Annotation of /trunk/mkinitrd-magellan/busybox/init/init.c
Parent Directory | Revision Log
Revision 1520 -
(hide annotations)
(download)
Wed Sep 7 18:39:43 2011 UTC (12 years, 9 months ago) by niro
File MIME type: text/plain
File size: 28604 byte(s)
Wed Sep 7 18:39:43 2011 UTC (12 years, 9 months ago) by niro
File MIME type: text/plain
File size: 28604 byte(s)
-fixed build against linux-3.0
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 | 1520 | #include <sys/sysinfo.h> |
19 | niro | 1123 | #if ENABLE_FEATURE_UTMP |
20 | # include <utmp.h> /* DEAD_PROCESS */ | ||
21 | #endif | ||
22 | niro | 532 | |
23 | niro | 984 | |
24 | niro | 816 | /* Was a CONFIG_xxx option. A lot of people were building |
25 | * not fully functional init by switching it on! */ | ||
26 | #define DEBUG_INIT 0 | ||
27 | niro | 532 | |
28 | niro | 984 | #define COMMAND_SIZE 256 |
29 | niro | 816 | #define CONSOLE_NAME_SIZE 32 |
30 | niro | 532 | |
31 | niro | 984 | /* Default sysinit script. */ |
32 | niro | 532 | #ifndef INIT_SCRIPT |
33 | niro | 984 | #define INIT_SCRIPT "/etc/init.d/rcS" |
34 | niro | 532 | #endif |
35 | |||
36 | niro | 984 | /* Each type of actions can appear many times. They will be |
37 | * handled in order. RESTART is an exception, only 1st is used. | ||
38 | */ | ||
39 | /* Start these actions first and wait for completion */ | ||
40 | niro | 816 | #define SYSINIT 0x01 |
41 | niro | 984 | /* Start these after SYSINIT and wait for completion */ |
42 | #define WAIT 0x02 | ||
43 | /* Start these after WAIT and *dont* wait for completion */ | ||
44 | #define ONCE 0x04 | ||
45 | /* | ||
46 | * NB: while SYSINIT/WAIT/ONCE are being processed, | ||
47 | * SIGHUP ("reread /etc/inittab") will be processed only after | ||
48 | * each group of actions. If new inittab adds, say, a SYSINIT action, | ||
49 | * it will not be run, since init is already "past SYSINIT stage". | ||
50 | */ | ||
51 | /* Start these after ONCE are started, restart on exit */ | ||
52 | #define RESPAWN 0x08 | ||
53 | /* Like RESPAWN, but wait for <Enter> to be pressed on tty */ | ||
54 | #define ASKFIRST 0x10 | ||
55 | /* | ||
56 | * Start these on SIGINT, and wait for completion. | ||
57 | * Then go back to respawning RESPAWN and ASKFIRST actions. | ||
58 | * NB: kernel sends SIGINT to us if Ctrl-Alt-Del was pressed. | ||
59 | */ | ||
60 | niro | 816 | #define CTRLALTDEL 0x20 |
61 | niro | 984 | /* |
62 | * Start these before killing all processes in preparation for | ||
63 | * running RESTART actions or doing low-level halt/reboot/poweroff | ||
64 | * (initiated by SIGUSR1/SIGTERM/SIGUSR2). | ||
65 | * Wait for completion before proceeding. | ||
66 | */ | ||
67 | niro | 816 | #define SHUTDOWN 0x40 |
68 | niro | 984 | /* |
69 | * exec() on SIGQUIT. SHUTDOWN actions are started and waited for, | ||
70 | * then all processes are killed, then init exec's 1st RESTART action, | ||
71 | * replacing itself by it. If no RESTART action specified, | ||
72 | * SIGQUIT has no effect. | ||
73 | */ | ||
74 | niro | 816 | #define RESTART 0x80 |
75 | niro | 532 | |
76 | niro | 984 | |
77 | /* A linked list of init_actions, to be read from inittab */ | ||
78 | niro | 532 | struct init_action { |
79 | niro | 816 | struct init_action *next; |
80 | niro | 532 | pid_t pid; |
81 | niro | 816 | uint8_t action_type; |
82 | char terminal[CONSOLE_NAME_SIZE]; | ||
83 | char command[COMMAND_SIZE]; | ||
84 | niro | 532 | }; |
85 | |||
86 | static struct init_action *init_action_list = NULL; | ||
87 | |||
88 | niro | 816 | static const char *log_console = VC_5; |
89 | niro | 532 | |
90 | enum { | ||
91 | niro | 816 | L_LOG = 0x1, |
92 | L_CONSOLE = 0x2, | ||
93 | niro | 532 | #ifndef RB_HALT_SYSTEM |
94 | RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */ | ||
95 | RB_ENABLE_CAD = 0x89abcdef, | ||
96 | RB_DISABLE_CAD = 0, | ||
97 | RB_POWER_OFF = 0x4321fedc, | ||
98 | RB_AUTOBOOT = 0x01234567, | ||
99 | #endif | ||
100 | }; | ||
101 | |||
102 | /* Print a message to the specified device. | ||
103 | niro | 816 | * "where" may be bitwise-or'd from L_LOG | L_CONSOLE |
104 | * NB: careful, we can be called after vfork! | ||
105 | */ | ||
106 | niro | 984 | #define dbg_message(...) do { if (DEBUG_INIT) message(__VA_ARGS__); } while (0) |
107 | niro | 816 | static void message(int where, const char *fmt, ...) |
108 | niro | 532 | __attribute__ ((format(printf, 2, 3))); |
109 | niro | 816 | static void message(int where, const char *fmt, ...) |
110 | niro | 532 | { |
111 | va_list arguments; | ||
112 | niro | 816 | unsigned l; |
113 | char msg[128]; | ||
114 | niro | 532 | |
115 | msg[0] = '\r'; | ||
116 | niro | 816 | va_start(arguments, fmt); |
117 | l = 1 + vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments); | ||
118 | if (l > sizeof(msg) - 1) | ||
119 | l = sizeof(msg) - 1; | ||
120 | va_end(arguments); | ||
121 | niro | 532 | |
122 | niro | 984 | #if ENABLE_FEATURE_INIT_SYSLOG |
123 | msg[l] = '\0'; | ||
124 | if (where & L_LOG) { | ||
125 | /* Log the message to syslogd */ | ||
126 | openlog(applet_name, 0, LOG_DAEMON); | ||
127 | /* don't print "\r" */ | ||
