/* Copyright (C) 2007-2010 Open Information Security Foundation

 *

 * You can copy, redistribute or modify this Program under the terms of

 * the GNU General Public License version 2 as published by the Free

 * Software Foundation.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * version 2 along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

/**

 * \file

 *

 * \author Pablo Rincon Crespo <pablo.rincon.crespo@gmail.com>

 * \author Victor Julien <victor@inliniac.net>

 *

 * Utility code for dealing with a pidfile.

 * Adaptation of Steve Grubbs patch to our coding guidelines

 * (thanks for the patch Steve ;)

 */

#include "suricata-common.h"

#include "util-pidfile.h"

#include "util-debug.h"

/**

 * \brief Write a pid file (used at the startup)

 *        This commonly needed by the init scripts

 *

 * \param pointer to the name of the pid file to write (optarg)

 *

 * \retval 0 if succes

 * \retval -1 on failure

 */

int SCPidfileCreate(const char *pidfile)

{

    SCEnter();

    int pidfd = 0;

    char val[16];

    size_t len = snprintf(val, sizeof(val), "%"PRIuMAX"\n", (uintmax_t)getpid());

    if (len <= 0) {

        SCLogError("Pid error (%s)", strerror(errno));

        SCReturnInt(-1);

    }

    pidfd = open(pidfile, O_CREAT | O_TRUNC | O_NOFOLLOW | O_WRONLY, 0644);

    if (pidfd < 0) {

        SCLogError("unable to set pidfile '%s': %s", pidfile, strerror(errno));

        SCReturnInt(-1);

    }

    ssize_t r = write(pidfd, val, (unsigned int)len);

    if (r == -1) {

        SCLogError("unable to write pidfile: %s", strerror(errno));

        close(pidfd);

        SCReturnInt(-1);

    } else if ((size_t)r != len) {

        SCLogError("unable to write pidfile: wrote"

                   " %" PRIdMAX " of %" PRIuMAX " bytes.",

                (intmax_t)r, (uintmax_t)len);

        close(pidfd);

        SCReturnInt(-1);

    }

    close(pidfd);

    SCReturnInt(0);

}

/**

 * \brief Remove the pid file (used at the startup)

 *

 * \param pointer to the name of the pid file to write (optarg)

 */

void SCPidfileRemove(const char *pid_filename)

{

    if (pid_filename != NULL) {

        /* we ignore the result, the user may have removed the file already. */

        (void)unlink(pid_filename);

    }

}

/**

 * \brief Check the Suricata pid file (used at the startup)

 *

 * This commonly needed by the init scripts.

 *

 * This function will fail if the PID file exists, but tries to log a

 * meaningful message if appears Suricata is running, or if the PID

 * file appears to be stale.

 *

 * \param pointer to the name of the pid file to write (optarg)

 *

 * \retval 0 if succes

 * \retval -1 on failure

 */

int SCPidfileTestRunning(const char *pid_filename)

{

    /* Check if the existing process is still alive. */

    FILE *pf;

    pf = fopen(pid_filename, "r");

    if (pf == NULL) {

        if (access(pid_filename, F_OK) == 0) {

            SCLogError("pid file '%s' exists and can not be read. Aborting!", pid_filename);

            return -1;

        } else {

            return 0;

        }

    }

#ifndef OS_WIN32

    pid_t pidv;

    if (fscanf(pf, "%d", &pidv) == 1 && kill(pidv, 0) == 0) {

        SCLogError("pid file '%s' exists and Suricata appears to be running. "

                   "Aborting!",

                pid_filename);

    } else

#endif

    {

        SCLogError("pid file '%s' exists but appears stale. "

                   "Make sure Suricata is not running and then remove %s. "

                   "Aborting!",

                pid_filename, pid_filename);

    }

    fclose(pf);

    return -1;

}