/*      $OpenBSD: sigsuspend.c,v 1.5 2012/02/20 01:51:32 guenther Exp $ */
/*
 * Copyright (c) 1998 Daniel M. Eischen <eischen@vigrid.com>
 * 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 Daniel M. Eischen.
 * 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 DANIEL M. EISCHEN 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 REGENTS 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.
 *
 */
#include <stdlib.h>
#include <unistd.h>

#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>

#include <pthread_np.h>
#include "test.h"

static int      sigcounts[NSIG + 1];
static int      sigfifo[NSIG + 1];
static int      fifo_depth = 0;
static sigset_t suspender_mask;
static pthread_t suspender_tid;


static void *
sigsuspender (void *arg)
{
        int save_count, status, i;
        sigset_t run_mask;

        SET_NAME("sigsuspender");

        /* Run with all signals blocked. */
        sigfillset (&run_mask);
        CHECKe(sigprocmask (SIG_SETMASK, &run_mask, NULL));

        /* Allow these signals to wake us up during a sigsuspend. */
        sigfillset (&suspender_mask);           /* Default action       */
        sigdelset (&suspender_mask, SIGINT);    /* terminate            */
        sigdelset (&suspender_mask, SIGHUP);    /* terminate            */
        sigdelset (&suspender_mask, SIGQUIT);   /* create core image    */
        sigdelset (&suspender_mask, SIGURG);    /* ignore               */
        sigdelset (&suspender_mask, SIGIO);     /* ignore               */
        sigdelset (&suspender_mask, SIGUSR2);   /* terminate            */
        sigdelset (&suspender_mask, SIGSTOP);   /* unblockable          */
        sigdelset (&suspender_mask, SIGKILL);   /* unblockable          */

        while (sigcounts[SIGINT] == 0) {
                save_count = sigcounts[SIGUSR2];

                status = sigsuspend (&suspender_mask);
                if ((status == 0) || (errno != EINTR)) {
                        DIE(errno, "Unable to suspend for signals, "
                                "return value %d\n",
                                status);
                }
                for (i = 0; i < fifo_depth; i++)
                        printf ("Sigsuspend woke up by signal %d (%s)\n",
                                sigfifo[i], strsignal(sigfifo[i]));
                fifo_depth = 0;
        }

        return (arg);
}


static void
sighandler (int signo)
{
        int save_errno = errno;
        char buf[8192];
        sigset_t set;
        sigset_t tmp;
        pthread_t self;

        if ((signo >= 0) && (signo <= NSIG))
                sigcounts[signo]++;

        /*
         * If we are running on behalf of the suspender thread,
         * ensure that we have the correct mask set.   NOTE: per
         * POSIX the current signo will be part of the mask unless
         * SA_NODEFER was specified.   Since it isn't in this test
         * add the current signal to the original suspender_mask
         * before checking.
         */
        self = pthread_self ();
        if (self == suspender_tid) {
                sigfifo[fifo_depth] = signo;
                fifo_depth++;
                snprintf(buf, sizeof buf,
                    "  -> Suspender thread signal handler caught "
                        "signal %d (%s)\n", signo, strsignal(signo));
                write(STDOUT_FILENO, buf, strlen(buf));
                sigprocmask (SIG_SETMASK, NULL, &set);
                tmp = suspender_mask;
                sigaddset(&tmp, signo);
                sigdelset(&tmp, SIGTHR);
                sigdelset(&set, SIGTHR);
                ASSERT(set == tmp);
        } else {
                snprintf(buf, sizeof buf,
                    "  -> Main thread signal handler caught "
                        "signal %d (%s)\n", signo, strsignal(signo));
                write(STDOUT_FILENO, buf, strlen(buf));
        }
        errno = save_errno;
}


int main (int argc, char *argv[])
{
        pthread_attr_t  pattr;
        struct sigaction act;
        sigset_t        oldset;
        sigset_t        newset;

        /* Initialize our signal counts. */
        memset ((void *) sigcounts, 0, NSIG * sizeof (int));

