Fix worker thread resource leak in SIP TCP/TLS.

The SIP TCP/TLS worker threads were created joinable but noone could join
them if they died on their own.

* Fix the SIP TCP/TLS worker threads to not be created joinable.

* _sip_tcp_helper_thread() only needs one parameter since the pvt
parameter is only passed in as NULL and never used.

(closes issue ASTERISK-19203)
Reported by: Steve Davies

Review: https://reviewboard.asterisk.org/r/1714/
........

Merged revisions 356677 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@356690 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -1507,7 +1507,7 @@ static int get_domain(const char *str, char *domain, int len);
 static void get_realm(struct sip_pvt *p, const struct sip_request *req);
 
 /*-- TCP connection handling ---*/
-static void *_sip_tcp_helper_thread(struct sip_pvt *pvt, struct ast_tcptls_session_instance *tcptls_session);
+static void *_sip_tcp_helper_thread(struct ast_tcptls_session_instance *tcptls_session);
 static void *sip_tcp_worker_fn(void *);
 
 /*--- Constructing requests and responses */
@@ -2485,7 +2485,7 @@ static void *sip_tcp_worker_fn(void *data)
 {
 	struct ast_tcptls_session_instance *tcptls_session = data;
 
-	return _sip_tcp_helper_thread(NULL, tcptls_session);
+	return _sip_tcp_helper_thread(tcptls_session);
 }
 
 /*! \brief Check if the authtimeout has expired.
@@ -2516,7 +2516,7 @@ static int sip_check_authtimeout(time_t start)
 /*! \brief SIP TCP thread management function
 	This function reads from the socket, parses the packet into a request
 */
-static void *_sip_tcp_helper_thread(struct sip_pvt *pvt, struct ast_tcptls_session_instance *tcptls_session)
+static void *_sip_tcp_helper_thread(struct ast_tcptls_session_instance *tcptls_session)
 {
 	int res, cl, timeout = -1, authenticated = 0, flags, after_poll = 0, need_poll = 1;
 	time_t start;
@@ -26269,6 +26269,7 @@ static int sip_prepare_socket(struct sip_pvt *p)
 	struct ast_tcptls_session_instance *tcptls_session;
 	struct ast_tcptls_session_args *ca;
 	struct ast_sockaddr sa_tmp;
+	pthread_t launched;
 
 	/* check to see if a socket is already active */
 	if ((s->fd != -1) && (s->type == SIP_TRANSPORT_UDP)) {
@@ -26293,7 +26294,7 @@ static int sip_prepare_socket(struct sip_pvt *p)
 	}
 
 	/* At this point we are dealing with a TCP/TLS connection
-	 * 1. We need to check to see if a connectin thread exists
+	 * 1. We need to check to see if a connection thread exists
 	 *    for this address, if so use that.
 	 * 2. If a thread does not exist for this address, but the tcptls_session
 	 *    exists on the socket, the connection was closed.
@@ -26364,7 +26365,7 @@ static int sip_prepare_socket(struct sip_pvt *p)
 	/* Give the new thread a reference to the tcptls_session */
 	ao2_ref(s->tcptls_session, +1);
 
-	if (ast_pthread_create_background(&ca->master, NULL, sip_tcp_worker_fn, s->tcptls_session)) {
+	if (ast_pthread_create_detached_background(&launched, NULL, sip_tcp_worker_fn, s->tcptls_session)) {
 		ast_debug(1, "Unable to launch '%s'.", ca->name);
 		ao2_ref(s->tcptls_session, -1); /* take away the thread ref we just gave it */
 		goto create_tcptls_session_fail;
@@ -31309,6 +31310,7 @@ static int unload_module(void)
 	struct sip_threadinfo *th;
 	struct ast_context *con;
 	struct ao2_iterator i;
+	int wait_count;
 
 	network_change_event_unsubscribe();
 
@@ -31367,7 +31369,6 @@ static int unload_module(void)
 		pthread_t thread = th->threadid;
 		th->stop = 1;
 		pthread_kill(thread, SIGURG);
-		pthread_join(thread, NULL);
 		ao2_t_ref(th, -1, "decrement ref from iterator");
 	}
 	ao2_iterator_destroy(&i);
@@ -31413,21 +31414,11 @@ static int unload_module(void)
 	sip_epa_unregister_all();
 	destroy_escs();
 
-	if (default_tls_cfg.certfile) {
-		ast_free(default_tls_cfg.certfile);
-	}
-	if (default_tls_cfg.pvtfile) {
-		ast_free(default_tls_cfg.pvtfile);
-	}
-	if (default_tls_cfg.cipher) {
-		ast_free(default_tls_cfg.cipher);
-	}
-	if (default_tls_cfg.cafile) {
-		ast_free(default_tls_cfg.cafile);
-	}
-	if (default_tls_cfg.capath) {
-		ast_free(default_tls_cfg.capath);
-	}
+	ast_free(default_tls_cfg.certfile);
+	ast_free(default_tls_cfg.pvtfile);
+	ast_free(default_tls_cfg.cipher);
+	ast_free(default_tls_cfg.cafile);
+	ast_free(default_tls_cfg.capath);
 
 	cleanup_all_regs();
 	ASTOBJ_CONTAINER_DESTROYALL(&regl, sip_registry_destroy);
@@ -31445,6 +31436,21 @@ static int unload_module(void)
 	ASTOBJ_CONTAINER_DESTROYALL(&submwil, sip_subscribe_mwi_destroy);
 	ASTOBJ_CONTAINER_DESTROY(&submwil);
 
+	/*
+	 * Wait awhile for the TCP/TLS thread container to become empty.
+	 *
+	 * XXX This is a hack, but the worker threads cannot be created
+	 * joinable.  They can die on their own and remove themselves
+	 * from the container thus resulting in a huge memory leak.
+	 */
+	wait_count = 1000;
+	while (ao2_container_count(threadt) && --wait_count) {
+		sched_yield();
+	}
+	if (!wait_count) {
+		ast_debug(2, "TCP/TLS thread container did not become empty :(\n");
+	}
+
 	ao2_t_ref(peers, -1, "unref the peers table");
 	ao2_t_ref(peers_by_ip, -1, "unref the peers_by_ip table");
 	ao2_t_ref(dialogs, -1, "unref the dialogs table");

channels/sip/include/sip.h

@@ -1372,6 +1372,7 @@ struct tcptls_packet {
 };
 /*! \brief Definition of a thread that handles a socket */
 struct sip_threadinfo {
+	/*! TRUE if the thread needs to kill itself.  (The module is being unloaded.) */
 	int stop;
 	int alert_pipe[2];          /*! Used to alert tcptls thread when packet is ready to be written */
 	pthread_t threadid;

include/asterisk/tcptls.h

@@ -128,6 +128,7 @@ struct ast_tcptls_session_args {
 	struct ast_tls_config *tls_cfg; /*!< points to the SSL configuration if any */
 	int accept_fd;
 	int poll_timeout;
+	/*! Server accept_fn thread ID used for external shutdown requests. */
 	pthread_t master;
 	void *(*accept_fn)(void *); /*!< the function in charge of doing the accept */
 	void (*periodic_fn)(void *);/*!< something we may want to run before after select on the accept socket */
@@ -146,6 +147,7 @@ struct ast_tcptls_session_instance {
 	int client;
 	struct ast_sockaddr remote_address;
 	struct ast_tcptls_session_args *parent;
+	/*! XXX Why do we still use this lock when this struct is allocated as an ao2 object which has its own lock? */
 	ast_mutex_t lock;
 };