Annotation of /trunk/mkinitrd-magellan/busybox/init/init.c
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Revision 984 -
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Sun May 30 11:32:42 2010 UTC (14 years ago) by niro
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File size: 28454 byte(s)
Sun May 30 11:32:42 2010 UTC (14 years 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 | niro | 532 | /* 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 | niro | 816 | #include "libbb.h" |
13 | #include <syslog.h> | ||
14 | niro | 532 | #include <paths.h> |
15 | #include <sys/reboot.h> | ||
16 | niro | 984 | #include <sys/resource.h> |
17 | #include <linux/vt.h> | ||
18 | niro | 532 | |
19 | niro | 984 | |
20 | niro | 816 | /* 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 | niro | 532 | |
24 | niro | 984 | #define COMMAND_SIZE 256 |
25 | niro | 816 | #define CONSOLE_NAME_SIZE 32 |
26 | niro | 532 | |
27 | niro | 984 | /* Default sysinit script. */ |
28 | niro | 532 | #ifndef INIT_SCRIPT |
29 | niro | 984 | #define INIT_SCRIPT "/etc/init.d/rcS" |
30 | niro | 532 | #endif |
31 | |||
32 | niro | 984 | /* 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 | niro | 816 | #define SYSINIT 0x01 |
37 | niro | 984 | /* 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 | niro | 816 | #define CTRLALTDEL 0x20 |
57 | niro | 984 | /* |
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 | niro | 816 | #define SHUTDOWN 0x40 |
64 | niro | 984 | /* |
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 | niro | 816 | #define RESTART 0x80 |
71 | niro | 532 | |
72 | niro | 984 | |
73 | /* A linked list of init_actions, to be read from inittab */ | ||
74 | niro | 532 | struct init_action { |
75 | niro | 816 | struct init_action *next; |
76 | niro | 532 | pid_t pid; |
77 | niro | 816 | uint8_t action_type; |
78 | char terminal[CONSOLE_NAME_SIZE]; | ||
79 | char command[COMMAND_SIZE]; | ||
80 | niro | 532 | }; |
81 | |||
82 | static struct init_action *init_action_list = NULL; | ||
83 | |||
84 | niro | 816 | static const char *log_console = VC_5; |
85 | niro | 532 | |
86 | enum { | ||
87 | niro | 816 | L_LOG = 0x1, |
88 | L_CONSOLE = 0x2, | ||
89 | niro | 532 | #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 | niro | 816 | * "where" may be bitwise-or'd from L_LOG | L_CONSOLE |
100 | * NB: careful, we can be called after vfork! | ||
101 | */ | ||
102 | niro | 984 | #define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0) |
103 | niro | 816 | static void message(int where, const char *fmt, ...) |
104 | niro | 532 | __attribute__ ((format(printf, 2, 3))); |
105 | niro | 816 | static void message(int where, const char *fmt, ...) |
106 | niro | 532 | { |
107 | va_list arguments; | ||
108 | niro | 816 | unsigned l; |
109 | char msg[128]; | ||
110 | niro | 532 | |
111 | msg[0] = '\r'; | ||
112 | niro | 816 | 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 | niro | 532 | |
118 | niro | 984 | #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 | niro | 816 | 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 | niro | 532 | } |
156 | niro | 984 | #endif |
157 | niro | 532 | |
158 | niro | 816 | if (where & L_CONSOLE) { |
159 | /* Send console messages to console so people will see them. */ | ||
160 | full_write(STDERR_FILENO, msg, l); | ||
161 | niro | 532 | } |
162 | niro | 816 | } |
163 | niro | 532 | |
164 | niro | 816 | static void console_init(void) |
165 | { | ||
166 | niro | 984 | int vtno; |
167 | niro | 816 | 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 | niro | 532 | if (fd >= 0) { |
175 | niro | 816 | dup2(fd, STDIN_FILENO); |
176 | dup2(fd, STDOUT_FILENO); | ||
177 | xmove_fd(fd, STDERR_FILENO); | ||
