+++ /dev/null
- /*
- Unix SMB/CIFS implementation.
-
- trivial database library
-
- Copyright (C) Andrew Tridgell 1999-2005
- Copyright (C) Paul `Rusty' Russell 2000
- Copyright (C) Jeremy Allison 2000-2003
-
- ** NOTE! The following LGPL license applies to the tdb
- ** library. This does NOT imply that all of Samba is released
- ** under the LGPL
-
- This library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 3 of the License, or (at your option) any later version.
-
- This library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with this library; if not, see <http://www.gnu.org/licenses/>.
-*/
-
-#include "private.h"
-#include <assert.h>
-#include <ccan/build_assert/build_assert.h>
-
-/* If we were threaded, we could wait for unlock, but we're not, so fail. */
-enum TDB_ERROR owner_conflict(struct tdb_context *tdb, const char *call)
-{
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "%s: lock owned by another tdb in this process.",
- call);
-}
-
-/* If we fork, we no longer really own locks. */
-bool check_lock_pid(struct tdb_context *tdb, const char *call, bool log)
-{
- /* No locks? No problem! */
- if (tdb->file->allrecord_lock.count == 0
- && tdb->file->num_lockrecs == 0) {
- return true;
- }
-
- /* No fork? No problem! */
- if (tdb->file->locker == getpid()) {
- return true;
- }
-
- if (log) {
- tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "%s: fork() detected after lock acquisition!"
- " (%u vs %u)", call, tdb->file->locker, getpid());
- }
- return false;
-}
-
-int tdb_fcntl_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
- void *unused)
-{
- struct flock fl;
- int ret;
-
- do {
- fl.l_type = rw;
- fl.l_whence = SEEK_SET;
- fl.l_start = off;
- fl.l_len = len;
-
- if (waitflag)
- ret = fcntl(fd, F_SETLKW, &fl);
- else
- ret = fcntl(fd, F_SETLK, &fl);
- } while (ret != 0 && errno == EINTR);
- return ret;
-}
-
-int tdb_fcntl_unlock(int fd, int rw, off_t off, off_t len, void *unused)
-{
- struct flock fl;
- int ret;
-
- do {
- fl.l_type = F_UNLCK;
- fl.l_whence = SEEK_SET;
- fl.l_start = off;
- fl.l_len = len;
-
- ret = fcntl(fd, F_SETLKW, &fl);
- } while (ret != 0 && errno == EINTR);
- return ret;
-}
-
-static int lock(struct tdb_context *tdb,
- int rw, off_t off, off_t len, bool waitflag)
-{
- int ret;
- if (tdb->file->allrecord_lock.count == 0
- && tdb->file->num_lockrecs == 0) {
- tdb->file->locker = getpid();
- }
-
- tdb->stats.lock_lowlevel++;
- ret = tdb->lock_fn(tdb->file->fd, rw, off, len, waitflag,
- tdb->lock_data);
- if (!waitflag) {
- tdb->stats.lock_nonblock++;
- if (ret != 0)
- tdb->stats.lock_nonblock_fail++;
- }
- return ret;
-}
-
-static int unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
-{
-#if 0 /* Check they matched up locks and unlocks correctly. */
- char line[80];
- FILE *locks;
- bool found = false;
-
- locks = fopen("/proc/locks", "r");
-
- while (fgets(line, 80, locks)) {
- char *p;
- int type, start, l;
-
- /* eg. 1: FLOCK ADVISORY WRITE 2440 08:01:2180826 0 EOF */
- p = strchr(line, ':') + 1;
- if (strncmp(p, " POSIX ADVISORY ", strlen(" POSIX ADVISORY ")))
- continue;
- p += strlen(" FLOCK ADVISORY ");
- if (strncmp(p, "READ ", strlen("READ ")) == 0)
- type = F_RDLCK;
- else if (strncmp(p, "WRITE ", strlen("WRITE ")) == 0)
- type = F_WRLCK;
- else
- abort();
- p += 6;
- if (atoi(p) != getpid())
- continue;
- p = strchr(strchr(p, ' ') + 1, ' ') + 1;
- start = atoi(p);
- p = strchr(p, ' ') + 1;
- if (strncmp(p, "EOF", 3) == 0)
- l = 0;
- else
- l = atoi(p) - start + 1;
-
- if (off == start) {
- if (len != l) {
- fprintf(stderr, "Len %u should be %u: %s",
- (int)len, l, line);
- abort();
- }
- if (type != rw) {
- fprintf(stderr, "Type %s wrong: %s",
- rw == F_RDLCK ? "READ" : "WRITE", line);
- abort();
- }
- found = true;
- break;
- }
- }
-
- if (!found) {
- fprintf(stderr, "Unlock on %u@%u not found!",
- (int)off, (int)len);
- abort();
- }
-
- fclose(locks);
-#endif
-
- return tdb->unlock_fn(tdb->file->fd, rw, off, len, tdb->lock_data);
-}
-
-/* a byte range locking function - return 0 on success
- this functions locks len bytes at the specified offset.
