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lmdb/libraries/libmdb/mdb.c

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/* mdb.c - memory-mapped database library */
/*
* 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/queue.h>
#include <sys/param.h>
#include <sys/uio.h>
#include <sys/mman.h>
#ifdef HAVE_SYS_FILE_H
#include <sys/file.h>
#endif
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <pthread.h>
#include "mdb.h"
#define ULONG unsigned long
typedef ULONG pgno_t;
#include "midl.h"
#ifndef DEBUG
#define DEBUG 1
#endif
#if DEBUG && defined(__GNUC__)
# define DPRINTF(fmt, ...) \
fprintf(stderr, "%s:%d: " fmt "\n", __func__, __LINE__, ##__VA_ARGS__)
#else
# define DPRINTF(...) ((void) 0)
#endif
#define PAGESIZE 4096
#define MDB_MINKEYS 4
#define MDB_MAGIC 0xBEEFC0DE
#define MDB_VERSION 1
#define MAXKEYSIZE 511
#define P_INVALID (~0UL)
#define F_ISSET(w, f) (((w) & (f)) == (f))
typedef uint16_t indx_t;
#define DEFAULT_READERS 126
#define DEFAULT_MAPSIZE 1048576
/* Lock descriptor stuff */
#ifndef CACHELINE
#define CACHELINE 64 /* most CPUs. Itanium uses 128 */
#endif
typedef struct MDB_rxbody {
ULONG mrb_txnid;
pid_t mrb_pid;
pthread_t mrb_tid;
} MDB_rxbody;
typedef struct MDB_reader {
union {
MDB_rxbody mrx;
#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;
typedef struct MDB_txbody {
uint32_t mtb_magic;
uint32_t mtb_version;
pthread_mutex_t mtb_mutex;
ULONG mtb_txnid;
uint32_t mtb_numreaders;
uint32_t mtb_me_toggle;
} MDB_txbody;
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_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 {
pthread_mutex_t mt2_wmutex;
#define mti_wmutex mt2.mt2_wmutex
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 { /* represents a page of storage */
#define mp_pgno mp_p.p_pgno
union padded {
pgno_t p_pgno; /* page number */
void * p_align; /* for IL32P64 */
} 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 /* DB with small, fixed size keys and no data */
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 */
struct {
indx_t pb_ksize; /* on a LEAF2 page */
indx_t pb_numkeys;
} pb2;
} mp_pb;
indx_t mp_ptrs[1]; /* dynamic size */
} MDB_page;
#define PAGEHDRSZ ((unsigned) offsetof(MDB_page, mp_ptrs))
#define NUMKEYS(p) (((p)->mp_lower - PAGEHDRSZ) >> 1)
#define SIZELEFT(p) (indx_t)((p)->mp_upper - (p)->mp_lower)
#define PAGEFILL(env, p) (1000L * ((env)->me_psize - PAGEHDRSZ - SIZELEFT(p)) / \
((env)->me_psize - PAGEHDRSZ))
#define IS_LEAF(p) F_ISSET((p)->mp_flags, P_LEAF)
#define IS_BRANCH(p) F_ISSET((p)->mp_flags, P_BRANCH)
#define IS_OVERFLOW(p) F_ISSET((p)->mp_flags, P_OVERFLOW)
#define OVPAGES(size, psize) (PAGEHDRSZ + size + psize - 1) / psize;
typedef struct MDB_db {
uint32_t md_pad;
uint16_t md_flags;
uint16_t md_depth;
ULONG md_branch_pages;
ULONG md_leaf_pages;
ULONG md_overflow_pages;
ULONG md_entries;
pgno_t md_root;
} MDB_db;
#define FREE_DBI 0
#define MAIN_DBI 1
typedef struct MDB_meta { /* meta (footer) page content */
uint32_t mm_magic;
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 */
#define mm_psize mm_dbs[0].md_pad
#define mm_flags mm_dbs[0].md_flags
pgno_t mm_last_pg; /* last used page in file */
ULONG mm_txnid; /* txnid that committed this page */
} MDB_meta;
typedef struct MDB_dhead { /* a dirty page */
MDB_page *md_parent;
unsigned md_pi; /* parent index */
int md_num;
} MDB_dhead;
typedef struct MDB_dpage {
MDB_dhead h;
MDB_page p;
} MDB_dpage;
typedef struct MDB_oldpages {
struct MDB_oldpages *mo_next;
ULONG mo_txnid;
pgno_t mo_pages[1]; /* dynamic */
} MDB_oldpages;
typedef struct MDB_pageparent {
MDB_page *mp_page;
MDB_page *mp_parent;
unsigned mp_pi;
} MDB_pageparent;
static MDB_dpage *mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num);
static int mdb_touch(MDB_txn *txn, MDB_pageparent *mp);
typedef struct MDB_ppage { /* ordered list of pages */
SLIST_ENTRY(MDB_ppage) mp_entry;
MDB_page *mp_page;
unsigned int mp_ki; /* cursor index on page */
} MDB_ppage;
SLIST_HEAD(page_stack, MDB_ppage);
/* FIXME: tree depth is mostly bounded, we should just
* use a fixed array and avoid malloc/pointer chasing
*/
#define CURSOR_EMPTY(c) SLIST_EMPTY(&(c)->mc_stack)
#define CURSOR_TOP(c) SLIST_FIRST(&(c)->mc_stack)
#define CURSOR_POP(c) SLIST_REMOVE_HEAD(&(c)->mc_stack, mp_entry)
#define CURSOR_PUSH(c,p) SLIST_INSERT_HEAD(&(c)->mc_stack, p, mp_entry)
struct MDB_xcursor;
struct MDB_cursor {
MDB_txn *mc_txn;
struct page_stack mc_stack; /* stack of parent pages */
MDB_dbi mc_dbi;
short mc_initialized; /* 1 if initialized */
short mc_eof; /* 1 if end is reached */
struct MDB_xcursor *mc_xcursor;
};
#define METADATA(p) ((void *)((char *)p + PAGEHDRSZ))
typedef struct MDB_node {
#define mn_pgno mn_p.np_pgno
#define mn_dsize mn_p.np_dsize
union {
pgno_t np_pgno; /* child page number */
uint32_t np_dsize; /* leaf data size */
} mn_p;
unsigned int mn_flags:4;
unsigned int mn_ksize:12; /* key size */
#define F_BIGDATA 0x01 /* data put on overflow page */
#define F_SUBDATA 0x02 /* data is a sub-database */
char mn_data[1];
} MDB_node;
typedef struct MDB_dbx {
MDB_val md_name;
MDB_cmp_func *md_cmp; /* user compare function */
MDB_cmp_func *md_dcmp; /* user dupsort function */
MDB_rel_func *md_rel; /* user relocate function */
MDB_dbi md_parent;
unsigned int md_dirty;
} MDB_dbx;
struct MDB_txn {
pgno_t mt_next_pgno; /* next unallocated page */
ULONG mt_txnid;
ULONG mt_oldest;
MDB_env *mt_env;
pgno_t *mt_free_pgs; /* this is an IDL */
union {
MIDL2 *dirty_list; /* modified pages */
MDB_reader *reader;
} mt_u;
MDB_dbx *mt_dbxs; /* array */
MDB_db *mt_dbs;
unsigned int mt_numdbs;
#define MDB_TXN_RDONLY 0x01 /* read-only transaction */
#define MDB_TXN_ERROR 0x02 /* an error has occurred */
#define MDB_TXN_METOGGLE 0x04 /* used meta page 1 */
unsigned int mt_flags;
};
/* Context for sorted-dup records */
typedef struct MDB_xcursor {
MDB_cursor mx_cursor;
MDB_txn mx_txn;
MDB_dbx mx_dbxs[4];
MDB_db mx_dbs[4];
} MDB_xcursor;
struct MDB_env {
int me_fd;
int me_lfd;
int me_mfd; /* just for writing the meta pages */
#define MDB_FATAL_ERROR 0x80000000U
uint32_t me_flags;
uint32_t me_extrapad; /* unused for now */
unsigned int me_maxreaders;
unsigned int me_numdbs;
unsigned int me_maxdbs;
char *me_path;
char *me_map;
MDB_txninfo *me_txns;
MDB_meta *me_metas[2];
MDB_meta *me_meta;
MDB_txn *me_txn; /* current write transaction */
size_t me_mapsize;
off_t me_size; /* current file size */
pgno_t me_maxpg; /* me_mapsize / me_psize */
unsigned int me_psize;
unsigned int me_db_toggle;
MDB_dbx *me_dbxs; /* array */
MDB_db *me_dbs[2];
MDB_oldpages *me_pghead;
pthread_key_t me_txkey; /* thread-key for readers */
pgno_t me_free_pgs[MDB_IDL_UM_SIZE];
MIDL2 me_dirty_list[MDB_IDL_DB_SIZE];
};
#define NODESIZE offsetof(MDB_node, mn_data)
#define INDXSIZE(k) (NODESIZE + ((k) == NULL ? 0 : (k)->mv_size))
#define LEAFSIZE(k, d) (NODESIZE + (k)->mv_size + (d)->mv_size)
#define NODEPTR(p, i) ((MDB_node *)((char *)(p) + (p)->mp_ptrs[i]))
#define NODEKEY(node) (void *)((node)->mn_data)
#define NODEDATA(node) (void *)((char *)(node)->mn_data + (node)->mn_ksize)
#define NODEPGNO(node) ((node)->mn_pgno)
#define NODEDSZ(node) ((node)->mn_dsize)
#define MDB_COMMIT_PAGES 64 /* max number of pages to write in one commit */
static int mdb_search_page_root(MDB_txn *txn,
MDB_dbi dbi, MDB_val *key,
MDB_cursor *cursor, int modify,
MDB_pageparent *mpp);
static int mdb_search_page(MDB_txn *txn,
MDB_dbi dbi, MDB_val *key,
MDB_cursor *cursor, int modify,
MDB_pageparent *mpp);
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 MDB_page *mdb_get_page(MDB_txn *txn, pgno_t pgno);
static MDB_node *mdb_search_node(MDB_txn *txn, MDB_dbi dbi, MDB_page *mp,
MDB_val *key, int *exactp, unsigned int *kip);
static int mdb_add_node(MDB_txn *txn, MDB_dbi dbi, MDB_page *mp,
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);
static int mdb_del0(MDB_txn *txn, MDB_dbi dbi, unsigned int ki,
MDB_pageparent *mpp, MDB_node *leaf);
static int mdb_put0(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data, unsigned int flags);
static int mdb_read_data(MDB_txn *txn, MDB_node *leaf, MDB_val *data);
static int mdb_rebalance(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *mp);
static int mdb_update_key(MDB_page *mp, indx_t indx, MDB_val *key);
static int mdb_move_node(MDB_txn *txn, MDB_dbi dbi,
MDB_pageparent *src, indx_t srcindx,
MDB_pageparent *dst, indx_t dstindx);
static int mdb_merge(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *src,
MDB_pageparent *dst);
static int mdb_split(MDB_txn *txn, MDB_dbi dbi, MDB_page **mpp,
unsigned int *newindxp, MDB_val *newkey,
MDB_val *newdata, pgno_t newpgno);
static MDB_dpage *mdb_new_page(MDB_txn *txn, MDB_dbi dbi, uint32_t flags, int num);
static void cursor_pop_page(MDB_cursor *cursor);
static MDB_ppage *cursor_push_page(MDB_cursor *cursor,
MDB_page *mp);
static int mdb_set_key(MDB_node *node, MDB_val *key);
static int mdb_sibling(MDB_cursor *cursor, int move_right);
static int mdb_cursor_next(MDB_cursor *cursor,
MDB_val *key, MDB_val *data, MDB_cursor_op op);
static int mdb_cursor_prev(MDB_cursor *cursor,
MDB_val *key, MDB_val *data, MDB_cursor_op op);
static int mdb_cursor_set(MDB_cursor *cursor,
MDB_val *key, MDB_val *data, MDB_cursor_op op, int *exactp);
static int mdb_cursor_first(MDB_cursor *cursor,
