blob: cac165fc776bb2d9fafcba49835e2c936a4f91a4 [file] [log] [blame]
Erik Andersenccc74882000-01-27 02:40:21 +00001/* vi: set sw=4 ts=4: */
Eric Andersenc4996011999-10-20 22:08:37 +00002/*
3 * Mini init implementation for busybox
4 *
Eric Andersenc4996011999-10-20 22:08:37 +00005 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
Eric Andersenc7bda1c2004-03-15 08:29:22 +00006 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
Eric Andersenc4996011999-10-20 22:08:37 +00007 * Adjusted by so many folks, it's impossible to keep track.
8 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02009 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
Eric Andersenc4996011999-10-20 22:08:37 +000010 */
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020011//config:config INIT
Denys Vlasenko4eed2c62017-07-18 22:01:24 +020012//config: bool "init (9.3 kb)"
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020013//config: default y
14//config: select FEATURE_SYSLOG
15//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020016//config: init is the first program run when the system boots.
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020017//config:
Denys Vlasenko52977a72016-03-31 00:42:57 +020018//config:config LINUXRC
Denys Vlasenkof35ad3b2017-01-10 15:24:13 +010019//config: bool "linuxrc: support running init from initrd (not initramfs)"
Denys Vlasenko52977a72016-03-31 00:42:57 +020020//config: default y
21//config: select FEATURE_SYSLOG
22//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020023//config: Legacy support for running init under the old-style initrd. Allows
24//config: the name linuxrc to act as init, and it doesn't assume init is PID 1.
Denys Vlasenko52977a72016-03-31 00:42:57 +020025//config:
Denys Vlasenko72089cf2017-07-21 09:50:55 +020026//config: This does not apply to initramfs, which runs /init as PID 1 and
27//config: requires no special support.
Denys Vlasenko52977a72016-03-31 00:42:57 +020028//config:
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020029//config:config FEATURE_USE_INITTAB
30//config: bool "Support reading an inittab file"
31//config: default y
Denys Vlasenko52977a72016-03-31 00:42:57 +020032//config: depends on INIT || LINUXRC
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020033//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020034//config: Allow init to read an inittab file when the system boot.
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020035//config:
36//config:config FEATURE_KILL_REMOVED
37//config: bool "Support killing processes that have been removed from inittab"
38//config: default n
39//config: depends on FEATURE_USE_INITTAB
40//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020041//config: When respawn entries are removed from inittab and a SIGHUP is
42//config: sent to init, this option will make init kill the processes
43//config: that have been removed.
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020044//config:
45//config:config FEATURE_KILL_DELAY
46//config: int "How long to wait between TERM and KILL (0 - send TERM only)" if FEATURE_KILL_REMOVED
47//config: range 0 1024
48//config: default 0
49//config: depends on FEATURE_KILL_REMOVED
50//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020051//config: With nonzero setting, init sends TERM, forks, child waits N
52//config: seconds, sends KILL and exits. Setting it too high is unwise
53//config: (child will hang around for too long and could actually kill
54//config: the wrong process!)
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020055//config:
56//config:config FEATURE_INIT_SCTTY
57//config: bool "Run commands with leading dash with controlling tty"
58//config: default y
Denys Vlasenko52977a72016-03-31 00:42:57 +020059//config: depends on INIT || LINUXRC
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020060//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020061//config: If this option is enabled, init will try to give a controlling
62//config: tty to any command which has leading hyphen (often it's "-/bin/sh").
63//config: More precisely, init will do "ioctl(STDIN_FILENO, TIOCSCTTY, 0)".
64//config: If device attached to STDIN_FILENO can be a ctty but is not yet
65//config: a ctty for other session, it will become this process' ctty.
66//config: This is not the traditional init behavour, but is often what you want
67//config: in an embedded system where the console is only accessed during
68//config: development or for maintenance.
69//config: NB: using cttyhack applet may work better.
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020070//config:
71//config:config FEATURE_INIT_SYSLOG
72//config: bool "Enable init to write to syslog"
73//config: default y
Denys Vlasenko52977a72016-03-31 00:42:57 +020074//config: depends on INIT || LINUXRC
Denys Vlasenko42776702017-04-07 19:13:09 +020075//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020076//config: If selected, some init messages are sent to syslog.
77//config: Otherwise, they are sent to VT #5 if linux virtual tty is detected
78//config: (if not, no separate logging is done).
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020079//config:
Denys Vlasenkof35ad3b2017-01-10 15:24:13 +010080//config:config FEATURE_INIT_QUIET
81//config: bool "Be quiet on boot (no 'init started:' message)"
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020082//config: default y
Denys Vlasenko52977a72016-03-31 00:42:57 +020083//config: depends on INIT || LINUXRC
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020084//config:
85//config:config FEATURE_INIT_COREDUMPS
86//config: bool "Support dumping core for child processes (debugging only)"
Denys Vlasenko326edc32016-12-22 14:36:49 +010087//config: default n # not Y because this is a debug option
Denys Vlasenko52977a72016-03-31 00:42:57 +020088//config: depends on INIT || LINUXRC
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020089//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020090//config: If this option is enabled and the file /.init_enable_core
91//config: exists, then init will call setrlimit() to allow unlimited
92//config: core file sizes. If this option is disabled, processes
93//config: will not generate any core files.
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020094//config:
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020095//config:config INIT_TERMINAL_TYPE
96//config: string "Initial terminal type"
97//config: default "linux"
Denys Vlasenko52977a72016-03-31 00:42:57 +020098//config: depends on INIT || LINUXRC
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020099//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +0200100//config: This is the initial value set by init for the TERM environment
101//config: variable. This variable is used by programs which make use of
102//config: extended terminal capabilities.
Denys Vlasenkob1db09b2010-10-12 13:47:15 +0200103//config:
Denys Vlasenko72089cf2017-07-21 09:50:55 +0200104//config: Note that on Linux, init attempts to detect serial terminal and
105//config: sets TERM to "vt102" if one is found.
Nicolas Carrier29eae722016-02-04 12:18:01 +0100106//config:
107//config:config FEATURE_INIT_MODIFY_CMDLINE
Denys Vlasenkof5604222017-01-10 14:58:54 +0100108//config: bool "Clear init's command line"
Nicolas Carrier29eae722016-02-04 12:18:01 +0100109//config: default y
Denys Vlasenko52977a72016-03-31 00:42:57 +0200110//config: depends on INIT || LINUXRC
Nicolas Carrier29eae722016-02-04 12:18:01 +0100111//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +0200112//config: When launched as PID 1 and after parsing its arguments, init
113//config: wipes all the arguments but argv[0] and rewrites argv[0] to
114//config: contain only "init", so that its command line appears solely as
115//config: "init" in tools such as ps.
116//config: If this option is set to Y, init will keep its original behavior,
117//config: otherwise, all the arguments including argv[0] will be preserved,
118//config: be they parsed or ignored by init.
119//config: The original command-line used to launch init can then be
120//config: retrieved in /proc/1/cmdline on Linux, for example.
Denys Vlasenkob1db09b2010-10-12 13:47:15 +0200121
Denys Vlasenko730e4d82013-10-12 04:52:22 +0200122//applet:IF_INIT(APPLET(init, BB_DIR_SBIN, BB_SUID_DROP))
Denys Vlasenko52977a72016-03-31 00:42:57 +0200123//applet:IF_LINUXRC(APPLET_ODDNAME(linuxrc, init, BB_DIR_ROOT, BB_SUID_DROP, linuxrc))
Denys Vlasenko730e4d82013-10-12 04:52:22 +0200124
125//kbuild:lib-$(CONFIG_INIT) += init.o
Denys Vlasenko52977a72016-03-31 00:42:57 +0200126//kbuild:lib-$(CONFIG_LINUXRC) += init.o
Denys Vlasenko730e4d82013-10-12 04:52:22 +0200127
Denys Vlasenkoda2b2da2012-01-30 12:15:22 +0100128#define DEBUG_SEGV_HANDLER 0
129
Denis Vlasenkob6adbf12007-05-26 19:00:18 +0000130#include "libbb.h"
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100131#include "common_bufsiz.h"
Bernhard Reutner-Fischerf4701962008-01-27 12:50:12 +0000132#include <syslog.h>
Denis Vlasenko6c622462009-01-29 02:01:04 +0000133#include <sys/resource.h>
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200134#ifdef __linux__
Denys Vlasenko67905e22011-07-26 13:42:12 +0200135# include <linux/vt.h>
136# include <sys/sysinfo.h>
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200137#endif
Jeremie Koenig714674e2010-05-27 15:38:44 +0200138#include "reboot.h" /* reboot() constants */
Eric Andersen2c1de612003-04-24 11:41:28 +0000139
Denys Vlasenkoda2b2da2012-01-30 12:15:22 +0100140#if DEBUG_SEGV_HANDLER
141# undef _GNU_SOURCE
142# define _GNU_SOURCE 1
143# undef __USE_GNU
144# define __USE_GNU 1
145# include <execinfo.h>
146# include <sys/ucontext.h>
147#endif
148
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200149/* Used only for sanitizing purposes in set_sane_term() below. On systems where
150 * the baud rate is stored in a separate field, we can safely disable them. */
151#ifndef CBAUD
152# define CBAUD 0
153# define CBAUDEX 0
154#endif
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000155
Denis Vlasenko5cb54b52008-10-21 17:14:26 +0000156/* Was a CONFIG_xxx option. A lot of people were building
157 * not fully functional init by switching it on! */
158#define DEBUG_INIT 0
159
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000160#define CONSOLE_NAME_SIZE 32
Eric Andersenbd22ed82000-07-08 18:55:24 +0000161
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000162/* Default sysinit script. */
Erik Andersen96e2abd2000-01-07 11:40:44 +0000163#ifndef INIT_SCRIPT
Denys Vlasenkof9584252013-05-21 16:36:51 +0200164# define INIT_SCRIPT "/etc/init.d/rcS"
Erik Andersen96e2abd2000-01-07 11:40:44 +0000165#endif
Erik Andersen9c88cac1999-12-30 09:25:17 +0000166
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000167/* Each type of actions can appear many times. They will be
168 * handled in order. RESTART is an exception, only 1st is used.
