diff --git a/main/loader.c b/main/loader.c
index 49151ccb9e69d3d205d166d4d3a1ab9fe013825f..e0733651f56138fc3b896354ba9ac1e3acc94a90 100644
--- a/main/loader.c
+++ b/main/loader.c
@@ -167,38 +167,51 @@ static int do_full_reload = 0;
static AST_DLLIST_HEAD_STATIC(reload_queue, reload_queue_item);
-/* when dynamic modules are being loaded, ast_module_register() will
- need to know what filename the module was loaded from while it
- is being registered
-*/
+/*!
+ * \internal
+ *
+ * This variable is set by load_dynamic_module so ast_module_register
+ * can know what pointer is being registered.
+ *
+ * This is protected by the module_list lock.
+ */
static struct ast_module *resource_being_loaded;
-/* XXX: should we check for duplicate resource names here? */
-
+/*!
+ * \internal
+ * \brief Used by AST_MODULE_INFO to register with the module loader.
+ *
+ * This function is automatically called when each module is opened.
+ * It must never be used from outside AST_MODULE_INFO.
+ */
void ast_module_register(const struct ast_module_info *info)
{
- struct ast_module *mod = resource_being_loaded;
+ struct ast_module *mod;
+
+ /*
+ * This lock protects resource_being_loaded as well as the module
+ * list. Normally we already have a lock on module_list when we
+ * begin the load but locking again from here prevents corruption
+ * if an asterisk module is dlopen'ed from outside the module loader.
+ */
+ AST_DLLIST_LOCK(&module_list);
+ mod = resource_being_loaded;
+ if (!mod) {
+ AST_DLLIST_UNLOCK(&module_list);
+ return;
+ }
ast_debug(5, "Registering module %s\n", info->name);
+ /* This tells load_dynamic_module that we're registered. */
+ resource_being_loaded = NULL;
+
mod->info = info;
if (ast_opt_ref_debug) {
mod->ref_debug = ao2_t_alloc(0, NULL, info->name);
}
AST_LIST_HEAD_INIT(&mod->users);
- /* during startup, before the loader has been initialized,
- there are no threads, so there is no need to take the lock
- on this list to manipulate it. it is also possible that it
- might be unsafe to use the list lock at that point... so
- let's avoid it altogether
- */
- AST_DLLIST_LOCK(&module_list);
- /* it is paramount that the new entry be placed at the tail of
- the list, otherwise the code that uses dlopen() to load
- dynamic modules won't be able to find out if the module it
- just opened was registered or failed to load
- */
AST_DLLIST_INSERT_TAIL(&module_list, mod, entry);
AST_DLLIST_UNLOCK(&module_list);
@@ -206,6 +219,13 @@ void ast_module_register(const struct ast_module_info *info)
*((struct ast_module **) &(info->self)) = mod;
}
+static void module_destroy(struct ast_module *mod)
+{
+ AST_LIST_HEAD_DESTROY(&mod->users);
+ ao2_cleanup(mod->ref_debug);
+ ast_free(mod);
+}
+
void ast_module_unregister(const struct ast_module_info *info)
{
struct ast_module *mod = NULL;
@@ -226,9 +246,7 @@ void ast_module_unregister(const struct ast_module_info *info)
if (mod) {
ast_debug(5, "Unregistering module %s\n", info->name);
- AST_LIST_HEAD_DESTROY(&mod->users);
- ao2_cleanup(mod->ref_debug);
- ast_free(mod);
+ module_destroy(mod);
}
}
@@ -511,6 +529,8 @@ static struct ast_module *load_dynamic_module(const char *resource_in, unsigned
int space; /* room needed for the descriptor */
int missing_so = 0;
+ ast_assert(!resource_being_loaded);
+
space = sizeof(*resource_being_loaded) + strlen(resource_in) + 1;
if (strcasecmp(resource_in + strlen(resource_in) - 3, ".so")) {
missing_so = 1;
@@ -523,34 +543,23 @@ static struct ast_module *load_dynamic_module(const char *resource_in, unsigned
any symbols, and don't export any symbols. this will allow us to peek into
the module's info block (if available) to see what flags it has set */
- resource_being_loaded = ast_calloc(1, space);
+ mod = resource_being_loaded = ast_calloc(1, space);
if (!resource_being_loaded)
return NULL;
strcpy(resource_being_loaded->resource, resource_in);
if (missing_so)
strcat(resource_being_loaded->resource, ".so");
- if (!(lib = dlopen(fn, RTLD_LAZY | RTLD_GLOBAL))) {
- if (!suppress_logging) {
+ lib = dlopen(fn, RTLD_LAZY | RTLD_GLOBAL);
+ if (resource_being_loaded) {
+ resource_being_loaded = NULL;
+ if (lib) {
+ ast_log(LOG_ERROR, "Module '%s' did not register itself during load\n", resource_in);
+ logged_dlclose(resource_in, lib);
+ } else if (!suppress_logging) {
ast_log(LOG_WARNING, "Error loading module '%s': %s\n", resource_in, dlerror());
}
- ast_free(resource_being_loaded);
- return NULL;
- }
-
- /* the dlopen() succeeded, let's find out if the module
- registered itself */
- /* note that this will only work properly as long as
- ast_module_register() (which is called by the module's
- constructor) places the new module at the tail of the
- module_list
- */
- if (resource_being_loaded != (mod = AST_DLLIST_LAST(&module_list))) {
- ast_log(LOG_WARNING, "Module '%s' did not register itself during load\n", resource_in);
- /* no, it did not, so close it and return */
- logged_dlclose(resource_in, lib);
- /* note that the module's destructor will call ast_module_unregister(),
- which will free the structure we allocated in resource_being_loaded */
+ ast_free(mod);
return NULL;
}
@@ -564,19 +573,20 @@ static struct ast_module *load_dynamic_module(const char *resource_in, unsigned
}
logged_dlclose(resource_in, lib);
- resource_being_loaded = NULL;
/* start the load process again */
- resource_being_loaded = ast_calloc(1, space);
+ mod = resource_being_loaded = ast_calloc(1, space);
if (!resource_being_loaded)
return NULL;
strcpy(resource_being_loaded->resource, resource_in);
if (missing_so)
strcat(resource_being_loaded->resource, ".so");
- if (!(lib = dlopen(fn, wants_global ? RTLD_LAZY | RTLD_GLOBAL : RTLD_NOW | RTLD_LOCAL))) {
+ lib = dlopen(fn, wants_global ? RTLD_LAZY | RTLD_GLOBAL : RTLD_NOW | RTLD_LOCAL);
+ resource_being_loaded = NULL;
+ if (!lib) {
ast_log(LOG_WARNING, "Error loading module '%s': %s\n", resource_in, dlerror());
- ast_free(resource_being_loaded);
+ ast_free(mod);
return NULL;
}
@@ -585,7 +595,6 @@ static struct ast_module *load_dynamic_module(const char *resource_in, unsigned
time too :) */
AST_DLLIST_LAST(&module_list)->lib = lib;
- resource_being_loaded = NULL;
return AST_DLLIST_LAST(&module_list);
}
@@ -621,9 +630,7 @@ int modules_shutdown(void)
ast_verb(1, "Unloading %s\n", mod->resource);
mod->info->unload();
}
- AST_LIST_HEAD_DESTROY(&mod->users);
- ao2_cleanup(mod->ref_debug);
- ast_free(mod);
+ module_destroy(mod);
somethingchanged = 1;
}
AST_DLLIST_TRAVERSE_BACKWARDS_SAFE_END;