Merged revisions 85158 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
r85158 | tilghman | 2007-10-09 16:55:06 -0500 (Tue, 09 Oct 2007) | 5 lines

This commit fixes the following issues:
- Deadlock in ast_write (issue #10406)
- Deadlock in ast_read (issue #10406)
- Possible mutex initialization error in lock.h (issue #10571)

........


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@85176 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 34 insertions, 1 deletions

diff --git a/main/channel.c b/main/channel.c
index 9d8fd0dd1..9cdf0521d 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -2110,6 +2110,7 @@ static void ast_read_generator_actions(struct ast_channel *chan, struct ast_fram
 static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 {
 	struct ast_frame *f = NULL;	/* the return value */
+	struct ast_channel *base = NULL;
 	int blah;
 	int prestate;
 
@@ -2133,6 +2134,23 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 	}
 	prestate = chan->_state;
 
+	/* Check if there's an underlying channel */
+	if (chan->tech->get_base_channel && (base = chan->tech->get_base_channel(chan)) != chan) {
+		int count = 0;
+		while (!base || ast_mutex_trylock(&base->lock)) {
+			if (count++ > 10) {
+				f = &ast_null_frame;
+				goto done;
+			}
+			ast_mutex_unlock(&chan->lock);
+			usleep(1);
+			ast_mutex_lock(&chan->lock);
+			base = chan->tech->get_base_channel(chan);
+		}
+		ast_mutex_unlock(&chan->lock);
+		chan = base;
+	}
+
 	if (!ast_test_flag(chan, AST_FLAG_DEFER_DTMF | AST_FLAG_EMULATE_DTMF | AST_FLAG_IN_DTMF) && 
 	    !ast_strlen_zero(chan->dtmfq) && 
 		(ast_tvzero(chan->dtmf_tv) || ast_tvdiff_ms(ast_tvnow(), chan->dtmf_tv) > AST_MIN_DTMF_GAP) ) {
@@ -2869,7 +2887,22 @@ int ast_write(struct ast_channel *chan, struct ast_frame *fr)
 					ast_log(LOG_WARNING, "Failed to write data to channel monitor write stream\n");
 			}
 		}
-		res = f ? chan->tech->write(chan, f) : 0;
+
+		if (f) {
+			struct ast_channel *base = NULL;
+			if (!chan->tech->get_base_channel || chan == chan->tech->get_base_channel(chan))
+				res = chan->tech->write(chan, f);
+			else {
+				while (chan->tech->get_base_channel && (((base = chan->tech->get_base_channel(chan)) && ast_mutex_trylock(&base->lock)) || base == NULL)) {
+					ast_mutex_unlock(&chan->lock);
+					usleep(1);
+					ast_mutex_lock(&chan->lock);
+				}
+				res = base->tech->write(base, f);
+				ast_mutex_unlock(&base->lock);
+			}
+		} else
+			res = 0;
 		break;
 	case AST_FRAME_NULL:
 	case AST_FRAME_IAX: