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-rw-r--r--busybox/init/init.c1214
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diff --git a/busybox/init/init.c b/busybox/init/init.c
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+++ b/busybox/init/init.c
@@ -0,0 +1,1214 @@
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 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 *
23 */
24
25/* Turn this on to disable all the dangerous
26 rebooting stuff when debugging.
27#define DEBUG_INIT
28*/
29
30#include <stdio.h>
31#include <stdlib.h>
32#include <errno.h>
33#include <paths.h>
34#include <signal.h>
35#include <stdarg.h>
36#include <string.h>
37#include <termios.h>
38#include <unistd.h>
39#include <limits.h>
40#include <sys/fcntl.h>
41#include <sys/ioctl.h>
42#include <sys/mount.h>
43#include <sys/types.h>
44#include <sys/wait.h>
45#include <sys/reboot.h>
46#include "busybox.h"
47
48#include "init_shared.h"
49
50
51#ifdef CONFIG_SYSLOGD
52# include <sys/syslog.h>
53#endif
54
55
56#define INIT_BUFFS_SIZE 256
57
58/* From <linux/vt.h> */
59struct vt_stat {
60 unsigned short v_active; /* active vt */
61 unsigned short v_signal; /* signal to send */
62 unsigned short v_state; /* vt bitmask */
63};
64static const int VT_GETSTATE = 0x5603; /* get global vt state info */
65
66/* From <linux/serial.h> */
67struct serial_struct {
68 int type;
69 int line;
70 unsigned int port;
71 int irq;
72 int flags;
73 int xmit_fifo_size;
74 int custom_divisor;
75 int baud_base;
76 unsigned short close_delay;
77 char io_type;
78 char reserved_char[1];
79 int hub6;
80 unsigned short closing_wait; /* time to wait before closing */
81 unsigned short closing_wait2; /* no longer used... */
82 unsigned char *iomem_base;
83 unsigned short iomem_reg_shift;
84 unsigned int port_high;
85 unsigned long iomap_base; /* cookie passed into ioremap */
86 int reserved[1];
87};
88
89
90#ifndef _PATH_STDPATH
91#define _PATH_STDPATH "/usr/bin:/bin:/usr/sbin:/sbin"
92#endif
93
94#if defined CONFIG_FEATURE_INIT_COREDUMPS
95/*
96 * When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
97 * before processes are spawned to set core file size as unlimited.
98 * This is for debugging only. Don't use this is production, unless
99 * you want core dumps lying about....
100 */
101#define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
102#include <sys/resource.h>
103#include <sys/time.h>
104#endif
105
106#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
107
108#define INITTAB "/etc/inittab" /* inittab file location */
109#ifndef INIT_SCRIPT
110#define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
111#endif
112
113#define MAXENV 16 /* Number of env. vars */
114
115#define CONSOLE_BUFF_SIZE 32
116
117/* Allowed init action types */
118#define SYSINIT 0x001
119#define RESPAWN 0x002
120#define ASKFIRST 0x004
121#define WAIT 0x008
122#define ONCE 0x010
123#define CTRLALTDEL 0x020
124#define SHUTDOWN 0x040
125#define RESTART 0x080
126
127/* A mapping between "inittab" action name strings and action type codes. */
128struct init_action_type {
129 const char *name;
130 int action;
131};
132
133static const struct init_action_type actions[] = {
134 {"sysinit", SYSINIT},
135 {"respawn", RESPAWN},
136 {"askfirst", ASKFIRST},
137 {"wait", WAIT},
138 {"once", ONCE},
139 {"ctrlaltdel", CTRLALTDEL},
140 {"shutdown", SHUTDOWN},
141 {"restart", RESTART},
142 {0, 0}
143};
144
145/* Set up a linked list of init_actions, to be read from inittab */
146struct init_action {
147 pid_t pid;
148 char command[INIT_BUFFS_SIZE];
149 char terminal[CONSOLE_BUFF_SIZE];
150 struct init_action *next;
151 int action;
152};
153
154/* Static variables */
155static struct init_action *init_action_list = NULL;
156static char console[CONSOLE_BUFF_SIZE] = _PATH_CONSOLE;
157
158#ifndef CONFIG_SYSLOGD
159static char *log = VC_5;
160#endif
161static sig_atomic_t got_cont = 0;
162static const int LOG = 0x1;
163static const int CONSOLE = 0x2;
164
165#if defined CONFIG_FEATURE_EXTRA_QUIET
166static const int MAYBE_CONSOLE = 0x0;
167#else
168#define MAYBE_CONSOLE CONSOLE
169#endif
170#ifndef RB_HALT_SYSTEM
171static const int RB_HALT_SYSTEM = 0xcdef0123;
172static const int RB_ENABLE_CAD = 0x89abcdef;
173static const int RB_DISABLE_CAD = 0;
174
175#define RB_POWER_OFF 0x4321fedc
176static const int RB_AUTOBOOT = 0x01234567;
177#endif
178
179static const char * const environment[] = {
180 "HOME=/",
181 "PATH=" _PATH_STDPATH,
182 "SHELL=/bin/sh",
183 "USER=root",
184 NULL
185};
186
187/* Function prototypes */
188static void delete_init_action(struct init_action *a);
189static int waitfor(const struct init_action *a);
190static void halt_signal(int sig);
191
192
193static void loop_forever(void)
194{
195 while (1)
196 sleep(1);
197}
198
199/* Print a message to the specified device.
