Read-only mirror of official repo on openldap.org. Issues and pull requests here are ignored. Use OpenLDAP ITS for issues.
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
lmdb/libraries/libmdb/mdb.c

4735 lines
126 KiB

/** @file mdb.c
* @brief memory-mapped database library
*
* A Btree-based database management library modeled loosely on the
* BerkeleyDB API, but much simplified.
*/
/*
* Copyright 2011 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.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <sys/uio.h>
#include <sys/mman.h>
#ifdef HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#include <fcntl.h>
#endif
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#ifndef _WIN32
#include <pthread.h>
#endif
#include "mdb.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 || ULONG_MAX % 0xFFFF
# error "Two's complement, reasonably sized integer types, please"
#endif
/** @defgroup internal MDB Internals
* @{
*/
/** @defgroup compat Windows 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.
* @{
*/
#ifdef _WIN32
#define pthread_t DWORD
#define pthread_mutex_t HANDLE
#define pthread_key_t DWORD
#define pthread_self() GetCurrentThreadId()
#define pthread_key_create(x,y) (*(x) = TlsAlloc())
#define pthread_key_delete(x) TlsFree(x)
#define pthread_getspecific(x) TlsGetValue(x)
#define pthread_setspecific(x,y) TlsSetValue(x,y)
#define pthread_mutex_unlock(x) ReleaseMutex(x)
#define pthread_mutex_lock(x) WaitForSingleObject(x, INFINITE)
#define LOCK_MUTEX_R(env) pthread_mutex_lock((env)->me_rmutex)
#define UNLOCK_MUTEX_R(env) pthread_mutex_unlock((env)->me_rmutex)
#define LOCK_MUTEX_W(env) pthread_mutex_lock((env)->me_wmutex)
#define UNLOCK_MUTEX_W(env) pthread_mutex_unlock((env)->me_wmutex)
#define getpid() GetCurrentProcessId()
#define fdatasync(fd) (!FlushFileBuffers(fd))
#define ErrCode() GetLastError()
#define GET_PAGESIZE(x) {SYSTEM_INFO si; GetSystemInfo(&si); (x) = si.dwPageSize;}
#define close(fd) CloseHandle(fd)
#define munmap(ptr,len) UnmapViewOfFile(ptr)
#else
/** Lock the reader mutex.
*/
#define LOCK_MUTEX_R(env) pthread_mutex_lock(&(env)->me_txns->mti_mutex)
/** Unlock the reader mutex.
*/
#define UNLOCK_MUTEX_R(env) pthread_mutex_unlock(&(env)->me_txns->mti_mutex)
/** Lock the writer mutex.
* Only a single write transaction is allowed at a time. Other writers
* will block waiting for this mutex.
*/
#define LOCK_MUTEX_W(env) pthread_mutex_lock(&(env)->me_txns->mti_wmutex)
/** Unlock the writer mutex.
*/
#define UNLOCK_MUTEX_W(env) pthread_mutex_unlock(&(env)->me_txns->mti_wmutex)
/** 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
/** @} */
#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.
* Otherwise compile with the less efficient -DMDB_DSYNC=O_SYNC.
*/
#ifndef MDB_DSYNC
# define MDB_DSYNC O_DSYNC
#endif
#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 ID pgno_t;
/** A transaction ID.
* See struct MDB_txn.mt_txnid for details.
*/
typedef ID txnid_t;
/** @defgroup debug Debug Macros
* @{
*/
#ifndef DEBUG
/** Enable debug output.
* 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 DEBUG 0
#endif
#if !(__STDC_VERSION__ >= 199901L || defined(__GNUC__))
# define DPRINTF (void) /* Vararg macros may be unsupported */
#elif DEBUG
/** Print a debug message with printf formatting. */
# define DPRINTF(fmt, ...) /**< Requires 2 or more args */ \
fprintf(stderr, "%s:%d " fmt "\n", __func__, __LINE__, __VA_ARGS__)
#else
# define DPRINTF(fmt, ...) ((void) 0)
#endif
/** Print a debug string.
* The string is printed literally, with no format processing.
*/
#define DPUTS(arg) DPRINTF("%s", arg)
/** @} */
/** A default memory page size.
* The actual size is platform-dependent, but we use this for
* boot-strapping. We probably should not be using this any more.
* The #GET_PAGESIZE() macro is used to get the actual size.
*
* 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 PAGESIZE 4096
/** 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 MDB 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 file format. */
#define MDB_VERSION 1
/** The maximum size of a key in the database.
* While data items have essentially unbounded size, we require that
* keys all fit onto a regular page. This limit could be raised a bit
* further if needed; to something just under #PAGESIZE / #MDB_MINKEYS.
*/
#define MAXKEYSIZE 511
#if DEBUG
/** A key buffer.
* @ingroup debug
* This is used for printing a hex dump of a key's contents.
*/
#define DKBUF char kbuf[(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 typedef int dummy_kbuf /* so we can put ';' after */
#define DKEY(x)
#endif
/** @defgroup lazylock Lazy Locking
* Macros for locks that are't actually needed.
* The DB view is always consistent because all writes are wrapped in
* the wmutex. Finer-grained locks aren't necessary.
* @{
*/
#ifndef LAZY_LOCKS
/** Use lazy locking. I.e., don't lock these accesses at all. */
#define LAZY_LOCKS 1
#endif
#if LAZY_LOCKS
/** Grab the reader lock */
#define LAZY_MUTEX_LOCK(x)
/** Release the reader lock */
#define LAZY_MUTEX_UNLOCK(x)
/** Release the DB table reader/writer lock */
#define LAZY_RWLOCK_UNLOCK(x)
/** Grab the DB table write lock */
#define LAZY_RWLOCK_WRLOCK(x)
/** Grab the DB table read lock */
#define LAZY_RWLOCK_RDLOCK(x)
/** Declare the DB table rwlock. Should not be followed by ';'. */
#define LAZY_RWLOCK_DEF(x)
/** Initialize the DB table rwlock */
#define LAZY_RWLOCK_INIT(x,y)
/** Destroy the DB table rwlock */
#define LAZY_RWLOCK_DESTROY(x)
#else
#define LAZY_MUTEX_LOCK(x) pthread_mutex_lock(x)
#define LAZY_MUTEX_UNLOCK(x) pthread_mutex_unlock(x)
#define LAZY_RWLOCK_UNLOCK(x) pthread_rwlock_unlock(x)
#define LAZY_RWLOCK_WRLOCK(x) pthread_rwlock_wrlock(x)
#define LAZY_RWLOCK_RDLOCK(x) pthread_rwlock_rdlock(x)
#define LAZY_RWLOCK_DEF(x) pthread_rwlock_t x;
#define LAZY_RWLOCK_INIT(x,y) pthread_rwlock_init(x,y)
#define LAZY_RWLOCK_DESTROY(x) pthread_rwlock_destroy(x)
#endif
/** @} */
/** An invalid page number.
* Mainly used to denote an empty tree.
*/
#define P_INVALID (~0UL)
/** Test if a flag \b f is set in a flag word \b w. */
#define F_ISSET(w, f) (((w) & (f)) == (f))
/** 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;
/** 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.
*
* 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.
*
* @todo We don't actually do such coalescing yet, we grab pages from one
* old transaction at a time.
* @{
*/
/** 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 {
/** The current Transaction ID when this transaction began.
* 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.
*/
txnid_t mrb_txnid;
/** The process ID of the process owning this reader txn. */
pid_t mrb_pid;
/** The thread ID of the thread owning this txn. */
pthread_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 will also be used on
* MacOSX/Darwin (using named semaphores) since MacOSX doesn't support
* process-shared POSIX mutexes.
*/
typedef struct MDB_txbody {
/** Stamp identifying this as an MDB lock file. It must be set
* to #MDB_MAGIC. */
uint32_t mtb_magic;
/** Version number of this lock file. Must be set to #MDB_VERSION. */
uint32_t mtb_version;
#ifdef _WIN32
char mtb_rmname[32];
#else
/** Mutex protecting access to this table.
* This is the reader lock that #LOCK_MUTEX_R acquires.
*/
pthread_mutex_t mtb_mutex;
#endif
/** 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.
*/
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.
*/
unsigned mtb_numreaders;
/** The ID of the most recent meta page in the database.
* This is recorded here only for convenience; the value can always
* be determined by reading the main database meta pages.
*/
uint32_t mtb_me_toggle;
} MDB_txbody;
/** The actual reader table definition. */
typedef struct MDB_txninfo {
union {
MDB_txbody mtb;
#define mti_magic mt1.mtb.mtb_magic
#define mti_version mt1.mtb.mtb_version
#define mti_mutex mt1.mtb.mtb_mutex
#define mti_rmname mt1.mtb.mtb_rmname
#define mti_txnid mt1.mtb.mtb_txnid
#define mti_numreaders mt1.mtb.mtb_numreaders
#define mti_me_toggle mt1.mtb.mtb_me_toggle
char pad[(sizeof(MDB_txbody)+CACHELINE-1) & ~(CACHELINE-1)];
} mt1;
union {
#ifdef _WIN32
char mt2_wmname[32];
#define mti_wmname mt2.mt2_wmname
#else
pthread_mutex_t mt2_wmutex;
#define mti_wmutex mt2.mt2_wmutex
#endif
char pad[(sizeof(pthread_mutex_t)+CACHELINE-1) & ~(CACHELINE-1)];
} mt2;
MDB_reader mti_readers[1];
} MDB_txninfo;
/** @} */
/** Common header for all page types.
* Overflow pages occupy a number of contiguous pages with no
* headers on any page after the first.
*/
typedef struct MDB_page {
#define mp_pgno mp_p.p_pgno
#define mp_next mp_p.p_next
union padded {
pgno_t p_pgno; /**< page number */
void * p_next; /**< for in-memory list of freed structs */
} mp_p;
#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_DIRTY 0x10 /**< dirty page */
#define P_LEAF2 0x20 /**< for #MDB_DUPFIXED records */
uint32_t mp_flags;
#define mp_lower mp_pb.pb.pb_lower
#define mp_upper mp_pb.pb.pb_upper
#define mp_pages mp_pb.pb_pages
union page_bounds {
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 */
} mp_pb;
indx_t mp_ptrs[1]; /**< dynamic size */
} MDB_page;
/** Size of the page header, excluding dynamic data at the end */
#define PAGEHDRSZ ((unsigned) offsetof(MDB_page, mp_ptrs))
/** Address of first usable data byte in a page, after the header */
#define METADATA(p) ((void *)((char *)(p) + PAGEHDRSZ))
/** Number of nodes on a page */
#define NUMKEYS(p) (((p)->mp_lower - PAGEHDRSZ) >> 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)
/** The number of overflow pages needed to store the given size. */
#define OVPAGES(size, psize) ((PAGEHDRSZ-1 + (size)) / (psize) + 1)
/** Header for a single key/data pair within a page.
* We guarantee 2-byte alignment for nodes.
*/
typedef struct MDB_node {
/** lo and hi are used for data size on leaf nodes and for
* child pgno on branch nodes. On 64 bit platforms, flags
* is also used for pgno. (Branch nodes have no flags).
* They are in in host byte order in case that lets some
* accesses be optimized into a 32-bit word access.
*/
#define mn_lo mn_offset[__BYTE_ORDER!=__LITTLE_ENDIAN]
#define mn_hi mn_offset[__BYTE_ORDER==__LITTLE_ENDIAN] /**< part of dsize or pgno */
unsigned short mn_offset[2];
unsigned short mn_flags; /**< flags for special node types */
#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 */
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]))
/** 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)
/** 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 key, if requested. */
#define MDB_SET_KEY(node, key) { if ((key) != NULL) { \
(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_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 */
size_t md_entries; /**< number of data items */
pgno_t md_root; /**< the root page of this tree */
} MDB_db;
/** Handle for the DB used to track free pages. */
#define FREE_DBI 0
/** Handle for the default DB. */
#define MAIN_DBI 1
/** Identify a data item as a valid sub-DB record */
#define MDB_SUBDATA 0x8200
/** Meta page content. */
typedef struct MDB_meta {
/** Stamp identifying this as an MDB data file. It must be set
* to #MDB_MAGIC. */
uint32_t mm_magic;
/** Version number of this lock file. Must be set to #MDB_VERSION. */
uint32_t mm_version;
void *mm_address; /**< address for fixed mapping */
size_t mm_mapsize; /**< size of mmap region */
MDB_db mm_dbs[2]; /**< first is free space, 2nd is main db */
/** The size of pages used in this DB */
#define mm_psize mm_dbs[0].md_pad
/** Any persistent environment flags. @ref mdb_env */
#define mm_flags mm_dbs[0].md_flags
pgno_t mm_last_pg; /**< last used page in file */
txnid_t mm_txnid; /**< txnid that committed this page */
} MDB_meta;
/** Auxiliary DB info.
* The information here is mostly static/read-only. There is
* only a single copy of this record in the environment.
* The \b md_dirty flag is not read-only, but only a write
* transaction can ever update it, and only write transactions
* need to worry about it.
*/
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_dbi md_parent; /**< parent DB of a sub-DB */
unsigned int md_dirty; /**< TRUE if DB was written in this txn */
} MDB_dbx;
/** A database transaction.
* Every operation requires a transaction handle.
*/
struct MDB_txn {
pgno_t mt_next_pgno; /**< next unallocated page */
/** 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;
MDB_env *mt_env; /**< the DB environment */
/** The list of pages that became unused during this transaction.
* This is an #IDL.
*/
pgno_t *mt_free_pgs;
union {
ID2L dirty_list; /**< modified pages */
MDB_reader *reader; /**< this thread's slot in the reader table */
} mt_u;
/** 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;
/** Number of DB records in use. This number only ever increments;
* we don't decrement it when individual DB handles are closed.
