+++ /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 "tdb_private.h"
-
-void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr)
-{
- tdb->interrupt_sig_ptr = ptr;
-}
-
-static int fcntl_lock(struct tdb_context *tdb,
- int rw, off_t off, off_t len, bool waitflag)
-{
- struct flock fl;
-
- fl.l_type = rw;
- fl.l_whence = SEEK_SET;
- fl.l_start = off;
- fl.l_len = len;
- fl.l_pid = 0;
-
- if (waitflag)
- return fcntl(tdb->fd, F_SETLKW, &fl);
- else
- return fcntl(tdb->fd, F_SETLK, &fl);
-}
-
-static int fcntl_unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
-{
- struct flock fl;
-#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!\n",
- (int)off, (int)len);
- abort();
- }
-
- fclose(locks);
-#endif
-
- fl.l_type = F_UNLCK;
- fl.l_whence = SEEK_SET;
- fl.l_start = off;
- fl.l_len = len;
- fl.l_pid = 0;
-
- return fcntl(tdb->fd, F_SETLKW, &fl);
-}
-
-/* list -1 is the alloc list, otherwise a hash chain. */
-static tdb_off_t lock_offset(int list)
-{
- return FREELIST_TOP + 4*list;
-}
-
-/* a byte range locking function - return 0 on success
- this functions locks/unlocks 1 byte at the specified offset.
-
- On error, errno is also set so that errors are passed back properly
- through tdb_open().
-
- note that a len of zero means lock to end of file
-*/
-int tdb_brlock(struct tdb_context *tdb,
- int rw_type, tdb_off_t offset, size_t len,
- enum tdb_lock_flags flags)
-{
- int ret;
-
- if (tdb->flags & TDB_NOLOCK) {
- return 0;
- }
-
- if (flags & TDB_LOCK_MARK_ONLY) {
- return 0;
- }
-
- if ((rw_type == F_WRLCK) && (tdb->read_only || tdb->traverse_read)) {
- tdb->ecode = TDB_ERR_RDONLY;
- return -1;
- }
-
- do {
- ret = fcntl_lock(tdb, rw_type, offset, len,
- flags & TDB_LOCK_WAIT);
- /* Check for a sigalarm break. */
- if (ret == -1 && errno == EINTR &&
- tdb->interrupt_sig_ptr &&
- *tdb->interrupt_sig_ptr) {
- break;
- }
- } while (ret == -1 && errno == EINTR);
-
- if (ret == -1) {
- tdb->ecode = TDB_ERR_LOCK;
- /* Generic lock error. errno set by fcntl.
- * EAGAIN is an expected return from non-blocking
- * locks. */
- if (!(flags & TDB_LOCK_PROBE) && errno != EAGAIN) {
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d flags=%d len=%d\n",
- tdb->fd, offset, rw_type, flags, (int)len));
- }
- return -1;
- }
- return 0;
-}
-
-int tdb_brunlock(struct tdb_context *tdb,
- int rw_type, tdb_off_t offset, size_t len)
-{
- int ret;
-
- if (tdb->flags & TDB_NOLOCK) {
- return 0;
- }
-
- do {
- ret = fcntl_unlock(tdb, rw_type, offset, len);
- } while (ret == -1 && errno == EINTR);
-
- if (ret == -1) {
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brunlock failed (fd=%d) at offset %d rw_type=%d len=%d\n",
- tdb->fd, offset, rw_type, (int)len));
- }
- return ret;
-}
-
-/*
- 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.
-*/
-int tdb_allrecord_upgrade(struct tdb_context *tdb)
-{
- int count = 1000;
-
- if (tdb->allrecord_lock.count != 1) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR,
- "tdb_allrecord_upgrade failed: count %u too high\n",
- tdb->allrecord_lock.count));
- return -1;
- }
-
- if (tdb->allrecord_lock.off != 1) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR,
- "tdb_allrecord_upgrade failed: already upgraded?\n"));
- return -1;
- }
-
- while (count--) {
- struct timeval tv;
- if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0,
- TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {
- tdb->allrecord_lock.ltype = F_WRLCK;
- tdb->allrecord_lock.off = 0;
- return 0;
- }
- 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);
- }
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_allrecord_upgrade failed\n"));
- return -1;
-}
-
-static struct tdb_lock_type *find_nestlock(struct tdb_context *tdb,
- tdb_off_t offset)
-{
- unsigned int i;
-
- for (i=0; i<tdb->num_lockrecs; i++) {
- if (tdb->lockrecs[i].off == offset) {
- return &tdb->lockrecs[i];
- }
- }
- return NULL;
-}
-
-/* lock an offset in the database. */
-int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
- enum tdb_lock_flags flags)
-{
- struct tdb_lock_type *new_lck;
-
- if (offset >= lock_offset(tdb->header.hash_size)) {
- tdb->ecode = TDB_ERR_LOCK;
- TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_lock: invalid offset %u for ltype=%d\n",
- offset, ltype));
- return -1;
- }
- if (tdb->flags & TDB_NOLOCK)
- return 0;
-
- new_lck = find_nestlock(tdb, offset);
- if (new_lck) {
- /*
- * Just increment the in-memory struct, posix locks
- * don't stack.
