Fix timeouts for ast_waitfordigit[_full].

ast_waitfordigit_full would simply pass its timeout to ast_waitfor_nandfds,
expecting it to decrement the timeout by however many milliseconds were
waited. This is a problem if it consistently waits less than 1ms. The timeout
will never be decremented, and we wait... FOREVER!

This patch makes ast_waitfordigit_full manage the timeout itself. It maintains
the previously undocumented behavior that negative timeouts wait forever.

(closes issue ASTERISK-20375)
Reported by: Mark Michelson
Tested by: Mark Michelson
Review: https://reviewboard.asterisk.org/r/2109/
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Merged revisions 373024 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 373025 from http://svn.asterisk.org/svn/asterisk/branches/10
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Merged revisions 373029 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@373046 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/channel.h

@@ -1896,7 +1896,7 @@ char *ast_recvtext(struct ast_channel *chan, int timeout);
 /*!
  * \brief Waits for a digit
  * \param c channel to wait for a digit on
- * \param ms how many milliseconds to wait
+ * \param ms how many milliseconds to wait (<0 for indefinite).
  * \return Returns <0 on error, 0 on no entry, and the digit on success.
  */
 int ast_waitfordigit(struct ast_channel *c, int ms);
@@ -1905,7 +1905,7 @@ int ast_waitfordigit(struct ast_channel *c, int ms);
  * \brief Wait for a digit
  * Same as ast_waitfordigit() with audio fd for outputting read audio and ctrlfd to monitor for reading.
  * \param c channel to wait for a digit on
- * \param ms how many milliseconds to wait
+ * \param ms how many milliseconds to wait (<0 for indefinite).
  * \param audiofd audio file descriptor to write to if audio frames are received
  * \param ctrlfd control file descriptor to monitor for reading
  * \return Returns 1 if ctrlfd becomes available

main/channel.c

@@ -3530,7 +3530,6 @@ int ast_waitfor(struct ast_channel *c, int ms)
 	return ms;
 }
 
-/* XXX never to be called with ms = -1 */
 int ast_waitfordigit(struct ast_channel *c, int ms)
 {
 	return ast_waitfordigit_full(c, ms, -1, -1);
@@ -3579,8 +3578,10 @@ int ast_settimeout(struct ast_channel *c, unsigned int rate, int (*func)(const v
 	return res;
 }
 
-int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int cmdfd)
+int ast_waitfordigit_full(struct ast_channel *c, int timeout_ms, int audiofd, int cmdfd)
 {
+	struct timeval start = ast_tvnow();
+
 	/* Stop if we're a zombie or need a soft hangup */
 	if (ast_test_flag(ast_channel_flags(c), AST_FLAG_ZOMBIE) || ast_check_hangup(c))
 		return -1;
@@ -3588,13 +3589,27 @@ int ast_waitfordigit_full(struct ast_channel *c, int ms, int audiofd, int cmdfd)
 	/* Only look for the end of DTMF, don't bother with the beginning and don't emulate things */
 	ast_set_flag(ast_channel_flags(c), AST_FLAG_END_DTMF_ONLY);
 
-	/* Wait for a digit, no more than ms milliseconds total. */
-
-	while (ms) {
+	/* Wait for a digit, no more than timeout_ms milliseconds total.
+	 * Or, wait indefinitely if timeout_ms is <0.
+	 */
+	while (ast_tvdiff_ms(ast_tvnow(), start) < timeout_ms || timeout_ms < 0) {
 		struct ast_channel *rchan;
 		int outfd=-1;
+		int ms;
+
+		if (timeout_ms < 0) {
+			ms = timeout_ms;
+		} else {
+			ms = timeout_ms - ast_tvdiff_ms(ast_tvnow(), start);
+			if (ms < 0) {
+				ms = 0;
+			}
+		}
 
 		errno = 0;
+		/* While ast_waitfor_nandfds tries to help by reducing the timeout by how much was waited,
+		 * it is unhelpful if it waited less than a millisecond.
+		 */
 		rchan = ast_waitfor_nandfds(&c, 1, &cmdfd, (cmdfd > -1) ? 1 : 0, NULL, &outfd, &ms);
 
 		if (!rchan && outfd < 0 && ms) {