*/
MDB_dbi mt_numdbs;
#define MDB_TXN_RDONLY 0x01 /**< read-only transaction */
#define MDB_TXN_ERROR 0x02 /**< an error has occurred */
unsigned int mt_flags;
/** Tracks which of the two meta pages was used at the start
* of this transaction.
*/
unsigned int mt_toggle;
};
/** 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 */
struct MDB_cursor {
/** 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;
unsigned short mc_snum; /**< number of pushed pages */
unsigned short mc_top; /**< index of top page, mc_snum-1 */
unsigned int mc_flags;
#define C_INITIALIZED 0x01 /**< cursor has been initialized and is valid */
#define C_EOF 0x02 /**< No more data */
#define C_XDIRTY 0x04 /**< @deprecated mc_xcursor needs to be flushed */
MDB_page *mc_pg[CURSOR_STACK]; /**< stack of pushed pages */
indx_t mc_ki[CURSOR_STACK]; /**< stack of page indices */
};
/** 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;
} MDB_xcursor;
/** A set of pages freed by an earlier transaction. */
typedef struct MDB_oldpages {
/** Usually we only read one record from the FREEDB at a time, but
* in case we read more, this will chain them together.
*/
struct MDB_oldpages *mo_next;
/** The ID of the transaction in which these pages were freed. */
txnid_t mo_txnid;
/** An #IDL of the pages */
pgno_t mo_pages[1]; /* dynamic */
} MDB_oldpages;
/** The database environment. */
struct MDB_env {
HANDLE me_fd; /**< The main data file */
HANDLE me_lfd; /**< The lock file */
HANDLE me_mfd; /**< just for writing the meta pages */
/** Failed to update the meta page. Probably an I/O error. */
#define MDB_FATAL_ERROR 0x80000000U
uint32_t me_flags;
uint32_t me_extrapad; /**< unused for now */
unsigned int me_maxreaders; /**< size of the reader table */
MDB_dbi me_numdbs; /**< number of DBs opened */
MDB_dbi me_maxdbs; /**< size of the DB table */
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 */
MDB_meta *me_metas[2]; /**< pointers to the two meta pages */
MDB_txn *me_txn; /**< current write transaction */
size_t me_mapsize; /**< size of the data memory map */
off_t me_size; /**< current file size */
pgno_t me_maxpg; /**< me_mapsize / me_psize */
unsigned int me_psize; /**< size of a page, from #GET_PAGESIZE */
unsigned int me_db_toggle; /**< which DB table is current */
MDB_dbx *me_dbxs; /**< array of static DB info */
MDB_db *me_dbs[2]; /**< two arrays of MDB_db info */
MDB_oldpages *me_pghead; /**< list of old page records */
pthread_key_t me_txkey; /**< thread-key for readers */
MDB_page *me_dpages; /**< list of malloc'd blocks for re-use */
/** IDL of pages that became unused in a write txn */
pgno_t me_free_pgs[MDB_IDL_UM_SIZE];
/** ID2L of pages that were written during a write txn */
ID2 me_dirty_list[MDB_IDL_UM_SIZE];
/** rwlock for the DB tables, if #LAZY_LOCKS is false */
LAZY_RWLOCK_DEF(me_dblock)
#ifdef _WIN32
HANDLE me_rmutex; /* Windows mutexes don't reside in shared mem */
HANDLE me_wmutex;
#endif
};
/** max number of pages to commit in one writev() call */
#define MDB_COMMIT_PAGES 64
static MDB_page *mdb_alloc_page(MDB_cursor *mc, int num);
static int mdb_touch(MDB_cursor *mc);
static int mdb_search_page_root(MDB_cursor *mc,
MDB_val *key, int modify);
static int mdb_search_page(MDB_cursor *mc,
MDB_val *key, int modify);
static int mdb_env_read_header(MDB_env *env, MDB_meta *meta);
static int mdb_env_read_meta(MDB_env *env, int *which);
static int mdb_env_write_meta(MDB_txn *txn);
static int mdb_get_page(MDB_txn *txn, pgno_t pgno, MDB_page **mp);
static MDB_node *mdb_search_node(MDB_cursor *mc, MDB_val *key, int *exactp);
static int mdb_add_node(MDB_cursor *mc, indx_t indx,
MDB_val *key, MDB_val *data, pgno_t pgno, uint8_t flags);
static void mdb_del_node(MDB_page *mp, indx_t indx, int ksize);
static int mdb_del0(MDB_cursor *mc, MDB_node *leaf);
static int mdb_read_data(MDB_txn *txn, MDB_node *leaf, MDB_val *data);
static int mdb_rebalance(MDB_cursor *mc);
static int mdb_update_key(MDB_page *mp, indx_t indx, MDB_val *key);
static int mdb_move_node(MDB_cursor *csrc, MDB_cursor *cdst);
static int mdb_merge(MDB_cursor *csrc, MDB_cursor *cdst);
static int mdb_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata,
pgno_t newpgno);
static MDB_page *mdb_new_page(MDB_cursor *mc, uint32_t flags, int num);
static void cursor_pop_page(MDB_cursor *mc);
static int cursor_push_page(MDB_cursor *mc, MDB_page *mp);
static int mdb_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 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 void mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi);
/** @cond */
static MDB_cmp_func memncmp, memnrcmp, intcmp, cintcmp;
/** @endcond */
#ifdef _WIN32
static SECURITY_DESCRIPTOR mdb_null_sd;
static SECURITY_ATTRIBUTES mdb_all_sa;
static int mdb_sec_inited;
#endif
/** Return the library version info. */
char *
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 MDB @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",
"MDB_VERSION_MISMATCH: Database environment version mismatch"
};
char *
mdb_strerror(int err)
{
if (!err)
return ("Successful return: 0");
if (err >= MDB_KEYEXIST && err <= MDB_VERSION_MISMATCH)
return mdb_errstr[err - MDB_KEYEXIST];
return strerror(err);
}
#if DEBUG
/** 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->mv_size > MAXKEYSIZE)
return "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
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;
}
#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)
{
if (txn->mt_dbxs[dbi].md_dcmp)
return txn->mt_dbxs[dbi].md_dcmp(a, b);
else
return EINVAL; /* too bad you can't distinguish this from a valid result */
}
/** Allocate pages for writing.
* If there are free pages available from older transactions, they
* will be re-used first. Otherwise a new page will be allocated.
* @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.
* @return Address of the allocated page(s). Requests for multiple pages
* will always be satisfied by a single contiguous chunk of memory.
*/
static MDB_page *
mdb_alloc_page(MDB_cursor *mc, int num)
{
MDB_txn *txn = mc->mc_txn;
MDB_page *np;
pgno_t pgno = P_INVALID;
ID2 mid;
if (txn->mt_txnid > 2) {
if (!txn->mt_env->me_pghead && mc->mc_dbi != FREE_DBI &&
txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
/* See if there's anything in the free DB */
MDB_cursor m2;
MDB_node *leaf;
txnid_t *kptr, oldest;
mdb_cursor_init(&m2, txn, FREE_DBI, NULL);
mdb_search_page(&m2, NULL, 0);
leaf = NODEPTR(m2.mc_pg[m2.mc_top], 0);
kptr = (txnid_t *)NODEKEY(leaf);
{
unsigned int i;
oldest = txn->mt_txnid - 1;
for (i=0; i<txn->mt_env->me_txns->mti_numreaders; i++) {
txnid_t mr = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
if (mr && mr < oldest)
oldest = mr;
}
}
if (oldest > *kptr) {
/* It's usable, grab it.
*/
MDB_oldpages *mop;
MDB_val data;
pgno_t *idl;
mdb_read_data(txn, leaf, &data);
idl = (ID *) data.mv_data;
mop = malloc(sizeof(MDB_oldpages) + MDB_IDL_SIZEOF(idl) - sizeof(pgno_t));
mop->mo_next = txn->mt_env->me_pghead;
mop->mo_txnid = *kptr;
txn->mt_env->me_pghead = mop;
memcpy(mop->mo_pages, idl, MDB_IDL_SIZEOF(idl));
#if DEBUG > 1
{
unsigned int i;
DPRINTF("IDL read txn %zu root %zu num %zu",
mop->mo_txnid, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
for (i=0; i<idl[0]; i++) {
DPRINTF("IDL %zu", idl[i+1]);
}
}
#endif
/* drop this IDL from the DB */
m2.mc_ki[m2.mc_top] = 0;
m2.mc_flags = C_INITIALIZED;
mdb_cursor_del(&m2, 0);
}
}
if (txn->mt_env->me_pghead) {
MDB_oldpages *mop = txn->mt_env->me_pghead;
if (num > 1) {
/* FIXME: For now, always use fresh pages. We
* really ought to search the free list for a
* contiguous range.
*/
;
} else {
/* peel pages off tail, so we only have to truncate the list */
pgno = MDB_IDL_LAST(mop->mo_pages);
if (MDB_IDL_IS_RANGE(mop->mo_pages)) {
mop->mo_pages[2]++;
if (mop->mo_pages[2] > mop->mo_pages[1])
mop->mo_pages[0] = 0;
} else {
mop->mo_pages[0]--;
}
if (MDB_IDL_IS_ZERO(mop->mo_pages)) {
txn->mt_env->me_pghead = mop->mo_next;
free(mop);
}
}
}
}
if (pgno == P_INVALID) {
/* DB size is maxed out */
if (txn->mt_next_pgno + num >= txn->mt_env->me_maxpg) {
assert(txn->mt_next_pgno + num < txn->mt_env->me_maxpg);
return NULL;
}
}
if (txn->mt_env->me_dpages && num == 1) {
np = txn->mt_env->me_dpages;
txn->mt_env->me_dpages = np->mp_next;
} else {
if ((np = malloc(txn->mt_env->me_psize * num )) == NULL)
return NULL;
}
if (pgno == P_INVALID) {
np->mp_pgno = txn->mt_next_pgno;
txn->mt_next_pgno += num;
} else {
np->mp_pgno = pgno;
}
mid.mid = np->mp_pgno;
mid.mptr = np;
mdb_mid2l_insert(txn->mt_u.dirty_list, &mid);
return np;
}
/** Touch a page: make it dirty and re-insert into tree with updated pgno.
* @param[in] mc cursor pointing to the page to be touched
* @return 0 on success, non-zero on failure.
*/
static int
mdb_touch(MDB_cursor *mc)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
pgno_t pgno;
if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
MDB_page *np;
if ((np = mdb_alloc_page(mc, 1)) == NULL)
return ENOMEM;
DPRINTF("touched db %u page %zu -> %zu", mc->mc_dbi, mp->mp_pgno, np->mp_pgno);
assert(mp->mp_pgno != np->mp_pgno);
mdb_midl_append(mc->mc_txn->mt_free_pgs, mp->mp_pgno);
pgno = np->mp_pgno;
memcpy(np, mp, mc->mc_txn->mt_env->me_psize);
mp = np;
mp->mp_pgno = pgno;
mp->mp_flags |= P_DIRTY;
mc->mc_pg[mc->mc_top] = mp;
/** If this page has a parent, update the parent to point to
* this new page.
*/
if (mc->mc_top)
SETPGNO(NODEPTR(mc->mc_pg[mc->mc_top-1], mc->mc_ki[mc->mc_top-1]), mp->mp_pgno);
}
return 0;
}
int
mdb_env_sync(MDB_env *env, int force)
{
int rc = 0;
if (force || !F_ISSET(env->me_flags, MDB_NOSYNC)) {
if (fdatasync(env->me_fd))
rc = ErrCode();
}
return rc;
}
static inline void
mdb_txn_reset0(MDB_txn *txn);
/** 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. This can only
* fail for read-only transactions, and then only if the
* reader table is full.
*/
static inline int
mdb_txn_renew0(MDB_txn *txn)
{
MDB_env *env = txn->mt_env;
if (txn->mt_flags & MDB_TXN_RDONLY) {
MDB_reader *r = pthread_getspecific(env->me_txkey);
if (!r) {
unsigned int i;
pid_t pid = getpid();
pthread_t tid = pthread_self();
LOCK_MUTEX_R(env);
for (i=0; i<env->me_txns->mti_numreaders; i++)
if (env->me_txns->mti_readers[i].mr_pid == 0)
break;
if (i == env->me_maxreaders) {
UNLOCK_MUTEX_R(env);
return ENOMEM;
}
env->me_txns->mti_readers[i].mr_pid = pid;
env->me_txns->mti_readers[i].mr_tid = tid;
if (i >= env->me_txns->mti_numreaders)
env->me_txns->mti_numreaders = i+1;
UNLOCK_MUTEX_R(env);
r = &env->me_txns->mti_readers[i];
pthread_setspecific(env->me_txkey, r);
}
txn->mt_txnid = env->me_txns->mti_txnid;
txn->mt_toggle = env->me_txns->mti_me_toggle;
r->mr_txnid = txn->mt_txnid;
txn->mt_u.reader = r;
} else {
LOCK_MUTEX_W(env);
txn->mt_txnid = env->me_txns->mti_txnid+1;
txn->mt_toggle = env->me_txns->mti_me_toggle;
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_next_pgno = env->me_metas[txn->mt_toggle]->mm_last_pg+1;
env->me_txn = txn;
}
/* Copy the DB arrays */
LAZY_RWLOCK_RDLOCK(&env->me_dblock);
txn->mt_numdbs = env->me_numdbs;
txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
memcpy(txn->mt_dbs, env->me_metas[txn->mt_toggle]->mm_dbs, 2 * sizeof(MDB_db));
if (txn->mt_numdbs > 2)
memcpy(txn->mt_dbs+2, env->me_dbs[env->me_db_toggle]+2,
(txn->mt_numdbs - 2) * sizeof(MDB_db));
LAZY_RWLOCK_UNLOCK(&env->me_dblock);
return MDB_SUCCESS;
}
int
mdb_txn_renew(MDB_txn *txn)
{
int rc;
if (!txn)
return EINVAL;
if (txn->mt_env->me_flags & MDB_FATAL_ERROR) {
DPUTS("environment had fatal error, must shutdown!");
return MDB_PANIC;
}
rc = mdb_txn_renew0(txn);
if (rc == MDB_SUCCESS) {
DPRINTF("renew txn %zu%c %p on mdbenv %p, root page %zu",
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;
}
int
mdb_txn_begin(MDB_env *env, unsigned int flags, MDB_txn **ret)
{
MDB_txn *txn;
int rc;
if (env->me_flags & MDB_FATAL_ERROR) {
DPUTS("environment had fatal error, must shutdown!");
return MDB_PANIC;
}
if ((txn = calloc(1, sizeof(MDB_txn) + env->me_maxdbs * sizeof(MDB_db))) == NULL) {
DPRINTF("calloc: %s", strerror(ErrCode()));
return ENOMEM;
}
txn->mt_dbs = (MDB_db *)(txn+1);
if (flags & MDB_RDONLY) {
txn->mt_flags |= MDB_TXN_RDONLY;
}
txn->mt_env = env;
rc = mdb_txn_renew0(txn);
if (rc)
free(txn);
else {
*ret = txn;
DPRINTF("begin txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) txn, (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
}
return rc;
}
/** Common code for #mdb_txn_reset() and #mdb_txn_abort().
