autofs-5.1.8 - serialise lookup module open and reinit

From: Ian Kent <raven@themaw.net>

Add a map source lock to serialise map setting and use of module

structure fields such as the context.

Signed-off-by: Ian Kent <raven@themaw.net>

---

 CHANGELOG           |    1 +

 daemon/lookup.c     |   35 +++++++++++++++++++++--------------

 daemon/master.c     |   43 +++++++++++++++++++++++++++++++++++++++++++

 include/master.h    |    5 +++++

 modules/parse_amd.c |   26 +++++++++++++++-----------

 5 files changed, 85 insertions(+), 25 deletions(-)

--- autofs-5.1.7.orig/CHANGELOG

+++ autofs-5.1.7/CHANGELOG

@@ -105,6 +105,7 @@

 - fix invalid tsv access.

 - fix missing unlock in sasl_do_kinit_ext_cc().

 - fix parse module instance mutex naming.

+- serialise lookup module open and reinit.

 25/01/2021 autofs-5.1.7

 - make bind mounts propagation slave by default.

--- autofs-5.1.7.orig/daemon/lookup.c

+++ autofs-5.1.7/daemon/lookup.c

@@ -318,28 +318,27 @@ static int do_read_map(struct autofs_poi

 	struct lookup_mod *lookup;

 	int status;

-	lookup = NULL;

-	master_source_writelock(ap->entry);

+	pthread_cleanup_push(map_module_lock_cleanup, map);

+	map_module_writelock(map);

 	if (!map->lookup) {

 		status = open_lookup(map->type, "", map->format,

 				     map->argc, map->argv, &lookup);

-		if (status != NSS_STATUS_SUCCESS) {

-			master_source_unlock(ap->entry);

+		if (status == NSS_STATUS_SUCCESS)

+			map->lookup = lookup;

+		else

 			debug(ap->logopt,

 			      "lookup module %s open failed", map->type);

-			return status;

-		}

-		map->lookup = lookup;

 	} else {

-		lookup = map->lookup;

-		status = lookup->lookup_reinit(map->format,

-					       map->argc, map->argv,

-					       &lookup->context);

+		status = map->lookup->lookup_reinit(map->format,

+						    map->argc, map->argv,

+						    &map->lookup->context);

 		if (status)

 			warn(ap->logopt,

 			     "lookup module %s reinit failed", map->type);

 	}

-	master_source_unlock(ap->entry);

+	pthread_cleanup_pop(1);

+	if (status != NSS_STATUS_SUCCESS)

+		return status;

 	if (!map->stale)

 		return NSS_STATUS_SUCCESS;

@@ -347,7 +346,11 @@ static int do_read_map(struct autofs_poi

 	master_source_current_wait(ap->entry);

 	ap->entry->current = map;

+	pthread_cleanup_push(map_module_lock_cleanup, map);

+	map_module_readlock(map);

+	lookup = map->lookup;

 	status = lookup->lookup_read_map(ap, age, lookup->context);

+	pthread_cleanup_pop(1);

 	if (status != NSS_STATUS_SUCCESS)

 		map->stale = 0;

@@ -804,23 +807,27 @@ int do_lookup_mount(struct autofs_point

 	struct lookup_mod *lookup;

 	int status;

+	map_module_writelock(map);

 	if (!map->lookup) {

 		status = open_lookup(map->type, "",

 				     map->format, map->argc, map->argv, &lookup);

 		if (status != NSS_STATUS_SUCCESS) {

+			map_module_unlock(map);

 			debug(ap->logopt,

 			      "lookup module %s open failed", map->type);

 			return status;

 		}

 		map->lookup = lookup;

 	}

-

-	lookup = map->lookup;

+	map_module_unlock(map);

 	master_source_current_wait(ap->entry);

 	ap->entry->current = map;

+	map_module_readlock(map);

+	lookup = map->lookup;

 	status = lookup->lookup_mount(ap, name, name_len, lookup->context);

+	map_module_unlock(map);

 	return status;

 }

--- autofs-5.1.7.orig/daemon/master.c

+++ autofs-5.1.7/daemon/master.c

@@ -65,6 +65,34 @@ void master_mutex_lock_cleanup(void *arg

 	return;

 }

+void map_module_writelock(struct map_source *map)

+{

+	int status = pthread_rwlock_wrlock(&map->module_lock);

+	if (status)

+		fatal(status);

+}

+

+void map_module_readlock(struct map_source *map)

+{

+	int status = pthread_rwlock_rdlock(&map->module_lock);

+	if (status)

+		fatal(status);

+}

+

+void map_module_unlock(struct map_source *map)

