Contents of /trunk/mkinitrd-magellan/busybox/init/init.c
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Sun May 30 11:32:42 2010 UTC (14 years, 4 months ago) by niro
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Sun May 30 11:32:42 2010 UTC (14 years, 4 months ago) by niro
File MIME type: text/plain
File size: 28454 byte(s)
-updated to busybox-1.16.1 and enabled blkid/uuid support in default config
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Mini init implementation for busybox |
4 | * |
5 | * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>. |
6 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
7 | * Adjusted by so many folks, it's impossible to keep track. |
8 | * |
9 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
10 | */ |
11 | |
12 | #include "libbb.h" |
13 | #include <syslog.h> |
14 | #include <paths.h> |
15 | #include <sys/reboot.h> |
16 | #include <sys/resource.h> |
17 | #include <linux/vt.h> |
18 | |
19 | |
20 | /* 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 | |
24 | #define COMMAND_SIZE 256 |
25 | #define CONSOLE_NAME_SIZE 32 |
26 | |
27 | /* Default sysinit script. */ |
28 | #ifndef INIT_SCRIPT |
29 | #define INIT_SCRIPT "/etc/init.d/rcS" |
30 | #endif |
31 | |
32 | /* 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 */ |
36 | #define SYSINIT 0x01 |
37 | /* 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 processed only after |
44 | * each group of actions. If new inittab adds, say, a SYSINIT action, |
45 | * it will not be run, since init is already "past SYSINIT stage". |
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 | */ |
56 | #define CTRLALTDEL 0x20 |
57 | /* |
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 | */ |
63 | #define SHUTDOWN 0x40 |
64 | /* |
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 | */ |
70 | #define RESTART 0x80 |
71 | |
72 | |
73 | /* A linked list of init_actions, to be read from inittab */ |
74 | struct init_action { |
75 | struct init_action *next; |
76 | pid_t pid; |
77 | uint8_t action_type; |
78 | char terminal[CONSOLE_NAME_SIZE]; |
79 | char command[COMMAND_SIZE]; |
80 | }; |
81 | |
82 | static struct init_action *init_action_list = NULL; |
83 | |
84 | static const char *log_console = VC_5; |
85 | |
86 | enum { |
87 | L_LOG = 0x1, |
88 | L_CONSOLE = 0x2, |
89 | #ifndef RB_HALT_SYSTEM |
90 | RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */ |
91 | RB_ENABLE_CAD = 0x89abcdef, |
92 | RB_DISABLE_CAD = 0, |
93 | RB_POWER_OFF = 0x4321fedc, |
94 | RB_AUTOBOOT = 0x01234567, |
95 | #endif |
96 | }; |
97 | |
98 | /* Print a message to the specified device. |
99 | * "where" may be bitwise-or'd from L_LOG | L_CONSOLE |
100 | * NB: careful, we can be called after vfork! |
101 | */ |
102 | #define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0) |
103 | static void message(int where, const char *fmt, ...) |
104 | __attribute__ ((format(printf, 2, 3))); |
105 | static void message(int where, const char *fmt, ...) |
106 | { |
107 | va_list arguments; |
108 | unsigned l; |
109 | char msg[128]; |
110 | |
111 | msg[0] = '\r'; |
112 | va_start(arguments, fmt); |
113 | l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments); |
114 | if (l > sizeof(msg) - 1) |
115 | l = sizeof(msg) - 1; |
116 | va_end(arguments); |
117 | |
118 | #if ENABLE_FEATURE_INIT_SYSLOG |
119 | msg[l] = '\0'; |
120 | if (where & L_LOG) { |
121 | /* Log the message to syslogd */ |
122 | openlog(applet_name, 0, LOG_DAEMON); |
123 | /* don't print "\r" */ |
124 | syslog(LOG_INFO, "%s", msg + 1); |
125 | closelog(); |
126 | } |
127 | msg[l++] = '\n'; |
128 | msg[l] = '\0'; |
129 | #else |
130 | { |
131 | static int log_fd = -1; |
132 | |
133 | msg[l++] = '\n'; |
134 | msg[l] = '\0'; |
135 | /* Take full control of the log tty, and never close it. |
136 | * It's mine, all mine! Muhahahaha! */ |
137 | if (log_fd < 0) { |
138 | if (!log_console) { |
139 | log_fd = STDERR_FILENO; |
140 | } else { |
141 | log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY); |
142 | if (log_fd < 0) { |
143 | bb_error_msg("can't log to %s", log_console); |
144 | where = L_CONSOLE; |
145 | } else { |
146 | close_on_exec_on(log_fd); |
147 | } |
148 | } |
149 | } |
150 | if (where & L_LOG) { |