-
- note that a len of zero means lock to end of file
-*/
-enum TDB_ERROR tdb_brlock(struct tdb_context *tdb,
- int rw_type, tdb_off_t offset, tdb_off_t len,
- enum tdb_lock_flags flags)
-{
- int ret;
-
- if (tdb->flags & TDB_NOLOCK) {
- return TDB_SUCCESS;
- }
-
- if (rw_type == F_WRLCK && (tdb->flags & TDB_RDONLY)) {
- return tdb_logerr(tdb, TDB_ERR_RDONLY, TDB_LOG_USE_ERROR,
- "Write lock attempted on read-only database");
- }
-
- /* A 32 bit system cannot open a 64-bit file, but it could have
- * expanded since then: check here. */
- if ((size_t)(offset + len) != offset + len) {
- return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
- "tdb_brlock: lock on giant offset %llu",
- (long long)(offset + len));
- }
-
- ret = lock(tdb, rw_type, offset, len, flags & TDB_LOCK_WAIT);
- if (ret != 0) {
- /* Generic lock error. errno set by fcntl.
- * EAGAIN is an expected return from non-blocking
- * locks. */
- if (!(flags & TDB_LOCK_PROBE)
- && (errno != EAGAIN && errno != EINTR)) {
- tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_brlock failed (fd=%d) at"
- " offset %zu rw_type=%d flags=%d len=%zu:"
- " %s",
- tdb->file->fd, (size_t)offset, rw_type,
- flags, (size_t)len, strerror(errno));
- }
- return TDB_ERR_LOCK;
- }
- return TDB_SUCCESS;
-}
-
-enum TDB_ERROR tdb_brunlock(struct tdb_context *tdb,
- int rw_type, tdb_off_t offset, size_t len)
-{
- if (tdb->flags & TDB_NOLOCK) {
- return TDB_SUCCESS;
- }
-
- if (!check_lock_pid(tdb, "tdb_brunlock", true))
- return TDB_ERR_LOCK;
-
- if (unlock(tdb, rw_type, offset, len) == -1) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_brunlock failed (fd=%d) at offset %zu"
- " rw_type=%d len=%zu: %s",
- tdb->file->fd, (size_t)offset, rw_type,
- (size_t)len, strerror(errno));
- }
- return TDB_SUCCESS;
-}
-
-/*
- upgrade a read lock to a write lock. This needs to be handled in a
- special way as some OSes (such as solaris) have too conservative
- deadlock detection and claim a deadlock when progress can be
- made. For those OSes we may loop for a while.
