts)) == NULL)
return EINVAL;
flags |= f[s - names];
}
if (flags & MDB_ENCRYPT) {
#if MDB_RPAGE_CACHE
if (!env->me_encfunc) {
static mdb_size_t k = (MDB_SIZE_MAX/67*73) | 1;
MDB_val key = {sizeof(k), &k};
int rc;
rc = mdb_env_set_encrypt(env, mdb_enctest, &key, 0);
if (rc)
return rc;
}
#else
return EINVAL;
#endif
}
env->me_flags |= flags;
}
return MDB_SUCCESS;
}
#else
#define mdb_env_envflags(env) MDB_SUCCESS
#endif /* MDB_TEST */
/** Only a subset of the @ref mdb_env flags can be changed
* at runtime. Changing other flags requires closing the
* environment and re-opening it with the new flags.
*/
#define CHANGEABLE (MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC|MDB_NOMEMINIT)
#define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY| \
MDB_WRITEMAP|MDB_NOTLS|MDB_NOLOCK|MDB_NORDAHEAD|MDB_PREVSNAPSHOT|MDB_REMAP_CHUNKS)
#define EXPOSED (CHANGEABLE|CHANGELESS | MDB_ENCRYPT)
#if VALID_FLAGS & PERSISTENT_FLAGS & EXPOSED
# error "Persistent DB flags & env flags overlap, but both go in mm_flags"
#endif
int ESECT
mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
{
int rc, excl = -1;
MDB_name fname;
if (env->me_fd!=INVALID_HANDLE_VALUE || (flags & ~(CHANGEABLE|CHANGELESS)))
return EINVAL;
if ((rc = mdb_env_envflags(env)) != MDB_SUCCESS)
return rc;
flags |= env->me_flags;
if (MDB_REMAPPING(0)) /* if we always remap chunks */
flags |= MDB_REMAP_CHUNKS;
if (MDB_REMAPPING(flags)) {
/* silently ignore WRITEMAP with REMAP_CHUNKS */
flags &= ~MDB_WRITEMAP;
#if (MDB_RPAGE_CACHE) & 2
/* TEST: silently ignore FIXEDMAP, so mtest*.c will work */
flags &= ~MDB_FIXEDMAP;
#else
/* cannot support FIXEDMAP */
if (flags & MDB_FIXEDMAP)
return EINVAL;
#endif
}
rc = mdb_fname_init(path, flags, &fname);
if (rc)
return rc;
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(flags)) {
#ifdef _WIN32
env->me_rpmutex = CreateMutex(NULL, FALSE, NULL);
if (!env->me_rpmutex) {
rc = ErrCode();
goto leave;
}
#else
rc = pthread_mutex_init(&env->me_rpmutex, NULL);
if (rc)
goto leave;
#endif
}
#endif
#ifndef _WIN32
{
struct stat st;
rc = stat(path, &st);
if (rc)
return ErrCode();
flags &= ~MDB_RAWPART;
if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode))
flags |= MDB_RAWPART | MDB_NOSUBDIR;
}
#endif
flags |= MDB_ENV_ACTIVE; /* tell mdb_env_close_active() to clean up */
if (flags & MDB_RDONLY) {
/* silently ignore WRITEMAP when we're only getting read access */
flags &= ~MDB_WRITEMAP;
} else {
/* WRITEMAP has a dummy element to match dirty_room = 1 */
size_t dl_size = (flags & MDB_WRITEMAP) ? 2 : MDB_IDL_UM_SIZE;
if (!((env->me_free_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX)) &&
(env->me_dirty_list = calloc(dl_size, sizeof(MDB_ID2)))))
rc = ENOMEM;
if (env->me_dirty_list && !(env->me_dirty_nump = malloc(dl_size * sizeof(int))))
rc = ENOMEM;
}
env->me_flags = flags;
if (rc)
goto leave;
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(flags))
{
env->me_rpages = malloc(MDB_ERPAGE_SIZE * sizeof(MDB_ID3));
if (!env->me_rpages) {
rc = ENOMEM;
goto leave;
}
env->me_rpages[0].mid = 0;
env->me_rpcheck = MDB_ERPAGE_SIZE/2;
}
#endif
env->me_path = strdup(path);
env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
env->me_dbflags = calloc(env->me_maxdbs, sizeof(uint16_t));
env->me_dbiseqs = calloc(env->me_maxdbs, sizeof(unsigned int));
if (!(env->me_dbxs && env->me_path && env->me_dbflags && env->me_dbiseqs)) {
rc = ENOMEM;
goto leave;
}
env->me_dbxs[FREE_DBI].md_cmp = mdb_cmp_long; /* aligned MDB_INTEGERKEY */
/* For RDONLY, get lockfile after we know datafile exists */
if (!(flags & (MDB_RDONLY|MDB_NOLOCK))) {
rc = mdb_env_setup_locks(env, &fname, mode, &excl);
if (rc)
goto leave;
if ((flags & MDB_PREVSNAPSHOT) && !excl) {
rc = EAGAIN;
goto leave;
}
}
rc = mdb_fopen(env, &fname,
(flags & MDB_RDONLY) ? MDB_O_RDONLY : MDB_O_RDWR,
mode, &env->me_fd);
if (rc)
goto leave;
#ifdef _WIN32
rc = mdb_fopen(env, &fname, MDB_O_OVERLAPPED, mode, &env->me_ovfd);
if (rc)
goto leave;
#endif
if ((flags & (MDB_RDONLY|MDB_NOLOCK)) == MDB_RDONLY) {
rc = mdb_env_setup_locks(env, &fname, mode, &excl);
if (rc)
goto leave;
}
if ((rc = mdb_env_open2(env, flags & MDB_PREVSNAPSHOT)) == MDB_SUCCESS) {
/* Synchronous fd for meta writes. Needed even with
* MDB_NOSYNC/MDB_NOMETASYNC, in case these get reset.
*/
rc = mdb_fopen(env, &fname, MDB_O_META, mode, &env->me_mfd);
if (rc)
goto leave;
DPRINTF(("opened dbenv %p", (void *) env));
if (excl > 0 && !(flags & MDB_PREVSNAPSHOT)) {
rc = mdb_env_share_locks(env, &excl);
if (rc)
goto leave;
}
if (!(flags & MDB_RDONLY)) {
MDB_txn *txn;
int tsize = sizeof(MDB_txn), size = tsize + env->me_maxdbs *
(sizeof(MDB_db)+sizeof(MDB_cursor *)+sizeof(unsigned int)+1);
if ((env->me_pbuf = calloc(1, env->me_psize)) &&
(txn = calloc(1, size)))
{
txn->mt_dbs = (MDB_db *)((char *)txn + tsize);
txn->mt_cursors = (MDB_cursor **)(txn->mt_dbs + env->me_maxdbs);
txn->mt_dbiseqs = (unsigned int *)(txn->mt_cursors + env->me_maxdbs);
txn->mt_dbflags = (unsigned char *)(txn->mt_dbiseqs + env->me_maxdbs);
txn->mt_env = env;
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags)) {
txn->mt_rpages = malloc(MDB_TRPAGE_SIZE * sizeof(MDB_ID3));
if (!txn->mt_rpages) {
free(txn);
rc = ENOMEM;
goto leave;
}
txn->mt_rpages[0].mid = 0;
txn->mt_rpcheck = MDB_TRPAGE_SIZE/2;
}
#endif
txn->mt_dbxs = env->me_dbxs;
txn->mt_flags = MDB_TXN_FINISHED;
env->me_txn0 = txn;
} else {
rc = ENOMEM;
}
}
}
leave:
if (rc) {
mdb_env_close_active(env, excl);
}
mdb_fname_destroy(fname);
return rc;
}
/** When #MDB_ENV_ACTIVE: Clear #mdb_env_open()ed resources, release readers */
static void ESECT
mdb_env_close_active(MDB_env *env, int excl)
{
int i;
if (!(env->me_flags & MDB_ENV_ACTIVE))
return;
/* Doing this here since me_dbxs may not exist during mdb_env_close */
if (env->me_dbxs) {
for (i = env->me_maxdbs; --i >= CORE_DBS; )
free(env->me_dbxs[i].md_name.mv_data);
free(env->me_dbxs);
}
free(env->me_pbuf);
free(env->me_dbiseqs);
free(env->me_dbflags);
free(env->me_path);
free(env->me_dirty_list);
free(env->me_dirty_nump);
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags)) {
if (env->me_txn0 && env->me_txn0->mt_rpages)
free(env->me_txn0->mt_rpages);
if (env->me_rpages) {
MDB_ID3L el = env->me_rpages;
unsigned int x;
for (x=1; x<=el[0].mid; x++)
munmap(el[x].mptr, el[x].mcnt * env->me_psize);
free(el);
}
}
#endif
free(env->me_txn0);
mdb_midl_free(env->me_free_pgs);
if (env->me_flags & MDB_ENV_TXKEY) {
pthread_key_delete(env->me_txkey);
#ifdef _WIN32
/* Delete our key from the global list */
for (i=0; i<mdb_tls_nkeys; i++)
if (mdb_tls_keys[i] == env->me_txkey) {
mdb_tls_keys[i] = mdb_tls_keys[mdb_tls_nkeys-1];
mdb_tls_nkeys--;
break;
}
#endif
}
if (env->me_map) {
if (MDB_REMAPPING(env->me_flags))
munmap(env->me_map, NUM_METAS*env->me_psize);
else
munmap(env->me_map, env->me_mapsize);
}
if (env->me_mfd != INVALID_HANDLE_VALUE)
(void) close(env->me_mfd);
#ifdef _WIN32
if (env->me_ovs > 0) {
for (i = 0; i < env->me_ovs; i++) {
CloseHandle(env->me_ov[i].hEvent);
}
free(env->me_ov);
}
if (env->me_ovfd != INVALID_HANDLE_VALUE)
(void) close(env->me_ovfd);
#endif
if (env->me_fd != INVALID_HANDLE_VALUE)
(void) close(env->me_fd);
if (env->me_txns) {
MDB_PID_T pid = getpid();
/* Clearing readers is done in this function because
* me_txkey with its destructor must be disabled first.
*
* We skip the the reader mutex, so we touch only
* data owned by this process (me_close_readers and
* our readers), and clear each reader atomically.
*/
for (i = env->me_close_readers; --i >= 0; )
if (env->me_txns->mti_readers[i].mr_pid == pid)
env->me_txns->mti_readers[i].mr_pid = 0;
#ifdef _WIN32
if (env->me_rmutex) {
CloseHandle(env->me_rmutex);
if (env->me_wmutex) CloseHandle(env->me_wmutex);
}
/* Windows automatically destroys the mutexes when
* the last handle closes.
*/
#elif defined(MDB_USE_POSIX_SEM)
if (env->me_rmutex != SEM_FAILED) {
sem_close(env->me_rmutex);
if (env->me_wmutex != SEM_FAILED)
sem_close(env->me_wmutex);
/* If we have the filelock: If we are the
* only remaining user, clean up semaphores.
*/
if (excl == 0)
mdb_env_excl_lock(env, &excl);
if (excl > 0) {
sem_unlink(MUTEXNAME(env, 'r'));
sem_unlink(MUTEXNAME(env, 'w'));
}
}
#elif defined(MDB_USE_SYSV_SEM)
if (env->me_rmutex->semid != -1) {
/* If we have the filelock: If we are the
* only remaining user, clean up semaphores.
*/
if (excl == 0)
mdb_env_excl_lock(env, &excl);
if (excl > 0)
semctl(env->me_rmutex->semid, 0, IPC_RMID);
}
#elif defined(MDB_ROBUST_SUPPORTED)
/* If we have the filelock: If we are the
* only remaining user, clean up robust
* mutexes.
*/
if (excl == 0)
mdb_env_excl_lock(env, &excl);
if (excl > 0) {
pthread_mutex_destroy(env->me_txns->mti_rmutex);
pthread_mutex_destroy(env->me_txns->mti_wmutex);
}
#endif
munmap((void *)env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
}
if (env->me_lfd != INVALID_HANDLE_VALUE) {
#ifdef _WIN32
if (excl >= 0) {
/* Unlock the lockfile. Windows would have unlocked it
* after closing anyway, but not necessarily at once.
*/
UnlockFile(env->me_lfd, 0, 0, 1, 0);
}
#endif
(void) close(env->me_lfd);
}
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(env->me_flags))
{
#ifdef _WIN32
if (env->me_fmh) CloseHandle(env->me_fmh);
if (env->me_rpmutex) CloseHandle(env->me_rpmutex);
#else
pthread_mutex_destroy(&env->me_rpmutex);
#endif
}
#endif
env->me_flags &= ~(MDB_ENV_ACTIVE|MDB_ENV_TXKEY);
}
void ESECT
mdb_env_close(MDB_env *env)
{
MDB_page *dp;
if (env == NULL)
return;
VGMEMP_DESTROY(env);
while ((dp = env->me_dpages) != NULL) {
VGMEMP_DEFINED(&dp->mp_next, sizeof(dp->mp_next));
env->me_dpages = dp->mp_next;
free(dp);
}
mdb_env_close_active(env, 0);
#if MDB_RPAGE_CACHE
free(env->me_enckey.mv_data);
#endif
free(env);
}
/** Compare two items pointing at aligned #mdb_size_t's */
static int
mdb_cmp_long(const MDB_val *a, const MDB_val *b)
{
return (*(mdb_size_t *)a->mv_data < *(mdb_size_t *)b->mv_data) ? -1 :
*(mdb_size_t *)a->mv_data > *(mdb_size_t *)b->mv_data;
}
/** Compare two items pointing at aligned unsigned int's.
*
* This is also set as #MDB_INTEGERDUP|#MDB_DUPFIXED's #MDB_dbx.%md_dcmp,
* but #mdb_cmp_clong() is called instead if the data type is #mdb_size_t.
*/
static int
mdb_cmp_int(const MDB_val *a, const MDB_val *b)
{
return (*(unsigned int *)a->mv_data < *(unsigned int *)b->mv_data) ? -1 :
*(unsigned int *)a->mv_data > *(unsigned int *)b->mv_data;
}
/** Compare two items pointing at unsigned ints of unknown alignment.
* Nodes and keys are guaranteed to be 2-byte aligned.
*/
static int
mdb_cmp_cint(const MDB_val *a, const MDB_val *b)
{
#if BYTE_ORDER == LITTLE_ENDIAN
unsigned short *u, *c;
int x;
u = (unsigned short *) ((char *) a->mv_data + a->mv_size);
c = (unsigned short *) ((char *) b->mv_data + a->mv_size);
do {
x = *--u - *--c;
} while(!x && u > (unsigned short *)a->mv_data);
return x;
#else
unsigned short *u, *c, *end;
int x;
end = (unsigned short *) ((char *) a->mv_data + a->mv_size);
u = (unsigned short *)a->mv_data;
c = (unsigned short *)b->mv_data;
do {
x = *u++ - *c++;
} while(!x && u < end);
return x;
#endif
}
/** Compare two items lexically */
static int
mdb_cmp_memn(const MDB_val *a, const MDB_val *b)
{
int diff;
ssize_t len_diff;
unsigned int len;
len = a->mv_size;
len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
if (len_diff > 0) {
len = b->mv_size;
len_diff = 1;
}
diff = memcmp(a->mv_data, b->mv_data, len);
return diff ? diff : len_diff<0 ? -1 : len_diff;
}
/** Compare two items in reverse byte order */
static int
mdb_cmp_memnr(const MDB_val *a, const MDB_val *b)
{
const unsigned char *p1, *p2, *p1_lim;
ssize_t len_diff;
int diff;
p1_lim = (const unsigned char *)a->mv_data;
p1 = (const unsigned char *)a->mv_data + a->mv_size;
p2 = (const unsigned char *)b->mv_data + b->mv_size;
len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
if (len_diff > 0) {
p1_lim += len_diff;
len_diff = 1;
}
while (p1 > p1_lim) {
diff = *--p1 - *--p2;
if (diff)
return diff;
}
return len_diff<0 ? -1 : len_diff;
}
/** Search for key within a page, using binary search.
* Returns the smallest entry larger or equal to the key.
* If exactp is non-null, stores whether the found entry was an exact match
* in *exactp (1 or 0).
* Updates the cursor index with the index of the found entry.
* If no entry larger or equal to the key is found, returns NULL.
*/
static MDB_node *
mdb_node_search(MDB_cursor *mc, MDB_val *key, int *exactp)
{
unsigned int i = 0, nkeys;
int low, high;
int rc = 0;
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_node *node = NULL;
MDB_val nodekey;
MDB_cmp_func *cmp;
DKBUF;
nkeys = NUMKEYS(mp);
DPRINTF(("searching %u keys in %s %spage %"Yu,
nkeys, IS_LEAF(mp) ? "leaf" : "branch", IS_SUBP(mp) ? "sub-" : "",
mdb_dbg_pgno(mp)));
low = IS_LEAF(mp) ? 0 : 1;
high = nkeys - 1;
cmp = mc->mc_dbx->md_cmp;
/* Branch pages have no data, so if using integer keys,
* alignment is guaranteed. Use faster mdb_cmp_int.
*/
if (cmp == mdb_cmp_cint && IS_BRANCH(mp)) {
if (NODEPTR(mp, 1)->mn_ksize == sizeof(mdb_size_t))
cmp = mdb_cmp_long;
else
cmp = mdb_cmp_int;
}
if (IS_LEAF2(mp)) {
nodekey.mv_size = mc->mc_db->md_pad;
node = NODEPTR(mp, 0); /* fake */
while (low <= high) {
i = (low + high) >> 1;
nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
rc = cmp(key, &nodekey);
DPRINTF(("found leaf index %u [%s], rc = %i",
i, DKEY(&nodekey), rc));
if (rc == 0)
break;
if (rc > 0)
low = i + 1;
else
high = i - 1;
}
} else {
while (low <= high) {
i = (low + high) >> 1;
node = NODEPTR(mp, i);
nodekey.mv_size = NODEKSZ(node);
nodekey.mv_data = NODEKEY(node);
rc = cmp(key, &nodekey);
#if MDB_DEBUG
if (IS_LEAF(mp))
DPRINTF(("found leaf index %u [%s], rc = %i",
i, DKEY(&nodekey), rc));
else
DPRINTF(("found branch index %u [%s -> %"Yu"], rc = %i",
i, DKEY(&nodekey), NODEPGNO(node), rc));
#endif
if (rc == 0)
break;
if (rc > 0)
low = i + 1;
else
high = i - 1;
}
}
if (rc > 0) { /* Found entry is less than the key. */
i++; /* Skip to get the smallest entry larger than key. */
if (!IS_LEAF2(mp))
node = NODEPTR(mp, i);
}
if (exactp)
*exactp = (rc == 0 && nkeys > 0);
/* store the key index */
mc->mc_ki[mc->mc_top] = i;
if (i >= nkeys)
/* There is no entry larger or equal to the key. */
return NULL;
/* nodeptr is fake for LEAF2 */
return node;
}
#if 0
static void
mdb_cursor_adjust(MDB_cursor *mc, func)
{
MDB_cursor *m2;
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
if (m2->mc_pg[m2->mc_top] == mc->mc_pg[mc->mc_top]) {
func(mc, m2);
}
}
}
#endif
/** Pop a page off the top of the cursor's stack. */
static void
mdb_cursor_pop(MDB_cursor *mc)
{
if (mc->mc_snum) {
DPRINTF(("popping page %"Yu" off db %d cursor %p",
mc->mc_pg[mc->mc_top]->mp_pgno, DDBI(mc), (void *) mc));
mc->mc_snum--;
if (mc->mc_snum) {
mc->mc_top--;
} else {
mc->mc_flags &= ~C_INITIALIZED;
}
}
}
/** Push a page onto the top of the cursor's stack.
* Set #MDB_TXN_ERROR on failure.
*/
static int
mdb_cursor_push(MDB_cursor *mc, MDB_page *mp)
{
DPRINTF(("pushing page %"Yu" on db %d cursor %p", mp->mp_pgno,
DDBI(mc), (void *) mc));
if (mc->mc_snum >= CURSOR_STACK) {
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return MDB_CURSOR_FULL;
}
mc->mc_top = mc->mc_snum++;
mc->mc_pg[mc->mc_top] = mp;
mc->mc_ki[mc->mc_top] = 0;
return MDB_SUCCESS;
}
#if MDB_RPAGE_CACHE
static int
mdb_rpage_encsum(MDB_env *env, MDB_ID3 *id3, unsigned rem, int numpgs)
{
int rc = 0;
if (env->me_encfunc) {
unsigned short muse = id3->muse;
rc = mdb_rpage_decrypt(env, id3, rem, numpgs);
if (!rc && env->me_sumfunc && muse != id3->muse) {
MDB_page *p = (MDB_page *)(id3->menc + rem * env->me_psize);
rc = mdb_page_chk_checksum(env, p, numpgs * env->me_psize);
}
} else {
if (!(id3->muse & (1 << rem))) {
MDB_page *p;
int bit;
/* If this is an overflow page, set all use bits to the end */
if (rem + numpgs > MDB_RPAGE_CHUNK)
bit = 0xffff;
else
bit = 1;
id3->muse |= (bit << rem);
p = (MDB_page *)(id3->mptr + rem * env->me_psize);
rc = mdb_page_chk_checksum(env, p, numpgs * env->me_psize);
}
}
return rc;
}
/** Map a read-only page.
* There are two levels of tracking in use, a per-txn list and a per-env list.
* ref'ing and unref'ing the per-txn list is faster since it requires no
* locking. Pages are cached in the per-env list for global reuse, and a lock
* is required. Pages are not immediately unmapped when their refcnt goes to
* zero; they hang around in case they will be reused again soon.
*
* When the per-txn list gets full, all pages with refcnt=0 are purged from the
* list and their refcnts in the per-env list are decremented.
*
* When the per-env list gets full, all pages with refcnt=0 are purged from the
* list and their pages are unmapped.
*
* @note "full" means the list has reached its respective rpcheck threshold.
* This threshold slowly raises if no pages could be purged on a given check,
* and returns to its original value when enough pages were purged.
*
* If purging doesn't free any slots, filling the per-txn list will return
* MDB_TXN_FULL, and filling the per-env list returns MDB_MAP_FULL.
*
* Reference tracking in a txn is imperfect, pages can linger with non-zero
* refcnt even without active references. It was deemed to be too invasive
* to add unrefs in every required location. However, all pages are unref'd
* at the end of the transaction. This guarantees that no stale references
* linger in the per-env list.
*
* Usually we map chunks of 16 pages at a time, but if an overflow page begins
* at the tail of the chunk we extend the chunk to include the entire overflow
* page. Unfortunately, pages can be turned into overflow pages after their
* chunk was already mapped. In that case we must remap the chunk if the
* overflow page is referenced. If the chunk's refcnt is 0 we can just remap
* it, otherwise we temporarily map a new chunk just for the overflow page.
*
* @note this chunk handling means we cannot guarantee that a data item
* returned from the DB will stay alive for the duration of the transaction:
* We unref pages as soon as a cursor moves away from the page
* A subsequent op may cause a purge, which may unmap any unref'd chunks
* The caller must copy the data if it must be used later in the same txn.
