blob: 586e34a18eb448d4b6cef4789e7614ee88138ce6 [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 */
11
Denys Vlasenkob9f2d9f2011-01-18 13:58:01 +010012//applet:IF_INIT(APPLET(init, BB_DIR_SBIN, BB_SUID_DROP))
13//applet:IF_FEATURE_INITRD(APPLET_ODDNAME(linuxrc, init, BB_DIR_ROOT, BB_SUID_DROP, linuxrc))
Denys Vlasenkob1db09b2010-10-12 13:47:15 +020014
15//kbuild:lib-$(CONFIG_INIT) += init.o
16
17//config:config INIT
18//config: bool "init"
19//config: default y
20//config: select FEATURE_SYSLOG
21//config: help
22//config: init is the first program run when the system boots.
23//config:
24//config:config FEATURE_USE_INITTAB
25//config: bool "Support reading an inittab file"
26//config: default y
27//config: depends on INIT
28//config: help
29//config: Allow init to read an inittab file when the system boot.
30//config:
31//config:config FEATURE_KILL_REMOVED
32//config: bool "Support killing processes that have been removed from inittab"
33//config: default n
34//config: depends on FEATURE_USE_INITTAB
35//config: help
36//config: When respawn entries are removed from inittab and a SIGHUP is
37//config: sent to init, this option will make init kill the processes
38//config: that have been removed.
39//config:
40//config:config FEATURE_KILL_DELAY
41//config: int "How long to wait between TERM and KILL (0 - send TERM only)" if FEATURE_KILL_REMOVED
42//config: range 0 1024
43//config: default 0
44//config: depends on FEATURE_KILL_REMOVED
45//config: help
46//config: With nonzero setting, init sends TERM, forks, child waits N
47//config: seconds, sends KILL and exits. Setting it too high is unwise
48//config: (child will hang around for too long and could actually kill
49//config: the wrong process!)
50//config:
51//config:config FEATURE_INIT_SCTTY
52//config: bool "Run commands with leading dash with controlling tty"
53//config: default y
54//config: depends on INIT
55//config: help
56//config: If this option is enabled, init will try to give a controlling
57//config: tty to any command which has leading hyphen (often it's "-/bin/sh").
58//config: More precisely, init will do "ioctl(STDIN_FILENO, TIOCSCTTY, 0)".
59//config: If device attached to STDIN_FILENO can be a ctty but is not yet
60//config: a ctty for other session, it will become this process' ctty.
61//config: This is not the traditional init behavour, but is often what you want
62//config: in an embedded system where the console is only accessed during
63//config: development or for maintenance.
64//config: NB: using cttyhack applet may work better.
65//config:
66//config:config FEATURE_INIT_SYSLOG
67//config: bool "Enable init to write to syslog"
68//config: default y
69//config: depends on INIT
70//config:
71//config:config FEATURE_EXTRA_QUIET
72//config: bool "Be _extra_ quiet on boot"
73//config: default y
74//config: depends on INIT
75//config: help
76//config: Prevent init from logging some messages to the console during boot.
77//config:
78//config:config FEATURE_INIT_COREDUMPS
79//config: bool "Support dumping core for child processes (debugging only)"
80//config: default y
81//config: depends on INIT
82//config: help
83//config: If this option is enabled and the file /.init_enable_core
84//config: exists, then init will call setrlimit() to allow unlimited
85//config: core file sizes. If this option is disabled, processes
86//config: will not generate any core files.
87//config:
88//config:config FEATURE_INITRD
89//config: bool "Support running init from within an initrd (not initramfs)"
90//config: default y
91//config: depends on INIT
92//config: help
93//config: Legacy support for running init under the old-style initrd. Allows
94//config: the name linuxrc to act as init, and it doesn't assume init is PID 1.
95//config:
96//config: This does not apply to initramfs, which runs /init as PID 1 and
97//config: requires no special support.
98//config:
99//config:config INIT_TERMINAL_TYPE
100//config: string "Initial terminal type"
101//config: default "linux"
102//config: depends on INIT
103//config: help
104//config: This is the initial value set by init for the TERM environment
105//config: variable. This variable is used by programs which make use of
106//config: extended terminal capabilities.
107//config:
108//config: Note that on Linux, init attempts to detect serial terminal and
109//config: sets TERM to "vt102" if one is found.
110
Denis Vlasenkob6adbf12007-05-26 19:00:18 +0000111#include "libbb.h"
Bernhard Reutner-Fischerf4701962008-01-27 12:50:12 +0000112#include <syslog.h>
Eric Andersenb186d981999-12-03 09:19:54 +0000113#include <paths.h>
Denis Vlasenko6c622462009-01-29 02:01:04 +0000114#include <sys/resource.h>
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200115#ifdef __linux__
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000116#include <linux/vt.h>
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200117#endif
Jeremie Koenig714674e2010-05-27 15:38:44 +0200118#include "reboot.h" /* reboot() constants */
Eric Andersen2c1de612003-04-24 11:41:28 +0000119
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200120/* Used only for sanitizing purposes in set_sane_term() below. On systems where
121 * the baud rate is stored in a separate field, we can safely disable them. */
122#ifndef CBAUD
123# define CBAUD 0
124# define CBAUDEX 0
125#endif
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000126
Denis Vlasenko5cb54b52008-10-21 17:14:26 +0000127/* Was a CONFIG_xxx option. A lot of people were building
128 * not fully functional init by switching it on! */
129#define DEBUG_INIT 0
130
Denis Vlasenko6c622462009-01-29 02:01:04 +0000131#define COMMAND_SIZE 256
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000132#define CONSOLE_NAME_SIZE 32
Eric Andersenbd22ed82000-07-08 18:55:24 +0000133
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000134/* Default sysinit script. */
Erik Andersen96e2abd2000-01-07 11:40:44 +0000135#ifndef INIT_SCRIPT
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000136#define INIT_SCRIPT "/etc/init.d/rcS"
Erik Andersen96e2abd2000-01-07 11:40:44 +0000137#endif
Erik Andersen9c88cac1999-12-30 09:25:17 +0000138
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000139/* Each type of actions can appear many times. They will be
140 * handled in order. RESTART is an exception, only 1st is used.
141 */
142/* Start these actions first and wait for completion */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000143#define SYSINIT 0x01
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000144/* Start these after SYSINIT and wait for completion */
145#define WAIT 0x02
146/* Start these after WAIT and *dont* wait for completion */
147#define ONCE 0x04
148/*
149 * NB: while SYSINIT/WAIT/ONCE are being processed,
Denys Vlasenko6e542492009-11-15 03:07:19 +0100150 * SIGHUP ("reread /etc/inittab") will be processed only after
151 * each group of actions. If new inittab adds, say, a SYSINIT action,
152 * it will not be run, since init is already "past SYSINIT stage".
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000153 */
154/* Start these after ONCE are started, restart on exit */
155#define RESPAWN 0x08
156/* Like RESPAWN, but wait for <Enter> to be pressed on tty */
157#define ASKFIRST 0x10
158/*
159 * Start these on SIGINT, and wait for completion.
160 * Then go back to respawning RESPAWN and ASKFIRST actions.
161 * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
162 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000163#define CTRLALTDEL 0x20
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000164/*
165 * Start these before killing all processes in preparation for
166 * running RESTART actions or doing low-level halt/reboot/poweroff
167 * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
168 * Wait for completion before proceeding.
169 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000170#define SHUTDOWN 0x40
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000171/*
172 * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
173 * then all processes are killed, then init exec's 1st RESTART action,
174 * replacing itself by it. If no RESTART action specified,
175 * SIGQUIT has no effect.
