blob: 35f64cf8a198a825018074e080fc4557c75d857d [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,
43 * SIGHUP ("reread /etc/inittab") will be ignored.
44 * Rationale: it would be ambiguous whether SYSINIT/WAIT/ONCE
45 * need to be rerun or not.
46 */
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,
Denis Vlasenkob2b2c402009-01-28 23:56:31 +000089 MAYBE_CONSOLE = L_CONSOLE * !ENABLE_FEATURE_EXTRA_QUIET,
Rob Landleybc68cd12006-03-10 19:22:06 +000090#ifndef RB_HALT_SYSTEM
Bernhard Reutner-Fischercf1f2ac2006-06-02 10:43:17 +000091 RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
Rob Landleybc68cd12006-03-10 19:22:06 +000092 RB_ENABLE_CAD = 0x89abcdef,
93 RB_DISABLE_CAD = 0,
94 RB_POWER_OFF = 0x4321fedc,
95 RB_AUTOBOOT = 0x01234567,
Eric Andersen0298be82002-03-05 15:12:19 +000096#endif
Rob Landleybc68cd12006-03-10 19:22:06 +000097};
Erik Andersen42094cd2000-03-20 21:34:52 +000098
Erik Andersen42094cd2000-03-20 21:34:52 +000099/* Print a message to the specified device.
Denis Vlasenko671ca332008-02-19 14:13:20 +0000100 * "where" may be bitwise-or'd from L_LOG | L_CONSOLE
101 * NB: careful, we can be called after vfork!
102 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000103#define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0)
Denis Vlasenko671ca332008-02-19 14:13:20 +0000104static void message(int where, const char *fmt, ...)
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000105 __attribute__ ((format(printf, 2, 3)));
Denis Vlasenko671ca332008-02-19 14:13:20 +0000106static void message(int where, const char *fmt, ...)
Eric Andersen0460ff21999-10-25 23:32:44 +0000107{
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000108 va_list arguments;
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000109 unsigned l;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000110 char msg[128];
111
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000112 msg[0] = '\r';
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000113 va_start(arguments, fmt);
Denis Vlasenko1bcdcd22008-12-09 21:23:31 +0000114 l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
115 if (l > sizeof(msg) - 1)
116 l = sizeof(msg) - 1;
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000117 va_end(arguments);
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000118
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000119#if ENABLE_FEATURE_INIT_SYSLOG
120 msg[l] = '\0';
121 if (where & L_LOG) {
122 /* Log the message to syslogd */
123 openlog("init", 0, LOG_DAEMON);
124 /* don't print "\r" */
125 syslog(LOG_INFO, "%s", msg + 1);
126 closelog();
127 }
128 msg[l++] = '\n';
129 msg[l] = '\0';
130#else
131 {
132 static int log_fd = -1;
133
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000134 msg[l++] = '\n';
135 msg[l] = '\0';
136 /* Take full control of the log tty, and never close it.
137 * It's mine, all mine! Muhahahaha! */
138 if (log_fd < 0) {
139 if (!log_console) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000140 log_fd = STDERR_FILENO;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000141 } else {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000142 log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
143 if (log_fd < 0) {
144 bb_error_msg("can't log to %s", log_console);
Denis Vlasenko671ca332008-02-19 14:13:20 +0000145 where = L_CONSOLE;
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000146 } else {
147 close_on_exec_on(log_fd);
148 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000149 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000150 }
Denis Vlasenko671ca332008-02-19 14:13:20 +0000151 if (where & L_LOG) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000152 full_write(log_fd, msg, l);
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000153 if (log_fd == STDERR_FILENO)
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000154 return; /* don't print dup messages */
155 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000156 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000157#endif
Eric Andersen4c781471999-11-26 08:12:56 +0000158
Denis Vlasenko671ca332008-02-19 14:13:20 +0000159 if (where & L_CONSOLE) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000160 /* Send console messages to console so people will see them. */
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000161 full_write(STDERR_FILENO, msg, l);
Eric Andersen3ae0c781999-11-04 01:13:21 +0000162 }
Eric Andersencc8ed391999-10-05 16:24:54 +0000163}
164
Eric Andersen74400cc2001-10-18 04:11:39 +0000165static void console_init(void)
Eric Andersen0460ff21999-10-25 23:32:44 +0000166{
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000167 int vtno;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000168 char *s;
Eric Andersen0460ff21999-10-25 23:32:44 +0000169
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000170 s = getenv("CONSOLE");
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000171 if (!s)
172 s = getenv("console");
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000173 if (s) {
174 int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
175 if (fd >= 0) {
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000176 dup2(fd, STDIN_FILENO);
177 dup2(fd, STDOUT_FILENO);
178 xmove_fd(fd, STDERR_FILENO);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000179 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000180 dbg_message(L_LOG, "console='%s'", s);
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000181 } else {
Denis Vlasenkofb274df2008-03-17 13:26:51 +0000182 /* Make sure fd 0,1,2 are not closed
183 * (so that they won't be used by future opens) */
Denis Vlasenkod48e81f2008-07-06 07:00:11 +0000184 bb_sanitize_stdio();
Denis Vlasenkoa34b8a42008-11-29 23:14:37 +0000185// Users report problems
186// /* Make sure init can't be blocked by writing to stderr */
187// fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK);
Eric Andersen07e52971999-11-07 07:38:08 +0000188 }
Erik Andersene49d5ec2000-02-08 19:58:47 +0000189
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000190 s = getenv("TERM");
Denis Vlasenko5981ba52009-03-19 02:35:44 +0000191 if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) {
192 /* Not a linux terminal, probably serial console.
