From 3a9241add947cb6d24b5de7a8927517426a78795 Mon Sep 17 00:00:00 2001 From: Rob Landley Date: Sat, 25 Aug 2012 14:25:22 -0500 Subject: Move commands into "posix", "lsb", and "other" menus/directories. --- toys/other/oneit.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 80 insertions(+) create mode 100644 toys/other/oneit.c (limited to 'toys/other/oneit.c') diff --git a/toys/other/oneit.c b/toys/other/oneit.c new file mode 100644 index 00000000..45935918 --- /dev/null +++ b/toys/other/oneit.c @@ -0,0 +1,80 @@ +/* vi: set sw=4 ts=4: + * + * oneit.c, tiny one-process init replacement. + * + * Copyright 2005, 2007 by Rob Landley . + * + * Not in SUSv3. + +USE_ONEIT(NEWTOY(oneit, "^<1c:p", TOYFLAG_SBIN)) + +config ONEIT + bool "oneit" + default y + help + usage: oneit [-p] [-c /dev/tty0] command [...] + + A simple init program that runs a single supplied command line with a + controlling tty (so CTRL-C can kill it). + + -p Power off instead of rebooting when command exits. + -c Which console device to use. + + The oneit command runs the supplied command line as a child process + (because PID 1 has signals blocked), attached to /dev/tty0, in its + own session. Then oneit reaps zombies until the child exits, at + which point it reboots (or with -p, powers off) the system. +*/ + +#include "toys.h" +#include + +DEFINE_GLOBALS( + char *console; +) + +#define TT this.oneit + +// The minimum amount of work necessary to get ctrl-c and such to work is: +// +// - Fork a child (PID 1 is special: can't exit, has various signals blocked). +// - Do a setsid() (so we have our own session). +// - In the child, attach stdio to /dev/tty0 (/dev/console is special) +// - Exec the rest of the command line. +// +// PID 1 then reaps zombies until the child process it spawned exits, at which +// point it calls sync() and reboot(). I could stick a kill -1 in there. + + +void oneit_main(void) +{ + int i; + pid_t pid; + + // Create a new child process. + pid = vfork(); + if (pid) { + + // pid 1 just reaps zombies until it gets its child, then halts the system. + while (pid!=wait(&i)); + sync(); + + // PID 1 can't call reboot() because it kills the task that calls it, + // which causes the kernel to panic before the actual reboot happens. + if (!vfork()) reboot((toys.optflags&1) ? RB_POWER_OFF : RB_AUTOBOOT); + sleep(5); + _exit(1); + } + + // Redirect stdio to /dev/tty0, with new session ID, so ctrl-c works. + setsid(); + for (i=0; i<3; i++) { + close(i); + xopen(TT.console ? TT.console : "/dev/tty0",O_RDWR); + } + + // Can't xexec() here, because we vforked so we don't want to error_exit(). + toy_exec(toys.optargs); + execvp(*toys.optargs, toys.optargs); + _exit(127); +} -- cgit v1.2.3