blob: 1388c75ccb1dcb9d20c673a92d1d999d26d149dc [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>
Jeremie Koenigf812eac2010-05-27 15:37:32 +020017#ifdef __linux__
Denis Vlasenko5981ba52009-03-19 02:35:44 +000018#include <linux/vt.h>
Jeremie Koenigf812eac2010-05-27 15:37:32 +020019#endif
Denys Vlasenko87fb7202010-04-06 18:49:28 +020020#if ENABLE_FEATURE_UTMP
21# include <utmp.h> /* DEAD_PROCESS */
22#endif
Eric Andersen2c1de612003-04-24 11:41:28 +000023
Jeremie Koenigf812eac2010-05-27 15:37:32 +020024/* Used only for sanitizing purposes in set_sane_term() below. On systems where
25 * the baud rate is stored in a separate field, we can safely disable them. */
26#ifndef CBAUD
27# define CBAUD 0
28# define CBAUDEX 0
29#endif
Denis Vlasenko72c99af2009-01-31 01:03:45 +000030
Denis Vlasenko5cb54b52008-10-21 17:14:26 +000031/* Was a CONFIG_xxx option. A lot of people were building
32 * not fully functional init by switching it on! */
33#define DEBUG_INIT 0
34
Denis Vlasenko6c622462009-01-29 02:01:04 +000035#define COMMAND_SIZE 256
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +000036#define CONSOLE_NAME_SIZE 32
Eric Andersenbd22ed82000-07-08 18:55:24 +000037
Denis Vlasenko72c99af2009-01-31 01:03:45 +000038/* Default sysinit script. */
Erik Andersen96e2abd2000-01-07 11:40:44 +000039#ifndef INIT_SCRIPT
Denis Vlasenko72c99af2009-01-31 01:03:45 +000040#define INIT_SCRIPT "/etc/init.d/rcS"
Erik Andersen96e2abd2000-01-07 11:40:44 +000041#endif
Erik Andersen9c88cac1999-12-30 09:25:17 +000042
Denis Vlasenko72c99af2009-01-31 01:03:45 +000043/* Each type of actions can appear many times. They will be
44 * handled in order. RESTART is an exception, only 1st is used.
45 */
46/* Start these actions first and wait for completion */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000047#define SYSINIT 0x01
Denis Vlasenko72c99af2009-01-31 01:03:45 +000048/* Start these after SYSINIT and wait for completion */
49#define WAIT 0x02
50/* Start these after WAIT and *dont* wait for completion */
51#define ONCE 0x04
52/*
53 * NB: while SYSINIT/WAIT/ONCE are being processed,
Denys Vlasenko6e542492009-11-15 03:07:19 +010054 * SIGHUP ("reread /etc/inittab") will be processed only after
55 * each group of actions. If new inittab adds, say, a SYSINIT action,
56 * it will not be run, since init is already "past SYSINIT stage".
Denis Vlasenko72c99af2009-01-31 01:03:45 +000057 */
58/* Start these after ONCE are started, restart on exit */
59#define RESPAWN 0x08
60/* Like RESPAWN, but wait for <Enter> to be pressed on tty */
61#define ASKFIRST 0x10
62/*
63 * Start these on SIGINT, and wait for completion.
64 * Then go back to respawning RESPAWN and ASKFIRST actions.
65 * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed.
66 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000067#define CTRLALTDEL 0x20
Denis Vlasenko72c99af2009-01-31 01:03:45 +000068/*
69 * Start these before killing all processes in preparation for
70 * running RESTART actions or doing low-level halt/reboot/poweroff
71 * (initiated by SIGUSR1/SIGTERM/SIGUSR2).
72 * Wait for completion before proceeding.
73 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000074#define SHUTDOWN 0x40
Denis Vlasenko72c99af2009-01-31 01:03:45 +000075/*
76 * exec() on SIGQUIT. SHUTDOWN actions are started and waited for,
77 * then all processes are killed, then init exec's 1st RESTART action,
78 * replacing itself by it. If no RESTART action specified,
79 * SIGQUIT has no effect.
80 */
Denis Vlasenkoad4da982008-04-05 04:24:23 +000081#define RESTART 0x80
Erik Andersen7dc16072000-01-04 01:10:25 +000082
Denis Vlasenko72c99af2009-01-31 01:03:45 +000083
84/* A linked list of init_actions, to be read from inittab */
Eric Andersen0298be82002-03-05 15:12:19 +000085struct init_action {
Eric Andersen0298be82002-03-05 15:12:19 +000086 struct init_action *next;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +000087 pid_t pid;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +000088 uint8_t action_type;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +000089 char terminal[CONSOLE_NAME_SIZE];
Denis Vlasenkoa37e7132008-02-19 02:57:07 +000090 char command[COMMAND_SIZE];
Erik Andersen7dc16072000-01-04 01:10:25 +000091};
Erik Andersen7dc16072000-01-04 01:10:25 +000092
Eric Andersen0298be82002-03-05 15:12:19 +000093static struct init_action *init_action_list = NULL;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +000094
Denis Vlasenko4c978632007-02-03 03:31:13 +000095static const char *log_console = VC_5;
Rob Landleybc68cd12006-03-10 19:22:06 +000096
97enum {
Denis Vlasenkoec27feb2007-02-17 15:52:02 +000098 L_LOG = 0x1,
99 L_CONSOLE = 0x2,
Rob Landleybc68cd12006-03-10 19:22:06 +0000100#ifndef RB_HALT_SYSTEM
Bernhard Reutner-Fischercf1f2ac2006-06-02 10:43:17 +0000101 RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
Rob Landleybc68cd12006-03-10 19:22:06 +0000102 RB_ENABLE_CAD = 0x89abcdef,
103 RB_DISABLE_CAD = 0,
104 RB_POWER_OFF = 0x4321fedc,
105 RB_AUTOBOOT = 0x01234567,
Eric Andersen0298be82002-03-05 15:12:19 +0000106#endif
Rob Landleybc68cd12006-03-10 19:22:06 +0000107};
Erik Andersen42094cd2000-03-20 21:34:52 +0000108
Erik Andersen42094cd2000-03-20 21:34:52 +0000109/* Print a message to the specified device.
