freebsd-dev/lib/libkse/thread/thr_sigaction.c
Maxim Konovalov 0295184c7e o Remove a cruft prevented libpthread sigaction(2) wrapper to
do its work for SIGINFO.  Always install libpthread signal handler
wrapper for SIGINFO even if user SIG_IGN's or SIG_DFL's it.

SIGINFO has a special meaning for libpthread: when LIBPTHREAD_DEBUG
enviroment variable defined it is used for dumping an information
about threads to /tmp/.

Reported by:	mi
Reviewed by:	deischen
MFC after:	2 weeks
2006-06-09 14:23:40 +00:00

131 lines
4.0 KiB
C

/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* 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, 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 <signal.h>
#include <errno.h>
#include <pthread.h>
#include "thr_private.h"
LT10_COMPAT_PRIVATE(_sigaction);
LT10_COMPAT_DEFAULT(sigaction);
__weak_reference(_sigaction, sigaction);
int
_sigaction(int sig, const struct sigaction * act, struct sigaction * oact)
{
int ret = 0;
int err = 0;
struct sigaction newact, oldact;
struct pthread *curthread;
kse_critical_t crit;
/* Check if the signal number is out of range: */
if (sig < 1 || sig > _SIG_MAXSIG) {
/* Return an invalid argument: */
errno = EINVAL;
ret = -1;
} else {
if (act)
newact = *act;
crit = _kse_critical_enter();
curthread = _get_curthread();
KSE_LOCK_ACQUIRE(curthread->kse, &_thread_signal_lock);
oldact = _thread_sigact[sig - 1];
/* Check if a signal action was supplied: */
if (act != NULL) {
/* Set the new signal handler: */
_thread_sigact[sig - 1] = newact;
}
/*
* Check if the kernel needs to be advised of a change
* in signal action:
*/
if (act != NULL) {
newact.sa_flags |= SA_SIGINFO;
/*
* Check if the signal handler is being set to
* the default or ignore handlers:
*/
if (newact.sa_handler != SIG_DFL &&
newact.sa_handler != SIG_IGN) {
/*
* Specify the thread kernel signal
* handler:
*/
newact.sa_handler = (void (*) ())_thr_sig_handler;
}
/*
* Install libpthread signal handler wrapper
* for SIGINFO signal if threads dump enabled
* even if a user set the signal handler to
* SIG_DFL or SIG_IGN.
*/
if (sig == SIGINFO && _thr_dump_enabled()) {
newact.sa_handler =
(void (*) ())_thr_sig_handler;
}
/* Change the signal action in the kernel: */
if (__sys_sigaction(sig, &newact, NULL) != 0) {
_thread_sigact[sig - 1] = oldact;
/* errno is in kse, will copy it to thread */
err = errno;
ret = -1;
}
}
KSE_LOCK_RELEASE(curthread->kse, &_thread_signal_lock);
_kse_critical_leave(crit);
/*
* Check if the existing signal action structure contents are
* to be returned:
*/
if (oact != NULL) {
/* Return the existing signal action contents: */
*oact = oldact;
}
if (ret != 0) {
/* Return errno to thread */
errno = err;
}
}
/* Return the completion status: */
return (ret);
}