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-rw-r--r--source3/tdb/common/tdb.c431
1 files changed, 431 insertions, 0 deletions
diff --git a/source3/tdb/common/tdb.c b/source3/tdb/common/tdb.c
new file mode 100644
index 0000000000..524d404a50
--- /dev/null
+++ b/source3/tdb/common/tdb.c
@@ -0,0 +1,431 @@
+ /*
+ 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 2 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, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include "tdb_private.h"
+
+TDB_DATA tdb_null;
+
+/*
+ increment the tdb sequence number if the tdb has been opened using
+ the TDB_SEQNUM flag
+*/
+static void tdb_increment_seqnum(struct tdb_context *tdb)
+{
+ tdb_off_t seqnum=0;
+
+ if (!(tdb->flags & TDB_SEQNUM)) {
+ return;
+ }
+
+ if (tdb_brlock(tdb, TDB_SEQNUM_OFS, F_WRLCK, F_SETLKW, 1) != 0) {
+ return;
+ }
+
+ /* we ignore errors from this, as we have no sane way of
+ dealing with them.
+ */
+ tdb_ofs_read(tdb, TDB_SEQNUM_OFS, &seqnum);
+ seqnum++;
+ tdb_ofs_write(tdb, TDB_SEQNUM_OFS, &seqnum);
+
+ tdb_brlock(tdb, TDB_SEQNUM_OFS, F_UNLCK, F_SETLKW, 1);
+}
+
+
+/* Returns 0 on fail. On success, return offset of record, and fills
+ in rec */
+static tdb_off_t tdb_find(struct tdb_context *tdb, TDB_DATA key, u32 hash,
+ struct list_struct *r)
+{
+ tdb_off_t rec_ptr;
+
+ /* read in the hash top */
+ if (tdb_ofs_read(tdb, TDB_HASH_TOP(hash), &rec_ptr) == -1)
+ return 0;
+
+ /* keep looking until we find the right record */
+ while (rec_ptr) {
+ if (tdb_rec_read(tdb, rec_ptr, r) == -1)
+ return 0;
+
+ if (!TDB_DEAD(r) && hash==r->full_hash && key.dsize==r->key_len) {
+ char *k;
+ /* a very likely hit - read the key */
+ k = tdb_alloc_read(tdb, rec_ptr + sizeof(*r),
+ r->key_len);
+ if (!k)
+ return 0;
+
+ if (memcmp(key.dptr, k, key.dsize) == 0) {
+ SAFE_FREE(k);
+ return rec_ptr;
+ }
+ SAFE_FREE(k);
+ }
+ rec_ptr = r->next;
+ }
+ return TDB_ERRCODE(TDB_ERR_NOEXIST, 0);
+}
+
+/* As tdb_find, but if you succeed, keep the lock */
+tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, u32 hash, int locktype,
+ struct list_struct *rec)
+{
+ u32 rec_ptr;
+
+ if (tdb_lock(tdb, BUCKET(hash), locktype) == -1)
+ return 0;
+ if (!(rec_ptr = tdb_find(tdb, key, hash, rec)))
+ tdb_unlock(tdb, BUCKET(hash), locktype);
+ return rec_ptr;
+}
+
+
+/* update an entry in place - this only works if the new data size
+ is <= the old data size and the key exists.
+ on failure return -1.
+*/
+static int tdb_update_hash(struct tdb_context *tdb, TDB_DATA key, u32 hash, TDB_DATA dbuf)
+{
+ struct list_struct rec;
+ tdb_off_t rec_ptr;
+
+ /* find entry */
+ if (!(rec_ptr = tdb_find(tdb, key, hash, &rec)))
+ return -1;
+
+ /* must be long enough key, data and tailer */
+ if (rec.rec_len < key.dsize + dbuf.dsize + sizeof(tdb_off_t)) {
+ tdb->ecode = TDB_SUCCESS; /* Not really an error */
+ return -1;
+ }
+
+ if (tdb->methods->tdb_write(tdb, rec_ptr + sizeof(rec) + rec.key_len,
+ dbuf.dptr, dbuf.dsize) == -1)
+ return -1;
+
+ if (dbuf.dsize != rec.data_len) {
+ /* update size */
+ rec.data_len = dbuf.dsize;
+ return tdb_rec_write(tdb, rec_ptr, &rec);
+ }
+
+ return 0;
+}
+
+/* find an entry in the database given a key */
+/* If an entry doesn't exist tdb_err will be set to
+ * TDB_ERR_NOEXIST. If a key has no data attached
+ * then the TDB_DATA will have zero length but
+ * a non-zero pointer
+ */
+TDB_DATA tdb_fetch(struct tdb_context *tdb, TDB_DATA key)
+{
+ tdb_off_t rec_ptr;
+ struct list_struct rec;
+ TDB_DATA ret;
+ u32 hash;
+
+ /* find which hash bucket it is in */
