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lmdb/libraries/libmdb/mdb.c

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#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 <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <openssl/sha.h>
#include "mdb.h"
#define DEBUG
#ifdef DEBUG
# define DPRINTF(...) do { fprintf(stderr, "%s:%d: ", __func__, __LINE__); \
fprintf(stderr, __VA_ARGS__); \
fprintf(stderr, "\n"); } while(0)
#else
# define DPRINTF(...)
#endif
#define PAGESIZE 4096
#define MDB_MINKEYS 4
#define MDB_MAGIC 0xBEEFC0DE
#define MDB_VERSION 1
#define MAXKEYSIZE 255
#define P_INVALID 0xFFFFFFFF
#define F_ISSET(w, f) (((w) & (f)) == (f))
typedef ulong pgno_t;
typedef uint16_t indx_t;
/* 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 */
pgno_t mp_pgno; /* page number */
#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_HEAD 0x10 /* header page */
#define P_DIRTY 0x20 /* dirty page */
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;
#define PAGEHDRSZ 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) (1000 * ((env)->me_head.mh_psize - PAGEHDRSZ - SIZELEFT(p)) / \
((env)->me_head.mh_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)
typedef struct MDB_head { /* header page content */
uint32_t mh_magic;
uint32_t mh_version;
uint32_t mh_flags;
uint32_t mh_psize; /* page size */
void *mh_address; /* address for fixed mapping */
size_t mh_mapsize; /* size of mmap region */
} MDB_head;
typedef struct MDB_rootstat {
pgno_t mr_root; /* page number of root page */
MDB_stat mr_stat;
} MDB_rootstat;
typedef struct MDB_meta { /* meta (footer) page content */
pgno_t mm_root; /* page number of root page */
MDB_stat mm_stat;
pgno_t mm_prev_meta; /* previous meta page number */
#define MDB_TOMBSTONE 0x01 /* file is replaced */
uint32_t mm_flags;
#define mm_revisions mm_stat.ms_revisions
#define mm_created_at mm_stat.ms_created_at
uint8_t mm_hash[SHA_DIGEST_LENGTH];
} MDB_meta;
typedef struct MDB_dhead { /* a dirty page */
SIMPLEQ_ENTRY(MDB_dpage) md_next; /* queue of dirty pages */
MDB_page *md_parent;
int md_pi; /* parent index */
int md_num;
} MDB_dhead;
typedef struct MDB_dpage {
MDB_dhead h;
MDB_page p;
} MDB_dpage;
SIMPLEQ_HEAD(dirty_queue, MDB_dpage);
typedef struct MDB_pageparent {
MDB_page *mp_page;
MDB_page *mp_parent;
int mp_pi;
} MDB_pageparent;
static MDB_dpage *mdb_newpage(MDB_txn *txn, MDB_page *parent, 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);
#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_cursor {
MDB_db *mc_db;
MDB_txn *mc_txn;
struct page_stack mc_stack; /* stack of parent pages */
short mc_initialized; /* 1 if initialized */
short mc_eof; /* 1 if end is reached */
};
#define METAHASHLEN offsetof(MDB_meta, mm_hash)
#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;
uint16_t mn_ksize; /* key size */
#define F_BIGDATA 0x01 /* data put on overflow page */
uint8_t mn_flags;
char mn_data[1];
} MDB_node;
struct MDB_txn {
pgno_t mt_root; /* current / new root page */
pgno_t mt_next_pgno; /* next unallocated page */
pgno_t mt_first_pgno;
MDB_env *mt_env;
struct dirty_queue *mt_dirty_queue; /* modified pages */
#define MDB_TXN_RDONLY 0x01 /* read-only transaction */
#define MDB_TXN_ERROR 0x02 /* an error has occurred */
unsigned int mt_flags;
};
/* Must be same as MDB_db, minus md_root/md_stat */
typedef struct MDB_db0 {
unsigned int md_flags;
MDB_cmp_func *md_cmp; /* user compare function */
MDB_rel_func *md_rel; /* user relocate function */
MDB_db *md_parent; /* parent tree */
MDB_env *md_env;
} MDB_db0;
struct MDB_db {
unsigned int md_flags;
MDB_cmp_func *md_cmp; /* user compare function */
MDB_rel_func *md_rel; /* user relocate function */
MDB_db *md_parent; /* parent tree */
MDB_env *md_env;
pgno_t md_root; /* page number of root page */
MDB_stat md_stat;
};
struct MDB_env {
int me_fd;
#define MDB_FIXPADDING 0x01 /* internal */
uint32_t me_flags;
char *me_path;
char *me_map;
MDB_head me_head;
MDB_db0 me_db; /* first DB, overlaps with meta */
MDB_meta me_meta;
MDB_txn *me_txn; /* current write transaction */
size_t me_mapsize;
off_t me_size; /* current file 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 */
#define MDB_MAXCACHE_DEF 1024 /* max number of pages to keep in cache */
static int mdb_search_page_root(MDB_db *db,
MDB_val *key,
MDB_cursor *cursor, int modify,
MDB_pageparent *mpp);
static int mdb_search_page(MDB_db *db,
MDB_txn *txn, MDB_val *key,
MDB_cursor *cursor, int modify,
MDB_pageparent *mpp);
static int mdbenv_write_header(MDB_env *env);
static int mdbenv_read_header(MDB_env *env);
static int mdb_check_meta_page(MDB_page *p);
static int mdbenv_read_meta(MDB_env *env, pgno_t *p_next);
static int mdbenv_write_meta(MDB_env *env, pgno_t root,
unsigned int flags);
static MDB_page *mdbenv_get_page(MDB_env *env, pgno_t pgno);
static MDB_node *mdb_search_node(MDB_db *db, MDB_page *mp,
MDB_val *key, int *exactp, unsigned int *kip);
static int mdb_add_node(MDB_db *bt, MDB_page *mp,
indx_t indx, MDB_val *key, MDB_val *data,
pgno_t pgno, uint8_t flags);
static void mdb_del_node(MDB_db *bt, MDB_page *mp,
indx_t indx);
static int mdb_read_data(MDB_db *bt, MDB_page *mp,
MDB_node *leaf, MDB_val *data);
static int mdb_rebalance(MDB_db *bt, MDB_pageparent *mp);
static int mdb_update_key(MDB_db *bt, MDB_page *mp,