- */
- new_lck->count++;
- return 0;
- }
-
- new_lck = (struct tdb_lock_type *)realloc(
- tdb->lockrecs,
- sizeof(*tdb->lockrecs) * (tdb->num_lockrecs+1));
- if (new_lck == NULL) {
- errno = ENOMEM;
- return -1;
- }
- tdb->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 */
- if (tdb_brlock(tdb, ltype, offset, 1, flags)) {
- return -1;
- }
-
- tdb->lockrecs[tdb->num_lockrecs].off = offset;
- tdb->lockrecs[tdb->num_lockrecs].count = 1;
- tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
- tdb->num_lockrecs++;
-
- return 0;
-}
-
-static int tdb_lock_and_recover(struct tdb_context *tdb)
-{
- int ret;
-
- /* We need to match locking order in transaction commit. */
- if (tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0, TDB_LOCK_WAIT)) {
- return -1;
- }
-
- if (tdb_brlock(tdb, F_WRLCK, OPEN_LOCK, 1, TDB_LOCK_WAIT)) {
- tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
- return -1;
- }
-
- ret = tdb_transaction_recover(tdb);
-
- tdb_brunlock(tdb, F_WRLCK, OPEN_LOCK, 1);
- tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);
-
- return ret;
-}
-
-static bool have_data_locks(const struct tdb_context *tdb)
-{
- unsigned int i;
-
- for (i = 0; i < tdb->num_lockrecs; i++) {
- if (tdb->lockrecs[i].off >= lock_offset(-1))
- return true;
- }
- return false;
-}
-
-static int tdb_lock_list(struct tdb_context *tdb, int list, int ltype,
- enum tdb_lock_flags waitflag)
-{
- int ret;
- bool check = false;
-
- /* a allrecord lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count &&
- (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
- return 0;
- }
-
- if (tdb->allrecord_lock.count) {
- tdb->ecode = TDB_ERR_LOCK;
- ret = -1;
- } else {
- /* Only check when we grab first data lock. */
- check = !have_data_locks(tdb);
- ret = tdb_nest_lock(tdb, lock_offset(list), ltype, waitflag);
-
- if (ret == 0 && check && tdb_needs_recovery(tdb)) {
- tdb_nest_unlock(tdb, lock_offset(list), ltype, false);
-
- if (tdb_lock_and_recover(tdb) == -1) {
- return -1;
- }
- return tdb_lock_list(tdb, list, ltype, waitflag);
- }
- }
- return ret;
-}
-
-/* lock a list in the database. list -1 is the alloc list */
-int tdb_lock(struct tdb_context *tdb, int list, int ltype)
-{
- int ret;
-
- ret = tdb_lock_list(tdb, list, ltype, TDB_LOCK_WAIT);
- if (ret) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d "
- "ltype=%d (%s)\n", list, ltype, strerror(errno)));
- }
- return ret;
-}
-
-/* lock a list in the database. list -1 is the alloc list. non-blocking lock */
-int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype)
-{
- return tdb_lock_list(tdb, list, ltype, TDB_LOCK_NOWAIT);
-}
-
-
-int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
- bool mark_lock)
-{
- int ret = -1;
- struct tdb_lock_type *lck;
-
- if (tdb->flags & TDB_NOLOCK)
- return 0;
-
- /* Sanity checks */
- if (offset >= lock_offset(tdb->header.hash_size)) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: offset %u invalid (%d)\n", offset, tdb->header.hash_size));
- return ret;
- }
-
- lck = find_nestlock(tdb, offset);
- if ((lck == NULL) || (lck->count == 0)) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: count is 0\n"));
- return -1;
- }
-
- if (lck->count > 1) {
- lck->count--;
- return 0;
- }
-
- /*
- * 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.
