autofs-5.0.3 - library reload fix

From: Ian Kent <raven@themaw.net>

During a map re-read autofs needs to re-open its lookup libraries but
dependent shared libraries can't handle being unloaded and then re-loaded
by the same process. This patch preventis dependent libraries from being
unloaded during this re-open.
---

 CHANGELOG          |    1 +
 daemon/automount.c |    1 -
 daemon/lookup.c    |   21 +++++++++------------
 daemon/state.c     |    3 +++
 include/master.h   |   17 +++--------------
 lib/master.c       |   28 ++++++++++++++++++++++------
 6 files changed, 38 insertions(+), 33 deletions(-)


diff --git a/CHANGELOG b/CHANGELOG
index aec8c49..9869245 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -43,6 +43,7 @@
 - fix rootless direct multi-mount expire.
 - wait submount expire thread completion.
 - add missing uris list locking.
+- fix segv during library re-open.
  
 14/01/2008 autofs-5.0.3
 -----------------------
diff --git a/daemon/automount.c b/daemon/automount.c
index 5b6a561..d8e5f68 100644
--- a/daemon/automount.c
+++ b/daemon/automount.c
@@ -85,7 +85,6 @@ int aquire_flag_file(void);
 void release_flag_file(void);
 static int umount_all(struct autofs_point *ap, int force);
 
-extern pthread_mutex_t master_mutex;
 extern struct master *master_list;
 
 static int do_mkdir(const char *parent, const char *path, mode_t mode)
diff --git a/daemon/lookup.c b/daemon/lookup.c
index db3b636..2233ac8 100644
--- a/daemon/lookup.c
+++ b/daemon/lookup.c
@@ -267,17 +267,17 @@ static int do_read_map(struct autofs_point *ap, struct map_source *map, time_t a
 	struct lookup_mod *lookup;
 	int status;
 
-	if (!map->lookup) {
-		lookup = open_lookup(map->type, "",
-				map->format, map->argc, map->argv);
-		if (!lookup) {
-			debug(ap->logopt, "lookup module %s failed", map->type);
-			return NSS_STATUS_UNAVAIL;
-		}
-		map->lookup = lookup;
+	lookup = open_lookup(map->type, "", map->format, map->argc, map->argv);
+	if (!lookup) {
+		debug(ap->logopt, "lookup module %s failed", map->type);
+		return NSS_STATUS_UNAVAIL;
 	}
 
-	lookup = map->lookup;
+	master_source_writelock(ap->entry);
+	if (map->lookup)
+		close_lookup(map->lookup);
+	map->lookup = lookup;
+	master_source_unlock(ap->entry);
 
 	/* If we don't need to create directories then there's no use
 	 * reading the map. We just need to test that the map is valid
@@ -463,8 +463,6 @@ int lookup_nss_read_map(struct autofs_point *ap, struct map_source *source, time
 	 * point in the master map) do the nss lookup to
 	 * locate the map and read it.
 	 */
-	pthread_cleanup_push(master_source_lock_cleanup, entry);
-	master_source_readlock(entry);
 	if (source)
 		map = source;
 	else
@@ -557,7 +555,6 @@ int lookup_nss_read_map(struct autofs_point *ap, struct map_source *source, time
 
 		map = map->next;
 	}
-	pthread_cleanup_pop(1);
 
 	if (!result || at_least_one)
 		return 1;
diff --git a/daemon/state.c b/daemon/state.c
index 0042a74..1915a9f 100644
--- a/daemon/state.c
+++ b/daemon/state.c
@@ -387,9 +387,12 @@ static void *do_readmap(void *arg)
 
 	info(ap->logopt, "re-reading map for %s", ap->path);
 
+	pthread_cleanup_push(master_mutex_lock_cleanup, NULL);
+	master_mutex_lock();
 	status = lookup_nss_read_map(ap, NULL, now);
 	if (!status)
 		pthread_exit(NULL);
+	pthread_cleanup_pop(1);
 
 	if (ap->type == LKP_INDIRECT) {
 		lookup_prune_cache(ap, now);
diff --git a/include/master.h b/include/master.h
index e62c67b..6d801a9 100644
--- a/include/master.h
+++ b/include/master.h
@@ -70,6 +70,9 @@ int master_parse_entry(const char *, unsigned int, unsigned int, time_t);
 
 /* From master.c master parser utility routines */
 
+void master_mutex_lock(void);
+void master_mutex_unlock(void);
+void master_mutex_lock_cleanup(void *);
 void master_set_default_timeout(void);
 void master_set_default_ghost_mode(void);
 int master_add_autofs_point(struct master_mapent *, time_t, unsigned, unsigned, int);
@@ -108,18 +111,4 @@ extern inline unsigned int master_get_logopt(void);
 int master_list_empty(struct master *);
 int master_kill(struct master *);
 
-#define master_mutex_lock() \
-do { \
-	int status = pthread_mutex_lock(&master_mutex); \
-	if (status) \
-		fatal(status); \
-} while (0)
-
-#define master_mutex_unlock() \
-do { \
-	int status = pthread_mutex_unlock(&master_mutex); \
-	if (status) \
-		fatal(status); \
-} while (0)
-
 #endif
diff --git a/lib/master.c b/lib/master.c
index ce5b987..8bc1248 100644
--- a/lib/master.c
+++ b/lib/master.c
@@ -41,8 +41,28 @@ static struct map_source *
 __master_find_map_source(struct master_mapent *,
 			 const char *, const char *, int, const char **);
 
-pthread_mutex_t master_mutex = PTHREAD_MUTEX_INITIALIZER;
-pthread_mutex_t instance_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t master_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_mutex_t instance_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+void master_mutex_lock(void)
+{
+	int status = pthread_mutex_lock(&master_mutex);
+	if (status)
+		fatal(status);
+}
+
+void master_mutex_unlock(void)
+{
+	int status = pthread_mutex_unlock(&master_mutex);
+	if (status)
+		fatal(status);
+}
+
+void master_mutex_lock_cleanup(void *arg)
+{
+	master_mutex_unlock();
+	return;
+}
 
 int master_add_autofs_point(struct master_mapent *entry,
 		time_t timeout, unsigned logopt, unsigned ghost, int submount) 
@@ -1109,10 +1129,6 @@ int master_mount_mounts(struct master *master, time_t age, int readall)
 			continue;
 		}
 
-		master_source_writelock(ap->entry);
-		lookup_close_lookup(ap);
-		master_source_unlock(ap->entry);
-
 		cache_readlock(nc);
 		ne = cache_lookup_distinct(nc, this->path);
 		if (ne && this->age > ne->age) {