coreutils/nohup.c

   1 /* vi: set sw=4 ts=4: */
   2 /* nohup - invoke a utility immune to hangups.
   3  *
   4  * Busybox version based on nohup specification at
   5  * http://www.opengroup.org/onlinepubs/007904975/utilities/nohup.html
   6  *
   7  * Copyright 2006 Rob Landley <rob@landley.net>
   8  * Copyright 2006 Bernhard Reutner-Fischer
   9  *
  10  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  11  */
  12
  13 //usage:#define nohup_trivial_usage
  14 //usage:       "PROG ARGS"
  15 //usage:#define nohup_full_usage "\n\n"
  16 //usage:       "Run PROG immune to hangups, with output to a non-tty"
  17 //usage:
  18 //usage:#define nohup_example_usage
  19 //usage:       "$ nohup make &"
  20
  21 #include "libbb.h"
  22
  23 /* Compat info: nohup (GNU coreutils 6.8) does this:
  24 # nohup true
  25 nohup: ignoring input and appending output to `nohup.out'
  26 # nohup true 1>/dev/null
  27 nohup: ignoring input and redirecting stderr to stdout
  28 # nohup true 2>zz
  29 # cat zz
  30 nohup: ignoring input and appending output to `nohup.out'
  31 # nohup true 2>zz 1>/dev/null
  32 # cat zz
  33 nohup: ignoring input
  34 # nohup true </dev/null 1>/dev/null
  35 nohup: redirecting stderr to stdout
  36 # nohup true </dev/null 2>zz 1>/dev/null
  37 # cat zz
  38   (nothing)
  39 #
  40 */
  41
  42 int nohup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  43 int nohup_main(int argc UNUSED_PARAM, char **argv)
  44 {
  45         const char *nohupout;
  46         char *home;
  47
  48         xfunc_error_retval = 127;
  49
  50         if (!argv[1]) {
  51                 bb_show_usage();
  52         }
  53
  54         /* If stdin is a tty, detach from it. */
  55         if (isatty(STDIN_FILENO)) {
  56                 /* bb_error_msg("ignoring input"); */
  57                 close(STDIN_FILENO);
  58                 xopen(bb_dev_null, O_RDONLY); /* will be fd 0 (STDIN_FILENO) */
  59         }
  60
  61         nohupout = "nohup.out";
  62         /* Redirect stdout to nohup.out, either in "." or in "$HOME". */
  63         if (isatty(STDOUT_FILENO)) {
  64                 close(STDOUT_FILENO);
  65                 if (open(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR) < 0) {
  66                         home = getenv("HOME");
  67                         if (home) {
  68                                 nohupout = concat_path_file(home, nohupout);
  69                                 xopen3(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR);
  70                         } else {
  71                                 xopen(bb_dev_null, O_RDONLY); /* will be fd 1 */
  72                         }
  73                 }
  74                 bb_error_msg("appending output to %s", nohupout);
  75         }
  76
  77         /* If we have a tty on stderr, redirect to stdout. */
  78         if (isatty(STDERR_FILENO)) {
  79                 /* if (stdout_wasnt_a_tty)
  80                         bb_error_msg("redirecting stderr to stdout"); */
  81                 dup2(STDOUT_FILENO, STDERR_FILENO);
  82         }
  83
  84         signal(SIGHUP, SIG_IGN);
  85
  86         argv++;
  87         BB_EXECVP_or_die(argv);
  88 }