blob: 89bbafd13fc38de0bbb91cbb5f19a485e007d206 [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 *
Rob Landley2edf5262006-01-22 02:41:51 +00009 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
Eric Andersenc4996011999-10-20 22:08:37 +000010 */
11
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000012#include "libbb.h"
Bernhard Reutner-Fischerf4701962008-01-27 12:50:12 +000013#include <syslog.h>
Eric Andersenb186d981999-12-03 09:19:54 +000014#include <paths.h>
Eric Andersen85e5e722003-07-22 08:56:55 +000015#include <sys/reboot.h>
Denis Vlasenko6c622462009-01-29 02:01:04 +000016#include <sys/resource.h>
Denis Vlasenko5981ba52009-03-19 02:35:44 +000017#include <linux/vt.h>
Eric Andersen2c1de612003-04-24 11:41:28 +000018
Denis Vlasenko72c99af2009-01-31 01:03:45 +000019
Denis Vlasenko5cb54b52008-10-21 17:14:26 +000020/* Was a CONFIG_xxx option. A lot of people were building
21 * not fully functional init by switching it on! */
22#define DEBUG_INIT 0
23
Denis Vlasenko6c622462009-01-29 02:01:04 +000024#define COMMAND_SIZE 256
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +000025#define CONSOLE_NAME_SIZE 32
Eric Andersenbd22ed82000-07-08 18:55:24 +000026
Denis Vlasenko72c99af2009-01-31 01:03:45 +000027/* Default sysinit script. */
Erik Andersen96e2abd2000-01-07 11:40:44 +000028#ifndef INIT_SCRIPT
Denis Vlasenko72c99af2009-01-31 01:03:45 +000029#define INIT_SCRIPT "/etc/init.d/rcS"
Erik Andersen96e2abd2000-01-07 11:40:44 +000030#endif
Erik Andersen9c88cac1999-12-30 09:25:17 +000031
Denis Vlasenko72c99af2009-01-31 01:03:45 +000032/* Each type of actions can appear many times. They will be
33 * handled in order. RESTART is an exception, only 1st is used.
34 */
35/* Start these actions first and wait for completion */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000036#define SYSINIT 0x01
Denis Vlasenko72c99af2009-01-31 01:03:45 +000037/* Start these after SYSINIT and wait for completion */
38#define WAIT 0x02
39/* Start these after WAIT and *dont* wait for completion */
40#define ONCE 0x04
41/*
42 * NB: while SYSINIT/WAIT/ONCE are being processed,
Denys Vlasenko6e542492009-11-15 03:07:19 +010043 * SIGHUP ("reread /etc/inittab") will be processed only after
44 * each group of actions. If new inittab adds, say, a SYSINIT action,
45 * it will not be run, since init is already "past SYSINIT stage".
Denis Vlasenko72c99af2009-01-31 01:03:45 +000046 */
47/* Start these after ONCE are started, restart on exit */
48#define RESPAWN 0x08
49/* Like RESPAWN, but wait for <Enter> to be pressed on tty */
50#define ASKFIRST 0x10
51/*
52 * Start these on SIGINT, and wait for completion.
53 * Then go back to respawning RESPAWN and ASKFIRST actions.
54 * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
55 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000056#define CTRLALTDEL 0x20
Denis Vlasenko72c99af2009-01-31 01:03:45 +000057/*
58 * Start these before killing all processes in preparation for
59 * running RESTART actions or doing low-level halt/reboot/poweroff
60 * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
61 * Wait for completion before proceeding.
62 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000063#define SHUTDOWN 0x40
Denis Vlasenko72c99af2009-01-31 01:03:45 +000064/*
65 * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
66 * then all processes are killed, then init exec's 1st RESTART action,
67 * replacing itself by it. If no RESTART action specified,
68 * SIGQUIT has no effect.
69 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000070#define RESTART 0x80
Erik Andersen7dc16072000-01-04 01:10:25 +000071
Denis Vlasenko72c99af2009-01-31 01:03:45 +000072
73/* A linked list of init_actions, to be read from inittab */
Eric Andersen0298be82002-03-05 15:12:19 +000074struct init_action {
Eric Andersen0298be82002-03-05 15:12:19 +000075 struct init_action *next;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +000076 pid_t pid;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +000077 uint8_t action_type;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +000078 char terminal[CONSOLE_NAME_SIZE];
Denis Vlasenkoa37e7132008-02-19 02:57:07 +000079 char command[COMMAND_SIZE];
Erik Andersen7dc16072000-01-04 01:10:25 +000080};
Erik Andersen7dc16072000-01-04 01:10:25 +000081
Eric Andersen0298be82002-03-05 15:12:19 +000082static struct init_action *init_action_list = NULL;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +000083
Denis Vlasenko4c978632007-02-03 03:31:13 +000084static const char *log_console = VC_5;
Rob Landleybc68cd12006-03-10 19:22:06 +000085
86enum {
Denis Vlasenkoec27feb2007-02-17 15:52:02 +000087 L_LOG = 0x1,
88 L_CONSOLE = 0x2,
Rob Landleybc68cd12006-03-10 19:22:06 +000089#ifndef RB_HALT_SYSTEM
Bernhard Reutner-Fischercf1f2ac2006-06-02 10:43:17 +000090 RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
Rob Landleybc68cd12006-03-10 19:22:06 +000091 RB_ENABLE_CAD = 0x89abcdef,
92 RB_DISABLE_CAD = 0,
93 RB_POWER_OFF = 0x4321fedc,
94 RB_AUTOBOOT = 0x01234567,
Eric Andersen0298be82002-03-05 15:12:19 +000095#endif
Rob Landleybc68cd12006-03-10 19:22:06 +000096};
Erik Andersen42094cd2000-03-20 21:34:52 +000097
Erik Andersen42094cd2000-03-20 21:34:52 +000098/* Print a message to the specified device.