169 */
170/* Start these actions first and wait for completion */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000171#define SYSINIT 0x01
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000172/* Start these after SYSINIT and wait for completion */
173#define WAIT 0x02
174/* Start these after WAIT and *dont* wait for completion */
175#define ONCE 0x04
176/*
177 * NB: while SYSINIT/WAIT/ONCE are being processed,
Denys Vlasenko6e542492009-11-15 03:07:19 +0100178 * SIGHUP ("reread /etc/inittab") will be processed only after
179 * each group of actions. If new inittab adds, say, a SYSINIT action,
180 * it will not be run, since init is already "past SYSINIT stage".
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000181 */
182/* Start these after ONCE are started, restart on exit */
183#define RESPAWN 0x08
184/* Like RESPAWN, but wait for <Enter> to be pressed on tty */
185#define ASKFIRST 0x10
186/*
187 * Start these on SIGINT, and wait for completion.
188 * Then go back to respawning RESPAWN and ASKFIRST actions.
189 * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
190 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000191#define CTRLALTDEL 0x20
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000192/*
193 * Start these before killing all processes in preparation for
194 * running RESTART actions or doing low-level halt/reboot/poweroff
195 * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
196 * Wait for completion before proceeding.
197 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000198#define SHUTDOWN 0x40
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000199/*
200 * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
201 * then all processes are killed, then init exec's 1st RESTART action,
202 * replacing itself by it. If no RESTART action specified,
203 * SIGQUIT has no effect.
204 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000205#define RESTART 0x80
Erik Andersen7dc16072000-01-04 01:10:25 +0000206
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000207/* A linked list of init_actions, to be read from inittab */
Eric Andersen0298be82002-03-05 15:12:19 +0000208struct init_action {
Eric Andersen0298be82002-03-05 15:12:19 +0000209 struct init_action *next;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000210 pid_t pid;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000211 uint8_t action_type;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000212 char terminal[CONSOLE_NAME_SIZE];
Denys Vlasenkod2e07bc2013-08-16 11:48:48 +0200213 char command[1];
Erik Andersen7dc16072000-01-04 01:10:25 +0000214};
Erik Andersen7dc16072000-01-04 01:10:25 +0000215
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100216struct globals {
217 struct init_action *init_action_list;
Denys Vlasenko42776702017-04-07 19:13:09 +0200218#if !ENABLE_FEATURE_INIT_SYSLOG
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100219 const char *log_console;
Denys Vlasenko42776702017-04-07 19:13:09 +0200220#endif
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100221} FIX_ALIASING;
222#define G (*(struct globals*)bb_common_bufsiz1)
223#define INIT_G() do { \
224 setup_common_bufsiz(); \
225 IF_NOT_FEATURE_INIT_SYSLOG(G.log_console = VC_5;) \
226} while (0)
Rob Landleybc68cd12006-03-10 19:22:06 +0000227
228enum {
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000229 L_LOG = 0x1,
230 L_CONSOLE = 0x2,
Rob Landleybc68cd12006-03-10 19:22:06 +0000231};
Erik Andersen42094cd2000-03-20 21:34:52 +0000232
Erik Andersen42094cd2000-03-20 21:34:52 +0000233/* Print a message to the specified device.
Denis Vlasenko671ca332008-02-19 14:13:20 +0000234 * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
235 * NB: careful, we can be called after vfork!
236 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000237#define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
Denis Vlasenko671ca332008-02-19 14:13:20 +0000238static void message(int where, const char *fmt, ...)
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000239 __attribute__ ((format(printf, 2, 3)));
Denis Vlasenko671ca332008-02-19 14:13:20 +0000240static void message(int where, const char *fmt, ...)
Eric Andersen0460ff21999-10-25 23:32:44 +0000241{
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000242 va_list arguments;
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000243 unsigned l;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000244 char msg[128];
245
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000246 msg[0] = '\r';
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000247 va_start(arguments, fmt);
Denis Vlasenko1bcdcd22008-12-09 21:23:31 +0000248 l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
Yuan-Hsiang Leeb21bc802013-11-03 00:13:16 +0100249 if (l > sizeof(msg) - 2)
250 l = sizeof(msg) - 2;
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000251 va_end(arguments);
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000252
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000253#if ENABLE_FEATURE_INIT_SYSLOG
254 msg[l] = '\0';
255 if (where & L_LOG) {
256 /* Log the message to syslogd */
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100257 openlog(applet_name, 0, LOG_DAEMON);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000258 /* don't print "\r" */
259 syslog(LOG_INFO, "%s", msg + 1);
260 closelog();
261 }
262 msg[l++] = '\n';
263 msg[l] = '\0';
264#else
Denys Vlasenko42776702017-04-07 19:13:09 +0200265 msg[l++] = '\n';
266 msg[l] = '\0';
267 if (where & L_LOG) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000268 /* Take full control of the log tty, and never close it.
269 * It's mine, all mine! Muhahahaha! */
Denys Vlasenko42776702017-04-07 19:13:09 +0200270 static int log_fd = -1;
271
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000272 if (log_fd < 0) {
Denys Vlasenko42776702017-04-07 19:13:09 +0200273 log_fd = STDERR_FILENO;
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100274 if (G.log_console) {
275 log_fd = device_open(G.log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000276 if (log_fd < 0) {
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100277 bb_error_msg("can't log to %s", G.log_console);
Denis Vlasenko671ca332008-02-19 14:13:20 +0000278 where = L_CONSOLE;
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000279 } else {
280 close_on_exec_on(log_fd);
281 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000282 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000283 }
Denys Vlasenko42776702017-04-07 19:13:09 +0200284 full_write(log_fd, msg, l);
285 if (log_fd == STDERR_FILENO)
286 return; /* don't print dup messages */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000287 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000288#endif
Eric Andersen4c781471999-11-26 08:12:56 +0000289
Denis Vlasenko671ca332008-02-19 14:13:20 +0000290 if (where & L_CONSOLE) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000291 /* Send console messages to console so people will see them. */
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000292 full_write(STDERR_FILENO, msg, l);
Eric Andersen3ae0c781999-11-04 01:13:21 +0000293 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000294}
295
Eric Andersen74400cc2001-10-18 04:11:39 +0000296static void console_init(void)
Eric Andersen0460ff21999-10-25 23:32:44 +0000297{
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200298#ifdef VT_OPENQRY
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000299 int vtno;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200300#endif
Erik Andersene49d5ec2000-02-08 19:58:47 +0000301 char *s;
Eric Andersen0460ff21999-10-25 23:32:44 +0000302
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000303 s = getenv("CONSOLE");
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000304 if (!s)
305 s = getenv("console");
Denys Vlasenkod0355282016-08-22 20:56:58 +0200306#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
307 /* BSD people say their kernels do not open fd 0,1,2; they need this: */
308 if (!s)
309 s = (char*)"/dev/console";
310#endif
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000311 if (s) {
312 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
313 if (fd >= 0) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000314 dup2(fd, STDIN_FILENO);
315 dup2(fd, STDOUT_FILENO);
316 xmove_fd(fd, STDERR_FILENO);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000317 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000318 dbg_message(L_LOG, "console='%s'", s);
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000319 } else {
Denis Vlasenkofb274df2008-03-17 13:26:51 +0000320 /* Make sure fd 0,1,2 are not closed
321 * (so that they won't be used by future opens) */
Denis Vlasenkod48e81f2008-07-06 07:00:11 +0000322 bb_sanitize_stdio();
Denis Vlasenkoa34b8a42008-11-29 23:14:37 +0000323// Users report problems
324// /* Make sure init can't be blocked by writing to stderr */
325// fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
Eric Andersen07e52971999-11-07 07:38:08 +0000326 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000327
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000328 s = getenv("TERM");
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200329#ifdef VT_OPENQRY
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000330 if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) {
331 /* Not a linux terminal, probably serial console.
