r3005: added talloc wrappers around tdb_open() and ldb_connect(), so that the

caller doesn't have to worry about the constraint of only opening a
database a single time in a process. These wrappers will ensure that
only a single open is done, and will auto-close when the last instance
is gone.

When you are finished with a database pointer, use talloc_free() to
close it.

note that this code does not take account of the threads process
model, and does not yet take account of symlinks or hard links to tdb
files.
(This used to be commit 04e1171996612ddb15f84134cadded68f0d173b2)

6 files changed, 208 insertions, 81 deletions

diff --git a/source4/lib/basic.mk b/source4/lib/basic.mk
index addef77a20..93309ce68b 100644
--- a/source4/lib/basic.mk
+++ b/source4/lib/basic.mk
@@ -50,7 +50,7 @@ ADD_OBJ_FILES = \
 		lib/crypto/md5.o \
 		lib/crypto/hmacmd5.o \
 		lib/crypto/md4.o \
-		lib/tdb_helper.o \
+		lib/db_wrap.o \
 		lib/server_mutex.o 
 REQUIRED_SUBSYSTEMS = \
 		LIBTDB CHARSET
diff --git a/source4/lib/db_wrap.c b/source4/lib/db_wrap.c
new file mode 100644
index 0000000000..251741c5b0
--- /dev/null
+++ b/source4/lib/db_wrap.c
@@ -0,0 +1,170 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   database wrap functions
+
+   Copyright (C) Andrew Tridgell 2004
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program 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 General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/*
+  the stupidity of the unix fcntl locking design forces us to never
+  allow a database file to be opened twice in the same process. These
+  wrappers provide convenient access to a tdb or ldb, taking advantage
+  of talloc destructors to ensure that only a single open is done
+*/
+
+#include "includes.h"
+
+static struct ldb_wrap *ldb_list;
+static struct tdb_wrap *tdb_list;
+
+/*
+  this is used to catch debug messages from ldb
+*/
+static void ldb_wrap_debug(void *context, enum ldb_debug_level level, 
+			   const char *fmt, va_list ap)  PRINTF_ATTRIBUTE(3,0);
+
+static void ldb_wrap_debug(void *context, enum ldb_debug_level level, 
+			   const char *fmt, va_list ap)
+{
+	char *s = NULL;
+	if (DEBUGLEVEL < 4 && level > LDB_DEBUG_WARNING) {
+		return;
+	}
+	vasprintf(&s, fmt, ap);
+	if (!s) return;
+	DEBUG(level, ("ldb: %s\n", s));
+	free(s);
+}
+
+
+/* destroy the last connection to a ldb */
+static int ldb_wrap_destructor(void *ctx)
+{
+	struct ldb_wrap *w = ctx;
+	ldb_close(w->ldb);
+	DLIST_REMOVE(ldb_list, w);
+	return 0;
+}				 
+
+/*
+  wrapped connection to a ldb database
+  to close just talloc_free() the ldb_wrap pointer
+ */
+struct ldb_wrap *ldb_wrap_connect(TALLOC_CTX *mem_ctx,
+				  const char *url,
+				  unsigned int flags,
+				  const char *options[])
+{
+	struct ldb_wrap *w;
+
+	for (w=ldb_list;w;w=w->next) {
+		if (strcmp(url, w->url) == 0) {
+			return talloc_reference(mem_ctx, w);
+		}
+	}
+
+	w = talloc_p(mem_ctx, struct ldb_wrap);
+	if (w == NULL) {
+		return NULL;
+	}
+
+	w->url = talloc_strdup(w, url);
+
+	w->ldb = ldb_connect(url, flags, options);
+	if (w->ldb == NULL) {
+		talloc_free(w);
+		return NULL;
+	}
+
+	talloc_set_destructor(w, ldb_wrap_destructor);
+	ldb_set_debug(w->ldb, ldb_wrap_debug, NULL);
+
+	DLIST_ADD(ldb_list, w);
+
+	return w;
+}
+
+
+/*
+ Log tdb messages via DEBUG().
+*/
+static void tdb_wrap_log(TDB_CONTEXT *tdb, int level, 
+			 const char *format, ...) PRINTF_ATTRIBUTE(3,4);
+
+static void tdb_wrap_log(TDB_CONTEXT *tdb, int level, 
+			 const char *format, ...)
+{
+	va_list ap;
+	char *ptr = NULL;
+
+	va_start(ap, format);
+	vasprintf(&ptr, format, ap);
+	va_end(ap);
+	
+	if (ptr != NULL) {
+		DEBUG(level, ("tdb(%s): %s", tdb->name ? tdb->name : "unnamed", ptr));
+		free(ptr);
+	}
+}
+
+
+/* destroy the last connection to a tdb */
+static int tdb_wrap_destructor(void *ctx)
+{
+	struct tdb_wrap *w = ctx;
+	tdb_close(w->tdb);
+	DLIST_REMOVE(tdb_list, w);
+	return 0;
+}				 
+
+/*
+  wrapped connection to a tdb database
+  to close just talloc_free() the tdb_wrap pointer
+ */
+struct tdb_wrap *tdb_wrap_open(TALLOC_CTX *mem_ctx,
+			       const char *name, int hash_size, int tdb_flags,
+			       int open_flags, mode_t mode)
+{
+	struct tdb_wrap *w;
+
+	for (w=tdb_list;w;w=w->next) {
+		if (strcmp(name, w->name) == 0) {
+			return talloc_reference(mem_ctx, w);
+		}
+	}
+
+	w = talloc_p(mem_ctx, struct tdb_wrap);
+	if (w == NULL) {
+		return NULL;
+	}
+
+	w->name = talloc_strdup(w, name);
+
+	w->tdb = tdb_open_ex(name, hash_size, tdb_flags, 
+			     open_flags, mode, tdb_wrap_log, NULL);
+	if (w->tdb == NULL) {
+		talloc_free(w);
+		return NULL;
+	}
+
+	talloc_set_destructor(w, tdb_wrap_destructor);
+
+	DLIST_ADD(tdb_list, w);
+
+	return w;
+}
diff --git a/source4/lib/gencache.c b/source4/lib/gencache.c
index 1a66d8dc3d..a176dc5ae8 100644
--- a/source4/lib/gencache.c
+++ b/source4/lib/gencache.c
@@ -29,7 +29,7 @@
 #define TIMEOUT_LEN 12
 #define CACHE_DATA_FMT	"%12u/%s"
 
-static TDB_CONTEXT *cache;
+static struct tdb_wrap *cache;
 
 /**
  * @file gencache.c
@@ -62,8 +62,8 @@ BOOL gencache_init(void)
 		return False;
 	}
 
-	cache = tdb_open_log(cache_fname, 0, TDB_DEFAULT,
-	                     O_RDWR|O_CREAT, 0644);
+	cache = tdb_wrap_open(NULL, cache_fname, 0, TDB_DEFAULT,
+			      O_RDWR|O_CREAT, 0644);
 
 	SAFE_FREE(cache_fname);
 	if (!cache) {
@@ -83,10 +83,10 @@ BOOL gencache_init(void)
  
 BOOL gencache_shutdown(void)
 {
-	/* tdb_close routine returns -1 on error */
 	if (!cache) return False;
 	DEBUG(5, ("Closing cache file\n"));
-	return tdb_close(cache) != -1;
+	talloc_free(cache);
+	return True;
 }
 
 
@@ -125,7 +125,7 @@ BOOL gencache_set(const char *keystr, const char *value, time_t timeout)
 	           = %s (%d seconds %s)\n", keybuf.dptr, value, ctime(&timeout),
 	           (int)(timeout - time(NULL)), timeout > time(NULL) ? "ahead" : "in the past"));
 		
-	ret = tdb_store(cache, keybuf, databuf, 0);
+	ret = tdb_store(cache->tdb, keybuf, databuf, 0);
 	SAFE_FREE(valstr);
 	SAFE_FREE(keybuf.dptr);
 	SAFE_FREE(databuf.dptr);
@@ -178,7 +178,7 @@ BOOL gencache_set_only(const char *keystr, const char *valstr, time_t timeout)
 	              timeout > time(NULL) ? "ahead" : "in the past"));
 