128 | syslog(LOG_INFO, "%s", msg + 1); | ||
129 | closelog(); | ||
130 | } | ||
131 | msg[l++] = '\n'; | ||
132 | msg[l] = '\0'; | ||
133 | #else | ||
134 | { | ||
135 | static int log_fd = -1; | ||
136 | |||
137 | niro | 816 | msg[l++] = '\n'; |
138 | msg[l] = '\0'; | ||
139 | /* Take full control of the log tty, and never close it. | ||
140 | * It's mine, all mine! Muhahahaha! */ | ||
141 | if (log_fd < 0) { | ||
142 | if (!log_console) { | ||
143 | log_fd = STDERR_FILENO; | ||
144 | } else { | ||
145 | log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY); | ||
146 | if (log_fd < 0) { | ||
147 | bb_error_msg("can't log to %s", log_console); | ||
148 | where = L_CONSOLE; | ||
149 | } else { | ||
150 | close_on_exec_on(log_fd); | ||
151 | } | ||
152 | } | ||
153 | } | ||
154 | if (where & L_LOG) { | ||
155 | full_write(log_fd, msg, l); | ||
156 | if (log_fd == STDERR_FILENO) | ||
157 | return; /* don't print dup messages */ | ||
158 | } | ||
159 | niro | 532 | } |
160 | niro | 984 | #endif |
161 | niro | 532 | |
162 | niro | 816 | if (where & L_CONSOLE) { |
163 | /* Send console messages to console so people will see them. */ | ||
164 | full_write(STDERR_FILENO, msg, l); | ||
165 | niro | 532 | } |
166 | niro | 816 | } |
167 | niro | 532 | |
168 | niro | 816 | static void console_init(void) |
169 | { | ||
170 | niro | 984 | int vtno; |
171 | niro | 816 | char *s; |
172 | |||
173 | s = getenv("CONSOLE"); | ||
174 | if (!s) | ||
175 | s = getenv("console"); | ||
176 | if (s) { | ||
177 | int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY); | ||
178 | niro | 532 | if (fd >= 0) { |
179 | niro | 816 | dup2(fd, STDIN_FILENO); |
180 | dup2(fd, STDOUT_FILENO); | ||
181 | xmove_fd(fd, STDERR_FILENO); | ||
182 | niro | 532 | } |
183 | niro | 984 | dbg_message(L_LOG, "console='%s'", s); |
184 | niro | 816 | } else { |
185 | /* Make sure fd 0,1,2 are not closed | ||
186 | * (so that they won't be used by future opens) */ | ||
187 | bb_sanitize_stdio(); | ||
188 | // Users report problems | ||
189 | // /* Make sure init can't be blocked by writing to stderr */ | ||
190 | // fcntl(STDERR_FILENO, F_SETFL, fcntl(STDERR_FILENO, F_GETFL) | O_NONBLOCK); | ||
191 | niro | 532 | } |
192 | niro | 816 | |
193 | s = getenv("TERM"); | ||
194 | niro | 984 | if (ioctl(STDIN_FILENO, VT_OPENQRY, &vtno) != 0) { |
195 | /* Not a linux terminal, probably serial console. | ||
196 | * Force the TERM setting to vt102 | ||
197 | niro | 816 | * if TERM is set to linux (the default) */ |
198 | if (!s || strcmp(s, "linux") == 0) | ||
199 | putenv((char*)"TERM=vt102"); | ||
200 | if (!ENABLE_FEATURE_INIT_SYSLOG) | ||
201 | log_console = NULL; | ||
202 | } else if (!s) | ||
203 | putenv((char*)"TERM=linux"); | ||
204 | niro | 532 | } |
205 | |||
206 | niro | 816 | /* Set terminal settings to reasonable defaults. |
207 | * NB: careful, we can be called after vfork! */ | ||
208 | static void set_sane_term(void) | ||
209 | niro | 532 | { |
210 | struct termios tty; | ||
211 | |||
212 | tcgetattr(STDIN_FILENO, &tty); | ||
213 | |||
214 | /* set control chars */ | ||
215 | tty.c_cc[VINTR] = 3; /* C-c */ | ||
216 | tty.c_cc[VQUIT] = 28; /* C-\ */ | ||
217 | tty.c_cc[VERASE] = 127; /* C-? */ | ||
218 | tty.c_cc[VKILL] = 21; /* C-u */ | ||
219 | tty.c_cc[VEOF] = 4; /* C-d */ | ||
220 | tty.c_cc[VSTART] = 17; /* C-q */ | ||
221 | tty.c_cc[VSTOP] = 19; /* C-s */ | ||
222 | tty.c_cc[VSUSP] = 26; /* C-z */ | ||
223 | |||
224 | niro | 816 | /* use line discipline 0 */ |
225 | niro | 532 | tty.c_line = 0; |
226 | |||
227 | /* Make it be sane */ | ||
228 | tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD; | ||
229 | tty.c_cflag |= CREAD | HUPCL | CLOCAL; | ||
230 | |||
231 | /* input modes */ | ||
232 | tty.c_iflag = ICRNL | IXON | IXOFF; | ||
233 | |||
234 | /* output modes */ | ||
235 | tty.c_oflag = OPOST | ONLCR; | ||
236 | |||
237 | /* local modes */ | ||
238 | tty.c_lflag = | ||
239 | ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN; | ||
240 | |||
241 | niro | 816 | tcsetattr_stdin_TCSANOW(&tty); |
242 | niro | 532 | } |
243 | |||
244 | niro | 816 | /* Open the new terminal device. |
245 | * NB: careful, we can be called after vfork! */ | ||
246 | niro | 984 | static int open_stdio_to_tty(const char* tty_name) |
247 | niro | 532 | { |
248 | niro | 816 | /* empty tty_name means "use init's tty", else... */ |
249 | if (tty_name[0]) { | ||
250 | int fd; | ||
251 | niro | 984 | |
252 | niro | 816 | close(STDIN_FILENO); |
253 | /* fd can be only < 0 or 0: */ | ||
254 | fd = device_open(tty_name, O_RDWR); | ||
255 | if (fd) { | ||
256 | message(L_LOG | L_CONSOLE, "can't open %s: %s", | ||
257 | tty_name, strerror(errno)); | ||
258 | niro | 984 | return 0; /* failure */ |
259 | niro | 532 | } |
260 | niro | 816 | dup2(STDIN_FILENO, STDOUT_FILENO); |
261 | dup2(STDIN_FILENO, STDERR_FILENO); | ||
262 | niro | 532 | } |
263 | niro | 816 | set_sane_term(); |
264 | niro | 984 | return 1; /* success */ |
265 | niro | 532 | } |
266 | |||
267 | niro | 984 | static void reset_sighandlers_and_unblock_sigs(void) |
268 | { | ||
269 | bb_signals(0 | ||
270 | + (1 << SIGUSR1) | ||