Denis Vlasenko671ca332008-02-19 14:13:20 +0000110 * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
111 * NB: careful, we can be called after vfork!
112 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000113#define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
Denis Vlasenko671ca332008-02-19 14:13:20 +0000114static void message(int where, const char *fmt, ...)
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000115 __attribute__ ((format(printf, 2, 3)));
Denis Vlasenko671ca332008-02-19 14:13:20 +0000116static void message(int where, const char *fmt, ...)
Eric Andersen0460ff21999-10-25 23:32:44 +0000117{
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000118 va_list arguments;
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000119 unsigned l;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000120 char msg[128];
121
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000122 msg[0] = '\r';
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000123 va_start(arguments, fmt);
Denis Vlasenko1bcdcd22008-12-09 21:23:31 +0000124 l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
125 if (l > sizeof(msg) - 1)
126 l = sizeof(msg) - 1;
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000127 va_end(arguments);
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000128
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000129#if ENABLE_FEATURE_INIT_SYSLOG
130 msg[l] = '\0';
131 if (where & L_LOG) {
132 /* Log the message to syslogd */
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100133 openlog(applet_name, 0, LOG_DAEMON);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000134 /* don't print "\r" */
135 syslog(LOG_INFO, "%s", msg + 1);
136 closelog();
137 }
138 msg[l++] = '\n';
139 msg[l] = '\0';
140#else
141 {
142 static int log_fd = -1;
143
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000144 msg[l++] = '\n';
145 msg[l] = '\0';
146 /* Take full control of the log tty, and never close it.
147 * It's mine, all mine! Muhahahaha! */
148 if (log_fd < 0) {
149 if (!log_console) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000150 log_fd = STDERR_FILENO;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000151 } else {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000152 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
153 if (log_fd < 0) {
154 bb_error_msg("can't log to %s", log_console);
Denis Vlasenko671ca332008-02-19 14:13:20 +0000155 where = L_CONSOLE;
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000156 } else {
157 close_on_exec_on(log_fd);
158 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000159 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000160 }
Denis Vlasenko671ca332008-02-19 14:13:20 +0000161 if (where & L_LOG) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000162 full_write(log_fd, msg, l);
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000163 if (log_fd == STDERR_FILENO)
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000164 return; /* don't print dup messages */
165 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000166 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000167#endif
Eric Andersen4c781471999-11-26 08:12:56 +0000168
Denis Vlasenko671ca332008-02-19 14:13:20 +0000169 if (where & L_CONSOLE) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000170 /* Send console messages to console so people will see them. */
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000171 full_write(STDERR_FILENO, msg, l);
Eric Andersen3ae0c781999-11-04 01:13:21 +0000172 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000173}
174
Eric Andersen74400cc2001-10-18 04:11:39 +0000175static void console_init(void)
Eric Andersen0460ff21999-10-25 23:32:44 +0000176{
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200177#ifdef VT_OPENQRY
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000178 int vtno;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200179#endif
Erik Andersene49d5ec2000-02-08 19:58:47 +0000180 char *s;
Eric Andersen0460ff21999-10-25 23:32:44 +0000181
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000182 s = getenv("CONSOLE");
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000183 if (!s)
184 s = getenv("console");
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000185 if (s) {
186 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
187 if (fd >= 0) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000188 dup2(fd, STDIN_FILENO);
189 dup2(fd, STDOUT_FILENO);
190 xmove_fd(fd, STDERR_FILENO);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000191 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000192 dbg_message(L_LOG, "console='%s'", s);
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000193 } else {
Denis Vlasenkofb274df2008-03-17 13:26:51 +0000194 /* Make sure fd 0,1,2 are not closed
195 * (so that they won't be used by future opens) */
Denis Vlasenkod48e81f2008-07-06 07:00:11 +0000196 bb_sanitize_stdio();
Denis Vlasenkoa34b8a42008-11-29 23:14:37 +0000197// Users report problems
198// /* Make sure init can't be blocked by writing to stderr */
199// fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
Eric Andersen07e52971999-11-07 07:38:08 +0000200 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000201
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000202 s = getenv("TERM");
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200203#ifdef VT_OPENQRY
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000204 if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) {
205 /* Not a linux terminal, probably serial console.
206 * Force the TERM setting to vt102
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000207 * if TERM is set to linux (the default) */
208 if (!s || strcmp(s, "linux") == 0)
209 putenv((char*)"TERM=vt102");
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000210 if (!ENABLE_FEATURE_INIT_SYSLOG)
211 log_console = NULL;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200212 } else
213#endif
214 if (!s)
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000215 putenv((char*)"TERM=linux");
Eric Andersen0460ff21999-10-25 23:32:44 +0000216}
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000217
Denis Vlasenko671ca332008-02-19 14:13:20 +0000218/* Set terminal settings to reasonable defaults.
219 * NB: careful, we can be called after vfork! */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000220static void set_sane_term(void)
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000221{
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000222 struct termios tty;
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000223
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000224 tcgetattr(STDIN_FILENO, &tty);
225
226 /* set control chars */
227 tty.c_cc[VINTR] = 3; /* C-c */
228 tty.c_cc[VQUIT] = 28; /* C-\ */
229 tty.c_cc[VERASE] = 127; /* C-? */
230 tty.c_cc[VKILL] = 21; /* C-u */
231 tty.c_cc[VEOF] = 4; /* C-d */
232 tty.c_cc[VSTART] = 17; /* C-q */
233 tty.c_cc[VSTOP] = 19; /* C-s */
234 tty.c_cc[VSUSP] = 26; /* C-z */
235
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200236#ifdef __linux__
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000237 /* use line discipline 0 */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000238 tty.c_line = 0;
Jeremie Koenigf812eac2010-05-27 15:37:32 +0200239#endif
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000240
241 /* Make it be sane */
242 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
243 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
244
245 /* input modes */
246 tty.c_iflag = ICRNL | IXON | IXOFF;
247
248 /* output modes */
249 tty.c_oflag = OPOST | ONLCR;
250
251 /* local modes */
252 tty.c_lflag =
253 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
254
Denis Vlasenko202ac502008-11-05 13:20:58 +0000255 tcsetattr_stdin_TCSANOW(&tty);
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000256}
257
Denis Vlasenko671ca332008-02-19 14:13:20 +0000258/* Open the new terminal device.
