pbx: Handle a completely empty dialplan during a context merge

It is highly unlikely, but - at least in Asterisk 12 - theoretically possible
to load Asterisk with no dialplan whatsoever. If that occurs, and some other
module (that is not a pbx module) attempts to merge its contexts into the
dialplan, the existing merge routine will crash. This is because it is not
insane, and rightly believes that you provided some sort of dialplan,
somewhere.

This patch will gracefully merge the contexts in such a case. Note that this
is highly unlikely to occur in 1.8/11, as features will most likely provide
some dialplan via parking. However, in Asterisk 12, parking is now provided
by res_parking, and hence may create its dialplan later.

(closes issue ASTERISK-23297)
Reported by: CJ Oster

Review: https://reviewboard.asterisk.org/r/3222

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@408200 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/main/pbx.c b/main/pbx.c
index e8825140414ab135b69e20378a6925cb5c143ba9..f9cdcf93c4afcc2b32a9324c595c682eb04dcd80 100644 (file)
--- a/main/pbx.c
+++ b/main/pbx.c
@@ -7903,6 +7903,16 @@ void ast_merge_contexts_and_delete(struct ast_context **extcontexts, struct ast_
        begintime = ast_tvnow();
        ast_mutex_lock(&context_merge_lock);/* Serialize ast_merge_contexts_and_delete */
        ast_wrlock_contexts();
+
+       if (!contexts_table) {
+               /* Well, that's odd. There are no contexts. */
+               contexts_table = exttable;
+               contexts = *extcontexts;
+               ast_unlock_contexts();
+               ast_mutex_unlock(&context_merge_lock);
+               return;
+       }
+
        iter = ast_hashtab_start_traversal(contexts_table);
        while ((tmp = ast_hashtab_next(iter))) {
                context_merge(extcontexts, exttable, tmp, registrar);