*
* Also - our reference counting revolves around cursors, but overflow pages
* aren't pointed to by a cursor's page stack. We have to remember them
* explicitly, in the added mc_ovpg field. A single cursor can only hold a
* reference to one overflow page at a time.
*
* @param[in] txn the transaction for this access.
* @param[in] pg0 the page number for the page to retrieve.
* @param[in] numpgs number of database pages (can be > 1 for overflow pages)
* @param[out] ret address of a pointer where the page's address will be stored.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_rpage_get(MDB_txn *txn, pgno_t pg0, int numpgs, MDB_page **ret)
{
MDB_env *env = txn->mt_env;
MDB_page *p;
MDB_ID3L tl = txn->mt_rpages;
MDB_ID3L el = env->me_rpages;
MDB_ID3 id3;
char *base;
unsigned x, rem;
pgno_t pgno;
int rc, retries = 1;
#ifdef _WIN32
LARGE_INTEGER off;
SIZE_T len;
#define SET_OFF(off,val) off.QuadPart = val
#define MAP(rc,env,addr,len,off) \
addr = NULL; \
rc = NtMapViewOfSection(env->me_fmh, GetCurrentProcess(), &addr, 0, \
len, &off, &len, ViewUnmap, (env->me_flags & MDB_RDONLY) ? 0 : MEM_RESERVE, PAGE_READONLY); \
if (rc) rc = mdb_nt2win32(rc)
#else
off_t off;
size_t len;
#define SET_OFF(off,val) off = val
#define MAP(rc,env,addr,len,off) \
addr = mmap(NULL, len, PROT_READ, MAP_SHARED, env->me_fd, off); \
rc = (addr == MAP_FAILED) ? errno : 0
#endif
/* remember the offset of the actual page number, so we can
* return the correct pointer at the end.
*/
rem = pg0 & (MDB_RPAGE_CHUNK-1);
pgno = pg0 ^ rem;
id3.mid = 0;
id3.menc = NULL;
id3.muse = 0;
x = mdb_mid3l_search(tl, pgno);
if (x <= tl[0].mid && tl[x].mid == pgno) {
if (x != tl[0].mid && tl[x+1].mid == pg0)
x++;
/* check for overflow size */
if (numpgs + rem > tl[x].mcnt) {
id3.mcnt = numpgs + rem;
len = id3.mcnt * env->me_psize;
SET_OFF(off, pgno * env->me_psize);
MAP(rc, env, id3.mptr, len, off);
if (rc)
return rc;
/* setup for encryption */
if (env->me_encfunc) {
id3.menc = malloc(len);
if (!id3.menc)
return ENOMEM;
}
/* check for local-only page */
if (rem) {
mdb_tassert(txn, tl[x].mid != pg0);
/* hope there's room to insert this locally.
* setting mid here tells later code to just insert
* this id3 instead of searching for a match.
*/
id3.mid = pg0;
goto notlocal;
} else {
/* ignore the mapping we got from env, use new one */
tl[x].mptr = id3.mptr;
tl[x].mcnt = id3.mcnt;
if (tl[x].menc)
mdb_rpage_dispose(env, &tl[x]);
tl[x].menc = id3.menc;
tl[x].muse = id3.muse;
/* if no active ref, see if we can replace in env */
if (!tl[x].mref) {
unsigned i;
pthread_mutex_lock(&env->me_rpmutex);
i = mdb_mid3l_search(el, tl[x].mid);
if (el[i].mref == 1) {
/* just us, replace it */
munmap(el[i].mptr, el[i].mcnt * env->me_psize);
el[i].mptr = tl[x].mptr;
el[i].mcnt = tl[x].mcnt;
if (el[i].menc)
mdb_rpage_dispose(env, &el[i]);
el[i].menc = tl[x].menc;
el[i].muse = tl[x].muse;
} else {
/* there are others, remove ourself */
el[i].mref--;
}
pthread_mutex_unlock(&env->me_rpmutex);
}
}
}
id3.mptr = tl[x].mptr;
id3.mcnt = tl[x].mcnt;
id3.menc = tl[x].menc;
id3.muse = tl[x].muse;
tl[x].mref++;
if (env->me_encfunc || env->me_sumfunc) {
rc = mdb_rpage_encsum(env, &id3, rem, numpgs);
if (rc) return rc;
tl[x].muse = id3.muse;
}
goto ok;
}
notlocal:
if (tl[0].mid >= MDB_TRPAGE_MAX - txn->mt_rpcheck) {
unsigned i, y;
/* purge unref'd pages from our list and unref in env */
pthread_mutex_lock(&env->me_rpmutex);
retry:
y = 0;
for (i=1; i<=tl[0].mid; i++) {
if (!tl[i].mref) {
if (!y) y = i;
/* tmp overflow pages don't go to env */
if (tl[i].mid & (MDB_RPAGE_CHUNK-1)) {
munmap(tl[i].mptr, tl[i].mcnt * env->me_psize);
if (tl[i].menc)
mdb_rpage_dispose(env, &tl[i]);
continue;
}
x = mdb_mid3l_search(el, tl[i].mid);
el[x].mref--;
}
}
pthread_mutex_unlock(&env->me_rpmutex);
if (!y) {
/* we didn't find any unref'd chunks.
* if we're out of room, fail.
*/
if (tl[0].mid >= MDB_TRPAGE_MAX)
return MDB_TXN_FULL;
/* otherwise, raise threshold for next time around
* and let this go.
*/
txn->mt_rpcheck /= 2;
} else {
/* we found some unused; consolidate the list */
for (i=y+1; i<= tl[0].mid; i++)
if (tl[i].mref)
tl[y++] = tl[i];
tl[0].mid = y-1;
/* decrease the check threshold toward its original value */
if (!txn->mt_rpcheck)
txn->mt_rpcheck = 1;
while (txn->mt_rpcheck < tl[0].mid && txn->mt_rpcheck < MDB_TRPAGE_SIZE/2)
txn->mt_rpcheck *= 2;
}
}
if (tl[0].mid < MDB_TRPAGE_SIZE) {
id3.mref = 1;
if (id3.mid)
goto found;
/* don't map past last written page in read-only envs */
if ((env->me_flags & MDB_RDONLY) && pgno + MDB_RPAGE_CHUNK-1 > txn->mt_last_pgno)
id3.mcnt = txn->mt_last_pgno + 1 - pgno;
else
id3.mcnt = numpgs + rem > MDB_RPAGE_CHUNK ? numpgs + rem : MDB_RPAGE_CHUNK;
len = id3.mcnt * env->me_psize;
id3.mid = pgno;
/* search for page in env */
pthread_mutex_lock(&env->me_rpmutex);
x = mdb_mid3l_search(el, pgno);
if (x <= el[0].mid && el[x].mid == pgno) {
id3.mptr = el[x].mptr;
id3.menc = el[x].menc;
id3.muse = el[x].muse;
/* check for overflow size */
if (id3.mcnt > el[x].mcnt) {
SET_OFF(off, pgno * env->me_psize);
MAP(rc, env, id3.mptr, len, off);
if (rc)
goto fail;
if (env->me_encfunc) {
id3.menc = malloc(len);
if (!id3.menc) {
rc = ENOMEM;
goto fail;
}
id3.muse = 0;
}
if (!el[x].mref) {
munmap(el[x].mptr, env->me_psize * el[x].mcnt);
el[x].mptr = id3.mptr;
el[x].mcnt = id3.mcnt;
if (el[x].menc)
mdb_rpage_dispose(env, &el[x]);
el[x].menc = id3.menc;
el[x].muse = id3.muse;
} else {
id3.mid = pg0;
if (env->me_encfunc || env->me_sumfunc) {
rc = mdb_rpage_encsum(env, &id3, rem, numpgs);
if (rc)
goto fail;
el[x].muse = id3.muse;
}
pthread_mutex_unlock(&env->me_rpmutex);
goto found;
}
}
el[x].mref++;
if (env->me_encfunc || env->me_sumfunc) {
rc = mdb_rpage_encsum(env, &id3, rem, numpgs);
if (rc)
goto fail;
el[x].muse = id3.muse;
}
pthread_mutex_unlock(&env->me_rpmutex);
goto found;
}
if (el[0].mid >= MDB_ERPAGE_MAX - env->me_rpcheck) {
/* purge unref'd pages */
unsigned i, y = 0;
for (i=1; i<=el[0].mid; i++) {
if (!el[i].mref) {
if (!y) y = i;
munmap(el[i].mptr, env->me_psize * el[i].mcnt);
if (el[i].menc)
mdb_rpage_dispose(env, &el[i]);
}
}
if (!y) {
if (retries) {
/* see if we can unref some local pages */
retries--;
id3.mid = 0;
goto retry;
}
if (el[0].mid >= MDB_ERPAGE_MAX) {
pthread_mutex_unlock(&env->me_rpmutex);
return MDB_MAP_FULL;
}
env->me_rpcheck /= 2;
} else {
for (i=y+1; i<= el[0].mid; i++)
if (el[i].mref)
el[y++] = el[i];
el[0].mid = y-1;
if (!env->me_rpcheck)
env->me_rpcheck = 1;
while (env->me_rpcheck < el[0].mid && env->me_rpcheck < MDB_ERPAGE_SIZE/2)
env->me_rpcheck *= 2;
}
}
SET_OFF(off, pgno * env->me_psize);
MAP(rc, env, id3.mptr, len, off);
if (rc) {
fail:
pthread_mutex_unlock(&env->me_rpmutex);
return rc;
}
if (env->me_encfunc) {
id3.menc = malloc(len);
if (!id3.menc) {
rc = ENOMEM;
goto fail;
}
}
if (env->me_encfunc || env->me_sumfunc) {
rc = mdb_rpage_encsum(env, &id3, rem, numpgs);
if (rc)
goto fail;
}
mdb_mid3l_insert(el, &id3);
pthread_mutex_unlock(&env->me_rpmutex);
found:
mdb_mid3l_insert(tl, &id3);
} else {
return MDB_TXN_FULL;
}
ok:
base = (char *)(env->me_encfunc ? id3.menc : id3.mptr);
p = (MDB_page *)(base + rem * env->me_psize);
rc = MDB_SUCCESS;
if (env->me_encfunc || env->me_sumfunc) {
rc = mdb_rpage_encsum(env, &id3, rem, numpgs);
}
#if MDB_DEBUG /* we don't need this check any more */
if (IS_OVERFLOW(p)) {
mdb_tassert(txn, p->mp_pages + rem <= id3.mcnt);
}
#endif
*ret = p;
return rc;
}
static int mdb_page_encrypt(MDB_env *env, MDB_page *dp, MDB_page *encp, size_t size)
{
MDB_val in, out, enckeys[3];
int xsize = sizeof(pgno_t) + sizeof(txnid_t);
in.mv_size = size - xsize;
in.mv_data = (char *)dp + xsize;
out.mv_size = in.mv_size;
out.mv_data = (char *)encp + xsize;
if (env->me_esumsize) {
in.mv_size -= env->me_esumsize;
out.mv_size -= env->me_esumsize;
enckeys[2].mv_size = env->me_esumsize;
enckeys[2].mv_data = out.mv_data + out.mv_size;
} else {
enckeys[2].mv_size = 0;
enckeys[2].mv_data = 0;
}
encp->mp_pgno = dp->mp_pgno;
encp->mp_txnid = dp->mp_txnid;
enckeys[0] = env->me_enckey;
enckeys[1].mv_size = xsize;
enckeys[1].mv_data = dp;
return env->me_encfunc(&in, &out, enckeys, 1);
}
static int mdb_rpage_decrypt(MDB_env *env, MDB_ID3 *id3, int rem, int numpgs)
{
int rc = 0;
if (!(id3->muse & (1 << rem))) {
MDB_val in, out, enckeys[3];
int bit;
int xsize = sizeof(pgno_t) + sizeof(txnid_t);
/* If this is an overflow page, set all use bits to the end */
if (rem + numpgs > MDB_RPAGE_CHUNK)
bit = 0xffff;
else
bit = 1;
id3->muse |= (bit << rem);
in.mv_size = numpgs * env->me_psize - xsize;
in.mv_data = (char *)id3->mptr + rem * env->me_psize + xsize;
enckeys[0] = env->me_enckey;
enckeys[1].mv_size = xsize;
enckeys[1].mv_data = in.mv_data - xsize;
if (env->me_esumsize) {
in.mv_size -= env->me_esumsize;
enckeys[2].mv_size = env->me_esumsize;
enckeys[2].mv_data = in.mv_data + in.mv_size;
} else {
enckeys[2].mv_size = 0;
enckeys[2].mv_data = 0;
}
out.mv_size = in.mv_size;
out.mv_data = (char *)id3->menc + rem * env->me_psize + xsize;
if (env->me_encfunc(&in, &out, enckeys, 0))
rc = MDB_CRYPTO_FAIL;
else {
MDB_page *penc, *pclr;
penc = (MDB_page *)enckeys[1].mv_data;
pclr = (MDB_page *)(out.mv_data - xsize);
pclr->mp_pgno = penc->mp_pgno;
pclr->mp_txnid = penc->mp_txnid;
}
}
return rc;
}
/** zero out decrypted pages before freeing them */
static void mdb_rpage_dispose(MDB_env *env, MDB_ID3 *id3)
{
char *base = id3->menc;
int i, j;
for (i=0, j=1; i<15; i++) {
if (id3->muse & j)
memset(base, 0, env->me_psize);
j <<= 1;
base += env->me_psize;
}
if (id3->muse & j) {
i = id3->mcnt - (MDB_RPAGE_CHUNK - 1);
memset(base, 0, i * env->me_psize);
}
free(id3->menc);
}
static void mdb_page_set_checksum(MDB_env *env, MDB_page *mp, size_t size)
{
MDB_val src, dst, *key;
src.mv_size = size - env->me_sumsize;
src.mv_data = mp;
dst.mv_size = env->me_sumsize;
dst.mv_data = src.mv_data + src.mv_size;
if (env->me_encfunc)
key = &env->me_enckey;
else
key = NULL;
env->me_sumfunc(&src, &dst, key);
}
static int mdb_page_chk_checksum(MDB_env *env, MDB_page *mp, size_t size)
{
MDB_val src, dst, chk, *key;
char sumbuf[256];
src.mv_size = size - env->me_sumsize;
src.mv_data = mp;
chk.mv_size = env->me_sumsize;
chk.mv_data = src.mv_data + src.mv_size;
dst.mv_size = env->me_sumsize;
dst.mv_data = sumbuf;
if (env->me_encfunc)
key = &env->me_enckey;
else
key = NULL;
env->me_sumfunc(&src, &dst, key);
return memcmp(chk.mv_data, dst.mv_data, env->me_sumsize) ? MDB_BAD_CHECKSUM : 0;
}
#endif
/** Find the address of the page corresponding to a given page number.
* Set #MDB_TXN_ERROR on failure.
* @param[in] mc the cursor accessing the page.
* @param[in] pgno the page number for the page to retrieve.
* @param[in] numpgs number of database pages (can be > 1 for overflow pages)
* @param[out] ret address of a pointer where the page's address will be stored.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_get(MDB_cursor *mc, pgno_t pgno,
#if MDB_RPAGE_CACHE
int numpgs,
#endif
MDB_page **ret)
{
MDB_txn *txn = mc->mc_txn, *tx2;
MDB_page *p = NULL;
if (! (mc->mc_flags & (C_ORIG_RDONLY|C_WRITEMAP))) {
for (tx2 = txn;; ) {
MDB_ID2L dl = tx2->mt_u.dirty_list;
MDB_IDL sl;
unsigned x;
/* tx2 may have malloced its own "dirty" version of the
* page, with the same page number.
*/
if (dl[0].mid) {
unsigned x = mdb_mid2l_search(dl, pgno);
if (x <= dl[0].mid && dl[x].mid == pgno) {
p = dl[x].mptr;
goto done;
}
}
/* Spilled pages were dirtied in this txn, then cleaned
* and flushed to the map when dirty_list got full.
* Check if tx2 spilled the page before moving on to
* search the parent. (But don't unspill here, leave
* that unless page_touch happens again.)
*/
sl = tx2->mt_spill_pgs;
if ((tx2 = tx2->mt_parent) == NULL)
break;
if (sl) {
MDB_ID pn = pgno << 1;
x = mdb_midl_search(sl, pn);
if (x <= sl[0] && sl[x] == pn) {
goto mapped;
}
}
}
}
if (pgno >= txn->mt_next_pgno) {
DPRINTF(("page %"Yu" not found", pgno));
txn->mt_flags |= MDB_TXN_ERROR;
return MDB_PAGE_NOTFOUND;
}
mapped:
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(txn->mt_env->me_flags)) {
int rc = mdb_rpage_get(txn, pgno, numpgs, &p);
if (rc) {
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
} else
#endif
{
MDB_env *env = txn->mt_env;
p = (MDB_page *)(env->me_map + env->me_psize * pgno);
}
done:
*ret = p;
return MDB_SUCCESS;
}
/** Finish #mdb_page_search() / #mdb_page_search_lowest().
* The cursor is at the root page, set up the rest of it.
*/
static int
mdb_page_search_root(MDB_cursor *mc, MDB_val *key, int flags)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
int rc;
DKBUF;
while (IS_BRANCH(mp)) {
MDB_node *node;
indx_t i;
DPRINTF(("branch page %"Yu" has %u keys", mp->mp_pgno, NUMKEYS(mp)));
/* Don't assert on branch pages in the FreeDB. We can get here
* while in the process of rebalancing a FreeDB branch page; we must
* let that proceed. ITS#8336
*/
mdb_cassert(mc, !mc->mc_dbi || NUMKEYS(mp) > 1);
DPRINTF(("found index 0 to page %"Yu, NODEPGNO(NODEPTR(mp, 0))));
if (flags & (MDB_PS_FIRST|MDB_PS_LAST)) {
i = 0;
if (flags & MDB_PS_LAST) {
i = NUMKEYS(mp) - 1;
/* if already init'd, see if we're already in right place */
if (mc->mc_flags & C_INITIALIZED) {
if (mc->mc_ki[mc->mc_top] == i) {
mc->mc_top = mc->mc_snum++;
mp = mc->mc_pg[mc->mc_top];
goto ready;
}
}
}
} else {
int exact;
node = mdb_node_search(mc, key, &exact);
if (node == NULL)
i = NUMKEYS(mp) - 1;
else {
i = mc->mc_ki[mc->mc_top];
if (!exact) {
mdb_cassert(mc, i > 0);
i--;
}
}
DPRINTF(("following index %u for key [%s]", i, DKEY(key)));
}
mdb_cassert(mc, i < NUMKEYS(mp));
node = NODEPTR(mp, i);
if ((rc = MDB_PAGE_GET(mc, NODEPGNO(node), 1, &mp)) != 0)
return rc;
mc->mc_ki[mc->mc_top] = i;
if ((rc = mdb_cursor_push(mc, mp)))
return rc;
ready:
if (flags & MDB_PS_MODIFY) {
if ((rc = mdb_page_touch(mc)) != 0)
return rc;
mp = mc->mc_pg[mc->mc_top];
}
}
if (!IS_LEAF(mp)) {
DPRINTF(("internal error, index points to a %02X page!?",
mp->mp_flags));
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return MDB_CORRUPTED;
}
DPRINTF(("found leaf page %"Yu" for key [%s]", mp->mp_pgno,
key ? DKEY(key) : "null"));
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
return MDB_SUCCESS;
}
/** Search for the lowest key under the current branch page.
* This just bypasses a NUMKEYS check in the current page
* before calling mdb_page_search_root(), because the callers
* are all in situations where the current page is known to
* be underfilled.
*/
static int
mdb_page_search_lowest(MDB_cursor *mc)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_node *node = NODEPTR(mp, 0);
int rc;
if ((rc = MDB_PAGE_GET(mc, NODEPGNO(node), 1, &mp)) != 0)
return rc;
mc->mc_ki[mc->mc_top] = 0;
if ((rc = mdb_cursor_push(mc, mp)))
return rc;
return mdb_page_search_root(mc, NULL, MDB_PS_FIRST);
}
/** Search for the page a given key should be in.
* Push it and its parent pages on the cursor stack.
* @param[in,out] mc the cursor for this operation.
* @param[in] key the key to search for, or NULL for first/last page.
* @param[in] flags If MDB_PS_MODIFY is set, visited pages in the DB
* are touched (updated with new page numbers).
* If MDB_PS_FIRST or MDB_PS_LAST is set, find first or last leaf.
* This is used by #mdb_cursor_first() and #mdb_cursor_last().
* If MDB_PS_ROOTONLY set, just fetch root node, no further lookups.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
{
int rc;
pgno_t root;
/* Make sure the txn is still viable, then find the root from
* the txn's db table and set it as the root of the cursor's stack.
*/
if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED) {
DPUTS("transaction may not be used now");
return MDB_BAD_TXN;
} else {
/* Make sure we're using an up-to-date root */
if (*mc->mc_dbflag & DB_STALE) {
MDB_cursor mc2;
if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
return MDB_BAD_DBI;
mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 0);
if (rc)
return rc;
{
MDB_val data;
int exact = 0;
uint16_t flags;
MDB_node *leaf = mdb_node_search(&mc2,
&mc->mc_dbx->md_name, &exact);
if (!exact)
return MDB_NOTFOUND;
if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
return MDB_INCOMPATIBLE; /* not a named DB */
rc = mdb_node_read(&mc2, leaf, &data);
if (rc)
return rc;
memcpy(&flags, ((char *) data.mv_data + offsetof(MDB_db, md_flags)),
sizeof(uint16_t));
/* The txn may not know this DBI, or another process may
* have dropped and recreated the DB with other flags.
*/
if ((mc->mc_db->md_flags & PERSISTENT_FLAGS) != flags)
return MDB_INCOMPATIBLE;
memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db));
}
*mc->mc_dbflag &= ~DB_STALE;
}
root = mc->mc_db->md_root;
if (root == P_INVALID) { /* Tree is empty. */
DPUTS("tree is empty");
return MDB_NOTFOUND;
}
}
mdb_cassert(mc, root > 1);
if (!mc->mc_pg[0] || mc->mc_pg[0]->mp_pgno != root) {
#if MDB_RPAGE_CACHE
if (mc->mc_pg[0])
MDB_PAGE_UNREF(mc->mc_txn, mc->mc_pg[0]);
#endif
if ((rc = MDB_PAGE_GET(mc, root, 1, &mc->mc_pg[0])) != 0)
return rc;
}
#if MDB_RPAGE_CACHE
if (MDB_REMAPPING(mc->mc_txn->mt_env->me_flags))
{
int i;
for (i=1; i<mc->mc_snum; i++)
mdb_page_unref(mc->mc_txn, mc->mc_pg[i]);
}
#endif
mc->mc_snum = 1;
mc->mc_top = 0;
DPRINTF(("db %d root page %"Yu" has flags 0x%X",
DDBI(mc), root, mc->mc_pg[0]->mp_flags));
if (flags & MDB_PS_MODIFY) {
if ((rc = mdb_page_touch(mc)))
return rc;
}
if (flags & MDB_PS_ROOTONLY)
return MDB_SUCCESS;
return mdb_page_search_root(mc, key, flags);
}
static int
mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
{
MDB_txn *txn = mc->mc_txn;
pgno_t pg = mp->mp_pgno;
unsigned x = 0, ovpages = mp->mp_pages;
MDB_env *env = txn->mt_env;
MDB_ID pn = pg << 1;
MDB_page *freeme = NULL;
int rc;
DPRINTF(("free ov page %"Yu" (%d)", pg, ovpages));
/* If the page is dirty or on the spill list we just acquired it,
* so we should give it back to our current free list, if any.