176 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000177#define RESTART 0x80
Erik Andersen7dc16072000-01-04 01:10:25 +0000178
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000179
180/* A linked list of init_actions, to be read from inittab */
Eric Andersen0298be82002-03-05 15:12:19 +0000181struct init_action {
Eric Andersen0298be82002-03-05 15:12:19 +0000182 struct init_action *next;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000183 pid_t pid;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000184 uint8_t action_type;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000185 char terminal[CONSOLE_NAME_SIZE];
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000186 char command[COMMAND_SIZE];
Erik Andersen7dc16072000-01-04 01:10:25 +0000187};
Erik Andersen7dc16072000-01-04 01:10:25 +0000188
Eric Andersen0298be82002-03-05 15:12:19 +0000189static struct init_action *init_action_list = NULL;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000190
Denis Vlasenko4c978632007-02-03 03:31:13 +0000191static const char *log_console = VC_5;
Rob Landleybc68cd12006-03-10 19:22:06 +0000192
193enum {
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000194 L_LOG = 0x1,
195 L_CONSOLE = 0x2,
Rob Landleybc68cd12006-03-10 19:22:06 +0000196};
Erik Andersen42094cd2000-03-20 21:34:52 +0000197
Erik Andersen42094cd2000-03-20 21:34:52 +0000198/* Print a message to the specified device.
Denis Vlasenko671ca332008-02-19 14:13:20 +0000199 * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
200 * NB: careful, we can be called after vfork!
201 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000202#define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
Denis Vlasenko671ca332008-02-19 14:13:20 +0000203static void message(int where, const char *fmt, ...)
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000204 __attribute__ ((format(printf, 2, 3)));
Denis Vlasenko671ca332008-02-19 14:13:20 +0000205static void message(int where, const char *fmt, ...)
Eric Andersen0460ff21999-10-25 23:32:44 +0000206{
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000207 va_list arguments;
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000208 unsigned l;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000209 char msg[128];
210
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000211 msg[0] = '\r';
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000212 va_start(arguments, fmt);
Denis Vlasenko1bcdcd22008-12-09 21:23:31 +0000213 l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
214 if (l > sizeof(msg) - 1)
215 l = sizeof(msg) - 1;
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000216 va_end(arguments);
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000217
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000218#if ENABLE_FEATURE_INIT_SYSLOG
219 msg[l] = '\0';
220 if (where & L_LOG) {
221 /* Log the message to syslogd */
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100222 openlog(applet_name, 0, LOG_DAEMON);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000223 /* don't print "\r" */
224 syslog(LOG_INFO, "%s", msg + 1);
225 closelog();
226 }
227 msg[l++] = '\n';
228 msg[l] = '\0';
229#else
230 {
231 static int log_fd = -1;
232
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000233 msg[l++] = '\n';
234 msg[l] = '\0';
235 /* Take full control of the log tty, and never close it.
236 * It's mine, all mine! Muhahahaha! */
237 if (log_fd < 0) {
238 if (!log_console) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000239 log_fd = STDERR_FILENO;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000240 } else {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000241 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
242 if (log_fd < 0) {
243 bb_error_msg("can't log to %s", log_console);
Denis Vlasenko671ca332008-02-19 14:13:20 +0000244 where = L_CONSOLE;
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000245 } else {
246 close_on_exec_on(log_fd);
247 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000248 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000249 }
Denis Vlasenko671ca332008-02-19 14:13:20 +0000250 if (where & L_LOG) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000251 full_write(log_fd, msg, l);
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000252 if (log_fd == STDERR_FILENO)
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000253 return; /* don't print dup messages */
254 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000255 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000256#endif
Eric Andersen4c781471999-11-26 08:12:56 +0000257
Denis Vlasenko671ca332008-02-19 14:13:20 +0000258 if (where & L_CONSOLE) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000259 /* Send console messages to console so people will see them. */
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000260 full_write(STDERR_FILENO, msg, l);
Eric Andersen3ae0c781999-11-04 01:13:21 +0000261 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000262}
263
Eric Andersen74400cc2001-10-18 04:11:39 +0000264static void console_init(void)
Eric Andersen0460ff21999-10-25 23:32:44 +0000265{
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200266#ifdef VT_OPENQRY
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000267 int vtno;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200268#endif
Erik Andersene49d5ec2000-02-08 19:58:47 +0000269 char *s;
Eric Andersen0460ff21999-10-25 23:32:44 +0000270
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000271 s = getenv("CONSOLE");
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000272 if (!s)
273 s = getenv("console");
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000274 if (s) {
275 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
276 if (fd >= 0) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000277 dup2(fd, STDIN_FILENO);
278 dup2(fd, STDOUT_FILENO);
279 xmove_fd(fd, STDERR_FILENO);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000280 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000281 dbg_message(L_LOG, "console='%s'", s);
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000282 } else {
Denis Vlasenkofb274df2008-03-17 13:26:51 +0000283 /* Make sure fd 0,1,2 are not closed
284 * (so that they won't be used by future opens) */
Denis Vlasenkod48e81f2008-07-06 07:00:11 +0000285 bb_sanitize_stdio();
Denis Vlasenkoa34b8a42008-11-29 23:14:37 +0000286// Users report problems
287// /* Make sure init can't be blocked by writing to stderr */
288// fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
Eric Andersen07e52971999-11-07 07:38:08 +0000289 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000290
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000291 s = getenv("TERM");
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200292#ifdef VT_OPENQRY
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000293 if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) {
294 /* Not a linux terminal, probably serial console.
295 * Force the TERM setting to vt102
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000296 * if TERM is set to linux (the default) */
297 if (!s || strcmp(s, "linux") == 0)
298 putenv((char*)"TERM=vt102");
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000299 if (!ENABLE_FEATURE_INIT_SYSLOG)
300 log_console = NULL;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200301 } else
302#endif
303 if (!s)
Jeremie Koenig1c053032010-05-27 15:46:07 +0200304 putenv((char*)"TERM=" CONFIG_INIT_TERMINAL_TYPE);
Eric Andersen0460ff21999-10-25 23:32:44 +0000305}
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000306
Denis Vlasenko671ca332008-02-19 14:13:20 +0000307/* Set terminal settings to reasonable defaults.
308 * NB: careful, we can be called after vfork! */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000309static void set_sane_term(void)
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000310{
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000311 struct termios tty;
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000312
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000313 tcgetattr(STDIN_FILENO, &tty);
314
315 /* set control chars */
316 tty.c_cc[VINTR] = 3; /* C-c */
317 tty.c_cc[VQUIT] = 28; /* C-\ */
318 tty.c_cc[VERASE] = 127; /* C-? */
319 tty.c_cc[VKILL] = 21; /* C-u */
320 tty.c_cc[VEOF] = 4; /* C-d */
321 tty.c_cc[VSTART] = 17; /* C-q */
322 tty.c_cc[VSTOP] = 19; /* C-s */
323 tty.c_cc[VSUSP] = 26; /* C-z */
324
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200325#ifdef __linux__
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000326 /* use line discipline 0 */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000327 tty.c_line = 0;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200328#endif
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000329
330 /* Make it be sane */
Denys Vlasenkof2657a92010-10-24 02:04:10 +0200331#ifndef CRTSCTS
332# define CRTSCTS 0
333#endif
334 /* added CRTSCTS to fix Debian bug 528560 */
335 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD | CRTSCTS;
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000336 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
337
338 /* input modes */
339 tty.c_iflag = ICRNL | IXON | IXOFF;
340
341 /* output modes */
342 tty.c_oflag = OPOST | ONLCR;
343
344 /* local modes */
Denys Vlasenkof2657a92010-10-24 02:04:10 +0200345 tty.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000346
Denis Vlasenko202ac502008-11-05 13:20:58 +0000347 tcsetattr_stdin_TCSANOW(&tty);
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000348}
349
Denis Vlasenko671ca332008-02-19 14:13:20 +0000350/* Open the new terminal device.