* @param[in] txn the transaction handle to reset
*/
static inline void
mdb_txn_reset0(MDB_txn *txn)
{
MDB_env *env = txn->mt_env;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
txn->mt_u.reader->mr_txnid = 0;
} else {
MDB_oldpages *mop;
MDB_page *dp;
MDB_dbi dbi;
unsigned int i;
/* return all dirty pages to dpage list */
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
dp->mp_next = txn->mt_env->me_dpages;
txn->mt_env->me_dpages = dp;
} else {
/* large pages just get freed directly */
free(dp);
}
}
while ((mop = txn->mt_env->me_pghead)) {
txn->mt_env->me_pghead = mop->mo_next;
free(mop);
}
env->me_txn = NULL;
for (dbi=2; dbi<env->me_numdbs; dbi++)
env->me_dbxs[dbi].md_dirty = 0;
/* The writer mutex was locked in mdb_txn_begin. */
UNLOCK_MUTEX_W(env);
}
}
void
mdb_txn_reset(MDB_txn *txn)
{
if (txn == NULL)
return;
DPRINTF("reset txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
mdb_txn_reset0(txn);
}
void
mdb_txn_abort(MDB_txn *txn)
{
if (txn == NULL)
return;
DPRINTF("abort txn %zu%c %p on mdbenv %p, root page %zu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *)txn, (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
mdb_txn_reset0(txn);
free(txn);
}
int
mdb_txn_commit(MDB_txn *txn)
{
int n, done;
unsigned int i;
ssize_t rc;
off_t size;
MDB_page *dp;
MDB_env *env;
pgno_t next;
MDB_cursor mc;
assert(txn != NULL);
assert(txn->mt_env != NULL);
env = txn->mt_env;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
mdb_txn_abort(txn);
return MDB_SUCCESS;
}
if (txn != env->me_txn) {
DPUTS("attempt to commit unknown transaction");
mdb_txn_abort(txn);
return EINVAL;
}
if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
DPUTS("error flag is set, can't commit");
mdb_txn_abort(txn);
return EINVAL;
}
if (!txn->mt_u.dirty_list[0].mid)
goto done;
DPRINTF("committing txn %zu %p on mdbenv %p, root page %zu",
txn->mt_txnid, (void *)txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root);
mdb_cursor_init(&mc, txn, FREE_DBI, NULL);
/* should only be one record now */
if (env->me_pghead) {
/* make sure first page of freeDB is touched and on freelist */
mdb_search_page(&mc, NULL, 1);
}
/* save to free list */
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
MDB_val key, data;
pgno_t i;
/* make sure last page of freeDB is touched and on freelist */
key.mv_size = MAXKEYSIZE+1;
key.mv_data = NULL;
mdb_search_page(&mc, &key, 1);
mdb_midl_sort(txn->mt_free_pgs);
#if DEBUG > 1
{
unsigned int i;
ID *idl = txn->mt_free_pgs;
DPRINTF("IDL write txn %zu root %zu num %zu",
txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
for (i=0; i<idl[0]; i++) {
DPRINTF("IDL %zu", idl[i+1]);
}
}
#endif
/* write to last page of freeDB */
key.mv_size = sizeof(pgno_t);
key.mv_data = &txn->mt_txnid;
data.mv_data = txn->mt_free_pgs;
/* The free list can still grow during this call,
* despite the pre-emptive touches above. So check
* and make sure the entire thing got written.
*/
do {
i = txn->mt_free_pgs[0];
data.mv_size = MDB_IDL_SIZEOF(txn->mt_free_pgs);
rc = mdb_cursor_put(&mc, &key, &data, 0);
if (rc) {
mdb_txn_abort(txn);
return rc;
}
} while (i != txn->mt_free_pgs[0]);
}
/* should only be one record now */
if (env->me_pghead) {
MDB_val key, data;
MDB_oldpages *mop;
mop = env->me_pghead;
key.mv_size = sizeof(pgno_t);
key.mv_data = &mop->mo_txnid;
data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
data.mv_data = mop->mo_pages;
mdb_cursor_put(&mc, &key, &data, 0);
free(env->me_pghead);
env->me_pghead = NULL;
}
/* Update DB root pointers. Their pages have already been
* touched so this is all in-place and cannot fail.
*/
{
MDB_dbi i;
MDB_val data;
data.mv_size = sizeof(MDB_db);
mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
for (i = 2; i < txn->mt_numdbs; i++) {
if (txn->mt_dbxs[i].md_dirty) {
data.mv_data = &txn->mt_dbs[i];
mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0);
}
}
}
/* Commit up to MDB_COMMIT_PAGES dirty pages to disk until done.
*/
next = 0;
i = 1;
do {
#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.
*/
OVERLAPPED ov;
memset(&ov, 0, sizeof(ov));
for (; i<=txn->mt_u.dirty_list[0].mid; i++) {
size_t wsize;
dp = txn->mt_u.dirty_list[i].mptr;
DPRINTF("committing page %zu", dp->mp_pgno);
size = dp->mp_pgno * env->me_psize;
ov.Offset = size & 0xffffffff;
ov.OffsetHigh = size >> 16;
ov.OffsetHigh >>= 16;
/* clear dirty flag */
dp->mp_flags &= ~P_DIRTY;
wsize = env->me_psize;
if (IS_OVERFLOW(dp)) wsize *= dp->mp_pages;
rc = WriteFile(env->me_fd, dp, wsize, NULL, &ov);
if (!rc) {
n = ErrCode();
DPRINTF("WriteFile: %d", n);
mdb_txn_abort(txn);
return n;
}
}
done = 1;
#else
struct iovec iov[MDB_COMMIT_PAGES];
n = 0;
done = 1;
size = 0;
for (; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
if (dp->mp_pgno != next) {
if (n) {
DPRINTF("committing %u dirty pages", n);
rc = writev(env->me_fd, iov, n);
if (rc != size) {
n = ErrCode();
if (rc > 0)
DPUTS("short write, filesystem full?");
else
DPRINTF("writev: %s", strerror(n));
mdb_txn_abort(txn);
return n;
}
n = 0;
size = 0;
}
lseek(env->me_fd, dp->mp_pgno * env->me_psize, SEEK_SET);
next = dp->mp_pgno;
}
DPRINTF("committing page %zu", dp->mp_pgno);
iov[n].iov_len = env->me_psize;
if (IS_OVERFLOW(dp)) iov[n].iov_len *= dp->mp_pages;
iov[n].iov_base = dp;
size += iov[n].iov_len;
next = dp->mp_pgno + (IS_OVERFLOW(dp) ? dp->mp_pages : 1);
/* clear dirty flag */
dp->mp_flags &= ~P_DIRTY;
if (++n >= MDB_COMMIT_PAGES) {
done = 0;
i++;
break;
}
}
if (n == 0)
break;
DPRINTF("committing %u dirty pages", n);
rc = writev(env->me_fd, iov, n);
if (rc != size) {
n = ErrCode();
if (rc > 0)
DPUTS("short write, filesystem full?");
else
DPRINTF("writev: %s", strerror(n));
mdb_txn_abort(txn);
return n;
}
#endif
} while (!done);
/* Drop the dirty pages.
*/
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
if (!IS_OVERFLOW(dp) || dp->mp_pages == 1) {
dp->mp_next = txn->mt_env->me_dpages;
txn->mt_env->me_dpages = dp;
} else {
free(dp);
}
txn->mt_u.dirty_list[i].mid = 0;
}
txn->mt_u.dirty_list[0].mid = 0;
if ((n = mdb_env_sync(env, 0)) != 0 ||
(n = mdb_env_write_meta(txn)) != MDB_SUCCESS) {
mdb_txn_abort(txn);
return n;
}
done:
env->me_txn = NULL;
/* update the DB tables */
{
int toggle = !env->me_db_toggle;
MDB_db *ip, *jp;
MDB_dbi i;
ip = &env->me_dbs[toggle][2];
jp = &txn->mt_dbs[2];
LAZY_RWLOCK_WRLOCK(&env->me_dblock);
for (i = 2; i < txn->mt_numdbs; i++) {
if (ip->md_root != jp->md_root)
*ip = *jp;
ip++; jp++;
}
for (i = 2; i < txn->mt_numdbs; i++) {
if (txn->mt_dbxs[i].md_dirty)
txn->mt_dbxs[i].md_dirty = 0;
}
env->me_db_toggle = toggle;
env->me_numdbs = txn->mt_numdbs;
LAZY_RWLOCK_UNLOCK(&env->me_dblock);
}
UNLOCK_MUTEX_W(env);
free(txn);
return MDB_SUCCESS;
}
/** Read the environment parameters of a DB environment before
* mapping it into memory.
* @param[in] env the environment handle
* @param[out] meta address of where to store the meta information
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_read_header(MDB_env *env, MDB_meta *meta)
{
char page[PAGESIZE];
MDB_page *p;
MDB_meta *m;
int rc, err;
/* We don't know the page size yet, so use a minimum value.
*/
#ifdef _WIN32
if (!ReadFile(env->me_fd, page, PAGESIZE, (DWORD *)&rc, NULL) || rc == 0)
#else
if ((rc = read(env->me_fd, page, PAGESIZE)) == 0)
#endif
{
return ENOENT;
}
else if (rc != PAGESIZE) {
err = ErrCode();
if (rc > 0)
err = EINVAL;
DPRINTF("read: %s", strerror(err));
return err;
}
p = (MDB_page *)page;
if (!F_ISSET(p->mp_flags, P_META)) {
DPRINTF("page %zu not a meta page", p->mp_pgno);
return EINVAL;
}
m = METADATA(p);
if (m->mm_magic != MDB_MAGIC) {
DPUTS("meta has invalid magic");
return EINVAL;
}
if (m->mm_version != MDB_VERSION) {
DPRINTF("database is version %u, expected version %u",
m->mm_version, MDB_VERSION);
return MDB_VERSION_MISMATCH;
}
memcpy(meta, m, sizeof(*m));
return 0;
}
/** Write the environment parameters of a freshly created DB environment.
* @param[in] env the environment handle
* @param[out] meta address of where to store the meta information
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
{
MDB_page *p, *q;
MDB_meta *m;
int rc;
unsigned int psize;
DPUTS("writing new meta page");
GET_PAGESIZE(psize);
meta->mm_magic = MDB_MAGIC;
meta->mm_version = MDB_VERSION;
meta->mm_psize = psize;
meta->mm_last_pg = 1;
meta->mm_flags = env->me_flags & 0xffff;
meta->mm_flags |= MDB_INTEGERKEY;
meta->mm_dbs[0].md_root = P_INVALID;
meta->mm_dbs[1].md_root = P_INVALID;
p = calloc(2, psize);
p->mp_pgno = 0;
p->mp_flags = P_META;
m = METADATA(p);
memcpy(m, meta, sizeof(*meta));
q = (MDB_page *)((char *)p + psize);
q->mp_pgno = 1;
q->mp_flags = P_META;
m = METADATA(q);
memcpy(m, meta, sizeof(*meta));
#ifdef _WIN32
{
DWORD len;
rc = WriteFile(env->me_fd, p, psize * 2, &len, NULL);
rc = (len == psize * 2) ? MDB_SUCCESS : ErrCode();
}
#else
rc = write(env->me_fd, p, psize * 2);
rc = (rc == (int)psize * 2) ? MDB_SUCCESS : ErrCode();
#endif
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;
off_t off;
int rc, len, toggle;
char *ptr;
#ifdef _WIN32
OVERLAPPED ov;
#endif
assert(txn != NULL);
assert(txn->mt_env != NULL);
toggle = !txn->mt_toggle;
DPRINTF("writing meta page %d for root page %zu",
toggle, txn->mt_dbs[MAIN_DBI].md_root);
env = txn->mt_env;
metab.mm_txnid = env->me_metas[toggle]->mm_txnid;
metab.mm_last_pg = env->me_metas[toggle]->mm_last_pg;
ptr = (char *)&meta;
off = offsetof(MDB_meta, mm_dbs[0].md_depth);
len = sizeof(MDB_meta) - off;
ptr += off;
meta.mm_dbs[0] = txn->mt_dbs[0];
meta.mm_dbs[1] = txn->mt_dbs[1];
meta.mm_last_pg = txn->mt_next_pgno - 1;
meta.mm_txnid = txn->mt_txnid;
if (toggle)
off += env->me_psize;
off += PAGEHDRSZ;
/* Write to the SYNC fd */
#ifdef _WIN32
{
memset(&ov, 0, sizeof(ov));
ov.Offset = off;
WriteFile(env->me_mfd, ptr, len, (DWORD *)&rc, &ov);
}
#else
rc = pwrite(env->me_mfd, ptr, len, off);
#endif
if (rc != len) {
int r2;
rc = ErrCode();
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
WriteFile(env->me_fd, ptr, len, NULL, &ov);
#else
r2 = pwrite(env->me_fd, ptr, len, off);
#endif
env->me_flags |= MDB_FATAL_ERROR;
return rc;
}
/* 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.
