+++ /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 "tdb1_private.h"
-
-/* list -1 is the alloc list, otherwise a hash chain. */
-static tdb1_off_t lock_offset(int list)
-{
- return TDB1_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 tdb1_open().
-
- note that a len of zero means lock to end of file
-*/
-int tdb1_brlock(struct tdb_context *tdb,
- int rw_type, tdb1_off_t offset, size_t len,
- enum tdb_lock_flags flags)
-{
- enum TDB_ERROR ecode = tdb_brlock(tdb, rw_type, offset, len, flags
- | TDB_LOCK_NOCHECK);
- if (ecode == TDB_SUCCESS)
- return 0;
- tdb->last_error = ecode;
- return -1;
-}
-
-int tdb1_brunlock(struct tdb_context *tdb,
- int rw_type, tdb1_off_t offset, size_t len)
-{
- enum TDB_ERROR ecode = tdb_brunlock(tdb, rw_type, offset, len);
- if (ecode == TDB_SUCCESS)
- return 0;
- tdb->last_error = ecode;
- return -1;
-}
-
-int tdb1_allrecord_upgrade(struct tdb_context *tdb)
-{
- enum TDB_ERROR ecode = tdb_allrecord_upgrade(tdb, TDB1_FREELIST_TOP);
- if (ecode == TDB_SUCCESS)
- return 0;
- tdb->last_error = ecode;
- return -1;
-}
-
-static struct tdb_lock *tdb1_find_nestlock(struct tdb_context *tdb,
- tdb1_off_t offset)
-{
- unsigned int i;
-
- for (i=0; i<tdb->file->num_lockrecs; i++) {
- if (tdb->file->lockrecs[i].off == offset) {
- return &tdb->file->lockrecs[i];
- }
- }
- return NULL;
-}
-
-/* lock an offset in the database. */
-int tdb1_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
- enum tdb_lock_flags flags)
-{
- enum TDB_ERROR ecode;
-
- if (offset >= lock_offset(tdb->tdb1.header.hash_size)) {
- tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb1_lock: invalid offset %u for"
- " ltype=%d",
- offset, ltype);
- return -1;
- }
-
- ecode = tdb_nest_lock(tdb, offset, ltype, flags | TDB_LOCK_NOCHECK);
- if (unlikely(ecode != TDB_SUCCESS)) {
- tdb->last_error = ecode;
- return -1;
- }
- return 0;
-}
-
-static int tdb1_lock_and_recover(struct tdb_context *tdb)
-{
- int ret;
-
- /* We need to match locking order in transaction commit. */
- if (tdb1_brlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0,
- TDB_LOCK_WAIT|TDB_LOCK_NOCHECK)) {
- return -1;
- }
-
- if (tdb1_brlock(tdb, F_WRLCK, TDB1_OPEN_LOCK, 1,
- TDB_LOCK_WAIT|TDB_LOCK_NOCHECK)) {
- tdb1_brunlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0);
- return -1;
- }
-
- ret = tdb1_transaction_recover(tdb);
-
- tdb1_brunlock(tdb, F_WRLCK, TDB1_OPEN_LOCK, 1);
- tdb1_brunlock(tdb, F_WRLCK, TDB1_FREELIST_TOP, 0);
-
- return ret;
-}
-
-static bool have_data_locks(const struct tdb_context *tdb)
-{
- unsigned int i;
-
- for (i = 0; i < tdb->file->num_lockrecs; i++) {
- if (tdb->file->lockrecs[i].off >= lock_offset(-1))
- return true;
- }
- return false;
-}
-
-static int tdb1_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->file->allrecord_lock.count) {
- if (!check_lock_pid(tdb, "tdb1_lock_list", true)) {
- tdb->last_error = TDB_ERR_LOCK;
- return -1;
- }
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb->last_error = owner_conflict(tdb, "tdb1_lock_list");
- return -1;
- }
- if (ltype == tdb->file->allrecord_lock.ltype
- || ltype == F_RDLCK) {
- return 0;
- }
- tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK,
- TDB_LOG_USE_ERROR,
- "tdb1_lock_list:"