- */
-
- if (mark_lock) {
- ret = 0;
- } else {
- ret = tdb_brunlock(tdb, ltype, offset, 1);
- }
-
- /*
- * Shrink the array by overwriting the element just unlocked with the
- * last array element.
- */
- *lck = tdb->lockrecs[--tdb->num_lockrecs];
-
- /*
- * We don't bother with realloc when the array shrinks, but if we have
- * a completely idle tdb we should get rid of the locked array.
- */
-
- if (tdb->num_lockrecs == 0) {
- SAFE_FREE(tdb->lockrecs);
- }
-
- if (ret)
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: An error occurred unlocking!\n"));
- return ret;
-}
-
-int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
-{
- /* a global lock allows us to avoid per chain locks */
- if (tdb->allrecord_lock.count &&
- (ltype == tdb->allrecord_lock.ltype || ltype == F_RDLCK)) {
- return 0;
- }
-
- if (tdb->allrecord_lock.count) {
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- return tdb_nest_unlock(tdb, lock_offset(list), ltype, false);
-}
-
-/*
- get the transaction lock
- */
-int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
-{
- return tdb_nest_lock(tdb, TRANSACTION_LOCK, ltype, TDB_LOCK_WAIT);
-}
-
-/*
- release the transaction lock
- */
-int tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
-{
- return tdb_nest_unlock(tdb, TRANSACTION_LOCK, ltype, false);
-}
-
-/* Returns 0 if all done, -1 if error, 1 if ok. */
-static int tdb_allrecord_check(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags flags, bool upgradable)
-{
- /* There are no locks on read-only dbs */
- if (tdb->read_only || tdb->traverse_read) {
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- if (tdb->allrecord_lock.count && tdb->allrecord_lock.ltype == ltype) {
- tdb->allrecord_lock.count++;
- return 0;
- }
-
- if (tdb->allrecord_lock.count) {
- /* a global lock of a different type exists */
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- if (tdb_have_extra_locks(tdb)) {
- /* can't combine global and chain locks */
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- if (upgradable && ltype != F_RDLCK) {
- /* tdb error: you can't upgrade a write lock! */
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
- return 1;
-}
-
-/* We only need to lock individual bytes, but Linux merges consecutive locks
- * so we lock in contiguous ranges. */
-static int tdb_chainlock_gradual(struct tdb_context *tdb,
- int ltype, enum tdb_lock_flags flags,
- size_t off, size_t len)
-{
- int ret;
- enum tdb_lock_flags nb_flags = (flags & ~TDB_LOCK_WAIT);
-
- if (len <= 4) {
- /* Single record. Just do blocking lock. */
- return tdb_brlock(tdb, ltype, off, len, flags);
- }
-
- /* First we try non-blocking. */
- ret = tdb_brlock(tdb, ltype, off, len, nb_flags);
- if (ret == 0) {
- return 0;
- }
-
- /* Try locking first half, then second. */
- ret = tdb_chainlock_gradual(tdb, ltype, flags, off, len / 2);
- if (ret == -1)
- return -1;
-
- ret = tdb_chainlock_gradual(tdb, ltype, flags,
- off + len / 2, len - len / 2);
- if (ret == -1) {
- tdb_brunlock(tdb, ltype, off, len / 2);
- return -1;
- }
- return 0;
-}
-
-/* lock/unlock entire database. It can only be upgradable if you have some
- * other way of guaranteeing exclusivity (ie. transaction write lock).
- * We do the locking gradually to avoid being starved by smaller locks. */
-int tdb_allrecord_lock(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags flags, bool upgradable)
-{
- switch (tdb_allrecord_check(tdb, ltype, flags, upgradable)) {
- case -1:
- return -1;
- case 0:
- return 0;
- }
-
- /* We cover two kinds of locks:
- * 1) Normal chain locks. Taken for almost all operations.
- * 3) Individual records locks. Taken after normal or free
- * chain locks.