*/
LAZY_MUTEX_LOCK(&env->me_txns->mti_mutex);
txn->mt_env->me_txns->mti_me_toggle = toggle;
txn->mt_env->me_txns->mti_txnid = txn->mt_txnid;
LAZY_MUTEX_UNLOCK(&env->me_txns->mti_mutex);
return MDB_SUCCESS;
}
/** Check both meta pages to see which one is newer.
* @param[in] env the environment handle
* @param[out] which address of where to store the meta toggle ID
* @return 0 on success, non-zero on failure.
*/
static int
mdb_env_read_meta(MDB_env *env, int *which)
{
int toggle = 0;
assert(env != NULL);
if (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid)
toggle = 1;
DPRINTF("Using meta page %d", toggle);
*which = toggle;
return MDB_SUCCESS;
}
int
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 = 2;
e->me_fd = INVALID_HANDLE_VALUE;
e->me_lfd = INVALID_HANDLE_VALUE;
e->me_mfd = INVALID_HANDLE_VALUE;
*env = e;
return MDB_SUCCESS;
}
int
mdb_env_set_mapsize(MDB_env *env, size_t size)
{
if (env->me_map)
return EINVAL;
env->me_mapsize = size;
return MDB_SUCCESS;
}
int
mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs)
{
if (env->me_map)
return EINVAL;
env->me_maxdbs = dbs;
return MDB_SUCCESS;
}
int
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
mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers)
{
if (!env || !readers)
return EINVAL;
*readers = env->me_maxreaders;
return MDB_SUCCESS;
}
/** Further setup required for opening an MDB environment
*/
static int
mdb_env_open2(MDB_env *env, unsigned int flags)
{
int i, newenv = 0, toggle;
MDB_meta meta;
MDB_page *p;
env->me_flags = flags;
memset(&meta, 0, sizeof(meta));
if ((i = mdb_env_read_header(env, &meta)) != 0) {
if (i != ENOENT)
return i;
DPUTS("new mdbenv");
newenv = 1;
}
if (!env->me_mapsize) {
env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
}
#ifdef _WIN32
{
HANDLE mh;
LONG sizelo, sizehi;
sizelo = env->me_mapsize & 0xffffffff;
sizehi = env->me_mapsize >> 16; /* pointless on WIN32, only needed on W64 */
sizehi >>= 16;
/* Windows won't create mappings for zero length files.
* Just allocate the maxsize right now.
*/
if (newenv) {
SetFilePointer(env->me_fd, sizelo, sizehi ? &sizehi : NULL, 0);
if (!SetEndOfFile(env->me_fd))
return ErrCode();
SetFilePointer(env->me_fd, 0, NULL, 0);
}
mh = CreateFileMapping(env->me_fd, NULL, PAGE_READONLY,
sizehi, sizelo, NULL);
if (!mh)
return ErrCode();
env->me_map = MapViewOfFileEx(mh, FILE_MAP_READ, 0, 0, env->me_mapsize,
meta.mm_address);
CloseHandle(mh);
if (!env->me_map)
return ErrCode();
}
#else
i = MAP_SHARED;
if (meta.mm_address && (flags & MDB_FIXEDMAP))
i |= MAP_FIXED;
env->me_map = mmap(meta.mm_address, env->me_mapsize, PROT_READ, i,
env->me_fd, 0);
if (env->me_map == MAP_FAILED)
return ErrCode();
#endif
if (newenv) {
meta.mm_mapsize = env->me_mapsize;
if (flags & MDB_FIXEDMAP)
meta.mm_address = env->me_map;
i = mdb_env_init_meta(env, &meta);
if (i != MDB_SUCCESS) {
munmap(env->me_map, env->me_mapsize);
return i;
}
}
env->me_psize = meta.mm_psize;
env->me_maxpg = env->me_mapsize / env->me_psize;
p = (MDB_page *)env->me_map;
env->me_metas[0] = METADATA(p);
env->me_metas[1] = (MDB_meta *)((char *)env->me_metas[0] + meta.mm_psize);
if ((i = mdb_env_read_meta(env, &toggle)) != 0)
return i;
DPRINTF("opened database version %u, pagesize %u",
env->me_metas[toggle]->mm_version, env->me_psize);
DPRINTF("depth: %u", env->me_metas[toggle]->mm_dbs[MAIN_DBI].md_depth);
DPRINTF("entries: %zu", env->me_metas[toggle]->mm_dbs[MAIN_DBI].md_entries);
DPRINTF("branch pages: %zu", env->me_metas[toggle]->mm_dbs[MAIN_DBI].md_branch_pages);
DPRINTF("leaf pages: %zu", env->me_metas[toggle]->mm_dbs[MAIN_DBI].md_leaf_pages);
DPRINTF("overflow pages: %zu", env->me_metas[toggle]->mm_dbs[MAIN_DBI].md_overflow_pages);
DPRINTF("root: %zu", env->me_metas[toggle]->mm_dbs[MAIN_DBI].md_root);
return MDB_SUCCESS;
}
#ifndef _WIN32
/* Windows doesn't support destructor callbacks for thread-specific storage */
static void
mdb_env_reader_dest(void *ptr)
{
MDB_reader *reader = ptr;
reader->mr_txnid = 0;
reader->mr_pid = 0;
reader->mr_tid = 0;
}
#endif
/* downgrade the exclusive lock on the region back to shared */
static void
mdb_env_share_locks(MDB_env *env)
{
int toggle = 0;
if (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid)
toggle = 1;
env->me_txns->mti_me_toggle = toggle;
env->me_txns->mti_txnid = env->me_metas[toggle]->mm_txnid;
#ifdef _WIN32
{
OVERLAPPED ov;
/* First acquire a shared lock. The Unlock will
* then release the existing exclusive lock.
*/
memset(&ov, 0, sizeof(ov));
LockFileEx(env->me_lfd, 0, 0, 1, 0, &ov);
UnlockFile(env->me_lfd, 0, 0, 1, 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;
fcntl(env->me_lfd, F_SETLK, &lock_info);
}
#endif
}
static int
mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
{
int rc;
off_t size, rsize;
*excl = 0;
#ifdef _WIN32
if ((env->me_lfd = CreateFile(lpath, GENERIC_READ|GENERIC_WRITE,
FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL, NULL)) == INVALID_HANDLE_VALUE) {
rc = ErrCode();
return rc;
}
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
{
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)) {
rc = ErrCode();
goto fail;
}
}
}
size = GetFileSize(env->me_lfd, NULL);
#else
if ((env->me_lfd = open(lpath, O_RDWR|O_CREAT, mode)) == -1) {
rc = ErrCode();
return rc;
}
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
{
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;
rc = fcntl(env->me_lfd, F_SETLK, &lock_info);
if (rc == 0) {
*excl = 1;
} else {
lock_info.l_type = F_RDLCK;
rc = fcntl(env->me_lfd, F_SETLKW, &lock_info);
if (rc) {
rc = ErrCode();
goto fail;
}
}
}
size = lseek(env->me_lfd, 0, SEEK_END);
#endif
rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
if (size < rsize && *excl) {
#ifdef _WIN32
SetFilePointer(env->me_lfd, rsize, NULL, 0);
if (!SetEndOfFile(env->me_lfd)) {
rc = ErrCode();
goto fail;
}
#else
if (ftruncate(env->me_lfd, rsize) != 0) {
rc = ErrCode();
goto fail;
}
#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) {
rc = ErrCode();
goto fail;
}
env->me_txns = MapViewOfFileEx(mh, FILE_MAP_WRITE, 0, 0, rsize, NULL);
CloseHandle(mh);
if (!env->me_txns) {
rc = ErrCode();
goto fail;
}
}
#else
env->me_txns = mmap(0, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
env->me_lfd, 0);
if (env->me_txns == MAP_FAILED) {
rc = ErrCode();
goto fail;
}
#endif
if (*excl) {
#ifdef _WIN32
char *ptr;
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;
}
/* FIXME: only using up to 20 characters of the env path here,
* probably not enough to assure uniqueness...
*/
sprintf(env->me_txns->mti_rmname, "Global\\MDBr%.20s", lpath);
ptr = env->me_txns->mti_rmname + sizeof("Global\\MDBr");
while ((ptr = strchr(ptr, '\\')))
*ptr++ = '/';
env->me_rmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
if (!env->me_rmutex) {
rc = ErrCode();
goto fail;
}
sprintf(env->me_txns->mti_rmname, "Global\\MDBw%.20s", lpath);
ptr = env->me_txns->mti_rmname + sizeof("Global\\MDBw");
while ((ptr = strchr(ptr, '\\')))
*ptr++ = '/';
env->me_wmutex = CreateMutex(&mdb_all_sa, FALSE, env->me_txns->mti_rmname);
if (!env->me_wmutex) {
rc = ErrCode();
goto fail;
}
#else
pthread_mutexattr_t mattr;
pthread_mutexattr_init(&mattr);
rc = pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
if (rc) {
goto fail;
}
pthread_mutex_init(&env->me_txns->mti_mutex, &mattr);
pthread_mutex_init(&env->me_txns->mti_wmutex, &mattr);
#endif
env->me_txns->mti_version = MDB_VERSION;
env->me_txns->mti_magic = MDB_MAGIC;
env->me_txns->mti_txnid = 0;
env->me_txns->mti_numreaders = 0;
env->me_txns->mti_me_toggle = 0;
} else {
if (env->me_txns->mti_magic != MDB_MAGIC) {
DPUTS("lock region has invalid magic");
rc = EINVAL;
goto fail;
}
if (env->me_txns->mti_version != MDB_VERSION) {
DPRINTF("lock region is version %u, expected version %u",
env->me_txns->mti_version, MDB_VERSION);
rc = MDB_VERSION_MISMATCH;
goto fail;
}
rc = ErrCode();
if (rc != EACCES && rc != EAGAIN) {
goto fail;
}
#ifdef _WIN32
env->me_rmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_rmname);
if (!env->me_rmutex) {
rc = ErrCode();
goto fail;
}
env->me_wmutex = OpenMutex(SYNCHRONIZE, FALSE, env->me_txns->mti_wmname);
if (!env->me_wmutex) {
rc = ErrCode();
goto fail;
}
#endif
}
return MDB_SUCCESS;
fail:
close(env->me_lfd);
env->me_lfd = INVALID_HANDLE_VALUE;
return rc;
}
/** The name of the lock file in the DB environment */
#define LOCKNAME "/lock.mdb"
/** The name of the data file in the DB environment */
#define DATANAME "/data.mdb"
int
mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mode_t mode)
{
int oflags, rc, len, excl;
char *lpath, *dpath;
len = strlen(path);
lpath = malloc(len + sizeof(LOCKNAME) + len + sizeof(DATANAME));
if (!lpath)
return ENOMEM;
dpath = lpath + len + sizeof(LOCKNAME);
sprintf(lpath, "%s" LOCKNAME, path);
sprintf(dpath, "%s" DATANAME, path);
rc = mdb_env_setup_locks(env, lpath, mode, &excl);
if (rc)
goto leave;
#ifdef _WIN32
if (F_ISSET(flags, MDB_RDONLY)) {
oflags = GENERIC_READ;
len = OPEN_EXISTING;
} else {
oflags = GENERIC_READ|GENERIC_WRITE;
len = OPEN_ALWAYS;
}
mode = FILE_ATTRIBUTE_NORMAL;
if ((env->me_fd = CreateFile(dpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,
NULL, len, mode, NULL)) == INVALID_HANDLE_VALUE) {
rc = ErrCode();
goto leave;
}
#else
if (F_ISSET(flags, MDB_RDONLY))
oflags = O_RDONLY;
else
oflags = O_RDWR | O_CREAT;
if ((env->me_fd = open(dpath, oflags, mode)) == -1) {
rc = ErrCode();
goto leave;
}
#endif
if ((rc = mdb_env_open2(env, flags)) == MDB_SUCCESS) {
/* synchronous fd for meta writes */
#ifdef _WIN32
if (!(flags & (MDB_RDONLY|MDB_NOSYNC)))
mode |= FILE_FLAG_WRITE_THROUGH;
if ((env->me_mfd = CreateFile(dpath, oflags, FILE_SHARE_READ|FILE_SHARE_WRITE,
NULL, len, mode, NULL)) == INVALID_HANDLE_VALUE) {
rc = ErrCode();
goto leave;
}
#else
if (!(flags & (MDB_RDONLY|MDB_NOSYNC)))
oflags |= MDB_DSYNC;
if ((env->me_mfd = open(dpath, oflags, mode)) == -1) {
rc = ErrCode();
goto leave;
}
#endif
env->me_path = strdup(path);
DPRINTF("opened dbenv %p", (void *) env);
pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
LAZY_RWLOCK_INIT(&env->me_dblock, NULL);
if (excl)
mdb_env_share_locks(env);
env->me_dbxs = calloc(env->me_maxdbs, sizeof(MDB_dbx));
env->me_dbs[0] = calloc(env->me_maxdbs, sizeof(MDB_db));
env->me_dbs[1] = calloc(env->me_maxdbs, sizeof(MDB_db));
env->me_numdbs = 2;
}
leave:
if (rc) {
if (env->me_fd != INVALID_HANDLE_VALUE) {
close(env->me_fd);
env->me_fd = INVALID_HANDLE_VALUE;
}
if (env->me_lfd != INVALID_HANDLE_VALUE) {
close(env->me_lfd);
env->me_lfd = INVALID_HANDLE_VALUE;
}
}
free(lpath);
return rc;
}
void
mdb_env_close(MDB_env *env)
{
MDB_page *dp;
if (env == NULL)
return;
while (env->me_dpages) {
dp = env->me_dpages;
env->me_dpages = dp->mp_next;
free(dp);
}
free(env->me_dbs[1]);
free(env->me_dbs[0]);
free(env->me_dbxs);
free(env->me_path);
LAZY_RWLOCK_DESTROY(&env->me_dblock);
pthread_key_delete(env->me_txkey);
if (env->me_map) {
munmap(env->me_map, env->me_mapsize);
}
close(env->me_mfd);
close(env->me_fd);
if (env->me_txns) {
pid_t pid = getpid();
unsigned int i;
for (i=0; i<env->me_txns->mti_numreaders; i++)
if (env->me_txns->mti_readers[i].mr_pid == pid)
env->me_txns->mti_readers[i].mr_pid = 0;
munmap(env->me_txns, (env->me_maxreaders-1)*sizeof(MDB_reader)+sizeof(MDB_txninfo));
}
close(env->me_lfd);
free(env);
}
/* only for aligned ints */
static int
intcmp(const MDB_val *a, const MDB_val *b)
{
if (a->mv_size == sizeof(long))
{
unsigned long *la, *lb;
la = a->mv_data;
lb = b->mv_data;
return *la - *lb;
} else {
unsigned int *ia, *ib;
ia = a->mv_data;
ib = b->mv_data;
return *ia - *ib;
}
}
/* ints must always be the same size */
static int
cintcmp(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
return memcmp(a->mv_data, b->mv_data, a->mv_size);
#endif
}
static int
memncmp(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;
}
static int
memnrcmp(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 leaf 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).