351 * NB: careful, we can be called after vfork! */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000352static int open_stdio_to_tty(const char* tty_name)
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000353{
354 /* empty tty_name means "use init's tty", else... */
355 if (tty_name[0]) {
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000356 int fd;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000357
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000358 close(STDIN_FILENO);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000359 /* fd can be only < 0 or 0: */
360 fd = device_open(tty_name, O_RDWR);
361 if (fd) {
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000362 message(L_LOG | L_CONSOLE, "can't open %s: %s",
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000363 tty_name, strerror(errno));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000364 return 0; /* failure */
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000365 }
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000366 dup2(STDIN_FILENO, STDOUT_FILENO);
367 dup2(STDIN_FILENO, STDERR_FILENO);
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000368 }
Denis Vlasenkod238a472007-03-05 19:22:04 +0000369 set_sane_term();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000370 return 1; /* success */
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000371}
372
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100373static void reset_sighandlers_and_unblock_sigs(void)
374{
375 bb_signals(0
376 + (1 << SIGUSR1)
377 + (1 << SIGUSR2)
378 + (1 << SIGTERM)
379 + (1 << SIGQUIT)
380 + (1 << SIGINT)
381 + (1 << SIGHUP)
382 + (1 << SIGTSTP)
Denys Vlasenko18f89122009-12-14 03:08:30 +0100383 + (1 << SIGSTOP)
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100384 , SIG_DFL);
385 sigprocmask_allsigs(SIG_UNBLOCK);
386}
387
Denis Vlasenko671ca332008-02-19 14:13:20 +0000388/* Wrapper around exec:
389 * Takes string (max COMMAND_SIZE chars).
390 * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
391 * Otherwise splits words on whitespace, deals with leading dash,
392 * and uses plain exec().
393 * NB: careful, we can be called after vfork!
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000394 */
395static void init_exec(const char *command)
396{
397 char *cmd[COMMAND_SIZE / 2];
398 char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000399 int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000400
Denys Vlasenko6088e132010-12-25 23:58:42 +0100401 command += dash;
402
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000403 /* See if any special /bin/sh requiring characters are present */
404 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
Denys Vlasenko6088e132010-12-25 23:58:42 +0100405 sprintf(buf, "exec %s", command); /* excluding "-" */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000406 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000407 cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
408 cmd[1] = (char*)"-c";
409 cmd[2] = buf;
410 cmd[3] = NULL;
Denys Vlasenko6088e132010-12-25 23:58:42 +0100411 command = LIBBB_DEFAULT_LOGIN_SHELL + 1;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000412 } else {
413 /* Convert command (char*) into cmd (char**, one word per string) */
414 char *word, *next;
415 int i = 0;
Denys Vlasenko6088e132010-12-25 23:58:42 +0100416 next = strcpy(buf, command - dash); /* command including "-" */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000417 while ((word = strsep(&next, " \t")) != NULL) {
418 if (*word != '\0') { /* not two spaces/tabs together? */
419 cmd[i] = word;
420 i++;
421 }
422 }
423 cmd[i] = NULL;
424 }
425 /* If we saw leading "-", it is interactive shell.
426 * Try harder to give it a controlling tty.
Denys Vlasenko6088e132010-12-25 23:58:42 +0100427 */
428 if (ENABLE_FEATURE_INIT_SCTTY && dash) {
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000429 /* _Attempt_ to make stdin a controlling tty. */
Denys Vlasenko6088e132010-12-25 23:58:42 +0100430 ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000431 }
Denys Vlasenko6088e132010-12-25 23:58:42 +0100432 /* Here command never contains the dash, cmd[0] might */
433 BB_EXECVP(command, cmd);
434 message(L_LOG | L_CONSOLE, "can't run '%s': %s", command, strerror(errno));
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000435 /* returns if execvp fails */
436}
437
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000438/* Used only by run_actions */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000439static pid_t run(const struct init_action *a)
Eric Andersen0298be82002-03-05 15:12:19 +0000440{
Mike Frysinger10427ab2005-07-06 05:00:48 +0000441 pid_t pid;
Erik Andersenac6e71f2000-01-08 22:04:33 +0000442
Denis Vlasenko47741792009-03-10 16:01:57 +0000443 /* Careful: don't be affected by a signal in vforked child */
444 sigprocmask_allsigs(SIG_BLOCK);
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000445 if (BB_MMU && (a->action_type & ASKFIRST))
446 pid = fork();
447 else
448 pid = vfork();
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000449 if (pid < 0)
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000450 message(L_LOG | L_CONSOLE, "can't fork");
Denis Vlasenko47741792009-03-10 16:01:57 +0000451 if (pid) {
452 sigprocmask_allsigs(SIG_UNBLOCK);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000453 return pid; /* Parent or error */
Denis Vlasenko47741792009-03-10 16:01:57 +0000454 }
Eric Andersen0298be82002-03-05 15:12:19 +0000455
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000456 /* Child */
457
Denis Vlasenko966bb432007-02-27 19:20:33 +0000458 /* Reset signal handlers that were set by the parent process */
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100459 reset_sighandlers_and_unblock_sigs();
Eric Andersen2f6c04f1999-11-01 23:59:44 +0000460
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000461 /* Create a new session and make ourself the process group leader */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000462 setsid();
Eric Andersen599e3ce2002-07-03 11:08:10 +0000463
Denis Vlasenko966bb432007-02-27 19:20:33 +0000464 /* Open the new terminal device */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000465 if (!open_stdio_to_tty(a->terminal))
466 _exit(EXIT_FAILURE);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000467
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000468 /* NB: on NOMMU we can't wait for input in child, so
469 * "askfirst" will work the same as "respawn". */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000470 if (BB_MMU && (a->action_type & ASKFIRST)) {
Denis Vlasenko6ca409e2007-08-12 20:58:27 +0000471 static const char press_enter[] ALIGN1 =
Denis Vlasenko966bb432007-02-27 19:20:33 +0000472#ifdef CUSTOMIZED_BANNER
473#include CUSTOMIZED_BANNER
Eric Andersen1f50e842004-08-16 09:29:42 +0000474#endif
Denis Vlasenko966bb432007-02-27 19:20:33 +0000475 "\nPlease press Enter to activate this console. ";
476 char c;
477 /*
478 * Save memory by not exec-ing anything large (like a shell)
479 * before the user wants it. This is critical if swap is not
480 * enabled and the system has low memory. Generally this will
481 * be run on the second virtual console, and the first will
482 * be allowed to start a shell or whatever an init script
483 * specifies.
484 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000485 dbg_message(L_LOG, "waiting for enter to start '%s'"
Denis Vlasenko966bb432007-02-27 19:20:33 +0000486 "(pid %d, tty '%s')\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000487 a->command, getpid(), a->terminal);
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000488 full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
489 while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000490 continue;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000491 }
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000492
Denis Vlasenko6c622462009-01-29 02:01:04 +0000493 /*
494 * When a file named /.init_enable_core exists, setrlimit is called
495 * before processes are spawned to set core file size as unlimited.
496 * This is for debugging only. Don't use this is production, unless
497 * you want core dumps lying about....