178 | niro | 532 | } |
179 | niro | 984 | dbg_message(L_LOG, "console='%s'", s); |
180 | niro | 816 | } 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 | niro | 532 | } |
188 | niro | 816 | |
189 | s = getenv("TERM"); | ||
190 | niro | 984 | if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) { |
191 | /* Not a linux terminal, probably serial console. | ||
192 | * Force the TERM setting to vt102 | ||
193 | niro | 816 | * 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 | niro | 532 | } |
201 | |||
202 | niro | 816 | /* Set terminal settings to reasonable defaults. |
203 | * NB: careful, we can be called after vfork! */ | ||
204 | static void set_sane_term(void) | ||
205 | niro | 532 | { |
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 | niro | 816 | /* use line discipline 0 */ |
221 | niro | 532 | 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 | niro | 816 | tcsetattr_stdin_TCSANOW(&tty); |
238 | niro | 532 | } |
239 | |||
240 | niro | 816 | /* Open the new terminal device. |
241 | * NB: careful, we can be called after vfork! */ | ||
242 | niro | 984 | static int open_stdio_to_tty(const char* tty_name) |
243 | niro | 532 | { |
244 | niro | 816 | /* empty tty_name means "use init's tty", else... */ |
245 | if (tty_name[0]) { | ||
246 | int fd; | ||
247 | niro | 984 | |
248 | niro | 816 | 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 | niro | 984 | return 0; /* failure */ |
255 | niro | 532 | } |
256 | niro | 816 | dup2(STDIN_FILENO, STDOUT_FILENO); |
257 | dup2(STDIN_FILENO, STDERR_FILENO); | ||
258 | niro | 532 | } |
259 | niro | 816 | set_sane_term(); |
260 | niro | 984 | return 1; /* success */ |
261 | niro | 532 | } |
262 | |||
263 | niro | 984 | 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 | niro | 816 | /* 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 | niro | 532 | { |
287 | niro | 816 | 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 | niro | 532 | |
291 | niro | 816 | /* 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 | niro | 532 | } |
311 | niro | 816 | cmd[i] = NULL; |
312 | niro | 532 | } |
313 | niro | 816 | /* 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 | niro | 984 | message(L_LOG | L_CONSOLE, "can't run '%s': %s", cmd[0], strerror(errno)); |
323 | niro | 816 | /* returns if execvp fails */ |
324 | niro | 532 | } |
325 | |||
326 | niro | 816 | /* Used only by run_actions */ |
327 | niro | 532 | static pid_t run(const struct init_action *a) |
328 | { | ||
329 | pid_t pid; | ||
330 | |||
331 | niro | 984 | /* Careful: don't be affected by a signal in vforked child */ |
332 | sigprocmask_allsigs(SIG_BLOCK); | ||
333 | niro | 816 | 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 | niro | 984 | if (pid) { |
340 | sigprocmask_allsigs(SIG_UNBLOCK); | ||
341 | return pid; /* Parent or error */ | ||
342 | } | ||
343 | niro | 532 | |
344 | niro | 816 | /* Child */ |
345 | niro | 532 | |
346 | niro | 816 | /* Reset signal handlers that were set by the parent process */ |
347 | niro | 984 | reset_sighandlers_and_unblock_sigs(); |
348 | niro | 532 | |
349 | niro | 984 | /* Create a new session and make ourself the process group leader */ |
350 | niro | 816 | setsid(); |
351 | niro | 532 | |
352 | niro | 816 | /* Open the new terminal device */ |
353 | niro | 984 | if (!open_stdio_to_tty(a->terminal)) |
354 | _exit(EXIT_FAILURE); | ||
355 | niro | 532 | |
356 | niro | 816 | /* 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 | niro | 532 | /* |
366 | niro | 816 | * 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 | niro | 532 | */ |
373 | niro | 984 | dbg_message(L_LOG, "waiting for enter to start '%s'" |
