diff options
Diffstat (limited to 'common/open.c')
| -rw-r--r-- | common/open.c | 968 |
1 files changed, 968 insertions, 0 deletions
diff --git a/common/open.c b/common/open.c new file mode 100644 index 0000000..3fa7ce1 --- /dev/null +++ b/common/open.c @@ -0,0 +1,968 @@ + /* + 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" + +/* all contexts, to ensure no double-opens (fcntl locks don't nest!) */ +static struct tdb_context *tdbs = NULL; + +/* We use two hashes to double-check they're using the right hash function. */ +void tdb_header_hash(struct tdb_context *tdb, + uint32_t *magic1_hash, uint32_t *magic2_hash) +{ + TDB_DATA hash_key; + uint32_t tdb_magic = TDB_MAGIC; + + hash_key.dptr = discard_const_p(unsigned char, TDB_MAGIC_FOOD); + hash_key.dsize = sizeof(TDB_MAGIC_FOOD); + *magic1_hash = tdb->hash_fn(&hash_key); + + hash_key.dptr = (unsigned char *)CONVERT(tdb_magic); + hash_key.dsize = sizeof(tdb_magic); + *magic2_hash = tdb->hash_fn(&hash_key); + + /* Make sure at least one hash is non-zero! */ + if (*magic1_hash == 0 && *magic2_hash == 0) + *magic1_hash = 1; +} + +/* initialise a new database with a specified hash size */ +static int tdb_new_database(struct tdb_context *tdb, struct tdb_header *header, + int hash_size) +{ + struct tdb_header *newdb; + size_t size; + int ret = -1; + + /* We make it up in memory, then write it out if not internal */ + size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t); + if (!(newdb = (struct tdb_header *)calloc(size, 1))) { + tdb->ecode = TDB_ERR_OOM; + return -1; + } + + /* Fill in the header */ + newdb->version = TDB_VERSION; + newdb->hash_size = hash_size; + + tdb_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash); + + /* Make sure older tdbs (which don't check the magic hash fields) + * will refuse to open this TDB. */ + if (tdb->flags & TDB_INCOMPATIBLE_HASH) + newdb->rwlocks = TDB_HASH_RWLOCK_MAGIC; + + /* + * We create a tdb with TDB_FEATURE_FLAG_MUTEX support, + * the flag combination and runtime feature checks + * are done by the caller already. + */ + if (tdb->flags & TDB_MUTEX_LOCKING) { + newdb->feature_flags |= TDB_FEATURE_FLAG_MUTEX; + } + + /* + * If we have any features we add the FEATURE_FLAG_MAGIC, overwriting the + * TDB_HASH_RWLOCK_MAGIC above. + */ + if (newdb->feature_flags != 0) { + newdb->rwlocks = TDB_FEATURE_FLAG_MAGIC; + } + + /* + * It's required for some following code paths + * to have the fields on 'tdb' up-to-date. + * + * E.g. tdb_mutex_size() requires it + */ + tdb->feature_flags = newdb->feature_flags; + tdb->hash_size = newdb->hash_size; + + if (tdb->flags & TDB_INTERNAL) { + tdb->map_size = size; + tdb->map_ptr = (char *)newdb; + memcpy(header, newdb, sizeof(*header)); + /* Convert the `ondisk' version if asked. */ + CONVERT(*newdb); + return 0; + } + if (lseek(tdb->fd, 0, SEEK_SET) == -1) + goto fail; + + if (ftruncate(tdb->fd, 0) == -1) + goto fail; + + if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) { + newdb->mutex_size = tdb_mutex_size(tdb); + tdb->hdr_ofs = newdb->mutex_size; + } + + /* This creates an endian-converted header, as if read from disk */ + CONVERT(*newdb); + memcpy(header, newdb, sizeof(*header)); + /* Don't endian-convert the magic food! */ + memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1); + + if (!tdb_write_all(tdb->fd, newdb, size)) + goto fail; + + if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) { + + /* + * Now we init the mutex area + * followed by a second header. + */ + + ret = ftruncate( + tdb->fd, + newdb->mutex_size + sizeof(struct tdb_header)); + if (ret == -1) { + goto fail; + } + ret = tdb_mutex_init(tdb); + if (ret == -1) { + goto fail; + } + + /* + * Write a second header behind the mutexes. That's the area + * that will be mmapp'ed. + */ + ret = lseek(tdb->fd, newdb->mutex_size, SEEK_SET); + if (ret == -1) { + goto fail; + } + if (!tdb_write_all(tdb->fd, newdb, size)) { + goto fail; + } + } + + ret = 0; + fail: + SAFE_FREE(newdb); + return ret; +} + + + +static