indx_t indx, MDB_val *key);
static int mdb_move_node(MDB_db *bt,
MDB_pageparent *src, indx_t srcindx,
MDB_pageparent *dst, indx_t dstindx);
static int mdb_merge(MDB_db *bt, MDB_pageparent *src,
MDB_pageparent *dst);
static int mdb_split(MDB_db *bt, MDB_page **mpp,
unsigned int *newindxp, MDB_val *newkey,
MDB_val *newdata, pgno_t newpgno);
static MDB_dpage *mdbenv_new_page(MDB_env *env, 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_db *bt, MDB_page *mp,
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);
static int mdb_cursor_set(MDB_cursor *cursor,
MDB_val *key, MDB_val *data, int *exactp);
static int mdb_cursor_first(MDB_cursor *cursor,
MDB_val *key, MDB_val *data);
static size_t mdb_leaf_size(MDB_db *bt, MDB_val *key,
MDB_val *data);
static size_t mdb_branch_size(MDB_db *bt, MDB_val *key);
static pgno_t mdbenv_compact_tree(MDB_env *env, pgno_t pgno,
MDB_env *envc);
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)
{
if (n1 < n2) {
if (memcmp(s1, s2, n1) == 0)
return -1;
}
else if (n1 > n2) {
if (memcmp(s1, s2, n2) == 0)
return 1;
}
return memcmp(s1, s2, n1);
}
static int
memnrcmp(const void *s1, size_t n1, const void *s2, size_t n2)
{
const unsigned char *p1;
const unsigned char *p2;
if (n1 == 0)
return n2 == 0 ? 0 : -1;
if (n2 == 0)
return n1 == 0 ? 0 : 1;
p1 = (const unsigned char *)s1 + n1 - 1;
p2 = (const unsigned char *)s2 + n2 - 1;
while (*p1 == *p2) {
if (p1 == s1)
return (p2 == s2) ? 0 : -1;
if (p2 == s2)
return (p1 == p2) ? 0 : 1;
p1--;
p2--;
}
return *p1 - *p2;
}
int
mdb_cmp(MDB_db *db, const MDB_val *a, const MDB_val *b)
{
return db->md_cmp(a, b);
}
static int
_mdb_cmp(MDB_db *db, const MDB_val *key1, const MDB_val *key2)
{
if (F_ISSET(db->md_flags, MDB_REVERSEKEY))
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_newpage(MDB_txn *txn, MDB_page *parent, int parent_idx, int num)
{
MDB_dpage *dp;
if ((dp = malloc(txn->mt_env->me_head.mh_psize * num + sizeof(MDB_dhead))) == NULL)
return NULL;
dp->h.md_num = num;
dp->h.md_parent = parent;
dp->h.md_pi = parent_idx;
SIMPLEQ_INSERT_TAIL(txn->mt_dirty_queue, dp, h.md_next);
dp->p.mp_pgno = txn->mt_next_pgno;
txn->mt_next_pgno += num;
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)
{
int rc;
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;
DPRINTF("touching page %lu -> %lu", mp->mp_pgno, txn->mt_next_pgno);
if ((dp = mdb_newpage(txn, pp->mp_parent, pp->mp_pi, 1)) == NULL)
return ENOMEM;
pgno = dp->p.mp_pgno;
bcopy(mp, &dp->p, txn->mt_env->me_head.mh_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
mdbenv_sync(MDB_env *env)
{
int rc = 0;
if (!F_ISSET(env->me_flags, MDB_NOSYNC)) {
if (fsync(env->me_fd))
rc = errno;
}
return rc;
}
int
mdb_txn_begin(MDB_env *env, int rdonly, MDB_txn **ret)
{
MDB_txn *txn;
int rc;
if (!rdonly && env->me_txn != NULL) {
DPRINTF("write transaction already begun");
return EBUSY;
}
if ((txn = calloc(1, sizeof(*txn))) == NULL) {
DPRINTF("calloc: %s", strerror(errno));
return ENOMEM;
}
if (rdonly) {
txn->mt_flags |= MDB_TXN_RDONLY;
} else {
txn->mt_dirty_queue = calloc(1, sizeof(*txn->mt_dirty_queue));
if (txn->mt_dirty_queue == NULL) {
free(txn);
return ENOMEM;
}
SIMPLEQ_INIT(txn->mt_dirty_queue);
#if 0
DPRINTF("taking write lock on txn %p", txn);
if (flock(bt->fd, LOCK_EX | LOCK_NB) != 0) {
DPRINTF("flock: %s", strerror(errno));
errno = EBUSY;
free(txn->dirty_queue);
free(txn);
return NULL;
}
#endif
env->me_txn = txn;
}
txn->mt_env = env;
if ((rc = mdbenv_read_meta(env, &txn->mt_next_pgno)) != MDB_SUCCESS) {
mdb_txn_abort(txn);
return rc;
}
txn->mt_first_pgno = txn->mt_next_pgno;
txn->mt_root = env->me_meta.mm_root;
DPRINTF("begin transaction on mdbenv %p, root page %lu", env, txn->mt_root);
*ret = txn;
return MDB_SUCCESS;
}
void
mdb_txn_abort(MDB_txn *txn)
{
MDB_dpage *dp;
MDB_env *env;
if (txn == NULL)
return;
env = txn->mt_env;
DPRINTF("abort transaction on mdbenv %p, root page %lu", env, txn->mt_root);
if (!F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
/* Discard all dirty pages.
*/
while (!SIMPLEQ_EMPTY(txn->mt_dirty_queue)) {
dp = SIMPLEQ_FIRST(txn->mt_dirty_queue);
SIMPLEQ_REMOVE_HEAD(txn->mt_dirty_queue, h.md_next);
free(dp);
}
#if 0
DPRINTF("releasing write lock on txn %p", txn);
txn->bt->txn = NULL;
if (flock(txn->bt->fd, LOCK_UN) != 0) {
DPRINTF("failed to unlock fd %d: %s",
txn->bt->fd, strerror(errno));
}
#endif
free(txn->mt_dirty_queue);
}
if (txn == env->me_txn)
env->me_txn = NULL;
free(txn);
}
int
mdb_txn_commit(MDB_txn *txn)
{
int n, done;
ssize_t rc;
off_t size;
MDB_dpage *dp;
MDB_env *env;
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)) {
DPRINTF("attempt to commit read-only transaction");
mdb_txn_abort(txn);
return EPERM;
}
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 (SIMPLEQ_EMPTY(txn->mt_dirty_queue))
goto done;
if (F_ISSET(env->me_flags, MDB_FIXPADDING)) {
size = lseek(env->me_fd, 0, SEEK_END);
size += env->me_head.mh_psize - (size % env->me_head.mh_psize);
DPRINTF("extending to multiple of page size: %lu", size);
if (ftruncate(env->me_fd, size) != 0) {
n = errno;
DPRINTF("ftruncate: %s", strerror(errno));
mdb_txn_abort(txn);
return n;
}
env->me_flags ^= MDB_FIXPADDING;
}
DPRINTF("committing transaction on mdbenv %p, root page %lu",
env, txn->mt_root);
/* Commit up to MDB_COMMIT_PAGES dirty pages to disk until done.
