freebsd-skq/lib/libthr/thread/thr_sig.c
David Xu 76a9679f8e If a new thread is created, it inherits current thread's signal masks,
however if current thread is executing cancellation handler, signal
SIGCANCEL may have already been blocked, this is unexpected, unblock the
signal in new thread if this happens.

MFC after: 1 week
2008-03-04 04:28:59 +00:00

394 lines
8.7 KiB
C

/*
* Copyright (c) 2005, David Xu <davidxu@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 "namespace.h"
#include <sys/param.h>
#include <sys/types.h>
#include <sys/signalvar.h>
#include <signal.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include "un-namespace.h"
#include "thr_private.h"
/* #define DEBUG_SIGNAL */
#ifdef DEBUG_SIGNAL
#define DBG_MSG stdout_debug
#else
#define DBG_MSG(x...)
#endif
extern int __pause(void);
int ___pause(void);
int _raise(int);
int __sigtimedwait(const sigset_t *set, siginfo_t *info,
const struct timespec * timeout);
int _sigtimedwait(const sigset_t *set, siginfo_t *info,
const struct timespec * timeout);
int __sigwaitinfo(const sigset_t *set, siginfo_t *info);
int _sigwaitinfo(const sigset_t *set, siginfo_t *info);
int __sigwait(const sigset_t *set, int *sig);
int _sigwait(const sigset_t *set, int *sig);
int __sigsuspend(const sigset_t *sigmask);
static void
sigcancel_handler(int sig __unused,
siginfo_t *info __unused, ucontext_t *ucp __unused)
{
struct pthread *curthread = _get_curthread();
if (curthread->cancel_defer && curthread->cancel_pending)
thr_wake(curthread->tid);
curthread->in_sigcancel_handler = 1;
_thr_ast(curthread);
curthread->in_sigcancel_handler = 0;
}
void
_thr_ast(struct pthread *curthread)
{
if (!THR_IN_CRITICAL(curthread)) {
_thr_testcancel(curthread);
if (__predict_false((curthread->flags &
(THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED))
== THR_FLAGS_NEED_SUSPEND))
_thr_suspend_check(curthread);
}
}
void
_thr_suspend_check(struct pthread *curthread)
{
long cycle;
int err;
err = errno;
/*
* Blocks SIGCANCEL which other threads must send.
*/
_thr_signal_block(curthread);
/*
* Increase critical_count, here we don't use THR_LOCK/UNLOCK
* because we are leaf code, we don't want to recursively call
* ourself.
*/
curthread->critical_count++;
THR_UMUTEX_LOCK(curthread, &(curthread)->lock);
while ((curthread->flags & (THR_FLAGS_NEED_SUSPEND |
THR_FLAGS_SUSPENDED)) == THR_FLAGS_NEED_SUSPEND) {
curthread->cycle++;
cycle = curthread->cycle;
/* Wake the thread suspending us. */
_thr_umtx_wake(&curthread->cycle, INT_MAX);
/*
* if we are from pthread_exit, we don't want to
* suspend, just go and die.
*/
if (curthread->state == PS_DEAD)
break;
curthread->flags |= THR_FLAGS_SUSPENDED;
THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock);
_thr_umtx_wait(&curthread->cycle, cycle, NULL);
THR_UMUTEX_LOCK(curthread, &(curthread)->lock);
curthread->flags &= ~THR_FLAGS_SUSPENDED;
}
THR_UMUTEX_UNLOCK(curthread, &(curthread)->lock);
curthread->critical_count--;
/*
* Unblocks SIGCANCEL, it is possible a new SIGCANCEL is ready and
* a new signal frame will nest us, this seems a problem because
* stack will grow and overflow, but because kernel will automatically
* mask the SIGCANCEL when delivering the signal, so we at most only
* have one nesting signal frame, this should be fine.
*/
_thr_signal_unblock(curthread);
errno = err;
}
void
_thr_signal_init(void)
{
struct sigaction act;
/* Install cancel handler. */
SIGEMPTYSET(act.sa_mask);
