channel locking: Add locking for channel snapshot creation

Original commit message by mmichelson (asterisk 12 r403311):

"This adds channel locks around calls to create channel snapshots as well
as other functions which operate on a channel and then end up
creating a channel snapshot. Functions that expect the channel to be
locked prior to being called have had their documentation updated to
indicate such."

The above was initially committed and then reverted at r403398.  The problem
was found to be in core_local.c in the publish_local_bridge_message function.
The ast_unreal_lock_all function locks and adds a reference to the returned
channels and while they were being unlocked they were not being unreffed when
no longer needed.  Fixed by unreffing the channels.

Also in bridge.c a lock was obtained on "other->chan", but then an attempt was
made to unlock "other" and not the previously locked channel.  Fixed by
unlocking "other->chan"

(closes issue ASTERISK-22709)
Reported by: John Bigelow
........

Merged revisions 404237 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@404260 65c4cc65-6c06-0410-ace0-fbb531ad65f3

8 files changed, 43 insertions, 6 deletions

diff --git a/apps/app_agent_pool.c b/apps/app_agent_pool.c
index 2b0d1f8b8..a44c75d46 100644
--- a/apps/app_agent_pool.c
+++ b/apps/app_agent_pool.c
@@ -1465,7 +1465,9 @@ static void agent_logout(struct agent_pvt *agent)
 		ast_bridge_destroy(caller_bridge, AST_CAUSE_USER_BUSY);
 	}
 
+	ast_channel_lock(logged);
 	send_agent_logoff(logged, agent->username, time_logged_in);
+	ast_channel_unlock(logged);
 	ast_verb(2, "Agent '%s' logged out.  Logged in for %ld seconds.\n",
 		agent->username, time_logged_in);
 	ast_channel_unref(logged);
@@ -2046,7 +2048,9 @@ static int agent_login_exec(struct ast_channel *chan, const char *data)
 	ast_verb(2, "Agent '%s' logged in (format %s/%s)\n", agent->username,
 		ast_getformatname(ast_channel_readformat(chan)),
 		ast_getformatname(ast_channel_writeformat(chan)));
+	ast_channel_lock(chan);
 	send_agent_login(chan, agent->username);
+	ast_channel_unlock(chan);
 
 	agent_run(agent, chan);
 	return -1;
diff --git a/apps/app_confbridge.c b/apps/app_confbridge.c
index 300d2c7e1..01ae4256c 100644
--- a/apps/app_confbridge.c
+++ b/apps/app_confbridge.c
@@ -1379,7 +1379,9 @@ static int alloc_playback_chan(struct confbridge_conference *conference)
 	}
 
 	/* To make sure playback_chan has the same language of that profile */
+	ast_channel_lock(conference->playback_chan);
 	ast_channel_language_set(conference->playback_chan, conference->b_profile.language);
+	ast_channel_unlock(conference->playback_chan);
 
 	ast_debug(1, "Created announcer channel '%s' to conference bridge '%s'\n",
 		ast_channel_name(conference->playback_chan), conference->name);
diff --git a/apps/app_dial.c b/apps/app_dial.c
index fdbe05692..99d00f13c 100644
--- a/apps/app_dial.c
+++ b/apps/app_dial.c
@@ -2104,6 +2104,7 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 	struct ast_party_caller caller;
 
 	/* Reset all DIAL variables back to blank, to prevent confusion (in case we don't reset all of them). */
+	ast_channel_lock(chan);
 	ast_channel_stage_snapshot(chan);
 	pbx_builtin_setvar_helper(chan, "DIALSTATUS", "");
 	pbx_builtin_setvar_helper(chan, "DIALEDPEERNUMBER", "");
@@ -2111,6 +2112,7 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 	pbx_builtin_setvar_helper(chan, "ANSWEREDTIME", "");
 	pbx_builtin_setvar_helper(chan, "DIALEDTIME", "");
 	ast_channel_stage_snapshot_done(chan);
+	ast_channel_unlock(chan);
 
 	if (ast_strlen_zero(data)) {
 		ast_log(LOG_WARNING, "Dial requires an argument (technology/resource)\n");
@@ -2443,15 +2445,17 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 			continue;
 		}
 
