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 pid_output(const char *path)
  31 {
  32         int tmp;
  33         int fd;
  34         pid_t pid;
  35         char buf[16];
  36         struct flock lock;
  37         mode_t oldumask;
  38
  39         pid = getpid();
  40
  41         oldumask = umask(0777 & ~PIDFILE_MASK);
  42         fd = open(path, O_RDWR | O_CREAT, PIDFILE_MASK);
  43         if (fd < 0) {
  44                 zlog_err("Can't create pid lock file %s (%s), exiting", path,
  45                          safe_strerror(errno));
  46                 umask(oldumask);
  47                 exit(1);
  48         } else {
  49                 size_t pidsize;
  50
  51                 umask(oldumask);
  52                 memset(&lock, 0, sizeof(lock));
  53
  54                 set_cloexec(fd);
  55
  56                 lock.l_type = F_WRLCK;
  57                 lock.l_whence = SEEK_SET;
  58
  59                 if (fcntl(fd, F_SETLK, &lock) < 0) {
  60                         zlog_err("Could not lock pid_file %s (%s), exiting",
  61                                  path, safe_strerror(errno));
  62                         exit(1);
  63                 }
  64
  65                 sprintf(buf, "%d\n", (int)pid);
  66                 pidsize = strlen(buf);
  67                 if ((tmp = write(fd, buf, pidsize)) != (int)pidsize)
  68                         zlog_err(
  69                                 "Could not write pid %d to pid_file %s, rc was %d: %s",
  70                                 (int)pid, path, tmp, safe_strerror(errno));
  71                 else if (ftruncate(fd, pidsize) < 0)
  72                         zlog_err(
  73                                 "Could not truncate pid_file %s to %u bytes: %s",
  74                                 path, (u_int)pidsize, safe_strerror(errno));
  75         }
  76         return pid;
  77 }