193 * Force the TERM setting to vt102
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000194 * if TERM is set to linux (the default) */
195 if (!s || strcmp(s, "linux") == 0)
196 putenv((char*)"TERM=vt102");
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000197 if (!ENABLE_FEATURE_INIT_SYSLOG)
198 log_console = NULL;
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000199 } else if (!s)
200 putenv((char*)"TERM=linux");
Eric Andersen0460ff21999-10-25 23:32:44 +0000201}
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000202
Denis Vlasenko671ca332008-02-19 14:13:20 +0000203/* Set terminal settings to reasonable defaults.
204 * NB: careful, we can be called after vfork! */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000205static void set_sane_term(void)
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000206{
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000207 struct termios tty;
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000208
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000209 tcgetattr(STDIN_FILENO, &tty);
210
211 /* set control chars */
212 tty.c_cc[VINTR] = 3; /* C-c */
213 tty.c_cc[VQUIT] = 28; /* C-\ */
214 tty.c_cc[VERASE] = 127; /* C-? */
215 tty.c_cc[VKILL] = 21; /* C-u */
216 tty.c_cc[VEOF] = 4; /* C-d */
217 tty.c_cc[VSTART] = 17; /* C-q */
218 tty.c_cc[VSTOP] = 19; /* C-s */
219 tty.c_cc[VSUSP] = 26; /* C-z */
220
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000221 /* use line discipline 0 */
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000222 tty.c_line = 0;
223
224 /* Make it be sane */
225 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
226 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
227
228 /* input modes */
229 tty.c_iflag = ICRNL | IXON | IXOFF;
230
231 /* output modes */
232 tty.c_oflag = OPOST | ONLCR;
233
234 /* local modes */
235 tty.c_lflag =
236 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
237
Denis Vlasenko202ac502008-11-05 13:20:58 +0000238 tcsetattr_stdin_TCSANOW(&tty);
Eric Andersen7ef1a5b2001-03-20 17:39:08 +0000239}
240
Denis Vlasenko671ca332008-02-19 14:13:20 +0000241/* Open the new terminal device.
242 * NB: careful, we can be called after vfork! */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000243static int open_stdio_to_tty(const char* tty_name)
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000244{
245 /* empty tty_name means "use init's tty", else... */
246 if (tty_name[0]) {
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000247 int fd;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000248
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000249 close(STDIN_FILENO);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000250 /* fd can be only < 0 or 0: */
251 fd = device_open(tty_name, O_RDWR);
252 if (fd) {
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000253 message(L_LOG | L_CONSOLE, "can't open %s: %s",
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000254 tty_name, strerror(errno));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000255 return 0; /* failure */
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000256 }
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000257 dup2(STDIN_FILENO, STDOUT_FILENO);
258 dup2(STDIN_FILENO, STDERR_FILENO);
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000259 }
Denis Vlasenkod238a472007-03-05 19:22:04 +0000260 set_sane_term();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000261 return 1; /* success */
Bernhard Reutner-Fischer0da069d2006-05-29 12:54:16 +0000262}
263
Denis Vlasenko671ca332008-02-19 14:13:20 +0000264/* Wrapper around exec:
265 * Takes string (max COMMAND_SIZE chars).
266 * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
267 * Otherwise splits words on whitespace, deals with leading dash,
268 * and uses plain exec().
269 * NB: careful, we can be called after vfork!
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000270 */
271static void init_exec(const char *command)
272{
273 char *cmd[COMMAND_SIZE / 2];
274 char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000275 int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000276
277 /* See if any special /bin/sh requiring characters are present */
278 if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
279 strcpy(buf, "exec ");
280 strcpy(buf + 5, command + dash); /* excluding "-" */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000281 /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000282 cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
283 cmd[1] = (char*)"-c";
284 cmd[2] = buf;
285 cmd[3] = NULL;
286 } else {
287 /* Convert command (char*) into cmd (char**, one word per string) */
288 char *word, *next;
289 int i = 0;
290 next = strcpy(buf, command); /* including "-" */
291 while ((word = strsep(&next, " \t")) != NULL) {
292 if (*word != '\0') { /* not two spaces/tabs together? */
293 cmd[i] = word;
294 i++;
295 }
296 }
297 cmd[i] = NULL;
298 }
299 /* If we saw leading "-", it is interactive shell.
300 * Try harder to give it a controlling tty.