259 * NB: careful, we can be called after vfork! */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000260static int open_stdio_to_tty(const char* tty_name)
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000261{
262 /* empty tty_name means "use init's tty", else... */
263 if (tty_name[0]) {
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000264 int fd;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000265
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000266 close(STDIN_FILENO);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000267 /* fd can be only < 0 or 0: */
268 fd = device_open(tty_name, O_RDWR);
269 if (fd) {
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000270 message(L_LOG | L_CONSOLE, "can't open %s: %s",
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000271 tty_name, strerror(errno));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000272 return 0; /* failure */
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000273 }
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000274 dup2(STDIN_FILENO, STDOUT_FILENO);
275 dup2(STDIN_FILENO, STDERR_FILENO);
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000276 }
Denis Vlasenkod238a472007-03-05 19:22:04 +0000277 set_sane_term();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000278 return 1; /* success */
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000279}
280
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100281static void reset_sighandlers_and_unblock_sigs(void)
282{
283 bb_signals(0
284 + (1 << SIGUSR1)
285 + (1 << SIGUSR2)
286 + (1 << SIGTERM)
287 + (1 << SIGQUIT)
288 + (1 << SIGINT)
289 + (1 << SIGHUP)
290 + (1 << SIGTSTP)
Denys Vlasenko18f89122009-12-14 03:08:30 +0100291 + (1 << SIGSTOP)
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100292 , SIG_DFL);
293 sigprocmask_allsigs(SIG_UNBLOCK);
294}
295
Denis Vlasenko671ca332008-02-19 14:13:20 +0000296/* Wrapper around exec:
297 * Takes string (max COMMAND_SIZE chars).
298 * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
299 * Otherwise splits words on whitespace, deals with leading dash,
300 * and uses plain exec().
301 * NB: careful, we can be called after vfork!
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000302 */
303static void init_exec(const char *command)
304{
305 char *cmd[COMMAND_SIZE / 2];
306 char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000307 int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000308
309 /* See if any special /bin/sh requiring characters are present */
310 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
311 strcpy(buf, "exec ");
312 strcpy(buf + 5, command + dash); /* excluding "-" */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000313 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000314 cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
315 cmd[1] = (char*)"-c";
316 cmd[2] = buf;
317 cmd[3] = NULL;
318 } else {
319 /* Convert command (char*) into cmd (char**, one word per string) */
320 char *word, *next;
321 int i = 0;
322 next = strcpy(buf, command); /* including "-" */
323 while ((word = strsep(&next, " \t")) != NULL) {
324 if (*word != '\0') { /* not two spaces/tabs together? */
325 cmd[i] = word;
326 i++;
327 }
328 }
329 cmd[i] = NULL;
330 }
331 /* If we saw leading "-", it is interactive shell.
332 * Try harder to give it a controlling tty.
333 * And skip "-" in actual exec call. */
334 if (dash) {
335 /* _Attempt_ to make stdin a controlling tty. */
336 if (ENABLE_FEATURE_INIT_SCTTY)
337 ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
338 }
339 BB_EXECVP(cmd[0] + dash, cmd);
Denys Vlasenko6331cf02009-11-13 09:08:27 +0100340 message(L_LOG | L_CONSOLE, "can't run '%s': %s", cmd[0], strerror(errno));
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000341 /* returns if execvp fails */
342}
343
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000344/* Used only by run_actions */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000345static pid_t run(const struct init_action *a)
Eric Andersen0298be82002-03-05 15:12:19 +0000346{
Mike Frysinger10427ab2005-07-06 05:00:48 +0000347 pid_t pid;
Erik Andersenac6e71f2000-01-08 22:04:33 +0000348
Denis Vlasenko47741792009-03-10 16:01:57 +0000349 /* Careful: don't be affected by a signal in vforked child */
350 sigprocmask_allsigs(SIG_BLOCK);
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000351 if (BB_MMU && (a->action_type & ASKFIRST))
352 pid = fork();
353 else
354 pid = vfork();
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000355 if (pid < 0)
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000356 message(L_LOG | L_CONSOLE, "can't fork");
Denis Vlasenko47741792009-03-10 16:01:57 +0000357 if (pid) {
358 sigprocmask_allsigs(SIG_UNBLOCK);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000359 return pid; /* Parent or error */
Denis Vlasenko47741792009-03-10 16:01:57 +0000360 }
Eric Andersen0298be82002-03-05 15:12:19 +0000361
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000362 /* Child */
363
Denis Vlasenko966bb432007-02-27 19:20:33 +0000364 /* Reset signal handlers that were set by the parent process */
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100365 reset_sighandlers_and_unblock_sigs();
Eric Andersen2f6c04f1999-11-01 23:59:44 +0000366
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000367 /* Create a new session and make ourself the process group leader */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000368 setsid();
Eric Andersen599e3ce2002-07-03 11:08:10 +0000369
Denis Vlasenko966bb432007-02-27 19:20:33 +0000370 /* Open the new terminal device */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000371 if (!open_stdio_to_tty(a->terminal))
372 _exit(EXIT_FAILURE);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000373
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000374 /* NB: on NOMMU we can't wait for input in child, so
375 * "askfirst" will work the same as "respawn". */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000376 if (BB_MMU && (a->action_type & ASKFIRST)) {
Denis Vlasenko6ca409e2007-08-12 20:58:27 +0000377 static const char press_enter[] ALIGN1 =
Denis Vlasenko966bb432007-02-27 19:20:33 +0000378#ifdef CUSTOMIZED_BANNER
379#include CUSTOMIZED_BANNER
Eric Andersen1f50e842004-08-16 09:29:42 +0000380#endif
Denis Vlasenko966bb432007-02-27 19:20:33 +0000381 "\nPlease press Enter to activate this console. ";
382 char c;
383 /*
384 * Save memory by not exec-ing anything large (like a shell)
385 * before the user wants it. This is critical if swap is not
386 * enabled and the system has low memory. Generally this will
387 * be run on the second virtual console, and the first will
388 * be allowed to start a shell or whatever an init script
389 * specifies.