+		ast_channel_lock(tc);
 		ast_channel_stage_snapshot(tc);
+		ast_channel_unlock(tc);
 
 		ast_channel_get_device_name(tc, device_name, sizeof(device_name));
 		if (!ignore_cc) {
 			ast_cc_extension_monitor_add_dialstring(chan, tmp->interface, device_name);
 		}
-		pbx_builtin_setvar_helper(tc, "DIALEDPEERNUMBER", tmp->number);
 
 		ast_channel_lock_both(tc, chan);
+		pbx_builtin_setvar_helper(tc, "DIALEDPEERNUMBER", tmp->number);
 
 		/* Setup outgoing SDP to match incoming one */
 		if (!AST_LIST_FIRST(&out_chans) && !rest && CAN_EARLY_BRIDGE(peerflags, chan, tc)) {
@@ -2724,8 +2728,10 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 			number = ast_strdupa(number);
 		}
 		ast_channel_unlock(peer);
+		ast_channel_lock(chan);
 		pbx_builtin_setvar_helper(chan, "DIALEDPEERNUMBER", number);
 		ast_channel_stage_snapshot_done(chan);
+		ast_channel_unlock(chan);
 
 		if (!ast_strlen_zero(args.url) && ast_channel_supports_html(peer) ) {
 			ast_debug(1, "app_dial: sendurl=%s.\n", args.url);
@@ -2811,16 +2817,18 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 			/* chan and peer are going into the PBX; as such neither are considered
 			 * outgoing channels any longer */
 			ast_clear_flag(ast_channel_flags(chan), AST_FLAG_OUTGOING);
-			ast_channel_stage_snapshot(peer);
-			ast_clear_flag(ast_channel_flags(peer), AST_FLAG_OUTGOING);
 
 			ast_replace_subargument_delimiter(opt_args[OPT_ARG_GOTO]);
 			ast_parseable_goto(chan, opt_args[OPT_ARG_GOTO]);
 			/* peer goes to the same context and extension as chan, so just copy info from chan*/
+			ast_channel_lock(peer);
+			ast_channel_stage_snapshot(peer);
+			ast_clear_flag(ast_channel_flags(peer), AST_FLAG_OUTGOING);
 			ast_channel_context_set(peer, ast_channel_context(chan));
 			ast_channel_exten_set(peer, ast_channel_exten(chan));
 			ast_channel_priority_set(peer, ast_channel_priority(chan) + 2);
 			ast_channel_stage_snapshot_done(peer);
+			ast_channel_unlock(peer);
 			if (ast_pbx_start(peer)) {
 				ast_autoservice_chan_hangup_peer(chan, peer);
 			}
@@ -2970,7 +2978,9 @@ static int dial_exec_full(struct ast_channel *chan, const char *data, struct ast
 		if (!res) {
 			if (!ast_tvzero(calldurationlimit)) {
 				struct timeval whentohangup = ast_tvadd(ast_tvnow(), calldurationlimit);
+				ast_channel_lock(peer);
 				ast_channel_whentohangup_set(peer, &whentohangup);
+				ast_channel_unlock(peer);
 			}
 			if (!ast_strlen_zero(dtmfcalled)) {
 				ast_verb(3, "Sending DTMF '%s' to the called party.\n", dtmfcalled);
diff --git a/apps/app_disa.c b/apps/app_disa.c
index fe53772f1..9e7412717 100644
--- a/apps/app_disa.c
+++ b/apps/app_disa.c
@@ -381,8 +381,11 @@ static int disa_exec(struct ast_channel *chan, const char *data)
 				ast_set_callerid(chan, ourcidnum, ourcidname, ourcidnum);
 			}
 
-			if (!ast_strlen_zero(acctcode))
+			if (!ast_strlen_zero(acctcode)) {
+				ast_channel_lock(chan);
 				ast_channel_accountcode_set(chan, acctcode);
+				ast_channel_unlock(chan);
+			}
 
 			if (special_noanswer) {
 				ast_clear_flag(&cdr_flags, AST_CDR_FLAG_DISABLE);
diff --git a/apps/app_meetme.c b/apps/app_meetme.c
index feea3b6c5..4621d15b4 100644
--- a/apps/app_meetme.c
+++ b/apps/app_meetme.c
@@ -1384,7 +1384,9 @@ static void meetme_stasis_generate_msg(struct ast_conference *meetme_conference,
 		}
 	}
 
