A fix for userland ppp's timers..
Fix a race that can stall the timer when we remove a timer that has another
timer with a <0.05 second delta next to it.
This is done by avoiding the possibility of updating the first residual
time delta in the timer list to zero.
>From FreeBSD
Index: timer.c
===================================================================
RCS file: /cvs/src/usr.sbin/ppp/ppp/timer.c,v
retrieving revision 1.14
diff -u -p -r1.14 timer.c
--- timer.c 17 Jul 2005 19:13:25 -0000 1.14
+++ timer.c 11 Jul 2009 01:04:31 -0000
@@ -94,9 +94,12 @@ timer_Start(struct pppTimer *tp)
return;
}
- /* Adjust our first delta so that it reflects what's really happening */
+ /*
+ * We just need to insert tp in the correct relative place. We don't
+ * need to adjust TimerList->rest (yet).
+ */
if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
- TimerList->rest = RESTVAL(itimer);
+ ticks = RESTVAL(itimer) - TimerList->rest;
pt = NULL;
for (t = TimerList; t; t = t->next) {
@@ -132,6 +135,7 @@ timer_Start(struct pppTimer *tp)
static void
StopTimerNoBlock(struct pppTimer *tp)
{
+ struct itimerval itimer;
struct pppTimer *t, *pt;
/*
@@ -156,14 +160,11 @@ StopTimerNoBlock(struct pppTimer *tp)
timer_TermService(); /* Terminate Timer Service */
}
if (t->next) {
- if (!pt) { /* t (tp) was the first in the list */
- struct itimerval itimer;
-
- if (getitimer(ITIMER_REAL, &itimer) == 0)
- t->rest = RESTVAL(itimer);
- }
- t->next->rest += t->rest;
- if (!pt) /* t->next is now the first in the list */
+ if (!pt && getitimer(ITIMER_REAL, &itimer) == 0)
+ t->next->rest += RESTVAL(itimer); /* t (tp) was the first in the list
*/
+ else
+ t->next->rest += t->rest;
+ if (!pt && t->next->rest > 0) /* t->next is now the first in the list
*/
timer_InitService(1);
}
} else {
@@ -235,11 +236,19 @@ timer_Show(int LogLevel, struct prompt *
{
struct itimerval itimer;
struct pppTimer *pt;
- u_long rest = 0;
+ long rest;
- /* Adjust our first delta so that it reflects what's really happening */
+ /*
+ * Adjust the base time so that the deltas reflect what's really
+ * happening. Changing TimerList->rest might cause it to become zero
+ * (if getitimer() returns a value close to zero), and the
+ * timer_InitService() call will call setitimer() with zero it_value,
+ * stopping the itimer... so be careful!
+ */
if (TimerList && getitimer(ITIMER_REAL, &itimer) == 0)
- TimerList->rest = RESTVAL(itimer);
+ rest = RESTVAL(itimer) - TimerList->rest;
+ else
+ rest = 0;
#define SECS(val) ((val) / SECTICKS)
#define HSECS(val) (((val) % SECTICKS) * 100 / SECTICKS)
--
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