374 | niro | 816 | "(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 | niro | 532 | |
381 | niro | 984 | /* |
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 | niro | 816 | if (ENABLE_FEATURE_INIT_COREDUMPS) { |
388 | niro | 984 | if (access("/.init_enable_core", F_OK) == 0) { |
389 | niro | 816 | struct rlimit limit; |
390 | limit.rlim_cur = RLIM_INFINITY; | ||
391 | limit.rlim_max = RLIM_INFINITY; | ||
392 | setrlimit(RLIMIT_CORE, &limit); | ||
393 | niro | 532 | } |
394 | niro | 816 | } |
395 | niro | 532 | |
396 | niro | 816 | /* Log the process name and args */ |
397 | message(L_LOG, "starting pid %d, tty '%s': '%s'", | ||
398 | getpid(), a->terminal, a->command); | ||
399 | niro | 532 | |
400 | niro | 816 | /* 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 | niro | 532 | } |
406 | |||
407 | niro | 984 | static struct init_action *mark_terminated(pid_t pid) |
408 | niro | 532 | { |
409 | niro | 984 | struct init_action *a; |
410 | niro | 532 | |
411 | niro | 984 | 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 | niro | 816 | } |
417 | niro | 532 | } |
418 | } | ||
419 | niro | 984 | return NULL; |
420 | niro | 532 | } |
421 | |||
422 | niro | 984 | static void waitfor(pid_t pid) |
423 | niro | 532 | { |
424 | niro | 984 | /* waitfor(run(x)): protect against failed fork inside run() */ |
425 | if (pid <= 0) | ||
426 | return; | ||
427 | niro | 532 | |
428 | niro | 984 | /* 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 | niro | 532 | } |
439 | } | ||
440 | |||
441 | niro | 984 | /* Run all commands of a particular type */ |
442 | static void run_actions(int action_type) | ||
443 | niro | 532 | { |
444 | niro | 816 | struct init_action *a; |
445 | |||
446 | for (a = init_action_list; a; a = a->next) { | ||
447 | niro | 984 | if (!(a->action_type & action_type)) |
448 | continue; | ||
449 | niro | 816 | |
450 | niro | 984 | 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 | niro | 816 | } |
455 | niro | 984 | 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 | niro | 816 | } |
463 | } | ||
464 | |||
465 | static void new_init_action(uint8_t action_type, const char *command, const char *cons) | ||
466 | niro | 532 | { |
467 | niro | 984 | struct init_action *a, **nextp; |
468 | niro | 532 | |
469 | niro | 984 | /* 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 | niro | 816 | ) { |
488 | niro | 984 | /* 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 | niro | 532 | } |
496 | niro | 984 | nextp = &a->next; |
497 | niro | 532 | } |
498 | niro | 816 | |
499 | niro | 984 | if (!a) |
500 | a = xzalloc(sizeof(*a)); | ||
501 | /* Append to the end of the list */ | ||
502 | *nextp = a; | ||
503 | niro | 816 | a->action_type = action_type; |
504 | safe_strncpy(a->command, command, sizeof(a->command)); | ||
505 | safe_strncpy(a->terminal, cons, sizeof(a->terminal)); | ||
506 | niro | 984 | dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n", |
507 | niro | 816 | a->command, a->action_type, a->terminal); |
508 | niro | 532 | } |
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 | niro | 816 | char *token[4]; |
521 | parser_t *parser = config_open2("/etc/inittab", fopen_for_read); | ||
522 | niro | 532 | |
523 | niro | 816 | if (parser == NULL) |
524 | #endif | ||
525 | { | ||
526 | niro | 984 | /* No inittab file - set up some default behavior */ |
527 | niro | 532 | /* Reboot on Ctrl-Alt-Del */ |
528 | niro | 816 | new_init_action(CTRLALTDEL, "reboot", ""); |
529 | niro | 532 | /* Umount all filesystems on halt/reboot */ |
530 | niro | 816 | new_init_action(SHUTDOWN, "umount -a -r", ""); |
531 | niro | 532 | /* Swapoff on halt/reboot */ |
532 | niro | 816 | 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 | niro | 532 | /* Askfirst shell on tty1-4 */ |