-*/
-enum TDB_ERROR tdb_allrecord_upgrade(struct tdb_context *tdb, off_t start)
-{
- int count = 1000;
-
- if (!check_lock_pid(tdb, "tdb_transaction_prepare_commit", true))
- return TDB_ERR_LOCK;
-
- if (tdb->file->allrecord_lock.count != 1) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_allrecord_upgrade failed:"
- " count %u too high",
- tdb->file->allrecord_lock.count);
- }
-
- if (tdb->file->allrecord_lock.off != 1) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_allrecord_upgrade failed:"
- " already upgraded?");
- }
-
- if (tdb->file->allrecord_lock.owner != tdb) {
- return owner_conflict(tdb, "tdb_allrecord_upgrade");
- }
-
- while (count--) {
- struct timeval tv;
- if (tdb_brlock(tdb, F_WRLCK, start, 0,
- TDB_LOCK_WAIT|TDB_LOCK_PROBE) == TDB_SUCCESS) {
- tdb->file->allrecord_lock.ltype = F_WRLCK;
- tdb->file->allrecord_lock.off = 0;
- return TDB_SUCCESS;
- }
- if (errno != EDEADLK) {
- break;
- }
- /* sleep for as short a time as we can - more portable than usleep() */
- tv.tv_sec = 0;
- tv.tv_usec = 1;
- select(0, NULL, NULL, NULL, &tv);
- }
-
- if (errno != EAGAIN && errno != EINTR)
- tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_allrecord_upgrade failed");
- return TDB_ERR_LOCK;
-}
-
-static struct tdb_lock *find_nestlock(struct tdb_context *tdb, tdb_off_t offset,
- const struct tdb_context *owner)
-{
- unsigned int i;
-
- for (i=0; i<tdb->file->num_lockrecs; i++) {
- if (tdb->file->lockrecs[i].off == offset) {
- if (owner && tdb->file->lockrecs[i].owner != owner)
- return NULL;
- return &tdb->file->lockrecs[i];
- }
- }
- return NULL;
-}
-
-enum TDB_ERROR tdb_lock_and_recover(struct tdb_context *tdb)
-{
- enum TDB_ERROR ecode;
-
- if (!check_lock_pid(tdb, "tdb_transaction_prepare_commit", true))
- return TDB_ERR_LOCK;
-
- ecode = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK,
- false);
- if (ecode != TDB_SUCCESS) {
- return ecode;
- }
-
- ecode = tdb_lock_open(tdb, F_WRLCK, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
- if (ecode != TDB_SUCCESS) {
- tdb_allrecord_unlock(tdb, F_WRLCK);
- return ecode;
- }
- ecode = tdb_transaction_recover(tdb);
- tdb_unlock_open(tdb, F_WRLCK);
- tdb_allrecord_unlock(tdb, F_WRLCK);
-
- return ecode;
-}
-
-/* lock an offset in the database. */
-enum TDB_ERROR tdb_nest_lock(struct tdb_context *tdb,
- tdb_off_t offset, int ltype,
- enum tdb_lock_flags flags)
-{
- struct tdb_lock *new_lck;
- enum TDB_ERROR ecode;
-
- if (!(tdb->flags & TDB_VERSION1)
- && offset > (TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE
- + tdb->file->map_size / 8)) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_nest_lock: invalid offset %zu ltype=%d",
- (size_t)offset, ltype);
- }
-
- if (tdb->flags & TDB_NOLOCK)
- return TDB_SUCCESS;
-
- if (!check_lock_pid(tdb, "tdb_nest_lock", true)) {
- return TDB_ERR_LOCK;
- }
-
- tdb->stats.locks++;
-
- new_lck = find_nestlock(tdb, offset, NULL);
- if (new_lck) {
- if (new_lck->owner != tdb) {
- return owner_conflict(tdb, "tdb_nest_lock");
- }
-
- if (new_lck->ltype == F_RDLCK && ltype == F_WRLCK) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_nest_lock:"
- " offset %zu has read lock",
- (size_t)offset);
- }
- /* Just increment the struct, posix locks don't stack. */
- new_lck->count++;
- return TDB_SUCCESS;
- }
-
-#if 0
- if (tdb->file->num_lockrecs
- && offset >= TDB_HASH_LOCK_START
- && offset < TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_nest_lock: already have a hash lock?");
- }
-#endif
-
- new_lck = (struct tdb_lock *)realloc(
- tdb->file->lockrecs,