332 * Force the TERM setting to vt102
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000333 * if TERM is set to linux (the default) */
334 if (!s || strcmp(s, "linux") == 0)
335 putenv((char*)"TERM=vt102");
Denys Vlasenko42776702017-04-07 19:13:09 +0200336# if !ENABLE_FEATURE_INIT_SYSLOG
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100337 G.log_console = NULL;
Denys Vlasenko42776702017-04-07 19:13:09 +0200338# endif
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200339 } else
340#endif
341 if (!s)
Jeremie Koenig1c053032010-05-27 15:46:07 +0200342 putenv((char*)"TERM=" CONFIG_INIT_TERMINAL_TYPE);
Eric Andersen0460ff21999-10-25 23:32:44 +0000343}
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000344
Denis Vlasenko671ca332008-02-19 14:13:20 +0000345/* Set terminal settings to reasonable defaults.
346 * NB: careful, we can be called after vfork! */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000347static void set_sane_term(void)
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000348{
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000349 struct termios tty;
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000350
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000351 tcgetattr(STDIN_FILENO, &tty);
352
353 /* set control chars */
354 tty.c_cc[VINTR] = 3; /* C-c */
355 tty.c_cc[VQUIT] = 28; /* C-\ */
356 tty.c_cc[VERASE] = 127; /* C-? */
357 tty.c_cc[VKILL] = 21; /* C-u */
358 tty.c_cc[VEOF] = 4; /* C-d */
359 tty.c_cc[VSTART] = 17; /* C-q */
360 tty.c_cc[VSTOP] = 19; /* C-s */
361 tty.c_cc[VSUSP] = 26; /* C-z */
362
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200363#ifdef __linux__
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000364 /* use line discipline 0 */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000365 tty.c_line = 0;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200366#endif
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000367
368 /* Make it be sane */
Denys Vlasenkof2657a92010-10-24 02:04:10 +0200369#ifndef CRTSCTS
370# define CRTSCTS 0
371#endif
372 /* added CRTSCTS to fix Debian bug 528560 */
373 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD | CRTSCTS;
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000374 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
375
376 /* input modes */
377 tty.c_iflag = ICRNL | IXON | IXOFF;
378
379 /* output modes */
380 tty.c_oflag = OPOST | ONLCR;
381
382 /* local modes */
Denys Vlasenkof2657a92010-10-24 02:04:10 +0200383 tty.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000384
Denis Vlasenko202ac502008-11-05 13:20:58 +0000385 tcsetattr_stdin_TCSANOW(&tty);
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000386}
387
Denis Vlasenko671ca332008-02-19 14:13:20 +0000388/* Open the new terminal device.
389 * NB: careful, we can be called after vfork! */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000390static int open_stdio_to_tty(const char* tty_name)
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000391{
392 /* empty tty_name means "use init's tty", else... */
393 if (tty_name[0]) {
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000394 int fd;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000395
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000396 close(STDIN_FILENO);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000397 /* fd can be only < 0 or 0: */
398 fd = device_open(tty_name, O_RDWR);
399 if (fd) {
Denys Vlasenko6f97b302017-09-29 18:17:25 +0200400 message(L_LOG | L_CONSOLE, "can't open %s: "STRERROR_FMT,
401 tty_name
402 STRERROR_ERRNO
403 );
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000404 return 0; /* failure */
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000405 }
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000406 dup2(STDIN_FILENO, STDOUT_FILENO);
407 dup2(STDIN_FILENO, STDERR_FILENO);
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000408 }
Denis Vlasenkod238a472007-03-05 19:22:04 +0000409 set_sane_term();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000410 return 1; /* success */
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000411}
412
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100413static void reset_sighandlers_and_unblock_sigs(void)
414{
415 bb_signals(0
416 + (1 << SIGUSR1)
417 + (1 << SIGUSR2)
418 + (1 << SIGTERM)
419 + (1 << SIGQUIT)
420 + (1 << SIGINT)
421 + (1 << SIGHUP)
422 + (1 << SIGTSTP)
Denys Vlasenko18f89122009-12-14 03:08:30 +0100423 + (1 << SIGSTOP)
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100424 , SIG_DFL);
425 sigprocmask_allsigs(SIG_UNBLOCK);
426}
427
Denis Vlasenko671ca332008-02-19 14:13:20 +0000428/* Wrapper around exec:
Denys Vlasenkod2e07bc2013-08-16 11:48:48 +0200429 * Takes string.
Denis Vlasenko671ca332008-02-19 14:13:20 +0000430 * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
431 * Otherwise splits words on whitespace, deals with leading dash,
432 * and uses plain exec().
433 * NB: careful, we can be called after vfork!
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000434 */
435static void init_exec(const char *command)
436{
Denys Vlasenkod2e07bc2013-08-16 11:48:48 +0200437 /* +8 allows to write VLA sizes below more efficiently: */
438 unsigned command_size = strlen(command) + 8;
439 /* strlen(command) + strlen("exec ")+1: */
440 char buf[command_size];
441 /* strlen(command) / 2 + 4: */
442 char *cmd[command_size / 2];
443 int dash;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000444
Denys Vlasenkod2e07bc2013-08-16 11:48:48 +0200445 dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
Denys Vlasenko6088e132010-12-25 23:58:42 +0100446 command += dash;
447
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000448 /* See if any special /bin/sh requiring characters are present */
449 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
Denys Vlasenko6088e132010-12-25 23:58:42 +0100450 sprintf(buf, "exec %s", command); /* excluding "-" */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000451 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000452 cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
453 cmd[1] = (char*)"-c";
454 cmd[2] = buf;
455 cmd[3] = NULL;
Denys Vlasenko6088e132010-12-25 23:58:42 +0100456 command = LIBBB_DEFAULT_LOGIN_SHELL + 1;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000457 } else {
458 /* Convert command (char*) into cmd (char**, one word per string) */
459 char *word, *next;
460 int i = 0;
Denys Vlasenko6088e132010-12-25 23:58:42 +0100461 next = strcpy(buf, command - dash); /* command including "-" */
Denys Vlasenko32176cc2011-03-21 05:07:43 +0100462 command = next + dash;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000463 while ((word = strsep(&next, " \t")) != NULL) {
464 if (*word != '\0') { /* not two spaces/tabs together? */
465 cmd[i] = word;
466 i++;
467 }
468 }
469 cmd[i] = NULL;
470 }
471 /* If we saw leading "-", it is interactive shell.
472 * Try harder to give it a controlling tty.
Denys Vlasenko6088e132010-12-25 23:58:42 +0100473 */
474 if (ENABLE_FEATURE_INIT_SCTTY && dash) {
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000475 /* _Attempt_ to make stdin a controlling tty. */
Denys Vlasenko6088e132010-12-25 23:58:42 +0100476 ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000477 }
Denys Vlasenko6088e132010-12-25 23:58:42 +0100478 /* Here command never contains the dash, cmd[0] might */
479 BB_EXECVP(command, cmd);
Denys Vlasenko6f97b302017-09-29 18:17:25 +0200480 message(L_LOG | L_CONSOLE, "can't run '%s': "STRERROR_FMT, command STRERROR_ERRNO);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000481 /* returns if execvp fails */
482}
483
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000484/* Used only by run_actions */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000485static pid_t run(const struct init_action *a)
Eric Andersen0298be82002-03-05 15:12:19 +0000486{
Mike Frysinger10427ab2005-07-06 05:00:48 +0000487 pid_t pid;
Erik Andersenac6e71f2000-01-08 22:04:33 +0000488
Denis Vlasenko47741792009-03-10 16:01:57 +0000489 /* Careful: don't be affected by a signal in vforked child */
490 sigprocmask_allsigs(SIG_BLOCK);
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000491 if (BB_MMU && (a->action_type & ASKFIRST))
492 pid = fork();
493 else
494 pid = vfork();
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000495 if (pid < 0)
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000496 message(L_LOG | L_CONSOLE, "can't fork");
Denis Vlasenko47741792009-03-10 16:01:57 +0000497 if (pid) {
498 sigprocmask_allsigs(SIG_UNBLOCK);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000499 return pid; /* Parent or error */
Denis Vlasenko47741792009-03-10 16:01:57 +0000500 }
Eric Andersen0298be82002-03-05 15:12:19 +0000501
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000502 /* Child */
503
Denis Vlasenko966bb432007-02-27 19:20:33 +0000504 /* Reset signal handlers that were set by the parent process */
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100505 reset_sighandlers_and_unblock_sigs();
Eric Andersen2f6c04f1999-11-01 23:59:44 +0000506
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000507 /* Create a new session and make ourself the process group leader */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000508 setsid();
Eric Andersen599e3ce2002-07-03 11:08:10 +0000509
Denis Vlasenko966bb432007-02-27 19:20:33 +0000510 /* Open the new terminal device */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000511 if (!open_stdio_to_tty(a->terminal))
512 _exit(EXIT_FAILURE);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000513
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000514 /* NB: on NOMMU we can't wait for input in child, so
515 * "askfirst" will work the same as "respawn". */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000516 if (BB_MMU && (a->action_type & ASKFIRST)) {
Denis Vlasenko6ca409e2007-08-12 20:58:27 +0000517 static const char press_enter[] ALIGN1 =
Denis Vlasenko966bb432007-02-27 19:20:33 +0000518#ifdef CUSTOMIZED_BANNER
519#include CUSTOMIZED_BANNER
Eric Andersen1f50e842004-08-16 09:29:42 +0000520#endif
Denis Vlasenko966bb432007-02-27 19:20:33 +0000521 "\nPlease press Enter to activate this console. ";
522 char c;
523 /*
524 * Save memory by not exec-ing anything large (like a shell)
525 * before the user wants it. This is critical if swap is not
526 * enabled and the system has low memory. Generally this will
527 * be run on the second virtual console, and the first will
528 * be allowed to start a shell or whatever an init script
529 * specifies.