* If kip is non-null, stores the index of the found entry in *kip.
* If no entry larger or equal to the key is found, returns NULL.
*/
static MDB_node *
mdb_search_node(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 page %zu",
nkeys, IS_LEAF(mp) ? "leaf" : "branch",
mp->mp_pgno);
assert(nkeys > 0);
low = IS_LEAF(mp) ? 0 : 1;
high = nkeys - 1;
cmp = mc->mc_dbx->md_cmp;
if (IS_LEAF2(mp)) {
nodekey.mv_size = mc->mc_db->md_pad;
node = NODEPTR(mp, 0); /* fake */
}
while (low <= high) {
i = (low + high) >> 1;
if (IS_LEAF2(mp)) {
nodekey.mv_data = LEAF2KEY(mp, i, nodekey.mv_size);
} else {
node = NODEPTR(mp, i);
nodekey.mv_size = node->mn_ksize;
nodekey.mv_data = NODEKEY(node);
}
rc = cmp(key, &nodekey);
#if DEBUG
if (IS_LEAF(mp))
DPRINTF("found leaf index %u [%s], rc = %i",
i, DKEY(&nodekey), rc);
else
DPRINTF("found branch index %u [%s -> %zu], 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);
/* 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;
}
static void
cursor_pop_page(MDB_cursor *mc)
{
MDB_page *top;
if (mc->mc_snum) {
top = mc->mc_pg[mc->mc_top];
mc->mc_snum--;
if (mc->mc_snum)
mc->mc_top--;
DPRINTF("popped page %zu off db %u cursor %p", top->mp_pgno,
mc->mc_dbi, (void *) mc);
}
}
static int
cursor_push_page(MDB_cursor *mc, MDB_page *mp)
{
DPRINTF("pushing page %zu on db %u cursor %p", mp->mp_pgno,
mc->mc_dbi, (void *) mc);
if (mc->mc_snum >= CURSOR_STACK) {
assert(mc->mc_snum < CURSOR_STACK);
return ENOMEM;
}
mc->mc_top = mc->mc_snum++;
mc->mc_pg[mc->mc_top] = mp;
mc->mc_ki[mc->mc_top] = 0;
return MDB_SUCCESS;
}
static int
mdb_get_page(MDB_txn *txn, pgno_t pgno, MDB_page **ret)
{
MDB_page *p = NULL;
if (!F_ISSET(txn->mt_flags, MDB_TXN_RDONLY) && txn->mt_u.dirty_list[0].mid) {
unsigned x;
x = mdb_mid2l_search(txn->mt_u.dirty_list, pgno);
if (x <= txn->mt_u.dirty_list[0].mid && txn->mt_u.dirty_list[x].mid == pgno) {
p = txn->mt_u.dirty_list[x].mptr;
}
}
if (!p) {
if (pgno <= txn->mt_env->me_metas[txn->mt_toggle]->mm_last_pg)
p = (MDB_page *)(txn->mt_env->me_map + txn->mt_env->me_psize * pgno);
}
*ret = p;
if (!p) {
DPRINTF("page %zu not found", pgno);
assert(p != NULL);
}
return (p != NULL) ? MDB_SUCCESS : MDB_PAGE_NOTFOUND;
}
static int
mdb_search_page_root(MDB_cursor *mc, MDB_val *key, int modify)
{
MDB_page *mp = mc->mc_pg[mc->mc_top];
DKBUF;
int rc;
while (IS_BRANCH(mp)) {
MDB_node *node;
DPRINTF("branch page %zu has %u keys", mp->mp_pgno, NUMKEYS(mp));
assert(NUMKEYS(mp) > 1);
DPRINTF("found index 0 to page %zu", NODEPGNO(NODEPTR(mp, 0)));
if (key == NULL) /* Initialize cursor to first page. */
mc->mc_ki[mc->mc_top] = 0;
else if (key->mv_size > MAXKEYSIZE && key->mv_data == NULL) {
/* cursor to last page */
mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
} else {
int exact;
node = mdb_search_node(mc, key, &exact);
if (node == NULL)
mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
else if (!exact) {
assert(mc->mc_ki[mc->mc_top] > 0);
mc->mc_ki[mc->mc_top]--;
}
}
if (key)
DPRINTF("following index %u for key [%s]",
mc->mc_ki[mc->mc_top], DKEY(key));
assert(mc->mc_ki[mc->mc_top] < NUMKEYS(mp));
node = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if ((rc = mdb_get_page(mc->mc_txn, NODEPGNO(node), &mp)))
return rc;
if ((rc = cursor_push_page(mc, mp)))
return rc;
if (modify) {
if ((rc = mdb_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);
return MDB_CORRUPTED;
}
DPRINTF("found leaf page %zu for key [%s]", mp->mp_pgno,
key ? DKEY(key) : NULL);
return MDB_SUCCESS;
}
/* Search for the page a given key should be in.
* Pushes parent pages on the cursor stack.
* If key is NULL, search for the lowest page (used by mdb_cursor_first).
* If modify is true, visited pages are updated with new page numbers.
*/
static int
mdb_search_page(MDB_cursor *mc, MDB_val *key, int modify)
{
int rc;
pgno_t root;
/* Make sure the txn is still viable, then find the root from
* the txn's db table.
*/
if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_ERROR)) {
DPUTS("transaction has failed, must abort");
return EINVAL;
} else
root = mc->mc_db->md_root;
if (root == P_INVALID) { /* Tree is empty. */
DPUTS("tree is empty");
return MDB_NOTFOUND;
}
if ((rc = mdb_get_page(mc->mc_txn, root, &mc->mc_pg[0])))
return rc;
mc->mc_snum = 1;
mc->mc_top = 0;
DPRINTF("db %u root page %zu has flags 0x%X",
mc->mc_dbi, root, mc->mc_pg[0]->mp_flags);
if (modify) {
/* For sub-databases, update main root first */
if (mc->mc_dbi > MAIN_DBI && !mc->mc_dbx->md_dirty) {
MDB_cursor mc2;
mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
rc = mdb_search_page(&mc2, &mc->mc_dbx->md_name, 1);
if (rc)
return rc;
mc->mc_dbx->md_dirty = 1;
}
if (!F_ISSET(mc->mc_pg[0]->mp_flags, P_DIRTY)) {
if ((rc = mdb_touch(mc)))
return rc;
mc->mc_db->md_root = mc->mc_pg[0]->mp_pgno;
}
}
return mdb_search_page_root(mc, key, modify);
}
static int
mdb_read_data(MDB_txn *txn, MDB_node *leaf, MDB_val *data)
{
MDB_page *omp; /* overflow mpage */
pgno_t pgno;
int rc;
if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
data->mv_size = NODEDSZ(leaf);
data->mv_data = NODEDATA(leaf);
return MDB_SUCCESS;
}
/* Read overflow data.
*/
data->mv_size = NODEDSZ(leaf);
memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
if ((rc = mdb_get_page(txn, pgno, &omp))) {
DPRINTF("read overflow page %zu failed", pgno);
return rc;
}
data->mv_data = METADATA(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;
DKBUF;
assert(key);
assert(data);
DPRINTF("===> get db %u key [%s]", dbi, DKEY(key));
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
mdb_cursor_init(&mc, txn, dbi, &mx);
return mdb_cursor_set(&mc, key, data, MDB_SET, &exact);
}
static int
mdb_sibling(MDB_cursor *mc, int move_right)
{
int rc;
MDB_node *indx;
MDB_page *mp;
if (mc->mc_snum < 2) {
return MDB_NOTFOUND; /* root has no siblings */
}
cursor_pop_page(mc);
DPRINTF("parent page is page %zu, 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_sibling(mc, move_right)) != MDB_SUCCESS)
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]);
}
assert(IS_BRANCH(mc->mc_pg[mc->mc_top]));
indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if ((rc = mdb_get_page(mc->mc_txn, NODEPGNO(indx), &mp)))
return rc;;
cursor_push_page(mc, mp);
return MDB_SUCCESS;
}
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_EOF) {
return MDB_NOTFOUND;
}
assert(mc->mc_flags & C_INITIALIZED);
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_NEXT || op == MDB_NEXT_DUP) {
rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
if (op != MDB_NEXT || rc == MDB_SUCCESS)
return rc;
}
} else {
mc->mc_xcursor->mx_cursor.mc_flags = 0;
if (op == MDB_NEXT_DUP)
return MDB_NOTFOUND;
}
}
DPRINTF("cursor_next: top page is %zu in cursor %p", mp->mp_pgno, (void *) mc);
if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
DPUTS("=====> move to next sibling page");
if (mdb_sibling(mc, 1) != MDB_SUCCESS) {
mc->mc_flags |= C_EOF;
return MDB_NOTFOUND;
}
mp = mc->mc_pg[mc->mc_top];
DPRINTF("next page is %zu, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]);
} else
mc->mc_ki[mc->mc_top]++;
DPRINTF("==> cursor points to page %zu with %u keys, key index %u",
mp->mp_pgno, 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;
}
assert(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_read_data(mc->mc_txn, 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_SET_KEY(leaf, key);
return MDB_SUCCESS;
}
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;
assert(mc->mc_flags & C_INITIALIZED);
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 (op == MDB_PREV || op == MDB_PREV_DUP) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
if (op != MDB_PREV || rc == MDB_SUCCESS)
return rc;
} else {
mc->mc_xcursor->mx_cursor.mc_flags = 0;
if (op == MDB_PREV_DUP)
return MDB_NOTFOUND;
}
}
}
DPRINTF("cursor_prev: top page is %zu in cursor %p", mp->mp_pgno, (void *) mc);
if (mc->mc_ki[mc->mc_top] == 0) {
DPUTS("=====> move to prev sibling page");
if (mdb_sibling(mc, 0) != MDB_SUCCESS) {
mc->mc_flags &= ~C_INITIALIZED;
return MDB_NOTFOUND;
}
mp = mc->mc_pg[mc->mc_top];
mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
DPRINTF("prev page is %zu, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]);
} else
mc->mc_ki[mc->mc_top]--;
mc->mc_flags &= ~C_EOF;
DPRINTF("==> cursor points to page %zu with %u keys, key index %u",
mp->mp_pgno, 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;
}
assert(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_read_data(mc->mc_txn, 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_SET_KEY(leaf, key);
return MDB_SUCCESS;
}
static int
mdb_cursor_set(MDB_cursor *mc, MDB_val *key, MDB_val *data,
MDB_cursor_op op, int *exactp)
{
int rc;
MDB_node *leaf;
DKBUF;
assert(mc);
assert(key);
assert(key->mv_size > 0);
/* See if we're already on the right page */
if (mc->mc_flags & C_INITIALIZED) {
MDB_val nodekey;
if (mc->mc_pg[mc->mc_top]->mp_flags & P_LEAF2) {
nodekey.mv_size = mc->mc_db->md_pad;
nodekey.mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, nodekey.mv_size);
} else {
leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
MDB_SET_KEY(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;
set1:
if (exactp)
*exactp = 1;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
goto set3;
}
if (rc > 0) {
unsigned int i;
if (NUMKEYS(mc->mc_pg[mc->mc_top]) > 1) {
if (mc->mc_pg[mc->mc_top]->mp_flags & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top],
NUMKEYS(mc->mc_pg[mc->mc_top])-1, nodekey.mv_size);
} else {
leaf = NODEPTR(mc->mc_pg[mc->mc_top], NUMKEYS(mc->mc_pg[mc->mc_top])-1);
MDB_SET_KEY(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] = NUMKEYS(mc->mc_pg[mc->mc_top])-1;
goto set1;
}
if (rc < 0) {
/* This is definitely the right page, skip search_page */
rc = 0;
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] = NUMKEYS(mc->mc_pg[mc->mc_top]);
return MDB_NOTFOUND;
}
}
}
rc = mdb_search_page(mc, key, 0);
if (rc != MDB_SUCCESS)
return rc;
assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
set2:
leaf = mdb_search_node(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_sibling(mc, 1)) != MDB_SUCCESS)
return rc; /* no entries matched */
mc->mc_ki[mc->mc_top] = 0;
assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
}
set3:
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
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 (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_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 d2;
if ((rc = mdb_read_data(mc->mc_txn, leaf, &d2)) != MDB_SUCCESS)
return rc;
rc = mc->mc_dbx->md_dcmp(data, &d2);
if (rc) {
if (op == MDB_GET_BOTH || rc > 0)
return MDB_NOTFOUND;
}