301 * And skip "-" in actual exec call. */
302 if (dash) {
303 /* _Attempt_ to make stdin a controlling tty. */
304 if (ENABLE_FEATURE_INIT_SCTTY)
305 ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
306 }
307 BB_EXECVP(cmd[0] + dash, cmd);
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000308 message(L_LOG | L_CONSOLE, "cannot run '%s': %s", cmd[0], strerror(errno));
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000309 /* returns if execvp fails */
310}
311
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000312/* Used only by run_actions */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000313static pid_t run(const struct init_action *a)
Eric Andersen0298be82002-03-05 15:12:19 +0000314{
Mike Frysinger10427ab2005-07-06 05:00:48 +0000315 pid_t pid;
Erik Andersenac6e71f2000-01-08 22:04:33 +0000316
Denis Vlasenko47741792009-03-10 16:01:57 +0000317 /* Careful: don't be affected by a signal in vforked child */
318 sigprocmask_allsigs(SIG_BLOCK);
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000319 if (BB_MMU && (a->action_type & ASKFIRST))
320 pid = fork();
321 else
322 pid = vfork();
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000323 if (pid < 0)
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000324 message(L_LOG | L_CONSOLE, "can't fork");
Denis Vlasenko47741792009-03-10 16:01:57 +0000325 if (pid) {
326 sigprocmask_allsigs(SIG_UNBLOCK);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000327 return pid; /* Parent or error */
Denis Vlasenko47741792009-03-10 16:01:57 +0000328 }
Eric Andersen0298be82002-03-05 15:12:19 +0000329
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000330 /* Child */
331
Denis Vlasenko966bb432007-02-27 19:20:33 +0000332 /* Reset signal handlers that were set by the parent process */
Denis Vlasenko25591c32008-02-16 22:58:56 +0000333 bb_signals(0
334 + (1 << SIGUSR1)
335 + (1 << SIGUSR2)
Denis Vlasenko25591c32008-02-16 22:58:56 +0000336 + (1 << SIGTERM)
Denis Vlasenko25591c32008-02-16 22:58:56 +0000337 + (1 << SIGQUIT)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000338 + (1 << SIGINT)
339 + (1 << SIGHUP)
Denis Vlasenko25591c32008-02-16 22:58:56 +0000340 + (1 << SIGTSTP)
341 , SIG_DFL);
Denis Vlasenko47741792009-03-10 16:01:57 +0000342 sigprocmask_allsigs(SIG_UNBLOCK);
Eric Andersen2f6c04f1999-11-01 23:59:44 +0000343
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000344 /* Create a new session and make ourself the process group leader */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000345 setsid();
Eric Andersen599e3ce2002-07-03 11:08:10 +0000346
Denis Vlasenko966bb432007-02-27 19:20:33 +0000347 /* Open the new terminal device */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000348 if (!open_stdio_to_tty(a->terminal))
349 _exit(EXIT_FAILURE);
Erik Andersene49d5ec2000-02-08 19:58:47 +0000350
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000351 /* NB: on NOMMU we can't wait for input in child, so
352 * "askfirst" will work the same as "respawn". */
Denis Vlasenko671ca332008-02-19 14:13:20 +0000353 if (BB_MMU && (a->action_type & ASKFIRST)) {
Denis Vlasenko6ca409e2007-08-12 20:58:27 +0000354 static const char press_enter[] ALIGN1 =
Denis Vlasenko966bb432007-02-27 19:20:33 +0000355#ifdef CUSTOMIZED_BANNER
356#include CUSTOMIZED_BANNER
Eric Andersen1f50e842004-08-16 09:29:42 +0000357#endif
Denis Vlasenko966bb432007-02-27 19:20:33 +0000358 "\nPlease press Enter to activate this console. ";
359 char c;
360 /*
361 * Save memory by not exec-ing anything large (like a shell)
362 * before the user wants it. This is critical if swap is not
363 * enabled and the system has low memory. Generally this will
364 * be run on the second virtual console, and the first will
365 * be allowed to start a shell or whatever an init script
366 * specifies.
367 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000368 dbg_message(L_LOG, "waiting for enter to start '%s'"
Denis Vlasenko966bb432007-02-27 19:20:33 +0000369 "(pid %d, tty '%s')\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000370 a->command, getpid(), a->terminal);
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000371 full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1);
372 while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n')
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000373 continue;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000374 }
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000375
Denis Vlasenko6c622462009-01-29 02:01:04 +0000376 /*
377 * When a file named /.init_enable_core exists, setrlimit is called
378 * before processes are spawned to set core file size as unlimited.
379 * This is for debugging only. Don't use this is production, unless
380 * you want core dumps lying about....
381 */
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000382 if (ENABLE_FEATURE_INIT_COREDUMPS) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000383 if (access("/.init_enable_core", F_OK) == 0) {
Denis Vlasenko966bb432007-02-27 19:20:33 +0000384 struct rlimit limit;
Denis Vlasenko966bb432007-02-27 19:20:33 +0000385 limit.rlim_cur = RLIM_INFINITY;
386 limit.rlim_max = RLIM_INFINITY;
387 setrlimit(RLIMIT_CORE, &limit);
Erik Andersen983b51b2000-04-04 18:14:25 +0000388 }
Erik Andersen05df2392000-01-13 04:43:48 +0000389 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000390
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000391 /* Log the process name and args */
392 message(L_LOG, "starting pid %d, tty '%s': '%s'",
393 getpid(), a->terminal, a->command);
394
Denis Vlasenko966bb432007-02-27 19:20:33 +0000395 /* Now run it. The new program will take over this PID,
396 * so nothing further in init.c should be run. */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000397 init_exec(a->command);
Denis Vlasenko966bb432007-02-27 19:20:33 +0000398 /* We're still here? Some error happened. */
Denis Vlasenko966bb432007-02-27 19:20:33 +0000399 _exit(-1);
Eric Andersen0460ff21999-10-25 23:32:44 +0000400}
401
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000402static struct init_action *mark_terminated(pid_t pid)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000403{
404 struct init_action *a;
405
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000406 if (pid > 0) {
407 for (a = init_action_list; a; a = a->next) {
408 if (a->pid == pid) {
409 a->pid = 0;
410 return a;
411 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000412 }
413 }
414 return NULL;
415}
416
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000417static void waitfor(pid_t pid)
418{
419 /* waitfor(run(x)): protect against failed fork inside run() */
420 if (pid <= 0)
421 return;
422
423 /* Wait for any child (prevent zombies from exiting orphaned processes)
424 * but exit the loop only when specified one has exited. */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000425 while (1) {
