Zabbix

/*

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program is free software: you can redistribute it and/or modify it under the terms of

** the GNU Affero General Public License as published by the Free Software Foundation, version 3.

**

** 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 Affero General Public License for more details.

**

** You should have received a copy of the GNU Affero General Public License along with this program.

** If not, see <https://www.gnu.org/licenses/>.

**/

​

#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)))

    {

        zbx_error("error in setting the status flag: %s", zbx_strerror(errno));

    }

​

    /* write pid to file */

    fprintf(fpid, "%d", (int)getpid());

    fflush(fpid);

​

    return SUCCEED;

}

​

int read_pid_file(const char *pidfile, pid_t *pid, char *error, size_t max_error_len)

{

    int ret = FAIL;

    FILE    *f_pid;

​

    if (NULL == (f_pid = fopen(pidfile, "r")))

    {

        zbx_snprintf(error, max_error_len, "cannot open PID file [%s]: %s", pidfile, zbx_strerror(errno));

        return ret;

    }

​

    if (1 == fscanf(f_pid, "%d", (int *)pid))

        ret = SUCCEED;

    else

        zbx_snprintf(error, max_error_len, "cannot retrieve PID from file [%s]", pidfile);

​

    zbx_fclose(f_pid);

​

    return ret;

}

​

void    drop_pid_file(const char *pidfile)