151 | full_write(log_fd, msg, l); |
152 | if (log_fd == STDERR_FILENO) |
153 | return; /* don't print dup messages */ |
154 | } |
155 | } |
156 | #endif |
157 | |
158 | if (where & L_CONSOLE) { |
159 | /* Send console messages to console so people will see them. */ |
160 | full_write(STDERR_FILENO, msg, l); |
161 | } |
162 | } |
163 | |
164 | static void console_init(void) |
165 | { |
166 | int vtno; |
167 | char *s; |
168 | |
169 | s = getenv("CONSOLE"); |
170 | if (!s) |
171 | s = getenv("console"); |
172 | if (s) { |
173 | int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY); |
174 | if (fd >= 0) { |
175 | dup2(fd, STDIN_FILENO); |
176 | dup2(fd, STDOUT_FILENO); |
177 | xmove_fd(fd, STDERR_FILENO); |
178 | } |
179 | dbg_message(L_LOG, "console='%s'", s); |
180 | } else { |
181 | /* Make sure fd 0,1,2 are not closed |
182 | * (so that they won't be used by future opens) */ |
183 | bb_sanitize_stdio(); |
184 | // Users report problems |
185 | // /* Make sure init can't be blocked by writing to stderr */ |
186 | // fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK); |
187 | } |
188 | |
189 | s = getenv("TERM"); |
190 | if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) { |
191 | /* Not a linux terminal, probably serial console. |
192 | * Force the TERM setting to vt102 |
193 | * if TERM is set to linux (the default) */ |
194 | if (!s || strcmp(s, "linux") == 0) |
195 | putenv((char*)"TERM=vt102"); |
196 | if (!ENABLE_FEATURE_INIT_SYSLOG) |
197 | log_console = NULL; |
198 | } else if (!s) |
199 | putenv((char*)"TERM=linux"); |
200 | } |
201 | |
202 | /* Set terminal settings to reasonable defaults. |
203 | * NB: careful, we can be called after vfork! */ |
204 | static void set_sane_term(void) |
205 | { |
206 | struct termios tty; |
207 | |
208 | tcgetattr(STDIN_FILENO, &tty); |
209 | |
210 | /* set control chars */ |
211 | tty.c_cc[VINTR] = 3; /* C-c */ |
212 | tty.c_cc[VQUIT] = 28; /* C-\ */ |
213 | tty.c_cc[VERASE] = 127; /* C-? */ |
214 | tty.c_cc[VKILL] = 21; /* C-u */ |
215 | tty.c_cc[VEOF] = 4; /* C-d */ |
216 | tty.c_cc[VSTART] = 17; /* C-q */ |
217 | tty.c_cc[VSTOP] = 19; /* C-s */ |
218 | tty.c_cc[VSUSP] = 26; /* C-z */ |
219 | |
220 | /* use line discipline 0 */ |
221 | tty.c_line = 0; |
222 | |
223 | /* Make it be sane */ |
224 | tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD; |
225 | tty.c_cflag |= CREAD | HUPCL | CLOCAL; |
226 | |
227 | /* input modes */ |
228 | tty.c_iflag = ICRNL | IXON | IXOFF; |
229 | |
230 | /* output modes */ |
231 | tty.c_oflag = OPOST | ONLCR; |
232 | |
233 | /* local modes */ |
234 | tty.c_lflag = |
235 | ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN; |
236 | |
237 | tcsetattr_stdin_TCSANOW(&tty); |
238 | } |
239 | |
240 | /* Open the new terminal device. |
241 | * NB: careful, we can be called after vfork! */ |
242 | static int open_stdio_to_tty(const char* tty_name) |
243 | { |
244 | /* empty tty_name means "use init's tty", else... */ |
245 | if (tty_name[0]) { |
246 | int fd; |
247 | |
248 | close(STDIN_FILENO); |
249 | /* fd can be only < 0 or 0: */ |
250 | fd = device_open(tty_name, O_RDWR); |
251 | if (fd) { |
252 | message(L_LOG | L_CONSOLE, "can't open %s: %s", |
253 | tty_name, strerror(errno)); |
254 | return 0; /* failure */ |
255 | } |
256 | dup2(STDIN_FILENO, STDOUT_FILENO); |
257 | dup2(STDIN_FILENO, STDERR_FILENO); |
258 | } |
259 | set_sane_term(); |
260 | return 1; /* success */ |
261 | } |
262 | |
263 | static void reset_sighandlers_and_unblock_sigs(void) |
264 | { |
265 | bb_signals(0 |
266 | + (1 << SIGUSR1) |
267 | + (1 << SIGUSR2) |
268 | + (1 << SIGTERM) |
269 | + (1 << SIGQUIT) |
270 | + (1 << SIGINT) |
271 | + (1 << SIGHUP) |
272 | + (1 << SIGTSTP) |
273 | + (1 << SIGSTOP) |
274 | , SIG_DFL); |
275 | sigprocmask_allsigs(SIG_UNBLOCK); |
276 | } |
277 | |
278 | /* Wrapper around exec: |
279 | * Takes string (max COMMAND_SIZE chars). |
280 | * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'. |
281 | * Otherwise splits words on whitespace, deals with leading dash, |
282 | * and uses plain exec(). |
283 | * NB: careful, we can be called after vfork! |
284 | */ |
285 | static void init_exec(const char *command) |
286 | { |
287 | char *cmd[COMMAND_SIZE / 2]; |
