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/*
** Zabbix
** Copyright (C) 2001-2019 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 "common.h"
#include "pid.h"
#include "log.h"
#include "threads.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 (0 == zbx_stat(pidfile, &buf))
{
if (-1 == (fd = open(pidfile, O_WRONLY | O_APPEND)))
{
zbx_error("cannot open PID file [%s]: %s", pidfile, zbx_strerror(errno));
return FAIL;
}
if (-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)))
{
fcntl(fdpid, F_SETLK, &fl);
fcntl(fdpid, F_SETFD, FD_CLOEXEC);
}
/* 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)
{
struct flock fl;
fl.l_type = F_UNLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
fl.l_pid = zbx_get_thread_id();
/* unlock file */
if (-1 != fdpid)
fcntl(fdpid, F_SETLK, &fl);
/* close pid file */
zbx_fclose(fpid);
unlink(pidfile);
}
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