Denis Vlasenko671ca332008-02-19 14:13:20 +000099 * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
100 * NB: careful, we can be called after vfork!
101 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000102#define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
Denis Vlasenko671ca332008-02-19 14:13:20 +0000103static void message(int where, const char *fmt, ...)
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000104 __attribute__ ((format(printf, 2, 3)));
Denis Vlasenko671ca332008-02-19 14:13:20 +0000105static void message(int where, const char *fmt, ...)
Eric Andersen0460ff21999-10-25 23:32:44 +0000106{
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000107 va_list arguments;
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000108 unsigned l;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000109 char msg[128];
110
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000111 msg[0] = '\r';
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000112 va_start(arguments, fmt);
Denis Vlasenko1bcdcd22008-12-09 21:23:31 +0000113 l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
114 if (l > sizeof(msg) - 1)
115 l = sizeof(msg) - 1;
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000116 va_end(arguments);
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000117
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000118#if ENABLE_FEATURE_INIT_SYSLOG
119 msg[l] = '\0';
120 if (where & L_LOG) {
121 /* Log the message to syslogd */
122 openlog("init", 0, LOG_DAEMON);
123 /* don't print "\r" */
124 syslog(LOG_INFO, "%s", msg + 1);
125 closelog();
126 }
127 msg[l++] = '\n';
128 msg[l] = '\0';
129#else
130 {
131 static int log_fd = -1;
132
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000133 msg[l++] = '\n';
134 msg[l] = '\0';
135 /* Take full control of the log tty, and never close it.
136 * It's mine, all mine! Muhahahaha! */
137 if (log_fd < 0) {
138 if (!log_console) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000139 log_fd = STDERR_FILENO;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000140 } else {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000141 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
142 if (log_fd < 0) {
143 bb_error_msg("can't log to %s", log_console);
Denis Vlasenko671ca332008-02-19 14:13:20 +0000144 where = L_CONSOLE;
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000145 } else {
146 close_on_exec_on(log_fd);
147 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000148 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000149 }
Denis Vlasenko671ca332008-02-19 14:13:20 +0000150 if (where & L_LOG) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000151 full_write(log_fd, msg, l);
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000152 if (log_fd == STDERR_FILENO)
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000153 return; /* don't print dup messages */
154 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000155 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000156#endif
Eric Andersen4c781471999-11-26 08:12:56 +0000157
Denis Vlasenko671ca332008-02-19 14:13:20 +0000158 if (where & L_CONSOLE) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000159 /* Send console messages to console so people will see them. */
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000160 full_write(STDERR_FILENO, msg, l);
Eric Andersen3ae0c781999-11-04 01:13:21 +0000161 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000162}
163
Eric Andersen74400cc2001-10-18 04:11:39 +0000164static void console_init(void)
Eric Andersen0460ff21999-10-25 23:32:44 +0000165{
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000166 int vtno;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000167 char *s;
Eric Andersen0460ff21999-10-25 23:32:44 +0000168
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000169 s = getenv("CONSOLE");
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000170 if (!s)
171 s = getenv("console");
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000172 if (s) {
173 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
174 if (fd >= 0) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000175 dup2(fd, STDIN_FILENO);
176 dup2(fd, STDOUT_FILENO);
177 xmove_fd(fd, STDERR_FILENO);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000178 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000179 dbg_message(L_LOG, "console='%s'", s);
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000180 } else {
Denis Vlasenkofb274df2008-03-17 13:26:51 +0000181 /* Make sure fd 0,1,2 are not closed
182 * (so that they won't be used by future opens) */
Denis Vlasenkod48e81f2008-07-06 07:00:11 +0000183 bb_sanitize_stdio();
Denis Vlasenkoa34b8a42008-11-29 23:14:37 +0000184// Users report problems
185// /* Make sure init can't be blocked by writing to stderr */
186// fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
Eric Andersen07e52971999-11-07 07:38:08 +0000187 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000188
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000189 s = getenv("TERM");
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000190 if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) {
191 /* Not a linux terminal, probably serial console.
192 * Force the TERM setting to vt102
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000193 * if TERM is set to linux (the default) */
194 if (!s || strcmp(s, "linux") == 0)
195 putenv((char*)"TERM=vt102");
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000196 if (!ENABLE_FEATURE_INIT_SYSLOG)
197 log_console = NULL;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000198 } else if (!s)
199 putenv((char*)"TERM=linux");
Eric Andersen0460ff21999-10-25 23:32:44 +0000200}
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000201
Denis Vlasenko671ca332008-02-19 14:13:20 +0000202/* Set terminal settings to reasonable defaults.
203 * NB: careful, we can be called after vfork! */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000204static void set_sane_term(void)
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000205{
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000206 struct termios tty;
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000207
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000208 tcgetattr(STDIN_FILENO, &tty);
209
210 /* set control chars */
211 tty.c_cc[VINTR] = 3; /* C-c */
212 tty.c_cc[VQUIT] = 28; /* C-\ */
213 tty.c_cc[VERASE] = 127; /* C-? */
214 tty.c_cc[VKILL] = 21; /* C-u */
215 tty.c_cc[VEOF] = 4; /* C-d */
216 tty.c_cc[VSTART] = 17; /* C-q */
217 tty.c_cc[VSTOP] = 19; /* C-s */
218 tty.c_cc[VSUSP] = 26; /* C-z */
219
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000220 /* use line discipline 0 */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000221 tty.c_line = 0;
222
223 /* Make it be sane */
224 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
225 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
226
227 /* input modes */
228 tty.c_iflag = ICRNL | IXON | IXOFF;
229
230 /* output modes */
231 tty.c_oflag = OPOST | ONLCR;
232
233 /* local modes */
234 tty.c_lflag =
235 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
236
Denis Vlasenko202ac502008-11-05 13:20:58 +0000237 tcsetattr_stdin_TCSANOW(&tty);
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000238}
239
Denis Vlasenko671ca332008-02-19 14:13:20 +0000240/* Open the new terminal device.