int tdb_already_open(dev_t device, + ino_t ino) +{ + struct tdb_context *i; + + for (i = tdbs; i; i = i->next) { + if (i->device == device && i->inode == ino) { + return 1; + } + } + + return 0; +} + +/* open the database, creating it if necessary + + The open_flags and mode are passed straight to the open call on the + database file. A flags value of O_WRONLY is invalid. The hash size + is advisory, use zero for a default value. + + Return is NULL on error, in which case errno is also set. Don't + try to call tdb_error or tdb_errname, just do strerror(errno). + + @param name may be NULL for internal databases. */ +_PUBLIC_ struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags, + int open_flags, mode_t mode) +{ + return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL, NULL); +} + +/* a default logging function */ +static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4); +static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) +{ +} + +static bool check_header_hash(struct tdb_context *tdb, + struct tdb_header *header, + bool default_hash, uint32_t *m1, uint32_t *m2) +{ + tdb_header_hash(tdb, m1, m2); + if (header->magic1_hash == *m1 && + header->magic2_hash == *m2) { + return true; + } + + /* If they explicitly set a hash, always respect it. */ + if (!default_hash) + return false; + + /* Otherwise, try the other inbuilt hash. */ + if (tdb->hash_fn == tdb_old_hash) + tdb->hash_fn = tdb_jenkins_hash; + else + tdb->hash_fn = tdb_old_hash; + return check_header_hash(tdb, header, false, m1, m2); +} + +static bool tdb_mutex_open_ok(struct tdb_context *tdb, + const struct tdb_header *header) +{ + if (tdb->flags & TDB_NOLOCK) { + /* + * We don't look at locks, so it does not matter to have a + * compatible mutex implementation. Allow the open. + */ + return true; + } + + if (!(tdb->flags & TDB_MUTEX_LOCKING)) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: " + "Can use mutexes only with " + "MUTEX_LOCKING or NOLOCK\n", + tdb->name)); + return false; + } + + if (tdb_mutex_size(tdb) != header->mutex_size) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: " + "Mutex size changed from %"PRIu32" to %zu\n.", + tdb->name, + header->mutex_size, + tdb_mutex_size(tdb))); + return false; + } + + return true; +} + +_PUBLIC_ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags, + int open_flags, mode_t mode, + const struct tdb_logging_context *log_ctx, + tdb_hash_func hash_fn) +{ + int orig_errno = errno; + struct tdb_header header = { + .version = 0, + }; + struct tdb_context *tdb; + struct stat st; + int rev = 0; + bool locked = false; + unsigned char *vp; + uint32_t vertest; + unsigned v; + const char *hash_alg; + uint32_t magic1, magic2; + int ret; + + if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) { + /* Can't log this */ + errno = ENOMEM; + goto fail; + } + tdb_io_init(tdb); + + if (tdb_flags & TDB_INTERNAL) { + tdb_flags |= TDB_INCOMPATIBLE_HASH; + } + if (tdb_flags & TDB_MUTEX_LOCKING) { + tdb_flags |= TDB_INCOMPATIBLE_HASH; + } + + tdb->fd = -1; +#ifdef TDB_TRACE + tdb->tracefd = -1; +#endif + tdb->name = NULL; + tdb->map_ptr = NULL; + tdb->flags = tdb_flags; + tdb->open_flags = open_flags; + if (log_ctx) { + tdb->log = *log_ctx; + } else { + tdb->log.log_fn = null_log_fn; + tdb->log.log_private = NULL; + } + + if (name == NULL && (tdb_flags & TDB_INTERNAL)) { + name = "__TDB_INTERNAL__"; + } + + if (name == NULL) { + tdb->name = discard_const_p(char, "__NULL__"); + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: called with name == NULL\n")); + tdb->name = NULL; + errno = EINVAL; + goto fail; + } + + /* now make a copy of the name, as the caller memory might go away */ + if (!