LXR busybox/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 tarball for details.
  11 */
  12
  13#include "libbb.h"
  14
  15/* Compat info: nohup (GNU coreutils 6.8) does this:
  16# nohup true
  17nohup: ignoring input and appending output to `nohup.out'
  18# nohup true 1>/dev/null
  19nohup: ignoring input and redirecting stderr to stdout
  20# nohup true 2>zz
  21# cat zz
  22nohup: ignoring input and appending output to `nohup.out'
  23# nohup true 2>zz 1>/dev/null
  24# cat zz
  25nohup: ignoring input
  26# nohup true </dev/null 1>/dev/null
  27nohup: redirecting stderr to stdout
  28# nohup true </dev/null 2>zz 1>/dev/null
  29# cat zz
  30  (nothing)
  31#
  32*/
  33
  34int nohup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  35int nohup_main(int argc UNUSED_PARAM, char **argv)
  36{
  37        const char *nohupout;
  38        char *home;
  39
  40        xfunc_error_retval = 127;
  41
  42        if (!argv[1]) {
  43                bb_show_usage();
  44        }
  45
  46        /* If stdin is a tty, detach from it. */
  47        if (isatty(STDIN_FILENO)) {
  48                /* bb_error_msg("ignoring input"); */
  49                close(STDIN_FILENO);
  50                xopen(bb_dev_null, O_RDONLY); /* will be fd 0 (STDIN_FILENO) */
  51        }
  52
  53        nohupout = "nohup.out";
  54        /* Redirect stdout to nohup.out, either in "." or in "$HOME". */
  55        if (isatty(STDOUT_FILENO)) {
  56                close(STDOUT_FILENO);
  57                if (open(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR) < 0) {
  58                        home = getenv("HOME");
  59                        if (home) {
  60                                nohupout = concat_path_file(home, nohupout);
  61                                xopen3(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR);
  62                        } else {
  63                                xopen(bb_dev_null, O_RDONLY); /* will be fd 1 */
  64                        }
  65                }
  66                bb_error_msg("appending output to %s", nohupout);
  67        }
  68
  69        /* If we have a tty on stderr, redirect to stdout. */
  70        if (isatty(STDERR_FILENO)) {
  71                /* if (stdout_wasnt_a_tty)
  72                        bb_error_msg("redirecting stderr to stdout"); */
  73                dup2(STDOUT_FILENO, STDERR_FILENO);
  74        }
  75
  76        signal(SIGHUP, SIG_IGN);
  77
  78        argv++;
  79        BB_EXECVP_or_die(argv);
  80}
  81