/*-
 * Copyright (c) 2007-2009 Dag-Erling Smørgrav
 * 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
 *    in this position and unchanged.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/wait.h>
#include <sys/event.h>

#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <libutil.h>

/*
 * We need a signal handler so kill(2) will interrupt the child
 * instead of killing it.
 */
static void
signal_handler(int sig)
{
        (void)sig;
}

/*
 * Test that pidfile_open() can create a pidfile and that pidfile_write()
 * can write to it.
 */
static const char *
test_pidfile_uncontested(void)
{
        const char *fn = "test_pidfile_uncontested";
        struct pidfh *pf;
        pid_t other = 0;

        unlink(fn);
        pf = pidfile_open(fn, 0600, &other);
        if (pf == NULL && other != 0)
                return ("pidfile exists and is locked");
        if (pf == NULL)
                return (strerror(errno));
        if (pidfile_write(pf) != 0) {
                pidfile_close(pf);
                unlink(fn);
                return ("failed to write PID");
        }
        pidfile_close(pf);
        unlink(fn);
        return (NULL);
}

/*
 * Test that pidfile_open() locks against self.
 */
static const char *
test_pidfile_self(void)
{
        const char *fn = "test_pidfile_self";
        struct pidfh *pf1, *pf2;
        pid_t other = 0;
        int serrno;

        unlink(fn);
        pf1 = pidfile_open(fn, 0600, &other);
        if (pf1 == NULL && other != 0)
                return ("pidfile exists and is locked");
        if (pf1 == NULL)
                return (strerror(errno));
        if (pidfile_write(pf1) != 0) {
                serrno = errno;
                pidfile_close(pf1);
                unlink(fn);
                return (strerror(serrno));
        }
        // second open should fail
        pf2 = pidfile_open(fn, 0600, &other);
        if (pf2 != NULL) {
                pidfile_close(pf1);
                pidfile_close(pf2);
                unlink(fn);
                return ("managed to opened pidfile twice");
        }
        if (other != getpid()) {
                pidfile_close(pf1);
                unlink(fn);
                return ("pidfile contained wrong PID");
        }
        pidfile_close(pf1);
        unlink(fn);
        return (NULL);
}

/*
 * Common code for test_pidfile_{contested,inherited}.
 */
static const char *
common_test_pidfile_child(const char *fn, int parent_open)
{
        struct pidfh *pf = NULL;
        pid_t other = 0, pid = 0;
        int fd[2], serrno, status;
        struct kevent event, ke;
        char ch;
        int kq;

        unlink(fn);
        if (pipe(fd) != 0)
                return (strerror(errno));

        if (parent_open) {
                pf = pidfile_open(fn, 0600, &other);
                if (pf == NULL && other != 0)
                        return ("pidfile exists and is locked");
                if (pf == NULL)
                        return (strerror(errno));
        }

        pid = fork();
        if (pid == -1)
                return (strerror(errno));
        if (pid == 0) {
                // child
                close(fd[0]);
                signal(SIGINT, signal_handler);
                if (!parent_open) {
                        pf = pidfile_open(fn, 0600, &other);
                        if (pf == NULL && other != 0)
                                return ("pidfile exists and is locked");
                        if (pf == NULL)
                                return (strerror(errno));
                }
                if (pidfile_write(pf) != 0) {
                        serrno = errno;
                        pidfile_close(pf);
                        unlink(fn);
                        return (strerror(serrno));
                }
                if (pf == NULL)
                        _exit(1);
                if (pidfile_write(pf) != 0)
                        _exit(2);
                kq = kqueue();
                if (kq == -1)
                        _exit(3);
                EV_SET(&ke, SIGINT, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
                /* Attach event to the kqueue. */
                if (kevent(kq, &ke, 1, NULL, 0, NULL) != 0)
                        _exit(4);
                /* Inform the parent we are ready to receive SIGINT */
                if (write(fd[1], "*", 1) != 1)
                        _exit(5);
                /* Wait for SIGINT received */
                if (kevent(kq, NULL, 0, &event, 1, NULL) != 1)
                        _exit(6);
                _exit(0);
        }
        // parent
        close(fd[1]);
        if (pf)
                pidfile_close(pf);