*/
do {
n = 0;
done = 1;
SIMPLEQ_FOREACH(dp, txn->mt_dirty_queue, h.md_next) {
DPRINTF("committing page %lu", dp->p.mp_pgno);
iov[n].iov_len = env->me_head.mh_psize * dp->h.md_num;
iov[n].iov_base = &dp->p;
/* 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 != (ssize_t)env->me_head.mh_psize*n) {
n = errno;
if (rc > 0)
DPRINTF("short write, filesystem full?");
else
DPRINTF("writev: %s", strerror(errno));
mdb_txn_abort(txn);
return n;
}
/* Drop the dirty pages.
*/
while (!SIMPLEQ_EMPTY(txn->mt_dirty_queue)) {
dp = SIMPLEQ_FIRST(txn->mt_dirty_queue);
SIMPLEQ_REMOVE_HEAD(txn->mt_dirty_queue, h.md_next);
free(dp);
if (--n == 0)
break;
}
} while (!done);
if ((n = mdbenv_sync(env)) != 0 ||
(n = mdbenv_write_meta(env, txn->mt_root, 0)) != MDB_SUCCESS ||
(n = mdbenv_sync(env)) != 0) {
mdb_txn_abort(txn);
return n;
}
txn = NULL;
env->me_txn = NULL;
done:
mdb_txn_abort(txn);
return MDB_SUCCESS;
}
static int
mdbenv_write_header(MDB_env *env)
{
struct stat sb;
MDB_head *h;
MDB_page *p;
ssize_t rc;
unsigned int psize;
DPRINTF("writing header page");
assert(env != NULL);
psize = sysconf(_SC_PAGE_SIZE);
if ((p = calloc(1, psize)) == NULL)
return ENOMEM;
p->mp_flags = P_HEAD;
env->me_head.mh_psize = psize;
env->me_head.mh_flags = env->me_flags & 0xffff;
h = METADATA(p);
bcopy(&env->me_head, h, sizeof(*h));
rc = write(env->me_fd, p, env->me_head.mh_psize);
free(p);
if (rc != (ssize_t)env->me_head.mh_psize) {
int err = errno;
if (rc > 0)
DPRINTF("short write, filesystem full?");
return err;
}
return MDB_SUCCESS;
}
static int
mdbenv_read_header(MDB_env *env)
{
char page[PAGESIZE];
MDB_page *p;
MDB_head *h;
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_HEAD)) {
DPRINTF("page %lu not a header page", p->mp_pgno);
return EINVAL;
}
h = METADATA(p);
if (h->mh_magic != MDB_MAGIC) {
DPRINTF("header has invalid magic");
return EINVAL;
}
if (h->mh_version != MDB_VERSION) {
DPRINTF("database is version %u, expected version %u",
h->mh_version, MDB_VERSION);
return EINVAL;
}
bcopy(h, &env->me_head, sizeof(*h));
return 0;
}
static int
mdbenv_write_meta(MDB_env *env, pgno_t root, unsigned int flags)
{
MDB_dpage *dp;
MDB_meta *meta;
ssize_t rc;
DPRINTF("writing meta page for root page %lu", root);
assert(env != NULL);
assert(env->me_txn != NULL);
if ((dp = mdbenv_new_page(env, P_META, 1)) == NULL)
return ENOMEM;
env->me_meta.mm_prev_meta = env->me_meta.mm_root;
env->me_meta.mm_root = root;
env->me_meta.mm_flags = flags;
env->me_meta.mm_created_at = time(0);
env->me_meta.mm_revisions++;
SHA1((unsigned char *)&env->me_meta, METAHASHLEN, env->me_meta.mm_hash);
/* Copy the meta data changes to the new meta page. */
meta = METADATA(&dp->p);
bcopy(&env->me_meta, meta, sizeof(*meta));
rc = write(env->me_fd, &dp->p, env->me_head.mh_psize);
SIMPLEQ_REMOVE_HEAD(env->me_txn->mt_dirty_queue, h.md_next);
free(dp);
if (rc != (ssize_t)env->me_head.mh_psize) {
int err = errno;
if (rc > 0)
DPRINTF("short write, filesystem full?");
return err;
}
if ((env->me_size = lseek(env->me_fd, 0, SEEK_END)) == -1) {
DPRINTF("failed to update file size: %s", strerror(errno));
env->me_size = 0;
}
return MDB_SUCCESS;
}
/* Returns true if page p is a valid meta page, false otherwise.