200 * Device may be bitwise-or'd from LOG | CONSOLE */
201#ifndef DEBUG_INIT
202static inline void messageD(int device, const char *fmt, ...)
203{
204}
205#else
206#define messageD message
207#endif
208static void message(int device, const char *fmt, ...)
209 __attribute__ ((format(printf, 2, 3)));
210static void message(int device, const char *fmt, ...)
211{
212 va_list arguments;
213 int l;
214 char msg[1024];
215#ifndef CONFIG_SYSLOGD
216 static int log_fd = -1;
217#endif
218
219 msg[0] = '\r';
220 va_start(arguments, fmt);
221 l = vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments) + 1;
222 va_end(arguments);
223
224#ifdef CONFIG_SYSLOGD
225 /* Log the message to syslogd */
226 if (device & LOG) {
227 /* don`t out "\r\n" */
228 openlog(bb_applet_name, 0, LOG_DAEMON);
229 syslog(LOG_INFO, "%s", msg);
230 closelog();
231 }
232
233 msg[l++] = '\n';
234 msg[l] = 0;
235#else
236
237 msg[l++] = '\n';
238 msg[l] = 0;
239 /* Take full control of the log tty, and never close it.
240 * It's mine, all mine! Muhahahaha! */
241 if (log_fd < 0) {
242 if ((log_fd = device_open(log, O_RDWR | O_NDELAY | O_NOCTTY)) < 0) {
243 log_fd = -2;
244 bb_error_msg("Bummer, can't write to log on %s!", log);
245 device = CONSOLE;
246 } else {
247 fcntl(log_fd, F_SETFD, FD_CLOEXEC);
248 }
249 }
250 if ((device & LOG) && (log_fd >= 0)) {
251 bb_full_write(log_fd, msg, l);
252 }
253#endif
254
255 if (device & CONSOLE) {
256 int fd = device_open(_PATH_CONSOLE,
257 O_WRONLY | O_NOCTTY | O_NDELAY);
258 /* Always send console messages to /dev/console so people will see them. */
259 if (fd >= 0) {
260 bb_full_write(fd, msg, l);
261 close(fd);
262#ifdef DEBUG_INIT
263 /* all descriptors may be closed */
264 } else {
265 bb_error_msg("Bummer, can't print: ");
266 va_start(arguments, fmt);
267 vfprintf(stderr, fmt, arguments);
268 va_end(arguments);
269#endif
270 }
271 }
272}
273
274/* Set terminal settings to reasonable defaults */
275static void set_term(int fd)
276{
277 struct termios tty;
278
279 tcgetattr(fd, &tty);
280
281 /* set control chars */
282 tty.c_cc[VINTR] = 3; /* C-c */
283 tty.c_cc[VQUIT] = 28; /* C-\ */
284 tty.c_cc[VERASE] = 127; /* C-? */
285 tty.c_cc[VKILL] = 21; /* C-u */
286 tty.c_cc[VEOF] = 4; /* C-d */
287 tty.c_cc[VSTART] = 17; /* C-q */
288 tty.c_cc[VSTOP] = 19; /* C-s */
289 tty.c_cc[VSUSP] = 26; /* C-z */
290
291 /* use line dicipline 0 */
292 tty.c_line = 0;
293
294 /* Make it be sane */
295 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
296 tty.c_cflag |= CREAD | HUPCL | CLOCAL;
297
298
299 /* input modes */
300 tty.c_iflag = ICRNL | IXON | IXOFF;
301
302 /* output modes */
303 tty.c_oflag = OPOST | ONLCR;
304
305 /* local modes */
306 tty.c_lflag =
307 ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
308
309 tcsetattr(fd, TCSANOW, &tty);
310}
311
312/* How much memory does this machine have?
313 Units are kBytes to avoid overflow on 4GB machines */
314static unsigned int check_free_memory(void)
315{
316 struct sysinfo info;
317 unsigned int result, u, s = 10;
318
319 if (sysinfo(&info) != 0) {
320 bb_perror_msg("Error checking free memory");
321 return -1;
322 }
323
324 /* Kernels 2.0.x and 2.2.x return info.mem_unit==0 with values in bytes.
