LXR busybox/console-tools/setconsole.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * setconsole.c - redirect system console output
   4 *
   5 * Copyright (C) 2004,2005  Enrik Berkhan <Enrik.Berkhan@inka.de>
   6 * Copyright (C) 2008 Bernhard Reutner-Fischer
   7 *
   8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9 */
  10//config:config SETCONSOLE
  11//config:       bool "setconsole (3.6 kb)"
  12//config:       default y
  13//config:       select PLATFORM_LINUX
  14//config:       help
  15//config:       Redirect writes to /dev/console to another device,
  16//config:       like the current tty while logged in via telnet.
  17//config:       This does not redirect kernel log, only writes
  18//config:       from user space.
  19//config:
  20//config:config FEATURE_SETCONSOLE_LONG_OPTIONS
  21//config:       bool "Enable long options"
  22//config:       default y
  23//config:       depends on SETCONSOLE && LONG_OPTS
  24
  25//applet:IF_SETCONSOLE(APPLET_NOEXEC(setconsole, setconsole, BB_DIR_SBIN, BB_SUID_DROP, setconsole))
  26
  27//kbuild:lib-$(CONFIG_SETCONSOLE) += setconsole.o
  28
  29//usage:#define setconsole_trivial_usage
  30//usage:       "[-r] [DEVICE]"
  31//usage:#define setconsole_full_usage "\n\n"
  32//usage:       "Make writes to /dev/console appear on DEVICE (default: /dev/tty)."
  33//usage:   "\n""Does not redirect kernel log output or reads from /dev/console."
  34//usage:   "\n"
  35//usage:   "\n""        -r      Reset: writes to /dev/console go to kernel log tty(s)"
  36
  37/* It was a bbox-specific invention, but SUSE does have a similar utility.
  38 * SUSE has no -r option, though.
  39 */
  40
  41#include "libbb.h"
  42
  43int setconsole_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  44int setconsole_main(int argc UNUSED_PARAM, char **argv)
  45{
  46        const char *device = CURRENT_TTY;
  47        int reset;
  48
  49        /* at most one non-option argument */
  50        reset = getopt32(argv, "^" "r" "\0" "?1");
  51
  52        argv += 1 + reset;
  53        if (*argv) {
  54                device = *argv;
  55        } else {
  56                if (reset)
  57                        device = DEV_CONSOLE;
  58        }
  59
  60//TODO: fails if TIOCCONS redir is already active to some tty.
  61//I think SUSE version first does TIOCCONS on /dev/console fd (iow: resets)
  62//then TIOCCONS to new tty?
  63        xioctl(xopen(device, O_WRONLY), TIOCCONS, NULL);
  64        return EXIT_SUCCESS;
  65}
  66