*/
static int
mdb_check_meta_page(MDB_page *p)
{
MDB_meta *m;
unsigned char hash[SHA_DIGEST_LENGTH];
m = METADATA(p);
if (!F_ISSET(p->mp_flags, P_META)) {
DPRINTF("page %lu not a meta page", p->mp_pgno);
return EINVAL;
}
if (m->mm_root >= p->mp_pgno && m->mm_root != P_INVALID) {
DPRINTF("page %lu points to an invalid root page", p->mp_pgno);
return EINVAL;
}
SHA1((unsigned char *)m, METAHASHLEN, hash);
if (bcmp(hash, m->mm_hash, SHA_DIGEST_LENGTH) != 0) {
DPRINTF("page %lu has an invalid digest", p->mp_pgno);
return EINVAL;
}
return 0;
}
static int
mdbenv_read_meta(MDB_env *env, pgno_t *p_next)
{
MDB_page *mp;
MDB_meta *meta;
pgno_t meta_pgno, next_pgno;
off_t size;
assert(env != NULL);
if ((size = lseek(env->me_fd, 0, SEEK_END)) == -1)
goto fail;
DPRINTF("mdbenv_read_meta: size = %lu", size);
if (size < env->me_size) {
DPRINTF("file has shrunk!");
errno = EIO;
goto fail;
}
if (size == env->me_head.mh_psize) { /* there is only the header */
if (p_next != NULL)
*p_next = 1;
env->me_meta.mm_stat.ms_psize = env->me_head.mh_psize;
return MDB_SUCCESS; /* new file */
}
next_pgno = size / env->me_head.mh_psize;
if (next_pgno == 0) {
DPRINTF("corrupt file");
errno = EIO;
goto fail;
}
meta_pgno = next_pgno - 1;
if (size % env->me_head.mh_psize != 0) {
DPRINTF("filesize not a multiple of the page size!");
env->me_flags |= MDB_FIXPADDING;
next_pgno++;
}
if (p_next != NULL)
*p_next = next_pgno;
if (size == env->me_size) {
DPRINTF("size unchanged, keeping current meta page");
if (F_ISSET(env->me_meta.mm_flags, MDB_TOMBSTONE)) {
DPRINTF("file is dead");
errno = ESTALE;
return MDB_FAIL;
} else
return MDB_SUCCESS;
} else {
env->me_size = size;
}
while (meta_pgno > 0) {
if ((mp = mdbenv_get_page(env, meta_pgno)) == NULL)
break;
if (!mdb_check_meta_page(mp)) {
meta = METADATA(mp);
DPRINTF("flags = 0x%x", meta->mm_flags);
if (F_ISSET(meta->mm_flags, MDB_TOMBSTONE)) {
DPRINTF("file is dead");
errno = ESTALE;
return MDB_FAIL;
} else {
/* Make copy of last meta page. */
bcopy(meta, &env->me_meta, sizeof(env->me_meta));
return MDB_SUCCESS;
}
}
--meta_pgno; /* scan backwards to first valid meta page */
}
errno = EIO;
fail:
if (p_next != NULL)
*p_next = P_INVALID;
return MDB_FAIL;
}
int
mdbenv_create(MDB_env **env, size_t size)
{
MDB_env *e;
e = calloc(1, sizeof(*e));
if (!e) return ENOMEM;
e->me_head.mh_magic = MDB_MAGIC;
e->me_head.mh_version = MDB_VERSION;
e->me_mapsize = e->me_head.mh_mapsize = size;
e->me_db.md_env = e;
*env = e;
return MDB_SUCCESS;
}
int
mdbenv_open2(MDB_env *env, unsigned int flags)
{
int i, newenv = 0;
i = fcntl(env->me_fd, F_GETFL, 0);
if (fcntl(env->me_fd, F_SETFL, i | O_APPEND) == -1)
return errno;
env->me_flags = flags;
env->me_flags &= ~MDB_FIXPADDING;
env->me_meta.mm_root = P_INVALID;
if ((i = mdbenv_read_header(env)) != 0) {
if (i != ENOENT)
return i;
DPRINTF("new mdbenv");
newenv = 1;
}
if (!env->me_mapsize)
env->me_mapsize = env->me_head.mh_mapsize;
i = MAP_SHARED;
if (env->me_head.mh_address && (flags & MDB_FIXEDMAP))
i |= MAP_FIXED;
env->me_map = mmap(env->me_head.mh_address, env->me_mapsize, PROT_READ, i,
env->me_fd, 0);
if (env->me_map == MAP_FAILED)
return errno;
if (newenv) {
env->me_head.mh_mapsize = env->me_mapsize;
if (flags & MDB_FIXEDMAP)
env->me_head.mh_address = env->me_map;
i = mdbenv_write_header(env);
if (i != MDB_SUCCESS) {
munmap(env->me_map, env->me_mapsize);
return i;
}
}
if ((i = mdbenv_read_meta(env, NULL)) != 0)
return i;
DPRINTF("opened database version %u, pagesize %u",
env->me_head.mh_version, env->me_head.mh_psize);
DPRINTF("timestamp: %s", ctime(&env->me_meta.mm_created_at));
DPRINTF("depth: %u", env->me_meta.mm_stat.ms_depth);
DPRINTF("entries: %lu", env->me_meta.mm_stat.ms_entries);
DPRINTF("revisions: %lu", env->me_meta.mm_stat.ms_revisions);
DPRINTF("branch pages: %lu", env->me_meta.mm_stat.ms_branch_pages);
DPRINTF("leaf pages: %lu", env->me_meta.mm_stat.ms_leaf_pages);
DPRINTF("overflow pages: %lu", env->me_meta.mm_stat.ms_overflow_pages);
DPRINTF("root: %lu", env->me_meta.mm_root);
DPRINTF("previous me_meta.me_page: %lu", env->me_meta.mm_prev_meta);
return MDB_SUCCESS;
}
int
mdbenv_open(MDB_env *env, const char *path, unsigned int flags, mode_t mode)
{
int oflags, rc;
if (F_ISSET(flags, MDB_RDONLY))
oflags = O_RDONLY;
else
oflags = O_RDWR | O_CREAT | O_APPEND;
if ((env->me_fd = open(path, oflags, mode)) == -1)
return errno;
if ((rc = mdbenv_open2(env, flags)) != MDB_SUCCESS) {
close(env->me_fd);
env->me_fd = -1;
} else {
env->me_path = strdup(path);
DPRINTF("opened dbenv %p", env);
}
return rc;
}
void
mdbenv_close(MDB_env *env)
{
if (env == NULL)
return;
free(env->me_path);
if (env->me_map) {
munmap(env->me_map, env->me_mapsize);
}
close(env->me_fd);
}
/* 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_db *bt, 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 %lu keys in %s page %lu",
NUMKEYS(mp),
IS_LEAF(mp) ? "leaf" : "branch",
mp->mp_pgno);
assert(NUMKEYS(mp) > 0);
bzero(&nodekey, 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 (bt->md_cmp)
rc = bt->md_cmp(key, &nodekey);
else
rc = _mdb_cmp(bt, 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, 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, cursor);