MDB_val *key, MDB_val *data);
static int mdb_cursor_last(MDB_cursor *cursor,
MDB_val *key, MDB_val *data);
static void mdb_xcursor_init0(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
static void mdb_xcursor_init1(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx, MDB_node *node);
static void mdb_xcursor_fini(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx);
static size_t mdb_leaf_size(MDB_env *env, MDB_val *key,
MDB_val *data);
static size_t mdb_branch_size(MDB_env *env, MDB_val *key);
static int memncmp(const void *s1, size_t n1,
const void *s2, size_t n2);
static int memnrcmp(const void *s1, size_t n1,
const void *s2, size_t n2);
static int
memncmp(const void *s1, size_t n1, const void *s2, size_t n2)
{
int diff, len_diff = -1;
if (n1 >= n2) {
len_diff = (n1 > n2);
n1 = n2;
}
diff = memcmp(s1, s2, n1);
return diff ? diff : len_diff;
}
static int
memnrcmp(const void *s1, size_t n1, const void *s2, size_t n2)
{
const unsigned char *p1, *p2, *p1_lim;
if (n2 == 0)
return n1 != 0;
if (n1 == 0)
return -1;
p1 = (const unsigned char *)s1 + n1 - 1;
p2 = (const unsigned char *)s2 + n2 - 1;
for (p1_lim = (n1 <= n2 ? s1 : s2); *p1 == *p2; p1--, p2--) {
if (p1 == p1_lim)
return (p1 != s1) ? (p1 != p2) : (p2 != s2) ? -1 : 0;
}
return *p1 - *p2;
}
char *
mdb_version(int *maj, int *min, int *pat)
{
*maj = MDB_VERSION_MAJOR;
*min = MDB_VERSION_MINOR;
*pat = MDB_VERSION_PATCH;
return MDB_VERSION_STRING;
}
static const char *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 (char *)errstr[err - MDB_KEYEXIST];
return strerror(err);
}
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);
}
static int
_mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *key1, const MDB_val *key2)
{
if (txn->mt_dbs[dbi].md_flags & (MDB_REVERSEKEY
#if __BYTE_ORDER == __LITTLE_ENDIAN
|MDB_INTEGERKEY
#endif
))
return memnrcmp(key1->mv_data, key1->mv_size, key2->mv_data, key2->mv_size);
else
return memncmp((char *)key1->mv_data, key1->mv_size, key2->mv_data, key2->mv_size);
}
/* Allocate new page(s) for writing */
static MDB_dpage *
mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num)
{
MDB_dpage *dp;
pgno_t pgno = P_INVALID;
ULONG oldest;
MIDL2 mid;
if (txn->mt_txnid > 2) {
oldest = txn->mt_txnid - 2;
if (!txn->mt_env->me_pghead && txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
/* See if there's anything in the free DB */
MDB_pageparent mpp;
MDB_node *leaf;
ULONG *kptr;
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
mdb_search_page(txn, FREE_DBI, NULL, NULL, 0, &mpp);
leaf = NODEPTR(mpp.mp_page, 0);
kptr = (ULONG *)NODEKEY(leaf);
/* It's potentially usable, unless there are still
* older readers outstanding. Grab it.
*/
if (oldest > *kptr) {
MDB_oldpages *mop;
MDB_val data;
pgno_t *idl;
mdb_read_data(txn, leaf, &data);
idl = (ULONG *)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 %lu root %lu num %lu",
mop->mo_txnid, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
for (i=0; i<idl[0]; i++) {
DPRINTF("IDL %lu", idl[i+1]);
}
}
#endif
/* drop this IDL from the DB */
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
mdb_search_page(txn, FREE_DBI, NULL, NULL, 1, &mpp);
leaf = NODEPTR(mpp.mp_page, 0);
mdb_del0(txn, FREE_DBI, 0, &mpp, leaf);
}
}
if (txn->mt_env->me_pghead) {
unsigned int i;
for (i=0; i<txn->mt_env->me_txns->mti_numreaders; i++) {
ULONG mr = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
if (!mr) continue;
if (mr < oldest)
oldest = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
}
if (oldest > txn->mt_env->me_pghead->mo_txnid) {
MDB_oldpages *mop = txn->mt_env->me_pghead;
txn->mt_oldest = oldest;
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)
return NULL;
}
if ((dp = malloc(txn->mt_env->me_psize * num + sizeof(MDB_dhead))) == NULL)
return NULL;
dp->h.md_num = num;
dp->h.md_parent = parent;
dp->h.md_pi = parent_idx;
if (pgno == P_INVALID) {
dp->p.mp_pgno = txn->mt_next_pgno;
txn->mt_next_pgno += num;
} else {
dp->p.mp_pgno = pgno;
}
mid.mid = dp->p.mp_pgno;
mid.mptr = dp;
mdb_midl2_insert(txn->mt_u.dirty_list, &mid);
return dp;
}
/* Touch a page: make it dirty and re-insert into tree with updated pgno.
*/
static int
mdb_touch(MDB_txn *txn, MDB_pageparent *pp)
{
MDB_page *mp = pp->mp_page;
pgno_t pgno;
assert(txn != NULL);
assert(pp != NULL);
if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
MDB_dpage *dp;
if ((dp = mdb_alloc_page(txn, pp->mp_parent, pp->mp_pi, 1)) == NULL)
return ENOMEM;
DPRINTF("touched page %lu -> %lu", mp->mp_pgno, dp->p.mp_pgno);
mdb_midl_insert(txn->mt_free_pgs, mp->mp_pgno);
pgno = dp->p.mp_pgno;
memcpy(&dp->p, mp, txn->mt_env->me_psize);
mp = &dp->p;
mp->mp_pgno = pgno;
mp->mp_flags |= P_DIRTY;
/* Update the page number to new touched page. */
if (pp->mp_parent != NULL)
NODEPGNO(NODEPTR(pp->mp_parent, pp->mp_pi)) = mp->mp_pgno;
pp->mp_page = mp;
}
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 = errno;
}
return rc;
}
int
mdb_txn_begin(MDB_env *env, int rdonly, MDB_txn **ret)
{
MDB_txn *txn;
int rc, toggle;
if (env->me_flags & MDB_FATAL_ERROR) {
DPRINTF("mdb_txn_begin: environment had fatal error, must shutdown!");
return MDB_PANIC;
}
if ((txn = calloc(1, sizeof(MDB_txn))) == NULL) {
DPRINTF("calloc: %s", strerror(errno));
return ENOMEM;
}
if (rdonly) {
txn->mt_flags |= MDB_TXN_RDONLY;
} else {
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;
pthread_mutex_lock(&env->me_txns->mti_wmutex);
env->me_txns->mti_txnid++;
}
txn->mt_txnid = env->me_txns->mti_txnid;
if (rdonly) {
MDB_reader *r = pthread_getspecific(env->me_txkey);
if (!r) {
unsigned int i;
pthread_mutex_lock(&env->me_txns->mti_mutex);
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) {
pthread_mutex_unlock(&env->me_txns->mti_mutex);
return ENOSPC;
}
env->me_txns->mti_readers[i].mr_pid = getpid();
env->me_txns->mti_readers[i].mr_tid = pthread_self();
r = &env->me_txns->mti_readers[i];
pthread_setspecific(env->me_txkey, r);
if (i >= env->me_txns->mti_numreaders)
env->me_txns->mti_numreaders = i+1;
pthread_mutex_unlock(&env->me_txns->mti_mutex);
}
r->mr_txnid = txn->mt_txnid;
txn->mt_u.reader = r;
} else {
env->me_txn = txn;
}
txn->mt_env = env;
toggle = env->me_txns->mti_me_toggle;
if ((rc = mdb_env_read_meta(env, &toggle)) != MDB_SUCCESS) {
mdb_txn_abort(txn);
return rc;
}
/* Copy the DB arrays */
txn->mt_numdbs = env->me_numdbs;
txn->mt_dbxs = env->me_dbxs; /* mostly static anyway */
txn->mt_dbs = malloc(env->me_maxdbs * sizeof(MDB_db));
memcpy(txn->mt_dbs, env->me_meta->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));
if (!rdonly) {
if (toggle)
txn->mt_flags |= MDB_TXN_METOGGLE;
txn->mt_next_pgno = env->me_meta->mm_last_pg+1;
}
DPRINTF("begin transaction %lu on mdbenv %p, root page %lu",
txn->mt_txnid, (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
*ret = txn;
return MDB_SUCCESS;
}
void
mdb_txn_abort(MDB_txn *txn)
{
MDB_env *env;
if (txn == NULL)
return;
env = txn->mt_env;
DPRINTF("abort transaction %lu on mdbenv %p, root page %lu",
txn->mt_txnid, (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
free(txn->mt_dbs);
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
txn->mt_u.reader->mr_txnid = 0;
} else {
MDB_oldpages *mop;
unsigned int i;
/* Discard all dirty pages. */
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++)
free(txn->mt_u.dirty_list[i].mptr);
while ((mop = txn->mt_env->me_pghead)) {
txn->mt_env->me_pghead = mop->mo_next;
free(mop);
}
env->me_txn = NULL;
env->me_txns->mti_txnid--;
for (i=2; i<env->me_numdbs; i++)
env->me_dbxs[i].md_dirty = 0;
pthread_mutex_unlock(&env->me_txns->mti_wmutex);
}
free(txn);
}
int
mdb_txn_commit(MDB_txn *txn)
{
int n, done;
unsigned int i;
ssize_t rc;
off_t size;
MDB_dpage *dp;
MDB_env *env;
pgno_t next;
struct iovec iov[MDB_COMMIT_PAGES];
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) {
DPRINTF("attempt to commit unknown transaction");
mdb_txn_abort(txn);
return EINVAL;
}
if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
DPRINTF("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 transaction %lu on mdbenv %p, root page %lu",
txn->mt_txnid, (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
/* 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 = (char *)&mop->mo_txnid;
data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
data.mv_data = mop->mo_pages;
mdb_put0(txn, FREE_DBI, &key, &data, 0);
free(env->me_pghead);
env->me_pghead = NULL;
}
/* save to free list */
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
MDB_val key, data;
MDB_pageparent mpp;
/* make sure last page of freeDB is touched and on freelist */
key.mv_size = MAXKEYSIZE+1;
key.mv_data = NULL;
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
mdb_search_page(txn, FREE_DBI, &key, NULL, 1, &mpp);
#if DEBUG > 1
{
unsigned int i;
ULONG *idl = txn->mt_free_pgs;
DPRINTF("IDL write txn %lu root %lu num %lu",
txn->mt_txnid, txn->mt_dbs[FREE_DBI].md_root, idl[0]);
for (i=0; i<idl[0]; i++) {
DPRINTF("IDL %lu", idl[i+1]);
}
}
#endif
/* write to last page of freeDB */
key.mv_size = sizeof(pgno_t);
key.mv_data = (char *)&txn->mt_txnid;
data.mv_size = MDB_IDL_SIZEOF(txn->mt_free_pgs);
data.mv_data = txn->mt_free_pgs;
mdb_put0(txn, FREE_DBI, &key, &data, 0);
}
/* Update DB root pointers. Their pages have already been
* touched so this is all in-place and cannot fail.
