diff options
author | brian <brian@FreeBSD.org> | 2009-05-26 07:32:08 +0000 |
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committer | brian <brian@FreeBSD.org> | 2009-05-26 07:32:08 +0000 |
commit | a49cea262eb7aeec6c7f9eaf6c5b80911f532e9a (patch) | |
tree | 27c0bde3728f3bec772a715d3fcc7ef7a20b56e9 /usr.sbin | |
parent | 6ffe6436417e46e4117d92d087a8076e81b4fd95 (diff) | |
download | FreeBSD-src-a49cea262eb7aeec6c7f9eaf6c5b80911f532e9a.zip FreeBSD-src-a49cea262eb7aeec6c7f9eaf6c5b80911f532e9a.tar.gz |
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.
PR: 102747
Submitted by: Sergey Zaharchenko - doublef-ctm at yandex dot ru
MFC after: 3 weeks
Diffstat (limited to 'usr.sbin')
-rw-r--r-- | usr.sbin/ppp/timer.c | 37 |
1 files changed, 23 insertions, 14 deletions
diff --git a/usr.sbin/ppp/timer.c b/usr.sbin/ppp/timer.c index 77b2af7..c1b589b7 100644 --- a/usr.sbin/ppp/timer.c +++ b/usr.sbin/ppp/timer.c @@ -1,5 +1,5 @@ /*- - * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org> + * Copyright (c) 1996 - 2001, 2009 Brian Somers <brian@Awfulhak.org> * based on work by Toshiharu OHNO <tony-o@iij.ad.jp> * Internet Initiative Japan, Inc (IIJ) * All rights reserved. @@ -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 *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) |