325 * Kernels 2.4.0 return info.mem_unit in bytes. */
326 u = info.mem_unit;
327 if (u == 0)
328 u = 1;
329 while ((u & 1) == 0 && s > 0) {
330 u >>= 1;
331 s--;
332 }
333 result = (info.totalram >> s) + (info.totalswap >> s);
334 if (((unsigned long long)result * (unsigned long long)u) > UINT_MAX) {
335 return(UINT_MAX);
336 } else {
337 return(result * u);
338 }
339}
340
341static void console_init(void)
342{
343 int fd;
344 int tried = 0;
345 struct vt_stat vt;
346 struct serial_struct sr;
347 char *s;
348
349 if ((s = getenv("CONSOLE")) != NULL || (s = getenv("console")) != NULL) {
350 safe_strncpy(console, s, sizeof(console));
351#if #cpu(sparc)
352 /* sparc kernel supports console=tty[ab] parameter which is also
353 * passed to init, so catch it here */
354 /* remap tty[ab] to /dev/ttyS[01] */
355 if (strcmp(s, "ttya") == 0)
356 safe_strncpy(console, SC_0, sizeof(console));
357 else if (strcmp(s, "ttyb") == 0)
358 safe_strncpy(console, SC_1, sizeof(console));
359#endif
360 } else {
361 /* 2.2 kernels: identify the real console backend and try to use it */
362 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
363 /* this is a serial console */
364 snprintf(console, sizeof(console) - 1, SC_FORMAT, sr.line);
365 } else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
366 /* this is linux virtual tty */
367 snprintf(console, sizeof(console) - 1, VC_FORMAT, vt.v_active);
368 } else {
369 safe_strncpy(console, _PATH_CONSOLE, sizeof(console));
370 tried++;
371 }
372 }
373
374 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0 && tried < 2) {
375 /* Can't open selected console -- try
376 logical system console and VT_MASTER */
377 safe_strncpy(console, (tried == 0 ? _PATH_CONSOLE : CURRENT_VC),
378 sizeof(console));
379 tried++;
380 }
381 if (fd < 0) {
382 /* Perhaps we should panic here? */
383#ifndef CONFIG_SYSLOGD
384 log =
385#endif
386 safe_strncpy(console, "/dev/null", sizeof(console));
387 } else {
388 s = getenv("TERM");
389 /* check for serial console */
390 if (ioctl(fd, TIOCGSERIAL, &sr) == 0) {
391 /* Force the TERM setting to vt102 for serial console --
392 * if TERM is set to linux (the default) */
393 if (s == NULL || strcmp(s, "linux") == 0)
394 putenv("TERM=vt102");
395#ifndef CONFIG_SYSLOGD
396 log = console;
397#endif
398 } else {
399 if (s == NULL)
400 putenv("TERM=linux");
401 }
402 close(fd);
403 }
404 messageD(LOG, "console=%s", console);
405}
406
407static void fixup_argv(int argc, char **argv, char *new_argv0)
408{
409 int len;
410
411 /* Fix up argv[0] to be certain we claim to be init */
412 len = strlen(argv[0]);
413 memset(argv[0], 0, len);
414 safe_strncpy(argv[0], new_argv0, len + 1);
415
416 /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
417 len = 1;
418 while (argc > len) {
419 memset(argv[len], 0, strlen(argv[len]));
420 len++;
421 }
422}
423
424static pid_t run(const struct init_action *a)
425{
426 struct stat sb;
427 int i, junk;
428 pid_t pid, pgrp, tmp_pid;
429 char *s, *tmpCmd, *cmd[INIT_BUFFS_SIZE], *cmdpath;
430 char buf[INIT_BUFFS_SIZE + 6]; /* INIT_BUFFS_SIZE+strlen("exec ")+1 */
431 sigset_t nmask, omask;
432 static const char press_enter[] =
433#ifdef CUSTOMIZED_BANNER
434#include CUSTOMIZED_BANNER
435#endif
436 "\nPlease press Enter to activate this console. ";
437
438 /* Block sigchild while forking. */
439 sigemptyset(&nmask);
440 sigaddset(&nmask, SIGCHLD);
441 sigprocmask(SIG_BLOCK, &nmask, &omask);
442
443 if ((pid = fork()) == 0) {
444 /* Clean up */
445 close(0);
446 close(1);
447 close(2);
448 sigprocmask(SIG_SETMASK, &omask, NULL);
449
450 /* Reset signal handlers that were set by the parent process */
451 signal(SIGUSR1, SIG_DFL);
452 signal(SIGUSR2, SIG_DFL);
453 signal(SIGINT, SIG_DFL);
454 signal(SIGTERM, SIG_DFL);