288 | char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */ |
289 | int dash = (command[0] == '-' /* maybe? && command[1] == '/' */); |
290 | |
291 | /* See if any special /bin/sh requiring characters are present */ |
292 | if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) { |
293 | strcpy(buf, "exec "); |
294 | strcpy(buf + 5, command + dash); /* excluding "-" */ |
295 | /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */ |
296 | cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash); |
297 | cmd[1] = (char*)"-c"; |
298 | cmd[2] = buf; |
299 | cmd[3] = NULL; |
300 | } else { |
301 | /* Convert command (char*) into cmd (char**, one word per string) */ |
302 | char *word, *next; |
303 | int i = 0; |
304 | next = strcpy(buf, command); /* including "-" */ |
305 | while ((word = strsep(&next, " \t")) != NULL) { |
306 | if (*word != '\0') { /* not two spaces/tabs together? */ |
307 | cmd[i] = word; |
308 | i++; |
309 | } |
310 | } |
311 | cmd[i] = NULL; |
312 | } |
313 | /* If we saw leading "-", it is interactive shell. |
314 | * Try harder to give it a controlling tty. |
315 | * And skip "-" in actual exec call. */ |
316 | if (dash) { |
317 | /* _Attempt_ to make stdin a controlling tty. */ |
318 | if (ENABLE_FEATURE_INIT_SCTTY) |
319 | ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/); |
320 | } |
321 | BB_EXECVP(cmd[0] + dash, cmd); |
322 | message(L_LOG | L_CONSOLE, "can't run '%s': %s", cmd[0], strerror(errno)); |
323 | /* returns if execvp fails */ |
324 | } |
325 | |
326 | /* Used only by run_actions */ |
327 | static pid_t run(const struct init_action *a) |
328 | { |
329 | pid_t pid; |
330 | |
331 | /* Careful: don't be affected by a signal in vforked child */ |
332 | sigprocmask_allsigs(SIG_BLOCK); |
333 | if (BB_MMU && (a->action_type & ASKFIRST)) |
334 | pid = fork(); |
335 | else |
336 | pid = vfork(); |
337 | if (pid < 0) |
338 | message(L_LOG | L_CONSOLE, "can't fork"); |
339 | if (pid) { |
340 | sigprocmask_allsigs(SIG_UNBLOCK); |
341 | return pid; /* Parent or error */ |
342 | } |
343 | |
344 | /* Child */ |
345 | |
346 | /* Reset signal handlers that were set by the parent process */ |
347 | reset_sighandlers_and_unblock_sigs(); |
348 | |
349 | /* Create a new session and make ourself the process group leader */ |
350 | setsid(); |
351 | |
352 | /* Open the new terminal device */ |
353 | if (!open_stdio_to_tty(a->terminal)) |
354 | _exit(EXIT_FAILURE); |
355 | |
356 | /* NB: on NOMMU we can't wait for input in child, so |
357 | * "askfirst" will work the same as "respawn". */ |
358 | if (BB_MMU && (a->action_type & ASKFIRST)) { |
359 | static const char press_enter[] ALIGN1 = |
360 | #ifdef CUSTOMIZED_BANNER |
361 | #include CUSTOMIZED_BANNER |
362 | #endif |
363 | "\nPlease press Enter to activate this console. "; |
364 | char c; |
365 | /* |
366 | * Save memory by not exec-ing anything large (like a shell) |
367 | * before the user wants it. This is critical if swap is not |
368 | * enabled and the system has low memory. Generally this will |
369 | * be run on the second virtual console, and the first will |
370 | * be allowed to start a shell or whatever an init script |
371 | * specifies. |
372 | */ |
373 | dbg_message(L_LOG, "waiting for enter to start '%s'" |
374 | "(pid %d, tty '%s')\n", |
375 | a->command, getpid(), a->terminal); |
376 | full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1); |
377 | while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n') |
378 | continue; |
379 | } |
380 | |
381 | /* |
382 | * When a file named /.init_enable_core exists, setrlimit is called |
383 | * before processes are spawned to set core file size as unlimited. |
384 | * This is for debugging only. Don't use this is production, unless |
385 | * you want core dumps lying about.... |
386 | */ |
387 | if (ENABLE_FEATURE_INIT_COREDUMPS) { |
388 | if (access("/.init_enable_core", F_OK) == 0) { |
389 | struct rlimit limit; |
390 | limit.rlim_cur = RLIM_INFINITY; |
391 | limit.rlim_max = RLIM_INFINITY; |
392 | setrlimit(RLIMIT_CORE, &limit); |
393 | } |
394 | } |
395 | |
396 | /* Log the process name and args */ |
397 | message(L_LOG, "starting pid %d, tty '%s': '%s'", |
398 | getpid(), a->terminal, a->command); |
399 | |
400 | /* Now run it. The new program will take over this PID, |