* Otherwise put it onto the list of pages we freed in this txn.
*
* Won't create me_pghead: me_pglast must be inited along with it.
* Unsupported in nested txns: They would need to hide the page
* range in ancestor txns' dirty and spilled lists.
*/
if (IS_MUTABLE(txn, mp) && env->me_pghead && !txn->mt_parent) {
unsigned i, j;
pgno_t *mop;
MDB_ID2 *dl, ix, iy;
rc = mdb_midl_need(&env->me_pghead, ovpages);
if (rc)
return rc;
if (!IS_DIRTY_NW(txn, mp)) { /* spilled or WRITEMAP */
MDB_IDL sl = txn->mt_spill_pgs;
if (sl) {
x = mdb_midl_search(sl, pn);
if (! (x <= sl[0] && sl[x] == pn))
return MDB_PROBLEM;
/* This page is no longer spilled */
if (x == sl[0])
sl[0]--;
else
sl[x] |= 1;
}
goto release;
}
/* Remove from dirty list */
dl = txn->mt_u.dirty_list;
x = dl[0].mid--;
for (ix = dl[x]; ix.mptr != mp; ix = iy) {
if (x > 1) {
x--;
iy = dl[x];
dl[x] = ix;
} else {
mdb_cassert(mc, x > 1);
j = ++(dl[0].mid);
dl[j] = ix; /* Unsorted. OK when MDB_TXN_ERROR. */
txn->mt_flags |= MDB_TXN_ERROR;
return MDB_PROBLEM;
}
}
txn->mt_dirty_room++;
freeme = mp;
release:
/* Insert in me_pghead */
mop = env->me_pghead;
j = mop[0] + ovpages;
for (i = mop[0]; i && mop[i] < pg; i--)
mop[j--] = mop[i];
while (j>i)
mop[j--] = pg++;
mop[0] += ovpages;
} else {
rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);
if (rc)
return rc;
}
if (MC_OVPG(mc) == mp)
MC_SET_OVPG(mc, NULL);
mc->mc_db->md_overflow_pages -= ovpages;
if (MDB_REMAPPING(env->me_flags))
mdb_ovpage_unref_all(mc, mp);
if (freeme)
mdb_dpage_free(env, freeme);
return 0;
}
/** Return the data associated with a given node.
* @param[in] mc The cursor for this operation.
* @param[in] leaf The node being read.
* @param[out] data Updated to point to the node's data.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_node_read(MDB_cursor *mc, MDB_node *leaf, MDB_val *data)
{
MDB_page *omp; /* overflow page */
MDB_ovpage ovp;
int rc;
if (MC_OVPG(mc)) {
MDB_PAGE_UNREF(mc->mc_txn, MC_OVPG(mc));
MC_SET_OVPG(mc, NULL);
}
data->mv_size = NODEDSZ(leaf);
if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
data->mv_data = NODEDATA(leaf);
return MDB_SUCCESS;
}
/* Read overflow data.
*/
memcpy(&ovp, NODEDATA(leaf), sizeof(ovp));
{
if ((rc = MDB_PAGE_GET(mc, ovp.op_pgno, ovp.op_pages, &omp)) != 0) {
DPRINTF(("read overflow page %"Yu" failed", ovp.op_pgno));
return rc;
}
}
data->mv_data = METADATA(omp);
MC_SET_OVPG(mc, omp);
return MDB_SUCCESS;
}
int
mdb_get(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data)
{
MDB_cursor mc;
MDB_xcursor mx;
int exact = 0, rc;
DKBUF;
DPRINTF(("===> get db %u key [%s]", dbi, DKEY(key)));
if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
if (txn->mt_flags & MDB_TXN_BLOCKED)
return MDB_BAD_TXN;
mdb_cursor_init(&mc, txn, dbi, &mx);
rc = mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
/* unref all the pages when MDB_REMAP_CHUNKS - caller must copy the data
* before doing anything else
*/
MDB_CURSOR_UNREF(&mc, 1);
return rc;
}
/** Find a sibling for a page.
* Replaces the page at the top of the cursor's stack with the
* specified sibling, if one exists.
* @param[in] mc The cursor for this operation.
* @param[in] move_right Non-zero if the right sibling is requested,
* otherwise the left sibling.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_cursor_sibling(MDB_cursor *mc, int move_right)
{
int rc;
MDB_node *indx;
MDB_page *mp;
#if MDB_RPAGE_CACHE
MDB_page *op;
#endif
if (mc->mc_snum < 2) {
return MDB_NOTFOUND; /* root has no siblings */
}
#if MDB_RPAGE_CACHE
op = mc->mc_pg[mc->mc_top];
#endif
mdb_cursor_pop(mc);
DPRINTF(("parent page is page %"Yu", index %u",
mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]));
if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
: (mc->mc_ki[mc->mc_top] == 0)) {
DPRINTF(("no more keys left, moving to %s sibling",
move_right ? "right" : "left"));
if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {
/* undo cursor_pop before returning */
mc->mc_top++;
mc->mc_snum++;
return rc;
}
} else {
if (move_right)
mc->mc_ki[mc->mc_top]++;
else
mc->mc_ki[mc->mc_top]--;
DPRINTF(("just moving to %s index key %u",
move_right ? "right" : "left", mc->mc_ki[mc->mc_top]));
}
mdb_cassert(mc, IS_BRANCH(mc->mc_pg[mc->mc_top]));
MDB_PAGE_UNREF(mc->mc_txn, op);
indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if ((rc = MDB_PAGE_GET(mc, NODEPGNO(indx), 1, &mp)) != 0) {
/* mc will be inconsistent if caller does mc_snum++ as above */
mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
return rc;
}
mdb_cursor_push(mc, mp);
if (!move_right)
mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
return MDB_SUCCESS;
}
/** Move the cursor to the next data item. */
static int
mdb_cursor_next(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
{
MDB_page *mp;
MDB_node *leaf;
int rc;
if ((mc->mc_flags & C_DEL && op == MDB_NEXT_DUP))
return MDB_NOTFOUND;
if (!(mc->mc_flags & C_INITIALIZED))
return mdb_cursor_first(mc, key, data);
mp = mc->mc_pg[mc->mc_top];
if (mc->mc_flags & C_EOF) {
if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mp)-1)
return MDB_NOTFOUND;
mc->mc_flags ^= C_EOF;
}
if (mc->mc_db->md_flags & MDB_DUPSORT) {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
if (op != MDB_NEXT || rc != MDB_NOTFOUND) {
if (rc == MDB_SUCCESS)
MDB_GET_KEY(leaf, key);
return rc;
}
}
else {
MDB_CURSOR_UNREF(&mc->mc_xcursor->mx_cursor, 0);
}
} else {
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if (op == MDB_NEXT_DUP)
return MDB_NOTFOUND;
}
}
DPRINTF(("cursor_next: top page is %"Yu" in cursor %p",
mdb_dbg_pgno(mp), (void *) mc));
if (mc->mc_flags & C_DEL) {
mc->mc_flags ^= C_DEL;
goto skip;
}
if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
DPUTS("=====> move to next sibling page");
if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
mc->mc_flags |= C_EOF;
return rc;
}
mp = mc->mc_pg[mc->mc_top];
DPRINTF(("next page is %"Yu", key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
} else
mc->mc_ki[mc->mc_top]++;
skip:
DPRINTF(("==> cursor points to page %"Yu" with %u keys, key index %u",
mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
mdb_cassert(mc, IS_LEAF(mp));
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
return rc;
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
/** Move the cursor to the previous data item. */
static int
mdb_cursor_prev(MDB_cursor *mc, MDB_val *key, MDB_val *data, MDB_cursor_op op)
{
MDB_page *mp;
MDB_node *leaf;
int rc;
if (!(mc->mc_flags & C_INITIALIZED)) {
rc = mdb_cursor_last(mc, key, data);
if (rc)
return rc;
mc->mc_ki[mc->mc_top]++;
}
mp = mc->mc_pg[mc->mc_top];
if (mc->mc_db->md_flags & MDB_DUPSORT) {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_PREV || op == MDB_PREV_DUP) {
rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
if (op != MDB_PREV || rc != MDB_NOTFOUND) {
if (rc == MDB_SUCCESS) {
MDB_GET_KEY(leaf, key);
mc->mc_flags &= ~C_EOF;
}
return rc;
}
}
else {
MDB_CURSOR_UNREF(&mc->mc_xcursor->mx_cursor, 0);
}
} else {
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if (op == MDB_PREV_DUP)
return MDB_NOTFOUND;
}
}
DPRINTF(("cursor_prev: top page is %"Yu" in cursor %p",
mdb_dbg_pgno(mp), (void *) mc));
mc->mc_flags &= ~(C_EOF|C_DEL);
if (mc->mc_ki[mc->mc_top] == 0) {
DPUTS("=====> move to prev sibling page");
if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {
return rc;
}
mp = mc->mc_pg[mc->mc_top];
mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
DPRINTF(("prev page is %"Yu", key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
} else
mc->mc_ki[mc->mc_top]--;
DPRINTF(("==> cursor points to page %"Yu" with %u keys, key index %u",
mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
mdb_cassert(mc, IS_LEAF(mp));
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
return rc;
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
/** Set the cursor on a specific data item. */
static int
mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
MDB_cursor_op op, int *exactp)
{
int rc;
MDB_page *mp;
MDB_node *leaf = NULL;
DKBUF;
if (key->mv_size == 0)
return MDB_BAD_VALSIZE;
if (mc->mc_xcursor) {
MDB_CURSOR_UNREF(&mc->mc_xcursor->mx_cursor, 0);
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
}
/* See if we're already on the right page */
if (mc->mc_flags & C_INITIALIZED) {
MDB_val nodekey;
mp = mc->mc_pg[mc->mc_top];
if (!NUMKEYS(mp)) {
mc->mc_ki[mc->mc_top] = 0;
return MDB_NOTFOUND;
}
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_size = mc->mc_db->md_pad;
nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
} else {
leaf = NODEPTR(mp, 0);
MDB_GET_KEY2(leaf, nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
/* Probably happens rarely, but first node on the page
* was the one we wanted.
*/
mc->mc_ki[mc->mc_top] = 0;
if (exactp)
*exactp = 1;
goto set1;
}
if (rc > 0) {
unsigned int i;
unsigned int nkeys = NUMKEYS(mp);
if (nkeys > 1) {
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
nkeys-1, nodekey.mv_size);
} else {
leaf = NODEPTR(mp, nkeys-1);
MDB_GET_KEY2(leaf, nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
/* last node was the one we wanted */
mc->mc_ki[mc->mc_top] = nkeys-1;
if (exactp)
*exactp = 1;
goto set1;
}
if (rc < 0) {
if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
/* This is definitely the right page, skip search_page */
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
mc->mc_ki[mc->mc_top], nodekey.mv_size);
} else {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
MDB_GET_KEY2(leaf, nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
/* current node was the one we wanted */
if (exactp)
*exactp = 1;
goto set1;
}
}
rc = 0;
mc->mc_flags &= ~C_EOF;
goto set2;
}
}
/* If any parents have right-sibs, search.
* Otherwise, there's nothing further.
*/
for (i=0; i<mc->mc_top; i++)
if (mc->mc_ki[i] <
NUMKEYS(mc->mc_pg[i])-1)
break;
if (i == mc->mc_top) {
/* There are no other pages */
mc->mc_ki[mc->mc_top] = nkeys;
return MDB_NOTFOUND;
}
}
if (!mc->mc_top) {
/* There are no other pages */
mc->mc_ki[mc->mc_top] = 0;
if (op == MDB_SET_RANGE && !exactp) {
rc = 0;
goto set1;
} else
return MDB_NOTFOUND;
}
} else {
mc->mc_pg[0] = 0;
}
rc = mdb_page_search(mc, key, 0);
if (rc != MDB_SUCCESS)
return rc;
mp = mc->mc_pg[mc->mc_top];
mdb_cassert(mc, IS_LEAF(mp));
set2:
leaf = mdb_node_search(mc, key, exactp);
if (exactp != NULL && !*exactp) {
/* MDB_SET specified and not an exact match. */
return MDB_NOTFOUND;
}
if (leaf == NULL) {
DPUTS("===> inexact leaf not found, goto sibling");
if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
mc->mc_flags |= C_EOF;
return rc; /* no entries matched */
}
mp = mc->mc_pg[mc->mc_top];
mdb_cassert(mc, IS_LEAF(mp));
leaf = NODEPTR(mp, 0);
}
set1:
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
if (IS_LEAF2(mp)) {
if (op == MDB_SET_RANGE || op == MDB_SET_KEY) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
}
return MDB_SUCCESS;
}
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
} else {
int ex2, *ex2p;
if (op == MDB_GET_BOTH) {
ex2p = &ex2;
ex2 = 0;
} else {
ex2p = NULL;
}
rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
if (rc != MDB_SUCCESS)
return rc;
}
} else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
MDB_val olddata;
MDB_cmp_func *dcmp;
if ((rc = mdb_node_read(mc, leaf, &olddata)) != MDB_SUCCESS)
return rc;
dcmp = mc->mc_dbx->md_dcmp;
if (NEED_CMP_CLONG(dcmp, olddata.mv_size))
dcmp = mdb_cmp_clong;
rc = dcmp(data, &olddata);
if (rc) {
if (op == MDB_GET_BOTH || rc > 0)
return MDB_NOTFOUND;
rc = 0;
}
*data = olddata;
} else {
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
/* The key already matches in all other cases */
if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
MDB_GET_KEY(leaf, key);
DPRINTF(("==> cursor placed on key [%s]", DKEY(key)));
return rc;
}
/** Move the cursor to the first item in the database. */
static int
mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
{
int rc;
MDB_node *leaf;
if (mc->mc_xcursor) {
MDB_CURSOR_UNREF(&mc->mc_xcursor->mx_cursor, 0);
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
}
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
if (rc != MDB_SUCCESS)
return rc;
}
mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
mc->mc_ki[mc->mc_top] = 0;
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
return MDB_SUCCESS;
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
} else {
if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
/** Move the cursor to the last item in the database. */
static int
mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
{
int rc;
MDB_node *leaf;
if (mc->mc_xcursor) {
MDB_CURSOR_UNREF(&mc->mc_xcursor->mx_cursor, 0);
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
}
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
rc = mdb_page_search(mc, NULL, MDB_PS_LAST);
if (rc != MDB_SUCCESS)
return rc;
}
mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
mc->mc_flags |= C_INITIALIZED|C_EOF;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
} else {
if ((rc = mdb_node_read(mc, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
}
int
mdb_cursor_get(MDB_cursor *mc, MDB_val *key, MDB_val *data,
MDB_cursor_op op)
{
int rc;
int exact = 0;
int (*mfunc)(MDB_cursor *mc, MDB_val *key, MDB_val *data);
if (mc == NULL)
return EINVAL;
if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)
return MDB_BAD_TXN;
switch (op) {
case MDB_GET_CURRENT:
if (!(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
} else {
MDB_page *mp = mc->mc_pg[mc->mc_top];
int nkeys = NUMKEYS(mp);
if (!nkeys || mc->mc_ki[mc->mc_top] >= nkeys) {
mc->mc_ki[mc->mc_top] = nkeys;
rc = MDB_NOTFOUND;
break;
}
rc = MDB_SUCCESS;
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
} else {
MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
MDB_GET_KEY(leaf, key);
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
} else {
rc = mdb_node_read(mc, leaf, data);
}
}
}
}
break;
case MDB_GET_BOTH:
case MDB_GET_BOTH_RANGE:
if (data == NULL) {
rc = EINVAL;
break;
}
if (mc->mc_xcursor == NULL) {
rc = MDB_INCOMPATIBLE;
break;
}
/* FALLTHRU */
case MDB_SET:
case MDB_SET_KEY:
case MDB_SET_RANGE:
if (key == NULL) {
rc = EINVAL;
} else {
rc = mdb_cursor_set(mc, key, data, op,
op == MDB_SET_RANGE ? NULL : &exact);
}
break;
case MDB_GET_MULTIPLE:
if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
rc = MDB_INCOMPATIBLE;
break;
}
rc = MDB_SUCCESS;
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
(mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
break;
goto fetchm;
case MDB_NEXT_MULTIPLE:
if (data == NULL) {
rc = EINVAL;
break;
}
if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
rc = MDB_INCOMPATIBLE;
break;
}
rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
if (rc == MDB_SUCCESS) {
if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
MDB_cursor *mx;
fetchm:
mx = &mc->mc_xcursor->mx_cursor;
data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
mx->mc_db->md_pad;
data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
} else {
rc = MDB_NOTFOUND;
}
}
break;
case MDB_PREV_MULTIPLE:
if (data == NULL) {
rc = EINVAL;
break;
}
if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
rc = MDB_INCOMPATIBLE;
break;
}
if (!(mc->mc_flags & C_INITIALIZED))
rc = mdb_cursor_last(mc, key, data);
else
rc = MDB_SUCCESS;
if (rc == MDB_SUCCESS) {
MDB_cursor *mx = &mc->mc_xcursor->mx_cursor;
if (mx->mc_flags & C_INITIALIZED) {
rc = mdb_cursor_sibling(mx, 0);
if (rc == MDB_SUCCESS)
goto fetchm;
} else {
rc = MDB_NOTFOUND;
}
}
break;
case MDB_NEXT:
case MDB_NEXT_DUP:
case MDB_NEXT_NODUP:
rc = mdb_cursor_next(mc, key, data, op);
break;
case MDB_PREV:
case MDB_PREV_DUP:
case MDB_PREV_NODUP:
rc = mdb_cursor_prev(mc, key, data, op);
break;
case MDB_FIRST:
rc = mdb_cursor_first(mc, key, data);
break;
case MDB_FIRST_DUP:
mfunc = mdb_cursor_first;
mmove:
if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
if (mc->mc_xcursor == NULL) {
rc = MDB_INCOMPATIBLE;
break;
}
if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top])) {
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
rc = MDB_NOTFOUND;
break;
}
{
MDB_node *leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
MDB_GET_KEY(leaf, key);
rc = mdb_node_read(mc, leaf, data);
break;
}
}
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
rc = mfunc(&mc->mc_xcursor->mx_cursor, data, NULL);
break;
case MDB_LAST:
rc = mdb_cursor_last(mc, key, data);
break;
case MDB_LAST_DUP:
mfunc = mdb_cursor_last;
goto mmove;
default:
DPRINTF(("unhandled/unimplemented cursor operation %u", op));
rc = EINVAL;
break;
}
if (mc->mc_flags & C_DEL)
mc->mc_flags ^= C_DEL;
return rc;
}
/** Touch all the pages in the cursor stack. Set mc_top.
* Makes sure all the pages are writable, before attempting a write operation.
* @param[in] mc The cursor to operate on.
*/
static int
mdb_cursor_touch(MDB_cursor *mc)
{
int rc = MDB_SUCCESS;
if (mc->mc_dbi >= CORE_DBS && !(*mc->mc_dbflag & (DB_DIRTY|DB_DUPDATA))) {
/* Touch DB record of named DB */
MDB_cursor mc2;
MDB_xcursor mcx;
if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
return MDB_BAD_DBI;
mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, &mcx);
rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
if (rc)
return rc;
*mc->mc_dbflag |= DB_DIRTY;
}
mc->mc_top = 0;
if (mc->mc_snum) {
do {
rc = mdb_page_touch(mc);
} while (!rc && ++(mc->mc_top) < mc->mc_snum);
mc->mc_top = mc->mc_snum-1;
}
return rc;
}
/** Do not spill pages to disk if txn is getting full, may fail instead */
#define MDB_NOSPILL 0x8000
int
mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
unsigned int flags)
{
MDB_env *env;
MDB_node *leaf = NULL;
MDB_page *fp, *mp, *sub_root = NULL;
uint16_t fp_flags;
MDB_val xdata, *rdata, dkey, olddata;
MDB_db dummy;
int do_sub = 0, insert_key, insert_data;
unsigned int mcount = 0, dcount = 0, nospill;
size_t nsize;
int rc, rc2;
unsigned int nflags;
DKBUF;
if (mc == NULL || key == NULL)
return EINVAL;
env = mc->mc_txn->mt_env;
/* Check this first so counter will always be zero on any
* early failures.
*/
if (flags & MDB_MULTIPLE) {
dcount = data[1].mv_size;
data[1].mv_size = 0;
if (!F_ISSET(mc->mc_db->md_flags, MDB_DUPFIXED))
return MDB_INCOMPATIBLE;
}
nospill = flags & MDB_NOSPILL;
flags &= ~MDB_NOSPILL;
if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
if (key->mv_size-1 >= ENV_MAXKEY(env))
return MDB_BAD_VALSIZE;
#if SIZE_MAX > MAXDATASIZE
if (data->mv_size > ((mc->mc_db->md_flags & MDB_DUPSORT) ? ENV_MAXKEY(env) : MAXDATASIZE))
return MDB_BAD_VALSIZE;
#else
if ((mc->mc_db->md_flags & MDB_DUPSORT) && data->mv_size > ENV_MAXKEY(env))
return MDB_BAD_VALSIZE;
#endif
DPRINTF(("==> put db %d key [%s], size %"Z"u, data size %"Z"u",
DDBI(mc), DKEY(key), key ? key->mv_size : 0, data->mv_size));
dkey.mv_size = 0;
if (flags & MDB_CURRENT) {
if (!(mc->mc_flags & C_INITIALIZED))
return EINVAL;
rc = MDB_SUCCESS;
} else if (mc->mc_db->md_root == P_INVALID) {
/* new database, cursor has nothing to point to */
mc->mc_snum = 0;
mc->mc_top = 0;
mc->mc_flags &= ~C_INITIALIZED;
rc = MDB_NO_ROOT;
} else {
int exact = 0;
MDB_val d2;
if (flags & MDB_APPEND) {
MDB_val k2;
rc = mdb_cursor_last(mc, &k2, &d2);
if (rc == 0) {
rc = mc->mc_dbx->md_cmp(key, &k2);
if (rc > 0) {
rc = MDB_NOTFOUND;
mc->mc_ki[mc->mc_top]++;
} else {
/* new key is <= last key */
rc = MDB_KEYEXIST;
}
}
} else {
rc = mdb_cursor_set(mc, key, &d2, MDB_SET, &exact);
}
if ((flags & MDB_NOOVERWRITE) && rc == 0) {
DPRINTF(("duplicate key [%s]", DKEY(key)));
*data = d2;
return MDB_KEYEXIST;
}
if (rc && rc != MDB_NOTFOUND)
return rc;
}
if (mc->mc_flags & C_DEL)
mc->mc_flags ^= C_DEL;
/* Cursor is positioned, check for room in the dirty list */
if (!nospill) {
if (flags & MDB_MULTIPLE) {
rdata = &xdata;
xdata.mv_size = data->mv_size * dcount;
} else {
rdata = data;
}
if ((rc2 = mdb_page_spill(mc, key, rdata)))
return rc2;
}
if (rc == MDB_NO_ROOT) {
MDB_page *np;
/* new database, write a root leaf page */
DPUTS("allocating new root leaf page");
if ((rc2 = mdb_page_new(mc, P_LEAF, 1, &np))) {
return rc2;
}
mdb_cursor_push(mc, np);
mc->mc_db->md_root = np->mp_pgno;
mc->mc_db->md_depth++;
*mc->mc_dbflag |= DB_DIRTY;
if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
== MDB_DUPFIXED)
np->mp_flags |= P_LEAF2;
mc->mc_flags |= C_INITIALIZED;
} else {
/* make sure all cursor pages are writable */
rc2 = mdb_cursor_touch(mc);
if (rc2)
return rc2;
}
insert_key = insert_data = rc;
if (insert_key) {
/* The key does not exist */
DPRINTF(("inserting key at index %i", mc->mc_ki[mc->mc_top]));
if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
LEAFSIZE(key, data) > env->me_nodemax)
{
/* Too big for a node, insert in sub-DB. Set up an empty
* "old sub-page" for prep_subDB to expand to a full page.