*/
{
MDB_val data;
data.mv_size = sizeof(MDB_db);
for (i = 2; i < txn->mt_numdbs; i++) {
if (txn->mt_dbxs[i].md_dirty) {
data.mv_data = &txn->mt_dbs[i];
mdb_put0(txn, MAIN_DBI, &txn->mt_dbxs[i].md_name, &data, 0);
}
}
}
/* Commit up to MDB_COMMIT_PAGES dirty pages to disk until done.
*/
next = 0;
do {
n = 0;
done = 1;
size = 0;
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++) {
dp = txn->mt_u.dirty_list[i].mptr;
if (dp->p.mp_pgno != next) {
if (n) {
DPRINTF("committing %u dirty pages", n);
rc = writev(env->me_fd, iov, n);
if (rc != size) {
n = errno;
if (rc > 0)
DPRINTF("short write, filesystem full?");
else
DPRINTF("writev: %s", strerror(errno));
mdb_txn_abort(txn);
return n;
}
n = 0;
size = 0;
}
lseek(env->me_fd, dp->p.mp_pgno * env->me_psize, SEEK_SET);
next = dp->p.mp_pgno;
}
DPRINTF("committing page %lu", dp->p.mp_pgno);
iov[n].iov_len = env->me_psize * dp->h.md_num;
iov[n].iov_base = &dp->p;
size += iov[n].iov_len;
next = dp->p.mp_pgno + dp->h.md_num;
/* clear dirty flag */
dp->p.mp_flags &= ~P_DIRTY;
if (++n >= MDB_COMMIT_PAGES) {
done = 0;
break;
}
}
if (n == 0)
break;
DPRINTF("committing %u dirty pages", n);
rc = writev(env->me_fd, iov, n);
if (rc != size) {
n = errno;
if (rc > 0)
DPRINTF("short write, filesystem full?");
else
DPRINTF("writev: %s", strerror(errno));
mdb_txn_abort(txn);
return n;
}
} while (!done);
/* Drop the dirty pages.
*/
for (i=1; i<=txn->mt_u.dirty_list[0].mid; i++)
free(txn->mt_u.dirty_list[i].mptr);
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;
for (i = 2; i < env->me_numdbs; i++) {
if (txn->mt_dbxs[i].md_dirty) {
env->me_dbs[toggle][i] = txn->mt_dbs[i];
txn->mt_dbxs[i].md_dirty = 0;
}
}
for (i = env->me_numdbs; i < txn->mt_numdbs; i++) {
txn->mt_dbxs[i].md_dirty = 0;
env->me_dbxs[i] = txn->mt_dbxs[i];
env->me_dbs[toggle][i] = txn->mt_dbs[i];
}
env->me_db_toggle = toggle;
env->me_numdbs = txn->mt_numdbs;
free(txn->mt_dbs);
}
pthread_mutex_unlock(&env->me_txns->mti_wmutex);
free(txn);
return MDB_SUCCESS;
}
static int
mdb_env_read_header(MDB_env *env, MDB_meta *meta)
{
char page[PAGESIZE];
MDB_page *p;
MDB_meta *m;
int rc;
assert(env != NULL);
/* We don't know the page size yet, so use a minimum value.
*/
if ((rc = pread(env->me_fd, page, PAGESIZE, 0)) == 0) {
return ENOENT;
} else if (rc != PAGESIZE) {
if (rc > 0)
errno = EINVAL;
DPRINTF("read: %s", strerror(errno));
return errno;
}
p = (MDB_page *)page;
if (!F_ISSET(p->mp_flags, P_META)) {
DPRINTF("page %lu not a meta page", p->mp_pgno);
return EINVAL;
}
m = METADATA(p);
if (m->mm_magic != MDB_MAGIC) {
DPRINTF("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;
}
static int
mdb_env_init_meta(MDB_env *env, MDB_meta *meta)
{
MDB_page *p, *q;
MDB_meta *m;
int rc;
unsigned int psize;
DPRINTF("writing new meta page");
psize = sysconf(_SC_PAGE_SIZE);
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));
rc = write(env->me_fd, p, psize * 2);
free(p);
return (rc == (int)psize * 2) ? MDB_SUCCESS : errno;
}
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;
assert(txn != NULL);
assert(txn->mt_env != NULL);
toggle = !F_ISSET(txn->mt_flags, MDB_TXN_METOGGLE);
DPRINTF("writing meta page %d for root page %lu",
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 */
rc = pwrite(env->me_mfd, ptr, len, off);
if (rc != len) {
DPRINTF("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;
rc = pwrite(env->me_fd, ptr, len, off);
env->me_flags |= MDB_FATAL_ERROR;
return errno;
}
txn->mt_env->me_txns->mti_me_toggle = toggle;
return MDB_SUCCESS;
}
static int
mdb_env_read_meta(MDB_env *env, int *which)
{
int toggle = 0;
assert(env != NULL);
if (which)
toggle = *which;
else if (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid)
toggle = 1;
if (env->me_meta != env->me_metas[toggle])
env->me_meta = env->me_metas[toggle];
DPRINTF("Using meta page %d", 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 = -1;
e->me_lfd = -1;
e->me_mfd = -1;
*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, int dbs)
{
env->me_maxdbs = dbs;
return MDB_SUCCESS;
}
int
mdb_env_set_maxreaders(MDB_env *env, int readers)
{
env->me_maxreaders = readers;
return MDB_SUCCESS;
}
int
mdb_env_get_maxreaders(MDB_env *env, int *readers)
{
if (!env || !readers)
return EINVAL;
*readers = env->me_maxreaders;
return MDB_SUCCESS;
}
static int
mdb_env_open2(MDB_env *env, unsigned int flags)
{
int i, newenv = 0;
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;
DPRINTF("new mdbenv");
newenv = 1;
}
if (!env->me_mapsize) {
env->me_mapsize = newenv ? DEFAULT_MAPSIZE : meta.mm_mapsize;
}
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 errno;
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, NULL)) != 0)
return i;
DPRINTF("opened database version %u, pagesize %u",
env->me_meta->mm_version, env->me_psize);
DPRINTF("depth: %u", env->me_meta->mm_dbs[MAIN_DBI].md_depth);
DPRINTF("entries: %lu", env->me_meta->mm_dbs[MAIN_DBI].md_entries);
DPRINTF("branch pages: %lu", env->me_meta->mm_dbs[MAIN_DBI].md_branch_pages);
DPRINTF("leaf pages: %lu", env->me_meta->mm_dbs[MAIN_DBI].md_leaf_pages);
DPRINTF("overflow pages: %lu", env->me_meta->mm_dbs[MAIN_DBI].md_overflow_pages);
DPRINTF("root: %lu", env->me_meta->mm_dbs[MAIN_DBI].md_root);
return MDB_SUCCESS;
}
static void
mdb_env_reader_dest(void *ptr)
{
MDB_reader *reader = ptr;
reader->mr_txnid = 0;
reader->mr_pid = 0;
reader->mr_tid = 0;
}
/* downgrade the exclusive lock on the region back to shared */
static void
mdb_env_share_locks(MDB_env *env)
{
struct flock lock_info;
env->me_txns->mti_txnid = env->me_meta->mm_txnid;
if (env->me_metas[0]->mm_txnid < env->me_metas[1]->mm_txnid)
env->me_txns->mti_me_toggle = 1;
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);
}
static int
mdb_env_setup_locks(MDB_env *env, char *lpath, int mode, int *excl)
{
int rc;
off_t size, rsize;
struct flock lock_info;
*excl = 0;
if ((env->me_lfd = open(lpath, O_RDWR|O_CREAT, mode)) == -1) {
rc = errno;
return rc;
}
/* Try to get exclusive lock. If we succeed, then
* nobody is using the lock region and we should initialize it.
