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authorVladislav Grishenko <themiron@mail.ru>2012-09-12 12:04:48 (GMT)
committerWaldemar Brodkorb <wbx@openadk.org>2015-12-17 19:35:20 (GMT)
commiteaedbdaa0877ec6d0501b8c19ad5175c80764c67 (patch)
tree6c5d538517ff5b9d9d5f8ad7a643eeba958c4093 /libc
parent64917add7f4aeec8720d2fba5e96ea39aac35623 (diff)
Fix syslog messages lost if syslogd is temporary busy
Commit 4139fe5aec935ba3f462dcaf6aafb6e5eadf1ab9 fixes SIGSTOPed syslogd issue. but introduced new one - messages will be lost when socket buffer gets full, not only if syslogd is stalled, but even if it accepts message slower than someone sends and possibly leads to security hole, when important messages get lost as result of attacker flooding. Patch adds 1 second waiting for socket buffer can accept the message, helps when syslogd is working hard. If it's stalled/SIGSTOPed, message will be sent to errout as before. After that, further non-blocking /dev/log connect attempts will fail immediately with EAGAIN error until syslogd reads some from it. function old new delta openlog_intern 259 355 +96 static.tv - 8 +8 .rodata 151 159 +8 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 2/0 up/down: 112/0) Total: 112 bytes Signed-off-by: Vladislav Grishenko <themiron@mail.ru>
Diffstat (limited to 'libc')
-rw-r--r--libc/misc/syslog/syslog.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/libc/misc/syslog/syslog.c b/libc/misc/syslog/syslog.c
index 72afabb..1df0d1a 100644
--- a/libc/misc/syslog/syslog.c
+++ b/libc/misc/syslog/syslog.c
@@ -126,6 +126,7 @@ openlog_intern(void)
{
int fd;
int logType = SOCK_DGRAM;
+ static const struct timeval tv = { 1, 0 };
fd = LogFile;
if (fd == -1) {
@@ -143,6 +144,9 @@ openlog_intern(void)
if (fd != -1 && !connected) {
if (connect(fd, &SyslogAddr, sizeof(SyslogAddr)) != -1) {
+ /* We want to block send if e.g. syslogd is SIGSTOPed */
+ fcntl(fd, F_SETFL, ~O_NONBLOCK & fcntl(fd, F_GETFL));
+ setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &tv, sizeof(tv));
connected = 1;
} else {
if (fd != -1) {