401 | * so nothing further in init.c should be run. */ |
402 | init_exec(a->command); |
403 | /* We're still here? Some error happened. */ |
404 | _exit(-1); |
405 | } |
406 | |
407 | static struct init_action *mark_terminated(pid_t pid) |
408 | { |
409 | struct init_action *a; |
410 | |
411 | if (pid > 0) { |
412 | for (a = init_action_list; a; a = a->next) { |
413 | if (a->pid == pid) { |
414 | a->pid = 0; |
415 | return a; |
416 | } |
417 | } |
418 | } |
419 | return NULL; |
420 | } |
421 | |
422 | static void waitfor(pid_t pid) |
423 | { |
424 | /* waitfor(run(x)): protect against failed fork inside run() */ |
425 | if (pid <= 0) |
426 | return; |
427 | |
428 | /* Wait for any child (prevent zombies from exiting orphaned processes) |
429 | * but exit the loop only when specified one has exited. */ |
430 | while (1) { |
431 | pid_t wpid = wait(NULL); |
432 | mark_terminated(wpid); |
433 | /* Unsafe. SIGTSTP handler might have wait'ed it already */ |
434 | /*if (wpid == pid) break;*/ |
435 | /* More reliable: */ |
436 | if (kill(pid, 0)) |
437 | break; |
438 | } |
439 | } |
440 | |
441 | /* Run all commands of a particular type */ |
442 | static void run_actions(int action_type) |
443 | { |
444 | struct init_action *a; |
445 | |
446 | for (a = init_action_list; a; a = a->next) { |
447 | if (!(a->action_type & action_type)) |
448 | continue; |
449 | |
450 | if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) { |
451 | pid_t pid = run(a); |
452 | if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN)) |
453 | waitfor(pid); |
454 | } |
455 | if (a->action_type & (RESPAWN | ASKFIRST)) { |
456 | /* Only run stuff with pid == 0. If pid != 0, |
457 | * it is already running |
458 | */ |
459 | if (a->pid == 0) |
460 | a->pid = run(a); |
461 | } |
462 | } |
463 | } |
464 | |
465 | static void new_init_action(uint8_t action_type, const char *command, const char *cons) |
466 | { |
467 | struct init_action *a, **nextp; |
468 | |
469 | /* Scenario: |
470 | * old inittab: |
471 | * ::shutdown:umount -a -r |
472 | * ::shutdown:swapoff -a |
473 | * new inittab: |
474 | * ::shutdown:swapoff -a |
475 | * ::shutdown:umount -a -r |
476 | * On reload, we must ensure entries end up in correct order. |
477 | * To achieve that, if we find a matching entry, we move it |
478 | * to the end. |
479 | */ |
480 | nextp = &init_action_list; |
481 | while ((a = *nextp) != NULL) { |
482 | /* Don't enter action if it's already in the list, |
483 | * This prevents losing running RESPAWNs. |
484 | */ |
485 | if (strcmp(a->command, command) == 0 |
486 | && strcmp(a->terminal, cons) == 0 |
487 | ) { |
488 | /* Remove from list */ |
489 | *nextp = a->next; |
490 | /* Find the end of the list */ |
491 | while (*nextp != NULL) |
492 | nextp = &(*nextp)->next; |
493 | a->next = NULL; |
494 | break; |
495 | } |
496 | nextp = &a->next; |
497 | } |
498 | |
499 | if (!a) |
500 | a = xzalloc(sizeof(*a)); |
501 | /* Append to the end of the list */ |
502 | *nextp = a; |
503 | a->action_type = action_type; |
504 | safe_strncpy(a->command, command, sizeof(a->command)); |
505 | safe_strncpy(a->terminal, cons, sizeof(a->terminal)); |
506 | dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n", |
507 | a->command, a->action_type, a->terminal); |
508 | } |
509 | |
510 | /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined, |
511 | * then parse_inittab() simply adds in some default |
512 | * actions(i.e., runs INIT_SCRIPT and then starts a pair |
513 | * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB |
514 | * _is_ defined, but /etc/inittab is missing, this |
515 | * results in the same set of default behaviors. |
516 | */ |
517 | static void parse_inittab(void) |
518 | { |
519 | #if ENABLE_FEATURE_USE_INITTAB |
520 | char *token[4]; |
521 | parser_t *parser = config_open2("/etc/inittab", fopen_for_read); |
522 | |
523 | if (parser == NULL) |
524 | #endif |
525 | { |
526 | /* No inittab file - set up some default behavior */ |
527 | /* Reboot on Ctrl-Alt-Del */ |
528 | new_init_action(CTRLALTDEL, "reboot", ""); |
529 | /* Umount all filesystems on halt/reboot */ |
530 | new_init_action(SHUTDOWN, "umount -a -r", ""); |
531 | /* Swapoff on halt/reboot */ |
532 | if (ENABLE_SWAPONOFF) |