426 pid_t wpid = wait(NULL);
427 mark_terminated(wpid);
428 /* Unsafe. SIGTSTP handler might have wait'ed it already */
429 /*if (wpid == pid) break;*/
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000430 /* More reliable: */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000431 if (kill(pid, 0))
432 break;
433 }
Denis Vlasenkocab28aa2009-01-31 01:02:07 +0000434}
435
Eric Andersen0298be82002-03-05 15:12:19 +0000436/* Run all commands of a particular type */
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000437static void run_actions(int action_type)
Eric Andersen219d6f51999-11-02 19:43:01 +0000438{
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000439 struct init_action *a;
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000440
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000441 for (a = init_action_list; a; a = a->next) {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000442 if (!(a->action_type & action_type))
443 continue;
Eric Andersen5222d312002-07-03 05:15:23 +0000444
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000445 if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) {
446 pid_t pid = run(a);
447 if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN))
448 waitfor(pid);
449 }
450 if (a->action_type & (RESPAWN | ASKFIRST)) {
451 /* Only run stuff with pid == 0. If pid != 0,
452 * it is already running
453 */
454 if (a->pid == 0)
455 a->pid = run(a);
Eric Andersen730f8262001-12-17 23:13:08 +0000456 }
457 }
458}
459
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000460static void new_init_action(uint8_t action_type, const char *command, const char *cons)
Erik Andersen7dc16072000-01-04 01:10:25 +0000461{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000462 struct init_action *a, **nextp;
Erik Andersen9e737252000-01-06 01:16:13 +0000463
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000464 /* Scenario:
465 * old inittab:
466 * ::shutdown:umount -a -r
467 * ::shutdown:swapoff -a
468 * new inittab:
469 * ::shutdown:swapoff -a
470 * ::shutdown:umount -a -r
471 * On reload, we must ensure entries end up in correct order.
472 * To achieve that, if we find a matching entry, we move it
473 * to the end.
474 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000475 nextp = &init_action_list;
476 while ((a = *nextp) != NULL) {
477 /* Don't enter action if it's already in the list,
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000478 * This prevents losing running RESPAWNs.
479 */
Denis Vlasenkoec27feb2007-02-17 15:52:02 +0000480 if ((strcmp(a->command, command) == 0)
Denis Vlasenkob74a2db2008-07-21 21:34:51 +0000481 && (strcmp(a->terminal, cons) == 0)
482 ) {
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000483 /* Remove from list */
484 *nextp = a->next;
485 /* Find the end of the list */
486 while (*nextp != NULL)
487 nextp = &(*nextp)->next;
488 a->next = NULL;
489 break;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000490 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000491 nextp = &a->next;
Eric Andersen6fd0e312003-07-22 09:48:56 +0000492 }
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000493
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000494 if (!a)
495 a = xzalloc(sizeof(*a));
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000496 /* Append to the end of the list */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000497 *nextp = a;
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000498 a->action_type = action_type;
499 safe_strncpy(a->command, command, sizeof(a->command));
500 safe_strncpy(a->terminal, cons, sizeof(a->terminal));
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000501 dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000502 a->command, a->action_type, a->terminal);
Erik Andersen7dc16072000-01-04 01:10:25 +0000503}
504
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000505/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersen9e737252000-01-06 01:16:13 +0000506 * then parse_inittab() simply adds in some default
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000507 * actions(i.e., runs INIT_SCRIPT and then starts a pair
508 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
509 * _is_ defined, but /etc/inittab is missing, this
Erik Andersen812d4662000-01-07 18:30:40 +0000510 * results in the same set of default behaviors.
Glenn L McGrathbaf55a82002-08-22 18:22:10 +0000511 */
Eric Andersen3e6ff902001-03-09 21:24:12 +0000512static void parse_inittab(void)
Erik Andersen7dc16072000-01-04 01:10:25 +0000513{
Denis Vlasenko6c622462009-01-29 02:01:04 +0000514#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000515 char *token[4];
Denis Vlasenko6c622462009-01-29 02:01:04 +0000516 parser_t *parser = config_open2("/etc/inittab", fopen_for_read);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000517
Denis Vlasenko6c622462009-01-29 02:01:04 +0000518 if (parser == NULL)
519#endif
520 {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000521 /* No inittab file - set up some default behavior */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000522 /* Reboot on Ctrl-Alt-Del */
523 new_init_action(CTRLALTDEL, "reboot", "");
524 /* Umount all filesystems on halt/reboot */
525 new_init_action(SHUTDOWN, "umount -a -r", "");
526 /* Swapoff on halt/reboot */
527 if (ENABLE_SWAPONOFF)
528 new_init_action(SHUTDOWN, "swapoff -a", "");
529 /* Prepare to restart init when a QUIT is received */
530 new_init_action(RESTART, "init", "");
531 /* Askfirst shell on tty1-4 */
532 new_init_action(ASKFIRST, bb_default_login_shell, "");
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000533//TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000534 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
535 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
536 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
537 /* sysinit */
538 new_init_action(SYSINIT, INIT_SCRIPT, "");
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000539 return;
540 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000541
542#if ENABLE_FEATURE_USE_INITTAB
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000543 /* optional_tty:ignored_runlevel:action:command
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000544 * Delims are not to be collapsed and need exactly 4 tokens
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000545 */
Denis Vlasenko084266e2008-07-26 23:08:31 +0000546 while (config_read(parser, token, 4, 0, "#:",
547 PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) {
Denis Vlasenko6c622462009-01-29 02:01:04 +0000548 /* order must correspond to SYSINIT..RESTART constants */
549 static const char actions[] ALIGN1 =
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000550 "sysinit\0""wait\0""once\0""respawn\0""askfirst\0"
