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-rw-r--r--tdb/common/open.c488
1 files changed, 488 insertions, 0 deletions
diff --git a/tdb/common/open.c b/tdb/common/open.c
new file mode 100644
index 0000000000..b19e4cea29
--- /dev/null
+++ b/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;
+}
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