freebsd-dev/lib/libthr/thread/thr_kern.c
Mike Makonnen 98a11db62d When suspending a thread if the timeout was very short or
the system call got interrupted and the absolute timeout is
converted to a relative timeout, it may happen that we get a
negative number. In such a case, simply set the timeout to
zero so that if the event that the thread wants to wait for has
happened it can still return successfully, but if it hasn't
happened then the thread doesn't suspend indefinitely. This should
fix certain applications (including mozilla) that seem to hang
indefinitely sometimes.

Noticed and debugged by: Morten Johansen <root@morten-johansen.net>
2004-01-29 09:44:36 +00:00

158 lines
4.2 KiB
C

/*
* Copyright (c) 2003 Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/signalvar.h>
#include <sys/time.h>
#include <sys/timespec.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include "thr_private.h"
/* XXX Why can't I get this from time.h? :-( */
#define timespecsub(vvp, uvp) \
do { \
(vvp)->tv_sec -= (uvp)->tv_sec; \
(vvp)->tv_nsec -= (uvp)->tv_nsec; \
if ((vvp)->tv_nsec < 0) { \
(vvp)->tv_sec--; \
(vvp)->tv_nsec += 1000000000; \
} \
} while (0)
void
_thread_critical_enter(pthread_t pthread)
{
_thread_sigblock();
UMTX_LOCK(&pthread->lock);
}
void
_thread_critical_exit(pthread_t pthread)
{
UMTX_UNLOCK(&pthread->lock);
_thread_sigunblock();
}
void
_thread_sigblock()
{
sigset_t set;
sigset_t sav;
/*
* Block all signals.
*/
SIGFILLSET(set);
SIGADDSET(set, SIGTHR);
#ifdef _PTHREADS_INVARIANTS
SIGDELSET(set, SIGABRT);
#endif
SIGDELSET(set, SIGTRAP);
/* If we have already blocked signals, just up the refcount */
if (++curthread->signest > 1)
return;
PTHREAD_ASSERT(curthread->signest == 1,
("Blocked signal nesting level must be 1!"));
if (__sys_sigprocmask(SIG_SETMASK, &set, &sav)) {
_thread_printf(STDERR_FILENO, "Critical Enter: sig err %d\n",
errno);
abort();
}
curthread->savedsig = sav;
}
void
_thread_sigunblock()
{
sigset_t set;
/* We might be in a nested 'blocked signal' section */
if (--curthread->signest > 0)
return;
PTHREAD_ASSERT(curthread->signest == 0,
("Non-Zero blocked signal nesting level."));
/*
* Restore signals.
*/
set = curthread->savedsig;
if (__sys_sigprocmask(SIG_SETMASK, &set, NULL)) {
_thread_printf(STDERR_FILENO, "Critical Exit: sig err %d\n",
errno);
abort();
}
}
int
_thread_suspend(pthread_t pthread, const struct timespec *abstime)
{
struct timespec remaining;
struct timespec *ts;
siginfo_t info;
int error;
/*
* Compute the remainder of the run time.
*/
if (abstime) {
struct timespec now;
struct timeval tv;
GET_CURRENT_TOD(tv);
TIMEVAL_TO_TIMESPEC(&tv, &now);
remaining = *abstime;
timespecsub(&remaining, &now);
ts = &remaining;
/*
* If the absolute timeout has already passed set the
* relative timeout to 0 sec. so that sigtimedwait()
* returns immediately.
* NOTE: timespecsub() makes sure the tv_nsec member >= 0.
*/
if (ts->tv_sec < 0) {
ts->tv_sec = 0;
ts->tv_nsec = 0;
}
} else
ts = NULL;
error = sigtimedwait(&_thread_suspend_sigset, &info, ts);
error = (error == -1) ? errno : 0;
return (error);
}