} else {
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags = 0;
if ((rc = mdb_read_data(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
/* The key already matches in all other cases */
if (op == MDB_SET_RANGE)
MDB_SET_KEY(leaf, key);
DPRINTF("==> cursor placed on key [%s]", DKEY(key));
return rc;
}
static int
mdb_cursor_first(MDB_cursor *mc, MDB_val *key, MDB_val *data)
{
int rc;
MDB_node *leaf;
rc = mdb_search_page(mc, NULL, 0);
if (rc != MDB_SUCCESS)
return rc;
assert(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 (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags = 0;
if ((rc = mdb_read_data(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_SET_KEY(leaf, key);
return MDB_SUCCESS;
}
static int
mdb_cursor_last(MDB_cursor *mc, MDB_val *key, MDB_val *data)
{
int rc;
MDB_node *leaf;
MDB_val lkey;
lkey.mv_size = MAXKEYSIZE+1;
lkey.mv_data = NULL;
rc = mdb_search_page(mc, &lkey, 0);
if (rc != MDB_SUCCESS)
return rc;
assert(IS_LEAF(mc->mc_pg[mc->mc_top]));
leaf = NODEPTR(mc->mc_pg[mc->mc_top], NUMKEYS(mc->mc_pg[mc->mc_top])-1);
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
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 (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags = 0;
if ((rc = mdb_read_data(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_SET_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;
assert(mc);
switch (op) {
case MDB_GET_BOTH:
case MDB_GET_BOTH_RANGE:
if (data == NULL || mc->mc_xcursor == NULL) {
rc = EINVAL;
break;
}
/* FALLTHRU */
case MDB_SET:
case MDB_SET_RANGE:
if (key == NULL || key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
rc = EINVAL;
} else if (op == MDB_SET_RANGE)
rc = mdb_cursor_set(mc, key, data, op, NULL);
else
rc = mdb_cursor_set(mc, key, data, op, &exact);
break;
case MDB_GET_MULTIPLE:
if (data == NULL ||
!(mc->mc_db->md_flags & MDB_DUPFIXED) ||
!(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
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 ||
!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
rc = EINVAL;
break;
}
if (!(mc->mc_flags & C_INITIALIZED))
rc = mdb_cursor_first(mc, key, data);
else
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_NEXT:
case MDB_NEXT_DUP:
case MDB_NEXT_NODUP:
if (!(mc->mc_flags & C_INITIALIZED))
rc = mdb_cursor_first(mc, key, data);
else
rc = mdb_cursor_next(mc, key, data, op);
break;
case MDB_PREV:
case MDB_PREV_DUP:
case MDB_PREV_NODUP:
if (!(mc->mc_flags & C_INITIALIZED) || (mc->mc_flags & C_EOF))
rc = mdb_cursor_last(mc, key, data);
else
rc = mdb_cursor_prev(mc, key, data, op);
break;
case MDB_FIRST:
rc = mdb_cursor_first(mc, key, data);
break;
case MDB_FIRST_DUP:
if (data == NULL ||
!(mc->mc_db->md_flags & MDB_DUPSORT) ||
!(mc->mc_flags & C_INITIALIZED) ||
!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
break;
case MDB_LAST:
rc = mdb_cursor_last(mc, key, data);
break;
case MDB_LAST_DUP:
if (data == NULL ||
!(mc->mc_db->md_flags & MDB_DUPSORT) ||
!(mc->mc_flags & C_INITIALIZED) ||
!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
break;
default:
DPRINTF("unhandled/unimplemented cursor operation %u", op);
rc = EINVAL;
break;
}
return rc;
}
static int
mdb_cursor_touch(MDB_cursor *mc)
{
int rc;
if (mc->mc_dbi > MAIN_DBI && !mc->mc_dbx->md_dirty) {
MDB_cursor mc2;
mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
rc = mdb_search_page(&mc2, &mc->mc_dbx->md_name, 1);
if (rc)
return rc;
mc->mc_dbx->md_dirty = 1;
}
for (mc->mc_top = 0; mc->mc_top < mc->mc_snum; mc->mc_top++) {
if (!F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY)) {
rc = mdb_touch(mc);
if (rc)
return rc;
if (!mc->mc_top) {
mc->mc_db->md_root =
mc->mc_pg[mc->mc_top]->mp_pgno;
}
}
}
mc->mc_top = mc->mc_snum-1;
return MDB_SUCCESS;
}
int
mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data,
unsigned int flags)
{
MDB_node *leaf;
MDB_val xdata, *rdata, dkey;
MDB_db dummy;
char dbuf[PAGESIZE];
int do_sub = 0;
size_t nsize;
DKBUF;
int rc, rc2;
if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_RDONLY))
return EACCES;
DPRINTF("==> put db %u key [%s], size %zu, data size %zu",
mc->mc_dbi, DKEY(key), key->mv_size, 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) {
MDB_page *np;
/* new database, write a root leaf page */
DPUTS("allocating new root leaf page");
if ((np = mdb_new_page(mc, P_LEAF, 1)) == NULL) {
return ENOMEM;
}
mc->mc_snum = 0;
cursor_push_page(mc, np);
mc->mc_db->md_root = np->mp_pgno;
mc->mc_db->md_depth++;
mc->mc_dbx->md_dirty = 1;
if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED))
== MDB_DUPFIXED)
np->mp_flags |= P_LEAF2;
mc->mc_flags |= C_INITIALIZED;
rc = MDB_NOTFOUND;
goto top;
} else {
int exact = 0;
MDB_val d2;
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;
}
/* Cursor is positioned, now make sure all pages are writable */
rc2 = mdb_cursor_touch(mc);
if (rc2)
return rc2;
top:
/* The key already exists */
if (rc == MDB_SUCCESS) {
/* there's only a key anyway, so this is a no-op */
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
unsigned int ksize = mc->mc_db->md_pad;
if (key->mv_size != ksize)
return EINVAL;
if (flags == MDB_CURRENT) {
char *ptr = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], ksize);
memcpy(ptr, key->mv_data, ksize);
}
return MDB_SUCCESS;
}
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
/* DB has dups? */
if (F_ISSET(mc->mc_db->md_flags, MDB_DUPSORT)) {
/* Was a single item before, must convert now */
if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
dkey.mv_size = NODEDSZ(leaf);
dkey.mv_data = dbuf;
memcpy(dbuf, NODEDATA(leaf), dkey.mv_size);
/* data matches, ignore it */
if (!mc->mc_dbx->md_dcmp(data, &dkey))
return (flags == MDB_NODUPDATA) ? MDB_KEYEXIST : MDB_SUCCESS;
memset(&dummy, 0, sizeof(dummy));
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
dummy.md_pad = data->mv_size;
dummy.md_flags = MDB_DUPFIXED;
if (mc->mc_db->md_flags & MDB_INTEGERDUP)
dummy.md_flags |= MDB_INTEGERKEY;
}
dummy.md_flags |= MDB_SUBDATA;
dummy.md_root = P_INVALID;
if (dkey.mv_size == sizeof(MDB_db)) {
memcpy(NODEDATA(leaf), &dummy, sizeof(dummy));
goto put_sub;
}
mdb_del_node(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
do_sub = 1;
rdata = &xdata;
xdata.mv_size = sizeof(MDB_db);
xdata.mv_data = &dummy;
/* new sub-DB, must fully init xcursor */
if (flags == MDB_CURRENT)
flags = 0;
goto new_sub;
}
goto put_sub;
}
/* same size, just replace it */
if (!F_ISSET(leaf->mn_flags, F_BIGDATA) &&
NODEDSZ(leaf) == data->mv_size) {
memcpy(NODEDATA(leaf), data->mv_data, data->mv_size);
goto done;
}
mdb_del_node(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], 0);
} else {
DPRINTF("inserting key at index %i", mc->mc_ki[mc->mc_top]);
}
rdata = data;
new_sub:
nsize = IS_LEAF2(mc->mc_pg[mc->mc_top]) ? key->mv_size : mdb_leaf_size(mc->mc_txn->mt_env, key, rdata);
if (SIZELEFT(mc->mc_pg[mc->mc_top]) < nsize) {
rc = mdb_split(mc, key, rdata, P_INVALID);
} else {
/* There is room already in this leaf page. */
rc = mdb_add_node(mc, mc->mc_ki[mc->mc_top], key, rdata, 0, 0);
}
if (rc != MDB_SUCCESS)
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
else {
/* Remember if we just added a subdatabase */
if (flags & F_SUBDATA) {
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
leaf->mn_flags |= F_SUBDATA;
}
/* 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) {
MDB_db *db;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
put_sub:
if (flags != MDB_CURRENT)
mdb_xcursor_init1(mc, leaf);
xdata.mv_size = 0;
xdata.mv_data = "";
if (flags == MDB_NODUPDATA)
flags = MDB_NOOVERWRITE;
/* converted, write the original data first */
if (dkey.mv_size) {
rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, &dkey, &xdata, flags);
if (rc)
return rc;
leaf->mn_flags |= F_DUPDATA;
}
rc = mdb_cursor_put(&mc->mc_xcursor->mx_cursor, data, &xdata, flags);
db = NODEDATA(leaf);
assert((db->md_flags & MDB_SUBDATA) == MDB_SUBDATA);
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
}
mc->mc_db->md_entries++;
}
done:
return rc;
}
int
mdb_cursor_del(MDB_cursor *mc, unsigned int flags)
{
MDB_node *leaf;
int rc;
if (F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_RDONLY))
return EACCES;
if (!mc->mc_flags & C_INITIALIZED)
return EINVAL;
rc = mdb_cursor_touch(mc);
if (rc)
return rc;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (!IS_LEAF2(mc->mc_pg[mc->mc_top]) && F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (flags != MDB_NODUPDATA) {
rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, 0);
/* If sub-DB still has entries, we're done */
if (mc->mc_xcursor->mx_db.md_root != P_INVALID) {
MDB_db *db = NODEDATA(leaf);
assert((db->md_flags & MDB_SUBDATA) == MDB_SUBDATA);
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
mc->mc_db->md_entries--;
return rc;
}
/* otherwise fall thru and delete the sub-DB */
}
/* add all the child DB's pages to the free list */
rc = mdb_search_page(&mc->mc_xcursor->mx_cursor, NULL, 0);
if (rc == MDB_SUCCESS) {
MDB_node *ni;
MDB_cursor *mx;
unsigned int i;
mx = &mc->mc_xcursor->mx_cursor;
mc->mc_db->md_entries -=
mx->mc_db->md_entries;
cursor_pop_page(mx);
while (mx->mc_snum > 1) {
for (i=0; i<NUMKEYS(mx->mc_pg[mx->mc_top]); i++) {
MDB_page *mp;
pgno_t pg;
ni = NODEPTR(mx->mc_pg[mx->mc_top], i);
pg = NODEPGNO(ni);
if ((rc = mdb_get_page(mc->mc_txn, pg, &mp)))
return rc;
/* free it */
mdb_midl_append(mc->mc_txn->mt_free_pgs, pg);
}
rc = mdb_sibling(mx, 1);
if (rc)
break;
}
/* free it */
mdb_midl_append(mc->mc_txn->mt_free_pgs,
mx->mc_db->md_root);
}
}
return mdb_del0(mc, leaf);
}
/* Allocate a page and initialize it
*/
static MDB_page *
mdb_new_page(MDB_cursor *mc, uint32_t flags, int num)
{
MDB_page *np;
if ((np = mdb_alloc_page(mc, num)) == NULL)
return NULL;
DPRINTF("allocated new mpage %zu, page size %u",
np->mp_pgno, mc->mc_txn->mt_env->me_psize);
np->mp_flags = flags | P_DIRTY;
np->mp_lower = PAGEHDRSZ;
np->mp_upper = mc->mc_txn->mt_env->me_psize;
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;
}
return np;
}
static size_t
mdb_leaf_size(MDB_env *env, MDB_val *key, MDB_val *data)
{
size_t sz;
sz = LEAFSIZE(key, data);
if (data->mv_size >= env->me_psize / MDB_MINKEYS) {
/* put on overflow page */
sz -= data->mv_size - sizeof(pgno_t);
}
sz += sz & 1;
return sz + sizeof(indx_t);
}
static size_t
mdb_branch_size(MDB_env *env, MDB_val *key)
{
size_t sz;
sz = INDXSIZE(key);
if (sz >= env->me_psize / MDB_MINKEYS) {
/* put on overflow page */
/* not implemented */
/* sz -= key->size - sizeof(pgno_t); */
}
return sz + sizeof(indx_t);
}
static int
mdb_add_node(MDB_cursor *mc, indx_t indx,
MDB_val *key, MDB_val *data, pgno_t pgno, uint8_t flags)