530 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000531 dbg_message(L_LOG, "waiting for enter to start '%s'"
Denis Vlasenko966bb432007-02-27 19:20:33 +0000532 "(pid %d, tty '%s')\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000533 a->command, getpid(), a->terminal);
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000534 full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
535 while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000536 continue;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000537 }
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000538
Denis Vlasenko6c622462009-01-29 02:01:04 +0000539 /*
540 * When a file named /.init_enable_core exists, setrlimit is called
541 * before processes are spawned to set core file size as unlimited.
542 * This is for debugging only. Don't use this is production, unless
543 * you want core dumps lying about....
544 */
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000545 if (ENABLE_FEATURE_INIT_COREDUMPS) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000546 if (access("/.init_enable_core", F_OK) == 0) {
Denis Vlasenko966bb432007-02-27 19:20:33 +0000547 struct rlimit limit;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000548 limit.rlim_cur = RLIM_INFINITY;
549 limit.rlim_max = RLIM_INFINITY;
550 setrlimit(RLIMIT_CORE, &limit);
Erik Andersen983b51b2000-04-04 18:14:25 +0000551 }
Erik Andersen05df2392000-01-13 04:43:48 +0000552 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000553
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000554 /* Log the process name and args */
Denys Vlasenko42776702017-04-07 19:13:09 +0200555 message(L_LOG, "starting pid %u, tty '%s': '%s'",
556 (int)getpid(), a->terminal, a->command);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000557
Denis Vlasenko966bb432007-02-27 19:20:33 +0000558 /* Now run it. The new program will take over this PID,
559 * so nothing further in init.c should be run. */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000560 init_exec(a->command);
Denis Vlasenko966bb432007-02-27 19:20:33 +0000561 /* We're still here? Some error happened. */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000562 _exit(-1);
Eric Andersen0460ff21999-10-25 23:32:44 +0000563}
564
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000565static struct init_action *mark_terminated(pid_t pid)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000566{
567 struct init_action *a;
568
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000569 if (pid > 0) {
Denys Vlasenkoda921262015-01-05 15:37:58 +0100570 update_utmp_DEAD_PROCESS(pid);
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100571 for (a = G.init_action_list; a; a = a->next) {
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000572 if (a->pid == pid) {
573 a->pid = 0;
574 return a;
575 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000576 }
577 }
578 return NULL;
579}
580
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000581static void waitfor(pid_t pid)
582{
583 /* waitfor(run(x)): protect against failed fork inside run() */
584 if (pid <= 0)
585 return;
586
587 /* Wait for any child (prevent zombies from exiting orphaned processes)
588 * but exit the loop only when specified one has exited. */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000589 while (1) {
590 pid_t wpid = wait(NULL);
591 mark_terminated(wpid);
592 /* Unsafe. SIGTSTP handler might have wait'ed it already */
593 /*if (wpid == pid) break;*/
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000594 /* More reliable: */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000595 if (kill(pid, 0))
596 break;
597 }
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000598}
599
Eric Andersen0298be82002-03-05 15:12:19 +0000600/* Run all commands of a particular type */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000601static void run_actions(int action_type)
Eric Andersen219d6f51999-11-02 19:43:01 +0000602{
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000603 struct init_action *a;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000604
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100605 for (a = G.init_action_list; a; a = a->next) {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000606 if (!(a->action_type & action_type))
607 continue;
Eric Andersen5222d312002-07-03 05:15:23 +0000608
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000609 if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
610 pid_t pid = run(a);
611 if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
612 waitfor(pid);
613 }
614 if (a->action_type & (RESPAWN | ASKFIRST)) {
615 /* Only run stuff with pid == 0. If pid != 0,
616 * it is already running
617 */
618 if (a->pid == 0)
619 a->pid = run(a);
Eric Andersen730f8262001-12-17 23:13:08 +0000620 }
621 }
622}
623
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000624static void new_init_action(uint8_t action_type, const char *command, const char *cons)
Erik Andersen7dc16072000-01-04 01:10:25 +0000625{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000626 struct init_action *a, **nextp;
Erik Andersen9e737252000-01-06 01:16:13 +0000627
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000628 /* Scenario:
629 * old inittab:
630 * ::shutdown:umount -a -r
631 * ::shutdown:swapoff -a
632 * new inittab:
633 * ::shutdown:swapoff -a
634 * ::shutdown:umount -a -r
635 * On reload, we must ensure entries end up in correct order.
636 * To achieve that, if we find a matching entry, we move it
637 * to the end.
638 */
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100639 nextp = &G.init_action_list;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000640 while ((a = *nextp) != NULL) {
Denys Vlasenkoef7aa462011-12-05 03:54:28 +0100641 /* Don't enter action if it's already in the list.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000642 * This prevents losing running RESPAWNs.
643 */
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100644 if (strcmp(a->command, command) == 0
645 && strcmp(a->terminal, cons) == 0
Denis Vlasenkob74a2db2008-07-21 21:34:51 +0000646 ) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000647 /* Remove from list */
648 *nextp = a->next;
649 /* Find the end of the list */
650 while (*nextp != NULL)
651 nextp = &(*nextp)->next;
652 a->next = NULL;
Denys Vlasenkoef7aa462011-12-05 03:54:28 +0100653 goto append;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000654 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000655 nextp = &a->next;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000656 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000657
Denys Vlasenkod2e07bc2013-08-16 11:48:48 +0200658 a = xzalloc(sizeof(*a) + strlen(command));
Denys Vlasenkoef7aa462011-12-05 03:54:28 +0100659
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000660 /* Append to the end of the list */
Denys Vlasenkoef7aa462011-12-05 03:54:28 +0100661 append:
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000662 *nextp = a;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000663 a->action_type = action_type;
Denys Vlasenkod2e07bc2013-08-16 11:48:48 +0200664 strcpy(a->command, command);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000665 safe_strncpy(a->terminal, cons, sizeof(a->terminal));
Paulius Zaleckas9f07af62013-08-16 12:01:58 +0200666 dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%x tty='%s'\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000667 a->command, a->action_type, a->terminal);
Erik Andersen7dc16072000-01-04 01:10:25 +0000668}
669
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000670/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersen9e737252000-01-06 01:16:13 +0000671 * then parse_inittab() simply adds in some default
Denys Vlasenkof9584252013-05-21 16:36:51 +0200672 * actions (i.e., runs INIT_SCRIPT and then starts a pair
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000673 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
674 * _is_ defined, but /etc/inittab is missing, this
Erik Andersen812d4662000-01-07 18:30:40 +0000675 * results in the same set of default behaviors.