498 */
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000499 if (ENABLE_FEATURE_INIT_COREDUMPS) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000500 if (access("/.init_enable_core", F_OK) == 0) {
Denis Vlasenko966bb432007-02-27 19:20:33 +0000501 struct rlimit limit;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000502 limit.rlim_cur = RLIM_INFINITY;
503 limit.rlim_max = RLIM_INFINITY;
504 setrlimit(RLIMIT_CORE, &limit);
Erik Andersen983b51b2000-04-04 18:14:25 +0000505 }
Erik Andersen05df2392000-01-13 04:43:48 +0000506 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000507
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000508 /* Log the process name and args */
509 message(L_LOG, "starting pid %d, tty '%s': '%s'",
510 getpid(), a->terminal, a->command);
511
Denis Vlasenko966bb432007-02-27 19:20:33 +0000512 /* Now run it. The new program will take over this PID,
513 * so nothing further in init.c should be run. */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000514 init_exec(a->command);
Denis Vlasenko966bb432007-02-27 19:20:33 +0000515 /* We're still here? Some error happened. */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000516 _exit(-1);
Eric Andersen0460ff21999-10-25 23:32:44 +0000517}
518
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000519static struct init_action *mark_terminated(pid_t pid)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000520{
521 struct init_action *a;
522
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000523 if (pid > 0) {
524 for (a = init_action_list; a; a = a->next) {
525 if (a->pid == pid) {
526 a->pid = 0;
527 return a;
528 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000529 }
Denys Vlasenko3b060522010-10-25 00:40:32 +0200530 update_utmp(pid, DEAD_PROCESS, /*tty_name:*/ NULL,
531 /*username:*/ NULL,
532 /*hostname:*/ NULL);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000533 }
534 return NULL;
535}
536
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000537static void waitfor(pid_t pid)
538{
539 /* waitfor(run(x)): protect against failed fork inside run() */
540 if (pid <= 0)
541 return;
542
543 /* Wait for any child (prevent zombies from exiting orphaned processes)
544 * but exit the loop only when specified one has exited. */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000545 while (1) {
546 pid_t wpid = wait(NULL);
547 mark_terminated(wpid);
548 /* Unsafe. SIGTSTP handler might have wait'ed it already */
549 /*if (wpid == pid) break;*/
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000550 /* More reliable: */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000551 if (kill(pid, 0))
552 break;
553 }
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000554}
555
Eric Andersen0298be82002-03-05 15:12:19 +0000556/* Run all commands of a particular type */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000557static void run_actions(int action_type)
Eric Andersen219d6f51999-11-02 19:43:01 +0000558{
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000559 struct init_action *a;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000560
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000561 for (a = init_action_list; a; a = a->next) {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000562 if (!(a->action_type & action_type))
563 continue;
Eric Andersen5222d312002-07-03 05:15:23 +0000564
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000565 if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
566 pid_t pid = run(a);
567 if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
568 waitfor(pid);
569 }
570 if (a->action_type & (RESPAWN | ASKFIRST)) {
571 /* Only run stuff with pid == 0. If pid != 0,
572 * it is already running
573 */
574 if (a->pid == 0)
575 a->pid = run(a);
Eric Andersen730f8262001-12-17 23:13:08 +0000576 }
577 }
578}
579
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000580static void new_init_action(uint8_t action_type, const char *command, const char *cons)
Erik Andersen7dc16072000-01-04 01:10:25 +0000581{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000582 struct init_action *a, **nextp;
Erik Andersen9e737252000-01-06 01:16:13 +0000583
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000584 /* Scenario:
585 * old inittab:
586 * ::shutdown:umount -a -r
587 * ::shutdown:swapoff -a
588 * new inittab:
589 * ::shutdown:swapoff -a
590 * ::shutdown:umount -a -r
591 * On reload, we must ensure entries end up in correct order.
592 * To achieve that, if we find a matching entry, we move it
593 * to the end.
594 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000595 nextp = &init_action_list;
596 while ((a = *nextp) != NULL) {
597 /* Don't enter action if it's already in the list,
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000598 * This prevents losing running RESPAWNs.
599 */
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100600 if (strcmp(a->command, command) == 0
601 && strcmp(a->terminal, cons) == 0
Denis Vlasenkob74a2db2008-07-21 21:34:51 +0000602 ) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000603 /* Remove from list */
604 *nextp = a->next;
605 /* Find the end of the list */
606 while (*nextp != NULL)
607 nextp = &(*nextp)->next;
608 a->next = NULL;
609 break;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000610 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000611 nextp = &a->next;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000612 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000613
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000614 if (!a)
615 a = xzalloc(sizeof(*a));
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000616 /* Append to the end of the list */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000617 *nextp = a;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000618 a->action_type = action_type;
619 safe_strncpy(a->command, command, sizeof(a->command));
620 safe_strncpy(a->terminal, cons, sizeof(a->terminal));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000621 dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000622 a->command, a->action_type, a->terminal);
Erik Andersen7dc16072000-01-04 01:10:25 +0000623}
624
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000625/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersen9e737252000-01-06 01:16:13 +0000626 * then parse_inittab() simply adds in some default
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000627 * actions(i.e., runs INIT_SCRIPT and then starts a pair
628 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
629 * _is_ defined, but /etc/inittab is missing, this
Erik Andersen812d4662000-01-07 18:30:40 +0000630 * results in the same set of default behaviors.