{
unsigned int i;
size_t node_size = NODESIZE;
indx_t ofs;
MDB_node *node;
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_page *ofp = NULL; /* overflow page */
DKBUF;
assert(mp->mp_upper >= mp->mp_lower);
DPRINTF("add to %s page %zu index %i, data size %zu key size %zu [%s]",
IS_LEAF(mp) ? "leaf" : "branch",
mp->mp_pgno, 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;
}
if (key != NULL)
node_size += key->mv_size;
if (IS_LEAF(mp)) {
assert(data);
if (F_ISSET(flags, F_BIGDATA)) {
/* Data already on overflow page. */
node_size += sizeof(pgno_t);
} else if (data->mv_size >= mc->mc_txn->mt_env->me_psize / MDB_MINKEYS) {
int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
/* Put data on overflow page. */
DPRINTF("data size is %zu, put on overflow page",
data->mv_size);
node_size += sizeof(pgno_t);
if ((ofp = mdb_new_page(mc, P_OVERFLOW, ovpages)) == NULL)
return ENOMEM;
DPRINTF("allocated overflow page %zu", ofp->mp_pgno);
flags |= F_BIGDATA;
} else {
node_size += data->mv_size;
}
}
node_size += node_size & 1;
if (node_size + sizeof(indx_t) > SIZELEFT(mp)) {
DPRINTF("not enough room in page %zu, got %u ptrs",
mp->mp_pgno, NUMKEYS(mp));
DPRINTF("upper - lower = %u - %u = %u", mp->mp_upper, mp->mp_lower,
mp->mp_upper - mp->mp_lower);
DPRINTF("node size = %zu", node_size);
return ENOSPC;
}
/* 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;
assert(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)) {
assert(key);
if (ofp == NULL) {
if (F_ISSET(flags, F_BIGDATA))
memcpy(node->mn_data + key->mv_size, data->mv_data,
sizeof(pgno_t));
else
memcpy(node->mn_data + key->mv_size, data->mv_data,
data->mv_size);
} else {
memcpy(node->mn_data + key->mv_size, &ofp->mp_pgno,
sizeof(pgno_t));
memcpy(METADATA(ofp), data->mv_data, data->mv_size);
}
}
return MDB_SUCCESS;
}
static void
mdb_del_node(MDB_page *mp, indx_t indx, int ksize)
{
unsigned int sz;
indx_t i, j, numkeys, ptr;
MDB_node *node;
char *base;
DPRINTF("delete node %u on %s page %zu", indx,
IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno);
assert(indx < NUMKEYS(mp));
if (IS_LEAF2(mp)) {
int x = NUMKEYS(mp) - 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(pgno_t);
else
sz += NODEDSZ(node);
}
sz += sz & 1;
ptr = mp->mp_ptrs[indx];
numkeys = NUMKEYS(mp);
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;
memmove(base + sz, base, ptr - mp->mp_upper);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += sz;
}
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+1;
mx->mx_dbx.md_parent = mc->mc_dbi;
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;
mx->mx_dbx.md_dirty = 0;
}
static void
mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node)
{
MDB_db *db = NODEDATA(node);
MDB_xcursor *mx = mc->mc_xcursor;
assert((db->md_flags & MDB_SUBDATA) == MDB_SUBDATA);
mx->mx_db = *db;
DPRINTF("Sub-db %u for db %u root page %zu", mx->mx_cursor.mc_dbi, mc->mc_dbi,
db->md_root);
if (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY))
mx->mx_dbx.md_dirty = 1;
mx->mx_dbx.md_name.mv_data = NODEKEY(node);
mx->mx_dbx.md_name.mv_size = node->mn_ksize;
mx->mx_cursor.mc_snum = 0;
mx->mx_cursor.mc_flags = 0;
}
static void
mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
{
mc->mc_dbi = dbi;
mc->mc_txn = txn;
mc->mc_db = &txn->mt_dbs[dbi];
mc->mc_dbx = &txn->mt_dbxs[dbi];
mc->mc_snum = 0;
mc->mc_flags = 0;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
assert(mx != NULL);
mc->mc_xcursor = mx;
mdb_xcursor_init0(mc);
} else {
mc->mc_xcursor = NULL;
}
}
int
mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
{
MDB_cursor *mc;
MDB_xcursor *mx = NULL;
size_t size = sizeof(MDB_cursor);
if (txn == NULL || ret == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT)
size += sizeof(MDB_xcursor);
if ((mc = malloc(size)) != NULL) {
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
mx = (MDB_xcursor *)(mc + 1);
}
mdb_cursor_init(mc, txn, dbi, mx);
} else {
return ENOMEM;
}
*ret = mc;
return MDB_SUCCESS;
}
/* Return the count of duplicate data items for the current key */
int
mdb_cursor_count(MDB_cursor *mc, size_t *countp)
{
MDB_node *leaf;
if (mc == NULL || countp == NULL)
return EINVAL;
if (!(mc->mc_db->md_flags & MDB_DUPSORT))
return EINVAL;
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 != NULL) {
free(mc);
}
}
static int
mdb_update_key(MDB_page *mp, indx_t indx, MDB_val *key)
{
indx_t ptr, i, numkeys;
int delta;
size_t len;
MDB_node *node;
char *base;
DKBUF;
node = NODEPTR(mp, indx);
ptr = mp->mp_ptrs[indx];
DPRINTF("update key %u (ofs %u) [%.*s] to [%s] on page %zu",
indx, ptr,
(int)node->mn_ksize, (char *)NODEKEY(node),
DKEY(key),
mp->mp_pgno);
delta = key->mv_size - node->mn_ksize;
if (delta) {
if (delta > 0 && SIZELEFT(mp) < delta) {
DPRINTF("OUCH! Not enough room, delta = %d", delta);
return ENOSPC;
}
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;
len = ptr - mp->mp_upper + NODESIZE;
memmove(base - delta, base, len);
mp->mp_upper -= delta;
node = NODEPTR(mp, indx);
node->mn_ksize = key->mv_size;
}
memcpy(NODEKEY(node), key->mv_data, key->mv_size);
return MDB_SUCCESS;
}
/* Move a node from csrc to cdst.
*/
static int
mdb_move_node(MDB_cursor *csrc, MDB_cursor *cdst)
{
int rc;
MDB_node *srcnode;
MDB_val key, data;
DKBUF;
/* Mark src and dst as dirty. */
if ((rc = mdb_touch(csrc)) ||
(rc = mdb_touch(cdst)))
return rc;
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0); /* fake */
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;
} else {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
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 */
mdb_search_page_root(csrc, NULL, 0);
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);
}
DPRINTF("moving %s node %u [%s] on page %zu to node %u on page %zu",
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_add_node(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, NODEPGNO(srcnode),
srcnode->mn_flags);
if (rc != MDB_SUCCESS)
return rc;
/* Delete the node from the source page.
*/
mdb_del_node(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
/* 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 %zu to [%s]",
csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key));
if ((rc = mdb_update_key(csrc->mc_pg[csrc->mc_top-1], csrc->mc_ki[csrc->mc_top-1],
&key)) != MDB_SUCCESS)
return rc;
}
if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
MDB_val nullkey;
nullkey.mv_size = 0;
assert(mdb_update_key(csrc->mc_pg[csrc->mc_top], 0, &nullkey) == 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 %zu to [%s]",
cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key));
if ((rc = mdb_update_key(cdst->mc_pg[cdst->mc_top-1], cdst->mc_ki[cdst->mc_top-1],
&key)) != MDB_SUCCESS)
return rc;
}
if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
MDB_val nullkey;
nullkey.mv_size = 0;
assert(mdb_update_key(cdst->mc_pg[cdst->mc_top], 0, &nullkey) == MDB_SUCCESS);
}
}
return MDB_SUCCESS;
}
static int
mdb_merge(MDB_cursor *csrc, MDB_cursor *cdst)
{
int rc;
indx_t i, j;
MDB_node *srcnode;
MDB_val key, data;
DPRINTF("merging page %zu into %zu", csrc->mc_pg[csrc->mc_top]->mp_pgno,
cdst->mc_pg[cdst->mc_top]->mp_pgno);
assert(csrc->mc_snum > 1); /* can't merge root page */
assert(cdst->mc_snum > 1);
/* Mark dst as dirty. */
if ((rc = mdb_touch(cdst)))
return rc;
/* Move all nodes from src to dst.
*/
j = NUMKEYS(cdst->mc_pg[cdst->mc_top]);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = METADATA(csrc->mc_pg[csrc->mc_top]);
for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
rc = mdb_add_node(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(csrc->mc_pg[csrc->mc_top]); i++, j++) {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], i);
key.mv_size = srcnode->mn_ksize;
key.mv_data = NODEKEY(srcnode);
data.mv_size = NODEDSZ(srcnode);
data.mv_data = NODEDATA(srcnode);
rc = mdb_add_node(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
if (rc != MDB_SUCCESS)
return rc;
}
}
DPRINTF("dst page %zu now has %u keys (%.1f%% filled)",
cdst->mc_pg[cdst->mc_top]->mp_pgno, NUMKEYS(cdst->mc_pg[cdst->mc_top]), (float)PAGEFILL(cdst->mc_txn->mt_env, cdst->mc_pg[cdst->mc_top]) / 10);
/* Unlink the src page from parent and add to free list.
*/
mdb_del_node(csrc->mc_pg[csrc->mc_top-1], csrc->mc_ki[csrc->mc_top-1], 0);
if (csrc->mc_ki[csrc->mc_top-1] == 0) {
key.mv_size = 0;
if ((rc = mdb_update_key(csrc->mc_pg[csrc->mc_top-1], 0, &key)) != MDB_SUCCESS)
return rc;
}
mdb_midl_append(csrc->mc_txn->mt_free_pgs, csrc->mc_pg[csrc->mc_top]->mp_pgno);
if (IS_LEAF(csrc->mc_pg[csrc->mc_top]))
csrc->mc_db->md_leaf_pages--;
else
csrc->mc_db->md_branch_pages--;
cursor_pop_page(csrc);
return mdb_rebalance(csrc);
}
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;
for (i=0; i<csrc->mc_snum; i++) {
cdst->mc_pg[i] = csrc->mc_pg[i];
cdst->mc_ki[i] = csrc->mc_ki[i];
}
}
static int
mdb_rebalance(MDB_cursor *mc)
{
MDB_node *node;
int rc;
unsigned int ptop;
MDB_cursor mn;
DPRINTF("rebalancing %s page %zu (has %u keys, %.1f%% full)",
IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
mc->mc_pg[mc->mc_top]->mp_pgno, 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]) >= FILL_THRESHOLD) {
DPRINTF("no need to rebalance page %zu, above fill threshold",
mc->mc_pg[mc->mc_top]->mp_pgno);
return MDB_SUCCESS;
}
if (mc->mc_snum < 2) {
if (NUMKEYS(mc->mc_pg[mc->mc_top]) == 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;
mdb_midl_append(mc->mc_txn->mt_free_pgs, mc->mc_pg[mc->mc_top]->mp_pgno);
mc->mc_snum = 0;
} else if (IS_BRANCH(mc->mc_pg[mc->mc_top]) && NUMKEYS(mc->mc_pg[mc->mc_top]) == 1) {
DPUTS("collapsing root page!");
mdb_midl_append(mc->mc_txn->mt_free_pgs, mc->mc_pg[mc->mc_top]->mp_pgno);
mc->mc_db->md_root = NODEPGNO(NODEPTR(mc->mc_pg[mc->mc_top], 0));
if ((rc = mdb_get_page(mc->mc_txn, mc->mc_db->md_root,
&mc->mc_pg[mc->mc_top])))
return rc;
mc->mc_db->md_depth--;
mc->mc_db->md_branch_pages--;
} 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;
assert(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;
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]);
if ((rc = mdb_get_page(mc->mc_txn, NODEPGNO(node), &mn.mc_pg[mn.mc_top])))
return rc;
mn.mc_ki[mn.mc_top] = 0;
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
} 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]);
if ((rc = mdb_get_page(mc->mc_txn, NODEPGNO(node), &mn.mc_pg[mn.mc_top])))
return rc;
mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
mc->mc_ki[mc->mc_top] = 0;
}
DPRINTF("found neighbor page %zu (%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 at least two
* keys, move one key from it.
*
* Otherwise we should try to merge them.