*/
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_SETLK, &lock_info);
if (rc) {
rc = errno;
goto fail;
}
}
size = lseek(env->me_lfd, 0, SEEK_END);
rsize = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
if (size < rsize && *excl) {
if (ftruncate(env->me_lfd, rsize) != 0) {
rc = errno;
goto fail;
}
} else {
rsize = size;
size = rsize - sizeof(MDB_txninfo);
env->me_maxreaders = size/sizeof(MDB_reader) + 1;
}
env->me_txns = mmap(0, rsize, PROT_READ|PROT_WRITE, MAP_SHARED,
env->me_lfd, 0);
if (env->me_txns == MAP_FAILED) {
rc = errno;
goto fail;
}
if (*excl) {
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);
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) {
DPRINTF("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;
}
if (errno != EACCES && errno != EAGAIN) {
rc = errno;
goto fail;
}
}
return MDB_SUCCESS;
fail:
close(env->me_lfd);
env->me_lfd = -1;
return rc;
}
#define LOCKNAME "/lock.mdb"
#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;
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 = errno;
goto leave;
}
if ((rc = mdb_env_open2(env, flags)) == MDB_SUCCESS) {
/* synchronous fd for meta writes */
if (!(flags & (MDB_RDONLY|MDB_NOSYNC)))
oflags |= O_DSYNC;
if ((env->me_mfd = open(dpath, oflags, mode)) == -1) {
rc = errno;
goto leave;
}
env->me_path = strdup(path);
DPRINTF("opened dbenv %p", (void *) env);
pthread_key_create(&env->me_txkey, mdb_env_reader_dest);
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 >= 0) {
close(env->me_fd);
env->me_fd = -1;
}
if (env->me_lfd >= 0) {
close(env->me_lfd);
env->me_lfd = -1;
}
}
free(lpath);
return rc;
}
void
mdb_env_close(MDB_env *env)
{
if (env == NULL)
return;
free(env->me_dbs[1]);
free(env->me_dbs[0]);
free(env->me_dbxs);
free(env->me_path);
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();
size_t size = (env->me_maxreaders-1) * sizeof(MDB_reader) + sizeof(MDB_txninfo);
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, size);
}
close(env->me_lfd);
free(env);
}
/* 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_txn *txn, MDB_dbi dbi, MDB_page *mp, MDB_val *key,
int *exactp, unsigned int *kip)
{
unsigned int i = 0;
int low, high;
int rc = 0;
MDB_node *node;
MDB_val nodekey;
DPRINTF("searching %u keys in %s page %lu",
NUMKEYS(mp),
IS_LEAF(mp) ? "leaf" : "branch",
mp->mp_pgno);
assert(NUMKEYS(mp) > 0);
memset(&nodekey, 0, sizeof(nodekey));
low = IS_LEAF(mp) ? 0 : 1;
high = NUMKEYS(mp) - 1;
while (low <= high) {
i = (low + high) >> 1;
node = NODEPTR(mp, i);
nodekey.mv_size = node->mn_ksize;
nodekey.mv_data = NODEKEY(node);
if (txn->mt_dbxs[dbi].md_cmp)
rc = txn->mt_dbxs[dbi].md_cmp(key, &nodekey);
else
rc = _mdb_cmp(txn, dbi, key, &nodekey);
if (IS_LEAF(mp))
DPRINTF("found leaf index %u [%.*s], rc = %i",
i, (int)nodekey.mv_size, (char *)nodekey.mv_data, rc);
else
DPRINTF("found branch index %u [%.*s -> %lu], rc = %i",
i, (int)node->mn_ksize, (char *)NODEKEY(node),
node->mn_pgno, rc);
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 (i >= NUMKEYS(mp))
/* There is no entry larger or equal to the key. */
return NULL;
}
if (exactp)
*exactp = (rc == 0);
if (kip) /* Store the key index if requested. */
*kip = i;
return NODEPTR(mp, i);
}
static void
cursor_pop_page(MDB_cursor *cursor)
{
MDB_ppage *top;
top = CURSOR_TOP(cursor);
CURSOR_POP(cursor);
DPRINTF("popped page %lu off cursor %p", top->mp_page->mp_pgno, (void *) cursor);
free(top);
}
static MDB_ppage *
cursor_push_page(MDB_cursor *cursor, MDB_page *mp)
{
MDB_ppage *ppage;
DPRINTF("pushing page %lu on cursor %p", mp->mp_pgno, (void *) cursor);
if ((ppage = calloc(1, sizeof(MDB_ppage))) == NULL)
return NULL;
ppage->mp_page = mp;
CURSOR_PUSH(cursor, ppage);
return ppage;
}
static MDB_page *
mdb_get_page(MDB_txn *txn, pgno_t pgno)
{
MDB_page *p = NULL;
int found = 0;
if (!F_ISSET(txn->mt_flags, MDB_TXN_RDONLY) && txn->mt_u.dirty_list[0].mid) {
MDB_dpage *dp;
MIDL2 id;
unsigned x;
id.mid = pgno;
x = mdb_midl2_search(txn->mt_u.dirty_list, &id);
if (x <= txn->mt_u.dirty_list[0].mid && txn->mt_u.dirty_list[x].mid == pgno) {
dp = txn->mt_u.dirty_list[x].mptr;
p = &dp->p;
found = 1;
}
}
if (!found) {
if (pgno > txn->mt_env->me_meta->mm_last_pg)
return NULL;
p = (MDB_page *)(txn->mt_env->me_map + txn->mt_env->me_psize * pgno);
}
return p;
}
static int
mdb_search_page_root(MDB_txn *txn, MDB_dbi dbi, MDB_val *key,
MDB_cursor *cursor, int modify, MDB_pageparent *mpp)
{
MDB_page *mp = mpp->mp_page;
int rc;
if (cursor && cursor_push_page(cursor, mp) == NULL)
return ENOMEM;
while (IS_BRANCH(mp)) {
unsigned int i = 0;
MDB_node *node;
DPRINTF("branch page %lu has %u keys", mp->mp_pgno, NUMKEYS(mp));
assert(NUMKEYS(mp) > 1);
DPRINTF("found index 0 to page %lu", NODEPGNO(NODEPTR(mp, 0)));
if (key == NULL) /* Initialize cursor to first page. */
i = 0;
else if (key->mv_size > MAXKEYSIZE && key->mv_data == NULL) {
/* cursor to last page */
i = NUMKEYS(mp)-1;
} else {
int exact;
node = mdb_search_node(txn, dbi, mp, key, &exact, &i);
if (node == NULL)
i = NUMKEYS(mp) - 1;
else if (!exact) {
assert(i > 0);
i--;
}
}
if (key)
DPRINTF("following index %u for key %.*s",
i, (int)key->mv_size, (char *)key->mv_data);
assert(i < NUMKEYS(mp));
node = NODEPTR(mp, i);
if (cursor)
CURSOR_TOP(cursor)->mp_ki = i;
mpp->mp_parent = mp;
if ((mp = mdb_get_page(txn, NODEPGNO(node))) == NULL)
return MDB_PAGE_NOTFOUND;
mpp->mp_pi = i;
mpp->mp_page = mp;
if (cursor && cursor_push_page(cursor, mp) == NULL)
return ENOMEM;
if (modify) {
MDB_dhead *dh = ((MDB_dhead *)mp)-1;
if ((rc = mdb_touch(txn, mpp)) != 0)
return rc;
dh = ((MDB_dhead *)mpp->mp_page)-1;
dh->md_parent = mpp->mp_parent;
dh->md_pi = mpp->mp_pi;
}
mp = mpp->mp_page;
}
if (!IS_LEAF(mp)) {
DPRINTF("internal error, index points to a %02X page!?",
mp->mp_flags);
return MDB_CORRUPTED;
}
DPRINTF("found leaf page %lu for key %.*s", mp->mp_pgno,
key ? (int)key->mv_size : 0, key ? (char *)key->mv_data : NULL);
return MDB_SUCCESS;
}
/* Search for the page a given key should be in.
* Stores a pointer to the found page in *mpp.
* If key is NULL, search for the lowest page (used by mdb_cursor_first).
* If cursor is non-null, pushes parent pages on the cursor stack.
* If modify is true, visited pages are updated with new page numbers.
*/
static int
mdb_search_page(MDB_txn *txn, MDB_dbi dbi, MDB_val *key,
MDB_cursor *cursor, int modify, MDB_pageparent *mpp)
{
int rc;
pgno_t root;
/* Choose which root page to start with. If a transaction is given
* use the root page from the transaction, otherwise read the last
* committed root page.
*/
if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
DPRINTF("transaction has failed, must abort");
return EINVAL;
} else
root = txn->mt_dbs[dbi].md_root;
if (root == P_INVALID) { /* Tree is empty. */
DPRINTF("tree is empty");
return MDB_NOTFOUND;
}
if ((mpp->mp_page = mdb_get_page(txn, root)) == NULL)
return MDB_PAGE_NOTFOUND;
DPRINTF("root page has flags 0x%X", mpp->mp_page->mp_flags);
if (modify) {
/* For sub-databases, update main root first */
if (dbi > MAIN_DBI && !txn->mt_dbxs[dbi].md_dirty) {
MDB_pageparent mp2;
rc = mdb_search_page(txn, MAIN_DBI, &txn->mt_dbxs[dbi].md_name,
NULL, 1, &mp2);
if (rc)
return rc;
txn->mt_dbxs[dbi].md_dirty = 1;
}
if (!F_ISSET(mpp->mp_page->mp_flags, P_DIRTY)) {
mpp->mp_parent = NULL;
mpp->mp_pi = 0;
if ((rc = mdb_touch(txn, mpp)))
return rc;
txn->mt_dbs[dbi].md_root = mpp->mp_page->mp_pgno;
}
}
return mdb_search_page_root(txn, dbi, key, cursor, modify, mpp);
}
static int
mdb_read_data(MDB_txn *txn, MDB_node *leaf, MDB_val *data)
{
MDB_page *omp; /* overflow mpage */
pgno_t pgno;
if (!F_ISSET(leaf->mn_flags, F_BIGDATA)) {
data->mv_size = leaf->mn_dsize;
data->mv_data = NODEDATA(leaf);
return MDB_SUCCESS;
}
/* Read overflow data.