390 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000391 dbg_message(L_LOG, "waiting for enter to start '%s'"
Denis Vlasenko966bb432007-02-27 19:20:33 +0000392 "(pid %d, tty '%s')\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000393 a->command, getpid(), a->terminal);
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000394 full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
395 while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000396 continue;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000397 }
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000398
Denis Vlasenko6c622462009-01-29 02:01:04 +0000399 /*
400 * When a file named /.init_enable_core exists, setrlimit is called
401 * before processes are spawned to set core file size as unlimited.
402 * This is for debugging only. Don't use this is production, unless
403 * you want core dumps lying about....
404 */
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000405 if (ENABLE_FEATURE_INIT_COREDUMPS) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000406 if (access("/.init_enable_core", F_OK) == 0) {
Denis Vlasenko966bb432007-02-27 19:20:33 +0000407 struct rlimit limit;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000408 limit.rlim_cur = RLIM_INFINITY;
409 limit.rlim_max = RLIM_INFINITY;
410 setrlimit(RLIMIT_CORE, &limit);
Erik Andersen983b51b2000-04-04 18:14:25 +0000411 }
Erik Andersen05df2392000-01-13 04:43:48 +0000412 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000413
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000414 /* Log the process name and args */
415 message(L_LOG, "starting pid %d, tty '%s': '%s'",
416 getpid(), a->terminal, a->command);
417
Denis Vlasenko966bb432007-02-27 19:20:33 +0000418 /* Now run it. The new program will take over this PID,
419 * so nothing further in init.c should be run. */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000420 init_exec(a->command);
Denis Vlasenko966bb432007-02-27 19:20:33 +0000421 /* We're still here? Some error happened. */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000422 _exit(-1);
Eric Andersen0460ff21999-10-25 23:32:44 +0000423}
424
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000425static struct init_action *mark_terminated(pid_t pid)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000426{
427 struct init_action *a;
428
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000429 if (pid > 0) {
430 for (a = init_action_list; a; a = a->next) {
431 if (a->pid == pid) {
432 a->pid = 0;
433 return a;
434 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000435 }
Denys Vlasenko87fb7202010-04-06 18:49:28 +0200436 update_utmp(pid, DEAD_PROCESS, /*tty_name:*/ NULL, /*username:*/ NULL, /*hostname:*/ NULL);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000437 }
438 return NULL;
439}
440
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000441static void waitfor(pid_t pid)
442{
443 /* waitfor(run(x)): protect against failed fork inside run() */
444 if (pid <= 0)
445 return;
446
447 /* Wait for any child (prevent zombies from exiting orphaned processes)
448 * but exit the loop only when specified one has exited. */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000449 while (1) {
450 pid_t wpid = wait(NULL);
451 mark_terminated(wpid);
452 /* Unsafe. SIGTSTP handler might have wait'ed it already */
453 /*if (wpid == pid) break;*/
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000454 /* More reliable: */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000455 if (kill(pid, 0))
456 break;
457 }
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000458}
459
Eric Andersen0298be82002-03-05 15:12:19 +0000460/* Run all commands of a particular type */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000461static void run_actions(int action_type)
Eric Andersen219d6f51999-11-02 19:43:01 +0000462{
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000463 struct init_action *a;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000464
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000465 for (a = init_action_list; a; a = a->next) {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000466 if (!(a->action_type & action_type))
467 continue;
Eric Andersen5222d312002-07-03 05:15:23 +0000468
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000469 if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
470 pid_t pid = run(a);
471 if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
472 waitfor(pid);
473 }
474 if (a->action_type & (RESPAWN | ASKFIRST)) {
475 /* Only run stuff with pid == 0. If pid != 0,
476 * it is already running
477 */
478 if (a->pid == 0)
479 a->pid = run(a);
Eric Andersen730f8262001-12-17 23:13:08 +0000480 }
481 }
482}
483
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000484static void new_init_action(uint8_t action_type, const char *command, const char *cons)
Erik Andersen7dc16072000-01-04 01:10:25 +0000485{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000486 struct init_action *a, **nextp;
Erik Andersen9e737252000-01-06 01:16:13 +0000487
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000488 /* Scenario:
489 * old inittab:
490 * ::shutdown:umount -a -r
491 * ::shutdown:swapoff -a
492 * new inittab:
493 * ::shutdown:swapoff -a
494 * ::shutdown:umount -a -r
495 * On reload, we must ensure entries end up in correct order.
496 * To achieve that, if we find a matching entry, we move it
497 * to the end.
498 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000499 nextp = &init_action_list;
500 while ((a = *nextp) != NULL) {
501 /* Don't enter action if it's already in the list,
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000502 * This prevents losing running RESPAWNs.