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000631 */
Eric Andersen3e6ff902001-03-09 21:24:12 +0000632static void parse_inittab(void)
Erik Andersen7dc16072000-01-04 01:10:25 +0000633{
Denis Vlasenko6c622462009-01-29 02:01:04 +0000634#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000635 char *token[4];
Denis Vlasenko6c622462009-01-29 02:01:04 +0000636 parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000637
Denis Vlasenko6c622462009-01-29 02:01:04 +0000638 if (parser == NULL)
639#endif
640 {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000641 /* No inittab file - set up some default behavior */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000642 /* Reboot on Ctrl-Alt-Del */
643 new_init_action(CTRLALTDEL, "reboot", "");
644 /* Umount all filesystems on halt/reboot */
645 new_init_action(SHUTDOWN, "umount -a -r", "");
646 /* Swapoff on halt/reboot */
647 if (ENABLE_SWAPONOFF)
648 new_init_action(SHUTDOWN, "swapoff -a", "");
649 /* Prepare to restart init when a QUIT is received */
650 new_init_action(RESTART, "init", "");
651 /* Askfirst shell on tty1-4 */
652 new_init_action(ASKFIRST, bb_default_login_shell, "");
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000653//TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000654 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
655 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
656 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
657 /* sysinit */
658 new_init_action(SYSINIT, INIT_SCRIPT, "");
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000659 return;
660 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000661
662#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000663 /* optional_tty:ignored_runlevel:action:command
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000664 * Delims are not to be collapsed and need exactly 4 tokens
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000665 */
Denis Vlasenko084266e2008-07-26 23:08:31 +0000666 while (config_read(parser, token, 4, 0, "#:",
667 PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000668 /* order must correspond to SYSINIT..RESTART constants */
669 static const char actions[] ALIGN1 =
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000670 "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
Denis Vlasenko6c622462009-01-29 02:01:04 +0000671 "ctrlaltdel\0""shutdown\0""restart\0";
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000672 int action;
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000673 char *tty = token[0];
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000674
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000675 if (!token[3]) /* less than 4 tokens */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000676 goto bad_entry;
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000677 action = index_in_strings(actions, token[2]);
678 if (action < 0 || !token[3][0]) /* token[3]: command */
679 goto bad_entry;
680 /* turn .*TTY -> /dev/TTY */
681 if (tty[0]) {
Denys Vlasenkof8d8aa12010-04-06 18:50:05 +0200682 tty = concat_path_file("/dev/", skip_dev_pfx(tty));
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000683 }
684 new_init_action(1 << action, token[3], tty);
685 if (tty[0])
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000686 free(tty);
687 continue;
688 bad_entry:
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000689 message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
690 parser->lineno);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000691 }
692 config_close(parser);
Denis Vlasenko6c622462009-01-29 02:01:04 +0000693#endif
Erik Andersen7dc16072000-01-04 01:10:25 +0000694}
695
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000696static void pause_and_low_level_reboot(unsigned magic) NORETURN;
697static void pause_and_low_level_reboot(unsigned magic)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000698{
699 pid_t pid;
700
701 /* Allow time for last message to reach serial console, etc */
702 sleep(1);
703
704 /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
705 * in linux/kernel/sys.c, which can cause the machine to panic when
706 * the init process exits... */
707 pid = vfork();
708 if (pid == 0) { /* child */
709 reboot(magic);
710 _exit(EXIT_SUCCESS);
711 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000712 while (1)
713 sleep(1);
714}
715
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000716static void run_shutdown_and_kill_processes(void)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000717{
718 /* Run everything to be run at "shutdown". This is done _prior_
719 * to killing everything, in case people wish to use scripts to
720 * shut things down gracefully... */
721 run_actions(SHUTDOWN);
722
723 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
724
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000725 /* Send signals to every process _except_ pid 1 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000726 kill(-1, SIGTERM);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000727 message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000728 sync();
729 sleep(1);
730
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000731 kill(-1, SIGKILL);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000732 message(L_CONSOLE, "Sent SIG%s to all processes", "KILL");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000733 sync();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000734 /*sleep(1); - callers take care about making a pause */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000735}
736
737/* Signal handling by init:
738 *
739 * For process with PID==1, on entry kernel sets all signals to SIG_DFL
740 * and unmasks all signals. However, for process with PID==1,
741 * default action (SIG_DFL) on any signal is to ignore it,
742 * even for special signals SIGKILL and SIGCONT.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000743 * Also, any signal can be caught or blocked.
Denis Vlasenkofc2a4fc2009-01-31 01:07:05 +0000744 * (but SIGSTOP is still handled specially, at least in 2.6.20)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000745 *
746 * We install two kinds of handlers, "immediate" and "delayed".
747 *
748 * Immediate handlers execute at any time, even while, say, sysinit
749 * is running.
750 *
751 * Delayed handlers just set a flag variable. The variable is checked
752 * in the main loop and acted upon.
753 *
754 * halt/poweroff/reboot and restart have immediate handlers.
755 * They only traverse linked list of struct action's, never modify it,
756 * this should be safe to do even in signal handler. Also they
757 * never return.
758 *
759 * SIGSTOP and SIGTSTP have immediate handlers. They just wait
760 * for SIGCONT to happen.
761 *
762 * SIGHUP has a delayed handler, because modifying linked list
763 * of struct action's from a signal handler while it is manipulated
764 * by the program may be disastrous.
765 *
766 * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
767 * it to happen even somewhere inside "sysinit" would be a bit awkward.
768 *
769 * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
Denis Vlasenko93b38202009-02-14 20:58:13 +0000770 * and only one will be remembered and acted upon.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000771 */
772
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100773/* The SIGUSR[12]/SIGTERM handler */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000774static void halt_reboot_pwoff(int sig) NORETURN;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000775static void halt_reboot_pwoff(int sig)
776{
777 const char *m;
778 unsigned rb;
779
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100780 /* We may call run() and it unmasks signals,
781 * including the one masked inside this signal handler.
782 * Testcase which would start multiple reboot scripts:
783 * while true; do reboot; done
784 * Preventing it:
785 */
786 reset_sighandlers_and_unblock_sigs();
787
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000788 run_shutdown_and_kill_processes();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000789
790 m = "halt";
791 rb = RB_HALT_SYSTEM;
792 if (sig == SIGTERM) {
793 m = "reboot";
794 rb = RB_AUTOBOOT;
795 } else if (sig == SIGUSR2) {
796 m = "poweroff";
797 rb = RB_POWER_OFF;
798 }
799 message(L_CONSOLE, "Requesting system %s", m);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000800 pause_and_low_level_reboot(rb);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000801 /* not reached */
802}
803
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100804/* Handler for QUIT - exec "restart" action,
805 * else (no such action defined) do nothing */
806static void restart_handler(int sig UNUSED_PARAM)
807{
808 struct init_action *a;
809
810 for (a = init_action_list; a; a = a->next) {
811 if (!(a->action_type & RESTART))
812 continue;
813
814 /* Starting from here, we won't return.
815 * Thus don't need to worry about preserving errno
816 * and such.
817 */
818
819 reset_sighandlers_and_unblock_sigs();
820
821 run_shutdown_and_kill_processes();
822
Jeremie Koenig714674e2010-05-27 15:38:44 +0200823#ifdef RB_ENABLE_CAD
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100824 /* Allow Ctrl-Alt-Del to reboot the system.
825 * This is how kernel sets it up for init, we follow suit.
826 */
827 reboot(RB_ENABLE_CAD); /* misnomer */
Jeremie Koenig714674e2010-05-27 15:38:44 +0200828#endif
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100829
830 if (open_stdio_to_tty(a->terminal)) {
831 dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
832 /* Theoretically should be safe.
833 * But in practice, kernel bugs may leave
834 * unkillable processes, and wait() may block forever.
835 * Oh well. Hoping "new" init won't be too surprised
836 * by having children it didn't create.
837 */
838 //while (wait(NULL) > 0)
839 // continue;
840 init_exec(a->command);
841 }
842 /* Open or exec failed */
843 pause_and_low_level_reboot(RB_HALT_SYSTEM);
844 /* not reached */
845 }
846}
847
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000848/* The SIGSTOP/SIGTSTP handler
849 * NB: inside it, all signals except SIGCONT are masked
850 * via appropriate setup in sigaction().
851 */
852static void stop_handler(int sig UNUSED_PARAM)
853{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000854 smallint saved_bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000855 int saved_errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000856
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000857 saved_bb_got_signal = bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000858 saved_errno = errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000859 signal(SIGCONT, record_signo);
860
861 while (1) {
862 pid_t wpid;
863
864 if (bb_got_signal == SIGCONT)
865 break;
866 /* NB: this can accidentally wait() for a process
867 * which we waitfor() elsewhere! waitfor() must have
868 * code which is resilient against this.
869 */
870 wpid = wait_any_nohang(NULL);
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000871 mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000872 sleep(1);
873 }
874
875 signal(SIGCONT, SIG_DFL);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000876 errno = saved_errno;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000877 bb_got_signal = saved_bb_got_signal;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000878}
879
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000880#if ENABLE_FEATURE_USE_INITTAB
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000881static void reload_inittab(void)
Eric Andersen6fd0e312003-07-22 09:48:56 +0000882{
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000883 struct init_action *a, **nextp;
Eric Andersen82baf632004-10-08 08:21:54 +0000884
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000885 message(L_LOG, "reloading /etc/inittab");
Eric Andersen82baf632004-10-08 08:21:54 +0000886
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000887 /* Disable old entries */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000888 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100889 a->action_type = 0;
Eric Andersen82baf632004-10-08 08:21:54 +0000890
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000891 /* Append new entries, or modify existing entries
Denys Vlasenko6e542492009-11-15 03:07:19 +0100892 * (incl. setting a->action_type) if cmd and device name
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000893 * match new ones. End result: only entries with
Denys Vlasenko6e542492009-11-15 03:07:19 +0100894 * a->action_type == 0 are stale.