533 | new_init_action(SHUTDOWN, "swapoff -a", ""); |
534 | /* Prepare to restart init when a QUIT is received */ |
535 | new_init_action(RESTART, "init", ""); |
536 | /* Askfirst shell on tty1-4 */ |
537 | new_init_action(ASKFIRST, bb_default_login_shell, ""); |
538 | //TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users |
539 | new_init_action(ASKFIRST, bb_default_login_shell, VC_2); |
540 | new_init_action(ASKFIRST, bb_default_login_shell, VC_3); |
541 | new_init_action(ASKFIRST, bb_default_login_shell, VC_4); |
542 | /* sysinit */ |
543 | new_init_action(SYSINIT, INIT_SCRIPT, ""); |
544 | return; |
545 | } |
546 | |
547 | #if ENABLE_FEATURE_USE_INITTAB |
548 | /* optional_tty:ignored_runlevel:action:command |
549 | * Delims are not to be collapsed and need exactly 4 tokens |
550 | */ |
551 | while (config_read(parser, token, 4, 0, "#:", |
552 | PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) { |
553 | /* order must correspond to SYSINIT..RESTART constants */ |
554 | static const char actions[] ALIGN1 = |
555 | "sysinit\0""wait\0""once\0""respawn\0""askfirst\0" |
556 | "ctrlaltdel\0""shutdown\0""restart\0"; |
557 | int action; |
558 | char *tty = token[0]; |
559 | |
560 | if (!token[3]) /* less than 4 tokens */ |
561 | goto bad_entry; |
562 | action = index_in_strings(actions, token[2]); |
563 | if (action < 0 || !token[3][0]) /* token[3]: command */ |
564 | goto bad_entry; |
565 | /* turn .*TTY -> /dev/TTY */ |
566 | if (tty[0]) { |
567 | if (strncmp(tty, "/dev/", 5) == 0) |
568 | tty += 5; |
569 | tty = concat_path_file("/dev/", tty); |
570 | } |
571 | new_init_action(1 << action, token[3], tty); |
572 | if (tty[0]) |
573 | free(tty); |
574 | continue; |
575 | bad_entry: |
576 | message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d", |
577 | parser->lineno); |
578 | } |
579 | config_close(parser); |
580 | #endif |
581 | } |
582 | |
583 | static void pause_and_low_level_reboot(unsigned magic) NORETURN; |
584 | static void pause_and_low_level_reboot(unsigned magic) |
585 | { |
586 | pid_t pid; |
587 | |
588 | /* Allow time for last message to reach serial console, etc */ |
589 | sleep(1); |
590 | |
591 | /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS) |
592 | * in linux/kernel/sys.c, which can cause the machine to panic when |
593 | * the init process exits... */ |
594 | pid = vfork(); |
595 | if (pid == 0) { /* child */ |
596 | reboot(magic); |
597 | _exit(EXIT_SUCCESS); |
598 | } |
599 | while (1) |
600 | sleep(1); |
601 | } |
602 | |
603 | static void run_shutdown_and_kill_processes(void) |
604 | { |
605 | /* Run everything to be run at "shutdown". This is done _prior_ |
606 | * to killing everything, in case people wish to use scripts to |
607 | * shut things down gracefully... */ |
608 | run_actions(SHUTDOWN); |
609 | |
610 | message(L_CONSOLE | L_LOG, "The system is going down NOW!"); |
611 | |
612 | /* Send signals to every process _except_ pid 1 */ |
613 | kill(-1, SIGTERM); |
614 | message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM"); |
615 | sync(); |
616 | sleep(1); |
617 | |
618 | kill(-1, SIGKILL); |
619 | message(L_CONSOLE, "Sent SIG%s to all processes", "KILL"); |
620 | sync(); |
621 | /*sleep(1); - callers take care about making a pause */ |
622 | } |
623 | |
624 | /* Signal handling by init: |
625 | * |
626 | * For process with PID==1, on entry kernel sets all signals to SIG_DFL |
627 | * and unmasks all signals. However, for process with PID==1, |
628 | * default action (SIG_DFL) on any signal is to ignore it, |
629 | * even for special signals SIGKILL and SIGCONT. |
630 | * Also, any signal can be caught or blocked. |
631 | * (but SIGSTOP is still handled specially, at least in 2.6.20) |
632 | * |
633 | * We install two kinds of handlers, "immediate" and "delayed". |
634 | * |
635 | * Immediate handlers execute at any time, even while, say, sysinit |
636 | * is running. |
637 | * |
638 | * Delayed handlers just set a flag variable. The variable is checked |
639 | * in the main loop and acted upon. |
640 | * |
641 | * halt/poweroff/reboot and restart have immediate handlers. |
642 | * They only traverse linked list of struct action's, never modify it, |
643 | * this should be safe to do even in signal handler. Also they |