271 | + (1 << SIGUSR2) | ||
272 | + (1 << SIGTERM) | ||
273 | + (1 << SIGQUIT) | ||
274 | + (1 << SIGINT) | ||
275 | + (1 << SIGHUP) | ||
276 | + (1 << SIGTSTP) | ||
277 | + (1 << SIGSTOP) | ||
278 | , SIG_DFL); | ||
279 | sigprocmask_allsigs(SIG_UNBLOCK); | ||
280 | } | ||
281 | |||
282 | niro | 816 | /* Wrapper around exec: |
283 | * Takes string (max COMMAND_SIZE chars). | ||
284 | * If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'. | ||
285 | * Otherwise splits words on whitespace, deals with leading dash, | ||
286 | * and uses plain exec(). | ||
287 | * NB: careful, we can be called after vfork! | ||
288 | */ | ||
289 | static void init_exec(const char *command) | ||
290 | niro | 532 | { |
291 | niro | 816 | char *cmd[COMMAND_SIZE / 2]; |
292 | char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */ | ||
293 | int dash = (command[0] == '-' /* maybe? && command[1] == '/' */); | ||
294 | niro | 532 | |
295 | niro | 816 | /* See if any special /bin/sh requiring characters are present */ |
296 | if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) { | ||
297 | strcpy(buf, "exec "); | ||
298 | strcpy(buf + 5, command + dash); /* excluding "-" */ | ||
299 | /* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */ | ||
300 | cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash); | ||
301 | cmd[1] = (char*)"-c"; | ||
302 | cmd[2] = buf; | ||
303 | cmd[3] = NULL; | ||
304 | } else { | ||
305 | /* Convert command (char*) into cmd (char**, one word per string) */ | ||
306 | char *word, *next; | ||
307 | int i = 0; | ||
308 | next = strcpy(buf, command); /* including "-" */ | ||
309 | while ((word = strsep(&next, " \t")) != NULL) { | ||
310 | if (*word != '\0') { /* not two spaces/tabs together? */ | ||
311 | cmd[i] = word; | ||
312 | i++; | ||
313 | } | ||
314 | niro | 532 | } |
315 | niro | 816 | cmd[i] = NULL; |
316 | niro | 532 | } |
317 | niro | 816 | /* If we saw leading "-", it is interactive shell. |
318 | * Try harder to give it a controlling tty. | ||
319 | * And skip "-" in actual exec call. */ | ||
320 | if (dash) { | ||
321 | /* _Attempt_ to make stdin a controlling tty. */ | ||
322 | if (ENABLE_FEATURE_INIT_SCTTY) | ||
323 | ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/); | ||
324 | } | ||
325 | BB_EXECVP(cmd[0] + dash, cmd); | ||
326 | niro | 984 | message(L_LOG | L_CONSOLE, "can't run '%s': %s", cmd[0], strerror(errno)); |
327 | niro | 816 | /* returns if execvp fails */ |
328 | niro | 532 | } |
329 | |||
330 | niro | 816 | /* Used only by run_actions */ |
331 | niro | 532 | static pid_t run(const struct init_action *a) |
332 | { | ||
333 | pid_t pid; | ||
334 | |||
335 | niro | 984 | /* Careful: don't be affected by a signal in vforked child */ |
336 | sigprocmask_allsigs(SIG_BLOCK); | ||
337 | niro | 816 | if (BB_MMU && (a->action_type & ASKFIRST)) |
338 | pid = fork(); | ||
339 | else | ||
340 | pid = vfork(); | ||
341 | if (pid < 0) | ||
342 | message(L_LOG | L_CONSOLE, "can't fork"); | ||
343 | niro | 984 | if (pid) { |
344 | sigprocmask_allsigs(SIG_UNBLOCK); | ||
345 | return pid; /* Parent or error */ | ||
346 | } | ||
347 | niro | 532 | |
348 | niro | 816 | /* Child */ |
349 | niro | 532 | |
350 | niro | 816 | /* Reset signal handlers that were set by the parent process */ |
351 | niro | 984 | reset_sighandlers_and_unblock_sigs(); |
352 | niro | 532 | |
353 | niro | 984 | /* Create a new session and make ourself the process group leader */ |
354 | niro | 816 | setsid(); |
355 | niro | 532 | |
356 | niro | 816 | /* Open the new terminal device */ |
357 | niro | 984 | if (!open_stdio_to_tty(a->terminal)) |
358 | _exit(EXIT_FAILURE); | ||
359 | niro | 532 | |
360 | niro | 816 | /* NB: on NOMMU we can't wait for input in child, so |
361 | * "askfirst" will work the same as "respawn". */ | ||
362 | if (BB_MMU && (a->action_type & ASKFIRST)) { | ||
363 | static const char press_enter[] ALIGN1 = | ||
364 | #ifdef CUSTOMIZED_BANNER | ||
365 | #include CUSTOMIZED_BANNER | ||
366 | #endif | ||
367 | "\nPlease press Enter to activate this console. "; | ||
368 | char c; | ||
369 | niro | 532 | /* |
370 | niro | 816 | * Save memory by not exec-ing anything large (like a shell) |
371 | * before the user wants it. This is critical if swap is not | ||
372 | * enabled and the system has low memory. Generally this will | ||
373 | * be run on the second virtual console, and the first will | ||
374 | * be allowed to start a shell or whatever an init script | ||
375 | * specifies. | ||
376 | niro | 532 | */ |
377 | niro | 984 | dbg_message(L_LOG, "waiting for enter to start '%s'" |
378 | niro | 816 | "(pid %d, tty '%s')\n", |
379 | a->command, getpid(), a->terminal); | ||
380 | full_write(STDOUT_FILENO, press_enter, sizeof(press_enter) - 1); | ||
381 | while (safe_read(STDIN_FILENO, &c, 1) == 1 && c != '\n') | ||
382 | continue; | ||
383 | } | ||
384 | niro | 532 | |
385 | niro | 984 | /* |
386 | * When a file named /.init_enable_core exists, setrlimit is called | ||
387 | * before processes are spawned to set core file size as unlimited. | ||
388 | * This is for debugging only. Don't use this is production, unless | ||