+{

+	int status = pthread_rwlock_unlock(&map->module_lock);

+	if (status)

+		fatal(status);

+}

+

+void map_module_lock_cleanup(void *arg)

+{

+	struct map_source *map = (struct map_source *) arg;

+

+	map_module_unlock(map);

+}

+

 int master_add_autofs_point(struct master_mapent *entry, unsigned logopt,

 			    unsigned nobind, unsigned ghost, int submount)

 {

@@ -155,6 +183,7 @@ master_add_map_source(struct master_mape

 	struct map_source *source;

 	char *ntype, *nformat;

 	const char **tmpargv;

+	int status;

 	source = malloc(sizeof(struct map_source));

 	if (!source)

@@ -241,6 +270,10 @@ master_add_map_source(struct master_mape

 	master_source_unlock(entry);

+	status = pthread_rwlock_init(&source->module_lock, NULL);

+	if (status)

+		fatal(status);

+

 	return source;

 }

@@ -330,6 +363,8 @@ master_get_map_source(struct master_mape

 static void __master_free_map_source(struct map_source *source, unsigned int free_cache)

 {

+	int status;

+

 	/* instance map sources are not ref counted */

 	if (source->ref && --source->ref)

 		return;

@@ -365,6 +400,10 @@ static void __master_free_map_source(str

 		}

 	}

+	status = pthread_rwlock_destroy(&source->module_lock);

+	if (status)

+		fatal(status);

+

 	free(source);

 	return;

@@ -496,6 +535,10 @@ master_add_source_instance(struct map_so

 	if (status)

 		fatal(status);

+	status = pthread_rwlock_init(&new->module_lock, NULL);

+	if (status)

+		fatal(status);

+

 	return new;

 }

--- autofs-5.1.7.orig/include/master.h

+++ autofs-5.1.7/include/master.h

@@ -35,6 +35,7 @@ struct map_source {

 	unsigned int stale;

 	unsigned int recurse;

 	unsigned int depth;

+	pthread_rwlock_t module_lock;

 	struct lookup_mod *lookup;

 	int argc;

 	const char **argv;

@@ -126,5 +127,9 @@ int __master_list_empty(struct master *)

 int master_list_empty(struct master *);

 int master_done(struct master *);

 int master_kill(struct master *);

+void map_module_writelock(struct map_source *map);

+void map_module_readlock(struct map_source *map);

+void map_module_unlock(struct map_source *map);

+void map_module_lock_cleanup(void *arg);

 #endif

--- autofs-5.1.7.orig/modules/parse_amd.c

+++ autofs-5.1.7/modules/parse_amd.c

@@ -1358,14 +1358,6 @@ static int do_host_mount(struct autofs_p

 		argc = 1;

 	}

-	parse_instance_mutex_lock();

-	status = open_lookup("hosts", MODPREFIX, NULL, argc, pargv, &lookup);

-	if (status != NSS_STATUS_SUCCESS) {

-		debug(ap->logopt, "open lookup module hosts failed");

-		parse_instance_mutex_unlock();

-		goto out;

-	}

-

 	instance = master_find_source_instance(source,

 					 "hosts", "sun", argc, pargv);

 	if (!instance) {

@@ -1374,13 +1366,22 @@ static int do_host_mount(struct autofs_p

 		if (!instance) {

 			error(ap->logopt, MODPREFIX

 			     "failed to create source instance for hosts map");

-			parse_instance_mutex_unlock();

 			close_lookup(lookup);

 			goto out;

 		}

 	}

-	instance->lookup = lookup;

-	parse_instance_mutex_unlock();

+

+	map_module_writelock(instance);

+	if (!instance->lookup) {

+		status = open_lookup("hosts", MODPREFIX, NULL, argc, pargv, &lookup);

+		if (status != NSS_STATUS_SUCCESS) {

+			map_module_unlock(instance);

+			debug(ap->logopt, "open lookup module hosts failed");

+			goto out;

+		}

+		instance->lookup = lookup;

+	}

+	map_module_unlock(instance);

 	cache_writelock(source->mc);

 	me = cache_lookup_distinct(source->mc, name);

@@ -1391,8 +1392,11 @@ static int do_host_mount(struct autofs_p

 	master_source_current_wait(ap->entry);

 	ap->entry->current = source;

+	map_module_readlock(instance);

+	lookup = instance->lookup;

 	ret = lookup->lookup_mount(ap, entry->rhost,

 				   strlen(entry->rhost), lookup->context);

+	map_module_unlock(instance);

 	if (!strcmp(name, entry->rhost))

 		goto out;