241 * NB: careful, we can be called after vfork! */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000242static int open_stdio_to_tty(const char* tty_name)
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000243{
244 /* empty tty_name means "use init's tty", else... */
245 if (tty_name[0]) {
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000246 int fd;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000247
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000248 close(STDIN_FILENO);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000249 /* fd can be only < 0 or 0: */
250 fd = device_open(tty_name, O_RDWR);
251 if (fd) {
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000252 message(L_LOG | L_CONSOLE, "can't open %s: %s",
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000253 tty_name, strerror(errno));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000254 return 0; /* failure */
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000255 }
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000256 dup2(STDIN_FILENO, STDOUT_FILENO);
257 dup2(STDIN_FILENO, STDERR_FILENO);
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000258 }
Denis Vlasenkod238a472007-03-05 19:22:04 +0000259 set_sane_term();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000260 return 1; /* success */
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000261}
262
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100263static void reset_sighandlers_and_unblock_sigs(void)
264{
265 bb_signals(0
266 + (1 << SIGUSR1)
267 + (1 << SIGUSR2)
268 + (1 << SIGTERM)
269 + (1 << SIGQUIT)
270 + (1 << SIGINT)
271 + (1 << SIGHUP)
272 + (1 << SIGTSTP)
273 , SIG_DFL);
274 sigprocmask_allsigs(SIG_UNBLOCK);
275}
276
Denis Vlasenko671ca332008-02-19 14:13:20 +0000277/* Wrapper around exec:
278 * Takes string (max COMMAND_SIZE chars).
279 * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
280 * Otherwise splits words on whitespace, deals with leading dash,
281 * and uses plain exec().
282 * NB: careful, we can be called after vfork!
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000283 */
284static void init_exec(const char *command)
285{
286 char *cmd[COMMAND_SIZE / 2];
287 char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000288 int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000289
290 /* See if any special /bin/sh requiring characters are present */
291 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
292 strcpy(buf, "exec ");
293 strcpy(buf + 5, command + dash); /* excluding "-" */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000294 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000295 cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
296 cmd[1] = (char*)"-c";
297 cmd[2] = buf;
298 cmd[3] = NULL;
299 } else {
300 /* Convert command (char*) into cmd (char**, one word per string) */
301 char *word, *next;
302 int i = 0;
303 next = strcpy(buf, command); /* including "-" */
304 while ((word = strsep(&next, " \t")) != NULL) {
305 if (*word != '\0') { /* not two spaces/tabs together? */
306 cmd[i] = word;
307 i++;
308 }
309 }
310 cmd[i] = NULL;
311 }
312 /* If we saw leading "-", it is interactive shell.
313 * Try harder to give it a controlling tty.
314 * And skip "-" in actual exec call. */
315 if (dash) {
316 /* _Attempt_ to make stdin a controlling tty. */
317 if (ENABLE_FEATURE_INIT_SCTTY)
318 ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
319 }
320 BB_EXECVP(cmd[0] + dash, cmd);
Denys Vlasenko6331cf02009-11-13 09:08:27 +0100321 message(L_LOG | L_CONSOLE, "can't run '%s': %s", cmd[0], strerror(errno));
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000322 /* returns if execvp fails */
323}
324
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000325/* Used only by run_actions */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000326static pid_t run(const struct init_action *a)
Eric Andersen0298be82002-03-05 15:12:19 +0000327{
Mike Frysinger10427ab2005-07-06 05:00:48 +0000328 pid_t pid;
Erik Andersenac6e71f2000-01-08 22:04:33 +0000329
Denis Vlasenko47741792009-03-10 16:01:57 +0000330 /* Careful: don't be affected by a signal in vforked child */
331 sigprocmask_allsigs(SIG_BLOCK);
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000332 if (BB_MMU && (a->action_type & ASKFIRST))
333 pid = fork();
334 else
335 pid = vfork();
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000336 if (pid < 0)
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000337 message(L_LOG | L_CONSOLE, "can't fork");
Denis Vlasenko47741792009-03-10 16:01:57 +0000338 if (pid) {
339 sigprocmask_allsigs(SIG_UNBLOCK);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000340 return pid; /* Parent or error */
Denis Vlasenko47741792009-03-10 16:01:57 +0000341 }
Eric Andersen0298be82002-03-05 15:12:19 +0000342
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000343 /* Child */
344
Denis Vlasenko966bb432007-02-27 19:20:33 +0000345 /* Reset signal handlers that were set by the parent process */
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100346 reset_sighandlers_and_unblock_sigs();
Eric Andersen2f6c04f1999-11-01 23:59:44 +0000347
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000348 /* Create a new session and make ourself the process group leader */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000349 setsid();
Eric Andersen599e3ce2002-07-03 11:08:10 +0000350
Denis Vlasenko966bb432007-02-27 19:20:33 +0000351 /* Open the new terminal device */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000352 if (!open_stdio_to_tty(a->terminal))
353 _exit(EXIT_FAILURE);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000354
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000355 /* NB: on NOMMU we can't wait for input in child, so
356 * "askfirst" will work the same as "respawn". */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000357 if (BB_MMU && (a->action_type & ASKFIRST)) {
Denis Vlasenko6ca409e2007-08-12 20:58:27 +0000358 static const char press_enter[] ALIGN1 =
Denis Vlasenko966bb432007-02-27 19:20:33 +0000359#ifdef CUSTOMIZED_BANNER
360#include CUSTOMIZED_BANNER
Eric Andersen1f50e842004-08-16 09:29:42 +0000361#endif
Denis Vlasenko966bb432007-02-27 19:20:33 +0000362 "\nPlease press Enter to activate this console. ";
363 char c;
364 /*
365 * Save memory by not exec-ing anything large (like a shell)
366 * before the user wants it. This is critical if swap is not
367 * enabled and the system has low memory. Generally this will
368 * be run on the second virtual console, and the first will
369 * be allowed to start a shell or whatever an init script
370 * specifies.