389 | * you want core dumps lying about.... | ||
390 | */ | ||
391 | niro | 816 | if (ENABLE_FEATURE_INIT_COREDUMPS) { |
392 | niro | 984 | if (access("/.init_enable_core", F_OK) == 0) { |
393 | niro | 816 | struct rlimit limit; |
394 | limit.rlim_cur = RLIM_INFINITY; | ||
395 | limit.rlim_max = RLIM_INFINITY; | ||
396 | setrlimit(RLIMIT_CORE, &limit); | ||
397 | niro | 532 | } |
398 | niro | 816 | } |
399 | niro | 532 | |
400 | niro | 816 | /* Log the process name and args */ |
401 | message(L_LOG, "starting pid %d, tty '%s': '%s'", | ||
402 | getpid(), a->terminal, a->command); | ||
403 | niro | 532 | |
404 | niro | 816 | /* Now run it. The new program will take over this PID, |
405 | * so nothing further in init.c should be run. */ | ||
406 | init_exec(a->command); | ||
407 | /* We're still here? Some error happened. */ | ||
408 | _exit(-1); | ||
409 | niro | 532 | } |
410 | |||
411 | niro | 984 | static struct init_action *mark_terminated(pid_t pid) |
412 | niro | 532 | { |
413 | niro | 984 | struct init_action *a; |
414 | niro | 532 | |
415 | niro | 984 | if (pid > 0) { |
416 | for (a = init_action_list; a; a = a->next) { | ||
417 | if (a->pid == pid) { | ||
418 | a->pid = 0; | ||
419 | return a; | ||
420 | niro | 816 | } |
421 | niro | 532 | } |
422 | niro | 1123 | update_utmp(pid, DEAD_PROCESS, /*tty_name:*/ NULL, /*username:*/ NULL, /*hostname:*/ NULL); |
423 | niro | 532 | } |
424 | niro | 984 | return NULL; |
425 | niro | 532 | } |
426 | |||
427 | niro | 984 | static void waitfor(pid_t pid) |
428 | niro | 532 | { |
429 | niro | 984 | /* waitfor(run(x)): protect against failed fork inside run() */ |
430 | if (pid <= 0) | ||
431 | return; | ||
432 | niro | 532 | |
433 | niro | 984 | /* Wait for any child (prevent zombies from exiting orphaned processes) |
434 | * but exit the loop only when specified one has exited. */ | ||
435 | while (1) { | ||
436 | pid_t wpid = wait(NULL); | ||
437 | mark_terminated(wpid); | ||
438 | /* Unsafe. SIGTSTP handler might have wait'ed it already */ | ||
439 | /*if (wpid == pid) break;*/ | ||
440 | /* More reliable: */ | ||
441 | if (kill(pid, 0)) | ||
442 | break; | ||
443 | niro | 532 | } |
444 | } | ||
445 | |||
446 | niro | 984 | /* Run all commands of a particular type */ |
447 | static void run_actions(int action_type) | ||
448 | niro | 532 | { |
449 | niro | 816 | struct init_action *a; |
450 | |||
451 | for (a = init_action_list; a; a = a->next) { | ||
452 | niro | 984 | if (!(a->action_type & action_type)) |
453 | continue; | ||
454 | niro | 816 | |
455 | niro | 984 | if (a->action_type & (SYSINIT | WAIT | ONCE | CTRLALTDEL | SHUTDOWN)) { |
456 | pid_t pid = run(a); | ||
457 | if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN)) | ||
458 | waitfor(pid); | ||
459 | niro | 816 | } |
460 | niro | 984 | if (a->action_type & (RESPAWN | ASKFIRST)) { |
461 | /* Only run stuff with pid == 0. If pid != 0, | ||
462 | * it is already running | ||
463 | */ | ||
464 | if (a->pid == 0) | ||
465 | a->pid = run(a); | ||
466 | } | ||
467 | niro | 816 | } |
468 | } | ||
469 | |||
470 | static void new_init_action(uint8_t action_type, const char *command, const char *cons) | ||
471 | niro | 532 | { |
472 | niro | 984 | struct init_action *a, **nextp; |
473 | niro | 532 | |
474 | niro | 984 | /* Scenario: |
475 | * old inittab: | ||
476 | * ::shutdown:umount -a -r | ||
477 | * ::shutdown:swapoff -a | ||
478 | * new inittab: | ||
479 | * ::shutdown:swapoff -a | ||
480 | * ::shutdown:umount -a -r | ||
481 | * On reload, we must ensure entries end up in correct order. | ||
482 | * To achieve that, if we find a matching entry, we move it | ||
483 | * to the end. | ||
484 | */ | ||
485 | nextp = &init_action_list; | ||
486 | while ((a = *nextp) != NULL) { | ||
487 | /* Don't enter action if it's already in the list, | ||
488 | * This prevents losing running RESPAWNs. | ||
489 | */ | ||
490 | if (strcmp(a->command, command) == 0 | ||
491 | && strcmp(a->terminal, cons) == 0 | ||
492 | niro | 816 | ) { |
493 | niro | 984 | /* Remove from list */ |
494 | *nextp = a->next; | ||
495 | /* Find the end of the list */ | ||
496 | while (*nextp != NULL) | ||
497 | nextp = &(*nextp)->next; | ||
498 | a->next = NULL; | ||
499 | break; | ||
500 | niro | 532 | } |
501 | niro | 984 | nextp = &a->next; |
502 | niro | 532 | } |
503 | niro | 816 | |
504 | niro | 984 | if (!a) |
505 | a = xzalloc(sizeof(*a)); | ||
506 | /* Append to the end of the list */ | ||
507 | *nextp = a; | ||
508 | niro | 816 | a->action_type = action_type; |
509 | safe_strncpy(a->command, command, sizeof(a->command)); | ||
510 | safe_strncpy(a->terminal, cons, sizeof(a->terminal)); | ||
511 | niro | 984 | dbg_message(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n", |
512 | niro | 816 | a->command, a->action_type, a->terminal); |
513 | niro | 532 | } |
514 | |||
515 | /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined, | ||
516 | * then parse_inittab() simply adds in some default | ||
517 | * actions(i.e., runs INIT_SCRIPT and then starts a pair | ||
518 | * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB | ||