if ((ppage = calloc(1, sizeof(*ppage))) == NULL)
return NULL;
ppage->mp_page = mp;
CURSOR_PUSH(cursor, ppage);
return ppage;
}
static MDB_page *
mdbenv_get_page(MDB_env *env, pgno_t pgno)
{
MDB_page *p = NULL;
MDB_txn *txn = env->me_txn;
if (txn && pgno >= txn->mt_first_pgno &&
!SIMPLEQ_EMPTY(txn->mt_dirty_queue)) {
MDB_dpage *dp;
SIMPLEQ_FOREACH(dp, txn->mt_dirty_queue, h.md_next) {
if (dp->p.mp_pgno == pgno) {
p = &dp->p;
break;
}
}
} else {
p = (MDB_page *)(env->me_map + env->me_head.mh_psize * pgno);
}
return p;
}
static int
mdb_search_page_root(MDB_db *bt, 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 MDB_FAIL;
while (IS_BRANCH(mp)) {
unsigned int i = 0;
MDB_node *node;
DPRINTF("branch page %lu has %lu 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 {
int exact;
node = mdb_search_node(bt, 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 >= 0 && i < NUMKEYS(mp));
node = NODEPTR(mp, i);
if (cursor)
CURSOR_TOP(cursor)->mp_ki = i;
mpp->mp_parent = mp;
if ((mp = mdbenv_get_page(bt->md_env, NODEPGNO(node))) == NULL)
return MDB_FAIL;
mpp->mp_pi = i;
mpp->mp_page = mp;
if (cursor && cursor_push_page(cursor, mp) == NULL)
return MDB_FAIL;
if (modify && (rc = mdb_touch(bt->md_env->me_txn, mpp)))
return rc;
mp = mpp->mp_page;
}
if (!IS_LEAF(mp)) {
DPRINTF("internal error, index points to a %02X page!?",
mp->mp_flags);
return MDB_FAIL;
}
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_db *db, MDB_txn *txn, MDB_val *key,
MDB_cursor *cursor, int modify, MDB_pageparent *mpp)
{
int rc;
pgno_t root;
/* Can't modify pages outside a transaction. */
if (txn == NULL && modify) {
return EINVAL;
}
/* 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 (txn == NULL) {
if ((rc = mdbenv_read_meta(db->md_env, NULL)) != MDB_SUCCESS)
return rc;
root = db->md_env->me_meta.mm_root;
} else if (F_ISSET(txn->mt_flags, MDB_TXN_ERROR)) {
DPRINTF("transaction has failed, must abort");
return EINVAL;
} else
root = txn->mt_root;
if (root == P_INVALID) { /* Tree is empty. */
DPRINTF("tree is empty");
return ENOENT;
}
if ((mpp->mp_page = mdbenv_get_page(db->md_env, root)) == NULL)
return MDB_FAIL;
DPRINTF("root page has flags 0x%X", mpp->mp_page->mp_flags);
if (modify && !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_root = mpp->mp_page->mp_pgno;
}
return mdb_search_page_root(db, key, cursor, modify, mpp);
}
static int
mdb_read_data(MDB_db *db, MDB_page *mp, MDB_node *leaf,
MDB_val *data)
{
MDB_page *omp; /* overflow mpage */
size_t psz;
size_t max;
size_t sz = 0;
pgno_t pgno;
bzero(data, sizeof(*data));
max = db->md_env->me_head.mh_psize - PAGEHDRSZ;
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;
bcopy(NODEDATA(leaf), &pgno, sizeof(pgno));
if ((omp = mdbenv_get_page(db->md_env, pgno)) == NULL) {
DPRINTF("read overflow page %lu failed", pgno);
return MDB_FAIL;
}
data->mv_data = omp;
return MDB_SUCCESS;
}
int
mdb_get(MDB_db *db, MDB_txn *txn,
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 (db == NULL)
return EINVAL;
if (txn != NULL && db->md_env != txn->mt_env) {
return EINVAL;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
if ((rc = mdb_search_page(db, txn, key, NULL, 0, &mpp)) != MDB_SUCCESS)
return rc;
leaf = mdb_search_node(db, mpp.mp_page, key, &exact, NULL);
if (leaf && exact)
rc = mdb_read_data(db, mpp.mp_page, leaf, data);
else {
rc = ENOENT;
}
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 ENOENT; /* 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));
#if 0
indx = NODEPTR(parent->mp_page, parent->mp_ki);
if ((mp = mdbenv_get_page(cursor->bt, indx->n_pgno)) == NULL)
return MDB_FAIL;
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_db *bt, MDB_page *mp, 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_ppage *top;
MDB_page *mp;
MDB_node *leaf;
if (cursor->mc_eof) {
return ENOENT;
}
assert(cursor->mc_initialized);
top = CURSOR_TOP(cursor);
mp = top->mp_page;
DPRINTF("cursor_next: top page is %lu in cursor %p", mp->mp_pgno, 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 ENOENT;
}
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 %lu keys, key index %u",
mp->mp_pgno, NUMKEYS(mp), top->mp_ki);
assert(IS_LEAF(mp));
leaf = NODEPTR(mp, top->mp_ki);
if (data && mdb_read_data(cursor->mc_db, mp, leaf, data) != MDB_SUCCESS)
return MDB_FAIL;
return mdb_set_key(cursor->mc_db, mp, leaf, key);
}
static int
mdb_cursor_set(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
int *exactp)
{
int rc;
MDB_node *leaf;
MDB_ppage *top;
MDB_pageparent mpp;
assert(cursor);
assert(key);
assert(key->mv_size > 0);
rc = mdb_search_page(cursor->mc_db, cursor->mc_txn, 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_db, mpp.mp_page, key, exactp, &top->mp_ki);
if (exactp != NULL && !*exactp) {
/* MDB_CURSOR_EXACT specified and not an exact match. */
return ENOENT;
}
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 && (rc = mdb_read_data(cursor->mc_db, mpp.mp_page, leaf, data)) != MDB_SUCCESS)
return rc;
rc = mdb_set_key(cursor->mc_db, mpp.mp_page, 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;
rc = mdb_search_page(cursor->mc_db, cursor->mc_txn, 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 && (rc = mdb_read_data(cursor->mc_db, mpp.mp_page, leaf, data)) != MDB_SUCCESS)