371 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000372 dbg_message(L_LOG, "waiting for enter to start '%s'"
Denis Vlasenko966bb432007-02-27 19:20:33 +0000373 "(pid %d, tty '%s')\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000374 a->command, getpid(), a->terminal);
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000375 full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
376 while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000377 continue;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000378 }
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000379
Denis Vlasenko6c622462009-01-29 02:01:04 +0000380 /*
381 * When a file named /.init_enable_core exists, setrlimit is called
382 * before processes are spawned to set core file size as unlimited.
383 * This is for debugging only. Don't use this is production, unless
384 * you want core dumps lying about....
385 */
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000386 if (ENABLE_FEATURE_INIT_COREDUMPS) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000387 if (access("/.init_enable_core", F_OK) == 0) {
Denis Vlasenko966bb432007-02-27 19:20:33 +0000388 struct rlimit limit;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000389 limit.rlim_cur = RLIM_INFINITY;
390 limit.rlim_max = RLIM_INFINITY;
391 setrlimit(RLIMIT_CORE, &limit);
Erik Andersen983b51b2000-04-04 18:14:25 +0000392 }
Erik Andersen05df2392000-01-13 04:43:48 +0000393 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000394
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000395 /* Log the process name and args */
396 message(L_LOG, "starting pid %d, tty '%s': '%s'",
397 getpid(), a->terminal, a->command);
398
Denis Vlasenko966bb432007-02-27 19:20:33 +0000399 /* Now run it. The new program will take over this PID,
400 * so nothing further in init.c should be run. */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000401 init_exec(a->command);
Denis Vlasenko966bb432007-02-27 19:20:33 +0000402 /* We're still here? Some error happened. */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000403 _exit(-1);
Eric Andersen0460ff21999-10-25 23:32:44 +0000404}
405
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000406static struct init_action *mark_terminated(pid_t pid)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000407{
408 struct init_action *a;
409
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000410 if (pid > 0) {
411 for (a = init_action_list; a; a = a->next) {
412 if (a->pid == pid) {
413 a->pid = 0;
414 return a;
415 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000416 }
417 }
418 return NULL;
419}
420
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000421static void waitfor(pid_t pid)
422{
423 /* waitfor(run(x)): protect against failed fork inside run() */
424 if (pid <= 0)
425 return;
426
427 /* Wait for any child (prevent zombies from exiting orphaned processes)
428 * but exit the loop only when specified one has exited. */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000429 while (1) {
430 pid_t wpid = wait(NULL);
431 mark_terminated(wpid);
432 /* Unsafe. SIGTSTP handler might have wait'ed it already */
433 /*if (wpid == pid) break;*/
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000434 /* More reliable: */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000435 if (kill(pid, 0))
436 break;
437 }
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000438}
439
Eric Andersen0298be82002-03-05 15:12:19 +0000440/* Run all commands of a particular type */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000441static void run_actions(int action_type)
Eric Andersen219d6f51999-11-02 19:43:01 +0000442{
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000443 struct init_action *a;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000444
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000445 for (a = init_action_list; a; a = a->next) {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000446 if (!(a->action_type & action_type))
447 continue;
Eric Andersen5222d312002-07-03 05:15:23 +0000448
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000449 if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
450 pid_t pid = run(a);
451 if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
452 waitfor(pid);
453 }
454 if (a->action_type & (RESPAWN | ASKFIRST)) {
455 /* Only run stuff with pid == 0. If pid != 0,
456 * it is already running
457 */
458 if (a->pid == 0)
459 a->pid = run(a);
Eric Andersen730f8262001-12-17 23:13:08 +0000460 }
461 }
462}
463
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000464static void new_init_action(uint8_t action_type, const char *command, const char *cons)
Erik Andersen7dc16072000-01-04 01:10:25 +0000465{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000466 struct init_action *a, **nextp;
Erik Andersen9e737252000-01-06 01:16:13 +0000467
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000468 /* Scenario:
469 * old inittab:
470 * ::shutdown:umount -a -r
471 * ::shutdown:swapoff -a
472 * new inittab:
473 * ::shutdown:swapoff -a
474 * ::shutdown:umount -a -r
475 * On reload, we must ensure entries end up in correct order.
476 * To achieve that, if we find a matching entry, we move it
477 * to the end.
478 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000479 nextp = &init_action_list;
480 while ((a = *nextp) != NULL) {
481 /* Don't enter action if it's already in the list,
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000482 * This prevents losing running RESPAWNs.
483 */
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000484 if ((strcmp(a->command, command) == 0)
Denis Vlasenkob74a2db2008-07-21 21:34:51 +0000485 && (strcmp(a->terminal, cons) == 0)
486 ) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000487 /* Remove from list */
488 *nextp = a->next;
489 /* Find the end of the list */
490 while (*nextp != NULL)
491 nextp = &(*nextp)->next;
492 a->next = NULL;
493 break;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000494 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000495 nextp = &a->next;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000496 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000497
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000498 if (!a)
499 a = xzalloc(sizeof(*a));
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000500 /* Append to the end of the list */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000501 *nextp = a;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000502 a->action_type = action_type;
503 safe_strncpy(a->command, command, sizeof(a->command));
504 safe_strncpy(a->terminal, cons, sizeof(a->terminal));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000505 dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000506 a->command, a->action_type, a->terminal);
Erik Andersen7dc16072000-01-04 01:10:25 +0000507}
508
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000509/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersen9e737252000-01-06 01:16:13 +0000510 * then parse_inittab() simply adds in some default
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000511 * actions(i.e., runs INIT_SCRIPT and then starts a pair
512 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
513 * _is_ defined, but /etc/inittab is missing, this
Erik Andersen812d4662000-01-07 18:30:40 +0000514 * results in the same set of default behaviors.
