scratch build was tested and fix confirmed. I think we should also
reschedule all existing tevent timers, we don't have an infrastructure
to do it though.
From 09e5ad3448694d9609bd2a9e89e8a05ef82f66bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20B=C5=99ezina?= <pbrez...@redhat.com>
Date: Mon, 22 Aug 2016 13:15:04 +0200
Subject: [PATCH] watchdog: cope with time shift
Resolves:
https://fedorahosted.org/sssd/ticket/3154
---
src/util/util_watchdog.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/src/util/util_watchdog.c b/src/util/util_watchdog.c
index 5032fddba1b94b3fc7e560162c392dfa57d699cf..178ff92d5c6b950d008620401235474499ba595d 100644
--- a/src/util/util_watchdog.c
+++ b/src/util/util_watchdog.c
@@ -29,8 +29,39 @@ struct watchdog_ctx {
struct timeval interval;
struct tevent_timer *te;
volatile int ticks;
+
+ /* To detect time shift. */
+ struct tevent_context *ev;
+ int input_interval;
+ time_t timestamp;
} watchdog_ctx;
+bool watchdog_detect_timeshift(void)
+{
+ time_t prev_time;
+ time_t cur_time;
+ errno_t ret;
+
+ prev_time = watchdog_ctx.timestamp;
+ cur_time = watchdog_ctx.timestamp = time(NULL);
+ if (cur_time < prev_time) {
+ /* Time shift detected. We need to restart watchdog. */
+ DEBUG(SSSDBG_IMPORTANT_INFO, "Time shift detected, "
+ "restarting watchdog!\n");
+ teardown_watchdog();
+ ret = setup_watchdog(watchdog_ctx.ev, watchdog_ctx.input_interval);
+ if (ret != EOK) {
+ DEBUG(SSSDBG_FATAL_FAILURE, "Unable to restart watchdog "
+ "[%d]: %s\n", ret, sss_strerror(ret));
+ orderly_shutdown(1);
+ }
+
+ return true;
+ }
+
+ return false;
+}
+
/* the watchdog is purposefully *not* handled by the tevent
* signal handler as it is meant to check if the daemon is
* still processing the event queue itself. A stuck process
@@ -38,6 +69,12 @@ struct watchdog_ctx {
* signals either */
static void watchdog_handler(int sig)
{
+ /* Do not count ticks if time shift was detected
+ * since watchdog was restarted. */
+ if (watchdog_detect_timeshift()) {
+ return;
+ }
+
/* if 3 ticks passed by kills itself */
if (__sync_add_and_fetch(&watchdog_ctx.ticks, 1) > 3) {
@@ -101,6 +138,10 @@ int setup_watchdog(struct tevent_context *ev, int interval)
watchdog_ctx.interval.tv_sec = interval;
watchdog_ctx.interval.tv_usec = 0;
+ watchdog_ctx.ev = ev;
+ watchdog_ctx.input_interval = interval;
+ watchdog_ctx.timestamp = time(NULL);
+
/* Start the timer */
/* we give 1 second head start to the watchdog event */
its.it_value.tv_sec = interval + 1;
--
2.1.0
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