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 #ifndef HAVE_FCNTL
  31
  32 pid_t
  33 pid_output (const char *path)
  34 {
  35   FILE *fp;
  36   pid_t pid;
  37   mode_t oldumask;
  38
  39   pid = getpid();
  40
  41   oldumask = umask(0777 & ~PIDFILE_MASK);
  42   fp = fopen (path, "w");
  43   if (fp != NULL)
  44     {
  45       fprintf (fp, "%d\n", (int) pid);
  46       fclose (fp);
  47       umask(oldumask);
  48       return pid;
  49     }
  50   /* XXX Why do we continue instead of exiting?  This seems incompatible
  51      with the behavior of the fcntl version below. */
  52   zlog_warn("Can't fopen pid lock file %s (%s), continuing",
  53             path, safe_strerror(errno));
  54   umask(oldumask);
  55   return -1;
  56 }
  57
  58 #else /* HAVE_FCNTL */
  59
  60 pid_t
  61 pid_output (const char *path)
  62 {
  63   int tmp;
  64   int fd;
  65   pid_t pid;
  66   char buf[16];
  67   struct flock lock;
  68   mode_t oldumask;
  69
  70   pid = getpid ();
  71
  72   oldumask = umask(0777 & ~PIDFILE_MASK);
  73   fd = open (path, O_RDWR | O_CREAT, PIDFILE_MASK);
  74   if (fd < 0)
  75     {
  76       zlog_err("Can't create pid lock file %s (%s), exiting",
  77                path, safe_strerror(errno));
  78       umask(oldumask);
  79       exit(1);
  80     }
  81   else
  82     {
  83       size_t pidsize;
  84
  85       umask(oldumask);
  86       memset (&lock, 0, sizeof(lock));
  87
  88       set_cloexec(fd);
  89
  90       lock.l_type = F_WRLCK;
  91       lock.l_whence = SEEK_SET;
  92
  93       if (fcntl(fd, F_SETLK, &lock) < 0)
  94         {
  95           zlog_err("Could not lock pid_file %s, exiting", path);
  96           exit(1);
  97         }
  98
  99       sprintf (buf, "%d\n", (int) pid);
 100       pidsize = strlen(buf);
 101       if ((tmp = write (fd, buf, pidsize)) != (int)pidsize)
 102         zlog_err("Could not write pid %d to pid_file %s, rc was %d: %s",
 103                  (int)pid,path,tmp,safe_strerror(errno));
 104       else if (ftruncate(fd, pidsize) < 0)
 105         zlog_err("Could not truncate pid_file %s to %u bytes: %s",
 106                  path,(u_int)pidsize,safe_strerror(errno));
 107     }
 108   return pid;
 109 }
 110
 111 #endif /* HAVE_FCNTL */