return rc;
return mdb_set_key(cursor->mc_db, mpp.mp_page, 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_CURSOR:
case MDB_CURSOR_EXACT:
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
if (key == NULL || key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
rc = EINVAL;
} else if (op == MDB_CURSOR_EXACT)
rc = mdb_cursor_set(cursor, key, data, &exact);
else
rc = mdb_cursor_set(cursor, key, data, NULL);
break;
case MDB_NEXT:
if (!cursor->mc_initialized)
rc = mdb_cursor_first(cursor, key, data);
else
rc = mdb_cursor_next(cursor, key, data);
break;
case MDB_FIRST:
while (CURSOR_TOP(cursor) != NULL)
cursor_pop_page(cursor);
rc = mdb_cursor_first(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 *
mdbenv_new_page(MDB_env *env, uint32_t flags, int num)
{
MDB_dpage *dp;
assert(env != NULL);
assert(env->me_txn != NULL);
DPRINTF("allocating new mpage %lu, page size %u",
env->me_txn->mt_next_pgno, env->me_head.mh_psize);
if ((dp = mdb_newpage(env->me_txn, NULL, 0, num)) == NULL)
return NULL;
dp->p.mp_flags = flags;
dp->p.mp_lower = PAGEHDRSZ;
dp->p.mp_upper = env->me_head.mh_psize;
if (IS_BRANCH(&dp->p))
env->me_meta.mm_stat.ms_branch_pages++;
else if (IS_LEAF(&dp->p))
env->me_meta.mm_stat.ms_leaf_pages++;
else if (IS_OVERFLOW(&dp->p)) {
env->me_meta.mm_stat.ms_overflow_pages += num;
dp->p.mp_pages = num;
}
return dp;
}
static size_t
mdb_leaf_size(MDB_db *db, MDB_val *key, MDB_val *data)
{
size_t sz;
sz = LEAFSIZE(key, data);
if (data->mv_size >= db->md_env->me_head.mh_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_db *db, MDB_val *key)
{
size_t sz;
sz = INDXSIZE(key);
if (sz >= db->md_env->me_head.mh_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_db *db, 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);
node_size += data->mv_size;
if (F_ISSET(flags, F_BIGDATA)) {
/* Data already on overflow page. */
node_size -= data->mv_size - sizeof(pgno_t);
} else if (data->mv_size >= db->md_env->me_head.mh_psize / MDB_MINKEYS) {
int ovpages = PAGEHDRSZ + data->mv_size + db->md_env->me_head.mh_psize - 1;
ovpages /= db->md_env->me_head.mh_psize;
/* Put data on overflow page. */
DPRINTF("data size is %zu, put on overflow page",
data->mv_size);
node_size -= data->mv_size - sizeof(pgno_t);
if ((ofp = mdbenv_new_page(db->md_env, P_OVERFLOW, ovpages)) == NULL)
return MDB_FAIL;
DPRINTF("allocated overflow page %lu", ofp->p.mp_pgno);
flags |= F_BIGDATA;
}
}
if (node_size + sizeof(indx_t) > SIZELEFT(mp)) {
DPRINTF("not enough room in page %lu, got %lu 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)
bcopy(key->mv_data, NODEKEY(node), key->mv_size);
if (IS_LEAF(mp)) {
assert(key);
if (ofp == NULL) {
if (F_ISSET(flags, F_BIGDATA))
bcopy(data->mv_data, node->mn_data + key->mv_size,
sizeof(pgno_t));
else
bcopy(data->mv_data, node->mn_data + key->mv_size,
data->mv_size);
} else {
bcopy(&ofp->p.mp_pgno, node->mn_data + key->mv_size,
sizeof(pgno_t));
bcopy(data->mv_data, METADATA(&ofp->p), data->mv_size);
}
}
return MDB_SUCCESS;
}
static void
mdb_del_node(MDB_db *db, 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;
bcopy(base, base + sz, ptr - mp->mp_upper);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += sz;
}
int
mdb_cursor_open(MDB_db *db, MDB_txn *txn, MDB_cursor **ret)
{
MDB_cursor *cursor;
if (db == NULL || ret == NULL)
return EINVAL;
if (txn != NULL && db->md_env != txn->mt_env) {
return EINVAL;
}
if ((cursor = calloc(1, sizeof(*cursor))) != NULL) {
SLIST_INIT(&cursor->mc_stack);
cursor->mc_db = db;
cursor->mc_txn = txn;
}
*ret = cursor;
return MDB_SUCCESS;
}
void
mdb_cursor_close(MDB_cursor *cursor)
{
if (cursor != NULL) {
while (!CURSOR_EMPTY(cursor))
cursor_pop_page(cursor);
/* btree_close(cursor->bt); */
free(cursor);
}
}
static int
mdb_update_key(MDB_db *db, 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;
bcopy(base, base - delta, len);
mp->mp_upper -= delta;
node = NODEPTR(mp, indx);
node->mn_ksize = key->mv_size;
}
bcopy(key->mv_data, NODEKEY(node), key->mv_size);
return MDB_SUCCESS;
}
/* Move a node from src to dst.
*/
static int
mdb_move_node(MDB_db *bt, 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(bt->md_env->me_txn, src)) ||
(rc = mdb_touch(bt->md_env->me_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(bt, 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(bt, 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(bt, 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(bt, 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(bt, 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(bt, dst->mp_page, 0, &nullkey) == MDB_SUCCESS);
}
return MDB_SUCCESS;
}
static int
mdb_merge(MDB_db *bt, 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(src->mp_parent); /* can't merge root page */
assert(dst->mp_parent);
assert(bt->md_env->me_txn != NULL);
/* Mark src and dst as dirty. */
if ((rc = mdb_touch(bt->md_env->me_txn, src)) ||
(rc = mdb_touch(bt->md_env->me_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(bt, 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 %lu keys (%.1f%% filled)",
dst->mp_page->mp_pgno, NUMKEYS(dst->mp_page), (float)PAGEFILL(bt->md_env, dst->mp_page) / 10);
/* Unlink the src page from parent.