519 | * _is_ defined, but /etc/inittab is missing, this | ||
520 | * results in the same set of default behaviors. | ||
521 | */ | ||
522 | static void parse_inittab(void) | ||
523 | { | ||
524 | #if ENABLE_FEATURE_USE_INITTAB | ||
525 | niro | 816 | char *token[4]; |
526 | parser_t *parser = config_open2("/etc/inittab", fopen_for_read); | ||
527 | niro | 532 | |
528 | niro | 816 | if (parser == NULL) |
529 | #endif | ||
530 | { | ||
531 | niro | 984 | /* No inittab file - set up some default behavior */ |
532 | niro | 532 | /* Reboot on Ctrl-Alt-Del */ |
533 | niro | 816 | new_init_action(CTRLALTDEL, "reboot", ""); |
534 | niro | 532 | /* Umount all filesystems on halt/reboot */ |
535 | niro | 816 | new_init_action(SHUTDOWN, "umount -a -r", ""); |
536 | niro | 532 | /* Swapoff on halt/reboot */ |
537 | niro | 816 | if (ENABLE_SWAPONOFF) |
538 | new_init_action(SHUTDOWN, "swapoff -a", ""); | ||
539 | /* Prepare to restart init when a QUIT is received */ | ||
540 | new_init_action(RESTART, "init", ""); | ||
541 | niro | 532 | /* Askfirst shell on tty1-4 */ |
542 | new_init_action(ASKFIRST, bb_default_login_shell, ""); | ||
543 | niro | 816 | //TODO: VC_1 instead of ""? "" is console -> ctty problems -> angry users |
544 | niro | 532 | new_init_action(ASKFIRST, bb_default_login_shell, VC_2); |
545 | new_init_action(ASKFIRST, bb_default_login_shell, VC_3); | ||
546 | new_init_action(ASKFIRST, bb_default_login_shell, VC_4); | ||
547 | /* sysinit */ | ||
548 | new_init_action(SYSINIT, INIT_SCRIPT, ""); | ||
549 | return; | ||
550 | } | ||
551 | |||
552 | niro | 816 | #if ENABLE_FEATURE_USE_INITTAB |
553 | /* optional_tty:ignored_runlevel:action:command | ||
554 | * Delims are not to be collapsed and need exactly 4 tokens | ||
555 | */ | ||
556 | while (config_read(parser, token, 4, 0, "#:", | ||
557 | PARSE_NORMAL & ~(PARSE_TRIM | PARSE_COLLAPSE))) { | ||
558 | /* order must correspond to SYSINIT..RESTART constants */ | ||
559 | static const char actions[] ALIGN1 = | ||
560 | niro | 984 | "sysinit\0""wait\0""once\0""respawn\0""askfirst\0" |
561 | niro | 816 | "ctrlaltdel\0""shutdown\0""restart\0"; |
562 | int action; | ||
563 | char *tty = token[0]; | ||
564 | niro | 532 | |
565 | niro | 816 | if (!token[3]) /* less than 4 tokens */ |
566 | goto bad_entry; | ||
567 | action = index_in_strings(actions, token[2]); | ||
568 | if (action < 0 || !token[3][0]) /* token[3]: command */ | ||
569 | goto bad_entry; | ||
570 | /* turn .*TTY -> /dev/TTY */ | ||
571 | if (tty[0]) { | ||
572 | niro | 1123 | tty = concat_path_file("/dev/", skip_dev_pfx(tty)); |
573 | niro | 532 | } |
574 | niro | 816 | new_init_action(1 << action, token[3], tty); |
575 | if (tty[0]) | ||
576 | free(tty); | ||
577 | continue; | ||
578 | bad_entry: | ||
579 | message(L_LOG | L_CONSOLE, "Bad inittab entry at line %d", | ||
580 | parser->lineno); | ||
581 | niro | 532 | } |
582 | niro | 816 | config_close(parser); |
583 | #endif | ||
584 | niro | 532 | } |
585 | |||
586 | niro | 984 | static void pause_and_low_level_reboot(unsigned magic) NORETURN; |
587 | static void pause_and_low_level_reboot(unsigned magic) | ||
588 | niro | 532 | { |
589 | niro | 984 | pid_t pid; |
590 | niro | 532 | |
591 | niro | 984 | /* Allow time for last message to reach serial console, etc */ |
592 | sleep(1); | ||
593 | niro | 532 | |
594 | niro | 984 | /* We have to fork here, since the kernel calls do_exit(EXIT_SUCCESS) |
595 | * in linux/kernel/sys.c, which can cause the machine to panic when | ||
596 | * the init process exits... */ | ||
597 | pid = vfork(); | ||
598 | if (pid == 0) { /* child */ | ||
599 | reboot(magic); | ||
600 | _exit(EXIT_SUCCESS); | ||
601 | } | ||
602 | while (1) | ||
603 | sleep(1); | ||
604 | } | ||
605 | |||
606 | static void run_shutdown_and_kill_processes(void) | ||
607 | { | ||
608 | /* Run everything to be run at "shutdown". This is done _prior_ | ||
609 | * to killing everything, in case people wish to use scripts to | ||
610 | * shut things down gracefully... */ | ||
611 | run_actions(SHUTDOWN); | ||
612 | |||
613 | message(L_CONSOLE | L_LOG, "The system is going down NOW!"); | ||
614 | |||
615 | /* Send signals to every process _except_ pid 1 */ | ||
616 | kill(-1, SIGTERM); | ||
617 | message(L_CONSOLE | L_LOG, "Sent SIG%s to all processes", "TERM"); | ||
618 | sync(); | ||
619 | sleep(1); | ||
620 | |||
621 | kill(-1, SIGKILL); | ||
622 | message(L_CONSOLE, "Sent SIG%s to all processes", "KILL"); | ||
623 | sync(); | ||
624 | /*sleep(1); - callers take care about making a pause */ | ||
625 | } | ||
626 | |||
627 | /* Signal handling by init: | ||
628 | * | ||
629 | * For process with PID==1, on entry kernel sets all signals to SIG_DFL | ||
630 | * and unmasks all signals. However, for process with PID==1, | ||
631 | * default action (SIG_DFL) on any signal is to ignore it, | ||
632 | * even for special signals SIGKILL and SIGCONT. | ||
633 | * Also, any signal can be caught or blocked. | ||
634 | * (but SIGSTOP is still handled specially, at least in 2.6.20) | ||
635 | * | ||
636 | * We install two kinds of handlers, "immediate" and "delayed". | ||