- " already have read lock");
- return -1;
- }
-
- /* Only check when we grab first data lock. */
- check = !have_data_locks(tdb);
- ret = tdb1_nest_lock(tdb, lock_offset(list), ltype, waitflag);
-
- if (ret == 0 && check) {
- tdb_bool_err berr = tdb1_needs_recovery(tdb);
-
- if (berr < 0) {
- return -1;
- }
- if (berr == true) {
- tdb1_nest_unlock(tdb, lock_offset(list), ltype);
-
- if (tdb1_lock_and_recover(tdb) == -1) {
- return -1;
- }
- return tdb1_lock_list(tdb, list, ltype, waitflag);
- }
- }
- return ret;
-}
-
-/* lock a list in the database. list -1 is the alloc list */
-int tdb1_lock(struct tdb_context *tdb, int list, int ltype)
-{
- int ret;
-
- ret = tdb1_lock_list(tdb, list, ltype, TDB_LOCK_WAIT);
- /* Don't log for EAGAIN and EINTR: they could have overridden lock fns */
- if (ret && errno != EAGAIN && errno != EINTR) {
- tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
- "tdb1_lock failed on list %d "
- "ltype=%d (%s)", list, ltype, strerror(errno));
- }
- return ret;
-}
-
-int tdb1_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype)
-{
- enum TDB_ERROR ecode;
-
- /* Sanity checks */
- if (offset >= lock_offset(tdb->tdb1.header.hash_size)) {
- tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
- "tdb1_unlock: offset %u invalid (%d)",
- offset, tdb->tdb1.header.hash_size);
- return -1;
- }
-
- ecode = tdb_nest_unlock(tdb, offset, ltype);
- if (unlikely(ecode != TDB_SUCCESS)) {
- tdb->last_error = ecode;
- return -1;
- }
- return 0;
-}
-
-int tdb1_unlock(struct tdb_context *tdb, int list, int ltype)
-{
- /* a global lock allows us to avoid per chain locks */
- if (tdb->file->allrecord_lock.count &&
- (ltype == tdb->file->allrecord_lock.ltype || ltype == F_RDLCK)) {
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb->last_error = owner_conflict(tdb, "tdb1_unlock");
- return -1;
- }
- return 0;
- }
-
- if (tdb->file->allrecord_lock.count) {
- tdb->last_error = TDB_ERR_LOCK;
- return -1;
- }
-
- return tdb1_nest_unlock(tdb, lock_offset(list), ltype);
-}
-
-/*
- get the transaction lock
- */
-int tdb1_transaction_lock(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags lockflags)
-{
- return tdb1_nest_lock(tdb, TDB1_TRANSACTION_LOCK, ltype, lockflags);
-}
-
-/*
- release the transaction lock
- */
-int tdb1_transaction_unlock(struct tdb_context *tdb, int ltype)
-{
- return tdb1_nest_unlock(tdb, TDB1_TRANSACTION_LOCK, ltype);
-}
-
-/* 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 tdb1_allrecord_lock(struct tdb_context *tdb, int ltype,
- enum tdb_lock_flags flags, bool upgradable)
-{
- enum TDB_ERROR ecode;
- tdb_bool_err berr;
-
- /* tdb_lock_gradual() doesn't know about tdb->tdb1.traverse_read. */
- if (tdb->tdb1.traverse_read && !(tdb->flags & TDB_NOLOCK)) {
- tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK,
- TDB_LOG_USE_ERROR,
- "tdb1_allrecord_lock during"
- " tdb1_read_traverse");
- return -1;
- }
-
- if (tdb->file->allrecord_lock.count
- && tdb->file->allrecord_lock.ltype == ltype) {
- tdb->file->allrecord_lock.count++;
- return 0;
- }
-
- if (tdb1_have_extra_locks(tdb)) {
- /* can't combine global and chain locks */
- tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK,
- TDB_LOG_USE_ERROR,