455 signal(SIGHUP, SIG_DFL);
456 signal(SIGCONT, SIG_DFL);
457 signal(SIGSTOP, SIG_DFL);
458 signal(SIGTSTP, SIG_DFL);
459
460 /* Create a new session and make ourself the process
461 * group leader */
462 setsid();
463
464 /* Open the new terminal device */
465 if ((device_open(a->terminal, O_RDWR)) < 0) {
466 if (stat(a->terminal, &sb) != 0) {
467 message(LOG | CONSOLE, "device '%s' does not exist.",
468 a->terminal);
469 _exit(1);
470 }
471 message(LOG | CONSOLE, "Bummer, can't open %s", a->terminal);
472 _exit(1);
473 }
474
475 /* Make sure the terminal will act fairly normal for us */
476 set_term(0);
477 /* Setup stdout, stderr for the new process so
478 * they point to the supplied terminal */
479 dup(0);
480 dup(0);
481
482 /* If the init Action requires us to wait, then force the
483 * supplied terminal to be the controlling tty. */
484 if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
485
486 /* Now fork off another process to just hang around */
487 if ((pid = fork()) < 0) {
488 message(LOG | CONSOLE, "Can't fork!");
489 _exit(1);
490 }
491
492 if (pid > 0) {
493
494 /* We are the parent -- wait till the child is done */
495 signal(SIGINT, SIG_IGN);
496 signal(SIGTSTP, SIG_IGN);
497 signal(SIGQUIT, SIG_IGN);
498 signal(SIGCHLD, SIG_DFL);
499
500 /* Wait for child to exit */
501 while ((tmp_pid = waitpid(pid, &junk, 0)) != pid) {
502 if (tmp_pid == -1 && errno == ECHILD) {
503 break;
504 }
505 /* FIXME handle other errors */
506 }
507
508 /* See if stealing the controlling tty back is necessary */
509 pgrp = tcgetpgrp(0);
510 if (pgrp != getpid())
511 _exit(0);
512
513 /* Use a temporary process to steal the controlling tty. */
514 if ((pid = fork()) < 0) {
515 message(LOG | CONSOLE, "Can't fork!");
516 _exit(1);
517 }
518 if (pid == 0) {
519 setsid();
520 ioctl(0, TIOCSCTTY, 1);
521 _exit(0);
522 }
523 while ((tmp_pid = waitpid(pid, &junk, 0)) != pid) {
524 if (tmp_pid < 0 && errno == ECHILD)
525 break;
526 }
527 _exit(0);
528 }
529
530 /* Now fall though to actually execute things */
531 }
532
533 /* See if any special /bin/sh requiring characters are present */
534 if (strpbrk(a->command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
535 cmd[0] = (char *)DEFAULT_SHELL;
536 cmd[1] = "-c";
537 cmd[2] = strcat(strcpy(buf, "exec "), a->command);
538 cmd[3] = NULL;
539 } else {
540 /* Convert command (char*) into cmd (char**, one word per string) */
541 strcpy(buf, a->command);
542 s = buf;
543 for (tmpCmd = buf, i = 0; (tmpCmd = strsep(&s, " \t")) != NULL;) {
544 if (*tmpCmd != '\0') {
545 cmd[i] = tmpCmd;
546 i++;
547 }
548 }
549 cmd[i] = NULL;
550 }
551
552 cmdpath = cmd[0];
553
554 /*
555 Interactive shells want to see a dash in argv[0]. This
556 typically is handled by login, argv will be setup this
557 way if a dash appears at the front of the command path
558 (like "-/bin/sh").
559 */
560
561 if (*cmdpath == '-') {
562
563 /* skip over the dash */
564 ++cmdpath;
565
566 /* find the last component in the command pathname */
567 s = bb_get_last_path_component(cmdpath);
568
569 /* make a new argv[0] */
570 if ((cmd[0] = malloc(strlen(s) + 2)) == NULL) {
571 message(LOG | CONSOLE, bb_msg_memory_exhausted);
572 cmd[0] = cmdpath;
573 } else {
574 cmd[0][0] = '-';
575 strcpy(cmd[0] + 1, s);
576 }
577 }
578
579#if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
580 if (a->action & ASKFIRST) {
581 char c;
582 /*
583 * Save memory by not exec-ing anything large (like a shell)
584 * before the user wants it. This is critical if swap is not
585 * enabled and the system has low memory. Generally this will
586 * be run on the second virtual console, and the first will
587 * be allowed to start a shell or whatever an init script
588 * specifies.
