From e2f49af37f6a23dc3edca17cf2f1f159f342e2e3 Mon Sep 17 00:00:00 2001
From: Mark Michelson <mmichelson@digium.com>
Date: Fri, 16 Jan 2009 19:54:39 +0000
Subject: [PATCH] Fix a logic error that occur when using the timerfd interface
This sequence of events posed a problem
timerfd_timer_open
timerfd_timer_enable_continuous
timerfd_timer_set_rate
timerfd_timer_disable_continuous
The reason was that the timing module was written under the assumption
that timerfd_timer_set_rate would not be called between enabling and
disabling continuous mode. What happened in this situation was that
timerfd_timer_enable_continuous saved off our previously set timer (in this
situation a 0 timer, meaning it never runs out). Then timerfd_timer_disable_continuous
would restore this 0 timer, even though it logically should set the timer to be whatever
was set in timerfd_timer_set_rate.
Now the behavior in timerfd_timer_set_rate is to overwrite the saved timer that may
or may not have been set in timerfd_timer_enable_continuous. Even if
timerfd_timer_enable_continuous has not been previously called, this will not harm the
operation.
Thanks to Terry Wilson for discovering the problem and giving me a really great debug
capture that pointed out the problem clearly
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@168898 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
res/res_timing_timerfd.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/res/res_timing_timerfd.c b/res/res_timing_timerfd.c
index d0ad175204..60dc2d5efb 100644
--- a/res/res_timing_timerfd.c
+++ b/res/res_timing_timerfd.c
@@ -131,13 +131,21 @@ static void timerfd_timer_close(int handle)
static int timerfd_timer_set_rate(int handle, unsigned int rate)
{
- struct itimerspec itspec;
- itspec.it_value.tv_sec = 0;
- itspec.it_value.tv_nsec = rate ? (long) (1000000000 / rate) : 0L;
- itspec.it_interval.tv_sec = itspec.it_value.tv_sec;
- itspec.it_interval.tv_nsec = itspec.it_value.tv_nsec;
+ struct timerfd_timer *our_timer, find_helper = {
+ .handle = handle,
+ };
+
+ if (!(our_timer = ao2_find(timerfd_timers, &find_helper, OBJ_POINTER))) {
+ ast_log(LOG_ERROR, "Couldn't find timer with handle %d\n", handle);
+ return -1;
+ }
+
+ our_timer->saved_timer.it_value.tv_sec = 0;
+ our_timer->saved_timer.it_value.tv_nsec = rate ? (long) (1000000000 / rate) : 0L;
+ our_timer->saved_timer.it_interval.tv_sec = our_timer->saved_timer.it_value.tv_sec;
+ our_timer->saved_timer.it_interval.tv_nsec = our_timer->saved_timer.it_value.tv_nsec;
- return timerfd_settime(handle, 0, &itspec, NULL);
+ return timerfd_settime(handle, 0, &our_timer->saved_timer, NULL);
}
static void timerfd_timer_ack(int handle, unsigned int quantity)
--
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