Permit zero-length text messages in SIP.

(Related to an issue posted to the -users list, subject "AEL2, BASE64_DECODE and hexadecimal")


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@187362 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_sendtext.c

@@ -78,7 +78,9 @@ static int sendtext_exec(struct ast_channel *chan, void *data)
 		
 	u = ast_module_user_add(chan);	
 
-	if (ast_strlen_zero(data)) {
+	/* NOT ast_strlen_zero, because some protocols (e.g. SIP) MUST be able to
+	 * send a zero-length message. */
+	if (!data) {
 		ast_log(LOG_WARNING, "SendText requires an argument (text[|options])\n");
 		ast_module_user_remove(u);
 		return -1;

channels/chan_sip.c

@@ -2413,7 +2413,9 @@ static int sip_sendtext(struct ast_channel *ast, const char *text)
 		ast_verbose("Sending text %s on %s\n", text, ast->name);
 	if (!p)
 		return -1;
-	if (ast_strlen_zero(text))
+	/* NOT ast_strlen_zero, because a zero-length message is specifically
+	 * allowed by RFC 3428 (See section 10, Examples) */
+	if (!text)
 		return 0;
 	if (debug)
 		ast_verbose("Really sending text %s on %s\n", text, ast->name);