/* 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))