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000895 */
Eric Andersen82baf632004-10-08 08:21:54 +0000896 parse_inittab();
897
Denis Vlasenko93b38202009-02-14 20:58:13 +0000898#if ENABLE_FEATURE_KILL_REMOVED
899 /* Kill stale entries */
900 /* Be nice and send SIGTERM first */
901 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100902 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000903 kill(a->pid, SIGTERM);
904 if (CONFIG_FEATURE_KILL_DELAY) {
905 /* NB: parent will wait in NOMMU case */
906 if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
907 sleep(CONFIG_FEATURE_KILL_DELAY);
908 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100909 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000910 kill(a->pid, SIGKILL);
911 _exit(EXIT_SUCCESS);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000912 }
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000913 }
Denis Vlasenko93b38202009-02-14 20:58:13 +0000914#endif
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000915
Denys Vlasenko6e542492009-11-15 03:07:19 +0100916 /* Remove stale entries and SYSINIT entries.
917 * We never rerun SYSINIT entries anyway,
918 * removing them too saves a few bytes */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000919 nextp = &init_action_list;
920 while ((a = *nextp) != NULL) {
Denys Vlasenko6e542492009-11-15 03:07:19 +0100921 if ((a->action_type & ~SYSINIT) == 0) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000922 *nextp = a->next;
923 free(a);
924 } else {
925 nextp = &a->next;
926 }
Eric Andersen82baf632004-10-08 08:21:54 +0000927 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000928
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000929 /* Not needed: */
930 /* run_actions(RESPAWN | ASKFIRST); */
931 /* - we return to main loop, which does this automagically */
Eric Andersen6fd0e312003-07-22 09:48:56 +0000932}
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000933#endif
Eric Andersen82baf632004-10-08 08:21:54 +0000934
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000935static int check_delayed_sigs(void)
936{
937 int sigs_seen = 0;
938
939 while (1) {
940 smallint sig = bb_got_signal;
941
942 if (!sig)
943 return sigs_seen;
944 bb_got_signal = 0;
945 sigs_seen = 1;
946#if ENABLE_FEATURE_USE_INITTAB
947 if (sig == SIGHUP)
948 reload_inittab();
949#endif
950 if (sig == SIGINT)
951 run_actions(CTRLALTDEL);
952 }
953}
954
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000955int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000956int init_main(int argc UNUSED_PARAM, char **argv)
Eric Andersen0460ff21999-10-25 23:32:44 +0000957{
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100958 if (argv[1] && strcmp(argv[1], "-q") == 0) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000959 return kill(1, SIGHUP);
Eric Andersen730f8262001-12-17 23:13:08 +0000960 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000961
Denis Vlasenko5cb54b52008-10-21 17:14:26 +0000962 if (!DEBUG_INIT) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000963 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
964 if (getpid() != 1
Denys Vlasenkodb5fe622010-11-02 20:13:03 +0100965 && (!ENABLE_FEATURE_INITRD || applet_name[0] != 'l') /* not linuxrc? */
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000966 ) {
Denys Vlasenkodb5fe622010-11-02 20:13:03 +0100967 bb_error_msg_and_die("must be run as PID 1");
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000968 }
Jeremie Koenig714674e2010-05-27 15:38:44 +0200969#ifdef RB_DISABLE_CAD
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000970 /* Turn off rebooting via CTL-ALT-DEL - we get a
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000971 * SIGINT on CAD so we can shut things down gracefully... */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000972 reboot(RB_DISABLE_CAD); /* misnomer */
Jeremie Koenig714674e2010-05-27 15:38:44 +0200973#endif
Erik Andersene49d5ec2000-02-08 19:58:47 +0000974 }
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000975
Denys Vlasenko3b060522010-10-25 00:40:32 +0200976 /* If, say, xmalloc would ever die, we don't want to oops kernel
977 * by exiting.
978 * NB: we set die_sleep *after* PID 1 check and bb_show_usage.
979 * Otherwise, for example, "init u" ("please rexec yourself"
980 * command for sysvinit) will show help text (which isn't too bad),
981 * *and sleep forever* (which is bad!)
982 */
983 die_sleep = 30 * 24*60*60;
984
Eric Andersen599e3ce2002-07-03 11:08:10 +0000985 /* Figure out where the default console should be */
986 console_init();
Denis Vlasenkod238a472007-03-05 19:22:04 +0000987 set_sane_term();
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000988 xchdir("/");
Erik Andersene49d5ec2000-02-08 19:58:47 +0000989 setsid();
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000990
991 /* Make sure environs is set to something sane */
992 putenv((char *) "HOME=/");
993 putenv((char *) bb_PATH_root_path);
994 putenv((char *) "SHELL=/bin/sh");
995 putenv((char *) "USER=root"); /* needed? why? */
Rob Landleycba1b962006-07-09 17:28:17 +0000996
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000997 if (argv[1])
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000998 xsetenv("RUNLEVEL", argv[1]);
Rob Landleycba1b962006-07-09 17:28:17 +0000999
Denys Vlasenkod7171c12009-12-15 00:34:59 +01001000#if !ENABLE_FEATURE_EXTRA_QUIET
Erik Andersene49d5ec2000-02-08 19:58:47 +00001001 /* Hello world */
Denys Vlasenko6be918d2009-12-14 01:32:11 +01001002 message(L_CONSOLE | L_LOG, "init started: %s", bb_banner);
1003#endif
Eric Andersencc8ed391999-10-05 16:24:54 +00001004
Jeremie Koenig714674e2010-05-27 15:38:44 +02001005/* struct sysinfo is linux-specific */
1006#ifdef __linux__
Erik Andersene49d5ec2000-02-08 19:58:47 +00001007 /* Make sure there is enough memory to do something useful. */
Rob Landleyc3386a42005-08-30 18:50:37 +00001008 if (ENABLE_SWAPONOFF) {
1009 struct sysinfo info;
1010
Denis Vlasenko6c622462009-01-29 02:01:04 +00001011 if (sysinfo(&info) == 0
Denys Vlasenko90a99042009-09-06 02:36:23 +02001012 && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024
Denis Vlasenko6c622462009-01-29 02:01:04 +00001013 ) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +00001014 message(L_CONSOLE, "Low memory, forcing swapon");
Rob Landleyc3386a42005-08-30 18:50:37 +00001015 /* swapon -a requires /proc typically */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +00001016 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
Rob Landleyc3386a42005-08-30 18:50:37 +00001017 /* Try to turn on swap */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +00001018 new_init_action(SYSINIT, "swapon -a", "");
