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
  28 #define PIDFILE_MASK 0644
  29 #ifndef HAVE_FCNTL
  30
  31 pid_t
  32 pid_output (const char *path)
  33 {
  34   FILE *fp;
  35   pid_t pid;
  36   mode_t oldumask;
  37
  38   pid = getpid();
  39
  40   oldumask = umask(0777 & ~PIDFILE_MASK);
  41   fp = fopen (path, "w");
  42   if (fp != NULL)
  43     {
  44       fprintf (fp, "%d\n", (int) pid);
  45       fclose (fp);
  46       umask(oldumask);
  47       return pid;
  48     }
  49   /* XXX Why do we continue instead of exiting?  This seems incompatible
  50      with the behavior of the fcntl version below. */
  51   zlog_warn("Can't fopen pid lock file %s (%s), continuing",
  52             path, safe_strerror(errno));
  53   umask(oldumask);
  54   return -1;
  55 }
  56
  57 #else /* HAVE_FCNTL */
  58
  59 pid_t
  60 pid_output (const char *path)
  61 {
  62   int tmp;
  63   int fd;
  64   pid_t pid;
  65   char buf[16];
  66   struct flock lock;
  67   mode_t oldumask;
  68
  69   pid = getpid ();
  70
  71   oldumask = umask(0777 & ~PIDFILE_MASK);
  72   fd = open (path, O_RDWR | O_CREAT, PIDFILE_MASK);
  73   if (fd < 0)
  74     {
  75       zlog_err("Can't create pid lock file %s (%s), exiting",
  76                path, safe_strerror(errno));
  77       umask(oldumask);
  78       exit(1);
  79     }
  80   else
  81     {
  82       size_t pidsize;
  83
  84       umask(oldumask);
  85       memset (&lock, 0, sizeof(lock));
  86
  87       lock.l_type = F_WRLCK;
  88       lock.l_whence = SEEK_SET;
  89
  90       if (fcntl(fd, F_SETLK, &lock) < 0)
  91         {
  92           zlog_err("Could not lock pid_file %s, exiting", path);
  93           exit(1);
  94         }
  95
  96       sprintf (buf, "%d\n", (int) pid);
  97       pidsize = strlen(buf);
  98       if ((tmp = write (fd, buf, pidsize)) != (int)pidsize)
  99         zlog_err("Could not write pid %d to pid_file %s, rc was %d: %s",
 100                  (int)pid,path,tmp,safe_strerror(errno));
 101       else if (ftruncate(fd, pidsize) < 0)
 102         zlog_err("Could not truncate pid_file %s to %u bytes: %s",
 103                  path,(u_int)pidsize,safe_strerror(errno));
 104     }
 105   return pid;
 106 }
 107
 108 #endif /* HAVE_FCNTL */