- sizeof(*tdb->file->lockrecs) * (tdb->file->num_lockrecs+1));
- if (new_lck == NULL) {
- return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
- "tdb_nest_lock:"
- " unable to allocate %zu lock struct",
- tdb->file->num_lockrecs + 1);
- }
- tdb->file->lockrecs = new_lck;
-
- /* Since fcntl locks don't nest, we do a lock for the first one,
- and simply bump the count for future ones */
- ecode = tdb_brlock(tdb, ltype, offset, 1, flags);
- if (ecode != TDB_SUCCESS) {
- return ecode;
- }
-
- /* First time we grab a lock, perhaps someone died in commit? */
- if (!(flags & TDB_LOCK_NOCHECK)
- && tdb->file->num_lockrecs == 0) {
- tdb_bool_err berr = tdb_needs_recovery(tdb);
- if (berr != false) {
- tdb_brunlock(tdb, ltype, offset, 1);
-
- if (berr < 0)
- return TDB_OFF_TO_ERR(berr);
- ecode = tdb_lock_and_recover(tdb);
- if (ecode == TDB_SUCCESS) {
- ecode = tdb_brlock(tdb, ltype, offset, 1,
- flags);
- }
- if (ecode != TDB_SUCCESS) {
- return ecode;
- }
- }
- }
-
- tdb->file->lockrecs[tdb->file->num_lockrecs].owner = tdb;
- tdb->file->lockrecs[tdb->file->num_lockrecs].off = offset;
- tdb->file->lockrecs[tdb->file->num_lockrecs].count = 1;
- tdb->file->lockrecs[tdb->file->num_lockrecs].ltype = ltype;
- tdb->file->num_lockrecs++;
-
- return TDB_SUCCESS;
-}
-
-enum TDB_ERROR tdb_nest_unlock(struct tdb_context *tdb,
- tdb_off_t off, int ltype)
-{
- struct tdb_lock *lck;
- enum TDB_ERROR ecode;
-
- if (tdb->flags & TDB_NOLOCK)
- return TDB_SUCCESS;
-
- lck = find_nestlock(tdb, off, tdb);
- if ((lck == NULL) || (lck->count == 0)) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_nest_unlock: no lock for %zu",
- (size_t)off);
- }
-
- if (lck->count > 1) {
- lck->count--;
- return TDB_SUCCESS;
- }
-
- /*
- * This lock has count==1 left, so we need to unlock it in the
- * kernel. We don't bother with decrementing the in-memory array
- * element, we're about to overwrite it with the last array element
- * anyway.
- */
- ecode = tdb_brunlock(tdb, ltype, off, 1);
-
- /*
- * Shrink the array by overwriting the element just unlocked with the
- * last array element.
- */
- *lck = tdb->file->lockrecs[--tdb->file->num_lockrecs];
-
- return ecode;
-}
-
-/*
- get the transaction lock
- */
-enum TDB_ERROR tdb_transaction_lock(struct tdb_context *tdb, int ltype)
-{
- return tdb_nest_lock(tdb, TDB_TRANSACTION_LOCK, ltype, TDB_LOCK_WAIT);
-}
-
-/*
- release the transaction lock
- */
-void tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
-{
- tdb_nest_unlock(tdb, TDB_TRANSACTION_LOCK, ltype);
-}
-
-/* We only need to lock individual bytes, but Linux merges consecutive locks
- * so we lock in contiguous ranges. */
-enum TDB_ERROR tdb_lock_gradual(struct tdb_context *tdb,
- int ltype, enum tdb_lock_flags flags,
- tdb_off_t off, tdb_off_t len)
-{
- enum TDB_ERROR ecode;
- enum tdb_lock_flags nb_flags = (flags & ~TDB_LOCK_WAIT);
-
- if (len <= 1) {
- /* 0 would mean to end-of-file... */
- assert(len != 0);
- /* Single hash. Just do blocking lock. */
- return tdb_brlock(tdb, ltype, off, len, flags);
- }
-
- /* First we try non-blocking. */
- ecode = tdb_brlock(tdb, ltype, off, len, nb_flags);
- if (ecode != TDB_ERR_LOCK) {
- return ecode;
- }
-
- /* Try locking first half, then second. */
- ecode = tdb_lock_gradual(tdb, ltype, flags, off, len / 2);
- if (ecode != TDB_SUCCESS)
- return ecode;
-
- ecode = tdb_lock_gradual(tdb, ltype, flags,
- off + len / 2, len - len / 2);
- if (ecode != TDB_SUCCESS) {
- tdb_brunlock(tdb, ltype, off, len / 2);
- }
- return ecode;
-}
-
-/* lock/unlock entire database. It can only be upgradable if you have some
