channel: Short-circuit ast_channel_get_by_name() on empty arg.

We know that passing a NULL or empty argument to
ast_channel_get_by_name() will never result in a matching channel and
will always result in an error being emitted, so just short-circuit
out in that case.

ASTERISK-28219 #close

Change-Id: I88eadc748e9c6996fc17467b0a05881bbfd00bce

diff --git a/main/channel.c b/main/channel.c
index 8505b1d6f3c6ab5f46df20302261e4c796d97efd..de5e39f5bfc84c769a52e809e53341ab57c54d2a 100644 (file)
--- a/main/channel.c
+++ b/main/channel.c
@@ -1449,17 +1449,17 @@ struct ast_channel *ast_channel_get_by_name_prefix(const char *name, size_t name
        struct ast_channel *chan;
        char *l_name = (char *) name;
 
+       if (ast_strlen_zero(l_name)) {
+               /* We didn't have a name to search for so quit. */
+               return NULL;
+       }
+
        chan = ast_channel_callback(ast_channel_by_name_cb, l_name, &name_len,
                (name_len == 0) /* optimize if it is a complete name match */ ? OBJ_KEY : 0);
        if (chan) {
                return chan;
        }
 
-       if (ast_strlen_zero(l_name)) {
-               /* We didn't have a name to search for so quit. */
-               return NULL;
-       }
-
        /* Now try a search for uniqueid. */
        return ast_channel_callback(ast_channel_by_uniqueid_cb, l_name, &name_len, 0);
 }