*/
fp_flags = P_LEAF;
fp = env->me_pbuf;
fp->mp_pad = data->mv_size; /* used if MDB_DUPFIXED */
fp->mp_lower = fp->mp_upper = (PAGEHDRSZ-PAGEBASE);
olddata.mv_size = PAGEHDRSZ;
goto prep_subDB;
}
} else {
/* there's only a key anyway, so this is a no-op */
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
char *ptr;
unsigned int ksize = mc->mc_db->md_pad;
if (key->mv_size != ksize)
return MDB_BAD_VALSIZE;
ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
memcpy(ptr, key->mv_data, ksize);
fix_parent:
/* if overwriting slot 0 of leaf, need to
* update branch key if there is a parent page
*/
if (mc->mc_top && !mc->mc_ki[mc->mc_top]) {
unsigned short dtop = 1;
mc->mc_top--;
/* slot 0 is always an empty key, find real slot */
while (mc->mc_top && !mc->mc_ki[mc->mc_top]) {
mc->mc_top--;
dtop++;
}
if (mc->mc_ki[mc->mc_top])
rc2 = mdb_update_key(mc, key);
else
rc2 = MDB_SUCCESS;
mc->mc_top += dtop;
if (rc2)
return rc2;
}
return MDB_SUCCESS;
}
more:
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
olddata.mv_size = NODEDSZ(leaf);
olddata.mv_data = NODEDATA(leaf);
/* DB has dups? */
if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
/* Prepare (sub-)page/sub-DB to accept the new item,
* if needed. fp: old sub-page or a header faking
* it. mp: new (sub-)page. offset: growth in page
* size. xdata: node data with new page or DB.
*/
unsigned i, offset = 0;
mp = fp = xdata.mv_data = env->me_pbuf;
mp->mp_pgno = mc->mc_pg[mc->mc_top]->mp_pgno;
mp->mp_txnid = mc->mc_txn->mt_txnid;
/* Was a single item before, must convert now */
if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
MDB_cmp_func *dcmp;
/* Just overwrite the current item */
if (flags == MDB_CURRENT)
goto current;
dcmp = mc->mc_dbx->md_dcmp;
if (NEED_CMP_CLONG(dcmp, olddata.mv_size))
dcmp = mdb_cmp_clong;
/* does data match? */
if (!dcmp(data, &olddata)) {
if (flags & (MDB_NODUPDATA|MDB_APPENDDUP))
return MDB_KEYEXIST;
/* overwrite it */
goto current;
}
/* Back up original data item */
dkey.mv_size = olddata.mv_size;
dkey.mv_data = memcpy(fp+1, olddata.mv_data, olddata.mv_size);
/* Make sub-page header for the dup items, with dummy body */
fp->mp_flags = P_LEAF|P_SUBP;
fp->mp_lower = (PAGEHDRSZ-PAGEBASE);
xdata.mv_size = PAGEHDRSZ + dkey.mv_size + data->mv_size;
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
fp->mp_flags |= P_LEAF2;
fp->mp_pad = data->mv_size;
xdata.mv_size += 2 * data->mv_size; /* leave space for 2 more */
} else {
xdata.mv_size += 2 * (sizeof(indx_t) + NODESIZE) +
(dkey.mv_size & 1) + (data->mv_size & 1);
}
fp->mp_upper = xdata.mv_size - PAGEBASE;
olddata.mv_size = xdata.mv_size; /* pretend olddata is fp */
} else if (leaf->mn_flags & F_SUBDATA) {
/* Data is on sub-DB, just store it */
flags |= F_DUPDATA|F_SUBDATA;
goto put_sub;
} else {
/* Data is on sub-page */
fp = olddata.mv_data;
switch (flags) {
default:
if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
offset = EVEN(NODESIZE + sizeof(indx_t) +
data->mv_size);
break;
}
offset = fp->mp_pad;
if (SIZELEFT(fp) < offset) {
offset *= 4; /* space for 4 more */
break;
}
/* FALLTHRU */ /* Big enough MDB_DUPFIXED sub-page */
case MDB_CURRENT:
COPY_PGNO(fp->mp_pgno, mp->mp_pgno);
mc->mc_xcursor->mx_cursor.mc_pg[0] = fp;
flags |= F_DUPDATA;
goto put_sub;
}
xdata.mv_size = olddata.mv_size + offset;
}
fp_flags = fp->mp_flags;
if (NODESIZE + NODEKSZ(leaf) + xdata.mv_size > env->me_nodemax) {
/* Too big for a sub-page, convert to sub-DB */
fp_flags &= ~P_SUBP;
prep_subDB:
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
fp_flags |= P_LEAF2;
dummy.md_pad = fp->mp_pad;
dummy.md_flags = MDB_DUPFIXED;
if (mc->mc_db->md_flags & MDB_INTEGERDUP)
dummy.md_flags |= MDB_INTEGERKEY;
} else {
dummy.md_pad = 0;
dummy.md_flags = 0;
}
dummy.md_depth = 1;
dummy.md_branch_pages = 0;
dummy.md_leaf_pages = 1;
dummy.md_overflow_pages = 0;
dummy.md_entries = NUMKEYS(fp);
xdata.mv_size = sizeof(MDB_db);
xdata.mv_data = &dummy;
if ((rc = mdb_page_alloc(mc, 1, &mp)))
return rc;
fp_flags |= mp->mp_flags; /* P_ADM_FLAGS */
offset = env->me_psize - olddata.mv_size;
flags |= F_DUPDATA|F_SUBDATA;
dummy.md_root = mp->mp_pgno;
sub_root = mp;
}
if (mp != fp) {
mp->mp_flags = fp_flags;
mp->mp_pad = fp->mp_pad;
mp->mp_lower = fp->mp_lower;
mp->mp_upper = fp->mp_upper + offset;
if (fp_flags & P_LEAF2) {
memcpy(METADATA(mp), METADATA(fp), NUMKEYS(fp) * fp->mp_pad);
} else {
memcpy((char *)mp + mp->mp_upper + PAGEBASE, (char *)fp + fp->mp_upper + PAGEBASE,
olddata.mv_size - fp->mp_upper - PAGEBASE);
memcpy((char *)(&mp->mp_ptrs), (char *)(&fp->mp_ptrs), NUMKEYS(fp) * sizeof(mp->mp_ptrs[0]));
for (i=0; i<NUMKEYS(fp); i++)
mp->mp_ptrs[i] += offset;
}
}
rdata = &xdata;
flags |= F_DUPDATA;
do_sub = 1;
if (!insert_key)
mdb_node_del(mc, 0);
goto new_sub;
}
current:
/* LMDB passes F_SUBDATA in 'flags' to write a DB record */
if ((leaf->mn_flags ^ flags) & F_SUBDATA)
return MDB_INCOMPATIBLE;
/* overflow page overwrites need special handling */
if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
MDB_page *omp;
MDB_ovpage ovp;
int ovpages, dpages = OVPAGES(data->mv_size, env->me_psize);
memcpy(&ovp, olddata.mv_data, sizeof(ovp));
if ((rc2 = MDB_PAGE_GET(mc, ovp.op_pgno, ovp.op_pages, &omp)) != 0)
return rc2;
ovpages = ovp.op_pages;
/* Is the ov page big enough and from this txn (or a parent)? */
if (ovpages >= dpages && IS_MUTABLE(mc->mc_txn, omp)) {
/* yes, overwrite it. Note in this case we don't
* bother to try shrinking the page if the new data
* is smaller than the overflow threshold.
*/
if (!IS_WRITABLE(mc->mc_txn, omp)) {
if (!IS_DIRTY_NW(mc->mc_txn, omp)) {
rc = mdb_page_unspill(mc->mc_txn, omp, &omp);
if (rc)
return rc;
} else {
/* It is writable only in a parent txn */
size_t sz = (size_t) env->me_psize * ovpages, off;
MDB_page *np = mdb_page_malloc(mc->mc_txn, ovpages, 1);
MDB_ID2 id2;
if (!np)
return ENOMEM;
id2.mid = ovp.op_pgno;
id2.mptr = np;
/* Note - this page is already counted in parent's dirty_room */
rc2 = mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &id2);
mdb_cassert(mc, rc2 == 0);
/* Currently we make the page look as with put() in the
* parent txn, in case the user peeks at MDB_RESERVEd
* or unused parts. Some users treat ovpages specially.
*/
if (!(flags & MDB_RESERVE)) {
/* Skip the part where LMDB will put *data.
* Copy end of page, adjusting alignment so
* compiler may copy words instead of bytes.
*/
off = (PAGEHDRSZ + data->mv_size) & -sizeof(size_t);
memcpy((size_t *)((char *)np + off),
(size_t *)((char *)omp + off), sz - off);
sz = PAGEHDRSZ;
}
memcpy(np, omp, sz); /* Copy beginning of page */
SET_PGTXNID(mc->mc_txn, np);
omp = np;
}
}
SETDSZ(leaf, data->mv_size);
if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = METADATA(omp);
else
memcpy(METADATA(omp), data->mv_data, data->mv_size);
return MDB_SUCCESS;
}
if ((rc2 = mdb_ovpage_free(mc, omp)) != MDB_SUCCESS)
return rc2;
} else if (data->mv_size == olddata.mv_size) {
/* same size, just replace it. Note that we could
* also reuse this node if the new data is smaller,
* but instead we opt to shrink the node in that case.
*/
if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = olddata.mv_data;
else if (!(mc->mc_flags & C_SUB))
memcpy(olddata.mv_data, data->mv_data, data->mv_size);
else {
memcpy(NODEKEY(leaf), key->mv_data, key->mv_size);
goto fix_parent;
}
return MDB_SUCCESS;
}
mdb_node_del(mc, 0);
}
rdata = data;
new_sub:
nflags = flags & NODE_ADD_FLAGS;
nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(env, key, rdata);
if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
if (( flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA )
nflags &= ~MDB_APPEND; /* sub-page may need room to grow */
if (!insert_key)
nflags |= MDB_SPLIT_REPLACE;
rc = mdb_page_split(mc, key, rdata, P_INVALID, nflags);
} else {
/* There is room already in this leaf page. */
rc = mdb_node_add(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, nflags);
if (rc == 0) {
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
unsigned i = mc->mc_top;
MDB_page *mp = mc->mc_pg[i];
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == mc || m3->mc_snum < mc->mc_snum || m3->mc_pg[i] != mp) continue;
if (m3->mc_ki[i] >= mc->mc_ki[i] && insert_key) {
m3->mc_ki[i]++;
}
XCURSOR_REFRESH(m3, i, mp);
}
}
}
if (rc == MDB_SUCCESS) {
/* Now store the actual data in the child DB. Note that we're
* storing the user data in the keys field, so there are strict
* size limits on dupdata. The actual data fields of the child
* DB are all zero size.
*/
if (do_sub) {
int xflags, new_dupdata;
mdb_size_t ecount;
put_sub:
xdata.mv_size = 0;
xdata.mv_data = "";
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (flags == MDB_CURRENT) {
xflags = MDB_CURRENT|MDB_NOSPILL;
} else {
mdb_xcursor_init1(mc, leaf);
xflags = (flags & MDB_NODUPDATA) ?
MDB_NOOVERWRITE|MDB_NOSPILL : MDB_NOSPILL;
}
if (sub_root)
mc->mc_xcursor->mx_cursor.mc_pg[0] = sub_root;
new_dupdata = (int)dkey.mv_size;
/* converted, write the original data first */
if (dkey.mv_size) {
rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, xflags);
if (rc)
goto bad_sub;
/* we've done our job */
dkey.mv_size = 0;
}
if (!(leaf->mn_flags & F_SUBDATA) || sub_root) {
/* Adjust other cursors pointing to mp */
MDB_cursor *m2;
MDB_xcursor *mx = mc->mc_xcursor;
unsigned i = mc->mc_top;
MDB_page *mp = mc->mc_pg[i];
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
if (!(m2->mc_flags & C_INITIALIZED)) continue;
if (m2->mc_pg[i] == mp) {
if (m2->mc_ki[i] == mc->mc_ki[i]) {
mdb_xcursor_init2(m2, mx, new_dupdata);
} else if (!insert_key) {
XCURSOR_REFRESH(m2, i, mp);
}
}
}
}
ecount = mc->mc_xcursor->mx_db.md_entries;
if (flags & MDB_APPENDDUP)
xflags |= MDB_APPEND;
rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, xflags);
if (flags & F_SUBDATA) {
void *db = NODEDATA(leaf);
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
}
insert_data = mc->mc_xcursor->mx_db.md_entries - ecount;
}
/* Increment count unless we just replaced an existing item. */
if (insert_data)
mc->mc_db->md_entries++;
if (insert_key) {
/* Invalidate txn if we created an empty sub-DB */
if (rc)
goto bad_sub;
/* If we succeeded and the key didn't exist before,
* make sure the cursor is marked valid.
*/
mc->mc_flags |= C_INITIALIZED;
}
if (flags & MDB_MULTIPLE) {
if (!rc) {
mcount++;
/* let caller know how many succeeded, if any */
data[1].mv_size = mcount;
if (mcount < dcount) {
data[0].mv_data = (char *)data[0].mv_data + data[0].mv_size;
insert_key = insert_data = 0;
goto more;
}
}
}
return rc;
bad_sub:
if (rc == MDB_KEYEXIST) /* should not happen, we deleted that item */
rc = MDB_PROBLEM;
}
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
int
mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
{
MDB_node *leaf;
MDB_page *mp;
int rc;
if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
if (!(mc->mc_flags & C_INITIALIZED))
return EINVAL;
if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
return MDB_NOTFOUND;
if (!(flags & MDB_NOSPILL) && (rc = mdb_page_spill(mc, NULL, NULL)))
return rc;
rc = mdb_cursor_touch(mc);
if (rc)
return rc;
mp = mc->mc_pg[mc->mc_top];
if (IS_LEAF2(mp))
goto del_key;
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (flags & MDB_NODUPDATA) {
/* mdb_cursor_del0() will subtract the final entry */
mc->mc_db->md_entries -= mc->mc_xcursor->mx_db.md_entries - 1;
mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
} else {
if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
}
rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, MDB_NOSPILL);
if (rc)
return rc;
/* If sub-DB still has entries, we're done */
if (mc->mc_xcursor->mx_db.md_entries) {
if (leaf->mn_flags & F_SUBDATA) {
/* update subDB info */
void *db = NODEDATA(leaf);
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
} else {
MDB_cursor *m2;
/* shrink fake page */
mdb_node_shrink(mp, mc->mc_ki[mc->mc_top]);
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
/* fix other sub-DB cursors pointed at fake pages on this page */
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
if (!(m2->mc_flags & C_INITIALIZED)) continue;
if (m2->mc_pg[mc->mc_top] == mp) {
XCURSOR_REFRESH(m2, mc->mc_top, mp);
}
}
}
mc->mc_db->md_entries--;
return rc;
} else {
mc->mc_xcursor->mx_cursor.mc_flags &= ~C_INITIALIZED;
}
/* otherwise fall thru and delete the sub-DB */
}
if (leaf->mn_flags & F_SUBDATA) {
/* add all the child DB's pages to the free list */
rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
if (rc)
goto fail;
}
}
/* LMDB passes F_SUBDATA in 'flags' to delete a DB record */
else if ((leaf->mn_flags ^ flags) & F_SUBDATA) {
rc = MDB_INCOMPATIBLE;
goto fail;
}
/* add overflow pages to free list */
if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
MDB_page *omp;
MDB_ovpage ovp;
memcpy(&ovp, NODEDATA(leaf), sizeof(ovp));
if ((rc = MDB_PAGE_GET(mc, ovp.op_pgno, ovp.op_pages, &omp)) ||
(rc = mdb_ovpage_free(mc, omp)))
goto fail;
}
del_key:
return mdb_cursor_del0(mc);
fail:
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
/** Allocate and initialize new pages for a database.
* Set #MDB_TXN_ERROR on failure.
* @param[in] mc a cursor on the database being added to.
* @param[in] flags flags defining what type of page is being allocated.
* @param[in] num the number of pages to allocate. This is usually 1,
* unless allocating overflow pages for a large record.
* @param[out] mp Address of a page, or NULL on failure.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_new(MDB_cursor *mc, uint32_t flags, int num, MDB_page **mp)
{
MDB_page *np;
int rc;
if ((rc = mdb_page_alloc(mc, num, &np)))
return rc;
DPRINTF(("allocated new mpage %"Yu", page size %u",
np->mp_pgno, mc->mc_txn->mt_env->me_psize));
np->mp_flags |= flags;
np->mp_lower = (PAGEHDRSZ-PAGEBASE);
np->mp_upper = mc->mc_txn->mt_env->me_psize - PAGEBASE;
#if MDB_RPAGE_CACHE
np->mp_upper -= mc->mc_txn->mt_env->me_sumsize;
np->mp_upper -= mc->mc_txn->mt_env->me_esumsize;
#endif
if (IS_BRANCH(np))
mc->mc_db->md_branch_pages++;
else if (IS_LEAF(np))
mc->mc_db->md_leaf_pages++;
else if (IS_OVERFLOW(np)) {
mc->mc_db->md_overflow_pages += num;
np->mp_pages = num;
}
*mp = np;
return 0;
}
/** Calculate the size of a leaf node.
* The size depends on the environment's page size; if a data item
* is too large it will be put onto an overflow page and the node
* size will only include the key and not the data. Sizes are always
* rounded up to an even number of bytes, to guarantee 2-byte alignment
* of the #MDB_node headers.
* @param[in] env The environment handle.
* @param[in] key The key for the node.
* @param[in] data The data for the node.
* @return The number of bytes needed to store the node.
*/
static size_t
mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
{
size_t sz;
sz = LEAFSIZE(key, data);
if (sz > env->me_nodemax) {
/* put on overflow page */
sz -= data->mv_size - sizeof(MDB_ovpage);
}
return EVEN(sz + sizeof(indx_t));
}
/** Calculate the size of a branch node.
* The size should depend on the environment's page size but since
* we currently don't support spilling large keys onto overflow
* pages, it's simply the size of the #MDB_node header plus the
* size of the key. Sizes are always rounded up to an even number
* of bytes, to guarantee 2-byte alignment of the #MDB_node headers.
* @param[in] env The environment handle.
* @param[in] key The key for the node.
* @return The number of bytes needed to store the node.
*/
static size_t
mdb_branch_size(MDB_env *env, MDB_val *key)
{
size_t sz;
sz = INDXSIZE(key);
if (sz > env->me_nodemax) {
/* put on overflow page */
/* not implemented */
/* sz -= key->size - sizeof(MDB_ovpage); */
}
return sz + sizeof(indx_t);
}
/** Add a node to the page pointed to by the cursor.
* Set #MDB_TXN_ERROR on failure.
* @param[in] mc The cursor for this operation.
* @param[in] indx The index on the page where the new node should be added.
* @param[in] key The key for the new node.
* @param[in] data The data for the new node, if any.
* @param[in] pgno The page number, if adding a branch node.
* @param[in] flags Flags for the node.
* @return 0 on success, non-zero on failure. Possible errors are:
* <ul>
* <li>ENOMEM - failed to allocate overflow pages for the node.
* <li>MDB_PAGE_FULL - there is insufficient room in the page. This error
* should never happen since all callers already calculate the
* page's free space before calling this function.
* </ul>
*/
static int
mdb_node_add(MDB_cursor *mc, indx_t indx,
MDB_val *key, MDB_val *data, pgno_t pgno, unsigned int flags)
{
unsigned int i;
size_t node_size = NODESIZE;
ssize_t room;
indx_t ofs;
MDB_node *node;
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_page *ofp = NULL; /* overflow page */
void *ndata;
DKBUF;
mdb_cassert(mc, mp->mp_upper >= mp->mp_lower);
DPRINTF(("add to %s %spage %"Yu" index %i, data size %"Z"u key size %"Z"u [%s]",
IS_LEAF(mp) ? "leaf" : "branch",
IS_SUBP(mp) ? "sub-" : "",
mdb_dbg_pgno(mp), indx, data ? data->mv_size : 0,
key ? key->mv_size : 0, key ? DKEY(key) : "null"));
if (IS_LEAF2(mp)) {
/* Move higher keys up one slot. */
int ksize = mc->mc_db->md_pad, dif;
char *ptr = LEAF2KEY(mp, indx, ksize);
dif = NUMKEYS(mp) - indx;
if (dif > 0)
memmove(ptr+ksize, ptr, dif*ksize);
/* insert new key */
memcpy(ptr, key->mv_data, ksize);
/* Just using these for counting */
mp->mp_lower += sizeof(indx_t);
mp->mp_upper -= ksize - sizeof(indx_t);
return MDB_SUCCESS;
}
room = (ssize_t)SIZELEFT(mp) - (ssize_t)sizeof(indx_t);
if (key != NULL)
node_size += key->mv_size;
if (IS_LEAF(mp)) {
mdb_cassert(mc, key && data);
if (F_ISSET(flags, F_BIGDATA)) {
/* Data already on overflow page. */
node_size += sizeof(MDB_ovpage);
} else if (node_size + data->mv_size > mc->mc_txn->mt_env->me_nodemax) {
int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
int rc;
/* Put data on overflow page. */
DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",
data->mv_size, node_size+data->mv_size));
node_size = EVEN(node_size + sizeof(MDB_ovpage));
if ((ssize_t)node_size > room)
goto full;
if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
return rc;
DPRINTF(("allocated overflow page %"Yu, ofp->mp_pgno));
flags |= F_BIGDATA;
goto update;
} else {
node_size += data->mv_size;
}
}
node_size = EVEN(node_size);
if ((ssize_t)node_size > room)
goto full;
update:
/* Move higher pointers up one slot. */
for (i = NUMKEYS(mp); i > indx; i--)
mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
/* Adjust free space offsets. */
ofs = mp->mp_upper - node_size;
mdb_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));
mp->mp_ptrs[indx] = ofs;
mp->mp_upper = ofs;
mp->mp_lower += sizeof(indx_t);
/* Write the node data. */
node = NODEPTR(mp, indx);
node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
node->mn_flags = flags;
if (IS_LEAF(mp))
SETDSZ(node,data->mv_size);
else
SETPGNO(node,pgno);
if (key)
memcpy(NODEKEY(node), key->mv_data, key->mv_size);
if (IS_LEAF(mp)) {
ndata = NODEDATA(node);
if (ofp == NULL) {
if (F_ISSET(flags, F_BIGDATA))
memcpy(ndata, data->mv_data, sizeof(MDB_ovpage));
else if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = ndata;
else
memcpy(ndata, data->mv_data, data->mv_size);
} else {
MDB_ovpage ovp;
ovp.op_pgno = ofp->mp_pgno;
ovp.op_txnid = mc->mc_txn->mt_txnid;
ovp.op_pages = ofp->mp_pages;
memcpy(ndata, &ovp, sizeof(MDB_ovpage));
ndata = METADATA(ofp);
if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = ndata;
else
memcpy(ndata, data->mv_data, data->mv_size);
}
}
return MDB_SUCCESS;
full:
DPRINTF(("not enough room in page %"Yu", got %u ptrs",
mdb_dbg_pgno(mp), NUMKEYS(mp)));
DPRINTF(("upper-lower = %u - %u = %"Z"d", mp->mp_upper,mp->mp_lower,room));
DPRINTF(("node size = %"Z"u", node_size));
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return MDB_PAGE_FULL;
}
/** Delete the specified node from a page.