589 */
590 messageD(LOG, "Waiting for enter to start '%s'"
591 "(pid %d, terminal %s)\n",
592 cmdpath, getpid(), a->terminal);
593 bb_full_write(1, press_enter, sizeof(press_enter) - 1);
594 while(read(0, &c, 1) == 1 && c != '\n')
595 ;
596 }
597#endif
598
599 /* Log the process name and args */
600 message(LOG, "Starting pid %d, console %s: '%s'",
601 getpid(), a->terminal, cmdpath);
602
603#if defined CONFIG_FEATURE_INIT_COREDUMPS
604 if (stat(CORE_ENABLE_FLAG_FILE, &sb) == 0) {
605 struct rlimit limit;
606
607 limit.rlim_cur = RLIM_INFINITY;
608 limit.rlim_max = RLIM_INFINITY;
609 setrlimit(RLIMIT_CORE, &limit);
610 }
611#endif
612
613 /* Now run it. The new program will take over this PID,
614 * so nothing further in init.c should be run. */
615 execv(cmdpath, cmd);
616
617 /* We're still here? Some error happened. */
618 message(LOG | CONSOLE, "Bummer, could not run '%s': %m", cmdpath);
619 _exit(-1);
620 }
621 sigprocmask(SIG_SETMASK, &omask, NULL);
622 return pid;
623}
624
625static int waitfor(const struct init_action *a)
626{
627 int pid;
628 int status, wpid;
629
630 pid = run(a);
631 while (1) {
632 wpid = waitpid(pid,&status,0);
633 if (wpid == pid)
634 break;
635 if (wpid == -1 && errno == ECHILD) {
636 /* we missed its termination */
637 break;
638 }
639 /* FIXME other errors should maybe trigger an error, but allow
640 * the program to continue */
641 }
642 return wpid;
643}
644
645/* Run all commands of a particular type */
646static void run_actions(int action)
647{
648 struct init_action *a, *tmp;
649
650 for (a = init_action_list; a; a = tmp) {
651 tmp = a->next;
652 if (a->action == action) {
653 if (a->action & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
654 waitfor(a);
655 delete_init_action(a);
656 } else if (a->action & ONCE) {
657 run(a);
658 delete_init_action(a);
659 } else if (a->action & (RESPAWN | ASKFIRST)) {
660 /* Only run stuff with pid==0. If they have
661 * a pid, that means it is still running */
662 if (a->pid == 0) {
663 a->pid = run(a);
664 }
665 }
666 }
667 }
668}
669
670#ifndef DEBUG_INIT
671static void init_reboot(unsigned long magic)
672{
673 pid_t pid;
674 /* We have to fork here, since the kernel calls do_exit(0) in
675 * linux/kernel/sys.c, which can cause the machine to panic when
676 * the init process is killed.... */
677 if ((pid = fork()) == 0) {
678 reboot(magic);
679 _exit(0);
680 }
681 waitpid (pid, NULL, 0);
682}
683
684static void shutdown_system(void)
685{
686 sigset_t block_signals;
687
688 /* run everything to be run at "shutdown". This is done _prior_
689 * to killing everything, in case people wish to use scripts to
690 * shut things down gracefully... */
691 run_actions(SHUTDOWN);
692
693 /* first disable all our signals */
694 sigemptyset(&block_signals);
695 sigaddset(&block_signals, SIGHUP);
696 sigaddset(&block_signals, SIGCHLD);
697 sigaddset(&block_signals, SIGUSR1);
698 sigaddset(&block_signals, SIGUSR2);
699 sigaddset(&block_signals, SIGINT);
700 sigaddset(&block_signals, SIGTERM);
701 sigaddset(&block_signals, SIGCONT);
702 sigaddset(&block_signals, SIGSTOP);
703 sigaddset(&block_signals, SIGTSTP);
704 sigprocmask(SIG_BLOCK, &block_signals, NULL);
705
706 /* Allow Ctrl-Alt-Del to reboot system. */
707 init_reboot(RB_ENABLE_CAD);
708
709 message(CONSOLE | LOG, "The system is going down NOW !!");
710 sync();
711
712 /* Send signals to every process _except_ pid 1 */
713 message(CONSOLE | LOG, "Sending SIGTERM to all processes.");
714 kill(-1, SIGTERM);
715 sleep(1);
716 sync();
717
718 message(CONSOLE | LOG, "Sending SIGKILL to all processes.");
719 kill(-1, SIGKILL);
720 sleep(1);
721
722 sync();
723}
724
725static void exec_signal(int sig)
726{
727 struct init_action *a, *tmp;
728 sigset_t unblock_signals;
729
730 for (a = init_action_list; a; a = tmp) {
731 tmp = a->next;
732 if (a->action & RESTART) {
733 struct stat sb;
734
735 shutdown_system();
736
737 /* unblock all signals, blocked in shutdown_system() */
738 sigemptyset(&unblock_signals);
739 sigaddset(&unblock_signals, SIGHUP);
740 sigaddset(&unblock_signals, SIGCHLD);
741 sigaddset(&unblock_signals, SIGUSR1);
742 sigaddset(&unblock_signals, SIGUSR2);
743 sigaddset(&unblock_signals, SIGINT);
744 sigaddset(&unblock_signals, SIGTERM);
745 sigaddset(&unblock_signals, SIGCONT);
746 sigaddset(&unblock_signals, SIGSTOP);
747 sigaddset(&unblock_signals, SIGTSTP);
748 sigprocmask(SIG_UNBLOCK, &unblock_signals, NULL);
749
750 /* Close whatever files are open. */
751 close(0);
752 close(1);
753 close(2);
754
755 /* Open the new terminal device */
756 if ((device_open(a->terminal, O_RDWR)) < 0) {
757 if (stat(a->terminal, &sb) != 0) {
758 message(LOG | CONSOLE, "device '%s' does not exist.", a->terminal);
759 } else {
760 message(LOG | CONSOLE, "Bummer, can't open %s", a->terminal);
761 }
762 halt_signal(SIGUSR1);
763 }
764
765 /* Make sure the terminal will act fairly normal for us */
766 set_term(0);
767 /* Setup stdout, stderr on the supplied terminal */
768 dup(0);
769 dup(0);
770
771 messageD(CONSOLE | LOG, "Trying to re-exec %s", a->command);
772 execl(a->command, a->command, NULL);
773
774 message(CONSOLE | LOG, "exec of '%s' failed: %m",
775 a->command);
776 sync();
777 sleep(2);
778 init_reboot(RB_HALT_SYSTEM);
779 loop_forever();
780 }
781 }
782}
783
784static void halt_signal(int sig)
785{
786 shutdown_system();
787 message(CONSOLE | LOG,
788#if #cpu(s390)
789 /* Seems the s390 console is Wierd(tm). */
790 "The system is halted. You may reboot now."