Denis Vlasenko6c622462009-01-29 02:01:04 +0000551 "ctrlaltdel\0""shutdown\0""restart\0";
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000552 int action;
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000553 char *tty = token[0];
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000554
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000555 if (!token[3]) /* less than 4 tokens */
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000556 goto bad_entry;
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000557 action = index_in_strings(actions, token[2]);
558 if (action < 0 || !token[3][0]) /* token[3]: command */
559 goto bad_entry;
560 /* turn .*TTY -> /dev/TTY */
561 if (tty[0]) {
562 if (strncmp(tty, "/dev/", 5) == 0)
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000563 tty += 5;
564 tty = concat_path_file("/dev/", tty);
Denis Vlasenkoa474b682008-07-17 17:58:44 +0000565 }
566 new_init_action(1 << action, token[3], tty);
567 if (tty[0])
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000568 free(tty);
569 continue;
570 bad_entry:
Bernhard Reutner-Fischerad2fa652008-07-21 11:16:39 +0000571 message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d",
572 parser->lineno);
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000573 }
574 config_close(parser);
Denis Vlasenko6c622462009-01-29 02:01:04 +0000575#endif
Erik Andersen7dc16072000-01-04 01:10:25 +0000576}
577
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000578static void pause_and_low_level_reboot(unsigned magic) NORETURN;
579static void pause_and_low_level_reboot(unsigned magic)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000580{
581 pid_t pid;
582
583 /* Allow time for last message to reach serial console, etc */
584 sleep(1);
585
586 /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS)
587 * in linux/kernel/sys.c, which can cause the machine to panic when
588 * the init process exits... */
589 pid = vfork();
590 if (pid == 0) { /* child */
591 reboot(magic);
592 _exit(EXIT_SUCCESS);
593 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000594 while (1)
595 sleep(1);
596}
597
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000598static void run_shutdown_and_kill_processes(void)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000599{
600 /* Run everything to be run at "shutdown". This is done _prior_
601 * to killing everything, in case people wish to use scripts to
602 * shut things down gracefully... */
603 run_actions(SHUTDOWN);
604
605 message(L_CONSOLE | L_LOG, "The system is going down NOW!");
606
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000607 /* Send signals to every process _except_ pid 1 */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000608 kill(-1, SIGTERM);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000609 message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000610 sync();
611 sleep(1);
612
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000613 kill(-1, SIGKILL);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000614 message(L_CONSOLE, "Sent SIG%s to all processes", "KILL");
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000615 sync();
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000616 /*sleep(1); - callers take care about making a pause */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000617}
618
619/* Signal handling by init:
620 *
621 * For process with PID==1, on entry kernel sets all signals to SIG_DFL
622 * and unmasks all signals. However, for process with PID==1,
623 * default action (SIG_DFL) on any signal is to ignore it,
624 * even for special signals SIGKILL and SIGCONT.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000625 * Also, any signal can be caught or blocked.
Denis Vlasenkofc2a4fc2009-01-31 01:07:05 +0000626 * (but SIGSTOP is still handled specially, at least in 2.6.20)
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000627 *
628 * We install two kinds of handlers, "immediate" and "delayed".
629 *
630 * Immediate handlers execute at any time, even while, say, sysinit
631 * is running.
632 *
633 * Delayed handlers just set a flag variable. The variable is checked
634 * in the main loop and acted upon.
635 *
636 * halt/poweroff/reboot and restart have immediate handlers.
637 * They only traverse linked list of struct action's, never modify it,
638 * this should be safe to do even in signal handler. Also they
639 * never return.
640 *
641 * SIGSTOP and SIGTSTP have immediate handlers. They just wait
642 * for SIGCONT to happen.
643 *
644 * SIGHUP has a delayed handler, because modifying linked list
645 * of struct action's from a signal handler while it is manipulated
646 * by the program may be disastrous.
647 *
648 * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing
649 * it to happen even somewhere inside "sysinit" would be a bit awkward.
650 *
651 * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide
Denis Vlasenko93b38202009-02-14 20:58:13 +0000652 * and only one will be remembered and acted upon.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000653 */
654
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000655static void halt_reboot_pwoff(int sig) NORETURN;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000656static void halt_reboot_pwoff(int sig)
657{
658 const char *m;
659 unsigned rb;
660
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000661 run_shutdown_and_kill_processes();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000662
663 m = "halt";
664 rb = RB_HALT_SYSTEM;
665 if (sig == SIGTERM) {
666 m = "reboot";
667 rb = RB_AUTOBOOT;
668 } else if (sig == SIGUSR2) {
669 m = "poweroff";
670 rb = RB_POWER_OFF;
671 }
672 message(L_CONSOLE, "Requesting system %s", m);
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000673 pause_and_low_level_reboot(rb);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000674 /* not reached */
675}
676
677/* The SIGSTOP/SIGTSTP handler
678 * NB: inside it, all signals except SIGCONT are masked
679 * via appropriate setup in sigaction().
680 */
681static void stop_handler(int sig UNUSED_PARAM)
682{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000683 smallint saved_bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000684 int saved_errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000685
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000686 saved_bb_got_signal = bb_got_signal;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000687 saved_errno = errno;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000688 signal(SIGCONT, record_signo);
689
690 while (1) {
691 pid_t wpid;
692
693 if (bb_got_signal == SIGCONT)
694 break;
695 /* NB: this can accidentally wait() for a process
696 * which we waitfor() elsewhere! waitfor() must have
697 * code which is resilient against this.