Rob Landleyc3386a42005-08-30 18:50:37 +00001019 run_actions(SYSINIT); /* wait and removing */
1020 }
1021 }
Jeremie Koenig714674e2010-05-27 15:38:44 +02001022#endif
Erik Andersen9e737252000-01-06 01:16:13 +00001023
Erik Andersene49d5ec2000-02-08 19:58:47 +00001024 /* Check if we are supposed to be in single user mode */
Denis Vlasenko1d426652008-03-17 09:09:09 +00001025 if (argv[1]
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +01001026 && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1'))
Denis Vlasenkobf66fbc2006-12-21 13:23:14 +00001027 ) {
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +00001028 /* ??? shouldn't we set RUNLEVEL="b" here? */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +00001029 /* Start a shell on console */
Glenn L McGrathdc4e75e2003-09-02 02:36:18 +00001030 new_init_action(RESPAWN, bb_default_login_shell, "");
Erik Andersene49d5ec2000-02-08 19:58:47 +00001031 } else {
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001032 /* Not in single user mode - see what inittab says */
Eric Andersen8a8fbb81999-10-26 00:18:56 +00001033
Eric Andersenbdfd0d72001-10-24 05:00:29 +00001034 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersene49d5ec2000-02-08 19:58:47 +00001035 * then parse_inittab() simply adds in some default
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001036 * actions(i.e., INIT_SCRIPT and a pair
Erik Andersene49d5ec2000-02-08 19:58:47 +00001037 * of "askfirst" shells */
1038 parse_inittab();
Eric Andersend00c2621999-12-07 08:37:31 +00001039 }
Erik Andersen983b51b2000-04-04 18:14:25 +00001040
Denis Vlasenko9b1381f2007-01-03 02:56:00 +00001041#if ENABLE_SELINUX
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001042 if (getenv("SELINUX_INIT") == NULL) {
1043 int enforce = 0;
1044
Denis Vlasenkod8540f72007-06-14 07:53:06 +00001045 putenv((char*)"SELINUX_INIT=YES");
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001046 if (selinux_init_load_policy(&enforce) == 0) {
Denis Vlasenko4921b542007-02-03 02:17:41 +00001047 BB_EXECVP(argv[0], argv);
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001048 } else if (enforce > 0) {
1049 /* SELinux in enforcing mode but load_policy failed */
Denys Vlasenko6331cf02009-11-13 09:08:27 +01001050 message(L_CONSOLE, "can't load SELinux Policy. "
Denis Vlasenkob7167542007-02-27 19:20:00 +00001051 "Machine is in enforcing mode. Halting now.");
Denys Vlasenko3b060522010-10-25 00:40:32 +02001052 return EXIT_FAILURE;
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001053 }
1054 }
Denis Vlasenko6c622462009-01-29 02:01:04 +00001055#endif
Rob Landleyb3ede5a2006-03-27 23:09:12 +00001056
Denis Vlasenko2afabe82007-12-10 07:06:04 +00001057 /* Make the command line just say "init" - thats all, nothing else */
1058 strncpy(argv[0], "init", strlen(argv[0]));
1059 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
1060 while (*++argv)
1061 memset(*argv, 0, strlen(*argv));
Eric Andersen219d6f51999-11-02 19:43:01 +00001062
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001063 /* Set up signal handlers */
1064 if (!DEBUG_INIT) {
1065 struct sigaction sa;
Erik Andersene49d5ec2000-02-08 19:58:47 +00001066
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001067 bb_signals(0
1068 + (1 << SIGUSR1) /* halt */
1069 + (1 << SIGTERM) /* reboot */
1070 + (1 << SIGUSR2) /* poweroff */
1071 , halt_reboot_pwoff);
1072 signal(SIGQUIT, restart_handler); /* re-exec another init */
1073
1074 /* Stop handler must allow only SIGCONT inside itself */
1075 memset(&sa, 0, sizeof(sa));
1076 sigfillset(&sa.sa_mask);
1077 sigdelset(&sa.sa_mask, SIGCONT);
1078 sa.sa_handler = stop_handler;
1079 /* NB: sa_flags doesn't have SA_RESTART.
1080 * It must be able to interrupt wait().
1081 */
1082 sigaction_set(SIGTSTP, &sa); /* pause */
1083 /* Does not work as intended, at least in 2.6.20.
1084 * SIGSTOP is simply ignored by init:
1085 */
1086 sigaction_set(SIGSTOP, &sa); /* pause */
1087
1088 /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
1089 * setting handler without SA_RESTART flag.
1090 */
1091 bb_signals_recursive_norestart((1 << SIGINT), record_signo);
1092 }
1093
Denys Vlasenko6e542492009-11-15 03:07:19 +01001094 /* Set up "reread /etc/inittab" handler.
1095 * Handler is set up without SA_RESTART, it will interrupt syscalls.
1096 */
1097 if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
1098 bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
1099
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001100 /* Now run everything that needs to be run */
Erik Andersene49d5ec2000-02-08 19:58:47 +00001101 /* First run the sysinit command */
Eric Andersen1644db92001-09-05 20:18:15 +00001102 run_actions(SYSINIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001103 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +00001104 /* Next run anything that wants to block */
Eric Andersen1644db92001-09-05 20:18:15 +00001105 run_actions(WAIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001106 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +00001107 /* Next run anything to be run only once */
Eric Andersen0298be82002-03-05 15:12:19 +00001108 run_actions(ONCE);
1109
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001110 /* Now run the looping stuff for the rest of forever.
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001111 */
Erik Andersene49d5ec2000-02-08 19:58:47 +00001112 while (1) {
Denis Vlasenko47741792009-03-10 16:01:57 +00001113 int maybe_WNOHANG;
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001114
Denis Vlasenko47741792009-03-10 16:01:57 +00001115 maybe_WNOHANG = check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001116
1117 /* (Re)run the respawn/askfirst stuff */
Denis Vlasenkoad4da982008-04-05 04:24:23 +00001118 run_actions(RESPAWN | ASKFIRST);
Denis Vlasenko47741792009-03-10 16:01:57 +00001119 maybe_WNOHANG |= check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001120
1121 /* Don't consume all CPU time - sleep a bit */
Eric Andersen0298be82002-03-05 15:12:19 +00001122 sleep(1);
Denis Vlasenko47741792009-03-10 16:01:57 +00001123 maybe_WNOHANG |= check_delayed_sigs();
Eric Andersen0298be82002-03-05 15:12:19 +00001124
Denis Vlasenko47741792009-03-10 16:01:57 +00001125 /* Wait for any child process(es) to exit.
Denys Vlasenko3ed181b2009-07-19 14:29:18 +02001126 *
1127 * If check_delayed_sigs above reported that a signal
1128 * was caught, wait will be nonblocking. This ensures
1129 * that if SIGHUP has reloaded inittab, respawn and askfirst
1130 * actions will not be delayed until next child death.