503 */
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100504 if (strcmp(a->command, command) == 0
505 && strcmp(a->terminal, cons) == 0
Denis Vlasenkob74a2db2008-07-21 21:34:51 +0000506 ) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000507 /* Remove from list */
508 *nextp = a->next;
509 /* Find the end of the list */
510 while (*nextp != NULL)
511 nextp = &(*nextp)->next;
512 a->next = NULL;
513 break;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000514 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000515 nextp = &a->next;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000516 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000517
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000518 if (!a)
519 a = xzalloc(sizeof(*a));
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000520 /* Append to the end of the list */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000521 *nextp = a;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000522 a->action_type = action_type;
523 safe_strncpy(a->command, command, sizeof(a->command));
524 safe_strncpy(a->terminal, cons, sizeof(a->terminal));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000525 dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000526 a->command, a->action_type, a->terminal);
Erik Andersen7dc16072000-01-04 01:10:25 +0000527}
528
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000529/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersen9e737252000-01-06 01:16:13 +0000530 * then parse_inittab() simply adds in some default
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000531 * actions(i.e., runs INIT_SCRIPT and then starts a pair
532 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
533 * _is_ defined, but /etc/inittab is missing, this
Erik Andersen812d4662000-01-07 18:30:40 +0000534 * results in the same set of default behaviors.
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000535 */
Eric Andersen3e6ff902001-03-09 21:24:12 +0000536static void parse_inittab(void)
Erik Andersen7dc16072000-01-04 01:10:25 +0000537{
Denis Vlasenko6c622462009-01-29 02:01:04 +0000538#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000539 char *token[4];
Denis Vlasenko6c622462009-01-29 02:01:04 +0000540 parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000541
Denis Vlasenko6c622462009-01-29 02:01:04 +0000542 if (parser == NULL)
543#endif
544 {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000545 /* No inittab file - set up some default behavior */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000546 /* Reboot on Ctrl-Alt-Del */
547 new_init_action(CTRLALTDEL, "reboot", "");
548 /* Umount all filesystems on halt/reboot */
549 new_init_action(SHUTDOWN, "umount -a -r", "");
550 /* Swapoff on halt/reboot */
551 if (ENABLE_SWAPONOFF)
552 new_init_action(SHUTDOWN, "swapoff -a", "");
553 /* Prepare to restart init when a QUIT is received */
554 new_init_action(RESTART, "init", "");
555 /* Askfirst shell on tty1-4 */
556 new_init_action(ASKFIRST, bb_default_login_shell, "");
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000557//TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000558 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
559 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
560 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
561 /* sysinit */
562 new_init_action(SYSINIT, INIT_SCRIPT, "");
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000563 return;
564 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000565
566#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000567 /* optional_tty:ignored_runlevel:action:command
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000568 * Delims are not to be collapsed and need exactly 4 tokens
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000569 */
Denis Vlasenko084266e2008-07-26 23:08:31 +0000570 while (config_read(parser, token, 4, 0, "#:",
571 PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000572 /* order must correspond to SYSINIT..RESTART constants */
573 static const char actions[] ALIGN1 =
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000574 "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
Denis Vlasenko6c622462009-01-29 02:01:04 +0000575 "ctrlaltdel\0""shutdown\0""restart\0";
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000576 int action;
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000577 char *tty = token[0];
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000578
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000579 if (!token[3]) /* less than 4 tokens */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000580 goto bad_entry;
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000581 action = index_in_strings(actions, token[2]);
582 if (action < 0 || !token[3][0]) /* token[3]: command */
583 goto bad_entry;
584 /* turn .*TTY -> /dev/TTY */
585 if (tty[0]) {
Denys Vlasenkof8d8aa12010-04-06 18:50:05 +0200586 tty = concat_path_file("/dev/", skip_dev_pfx(tty));
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000587 }
588 new_init_action(1 << action, token[3], tty);
589 if (tty[0])
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000590 free(tty);
591 continue;
592 bad_entry:
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000593 message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
594 parser->lineno);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000595 }
596 config_close(parser);
Denis Vlasenko6c622462009-01-29 02:01:04 +0000597#endif
Erik Andersen7dc16072000-01-04 01:10:25 +0000598}
599
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000600static void pause_and_low_level_reboot(unsigned magic) NORETURN;
601static void pause_and_low_level_reboot(unsigned magic)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000602{
603 pid_t pid;
604
605 /* Allow time for last message to reach serial console, etc */
606 sleep(1);
607
608 /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
609 * in linux/kernel/sys.c, which can cause the machine to panic when
610 * the init process exits... */
611 pid = vfork();
612 if (pid == 0) { /* child */
613 reboot(magic);
614 _exit(EXIT_SUCCESS);
615 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000616 while (1)
617 sleep(1);
618}
619
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000620static void run_shutdown_and_kill_processes(void)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000621{
622 /* Run everything to be run at "shutdown". This is done _prior_
623 * to killing everything, in case people wish to use scripts to
624 * shut things down gracefully... */
625 run_actions(SHUTDOWN);
626
627 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
628
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000629 /* Send signals to every process _except_ pid 1 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000630 kill(-1, SIGTERM);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000631 message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000632 sync();
633 sleep(1);
634
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000635 kill(-1, SIGKILL);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000636 message(L_CONSOLE, "Sent SIG%s to all processes", "KILL");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000637 sync();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000638 /*sleep(1); - callers take care about making a pause */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000639}
640
641/* Signal handling by init:
642 *
643 * For process with PID==1, on entry kernel sets all signals to SIG_DFL
644 * and unmasks all signals. However, for process with PID==1,
645 * default action (SIG_DFL) on any signal is to ignore it,
646 * even for special signals SIGKILL and SIGCONT.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000647 * Also, any signal can be caught or blocked.
Denis Vlasenkofc2a4fc2009-01-31 01:07:05 +0000648 * (but SIGSTOP is still handled specially, at least in 2.6.20)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000649 *
650 * We install two kinds of handlers, "immediate" and "delayed".
651 *
652 * Immediate handlers execute at any time, even while, say, sysinit
653 * is running.
654 *
655 * Delayed handlers just set a flag variable. The variable is checked
656 * in the main loop and acted upon.
657 *
658 * halt/poweroff/reboot and restart have immediate handlers.
659 * They only traverse linked list of struct action's, never modify it,
660 * this should be safe to do even in signal handler. Also they
661 * never return.
662 *
663 * SIGSTOP and SIGTSTP have immediate handlers. They just wait
664 * for SIGCONT to happen.