- * other way of guaranteeing exclusivity (ie. transaction write lock). */
-enum TDB_ERROR tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags flags, bool upgradable)
-{
- enum TDB_ERROR ecode;
- tdb_bool_err berr;
-
- if (tdb->flags & TDB_VERSION1) {
- if (tdb1_allrecord_lock(tdb, ltype, flags, upgradable) == -1)
- return tdb->last_error;
- return TDB_SUCCESS;
- }
-
- if (tdb->flags & TDB_NOLOCK)
- return TDB_SUCCESS;
-
- if (!check_lock_pid(tdb, "tdb_allrecord_lock", true)) {
- return TDB_ERR_LOCK;
- }
-
- if (tdb->file->allrecord_lock.count) {
- if (tdb->file->allrecord_lock.owner != tdb) {
- return owner_conflict(tdb, "tdb_allrecord_lock");
- }
-
- if (ltype == F_RDLCK
- || tdb->file->allrecord_lock.ltype == F_WRLCK) {
- tdb->file->allrecord_lock.count++;
- return TDB_SUCCESS;
- }
-
- /* a global lock of a different type exists */
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_allrecord_lock: already have %s lock",
- tdb->file->allrecord_lock.ltype == F_RDLCK
- ? "read" : "write");
- }
-
- if (tdb_has_hash_locks(tdb)) {
- /* can't combine global and chain locks */
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_allrecord_lock:"
- " already have chain lock");
- }
-
- if (upgradable && ltype != F_RDLCK) {
- /* tdb error: you can't upgrade a write lock! */
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_allrecord_lock:"
- " can't upgrade a write lock");
- }
-
- tdb->stats.locks++;
-again:
- /* Lock hashes, gradually. */
- ecode = tdb_lock_gradual(tdb, ltype, flags, TDB_HASH_LOCK_START,
- TDB_HASH_LOCK_RANGE);
- if (ecode != TDB_SUCCESS)
- return ecode;
-
- /* Lock free tables: there to end of file. */
- ecode = tdb_brlock(tdb, ltype,
- TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE,
- 0, flags);
- if (ecode != TDB_SUCCESS) {
- tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START,
- TDB_HASH_LOCK_RANGE);
- return ecode;
- }
-
- tdb->file->allrecord_lock.owner = tdb;
- tdb->file->allrecord_lock.count = 1;
- /* If it's upgradable, it's actually exclusive so we can treat
- * it as a write lock. */
- tdb->file->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
- tdb->file->allrecord_lock.off = upgradable;
-
- /* Now check for needing recovery. */
- if (flags & TDB_LOCK_NOCHECK)
- return TDB_SUCCESS;
-
- berr = tdb_needs_recovery(tdb);
- if (likely(berr == false))
- return TDB_SUCCESS;
-
- tdb_allrecord_unlock(tdb, ltype);
- if (berr < 0)
- return TDB_OFF_TO_ERR(berr);
- ecode = tdb_lock_and_recover(tdb);
- if (ecode != TDB_SUCCESS) {
- return ecode;
- }
- goto again;
-}
-
-enum TDB_ERROR tdb_lock_open(struct tdb_context *tdb,
- int ltype, enum tdb_lock_flags flags)
-{
- return tdb_nest_lock(tdb, TDB_OPEN_LOCK, ltype, flags);
-}
-
-void tdb_unlock_open(struct tdb_context *tdb, int ltype)
-{
- tdb_nest_unlock(tdb, TDB_OPEN_LOCK, ltype);
-}
-
-bool tdb_has_open_lock(struct tdb_context *tdb)
-{
- return !(tdb->flags & TDB_NOLOCK)
- && find_nestlock(tdb, TDB_OPEN_LOCK, tdb) != NULL;
-}
-
-enum TDB_ERROR tdb_lock_expand(struct tdb_context *tdb, int ltype)
-{
- /* Lock doesn't protect data, so don't check (we recurse if we do!) */
- return tdb_nest_lock(tdb, TDB_EXPANSION_LOCK, ltype,
- TDB_LOCK_WAIT | TDB_LOCK_NOCHECK);
-}
-
-void tdb_unlock_expand(struct tdb_context *tdb, int ltype)
-{
- tdb_nest_unlock(tdb, TDB_EXPANSION_LOCK, ltype);
-}
-
-/* unlock entire db */
-void tdb_allrecord_unlock(struct tdb_context *tdb, int ltype)
-{
- if (tdb->flags & TDB_VERSION1) {
- tdb1_allrecord_unlock(tdb, ltype);
- return;
- }
-
- if (tdb->flags & TDB_NOLOCK)