*/
data->mv_size = leaf->mn_dsize;
memcpy(&pgno, NODEDATA(leaf), sizeof(pgno));
if ((omp = mdb_get_page(txn, pgno)) == NULL) {
DPRINTF("read overflow page %lu failed", pgno);
return MDB_PAGE_NOTFOUND;
}
data->mv_data = omp;
return MDB_SUCCESS;
}
int
mdb_get(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data)
{
int rc, exact;
MDB_node *leaf;
MDB_pageparent mpp;
assert(key);
assert(data);
DPRINTF("===> get key [%.*s]", (int)key->mv_size, (char *)key->mv_data);
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
if ((rc = mdb_search_page(txn, dbi, key, NULL, 0, &mpp)) != MDB_SUCCESS)
return rc;
leaf = mdb_search_node(txn, dbi, mpp.mp_page, key, &exact, NULL);
if (leaf && exact) {
/* Return first duplicate data item */
if (F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
MDB_xcursor mx;
mdb_xcursor_init0(txn, dbi, &mx);
mdb_xcursor_init1(txn, dbi, &mx, leaf);
rc = mdb_search_page(&mx.mx_txn, mx.mx_cursor.mc_dbi, NULL, NULL, 0, &mpp);
if (rc != MDB_SUCCESS)
return rc;
leaf = NODEPTR(mpp.mp_page, 0);
}
rc = mdb_read_data(txn, leaf, data);
} else {
rc = MDB_NOTFOUND;
}
return rc;
}
static int
mdb_sibling(MDB_cursor *cursor, int move_right)
{
int rc;
MDB_node *indx;
MDB_ppage *parent, *top;
MDB_page *mp;
top = CURSOR_TOP(cursor);
if ((parent = SLIST_NEXT(top, mp_entry)) == NULL) {
return MDB_NOTFOUND; /* root has no siblings */
}
DPRINTF("parent page is page %lu, index %u",
parent->mp_page->mp_pgno, parent->mp_ki);
cursor_pop_page(cursor);
if (move_right ? (parent->mp_ki + 1 >= NUMKEYS(parent->mp_page))
: (parent->mp_ki == 0)) {
DPRINTF("no more keys left, moving to %s sibling",
move_right ? "right" : "left");
if ((rc = mdb_sibling(cursor, move_right)) != MDB_SUCCESS)
return rc;
parent = CURSOR_TOP(cursor);
} else {
if (move_right)
parent->mp_ki++;
else
parent->mp_ki--;
DPRINTF("just moving to %s index key %u",
move_right ? "right" : "left", parent->mp_ki);
}
assert(IS_BRANCH(parent->mp_page));
indx = NODEPTR(parent->mp_page, parent->mp_ki);
if ((mp = mdb_get_page(cursor->mc_txn, indx->mn_pgno)) == NULL)
return MDB_PAGE_NOTFOUND;
#if 0
mp->parent = parent->mp_page;
mp->parent_index = parent->mp_ki;
#endif
cursor_push_page(cursor, mp);
return MDB_SUCCESS;
}
static int
mdb_set_key(MDB_node *node, MDB_val *key)
{
if (key == NULL)
return 0;
key->mv_size = node->mn_ksize;
key->mv_data = NODEKEY(node);
return 0;
}
static int
mdb_cursor_next(MDB_cursor *cursor, MDB_val *key, MDB_val *data, MDB_cursor_op op)
{
MDB_ppage *top;
MDB_page *mp;
MDB_node *leaf;
int rc;
if (cursor->mc_eof) {
return MDB_NOTFOUND;
}
assert(cursor->mc_initialized);
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
rc = mdb_cursor_next(&cursor->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
if (op != MDB_NEXT || rc == MDB_SUCCESS)
return rc;
}
}
top = CURSOR_TOP(cursor);
mp = top->mp_page;
DPRINTF("cursor_next: top page is %lu in cursor %p", mp->mp_pgno, (void *) cursor);
if (top->mp_ki + 1 >= NUMKEYS(mp)) {
DPRINTF("=====> move to next sibling page");
if (mdb_sibling(cursor, 1) != MDB_SUCCESS) {
cursor->mc_eof = 1;
return MDB_NOTFOUND;
}
top = CURSOR_TOP(cursor);
mp = top->mp_page;
DPRINTF("next page is %lu, key index %u", mp->mp_pgno, top->mp_ki);
} else
top->mp_ki++;
DPRINTF("==> cursor points to page %lu with %u keys, key index %u",
mp->mp_pgno, NUMKEYS(mp), top->mp_ki);
assert(IS_LEAF(mp));
leaf = NODEPTR(mp, top->mp_ki);
if (data) {
if ((rc = mdb_read_data(cursor->mc_txn, leaf, data) != MDB_SUCCESS))
return rc;
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
mdb_xcursor_init1(cursor->mc_txn, cursor->mc_dbi, cursor->mc_xcursor, leaf);
rc = mdb_cursor_first(&cursor->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
return mdb_set_key(leaf, key);
}
static int
mdb_cursor_prev(MDB_cursor *cursor, MDB_val *key, MDB_val *data, MDB_cursor_op op)
{
MDB_ppage *top;
MDB_page *mp;
MDB_node *leaf;
int rc;
assert(cursor->mc_initialized);
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
if (op == MDB_PREV || op == MDB_PREV_DUP) {
rc = mdb_cursor_prev(&cursor->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
if (op != MDB_PREV || rc == MDB_SUCCESS)
return rc;
}
}
top = CURSOR_TOP(cursor);
mp = top->mp_page;
DPRINTF("cursor_prev: top page is %lu in cursor %p", mp->mp_pgno, (void *) cursor);
if (top->mp_ki == 0) {
DPRINTF("=====> move to prev sibling page");
if (mdb_sibling(cursor, 0) != MDB_SUCCESS) {
return MDB_NOTFOUND;
}
top = CURSOR_TOP(cursor);
mp = top->mp_page;
top->mp_ki = NUMKEYS(mp) - 1;
DPRINTF("prev page is %lu, key index %u", mp->mp_pgno, top->mp_ki);
} else
top->mp_ki--;
cursor->mc_eof = 0;
DPRINTF("==> cursor points to page %lu with %u keys, key index %u",
mp->mp_pgno, NUMKEYS(mp), top->mp_ki);
assert(IS_LEAF(mp));
leaf = NODEPTR(mp, top->mp_ki);
if (data) {
if ((rc = mdb_read_data(cursor->mc_txn, leaf, data) != MDB_SUCCESS))
return rc;
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
mdb_xcursor_init1(cursor->mc_txn, cursor->mc_dbi, cursor->mc_xcursor, leaf);
rc = mdb_cursor_last(&cursor->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
return mdb_set_key(leaf, key);
}
static int
mdb_cursor_set(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
MDB_cursor_op op, int *exactp)
{
int rc;
MDB_node *leaf;
MDB_ppage *top;
MDB_pageparent mpp;
assert(cursor);
assert(key);
assert(key->mv_size > 0);
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
rc = mdb_search_page(cursor->mc_txn, cursor->mc_dbi, key, cursor, 0, &mpp);
if (rc != MDB_SUCCESS)
return rc;
assert(IS_LEAF(mpp.mp_page));
top = CURSOR_TOP(cursor);
leaf = mdb_search_node(cursor->mc_txn, cursor->mc_dbi, mpp.mp_page, key, exactp, &top->mp_ki);
if (exactp != NULL && !*exactp) {
/* MDB_SET specified and not an exact match. */
return MDB_NOTFOUND;
}
if (leaf == NULL) {
DPRINTF("===> inexact leaf not found, goto sibling");
if ((rc = mdb_sibling(cursor, 1)) != MDB_SUCCESS)
return rc; /* no entries matched */
top = CURSOR_TOP(cursor);
top->mp_ki = 0;
mpp.mp_page = top->mp_page;
assert(IS_LEAF(mpp.mp_page));
leaf = NODEPTR(mpp.mp_page, 0);
}
cursor->mc_initialized = 1;
cursor->mc_eof = 0;
if (data) {
MDB_val d2;
if ((rc = mdb_read_data(cursor->mc_txn, leaf, &d2)) != MDB_SUCCESS)
return rc;
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
mdb_xcursor_init1(cursor->mc_txn, cursor->mc_dbi, cursor->mc_xcursor, leaf);
if (op == MDB_SET || op == MDB_SET_RANGE) {
rc = mdb_cursor_first(&cursor->mc_xcursor->mx_cursor, data, NULL);
} else {
int ex2, *ex2p;
MDB_cursor_op op2;
if (op == MDB_GET_BOTH) {
ex2p = &ex2;
op2 = MDB_SET;
} else {
ex2p = NULL;
op2 = MDB_SET_RANGE;
}
rc = mdb_cursor_set(&cursor->mc_xcursor->mx_cursor, data, NULL, op2, ex2p);
if (rc != MDB_SUCCESS)
return rc;
}
} else {
*data = d2;
}
}
rc = mdb_set_key(leaf, key);
if (rc == MDB_SUCCESS) {
DPRINTF("==> cursor placed on key %.*s",
(int)key->mv_size, (char *)key->mv_data);
;
}
return rc;
}
static int
mdb_cursor_first(MDB_cursor *cursor, MDB_val *key, MDB_val *data)
{
int rc;
MDB_pageparent mpp;
MDB_node *leaf;
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
rc = mdb_search_page(cursor->mc_txn, cursor->mc_dbi, NULL, cursor, 0, &mpp);
if (rc != MDB_SUCCESS)
return rc;
assert(IS_LEAF(mpp.mp_page));
leaf = NODEPTR(mpp.mp_page, 0);
cursor->mc_initialized = 1;
cursor->mc_eof = 0;
if (data) {
if ((rc = mdb_read_data(cursor->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
mdb_xcursor_init1(cursor->mc_txn, cursor->mc_dbi, cursor->mc_xcursor, leaf);
rc = mdb_cursor_first(&cursor->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
}
}
return mdb_set_key(leaf, key);
}
static int
mdb_cursor_last(MDB_cursor *cursor, MDB_val *key, MDB_val *data)
{
int rc;
MDB_ppage *top;
MDB_pageparent mpp;
MDB_node *leaf;
MDB_val lkey;
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
lkey.mv_size = MAXKEYSIZE+1;
lkey.mv_data = NULL;
