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Diffstat (limited to 'source4/lib/tdb/common/lock.c')
| -rw-r--r-- | source4/lib/tdb/common/lock.c | 553 |
1 files changed, 0 insertions, 553 deletions
diff --git a/source4/lib/tdb/common/lock.c b/source4/lib/tdb/common/lock.c deleted file mode 100644 index f156c0fa7b..0000000000 --- a/source4/lib/tdb/common/lock.c +++ /dev/null @@ -1,553 +0,0 @@ - /* - 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" - -#define TDB_MARK_LOCK 0x80000000 - -void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr) -{ - tdb->interrupt_sig_ptr = ptr; -} - -/* 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, tdb_off_t offset, - int rw_type, int lck_type, int probe, size_t len) -{ - struct flock fl; - int ret; - - if (tdb->flags & TDB_NOLOCK) { - return 0; - } - - if ((rw_type == F_WRLCK) && (tdb->read_only || tdb->traverse_read)) { - tdb->ecode = TDB_ERR_RDONLY; - return -1; - } - - fl.l_type = rw_type; - fl.l_whence = SEEK_SET; - fl.l_start = offset; - fl.l_len = len; - fl.l_pid = 0; - - do { - ret = fcntl(tdb->fd,lck_type,&fl); - - /* 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) { - /* Generic lock error. errno set by fcntl. - * EAGAIN is an expected return from non-blocking - * locks. */ - if (!probe && lck_type != F_SETLK) { - /* Ensure error code is set for log fun to examine. */ - tdb->ecode = TDB_ERR_LOCK; - TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d lck_type=%d len=%d\n", - tdb->fd, offset, rw_type, lck_type, (int)len)); - } - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - } - return 0; -} - - -/* - 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_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len) -{ - int count = 1000; - while (count--) { - struct timeval tv; - if (tdb_brlock(tdb, offset, F_WRLCK, F_SETLKW, 1, len) == 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_brlock_upgrade failed at offset %d\n", offset)); - return -1; -} - - -/* lock a list in the database. list -1 is the alloc list */ -static int _tdb_lock(struct tdb_context *tdb, int list, int ltype, int op) -{ - struct tdb_lock_type *new_lck; - int i; - bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); - - ltype &= ~TDB_MARK_LOCK; - - /* a global lock allows us to avoid per chain locks */ - if (tdb->global_lock.count && - (ltype == tdb->global_lock.ltype || ltype == F_RDLCK)) { - return 0; - } - - if (tdb->global_lock.count) { - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - } - - if (list < -1 || list >= (int)tdb->header.hash_size) { - TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_lock: invalid list %d for ltype=%d\n", - list, ltype)); - return -1; - } - if (tdb->flags & TDB_NOLOCK) - return 0; - - for (i=0; i<tdb->num_lockrecs; i++) { - if (tdb->lockrecs[i].list == list) { - if (tdb->lockrecs[i].count == 0) { - /* - * Can't happen, see tdb_unlock(). It should - * be an assert. - */ - TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock: " - "lck->count == 0 for list %d", list)); - } - /* - * Just increment the in-memory struct, posix locks - * don't stack. - */ - tdb->lockrecs[i].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 (!mark_lock && - tdb->methods->tdb_brlock(tdb,FREELIST_TOP+4*list, ltype, op, - 0, 1)) { - return -1; - } - - tdb->num_locks++; - - tdb->lockrecs[tdb->num_lockrecs].list = list; - tdb->lockrecs[tdb->num_lockrecs].count = 1; - tdb->lockrecs[tdb->num_lockrecs].ltype = ltype; - tdb->num_lockrecs += 1; - - return 0; -} - -/* 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(tdb, list, ltype, F_SETLKW); - 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(tdb, list, ltype, F_SETLK); -} - - -/* unlock the database: returns void because it's too late for errors. */ - /* changed to return int it may be interesting to know there - has been an error --simo */ -int tdb_unlock(struct tdb_context *tdb, int list, int ltype) -{ - int ret = -1; - int i; - struct tdb_lock_type *lck = NULL; - bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); - - ltype &= ~TDB_MARK_LOCK; - - /* a global lock allows us to avoid per chain locks */ - if (tdb->global_lock.count && - (ltype == tdb->global_lock.ltype || ltype == F_RDLCK)) { - return 0; - } - - if (tdb->global_lock.count) { - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - } - - if (tdb->flags & TDB_NOLOCK) - return 0; - - /* Sanity checks */ - if (list < -1 || list >= (int)tdb->header.hash_size) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: list %d invalid (%d)\n", list, tdb->header.hash_size)); - return ret; - } - - for (i=0; i<tdb->num_lockrecs; i++) { - if (tdb->lockrecs[i].list == list) { - lck = &tdb->lockrecs[i]; - break; - } - } - - 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->methods->tdb_brlock(tdb, FREELIST_TOP+4*list, F_UNLCK, - F_SETLKW, 0, 1); - } - tdb->num_locks--; - - /* - * Shrink the array by overwriting the element just unlocked with the - * last array element. - */ - - if (tdb->num_lockrecs > 1) { - *lck = tdb->lockrecs[tdb->num_lockrecs-1]; - } - tdb->num_lockrecs -= 1; - - /* - * 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; -} - -/* - get the transaction lock - */ -int tdb_transaction_lock(struct tdb_context *tdb, int ltype) -{ - if (tdb->have_transaction_lock || tdb->global_lock.count) { - return 0; - } - if (tdb->methods->tdb_brlock(tdb, TRANSACTION_LOCK, ltype, - F_SETLKW, 0, 1) == -1) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_lock: failed to get transaction lock\n")); - tdb->ecode = TDB_ERR_LOCK; - return -1; - } - tdb->have_transaction_lock = 1; - return 0; -} - -/* - release the transaction lock - */ -int tdb_transaction_unlock(struct tdb_context *tdb) -{ - int ret; - if (!tdb->have_transaction_lock) { - return 0; - } - ret = tdb->methods->tdb_brlock(tdb, TRANSACTION_LOCK, F_UNLCK, F_SETLKW, 0, 1); - if (ret == 0) { - tdb->have_transaction_lock = 0; - } - return ret; -} - - - - -/* lock/unlock entire database */ -static int _tdb_lockall(struct tdb_context *tdb, int ltype, int op) -{ - bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); - - ltype &= ~TDB_MARK_LOCK; - - /* There are no locks on read-only dbs */ - if (tdb->read_only || tdb->traverse_read) - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - - if (tdb->global_lock.count && tdb->global_lock.ltype == ltype) { - tdb->global_lock.count++; - return 0; - } - - if (tdb->global_lock.count) { - /* a global lock of a different type exists */ - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - } - - if (tdb->num_locks != 0) { - /* can't combine global and chain locks */ - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - } - - if (!mark_lock && - tdb->methods->tdb_brlock(tdb, FREELIST_TOP, ltype, op, - 0, 4*tdb->header.hash_size)) { - if (op == F_SETLKW) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno))); - } - return -1; - } - - tdb->global_lock.count = 1; - tdb->global_lock.ltype = ltype; - - return 0; -} - - - -/* unlock entire db */ -static int _tdb_unlockall(struct tdb_context *tdb, int ltype) -{ - bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK); - - ltype &= ~TDB_MARK_LOCK; - - /* There are no locks on read-only dbs */ - if (tdb->read_only || tdb->traverse_read) { - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - } - - if (tdb->global_lock.ltype != ltype || tdb->global_lock.count == 0) { - return TDB_ERRCODE(TDB_ERR_LOCK, -1); - } - - if (tdb->global_lock.count > 1) { - tdb->global_lock.count--; - return 0; - } - - if (!mark_lock && - tdb->methods->tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW, - 0, 4*tdb->header.hash_size)) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed (%s)\n", strerror(errno))); - return -1; - } - - tdb->global_lock.count = 0; - tdb->global_lock.ltype = 0; - - return 0; -} - -/* lock entire database with write lock */ -int tdb_lockall(struct tdb_context *tdb) -{ - return _tdb_lockall(tdb, F_WRLCK, F_SETLKW); -} - -/* lock entire database with write lock - mark only */ -int tdb_lockall_mark(struct tdb_context *tdb) -{ - return _tdb_lockall(tdb, F_WRLCK | TDB_MARK_LOCK, F_SETLKW); -} - -/* unlock entire database with write lock - unmark only */ -int tdb_lockall_unmark(struct tdb_context *tdb) -{ - return _tdb_unlockall(tdb, F_WRLCK | TDB_MARK_LOCK); -} - -/* lock entire database with write lock - nonblocking varient */ -int tdb_lockall_nonblock(struct tdb_context *tdb) -{ - return _tdb_lockall(tdb, F_WRLCK, F_SETLK); -} - -/* unlock entire database with write lock */ -int tdb_unlockall(struct tdb_context *tdb) -{ - return _tdb_unlockall(tdb, F_WRLCK); -} - -/* lock entire database with read lock */ -int tdb_lockall_read(struct tdb_context *tdb) -{ - return _tdb_lockall(tdb, F_RDLCK, F_SETLKW); -} - -/* lock entire database with read lock - nonblock varient */ -int tdb_lockall_read_nonblock(struct tdb_context *tdb) -{ - return _tdb_lockall(tdb, F_RDLCK, F_SETLK); -} - -/* unlock entire database with read lock */ -int tdb_unlockall_read(struct tdb_context *tdb) -{ - return _tdb_unlockall(tdb, F_RDLCK); -} - -/* 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) -{ - return tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK); -} - -/* 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) -{ - return tdb_lock_nonblock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK); -} - -/* 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) -{ - return tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK); -} - -/* 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) -{ - return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK); -} - -int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key) -{ - return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK); -} - -int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key) -{ - return tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK); -} - -int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA 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->global_lock.count) { - return 0; - } - return off ? tdb->methods->tdb_brlock(tdb, off, F_RDLCK, F_SETLKW, 0, 1) : 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; - return tdb->methods->tdb_brlock(tdb, off, F_WRLCK, F_SETLK, 1, 1); -} - -/* - 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_unlock_record(struct tdb_context *tdb, tdb_off_t off) -{ - return tdb->methods->tdb_brlock(tdb, off, F_UNLCK, F_SETLK, 0, 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->global_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->methods->tdb_brlock(tdb, off, F_UNLCK, F_SETLKW, 0, 1) : 0); -} |