src/lib/process/pidfile.c

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2021, The Tor Project, Inc. */
   4 /* See LICENSE for licensing information */
   5
   6 /**
   7  * \file pidfile.c
   8  * \brief Record this process's PID to disk.
   9  **/
  10
  11 #include "orconfig.h"
  12 #include "lib/process/pidfile.h"
  13
  14 #include "lib/log/log.h"
  15
  16 #ifdef HAVE_SYS_TYPES_H
  17 #include <sys/types.h>
  18 #endif
  19 #ifdef HAVE_UNISTD_H
  20 #include <unistd.h>
  21 #endif
  22
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26
  27 /** Write the current process ID, followed by NL, into <b>filename</b>.
  28  * Return 0 on success, -1 on failure.
  29  */
  30 int
  31 write_pidfile(const char *filename)
  32 {
  33   FILE *pidfile;
  34
  35   if ((pidfile = fopen(filename, "w")) == NULL) {
  36     log_warn(LD_FS, "Unable to open \"%s\" for writing: %s", filename,
  37              strerror(errno));
  38     return -1;
  39   } else {
  40 #ifdef _WIN32
  41     int pid = (int)_getpid();
  42 #else
  43     int pid = (int)getpid();
  44 #endif
  45     int rv = 0;
  46     if (fprintf(pidfile, "%d\n", pid) < 0)
  47       rv = -1;
  48     if (fclose(pidfile) < 0)
  49       rv = -1;
  50     return rv;
  51   }
  52 }