(tdb->name = (char *)strdup(name))) { + /* + * set the name as the given string, so that tdb_name() will + * work in case of an error. + */ + tdb->name = discard_const_p(char, name); + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't strdup(%s)\n", + name)); + tdb->name = NULL; + errno = ENOMEM; + goto fail; + } + + if (hash_fn) { + tdb->hash_fn = hash_fn; + hash_alg = "the user defined"; + } else { + /* This controls what we use when creating a tdb. */ + if (tdb->flags & TDB_INCOMPATIBLE_HASH) { + tdb->hash_fn = tdb_jenkins_hash; + } else { + tdb->hash_fn = tdb_old_hash; + } + hash_alg = "either default"; + } + + /* cache the page size */ + tdb->page_size = getpagesize(); + if (tdb->page_size <= 0) { + tdb->page_size = 0x2000; + } + + tdb->max_dead_records = (tdb_flags & TDB_VOLATILE) ? 5 : 0; + + if ((open_flags & O_ACCMODE) == O_WRONLY) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n", + name)); + errno = EINVAL; + goto fail; + } + + if (hash_size == 0) + hash_size = DEFAULT_HASH_SIZE; + if ((open_flags & O_ACCMODE) == O_RDONLY) { + tdb->read_only = 1; + /* read only databases don't do locking or clear if first */ + tdb->flags |= TDB_NOLOCK; + tdb->flags &= ~(TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING); + } + + if ((tdb->flags & TDB_ALLOW_NESTING) && + (tdb->flags & TDB_DISALLOW_NESTING)) { + tdb->ecode = TDB_ERR_NESTING; + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "allow_nesting and disallow_nesting are not allowed together!")); + errno = EINVAL; + goto fail; + } + + if (tdb->flags & TDB_MUTEX_LOCKING) { + /* + * Here we catch bugs in the callers, + * the runtime check for existing tdb's comes later. + */ + + if (tdb->flags & TDB_INTERNAL) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "invalid flags for %s - TDB_MUTEX_LOCKING and " + "TDB_INTERNAL are not allowed together\n", name)); + errno = EINVAL; + goto fail; + } + + if (tdb->flags & TDB_NOMMAP) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "invalid flags for %s - TDB_MUTEX_LOCKING and " + "TDB_NOMMAP are not allowed together\n", name)); + errno = EINVAL; + goto fail; + } + + if (tdb->read_only) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "invalid flags for %s - TDB_MUTEX_LOCKING " + "not allowed read only\n", name)); + errno = EINVAL; + goto fail; + } + + /* + * The callers should have called + * tdb_runtime_check_for_robust_mutexes() + * before using TDB_MUTEX_LOCKING! + * + * This makes sure the caller understands + * that the locking may behave a bit differently + * than with pure fcntl locking. E.g. multiple + * read locks are not supported. + */ + if (!tdb_runtime_check_for_robust_mutexes()) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "invalid flags for %s - TDB_MUTEX_LOCKING " + "requires support for robust_mutexes\n", + name)); + errno = ENOSYS; + goto fail; + } + } + + if (getenv("TDB_NO_FSYNC")) { + tdb->flags |= TDB_NOSYNC; + } + + /* + * TDB_ALLOW_NESTING is the default behavior. + * Note: this may change in future versions! + */ + if (!(tdb->flags & TDB_DISALLOW_NESTING)) { + tdb->flags |= TDB_ALLOW_NESTING; + } + + /* internal databases don't mmap or lock, and start off cleared */ + if (tdb->flags & TDB_INTERNAL) { + tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP); + tdb->flags &= ~TDB_CLEAR_IF_FIRST; + if (tdb_new_database(tdb, &header, hash_size) != 0) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!")); + goto fail; + } + tdb->hash_size = hash_size; + goto internal; + } + + if ((tdb->fd = open(name, open_flags, mode)) == -1) { + TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by open(2) */ + } + + /* on exec, don't inherit the fd */ + v = fcntl(tdb->fd, F_GETFD, 0); + fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC); + + /* ensure there is only one process initialising at once */ + if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get open lock on %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by tdb_brlock */ + } + + /* we need to zero database if we are the only one with it open */ + if ((tdb_flags & TDB_CLEAR_IF_FIRST) && + (!tdb->read_only)) { + ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK, + TDB_LOCK_NOWAIT|TDB_LOCK_PROBE); + locked = (ret == 0); + + if (locked) { + ret = tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0, + TDB_LOCK_WAIT); + if (ret == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "tdb_brlock failed for %s: %s\n", + name, strerror(errno))); + goto fail; + } + ret = tdb_new_database(tdb, &header, hash_size); + if (ret == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "tdb_new_database failed for " + "%s: %s\n", name, strerror(errno))); + tdb_unlockall(tdb); + goto fail; + } + ret = tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0); + if (ret == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "tdb_unlockall failed for %s: %s\n", + name, strerror(errno))); + goto fail; + } + ret = lseek(tdb->fd, 0, SEEK_SET); + if (ret == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "lseek failed for %s: %s\n", + name, strerror(errno))); + goto fail; + } + } + } + + errno = 0; + if (read(tdb->fd, &header, sizeof(header)) != sizeof(header) + /* + * Call strncmp() rather than strcmp() in case header.magic_food is + * not zero‐terminated. We’re still checking the full string for + * equality, as tdb_header::magic_food is larger than + * TDB_MAGIC_FOOD. + */ + || strncmp(header.magic_food, TDB_MAGIC_FOOD, sizeof(header.magic_food)) != 0) { + if (!(open_flags & O_CREAT) || + tdb_new_database(tdb, &header, hash_size) == -1) { + if (errno == 0) { + errno = EIO; /* ie bad format or something */ + } + goto fail; + } + rev = (tdb->flags & TDB_CONVERT); + } else if (header.version != TDB_VERSION + && !(rev = (header.version==TDB_BYTEREV(TDB_VERSION)))) { + /* wrong version */ + errno = EIO; + goto fail; + } + vp = (unsigned char *)&header.version; + vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) | + (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3]; + tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0; + if (!rev) + tdb->flags &= ~TDB_CONVERT; + else { + tdb->flags |= TDB_CONVERT; + tdb_convert(&header, sizeof(header)); + } + + /* + * We only use st.st_dev and st.st_ino from the raw fstat() + * call, everything else needs to use tdb_fstat() in order + * to skip tdb->hdr_ofs! + */ + if (fstat(tdb->fd, &st) == -1) { + goto fail; + } + tdb->device = st.st_dev; + tdb->inode = st.st_ino; + ZERO_STRUCT(st); + + if (header.rwlocks != 0 && + header.rwlocks != TDB_FEATURE_FLAG_MAGIC && + header.rwlocks != TDB_HASH_RWLOCK_MAGIC) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n")); + errno = ENOSYS; + goto fail; + } + + if (header.hash_size == 0) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: invalid database: 0 hash_size\n")); + errno = ENOSYS; + goto fail; + } + + tdb->hash_size = header.hash_size; + + if (header.rwlocks == TDB_FEATURE_FLAG_MAGIC) { + tdb->feature_flags = header.feature_flags; + } + + if (tdb->feature_flags & ~TDB_SUPPORTED_FEATURE_FLAGS) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: unsupported " + "features in tdb %s: 0x%08x (supported: 0x%08x)\n", + name, (unsigned)tdb->feature_flags, + (unsigned)TDB_SUPPORTED_FEATURE_FLAGS)); + errno = ENOSYS; + goto fail; + } + + if (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) { + if (!tdb_mutex_open_ok(tdb, &header)) { + errno = EINVAL; + goto fail; + } + + /* + * We need to remember the hdr_ofs + * also for the TDB_NOLOCK case + * if the current library doesn't support + * mutex locking. + */ + tdb->hdr_ofs = header.mutex_size; + + if ((!(tdb_flags & TDB_CLEAR_IF_FIRST)) && (!tdb->read_only)) { + /* + * Open an existing mutexed tdb, but without + * CLEAR_IF_FIRST. We need to initialize the + * mutex array and keep the CLEAR_IF_FIRST + * lock locked. + */ + ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK, + TDB_LOCK_NOWAIT|TDB_LOCK_PROBE); + locked = (ret == 0); + + if (locked) { + ret = tdb_mutex_init(tdb); + if (ret == -1) { + TDB_LOG((tdb, + TDB_DEBUG_FATAL, + "tdb_open_ex: tdb_mutex_init " + "failed for ""%s: %s\n", + name, strerror(errno))); + goto fail; + } + } + } + } + + if ((header.magic1_hash == 0) && (header.magic2_hash == 0)) { + /* older TDB without magic hash references */ + tdb->hash_fn = tdb_old_hash; + } else if (!check_header_hash(tdb, &header, !hash_fn, + &magic1, &magic2)) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "%s was not created with %s hash function we are using\n" + "magic1_hash[0x%08X %s 0x%08X] " + "magic2_hash[0x%08X %s 0x%08X]\n", + name, hash_alg, + header.magic1_hash, + (header.magic1_hash == magic1) ? "==" : "!