637 | * | ||
638 | * Immediate handlers execute at any time, even while, say, sysinit | ||
639 | * is running. | ||
640 | * | ||
641 | * Delayed handlers just set a flag variable. The variable is checked | ||
642 | * in the main loop and acted upon. | ||
643 | * | ||
644 | * halt/poweroff/reboot and restart have immediate handlers. | ||
645 | * They only traverse linked list of struct action's, never modify it, | ||
646 | * this should be safe to do even in signal handler. Also they | ||
647 | * never return. | ||
648 | * | ||
649 | * SIGSTOP and SIGTSTP have immediate handlers. They just wait | ||
650 | * for SIGCONT to happen. | ||
651 | * | ||
652 | * SIGHUP has a delayed handler, because modifying linked list | ||
653 | * of struct action's from a signal handler while it is manipulated | ||
654 | * by the program may be disastrous. | ||
655 | * | ||
656 | * Ctrl-Alt-Del has a delayed handler. Not a must, but allowing | ||
657 | * it to happen even somewhere inside "sysinit" would be a bit awkward. | ||
658 | * | ||
659 | * There is a tiny probability that SIGHUP and Ctrl-Alt-Del will collide | ||
660 | * and only one will be remembered and acted upon. | ||
661 | */ | ||
662 | |||
663 | /* The SIGUSR[12]/SIGTERM handler */ | ||
664 | static void halt_reboot_pwoff(int sig) NORETURN; | ||
665 | static void halt_reboot_pwoff(int sig) | ||
666 | { | ||
667 | const char *m; | ||
668 | unsigned rb; | ||
669 | |||
670 | /* We may call run() and it unmasks signals, | ||
671 | * including the one masked inside this signal handler. | ||
672 | * Testcase which would start multiple reboot scripts: | ||
673 | * while true; do reboot; done | ||
674 | * Preventing it: | ||
675 | */ | ||
676 | reset_sighandlers_and_unblock_sigs(); | ||
677 | |||
678 | run_shutdown_and_kill_processes(); | ||
679 | |||
680 | m = "halt"; | ||
681 | rb = RB_HALT_SYSTEM; | ||
682 | if (sig == SIGTERM) { | ||
683 | m = "reboot"; | ||
684 | rb = RB_AUTOBOOT; | ||
685 | } else if (sig == SIGUSR2) { | ||
686 | m = "poweroff"; | ||
687 | rb = RB_POWER_OFF; | ||
688 | } | ||
689 | message(L_CONSOLE, "Requesting system %s", m); | ||
690 | pause_and_low_level_reboot(rb); | ||
691 | /* not reached */ | ||
692 | } | ||
693 | |||
694 | /* Handler for QUIT - exec "restart" action, | ||
695 | * else (no such action defined) do nothing */ | ||
696 | static void restart_handler(int sig UNUSED_PARAM) | ||
697 | { | ||
698 | struct init_action *a; | ||
699 | |||
700 | niro | 816 | for (a = init_action_list; a; a = a->next) { |
701 | niro | 984 | if (!(a->action_type & RESTART)) |
702 | continue; | ||
703 | |||
704 | /* Starting from here, we won't return. | ||
705 | * Thus don't need to worry about preserving errno | ||
706 | * and such. | ||
707 | */ | ||
708 | |||
709 | reset_sighandlers_and_unblock_sigs(); | ||
710 | |||
711 | run_shutdown_and_kill_processes(); | ||
712 | |||
713 | /* Allow Ctrl-Alt-Del to reboot the system. | ||
714 | * This is how kernel sets it up for init, we follow suit. | ||
715 | */ | ||
716 | reboot(RB_ENABLE_CAD); /* misnomer */ | ||
717 | |||
718 | if (open_stdio_to_tty(a->terminal)) { | ||
719 | dbg_message(L_CONSOLE, "Trying to re-exec %s", a->command); | ||
720 | /* Theoretically should be safe. | ||
721 | * But in practice, kernel bugs may leave | ||
722 | * unkillable processes, and wait() may block forever. | ||
723 | * Oh well. Hoping "new" init won't be too surprised | ||
724 | * by having children it didn't create. | ||
725 | */ | ||
726 | //while (wait(NULL) > 0) | ||
727 | // continue; | ||
728 | init_exec(a->command); | ||
729 | } | ||
730 | /* Open or exec failed */ | ||
731 | pause_and_low_level_reboot(RB_HALT_SYSTEM); | ||
732 | /* not reached */ | ||
733 | niro | 532 | } |
734 | niro | 984 | } |
735 | niro | 532 | |
736 | niro | 984 | /* The SIGSTOP/SIGTSTP handler |
737 | * NB: inside it, all signals except SIGCONT are masked | ||
738 | * via appropriate setup in sigaction(). | ||
739 | */ | ||
740 | static void stop_handler(int sig UNUSED_PARAM) | ||
741 | { | ||
742 | smallint saved_bb_got_signal; | ||
743 | int saved_errno; | ||
744 | |||
745 | saved_bb_got_signal = bb_got_signal; | ||
746 | saved_errno = errno; | ||
747 | signal(SIGCONT, record_signo); | ||
748 | |||
749 | while (1) { | ||
750 | pid_t wpid; | ||
751 | |||
752 | if (bb_got_signal == SIGCONT) | ||
753 | break; | ||
754 | /* NB: this can accidentally wait() for a process | ||
755 | * which we waitfor() elsewhere! waitfor() must have | ||
756 | * code which is resilient against this. | ||
757 | */ | ||
758 | wpid = wait_any_nohang(NULL); | ||
759 | mark_terminated(wpid); | ||
760 | sleep(1); | ||
761 | } | ||
762 | |||
763 | signal(SIGCONT, SIG_DFL); | ||
764 | errno = saved_errno; | ||
765 | bb_got_signal = saved_bb_got_signal; | ||
766 | } | ||
767 | |||
768 | #if ENABLE_FEATURE_USE_INITTAB | ||
769 | static void reload_inittab(void) | ||
770 | { | ||
771 | struct init_action *a, **nextp; | ||
772 | |||
773 | message(L_LOG, "reloading /etc/inittab"); | ||
774 | |||
775 | /* Disable old entries */ | ||