+ hash = tdb->hash_fn(&key);
+ if (!(rec_ptr = tdb_find_lock_hash(tdb,key,hash,F_RDLCK,&rec)))
+ return tdb_null;
+
+ ret.dptr = tdb_alloc_read(tdb, rec_ptr + sizeof(rec) + rec.key_len,
+ rec.data_len);
+ ret.dsize = rec.data_len;
+ tdb_unlock(tdb, BUCKET(rec.full_hash), F_RDLCK);
+ return ret;
+}
+
+/* check if an entry in the database exists
+
+ note that 1 is returned if the key is found and 0 is returned if not found
+ this doesn't match the conventions in the rest of this module, but is
+ compatible with gdbm
+*/
+static int tdb_exists_hash(struct tdb_context *tdb, TDB_DATA key, u32 hash)
+{
+ struct list_struct rec;
+
+ if (tdb_find_lock_hash(tdb, key, hash, F_RDLCK, &rec) == 0)
+ return 0;
+ tdb_unlock(tdb, BUCKET(rec.full_hash), F_RDLCK);
+ return 1;
+}
+
+int tdb_exists(struct tdb_context *tdb, TDB_DATA key)
+{
+ u32 hash = tdb->hash_fn(&key);
+ return tdb_exists_hash(tdb, key, hash);
+}
+
+/* actually delete an entry in the database given the offset */
+int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct list_struct*rec)
+{
+ tdb_off_t last_ptr, i;
+ struct list_struct lastrec;
+
+ if (tdb->read_only || tdb->traverse_read) return -1;
+
+ if (tdb_write_lock_record(tdb, rec_ptr) == -1) {
+ /* Someone traversing here: mark it as dead */
+ rec->magic = TDB_DEAD_MAGIC;
+ return tdb_rec_write(tdb, rec_ptr, rec);
+ }
+ if (tdb_write_unlock_record(tdb, rec_ptr) != 0)
+ return -1;
+
+ /* find previous record in hash chain */
+ if (tdb_ofs_read(tdb, TDB_HASH_TOP(rec->full_hash), &i) == -1)
+ return -1;
+ for (last_ptr = 0; i != rec_ptr; last_ptr = i, i = lastrec.next)
+ if (tdb_rec_read(tdb, i, &lastrec) == -1)
+ return -1;
+
+ /* unlink it: next ptr is at start of record. */
+ if (last_ptr == 0)
+ last_ptr = TDB_HASH_TOP(rec->full_hash);
+ if (tdb_ofs_write(tdb, last_ptr, &rec->next) == -1)
+ return -1;
+
+ /* recover the space */
+ if (tdb_free(tdb, rec_ptr, rec) == -1)
+ return -1;
+ return 0;
+}
+
+/* delete an entry in the database given a key */
+static int tdb_delete_hash(struct tdb_context *tdb, TDB_DATA key, u32 hash)
+{
+ tdb_off_t rec_ptr;
+ struct list_struct rec;
+ int ret;
+
+ if (!(rec_ptr = tdb_find_lock_hash(tdb, key, hash, F_WRLCK, &rec)))
+ return -1;
+ ret = tdb_do_delete(tdb, rec_ptr, &rec);
+
+ if (ret == 0) {
+ tdb_increment_seqnum(tdb);
+ }
+
+ if (tdb_unlock(tdb, BUCKET(rec.full_hash), F_WRLCK) != 0)
+ TDB_LOG((tdb, 0, "tdb_delete: WARNING tdb_unlock failed!\n"));
+ return ret;
+}
+
+int tdb_delete(struct tdb_context *tdb, TDB_DATA key)
+{
+ u32 hash = tdb->hash_fn(&key);
+ return tdb_delete_hash(tdb, key, hash);
+}
+
+/* store an element in the database, replacing any existing element
+ with the same key
+
+ return 0 on success, -1 on failure
+*/
+int tdb_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, int flag)
+{
+ struct list_struct rec;
+ u32 hash;
+ tdb_off_t rec_ptr;
+ char *p = NULL;
+ int ret = 0;
+
+ if (tdb->read_only || tdb->traverse_read) {
+ tdb->ecode = TDB_ERR_RDONLY;
+ return -1;
+ }
+
+ /* find which hash bucket it is in */
+ hash = tdb->hash_fn(&key);
+ if (tdb_lock(tdb, BUCKET(hash), F_WRLCK) == -1)
+ return -1;
+
+ /* check for it existing, on insert. */
+ if (flag == TDB_INSERT) {
+ if (tdb_exists_hash(tdb, key, hash)) {
+ tdb->ecode = TDB_ERR_EXISTS;
+ goto fail;
+ }
+ } else {
+ /* first try in-place update, on modify or replace. */
+ if (tdb_update_hash(tdb, key, hash, dbuf) == 0)
+ goto out;
+ if (tdb->ecode == TDB_ERR_NOEXIST &&
+ flag == TDB_MODIFY) {
+ /* if the record doesn't exist and we are in TDB_MODIFY mode then
