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 along
  18  * with this program; see the file COPYING; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <zebra.h>
  23 #include <fcntl.h>
  24 #include <log.h>
  25 #include "version.h"
  26 #include "network.h"
  27
  28 #define PIDFILE_MASK 0644
  29
  30 pid_t
  31 pid_output (const char *path)
  32 {
  33   int tmp;
  34   int fd;
  35   pid_t pid;
  36   char buf[16];
  37   struct flock lock;
  38   mode_t oldumask;
  39
  40   pid = getpid ();
  41
  42   oldumask = umask(0777 & ~PIDFILE_MASK);
  43   fd = open (path, O_RDWR | O_CREAT, PIDFILE_MASK);
  44   if (fd < 0)
  45     {
  46       zlog_err("Can't create pid lock file %s (%s), exiting",
  47                path, safe_strerror(errno));
  48       umask(oldumask);
  49       exit(1);
  50     }
  51   else
  52     {
  53       size_t pidsize;
  54
  55       umask(oldumask);
  56       memset (&lock, 0, sizeof(lock));
  57
  58       set_cloexec(fd);
  59
  60       lock.l_type = F_WRLCK;
  61       lock.l_whence = SEEK_SET;
  62
  63       if (fcntl(fd, F_SETLK, &lock) < 0)
  64         {
  65           zlog_err("Could not lock pid_file %s, exiting", path);
  66           exit(1);
  67         }
  68
  69       sprintf (buf, "%d\n", (int) pid);
  70       pidsize = strlen(buf);
  71       if ((tmp = write (fd, buf, pidsize)) != (int)pidsize)
  72         zlog_err("Could not write pid %d to pid_file %s, rc was %d: %s",
  73                  (int)pid,path,tmp,safe_strerror(errno));
  74       else if (ftruncate(fd, pidsize) < 0)
  75         zlog_err("Could not truncate pid_file %s to %u bytes: %s",
  76                  path,(u_int)pidsize,safe_strerror(errno));
  77     }
  78   return pid;
  79 }