*/
mdb_del_node(bt, src->mp_parent, src->mp_pi);
if (src->mp_pi == 0) {
key.mv_size = 0;
if ((rc = mdb_update_key(bt, src->mp_parent, 0, &key)) != MDB_SUCCESS)
return rc;
}
if (IS_LEAF(src->mp_page))
bt->md_env->me_meta.mm_stat.ms_leaf_pages--;
else
bt->md_env->me_meta.mm_stat.ms_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(bt, &mpp);
}
#define FILL_THRESHOLD 250
static int
mdb_rebalance(MDB_db *db, MDB_pageparent *mpp)
{
MDB_node *node;
MDB_page *root;
MDB_pageparent npp;
indx_t si = 0, di = 0;
assert(db != NULL);
assert(db->md_env->me_txn != NULL);
assert(mpp != NULL);
DPRINTF("rebalancing %s page %lu (has %lu keys, %.1f%% full)",
IS_LEAF(mpp->mp_page) ? "leaf" : "branch",
mpp->mp_page->mp_pgno, NUMKEYS(mpp->mp_page), (float)PAGEFILL(db->md_env, mpp->mp_page) / 10);
if (PAGEFILL(db->md_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");
db->md_env->me_txn->mt_root = P_INVALID;
db->md_env->me_meta.mm_stat.ms_depth--;
db->md_env->me_meta.mm_stat.ms_leaf_pages--;
} else if (IS_BRANCH(mpp->mp_page) && NUMKEYS(mpp->mp_page) == 1) {
DPRINTF("collapsing root page!");
db->md_env->me_txn->mt_root = NODEPGNO(NODEPTR(mpp->mp_page, 0));
if ((root = mdbenv_get_page(db->md_env, db->md_env->me_txn->mt_root)) == NULL)
return MDB_FAIL;
db->md_env->me_meta.mm_stat.ms_depth--;
db->md_env->me_meta.mm_stat.ms_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 = mdbenv_get_page(db->md_env, NODEPGNO(node))) == NULL)
return MDB_FAIL;
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 = mdbenv_get_page(db->md_env, NODEPGNO(node))) == NULL)
return MDB_FAIL;
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 (%lu keys, %.1f%% full)",
npp.mp_page->mp_pgno, NUMKEYS(npp.mp_page), (float)PAGEFILL(db->md_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(db->md_env, npp.mp_page) >= FILL_THRESHOLD && NUMKEYS(npp.mp_page) >= 2)
return mdb_move_node(db, &npp, si, mpp, di);
else { /* FIXME: if (has_enough_room()) */
if (mpp->mp_pi == 0)
return mdb_merge(db, &npp, mpp);
else
return mdb_merge(db, mpp, &npp);
}
}
int
mdb_del(MDB_db *bt, MDB_txn *txn,
MDB_val *key, MDB_val *data)
{
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 (bt == NULL || txn == NULL)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
return EINVAL;
}
if (bt->md_env->me_txn != txn) {
return EINVAL;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
if ((rc = mdb_search_page(bt, txn, key, NULL, 1, &mpp)) != MDB_SUCCESS)
return rc;
leaf = mdb_search_node(bt, mpp.mp_page, key, &exact, &ki);
if (leaf == NULL || !exact) {
return ENOENT;
}
if (data && (rc = mdb_read_data(bt, NULL, leaf, data)) != MDB_SUCCESS)
return rc;
mdb_del_node(bt, mpp.mp_page, ki);
bt->md_env->me_meta.mm_stat.ms_entries--;
rc = mdb_rebalance(bt, &mpp);
if (rc != MDB_SUCCESS)
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
}
/* 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_db *bt, 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_page *pright, *p;
MDB_val sepkey, rkey, rdata;
MDB_page *copy;
MDB_dpage *mdp, *rdp, *pdp;
MDB_dhead *dh;
assert(bt != NULL);
assert(bt->md_env != 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 = mdbenv_new_page(bt->md_env, P_BRANCH, 1)) == NULL)
return MDB_FAIL;
mdp->h.md_pi = 0;
mdp->h.md_parent = &pdp->p;
bt->md_env->me_txn->mt_root = pdp->p.mp_pgno;
DPRINTF("root split! new root = %lu", pdp->p.mp_pgno);
bt->md_env->me_meta.mm_stat.ms_depth++;
/* Add left (implicit) pointer. */
if (mdb_add_node(bt, &pdp->p, 0, NULL, NULL,
mdp->p.mp_pgno, 0) != MDB_SUCCESS)
return MDB_FAIL;
} else {
DPRINTF("parent branch page is %lu", mdp->h.md_parent->mp_pgno);
}
/* Create a right sibling. */
if ((rdp = mdbenv_new_page(bt->md_env, mdp->p.mp_flags, 1)) == NULL)
return MDB_FAIL;
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(bt->md_env->me_head.mh_psize)) == NULL)
return MDB_FAIL;
bcopy(&mdp->p, copy, bt->md_env->me_head.mh_psize);
bzero(&mdp->p.mp_ptrs, bt->md_env->me_head.mh_psize - PAGEHDRSZ);
mdp->p.mp_lower = PAGEHDRSZ;
mdp->p.mp_upper = bt->md_env->me_head.mh_psize;
split_indx = NUMKEYS(copy) / 2 + 1;
/* First find the separating key between the split pages.
*/
bzero(&sepkey, 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(bt, &sepkey)) {
rc = mdb_split(bt, &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(bt, rdp->h.md_parent, rdp->h.md_pi,
&sepkey, NULL, rdp->p.mp_pgno, 0);
}
if (rc != MDB_SUCCESS) {
free(copy);
return MDB_FAIL;
}
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(bt, &pdp->p, j, &rkey, &rdata, pgno,flags);
}
free(copy);
return rc;
}
int
mdb_put(MDB_db *bt, MDB_txn *txn,
MDB_val *key, MDB_val *data, unsigned int flags)
{
int rc = MDB_SUCCESS, exact;
unsigned int ki;
MDB_node *leaf;
MDB_pageparent mpp;
assert(key != NULL);
assert(data != NULL);
if (bt == NULL || txn == NULL)
return EINVAL;
if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) {
return EINVAL;
}
if (bt->md_env->me_txn != txn) {
return EINVAL;
}
if (key->mv_size == 0 || key->mv_size > MAXKEYSIZE) {
return EINVAL;
}
DPRINTF("==> put key %.*s, size %zu, data size %zu",
(int)key->mv_size, (char *)key->mv_data, key->mv_size, data->mv_size);
rc = mdb_search_page(bt, txn, key, NULL, 1, &mpp);
if (rc == MDB_SUCCESS) {
leaf = mdb_search_node(bt, mpp.mp_page, key, &exact, &ki);
if (leaf && exact) {
if (F_ISSET(flags, MDB_NOOVERWRITE)) {
DPRINTF("duplicate key %.*s",
(int)key->mv_size, (char *)key->mv_data);
return EEXIST;
}
mdb_del_node(bt, 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 == ENOENT) {
MDB_dpage *dp;
/* new file, just write a root leaf page */
DPRINTF("allocating new root leaf page");
if ((dp = mdbenv_new_page(bt->md_env, P_LEAF, 1)) == NULL) {
return ENOMEM;
}
mpp.mp_page = &dp->p;
txn->mt_root = mpp.mp_page->mp_pgno;
bt->md_env->me_meta.mm_stat.ms_depth++;
ki = 0;
}
else
goto done;
assert(IS_LEAF(mpp.mp_page));
DPRINTF("there are %lu keys, should insert new key at index %i",
NUMKEYS(mpp.mp_page), ki);
if (SIZELEFT(mpp.mp_page) < mdb_leaf_size(bt, key, data)) {
rc = mdb_split(bt, &mpp.mp_page, &ki, key, data, P_INVALID);
} else {
/* There is room already in this leaf page. */
rc = mdb_add_node(bt, mpp.mp_page, ki, key, data, 0, 0);
}
if (rc != MDB_SUCCESS)
txn->mt_flags |= MDB_TXN_ERROR;
else
bt->md_env->me_meta.mm_stat.ms_entries++;
done:
return rc;
}
static pgno_t
mdbenv_compact_tree(MDB_env *env, pgno_t pgno, MDB_env *envc)
{
ssize_t rc;
indx_t i;
pgno_t *pnext, next;
MDB_node *node;
MDB_page *p;
MDB_page *mp;
/* Get the page and make a copy of it.