- return;
-
- if (tdb->file->allrecord_lock.count == 0) {
- tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_allrecord_unlock: not locked!");
- return;
- }
-
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_allrecord_unlock: not locked by us!");
- return;
- }
-
- /* Upgradable locks are marked as write locks. */
- if (tdb->file->allrecord_lock.ltype != ltype
- && (!tdb->file->allrecord_lock.off || ltype != F_RDLCK)) {
- tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_allrecord_unlock: have %s lock",
- tdb->file->allrecord_lock.ltype == F_RDLCK
- ? "read" : "write");
- return;
- }
-
- if (tdb->file->allrecord_lock.count > 1) {
- tdb->file->allrecord_lock.count--;
- return;
- }
-
- tdb->file->allrecord_lock.count = 0;
- tdb->file->allrecord_lock.ltype = 0;
-
- tdb_brunlock(tdb, ltype, TDB_HASH_LOCK_START, 0);
-}
-
-bool tdb_has_expansion_lock(struct tdb_context *tdb)
-{
- return find_nestlock(tdb, TDB_EXPANSION_LOCK, tdb) != NULL;
-}
-
-bool tdb_has_hash_locks(struct tdb_context *tdb)
-{
- unsigned int i;
-
- for (i=0; i<tdb->file->num_lockrecs; i++) {
- if (tdb->file->lockrecs[i].off >= TDB_HASH_LOCK_START
- && tdb->file->lockrecs[i].off < (TDB_HASH_LOCK_START
- + TDB_HASH_LOCK_RANGE))
- return true;
- }
- return false;
-}
-
-static bool tdb_has_free_lock(struct tdb_context *tdb)
-{
- unsigned int i;
-
- if (tdb->flags & TDB_NOLOCK)
- return false;
-
- for (i=0; i<tdb->file->num_lockrecs; i++) {
- if (tdb->file->lockrecs[i].off
- > TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE)
- return true;
- }
- return false;
-}
-
-enum TDB_ERROR tdb_lock_hashes(struct tdb_context *tdb,
- tdb_off_t hash_lock,
- tdb_len_t hash_range,
- int ltype, enum tdb_lock_flags waitflag)
-{
- /* FIXME: Do this properly, using hlock_range */
- unsigned l = TDB_HASH_LOCK_START
- + (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
-
- /* a allrecord lock allows us to avoid per chain locks */
- if (tdb->file->allrecord_lock.count) {
- if (!check_lock_pid(tdb, "tdb_lock_hashes", true))
- return TDB_ERR_LOCK;
-
- if (tdb->file->allrecord_lock.owner != tdb)
- return owner_conflict(tdb, "tdb_lock_hashes");
- if (ltype == tdb->file->allrecord_lock.ltype
- || ltype == F_RDLCK) {
- return TDB_SUCCESS;
- }
-
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_lock_hashes:"
- " already have %s allrecordlock",
- tdb->file->allrecord_lock.ltype == F_RDLCK
- ? "read" : "write");
- }
-
- if (tdb_has_free_lock(tdb)) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_lock_hashes: already have free lock");
- }
-
- if (tdb_has_expansion_lock(tdb)) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_lock_hashes:"
- " already have expansion lock");
- }
-
- return tdb_nest_lock(tdb, l, ltype, waitflag);
-}
-
-enum TDB_ERROR tdb_unlock_hashes(struct tdb_context *tdb,
- tdb_off_t hash_lock,
- tdb_len_t hash_range, int ltype)
-{
- unsigned l = TDB_HASH_LOCK_START
- + (hash_lock >> (64 - TDB_HASH_LOCK_RANGE_BITS));
-
- if (tdb->flags & TDB_NOLOCK)
- return 0;
-
- /* a allrecord lock allows us to avoid per chain locks */
- if (tdb->file->allrecord_lock.count) {
- if (tdb->file->allrecord_lock.ltype == F_RDLCK
- && ltype == F_WRLCK) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_unlock_hashes RO allrecord!");
- }
- if (tdb->file->allrecord_lock.owner != tdb) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
- "tdb_unlock_hashes:"
- " not locked by us!");
- }
- return TDB_SUCCESS;
- }
-
- return tdb_nest_unlock(tdb, l, ltype);
-}
-
-/* Hash locks use TDB_HASH_LOCK_START + the next 30 bits.
