From 51ca7761a3579f3c3f7e771b39019e6e248a5171 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 16 Jul 2010 17:16:40 +0200 Subject: cttyhack: move build system bits into cttyhack.c, no code changes Signed-off-by: Denys Vlasenko --- shell/cttyhack.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) (limited to 'shell/cttyhack.c') diff --git a/shell/cttyhack.c b/shell/cttyhack.c index 67736ad62..7af13fdfd 100644 --- a/shell/cttyhack.c +++ b/shell/cttyhack.c @@ -6,6 +6,58 @@ */ #include "libbb.h" +//applet:IF_CTTYHACK(APPLET(cttyhack, _BB_DIR_BIN, _BB_SUID_DROP)) + +//kbuild:lib-$(CONFIG_CTTYHACK) += cttyhack.o + +//config:config CTTYHACK +//config: bool "cttyhack" +//config: default y +//config: help +//config: One common problem reported on the mailing list is "can't access tty; +//config: job control turned off" error message which typically appears when +//config: one tries to use shell with stdin/stdout opened to /dev/console. +//config: This device is special - it cannot be a controlling tty. +//config: +//config: Proper solution is to use correct device instead of /dev/console. +//config: +//config: cttyhack provides "quick and dirty" solution to this problem. +//config: It analyzes stdin with various ioctls, trying to determine whether +//config: it is a /dev/ttyN or /dev/ttySN (virtual terminal or serial line). +//config: If it detects one, it closes stdin/out/err and reopens that device. +//config: Then it executes given program. Opening the device will make +//config: that device a controlling tty. This may require cttyhack +//config: to be a session leader. +//config: +//config: Example for /etc/inittab (for busybox init): +//config: +//config: ::respawn:/bin/cttyhack /bin/sh +//config: +//config: Starting an interactive shell from boot shell script: +//config: +//config: setsid cttyhack sh +//config: +//config: Giving controlling tty to shell running with PID 1: +//config: +//config: # exec cttyhack sh +//config: +//config: Without cttyhack, you need to know exact tty name, +//config: and do something like this: +//config: +//config: # exec setsid sh -c 'exec sh /dev/tty1 2>&1' +//config: + +//usage:#define cttyhack_trivial_usage +//usage: "PROG ARGS" +//usage:#define cttyhack_full_usage "\n\n" +//usage: "Give PROG a controlling tty if possible." +//usage: "\nExample for /etc/inittab (for busybox init):" +//usage: "\n ::respawn:/bin/cttyhack /bin/sh" +//usage: "\nGiving controlling tty to shell running with PID 1:" +//usage: "\n $ exec cttyhack sh" +//usage: "\nStarting interactive shell from boot shell script:" +//usage: "\n setsid cttyhack sh" + /* From */ struct vt_stat { unsigned short v_active; /* active vt */ -- cgit v1.2.3