From 0f8ba377cb458ec0c5de18a450189e701f710a1e Mon Sep 17 00:00:00 2001 From: Jeremy Harris Date: Tue, 27 May 2014 21:50:41 +0100 Subject: [PATCH] Do not sleep for tiny periods, or hang trying to sleep for zero. Bug 1426 --- src/src/exim.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/src/src/exim.c b/src/src/exim.c index 6a2336450..51daa5576 100644 --- a/src/src/exim.c +++ b/src/src/exim.c @@ -267,6 +267,10 @@ will wait for ever, so we panic in this instance. (There was a case of this when a bug in a function that calls milliwait() caused it to pass invalid data. That's when I added the check. :-) +We assume it to be not worth sleeping for under 100us; this value will +require revisiting as hardware advances. This avoids the issue of +a zero-valued timer setting meaning "never fire". + Argument: an itimerval structure containing the interval Returns: nothing */ @@ -276,6 +280,9 @@ milliwait(struct itimerval *itval) { sigset_t sigmask; sigset_t old_sigmask; + +if (itval->it_value.tv_usec < 100 && itval->it_value.tv_sec == 0) + return; (void)sigemptyset(&sigmask); /* Empty mask */ (void)sigaddset(&sigmask, SIGALRM); /* Add SIGALRM */ (void)sigprocmask(SIG_BLOCK, &sigmask, &old_sigmask); /* Block SIGALRM */ @@ -310,8 +317,7 @@ struct itimerval itval; itval.it_interval.tv_sec = 0; itval.it_interval.tv_usec = 0; itval.it_value.tv_sec = msec/1000; -if ((itval.it_value.tv_usec = (msec % 1000) * 1000) == 0) - itval.it_value.tv_usec = 1; +itval.it_value.tv_usec = (msec % 1000) * 1000; milliwait(&itval); } -- 2.30.2