644 | * never return. |
645 | * |
646 | * SIGSTOP and SIGTSTP have immediate handlers. They just wait |
647 | * for SIGCONT to happen. |
648 | * |
649 | * SIGHUP has a delayed handler, because modifying linked list |
650 | * of struct action's from a signal handler while it is manipulated |
651 | * by the program may be disastrous. |
652 | * |
653 | * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing |
654 | * it to happen even somewhere inside "sysinit" would be a bit awkward. |
655 | * |
656 | * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide |
657 | * and only one will be remembered and acted upon. |
658 | */ |
659 | |
660 | /* The SIGUSR[12]/SIGTERM handler */ |
661 | static void halt_reboot_pwoff(int sig) NORETURN; |
662 | static void halt_reboot_pwoff(int sig) |
663 | { |
664 | const char *m; |
665 | unsigned rb; |
666 | |
667 | /* We may call run() and it unmasks signals, |
668 | * including the one masked inside this signal handler. |
669 | * Testcase which would start multiple reboot scripts: |
670 | * while true; do reboot; done |
671 | * Preventing it: |
672 | */ |
673 | reset_sighandlers_and_unblock_sigs(); |
674 | |
675 | run_shutdown_and_kill_processes(); |
676 | |
677 | m = "halt"; |
678 | rb = RB_HALT_SYSTEM; |
679 | if (sig == SIGTERM) { |
680 | m = "reboot"; |
681 | rb = RB_AUTOBOOT; |
682 | } else if (sig == SIGUSR2) { |
683 | m = "poweroff"; |
684 | rb = RB_POWER_OFF; |
685 | } |
686 | message(L_CONSOLE, "Requesting system %s", m); |
687 | pause_and_low_level_reboot(rb); |
688 | /* not reached */ |
689 | } |
690 | |
691 | /* Handler for QUIT - exec "restart" action, |
692 | * else (no such action defined) do nothing */ |
693 | static void restart_handler(int sig UNUSED_PARAM) |
694 | { |
695 | struct init_action *a; |
696 | |
697 | for (a = init_action_list; a; a = a->next) { |
698 | if (!(a->action_type & RESTART)) |
699 | continue; |
700 | |
701 | /* Starting from here, we won't return. |
702 | * Thus don't need to worry about preserving errno |
703 | * and such. |
704 | */ |
705 | |
706 | reset_sighandlers_and_unblock_sigs(); |
707 | |
708 | run_shutdown_and_kill_processes(); |
709 | |
710 | /* Allow Ctrl-Alt-Del to reboot the system. |
711 | * This is how kernel sets it up for init, we follow suit. |
712 | */ |
713 | reboot(RB_ENABLE_CAD); /* misnomer */ |
714 | |
715 | if (open_stdio_to_tty(a->terminal)) { |
716 | dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command); |
717 | /* Theoretically should be safe. |
718 | * But in practice, kernel bugs may leave |
719 | * unkillable processes, and wait() may block forever. |
720 | * Oh well. Hoping "new" init won't be too surprised |
721 | * by having children it didn't create. |
722 | */ |
723 | //while (wait(NULL) > 0) |
724 | // continue; |
725 | init_exec(a->command); |
726 | } |
727 | /* Open or exec failed */ |
728 | pause_and_low_level_reboot(RB_HALT_SYSTEM); |
729 | /* not reached */ |
730 | } |
731 | } |
732 | |
733 | /* The SIGSTOP/SIGTSTP handler |
734 | * NB: inside it, all signals except SIGCONT are masked |
735 | * via appropriate setup in sigaction(). |
736 | */ |
737 | static void stop_handler(int sig UNUSED_PARAM) |
738 | { |
739 | smallint saved_bb_got_signal; |
740 | int saved_errno; |
741 | |
742 | saved_bb_got_signal = bb_got_signal; |
743 | saved_errno = errno; |
744 | signal(SIGCONT, record_signo); |
745 | |
746 | while (1) { |
747 | pid_t wpid; |
748 | |
749 | if (bb_got_signal == SIGCONT) |
750 | break; |
751 | /* NB: this can accidentally wait() for a process |
752 | * which we waitfor() elsewhere! waitfor() must have |
753 | * code which is resilient against this. |
754 | */ |
755 | wpid = wait_any_nohang(NULL); |
756 | mark_terminated(wpid); |
757 | sleep(1); |
758 | } |
759 | |
760 | signal(SIGCONT, SIG_DFL); |
761 | errno = saved_errno; |
762 | bb_got_signal = saved_bb_got_signal; |
763 | } |
764 | |
765 | #if ENABLE_FEATURE_USE_INITTAB |
766 | static void reload_inittab(void) |
767 | { |
768 | struct init_action *a, **nextp; |
769 | |
770 | message(L_LOG, "reloading /etc/inittab"); |
771 | |
772 | /* Disable old entries */ |
773 | for (a = init_action_list; a; a = a->next) |
774 | a->action_type = 0; |
775 | |