791#else
792 "The system is halted. Press Reset or turn off power"
793#endif
794 );
795 sync();
796
797 /* allow time for last message to reach serial console */
798 sleep(2);
799
800 if (sig == SIGUSR2)
801 init_reboot(RB_POWER_OFF);
802 else
803 init_reboot(RB_HALT_SYSTEM);
804
805 loop_forever();
806}
807
808static void reboot_signal(int sig)
809{
810 shutdown_system();
811 message(CONSOLE | LOG, "Please stand by while rebooting the system.");
812 sync();
813
814 /* allow time for last message to reach serial console */
815 sleep(2);
816
817 init_reboot(RB_AUTOBOOT);
818
819 loop_forever();
820}
821
822static void ctrlaltdel_signal(int sig)
823{
824 run_actions(CTRLALTDEL);
825}
826
827/* The SIGSTOP & SIGTSTP handler */
828static void stop_handler(int sig)
829{
830 int saved_errno = errno;
831
832 got_cont = 0;
833 while (!got_cont)
834 pause();
835 got_cont = 0;
836 errno = saved_errno;
837}
838
839/* The SIGCONT handler */
840static void cont_handler(int sig)
841{
842 got_cont = 1;
843}
844
845#endif /* ! DEBUG_INIT */
846
847static void new_init_action(int action, const char *command, const char *cons)
848{
849 struct init_action *new_action, *a, *last;
850
851 if (*cons == '\0')
852 cons = console;
853
854 /* do not run entries if console device is not available */
855 if (access(cons, R_OK | W_OK))
856 return;
857 if (strcmp(cons, "/dev/null") == 0 && (action & ASKFIRST))
858 return;
859
860 new_action = calloc((size_t) (1), sizeof(struct init_action));
861 if (!new_action) {
862 message(LOG | CONSOLE, "Memory allocation failure");
863 loop_forever();
864 }
865
866 /* Append to the end of the list */
867 for (a = last = init_action_list; a; a = a->next) {
868 /* don't enter action if it's already in the list,
869 * but do overwrite existing actions */
870 if ((strcmp(a->command, command) == 0) &&
871 (strcmp(a->terminal, cons) ==0)) {
872 a->action = action;
873 free(new_action);
874 return;
875 }
876 last = a;
877 }
878 if (last) {
879 last->next = new_action;
880 } else {
881 init_action_list = new_action;
882 }
883 strcpy(new_action->command, command);
884 new_action->action = action;
885 strcpy(new_action->terminal, cons);
886#if 0 /* calloc zeroed always */
887 new_action->pid = 0;
888#endif
889 messageD(LOG|CONSOLE, "command='%s' action='%d' terminal='%s'\n",
890 new_action->command, new_action->action, new_action->terminal);
891}
892
893static void delete_init_action(struct init_action *action)
894{
895 struct init_action *a, *b = NULL;
896
897 for (a = init_action_list; a; b = a, a = a->next) {
898 if (a == action) {
899 if (b == NULL) {
900 init_action_list = a->next;
901 } else {
902 b->next = a->next;
903 }
904 free(a);
905 break;
906 }
907 }
908}
909
910/* Make sure there is enough memory to do something useful. *
911 * Calls "swapon -a" if needed so be sure /etc/fstab is present... */
912static void check_memory(void)
913{
914 struct stat statBuf;
915
916 if (check_free_memory() > 1000)
917 return;
918
919#if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
920 if (stat("/etc/fstab", &statBuf) == 0) {
921 /* swapon -a requires /proc typically */
922 new_init_action(SYSINIT, "/bin/mount -t proc proc /proc", "");
923 /* Try to turn on swap */
924 new_init_action(SYSINIT, "/sbin/swapon -a", "");
925 run_actions(SYSINIT); /* wait and removing */
926 if (check_free_memory() < 1000)
927 goto goodnight;
928 } else
929 goto goodnight;
930 return;
931#endif
932
933 goodnight:
934 message(CONSOLE, "Sorry, your computer does not have enough memory.");
935 loop_forever();
936}
937
938/* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
939 * then parse_inittab() simply adds in some default
940 * actions(i.e., runs INIT_SCRIPT and then starts a pair
941 * of "askfirst" shells). If CONFIG_FEATURE_USE_INITTAB
942 * _is_ defined, but /etc/inittab is missing, this
943 * results in the same set of default behaviors.
