/* vi: set sw=4 ts=4: */ /* sigwait * * Copyright (C) 2003 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; if not, write to the Free * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA * 02111-1307 USA. */ #include <errno.h> #include <signal.h> #include <string.h> #if defined __UCLIBC_HAS_REALTIME__ int sigwait(const sigset_t *set, int *sig) { int ret = sigwaitinfo(set, NULL); if (ret != -1) { *sig = ret; return 0; } return 1; } #else /* __UCLIBC_HAS_REALTIME__ */ /* variant without REALTIME extensions */ static smallint was_sig; /* obviously not thread-safe */ static void ignore_signal(int sig) { was_sig = sig; } int 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. */ 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 /* __UCLIBC_HAS_REALTIME__ */