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/* vi: set sw=4 ts=4: */
/* sigwait
*
* Copyright (C) 2006 by Steven J. Hill <sjhill@realitydiluted.com>
* Copyright (C) 2003-2005 by Erik Andersen <andersen@uclibc.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* The GNU C Library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with the GNU C Library; see the file COPYING.LIB. If
* not, see <http://www.gnu.org/licenses/>.
*/
#define __need_NULL
#include <stddef.h>
#include <sys/syscall.h>
#include <signal.h>
#include <cancel.h>
#if defined __NR_rt_sigtimedwait && defined __UCLIBC_HAS_REALTIME__
#include <string.h>
/* Return any pending signal or wait for one for the given time. */
static int __NC(sigwait)(const sigset_t *set, int *sig)
{
int ret;
do
/* we might as well use sigtimedwait and do not care about cancellation */
ret = __NC(sigtimedwait)(set, NULL, NULL);
while (ret == -1 && errno == EINTR);
if (ret != -1) {
*sig = ret;
ret = 0;
} else
ret = errno;
return ret;
}
#else /* __NR_rt_sigtimedwait */
/* variant without REALTIME extensions */
#include <unistd.h> /* smallint */
static smallint was_sig; /* obviously not thread-safe */
static void ignore_signal(int sig)
{
was_sig = sig;
}
static int __NC(sigwait)(const sigset_t *set, int *sig)
{
sigset_t tmp_mask;
struct sigaction saved[NSIG];
struct sigaction action;
int save_errno;
int this;
/* Prepare set. */
__sigfillset (&tmp_mask);
/* Unblock all signals in the SET and register our nice handler. */
action.sa_handler = ignore_signal;
action.sa_flags = 0;
__sigfillset (&action.sa_mask); /* Block all signals for handler. */
/* Make sure we recognize error conditions by setting WAS_SIG to a
value which does not describe a legal signal number. */
was_sig = -1;
for (this = 1; this < NSIG; ++this)
if (__sigismember (set, this))
{
/* Unblock this signal. */
__sigdelset (&tmp_mask, this);
/* Register temporary action handler. */
/* In Linux (as of 2.6.25), fails only if sig is SIGKILL or SIGSTOP */
/* (so, will it work correctly if set has, say, SIGSTOP?) */
if (sigaction (this, &action, &saved[this]) != 0)
goto restore_handler;
}
/* Now we can wait for signals. */
__NC(sigsuspend)(&tmp_mask);
restore_handler:
save_errno = errno;
while (--this >= 1)
if (__sigismember (set, this))
/* We ignore errors here since we must restore all handlers. */
sigaction (this, &saved[this], NULL);
__set_errno (save_errno);
/* Store the result and return. */
*sig = was_sig;
return was_sig == -1 ? -1 : 0;
}
#endif /* __NR_rt_sigtimedwait */
CANCELLABLE_SYSCALL(int, sigwait, (const sigset_t *set, int *sig), (set, sig))
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