537 | new_init_action(ASKFIRST, bb_default_login_shell, ""); | ||
538 | niro | 816 | //TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users |
539 | niro | 532 | 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 | niro | 816 | #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 | niro | 984 | "sysinit\0""wait\0""once\0""respawn\0""askfirst\0" |
556 | niro | 816 | "ctrlaltdel\0""shutdown\0""restart\0"; |
557 | int action; | ||
558 | char *tty = token[0]; | ||
559 | niro | 532 | |
560 | niro | 816 | 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 | niro | 532 | } |
571 | niro | 816 | 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 | niro | 532 | } |
579 | niro | 816 | config_close(parser); |
580 | #endif | ||
581 | niro | 532 | } |
582 | |||
583 | niro | 984 | static void pause_and_low_level_reboot(unsigned magic) NORETURN; |
584 | static void pause_and_low_level_reboot(unsigned magic) | ||
585 | niro | 532 | { |
586 | niro | 984 | pid_t pid; |
587 | niro | 532 | |
588 | niro | 984 | /* Allow time for last message to reach serial console, etc */ |
589 | sleep(1); | ||
590 | niro | 532 | |
591 | niro | 984 | /* 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 | niro | 816 | for (a = init_action_list; a; a = a->next) { |
698 | niro | 984 | 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 | niro | 532 | } |
731 | niro | 984 | } |
732 | niro | 532 | |
733 | niro | 984 | /* 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 | niro | 532 | parse_inittab(); |
782 | |||
783 | niro | 984 | #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 | niro | 816 | /* NB: parent will wait in NOMMU case */ |
791 | if ((BB_MMU ? fork() : vfork()) == 0) { /* child */ | ||
792 | sleep(CONFIG_FEATURE_KILL_DELAY); | ||
793 | niro | 984 | for (a = init_action_list; a; a = a->next) |
794 | if (a->action_type == 0 && a->pid != 0) | ||
795 | kill(a->pid, SIGKILL); | ||
796 | niro | 816 | _exit(EXIT_SUCCESS); |
797 | } | ||
798 | niro | 984 | } |
799 | niro | 816 | #endif |
800 | |||
801 | niro | 984 | /* 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 | niro | 532 | } |
812 | } | ||
813 | niro | 984 | |
814 | /* Not needed: */ | ||
815 | /* run_actions(RESPAWN | ASKFIRST); */ | ||
816 | /* - we return to main loop, which does this automagically */ | ||
817 | niro | 532 | } |
818 | niro | 816 | #endif |
819 | niro | 532 | |
820 | niro | 984 | 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 | niro | 816 | int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
841 | int init_main(int argc UNUSED_PARAM, char **argv) | ||
842 | niro | 532 | { |
843 | niro | 984 | die_sleep = 30 * 24*60*60; /* if xmalloc would ever die... */ |
844 | niro | 532 | |
845 | niro | 984 | if (argv[1] && strcmp(argv[1], "-q") == 0) { |
846 | niro | 816 | return kill(1, SIGHUP); |
847 | niro | 532 | } |
848 | niro | 816 | |
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 | niro | 984 | /* Turn off rebooting via CTL-ALT-DEL - we get a |
857 | niro | 816 | * SIGINT on CAD so we can shut things down gracefully... */ |
858 | niro | 984 | reboot(RB_DISABLE_CAD); /* misnomer */ |
859 | niro | 532 | } |
860 | |||
861 | /* Figure out where the default console should be */ | ||
862 | console_init(); | ||
863 | niro | 816 | set_sane_term(); |
864 | xchdir("/"); | ||
865 | setsid(); | ||
866 | niro | 532 | |
867 | niro | 816 | /* 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 | niro | 532 | |
873 | niro | 816 | if (argv[1]) |
874 | xsetenv("RUNLEVEL", argv[1]); | ||
875 | niro | 532 | |
876 | niro | 984 | #if !ENABLE_FEATURE_EXTRA_QUIET |
877 | niro | 532 | /* Hello world */ |
878 | niro | 984 | message(L_CONSOLE | L_LOG, "init started: %s", bb_banner); |