- *
- * It is (1) which cause the starvation problem, so we're only
- * gradual for that. */
- if (tdb_chainlock_gradual(tdb, ltype, flags, FREELIST_TOP,
- tdb->header.hash_size * 4) == -1) {
- return -1;
- }
-
- /* Grab individual record locks. */
- if (tdb_brlock(tdb, ltype, lock_offset(tdb->header.hash_size), 0,
- flags) == -1) {
- tdb_brunlock(tdb, ltype, FREELIST_TOP,
- tdb->header.hash_size * 4);
- return -1;
- }
-
- tdb->allrecord_lock.count = 1;
- /* If it's upgradable, it's actually exclusive so we can treat
- * it as a write lock. */
- tdb->allrecord_lock.ltype = upgradable ? F_WRLCK : ltype;
- tdb->allrecord_lock.off = upgradable;
-
- if (tdb_needs_recovery(tdb)) {
- bool mark = flags & TDB_LOCK_MARK_ONLY;
- tdb_allrecord_unlock(tdb, ltype, mark);
- if (mark) {
- tdb->ecode = TDB_ERR_LOCK;
- TDB_LOG((tdb, TDB_DEBUG_ERROR,
- "tdb_lockall_mark cannot do recovery\n"));
- return -1;
- }
- if (tdb_lock_and_recover(tdb) == -1) {
- return -1;
- }
- return tdb_allrecord_lock(tdb, ltype, flags, upgradable);
- }
-
- return 0;
-}
-
-
-
-/* unlock entire db */
-int tdb_allrecord_unlock(struct tdb_context *tdb, int ltype, bool mark_lock)
-{
- /* There are no locks on read-only dbs */
- if (tdb->read_only || tdb->traverse_read) {
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- if (tdb->allrecord_lock.count == 0) {
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- /* Upgradable locks are marked as write locks. */
- if (tdb->allrecord_lock.ltype != ltype
- && (!tdb->allrecord_lock.off || ltype != F_RDLCK)) {
- tdb->ecode = TDB_ERR_LOCK;
- return -1;
- }
-
- if (tdb->allrecord_lock.count > 1) {
- tdb->allrecord_lock.count--;
- return 0;
- }
-
- if (!mark_lock && tdb_brunlock(tdb, ltype, FREELIST_TOP, 0)) {
- TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed (%s)\n", strerror(errno)));
- return -1;
- }
-
- tdb->allrecord_lock.count = 0;
- tdb->allrecord_lock.ltype = 0;
-
- return 0;
-}
-
-/* lock entire database with write lock */
-int tdb_lockall(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_lockall");
- return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
-}
-
-/* lock entire database with write lock - mark only */
-int tdb_lockall_mark(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_lockall_mark");
- return tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY, false);
-}
-
-/* unlock entire database with write lock - unmark only */
-int tdb_lockall_unmark(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_lockall_unmark");
- return tdb_allrecord_unlock(tdb, F_WRLCK, true);
-}
-
-/* lock entire database with write lock - nonblocking varient */
-int tdb_lockall_nonblock(struct tdb_context *tdb)
-{
- int ret = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_NOWAIT, false);
- tdb_trace_ret(tdb, "tdb_lockall_nonblock", ret);
- return ret;
-}
-
-/* unlock entire database with write lock */
-int tdb_unlockall(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_unlockall");
- return tdb_allrecord_unlock(tdb, F_WRLCK, false);
-}
-
-/* lock entire database with read lock */
-int tdb_lockall_read(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_lockall_read");
- return tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_WAIT, false);
-}
-
-/* lock entire database with read lock - nonblock varient */
-int tdb_lockall_read_nonblock(struct tdb_context *tdb)
-{
- int ret = tdb_allrecord_lock(tdb, F_RDLCK, TDB_LOCK_NOWAIT, false);
- tdb_trace_ret(tdb, "tdb_lockall_read_nonblock", ret);
- return ret;
-}
-
-/* unlock entire database with read lock */
-int tdb_unlockall_read(struct tdb_context *tdb)
-{
- tdb_trace(tdb, "tdb_unlockall_read");
- return tdb_allrecord_unlock(tdb, F_RDLCK, false);
-}
-
-/* lock/unlock one hash chain. This is meant to be used to reduce
- contention - it cannot guarantee how many records will be locked */
-int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key)
-{
- int ret = tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
- tdb_trace_1rec(tdb, "tdb_chainlock", key);
- return ret;
-}
-
-/* lock/unlock one hash chain, non-blocking. This is meant to be used
- to reduce contention - it cannot guarantee how many records will be
