Zabbix

/*

** Zabbix

** Copyright (C) 2001-2023 Zabbix SIA

**

** This program is free software; you can redistribute it and/or modify

** it under the terms of the GNU General Public License as published by

** the Free Software Foundation; either version 2 of the License, or

** (at your option) any later version.

**

** 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

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

** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

**/

​

#include "zbxnix.h"

#include "pid.h"

​

#include "zbxcommon.h"

​

static FILE *fpid = NULL;

static int  fdpid = -1;

​

int create_pid_file(const char *pidfile)

{

    int     fd;

    zbx_stat_t  buf;

    struct flock    fl;

​

    fl.l_type = F_WRLCK;

    fl.l_whence = SEEK_SET;

    fl.l_start = 0;

    fl.l_len = 0;

    fl.l_pid = getpid();

​

    /* check if pid file already exists */

    if (-1 != (fd = open(pidfile, O_WRONLY | O_APPEND)))

    {

        if (0 == zbx_fstat(fd, &buf) && -1 == fcntl(fd, F_SETLK, &fl))

        {

            close(fd);

            zbx_error("Is this process already running? Could not lock PID file [%s]: %s",

                    pidfile, zbx_strerror(errno));

            return FAIL;

        }

​

        close(fd);

    }

​

    /* open pid file */

    if (NULL == (fpid = fopen(pidfile, "w")))

    {

        zbx_error("cannot create PID file [%s]: %s", pidfile, zbx_strerror(errno));

        return FAIL;

    }

​

    /* lock file */

    if (-1 != (fdpid = fileno(fpid)) && (-1 == fcntl(fdpid, F_SETLK, &fl) || -1 == fcntl(fdpid,

            F_SETFD, FD_CLOEXEC)))