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000676 */
Eric Andersen3e6ff902001-03-09 21:24:12 +0000677static void parse_inittab(void)
Erik Andersen7dc16072000-01-04 01:10:25 +0000678{
Denis Vlasenko6c622462009-01-29 02:01:04 +0000679#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000680 char *token[4];
Denis Vlasenko6c622462009-01-29 02:01:04 +0000681 parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000682
Denis Vlasenko6c622462009-01-29 02:01:04 +0000683 if (parser == NULL)
684#endif
685 {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000686 /* No inittab file - set up some default behavior */
Denys Vlasenkof9584252013-05-21 16:36:51 +0200687 /* Sysinit */
688 new_init_action(SYSINIT, INIT_SCRIPT, "");
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000689 /* Askfirst shell on tty1-4 */
690 new_init_action(ASKFIRST, bb_default_login_shell, "");
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000691//TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000692 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
693 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
694 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
Denys Vlasenkof9584252013-05-21 16:36:51 +0200695 /* Reboot on Ctrl-Alt-Del */
696 new_init_action(CTRLALTDEL, "reboot", "");
697 /* Umount all filesystems on halt/reboot */
698 new_init_action(SHUTDOWN, "umount -a -r", "");
699 /* Swapoff on halt/reboot */
700 new_init_action(SHUTDOWN, "swapoff -a", "");
701 /* Restart init when a QUIT is received */
702 new_init_action(RESTART, "init", "");
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000703 return;
704 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000705
706#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000707 /* optional_tty:ignored_runlevel:action:command
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000708 * Delims are not to be collapsed and need exactly 4 tokens
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000709 */
Denis Vlasenko084266e2008-07-26 23:08:31 +0000710 while (config_read(parser, token, 4, 0, "#:",
711 PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000712 /* order must correspond to SYSINIT..RESTART constants */
713 static const char actions[] ALIGN1 =
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000714 "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
Denis Vlasenko6c622462009-01-29 02:01:04 +0000715 "ctrlaltdel\0""shutdown\0""restart\0";
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000716 int action;
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000717 char *tty = token[0];
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000718
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000719 if (!token[3]) /* less than 4 tokens */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000720 goto bad_entry;
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000721 action = index_in_strings(actions, token[2]);
722 if (action < 0 || !token[3][0]) /* token[3]: command */
723 goto bad_entry;
724 /* turn .*TTY -> /dev/TTY */
725 if (tty[0]) {
Denys Vlasenkof8d8aa12010-04-06 18:50:05 +0200726 tty = concat_path_file("/dev/", skip_dev_pfx(tty));
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000727 }
728 new_init_action(1 << action, token[3], tty);
729 if (tty[0])
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000730 free(tty);
731 continue;
732 bad_entry:
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000733 message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
734 parser->lineno);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000735 }
736 config_close(parser);
Denis Vlasenko6c622462009-01-29 02:01:04 +0000737#endif
Erik Andersen7dc16072000-01-04 01:10:25 +0000738}
739
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000740static void pause_and_low_level_reboot(unsigned magic) NORETURN;
741static void pause_and_low_level_reboot(unsigned magic)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000742{
743 pid_t pid;
744
745 /* Allow time for last message to reach serial console, etc */
746 sleep(1);
747
748 /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
749 * in linux/kernel/sys.c, which can cause the machine to panic when
750 * the init process exits... */
751 pid = vfork();
752 if (pid == 0) { /* child */
753 reboot(magic);
754 _exit(EXIT_SUCCESS);
755 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000756 while (1)
757 sleep(1);
758}
759
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000760static void run_shutdown_and_kill_processes(void)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000761{
762 /* Run everything to be run at "shutdown". This is done _prior_
763 * to killing everything, in case people wish to use scripts to
764 * shut things down gracefully... */
765 run_actions(SHUTDOWN);
766
767 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
768
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000769 /* Send signals to every process _except_ pid 1 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000770 kill(-1, SIGTERM);
Denys Vlasenko42776702017-04-07 19:13:09 +0200771 message(L_CONSOLE, "Sent SIG%s to all processes", "TERM");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000772 sync();
773 sleep(1);
774
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000775 kill(-1, SIGKILL);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000776 message(L_CONSOLE, "Sent SIG%s to all processes", "KILL");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000777 sync();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000778 /*sleep(1); - callers take care about making a pause */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000779}
780
781/* Signal handling by init:
782 *
783 * For process with PID==1, on entry kernel sets all signals to SIG_DFL
784 * and unmasks all signals. However, for process with PID==1,
785 * default action (SIG_DFL) on any signal is to ignore it,
786 * even for special signals SIGKILL and SIGCONT.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000787 * Also, any signal can be caught or blocked.
Denis Vlasenkofc2a4fc2009-01-31 01:07:05 +0000788 * (but SIGSTOP is still handled specially, at least in 2.6.20)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000789 *
790 * We install two kinds of handlers, "immediate" and "delayed".
791 *
792 * Immediate handlers execute at any time, even while, say, sysinit
793 * is running.
794 *
795 * Delayed handlers just set a flag variable. The variable is checked
796 * in the main loop and acted upon.
797 *
798 * halt/poweroff/reboot and restart have immediate handlers.
799 * They only traverse linked list of struct action's, never modify it,
800 * this should be safe to do even in signal handler. Also they
801 * never return.
802 *
803 * SIGSTOP and SIGTSTP have immediate handlers. They just wait
804 * for SIGCONT to happen.
805 *
806 * SIGHUP has a delayed handler, because modifying linked list
807 * of struct action's from a signal handler while it is manipulated
808 * by the program may be disastrous.
809 *
810 * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
811 * it to happen even somewhere inside "sysinit" would be a bit awkward.
812 *
813 * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
Denis Vlasenko93b38202009-02-14 20:58:13 +0000814 * and only one will be remembered and acted upon.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000815 */
816
Bogdan Purcareata760fc6d2013-11-26 13:54:48 +0100817/* The SIGPWR/SIGUSR[12]/SIGTERM handler */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000818static void halt_reboot_pwoff(int sig) NORETURN;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000819static void halt_reboot_pwoff(int sig)
820{
821 const char *m;
822 unsigned rb;
823
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100824 /* We may call run() and it unmasks signals,
825 * including the one masked inside this signal handler.
826 * Testcase which would start multiple reboot scripts:
827 * while true; do reboot; done
828 * Preventing it:
829 */
830 reset_sighandlers_and_unblock_sigs();
831
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000832 run_shutdown_and_kill_processes();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000833
834 m = "halt";
835 rb = RB_HALT_SYSTEM;
836 if (sig == SIGTERM) {
837 m = "reboot";
838 rb = RB_AUTOBOOT;
839 } else if (sig == SIGUSR2) {
840 m = "poweroff";
841 rb = RB_POWER_OFF;
842 }
843 message(L_CONSOLE, "Requesting system %s", m);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000844 pause_and_low_level_reboot(rb);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000845 /* not reached */
846}
847
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100848/* Handler for QUIT - exec "restart" action,
849 * else (no such action defined) do nothing */
Denys Vlasenko2bba9ad2014-11-21 20:10:57 +0100850static void exec_restart_action(void)
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100851{
852 struct init_action *a;
853
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100854 for (a = G.init_action_list; a; a = a->next) {
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100855 if (!(a->action_type & RESTART))
856 continue;
857
858 /* Starting from here, we won't return.
859 * Thus don't need to worry about preserving errno
860 * and such.
861 */
862
863 reset_sighandlers_and_unblock_sigs();
864
865 run_shutdown_and_kill_processes();
866
Jeremie Koenig714674e2010-05-27 15:38:44 +0200867#ifdef RB_ENABLE_CAD
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100868 /* Allow Ctrl-Alt-Del to reboot the system.
869 * This is how kernel sets it up for init, we follow suit.
870 */
871 reboot(RB_ENABLE_CAD); /* misnomer */
Jeremie Koenig714674e2010-05-27 15:38:44 +0200872#endif
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100873
874 if (open_stdio_to_tty(a->terminal)) {
875 dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
876 /* Theoretically should be safe.
877 * But in practice, kernel bugs may leave
878 * unkillable processes, and wait() may block forever.
879 * Oh well. Hoping "new" init won't be too surprised
880 * by having children it didn't create.
881 */
882 //while (wait(NULL) > 0)
883 // continue;
884 init_exec(a->command);
885 }
886 /* Open or exec failed */
887 pause_and_low_level_reboot(RB_HALT_SYSTEM);
888 /* not reached */
889 }
890}
891
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000892/* The SIGSTOP/SIGTSTP handler
893 * NB: inside it, all signals except SIGCONT are masked
894 * via appropriate setup in sigaction().
895 */
896static void stop_handler(int sig UNUSED_PARAM)
897{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000898 smallint saved_bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000899 int saved_errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000900
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000901 saved_bb_got_signal = bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000902 saved_errno = errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000903 signal(SIGCONT, record_signo);
904
905 while (1) {
906 pid_t wpid;
907
908 if (bb_got_signal == SIGCONT)
909 break;
910 /* NB: this can accidentally wait() for a process
911 * which we waitfor() elsewhere! waitfor() must have
912 * code which is resilient against this.
