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 //config:config NOHUP
  13 //config:       bool "nohup (2 kb)"
  14 //config:       default y
  15 //config:       help
  16 //config:       run a command immune to hangups, with output to a non-tty.
  17
  18 //applet:IF_NOHUP(APPLET(nohup, BB_DIR_USR_BIN, BB_SUID_DROP))
  19
  20 //kbuild:lib-$(CONFIG_NOHUP) += nohup.o
  21
  22 //usage:#define nohup_trivial_usage
  23 //usage:       "PROG ARGS"
  24 //usage:#define nohup_full_usage "\n\n"
  25 //usage:       "Run PROG immune to hangups, with output to a non-tty"
  26 //usage:
  27 //usage:#define nohup_example_usage
  28 //usage:       "$ nohup make &"
  29
  30 #include "libbb.h"
  31
  32 /* Compat info: nohup (GNU coreutils 6.8) does this:
  33 # nohup true
  34 nohup: ignoring input and appending output to `nohup.out'
  35 # nohup true 1>/dev/null
  36 nohup: ignoring input and redirecting stderr to stdout
  37 # nohup true 2>zz
  38 # cat zz
  39 nohup: ignoring input and appending output to `nohup.out'
  40 # nohup true 2>zz 1>/dev/null
  41 # cat zz
  42 nohup: ignoring input
  43 # nohup true </dev/null 1>/dev/null
  44 nohup: redirecting stderr to stdout
  45 # nohup true </dev/null 2>zz 1>/dev/null
  46 # cat zz
  47   (nothing)
  48 #
  49 */
  50
  51 int nohup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  52 int nohup_main(int argc UNUSED_PARAM, char **argv)
  53 {
  54         const char *nohupout;
  55         char *home;
  56
  57         xfunc_error_retval = 127;
  58
  59         if (!argv[1]) {
  60                 bb_show_usage();
  61         }
  62
  63         /* If stdin is a tty, detach from it. */
  64         if (isatty(STDIN_FILENO)) {
  65                 /* bb_error_msg("ignoring input"); */
  66                 close(STDIN_FILENO);
  67                 xopen(bb_dev_null, O_RDONLY); /* will be fd 0 (STDIN_FILENO) */
  68         }
  69
  70         nohupout = "nohup.out";
  71         /* Redirect stdout to nohup.out, either in "." or in "$HOME". */
  72         if (isatty(STDOUT_FILENO)) {
  73                 close(STDOUT_FILENO);
  74                 if (open(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR) < 0) {
  75                         home = getenv("HOME");
  76                         if (home) {
  77                                 nohupout = concat_path_file(home, nohupout);
  78                                 xopen3(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR);
  79                         } else {
  80                                 xopen(bb_dev_null, O_RDONLY); /* will be fd 1 */
  81                         }
  82                 }
  83                 bb_error_msg("appending output to %s", nohupout);
  84         }
  85
  86         /* If we have a tty on stderr, redirect to stdout. */
  87         if (isatty(STDERR_FILENO)) {
  88                 /* if (stdout_wasnt_a_tty)
  89                         bb_error_msg("redirecting stderr to stdout"); */
  90                 dup2(STDOUT_FILENO, STDERR_FILENO);
  91         }
  92
  93         signal(SIGHUP, SIG_IGN);
  94
  95         argv++;
  96         BB_EXECVP_or_die(argv);
  97 }