systemd/0006-core-synchronously-block-when-logging.patch

49 lines
1.7 KiB
Diff
Raw Normal View History

From f173657bccae4dd0cbfe0a7ed33ebc9117b74f05 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 24 Jul 2013 07:24:05 +0200
Subject: [PATCH] core: synchronously block when logging
Previously, the logging sockets were asynchronous and if clogged we'd
lose messages. We did this to be extra careful given that PID 1 might
need to spawn the logging daemon as response to PID 1's own log messages
and we really should avoid a deadlock in that case.
As it turns out this causes loss of too many messages, hence make the
socket blocking again, however put a time limit on it to avoid unbounded
deadlocks in the unlikely case they happen.
https://bugs.freedesktop.org/show_bug.cgi?id=66664
---
src/shared/log.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/src/shared/log.c b/src/shared/log.c
index 27317f7..8f4995a 100644
--- a/src/shared/log.c
+++ b/src/shared/log.c
@@ -115,16 +115,20 @@ void log_close_syslog(void) {
static int create_log_socket(int type) {
int fd;
+ struct timeval tv;
- /* All output to the syslog/journal fds we do asynchronously,
- * and if the buffers are full we just drop the messages */
-
- fd = socket(AF_UNIX, type|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+ fd = socket(AF_UNIX, type|SOCK_CLOEXEC, 0);
if (fd < 0)
return -errno;
fd_inc_sndbuf(fd, SNDBUF_SIZE);
+ /* We need a blocking fd here since we'd otherwise lose
+ messages way too early. However, let's not hang forever in the
+ unlikely case of a deadlock. */
+ timeval_store(&tv, 1*USEC_PER_MINUTE);
+ setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
+
return fd;
}