944 */
945static void parse_inittab(void)
946{
947#ifdef CONFIG_FEATURE_USE_INITTAB
948 FILE *file;
949 char buf[INIT_BUFFS_SIZE], lineAsRead[INIT_BUFFS_SIZE];
950 char tmpConsole[CONSOLE_BUFF_SIZE];
951 char *id, *runlev, *action, *command, *eol;
952 const struct init_action_type *a = actions;
953
954
955 file = fopen(INITTAB, "r");
956 if (file == NULL) {
957 /* No inittab file -- set up some default behavior */
958#endif
959 /* Reboot on Ctrl-Alt-Del */
960 new_init_action(CTRLALTDEL, "/sbin/reboot", "");
961 /* Umount all filesystems on halt/reboot */
962 new_init_action(SHUTDOWN, "/bin/umount -a -r", "");
963#if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
964 /* Swapoff on halt/reboot */
965 new_init_action(SHUTDOWN, "/sbin/swapoff -a", "");
966#endif
967 /* Prepare to restart init when a HUP is received */
968 new_init_action(RESTART, "/sbin/init", "");
969 /* Askfirst shell on tty1-4 */
970 new_init_action(ASKFIRST, bb_default_login_shell, "");
971 new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
972 new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
973 new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
974 /* sysinit */
975 new_init_action(SYSINIT, INIT_SCRIPT, "");
976
977 return;
978#ifdef CONFIG_FEATURE_USE_INITTAB
979 }
980
981 while (fgets(buf, INIT_BUFFS_SIZE, file) != NULL) {
982 /* Skip leading spaces */
983 for (id = buf; *id == ' ' || *id == '\t'; id++);
984
985 /* Skip the line if it's a comment */
986 if (*id == '#' || *id == '\n')
987 continue;
988
989 /* Trim the trailing \n */
990 eol = strrchr(id, '\n');
991 if (eol != NULL)
992 *eol = '\0';
993
994 /* Keep a copy around for posterity's sake (and error msgs) */
995 strcpy(lineAsRead, buf);
996
997 /* Separate the ID field from the runlevels */
998 runlev = strchr(id, ':');
999 if (runlev == NULL || *(runlev + 1) == '\0') {
1000 message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
1001 continue;
1002 } else {
1003 *runlev = '\0';
1004 ++runlev;
1005 }
1006
1007 /* Separate the runlevels from the action */
1008 action = strchr(runlev, ':');
1009 if (action == NULL || *(action + 1) == '\0') {
1010 message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
1011 continue;
1012 } else {
1013 *action = '\0';
1014 ++action;
1015 }
1016
1017 /* Separate the action from the command */
1018 command = strchr(action, ':');
1019 if (command == NULL || *(command + 1) == '\0') {
1020 message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
1021 continue;
1022 } else {
1023 *command = '\0';
1024 ++command;
1025 }
1026
1027 /* Ok, now process it */
1028 for (a = actions; a->name != 0; a++) {
1029 if (strcmp(a->name, action) == 0) {
1030 if (*id != '\0') {
1031 if(strncmp(id, "/dev/", 5) == 0)
1032 id += 5;
1033 strcpy(tmpConsole, "/dev/");
1034 safe_strncpy(tmpConsole + 5, id,
1035 CONSOLE_BUFF_SIZE - 5);
1036 id = tmpConsole;
1037 }
1038 new_init_action(a->action, command, id);
1039 break;
1040 }
1041 }
1042 if (a->name == 0) {
1043 /* Choke on an unknown action */
1044 message(LOG | CONSOLE, "Bad inittab entry: %s", lineAsRead);
1045 }
1046 }
1047 fclose(file);
1048 return;
1049#endif /* CONFIG_FEATURE_USE_INITTAB */
1050}
1051
1052#ifdef CONFIG_FEATURE_USE_INITTAB
1053static void reload_signal(int sig)
1054{
1055 struct init_action *a, *tmp;
1056
1057 message(LOG, "Reloading /etc/inittab");
1058
1059 /* disable old entrys */
1060 for (a = init_action_list; a; a = a->next ) {
1061 a->action = ONCE;
1062 }
1063
1064 parse_inittab();
1065
1066 /* remove unused entrys */
1067 for (a = init_action_list; a; a = tmp) {
1068 tmp = a->next;
1069 if (a->action & (ONCE | SYSINIT | WAIT ) &&
1070 a->pid == 0 ) {
1071 delete_init_action(a);
1072 }
1073 }
1074 run_actions(RESPAWN);
1075 return;
1076}
1077#endif /* CONFIG_FEATURE_USE_INITTAB */
1078
1079extern int init_main(int argc, char **argv)
1080{