+	ast_channel_lock(chan);
 	msg = ast_channel_blob_create(chan, message_type, json_object);
+	ast_channel_unlock(chan);
 
 	if (!msg) {
 		return;
diff --git a/apps/app_queue.c b/apps/app_queue.c
index d9f0f85d3..e1c8a0042 100644
--- a/apps/app_queue.c
+++ b/apps/app_queue.c
@@ -2040,8 +2040,12 @@ static void queue_publish_multi_channel_blob(struct ast_channel *caller, struct
 	RAII_VAR(struct ast_channel_snapshot *, caller_snapshot, NULL, ao2_cleanup);
 	RAII_VAR(struct ast_channel_snapshot *, agent_snapshot, NULL, ao2_cleanup);
 
+	ast_channel_lock(caller);
 	caller_snapshot = ast_channel_snapshot_create(caller);
+	ast_channel_unlock(caller);
+	ast_channel_lock(agent);
 	agent_snapshot = ast_channel_snapshot_create(agent);
+	ast_channel_unlock(agent);
 
 	if (!caller_snapshot || !agent_snapshot) {
 		return;
@@ -3452,7 +3456,9 @@ static int join_queue(char *queuename, struct queue_ent *qe, enum queue_result *
 				     "Queue", q->name,
 				     "Position", qe->pos,
 				     "Count", q->count);
+		ast_channel_lock(qe->chan);
 		ast_channel_publish_blob(qe->chan, queue_caller_join_type(), blob);
+		ast_channel_unlock(qe->chan);
 		ast_debug(1, "Queue '%s' Join, Channel '%s', Position '%d'\n", q->name, ast_channel_name(qe->chan), qe->pos );
 	}
 	ao2_unlock(q);
@@ -3731,7 +3737,9 @@ static void leave_queue(struct queue_ent *qe)
 					     "Queue", q->name,
 					     "Position", qe->pos,
 					     "Count", q->count);
+			ast_channel_lock(qe->chan);
 			ast_channel_publish_blob(qe->chan, queue_caller_leave_type(), blob);
+			ast_channel_unlock(qe->chan);
 			ast_debug(1, "Queue '%s' Leave, Channel '%s'\n", q->name, ast_channel_name(qe->chan));
 			/* Take us out of the queue */
 			if (prev) {
@@ -4329,10 +4337,13 @@ static void record_abandoned(struct queue_ent *qe)
 			     "Position", qe->pos,
 			     "OriginalPosition", qe->opos,
 			     "HoldTime", (int)(time(NULL) - qe->start));
-	ast_channel_publish_blob(qe->chan, queue_caller_abandon_type(), blob);
 
 	qe->parent->callsabandoned++;
 	ao2_unlock(qe->parent);
+
+	ast_channel_lock(qe->chan);
+	ast_channel_publish_blob(qe->chan, queue_caller_abandon_type(), blob);
+	ast_channel_unlock(qe->chan);
 }
 
 /*! \brief RNA == Ring No Answer. Common code that is executed when we try a queue member and they don't answer. */
diff --git a/apps/app_userevent.c b/apps/app_userevent.c
index e0dafbb9f..f5defd49d 100644
--- a/apps/app_userevent.c
+++ b/apps/app_userevent.c
@@ -114,7 +114,9 @@ static int userevent_exec(struct ast_channel *chan, const char *data)
 		}
 	}
 
+	ast_channel_lock(chan);
 	ast_channel_publish_blob(chan, ast_channel_user_event_type(), blob);
+	ast_channel_unlock(chan);
 	return 0;
 }
 
diff --git a/apps/app_voicemail.c b/apps/app_voicemail.c
index 4dffbbef0..36692981b 100644
--- a/apps/app_voicemail.c
+++ b/apps/app_voicemail.c
@@ -10958,8 +10958,11 @@ static int vm_execmain(struct ast_channel *chan, const char *data)
 #endif
 
 	/* Set language from config to override channel language */
-	if (!ast_strlen_zero(vmu->language))
+	if (!ast_strlen_zero(vmu->language)) {
+		ast_channel_lock(chan);
 		ast_channel_language_set(chan, vmu->language);
+		ast_channel_unlock(chan);
+	}
 
 	/* Retrieve urgent, old and new message counts */
 	ast_debug(1, "Before open_mailbox\n");