LXR busybox/libbb/pidfile.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * pid file routines
   4 *
   5 * Copyright (C) 2007 by Stephane Billiart <stephane.billiart@gmail.com>
   6 *
   7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   8 */
   9
  10/* Override ENABLE_FEATURE_PIDFILE */
  11#define WANT_PIDFILE 1
  12#include "libbb.h"
  13
  14smallint wrote_pidfile;
  15
  16void FAST_FUNC write_pidfile(const char *path)
  17{
  18        int pid_fd;
  19        char *end;
  20        char buf[sizeof(int)*3 + 2];
  21        struct stat sb;
  22
  23        if (!path)
  24                return;
  25        /* we will overwrite stale pidfile */
  26        pid_fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0666);
  27        if (pid_fd < 0)
  28                return;
  29
  30        /* path can be "/dev/null"! Test for such cases */
  31        wrote_pidfile = (fstat(pid_fd, &sb) == 0) && S_ISREG(sb.st_mode);
  32
  33        if (wrote_pidfile) {
  34                /* few bytes larger, but doesn't use stdio */
  35                end = utoa_to_buf(getpid(), buf, sizeof(buf));
  36                *end = '\n';
  37                full_write(pid_fd, buf, end - buf + 1);
  38        }
  39        close(pid_fd);
  40}
  41