1081 struct init_action *a;
1082 pid_t wpid;
1083 int status;
1084
1085 if (argc > 1 && !strcmp(argv[1], "-q")) {
1086 return kill_init(SIGHUP);
1087 }
1088#ifndef DEBUG_INIT
1089 /* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
1090 if (getpid() != 1
1091#ifdef CONFIG_FEATURE_INITRD
1092 && strstr(bb_applet_name, "linuxrc") == NULL
1093#endif
1094 ) {
1095 bb_show_usage();
1096 }
1097 /* Set up sig handlers -- be sure to
1098 * clear all of these in run() */
1099 signal(SIGHUP, exec_signal);
1100 signal(SIGUSR1, halt_signal);
1101 signal(SIGUSR2, halt_signal);
1102 signal(SIGINT, ctrlaltdel_signal);
1103 signal(SIGTERM, reboot_signal);
1104 signal(SIGCONT, cont_handler);
1105 signal(SIGSTOP, stop_handler);
1106 signal(SIGTSTP, stop_handler);
1107
1108 /* Turn off rebooting via CTL-ALT-DEL -- we get a
1109 * SIGINT on CAD so we can shut things down gracefully... */
1110 init_reboot(RB_DISABLE_CAD);
1111#endif
1112
1113 /* Figure out where the default console should be */
1114 console_init();
1115
1116 /* Close whatever files are open, and reset the console. */
1117 close(0);
1118 close(1);
1119 close(2);
1120
1121 if (device_open(console, O_RDWR | O_NOCTTY) == 0) {
1122 set_term(0);
1123 close(0);
1124 }
1125
1126 chdir("/");
1127 setsid();
1128 {
1129 const char * const *e;
1130 /* Make sure environs is set to something sane */
1131 for(e = environment; *e; e++)
1132 putenv((char *) *e);
1133 }
1134 /* Hello world */
1135 message(MAYBE_CONSOLE | LOG, "init started: %s", bb_msg_full_version);
1136
1137 /* Make sure there is enough memory to do something useful. */
1138 check_memory();
1139
1140 /* Check if we are supposed to be in single user mode */
1141 if (argc > 1 && (!strcmp(argv[1], "single") ||
1142 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
1143 /* Start a shell on console */
1144 new_init_action(RESPAWN, bb_default_login_shell, "");
1145 } else {
1146 /* Not in single user mode -- see what inittab says */
1147
1148 /* NOTE that if CONFIG_FEATURE_USE_INITTAB is NOT defined,
1149 * then parse_inittab() simply adds in some default
1150 * actions(i.e., runs INIT_SCRIPT and then starts a pair
1151 * of "askfirst" shells */
1152 parse_inittab();
1153 }
1154
1155 /* Make the command line just say "init" -- thats all, nothing else */
1156 fixup_argv(argc, argv, "init");
1157
1158 /* Now run everything that needs to be run */
1159
1160 /* First run the sysinit command */
1161 run_actions(SYSINIT);
1162
1163 /* Next run anything that wants to block */
1164 run_actions(WAIT);
1165
1166 /* Next run anything to be run only once */
1167 run_actions(ONCE);
1168
1169#ifdef CONFIG_FEATURE_USE_INITTAB
1170 /* Redefine SIGHUP to reread /etc/inittab */
1171 signal(SIGHUP, reload_signal);
1172#else
1173 signal(SIGHUP, SIG_IGN);
1174#endif /* CONFIG_FEATURE_USE_INITTAB */
1175
1176
1177 /* Now run the looping stuff for the rest of forever */
1178 while (1) {
1179 /* run the respawn stuff */
1180 run_actions(RESPAWN);
1181
1182 /* run the askfirst stuff */
1183 run_actions(ASKFIRST);
1184
1185 /* Don't consume all CPU time -- sleep a bit */
1186 sleep(1);
1187
1188 /* Wait for a child process to exit */
1189 wpid = wait(&status);
1190 while (wpid > 0) {
1191 /* Find out who died and clean up their corpse */
1192 for (a = init_action_list; a; a = a->next) {
1193 if (a->pid == wpid) {
1194 /* Set the pid to 0 so that the process gets
1195 * restarted by run_actions() */
1196 a->pid = 0;
1197 message(LOG, "Process '%s' (pid %d) exited. "
1198 "Scheduling it for restart.",
1199 a->command, wpid);
1200 }
1201 }
1202 /* see if anyone else is waiting to be reaped */
1203 wpid = waitpid (-1, &status, WNOHANG);
1204 }
1205 }
1206}
1207
1208/*
1209Local Variables:
1210c-file-style: "linux"
1211c-basic-offset: 4
1212tab-width: 4
1213End:
1214*/
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-08-14 13:48:54 +0000