+ we should fail the store */
+ goto fail;
+ }
+ }
+ /* reset the error code potentially set by the tdb_update() */
+ tdb->ecode = TDB_SUCCESS;
+
+ /* delete any existing record - if it doesn't exist we don't
+ care. Doing this first reduces fragmentation, and avoids
+ coalescing with `allocated' block before it's updated. */
+ if (flag != TDB_INSERT)
+ tdb_delete_hash(tdb, key, hash);
+
+ /* Copy key+value *before* allocating free space in case malloc
+ fails and we are left with a dead spot in the tdb. */
+
+ if (!(p = (char *)malloc(key.dsize + dbuf.dsize))) {
+ tdb->ecode = TDB_ERR_OOM;
+ goto fail;
+ }
+
+ memcpy(p, key.dptr, key.dsize);
+ if (dbuf.dsize)
+ memcpy(p+key.dsize, dbuf.dptr, dbuf.dsize);
+
+ /* we have to allocate some space */
+ if (!(rec_ptr = tdb_allocate(tdb, key.dsize + dbuf.dsize, &rec)))
+ goto fail;
+
+ /* Read hash top into next ptr */
+ if (tdb_ofs_read(tdb, TDB_HASH_TOP(hash), &rec.next) == -1)
+ goto fail;
+
+ rec.key_len = key.dsize;
+ rec.data_len = dbuf.dsize;
+ rec.full_hash = hash;
+ rec.magic = TDB_MAGIC;
+
+ /* write out and point the top of the hash chain at it */
+ if (tdb_rec_write(tdb, rec_ptr, &rec) == -1
+ || tdb->methods->tdb_write(tdb, rec_ptr+sizeof(rec), p, key.dsize+dbuf.dsize)==-1
+ || tdb_ofs_write(tdb, TDB_HASH_TOP(hash), &rec_ptr) == -1) {
+ /* Need to tdb_unallocate() here */
+ goto fail;
+ }
+
+ tdb_increment_seqnum(tdb);
+
+ out:
+ SAFE_FREE(p);
+ tdb_unlock(tdb, BUCKET(hash), F_WRLCK);
+ return ret;
+fail:
+ ret = -1;
+ goto out;
+}
+
+
+/* Append to an entry. Create if not exist. */
+int tdb_append(struct tdb_context *tdb, TDB_DATA key, TDB_DATA new_dbuf)
+{
+ u32 hash;
+ TDB_DATA dbuf;
+ int ret = -1;
+
+ /* find which hash bucket it is in */
+ hash = tdb->hash_fn(&key);
+ if (tdb_lock(tdb, BUCKET(hash), F_WRLCK) == -1)
+ return -1;
+
+ dbuf = tdb_fetch(tdb, key);
+
+ if (dbuf.dptr == NULL) {
+ dbuf.dptr = (char *)malloc(new_dbuf.dsize);
+ } else {
+ dbuf.dptr = (char *)realloc(dbuf.dptr,
+ dbuf.dsize + new_dbuf.dsize);
+ }
+
+ if (dbuf.dptr == NULL) {
+ tdb->ecode = TDB_ERR_OOM;
+ goto failed;
+ }
+
+ memcpy(dbuf.dptr + dbuf.dsize, new_dbuf.dptr, new_dbuf.dsize);
+ dbuf.dsize += new_dbuf.dsize;
+
+ ret = tdb_store(tdb, key, dbuf, 0);
+
+failed:
+ tdb_unlock(tdb, BUCKET(hash), F_WRLCK);
+ SAFE_FREE(dbuf.dptr);
+ return ret;
+}
+
+
+/*
+ return the name of the current tdb file
+ useful for external logging functions
+*/
+const char *tdb_name(struct tdb_context *tdb)
+{
+ return tdb->name;
+}
+
+/*
+ return the underlying file descriptor being used by tdb, or -1
+ useful for external routines that want to check the device/inode
+ of the fd
+*/
+int tdb_fd(struct tdb_context *tdb)
+{
+ return tdb->fd;
+}
+
+/*
+ return the current logging function
+ useful for external tdb routines that wish to log tdb errors
+*/
+tdb_log_func tdb_log_fn(struct tdb_context *tdb)
+{
+ return tdb->log_fn;
+}
+
+
+/*
+ get the tdb sequence number. Only makes sense if the writers opened
+ with TDB_SEQNUM set. Note that this sequence number will wrap quite
+ quickly, so it should only be used for a 'has something changed'
+ test, not for code that relies on the count of the number of changes
+ made. If you want a counter then use a tdb record.
+
+ The aim of this sequence number is to allow for a very lightweight
+ test of a possible tdb change.
+*/
+int tdb_get_seqnum(struct tdb_context *tdb)
+{
+ tdb_off_t seqnum=0;
+
+ tdb_ofs_read(tdb, TDB_SEQNUM_OFS, &seqnum);
+ return seqnum;
+}
+
+int tdb_hash_size(struct tdb_context *tdb)
+{
+ return tdb->header.hash_size;
+}