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000515 */
Eric Andersen3e6ff902001-03-09 21:24:12 +0000516static void parse_inittab(void)
Erik Andersen7dc16072000-01-04 01:10:25 +0000517{
Denis Vlasenko6c622462009-01-29 02:01:04 +0000518#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000519 char *token[4];
Denis Vlasenko6c622462009-01-29 02:01:04 +0000520 parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000521
Denis Vlasenko6c622462009-01-29 02:01:04 +0000522 if (parser == NULL)
523#endif
524 {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000525 /* No inittab file - set up some default behavior */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000526 /* Reboot on Ctrl-Alt-Del */
527 new_init_action(CTRLALTDEL, "reboot", "");
528 /* Umount all filesystems on halt/reboot */
529 new_init_action(SHUTDOWN, "umount -a -r", "");
530 /* Swapoff on halt/reboot */
531 if (ENABLE_SWAPONOFF)
532 new_init_action(SHUTDOWN, "swapoff -a", "");
533 /* Prepare to restart init when a QUIT is received */
534 new_init_action(RESTART, "init", "");
535 /* Askfirst shell on tty1-4 */
536 new_init_action(ASKFIRST, bb_default_login_shell, "");
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000537//TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000538 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
539 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
540 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
541 /* sysinit */
542 new_init_action(SYSINIT, INIT_SCRIPT, "");
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000543 return;
544 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000545
546#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000547 /* optional_tty:ignored_runlevel:action:command
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000548 * Delims are not to be collapsed and need exactly 4 tokens
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000549 */
Denis Vlasenko084266e2008-07-26 23:08:31 +0000550 while (config_read(parser, token, 4, 0, "#:",
551 PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000552 /* order must correspond to SYSINIT..RESTART constants */
553 static const char actions[] ALIGN1 =
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000554 "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
Denis Vlasenko6c622462009-01-29 02:01:04 +0000555 "ctrlaltdel\0""shutdown\0""restart\0";
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000556 int action;
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000557 char *tty = token[0];
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000558
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000559 if (!token[3]) /* less than 4 tokens */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000560 goto bad_entry;
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000561 action = index_in_strings(actions, token[2]);
562 if (action < 0 || !token[3][0]) /* token[3]: command */
563 goto bad_entry;
564 /* turn .*TTY -> /dev/TTY */
565 if (tty[0]) {
566 if (strncmp(tty, "/dev/", 5) == 0)
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000567 tty += 5;
568 tty = concat_path_file("/dev/", tty);
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000569 }
570 new_init_action(1 << action, token[3], tty);
571 if (tty[0])
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000572 free(tty);
573 continue;
574 bad_entry:
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000575 message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
576 parser->lineno);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000577 }
578 config_close(parser);
Denis Vlasenko6c622462009-01-29 02:01:04 +0000579#endif
Erik Andersen7dc16072000-01-04 01:10:25 +0000580}
581
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000582static void pause_and_low_level_reboot(unsigned magic) NORETURN;
583static void pause_and_low_level_reboot(unsigned magic)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000584{
585 pid_t pid;
586
587 /* Allow time for last message to reach serial console, etc */
588 sleep(1);
589
590 /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
591 * in linux/kernel/sys.c, which can cause the machine to panic when
592 * the init process exits... */
593 pid = vfork();
594 if (pid == 0) { /* child */
595 reboot(magic);
596 _exit(EXIT_SUCCESS);
597 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000598 while (1)
599 sleep(1);
600}
601
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000602static void run_shutdown_and_kill_processes(void)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000603{
604 /* Run everything to be run at "shutdown". This is done _prior_
605 * to killing everything, in case people wish to use scripts to
606 * shut things down gracefully... */
607 run_actions(SHUTDOWN);
608
609 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
610
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000611 /* Send signals to every process _except_ pid 1 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000612 kill(-1, SIGTERM);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000613 message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000614 sync();
615 sleep(1);
616
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000617 kill(-1, SIGKILL);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000618 message(L_CONSOLE, "Sent SIG%s to all processes", "KILL");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000619 sync();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000620 /*sleep(1); - callers take care about making a pause */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000621}
622
623/* Signal handling by init:
624 *
625 * For process with PID==1, on entry kernel sets all signals to SIG_DFL
626 * and unmasks all signals. However, for process with PID==1,
627 * default action (SIG_DFL) on any signal is to ignore it,
628 * even for special signals SIGKILL and SIGCONT.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000629 * Also, any signal can be caught or blocked.
Denis Vlasenkofc2a4fc2009-01-31 01:07:05 +0000630 * (but SIGSTOP is still handled specially, at least in 2.6.20)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000631 *
632 * We install two kinds of handlers, "immediate" and "delayed".
633 *
634 * Immediate handlers execute at any time, even while, say, sysinit
635 * is running.
636 *
637 * Delayed handlers just set a flag variable. The variable is checked
638 * in the main loop and acted upon.
639 *
640 * halt/poweroff/reboot and restart have immediate handlers.
641 * They only traverse linked list of struct action's, never modify it,
642 * this should be safe to do even in signal handler. Also they
643 * never return.
644 *
645 * SIGSTOP and SIGTSTP have immediate handlers. They just wait
646 * for SIGCONT to happen.
