1 files changed, 78 insertions, 0 deletions
diff --git a/source3/lib/server_mutex.c b/source3/lib/server_mutex.c
new file mode 100644
index 0000000000..43c0de1975
--- /dev/null
+++ b/source3/lib/server_mutex.c
@@ -0,0 +1,78 @@
+/* 
+   Unix SMB/CIFS implementation.
+   Authenticate against a remote domain
+   Copyright (C) Andrew Tridgell 1992-2002
+   Copyright (C) Andrew Bartlett 2002
+   
+   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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+
+/* For reasons known only to MS, many of their NT/Win2k versions
+   need serialised access only.  Two connections at the same time
+   may (in certain situations) cause connections to be reset,
+   or access to be denied.
+
+   This locking allows smbd's mutlithread architecture to look
+   like the single-connection that NT makes. */
+
+struct named_mutex {
+	struct tdb_wrap *tdb;
+	char *name;
+};
+
+static int unlock_named_mutex(struct named_mutex *mutex)
+{
+	tdb_unlock_bystring(mutex->tdb->tdb, mutex->name);
+	return 0;
+}
+
+struct named_mutex *grab_named_mutex(TALLOC_CTX *mem_ctx, const char *name,
+				     int timeout)
+{
+	struct named_mutex *result;
+
+	result = talloc(mem_ctx, struct named_mutex);
+	if (result == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		return NULL;
+	}
+
+	result->name = talloc_strdup(result, name);
+	if (result->name == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	result->tdb = tdb_wrap_open(result, lock_path("mutex.tdb"), 0,
+				    TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
+	if (result->tdb == NULL) {
+		DEBUG(1, ("Could not open mutex.tdb: %s\n",
+			  strerror(errno)));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	if (tdb_lock_bystring_with_timeout(result->tdb->tdb, name,
+					   timeout) == -1) {
+		DEBUG(1, ("Could not get the lock for %s\n", name));
+		TALLOC_FREE(result);
+		return NULL;
+	}
+
+	talloc_set_destructor(result, unlock_named_mutex);
+	return result;
+}