 		
-	ret = tdb_store(cache, keybuf, databuf, TDB_REPLACE);
+	ret = tdb_store(cache->tdb, keybuf, databuf, TDB_REPLACE);
 
 	SAFE_FREE(datastr);
 	SAFE_FREE(old_valstr);
@@ -211,7 +211,7 @@ BOOL gencache_del(const char *keystr)
 	keybuf.dptr = strdup(keystr);
 	keybuf.dsize = strlen(keystr)+1;
 	DEBUG(10, ("Deleting cache entry (key = %s)\n", keystr));
-	ret = tdb_delete(cache, keybuf);
+	ret = tdb_delete(cache->tdb, keybuf);
 	
 	SAFE_FREE(keybuf.dptr);
 	return ret == 0;
@@ -243,7 +243,7 @@ BOOL gencache_get(const char *keystr, char **valstr, time_t *timeout)
 	
 	keybuf.dptr = strdup(keystr);
 	keybuf.dsize = strlen(keystr)+1;
-	databuf = tdb_fetch(cache, keybuf);
+	databuf = tdb_fetch(cache->tdb, keybuf);
 	SAFE_FREE(keybuf.dptr);
 	
 	if (databuf.dptr && databuf.dsize > TIMEOUT_LEN) {
@@ -317,7 +317,7 @@ void gencache_iterate(void (*fn)(const char* key, const char *value, time_t time
 	if (!gencache_init()) return;
 
 	DEBUG(5, ("Searching cache keys with pattern %s\n", keystr_pattern));
-	node = tdb_search_keys(cache, keystr_pattern);
+	node = tdb_search_keys(cache->tdb, keystr_pattern);
 	first_node = node;
 	
 	while (node) {
@@ -328,7 +328,7 @@ void gencache_iterate(void (*fn)(const char* key, const char *value, time_t time
 		 * We don't use gencache_get function, because we need to iterate through
 		 * all of the entries. Validity verification is up to fn routine.
 		 */
-		databuf = tdb_fetch(cache, node->node_key);
+		databuf = tdb_fetch(cache->tdb, node->node_key);
 		if (!databuf.dptr || databuf.dsize <= TIMEOUT_LEN) {
 			SAFE_FREE(databuf.dptr);
 			SAFE_FREE(keystr);
@@ -360,7 +360,7 @@ void gencache_iterate(void (*fn)(const char* key, const char *value, time_t time
 
 int gencache_lock_entry( const char *key )
 {
-	return tdb_lock_bystring(cache, key, 0);
+	return tdb_lock_bystring(cache->tdb, key, 0);
 }
 
 /********************************************************************
@@ -369,8 +369,7 @@ int gencache_lock_entry( const char *key )
 
 void gencache_unlock_entry( const char *key )
 {
-	tdb_unlock_bystring(cache, key);
-	return;
+	tdb_unlock_bystring(cache->tdb, key);
 }
 
 
diff --git a/source4/lib/messages.c b/source4/lib/messages.c
index b4de7c0145..64dc2f510a 100644
--- a/source4/lib/messages.c
+++ b/source4/lib/messages.c
@@ -48,7 +48,7 @@
 #include "includes.h"
 
 /* the locking database handle */
-static TDB_CONTEXT *tdb;
+static struct tdb_wrap *tdb;
 static int received_signal;
 
 /* change the message version with any incompatible changes in the protocol */
@@ -105,9 +105,9 @@ BOOL message_init(void)
 		DEBUG(0,("ERROR: No memory to initialise messages database\n"));
 		return False;
 	}
-	tdb = tdb_open_log(lock_path(mem_ctx, "messages.tdb"), 
-		       0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT, 
-		       O_RDWR|O_CREAT,0600);
+	tdb = tdb_wrap_open(NULL, lock_path(mem_ctx, "messages.tdb"), 
+			    0, TDB_CLEAR_IF_FIRST|TDB_DEFAULT, 
+			    O_RDWR|O_CREAT,0600);
 	talloc_destroy(mem_ctx);
 
 	if (!tdb) {
@@ -155,7 +155,7 @@ static BOOL message_notify(pid_t pid)
 	if (kill(pid, SIGUSR1) == -1) {
 		if (errno == ESRCH) {
 			DEBUG(2,("pid %d doesn't exist - deleting messages record\n", (int)pid));
-			tdb_delete(tdb, message_key_pid(pid));
+			tdb_delete(tdb->tdb, message_key_pid(pid));
 		} else {
 			DEBUG(2,("message to process %d failed - %s\n", (int)pid, strerror(errno)));
 		}
@@ -209,18 +209,18 @@ static BOOL message_send_pid_internal(pid_t pid, int msg_type, const void *buf,
 