rc = mdb_search_page(cursor->mc_txn, cursor->mc_dbi, &lkey, cursor, 0, &mpp);
if (rc != MDB_SUCCESS)
return rc;
assert(IS_LEAF(mpp.mp_page));
leaf = NODEPTR(mpp.mp_page, NUMKEYS(mpp.mp_page)-1);
cursor->mc_initialized = 1;
cursor->mc_eof = 0;
top = CURSOR_TOP(cursor);
top->mp_ki = NUMKEYS(top->mp_page) - 1;
if (data) {
if ((rc = mdb_read_data(cursor->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
mdb_xcursor_init1(cursor->mc_txn, cursor->mc_dbi, cursor->mc_xcursor, leaf);
rc = mdb_cursor_last(&cursor->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
}
}
return mdb_set_key(leaf, key);
}
int
mdb_cursor_get(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
MDB_cursor_op op)
{
int rc;
int exact = 0;
assert(cursor);
switch (op) {
case MDB_GET_BOTH:
case MDB_GET_BOTH_RANGE:
if (data == 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(cursor, key, data, op, NULL);
else
rc = mdb_cursor_set(cursor, key, data, op, &exact);
break;
case MDB_NEXT:
case MDB_NEXT_DUP:
case MDB_NEXT_NODUP:
if (!cursor->mc_initialized)
rc = mdb_cursor_first(cursor, key, data);
else
rc = mdb_cursor_next(cursor, key, data, op);
break;
case MDB_PREV:
case MDB_PREV_DUP:
case MDB_PREV_NODUP:
if (!cursor->mc_initialized || cursor->mc_eof)
rc = mdb_cursor_last(cursor, key, data);
else
rc = mdb_cursor_prev(cursor, key, data, op);
break;
case MDB_FIRST:
rc = mdb_cursor_first(cursor, key, data);
break;
case MDB_LAST:
rc = mdb_cursor_last(cursor, key, data);
break;
default:
DPRINTF("unhandled/unimplemented cursor operation %u", op);
rc = EINVAL;
break;
}
return rc;
}
/* Allocate a page and initialize it
*/
static MDB_dpage *
mdb_new_page(MDB_txn *txn, MDB_dbi dbi, uint32_t flags, int num)
{
MDB_dpage *dp;
if ((dp = mdb_alloc_page(txn, NULL, 0, num)) == NULL)
return NULL;
DPRINTF("allocated new mpage %lu, page size %u",
dp->p.mp_pgno, txn->mt_env->me_psize);
dp->p.mp_flags = flags | P_DIRTY;
dp->p.mp_lower = PAGEHDRSZ;
dp->p.mp_upper = txn->mt_env->me_psize;
if (IS_BRANCH(&dp->p))
txn->mt_dbs[dbi].md_branch_pages++;
else if (IS_LEAF(&dp->p))
txn->mt_dbs[dbi].md_leaf_pages++;
else if (IS_OVERFLOW(&dp->p)) {
txn->mt_dbs[dbi].md_overflow_pages += num;
dp->p.mp_pages = num;
}
return dp;
}
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);
}
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_txn *txn, MDB_dbi dbi, MDB_page *mp, 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_dpage *ofp = NULL; /* overflow page */
assert(mp->mp_upper >= mp->mp_lower);
DPRINTF("add node [%.*s] to %s page %lu at index %i, key size %zu",
key ? (int)key->mv_size : 0, key ? (char *)key->mv_data : NULL,
IS_LEAF(mp) ? "leaf" : "branch",
mp->mp_pgno, indx, key ? key->mv_size : 0);
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 >= txn->mt_env->me_psize / MDB_MINKEYS) {
int ovpages = OVPAGES(data->mv_size, 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(txn, dbi, P_OVERFLOW, ovpages)) == NULL)
return ENOMEM;
DPRINTF("allocated overflow page %lu", ofp->p.mp_pgno);
flags |= F_BIGDATA;
} else {
node_size += data->mv_size;
}
}
if (node_size + sizeof(indx_t) > SIZELEFT(mp)) {
DPRINTF("not enough room in page %lu, 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))
node->mn_dsize = data->mv_size;
else
node->mn_pgno = 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->p.mp_pgno,
sizeof(pgno_t));
memcpy(METADATA(&ofp->p), data->mv_data, data->mv_size);
}
}
return MDB_SUCCESS;
}
static void
mdb_del_node(MDB_page *mp, indx_t indx)
{
unsigned int sz;
indx_t i, j, numkeys, ptr;
MDB_node *node;
char *base;
DPRINTF("delete node %u on %s page %lu", indx,
IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno);
assert(indx < NUMKEYS(mp));
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);
}
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_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
{
MDB_dbi dbn;
mx->mx_txn = *txn;
mx->mx_txn.mt_dbxs = mx->mx_dbxs;
mx->mx_txn.mt_dbs = mx->mx_dbs;
mx->mx_dbxs[0] = txn->mt_dbxs[0];
mx->mx_dbxs[1] = txn->mt_dbxs[1];
if (dbi > 1) {
mx->mx_dbxs[2] = txn->mt_dbxs[dbi];
dbn = 2;
} else {
dbn = 1;
}
mx->mx_dbxs[dbn+1].md_parent = dbn;
mx->mx_dbxs[dbn+1].md_cmp = mx->mx_dbxs[dbn].md_dcmp;
mx->mx_dbxs[dbn+1].md_rel = mx->mx_dbxs[dbn].md_rel;
mx->mx_dbxs[dbn+1].md_dirty = 0;
mx->mx_txn.mt_numdbs = dbn+2;
SLIST_INIT(&mx->mx_cursor.mc_stack);
mx->mx_cursor.mc_txn = &mx->mx_txn;
mx->mx_cursor.mc_dbi = dbn+1;
}
static void
mdb_xcursor_init1(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx, MDB_node *node)
{
MDB_db *db = NODEDATA(node);
MDB_dbi dbn;
mx->mx_dbs[0] = txn->mt_dbs[0];
mx->mx_dbs[1] = txn->mt_dbs[1];
if (dbi > 1) {
mx->mx_dbs[2] = txn->mt_dbs[dbi];
dbn = 3;
} else {
dbn = 2;
}
mx->mx_dbs[dbn] = *db;
mx->mx_dbxs[dbn].md_name.mv_data = NODEKEY(node);
mx->mx_dbxs[dbn].md_name.mv_size = node->mn_ksize;
mx->mx_txn.mt_next_pgno = txn->mt_next_pgno;
mx->mx_txn.mt_oldest = txn->mt_oldest;
mx->mx_txn.mt_u = txn->mt_u;
}
static void
mdb_xcursor_fini(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
{
txn->mt_next_pgno = mx->mx_txn.mt_next_pgno;
txn->mt_oldest = mx->mx_txn.mt_oldest;
txn->mt_u = mx->mx_txn.mt_u;
txn->mt_dbs[0] = mx->mx_dbs[0];
txn->mt_dbs[1] = mx->mx_dbs[1];
txn->mt_dbxs[0].md_dirty = mx->mx_dbxs[0].md_dirty;
txn->mt_dbxs[1].md_dirty = mx->mx_dbxs[1].md_dirty;
if (dbi > 1) {
txn->mt_dbs[dbi] = mx->mx_dbs[2];
txn->mt_dbxs[dbi].md_dirty = mx->mx_dbxs[2].md_dirty;
}
}
int
mdb_cursor_open(MDB_txn *txn, MDB_dbi dbi, MDB_cursor **ret)
{
MDB_cursor *cursor;
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 ((cursor = calloc(1, size)) != NULL) {
SLIST_INIT(&cursor->mc_stack);
cursor->mc_dbi = dbi;
cursor->mc_txn = txn;
if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) {
MDB_xcursor *mx = (MDB_xcursor *)(cursor + 1);
cursor->mc_xcursor = mx;
mdb_xcursor_init0(txn, dbi, mx);
}
} else {
return ENOMEM;
}
*ret = cursor;
return MDB_SUCCESS;
}
/* Return the count of duplicate data items for the current key */
int
mdb_cursor_count(MDB_cursor *mc, unsigned long *countp)
{
if (mc == NULL || countp == NULL)
return EINVAL;
if (!(mc->mc_txn->mt_dbs[mc->mc_dbi].md_flags & MDB_DUPSORT))
return EINVAL;
if (!mc->mc_xcursor->mx_cursor.mc_initialized)
return EINVAL;
*countp = mc->mc_xcursor->mx_txn.mt_dbs[mc->mc_xcursor->mx_cursor.mc_dbi].md_entries;
return MDB_SUCCESS;
}
void
mdb_cursor_close(MDB_cursor *cursor)
{
if (cursor != NULL) {
while(!CURSOR_EMPTY(cursor))
cursor_pop_page(cursor);
if (cursor->mc_txn->mt_dbs[cursor->mc_dbi].md_flags & MDB_DUPSORT) {
while(!CURSOR_EMPTY(&cursor->mc_xcursor->mx_cursor))
cursor_pop_page(&cursor->mc_xcursor->mx_cursor);
}
free(cursor);
}
}
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;
node = NODEPTR(mp, indx);
ptr = mp->mp_ptrs[indx];
DPRINTF("update key %u (ofs %u) [%.*s] to [%.*s] on page %lu",
indx, ptr,
(int)node->mn_ksize, (char *)NODEKEY(node),
(int)key->mv_size, (char *)key->mv_data,
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 src to dst.
*/
static int
mdb_move_node(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *src, indx_t srcindx,
MDB_pageparent *dst, indx_t dstindx)
{
int rc;
MDB_node *srcnode;
MDB_val key, data;
srcnode = NODEPTR(src->mp_page, srcindx);
DPRINTF("moving %s node %u [%.*s] on page %lu to node %u on page %lu",
IS_LEAF(src->mp_page) ? "leaf" : "branch",
srcindx,
(int)srcnode->mn_ksize, (char *)NODEKEY(srcnode),
src->mp_page->mp_pgno,
dstindx, dst->mp_page->mp_pgno);
/* Mark src and dst as dirty. */
if ((rc = mdb_touch(txn, src)) ||
(rc = mdb_touch(txn, dst)))
return rc;;
/* Add the node to the destination page.
*/
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(txn, dbi, dst->mp_page, dstindx, &key, &data, NODEPGNO(srcnode),
srcnode->mn_flags);
if (rc != MDB_SUCCESS)
return rc;
/* Delete the node from the source page.
*/
mdb_del_node(src->mp_page, srcindx);
/* Update the parent separators.