- locked */
-int tdb_chainlock_nonblock(struct tdb_context *tdb, TDB_DATA key)
-{
- int ret = tdb_lock_nonblock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
- tdb_trace_1rec_ret(tdb, "tdb_chainlock_nonblock", key, ret);
- return ret;
-}
-
-/* mark a chain as locked without actually locking it. Warning! use with great caution! */
-int tdb_chainlock_mark(struct tdb_context *tdb, TDB_DATA key)
-{
- int ret = tdb_nest_lock(tdb, lock_offset(BUCKET(tdb->hash_fn(&key))),
- F_WRLCK, TDB_LOCK_MARK_ONLY);
- tdb_trace_1rec(tdb, "tdb_chainlock_mark", key);
- return ret;
-}
-
-/* unmark a chain as locked without actually locking it. Warning! use with great caution! */
-int tdb_chainlock_unmark(struct tdb_context *tdb, TDB_DATA key)
-{
- tdb_trace_1rec(tdb, "tdb_chainlock_unmark", key);
- return tdb_nest_unlock(tdb, lock_offset(BUCKET(tdb->hash_fn(&key))),
- F_WRLCK, true);
-}
-
-int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
-{
- tdb_trace_1rec(tdb, "tdb_chainunlock", key);
- return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
-}
-
-int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
-{
- int ret;
- ret = tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
- tdb_trace_1rec(tdb, "tdb_chainlock_read", key);
- return ret;
-}
-
-int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
-{
- tdb_trace_1rec(tdb, "tdb_chainunlock_read", key);
- return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
-}
-
-
-
-/* record lock stops delete underneath */
-int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- if (tdb->allrecord_lock.count) {
- return 0;
- }
- return off ? tdb_brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
-}
-
-/*
- Write locks override our own fcntl readlocks, so check it here.
- Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not
- an error to fail to get the lock here.
-*/
-int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- struct tdb_traverse_lock *i;
- for (i = &tdb->travlocks; i; i = i->next)
- if (i->off == off)
- return -1;
- if (tdb->allrecord_lock.count) {
- if (tdb->allrecord_lock.ltype == F_WRLCK) {
- return 0;
- }
- return -1;
- }
- return tdb_brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
-}
-
-int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- if (tdb->allrecord_lock.count) {
- return 0;
- }
- return tdb_brunlock(tdb, F_WRLCK, off, 1);
-}
-
-/* fcntl locks don't stack: avoid unlocking someone else's */
-int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off)
-{
- struct tdb_traverse_lock *i;
- uint32_t count = 0;
-
- if (tdb->allrecord_lock.count) {
- return 0;
- }
-
- if (off == 0)
- return 0;
- for (i = &tdb->travlocks; i; i = i->next)
- if (i->off == off)
- count++;
- return (count == 1 ? tdb_brunlock(tdb, F_RDLCK, off, 1) : 0);
-}
-
-bool tdb_have_extra_locks(struct tdb_context *tdb)
-{
- unsigned int extra = tdb->num_lockrecs;
-
- /* A transaction holds the lock for all records. */
- if (!tdb->transaction && tdb->allrecord_lock.count) {
- return true;
- }
-
- /* We always hold the active lock if CLEAR_IF_FIRST. */
- if (find_nestlock(tdb, ACTIVE_LOCK)) {
- extra--;
- }
-
- /* In a transaction, we expect to hold the transaction lock */
- if (tdb->transaction && find_nestlock(tdb, TRANSACTION_LOCK)) {
- extra--;
- }
-
- return extra;
-}
-
-/* The transaction code uses this to remove all locks. Note that this
- may include OPEN_LOCK. */
-void tdb_release_extra_locks(struct tdb_context *tdb)
-{
- unsigned int i, extra = 0;
-
- if (tdb->allrecord_lock.count != 0) {
- tdb_brunlock(tdb, tdb->allrecord_lock.ltype, FREELIST_TOP, 0);
- tdb->allrecord_lock.count = 0;
- }
-
- for (i=0;i<tdb->num_lockrecs;i++) {
- struct tdb_lock_type *lck = &tdb->lockrecs[i];
-
- /* Don't release transaction or active locks! */
- if (tdb->transaction && lck->off == TRANSACTION_LOCK) {
- tdb->lockrecs[extra++] = *lck;
- } else if (lck->off == ACTIVE_LOCK) {
- tdb->lockrecs[extra++] = *lck;
- } else {
- tdb_brunlock(tdb, lck->ltype, lck->off, 1);
- }
- }
- tdb->num_lockrecs = extra;
- if (tdb->num_lockrecs == 0) {
- SAFE_FREE(tdb->lockrecs);
- }
-}
projects / ccan / blobdiff