647 *
648 * SIGHUP has a delayed handler, because modifying linked list
649 * of struct action's from a signal handler while it is manipulated
650 * by the program may be disastrous.
651 *
652 * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
653 * it to happen even somewhere inside "sysinit" would be a bit awkward.
654 *
655 * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
Denis Vlasenko93b38202009-02-14 20:58:13 +0000656 * and only one will be remembered and acted upon.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000657 */
658
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100659/* The SIGUSR[12]/SIGTERM handler */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000660static void halt_reboot_pwoff(int sig) NORETURN;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000661static void halt_reboot_pwoff(int sig)
662{
663 const char *m;
664 unsigned rb;
665
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100666 /* We may call run() and it unmasks signals,
667 * including the one masked inside this signal handler.
668 * Testcase which would start multiple reboot scripts:
669 * while true; do reboot; done
670 * Preventing it:
671 */
672 reset_sighandlers_and_unblock_sigs();
673
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000674 run_shutdown_and_kill_processes();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000675
676 m = "halt";
677 rb = RB_HALT_SYSTEM;
678 if (sig == SIGTERM) {
679 m = "reboot";
680 rb = RB_AUTOBOOT;
681 } else if (sig == SIGUSR2) {
682 m = "poweroff";
683 rb = RB_POWER_OFF;
684 }
685 message(L_CONSOLE, "Requesting system %s", m);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000686 pause_and_low_level_reboot(rb);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000687 /* not reached */
688}
689
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100690/* Handler for QUIT - exec "restart" action,
691 * else (no such action defined) do nothing */
692static void restart_handler(int sig UNUSED_PARAM)
693{
694 struct init_action *a;
695
696 for (a = init_action_list; a; a = a->next) {
697 if (!(a->action_type & RESTART))
698 continue;
699
700 /* Starting from here, we won't return.
701 * Thus don't need to worry about preserving errno
702 * and such.
703 */
704
705 reset_sighandlers_and_unblock_sigs();
706
707 run_shutdown_and_kill_processes();
708
709 /* Allow Ctrl-Alt-Del to reboot the system.
710 * This is how kernel sets it up for init, we follow suit.
711 */
712 reboot(RB_ENABLE_CAD); /* misnomer */
713
714 if (open_stdio_to_tty(a->terminal)) {
715 dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
716 /* Theoretically should be safe.
717 * But in practice, kernel bugs may leave
718 * unkillable processes, and wait() may block forever.
719 * Oh well. Hoping "new" init won't be too surprised
720 * by having children it didn't create.
721 */
722 //while (wait(NULL) > 0)
723 // continue;
724 init_exec(a->command);
725 }
726 /* Open or exec failed */
727 pause_and_low_level_reboot(RB_HALT_SYSTEM);
728 /* not reached */
729 }
730}
731
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000732/* The SIGSTOP/SIGTSTP handler
733 * NB: inside it, all signals except SIGCONT are masked
734 * via appropriate setup in sigaction().
735 */
736static void stop_handler(int sig UNUSED_PARAM)
737{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000738 smallint saved_bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000739 int saved_errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000740
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000741 saved_bb_got_signal = bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000742 saved_errno = errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000743 signal(SIGCONT, record_signo);
744
745 while (1) {
746 pid_t wpid;
747
748 if (bb_got_signal == SIGCONT)
749 break;
750 /* NB: this can accidentally wait() for a process
751 * which we waitfor() elsewhere! waitfor() must have
752 * code which is resilient against this.
753 */
754 wpid = wait_any_nohang(NULL);
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000755 mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000756 sleep(1);
757 }
758
759 signal(SIGCONT, SIG_DFL);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000760 errno = saved_errno;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000761 bb_got_signal = saved_bb_got_signal;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000762}
763
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000764#if ENABLE_FEATURE_USE_INITTAB
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000765static void reload_inittab(void)
Eric Andersen6fd0e312003-07-22 09:48:56 +0000766{
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000767 struct init_action *a, **nextp;
Eric Andersen82baf632004-10-08 08:21:54 +0000768
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000769 message(L_LOG, "reloading /etc/inittab");
Eric Andersen82baf632004-10-08 08:21:54 +0000770
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000771 /* Disable old entries */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000772 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100773 a->action_type = 0;
Eric Andersen82baf632004-10-08 08:21:54 +0000774
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000775 /* Append new entries, or modify existing entries
Denys Vlasenko6e542492009-11-15 03:07:19 +0100776 * (incl. setting a->action_type) if cmd and device name
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000777 * match new ones. End result: only entries with
Denys Vlasenko6e542492009-11-15 03:07:19 +0100778 * a->action_type == 0 are stale.
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000779 */
Eric Andersen82baf632004-10-08 08:21:54 +0000780 parse_inittab();
781
Denis Vlasenko93b38202009-02-14 20:58:13 +0000782#if ENABLE_FEATURE_KILL_REMOVED
783 /* Kill stale entries */
784 /* Be nice and send SIGTERM first */
785 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100786 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000787 kill(a->pid, SIGTERM);
788 if (CONFIG_FEATURE_KILL_DELAY) {
789 /* NB: parent will wait in NOMMU case */
790 if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
791 sleep(CONFIG_FEATURE_KILL_DELAY);
792 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100793 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000794 kill(a->pid, SIGKILL);
795 _exit(EXIT_SUCCESS);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000796 }
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000797 }
Denis Vlasenko93b38202009-02-14 20:58:13 +0000798#endif
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000799
Denys Vlasenko6e542492009-11-15 03:07:19 +0100800 /* Remove stale entries and SYSINIT entries.