- * Then we begin; bucket offsets are sizeof(tdb_len_t) apart, so we divide.
- * The result is that on 32 bit systems we don't use lock values > 2^31 on
- * files that are less than 4GB.
- */
-static tdb_off_t free_lock_off(tdb_off_t b_off)
-{
- return TDB_HASH_LOCK_START + TDB_HASH_LOCK_RANGE
- + b_off / sizeof(tdb_off_t);
-}
-
-enum TDB_ERROR tdb_lock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off,
- enum tdb_lock_flags waitflag)
-{
- assert(b_off >= sizeof(struct tdb_header));
-
- if (tdb->flags & TDB_NOLOCK)
- return 0;
-
- /* a allrecord lock allows us to avoid per chain locks */
- if (tdb->file->allrecord_lock.count) {
- if (!check_lock_pid(tdb, "tdb_lock_free_bucket", true))
- return TDB_ERR_LOCK;
-
- if (tdb->file->allrecord_lock.owner != tdb) {
- return owner_conflict(tdb, "tdb_lock_free_bucket");
- }
-
- if (tdb->file->allrecord_lock.ltype == F_WRLCK)
- return 0;
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_lock_free_bucket with"
- " read-only allrecordlock!");
- }
-
-#if 0 /* FIXME */
- if (tdb_has_expansion_lock(tdb)) {
- return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb_lock_free_bucket:"
- " already have expansion lock");
- }
-#endif
-
- return tdb_nest_lock(tdb, free_lock_off(b_off), F_WRLCK, waitflag);
-}
-
-void tdb_unlock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off)
-{
- if (tdb->file->allrecord_lock.count)
- return;
-
- tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
-}
-
-enum TDB_ERROR tdb_lockall(struct tdb_context *tdb)
-{
- return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
-}
-
-void tdb_unlockall(struct tdb_context *tdb)
-{
- tdb_allrecord_unlock(tdb, F_WRLCK);
-}
-
-enum TDB_ERROR tdb_lockall_read(struct tdb_context *tdb)
-{
- return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
-}
-
-void tdb_unlockall_read(struct tdb_context *tdb)
-{
- tdb_allrecord_unlock(tdb, F_RDLCK);
-}
-
-void tdb_lock_cleanup(struct tdb_context *tdb)
-{
- unsigned int i;
-
- /* We don't want to warn: they're allowed to close tdb after fork. */
- if (!check_lock_pid(tdb, "tdb_close", false))
- return;
-
- while (tdb->file->allrecord_lock.count
- && tdb->file->allrecord_lock.owner == tdb) {
- tdb_allrecord_unlock(tdb, tdb->file->allrecord_lock.ltype);
- }
-
- for (i=0; i<tdb->file->num_lockrecs; i++) {
- if (tdb->file->lockrecs[i].owner == tdb) {
- tdb_nest_unlock(tdb,
- tdb->file->lockrecs[i].off,
- tdb->file->lockrecs[i].ltype);
- i--;
- }
- }
-}
projects / ccan / blobdiff