* @param[in] mc Cursor pointing to the node to delete.
* @param[in] ksize The size of a node. Only used if the page is
* part of a #MDB_DUPFIXED database.
*/
static void
mdb_node_del(MDB_cursor *mc, int ksize)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
indx_t indx = mc->mc_ki[mc->mc_top];
unsigned int sz;
indx_t i, j, numkeys, ptr;
MDB_node *node;
char *base;
DPRINTF(("delete node %u on %s page %"Yu, indx,
IS_LEAF(mp) ? "leaf" : "branch", mdb_dbg_pgno(mp)));
numkeys = NUMKEYS(mp);
mdb_cassert(mc, indx < numkeys);
if (IS_LEAF2(mp)) {
int x = numkeys - 1 - indx;
base = LEAF2KEY(mp, indx, ksize);
if (x)
memmove(base, base + ksize, x * ksize);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += ksize - sizeof(indx_t);
return;
}
node = NODEPTR(mp, indx);
sz = NODESIZE + node->mn_ksize;
if (IS_LEAF(mp)) {
if (F_ISSET(node->mn_flags, F_BIGDATA))
sz += sizeof(MDB_ovpage);
else
sz += NODEDSZ(node);
}
sz = EVEN(sz);
ptr = mp->mp_ptrs[indx];
for (i = j = 0; i < numkeys; i++) {
if (i != indx) {
mp->mp_ptrs[j] = mp->mp_ptrs[i];
if (mp->mp_ptrs[i] < ptr)
mp->mp_ptrs[j] += sz;
j++;
}
}
base = (char *)mp + mp->mp_upper + PAGEBASE;
memmove(base + sz, base, ptr - mp->mp_upper);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += sz;
}
/** Compact the main page after deleting a node on a subpage.
* @param[in] mp The main page to operate on.
* @param[in] indx The index of the subpage on the main page.
*/
static void
mdb_node_shrink(MDB_page *mp, indx_t indx)
{
MDB_node *node;
MDB_page *sp, *xp;
char *base;
indx_t delta, nsize, len, ptr;
int i;
node = NODEPTR(mp, indx);
sp = (MDB_page *)NODEDATA(node);
delta = SIZELEFT(sp);
nsize = NODEDSZ(node) - delta;
/* Prepare to shift upward, set len = length(subpage part to shift) */
if (IS_LEAF2(sp)) {
len = nsize;
if (nsize & 1)
return; /* do not make the node uneven-sized */
} else {
xp = (MDB_page *)((char *)sp + delta); /* destination subpage */
for (i = NUMKEYS(sp); --i >= 0; )
xp->mp_ptrs[i] = sp->mp_ptrs[i] - delta;
len = PAGEHDRSZ;
}
sp->mp_upper = sp->mp_lower;
COPY_PGNO(sp->mp_pgno, mp->mp_pgno);
SETDSZ(node, nsize);
/* Shift <lower nodes...initial part of subpage> upward */
base = (char *)mp + mp->mp_upper + PAGEBASE;
memmove(base + delta, base, (char *)sp + len - base);
ptr = mp->mp_ptrs[indx];
for (i = NUMKEYS(mp); --i >= 0; ) {
if (mp->mp_ptrs[i] <= ptr)
mp->mp_ptrs[i] += delta;
}
mp->mp_upper += delta;
}
/** Initial setup of a sorted-dups cursor.
* Sorted duplicates are implemented as a sub-database for the given key.
* The duplicate data items are actually keys of the sub-database.
* Operations on the duplicate data items are performed using a sub-cursor
* initialized when the sub-database is first accessed. This function does
* the preliminary setup of the sub-cursor, filling in the fields that
* depend only on the parent DB.
* @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
*/
static void
mdb_xcursor_init0(MDB_cursor *mc)
{
MDB_xcursor *mx = mc->mc_xcursor;
mx->mx_cursor.mc_xcursor = NULL;
mx->mx_cursor.mc_txn = mc->mc_txn;
mx->mx_cursor.mc_db = &mx->mx_db;
mx->mx_cursor.mc_dbx = &mx->mx_dbx;
mx->mx_cursor.mc_dbi = mc->mc_dbi;
mx->mx_cursor.mc_dbflag = &mx->mx_dbflag;
mx->mx_cursor.mc_snum = 0;
mx->mx_cursor.mc_top = 0;
MC_SET_OVPG(&mx->mx_cursor, NULL);
mx->mx_cursor.mc_flags = C_SUB | (mc->mc_flags & (C_ORIG_RDONLY|C_WRITEMAP));
mx->mx_dbx.md_name.mv_size = 0;
mx->mx_dbx.md_name.mv_data = NULL;
mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp;
mx->mx_dbx.md_dcmp = NULL;
mx->mx_dbx.md_rel = mc->mc_dbx->md_rel;
}
/** Final setup of a sorted-dups cursor.
* Sets up the fields that depend on the data from the main cursor.
* @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
* @param[in] node The data containing the #MDB_db record for the
* sorted-dup database.
*/
static void
mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
{
MDB_xcursor *mx = mc->mc_xcursor;
mx->mx_cursor.mc_flags &= C_SUB|C_ORIG_RDONLY|C_WRITEMAP;
if (node->mn_flags & F_SUBDATA) {
memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
mx->mx_cursor.mc_pg[0] = 0;
mx->mx_cursor.mc_snum = 0;
mx->mx_cursor.mc_top = 0;
} else {
MDB_page *fp = NODEDATA(node);
mx->mx_db.md_pad = 0;
mx->mx_db.md_flags = 0;
mx->mx_db.md_depth = 1;
mx->mx_db.md_branch_pages = 0;
mx->mx_db.md_leaf_pages = 1;
mx->mx_db.md_overflow_pages = 0;
mx->mx_db.md_entries = NUMKEYS(fp);
COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
mx->mx_cursor.mc_snum = 1;
mx->mx_cursor.mc_top = 0;
mx->mx_cursor.mc_flags |= C_INITIALIZED;
mx->mx_cursor.mc_pg[0] = fp;
mx->mx_cursor.mc_ki[0] = 0;
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
mx->mx_db.md_flags = MDB_DUPFIXED;
mx->mx_db.md_pad = fp->mp_pad;
if (mc->mc_db->md_flags & MDB_INTEGERDUP)
mx->mx_db.md_flags |= MDB_INTEGERKEY;
}
}
DPRINTF(("Sub-db -%u root page %"Yu, mx->mx_cursor.mc_dbi,
mx->mx_db.md_root));
mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DUPDATA;
if (NEED_CMP_CLONG(mx->mx_dbx.md_cmp, mx->mx_db.md_pad))
mx->mx_dbx.md_cmp = mdb_cmp_clong;
}
/** Fixup a sorted-dups cursor due to underlying update.
* Sets up some fields that depend on the data from the main cursor.
* Almost the same as init1, but skips initialization steps if the
* xcursor had already been used.
* @param[in] mc The main cursor whose sorted-dups cursor is to be fixed up.
* @param[in] src_mx The xcursor of an up-to-date cursor.
* @param[in] new_dupdata True if converting from a non-#F_DUPDATA item.
*/
static void
mdb_xcursor_init2(MDB_cursor *mc, MDB_xcursor *src_mx, int new_dupdata)
{
MDB_xcursor *mx = mc->mc_xcursor;
if (new_dupdata) {
mx->mx_cursor.mc_snum = 1;
mx->mx_cursor.mc_top = 0;
mx->mx_cursor.mc_flags |= C_INITIALIZED;
mx->mx_cursor.mc_ki[0] = 0;
mx->mx_dbflag = DB_VALID|DB_USRVALID|DB_DUPDATA;
#if UINT_MAX < MDB_SIZE_MAX /* matches mdb_xcursor_init1:NEED_CMP_CLONG() */
mx->mx_dbx.md_cmp = src_mx->mx_dbx.md_cmp;
#endif
} else if (!(mx->mx_cursor.mc_flags & C_INITIALIZED)) {
return;
}
mx->mx_db = src_mx->mx_db;
mx->mx_cursor.mc_pg[0] = src_mx->mx_cursor.mc_pg[0];
DPRINTF(("Sub-db -%u root page %"Yu, mx->mx_cursor.mc_dbi,
mx->mx_db.md_root));
}
/** Initialize a cursor for a given transaction and database. */
static void
mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
{
mc->mc_next = NULL;
mc->mc_backup = NULL;
mc->mc_dbi = dbi;
mc->mc_txn = txn;
mc->mc_db = &txn->mt_dbs[dbi];
mc->mc_dbx = &txn->mt_dbxs[dbi];
mc->mc_dbflag = &txn->mt_dbflags[dbi];
mc->mc_snum = 0;
mc->mc_top = 0;
mc->mc_pg[0] = 0;
mc->mc_ki[0] = 0;
MC_SET_OVPG(mc, NULL);
mc->mc_flags = txn->mt_flags & (C_ORIG_RDONLY|C_WRITEMAP);
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
mdb_tassert(txn, mx != NULL);
mc->mc_xcursor = mx;
mdb_xcursor_init0(mc);
} else {
mc->mc_xcursor = NULL;
}
if (*mc->mc_dbflag & DB_STALE) {
mdb_page_search(mc, NULL, MDB_PS_ROOTONLY);
}
}
int
mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
{
MDB_cursor *mc;
size_t size = sizeof(MDB_cursor);
if (!ret || !TXN_DBI_EXIST(txn, dbi, DB_VALID))
return EINVAL;
if (txn->mt_flags & MDB_TXN_BLOCKED)
return MDB_BAD_TXN;
if (dbi == FREE_DBI && !F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
return EINVAL;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
size += sizeof(MDB_xcursor);
if ((mc = malloc(size)) != NULL) {
mdb_cursor_init(mc, txn, dbi, (MDB_xcursor *)(mc + 1));
if (txn->mt_cursors) {
mc->mc_next = txn->mt_cursors[dbi];
txn->mt_cursors[dbi] = mc;
mc->mc_flags |= C_UNTRACK;
}
} else {
return ENOMEM;
}
*ret = mc;
return MDB_SUCCESS;
}
int
mdb_cursor_renew(MDB_txn *txn, MDB_cursor *mc)
{
if (!mc || !TXN_DBI_EXIST(txn, mc->mc_dbi, DB_VALID))
return EINVAL;
if ((mc->mc_flags & C_UNTRACK) || txn->mt_cursors)
return EINVAL;
if (txn->mt_flags & MDB_TXN_BLOCKED)
return MDB_BAD_TXN;
mdb_cursor_init(mc, txn, mc->mc_dbi, mc->mc_xcursor);
return MDB_SUCCESS;
}
/* Return the count of duplicate data items for the current key */
int
mdb_cursor_count(MDB_cursor *mc, mdb_size_t *countp)
{
MDB_node *leaf;
if (mc == NULL || countp == NULL)
return EINVAL;
if (mc->mc_xcursor == NULL)
return MDB_INCOMPATIBLE;
if (mc->mc_txn->mt_flags & MDB_TXN_BLOCKED)
return MDB_BAD_TXN;
if (!(mc->mc_flags & C_INITIALIZED))
return EINVAL;
if (!mc->mc_snum)
return MDB_NOTFOUND;
if (mc->mc_flags & C_EOF) {
if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
return MDB_NOTFOUND;
mc->mc_flags ^= C_EOF;
}
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
*countp = 1;
} else {
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
return EINVAL;
*countp = mc->mc_xcursor->mx_db.md_entries;
}
return MDB_SUCCESS;
}
void
mdb_cursor_close(MDB_cursor *mc)
{
if (mc) {
MDB_CURSOR_UNREF(mc, 0);
}
if (mc && !mc->mc_backup) {
/* Remove from txn, if tracked.
* A read-only txn (!C_UNTRACK) may have been freed already,
* so do not peek inside it. Only write txns track cursors.
*/
if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
while (*prev && *prev != mc) prev = &(*prev)->mc_next;
if (*prev == mc)
*prev = mc->mc_next;
}
free(mc);
}
}
MDB_txn *
mdb_cursor_txn(MDB_cursor *mc)
{
if (!mc) return NULL;
return mc->mc_txn;
}
MDB_dbi
mdb_cursor_dbi(MDB_cursor *mc)
{
return mc->mc_dbi;
}
int
mdb_cursor_is_db(MDB_cursor *mc)
{
if (mc && (mc->mc_flags & C_INITIALIZED) && mc->mc_snum) {
MDB_node *leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if ((leaf->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_SUBDATA)
return 1;
}
return 0;
}
/** Replace the key for a branch node with a new key.
* Set #MDB_TXN_ERROR on failure.
* @param[in] mc Cursor pointing to the node to operate on.
* @param[in] key The new key to use.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_update_key(MDB_cursor *mc, MDB_val *key)
{
MDB_page *mp;
MDB_node *node;
char *base;
size_t len;
int delta, ksize, oksize;
indx_t ptr, i, numkeys, indx;
DKBUF;
indx = mc->mc_ki[mc->mc_top];
mp = mc->mc_pg[mc->mc_top];
node = NODEPTR(mp, indx);
ptr = mp->mp_ptrs[indx];
#if MDB_DEBUG
{
MDB_val k2;
char kbuf2[DKBUF_MAXKEYSIZE*2+1];
k2.mv_data = NODEKEY(node);
k2.mv_size = node->mn_ksize;
DPRINTF(("update key %u (ofs %u) [%s] to [%s] on page %"Yu,
indx, ptr,
mdb_dkey(&k2, kbuf2),
DKEY(key),
mp->mp_pgno));
}
#endif
/* Sizes must be 2-byte aligned. */
ksize = EVEN(key->mv_size);
oksize = EVEN(node->mn_ksize);
delta = ksize - oksize;
/* Shift node contents if EVEN(key length) changed. */
if (delta) {
if (delta > 0 && SIZELEFT(mp) < delta) {
pgno_t pgno;
/* not enough space left, do a delete and split */
DPRINTF(("Not enough room, delta = %d, splitting...", delta));
pgno = NODEPGNO(node);
mdb_node_del(mc, 0);
return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);
}
numkeys = NUMKEYS(mp);
for (i = 0; i < numkeys; i++) {
if (mp->mp_ptrs[i] <= ptr)
mp->mp_ptrs[i] -= delta;
}
base = (char *)mp + mp->mp_upper + PAGEBASE;
len = ptr - mp->mp_upper + NODESIZE;
memmove(base - delta, base, len);
mp->mp_upper -= delta;
node = NODEPTR(mp, indx);
}
/* But even if no shift was needed, update ksize */
if (node->mn_ksize != key->mv_size)
node->mn_ksize = key->mv_size;
if (key->mv_size)
memcpy(NODEKEY(node), key->mv_data, key->mv_size);
return MDB_SUCCESS;
}
static void
mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst);
/** Perform \b act while tracking temporary cursor \b mn */
#define WITH_CURSOR_TRACKING(mn, act) do { \
MDB_cursor dummy, *tracked, **tp = &(mn).mc_txn->mt_cursors[mn.mc_dbi]; \
if ((mn).mc_flags & C_SUB) { \
dummy.mc_flags = C_INITIALIZED; \
dummy.mc_xcursor = (MDB_xcursor *)&(mn); \
tracked = &dummy; \
} else { \
tracked = &(mn); \
} \
tracked->mc_next = *tp; \
*tp = tracked; \
{ act; } \
*tp = tracked->mc_next; \
} while (0)
/** Move a node from csrc to cdst.
*/
static int
mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft)
{
MDB_node *srcnode;
MDB_val key, data;
pgno_t srcpg;
MDB_cursor mn;
int rc;
unsigned short flags;
DKBUF;
/* Mark src and dst as dirty. */
if ((rc = mdb_page_touch(csrc)) ||
(rc = mdb_page_touch(cdst)))
return rc;
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
data.mv_size = 0;
data.mv_data = NULL;
srcpg = 0;
flags = 0;
} else {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
mdb_cassert(csrc, !((size_t)srcnode & 1));
srcpg = NODEPGNO(srcnode);
flags = srcnode->mn_flags;
if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
unsigned int snum = csrc->mc_snum;
MDB_node *s2;
/* must find the lowest key below src */
rc = mdb_page_search_lowest(csrc);
if (rc)
return rc;
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(s2);
key.mv_data = NODEKEY(s2);
}
csrc->mc_snum = snum--;
csrc->mc_top = snum;
} else {
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
data.mv_size = NODEDSZ(srcnode);
data.mv_data = NODEDATA(srcnode);
}
mn.mc_xcursor = NULL;
if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
unsigned int snum = cdst->mc_snum;
MDB_node *s2;
MDB_val bkey;
/* must find the lowest key below dst */
mdb_cursor_copy(cdst, &mn);
rc = mdb_page_search_lowest(&mn);
if (rc)
return rc;
if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
bkey.mv_size = mn.mc_db->md_pad;
bkey.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, bkey.mv_size);
} else {
s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
bkey.mv_size = NODEKSZ(s2);
bkey.mv_data = NODEKEY(s2);
}
mn.mc_snum = snum--;
mn.mc_top = snum;
mn.mc_ki[snum] = 0;
rc = mdb_update_key(&mn, &bkey);
if (rc)
return rc;
}
DPRINTF(("moving %s node %u [%s] on page %"Yu" to node %u on page %"Yu,
IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
csrc->mc_ki[csrc->mc_top],
DKEY(&key),
csrc->mc_pg[csrc->mc_top]->mp_pgno,
cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno));
/* Add the node to the destination page.
*/
rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
if (rc != MDB_SUCCESS)
return rc;
/* Delete the node from the source page.
*/
mdb_node_del(csrc, key.mv_size);
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = csrc->mc_dbi;
MDB_page *mpd, *mps;
mps = csrc->mc_pg[csrc->mc_top];
/* If we're adding on the left, bump others up */
if (fromleft) {
mpd = cdst->mc_pg[csrc->mc_top];
for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (csrc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)
continue;
if (m3 != cdst &&
m3->mc_pg[csrc->mc_top] == mpd &&
m3->mc_ki[csrc->mc_top] >= cdst->mc_ki[csrc->mc_top]) {
m3->mc_ki[csrc->mc_top]++;
}
if (m3 !=csrc &&
m3->mc_pg[csrc->mc_top] == mps &&
m3->mc_ki[csrc->mc_top] == csrc->mc_ki[csrc->mc_top]) {
m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
m3->mc_ki[csrc->mc_top-1]++;
}
if (IS_LEAF(mps))
XCURSOR_REFRESH(m3, csrc->mc_top, m3->mc_pg[csrc->mc_top]);
}
} else
/* Adding on the right, bump others down */
{
for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (csrc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == csrc) continue;
if (!(m3->mc_flags & C_INITIALIZED) || m3->mc_top < csrc->mc_top)
continue;
if (m3->mc_pg[csrc->mc_top] == mps) {
if (!m3->mc_ki[csrc->mc_top]) {
m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
m3->mc_ki[csrc->mc_top-1]--;
} else {
m3->mc_ki[csrc->mc_top]--;
}
if (IS_LEAF(mps))
XCURSOR_REFRESH(m3, csrc->mc_top, m3->mc_pg[csrc->mc_top]);
}
}
}
}
/* Update the parent separators.
*/
if (csrc->mc_ki[csrc->mc_top] == 0) {
if (csrc->mc_ki[csrc->mc_top-1] != 0) {
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
DPRINTF(("update separator for source page %"Yu" to [%s]",
csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key)));
mdb_cursor_copy(csrc, &mn);
mn.mc_snum--;
mn.mc_top--;
/* We want mdb_rebalance to find mn when doing fixups */
WITH_CURSOR_TRACKING(mn,
rc = mdb_update_key(&mn, &key));
if (rc)
return rc;
}
if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
MDB_val nullkey;
indx_t ix = csrc->mc_ki[csrc->mc_top];
nullkey.mv_size = 0;
csrc->mc_ki[csrc->mc_top] = 0;
rc = mdb_update_key(csrc, &nullkey);
csrc->mc_ki[csrc->mc_top] = ix;
mdb_cassert(csrc, rc == MDB_SUCCESS);
}
}
if (cdst->mc_ki[cdst->mc_top] == 0) {
if (cdst->mc_ki[cdst->mc_top-1] != 0) {
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
} else {
srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
DPRINTF(("update separator for destination page %"Yu" to [%s]",
cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key)));
mdb_cursor_copy(cdst, &mn);
mn.mc_snum--;
mn.mc_top--;
/* We want mdb_rebalance to find mn when doing fixups */
WITH_CURSOR_TRACKING(mn,
rc = mdb_update_key(&mn, &key));
if (rc)
return rc;
}
if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
MDB_val nullkey;
indx_t ix = cdst->mc_ki[cdst->mc_top];
nullkey.mv_size = 0;
cdst->mc_ki[cdst->mc_top] = 0;
rc = mdb_update_key(cdst, &nullkey);
cdst->mc_ki[cdst->mc_top] = ix;
mdb_cassert(cdst, rc == MDB_SUCCESS);
}
}
return MDB_SUCCESS;
}
/** Merge one page into another.
* The nodes from the page pointed to by \b csrc will
* be copied to the page pointed to by \b cdst and then
* the \b csrc page will be freed.
* @param[in] csrc Cursor pointing to the source page.
* @param[in] cdst Cursor pointing to the destination page.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
{
MDB_page *psrc, *pdst;
MDB_node *srcnode;
MDB_val key, data;
unsigned nkeys;
int rc;
indx_t i, j;
psrc = csrc->mc_pg[csrc->mc_top];
pdst = cdst->mc_pg[cdst->mc_top];
DPRINTF(("merging page %"Yu" into %"Yu, psrc->mp_pgno, pdst->mp_pgno));
mdb_cassert(csrc, csrc->mc_snum > 1); /* can't merge root page */
mdb_cassert(csrc, cdst->mc_snum > 1);
/* Mark dst as dirty. */
if ((rc = mdb_page_touch(cdst)))
return rc;
/* get dst page again now that we've touched it. */
pdst = cdst->mc_pg[cdst->mc_top];
/* Move all nodes from src to dst.
