lib/pid_output.c

   1 /*
   2  * Process id output.
   3  * Copyright (C) 1998, 1999 Kunihiro Ishiguro
   4  *
   5  * This file is part of GNU Zebra.
   6  *
   7  * GNU Zebra is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2, or (at your option) any
  10  * later version.
  11  *
  12  * GNU Zebra is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  19  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20  * 02111-1307, USA.
  21  */
  22
  23 #include <zebra.h>
  24 #include <fcntl.h>
  25 #include <log.h>
  26 #include "version.h"
  27 #include "network.h"
  28
  29 #define PIDFILE_MASK 0644
  30
  31 pid_t
  32 pid_output (const char *path)
  33 {
  34   int tmp;
  35   int fd;
  36   pid_t pid;
  37   char buf[16];
  38   struct flock lock;
  39   mode_t oldumask;
  40
  41   pid = getpid ();
  42
  43   oldumask = umask(0777 & ~PIDFILE_MASK);
  44   fd = open (path, O_RDWR | O_CREAT, PIDFILE_MASK);
  45   if (fd < 0)
  46     {
  47       zlog_err("Can't create pid lock file %s (%s), exiting",
  48                path, safe_strerror(errno));
  49       umask(oldumask);
  50       exit(1);
  51     }
  52   else
  53     {
  54       size_t pidsize;
  55
  56       umask(oldumask);
  57       memset (&lock, 0, sizeof(lock));
  58
  59       set_cloexec(fd);
  60
  61       lock.l_type = F_WRLCK;
  62       lock.l_whence = SEEK_SET;
  63
  64       if (fcntl(fd, F_SETLK, &lock) < 0)
  65         {
  66           zlog_err("Could not lock pid_file %s, exiting", path);
  67           exit(1);
  68         }
  69
  70       sprintf (buf, "%d\n", (int) pid);
  71       pidsize = strlen(buf);
  72       if ((tmp = write (fd, buf, pidsize)) != (int)pidsize)
  73         zlog_err("Could not write pid %d to pid_file %s, rc was %d: %s",
  74                  (int)pid,path,tmp,safe_strerror(errno));
  75       else if (ftruncate(fd, pidsize) < 0)
  76         zlog_err("Could not truncate pid_file %s to %u bytes: %s",
  77                  path,(u_int)pidsize,safe_strerror(errno));
  78     }
  79   return pid;
  80 }