*/
if (srcindx == 0 && src->mp_pi != 0) {
DPRINTF("update separator for source page %lu to [%.*s]",
src->mp_page->mp_pgno, (int)key.mv_size, (char *)key.mv_data);
if ((rc = mdb_update_key(src->mp_parent, src->mp_pi,
&key)) != MDB_SUCCESS)
return rc;
}
if (srcindx == 0 && IS_BRANCH(src->mp_page)) {
MDB_val nullkey;
nullkey.mv_size = 0;
assert(mdb_update_key(src->mp_page, 0, &nullkey) == MDB_SUCCESS);
}
if (dstindx == 0 && dst->mp_pi != 0) {
DPRINTF("update separator for destination page %lu to [%.*s]",
dst->mp_page->mp_pgno, (int)key.mv_size, (char *)key.mv_data);
if ((rc = mdb_update_key(dst->mp_parent, dst->mp_pi,
&key)) != MDB_SUCCESS)
return rc;
}
if (dstindx == 0 && IS_BRANCH(dst->mp_page)) {
MDB_val nullkey;
nullkey.mv_size = 0;
assert(mdb_update_key(dst->mp_page, 0, &nullkey) == MDB_SUCCESS);
}
return MDB_SUCCESS;
}
static int
mdb_merge(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *src, MDB_pageparent *dst)
{
int rc;
indx_t i;
MDB_node *srcnode;
MDB_val key, data;
MDB_pageparent mpp;
MDB_dhead *dh;
DPRINTF("merging page %lu and %lu", src->mp_page->mp_pgno, dst->mp_page->mp_pgno);
assert(txn != NULL);
assert(src->mp_parent); /* can't merge root page */
assert(dst->mp_parent);
/* Mark src and dst as dirty. */
if ((rc = mdb_touch(txn, src)) ||
(rc = mdb_touch(txn, dst)))
return rc;
/* Move all nodes from src to dst.
*/
for (i = 0; i < NUMKEYS(src->mp_page); i++) {
srcnode = NODEPTR(src->mp_page, 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(txn, dbi, dst->mp_page, NUMKEYS(dst->mp_page), &key,
&data, NODEPGNO(srcnode), srcnode->mn_flags);
if (rc != MDB_SUCCESS)
return rc;
}
DPRINTF("dst page %lu now has %u keys (%.1f%% filled)",
dst->mp_page->mp_pgno, NUMKEYS(dst->mp_page), (float)PAGEFILL(txn->mt_env, dst->mp_page) / 10);
/* Unlink the src page from parent.
*/
mdb_del_node(src->mp_parent, src->mp_pi);
if (src->mp_pi == 0) {
key.mv_size = 0;
if ((rc = mdb_update_key(src->mp_parent, 0, &key)) != MDB_SUCCESS)
return rc;
}
if (IS_LEAF(src->mp_page))
txn->mt_dbs[dbi].md_leaf_pages--;
else
txn->mt_dbs[dbi].md_branch_pages--;
mpp.mp_page = src->mp_parent;
dh = (MDB_dhead *)src->mp_parent;
dh--;
mpp.mp_parent = dh->md_parent;
mpp.mp_pi = dh->md_pi;
return mdb_rebalance(txn, dbi, &mpp);
}
#define FILL_THRESHOLD 250
static int
mdb_rebalance(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *mpp)
{
MDB_node *node;
MDB_page *root;
MDB_pageparent npp;
indx_t si = 0, di = 0;
assert(txn != NULL);
assert(mpp != NULL);
DPRINTF("rebalancing %s page %lu (has %u keys, %.1f%% full)",
IS_LEAF(mpp->mp_page) ? "leaf" : "branch",
mpp->mp_page->mp_pgno, NUMKEYS(mpp->mp_page), (float)PAGEFILL(txn->mt_env, mpp->mp_page) / 10);
if (PAGEFILL(txn->mt_env, mpp->mp_page) >= FILL_THRESHOLD) {
DPRINTF("no need to rebalance page %lu, above fill threshold",
mpp->mp_page->mp_pgno);
return MDB_SUCCESS;
}
if (mpp->mp_parent == NULL) {
if (NUMKEYS(mpp->mp_page) == 0) {
DPRINTF("tree is completely empty");
txn->mt_dbs[dbi].md_root = P_INVALID;
txn->mt_dbs[dbi].md_depth--;
txn->mt_dbs[dbi].md_leaf_pages--;
} else if (IS_BRANCH(mpp->mp_page) && NUMKEYS(mpp->mp_page) == 1) {
DPRINTF("collapsing root page!");
txn->mt_dbs[dbi].md_root = NODEPGNO(NODEPTR(mpp->mp_page, 0));
if ((root = mdb_get_page(txn, txn->mt_dbs[dbi].md_root)) == NULL)
return MDB_PAGE_NOTFOUND;
txn->mt_dbs[dbi].md_depth--;
txn->mt_dbs[dbi].md_branch_pages--;
} else
DPRINTF("root page doesn't need rebalancing");
return MDB_SUCCESS;
}
/* The parent (branch page) must have at least 2 pointers,
* otherwise the tree is invalid.
*/
assert(NUMKEYS(mpp->mp_parent) > 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.
*/
if (mpp->mp_pi == 0) {
/* We're the leftmost leaf in our parent.
*/
DPRINTF("reading right neighbor");
node = NODEPTR(mpp->mp_parent, mpp->mp_pi + 1);
if ((npp.mp_page = mdb_get_page(txn, NODEPGNO(node))) == NULL)
return MDB_PAGE_NOTFOUND;
npp.mp_pi = mpp->mp_pi + 1;
si = 0;
di = NUMKEYS(mpp->mp_page);
} else {
/* There is at least one neighbor to the left.
*/
DPRINTF("reading left neighbor");
node = NODEPTR(mpp->mp_parent, mpp->mp_pi - 1);
if ((npp.mp_page = mdb_get_page(txn, NODEPGNO(node))) == NULL)
return MDB_PAGE_NOTFOUND;
npp.mp_pi = mpp->mp_pi - 1;
si = NUMKEYS(npp.mp_page) - 1;
di = 0;
}
npp.mp_parent = mpp->mp_parent;
DPRINTF("found neighbor page %lu (%u keys, %.1f%% full)",
npp.mp_page->mp_pgno, NUMKEYS(npp.mp_page), (float)PAGEFILL(txn->mt_env, npp.mp_page) / 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(txn->mt_env, npp.mp_page) >= FILL_THRESHOLD && NUMKEYS(npp.mp_page) >= 2)
return mdb_move_node(txn, dbi, &npp, si, mpp, di);
else { /* FIXME: if (has_enough_room()) */
if (mpp->mp_pi == 0)
return mdb_merge(txn, dbi, &npp, mpp);
else
return mdb_merge(txn, dbi, mpp, &npp);
}
}
static int
mdb_del0(MDB_txn *txn, MDB_dbi dbi, unsigned int ki, MDB_pageparent *mpp, MDB_node *leaf)
{
int rc;
/* add overflow pages to free list */
if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
int i, ovpages;
pgno_t pg;
memcpy(&pg, NODEDATA(leaf), sizeof(pg));
ovpages = OVPAGES(NODEDSZ(leaf), txn->mt_env->me_psize);
for (i=0; i<ovpages; i++) {
DPRINTF("freed ov page %lu", pg);
mdb_midl_insert(txn->mt_free_pgs, pg);
pg++;
}
}
mdb_del_node(mpp->mp_page, ki);
txn->mt_dbs[dbi].md_entries--;
rc = mdb_rebalance(txn, dbi, mpp);
if (rc != MDB_SUCCESS)
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
int
mdb_del(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data,
unsigned int flags)
{
int rc, exact;
unsigned int ki;
MDB_node *leaf;
MDB_pageparent mpp;
DPRINTF("========> delete key %.*s", (int)key->mv_size, (char *)key->mv_data);
assert(key != NULL);
if (txn == NULL || !dbi || dbi >= txn->mt_numdbs)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
return EINVAL;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
if ((rc = mdb_search_page(txn, dbi, key, NULL, 1, &mpp)) != MDB_SUCCESS)
return rc;
leaf = mdb_search_node(txn, dbi, mpp.mp_page, key, &exact, &ki);
if (leaf == NULL || !exact) {
return MDB_NOTFOUND;
}
if (F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
MDB_xcursor mx;
MDB_pageparent mp2;
mdb_xcursor_init0(txn, dbi, &mx);
mdb_xcursor_init1(txn, dbi, &mx, leaf);
if (flags == MDB_DEL_DUP) {
rc = mdb_del(&mx.mx_txn, mx.mx_cursor.mc_dbi, data, NULL, 0);
mdb_xcursor_fini(txn, dbi, &mx);
if (rc != MDB_SUCCESS)
return rc;
/* If sub-DB still has entries, we're done */
if (mx.mx_txn.mt_dbs[mx.mx_cursor.mc_dbi].md_root != P_INVALID) {
memcpy(NODEDATA(leaf), &mx.mx_txn.mt_dbs[mx.mx_cursor.mc_dbi],
sizeof(MDB_db));
return rc;
}
/* otherwise fall thru and delete the sub-DB */
} else {
/* add all the child DB's pages to the free list */
rc = mdb_search_page(&mx.mx_txn, mx.mx_cursor.mc_dbi,
NULL, &mx.mx_cursor, 0, &mp2);
if (rc == MDB_SUCCESS) {
MDB_ppage *top, *parent;
MDB_node *ni;
unsigned int i;
cursor_pop_page(&mx.mx_cursor);
top = CURSOR_TOP(&mx.mx_cursor);
if (top != NULL) {
parent = SLIST_NEXT(top, mp_entry);
while (parent != NULL) {
for (i=0; i<NUMKEYS(top->mp_page); i++) {
ni = NODEPTR(top->mp_page, i);
mdb_midl_insert(txn->mt_free_pgs, ni->mn_pgno);
}
if (parent) {
parent->mp_ki++;
if (parent->mp_ki >= NUMKEYS(parent->mp_page)) {
cursor_pop_page(&mx.mx_cursor);
top = CURSOR_TOP(&mx.mx_cursor);
parent = SLIST_NEXT(top, mp_entry);
} else {
ni = NODEPTR(parent->mp_page, parent->mp_ki);
top->mp_page = mdb_get_page(&mx.mx_txn, ni->mn_pgno);
}
}
}
}
mdb_midl_insert(txn->mt_free_pgs, mx.mx_txn.mt_dbs[mx.mx_cursor.mc_dbi].md_root);
}
}
}
if (data && (rc = mdb_read_data(txn, leaf, data)) != MDB_SUCCESS)
return rc;
return mdb_del0(txn, dbi, ki, &mpp, leaf);
}
/* Split page <*mpp>, and insert <key,(data|newpgno)> in either left or
* right sibling, at index <*newindxp> (as if unsplit). Updates *mpp and
* *newindxp with the actual values after split, ie if *mpp and *newindxp
* refer to a node in the new right sibling page.