        // wait for the child to signal us
        if (read(fd[0], &ch, 1) != 1) {
                serrno = errno;
                unlink(fn);
                kill(pid, SIGTERM);
                errno = serrno;
                return (strerror(errno));
        }

        // We shouldn't be able to lock the same pidfile as our child
        pf = pidfile_open(fn, 0600, &other);
        if (pf != NULL) {
                pidfile_close(pf);
                unlink(fn);
                return ("managed to lock contested pidfile");
        }

        // Failed to lock, but not because it was contested
        if (other == 0) {
                unlink(fn);
                return (strerror(errno));
        }

        // Locked by the wrong process
        if (other != pid) {
                unlink(fn);
                return ("pidfile contained wrong PID");
        }

        // check our child's fate
        if (pf)
                pidfile_close(pf);
        unlink(fn);
        if (kill(pid, SIGINT) != 0)
                return (strerror(errno));
        if (waitpid(pid, &status, 0) == -1)
                return (strerror(errno));
        if (WIFSIGNALED(status))
                return ("child caught signal");
        if (WEXITSTATUS(status) != 0) 
                return ("child returned non-zero status");

        // success
        return (NULL);
}

/*
 * Test that pidfile_open() fails when attempting to open a pidfile that
 * is already locked, and that it returns the correct PID.
 */
static const char *
test_pidfile_contested(void)
{
        const char *fn = "test_pidfile_contested";
        const char *result;

        result = common_test_pidfile_child(fn, 0);
        return (result);
}

/*
 * Test that the pidfile lock is inherited.
 */
static const char *
test_pidfile_inherited(void)
{
        const char *fn = "test_pidfile_inherited";
        const char *result;

        result = common_test_pidfile_child(fn, 1);
        return (result);
}

/*
 * Make sure we handle relative pidfile paths correctly.
 */
static const char *
test_pidfile_relative(void)
{
        char path[PATH_MAX], pid[32], tmpdir[PATH_MAX];
        struct pidfh *pfh;
        int fd;

        (void)snprintf(tmpdir, sizeof(tmpdir), "%s.XXXXXX", __func__);
        if (mkdtemp(tmpdir) == NULL)
                return (strerror(errno));
        (void)snprintf(path, sizeof(path), "%s/pidfile", tmpdir);

        pfh = pidfile_open(path, 0600, NULL);
        if (pfh == NULL)
                return (strerror(errno));
        if (pidfile_write(pfh) != 0)
                return (strerror(errno));
        fd = open(path, O_RDONLY);
        if (fd < 0)
                return (strerror(errno));
        memset(pid, 0, sizeof(pid));
        if (read(fd, pid, sizeof(pid) - 1) < 0)
                return (strerror(errno));
        if (atoi(pid) != getpid())
                return ("pid mismatch");
        if (close(fd) != 0)
                return (strerror(errno));
        if (pidfile_close(pfh) != 0)
                return (strerror(errno));
        return (NULL);
}

static struct test {
        const char *name;
        const char *(*func)(void);
} t[] = {
        { "pidfile_uncontested", test_pidfile_uncontested },
        { "pidfile_self", test_pidfile_self },
        { "pidfile_contested", test_pidfile_contested },
        { "pidfile_inherited", test_pidfile_inherited },
        { "pidfile_relative", test_pidfile_relative },
};

int
main(void)
{
        const char *result;
        int i, nt;

        nt = sizeof(t) / sizeof(*t);
        printf("1..%d\n", nt);
        for (i = 0; i < nt; ++i) {
                if ((result = t[i].func()) != NULL)
                        printf("not ok %d - %s # %s\n", i + 1,
                            t[i].name, result);
                else
                        printf("ok %d - %s\n", i + 1,
                            t[i].name);
        }
        exit(0);
}