913 */
914 wpid = wait_any_nohang(NULL);
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000915 mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000916 sleep(1);
917 }
918
919 signal(SIGCONT, SIG_DFL);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000920 errno = saved_errno;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000921 bb_got_signal = saved_bb_got_signal;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000922}
923
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000924#if ENABLE_FEATURE_USE_INITTAB
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000925static void reload_inittab(void)
Eric Andersen6fd0e312003-07-22 09:48:56 +0000926{
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000927 struct init_action *a, **nextp;
Eric Andersen82baf632004-10-08 08:21:54 +0000928
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000929 message(L_LOG, "reloading /etc/inittab");
Eric Andersen82baf632004-10-08 08:21:54 +0000930
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000931 /* Disable old entries */
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100932 for (a = G.init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100933 a->action_type = 0;
Eric Andersen82baf632004-10-08 08:21:54 +0000934
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000935 /* Append new entries, or modify existing entries
Denys Vlasenko6e542492009-11-15 03:07:19 +0100936 * (incl. setting a->action_type) if cmd and device name
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000937 * match new ones. End result: only entries with
Denys Vlasenko6e542492009-11-15 03:07:19 +0100938 * a->action_type == 0 are stale.
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000939 */
Eric Andersen82baf632004-10-08 08:21:54 +0000940 parse_inittab();
941
Denis Vlasenko93b38202009-02-14 20:58:13 +0000942#if ENABLE_FEATURE_KILL_REMOVED
943 /* Kill stale entries */
944 /* Be nice and send SIGTERM first */
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100945 for (a = G.init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100946 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000947 kill(a->pid, SIGTERM);
948 if (CONFIG_FEATURE_KILL_DELAY) {
949 /* NB: parent will wait in NOMMU case */
950 if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
951 sleep(CONFIG_FEATURE_KILL_DELAY);
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100952 for (a = G.init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100953 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000954 kill(a->pid, SIGKILL);
955 _exit(EXIT_SUCCESS);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000956 }
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000957 }
Denis Vlasenko93b38202009-02-14 20:58:13 +0000958#endif
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000959
Denys Vlasenko6e542492009-11-15 03:07:19 +0100960 /* Remove stale entries and SYSINIT entries.
961 * We never rerun SYSINIT entries anyway,
Paulius Zaleckas9f07af62013-08-16 12:01:58 +0200962 * removing them too saves a few bytes
963 */
Denys Vlasenkof2539c72018-01-10 13:32:20 +0100964 nextp = &G.init_action_list;
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000965 while ((a = *nextp) != NULL) {
Paulius Zaleckas9f07af62013-08-16 12:01:58 +0200966 /*
967 * Why pid == 0 check?
968 * Process can be removed from inittab and added *later*.
969 * If we delete its entry but process still runs,
970 * duplicate is spawned when the entry is re-added.
971 */
972 if ((a->action_type & ~SYSINIT) == 0 && a->pid == 0) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000973 *nextp = a->next;
974 free(a);
975 } else {
976 nextp = &a->next;
977 }
Eric Andersen82baf632004-10-08 08:21:54 +0000978 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000979
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000980 /* Not needed: */
981 /* run_actions(RESPAWN | ASKFIRST); */
982 /* - we return to main loop, which does this automagically */
Eric Andersen6fd0e312003-07-22 09:48:56 +0000983}
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000984#endif
Eric Andersen82baf632004-10-08 08:21:54 +0000985
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000986static int check_delayed_sigs(void)
987{
988 int sigs_seen = 0;
989
990 while (1) {
991 smallint sig = bb_got_signal;
992
993 if (!sig)
994 return sigs_seen;
995 bb_got_signal = 0;
996 sigs_seen = 1;
997#if ENABLE_FEATURE_USE_INITTAB
998 if (sig == SIGHUP)
999 reload_inittab();
1000#endif
1001 if (sig == SIGINT)
1002 run_actions(CTRLALTDEL);
Denys Vlasenko2bba9ad2014-11-21 20:10:57 +01001003 if (sig == SIGQUIT) {
1004 exec_restart_action();
1005 /* returns only if no restart action defined */
1006 }
1007 if ((1 << sig) & (0
1008#ifdef SIGPWR
1009 + (1 << SIGPWR)
1010#endif
1011 + (1 << SIGUSR1)
1012 + (1 << SIGUSR2)
1013 + (1 << SIGTERM)
1014 )) {
1015 halt_reboot_pwoff(sig);
1016 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001017 }
1018}
1019
Denys Vlasenkoda2b2da2012-01-30 12:15:22 +01001020#if DEBUG_SEGV_HANDLER
1021static
1022void handle_sigsegv(int sig, siginfo_t *info, void *ucontext)
1023{
1024 long ip;
1025 ucontext_t *uc;
1026
1027 uc = ucontext;
1028 ip = uc->uc_mcontext.gregs[REG_EIP];
1029 fdprintf(2, "signal:%d address:0x%lx ip:0x%lx\n",
1030 sig,
1031 /* this is void*, but using %p would print "(null)"
1032 * even for ptrs which are not exactly 0, but, say, 0x123:
1033 */
1034 (long)info->si_addr,
1035 ip);
1036 {
1037 /* glibc extension */
1038 void *array[50];
1039 int size;
1040 size = backtrace(array, 50);
1041 backtrace_symbols_fd(array, size, 2);
1042 }
1043 for (;;) sleep(9999);
1044}
1045#endif
1046
Denys Vlasenko550bf5b2015-10-09 16:42:57 +02001047static void sleep_much(void)
1048{
1049 sleep(30 * 24*60*60);
1050}
1051
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +00001052int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +00001053int init_main(int argc UNUSED_PARAM, char **argv)
Eric Andersen0460ff21999-10-25 23:32:44 +00001054{
Denys Vlasenkof2539c72018-01-10 13:32:20 +01001055 INIT_G();
1056
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +01001057 if (argv[1] && strcmp(argv[1], "-q") == 0) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +00001058 return kill(1, SIGHUP);
Eric Andersen730f8262001-12-17 23:13:08 +00001059 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +00001060
Denys Vlasenkoda2b2da2012-01-30 12:15:22 +01001061#if DEBUG_SEGV_HANDLER
1062 {
1063 struct sigaction sa;
1064 memset(&sa, 0, sizeof(sa));
1065 sa.sa_sigaction = handle_sigsegv;
1066 sa.sa_flags = SA_SIGINFO;
1067 sigaction(SIGSEGV, &sa, NULL);
1068 sigaction(SIGILL, &sa, NULL);
1069 sigaction(SIGFPE, &sa, NULL);
1070 sigaction(SIGBUS, &sa, NULL);
1071 }
1072#endif
1073
Denis Vlasenko5cb54b52008-10-21 17:14:26 +00001074 if (!DEBUG_INIT) {
Denys Vlasenkof5e8b422017-11-02 15:25:28 +01001075 /* Some users send poweroff signals to init VERY early.
1076 * To handle this, mask signals early,
1077 * and unmask them only after signal handlers are installed.
1078 */
1079 sigprocmask_allsigs(SIG_BLOCK);
1080
Mike Frysingerbb50fdf2007-12-25 04:30:14 +00001081 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
1082 if (getpid() != 1
Denys Vlasenko52977a72016-03-31 00:42:57 +02001083 && (!ENABLE_LINUXRC || applet_name[0] != 'l') /* not linuxrc? */
Mike Frysingerbb50fdf2007-12-25 04:30:14 +00001084 ) {
Denys Vlasenkodb5fe622010-11-02 20:13:03 +01001085 bb_error_msg_and_die("must be run as PID 1");
Mike Frysingerbb50fdf2007-12-25 04:30:14 +00001086 }
Jeremie Koenig714674e2010-05-27 15:38:44 +02001087#ifdef RB_DISABLE_CAD
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001088 /* Turn off rebooting via CTL-ALT-DEL - we get a
Mike Frysingerbb50fdf2007-12-25 04:30:14 +00001089 * SIGINT on CAD so we can shut things down gracefully... */
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001090 reboot(RB_DISABLE_CAD); /* misnomer */
Jeremie Koenig714674e2010-05-27 15:38:44 +02001091#endif
Erik Andersene49d5ec2000-02-08 19:58:47 +00001092 }
Denis Vlasenkod8540f72007-06-14 07:53:06 +00001093
Denys Vlasenko3b060522010-10-25 00:40:32 +02001094 /* If, say, xmalloc would ever die, we don't want to oops kernel
1095 * by exiting.
Denys Vlasenko550bf5b2015-10-09 16:42:57 +02001096 * NB: we set die_func *after* PID 1 check and bb_show_usage.
Denys Vlasenko3b060522010-10-25 00:40:32 +02001097 * Otherwise, for example, "init u" ("please rexec yourself"
1098 * command for sysvinit) will show help text (which isn't too bad),
1099 * *and sleep forever* (which is bad!)