*/
j = nkeys = NUMKEYS(pdst);
if (IS_LEAF2(psrc)) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = METADATA(psrc);
for (i = 0; i < NUMKEYS(psrc); i++, j++) {
rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
if (rc != MDB_SUCCESS)
return rc;
key.mv_data = (char *)key.mv_data + key.mv_size;
}
} else {
for (i = 0; i < NUMKEYS(psrc); i++, j++) {
srcnode = NODEPTR(psrc, i);
if (i == 0 && IS_BRANCH(psrc)) {
MDB_cursor mn;
MDB_node *s2;
mdb_cursor_copy(csrc, &mn);
mn.mc_xcursor = NULL;
/* must find the lowest key below src */
rc = mdb_page_search_lowest(&mn);
if (rc)
return rc;
if (IS_LEAF2(mn.mc_pg[mn.mc_top])) {
key.mv_size = mn.mc_db->md_pad;
key.mv_data = LEAF2KEY(mn.mc_pg[mn.mc_top], 0, key.mv_size);
} else {
s2 = NODEPTR(mn.mc_pg[mn.mc_top], 0);
key.mv_size = NODEKSZ(s2);
key.mv_data = NODEKEY(s2);
}
} else {
key.mv_size = srcnode->mn_ksize;
key.mv_data = NODEKEY(srcnode);
}
data.mv_size = NODEDSZ(srcnode);
data.mv_data = NODEDATA(srcnode);
rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
if (rc != MDB_SUCCESS)
return rc;
}
}
DPRINTF(("dst page %"Yu" now has %u keys (%.1f%% filled)",
pdst->mp_pgno, NUMKEYS(pdst),
(float)PAGEFILL(cdst->mc_txn->mt_env, pdst) / 10));
/* Unlink the src page from parent and add to free list.
*/
csrc->mc_top--;
mdb_node_del(csrc, 0);
if (csrc->mc_ki[csrc->mc_top] == 0) {
key.mv_size = 0;
rc = mdb_update_key(csrc, &key);
if (rc) {
csrc->mc_top++;
return rc;
}
}
csrc->mc_top++;
psrc = csrc->mc_pg[csrc->mc_top];
/* If not operating on FreeDB, allow this page to be reused
* in this txn. Otherwise just add to free list.
*/
rc = mdb_page_loose(csrc, psrc);
if (rc)
return rc;
if (IS_LEAF(psrc))
csrc->mc_db->md_leaf_pages--;
else
csrc->mc_db->md_branch_pages--;
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = csrc->mc_dbi;
unsigned int top = csrc->mc_top;
for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (csrc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == csrc) continue;
if (m3->mc_snum < csrc->mc_snum) continue;
if (m3->mc_pg[top] == psrc) {
m3->mc_pg[top] = pdst;
m3->mc_ki[top] += nkeys;
m3->mc_ki[top-1] = cdst->mc_ki[top-1];
} else if (m3->mc_pg[top-1] == csrc->mc_pg[top-1] &&
m3->mc_ki[top-1] > csrc->mc_ki[top-1]) {
m3->mc_ki[top-1]--;
}
if (IS_LEAF(psrc))
XCURSOR_REFRESH(m3, top, m3->mc_pg[top]);
}
}
{
unsigned int snum = cdst->mc_snum;
uint16_t depth = cdst->mc_db->md_depth;
mdb_cursor_pop(cdst);
rc = mdb_rebalance(cdst);
/* Did the tree height change? */
if (depth != cdst->mc_db->md_depth)
snum += cdst->mc_db->md_depth - depth;
cdst->mc_snum = snum;
cdst->mc_top = snum-1;
}
return rc;
}
/** Copy the contents of a cursor.
* @param[in] csrc The cursor to copy from.
* @param[out] cdst The cursor to copy to.
*/
static void
mdb_cursor_copy(const MDB_cursor *csrc, MDB_cursor *cdst)
{
unsigned int i;
cdst->mc_txn = csrc->mc_txn;
cdst->mc_dbi = csrc->mc_dbi;
cdst->mc_db = csrc->mc_db;
cdst->mc_dbx = csrc->mc_dbx;
cdst->mc_snum = csrc->mc_snum;
cdst->mc_top = csrc->mc_top;
cdst->mc_flags = csrc->mc_flags;
MC_SET_OVPG(cdst, MC_OVPG(csrc));
for (i=0; i<csrc->mc_snum; i++) {
cdst->mc_pg[i] = csrc->mc_pg[i];
cdst->mc_ki[i] = csrc->mc_ki[i];
}
}
/** Rebalance the tree after a delete operation.
* @param[in] mc Cursor pointing to the page where rebalancing
* should begin.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_rebalance(MDB_cursor *mc)
{
MDB_node *node;
int rc, fromleft;
unsigned int ptop, minkeys, thresh;
MDB_cursor mn;
indx_t oldki;
if (IS_BRANCH(mc->mc_pg[mc->mc_top])) {
minkeys = 2;
thresh = 1;
} else {
minkeys = 1;
thresh = FILL_THRESHOLD;
}
DPRINTF(("rebalancing %s page %"Yu" (has %u keys, %.1f%% full)",
IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
mdb_dbg_pgno(mc->mc_pg[mc->mc_top]), NUMKEYS(mc->mc_pg[mc->mc_top]),
(float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10));
if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= thresh &&
NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
DPRINTF(("no need to rebalance page %"Yu", above fill threshold",
mdb_dbg_pgno(mc->mc_pg[mc->mc_top])));
return MDB_SUCCESS;
}
if (mc->mc_snum < 2) {
MDB_page *mp = mc->mc_pg[0];
if (IS_SUBP(mp)) {
DPUTS("Can't rebalance a subpage, ignoring");
return MDB_SUCCESS;
}
if (NUMKEYS(mp) == 0) {
DPUTS("tree is completely empty");
mc->mc_db->md_root = P_INVALID;
mc->mc_db->md_depth = 0;
mc->mc_db->md_leaf_pages = 0;
rc = mdb_page_loose(mc, mp);
if (rc)
return rc;
/* Adjust cursors pointing to mp */
mc->mc_snum = 0;
mc->mc_top = 0;
mc->mc_flags &= ~C_INITIALIZED;
{
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (!(m3->mc_flags & C_INITIALIZED) || (m3->mc_snum < mc->mc_snum))
continue;
if (m3->mc_pg[0] == mp) {
m3->mc_snum = 0;
m3->mc_top = 0;
m3->mc_flags &= ~C_INITIALIZED;
}
}
}
} else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
int i;
DPUTS("collapsing root page!");
rc = mdb_page_loose(mc, mp);
if (rc)
return rc;
mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
rc = MDB_PAGE_GET(mc, mc->mc_db->md_root, 1, &mc->mc_pg[0]);
if (rc)
return rc;
mc->mc_db->md_depth--;
mc->mc_db->md_branch_pages--;
mc->mc_ki[0] = mc->mc_ki[1];
for (i = 1; i<mc->mc_db->md_depth; i++) {
mc->mc_pg[i] = mc->mc_pg[i+1];
mc->mc_ki[i] = mc->mc_ki[i+1];
}
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == mc) continue;
if (!(m3->mc_flags & C_INITIALIZED))
continue;
if (m3->mc_pg[0] == mp) {
for (i=0; i<mc->mc_db->md_depth; i++) {
m3->mc_pg[i] = m3->mc_pg[i+1];
m3->mc_ki[i] = m3->mc_ki[i+1];
}
m3->mc_snum--;
m3->mc_top--;
}
}
}
} else
DPUTS("root page doesn't need rebalancing");
return MDB_SUCCESS;
}
/* The parent (branch page) must have at least 2 pointers,
* otherwise the tree is invalid.
*/
ptop = mc->mc_top-1;
mdb_cassert(mc, NUMKEYS(mc->mc_pg[ptop]) > 1);
/* Leaf page fill factor is below the threshold.
* Try to move keys from left or right neighbor, or
* merge with a neighbor page.
*/
/* Find neighbors.
*/
mdb_cursor_copy(mc, &mn);
mn.mc_xcursor = NULL;
oldki = mc->mc_ki[mc->mc_top];
if (mc->mc_ki[ptop] == 0) {
/* We're the leftmost leaf in our parent.
*/
DPUTS("reading right neighbor");
mn.mc_ki[ptop]++;
node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
rc = MDB_PAGE_GET(mc, NODEPGNO(node), 1, &mn.mc_pg[mn.mc_top]);
if (rc)
return rc;
mn.mc_ki[mn.mc_top] = 0;
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
fromleft = 0;
} else {
/* There is at least one neighbor to the left.
*/
DPUTS("reading left neighbor");
mn.mc_ki[ptop]--;
node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
rc = MDB_PAGE_GET(mc, NODEPGNO(node), 1, &mn.mc_pg[mn.mc_top]);
if (rc)
return rc;
mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
mc->mc_ki[mc->mc_top] = 0;
fromleft = 1;
}
DPRINTF(("found neighbor page %"Yu" (%u keys, %.1f%% full)",
mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]),
(float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10));
/* If the neighbor page is above threshold and has enough keys,
* move one key from it. Otherwise we should try to merge them.
* (A branch page must never have less than 2 keys.)
*/
if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= thresh && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys) {
rc = mdb_node_move(&mn, mc, fromleft);
if (fromleft) {
/* if we inserted on left, bump position up */
oldki++;
}
} else {
if (!fromleft) {
rc = mdb_page_merge(&mn, mc);
} else {
oldki += NUMKEYS(mn.mc_pg[mn.mc_top]);
mn.mc_ki[mn.mc_top] += mc->mc_ki[mn.mc_top] + 1;
/* We want mdb_rebalance to find mn when doing fixups */
WITH_CURSOR_TRACKING(mn,
rc = mdb_page_merge(mc, &mn));
mdb_cursor_copy(&mn, mc);
}
mc->mc_flags &= ~C_EOF;
}
mc->mc_ki[mc->mc_top] = oldki;
return rc;
}
/** Complete a delete operation started by #mdb_cursor_del(). */
static int
mdb_cursor_del0(MDB_cursor *mc)
{
int rc;
MDB_page *mp;
indx_t ki;
unsigned int nkeys;
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
ki = mc->mc_ki[mc->mc_top];
mp = mc->mc_pg[mc->mc_top];
mdb_node_del(mc, mc->mc_db->md_pad);
mc->mc_db->md_entries--;
{
/* Adjust other cursors pointing to mp */
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))
continue;
if (m3 == mc || m3->mc_snum < mc->mc_snum)
continue;
if (m3->mc_pg[mc->mc_top] == mp) {
if (m3->mc_ki[mc->mc_top] == ki) {
m3->mc_flags |= C_DEL;
if (mc->mc_db->md_flags & MDB_DUPSORT) {
/* Sub-cursor referred into dataset which is gone */
m3->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
}
continue;
} else if (m3->mc_ki[mc->mc_top] > ki) {
m3->mc_ki[mc->mc_top]--;
}
XCURSOR_REFRESH(m3, mc->mc_top, mp);
}
}
}
rc = mdb_rebalance(mc);
if (rc == MDB_SUCCESS) {
/* DB is totally empty now, just bail out.
* Other cursors adjustments were already done
* by mdb_rebalance and aren't needed here.
*/
if (!mc->mc_snum)
return rc;
mp = mc->mc_pg[mc->mc_top];
nkeys = NUMKEYS(mp);
/* Adjust other cursors pointing to mp */
for (m2 = mc->mc_txn->mt_cursors[dbi]; !rc && m2; m2=m2->mc_next) {
m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))
continue;
if (m3->mc_snum < mc->mc_snum)
continue;
if (m3->mc_pg[mc->mc_top] == mp) {
/* if m3 points past last node in page, find next sibling */
if (m3->mc_ki[mc->mc_top] >= mc->mc_ki[mc->mc_top]) {
if (m3->mc_ki[mc->mc_top] >= nkeys) {
rc = mdb_cursor_sibling(m3, 1);
if (rc == MDB_NOTFOUND) {
m3->mc_flags |= C_EOF;
rc = MDB_SUCCESS;
continue;
}
}
if (mc->mc_db->md_flags & MDB_DUPSORT) {
MDB_node *node = NODEPTR(m3->mc_pg[m3->mc_top], m3->mc_ki[m3->mc_top]);
/* If this node has dupdata, it may need to be reinited
* because its data has moved.
* If the xcursor was not initd it must be reinited.
* Else if node points to a subDB, nothing is needed.
* Else (xcursor was initd, not a subDB) needs mc_pg[0] reset.
*/
if (node->mn_flags & F_DUPDATA) {
if (m3->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
if (!(node->mn_flags & F_SUBDATA))
m3->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(node);
} else {
mdb_xcursor_init1(m3, node);
m3->mc_xcursor->mx_cursor.mc_flags |= C_DEL;
}
}
}
}
}
}
mc->mc_flags |= C_DEL;
}
if (rc)
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
int
mdb_del(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data)
{
if (!key || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
if (!F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
/* must ignore any data */
data = NULL;
}
return mdb_del0(txn, dbi, key, data, 0);
}
static int
mdb_del0(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data, unsigned flags)
{
MDB_cursor mc;
MDB_xcursor mx;
MDB_cursor_op op;
MDB_val rdata, *xdata;
int rc, exact = 0;
DKBUF;
DPRINTF(("====> delete db %u key [%s]", dbi, DKEY(key)));
mdb_cursor_init(&mc, txn, dbi, &mx);
if (data) {
op = MDB_GET_BOTH;
rdata = *data;
xdata = &rdata;
} else {
op = MDB_SET;
xdata = NULL;
flags |= MDB_NODUPDATA;
}
rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
if (rc == 0) {
/* let mdb_page_split know about this cursor if needed:
* delete will trigger a rebalance; if it needs to move
* a node from one page to another, it will have to
* update the parent's separator key(s). If the new sepkey
* is larger than the current one, the parent page may
* run out of space, triggering a split. We need this
* cursor to be consistent until the end of the rebalance.
*/
mc.mc_next = txn->mt_cursors[dbi];
txn->mt_cursors[dbi] = &mc;
rc = mdb_cursor_del(&mc, flags);
txn->mt_cursors[dbi] = mc.mc_next;
}
return rc;
}
/** Split a page and insert a new node.
* Set #MDB_TXN_ERROR on failure.
* @param[in,out] mc Cursor pointing to the page and desired insertion index.
* The cursor will be updated to point to the actual page and index where
* the node got inserted after the split.
* @param[in] newkey The key for the newly inserted node.
* @param[in] newdata The data for the newly inserted node.
* @param[in] newpgno The page number, if the new node is a branch node.
* @param[in] nflags The #NODE_ADD_FLAGS for the new node.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno,
unsigned int nflags)
{
unsigned int flags;
int rc = MDB_SUCCESS, new_root = 0, did_split = 0;
indx_t newindx;
pgno_t pgno = 0;
int i, j, split_indx, nkeys, pmax;
MDB_env *env = mc->mc_txn->mt_env;
MDB_node *node;
MDB_val sepkey, rkey, xdata, *rdata = &xdata;
MDB_page *copy = NULL;
MDB_page *mp, *rp, *pp;
int ptop;
MDB_cursor mn;
DKBUF;
mp = mc->mc_pg[mc->mc_top];
newindx = mc->mc_ki[mc->mc_top];
nkeys = NUMKEYS(mp);
DPRINTF(("-----> splitting %s page %"Yu" and adding [%s] at index %i/%i",
IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
DKEY(newkey), mc->mc_ki[mc->mc_top], nkeys));
/* Create a right sibling. */
rc = mdb_page_new(mc, mp->mp_flags & (P_BRANCH|P_LEAF|P_LEAF2), 1, &rp);
if (rc)
return rc;
rp->mp_pad = mp->mp_pad;
DPRINTF(("new right sibling: page %"Yu, rp->mp_pgno));
/* Usually when splitting the root page, the cursor
* height is 1. But when called from mdb_update_key,
* the cursor height may be greater because it walks
* up the stack while finding the branch slot to update.
*/
if (mc->mc_top < 1) {
if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
goto done;
/* shift current top to make room for new parent */
for (i=mc->mc_snum; i>0; i--) {
mc->mc_pg[i] = mc->mc_pg[i-1];
mc->mc_ki[i] = mc->mc_ki[i-1];
}
mc->mc_pg[0] = pp;
mc->mc_ki[0] = 0;
mc->mc_db->md_root = pp->mp_pgno;
DPRINTF(("root split! new root = %"Yu, pp->mp_pgno));
new_root = mc->mc_db->md_depth++;
/* Add left (implicit) pointer. */
if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
/* undo the pre-push */
mc->mc_pg[0] = mc->mc_pg[1];
mc->mc_ki[0] = mc->mc_ki[1];
mc->mc_db->md_root = mp->mp_pgno;
mc->mc_db->md_depth--;
goto done;
}
mc->mc_snum++;
mc->mc_top++;
ptop = 0;
} else {
ptop = mc->mc_top-1;
DPRINTF(("parent branch page is %"Yu, mc->mc_pg[ptop]->mp_pgno));
}
mdb_cursor_copy(mc, &mn);
mn.mc_xcursor = NULL;
mn.mc_pg[mn.mc_top] = rp;
mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
if (nflags & MDB_APPEND) {
mn.mc_ki[mn.mc_top] = 0;
sepkey = *newkey;
split_indx = newindx;
nkeys = 0;
} else {
split_indx = (nkeys+1) / 2;
if (IS_LEAF2(rp)) {
char *split, *ins;
int x;
unsigned int lsize, rsize, ksize;
/* Move half of the keys to the right sibling */
x = mc->mc_ki[mc->mc_top] - split_indx;
ksize = mc->mc_db->md_pad;
split = LEAF2KEY(mp, split_indx, ksize);
rsize = (nkeys - split_indx) * ksize;
lsize = (nkeys - split_indx) * sizeof(indx_t);
mp->mp_lower -= lsize;
rp->mp_lower += lsize;
mp->mp_upper += rsize - lsize;
rp->mp_upper -= rsize - lsize;
sepkey.mv_size = ksize;
if (newindx == split_indx) {
sepkey.mv_data = newkey->mv_data;
} else {
sepkey.mv_data = split;
}
if (x<0) {
ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
memcpy(rp->mp_ptrs, split, rsize);
sepkey.mv_data = rp->mp_ptrs;
memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
memcpy(ins, newkey->mv_data, ksize);
mp->mp_lower += sizeof(indx_t);
mp->mp_upper -= ksize - sizeof(indx_t);
} else {
if (x)
memcpy(rp->mp_ptrs, split, x * ksize);
ins = LEAF2KEY(rp, x, ksize);
memcpy(ins, newkey->mv_data, ksize);
memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
rp->mp_lower += sizeof(indx_t);
rp->mp_upper -= ksize - sizeof(indx_t);
mc->mc_ki[mc->mc_top] = x;
}
} else {
int psize, nsize, k;
/* Maximum free space in an empty page */
pmax = env->me_psize - PAGEHDRSZ;
if (IS_LEAF(mp))
nsize = mdb_leaf_size(env, newkey, newdata);
else
nsize = mdb_branch_size(env, newkey);
nsize = EVEN(nsize);
/* grab a page to hold a temporary copy */
copy = mdb_page_malloc(mc->mc_txn, 1, 1);
if (copy == NULL) {
rc = ENOMEM;
goto done;
}
copy->mp_pgno = mp->mp_pgno;
copy->mp_flags = mp->mp_flags;
copy->mp_lower = (PAGEHDRSZ-PAGEBASE);
copy->mp_upper = env->me_psize - PAGEBASE;
/* prepare to insert */
for (i=0, j=0; i<nkeys; i++) {
if (i == newindx) {
copy->mp_ptrs[j++] = 0;
}
copy->mp_ptrs[j++] = mp->mp_ptrs[i];
}
/* When items are relatively large the split point needs
* to be checked, because being off-by-one will make the
* difference between success or failure in mdb_node_add.
*
* It's also relevant if a page happens to be laid out
* such that one half of its nodes are all "small" and
* the other half of its nodes are "large." If the new
* item is also "large" and falls on the half with
* "large" nodes, it also may not fit.
*
* As a final tweak, if the new item goes on the last
* spot on the page (and thus, onto the new page), bias
* the split so the new page is emptier than the old page.
* This yields better packing during sequential inserts.
*/
if (nkeys < 32 || nsize > pmax/16 || newindx >= nkeys) {
/* Find split point */
psize = 0;
if (newindx <= split_indx || newindx >= nkeys) {
i = 0; j = 1;
k = newindx >= nkeys ? nkeys : split_indx+1+IS_LEAF(mp);
} else {
i = nkeys; j = -1;
k = split_indx-1;
}
for (; i!=k; i+=j) {
if (i == newindx) {
psize += nsize;
node = NULL;
} else {
node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
if (IS_LEAF(mp)) {
if (F_ISSET(node->mn_flags, F_BIGDATA))
psize += sizeof(MDB_ovpage);
else
psize += NODEDSZ(node);
}
psize = EVEN(psize);
}
if (psize > pmax || i == k-j) {
split_indx = i + (j<0);
break;
}
}
}
if (split_indx == newindx) {
sepkey.mv_size = newkey->mv_size;
sepkey.mv_data = newkey->mv_data;
} else {
node = (MDB_node *)((char *)mp + copy->mp_ptrs[split_indx] + PAGEBASE);
sepkey.mv_size = node->mn_ksize;
sepkey.mv_data = NODEKEY(node);
}
}
}
DPRINTF(("separator is %d [%s]", split_indx, DKEY(&sepkey)));
/* Copy separator key to the parent.
*/
if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(env, &sepkey)) {
int snum = mc->mc_snum;
mn.mc_snum--;
mn.mc_top--;
did_split = 1;
/* We want other splits to find mn when doing fixups */
WITH_CURSOR_TRACKING(mn,
rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0));
if (rc)
goto done;
/* root split? */
if (mc->mc_snum > snum) {
ptop++;
}
/* Right page might now have changed parent.
* Check if left page also changed parent.
