From 700d4501b8339e7b0e0e89b993f14f1f6d6cc17d Mon Sep 17 00:00:00 2001
From: Tilghman Lesher <tilghman@meg.abyt.es>
Date: Wed, 6 Aug 2008 03:55:49 +0000
Subject: [PATCH] Merged revisions 135949 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.4
........
r135949 | tilghman | 2008-08-05 22:53:36 -0500 (Tue, 05 Aug 2008) | 4 lines
Fix a longstanding bug in channel walking logic, and fix the explanation to
make sense.
(Closes issue #13124)
........
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@135950 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
main/channel.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/main/channel.c b/main/channel.c
index 276b3687c8..431dd223ec 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -1117,24 +1117,27 @@ static struct ast_channel *channel_find_locked(const struct ast_channel *prev,
for (retries = 0; retries < 200; retries++) {
int done;
+ /* Reset prev on each retry. See note below for the reason. */
+ prev = _prev;
AST_RWLIST_RDLOCK(&channels);
AST_RWLIST_TRAVERSE(&channels, c, chan_list) {
- prev = _prev;
- if (prev) { /* look for next item */
+ if (prev) { /* look for last item, first, before any evaluation */
if (c != prev) /* not this one */
continue;
/* found, prepare to return c->next */
if ((c = AST_RWLIST_NEXT(c, chan_list)) == NULL) break;
- /* If prev was the last item on the channel list, then we just
- * want to return NULL, instead of trying to deref NULL in the
- * next section.
+ /*!\note
+ * We're done searching through the list for the previous item.
+ * Any item after this point, we want to evaluate for a match.
+ * If we didn't set prev to NULL here, then we would only
+ * return matches for the first matching item (since the above
+ * "if (c != prev)" would not permit any other potential
+ * matches to reach the additional matching logic, below).
+ * Instead, it would just iterate until it once again found the
+ * original match, then iterate down to the end of the list and
+ * quit.
*/
prev = NULL;
- /* We want prev to be NULL in case we end up doing more searching through
- * the channel list to find the channel (ie: name searching). If we didn't
- * set this to NULL the logic would just blow up
- * XXX Need a better explanation for this ...
- */
}
if (name) { /* want match by name */
if ((!namelen && strcasecmp(c->name, name) && strcmp(c->uniqueid, name)) ||
--
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