        /* Ignore signal SIGIO. */
        sigemptyset (&act.sa_mask);
        sigaddset (&act.sa_mask, SIGIO);
        act.sa_handler = SIG_IGN;
        act.sa_flags = 0;
        CHECKe(sigaction (SIGIO, &act, NULL));

        /* Install a signal handler for SIGURG. */
        sigemptyset (&act.sa_mask);
        sigaddset (&act.sa_mask, SIGURG);
        act.sa_handler = sighandler;
        act.sa_flags = SA_RESTART;
        CHECKe(sigaction (SIGURG, &act, NULL));

        /* Install a signal handler for SIGXCPU */
        sigemptyset (&act.sa_mask);
        sigaddset (&act.sa_mask, SIGXCPU);
        CHECKe(sigaction (SIGXCPU, &act, NULL));

        /* Get our current signal mask. */
        CHECKe(sigprocmask (SIG_SETMASK, NULL, &oldset));

        /* Mask out SIGUSR1 and SIGUSR2. */
        newset = oldset;
        sigaddset (&newset, SIGUSR1);
        sigaddset (&newset, SIGUSR2);
        CHECKe(sigprocmask (SIG_SETMASK, &newset, NULL));

        /* Install a signal handler for SIGUSR1 and SIGUSR2 */
        sigemptyset (&act.sa_mask);
        sigaddset (&act.sa_mask, SIGUSR1);
        sigaddset (&act.sa_mask, SIGUSR2);
        act.sa_handler = sighandler;
        act.sa_flags = SA_RESTART;
        CHECKe(sigaction (SIGUSR1, &act, NULL));
        CHECKe(sigaction (SIGUSR2, &act, NULL));

        /*
         * Initialize the thread attribute.
         */
        CHECKr(pthread_attr_init (&pattr));
        CHECKr(pthread_attr_setdetachstate (&pattr, PTHREAD_CREATE_JOINABLE));

        /*
         * Create the sigsuspender thread.
         */
        CHECKr(pthread_create (&suspender_tid, &pattr, sigsuspender, NULL));

        /*
         * Verify that an ignored signal doesn't cause a wakeup.
         * We don't have a handler installed for SIGIO.
         */
        CHECKr(pthread_kill (suspender_tid, SIGIO));
        sleep (1);
        CHECKe(kill (getpid (), SIGIO));
        sleep (1);
        /* sigsuspend should not wake up for ignored signal SIGIO */
        ASSERT(sigcounts[SIGIO] == 0);

        /*
         * Verify that a signal with a default action of ignore, for
         * which we have a signal handler installed, will release a
         * sigsuspend.
         */
        CHECKr(pthread_kill (suspender_tid, SIGURG));
        sleep (1);
        CHECKe(kill (getpid (), SIGURG));
        sleep (1);
        /* sigsuspend should wake up for SIGURG */
        ASSERT(sigcounts[SIGURG] == 2);

        /*
         * Verify that a SIGUSR2 signal will release a sigsuspended
         * thread.
         */
        CHECKr(pthread_kill (suspender_tid, SIGUSR2));
        sleep (1);
        CHECKe(kill (getpid (), SIGUSR2));
        sleep (1);
        /* sigsuspend should wake up for SIGUSR2 */
        ASSERT(sigcounts[SIGUSR2] == 2);

        /*
         * Verify that a signal, blocked in both the main and
         * sigsuspender threads, does not cause the signal handler
         * to be called.
         */
        CHECKr(pthread_kill (suspender_tid, SIGUSR1));
        sleep (1);
        CHECKe(kill (getpid (), SIGUSR1));
        sleep (1);
        /* signal handler should not be called for USR1 */
        ASSERT(sigcounts[SIGUSR1] == 0);
#if 0
        /*
         * Verify that we can still kill the process for a signal
         * not being waited on by sigwait.
         */
        CHECKe(kill (getpid (), SIGPIPE));
        PANIC("SIGPIPE did not terminate process");

        /*
         * Wait for the thread to finish.
         */
        CHECKr(pthread_join (suspender_tid, NULL));
#endif
        SUCCEED;
}