blob: 0bc58724147cf3234eaa7b3cb6bb4aea0e6bb2a0 [file] [log] [blame]
/* vi: set sw=4 ts=4: */
* setconsole.c - redirect system console output
* Copyright (C) 2004,2005 Enrik Berkhan <>
* Copyright (C) 2008 Bernhard Reutner-Fischer
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
//config:config SETCONSOLE
//config: bool "setconsole (3.6 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: Redirect writes to /dev/console to another device,
//config: like the current tty while logged in via telnet.
//config: This does not redirect kernel log, only writes
//config: from user space.
//config: bool "Enable long options"
//config: default y
//config: depends on SETCONSOLE && LONG_OPTS
//applet:IF_SETCONSOLE(APPLET_NOEXEC(setconsole, setconsole, BB_DIR_SBIN, BB_SUID_DROP, setconsole))
//kbuild:lib-$(CONFIG_SETCONSOLE) += setconsole.o
//usage:#define setconsole_trivial_usage
//usage: "[-r] [DEVICE]"
//usage:#define setconsole_full_usage "\n\n"
//usage: "Make writes to /dev/console appear on DEVICE (default: /dev/tty)."
//usage: "\n""Does not redirect kernel log output or reads from /dev/console."
//usage: "\n"
//usage: "\n"" -r Reset: writes to /dev/console go to kernel log tty(s)"
/* It was a bbox-specific invention, but SUSE does have a similar utility.
* SUSE has no -r option, though.
#include "libbb.h"
int setconsole_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int setconsole_main(int argc UNUSED_PARAM, char **argv)
const char *device = CURRENT_TTY;
int reset;
/* at most one non-option argument */
reset = getopt32(argv, "^" "r" "\0" "?1");
argv += 1 + reset;
if (*argv) {
device = *argv;
} else {
if (reset)
device = DEV_CONSOLE;
//TODO: fails if TIOCCONS redir is already active to some tty.
//I think SUSE version first does TIOCCONS on /dev/console fd (iow: resets)
//then TIOCCONS to new tty?
xioctl(xopen(device, O_WRONLY), TIOCCONS, NULL);