698 */
699 wpid = wait_any_nohang(NULL);
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000700 mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000701 sleep(1);
702 }
703
704 signal(SIGCONT, SIG_DFL);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000705 errno = saved_errno;
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000706 bb_got_signal = saved_bb_got_signal;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000707}
708
709/* Handler for QUIT - exec "restart" action,
710 * else (no such action defined) do nothing */
711static void restart_handler(int sig UNUSED_PARAM)
712{
713 struct init_action *a;
714
715 for (a = init_action_list; a; a = a->next) {
716 if (!(a->action_type & RESTART))
717 continue;
718
719 /* Starting from here, we won't return.
720 * Thus don't need to worry about preserving errno
721 * and such.
722 */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000723 run_shutdown_and_kill_processes();
724
725 /* Allow Ctrl-Alt-Del to reboot the system.
726 * This is how kernel sets it up for init, we follow suit.
727 */
728 reboot(RB_ENABLE_CAD); /* misnomer */
729
730 if (open_stdio_to_tty(a->terminal)) {
731 dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command);
Denis Vlasenko9ec0ecb2009-01-31 19:26:12 +0000732 /* Theoretically should be safe.
733 * But in practice, kernel bugs may leave
734 * unkillable processes, and wait() may block forever.
735 * Oh well. Hoping "new" init won't be too surprised
736 * by having children it didn't create.
737 */
738 //while (wait(NULL) > 0)
739 // continue;
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000740 init_exec(a->command);
741 }
742 /* Open or exec failed */
743 pause_and_low_level_reboot(RB_HALT_SYSTEM);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000744 /* not reached */
745 }
746}
747
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000748#if ENABLE_FEATURE_USE_INITTAB
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000749static void reload_inittab(void)
Eric Andersen6fd0e312003-07-22 09:48:56 +0000750{
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000751 struct init_action *a, **nextp;
Eric Andersen82baf632004-10-08 08:21:54 +0000752
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000753 message(L_LOG, "reloading /etc/inittab");
Eric Andersen82baf632004-10-08 08:21:54 +0000754
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000755 /* Disable old entries */
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000756 for (a = init_action_list; a; a = a->next)
Denis Vlasenkoa37e7132008-02-19 02:57:07 +0000757 a->action_type = ONCE;
Eric Andersen82baf632004-10-08 08:21:54 +0000758
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000759 /* Append new entries, or modify existing entries
760 * (set a->action_type) if cmd and device name
761 * match new ones. End result: only entries with
762 * a->action_type == ONCE are stale.
763 */
Eric Andersen82baf632004-10-08 08:21:54 +0000764 parse_inittab();
765
Denis Vlasenko93b38202009-02-14 20:58:13 +0000766#if ENABLE_FEATURE_KILL_REMOVED
767 /* Kill stale entries */
768 /* Be nice and send SIGTERM first */
769 for (a = init_action_list; a; a = a->next)
770 if (a->action_type == ONCE && a->pid != 0)
771 kill(a->pid, SIGTERM);
772 if (CONFIG_FEATURE_KILL_DELAY) {
773 /* NB: parent will wait in NOMMU case */
774 if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
775 sleep(CONFIG_FEATURE_KILL_DELAY);
776 for (a = init_action_list; a; a = a->next)
777 if (a->action_type == ONCE && a->pid != 0)
778 kill(a->pid, SIGKILL);
779 _exit(EXIT_SUCCESS);
Denis Vlasenkod55268d2007-12-26 18:32:58 +0000780 }
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000781 }
Denis Vlasenko93b38202009-02-14 20:58:13 +0000782#endif
Denis Vlasenkoec5631b2007-12-25 01:08:58 +0000783
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000784 /* Remove stale (ONCE) and not useful (SYSINIT,WAIT) entries */
785 nextp = &init_action_list;
786 while ((a = *nextp) != NULL) {
787 if (a->action_type & (ONCE | SYSINIT | WAIT)) {
788 *nextp = a->next;
789 free(a);
790 } else {
791 nextp = &a->next;
792 }
Eric Andersen82baf632004-10-08 08:21:54 +0000793 }
Denis Vlasenko4ae8a052009-01-31 18:55:54 +0000794
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000795 /* Not needed: */
796 /* run_actions(RESPAWN | ASKFIRST); */
797 /* - we return to main loop, which does this automagically */
Eric Andersen6fd0e312003-07-22 09:48:56 +0000798}
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000799#endif
Eric Andersen82baf632004-10-08 08:21:54 +0000800
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000801static int check_delayed_sigs(void)
802{
803 int sigs_seen = 0;
804
805 while (1) {
806 smallint sig = bb_got_signal;
807
808 if (!sig)
809 return sigs_seen;
810 bb_got_signal = 0;
811 sigs_seen = 1;
812#if ENABLE_FEATURE_USE_INITTAB
813 if (sig == SIGHUP)
814 reload_inittab();
815#endif
816 if (sig == SIGINT)
817 run_actions(CTRLALTDEL);
818 }
819}
820
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000821int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000822int init_main(int argc UNUSED_PARAM, char **argv)
Eric Andersen0460ff21999-10-25 23:32:44 +0000823{
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000824 die_sleep = 30 * 24*60*60; /* if xmalloc would ever die... */
Denis Vlasenko9b1381f2007-01-03 02:56:00 +0000825
Denis Vlasenko1d426652008-03-17 09:09:09 +0000826 if (argv[1] && !strcmp(argv[1], "-q")) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000827 return kill(1, SIGHUP);
Eric Andersen730f8262001-12-17 23:13:08 +0000828 }
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000829
Denis Vlasenko5cb54b52008-10-21 17:14:26 +0000830 if (!DEBUG_INIT) {
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000831 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
832 if (getpid() != 1
833 && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