=", + magic1, + header.magic2_hash, + (header.magic2_hash == magic2) ? "==" : "!=", + magic2)); + errno = EINVAL; + goto fail; + } + + /* Is it already in the open list? If so, fail. */ + if (tdb_already_open(tdb->device, tdb->inode)) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "%s (%d,%d) is already open in this process\n", + name, (int)tdb->device, (int)tdb->inode)); + errno = EBUSY; + goto fail; + } + + /* + * We had tdb_mmap(tdb) here before, + * but we need to use tdb_fstat(), + * which is triggered from tdb_oob() before calling tdb_mmap(). + * As this skips tdb->hdr_ofs. + */ + tdb->map_size = 0; + ret = tdb_oob(tdb, 0, 1, 0); + if (ret == -1) { + errno = EIO; + goto fail; + } + + if (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) { + if (!(tdb->flags & TDB_NOLOCK)) { + ret = tdb_mutex_mmap(tdb); + if (ret != 0) { + goto fail; + } + } + } + + if (tdb->hash_size > UINT32_MAX/4) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "hash size %"PRIu32" too large\n", tdb->hash_size)); + errno = EINVAL; + goto fail; + } + + ret = tdb_oob(tdb, FREELIST_TOP, 4*tdb->hash_size, 1); + if (ret == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "hash size %"PRIu32" does not fit\n", tdb->hash_size)); + errno = EINVAL; + goto fail; + } + + if (locked) { + if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "failed to release ACTIVE_LOCK on %s: %s\n", + name, strerror(errno))); + goto fail; + } + + + } + + if (locked || (tdb_flags & TDB_CLEAR_IF_FIRST)) { + /* + * We always need to do this if the CLEAR_IF_FIRST + * flag is set, even if we didn't get the initial + * exclusive lock as we need to let all other users + * know we're using it. + */ + + ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT); + if (ret == -1) { + goto fail; + } + } + + /* if needed, run recovery */ + if (tdb_transaction_recover(tdb) == -1) { + goto fail; + } + +#ifdef TDB_TRACE + { + char tracefile[strlen(name) + 32]; + + snprintf(tracefile, sizeof(tracefile), + "%s.trace.%li", name, (long)getpid()); + tdb->tracefd = open(tracefile, O_WRONLY|O_CREAT|O_EXCL, 0600); + if (tdb->tracefd >= 0) { + tdb_enable_seqnum(tdb); + tdb_trace_open(tdb, "tdb_open", hash_size, tdb_flags, + open_flags); + } else + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to open trace file %s!\n", tracefile)); + } +#endif + + internal: + /* Internal (memory-only) databases skip all the code above to + * do with disk files, and resume here by releasing their + * open lock and hooking into the active list. */ + if (tdb_nest_unlock(tdb, OPEN_LOCK, F_WRLCK, false) == -1) { + goto fail; + } + tdb->next = tdbs; + tdbs = tdb; + errno = orig_errno; + return tdb; + + fail: + { int save_errno = errno; + + if (!tdb) + return NULL; + +#ifdef TDB_TRACE + close(tdb->tracefd); +#endif + if (tdb->map_ptr) { + if (tdb->flags & TDB_INTERNAL) + SAFE_FREE(tdb->map_ptr); + else + tdb_munmap(tdb); + } + if (tdb->fd != -1) + if (close(tdb->fd) != 0) + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n")); + SAFE_FREE(tdb->lockrecs); + SAFE_FREE(tdb->name); + SAFE_FREE(tdb); + errno = save_errno; + return NULL; + } +} + +/* + * Set the maximum number of dead records per hash chain + */ + +_PUBLIC_ void tdb_set_max_dead(struct tdb_context *tdb, int max_dead) +{ + tdb->max_dead_records = max_dead; +} + +/** + * Close a database. + * + * @returns -1 for error; 0 for success. + **/ +_PUBLIC_ int tdb_close(struct tdb_context *tdb) +{ + struct tdb_context **i; + int ret = 0; + + if (tdb->transaction) { + tdb_transaction_cancel(tdb); + } + tdb_trace(tdb, "tdb_close"); + + if (tdb->map_ptr) { + if (tdb->flags & TDB_INTERNAL) + SAFE_FREE(tdb->map_ptr); + else + tdb_munmap(tdb); + } + + tdb_mutex_munmap(tdb); + + SAFE_FREE(tdb->name); + if (tdb->fd != -1) { + ret = close(tdb->fd); + tdb->fd = -1; + } + SAFE_FREE(tdb->lockrecs); + + /* Remove from contexts list */ + for (i = &tdbs; *i; i = &(*i)->next) { + if (*i == tdb) { + *i = tdb->next; + break; + } + } + +#ifdef TDB_TRACE + close(tdb->tracefd); +#endif + memset(tdb, 0, sizeof(*tdb)); + SAFE_FREE(tdb); + + return ret; +} + +/* register a logging function */ +_PUBLIC_ void tdb_set_logging_function(struct tdb_context *tdb, + const struct tdb_logging_context *log_ctx) +{ + tdb->log = *log_ctx; +} + +_PUBLIC_ void *tdb_get_logging_private(struct tdb_context *tdb) +{ + return tdb->log.log_private; +} + +static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock) +{ +#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \ + !defined(LIBREPLACE_PWRITE_NOT_REPLACED) + struct stat st; +#endif + + if (tdb->flags & TDB_INTERNAL) { + return 0; /* Nothing to do. */ + } + + if (tdb_have_extra_locks(tdb)) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n")); + goto fail; + } + + if (tdb->transaction != 0) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n")); + goto fail; + } + +/* If we have real pread & pwrite, we can skip reopen. */ +#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \ + !defined(LIBREPLACE_PWRITE_NOT_REPLACED) + if (tdb_munmap(tdb) != 0) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno))); + goto fail; + } + if (close(tdb->fd) != 0) + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: WARNING closing tdb->fd failed!\n")); + tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0); + if (tdb->fd == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: open failed (%s)\n", strerror(errno))); + goto fail; + } + /* + * We only use st.st_dev and st.st_ino from the raw fstat() + * call, everything else needs to use tdb_fstat() in order + * to skip tdb->hdr_ofs! + */ + if (fstat(tdb->fd, &st) != 0) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: fstat failed (%s)\n", strerror(errno))); + goto fail; + } + if (st.st_ino != tdb->inode || st.st_dev != tdb->device) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: file dev/inode has changed!\n")); + goto fail; + } + ZERO_STRUCT(st); + + /* + * We had tdb_mmap(tdb) here before, + * but we need to use tdb_fstat(), + * which is triggered from tdb_oob() before calling tdb_mmap(). + * As this skips tdb->hdr_ofs. + */ + tdb->map_size = 0; + if (tdb_oob(tdb, 0, 1, 0) != 0) { + goto fail; + } +#endif /* fake pread or pwrite */ + + /* We may still think we hold the active lock. */ + tdb->num_lockrecs = 0; + SAFE_FREE(tdb->lockrecs); + tdb->lockrecs_array_length = 0; + + if (active_lock && tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n")); + goto fail; + } + + return 0; + +fail: + tdb_close(tdb); + return -1; +} + +/* reopen a tdb - this can be used after a fork to ensure that we have an independent + seek pointer from our parent and to re-establish locks */ +_PUBLIC_ int tdb_reopen(struct tdb_context *tdb) +{ + bool active_lock; + active_lock = (tdb->flags & (TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING)); + + return tdb_reopen_internal(tdb, active_lock); +} + +/* reopen all tdb's */ +_PUBLIC_ int tdb_reopen_all(int parent_longlived) +{ + struct tdb_context *tdb; + + for (tdb=tdbs; tdb; tdb = tdb->next) { + bool active_lock; + + active_lock = + (tdb->flags & (TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING)); + + /* + * If the parent is longlived (ie. a + * parent daemon architecture), we know + * it will keep it's active lock on a + * tdb opened with CLEAR_IF_FIRST. Thus + * for child processes we don't have to + * add an active lock. This is essential + * to improve performance on systems that + * keep POSIX locks as a non-scalable data + * structure in the kernel. + */ + if (parent_longlived) { + /* Ensure no clear-if-first. */ + active_lock = false; + } + + if (tdb_reopen_internal(tdb, active_lock) != 0) + return -1; + } + + return 0; +} |