From 9a96a86e2d95645f05b160d2efc942c1a3c129d2 Mon Sep 17 00:00:00 2001
From: Matt Jordan <mjordan@digium.com>
Date: Sun, 13 Dec 2015 13:13:55 -0600
Subject: [PATCH] main/utils: Don't emit an ERROR message if the read end of a
pipe closes
An ERROR or WARNING message should generally indicate that something has gone
wrong in Asterisk. In the case of writing to a file descriptor, Asterisk is not
in control of when the far end closes its reading on a file descriptor. If the
far end does close the file descriptor in an unclean fashion, this isn't a bug
or error in Asterisk, particularly when the situation can be gracefully
handled in Asterisk.
Currently, when this happens, a user would see the following somewhat cryptic
ERROR message:
"utils.c: write() returned error: Broken pipe"
There's a few problems with this:
(1) It doesn't provide any context, other than 'something broke a pipe'
(2) As noted, it isn't actually an error in Asterisk
(3) It can get rather spammy if the thing breaking the pipe occurs often, such
as a FastAGI server
(4) Spammy ERROR messages make Asterisk appear to be having issues, or can even
mask legitimate issues
This patch changes ast_carefulwrite to only log an ERROR if we actually had one
that was reasonably under our control. For debugging purposes, we still emit
a debug message if we detect that the far side has stopped reading.
Change-Id: Ia503bb1efcec685fa6f3017bedf98061f8e1b566
---
main/utils.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/main/utils.c b/main/utils.c
index 74932b8c27..db3e4babee 100644
--- a/main/utils.c
+++ b/main/utils.c
@@ -1399,7 +1399,13 @@ int ast_carefulwrite(int fd, char *s, int len, int timeoutms)
if (res < 0 && errno != EAGAIN && errno != EINTR) {
/* fatal error from write() */
- ast_log(LOG_ERROR, "write() returned error: %s\n", strerror(errno));
+ if (errno == EPIPE) {
+#ifndef STANDALONE
+ ast_debug(1, "write() failed due to reading end being closed: %s\n", strerror(errno));
+#endif
+ } else {
+ ast_log(LOG_ERROR, "write() returned error: %s\n", strerror(errno));
+ }
return -1;
}
--
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