801 * We never rerun SYSINIT entries anyway,
802 * removing them too saves a few bytes */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000803 nextp = &init_action_list;
804 while ((a = *nextp) != NULL) {
Denys Vlasenko6e542492009-11-15 03:07:19 +0100805 if ((a->action_type & ~SYSINIT) == 0) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000806 *nextp = a->next;
807 free(a);
808 } else {
809 nextp = &a->next;
810 }
Eric Andersen82baf632004-10-08 08:21:54 +0000811 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000812
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000813 /* Not needed: */
814 /* run_actions(RESPAWN | ASKFIRST); */
815 /* - we return to main loop, which does this automagically */
Eric Andersen6fd0e312003-07-22 09:48:56 +0000816}
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000817#endif
Eric Andersen82baf632004-10-08 08:21:54 +0000818
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000819static int check_delayed_sigs(void)
820{
821 int sigs_seen = 0;
822
823 while (1) {
824 smallint sig = bb_got_signal;
825
826 if (!sig)
827 return sigs_seen;
828 bb_got_signal = 0;
829 sigs_seen = 1;
830#if ENABLE_FEATURE_USE_INITTAB
831 if (sig == SIGHUP)
832 reload_inittab();
833#endif
834 if (sig == SIGINT)
835 run_actions(CTRLALTDEL);
836 }
837}
838
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000839int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000840int init_main(int argc UNUSED_PARAM, char **argv)
Eric Andersen0460ff21999-10-25 23:32:44 +0000841{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000842 die_sleep = 30 * 24*60*60; /* if xmalloc would ever die... */
Denis Vlasenko9b1381f2007-01-03 02:56:00 +0000843
Denis Vlasenko1d426652008-03-17 09:09:09 +0000844 if (argv[1] && !strcmp(argv[1], "-q")) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000845 return kill(1, SIGHUP);
Eric Andersen730f8262001-12-17 23:13:08 +0000846 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000847
Denis Vlasenko5cb54b52008-10-21 17:14:26 +0000848 if (!DEBUG_INIT) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000849 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
850 if (getpid() != 1
851 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
852 ) {
853 bb_show_usage();
854 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000855 /* Turn off rebooting via CTL-ALT-DEL - we get a
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000856 * SIGINT on CAD so we can shut things down gracefully... */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000857 reboot(RB_DISABLE_CAD); /* misnomer */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000858 }
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000859
Eric Andersen599e3ce2002-07-03 11:08:10 +0000860 /* Figure out where the default console should be */
861 console_init();
Denis Vlasenkod238a472007-03-05 19:22:04 +0000862 set_sane_term();
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000863 xchdir("/");
Erik Andersene49d5ec2000-02-08 19:58:47 +0000864 setsid();
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000865
866 /* Make sure environs is set to something sane */
867 putenv((char *) "HOME=/");
868 putenv((char *) bb_PATH_root_path);
869 putenv((char *) "SHELL=/bin/sh");
870 putenv((char *) "USER=root"); /* needed? why? */
Rob Landleycba1b962006-07-09 17:28:17 +0000871
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000872 if (argv[1])
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000873 xsetenv("RUNLEVEL", argv[1]);
Rob Landleycba1b962006-07-09 17:28:17 +0000874
Denys Vlasenko6be918d2009-12-14 01:32:11 +0100875#if ENABLE_FEATURE_EXTRA_QUIET
Erik Andersene49d5ec2000-02-08 19:58:47 +0000876 /* Hello world */
Denys Vlasenko6be918d2009-12-14 01:32:11 +0100877 message(L_CONSOLE | L_LOG, "init started: %s", bb_banner);
878#endif
Eric Andersencc8ed391999-10-05 16:24:54 +0000879
Erik Andersene49d5ec2000-02-08 19:58:47 +0000880 /* Make sure there is enough memory to do something useful. */
Rob Landleyc3386a42005-08-30 18:50:37 +0000881 if (ENABLE_SWAPONOFF) {
882 struct sysinfo info;
883
Denis Vlasenko6c622462009-01-29 02:01:04 +0000884 if (sysinfo(&info) == 0
Denys Vlasenko90a99042009-09-06 02:36:23 +0200885 && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024
Denis Vlasenko6c622462009-01-29 02:01:04 +0000886 ) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000887 message(L_CONSOLE, "Low memory, forcing swapon");
Rob Landleyc3386a42005-08-30 18:50:37 +0000888 /* swapon -a requires /proc typically */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +0000889 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
Rob Landleyc3386a42005-08-30 18:50:37 +0000890 /* Try to turn on swap */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +0000891 new_init_action(SYSINIT, "swapon -a", "");
Rob Landleyc3386a42005-08-30 18:50:37 +0000892 run_actions(SYSINIT); /* wait and removing */
893 }
894 }
Erik Andersen9e737252000-01-06 01:16:13 +0000895
Erik Andersene49d5ec2000-02-08 19:58:47 +0000896 /* Check if we are supposed to be in single user mode */
Denis Vlasenko1d426652008-03-17 09:09:09 +0000897 if (argv[1]
Denis Vlasenkobf66fbc2006-12-21 13:23:14 +0000898 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
899 ) {
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000900 /* ??? shouldn't we set RUNLEVEL="b" here? */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000901 /* Start a shell on console */
Glenn L McGrathdc4e75e2003-09-02 02:36:18 +0000902 new_init_action(RESPAWN, bb_default_login_shell, "");
Erik Andersene49d5ec2000-02-08 19:58:47 +0000903 } else {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000904 /* Not in single user mode - see what inittab says */
Eric Andersen8a8fbb81999-10-26 00:18:56 +0000905
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000906 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersene49d5ec2000-02-08 19:58:47 +0000907 * then parse_inittab() simply adds in some default
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000908 * actions(i.e., INIT_SCRIPT and a pair
Erik Andersene49d5ec2000-02-08 19:58:47 +0000909 * of "askfirst" shells */
910 parse_inittab();
Eric Andersend00c2621999-12-07 08:37:31 +0000911 }