776 | /* Append new entries, or modify existing entries |
777 | * (incl. setting a->action_type) if cmd and device name |
778 | * match new ones. End result: only entries with |
779 | * a->action_type == 0 are stale. |
780 | */ |
781 | parse_inittab(); |
782 | |
783 | #if ENABLE_FEATURE_KILL_REMOVED |
784 | /* Kill stale entries */ |
785 | /* Be nice and send SIGTERM first */ |
786 | for (a = init_action_list; a; a = a->next) |
787 | if (a->action_type == 0 && a->pid != 0) |
788 | kill(a->pid, SIGTERM); |
789 | if (CONFIG_FEATURE_KILL_DELAY) { |
790 | /* NB: parent will wait in NOMMU case */ |
791 | if ((BB_MMU ? fork() : vfork()) == 0) { /* child */ |
792 | sleep(CONFIG_FEATURE_KILL_DELAY); |
793 | for (a = init_action_list; a; a = a->next) |
794 | if (a->action_type == 0 && a->pid != 0) |
795 | kill(a->pid, SIGKILL); |
796 | _exit(EXIT_SUCCESS); |
797 | } |
798 | } |
799 | #endif |
800 | |
801 | /* Remove stale entries and SYSINIT entries. |
802 | * We never rerun SYSINIT entries anyway, |
803 | * removing them too saves a few bytes */ |
804 | nextp = &init_action_list; |
805 | while ((a = *nextp) != NULL) { |
806 | if ((a->action_type & ~SYSINIT) == 0) { |
807 | *nextp = a->next; |
808 | free(a); |
809 | } else { |
810 | nextp = &a->next; |
811 | } |
812 | } |
813 | |
814 | /* Not needed: */ |
815 | /* run_actions(RESPAWN | ASKFIRST); */ |
816 | /* - we return to main loop, which does this automagically */ |
817 | } |
818 | #endif |
819 | |
820 | static int check_delayed_sigs(void) |
821 | { |
822 | int sigs_seen = 0; |
823 | |
824 | while (1) { |
825 | smallint sig = bb_got_signal; |
826 | |
827 | if (!sig) |
828 | return sigs_seen; |
829 | bb_got_signal = 0; |
830 | sigs_seen = 1; |
831 | #if ENABLE_FEATURE_USE_INITTAB |
832 | if (sig == SIGHUP) |
833 | reload_inittab(); |
834 | #endif |
835 | if (sig == SIGINT) |
836 | run_actions(CTRLALTDEL); |
837 | } |
838 | } |
839 | |
840 | int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
841 | int init_main(int argc UNUSED_PARAM, char **argv) |
842 | { |
843 | die_sleep = 30 * 24*60*60; /* if xmalloc would ever die... */ |
844 | |
845 | if (argv[1] && strcmp(argv[1], "-q") == 0) { |
846 | return kill(1, SIGHUP); |
847 | } |
848 | |
849 | if (!DEBUG_INIT) { |
850 | /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */ |
851 | if (getpid() != 1 |
852 | && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc")) |
853 | ) { |
854 | bb_show_usage(); |
855 | } |
856 | /* Turn off rebooting via CTL-ALT-DEL - we get a |
857 | * SIGINT on CAD so we can shut things down gracefully... */ |
858 | reboot(RB_DISABLE_CAD); /* misnomer */ |
859 | } |
860 | |
861 | /* Figure out where the default console should be */ |
862 | console_init(); |
863 | set_sane_term(); |
864 | xchdir("/"); |
865 | setsid(); |
866 | |
867 | /* Make sure environs is set to something sane */ |
868 | putenv((char *) "HOME=/"); |
869 | putenv((char *) bb_PATH_root_path); |
870 | putenv((char *) "SHELL=/bin/sh"); |
871 | putenv((char *) "USER=root"); /* needed? why? */ |
872 | |
873 | if (argv[1]) |
874 | xsetenv("RUNLEVEL", argv[1]); |
875 | |
876 | #if !ENABLE_FEATURE_EXTRA_QUIET |
877 | /* Hello world */ |
878 | message(L_CONSOLE | L_LOG, "init started: %s", bb_banner); |
879 | #endif |
880 | |
881 | /* Make sure there is enough memory to do something useful. */ |
882 | if (ENABLE_SWAPONOFF) { |
883 | struct sysinfo info; |
884 | |
885 | if (sysinfo(&info) == 0 |
886 | && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024 |
887 | ) { |
888 | message(L_CONSOLE, "Low memory, forcing swapon"); |
889 | /* swapon -a requires /proc typically */ |
890 | new_init_action(SYSINIT, "mount -t proc proc /proc", ""); |
891 | /* Try to turn on swap */ |
892 | new_init_action(SYSINIT, "swapon -a", ""); |
893 | run_actions(SYSINIT); /* wait and removing */ |
894 | } |
895 | } |
896 | |
897 | /* Check if we are supposed to be in single user mode */ |
898 | if (argv[1] |
899 | && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1')) |
900 | ) { |
901 | /* ??? shouldn't we set RUNLEVEL="b" here? */ |
902 | /* Start a shell on console */ |
903 | new_init_action(RESPAWN, bb_default_login_shell, ""); |
904 | } else { |
905 | /* Not in single user mode - see what inittab says */ |
906 | |
