r8625: move the ldb_wrap logic into the ldb code. This logic is meant to

avoid the horrors of posix locking, but it was preventing us having an
ldb open twice with different options. Now each ldb open of the same
file shares the same underlying tdb, but uses a different ldb
structure
(This used to be commit 4e090c66dfa1d2764e4693578d3845be3b8893f6)

3 files changed, 127 insertions, 22 deletions

diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb.c b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
index 0c8d2cea3e..40cfe97c29 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_tdb.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb.c
@@ -819,16 +819,6 @@ static const struct ldb_module_ops ltdb_ops = {
 
 
 /*
-  destroy the ltdb context
-*/
-static int ltdb_destructor(void *p)
-{
-	struct ltdb_private *ltdb = p;
-	tdb_close(ltdb->tdb);
-	return 0;
-}
-
-/*
   connect to the database
 */
 int ltdb_connect(struct ldb_context *ldb, const char *url, 
@@ -837,7 +827,6 @@ int ltdb_connect(struct ldb_context *ldb, const char *url,
 	const char *path;
 	int tdb_flags, open_flags;
 	struct ltdb_private *ltdb;
-	TDB_CONTEXT *tdb;
 
 	/* parse the url */
 	if (strchr(url, ':')) {
@@ -858,24 +847,21 @@ int ltdb_connect(struct ldb_context *ldb, const char *url,
 		open_flags = O_CREAT | O_RDWR;
 	}
 
-	/* note that we use quite a large default hash size */
-	tdb = tdb_open(path, 10000, tdb_flags, open_flags, 0666);
-	if (!tdb) {
-		ldb_debug(ldb, LDB_DEBUG_ERROR, "Unable to open tdb '%s'\n", path);
-		return -1;
-	}
-
 	ltdb = talloc_zero(ldb, struct ltdb_private);
 	if (!ltdb) {
-		tdb_close(tdb);
 		ldb_oom(ldb);
 		return -1;
 	}
 
-	ltdb->tdb = tdb;
-	ltdb->sequence_number = 0;
+	/* note that we use quite a large default hash size */
+	ltdb->tdb = ltdb_wrap_open(ltdb, path, 10000, tdb_flags, open_flags, 0666);
+	if (!ltdb->tdb) {
+		ldb_debug(ldb, LDB_DEBUG_ERROR, "Unable to open tdb '%s'\n", path);
+		talloc_free(ltdb);
+		return -1;
+	}
 
-	talloc_set_destructor(ltdb, ltdb_destructor);
+	ltdb->sequence_number = 0;
 
 	ldb->modules = talloc(ldb, struct ldb_module);
 	if (!ldb->modules) {
diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb.h b/source4/lib/ldb/ldb_tdb/ldb_tdb.h
index 46c5843d60..9ee3bfb70f 100644
--- a/source4/lib/ldb/ldb_tdb/ldb_tdb.h
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb.h
@@ -105,3 +105,7 @@ int ltdb_unlock_read(struct ldb_module *module);
 int ltdb_index_del_value(struct ldb_module *module, const char *dn, 
 			 struct ldb_message_element *el, int v_idx);
 
+struct tdb_context *ltdb_wrap_open(TALLOC_CTX *mem_ctx,
+				   const char *path, int hash_size, int tdb_flags,
+				   int open_flags, mode_t mode);
+
diff --git a/source4/lib/ldb/ldb_tdb/ldb_tdb_wrap.c b/source4/lib/ldb/ldb_tdb/ldb_tdb_wrap.c
new file mode 100644
index 0000000000..f58ec7f7ff
--- /dev/null
+++ b/source4/lib/ldb/ldb_tdb/ldb_tdb_wrap.c
@@ -0,0 +1,115 @@
+/* 
+   ldb database library
+
+   Copyright (C) Andrew Tridgell  2005
+
+     ** NOTE! The following LGPL license applies to the ldb
+     ** 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 "includes.h"
+#include "ldb/include/ldb.h"
+#include "ldb/include/ldb_private.h"
+#include "ldb/ldb_tdb/ldb_tdb.h"
+
+/*
+  the purpose of this code is to work around the braindead posix locking
+  rules, to allow us to have a ldb open more than once while allowing 
+  locking to work
+*/
+
+struct ltdb_wrap {
+	struct ltdb_wrap *next, *prev;
+	struct tdb_context *tdb;
+	dev_t device;
+	ino_t inode;
+};
+
+static struct ltdb_wrap *tdb_list;
+
+/* destroy the last connection to a tdb */
+static int ltdb_wrap_destructor(void *ctx)
+{
+	struct ltdb_wrap *w = talloc_get_type(ctx, struct ltdb_wrap);
+	tdb_close(w->tdb);
+	if (w->next) {
+		w->next->prev = w->prev;
+	}
+	if (w->prev) {
+		w->prev->next = w->next;
+	}
+	if (w == tdb_list) {
+		tdb_list = w->next;
+	}
+	return 0;
+}				 
+
+/*
+  wrapped connection to a tdb database. The caller should _not_ free
+  this as it is not a talloc structure (as tdb does not use talloc
+  yet). It will auto-close when the caller frees the mem_ctx that is
+  passed to this call
+ */
+struct tdb_context *ltdb_wrap_open(TALLOC_CTX *mem_ctx,
+				   const char *path, int hash_size, int tdb_flags,
+				   int open_flags, mode_t mode)
+{
+	struct ltdb_wrap *w;
+	struct stat st;
+
+	if (stat(path, &st) == 0) {
+		for (w=tdb_list;w;w=w->next) {
+			if (st.st_dev == w->device && st.st_ino == w->inode) {
+				talloc_reference(mem_ctx, w);
+				return w->tdb;
+			}
+		}
+	}
+
+	w = talloc(mem_ctx, struct ltdb_wrap);
+	if (w == NULL) {
+		return NULL;
+	}
+
+	w->tdb = tdb_open(path, hash_size, tdb_flags, open_flags, mode);
+	if (w->tdb == NULL) {
+		talloc_free(w);
+		return NULL;
+	}
+
+	if (fstat(w->tdb->fd, &st) != 0) {
+		tdb_close(w->tdb);
+		talloc_free(w);
+		return NULL;
+	}
+
+	w->device = st.st_dev;
+	w->inode  = st.st_ino;
+
+	talloc_set_destructor(w, ltdb_wrap_destructor);
+
+	w->next = tdb_list;
+	w->prev = NULL;
+	if (tdb_list) {
+		tdb_list->prev = w;
+	}
+	tdb_list = w;
+	
+	return w->tdb;
+}
+