*/
if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
for (i=0; i<ptop; i++) {
mc->mc_pg[i] = mn.mc_pg[i];
mc->mc_ki[i] = mn.mc_ki[i];
}
mc->mc_pg[ptop] = mn.mc_pg[ptop];
if (mn.mc_ki[ptop]) {
mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
} else {
/* find right page's left sibling */
mc->mc_ki[ptop] = mn.mc_ki[ptop];
rc = mdb_cursor_sibling(mc, 0);
}
}
} else {
mn.mc_top--;
rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
mn.mc_top++;
}
if (rc != MDB_SUCCESS) {
if (rc == MDB_NOTFOUND) /* improper mdb_cursor_sibling() result */
rc = MDB_PROBLEM;
goto done;
}
if (nflags & MDB_APPEND) {
mc->mc_pg[mc->mc_top] = rp;
mc->mc_ki[mc->mc_top] = 0;
rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
if (rc)
goto done;
for (i=0; i<mc->mc_top; i++)
mc->mc_ki[i] = mn.mc_ki[i];
} else if (!IS_LEAF2(mp)) {
/* Move nodes */
mc->mc_pg[mc->mc_top] = rp;
i = split_indx;
j = 0;
do {
if (i == newindx) {
rkey.mv_data = newkey->mv_data;
rkey.mv_size = newkey->mv_size;
if (IS_LEAF(mp)) {
rdata = newdata;
} else
pgno = newpgno;
flags = nflags;
/* Update index for the new key. */
mc->mc_ki[mc->mc_top] = j;
} else {
node = (MDB_node *)((char *)mp + copy->mp_ptrs[i] + PAGEBASE);
rkey.mv_data = NODEKEY(node);
rkey.mv_size = node->mn_ksize;
if (IS_LEAF(mp)) {
xdata.mv_data = NODEDATA(node);
xdata.mv_size = NODEDSZ(node);
rdata = &xdata;
} else
pgno = NODEPGNO(node);
flags = node->mn_flags;
}
if (!IS_LEAF(mp) && j == 0) {
/* First branch index doesn't need key data. */
rkey.mv_size = 0;
}
rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
if (rc)
goto done;
if (i == nkeys) {
i = 0;
j = 0;
mc->mc_pg[mc->mc_top] = copy;
} else {
i++;
j++;
}
} while (i != split_indx);
nkeys = NUMKEYS(copy);
for (i=0; i<nkeys; i++)
mp->mp_ptrs[i] = copy->mp_ptrs[i];
mp->mp_lower = copy->mp_lower;
mp->mp_upper = copy->mp_upper;
memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
env->me_psize - copy->mp_upper - PAGEBASE);
/* reset back to original page */
if (newindx < split_indx) {
mc->mc_pg[mc->mc_top] = mp;
} else {
mc->mc_pg[mc->mc_top] = rp;
mc->mc_ki[ptop]++;
/* Make sure mc_ki is still valid.
*/
if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
for (i=0; i<=ptop; i++) {
mc->mc_pg[i] = mn.mc_pg[i];
mc->mc_ki[i] = mn.mc_ki[i];
}
}
}
if (nflags & MDB_RESERVE) {
node = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (!(node->mn_flags & F_BIGDATA))
newdata->mv_data = NODEDATA(node);
}
} else {
if (newindx >= split_indx) {
mc->mc_pg[mc->mc_top] = rp;
mc->mc_ki[ptop]++;
/* Make sure mc_ki is still valid.
*/
if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
for (i=0; i<=ptop; i++) {
mc->mc_pg[i] = mn.mc_pg[i];
mc->mc_ki[i] = mn.mc_ki[i];
}
}
}
}
{
/* Adjust other cursors pointing to mp */
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
nkeys = NUMKEYS(mp);
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == mc)
continue;
if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))
continue;
if (new_root) {
int k;
/* sub cursors may be on different DB */
if (m3->mc_pg[0] != mp)
continue;
/* root split */
for (k=new_root; k>=0; k--) {
m3->mc_ki[k+1] = m3->mc_ki[k];
m3->mc_pg[k+1] = m3->mc_pg[k];
}
if (m3->mc_ki[0] >= nkeys) {
m3->mc_ki[0] = 1;
} else {
m3->mc_ki[0] = 0;
}
m3->mc_pg[0] = mc->mc_pg[0];
m3->mc_snum++;
m3->mc_top++;
}
if (m3->mc_top >= mc->mc_top && m3->mc_pg[mc->mc_top] == mp) {
if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
m3->mc_ki[mc->mc_top]++;
if (m3->mc_ki[mc->mc_top] >= nkeys) {
m3->mc_pg[mc->mc_top] = rp;
m3->mc_ki[mc->mc_top] -= nkeys;
for (i=0; i<mc->mc_top; i++) {
m3->mc_ki[i] = mn.mc_ki[i];
m3->mc_pg[i] = mn.mc_pg[i];
}
}
} else if (!did_split && m3->mc_top >= ptop && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
m3->mc_ki[ptop]++;
}
if (IS_LEAF(mp))
XCURSOR_REFRESH(m3, mc->mc_top, m3->mc_pg[mc->mc_top]);
}
}
DPRINTF(("mp left: %d, rp left: %d", SIZELEFT(mp), SIZELEFT(rp)));
done:
if (copy) /* tmp page */
mdb_page_free(env, copy);
if (rc)
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
int
mdb_put(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data, unsigned int flags)
{
MDB_cursor mc;
MDB_xcursor mx;
int rc;
if (!key || !data || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
if (flags & ~(MDB_NOOVERWRITE|MDB_NODUPDATA|MDB_RESERVE|MDB_APPEND|MDB_APPENDDUP))
return EINVAL;
if (txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_BLOCKED))
return (txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
mdb_cursor_init(&mc, txn, dbi, &mx);
mc.mc_next = txn->mt_cursors[dbi];
txn->mt_cursors[dbi] = &mc;
rc = mdb_cursor_put(&mc, key, data, flags);
txn->mt_cursors[dbi] = mc.mc_next;
return rc;
}
#ifndef MDB_WBUF
#define MDB_WBUF (1024*1024)
#endif
#define MDB_EOF 0x10 /**< #mdb_env_copyfd1() is done reading */
/** State needed for a double-buffering compacting copy. */
typedef struct mdb_copy {
MDB_env *mc_env;
MDB_txn *mc_txn;
pthread_mutex_t mc_mutex;
pthread_cond_t mc_cond; /**< Condition variable for #mc_new */
char *mc_wbuf[2];
char *mc_over[2];
int mc_wlen[2];
int mc_olen[2];
pgno_t mc_next_pgno;
HANDLE mc_fd;
int mc_toggle; /**< Buffer number in provider */
int mc_new; /**< (0-2 buffers to write) | (#MDB_EOF at end) */
/** Error code. Never cleared if set. Both threads can set nonzero
* to fail the copy. Not mutex-protected, LMDB expects atomic int.
*/
volatile int mc_error;
} mdb_copy;
/** Dedicated writer thread for compacting copy. */
static THREAD_RET ESECT CALL_CONV
mdb_env_copythr(void *arg)
{
mdb_copy *my = arg;
char *ptr;
int toggle = 0, wsize, rc;
#ifdef _WIN32
DWORD len;
#define DO_WRITE(rc, fd, ptr, w2, len) rc = WriteFile(fd, ptr, w2, &len, NULL)
#else
int len;
#define DO_WRITE(rc, fd, ptr, w2, len) len = write(fd, ptr, w2); rc = (len >= 0)
#ifdef SIGPIPE
sigset_t set;
sigemptyset(&set);
sigaddset(&set, SIGPIPE);
if ((rc = pthread_sigmask(SIG_BLOCK, &set, NULL)) != 0)
my->mc_error = rc;
#endif
#endif
pthread_mutex_lock(&my->mc_mutex);
for(;;) {
while (!my->mc_new)
pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
if (my->mc_new == 0 + MDB_EOF) /* 0 buffers, just EOF */
break;
wsize = my->mc_wlen[toggle];
ptr = my->mc_wbuf[toggle];
again:
rc = MDB_SUCCESS;
while (wsize > 0 && !my->mc_error) {
DO_WRITE(rc, my->mc_fd, ptr, wsize, len);
if (!rc) {
rc = ErrCode();
#if defined(SIGPIPE) && !defined(_WIN32)
if (rc == EPIPE) {
/* Collect the pending SIGPIPE, otherwise at least OS X
* gives it to the process on thread-exit (ITS#8504).
*/
int tmp;
sigwait(&set, &tmp);
}
#endif
break;
} else if (len > 0) {
rc = MDB_SUCCESS;
ptr += len;
wsize -= len;
continue;
} else {
rc = EIO;
break;
}
}
if (rc) {
my->mc_error = rc;
}
/* If there's an overflow page tail, write it too */
if (my->mc_olen[toggle]) {
wsize = my->mc_olen[toggle];
ptr = my->mc_over[toggle];
my->mc_olen[toggle] = 0;
goto again;
}
my->mc_wlen[toggle] = 0;
toggle ^= 1;
/* Return the empty buffer to provider */
my->mc_new--;
pthread_cond_signal(&my->mc_cond);
}
pthread_mutex_unlock(&my->mc_mutex);
return (THREAD_RET)0;
#undef DO_WRITE
}
/** Give buffer and/or #MDB_EOF to writer thread, await unused buffer.
*
* @param[in] my control structure.
* @param[in] adjust (1 to hand off 1 buffer) | (MDB_EOF when ending).
*/
static int ESECT
mdb_env_cthr_toggle(mdb_copy *my, int adjust)
{
pthread_mutex_lock(&my->mc_mutex);
my->mc_new += adjust;
pthread_cond_signal(&my->mc_cond);
while (my->mc_new & 2) /* both buffers in use */
pthread_cond_wait(&my->mc_cond, &my->mc_mutex);
pthread_mutex_unlock(&my->mc_mutex);
my->mc_toggle ^= (adjust & 1);
/* Both threads reset mc_wlen, to be safe from threading errors */
my->mc_wlen[my->mc_toggle] = 0;
return my->mc_error;
}
/** Depth-first tree traversal for compacting copy.
* @param[in] my control structure.
* @param[in,out] pg database root.
* @param[in] flags includes #F_DUPDATA if it is a sorted-duplicate sub-DB.
*/
static int ESECT
mdb_env_cwalk(mdb_copy *my, pgno_t *pg, int flags)
{
MDB_cursor mc = {0};
MDB_node *ni;
MDB_page *mo, *mp, *leaf;
char *buf, *ptr;
int rc, toggle;
unsigned int i;
/* Empty DB, nothing to do */
if (*pg == P_INVALID)
return MDB_SUCCESS;
mc.mc_snum = 1;
mc.mc_txn = my->mc_txn;
mc.mc_flags = my->mc_txn->mt_flags & (C_ORIG_RDONLY|C_WRITEMAP);
rc = MDB_PAGE_GET(&mc, *pg, 1, &mc.mc_pg[0]);
if (rc)
return rc;
rc = mdb_page_search_root(&mc, NULL, MDB_PS_FIRST);
if (rc)
return rc;
/* Make cursor pages writable */
buf = ptr = malloc(my->mc_env->me_psize * mc.mc_snum);
if (buf == NULL)
return ENOMEM;
for (i=0; i<mc.mc_top; i++) {
mdb_page_copy((MDB_page *)ptr, mc.mc_pg[i], my->mc_env->me_psize);
mc.mc_pg[i] = (MDB_page *)ptr;
ptr += my->mc_env->me_psize;
}
/* This is writable space for a leaf page. Usually not needed. */
leaf = (MDB_page *)ptr;
toggle = my->mc_toggle;
while (mc.mc_snum > 0) {
unsigned n;
mp = mc.mc_pg[mc.mc_top];
n = NUMKEYS(mp);
if (IS_LEAF(mp)) {
if (!IS_LEAF2(mp) && !(flags & F_DUPDATA)) {
for (i=0; i<n; i++) {
ni = NODEPTR(mp, i);
if (ni->mn_flags & F_BIGDATA) {
MDB_page *omp;
MDB_ovpage ovp;
/* Need writable leaf */
if (mp != leaf) {
mc.mc_pg[mc.mc_top] = leaf;
mdb_page_copy(leaf, mp, my->mc_env->me_psize);
mp = leaf;
ni = NODEPTR(mp, i);
}
memcpy(&ovp, NODEDATA(ni), sizeof(ovp));
rc = MDB_PAGE_GET(&mc, ovp.op_pgno, ovp.op_pages, &omp);
if (rc)
goto done;
if (my->mc_wlen[toggle] >= MDB_WBUF) {
rc = mdb_env_cthr_toggle(my, 1);
if (rc)
goto done;
toggle = my->mc_toggle;
}
mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
memcpy(mo, omp, my->mc_env->me_psize);
ovp.op_pgno = my->mc_next_pgno;
ovp.op_txnid = 1;
memcpy(NODEDATA(ni), &ovp, sizeof(ovp));
my->mc_next_pgno += ovp.op_pages;
my->mc_wlen[toggle] += my->mc_env->me_psize;
if (ovp.op_pages > 1) {
my->mc_olen[toggle] = my->mc_env->me_psize * (ovp.op_pages - 1);
my->mc_over[toggle] = (char *)omp + my->mc_env->me_psize;
rc = mdb_env_cthr_toggle(my, 1);
if (rc)
goto done;
toggle = my->mc_toggle;
}
} else if (ni->mn_flags & F_SUBDATA) {
MDB_db db;
/* Need writable leaf */
if (mp != leaf) {
mc.mc_pg[mc.mc_top] = leaf;
mdb_page_copy(leaf, mp, my->mc_env->me_psize);
mp = leaf;
ni = NODEPTR(mp, i);
}
memcpy(&db, NODEDATA(ni), sizeof(db));
my->mc_toggle = toggle;
rc = mdb_env_cwalk(my, &db.md_root, ni->mn_flags & F_DUPDATA);
if (rc)
goto done;
toggle = my->mc_toggle;
memcpy(NODEDATA(ni), &db, sizeof(db));
}
}
}
} else {
mc.mc_ki[mc.mc_top]++;
if (mc.mc_ki[mc.mc_top] < n) {
pgno_t pg;
again:
ni = NODEPTR(mp, mc.mc_ki[mc.mc_top]);
pg = NODEPGNO(ni);
rc = MDB_PAGE_GET(&mc, pg, 1, &mp);
if (rc)
goto done;
mc.mc_top++;
mc.mc_snum++;
mc.mc_ki[mc.mc_top] = 0;
if (IS_BRANCH(mp)) {
/* Whenever we advance to a sibling branch page,
* we must proceed all the way down to its first leaf.
*/
mdb_page_copy(mc.mc_pg[mc.mc_top], mp, my->mc_env->me_psize);
goto again;
} else
mc.mc_pg[mc.mc_top] = mp;
continue;
}
}
if (my->mc_wlen[toggle] >= MDB_WBUF) {
rc = mdb_env_cthr_toggle(my, 1);
if (rc)
goto done;
toggle = my->mc_toggle;
}
mo = (MDB_page *)(my->mc_wbuf[toggle] + my->mc_wlen[toggle]);
mdb_page_copy(mo, mp, my->mc_env->me_psize);
mo->mp_pgno = my->mc_next_pgno++;
mo->mp_txnid = 1;
my->mc_wlen[toggle] += my->mc_env->me_psize;
if (mc.mc_top) {
/* Update parent if there is one */
ni = NODEPTR(mc.mc_pg[mc.mc_top-1], mc.mc_ki[mc.mc_top-1]);
SETPGNO(ni, mo->mp_pgno);
mdb_cursor_pop(&mc);
} else {
/* Otherwise we're done */
*pg = mo->mp_pgno;
break;
}
}
done:
free(buf);
return rc;
}
/** Copy environment with compaction. */
static int ESECT
mdb_env_copyfd1(MDB_env *env, HANDLE fd)
{
MDB_meta *mm;
MDB_page *mp;
mdb_copy my = {0};
MDB_txn *txn = NULL;
pthread_t thr;
pgno_t root, new_root;
int rc = MDB_SUCCESS;
#ifdef _WIN32
if (!(my.mc_mutex = CreateMutex(NULL, FALSE, NULL)) ||
!(my.mc_cond = CreateEvent(NULL, FALSE, FALSE, NULL))) {
rc = ErrCode();
goto done;
}
my.mc_wbuf[0] = _aligned_malloc(MDB_WBUF*2, env->me_os_psize);
if (my.mc_wbuf[0] == NULL) {
/* _aligned_malloc() sets errno, but we use Windows error codes */
rc = ERROR_NOT_ENOUGH_MEMORY;
goto done;
}
#else
if ((rc = pthread_mutex_init(&my.mc_mutex, NULL)) != 0)
return rc;
if ((rc = pthread_cond_init(&my.mc_cond, NULL)) != 0)
goto done2;
#ifdef HAVE_MEMALIGN
my.mc_wbuf[0] = memalign(env->me_os_psize, MDB_WBUF*2);
if (my.mc_wbuf[0] == NULL) {
rc = errno;
goto done;
}
#else
{
void *p;
if ((rc = posix_memalign(&p, env->me_os_psize, MDB_WBUF*2)) != 0)
goto done;
my.mc_wbuf[0] = p;
}
#endif
#endif
memset(my.mc_wbuf[0], 0, MDB_WBUF*2);
my.mc_wbuf[1] = my.mc_wbuf[0] + MDB_WBUF;
my.mc_next_pgno = NUM_METAS;
my.mc_env = env;
my.mc_fd = fd;
rc = THREAD_CREATE(thr, mdb_env_copythr, &my);
if (rc)
goto done;
rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
if (rc)
goto finish;
mp = (MDB_page *)my.mc_wbuf[0];
memset(mp, 0, NUM_METAS * env->me_psize);
mp->mp_pgno = 0;
mp->mp_flags = P_META;
mm = (MDB_meta *)METADATA(mp);
mdb_env_init_meta0(env, mm);
mm->mm_address = env->me_metas[0]->mm_address;
mp = (MDB_page *)(my.mc_wbuf[0] + env->me_psize);
mp->mp_pgno = 1;
mp->mp_flags = P_META;
*(MDB_meta *)METADATA(mp) = *mm;
mm = (MDB_meta *)METADATA(mp);
/* Set metapage 1 with current main DB */
root = new_root = txn->mt_dbs[MAIN_DBI].md_root;
if (root != P_INVALID) {
/* Count free pages + freeDB pages. Subtract from last_pg
* to find the new last_pg, which also becomes the new root.
*/
MDB_ID freecount = 0;
MDB_cursor mc;
MDB_val key, data;
mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
while ((rc = mdb_cursor_get(&mc, &key, &data, MDB_NEXT)) == 0)
freecount += *(MDB_ID *)data.mv_data;
if (rc != MDB_NOTFOUND)
goto finish;
freecount += txn->mt_dbs[FREE_DBI].md_branch_pages +
txn->mt_dbs[FREE_DBI].md_leaf_pages +
txn->mt_dbs[FREE_DBI].md_overflow_pages;
new_root = txn->mt_next_pgno - 1 - freecount;
mm->mm_last_pg = new_root;
mm->mm_dbs[MAIN_DBI] = txn->mt_dbs[MAIN_DBI];
mm->mm_dbs[MAIN_DBI].md_root = new_root;
} else {
/* When the DB is empty, handle it specially to
* fix any breakage like page leaks from ITS#8174.
*/
mm->mm_dbs[MAIN_DBI].md_flags = txn->mt_dbs[MAIN_DBI].md_flags;
}
if (root != P_INVALID || mm->mm_dbs[MAIN_DBI].md_flags) {
mm->mm_txnid = 1; /* use metapage 1 */
}
my.mc_wlen[0] = env->me_psize * NUM_METAS;
my.mc_txn = txn;
rc = mdb_env_cwalk(&my, &root, 0);
if (rc == MDB_SUCCESS && root != new_root) {
rc = MDB_INCOMPATIBLE; /* page leak or corrupt DB */
}
finish:
if (rc)
my.mc_error = rc;
mdb_env_cthr_toggle(&my, 1 | MDB_EOF);
rc = THREAD_FINISH(thr);
mdb_txn_abort(txn);
done:
#ifdef _WIN32
if (my.mc_wbuf[0]) _aligned_free(my.mc_wbuf[0]);
if (my.mc_cond) CloseHandle(my.mc_cond);
if (my.mc_mutex) CloseHandle(my.mc_mutex);
#else
free(my.mc_wbuf[0]);
pthread_cond_destroy(&my.mc_cond);
done2:
pthread_mutex_destroy(&my.mc_mutex);
#endif
return rc ? rc : my.mc_error;
}
/** Copy environment as-is. */
static int ESECT
mdb_env_copyfd0(MDB_env *env, HANDLE fd)
{
MDB_txn *txn = NULL;
mdb_mutexref_t wmutex = NULL;
int rc;
mdb_size_t wsize, w3;
char *ptr;
#ifdef _WIN32
DWORD len, w2;
#define DO_WRITE(rc, fd, ptr, w2, len) rc = WriteFile(fd, ptr, w2, &len, NULL)
#else
ssize_t len;
size_t w2;
#define DO_WRITE(rc, fd, ptr, w2, len) len = write(fd, ptr, w2); rc = (len >= 0)
#endif
/* Do the lock/unlock of the reader mutex before starting the
* write txn. Otherwise other read txns could block writers.