879 | #endif | ||
880 | niro | 532 | |
881 | /* Make sure there is enough memory to do something useful. */ | ||
882 | if (ENABLE_SWAPONOFF) { | ||
883 | struct sysinfo info; | ||
884 | |||
885 | niro | 984 | if (sysinfo(&info) == 0 |
886 | && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024 | ||
887 | ) { | ||
888 | niro | 816 | message(L_CONSOLE, "Low memory, forcing swapon"); |
889 | niro | 532 | /* swapon -a requires /proc typically */ |
890 | niro | 816 | new_init_action(SYSINIT, "mount -t proc proc /proc", ""); |
891 | niro | 532 | /* Try to turn on swap */ |
892 | niro | 816 | new_init_action(SYSINIT, "swapon -a", ""); |
893 | niro | 532 | run_actions(SYSINIT); /* wait and removing */ |
894 | } | ||
895 | } | ||
896 | |||
897 | /* Check if we are supposed to be in single user mode */ | ||
898 | niro | 816 | if (argv[1] |
899 | niro | 984 | && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1')) |
900 | niro | 532 | ) { |
901 | niro | 816 | /* ??? shouldn't we set RUNLEVEL="b" here? */ |
902 | niro | 532 | /* Start a shell on console */ |
903 | new_init_action(RESPAWN, bb_default_login_shell, ""); | ||
904 | } else { | ||
905 | niro | 984 | /* Not in single user mode - see what inittab says */ |
906 | niro | 532 | |
907 | /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined, | ||
908 | * then parse_inittab() simply adds in some default | ||
909 | niro | 984 | * actions(i.e., INIT_SCRIPT and a pair |
910 | niro | 532 | * of "askfirst" shells */ |
911 | parse_inittab(); | ||
912 | } | ||
913 | |||
914 | #if ENABLE_SELINUX | ||
915 | if (getenv("SELINUX_INIT") == NULL) { | ||
916 | int enforce = 0; | ||
917 | |||
918 | niro | 816 | putenv((char*)"SELINUX_INIT=YES"); |
919 | niro | 532 | if (selinux_init_load_policy(&enforce) == 0) { |
920 | niro | 816 | BB_EXECVP(argv[0], argv); |
921 | niro | 532 | } else if (enforce > 0) { |
922 | /* SELinux in enforcing mode but load_policy failed */ | ||
923 | niro | 984 | message(L_CONSOLE, "can't load SELinux Policy. " |
924 | niro | 816 | "Machine is in enforcing mode. Halting now."); |
925 | exit(EXIT_FAILURE); | ||
926 | niro | 532 | } |
927 | } | ||
928 | niro | 984 | #endif |
929 | niro | 532 | |
930 | niro | 816 | /* 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 | niro | 532 | |
936 | niro | 984 | /* 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 | niro | 532 | /* Now run everything that needs to be run */ |
974 | /* First run the sysinit command */ | ||
975 | run_actions(SYSINIT); | ||
976 | niro | 984 | check_delayed_sigs(); |
977 | niro | 532 | /* Next run anything that wants to block */ |
978 | run_actions(WAIT); | ||
979 | niro | 984 | check_delayed_sigs(); |
980 | niro | 532 | /* Next run anything to be run only once */ |
981 | run_actions(ONCE); | ||
982 | |||
983 | niro | 984 | /* Now run the looping stuff for the rest of forever. |
984 | */ | ||
985 | while (1) { | ||
986 | int maybe_WNOHANG; | ||
987 | niro | 532 | |
988 | niro | 984 | maybe_WNOHANG = check_delayed_sigs(); |
989 | |||
990 | /* (Re)run the respawn/askfirst stuff */ | ||
991 | niro | 816 | run_actions(RESPAWN | ASKFIRST); |
992 | niro | 984 | maybe_WNOHANG |= check_delayed_sigs(); |
993 | niro | 532 | |
994 | niro | 984 | /* Don't consume all CPU time - sleep a bit */ |
995 | niro | 532 | sleep(1); |
996 | niro | 984 | maybe_WNOHANG |= check_delayed_sigs(); |
997 | niro | 532 | |
998 | niro | 984 | /* 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 | niro | 532 | } |
1024 | niro | 984 | /* See if anyone else is waiting to be reaped */ |
1025 | maybe_WNOHANG = WNOHANG; | ||
1026 | niro | 532 | } |
1027 | niro | 984 | } /* while (1) */ |
1028 | niro | 532 | } |