776 | for (a = init_action_list; a; a = a->next) | ||
777 | a->action_type = 0; | ||
778 | |||
779 | /* Append new entries, or modify existing entries | ||
780 | * (incl. setting a->action_type) if cmd and device name | ||
781 | * match new ones. End result: only entries with | ||
782 | * a->action_type == 0 are stale. | ||
783 | */ | ||
784 | niro | 532 | parse_inittab(); |
785 | |||
786 | niro | 984 | #if ENABLE_FEATURE_KILL_REMOVED |
787 | /* Kill stale entries */ | ||
788 | /* Be nice and send SIGTERM first */ | ||
789 | for (a = init_action_list; a; a = a->next) | ||
790 | if (a->action_type == 0 && a->pid != 0) | ||
791 | kill(a->pid, SIGTERM); | ||
792 | if (CONFIG_FEATURE_KILL_DELAY) { | ||
793 | niro | 816 | /* NB: parent will wait in NOMMU case */ |
794 | if ((BB_MMU ? fork() : vfork()) == 0) { /* child */ | ||
795 | sleep(CONFIG_FEATURE_KILL_DELAY); | ||
796 | niro | 984 | for (a = init_action_list; a; a = a->next) |
797 | if (a->action_type == 0 && a->pid != 0) | ||
798 | kill(a->pid, SIGKILL); | ||
799 | niro | 816 | _exit(EXIT_SUCCESS); |
800 | } | ||
801 | niro | 984 | } |
802 | niro | 816 | #endif |
803 | |||
804 | niro | 984 | /* Remove stale entries and SYSINIT entries. |
805 | * We never rerun SYSINIT entries anyway, | ||
806 | * removing them too saves a few bytes */ | ||
807 | nextp = &init_action_list; | ||
808 | while ((a = *nextp) != NULL) { | ||
809 | if ((a->action_type & ~SYSINIT) == 0) { | ||
810 | *nextp = a->next; | ||
811 | free(a); | ||
812 | } else { | ||
813 | nextp = &a->next; | ||
814 | niro | 532 | } |
815 | } | ||
816 | niro | 984 | |
817 | /* Not needed: */ | ||
818 | /* run_actions(RESPAWN | ASKFIRST); */ | ||
819 | /* - we return to main loop, which does this automagically */ | ||
820 | niro | 532 | } |
821 | niro | 816 | #endif |
822 | niro | 532 | |
823 | niro | 984 | static int check_delayed_sigs(void) |
824 | { | ||
825 | int sigs_seen = 0; | ||
826 | |||
827 | while (1) { | ||
828 | smallint sig = bb_got_signal; | ||
829 | |||
830 | if (!sig) | ||
831 | return sigs_seen; | ||
832 | bb_got_signal = 0; | ||
833 | sigs_seen = 1; | ||
834 | #if ENABLE_FEATURE_USE_INITTAB | ||
835 | if (sig == SIGHUP) | ||
836 | reload_inittab(); | ||
837 | #endif | ||
838 | if (sig == SIGINT) | ||
839 | run_actions(CTRLALTDEL); | ||
840 | } | ||
841 | } | ||
842 | |||
843 | niro | 816 | int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
844 | int init_main(int argc UNUSED_PARAM, char **argv) | ||
845 | niro | 532 | { |
846 | niro | 984 | die_sleep = 30 * 24*60*60; /* if xmalloc would ever die... */ |
847 | niro | 532 | |
848 | niro | 984 | if (argv[1] && strcmp(argv[1], "-q") == 0) { |
849 | niro | 816 | return kill(1, SIGHUP); |
850 | niro | 532 | } |
851 | niro | 816 | |
852 | if (!DEBUG_INIT) { | ||
853 | /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */ | ||
854 | if (getpid() != 1 | ||
855 | && (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc")) | ||
856 | ) { | ||
857 | bb_show_usage(); | ||
858 | } | ||
859 | niro | 984 | /* Turn off rebooting via CTL-ALT-DEL - we get a |
860 | niro | 816 | * SIGINT on CAD so we can shut things down gracefully... */ |
861 | niro | 984 | reboot(RB_DISABLE_CAD); /* misnomer */ |
862 | niro | 532 | } |
863 | |||
864 | /* Figure out where the default console should be */ | ||
865 | console_init(); | ||
866 | niro | 816 | set_sane_term(); |
867 | xchdir("/"); | ||
868 | setsid(); | ||
869 | niro | 532 | |
870 | niro | 816 | /* Make sure environs is set to something sane */ |
871 | putenv((char *) "HOME=/"); | ||
872 | putenv((char *) bb_PATH_root_path); | ||
873 | putenv((char *) "SHELL=/bin/sh"); | ||
874 | putenv((char *) "USER=root"); /* needed? why? */ | ||
875 | niro | 532 | |
876 | niro | 816 | if (argv[1]) |
877 | xsetenv("RUNLEVEL", argv[1]); | ||
878 | niro | 532 | |
879 | niro | 984 | #if !ENABLE_FEATURE_EXTRA_QUIET |
880 | niro | 532 | /* Hello world */ |
881 | niro | 984 | message(L_CONSOLE | L_LOG, "init started: %s", bb_banner); |
882 | #endif | ||
883 | niro | 532 | |
884 | /* Make sure there is enough memory to do something useful. */ | ||
885 | if (ENABLE_SWAPONOFF) { | ||
886 | struct sysinfo info; | ||
887 | |||
888 | niro | 984 | if (sysinfo(&info) == 0 |
889 | && (info.mem_unit ? info.mem_unit : 1) * (long long)info.totalram < 1024*1024 | ||
890 | ) { | ||
891 | niro | 816 | message(L_CONSOLE, "Low memory, forcing swapon"); |
892 | niro | 532 | /* swapon -a requires /proc typically */ |
893 | niro | 816 | new_init_action(SYSINIT, "mount -t proc proc /proc", ""); |
894 | niro | 532 | /* Try to turn on swap */ |
895 | niro | 816 | new_init_action(SYSINIT, "swapon -a", ""); |
896 | niro | 532 | run_actions(SYSINIT); /* wait and removing */ |
897 | } | ||
898 | } | ||
899 | |||
900 | /* Check if we are supposed to be in single user mode */ | ||
901 | niro | 816 | if (argv[1] |
902 | niro | 984 | && (strcmp(argv[1], "single") == 0 || strcmp(argv[1], "-s") == 0 || LONE_CHAR(argv[1], '1')) |
903 | niro | 532 | ) { |
904 | niro | 816 | /* ??? shouldn't we set RUNLEVEL="b" here? */ |
905 | niro | 532 | /* Start a shell on console */ |