*/
rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
if (rc)
return rc;
if (env->me_txns) {
/* We must start the actual read txn after blocking writers */
mdb_txn_end(txn, MDB_END_RESET_TMP);
/* Temporarily block writers until we snapshot the meta pages */
wmutex = env->me_wmutex;
if (LOCK_MUTEX(rc, env, wmutex))
goto leave;
rc = mdb_txn_renew0(txn);
if (rc) {
UNLOCK_MUTEX(wmutex);
goto leave;
}
}
wsize = env->me_psize * NUM_METAS;
ptr = env->me_map;
w2 = wsize;
while (w2 > 0) {
DO_WRITE(rc, fd, ptr, w2, len);
if (!rc) {
rc = ErrCode();
break;
} else if (len > 0) {
rc = MDB_SUCCESS;
ptr += len;
w2 -= len;
continue;
} else {
/* Non-blocking or async handles are not supported */
rc = EIO;
break;
}
}
if (wmutex)
UNLOCK_MUTEX(wmutex);
if (rc)
goto leave;
w3 = txn->mt_next_pgno * env->me_psize;
{
mdb_size_t fsize = 0;
if ((rc = mdb_fsize(env->me_fd, &fsize)))
goto leave;
if (w3 > fsize)
w3 = fsize;
}
wsize = w3 - wsize;
while (wsize > 0) {
if (wsize > MAX_WRITE)
w2 = MAX_WRITE;
else
w2 = wsize;
DO_WRITE(rc, fd, ptr, w2, len);
if (!rc) {
rc = ErrCode();
break;
} else if (len > 0) {
rc = MDB_SUCCESS;
ptr += len;
wsize -= len;
continue;
} else {
rc = EIO;
break;
}
}
leave:
mdb_txn_abort(txn);
return rc;
}
int ESECT
mdb_env_copyfd2(MDB_env *env, HANDLE fd, unsigned int flags)
{
if (flags & MDB_CP_COMPACT)
return mdb_env_copyfd1(env, fd);
else
return mdb_env_copyfd0(env, fd);
}
int ESECT
mdb_env_copyfd(MDB_env *env, HANDLE fd)
{
return mdb_env_copyfd2(env, fd, 0);
}
int ESECT
mdb_env_copy2(MDB_env *env, const char *path, unsigned int flags)
{
int rc;
MDB_name fname;
HANDLE newfd = INVALID_HANDLE_VALUE;
rc = mdb_fname_init(path, env->me_flags | MDB_NOLOCK, &fname);
if (rc == MDB_SUCCESS) {
rc = mdb_fopen(env, &fname, MDB_O_COPY, 0666, &newfd);
mdb_fname_destroy(fname);
}
if (rc == MDB_SUCCESS) {
rc = mdb_env_copyfd2(env, newfd, flags);
if (close(newfd) < 0 && rc == MDB_SUCCESS)
rc = ErrCode();
}
return rc;
}
int ESECT
mdb_env_copy(MDB_env *env, const char *path)
{
return mdb_env_copy2(env, path, 0);
}
int ESECT
mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
{
if (flag & ~CHANGEABLE)
return EINVAL;
if (onoff)
env->me_flags |= flag;
else
env->me_flags &= ~flag;
return MDB_SUCCESS;
}
int ESECT
mdb_env_get_flags(MDB_env *env, unsigned int *arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_flags & EXPOSED;
return MDB_SUCCESS;
}
int ESECT
mdb_env_set_userctx(MDB_env *env, void *ctx)
{
if (!env)
return EINVAL;
env->me_userctx = ctx;
return MDB_SUCCESS;
}
void * ESECT
mdb_env_get_userctx(MDB_env *env)
{
return env ? env->me_userctx : NULL;
}
int ESECT
mdb_env_set_assert(MDB_env *env, MDB_assert_func *func)
{
if (!env)
return EINVAL;
#ifndef NDEBUG
env->me_assert_func = func;
#endif
return MDB_SUCCESS;
}
#if MDB_RPAGE_CACHE
int ESECT
mdb_env_set_encrypt(MDB_env *env, MDB_enc_func *func, const MDB_val *key, unsigned int size)
{
char *kdata;
if (!env || !func || !key)
return EINVAL;
if (env->me_flags & MDB_ENV_ACTIVE)
return EINVAL;
if (! (kdata = malloc(key[0].mv_size)))
return ENOMEM;
memcpy(kdata, key->mv_data, key->mv_size);
free(env->me_enckey.mv_data);
env->me_enckey.mv_data = kdata;
env->me_enckey.mv_size = key->mv_size;
env->me_encfunc = func;
if (size)
env->me_esumsize = size;
env->me_flags |= MDB_REMAP_CHUNKS | MDB_ENCRYPT;
return MDB_SUCCESS;
}
int ESECT
mdb_env_set_checksum(MDB_env *env, MDB_sum_func *func, unsigned int size)
{
if (!env || !func || !size)
return EINVAL;
if (env->me_flags & MDB_ENV_ACTIVE)
return EINVAL;
env->me_sumfunc = func;
env->me_sumsize = size;
return MDB_SUCCESS;
}
#endif
int ESECT
mdb_env_get_path(MDB_env *env, const char **arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_path;
return MDB_SUCCESS;
}
int ESECT
mdb_env_get_fd(MDB_env *env, mdb_filehandle_t *arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_fd;
return MDB_SUCCESS;
}
int ESECT
mdb_env_set_pagesize(MDB_env *env, int size)
{
if (!env || env->me_map)
return EINVAL;
if (size > MAX_PAGESIZE || size < 256)
return EINVAL;
if (size & (size-1))
return EINVAL;
env->me_os_psize = size;
return MDB_SUCCESS;
}
/** Common code for #mdb_stat() and #mdb_env_stat().
* @param[in] env the environment to operate in.
* @param[in] db the #MDB_db record containing the stats to return.
* @param[out] arg the address of an #MDB_stat structure to receive the stats.
* @return 0, this function always succeeds.
*/
static int ESECT
mdb_stat0(MDB_env *env, MDB_db *db, MDB_stat *arg)
{
arg->ms_psize = env->me_psize;
arg->ms_depth = db->md_depth;
arg->ms_branch_pages = db->md_branch_pages;
arg->ms_leaf_pages = db->md_leaf_pages;
arg->ms_overflow_pages = db->md_overflow_pages;
arg->ms_entries = db->md_entries;
return MDB_SUCCESS;
}
int ESECT
mdb_env_stat(MDB_env *env, MDB_stat *arg)
{
MDB_meta *meta;
if (env == NULL || arg == NULL)
return EINVAL;
meta = mdb_env_pick_meta(env);
return mdb_stat0(env, &meta->mm_dbs[MAIN_DBI], arg);
}
int ESECT
mdb_env_info(MDB_env *env, MDB_envinfo *arg)
{
MDB_meta *meta;
if (env == NULL || arg == NULL)
return EINVAL;
meta = mdb_env_pick_meta(env);
arg->me_mapaddr = meta->mm_address;
arg->me_last_pgno = meta->mm_last_pg;
arg->me_last_txnid = meta->mm_txnid;
arg->me_mapsize = env->me_mapsize;
arg->me_maxreaders = env->me_maxreaders;
arg->me_numreaders = env->me_txns ? env->me_txns->mti_numreaders : 0;
return MDB_SUCCESS;
}
/** Set the default comparison functions for a database.
* Called immediately after a database is opened to set the defaults.
* The user can then override them with #mdb_set_compare() or
* #mdb_set_dupsort().
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_dbi_open()
*/
static void
mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
{
uint16_t f = txn->mt_dbs[dbi].md_flags;
txn->mt_dbxs[dbi].md_cmp =
(f & MDB_REVERSEKEY) ? mdb_cmp_memnr :
(f & MDB_INTEGERKEY) ? mdb_cmp_cint : mdb_cmp_memn;
txn->mt_dbxs[dbi].md_dcmp =
!(f & MDB_DUPSORT) ? 0 :
((f & MDB_INTEGERDUP)
? ((f & MDB_DUPFIXED) ? mdb_cmp_int : mdb_cmp_cint)
: ((f & MDB_REVERSEDUP) ? mdb_cmp_memnr : mdb_cmp_memn));
}
int mdb_dbi_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
{
MDB_val key, data;
MDB_dbi i;
MDB_cursor mc;
MDB_db dummy;
int rc, dbflag, exact;
unsigned int unused = 0, seq;
char *namedup;
size_t size;
if (flags & ~VALID_FLAGS)
return EINVAL;
if (txn->mt_flags & MDB_TXN_BLOCKED)
return MDB_BAD_TXN;
/* main DB? */
if (!name) {
*dbi = MAIN_DBI;
if (flags & PERSISTENT_FLAGS) {
uint16_t f2 = flags & PERSISTENT_FLAGS;
/* make sure flag changes get committed */
if ((txn->mt_dbs[MAIN_DBI].md_flags | f2) != txn->mt_dbs[MAIN_DBI].md_flags) {
txn->mt_dbs[MAIN_DBI].md_flags |= f2;
txn->mt_flags |= MDB_TXN_DIRTY;
}
}
mdb_default_cmp(txn, MAIN_DBI);
return MDB_SUCCESS;
}
if (txn->mt_dbxs[MAIN_DBI].md_cmp == NULL) {
mdb_default_cmp(txn, MAIN_DBI);
}
/* Is the DB already open? */
size = strlen(name) + 1;
for (i=CORE_DBS; i<txn->mt_numdbs; i++) {
if (!txn->mt_dbxs[i].md_name.mv_size) {
/* Remember this free slot */
if (!unused) unused = i;
continue;
}
if (size == txn->mt_dbxs[i].md_name.mv_size &&
!strcmp(name, txn->mt_dbxs[i].md_name.mv_data)) {
*dbi = i;
return MDB_SUCCESS;
}
}
/* If no free slot and max hit, fail */
if (!unused && txn->mt_numdbs >= txn->mt_env->me_maxdbs)
return MDB_DBS_FULL;
/* Cannot mix named databases with some mainDB flags */
if (txn->mt_dbs[MAIN_DBI].md_flags & (MDB_DUPSORT|MDB_INTEGERKEY))
return (flags & MDB_CREATE) ? MDB_INCOMPATIBLE : MDB_NOTFOUND;
/* Find the DB info */
dbflag = DB_NEW|DB_VALID|DB_USRVALID;
exact = 0;
key.mv_size = size;
key.mv_data = (void *)name;
mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
rc = mdb_cursor_set(&mc, &key, &data, MDB_SET, &exact);
if (rc == MDB_SUCCESS) {
/* make sure this is actually a DB */
MDB_node *node = NODEPTR(mc.mc_pg[mc.mc_top], mc.mc_ki[mc.mc_top]);
if ((node->mn_flags & (F_DUPDATA|F_SUBDATA)) != F_SUBDATA)
return MDB_INCOMPATIBLE;
} else {
if (rc != MDB_NOTFOUND || !(flags & MDB_CREATE))
return rc;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
return EACCES;
}
/* Done here so we cannot fail after creating a new DB */
if ((namedup = strdup(name)) == NULL)
return ENOMEM;
if (rc) {
/* MDB_NOTFOUND and MDB_CREATE: Create new DB */
data.mv_size = sizeof(MDB_db);
data.mv_data = &dummy;
memset(&dummy, 0, sizeof(dummy));
dummy.md_root = P_INVALID;
dummy.md_flags = flags & PERSISTENT_FLAGS;
WITH_CURSOR_TRACKING(mc,
rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA));
dbflag |= DB_DIRTY;
}
if (rc) {
free(namedup);
} else {
/* Got info, register DBI in this txn */
unsigned int slot = unused ? unused : txn->mt_numdbs;
txn->mt_dbxs[slot].md_name.mv_data = namedup;
txn->mt_dbxs[slot].md_name.mv_size = size;
txn->mt_dbxs[slot].md_rel = NULL;
txn->mt_dbflags[slot] = dbflag;
/* txn-> and env-> are the same in read txns, use
* tmp variable to avoid undefined assignment
*/
seq = ++txn->mt_env->me_dbiseqs[slot];
txn->mt_dbiseqs[slot] = seq;
memcpy(&txn->mt_dbs[slot], data.mv_data, sizeof(MDB_db));
*dbi = slot;
mdb_default_cmp(txn, slot);
if (!unused) {
txn->mt_numdbs++;
}
}
return rc;
}
int ESECT
mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
{
if (!arg || !TXN_DBI_EXIST(txn, dbi, DB_VALID))
return EINVAL;
if (txn->mt_flags & MDB_TXN_BLOCKED)
return MDB_BAD_TXN;
if (txn->mt_dbflags[dbi] & DB_STALE) {
MDB_cursor mc;
MDB_xcursor mx;
/* Stale, must read the DB's root. cursor_init does it for us. */
mdb_cursor_init(&mc, txn, dbi, &mx);
}
return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
}
void mdb_dbi_close(MDB_env *env, MDB_dbi dbi)
{
char *ptr;
if (dbi < CORE_DBS || dbi >= env->me_maxdbs)
return;
ptr = env->me_dbxs[dbi].md_name.mv_data;
/* If there was no name, this was already closed */
if (ptr) {
env->me_dbxs[dbi].md_name.mv_data = NULL;
env->me_dbxs[dbi].md_name.mv_size = 0;
env->me_dbflags[dbi] = 0;
env->me_dbiseqs[dbi]++;
free(ptr);
}
}
int mdb_dbi_flags(MDB_txn *txn, MDB_dbi dbi, unsigned int *flags)
{
/* We could return the flags for the FREE_DBI too but what's the point? */
if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
*flags = txn->mt_dbs[dbi].md_flags & PERSISTENT_FLAGS;
return MDB_SUCCESS;
}
/** Add all the DB's pages to the free list.
* @param[in] mc Cursor on the DB to free.
* @param[in] subs non-Zero to check for sub-DBs in this DB.
* @return 0 on success, non-zero on failure.
*/
static int
mdb_drop0(MDB_cursor *mc, int subs)
{
int rc;
rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
if (rc == MDB_SUCCESS) {
MDB_txn *txn = mc->mc_txn;
MDB_node *ni;
MDB_cursor mx;
unsigned int i;
/* DUPSORT sub-DBs have no ovpages/DBs. Omit scanning leaves.
* This also avoids any P_LEAF2 pages, which have no nodes.
* Also if the DB doesn't have sub-DBs and has no overflow
* pages, omit scanning leaves.
*/
if ((mc->mc_flags & C_SUB) ||
(!subs && !mc->mc_db->md_overflow_pages))
mdb_cursor_pop(mc);
mdb_cursor_copy(mc, &mx);
if (MDB_REMAPPING(mc->mc_txn->mt_env->me_flags)) {
/* bump refcount for mx's pages */
for (i=0; i<mc->mc_snum; i++)
MDB_PAGE_GET(&mx, mc->mc_pg[i]->mp_pgno, 1, &mx.mc_pg[i]);
}
while (mc->mc_snum > 0) {
MDB_page *mp = mc->mc_pg[mc->mc_top];
unsigned n = NUMKEYS(mp);
if (IS_LEAF(mp)) {
for (i=0; i<n; i++) {
ni = NODEPTR(mp, i);
if (ni->mn_flags & F_BIGDATA) {
MDB_ovpage ovp;
memcpy(&ovp, NODEDATA(ni), sizeof(ovp));
rc = mdb_midl_append_range(&txn->mt_free_pgs,
ovp.op_pgno, ovp.op_pages);
if (rc)
goto done;
mc->mc_db->md_overflow_pages -= ovp.op_pages;
if (!mc->mc_db->md_overflow_pages && !subs)
break;
} else if (subs && (ni->mn_flags & F_SUBDATA)) {
mdb_xcursor_init1(mc, ni);
rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
if (rc)
goto done;
}
}
if (!subs && !mc->mc_db->md_overflow_pages)
goto pop;
} else {
if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)
goto done;
for (i=0; i<n; i++) {
pgno_t pg;
ni = NODEPTR(mp, i);
pg = NODEPGNO(ni);
/* free it */
mdb_midl_xappend(txn->mt_free_pgs, pg);
}
}
if (!mc->mc_top)
break;
mc->mc_ki[mc->mc_top] = i;
rc = mdb_cursor_sibling(mc, 1);
if (rc) {
if (rc != MDB_NOTFOUND)
goto done;
/* no more siblings, go back to beginning
* of previous level.
*/
pop:
mdb_cursor_pop(mc);
mc->mc_ki[0] = 0;
for (i=1; i<mc->mc_snum; i++) {
mc->mc_ki[i] = 0;
mc->mc_pg[i] = mx.mc_pg[i];
}
}
}
/* free it */
rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
done:
if (rc)
txn->mt_flags |= MDB_TXN_ERROR;
/* drop refcount for mx's pages */
MDB_CURSOR_UNREF(&mx, 0);
} else if (rc == MDB_NOTFOUND) {
rc = MDB_SUCCESS;
}
mc->mc_flags &= ~C_INITIALIZED;
return rc;
}
int mdb_drop(MDB_txn *txn, MDB_dbi dbi, int del)
{
MDB_cursor *mc, *m2;
int rc;
if ((unsigned)del > 1 || !TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY))
return EACCES;
if (TXN_DBI_CHANGED(txn, dbi))
return MDB_BAD_DBI;
rc = mdb_cursor_open(txn, dbi, &mc);
if (rc)
return rc;
rc = mdb_drop0(mc, mc->mc_db->md_flags & MDB_DUPSORT);
/* Invalidate the dropped DB's cursors */
for (m2 = txn->mt_cursors[dbi]; m2; m2 = m2->mc_next)
m2->mc_flags &= ~(C_INITIALIZED|C_EOF);
if (rc)
goto leave;
/* Can't delete the main DB */
if (del && dbi >= CORE_DBS) {
rc = mdb_del0(txn, MAIN_DBI, &mc->mc_dbx->md_name, NULL, F_SUBDATA);
if (!rc) {
txn->mt_dbflags[dbi] = DB_STALE;
mdb_dbi_close(txn->mt_env, dbi);
} else {
txn->mt_flags |= MDB_TXN_ERROR;
}
} else {
/* reset the DB record, mark it dirty */
txn->mt_dbflags[dbi] |= DB_DIRTY;
txn->mt_dbs[dbi].md_depth = 0;
txn->mt_dbs[dbi].md_branch_pages = 0;
txn->mt_dbs[dbi].md_leaf_pages = 0;
txn->mt_dbs[dbi].md_overflow_pages = 0;
txn->mt_dbs[dbi].md_entries = 0;
txn->mt_dbs[dbi].md_root = P_INVALID;
txn->mt_flags |= MDB_TXN_DIRTY;
}
leave:
mdb_cursor_close(mc);
return rc;
}
int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
{
if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
txn->mt_dbxs[dbi].md_cmp = cmp;
return MDB_SUCCESS;
}
int mdb_set_dupsort(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
{
if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
txn->mt_dbxs[dbi].md_dcmp = cmp;
return MDB_SUCCESS;
}
int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel)
{
if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
txn->mt_dbxs[dbi].md_rel = rel;
return MDB_SUCCESS;
}
int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx)
{
if (!TXN_DBI_EXIST(txn, dbi, DB_USRVALID))
return EINVAL;
txn->mt_dbxs[dbi].md_relctx = ctx;
return MDB_SUCCESS;
}
int ESECT
mdb_env_get_maxkeysize(MDB_env *env)
{
return ENV_MAXKEY(env);
}
int ESECT
mdb_reader_list(MDB_env *env, MDB_msg_func *func, void *ctx)
{
unsigned int i, rdrs;
MDB_reader *mr;
char buf[64];
int rc = 0, first = 1;
if (!env || !func)
return -1;
if (!env->me_txns) {
return func("(no reader locks)\n", ctx);
}
rdrs = env->me_txns->mti_numreaders;
mr = env->me_txns->mti_readers;
for (i=0; i<rdrs; i++) {
if (mr[i].mr_pid) {
txnid_t txnid = mr[i].mr_txnid;
sprintf(buf, txnid == (txnid_t)-1 ?
"%10d %"Z"x -\n" : "%10d %"Z"x %"Yu"\n",
(int)mr[i].mr_pid, (size_t)mr[i].mr_tid, txnid);
if (first) {
first = 0;
rc = func(" pid thread txnid\n", ctx);
if (rc < 0)
break;
}
rc = func(buf, ctx);
if (rc < 0)
break;
}
}
if (first) {
rc = func("(no active readers)\n", ctx);
}
return rc;
}
/** Insert pid into list if not already present.
* return -1 if already present.
*/
static int ESECT
mdb_pid_insert(MDB_PID_T *ids, MDB_PID_T pid)
{
/* binary search of pid in list */
unsigned base = 0;
unsigned cursor = 1;
int val = 0;
unsigned n = ids[0];
while( 0 < n ) {
unsigned pivot = n >> 1;
cursor = base + pivot + 1;
val = pid - ids[cursor];
if( val < 0 ) {
n = pivot;
} else if ( val > 0 ) {
base = cursor;
n -= pivot + 1;
} else {
/* found, so it's a duplicate */
return -1;
}
}
if( val > 0 ) {
++cursor;
}
ids[0]++;
for (n = ids[0]; n > cursor; n--)
ids[n] = ids[n-1];
ids[n] = pid;
return 0;
}
int ESECT
mdb_reader_check(MDB_env *env, int *dead)
{
if (!env)
return EINVAL;
if (dead)
*dead = 0;
return env->me_txns ? mdb_reader_check0(env, 0, dead) : MDB_SUCCESS;
}
/** As #mdb_reader_check(). \b rlocked is set if caller locked #me_rmutex. */
static int ESECT
mdb_reader_check0(MDB_env *env, int rlocked, int *dead)
{
mdb_mutexref_t rmutex = rlocked ? NULL : env->me_rmutex;
unsigned int i, j, rdrs;
MDB_reader *mr;
MDB_PID_T *pids, pid;
int rc = MDB_SUCCESS, count = 0;
rdrs = env->me_txns->mti_numreaders;
pids = malloc((rdrs+1) * sizeof(MDB_PID_T));
if (!pids)
return ENOMEM;
pids[0] = 0;
mr = env->me_txns->mti_readers;
for (i=0; i<rdrs; i++) {
pid = mr[i].mr_pid;
if (pid && pid != env->me_pid) {
if (mdb_pid_insert(pids, pid) == 0) {
if (!mdb_reader_pid(env, Pidcheck, pid)) {
/* Stale reader found */
j = i;
if (rmutex) {
if ((rc = LOCK_MUTEX0(rmutex)) != 0) {
if ((rc = mdb_mutex_failed(env, rmutex, rc)))
break;
rdrs = 0; /* the above checked all readers */
} else {
/* Recheck, a new process may have reused pid */
if (mdb_reader_pid(env, Pidcheck, pid))
j = rdrs;
}
}
for (; j<rdrs; j++)
if (mr[j].mr_pid == pid) {
DPRINTF(("clear stale reader pid %u txn %"Yd,
(unsigned) pid, mr[j].mr_txnid));
mr[j].mr_pid = 0;
count++;
}
if (rmutex)
UNLOCK_MUTEX(rmutex);
}
}
}
}
free(pids);
if (dead)
*dead = count;
return rc;
}
#ifdef MDB_ROBUST_SUPPORTED
/** Handle #LOCK_MUTEX0() failure.
* Try to repair the lock file if the mutex owner died.
* @param[in] env the environment handle
* @param[in] mutex LOCK_MUTEX0() mutex
* @param[in] rc LOCK_MUTEX0() error (nonzero)
* @return 0 on success with the mutex locked, or an error code on failure.
*/
static int ESECT
mdb_mutex_failed(MDB_env *env, mdb_mutexref_t mutex, int rc)
{
int rlocked, rc2;
MDB_meta *meta;
if (rc == MDB_OWNERDEAD) {
/* We own the mutex. Clean up after dead previous owner. */
rc = MDB_SUCCESS;
rlocked = (mutex == env->me_rmutex);
if (!rlocked) {
/* Keep mti_txnid updated, otherwise next writer can
* overwrite data which latest meta page refers to.
*/
meta = mdb_env_pick_meta(env);
env->me_txns->mti_txnid = meta->mm_txnid;
/* env is hosed if the dead thread was ours */
if (env->me_txn) {
env->me_flags |= MDB_FATAL_ERROR;
env->me_txn = NULL;
rc = MDB_PANIC;
}
}
DPRINTF(("%cmutex owner died, %s", (rlocked ? 'r' : 'w'),
(rc ? "this process' env is hosed" : "recovering")));
rc2 = mdb_reader_check0(env, rlocked, NULL);
if (rc2 == 0)
rc2 = mdb_mutex_consistent(mutex);
if (rc || (rc = rc2)) {
DPRINTF(("LOCK_MUTEX recovery failed, %s", mdb_strerror(rc)));
UNLOCK_MUTEX(mutex);
}
} else {
#ifdef _WIN32
rc = ErrCode();
#endif
DPRINTF(("LOCK_MUTEX failed, %s", mdb_strerror(rc)));
}
return rc;
}
#endif /* MDB_ROBUST_SUPPORTED */
#if defined(_WIN32)
/** Convert \b src to new wchar_t[] string with room for \b xtra extra chars */
static int ESECT
utf8_to_utf16(const char *src, MDB_name *dst, int xtra)
{
int rc, need = 0;
wchar_t *result = NULL;
for (;;) { /* malloc result, then fill it in */
need = MultiByteToWideChar(CP_UTF8, 0, src, -1, result, need);
if (!need) {
rc = ErrCode();
free(result);
return rc;
}
if (!result) {
result = malloc(sizeof(wchar_t) * (need + xtra));
if (!result)
return ENOMEM;
continue;
}
dst->mn_alloced = 1;
dst->mn_len = need - 1;
dst->mn_val = result;
return MDB_SUCCESS;
}
}
#endif /* defined(_WIN32) */
/** @} */