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/* Copyright (c) 2009, 2011 Thorsten Kukuk
Author: Thorsten Kukuk <kukuk@suse.de>
The YP Server 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.
The YP Server 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 the YP Server; see the file COPYING. If
not, write to the Free Software Foundation, Inc., 51 Franklin Street,
Suite 500, Boston, MA 02110-1335, USA. */
#include "pidfile.h"
#include "log_msg.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <fcntl.h>
void
create_pidfile (const char *filename, const char *daemonname)
{
int fd, left, written;
pid_t pid;
char pbuf[50], *ptr;
struct flock lock;
fd = open (filename, O_CREAT | O_RDWR | O_CLOEXEC,
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (fd < 0)
{
log_msg ("cannot create pidfile %s", filename);
if (debug_flag)
log_msg ("\n");
exit (1);
}
lock.l_type = F_WRLCK;
lock.l_start = 0;
lock.l_whence = SEEK_SET;
lock.l_len = 0;
/* Is the pidfile locked by another daemon ? */
if (fcntl (fd, F_GETLK, &lock) < 0)
{
log_msg ("fcntl error");
if (debug_flag)
log_msg ("\n");
exit (1);
}
if (lock.l_type == F_UNLCK)
pid = 0; /* false, region is not locked by another proc */
else
pid = lock.l_pid; /* true, return pid of lock owner */
if (0 != pid)
{
log_msg ("%s already running (pid %d) - exiting", daemonname, pid);
if (debug_flag)
log_msg ("\n");
exit (1);
}
/* write lock */
lock.l_type = F_WRLCK;
lock.l_start = 0;
lock.l_whence = SEEK_SET;
lock.l_len = 0;
if (0 != fcntl (fd, F_SETLK, &lock))
log_msg ("cannot lock pidfile");
sprintf (pbuf, "%ld\n", (long) getpid ());
left = strlen (pbuf);
ptr = pbuf;
while (left > 0)
{
if ((written = write (fd, ptr, left)) <= 0)
return; /* error */
left -= written;
ptr += written;
}
return;
}
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