*/
if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= FILL_THRESHOLD && NUMKEYS(mn.mc_pg[mn.mc_top]) >= 2)
return mdb_move_node(&mn, mc);
else { /* FIXME: if (has_enough_room()) */
if (mc->mc_ki[ptop] == 0)
return mdb_merge(&mn, mc);
else
return mdb_merge(mc, &mn);
}
}
static int
mdb_del0(MDB_cursor *mc, MDB_node *leaf)
{
int rc;
/* add overflow pages to free list */
if (!IS_LEAF2(mc->mc_pg[mc->mc_top]) && F_ISSET(leaf->mn_flags, F_BIGDATA)) {
int i, ovpages;
pgno_t pg;
memcpy(&pg, NODEDATA(leaf), sizeof(pg));
ovpages = OVPAGES(NODEDSZ(leaf), mc->mc_txn->mt_env->me_psize);
for (i=0; i<ovpages; i++) {
DPRINTF("freed ov page %zu", pg);
mdb_midl_append(mc->mc_txn->mt_free_pgs, pg);
pg++;
}
}
mdb_del_node(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], mc->mc_db->md_pad);
mc->mc_db->md_entries--;
rc = mdb_rebalance(mc);
if (rc != MDB_SUCCESS)
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)
{
MDB_cursor mc;
MDB_xcursor mx;
MDB_cursor_op op;
MDB_val rdata, *xdata;
int rc, exact;
DKBUF;
assert(key != NULL);
DPRINTF("====> delete db %u key [%s]", dbi, DKEY(key));
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
return EACCES;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
mdb_cursor_init(&mc, txn, dbi, &mx);
exact = 0;
if (data) {
op = MDB_GET_BOTH;
rdata = *data;
xdata = &rdata;
} else {
op = MDB_SET;
xdata = NULL;
}
rc = mdb_cursor_set(&mc, key, xdata, op, &exact);
if (rc == 0)
rc = mdb_cursor_del(&mc, data ? 0 : MDB_NODUPDATA);
return rc;
}
/* Split page <mc->top>, and insert <key,(data|newpgno)> in either left or
* right sibling, at index <mc->ki> (as if unsplit). Updates mc->top and
* mc->ki with the actual values after split, ie if mc->top and mc->ki
* refer to a node in the new right sibling page.
*/
static int
mdb_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno)
{
uint8_t flags;
int rc = MDB_SUCCESS, ins_new = 0;
indx_t newindx;
pgno_t pgno = 0;
unsigned int i, j, split_indx, nkeys, pmax;
MDB_node *node;
MDB_val sepkey, rkey, rdata;
MDB_page *copy;
MDB_page *mp, *rp, *pp;
unsigned int ptop;
MDB_cursor mn;
DKBUF;
mp = mc->mc_pg[mc->mc_top];
newindx = mc->mc_ki[mc->mc_top];
DPRINTF("-----> splitting %s page %zu and adding [%s] at index %i",
IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
DKEY(newkey), mc->mc_ki[mc->mc_top]);
if (mc->mc_snum < 2) {
if ((pp = mdb_new_page(mc, P_BRANCH, 1)) == NULL)
return ENOMEM;
/* shift current top to make room for new parent */
mc->mc_pg[1] = mc->mc_pg[0];
mc->mc_ki[1] = mc->mc_ki[0];
mc->mc_pg[0] = pp;
mc->mc_ki[0] = 0;
mc->mc_db->md_root = pp->mp_pgno;
DPRINTF("root split! new root = %zu", pp->mp_pgno);
mc->mc_db->md_depth++;
/* Add left (implicit) pointer. */
if ((rc = mdb_add_node(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--;
return rc;
}
mc->mc_snum = 2;
mc->mc_top = 1;
ptop = 0;
} else {
ptop = mc->mc_top-1;
DPRINTF("parent branch page is %zu", mc->mc_pg[ptop]->mp_pgno);
}
/* Create a right sibling. */
if ((rp = mdb_new_page(mc, mp->mp_flags, 1)) == NULL)
return ENOMEM;
mdb_cursor_copy(mc, &mn);
mn.mc_pg[mn.mc_top] = rp;
mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
DPRINTF("new right sibling: page %zu", rp->mp_pgno);
nkeys = NUMKEYS(mp);
split_indx = nkeys / 2 + 1;
if (IS_LEAF2(rp)) {
char *split, *ins;
int x;
unsigned int lsize, rsize, ksize;
/* Move half of the keys to the right sibling */
copy = NULL;
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;
mc->mc_pg[mc->mc_top] = rp;
}
goto newsep;
}
/* For leaf pages, check the split point based on what
* fits where, since otherwise add_node can fail.
*/
if (IS_LEAF(mp)) {
unsigned int psize, nsize;
/* Maximum free space in an empty page */
pmax = mc->mc_txn->mt_env->me_psize - PAGEHDRSZ;
nsize = mdb_leaf_size(mc->mc_txn->mt_env, newkey, newdata);
if (newindx < split_indx) {
psize = nsize;
for (i=0; i<split_indx; i++) {
node = NODEPTR(mp, i);
psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
if (F_ISSET(node->mn_flags, F_BIGDATA))
psize += sizeof(pgno_t);
else
psize += NODEDSZ(node);
psize += psize & 1;
if (psize > pmax) {
split_indx = i;
break;
}
}
} else {
psize = nsize;
for (i=nkeys-1; i>=split_indx; i--) {
node = NODEPTR(mp, i);
psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
if (F_ISSET(node->mn_flags, F_BIGDATA))
psize += sizeof(pgno_t);
else
psize += NODEDSZ(node);
psize += psize & 1;
if (psize > pmax) {
split_indx = i+1;
break;
}
}
}
}
/* First find the separating key between the split pages.
*/
if (newindx == split_indx) {
sepkey.mv_size = newkey->mv_size;
sepkey.mv_data = newkey->mv_data;
} else {
node = NODEPTR(mp, split_indx);
sepkey.mv_size = node->mn_ksize;
sepkey.mv_data = NODEKEY(node);
}
newsep:
DPRINTF("separator is [%s]", DKEY(&sepkey));
/* Copy separator key to the parent.
*/
if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(mc->mc_txn->mt_env, &sepkey)) {
mn.mc_snum--;
mn.mc_top--;
rc = mdb_split(&mn, &sepkey, NULL, rp->mp_pgno);
/* 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])) {
mc->mc_pg[ptop] = mn.mc_pg[ptop];
mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
}
} else {
mn.mc_top--;
rc = mdb_add_node(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
mn.mc_top++;
}
if (IS_LEAF2(rp)) {
return rc;
}
if (rc != MDB_SUCCESS) {
return rc;
}
/* Move half of the keys to the right sibling. */
/* grab a page to hold a temporary copy */
if (mc->mc_txn->mt_env->me_dpages) {
copy = mc->mc_txn->mt_env->me_dpages;
mc->mc_txn->mt_env->me_dpages = copy->mp_next;
} else {
if ((copy = malloc(mc->mc_txn->mt_env->me_psize)) == NULL)
return ENOMEM;
}
copy->mp_pgno = mp->mp_pgno;
copy->mp_flags = mp->mp_flags;
copy->mp_lower = PAGEHDRSZ;
copy->mp_upper = mc->mc_txn->mt_env->me_psize;
mc->mc_pg[mc->mc_top] = copy;
for (i = j = 0; i <= nkeys; j++) {
if (i == split_indx) {
/* Insert in right sibling. */
/* Reset insert index for right sibling. */
j = (i == newindx && ins_new);
mc->mc_pg[mc->mc_top] = rp;
}
if (i == newindx && !ins_new) {
/* Insert the original entry that caused the split. */
rkey.mv_data = newkey->mv_data;
rkey.mv_size = newkey->mv_size;
if (IS_LEAF(mp)) {
rdata.mv_data = newdata->mv_data;
rdata.mv_size = newdata->mv_size;
} else
pgno = newpgno;
flags = 0;
ins_new = 1;
/* Update page and index for the new key. */
mc->mc_ki[mc->mc_top] = j;
} else if (i == nkeys) {
break;
} else {
node = NODEPTR(mp, i);
rkey.mv_data = NODEKEY(node);
rkey.mv_size = node->mn_ksize;
if (IS_LEAF(mp)) {
rdata.mv_data = NODEDATA(node);
rdata.mv_size = NODEDSZ(node);
} else
pgno = NODEPGNO(node);
flags = node->mn_flags;
i++;
}
if (!IS_LEAF(mp) && j == 0) {
/* First branch index doesn't need key data. */
rkey.mv_size = 0;
}
rc = mdb_add_node(mc, j, &rkey, &rdata, pgno, flags);
}
/* reset back to original page */
if (newindx < split_indx)
mc->mc_pg[mc->mc_top] = mp;
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),
mc->mc_txn->mt_env->me_psize - copy->mp_upper);
/* return tmp page to freelist */
copy->mp_next = mc->mc_txn->mt_env->me_dpages;
mc->mc_txn->mt_env->me_dpages = copy;
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;
assert(key != NULL);
assert(data != NULL);
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
return EACCES;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
if ((flags & (MDB_NOOVERWRITE|MDB_NODUPDATA)) != flags)
return EINVAL;
mdb_cursor_init(&mc, txn, dbi, &mx);
return mdb_cursor_put(&mc, key, data, flags);
}
int
mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
{
/** 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)
if ((flag & CHANGEABLE) != flag)
return EINVAL;
if (onoff)
env->me_flags |= flag;
else
env->me_flags &= ~flag;
return MDB_SUCCESS;
}
int
mdb_env_get_flags(MDB_env *env, unsigned int *arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_flags;
return MDB_SUCCESS;
}
int
mdb_env_get_path(MDB_env *env, const char **arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_path;
return MDB_SUCCESS;
}
static int
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
mdb_env_stat(MDB_env *env, MDB_stat *arg)
{
int toggle;
if (env == NULL || arg == NULL)
return EINVAL;
mdb_env_read_meta(env, &toggle);
return mdb_stat0(env, &env->me_metas[toggle]->mm_dbs[MAIN_DBI], arg);
}
static void
mdb_default_cmp(MDB_txn *txn, MDB_dbi dbi)
{
if (txn->mt_dbs[dbi].md_flags & MDB_REVERSEKEY)
txn->mt_dbxs[dbi].md_cmp = memnrcmp;
else if (txn->mt_dbs[dbi].md_flags & MDB_INTEGERKEY)
txn->mt_dbxs[dbi].md_cmp = cintcmp;
else
txn->mt_dbxs[dbi].md_cmp = memncmp;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
if (txn->mt_dbs[dbi].md_flags & MDB_INTEGERDUP) {
if (txn->mt_dbs[dbi].md_flags & MDB_DUPFIXED)
txn->mt_dbxs[dbi].md_dcmp = intcmp;
else
txn->mt_dbxs[dbi].md_dcmp = cintcmp;
} else if (txn->mt_dbs[dbi].md_flags & MDB_REVERSEDUP) {
txn->mt_dbxs[dbi].md_dcmp = memnrcmp;
} else {
txn->mt_dbxs[dbi].md_dcmp = memncmp;
}
} else {
txn->mt_dbxs[dbi].md_dcmp = NULL;
}
}
int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi)
{
MDB_val key, data;
MDB_dbi i;
int rc, dirty = 0;
size_t len;
if (txn->mt_dbxs[FREE_DBI].md_cmp == NULL) {
mdb_default_cmp(txn, FREE_DBI);
}
/* main DB? */
if (!name) {
*dbi = MAIN_DBI;
if (flags & (MDB_DUPSORT|MDB_REVERSEKEY|MDB_INTEGERKEY))
txn->mt_dbs[MAIN_DBI].md_flags |= (flags & (MDB_DUPSORT|MDB_REVERSEKEY|MDB_INTEGERKEY));
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? */
len = strlen(name);
for (i=2; i<txn->mt_numdbs; i++) {
if (len == txn->mt_dbxs[i].md_name.mv_size &&
!strncmp(name, txn->mt_dbxs[i].md_name.mv_data, len)) {
*dbi = i;
return MDB_SUCCESS;
}
}
if (txn->mt_numdbs >= txn->mt_env->me_maxdbs - 1)
return ENFILE;
/* Find the DB info */
key.mv_size = len;
key.mv_data = (void *)name;
rc = mdb_get(txn, MAIN_DBI, &key, &data);
/* Create if requested */
if (rc == MDB_NOTFOUND && (flags & MDB_CREATE)) {
MDB_cursor mc;
MDB_db dummy;
data.mv_size = sizeof(MDB_db);
data.mv_data = &dummy;
memset(&dummy, 0, sizeof(dummy));
dummy.md_root = P_INVALID;
dummy.md_flags = flags & 0xffff;
mdb_cursor_init(&mc, txn, MAIN_DBI, NULL);
rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA);
dirty = 1;
}
/* OK, got info, add to table */
if (rc == MDB_SUCCESS) {
txn->mt_dbxs[txn->mt_numdbs].md_name.mv_data = strdup(name);
txn->mt_dbxs[txn->mt_numdbs].md_name.mv_size = len;
txn->mt_dbxs[txn->mt_numdbs].md_rel = NULL;
txn->mt_dbxs[txn->mt_numdbs].md_parent = MAIN_DBI;
txn->mt_dbxs[txn->mt_numdbs].md_dirty = dirty;
memcpy(&txn->mt_dbs[txn->mt_numdbs], data.mv_data, sizeof(MDB_db));
*dbi = txn->mt_numdbs;
txn->mt_env->me_dbs[0][txn->mt_numdbs] = txn->mt_dbs[txn->mt_numdbs];
txn->mt_env->me_dbs[1][txn->mt_numdbs] = txn->mt_dbs[txn->mt_numdbs];
mdb_default_cmp(txn, txn->mt_numdbs);
txn->mt_numdbs++;
}
return rc;
}
int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg)
{
if (txn == NULL || arg == NULL || dbi >= txn->mt_numdbs)
return EINVAL;
return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg);
}
void mdb_close(MDB_txn *txn, MDB_dbi dbi)
{
char *ptr;
if (dbi <= MAIN_DBI || dbi >= txn->mt_numdbs)
return;
ptr = txn->mt_dbxs[dbi].md_name.mv_data;
txn->mt_dbxs[dbi].md_name.mv_data = NULL;
txn->mt_dbxs[dbi].md_name.mv_size = 0;
free(ptr);
}
int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp)
{
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
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 == NULL || !dbi || dbi >= txn->mt_numdbs)
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 == NULL || !dbi || dbi >= txn->mt_numdbs)
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 == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
txn->mt_dbxs[dbi].md_relctx = ctx;
return MDB_SUCCESS;
}
/** @} */