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001131 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001132 if (maybe_WNOHANG)
1133 maybe_WNOHANG = WNOHANG;
1134 while (1) {
1135 pid_t wpid;
1136 struct init_action *a;
1137
Denys Vlasenko3ed181b2009-07-19 14:29:18 +02001138 /* If signals happen _in_ the wait, they interrupt it,
1139 * bb_signals_recursive_norestart set them up that way
1140 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001141 wpid = waitpid(-1, NULL, maybe_WNOHANG);
1142 if (wpid <= 0)
1143 break;
1144
1145 a = mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001146 if (a) {
1147 message(L_LOG, "process '%s' (pid %d) exited. "
1148 "Scheduling for restart.",
1149 a->command, wpid);
Erik Andersene49d5ec2000-02-08 19:58:47 +00001150 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001151 /* See if anyone else is waiting to be reaped */
Denis Vlasenko47741792009-03-10 16:01:57 +00001152 maybe_WNOHANG = WNOHANG;
Erik Andersene49d5ec2000-02-08 19:58:47 +00001153 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001154 } /* while (1) */
Eric Andersencc8ed391999-10-05 16:24:54 +00001155}
Denys Vlasenkodb5fe622010-11-02 20:13:03 +01001156
1157//usage:#define linuxrc_trivial_usage NOUSAGE_STR
1158//usage:#define linuxrc_full_usage ""
1159
1160//usage:#define init_trivial_usage
1161//usage: ""
1162//usage:#define init_full_usage "\n\n"
1163//usage: "Init is the parent of all processes"
1164//usage:
1165//usage:#define init_notes_usage
1166//usage: "This version of init is designed to be run only by the kernel.\n"
1167//usage: "\n"
1168//usage: "BusyBox init doesn't support multiple runlevels. The runlevels field of\n"
1169//usage: "the /etc/inittab file is completely ignored by BusyBox init. If you want\n"
1170//usage: "runlevels, use sysvinit.\n"
1171//usage: "\n"
1172//usage: "BusyBox init works just fine without an inittab. If no inittab is found,\n"
1173//usage: "it has the following default behavior:\n"
1174//usage: "\n"
1175//usage: " ::sysinit:/etc/init.d/rcS\n"
1176//usage: " ::askfirst:/bin/sh\n"
1177//usage: " ::ctrlaltdel:/sbin/reboot\n"
1178//usage: " ::shutdown:/sbin/swapoff -a\n"
1179//usage: " ::shutdown:/bin/umount -a -r\n"
1180//usage: " ::restart:/sbin/init\n"
1181//usage: "\n"
1182//usage: "if it detects that /dev/console is _not_ a serial console, it will also run:\n"
1183//usage: "\n"
1184//usage: " tty2::askfirst:/bin/sh\n"
1185//usage: " tty3::askfirst:/bin/sh\n"
1186//usage: " tty4::askfirst:/bin/sh\n"
1187//usage: "\n"
1188//usage: "If you choose to use an /etc/inittab file, the inittab entry format is as follows:\n"
1189//usage: "\n"
1190//usage: " <id>:<runlevels>:<action>:<process>\n"
1191//usage: "\n"
1192//usage: " <id>:\n"
1193//usage: "\n"
1194//usage: " WARNING: This field has a non-traditional meaning for BusyBox init!\n"
1195//usage: " The id field is used by BusyBox init to specify the controlling tty for\n"
1196//usage: " the specified process to run on. The contents of this field are\n"
1197//usage: " appended to \"/dev/\" and used as-is. There is no need for this field to\n"
1198//usage: " be unique, although if it isn't you may have strange results. If this\n"
1199//usage: " field is left blank, the controlling tty is set to the console. Also\n"
1200//usage: " note that if BusyBox detects that a serial console is in use, then only\n"
1201//usage: " entries whose controlling tty is either the serial console or /dev/null\n"
1202//usage: " will be run. BusyBox init does nothing with utmp. We don't need no\n"
1203//usage: " stinkin' utmp.\n"
1204//usage: "\n"
1205//usage: " <runlevels>:\n"
1206//usage: "\n"
1207//usage: " The runlevels field is completely ignored.\n"
1208//usage: "\n"
1209//usage: " <action>:\n"
1210//usage: "\n"
1211//usage: " Valid actions include: sysinit, respawn, askfirst, wait,\n"
1212//usage: " once, restart, ctrlaltdel, and shutdown.\n"
1213//usage: "\n"
1214//usage: " The available actions can be classified into two groups: actions\n"
1215//usage: " that are run only once, and actions that are re-run when the specified\n"
1216//usage: " process exits.\n"
1217//usage: "\n"
1218//usage: " Run only-once actions:\n"
1219//usage: "\n"
1220//usage: " 'sysinit' is the first item run on boot. init waits until all\n"
1221//usage: " sysinit actions are completed before continuing. Following the\n"
1222//usage: " completion of all sysinit actions, all 'wait' actions are run.\n"
1223//usage: " 'wait' actions, like 'sysinit' actions, cause init to wait until\n"
1224//usage: " the specified task completes. 'once' actions are asynchronous,\n"
1225//usage: " therefore, init does not wait for them to complete. 'restart' is\n"
1226//usage: " the action taken to restart the init process. By default this should\n"
1227//usage: " simply run /sbin/init, but can be a script which runs pivot_root or it\n"
1228//usage: " can do all sorts of other interesting things. The 'ctrlaltdel' init\n"
1229//usage: " actions are run when the system detects that someone on the system\n"
1230//usage: " console has pressed the CTRL-ALT-DEL key combination. Typically one\n"
1231//usage: " wants to run 'reboot' at this point to cause the system to reboot.\n"
1232//usage: " Finally the 'shutdown' action specifies the actions to taken when\n"
1233//usage: " init is told to reboot. Unmounting filesystems and disabling swap\n"
1234//usage: " is a very good here.\n"
1235//usage: "\n"
1236//usage: " Run repeatedly actions:\n"
1237//usage: "\n"
1238//usage: " 'respawn' actions are run after the 'once' actions. When a process\n"
1239//usage: " started with a 'respawn' action exits, init automatically restarts\n"
1240//usage: " it. Unlike sysvinit, BusyBox init does not stop processes from\n"
1241//usage: " respawning out of control. The 'askfirst' actions acts just like\n"
1242//usage: " respawn, except that before running the specified process it\n"
1243//usage: " displays the line \"Please press Enter to activate this console.\"\n"
1244//usage: " and then waits for the user to press enter before starting the\n"
1245//usage: " specified process.\n"
1246//usage: "\n"
1247//usage: " Unrecognized actions (like initdefault) will cause init to emit an\n"
1248//usage: " error message, and then go along with its business. All actions are\n"
1249//usage: " run in the order they appear in /etc/inittab.\n"
1250//usage: "\n"
1251//usage: " <process>:\n"
1252//usage: "\n"
1253//usage: " Specifies the process to be executed and its command line.\n"
1254//usage: "\n"
1255//usage: "Example /etc/inittab file:\n"
1256//usage: "\n"
1257//usage: " # This is run first except when booting in single-user mode\n"
1258//usage: " #\n"
1259//usage: " ::sysinit:/etc/init.d/rcS\n"
1260//usage: " \n"
1261//usage: " # /bin/sh invocations on selected ttys\n"
1262//usage: " #\n"
1263//usage: " # Start an \"askfirst\" shell on the console (whatever that may be)\n"
1264//usage: " ::askfirst:-/bin/sh\n"
1265//usage: " # Start an \"askfirst\" shell on /dev/tty2-4\n"
1266//usage: " tty2::askfirst:-/bin/sh\n"
1267//usage: " tty3::askfirst:-/bin/sh\n"
1268//usage: " tty4::askfirst:-/bin/sh\n"
1269//usage: " \n"
1270//usage: " # /sbin/getty invocations for selected ttys\n"
1271//usage: " #\n"
1272//usage: " tty4::respawn:/sbin/getty 38400 tty4\n"
1273//usage: " tty5::respawn:/sbin/getty 38400 tty5\n"
1274//usage: " \n"
1275//usage: " \n"
1276//usage: " # Example of how to put a getty on a serial line (for a terminal)\n"
1277//usage: " #\n"
1278//usage: " #::respawn:/sbin/getty -L ttyS0 9600 vt100\n"
1279//usage: " #::respawn:/sbin/getty -L ttyS1 9600 vt100\n"
1280//usage: " #\n"
1281//usage: " # Example how to put a getty on a modem line\n"
1282//usage: " #::respawn:/sbin/getty 57600 ttyS2\n"
1283//usage: " \n"
1284//usage: " # Stuff to do when restarting the init process\n"
1285//usage: " ::restart:/sbin/init\n"
1286//usage: " \n"
1287//usage: " # Stuff to do before rebooting\n"
1288//usage: " ::ctrlaltdel:/sbin/reboot\n"
1289//usage: " ::shutdown:/bin/umount -a -r\n"
1290//usage: " ::shutdown:/sbin/swapoff -a\n"