906 | new_init_action(RESPAWN, bb_default_login_shell, ""); | ||
907 | } else { | ||
908 | niro | 984 | /* Not in single user mode - see what inittab says */ |
909 | niro | 532 | |
910 | /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined, | ||
911 | * then parse_inittab() simply adds in some default | ||
912 | niro | 984 | * actions(i.e., INIT_SCRIPT and a pair |
913 | niro | 532 | * of "askfirst" shells */ |
914 | parse_inittab(); | ||
915 | } | ||
916 | |||
917 | #if ENABLE_SELINUX | ||
918 | if (getenv("SELINUX_INIT") == NULL) { | ||
919 | int enforce = 0; | ||
920 | |||
921 | niro | 816 | putenv((char*)"SELINUX_INIT=YES"); |
922 | niro | 532 | if (selinux_init_load_policy(&enforce) == 0) { |
923 | niro | 816 | BB_EXECVP(argv[0], argv); |
924 | niro | 532 | } else if (enforce > 0) { |
925 | /* SELinux in enforcing mode but load_policy failed */ | ||
926 | niro | 984 | message(L_CONSOLE, "can't load SELinux Policy. " |
927 | niro | 816 | "Machine is in enforcing mode. Halting now."); |
928 | exit(EXIT_FAILURE); | ||
929 | niro | 532 | } |
930 | } | ||
931 | niro | 984 | #endif |
932 | niro | 532 | |
933 | niro | 816 | /* Make the command line just say "init" - thats all, nothing else */ |
934 | strncpy(argv[0], "init", strlen(argv[0])); | ||
935 | /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */ | ||
936 | while (*++argv) | ||
937 | memset(*argv, 0, strlen(*argv)); | ||
938 | niro | 532 | |
939 | niro | 984 | /* Set up signal handlers */ |
940 | if (!DEBUG_INIT) { | ||
941 | struct sigaction sa; | ||
942 | |||
943 | bb_signals(0 | ||
944 | + (1 << SIGUSR1) /* halt */ | ||
945 | + (1 << SIGTERM) /* reboot */ | ||
946 | + (1 << SIGUSR2) /* poweroff */ | ||
947 | , halt_reboot_pwoff); | ||
948 | signal(SIGQUIT, restart_handler); /* re-exec another init */ | ||
949 | |||
950 | /* Stop handler must allow only SIGCONT inside itself */ | ||
951 | memset(&sa, 0, sizeof(sa)); | ||
952 | sigfillset(&sa.sa_mask); | ||
953 | sigdelset(&sa.sa_mask, SIGCONT); | ||
954 | sa.sa_handler = stop_handler; | ||
955 | /* NB: sa_flags doesn't have SA_RESTART. | ||
956 | * It must be able to interrupt wait(). | ||
957 | */ | ||
958 | sigaction_set(SIGTSTP, &sa); /* pause */ | ||
959 | /* Does not work as intended, at least in 2.6.20. | ||
960 | * SIGSTOP is simply ignored by init: | ||
961 | */ | ||
962 | sigaction_set(SIGSTOP, &sa); /* pause */ | ||
963 | |||
964 | /* SIGINT (Ctrl-Alt-Del) must interrupt wait(), | ||
965 | * setting handler without SA_RESTART flag. | ||
966 | */ | ||
967 | bb_signals_recursive_norestart((1 << SIGINT), record_signo); | ||
968 | } | ||
969 | |||
970 | /* Set up "reread /etc/inittab" handler. | ||
971 | * Handler is set up without SA_RESTART, it will interrupt syscalls. | ||
972 | */ | ||
973 | if (!DEBUG_INIT && ENABLE_FEATURE_USE_INITTAB) | ||
974 | bb_signals_recursive_norestart((1 << SIGHUP), record_signo); | ||
975 | |||
976 | niro | 532 | /* Now run everything that needs to be run */ |
977 | /* First run the sysinit command */ | ||
978 | run_actions(SYSINIT); | ||
979 | niro | 984 | check_delayed_sigs(); |
980 | niro | 532 | /* Next run anything that wants to block */ |
981 | run_actions(WAIT); | ||
982 | niro | 984 | check_delayed_sigs(); |
983 | niro | 532 | /* Next run anything to be run only once */ |
984 | run_actions(ONCE); | ||
985 | |||
986 | niro | 984 | /* Now run the looping stuff for the rest of forever. |
987 | */ | ||
988 | while (1) { | ||
989 | int maybe_WNOHANG; | ||
990 | niro | 532 | |
991 | niro | 984 | maybe_WNOHANG = check_delayed_sigs(); |
992 | |||
993 | /* (Re)run the respawn/askfirst stuff */ | ||
994 | niro | 816 | run_actions(RESPAWN | ASKFIRST); |
995 | niro | 984 | maybe_WNOHANG |= check_delayed_sigs(); |
996 | niro | 532 | |
997 | niro | 984 | /* Don't consume all CPU time - sleep a bit */ |
998 | niro | 532 | sleep(1); |
999 | niro | 984 | maybe_WNOHANG |= check_delayed_sigs(); |
1000 | niro | 532 | |
1001 | niro | 984 | /* Wait for any child process(es) to exit. |
1002 | * | ||
1003 | * If check_delayed_sigs above reported that a signal | ||
1004 | * was caught, wait will be nonblocking. This ensures | ||
1005 | * that if SIGHUP has reloaded inittab, respawn and askfirst | ||
1006 | * actions will not be delayed until next child death. | ||
1007 | */ | ||
1008 | if (maybe_WNOHANG) | ||
1009 | maybe_WNOHANG = WNOHANG; | ||
1010 | while (1) { | ||
1011 | pid_t wpid; | ||
1012 | struct init_action *a; | ||
1013 | |||
1014 | /* If signals happen _in_ the wait, they interrupt it, | ||
1015 | * bb_signals_recursive_norestart set them up that way | ||
1016 | */ | ||
1017 | wpid = waitpid(-1, NULL, maybe_WNOHANG); | ||
1018 | if (wpid <= 0) | ||
1019 | break; | ||
1020 | |||
1021 | a = mark_terminated(wpid); | ||
1022 | if (a) { | ||
1023 | message(L_LOG, "process '%s' (pid %d) exited. " | ||
1024 | "Scheduling for restart.", | ||
1025 | a->command, wpid); | ||
1026 | niro | 532 | } |
1027 | niro | 984 | /* See if anyone else is waiting to be reaped */ |
1028 | maybe_WNOHANG = WNOHANG; | ||
1029 | niro | 532 | } |
1030 | niro | 984 | } /* while (1) */ |
1031 | niro | 532 | } |