act.sa_flags = SA_SIGINFO | SA_RESTART;
act.sa_sigaction = (__siginfohandler_t *)&sigcancel_handler;
__sys_sigaction(SIGCANCEL, &act, NULL);
}
void
_thr_signal_deinit(void)
{
}
__weak_reference(___pause, pause);
int
___pause(void)
{
struct pthread *curthread = _get_curthread();
int ret;
_thr_cancel_enter(curthread);
ret = __pause();
_thr_cancel_leave(curthread);
return ret;
}
__weak_reference(_raise, raise);
int
_raise(int sig)
{
int ret;
if (!_thr_isthreaded())
ret = kill(getpid(), sig);
else
ret = _thr_send_sig(_get_curthread(), sig);
return (ret);
}
__weak_reference(_sigaction, sigaction);
int
_sigaction(int sig, const struct sigaction * act, struct sigaction * oact)
{
/* Check if the signal number is out of range: */
if (sig < 1 || sig > _SIG_MAXSIG || sig == SIGCANCEL) {
/* Return an invalid argument: */
errno = EINVAL;
return (-1);
}
return __sys_sigaction(sig, act, oact);
}
__weak_reference(_sigprocmask, sigprocmask);
int
_sigprocmask(int how, const sigset_t *set, sigset_t *oset)
{
const sigset_t *p = set;
sigset_t newset;
if (how != SIG_UNBLOCK) {
if (set != NULL) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
p = &newset;
}
}
return (__sys_sigprocmask(how, p, oset));
}
__weak_reference(_pthread_sigmask, pthread_sigmask);
int
_pthread_sigmask(int how, const sigset_t *set, sigset_t *oset)
{
if (_sigprocmask(how, set, oset))
return (errno);
return (0);
}
__weak_reference(__sigsuspend, sigsuspend);
int
_sigsuspend(const sigset_t * set)
{
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
ret = __sys_sigsuspend(pset);
return (ret);
}
int
__sigsuspend(const sigset_t * set)
{
struct pthread *curthread = _get_curthread();
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
_thr_cancel_enter(curthread);
ret = __sys_sigsuspend(pset);
_thr_cancel_leave(curthread);
return (ret);
}
__weak_reference(__sigwait, sigwait);
__weak_reference(__sigtimedwait, sigtimedwait);
__weak_reference(__sigwaitinfo, sigwaitinfo);
int
_sigtimedwait(const sigset_t *set, siginfo_t *info,
const struct timespec * timeout)
{
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
ret = __sys_sigtimedwait(pset, info, timeout);
return (ret);
}
int
__sigtimedwait(const sigset_t *set, siginfo_t *info,
const struct timespec * timeout)
{
struct pthread *curthread = _get_curthread();
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
_thr_cancel_enter(curthread);
ret = __sys_sigtimedwait(pset, info, timeout);
_thr_cancel_leave(curthread);
return (ret);
}
int
_sigwaitinfo(const sigset_t *set, siginfo_t *info)
{
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
ret = __sys_sigwaitinfo(pset, info);
return (ret);
}
int
__sigwaitinfo(const sigset_t *set, siginfo_t *info)
{
struct pthread *curthread = _get_curthread();
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
_thr_cancel_enter(curthread);
ret = __sys_sigwaitinfo(pset, info);
_thr_cancel_leave(curthread);
return (ret);
}
int
_sigwait(const sigset_t *set, int *sig)
{
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
ret = __sys_sigwait(pset, sig);
return (ret);
}
int
__sigwait(const sigset_t *set, int *sig)
{
struct pthread *curthread = _get_curthread();
sigset_t newset;
const sigset_t *pset;
int ret;
if (SIGISMEMBER(*set, SIGCANCEL)) {
newset = *set;
SIGDELSET(newset, SIGCANCEL);
pset = &newset;
} else
pset = set;
_thr_cancel_enter(curthread);
ret = __sys_sigwait(pset, sig);
_thr_cancel_leave(curthread);
return (ret);
}