907 | /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined, |
908 | * then parse_inittab() simply adds in some default |
909 | * actions(i.e., INIT_SCRIPT and a pair |
910 | * of "askfirst" shells */ |
911 | parse_inittab(); |
912 | } |
913 | |
914 | #if ENABLE_SELINUX |
915 | if (getenv("SELINUX_INIT") == NULL) { |
916 | int enforce = 0; |
917 | |
918 | putenv((char*)"SELINUX_INIT=YES"); |
919 | if (selinux_init_load_policy(&enforce) == 0) { |
920 | BB_EXECVP(argv[0], argv); |
921 | } else if (enforce > 0) { |
922 | /* SELinux in enforcing mode but load_policy failed */ |
923 | message(L_CONSOLE, "can't load SELinux Policy. " |
924 | "Machine is in enforcing mode. Halting now."); |
925 | exit(EXIT_FAILURE); |
926 | } |
927 | } |
928 | #endif |
929 | |
930 | /* Make the command line just say "init" - thats all, nothing else */ |
931 | strncpy(argv[0], "init", strlen(argv[0])); |
932 | /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */ |
933 | while (*++argv) |
934 | memset(*argv, 0, strlen(*argv)); |
935 | |
936 | /* Set up signal handlers */ |
937 | if (!DEBUG_INIT) { |
938 | struct sigaction sa; |
939 | |
940 | bb_signals(0 |
941 | + (1 << SIGUSR1) /* halt */ |
942 | + (1 << SIGTERM) /* reboot */ |
943 | + (1 << SIGUSR2) /* poweroff */ |
944 | , halt_reboot_pwoff); |
945 | signal(SIGQUIT, restart_handler); /* re-exec another init */ |
946 | |
947 | /* Stop handler must allow only SIGCONT inside itself */ |
948 | memset(&sa, 0, sizeof(sa)); |
949 | sigfillset(&sa.sa_mask); |
950 | sigdelset(&sa.sa_mask, SIGCONT); |
951 | sa.sa_handler = stop_handler; |
952 | /* NB: sa_flags doesn't have SA_RESTART. |
953 | * It must be able to interrupt wait(). |
954 | */ |
955 | sigaction_set(SIGTSTP, &sa); /* pause */ |
956 | /* Does not work as intended, at least in 2.6.20. |
957 | * SIGSTOP is simply ignored by init: |
958 | */ |
959 | sigaction_set(SIGSTOP, &sa); /* pause */ |
960 | |
961 | /* SIGINT (Ctrl-Alt-Del) must interrupt wait(), |
962 | * setting handler without SA_RESTART flag. |
963 | */ |
964 | bb_signals_recursive_norestart((1 << SIGINT), record_signo); |
965 | } |
966 | |
967 | /* Set up "reread /etc/inittab" handler. |
968 | * Handler is set up without SA_RESTART, it will interrupt syscalls. |
969 | */ |
970 | if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB) |
971 | bb_signals_recursive_norestart((1 << SIGHUP), record_signo); |
972 | |
973 | /* Now run everything that needs to be run */ |
974 | /* First run the sysinit command */ |
975 | run_actions(SYSINIT); |
976 | check_delayed_sigs(); |
977 | /* Next run anything that wants to block */ |
978 | run_actions(WAIT); |
979 | check_delayed_sigs(); |
980 | /* Next run anything to be run only once */ |
981 | run_actions(ONCE); |
982 | |
983 | /* Now run the looping stuff for the rest of forever. |
984 | */ |
985 | while (1) { |
986 | int maybe_WNOHANG; |
987 | |
988 | maybe_WNOHANG = check_delayed_sigs(); |
989 | |
990 | /* (Re)run the respawn/askfirst stuff */ |
991 | run_actions(RESPAWN | ASKFIRST); |
992 | maybe_WNOHANG |= check_delayed_sigs(); |
993 | |
994 | /* Don't consume all CPU time - sleep a bit */ |
995 | sleep(1); |
996 | maybe_WNOHANG |= check_delayed_sigs(); |
997 | |
998 | /* Wait for any child process(es) to exit. |
999 | * |
1000 | * If check_delayed_sigs above reported that a signal |
1001 | * was caught, wait will be nonblocking. This ensures |
1002 | * that if SIGHUP has reloaded inittab, respawn and askfirst |
1003 | * actions will not be delayed until next child death. |
1004 | */ |
1005 | if (maybe_WNOHANG) |
1006 | maybe_WNOHANG = WNOHANG; |
1007 | while (1) { |
1008 | pid_t wpid; |
1009 | struct init_action *a; |
1010 | |
1011 | /* If signals happen _in_ the wait, they interrupt it, |
1012 | * bb_signals_recursive_norestart set them up that way |
1013 | */ |
1014 | wpid = waitpid(-1, NULL, maybe_WNOHANG); |
1015 | if (wpid <= 0) |
1016 | break; |
1017 | |
1018 | a = mark_terminated(wpid); |
1019 | if (a) { |
1020 | message(L_LOG, "process '%s' (pid %d) exited. " |
1021 | "Scheduling for restart.", |
1022 | a->command, wpid); |
1023 | } |
1024 | /* See if anyone else is waiting to be reaped */ |
1025 | maybe_WNOHANG = WNOHANG; |
1026 | } |
1027 | } /* while (1) */ |
1028 | } |