Erik Andersen983b51b2000-04-04 18:14:25 +0000912
Denis Vlasenko9b1381f2007-01-03 02:56:00 +0000913#if ENABLE_SELINUX
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000914 if (getenv("SELINUX_INIT") == NULL) {
915 int enforce = 0;
916
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000917 putenv((char*)"SELINUX_INIT=YES");
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000918 if (selinux_init_load_policy(&enforce) == 0) {
Denis Vlasenko4921b542007-02-03 02:17:41 +0000919 BB_EXECVP(argv[0], argv);
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000920 } else if (enforce > 0) {
921 /* SELinux in enforcing mode but load_policy failed */
Denys Vlasenko6331cf02009-11-13 09:08:27 +0100922 message(L_CONSOLE, "can't load SELinux Policy. "
Denis Vlasenkob7167542007-02-27 19:20:00 +0000923 "Machine is in enforcing mode. Halting now.");
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000924 exit(EXIT_FAILURE);
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000925 }
926 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000927#endif
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000928
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000929 /* Make the command line just say "init" - thats all, nothing else */
930 strncpy(argv[0], "init", strlen(argv[0]));
931 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
932 while (*++argv)
933 memset(*argv, 0, strlen(*argv));
Eric Andersen219d6f51999-11-02 19:43:01 +0000934
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000935 /* Set up signal handlers */
936 if (!DEBUG_INIT) {
937 struct sigaction sa;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000938
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000939 bb_signals(0
940 + (1 << SIGUSR1) /* halt */
941 + (1 << SIGTERM) /* reboot */
942 + (1 << SIGUSR2) /* poweroff */
943 , halt_reboot_pwoff);
944 signal(SIGQUIT, restart_handler); /* re-exec another init */
945
946 /* Stop handler must allow only SIGCONT inside itself */
947 memset(&sa, 0, sizeof(sa));
948 sigfillset(&sa.sa_mask);
949 sigdelset(&sa.sa_mask, SIGCONT);
950 sa.sa_handler = stop_handler;
951 /* NB: sa_flags doesn't have SA_RESTART.
952 * It must be able to interrupt wait().
953 */
954 sigaction_set(SIGTSTP, &sa); /* pause */
955 /* Does not work as intended, at least in 2.6.20.
956 * SIGSTOP is simply ignored by init:
957 */
958 sigaction_set(SIGSTOP, &sa); /* pause */
959
960 /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
961 * setting handler without SA_RESTART flag.
962 */
963 bb_signals_recursive_norestart((1 << SIGINT), record_signo);
964 }
965
Denys Vlasenko6e542492009-11-15 03:07:19 +0100966 /* Set up "reread /etc/inittab" handler.
967 * Handler is set up without SA_RESTART, it will interrupt syscalls.
968 */
969 if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
970 bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
971
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000972 /* Now run everything that needs to be run */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000973 /* First run the sysinit command */
Eric Andersen1644db92001-09-05 20:18:15 +0000974 run_actions(SYSINIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000975 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +0000976 /* Next run anything that wants to block */
Eric Andersen1644db92001-09-05 20:18:15 +0000977 run_actions(WAIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000978 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +0000979 /* Next run anything to be run only once */
Eric Andersen0298be82002-03-05 15:12:19 +0000980 run_actions(ONCE);
981
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000982 /* Now run the looping stuff for the rest of forever.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000983 */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000984 while (1) {
Denis Vlasenko47741792009-03-10 16:01:57 +0000985 int maybe_WNOHANG;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000986
Denis Vlasenko47741792009-03-10 16:01:57 +0000987 maybe_WNOHANG = check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000988
989 /* (Re)run the respawn/askfirst stuff */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000990 run_actions(RESPAWN | ASKFIRST);
Denis Vlasenko47741792009-03-10 16:01:57 +0000991 maybe_WNOHANG |= check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000992
993 /* Don't consume all CPU time - sleep a bit */
Eric Andersen0298be82002-03-05 15:12:19 +0000994 sleep(1);
Denis Vlasenko47741792009-03-10 16:01:57 +0000995 maybe_WNOHANG |= check_delayed_sigs();
Eric Andersen0298be82002-03-05 15:12:19 +0000996
Denis Vlasenko47741792009-03-10 16:01:57 +0000997 /* Wait for any child process(es) to exit.
Denys Vlasenko3ed181b2009-07-19 14:29:18 +0200998 *
999 * If check_delayed_sigs above reported that a signal
1000 * was caught, wait will be nonblocking. This ensures
1001 * that if SIGHUP has reloaded inittab, respawn and askfirst
1002 * actions will not be delayed until next child death.
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001003 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001004 if (maybe_WNOHANG)
1005 maybe_WNOHANG = WNOHANG;
1006 while (1) {
1007 pid_t wpid;
1008 struct init_action *a;
1009
Denys Vlasenko3ed181b2009-07-19 14:29:18 +02001010 /* If signals happen _in_ the wait, they interrupt it,
1011 * bb_signals_recursive_norestart set them up that way
1012 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001013 wpid = waitpid(-1, NULL, maybe_WNOHANG);
1014 if (wpid <= 0)
1015 break;
1016
1017 a = mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001018 if (a) {
1019 message(L_LOG, "process '%s' (pid %d) exited. "
1020 "Scheduling for restart.",
1021 a->command, wpid);
Erik Andersene49d5ec2000-02-08 19:58:47 +00001022 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001023 /* See if anyone else is waiting to be reaped */
Denis Vlasenko47741792009-03-10 16:01:57 +00001024 maybe_WNOHANG = WNOHANG;
Erik Andersene49d5ec2000-02-08 19:58:47 +00001025 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001026 } /* while (1) */
Eric Andersencc8ed391999-10-05 16:24:54 +00001027}