- "tdb1_allrecord_lock holding"
- " other locks");
- return -1;
- }
-
- if (upgradable && ltype != F_RDLCK) {
- /* tdb error: you can't upgrade a write lock! */
- tdb->last_error = tdb_logerr(tdb, TDB_ERR_LOCK,
- TDB_LOG_ERROR,
- "tdb1_allrecord_lock cannot"
- " have upgradable write lock");
- return -1;
- }
-
- /* 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. */
- ecode = tdb_lock_gradual(tdb, ltype, flags | TDB_LOCK_NOCHECK,
- TDB1_FREELIST_TOP, tdb->tdb1.header.hash_size * 4);
- if (ecode != TDB_SUCCESS) {
- tdb->last_error = ecode;
- return -1;
- }
-
- /* Grab individual record locks. */
- if (tdb1_brlock(tdb, ltype, lock_offset(tdb->tdb1.header.hash_size), 0,
- flags) == -1) {
- tdb1_brunlock(tdb, ltype, TDB1_FREELIST_TOP,
- tdb->tdb1.header.hash_size * 4);
- return -1;
- }
-
- tdb->file->allrecord_lock.owner = tdb;
- tdb->file->allrecord_lock.count = 1;
- tdb->file->locker = getpid();
- /* 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;
-
- berr = tdb1_needs_recovery(tdb);
- if (berr < 0) {
- return -1;
- }
-
- if (berr == true) {
- tdb1_allrecord_unlock(tdb, ltype);
- if (tdb1_lock_and_recover(tdb) == -1) {
- return -1;
- }
- return tdb1_allrecord_lock(tdb, ltype, flags, upgradable);
- }
-
- return 0;
-}
-
-
-
-/* unlock entire db */
-int tdb1_allrecord_unlock(struct tdb_context *tdb, int ltype)
-{
- /* Don't try this during r/o traversal! */
- if (tdb->tdb1.traverse_read) {
- tdb->last_error = TDB_ERR_LOCK;
- return -1;
- }
-
- if (tdb->file->allrecord_lock.count == 0) {
- tdb->last_error = TDB_ERR_LOCK;
- return -1;
- }
-
- /* Upgradable locks are marked as write locks. */
- if (tdb->file->allrecord_lock.ltype != ltype
- && (!tdb->file->allrecord_lock.off || ltype != F_RDLCK)) {
- tdb->last_error = TDB_ERR_LOCK;
- return -1;
- }
-
- if (tdb->file->allrecord_lock.count > 1) {
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb->last_error
- = owner_conflict(tdb, "tdb1_allrecord_unlock");
- return -1;
- }
- tdb->file->allrecord_lock.count--;
- return 0;
- }
-
- tdb->file->allrecord_lock.count = 0;
- tdb->file->allrecord_lock.ltype = 0;
-
- if (tdb1_brunlock(tdb, ltype, TDB1_FREELIST_TOP, 0)) {
- tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
- "tdb1_unlockall failed (%s)", strerror(errno));
- return -1;
- }
-
- return 0;
-}
-
-/* lock/unlock one hash chain. This is meant to be used to reduce
- contention - it cannot guarantee how many records will be locked */
-int tdb1_chainlock(struct tdb_context *tdb, TDB_DATA key)
-{
- int ret = tdb1_lock(tdb,
- TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)),
- F_WRLCK);
- return ret;
-}
-
-int tdb1_chainunlock(struct tdb_context *tdb, TDB_DATA key)
-{
- return tdb1_unlock(tdb, TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)),
- F_WRLCK);
-}
-
-int tdb1_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
-{
- int ret;
- ret = tdb1_lock(tdb, TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)),
- F_RDLCK);
- return ret;
-}
-
-int tdb1_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
-{
- return tdb1_unlock(tdb, TDB1_BUCKET(tdb_hash(tdb, key.dptr, key.dsize)),
- F_RDLCK);
-}
-
-/* record lock stops delete underneath */
-int tdb1_lock_record(struct tdb_context *tdb, tdb1_off_t off)