665 *
666 * SIGHUP has a delayed handler, because modifying linked list
667 * of struct action's from a signal handler while it is manipulated
668 * by the program may be disastrous.
669 *
670 * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
671 * it to happen even somewhere inside "sysinit" would be a bit awkward.
672 *
673 * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
Denis Vlasenko93b38202009-02-14 20:58:13 +0000674 * and only one will be remembered and acted upon.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000675 */
676
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100677/* The SIGUSR[12]/SIGTERM handler */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000678static void halt_reboot_pwoff(int sig) NORETURN;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000679static void halt_reboot_pwoff(int sig)
680{
681 const char *m;
682 unsigned rb;
683
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100684 /* We may call run() and it unmasks signals,
685 * including the one masked inside this signal handler.
686 * Testcase which would start multiple reboot scripts:
687 * while true; do reboot; done
688 * Preventing it:
689 */
690 reset_sighandlers_and_unblock_sigs();
691
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000692 run_shutdown_and_kill_processes();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000693
694 m = "halt";
695 rb = RB_HALT_SYSTEM;
696 if (sig == SIGTERM) {
697 m = "reboot";
698 rb = RB_AUTOBOOT;
699 } else if (sig == SIGUSR2) {
700 m = "poweroff";
701 rb = RB_POWER_OFF;
702 }
703 message(L_CONSOLE, "Requesting system %s", m);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000704 pause_and_low_level_reboot(rb);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000705 /* not reached */
706}
707
Denys Vlasenkobcc6ec92009-12-14 03:03:29 +0100708/* Handler for QUIT - exec "restart" action,
709 * else (no such action defined) do nothing */
710static void restart_handler(int sig UNUSED_PARAM)
711{
712 struct init_action *a;
713
714 for (a = init_action_list; a; a = a->next) {
715 if (!(a->action_type & RESTART))
716 continue;
717
718 /* Starting from here, we won't return.
719 * Thus don't need to worry about preserving errno
720 * and such.
721 */
722
723 reset_sighandlers_and_unblock_sigs();
724
725 run_shutdown_and_kill_processes();
726
727 /* Allow Ctrl-Alt-Del to reboot the system.
728 * This is how kernel sets it up for init, we follow suit.
729 */
730 reboot(RB_ENABLE_CAD); /* misnomer */
731
732 if (open_stdio_to_tty(a->terminal)) {
733 dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
734 /* Theoretically should be safe.
735 * But in practice, kernel bugs may leave
736 * unkillable processes, and wait() may block forever.
737 * Oh well. Hoping "new" init won't be too surprised
738 * by having children it didn't create.
739 */
740 //while (wait(NULL) > 0)
741 // continue;
742 init_exec(a->command);
743 }
744 /* Open or exec failed */
745 pause_and_low_level_reboot(RB_HALT_SYSTEM);
746 /* not reached */
747 }
748}
749
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000750/* The SIGSTOP/SIGTSTP handler
751 * NB: inside it, all signals except SIGCONT are masked
752 * via appropriate setup in sigaction().
753 */
754static void stop_handler(int sig UNUSED_PARAM)
755{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000756 smallint saved_bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000757 int saved_errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000758
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000759 saved_bb_got_signal = bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000760 saved_errno = errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000761 signal(SIGCONT, record_signo);
762
763 while (1) {
764 pid_t wpid;
765
766 if (bb_got_signal == SIGCONT)
767 break;
768 /* NB: this can accidentally wait() for a process
769 * which we waitfor() elsewhere! waitfor() must have
770 * code which is resilient against this.
771 */
772 wpid = wait_any_nohang(NULL);
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000773 mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000774 sleep(1);
775 }
776
777 signal(SIGCONT, SIG_DFL);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000778 errno = saved_errno;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000779 bb_got_signal = saved_bb_got_signal;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000780}
781
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000782#if ENABLE_FEATURE_USE_INITTAB
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000783static void reload_inittab(void)
Eric Andersen6fd0e312003-07-22 09:48:56 +0000784{
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000785 struct init_action *a, **nextp;
Eric Andersen82baf632004-10-08 08:21:54 +0000786
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000787 message(L_LOG, "reloading /etc/inittab");
Eric Andersen82baf632004-10-08 08:21:54 +0000788
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000789 /* Disable old entries */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000790 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100791 a->action_type = 0;
Eric Andersen82baf632004-10-08 08:21:54 +0000792
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000793 /* Append new entries, or modify existing entries
Denys Vlasenko6e542492009-11-15 03:07:19 +0100794 * (incl. setting a->action_type) if cmd and device name
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000795 * match new ones. End result: only entries with
Denys Vlasenko6e542492009-11-15 03:07:19 +0100796 * a->action_type == 0 are stale.
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000797 */
Eric Andersen82baf632004-10-08 08:21:54 +0000798 parse_inittab();
799
Denis Vlasenko93b38202009-02-14 20:58:13 +0000800#if ENABLE_FEATURE_KILL_REMOVED
801 /* Kill stale entries */
802 /* Be nice and send SIGTERM first */
803 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100804 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000805 kill(a->pid, SIGTERM);
806 if (CONFIG_FEATURE_KILL_DELAY) {
807 /* NB: parent will wait in NOMMU case */
808 if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
809 sleep(CONFIG_FEATURE_KILL_DELAY);
810 for (a = init_action_list; a; a = a->next)
Denys Vlasenko6e542492009-11-15 03:07:19 +0100811 if (a->action_type == 0 && a->pid != 0)
Denis Vlasenko93b38202009-02-14 20:58:13 +0000812 kill(a->pid, SIGKILL);
813 _exit(EXIT_SUCCESS);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000814 }
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000815 }
Denis Vlasenko93b38202009-02-14 20:58:13 +0000816#endif
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000817
Denys Vlasenko6e542492009-11-15 03:07:19 +0100818 /* Remove stale entries and SYSINIT entries.