*/
static int
mdb_split(MDB_txn *txn, MDB_dbi dbi, MDB_page **mpp, unsigned int *newindxp,
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;
MDB_node *node;
MDB_val sepkey, rkey, rdata;
MDB_page *copy;
MDB_dpage *mdp, *rdp, *pdp;
MDB_dhead *dh;
assert(txn != NULL);
dh = ((MDB_dhead *)*mpp) - 1;
mdp = (MDB_dpage *)dh;
newindx = *newindxp;
DPRINTF("-----> splitting %s page %lu and adding [%.*s] at index %i",
IS_LEAF(&mdp->p) ? "leaf" : "branch", mdp->p.mp_pgno,
(int)newkey->mv_size, (char *)newkey->mv_data, *newindxp);
if (mdp->h.md_parent == NULL) {
if ((pdp = mdb_new_page(txn, dbi, P_BRANCH, 1)) == NULL)
return ENOMEM;
mdp->h.md_pi = 0;
mdp->h.md_parent = &pdp->p;
txn->mt_dbs[dbi].md_root = pdp->p.mp_pgno;
DPRINTF("root split! new root = %lu", pdp->p.mp_pgno);
txn->mt_dbs[dbi].md_depth++;
/* Add left (implicit) pointer. */
if ((rc = mdb_add_node(txn, dbi, &pdp->p, 0, NULL, NULL,
mdp->p.mp_pgno, 0)) != MDB_SUCCESS)
return rc;
} else {
DPRINTF("parent branch page is %lu", mdp->h.md_parent->mp_pgno);
}
/* Create a right sibling. */
if ((rdp = mdb_new_page(txn, dbi, mdp->p.mp_flags, 1)) == NULL)
return ENOMEM;
rdp->h.md_parent = mdp->h.md_parent;
rdp->h.md_pi = mdp->h.md_pi + 1;
DPRINTF("new right sibling: page %lu", rdp->p.mp_pgno);
/* Move half of the keys to the right sibling. */
if ((copy = malloc(txn->mt_env->me_psize)) == NULL)
return ENOMEM;
memcpy(copy, &mdp->p, txn->mt_env->me_psize);
memset(&mdp->p.mp_ptrs, 0, txn->mt_env->me_psize - PAGEHDRSZ);
mdp->p.mp_lower = PAGEHDRSZ;
mdp->p.mp_upper = txn->mt_env->me_psize;
split_indx = NUMKEYS(copy) / 2 + 1;
/* First find the separating key between the split pages.
*/
memset(&sepkey, 0, sizeof(sepkey));
if (newindx == split_indx) {
sepkey.mv_size = newkey->mv_size;
sepkey.mv_data = newkey->mv_data;
} else {
node = NODEPTR(copy, split_indx);
sepkey.mv_size = node->mn_ksize;
sepkey.mv_data = NODEKEY(node);
}
DPRINTF("separator is [%.*s]", (int)sepkey.mv_size, (char *)sepkey.mv_data);
/* Copy separator key to the parent.
*/
if (SIZELEFT(rdp->h.md_parent) < mdb_branch_size(txn->mt_env, &sepkey)) {
rc = mdb_split(txn, dbi, &rdp->h.md_parent, &rdp->h.md_pi,
&sepkey, NULL, rdp->p.mp_pgno);
/* Right page might now have changed parent.
* Check if left page also changed parent.
*/
if (rdp->h.md_parent != mdp->h.md_parent &&
mdp->h.md_pi >= NUMKEYS(mdp->h.md_parent)) {
mdp->h.md_parent = rdp->h.md_parent;
mdp->h.md_pi = rdp->h.md_pi - 1;
}
} else {
rc = mdb_add_node(txn, dbi, rdp->h.md_parent, rdp->h.md_pi,
&sepkey, NULL, rdp->p.mp_pgno, 0);
}
if (rc != MDB_SUCCESS) {
free(copy);
return rc;
}
for (i = j = 0; i <= NUMKEYS(copy); j++) {
if (i < split_indx) {
/* Re-insert in left sibling. */
pdp = mdp;
} else {
/* Insert in right sibling. */
if (i == split_indx)
/* Reset insert index for right sibling. */
j = (i == newindx && ins_new);
pdp = rdp;
}
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(&mdp->p)) {
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. */
*newindxp = j;
*mpp = &pdp->p;
} else if (i == NUMKEYS(copy)) {
break;
} else {
node = NODEPTR(copy, i);
rkey.mv_data = NODEKEY(node);
rkey.mv_size = node->mn_ksize;
if (IS_LEAF(&mdp->p)) {
rdata.mv_data = NODEDATA(node);
rdata.mv_size = node->mn_dsize;
} else
pgno = node->mn_pgno;
flags = node->mn_flags;
i++;
}
if (!IS_LEAF(&mdp->p) && j == 0) {
/* First branch index doesn't need key data. */
rkey.mv_size = 0;
}
rc = mdb_add_node(txn, dbi, &pdp->p, j, &rkey, &rdata, pgno,flags);
}
free(copy);
return rc;
}
static int
mdb_put0(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data, unsigned int flags)
{
int rc = MDB_SUCCESS, exact;
unsigned int ki;
MDB_node *leaf;
MDB_pageparent mpp;
MDB_val xdata, *rdata;
MDB_db dummy;
DPRINTF("==> put key %.*s, size %zu, data size %zu",
(int)key->mv_size, (char *)key->mv_data, key->mv_size, data->mv_size);
mpp.mp_parent = NULL;
mpp.mp_pi = 0;
rc = mdb_search_page(txn, dbi, key, NULL, 1, &mpp);
if (rc == MDB_SUCCESS) {
leaf = mdb_search_node(txn, dbi, mpp.mp_page, key, &exact, &ki);
if (leaf && exact) {
if (F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
goto put_sub;
}
if (flags == MDB_NOOVERWRITE) {
DPRINTF("duplicate key %.*s",
(int)key->mv_size, (char *)key->mv_data);
return MDB_KEYEXIST;
}
/* same size, just replace it */
if (NODEDSZ(leaf) == data->mv_size) {
memcpy(NODEDATA(leaf), data->mv_data, data->mv_size);
goto done;
}
mdb_del_node(mpp.mp_page, ki);
}
if (leaf == NULL) { /* append if not found */
ki = NUMKEYS(mpp.mp_page);
DPRINTF("appending key at index %i", ki);
}
} else if (rc == MDB_NOTFOUND) {
MDB_dpage *dp;
/* new file, just write a root leaf page */
DPRINTF("allocating new root leaf page");
if ((dp = mdb_new_page(txn, dbi, P_LEAF, 1)) == NULL) {
return ENOMEM;
}
mpp.mp_page = &dp->p;
txn->mt_dbs[dbi].md_root = mpp.mp_page->mp_pgno;
txn->mt_dbs[dbi].md_depth++;
ki = 0;
}
else
goto done;
assert(IS_LEAF(mpp.mp_page));
DPRINTF("there are %u keys, should insert new key at index %i",
NUMKEYS(mpp.mp_page), ki);
/* For sorted dups, the data item at this level is a DB record
* for a child DB; the actual data elements are stored as keys
* in the child DB.
*/
if (F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
rdata = &xdata;
xdata.mv_size = sizeof(MDB_db);
xdata.mv_data = &dummy;
memset(&dummy, 0, sizeof(dummy));
dummy.md_root = P_INVALID;
} else {
rdata = data;
}
if (SIZELEFT(mpp.mp_page) < mdb_leaf_size(txn->mt_env, key, rdata)) {
rc = mdb_split(txn, dbi, &mpp.mp_page, &ki, key, rdata, P_INVALID);
} else {
/* There is room already in this leaf page. */
rc = mdb_add_node(txn, dbi, mpp.mp_page, ki, key, rdata, 0, 0);
}
if (rc != MDB_SUCCESS)
txn->mt_flags |= MDB_TXN_ERROR;
else {
txn->mt_dbs[dbi].md_entries++;
/* Remember if we just added a subdatabase */
if (flags & F_SUBDATA) {
leaf = NODEPTR(mpp.mp_page, ki);
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 (F_ISSET(txn->mt_dbs[dbi].md_flags, MDB_DUPSORT)) {
MDB_xcursor mx;
leaf = NODEPTR(mpp.mp_page, ki);
put_sub:
mdb_xcursor_init0(txn, dbi, &mx);
mdb_xcursor_init1(txn, dbi, &mx, leaf);
xdata.mv_size = 0;
xdata.mv_data = "";
if (flags == MDB_NODUPDATA)
flags = MDB_NOOVERWRITE;
rc = mdb_put0(&mx.mx_txn, mx.mx_cursor.mc_dbi, data, &xdata, flags);
mdb_xcursor_fini(txn, dbi, &mx);
memcpy(NODEDATA(leaf), &mx.mx_txn.mt_dbs[mx.mx_cursor.mc_dbi],
sizeof(MDB_db));
}
}
done:
return rc;
}
int
mdb_put(MDB_txn *txn, MDB_dbi dbi,
MDB_val *key, MDB_val *data, unsigned int flags)
{
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 EINVAL;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
if ((flags & (MDB_NOOVERWRITE|MDB_NODUPDATA)) != flags)
return EINVAL;
return mdb_put0(txn, dbi, key, data, flags);
}
int
mdb_env_set_flags(MDB_env *env, unsigned int flag, int onoff)
{
#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)
{
if (env == NULL || arg == NULL)
return EINVAL;
return mdb_stat0(env, &env->me_meta->mm_dbs[MAIN_DBI], arg);
}
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;
/* 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));
return MDB_SUCCESS;
}
/* 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_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;
rc = mdb_put0(txn, MAIN_DBI, &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_cmp = NULL;
txn->mt_dbxs[txn->mt_numdbs].md_dcmp = NULL;
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_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;
}