Use thread-local storage to store pj_thread_descs.
authorMark Michelson <mmichelson@digium.com>
Mon, 20 Aug 2012 20:19:52 +0000 (20:19 +0000)
committerMark Michelson <mmichelson@digium.com>
Mon, 20 Aug 2012 20:19:52 +0000 (20:19 +0000)
pj_thread_register() takes a parameter of type pj_thread_desc.
It was assumed that pj_thread_register either used this item
temporarily or made a copy of it. Unfortunately, all it does is
keep a pointer to the structure in thread-local storage. This
means that if our pj_thread_desc goes out of scope, then pjlib
will be referencing bogus data quite often, most commonly on
operations involving a pj_mutex_t.

In our case, our pj_thread_desc was on the stack and went out
of scope very shortly after registering our thread with pjlib.
With this change, the pj_thread_desc is stored in thread-local
storage so the pointer that pjlib keeps in thread-local storage
will reference legitimate memory.

(closes issue ASTERISK-20237)
reported by Jeremy Pepper
Patches:
ASTERISK-20237.patch uploaded by Mark Michelson (license #5049)
Tested by Jeremy Pepper
........

Merged revisions 371571 from http://svn.asterisk.org/svn/asterisk/branches/11

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@371572 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_rtp_asterisk.c

index 6892b18..aa7895b 100644 (file)
@@ -416,17 +416,29 @@ static void ast_rtp_ice_add_remote_candidate(struct ast_rtp_instance *instance,
        ao2_ref(remote_candidate, -1);
 }
 
+AST_THREADSTORAGE(pj_thread_storage);
+
 /*! \brief Function used to check if the calling thread is registered with pjlib. If it is not it will be registered. */
 static void pj_thread_register_check(void)
 {
-       pj_thread_desc desc;
+       pj_thread_desc *desc;
        pj_thread_t *thread;
 
        if (pj_thread_is_registered() == PJ_TRUE) {
                return;
        }
 
-       pj_thread_register("Asterisk Thread", desc, &thread);
+       desc = ast_threadstorage_get(&pj_thread_storage, sizeof(pj_thread_desc));
+       if (!desc) {
+               ast_log(LOG_ERROR, "Could not get thread desc from thread-local storage. Expect awful things to occur\n");
+               return;
+       }
+       pj_bzero(*desc, sizeof(*desc));
+
+       if (pj_thread_register("Asterisk Thread", *desc, &thread) != PJ_SUCCESS) {
+               ast_log(LOG_ERROR, "Coudln't register thread with PJLIB.\n");
+       }
+       return;
 }
 
 /*! \brief Helper function which updates an ast_sockaddr with the candidate used for the component */