819 * We never rerun SYSINIT entries anyway,
820 * removing them too saves a few bytes */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000821 nextp = &init_action_list;
822 while ((a = *nextp) != NULL) {
Denys Vlasenko6e542492009-11-15 03:07:19 +0100823 if ((a->action_type & ~SYSINIT) == 0) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000824 *nextp = a->next;
825 free(a);
826 } else {
827 nextp = &a->next;
828 }
Eric Andersen82baf632004-10-08 08:21:54 +0000829 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000830
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000831 /* Not needed: */
832 /* run_actions(RESPAWN | ASKFIRST); */
833 /* - we return to main loop, which does this automagically */
Eric Andersen6fd0e312003-07-22 09:48:56 +0000834}
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000835#endif
Eric Andersen82baf632004-10-08 08:21:54 +0000836
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000837static int check_delayed_sigs(void)
838{
839 int sigs_seen = 0;
840
841 while (1) {
842 smallint sig = bb_got_signal;
843
844 if (!sig)
845 return sigs_seen;
846 bb_got_signal = 0;
847 sigs_seen = 1;
848#if ENABLE_FEATURE_USE_INITTAB
849 if (sig == SIGHUP)
850 reload_inittab();
851#endif
852 if (sig == SIGINT)
853 run_actions(CTRLALTDEL);
854 }
855}
856
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000857int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000858int init_main(int argc UNUSED_PARAM, char **argv)
Eric Andersen0460ff21999-10-25 23:32:44 +0000859{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000860 die_sleep = 30 * 24*60*60; /* if xmalloc would ever die... */
Denis Vlasenko9b1381f2007-01-03 02:56:00 +0000861
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100862 if (argv[1] && strcmp(argv[1], "-q") == 0) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000863 return kill(1, SIGHUP);
Eric Andersen730f8262001-12-17 23:13:08 +0000864 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000865
Denis Vlasenko5cb54b52008-10-21 17:14:26 +0000866 if (!DEBUG_INIT) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000867 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
868 if (getpid() != 1
869 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
870 ) {
871 bb_show_usage();
872 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000873 /* Turn off rebooting via CTL-ALT-DEL - we get a
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000874 * SIGINT on CAD so we can shut things down gracefully... */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000875 reboot(RB_DISABLE_CAD); /* misnomer */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000876 }
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000877
Eric Andersen599e3ce2002-07-03 11:08:10 +0000878 /* Figure out where the default console should be */
879 console_init();
Denis Vlasenkod238a472007-03-05 19:22:04 +0000880 set_sane_term();
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000881 xchdir("/");
Erik Andersene49d5ec2000-02-08 19:58:47 +0000882 setsid();
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000883
884 /* Make sure environs is set to something sane */
885 putenv((char *) "HOME=/");
886 putenv((char *) bb_PATH_root_path);
887 putenv((char *) "SHELL=/bin/sh");
888 putenv((char *) "USER=root"); /* needed? why? */
Rob Landleycba1b962006-07-09 17:28:17 +0000889
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000890 if (argv[1])
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000891 xsetenv("RUNLEVEL", argv[1]);
Rob Landleycba1b962006-07-09 17:28:17 +0000892
Denys Vlasenkod7171c12009-12-15 00:34:59 +0100893#if !ENABLE_FEATURE_EXTRA_QUIET
Erik Andersene49d5ec2000-02-08 19:58:47 +0000894 /* Hello world */
Denys Vlasenko6be918d2009-12-14 01:32:11 +0100895 message(L_CONSOLE | L_LOG, "init started: %s", bb_banner);
896#endif
Eric Andersencc8ed391999-10-05 16:24:54 +0000897
Erik Andersene49d5ec2000-02-08 19:58:47 +0000898 /* Make sure there is enough memory to do something useful. */
Rob Landleyc3386a42005-08-30 18:50:37 +0000899 if (ENABLE_SWAPONOFF) {
900 struct sysinfo info;
901
Denis Vlasenko6c622462009-01-29 02:01:04 +0000902 if (sysinfo(&info) == 0
Denys Vlasenko90a99042009-09-06 02:36:23 +0200903 && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024
Denis Vlasenko6c622462009-01-29 02:01:04 +0000904 ) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000905 message(L_CONSOLE, "Low memory, forcing swapon");
Rob Landleyc3386a42005-08-30 18:50:37 +0000906 /* swapon -a requires /proc typically */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +0000907 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
Rob Landleyc3386a42005-08-30 18:50:37 +0000908 /* Try to turn on swap */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +0000909 new_init_action(SYSINIT, "swapon -a", "");
Rob Landleyc3386a42005-08-30 18:50:37 +0000910 run_actions(SYSINIT); /* wait and removing */
911 }
912 }
Erik Andersen9e737252000-01-06 01:16:13 +0000913
Erik Andersene49d5ec2000-02-08 19:58:47 +0000914 /* Check if we are supposed to be in single user mode */
Denis Vlasenko1d426652008-03-17 09:09:09 +0000915 if (argv[1]
Denys Vlasenko1a8de6f2009-12-14 03:16:28 +0100916 && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1'))
Denis Vlasenkobf66fbc2006-12-21 13:23:14 +0000917 ) {
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000918 /* ??? shouldn't we set RUNLEVEL="b" here? */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000919 /* Start a shell on console */
Glenn L McGrathdc4e75e2003-09-02 02:36:18 +0000920 new_init_action(RESPAWN, bb_default_login_shell, "");
Erik Andersene49d5ec2000-02-08 19:58:47 +0000921 } else {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000922 /* Not in single user mode - see what inittab says */
Eric Andersen8a8fbb81999-10-26 00:18:56 +0000923
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000924 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersene49d5ec2000-02-08 19:58:47 +0000925 * then parse_inittab() simply adds in some default
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000926 * actions(i.e., INIT_SCRIPT and a pair
Erik Andersene49d5ec2000-02-08 19:58:47 +0000927 * of "askfirst" shells */
928 parse_inittab();