 		/* lock the record for the destination */
 		if (timeout) {
-			if (tdb_chainlock_with_timeout(tdb, kbuf, timeout) == -1) {
+			if (tdb_chainlock_with_timeout(tdb->tdb, kbuf, timeout) == -1) {
 				DEBUG(0,("message_send_pid_internal: failed to get chainlock with timeout %ul.\n", timeout));
 				return False;
 			}
 		} else {
-			if (tdb_chainlock(tdb, kbuf) == -1) {
+			if (tdb_chainlock(tdb->tdb, kbuf) == -1) {
 				DEBUG(0,("message_send_pid_internal: failed to get chainlock.\n"));
 				return False;
 			}
 		}	
-		tdb_append(tdb, kbuf, dbuf);
-		tdb_chainunlock(tdb, kbuf);
+		tdb_append(tdb->tdb, kbuf, dbuf);
+		tdb_chainunlock(tdb->tdb, kbuf);
 
 		SAFE_FREE(dbuf.dptr);
 		errno = 0;                    /* paranoia */
@@ -229,24 +229,24 @@ static BOOL message_send_pid_internal(pid_t pid, int msg_type, const void *buf,
 
 	/* lock the record for the destination */
 	if (timeout) {
-		if (tdb_chainlock_with_timeout(tdb, kbuf, timeout) == -1) {
+		if (tdb_chainlock_with_timeout(tdb->tdb, kbuf, timeout) == -1) {
 			DEBUG(0,("message_send_pid_internal: failed to get chainlock with timeout %ul.\n", timeout));
 			return False;
 		}
 	} else {
-		if (tdb_chainlock(tdb, kbuf) == -1) {
+		if (tdb_chainlock(tdb->tdb, kbuf) == -1) {
 			DEBUG(0,("message_send_pid_internal: failed to get chainlock.\n"));
 			return False;
 		}
 	}	
 
-	old_dbuf = tdb_fetch(tdb, kbuf);
+	old_dbuf = tdb_fetch(tdb->tdb, kbuf);
 
 	if (!old_dbuf.dptr) {
 		/* its a new record */
 
-		tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
-		tdb_chainunlock(tdb, kbuf);
+		tdb_store(tdb->tdb, kbuf, dbuf, TDB_REPLACE);
+		tdb_chainunlock(tdb->tdb, kbuf);
 
 		SAFE_FREE(dbuf.dptr);
 		errno = 0;                    /* paranoia */
@@ -264,7 +264,7 @@ static BOOL message_send_pid_internal(pid_t pid, int msg_type, const void *buf,
 
 		if (!memcmp(ptr, &rec, sizeof(rec))) {
 			if (!len || (len && !memcmp( ptr + sizeof(rec), buf, len))) {
-				tdb_chainunlock(tdb, kbuf);
+				tdb_chainunlock(tdb->tdb, kbuf);
 				DEBUG(10,("message_send_pid_internal: discarding duplicate message.\n"));
 				SAFE_FREE(dbuf.dptr);
 				SAFE_FREE(old_dbuf.dptr);
@@ -277,8 +277,8 @@ static BOOL message_send_pid_internal(pid_t pid, int msg_type, const void *buf,
 
 	/* we're adding to an existing entry */
 
-	tdb_append(tdb, kbuf, dbuf);
-	tdb_chainunlock(tdb, kbuf);
+	tdb_append(tdb->tdb, kbuf, dbuf);
+	tdb_chainunlock(tdb->tdb, kbuf);
 