1100 */
Denys Vlasenko550bf5b2015-10-09 16:42:57 +02001101 die_func = sleep_much;
Denys Vlasenko3b060522010-10-25 00:40:32 +02001102
Eric Andersen599e3ce2002-07-03 11:08:10 +00001103 /* Figure out where the default console should be */
1104 console_init();
Denis Vlasenkod238a472007-03-05 19:22:04 +00001105 set_sane_term();
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +00001106 xchdir("/");
Erik Andersene49d5ec2000-02-08 19:58:47 +00001107 setsid();
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +00001108
1109 /* Make sure environs is set to something sane */
1110 putenv((char *) "HOME=/");
1111 putenv((char *) bb_PATH_root_path);
1112 putenv((char *) "SHELL=/bin/sh");
1113 putenv((char *) "USER=root"); /* needed? why? */
Rob Landleycba1b962006-07-09 17:28:17 +00001114
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +00001115 if (argv[1])
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +00001116 xsetenv("RUNLEVEL", argv[1]);
Rob Landleycba1b962006-07-09 17:28:17 +00001117
Denys Vlasenkof35ad3b2017-01-10 15:24:13 +01001118#if !ENABLE_FEATURE_INIT_QUIET
Erik Andersene49d5ec2000-02-08 19:58:47 +00001119 /* Hello world */
Denys Vlasenko6be918d2009-12-14 01:32:11 +01001120 message(L_CONSOLE | L_LOG, "init started: %s", bb_banner);
1121#endif
Eric Andersencc8ed391999-10-05 16:24:54 +00001122
Erik Andersene49d5ec2000-02-08 19:58:47 +00001123 /* Check if we are supposed to be in single user mode */
Denis Vlasenko1d426652008-03-17 09:09:09 +00001124 if (argv[1]
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +01001125 && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1'))
Denis Vlasenkobf66fbc2006-12-21 13:23:14 +00001126 ) {
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +00001127 /* ??? shouldn't we set RUNLEVEL="b" here? */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +00001128 /* Start a shell on console */
Glenn L McGrathdc4e75e2003-09-02 02:36:18 +00001129 new_init_action(RESPAWN, bb_default_login_shell, "");
Erik Andersene49d5ec2000-02-08 19:58:47 +00001130 } else {
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001131 /* Not in single user mode - see what inittab says */
Eric Andersen8a8fbb81999-10-26 00:18:56 +00001132
Eric Andersenbdfd0d72001-10-24 05:00:29 +00001133 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersene49d5ec2000-02-08 19:58:47 +00001134 * then parse_inittab() simply adds in some default
Bogdan Purcareata760fc6d2013-11-26 13:54:48 +01001135 * actions (i.e., INIT_SCRIPT and a pair
1136 * of "askfirst" shells) */
Erik Andersene49d5ec2000-02-08 19:58:47 +00001137 parse_inittab();
Eric Andersend00c2621999-12-07 08:37:31 +00001138 }
Erik Andersen983b51b2000-04-04 18:14:25 +00001139
Denis Vlasenko9b1381f2007-01-03 02:56:00 +00001140#if ENABLE_SELINUX
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001141 if (getenv("SELINUX_INIT") == NULL) {
1142 int enforce = 0;
1143
Denis Vlasenkod8540f72007-06-14 07:53:06 +00001144 putenv((char*)"SELINUX_INIT=YES");
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001145 if (selinux_init_load_policy(&enforce) == 0) {
Denis Vlasenko4921b542007-02-03 02:17:41 +00001146 BB_EXECVP(argv[0], argv);
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001147 } else if (enforce > 0) {
1148 /* SELinux in enforcing mode but load_policy failed */
Denys Vlasenko6331cf02009-11-13 09:08:27 +01001149 message(L_CONSOLE, "can't load SELinux Policy. "
Denis Vlasenkob7167542007-02-27 19:20:00 +00001150 "Machine is in enforcing mode. Halting now.");
Denys Vlasenko3b060522010-10-25 00:40:32 +02001151 return EXIT_FAILURE;
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001152 }
1153 }
Denis Vlasenko6c622462009-01-29 02:01:04 +00001154#endif
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001155
Nicolas Carrier29eae722016-02-04 12:18:01 +01001156 if (ENABLE_FEATURE_INIT_MODIFY_CMDLINE) {
1157 /* Make the command line just say "init" - that's all, nothing else */
1158 strncpy(argv[0], "init", strlen(argv[0]));
1159 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
1160 while (*++argv)
1161 nuke_str(*argv);
1162 }
Eric Andersen219d6f51999-11-02 19:43:01 +00001163
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001164 /* Set up signal handlers */
1165 if (!DEBUG_INIT) {
1166 struct sigaction sa;
Erik Andersene49d5ec2000-02-08 19:58:47 +00001167
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001168 /* Stop handler must allow only SIGCONT inside itself */
1169 memset(&sa, 0, sizeof(sa));
1170 sigfillset(&sa.sa_mask);
1171 sigdelset(&sa.sa_mask, SIGCONT);
1172 sa.sa_handler = stop_handler;
1173 /* NB: sa_flags doesn't have SA_RESTART.
1174 * It must be able to interrupt wait().
1175 */
1176 sigaction_set(SIGTSTP, &sa); /* pause */
1177 /* Does not work as intended, at least in 2.6.20.
1178 * SIGSTOP is simply ignored by init:
1179 */
1180 sigaction_set(SIGSTOP, &sa); /* pause */
1181
Denys Vlasenko2bba9ad2014-11-21 20:10:57 +01001182 /* These signals must interrupt wait(),
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001183 * setting handler without SA_RESTART flag.
1184 */
Denys Vlasenko2bba9ad2014-11-21 20:10:57 +01001185 bb_signals_recursive_norestart(0
1186 + (1 << SIGINT) /* Ctrl-Alt-Del */
1187 + (1 << SIGQUIT) /* re-exec another init */
1188#ifdef SIGPWR
1189 + (1 << SIGPWR) /* halt */
1190#endif
1191 + (1 << SIGUSR1) /* halt */
1192 + (1 << SIGTERM) /* reboot */
1193 + (1 << SIGUSR2) /* poweroff */
1194#if ENABLE_FEATURE_USE_INITTAB
1195 + (1 << SIGHUP) /* reread /etc/inittab */
1196#endif
1197 , record_signo);
Denys Vlasenkof5e8b422017-11-02 15:25:28 +01001198
1199 sigprocmask_allsigs(SIG_UNBLOCK);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001200 }
1201
1202 /* Now run everything that needs to be run */
Erik Andersene49d5ec2000-02-08 19:58:47 +00001203 /* First run the sysinit command */
Eric Andersen1644db92001-09-05 20:18:15 +00001204 run_actions(SYSINIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001205 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +00001206 /* Next run anything that wants to block */
Eric Andersen1644db92001-09-05 20:18:15 +00001207 run_actions(WAIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001208 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +00001209 /* Next run anything to be run only once */
Eric Andersen0298be82002-03-05 15:12:19 +00001210 run_actions(ONCE);
1211
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001212 /* Now run the looping stuff for the rest of forever.
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001213 */
Erik Andersene49d5ec2000-02-08 19:58:47 +00001214 while (1) {
Denis Vlasenko47741792009-03-10 16:01:57 +00001215 int maybe_WNOHANG;
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001216
Denis Vlasenko47741792009-03-10 16:01:57 +00001217 maybe_WNOHANG = check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001218
1219 /* (Re)run the respawn/askfirst stuff */
Denis Vlasenkoad4da982008-04-05 04:24:23 +00001220 run_actions(RESPAWN | ASKFIRST);
Denis Vlasenko47741792009-03-10 16:01:57 +00001221 maybe_WNOHANG |= check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001222
1223 /* Don't consume all CPU time - sleep a bit */
Eric Andersen0298be82002-03-05 15:12:19 +00001224 sleep(1);
Denis Vlasenko47741792009-03-10 16:01:57 +00001225 maybe_WNOHANG |= check_delayed_sigs();
Eric Andersen0298be82002-03-05 15:12:19 +00001226
Denis Vlasenko47741792009-03-10 16:01:57 +00001227 /* Wait for any child process(es) to exit.
Denys Vlasenko3ed181b2009-07-19 14:29:18 +02001228 *
1229 * If check_delayed_sigs above reported that a signal
1230 * was caught, wait will be nonblocking. This ensures
1231 * that if SIGHUP has reloaded inittab, respawn and askfirst
1232 * actions will not be delayed until next child death.