*/
if ((mp = mdbenv_get_page(env, pgno)) == NULL)
return P_INVALID;
if ((p = malloc(env->me_head.mh_psize)) == NULL)
return P_INVALID;
bcopy(mp, p, env->me_head.mh_psize);
/* Go through all nodes in the (copied) page and update the
* page pointers.
*/
if (F_ISSET(p->mp_flags, P_BRANCH)) {
for (i = 0; i < NUMKEYS(p); i++) {
node = NODEPTR(p, i);
node->mn_pgno = mdbenv_compact_tree(env, node->mn_pgno, envc);
if (node->mn_pgno == P_INVALID) {
free(p);
return P_INVALID;
}
}
} else if (F_ISSET(p->mp_flags, P_LEAF)) {
for (i = 0; i < NUMKEYS(p); i++) {
node = NODEPTR(p, i);
if (F_ISSET(node->mn_flags, F_BIGDATA)) {
bcopy(NODEDATA(node), &next, sizeof(next));
next = mdbenv_compact_tree(env, next, envc);
if (next == P_INVALID) {
free(p);
return P_INVALID;
}
bcopy(&next, NODEDATA(node), sizeof(next));
}
}
} else if (F_ISSET(p->mp_flags, P_OVERFLOW)) {
; /* handled below */
} else
assert(0);
pgno = p->mp_pgno = envc->me_txn->mt_next_pgno++;
rc = write(envc->me_fd, p, env->me_head.mh_psize);
free(p);
if (rc != (ssize_t)env->me_head.mh_psize)
return P_INVALID;
if (F_ISSET(mp->mp_flags, P_OVERFLOW)) {
if (mp->mp_pages > 1) {
size_t len = (mp->mp_pages-1) * env->me_head.mh_psize;
envc->me_txn->mt_next_pgno += mp->mp_pages-1;
rc = write(envc->me_fd, mp+1, len);
if (rc != len)
return P_INVALID;
}
}
return pgno;
}
int
mdbenv_compact(MDB_env *env)
{
char *compact_path = NULL;
MDB_env *envc;
MDB_txn *txn, *txnc = NULL;
int fd, rc;
pgno_t root;
assert(env != NULL);
if (env->me_path == NULL) {
return EINVAL;
}
DPRINTF("compacting mdbenv %p with path %s", env, env->me_path);
rc = mdb_txn_begin(env, 0, &txn);
if (rc) return rc;
asprintf(&compact_path, "%s.compact.XXXXXX", env->me_path);
fd = mkstemp(compact_path);
if (fd == -1) {
rc = errno;
free(compact_path);
mdb_txn_abort(txn);
return rc;
}
rc = mdbenv_create(&envc, env->me_mapsize);
if (rc) goto failed;
envc->me_fd = fd;
rc = mdbenv_open2(envc, env->me_flags);
if (rc) goto failed;
bcopy(&env->me_meta, &envc->me_meta, sizeof(env->me_meta));
envc->me_meta.mm_stat.ms_revisions = 0;
rc = mdb_txn_begin(envc, 0, &txnc);
if (rc) goto failed;
if (env->me_meta.mm_root != P_INVALID) {
root = mdbenv_compact_tree(env, env->me_meta.mm_root, envc);
if (root == P_INVALID)
goto failed;
if ((rc = mdbenv_write_meta(envc, root, 0)) != MDB_SUCCESS)
goto failed;
}
fsync(fd);
DPRINTF("renaming %s to %s", compact_path, env->me_path);
if (rename(compact_path, env->me_path) != 0) {
rc = errno;
goto failed;
}
/* Write a "tombstone" meta page so other processes can pick up
* the change and re-open the file.
*/
if (mdbenv_write_meta(env, P_INVALID, MDB_TOMBSTONE) != MDB_SUCCESS)
goto failed;
mdb_txn_abort(txn);
mdb_txn_abort(txnc);
free(compact_path);
mdbenv_close(envc);
return 0;
failed:
mdb_txn_abort(txn);
mdb_txn_abort(txnc);
unlink(compact_path);
free(compact_path);
mdbenv_close(envc);
return rc;
}
int
mdbenv_get_flags(MDB_env *env, unsigned int *arg)
{
if (!env || !arg)
return EINVAL;
*arg = (env->me_flags & ~MDB_FIXPADDING);
return MDB_SUCCESS;
}
int
mdbenv_get_path(MDB_env *env, const char **arg)
{
if (!env || !arg)
return EINVAL;
*arg = env->me_path;
return MDB_SUCCESS;
}
int
mdbenv_stat(MDB_env *env, MDB_stat **arg)
{
if (env == NULL || arg == NULL)
return EINVAL;
*arg = &env->me_meta.mm_stat;
return MDB_SUCCESS;
}
int mdb_open(MDB_env *env, MDB_txn *txn, const char *name, unsigned int flags, MDB_db **db)
{
if (!name) {
*db = (MDB_db *)&env->me_db;
return MDB_SUCCESS;
}
return EINVAL;
}
int mdb_stat(MDB_db *db, MDB_stat **arg)
{
if (db == NULL || arg == NULL)
return EINVAL;
*arg = &db->md_stat;
return MDB_SUCCESS;
}
void mdb_close(MDB_db *db)
{
}