app_mixmonitor: Fix crashes caused by unloading app_mixmonitor

Unloading app_mixmonitor while active mixmonitors were running would
cause a segfault. This patch fixes that by making it impossible to
unload app_mixmonitor while mixmonitors are active.

Review: https://reviewboard.asterisk.org/r/2624/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@391778 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/apps/app_mixmonitor.c b/apps/app_mixmonitor.c
index a9a4aa46fa02a7e360b9ca6be414ffbf8c5a0d9f..f13edc6ed836280639ec2463cb74ed9f6f8167ae 100644 (file)
--- a/apps/app_mixmonitor.c
+++ b/apps/app_mixmonitor.c
@@ -381,6 +381,8 @@ static void *mixmonitor_thread(void *obj)
 
        ast_verb(2, "End MixMonitor Recording %s\n", mixmonitor->name);
        mixmonitor_free(mixmonitor);
+
+       ast_module_unref(ast_module_info->self);
        return NULL;
 }
 
@@ -414,7 +416,7 @@ static int setup_mixmonitor_ds(struct mixmonitor *mixmonitor, struct ast_channel
        return 0;
 }
 
-static void launch_monitor_thread(struct ast_channel *chan, const char *filename, unsigned int flags,
+static int launch_monitor_thread(struct ast_channel *chan, const char *filename, unsigned int flags,
                                  int readvol, int writevol, const char *post_process) 
 {
        pthread_t thread;
@@ -442,26 +444,26 @@ static void launch_monitor_thread(struct ast_channel *chan, const char *filename
 
        /* Pre-allocate mixmonitor structure and spy */
        if (!(mixmonitor = ast_calloc(1, len))) {
-               return;
+               return -1;
        }
 
        /* Setup the actual spy before creating our thread */
        if (ast_audiohook_init(&mixmonitor->audiohook, AST_AUDIOHOOK_TYPE_SPY, mixmonitor_spy_type)) {
                mixmonitor_free(mixmonitor);
-               return;
+               return -1;
        }
 
        /* Copy over flags and channel name */
        mixmonitor->flags = flags;
        if (!(mixmonitor->autochan = ast_autochan_setup(chan))) {
                mixmonitor_free(mixmonitor);
-               return;
+               return -1;
        }
 
        if (setup_mixmonitor_ds(mixmonitor, chan)) {
                ast_autochan_destroy(mixmonitor->autochan);
                mixmonitor_free(mixmonitor);
-               return;
+               return -1;
        }
        mixmonitor->name = (char *) mixmonitor + sizeof(*mixmonitor);
        strcpy(mixmonitor->name, chan->name);
@@ -485,10 +487,10 @@ static void launch_monitor_thread(struct ast_channel *chan, const char *filename
                        mixmonitor_spy_type, chan->name);
                ast_audiohook_destroy(&mixmonitor->audiohook);
                mixmonitor_free(mixmonitor);
-               return;
+               return -1;
        }
 
-       ast_pthread_create_detached_background(&thread, NULL, mixmonitor_thread, mixmonitor);
+       return ast_pthread_create_detached_background(&thread, NULL, mixmonitor_thread, mixmonitor);
 }
 
 static int mixmonitor_exec(struct ast_channel *chan, const char *data)
@@ -567,7 +569,12 @@ static int mixmonitor_exec(struct ast_channel *chan, const char *data)
        ast_mkdir(tmp, 0777);
 
        pbx_builtin_setvar_helper(chan, "MIXMONITOR_FILENAME", args.filename);
-       launch_monitor_thread(chan, args.filename, flags.flags, readvol, writevol, args.post_process);
+
+       /* If launch_monitor_thread works, the module reference must not be released until it is finished. */
+       ast_module_ref(ast_module_info->self);
+       if (launch_monitor_thread(chan, args.filename, flags.flags, readvol, writevol, args.post_process)) {
+               ast_module_unref(ast_module_info->self);
+       }
 
        return 0;
 }