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001233 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001234 if (maybe_WNOHANG)
1235 maybe_WNOHANG = WNOHANG;
1236 while (1) {
1237 pid_t wpid;
1238 struct init_action *a;
1239
Denys Vlasenko3ed181b2009-07-19 14:29:18 +02001240 /* If signals happen _in_ the wait, they interrupt it,
1241 * bb_signals_recursive_norestart set them up that way
1242 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001243 wpid = waitpid(-1, NULL, maybe_WNOHANG);
1244 if (wpid <= 0)
1245 break;
1246
1247 a = mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001248 if (a) {
1249 message(L_LOG, "process '%s' (pid %d) exited. "
1250 "Scheduling for restart.",
1251 a->command, wpid);
Erik Andersene49d5ec2000-02-08 19:58:47 +00001252 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001253 /* See if anyone else is waiting to be reaped */
Denis Vlasenko47741792009-03-10 16:01:57 +00001254 maybe_WNOHANG = WNOHANG;
Erik Andersene49d5ec2000-02-08 19:58:47 +00001255 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001256 } /* while (1) */
Eric Andersencc8ed391999-10-05 16:24:54 +00001257}
Denys Vlasenkodb5fe622010-11-02 20:13:03 +01001258
1259//usage:#define linuxrc_trivial_usage NOUSAGE_STR
1260//usage:#define linuxrc_full_usage ""
1261
1262//usage:#define init_trivial_usage
1263//usage: ""
1264//usage:#define init_full_usage "\n\n"
Denys Vlasenko730e4d82013-10-12 04:52:22 +02001265//usage: "Init is the first process started during boot. It never exits."
1266//usage: IF_FEATURE_USE_INITTAB(
1267//usage: "\n""It (re)spawns children according to /etc/inittab."
1268//usage: )
1269//usage: IF_NOT_FEATURE_USE_INITTAB(
1270//usage: "\n""This version of init doesn't use /etc/inittab,"
1271//usage: "\n""has fixed set of processed to run."
1272//usage: )
Denys Vlasenkodb5fe622010-11-02 20:13:03 +01001273//usage:
1274//usage:#define init_notes_usage
1275//usage: "This version of init is designed to be run only by the kernel.\n"
1276//usage: "\n"
1277//usage: "BusyBox init doesn't support multiple runlevels. The runlevels field of\n"
1278//usage: "the /etc/inittab file is completely ignored by BusyBox init. If you want\n"
1279//usage: "runlevels, use sysvinit.\n"
1280//usage: "\n"
1281//usage: "BusyBox init works just fine without an inittab. If no inittab is found,\n"
1282//usage: "it has the following default behavior:\n"
1283//usage: "\n"
1284//usage: " ::sysinit:/etc/init.d/rcS\n"
1285//usage: " ::askfirst:/bin/sh\n"
1286//usage: " ::ctrlaltdel:/sbin/reboot\n"
1287//usage: " ::shutdown:/sbin/swapoff -a\n"
1288//usage: " ::shutdown:/bin/umount -a -r\n"
1289//usage: " ::restart:/sbin/init\n"
Denys Vlasenkodb5fe622010-11-02 20:13:03 +01001290//usage: " tty2::askfirst:/bin/sh\n"
1291//usage: " tty3::askfirst:/bin/sh\n"
1292//usage: " tty4::askfirst:/bin/sh\n"
1293//usage: "\n"
1294//usage: "If you choose to use an /etc/inittab file, the inittab entry format is as follows:\n"
1295//usage: "\n"
1296//usage: " <id>:<runlevels>:<action>:<process>\n"
1297//usage: "\n"
1298//usage: " <id>:\n"
1299//usage: "\n"
1300//usage: " WARNING: This field has a non-traditional meaning for BusyBox init!\n"
1301//usage: " The id field is used by BusyBox init to specify the controlling tty for\n"
1302//usage: " the specified process to run on. The contents of this field are\n"
1303//usage: " appended to \"/dev/\" and used as-is. There is no need for this field to\n"
1304//usage: " be unique, although if it isn't you may have strange results. If this\n"
Denys Vlasenko2c0508b2013-03-29 14:35:44 +01001305//usage: " field is left blank, then the init's stdin/out will be used.\n"
Denys Vlasenkodb5fe622010-11-02 20:13:03 +01001306//usage: "\n"
1307//usage: " <runlevels>:\n"
1308//usage: "\n"
1309//usage: " The runlevels field is completely ignored.\n"
1310//usage: "\n"
1311//usage: " <action>:\n"
1312//usage: "\n"
1313//usage: " Valid actions include: sysinit, respawn, askfirst, wait,\n"
1314//usage: " once, restart, ctrlaltdel, and shutdown.\n"
1315//usage: "\n"
1316//usage: " The available actions can be classified into two groups: actions\n"
1317//usage: " that are run only once, and actions that are re-run when the specified\n"
1318//usage: " process exits.\n"
1319//usage: "\n"
1320//usage: " Run only-once actions:\n"
1321//usage: "\n"
1322//usage: " 'sysinit' is the first item run on boot. init waits until all\n"
1323//usage: " sysinit actions are completed before continuing. Following the\n"
1324//usage: " completion of all sysinit actions, all 'wait' actions are run.\n"
1325//usage: " 'wait' actions, like 'sysinit' actions, cause init to wait until\n"
1326//usage: " the specified task completes. 'once' actions are asynchronous,\n"
1327//usage: " therefore, init does not wait for them to complete. 'restart' is\n"
1328//usage: " the action taken to restart the init process. By default this should\n"
1329//usage: " simply run /sbin/init, but can be a script which runs pivot_root or it\n"
1330//usage: " can do all sorts of other interesting things. The 'ctrlaltdel' init\n"
1331//usage: " actions are run when the system detects that someone on the system\n"
1332//usage: " console has pressed the CTRL-ALT-DEL key combination. Typically one\n"
1333//usage: " wants to run 'reboot' at this point to cause the system to reboot.\n"
1334//usage: " Finally the 'shutdown' action specifies the actions to taken when\n"
1335//usage: " init is told to reboot. Unmounting filesystems and disabling swap\n"
1336//usage: " is a very good here.\n"
1337//usage: "\n"
1338//usage: " Run repeatedly actions:\n"
1339//usage: "\n"
1340//usage: " 'respawn' actions are run after the 'once' actions. When a process\n"
1341//usage: " started with a 'respawn' action exits, init automatically restarts\n"
1342//usage: " it. Unlike sysvinit, BusyBox init does not stop processes from\n"
1343//usage: " respawning out of control. The 'askfirst' actions acts just like\n"
1344//usage: " respawn, except that before running the specified process it\n"
1345//usage: " displays the line \"Please press Enter to activate this console.\"\n"
1346//usage: " and then waits for the user to press enter before starting the\n"
1347//usage: " specified process.\n"
1348//usage: "\n"
1349//usage: " Unrecognized actions (like initdefault) will cause init to emit an\n"
1350//usage: " error message, and then go along with its business. All actions are\n"
1351//usage: " run in the order they appear in /etc/inittab.\n"
1352//usage: "\n"
1353//usage: " <process>:\n"
1354//usage: "\n"
1355//usage: " Specifies the process to be executed and its command line.\n"
1356//usage: "\n"
1357//usage: "Example /etc/inittab file:\n"
1358//usage: "\n"
1359//usage: " # This is run first except when booting in single-user mode\n"
1360//usage: " #\n"
1361//usage: " ::sysinit:/etc/init.d/rcS\n"
1362//usage: " \n"
1363//usage: " # /bin/sh invocations on selected ttys\n"
1364//usage: " #\n"
1365//usage: " # Start an \"askfirst\" shell on the console (whatever that may be)\n"
1366//usage: " ::askfirst:-/bin/sh\n"
1367//usage: " # Start an \"askfirst\" shell on /dev/tty2-4\n"
1368//usage: " tty2::askfirst:-/bin/sh\n"
1369//usage: " tty3::askfirst:-/bin/sh\n"
1370//usage: " tty4::askfirst:-/bin/sh\n"
1371//usage: " \n"
1372//usage: " # /sbin/getty invocations for selected ttys\n"
1373//usage: " #\n"
1374//usage: " tty4::respawn:/sbin/getty 38400 tty4\n"
1375//usage: " tty5::respawn:/sbin/getty 38400 tty5\n"
1376//usage: " \n"
1377//usage: " \n"
1378//usage: " # Example of how to put a getty on a serial line (for a terminal)\n"
1379//usage: " #\n"
1380//usage: " #::respawn:/sbin/getty -L ttyS0 9600 vt100\n"
1381//usage: " #::respawn:/sbin/getty -L ttyS1 9600 vt100\n"
1382//usage: " #\n"
1383//usage: " # Example how to put a getty on a modem line\n"
1384//usage: " #::respawn:/sbin/getty 57600 ttyS2\n"
1385//usage: " \n"
1386//usage: " # Stuff to do when restarting the init process\n"
1387//usage: " ::restart:/sbin/init\n"
1388//usage: " \n"
1389//usage: " # Stuff to do before rebooting\n"
1390//usage: " ::ctrlaltdel:/sbin/reboot\n"
1391//usage: " ::shutdown:/bin/umount -a -r\n"
1392//usage: " ::shutdown:/sbin/swapoff -a\n"