-{
- if (tdb->file->allrecord_lock.count) {
- if (!check_lock_pid(tdb, "tdb1_lock_record", true)) {
- tdb->last_error = TDB_ERR_LOCK;
- return -1;
- }
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb->last_error = owner_conflict(tdb,
- "tdb1_lock_record");
- return -1;
- }
- return 0;
- }
- return off ? tdb1_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 tdb1_write_lock_record(struct tdb_context *tdb, tdb1_off_t off)
-{
- struct tdb1_traverse_lock *i;
- for (i = &tdb->tdb1.travlocks; i; i = i->next)
- if (i->off == off)
- return -1;
- if (tdb->file->allrecord_lock.count) {
- if (!check_lock_pid(tdb, "tdb1_write_lock_record", true)) {
- tdb->last_error = TDB_ERR_LOCK;
- return -1;
- }
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb->last_error
- = owner_conflict(tdb, "tdb1_write_lock_record");
- return -1;
- }
- if (tdb->file->allrecord_lock.ltype == F_WRLCK) {
- return 0;
- }
- return -1;
- }
- return tdb1_brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
-}
-
-int tdb1_write_unlock_record(struct tdb_context *tdb, tdb1_off_t off)
-{
- if (tdb->file->allrecord_lock.count) {
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb->last_error
- = owner_conflict(tdb,
- "tdb1_write_unlock_record");
- return -1;
- }
- return 0;
- }
- return tdb1_brunlock(tdb, F_WRLCK, off, 1);
-}
-
-/* fcntl locks don't stack: avoid unlocking someone else's */
-int tdb1_unlock_record(struct tdb_context *tdb, tdb1_off_t off)
-{
- struct tdb1_traverse_lock *i;
- uint32_t count = 0;
-
- if (tdb->file->allrecord_lock.count) {
- if (tdb->file->allrecord_lock.owner != tdb) {
- tdb->last_error = owner_conflict(tdb,
- "tdb1_unlock_record");
- return -1;
- }
- return 0;
- }
-
- if (off == 0)
- return 0;
- for (i = &tdb->tdb1.travlocks; i; i = i->next)
- if (i->off == off)
- count++;
- return (count == 1 ? tdb1_brunlock(tdb, F_RDLCK, off, 1) : 0);
-}
-
-bool tdb1_have_extra_locks(struct tdb_context *tdb)
-{
- unsigned int extra = tdb->file->num_lockrecs;
-
- /* A transaction holds the lock for all records. */
- if (!tdb->tdb1.transaction && tdb->file->allrecord_lock.count) {
- return true;
- }
-
- /* We always hold the active lock if CLEAR_IF_FIRST. */
- if (tdb1_find_nestlock(tdb, TDB1_ACTIVE_LOCK)) {
- extra--;
- }
-
- /* In a transaction, we expect to hold the transaction lock */
- if (tdb->tdb1.transaction
- && tdb1_find_nestlock(tdb, TDB1_TRANSACTION_LOCK)) {
- extra--;
- }
-
- return extra;
-}
-
-/* The transaction code uses this to remove all locks. */
-void tdb1_release_transaction_locks(struct tdb_context *tdb)
-{
- unsigned int i, active = 0;
-
- if (tdb->file->allrecord_lock.count != 0) {
- tdb1_brunlock(tdb, tdb->file->allrecord_lock.ltype, TDB1_FREELIST_TOP, 0);
- tdb->file->allrecord_lock.count = 0;
- }
-
- for (i=0;i<tdb->file->num_lockrecs;i++) {
- struct tdb_lock *lck = &tdb->file->lockrecs[i];
-
- /* Don't release the active lock! Copy it to first entry. */
- if (lck->off == TDB1_ACTIVE_LOCK) {
- tdb->file->lockrecs[active++] = *lck;
- } else {
- tdb1_brunlock(tdb, lck->ltype, lck->off, 1);
- }
- }
- tdb->file->num_lockrecs = active;
- if (tdb->file->num_lockrecs == 0) {
- SAFE_FREE(tdb->file->lockrecs);
- }
-}
projects / ccan / blobdiff