 	SAFE_FREE(old_dbuf.dptr);
 	SAFE_FREE(dbuf.dptr);
@@ -323,14 +323,14 @@ static BOOL retrieve_all_messages(char **msgs_buf, size_t *total_len)
 
 	kbuf = message_key_pid(getpid());
 
-	tdb_chainlock(tdb, kbuf);
-	dbuf = tdb_fetch(tdb, kbuf);
+	tdb_chainlock(tdb->tdb, kbuf);
+	dbuf = tdb_fetch(tdb->tdb, kbuf);
 	/*
 	 * Replace with an empty record to keep the allocated
 	 * space in the tdb.
 	 */
-	tdb_store(tdb, kbuf, null_dbuf, TDB_REPLACE);
-	tdb_chainunlock(tdb, kbuf);
+	tdb_store(tdb->tdb, kbuf, null_dbuf, TDB_REPLACE);
+	tdb_chainunlock(tdb->tdb, kbuf);
 
 	if (dbuf.dptr == NULL || dbuf.dsize == 0) {
 		SAFE_FREE(dbuf.dptr);
diff --git a/source4/lib/tdb/config.mk b/source4/lib/tdb/config.mk
index fdde6e7b4f..dba0d3e1d4 100644
--- a/source4/lib/tdb/config.mk
+++ b/source4/lib/tdb/config.mk
@@ -28,7 +28,7 @@ REQUIRED_SUBSYSTEMS = \
 OBJ_FILES= \
 		lib/tdb/tools/tdbtest.o
 REQUIRED_SUBSYSTEMS = \
-		LIBBASIC CONFIG LIBCMDLINE LIBTDB
+		LIBTDB
 REQUIRED_LIBRARIES = GDBM
 # End BINARY tdbtest
 ################################################
@@ -49,7 +49,7 @@ REQUIRED_SUBSYSTEMS = \
 OBJ_FILES= \
 		lib/tdb/tools/tdbtorture.o
 REQUIRED_SUBSYSTEMS = \
-		LIBBASIC CONFIG LIBCMDLINE LIBTDB
+		LIBTDB
 # End BINARY tdbtorture
 ################################################
 
@@ -59,7 +59,7 @@ REQUIRED_SUBSYSTEMS = \
 OBJ_FILES= \
 		lib/tdb/tools/tdbdump.o
 REQUIRED_SUBSYSTEMS = \
-		LIBBASIC CONFIG LIBCMDLINE LIBTDB
+		LIBTDB
 # End BINARY tdbdump
 ################################################
 
diff --git a/source4/lib/tdb_helper.c b/source4/lib/tdb_helper.c
index 2698e3cc71..e29a8a7211 100644
--- a/source4/lib/tdb_helper.c
+++ b/source4/lib/tdb_helper.c
@@ -25,45 +25,3 @@
    dealing with a tdb database a little less cumbersome in Samba */
 
 
-/****************************************************************************
- Log tdb messages via DEBUG().
-****************************************************************************/
-
-static void tdb_log(TDB_CONTEXT *tdb, int level, const char *format, ...) PRINTF_ATTRIBUTE(3,4);
-
-static void tdb_log(TDB_CONTEXT *tdb, int level, const char *format, ...)
-{
-	va_list ap;
-	char *ptr = NULL;
-
-	va_start(ap, format);
-	vasprintf(&ptr, format, ap);
-	va_end(ap);
-	
-	if (!ptr || !*ptr)
-		return;
-
-	DEBUG(level, ("tdb(%s): %s", tdb->name ? tdb->name : "unnamed", ptr));
-	SAFE_FREE(ptr);
-}
-
-/****************************************************************************
- Like tdb_open() but also setup a logging function that redirects to
- the samba DEBUG() system.
-****************************************************************************/
-
-TDB_CONTEXT *tdb_open_log(const char *name, int hash_size, int tdb_flags,
-			  int open_flags, mode_t mode)
-{
-	TDB_CONTEXT *tdb;
-
-	if (!lp_use_mmap())
-		tdb_flags |= TDB_NOMMAP;
-
-	tdb = tdb_open_ex(name, hash_size, tdb_flags, 
-				    open_flags, mode, tdb_log, NULL);
-	if (!tdb)
-		return NULL;
-
-	return tdb;
-}