diff options
author | Jelmer Vernooij <jelmer@samba.org> | 2008-10-21 14:51:13 +0200 |
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committer | Jelmer Vernooij <jelmer@samba.org> | 2008-10-21 14:51:13 +0200 |
commit | 5209a846a9157e649fcdcb561f7eaf19c8c0e465 (patch) | |
tree | b0a7e52b5646c8eec182dbc391e7934b6804488c /lib/tdb/common/open.c | |
parent | 625359b2e266105022309df8985720108ecd6f67 (diff) | |
parent | 2ee8d29d22bcb1c350ab59d71b0aee548489bc9c (diff) | |
download | samba-5209a846a9157e649fcdcb561f7eaf19c8c0e465.tar.gz samba-5209a846a9157e649fcdcb561f7eaf19c8c0e465.tar.bz2 samba-5209a846a9157e649fcdcb561f7eaf19c8c0e465.zip |
Merge branch 'master' of ssh://git.samba.org/data/git/samba into regsrv
Conflicts:
source4/lib/registry/ldb.c
source4/rpc_server/winreg/rpc_winreg.c
Diffstat (limited to 'lib/tdb/common/open.c')
-rw-r--r-- | lib/tdb/common/open.c | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/lib/tdb/common/open.c b/lib/tdb/common/open.c new file mode 100644 index 0000000000..b19e4cea29 --- /dev/null +++ b/lib/tdb/common/open.c @@ -0,0 +1,488 @@ + /* + 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; + + +/* This is based on the hash algorithm from gdbm */ +static unsigned int default_tdb_hash(TDB_DATA *key) +{ + uint32_t value; /* Used to compute the hash value. */ + uint32_t i; /* Used to cycle through random values. */ + + /* Set the initial value from the key size. */ + for (value = 0x238F13AF * key->dsize, i=0; i < key->dsize; i++) + value = (value + (key->dptr[i] << (i*5 % 24))); + + return (1103515243 * value + 12345); +} + + +/* initialise a new database with a specified hash size */ +static int tdb_new_database(struct tdb_context *tdb, int hash_size) +{ + struct tdb_header *newdb; + size_t size; + int ret = -1; + ssize_t written; + + /* 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))) + return TDB_ERRCODE(TDB_ERR_OOM, -1); + + /* Fill in the header */ + newdb->version = TDB_VERSION; + newdb->hash_size = hash_size; + if (tdb->flags & TDB_INTERNAL) { + tdb->map_size = size; + tdb->map_ptr = (char *)newdb; + memcpy(&tdb->header, newdb, sizeof(tdb->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; + + /* This creates an endian-converted header, as if read from disk */ + CONVERT(*newdb); + memcpy(&tdb->header, newdb, sizeof(tdb->header)); + /* Don't endian-convert the magic food! */ + memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1); + /* we still have "ret == -1" here */ + written = write(tdb->fd, newdb, size); + if (written == size) { + ret = 0; + } else if (written != -1) { + /* call write once again, this usually should return -1 and + * set errno appropriately */ + size -= written; + written = write(tdb->fd, newdb+written, size); + if (written == size) { + ret = 0; + } else if (written >= 0) { + /* a second incomplete write - we give up. + * guessing the errno... */ + errno = ENOSPC; + } + } + + 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. */ +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, ...) +{ +} + + +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) +{ + struct tdb_context *tdb; + struct stat st; + int rev = 0, locked = 0; + unsigned char *vp; + uint32_t vertest; + unsigned v; + + if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) { + /* Can't log this */ + errno = ENOMEM; + goto fail; + } + tdb_io_init(tdb); + tdb->fd = -1; + 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; + } + tdb->hash_fn = hash_fn ? hash_fn : default_tdb_hash; + + /* 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; + } + + /* 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, hash_size) != 0) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!")); + goto fail; + } + 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->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0, 1) == -1) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get global 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) && + (locked = (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_WRLCK, F_SETLK, 0, 1) == 0))) { + open_flags |= O_CREAT; + if (ftruncate(tdb->fd, 0) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: " + "failed to truncate %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by ftruncate */ + } + } + + errno = 0; + if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header) + || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0 + || (tdb->header.version != TDB_VERSION + && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION))))) { + /* its not a valid database - possibly initialise it */ + if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) { + if (errno == 0) { + errno = EIO; /* ie bad format or something */ + } + goto fail; + } + rev = (tdb->flags & TDB_CONVERT); + } + vp = (unsigned char *)&tdb->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(&tdb->header, sizeof(tdb->header)); + } + if (fstat(tdb->fd, &st) == -1) + goto fail; + + if (tdb->header.rwlocks != 0) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n")); + goto fail; + } + + /* Is it already in the open list? If so, fail. */ + if (tdb_already_open(st.st_dev, st.st_ino)) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "%s (%d,%d) is already open in this process\n", + name, (int)st.st_dev, (int)st.st_ino)); + errno = EBUSY; + goto fail; + } + + if (!(tdb->name = (char *)strdup(name))) { + errno = ENOMEM; + goto fail; + } + + tdb->map_size = st.st_size; + tdb->device = st.st_dev; + tdb->inode = st.st_ino; + tdb_mmap(tdb); + if (locked) { + if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_UNLCK, F_SETLK, 0, 1) == -1) { + TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: " + "failed to take ACTIVE_LOCK on %s: %s\n", + name, strerror(errno))); + goto fail; + } + + } + + /* 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. */ + + if (tdb_flags & TDB_CLEAR_IF_FIRST) { + /* leave this lock in place to indicate it's in use */ + if (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1) + goto fail; + } + + /* if needed, run recovery */ + if (tdb_transaction_recover(tdb) == -1) { + goto fail; + } + + internal: + /* Internal (memory-only) databases skip all the code above to + * do with disk files, and resume here by releasing their + * global lock and hooking into the active list. */ + if (tdb->methods->tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0, 1) == -1) + goto fail; + tdb->next = tdbs; + tdbs = tdb; + return tdb; + + fail: + { int save_errno = errno; + + if (!tdb) + return NULL; + + if (tdb->map_ptr) { + if (tdb->flags & TDB_INTERNAL) + SAFE_FREE(tdb->map_ptr); + else + tdb_munmap(tdb); + } + SAFE_FREE(tdb->name); + 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); + errno = save_errno; + return NULL; + } +} + +/* + * Set the maximum number of dead records per hash chain + */ + +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. + **/ +int tdb_close(struct tdb_context *tdb) +{ + struct tdb_context **i; + int ret = 0; + + if (tdb->transaction) { + tdb_transaction_cancel(tdb); + } + + if (tdb->map_ptr) { + if (tdb->flags & TDB_INTERNAL) + SAFE_FREE(tdb->map_ptr); + else + tdb_munmap(tdb); + } + SAFE_FREE(tdb->name); + if (tdb->fd != -1) + ret = close(tdb->fd); + SAFE_FREE(tdb->lockrecs); + + /* Remove from contexts list */ + for (i = &tdbs; *i; i = &(*i)->next) { + if (*i == tdb) { + *i = tdb->next; + break; + } + } + + memset(tdb, 0, sizeof(*tdb)); + SAFE_FREE(tdb); + + return ret; +} + +/* register a loging function */ +void tdb_set_logging_function(struct tdb_context *tdb, + const struct tdb_logging_context *log_ctx) +{ + tdb->log = *log_ctx; +} + +void *tdb_get_logging_private(struct tdb_context *tdb) +{ + return tdb->log.log_private; +} + +/* 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 */ +int tdb_reopen(struct tdb_context *tdb) +{ + struct stat st; + + if (tdb->flags & TDB_INTERNAL) { + return 0; /* Nothing to do. */ + } + + if (tdb->num_locks != 0 || tdb->global_lock.count) { + 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 (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; + } + if ((tdb->flags & TDB_CLEAR_IF_FIRST) && + (tdb->methods->tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0, 1) == -1)) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n")); + goto fail; + } + 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; + } + tdb_mmap(tdb); + + return 0; + +fail: + tdb_close(tdb); + return -1; +} + +/* reopen all tdb's */ +int tdb_reopen_all(int parent_longlived) +{ + struct tdb_context *tdb; + + for (tdb=tdbs; tdb; tdb = tdb->next) { + /* + * 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. */ + tdb->flags &= ~TDB_CLEAR_IF_FIRST; + } + + if (tdb_reopen(tdb) != 0) + return -1; + } + + return 0; +} |