Eric Andersend00c2621999-12-07 08:37:31 +0000929 }
Erik Andersen983b51b2000-04-04 18:14:25 +0000930
Denis Vlasenko9b1381f2007-01-03 02:56:00 +0000931#if ENABLE_SELINUX
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000932 if (getenv("SELINUX_INIT") == NULL) {
933 int enforce = 0;
934
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000935 putenv((char*)"SELINUX_INIT=YES");
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000936 if (selinux_init_load_policy(&enforce) == 0) {
Denis Vlasenko4921b542007-02-03 02:17:41 +0000937 BB_EXECVP(argv[0], argv);
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000938 } else if (enforce > 0) {
939 /* SELinux in enforcing mode but load_policy failed */
Denys Vlasenko6331cf02009-11-13 09:08:27 +0100940 message(L_CONSOLE, "can't load SELinux Policy. "
Denis Vlasenkob7167542007-02-27 19:20:00 +0000941 "Machine is in enforcing mode. Halting now.");
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000942 exit(EXIT_FAILURE);
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000943 }
944 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000945#endif
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000946
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000947 /* Make the command line just say "init" - thats all, nothing else */
948 strncpy(argv[0], "init", strlen(argv[0]));
949 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
950 while (*++argv)
951 memset(*argv, 0, strlen(*argv));
Eric Andersen219d6f51999-11-02 19:43:01 +0000952
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000953 /* Set up signal handlers */
954 if (!DEBUG_INIT) {
955 struct sigaction sa;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000956
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000957 bb_signals(0
958 + (1 << SIGUSR1) /* halt */
959 + (1 << SIGTERM) /* reboot */
960 + (1 << SIGUSR2) /* poweroff */
961 , halt_reboot_pwoff);
962 signal(SIGQUIT, restart_handler); /* re-exec another init */
963
964 /* Stop handler must allow only SIGCONT inside itself */
965 memset(&sa, 0, sizeof(sa));
966 sigfillset(&sa.sa_mask);
967 sigdelset(&sa.sa_mask, SIGCONT);
968 sa.sa_handler = stop_handler;
969 /* NB: sa_flags doesn't have SA_RESTART.
970 * It must be able to interrupt wait().
971 */
972 sigaction_set(SIGTSTP, &sa); /* pause */
973 /* Does not work as intended, at least in 2.6.20.
974 * SIGSTOP is simply ignored by init:
975 */
976 sigaction_set(SIGSTOP, &sa); /* pause */
977
978 /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
979 * setting handler without SA_RESTART flag.
980 */
981 bb_signals_recursive_norestart((1 << SIGINT), record_signo);
982 }
983
Denys Vlasenko6e542492009-11-15 03:07:19 +0100984 /* Set up "reread /etc/inittab" handler.
985 * Handler is set up without SA_RESTART, it will interrupt syscalls.
986 */
987 if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
988 bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
989
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000990 /* Now run everything that needs to be run */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000991 /* First run the sysinit command */
Eric Andersen1644db92001-09-05 20:18:15 +0000992 run_actions(SYSINIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000993 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +0000994 /* Next run anything that wants to block */
Eric Andersen1644db92001-09-05 20:18:15 +0000995 run_actions(WAIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000996 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +0000997 /* Next run anything to be run only once */
Eric Andersen0298be82002-03-05 15:12:19 +0000998 run_actions(ONCE);
999
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001000 /* Now run the looping stuff for the rest of forever.
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001001 */
Erik Andersene49d5ec2000-02-08 19:58:47 +00001002 while (1) {
Denis Vlasenko47741792009-03-10 16:01:57 +00001003 int maybe_WNOHANG;
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001004
Denis Vlasenko47741792009-03-10 16:01:57 +00001005 maybe_WNOHANG = check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001006
1007 /* (Re)run the respawn/askfirst stuff */
Denis Vlasenkoad4da982008-04-05 04:24:23 +00001008 run_actions(RESPAWN | ASKFIRST);
Denis Vlasenko47741792009-03-10 16:01:57 +00001009 maybe_WNOHANG |= check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001010
1011 /* Don't consume all CPU time - sleep a bit */
Eric Andersen0298be82002-03-05 15:12:19 +00001012 sleep(1);
Denis Vlasenko47741792009-03-10 16:01:57 +00001013 maybe_WNOHANG |= check_delayed_sigs();
Eric Andersen0298be82002-03-05 15:12:19 +00001014
Denis Vlasenko47741792009-03-10 16:01:57 +00001015 /* Wait for any child process(es) to exit.
Denys Vlasenko3ed181b2009-07-19 14:29:18 +02001016 *
1017 * If check_delayed_sigs above reported that a signal
1018 * was caught, wait will be nonblocking. This ensures
1019 * that if SIGHUP has reloaded inittab, respawn and askfirst
1020 * actions will not be delayed until next child death.
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001021 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001022 if (maybe_WNOHANG)
1023 maybe_WNOHANG = WNOHANG;
1024 while (1) {
1025 pid_t wpid;
1026 struct init_action *a;
1027
Denys Vlasenko3ed181b2009-07-19 14:29:18 +02001028 /* If signals happen _in_ the wait, they interrupt it,
1029 * bb_signals_recursive_norestart set them up that way
1030 */
Denis Vlasenko47741792009-03-10 16:01:57 +00001031 wpid = waitpid(-1, NULL, maybe_WNOHANG);
1032 if (wpid <= 0)
1033 break;
1034
1035 a = mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001036 if (a) {
1037 message(L_LOG, "process '%s' (pid %d) exited. "
1038 "Scheduling for restart.",
1039 a->command, wpid);
Erik Andersene49d5ec2000-02-08 19:58:47 +00001040 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001041 /* See if anyone else is waiting to be reaped */
Denis Vlasenko47741792009-03-10 16:01:57 +00001042 maybe_WNOHANG = WNOHANG;
Erik Andersene49d5ec2000-02-08 19:58:47 +00001043 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001044 } /* while (1) */
Eric Andersencc8ed391999-10-05 16:24:54 +00001045}