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

1 files changed, 10 insertions, 1 deletions

diff --git a/main/pbx.c b/main/pbx.c
index 726677f4a..1e6a24625 100644
--- a/main/pbx.c
+++ b/main/pbx.c
@@ -1612,9 +1612,11 @@ int pbx_exec(struct ast_channel *c,	/*!< Channel */
 	saved_c_appl= ast_channel_appl(c);
 	saved_c_data= ast_channel_data(c);
 
+	ast_channel_lock(c);
 	ast_channel_appl_set(c, app->name);
 	ast_channel_data_set(c, data);
 	ast_channel_publish_snapshot(c);
+	ast_channel_unlock(c);
 
 	if (app->module)
 		u = __ast_module_user_add(app->module, c);
@@ -6281,7 +6283,9 @@ static enum ast_pbx_result __ast_pbx_run(struct ast_channel *c,
 		if (!callid) {
 			callid = ast_create_callid();
 			if (callid) {
+				ast_channel_lock(c);
 				ast_channel_callid_set(c, callid);
+				ast_channel_unlock(c);
 			}
 		}
 		ast_callid_threadassoc_add(callid);
@@ -10249,6 +10253,7 @@ static int pbx_outgoing_attempt(const char *type, struct ast_format_cap *cap, co
 		return -1;
 	}
 
+	ast_channel_lock(dialed);
 	if (vars) {
 		ast_set_variables(dialed, vars);
 	}
@@ -10257,6 +10262,7 @@ static int pbx_outgoing_attempt(const char *type, struct ast_format_cap *cap, co
 		ast_channel_accountcode_set(dialed, account);
 	}
 	ast_set_flag(ast_channel_flags(dialed), AST_FLAG_ORIGINATED);
+	ast_channel_unlock(dialed);
 
 	if (!ast_strlen_zero(cid_num) || !ast_strlen_zero(cid_name)) {
 		struct ast_party_connected_line connected;
@@ -10364,7 +10370,6 @@ static int pbx_outgoing_attempt(const char *type, struct ast_format_cap *cap, co
 			ast_set_variables(failed, vars);
 			snprintf(failed_reason, sizeof(failed_reason), "%d", ast_dial_reason(outgoing->dial, 0));
 			pbx_builtin_setvar_helper(failed, "REASON", failed_reason);
-
 			ast_channel_unlock(failed);
 
 			if (ast_pbx_run(failed)) {
@@ -10666,10 +10671,12 @@ static int pbx_builtin_busy(struct ast_channel *chan, const char *data)
 	ast_indicate(chan, AST_CONTROL_BUSY);
 	/* Don't change state of an UP channel, just indicate
 	   busy in audio */
+	ast_channel_lock(chan);
 	if (ast_channel_state(chan) != AST_STATE_UP) {
 		ast_channel_hangupcause_set(chan, AST_CAUSE_BUSY);
 		ast_setstate(chan, AST_STATE_BUSY);
 	}
+	ast_channel_unlock(chan);
 	wait_for_hangup(chan, data);
 	return -1;
 }
@@ -10682,10 +10689,12 @@ static int pbx_builtin_congestion(struct ast_channel *chan, const char *data)
 	ast_indicate(chan, AST_CONTROL_CONGESTION);
 	/* Don't change state of an UP channel, just indicate
 	   congestion in audio */
+	ast_channel_lock(chan);
 	if (ast_channel_state(chan) != AST_STATE_UP) {
 		ast_channel_hangupcause_set(chan, AST_CAUSE_CONGESTION);
 		ast_setstate(chan, AST_STATE_BUSY);
 	}
+	ast_channel_unlock(chan);
 	wait_for_hangup(chan, data);
 	return -1;
 }