834 ) {
835 bb_show_usage();
836 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000837 /* Turn off rebooting via CTL-ALT-DEL - we get a
Mike Frysingerbb50fdf2007-12-25 04:30:14 +0000838 * SIGINT on CAD so we can shut things down gracefully... */
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000839 reboot(RB_DISABLE_CAD); /* misnomer */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000840 }
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000841
Eric Andersen599e3ce2002-07-03 11:08:10 +0000842 /* Figure out where the default console should be */
843 console_init();
Denis Vlasenkod238a472007-03-05 19:22:04 +0000844 set_sane_term();
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000845 xchdir("/");
Erik Andersene49d5ec2000-02-08 19:58:47 +0000846 setsid();
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000847
848 /* Make sure environs is set to something sane */
849 putenv((char *) "HOME=/");
850 putenv((char *) bb_PATH_root_path);
851 putenv((char *) "SHELL=/bin/sh");
852 putenv((char *) "USER=root"); /* needed? why? */
Rob Landleycba1b962006-07-09 17:28:17 +0000853
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000854 if (argv[1])
Denis Vlasenkob8d1a4c2008-09-20 16:28:59 +0000855 xsetenv("RUNLEVEL", argv[1]);
Rob Landleycba1b962006-07-09 17:28:17 +0000856
Erik Andersene49d5ec2000-02-08 19:58:47 +0000857 /* Hello world */
Denis Vlasenkoca525b42007-06-13 12:27:17 +0000858 message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_banner);
Eric Andersencc8ed391999-10-05 16:24:54 +0000859
Erik Andersene49d5ec2000-02-08 19:58:47 +0000860 /* Make sure there is enough memory to do something useful. */
Rob Landleyc3386a42005-08-30 18:50:37 +0000861 if (ENABLE_SWAPONOFF) {
862 struct sysinfo info;
863
Denis Vlasenko6c622462009-01-29 02:01:04 +0000864 if (sysinfo(&info) == 0
865 && (info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024
866 ) {
Denis Vlasenko7a2ca5e2007-02-21 00:15:20 +0000867 message(L_CONSOLE, "Low memory, forcing swapon");
Rob Landleyc3386a42005-08-30 18:50:37 +0000868 /* swapon -a requires /proc typically */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +0000869 new_init_action(SYSINIT, "mount -t proc proc /proc", "");
Rob Landleyc3386a42005-08-30 18:50:37 +0000870 /* Try to turn on swap */
Denis Vlasenko2f0c0d02007-01-21 00:41:04 +0000871 new_init_action(SYSINIT, "swapon -a", "");
Rob Landleyc3386a42005-08-30 18:50:37 +0000872 run_actions(SYSINIT); /* wait and removing */
873 }
874 }
Erik Andersen9e737252000-01-06 01:16:13 +0000875
Erik Andersene49d5ec2000-02-08 19:58:47 +0000876 /* Check if we are supposed to be in single user mode */
Denis Vlasenko1d426652008-03-17 09:09:09 +0000877 if (argv[1]
Denis Vlasenkobf66fbc2006-12-21 13:23:14 +0000878 && (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
879 ) {
Bernhard Reutner-Fischer54d50a02008-07-17 14:00:42 +0000880 /* ??? shouldn't we set RUNLEVEL="b" here? */
Glenn L McGrathb4a1baa2003-01-13 22:09:50 +0000881 /* Start a shell on console */
Glenn L McGrathdc4e75e2003-09-02 02:36:18 +0000882 new_init_action(RESPAWN, bb_default_login_shell, "");
Erik Andersene49d5ec2000-02-08 19:58:47 +0000883 } else {
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000884 /* Not in single user mode - see what inittab says */
Eric Andersen8a8fbb81999-10-26 00:18:56 +0000885
Eric Andersenbdfd0d72001-10-24 05:00:29 +0000886 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
Erik Andersene49d5ec2000-02-08 19:58:47 +0000887 * then parse_inittab() simply adds in some default
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000888 * actions(i.e., INIT_SCRIPT and a pair
Erik Andersene49d5ec2000-02-08 19:58:47 +0000889 * of "askfirst" shells */
890 parse_inittab();
Eric Andersend00c2621999-12-07 08:37:31 +0000891 }
Erik Andersen983b51b2000-04-04 18:14:25 +0000892
Denis Vlasenko9b1381f2007-01-03 02:56:00 +0000893#if ENABLE_SELINUX
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000894 if (getenv("SELINUX_INIT") == NULL) {
895 int enforce = 0;
896
Denis Vlasenkod8540f72007-06-14 07:53:06 +0000897 putenv((char*)"SELINUX_INIT=YES");
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000898 if (selinux_init_load_policy(&enforce) == 0) {
Denis Vlasenko4921b542007-02-03 02:17:41 +0000899 BB_EXECVP(argv[0], argv);
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000900 } else if (enforce > 0) {
901 /* SELinux in enforcing mode but load_policy failed */
Bernhard Reutner-Fischera53de7f2008-07-21 13:46:54 +0000902 message(L_CONSOLE, "cannot load SELinux Policy. "
Denis Vlasenkob7167542007-02-27 19:20:00 +0000903 "Machine is in enforcing mode. Halting now.");
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000904 exit(EXIT_FAILURE);
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000905 }
906 }
Denis Vlasenko6c622462009-01-29 02:01:04 +0000907#endif
Rob Landleyb3ede5a2006-03-27 23:09:12 +0000908
Denis Vlasenko2afabe82007-12-10 07:06:04 +0000909 /* Make the command line just say "init" - thats all, nothing else */
910 strncpy(argv[0], "init", strlen(argv[0]));
911 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
912 while (*++argv)
913 memset(*argv, 0, strlen(*argv));
Eric Andersen219d6f51999-11-02 19:43:01 +0000914
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000915 /* Set up signal handlers */
916 if (!DEBUG_INIT) {
917 struct sigaction sa;
Erik Andersene49d5ec2000-02-08 19:58:47 +0000918
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000919 bb_signals(0
920 + (1 << SIGUSR1) /* halt */
921 + (1 << SIGTERM) /* reboot */
922 + (1 << SIGUSR2) /* poweroff */
923 , halt_reboot_pwoff);
924 signal(SIGQUIT, restart_handler); /* re-exec another init */
925
926 /* Stop handler must allow only SIGCONT inside itself */
927 memset(&sa, 0, sizeof(sa));
928 sigfillset(&sa.sa_mask);
929 sigdelset(&sa.sa_mask, SIGCONT);
930 sa.sa_handler = stop_handler;
931 /* NB: sa_flags doesn't have SA_RESTART.
932 * It must be able to interrupt wait().
933 */
934 sigaction_set(SIGTSTP, &sa); /* pause */
935 /* Does not work as intended, at least in 2.6.20.
936 * SIGSTOP is simply ignored by init:
937 */
938 sigaction_set(SIGSTOP, &sa); /* pause */
939
940 /* SIGINT (Ctrl-Alt-Del) must interrupt wait(),
941 * setting handler without SA_RESTART flag.
942 */
943 bb_signals_recursive_norestart((1 << SIGINT), record_signo);
944 }
945
946 /* Now run everything that needs to be run */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000947 /* First run the sysinit command */
Eric Andersen1644db92001-09-05 20:18:15 +0000948 run_actions(SYSINIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000949 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +0000950 /* Next run anything that wants to block */
Eric Andersen1644db92001-09-05 20:18:15 +0000951 run_actions(WAIT);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000952 check_delayed_sigs();
Erik Andersene49d5ec2000-02-08 19:58:47 +0000953 /* Next run anything to be run only once */
Eric Andersen0298be82002-03-05 15:12:19 +0000954 run_actions(ONCE);
955
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000956 /* Set up "reread /etc/inittab" handler.
957 * Handler is set up without SA_RESTART, it will interrupt syscalls.
958 */
959 if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB)
960 bb_signals_recursive_norestart((1 << SIGHUP), record_signo);
Eric Andersen82baf632004-10-08 08:21:54 +0000961
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000962 /* Now run the looping stuff for the rest of forever.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000963 */
Erik Andersene49d5ec2000-02-08 19:58:47 +0000964 while (1) {
Denis Vlasenko47741792009-03-10 16:01:57 +0000965 int maybe_WNOHANG;
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000966
Denis Vlasenko47741792009-03-10 16:01:57 +0000967 maybe_WNOHANG = check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000968
969 /* (Re)run the respawn/askfirst stuff */
Denis Vlasenkoad4da982008-04-05 04:24:23 +0000970 run_actions(RESPAWN | ASKFIRST);
Denis Vlasenko47741792009-03-10 16:01:57 +0000971 maybe_WNOHANG |= check_delayed_sigs();
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000972
973 /* Don't consume all CPU time - sleep a bit */
Eric Andersen0298be82002-03-05 15:12:19 +0000974 sleep(1);
Denis Vlasenko47741792009-03-10 16:01:57 +0000975 maybe_WNOHANG |= check_delayed_sigs();
Eric Andersen0298be82002-03-05 15:12:19 +0000976
Denis Vlasenko47741792009-03-10 16:01:57 +0000977 /* Wait for any child process(es) to exit.
Denys Vlasenko3ed181b2009-07-19 14:29:18 +0200978 *
979 * If check_delayed_sigs above reported that a signal
980 * was caught, wait will be nonblocking. This ensures
981 * that if SIGHUP has reloaded inittab, respawn and askfirst
982 * actions will not be delayed until next child death.
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000983 */
Denis Vlasenko47741792009-03-10 16:01:57 +0000984 if (maybe_WNOHANG)
985 maybe_WNOHANG = WNOHANG;
986 while (1) {
987 pid_t wpid;
988 struct init_action *a;
989
Denys Vlasenko3ed181b2009-07-19 14:29:18 +0200990 /* If signals happen _in_ the wait, they interrupt it,
991 * bb_signals_recursive_norestart set them up that way
992 */
Denis Vlasenko47741792009-03-10 16:01:57 +0000993 wpid = waitpid(-1, NULL, maybe_WNOHANG);
994 if (wpid <= 0)
995 break;
996
997 a = mark_terminated(wpid);
Denis Vlasenko72c99af2009-01-31 01:03:45 +0000998 if (a) {
999 message(L_LOG, "process '%s' (pid %d) exited. "
1000 "Scheduling for restart.",
1001 a->command, wpid);
Erik Andersene49d5ec2000-02-08 19:58:47 +00001002 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001003 /* See if anyone else is waiting to be reaped */
Denis Vlasenko47741792009-03-10 16:01:57 +00001004 maybe_WNOHANG = WNOHANG;
Erik Andersene49d5ec2000-02-08 19:58:47 +00001005 }
Denis Vlasenko72c99af2009-01-31 01:03:45 +00001006 } /* while (1) */
Eric Andersencc8ed391999-10-05 16:24:54 +00001007}