2 * Mini init implementation for busybox
5 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
6 * Adjusted by so many folks, it's impossible to keep track.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
32 #include <sys/types.h>
33 #include <sys/fcntl.h>
36 #include <sys/mount.h>
37 #include <sys/reboot.h>
38 #include <sys/kdaemon.h>
39 #include <sys/sysmacros.h>
40 #include <linux/serial.h> /* for serial_struct */
41 #include <sys/vt.h> /* for vt_stat */
42 #include <sys/ioctl.h>
44 #define DEV_CONSOLE "/dev/console" /* Logical system console */
45 #define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
46 #define VT_SECONDARY "/dev/tty2" /* Virtual console */
47 #define VT_LOG "/dev/tty3" /* Virtual console */
48 #define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
49 #define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
50 #define SHELL "/bin/sh" /* Default shell */
51 #define INITSCRIPT "/etc/init.d/rcS" /* Initscript. */
52 #define PATH_DEFAULT "PATH=/usr/local/sbin:/sbin:/bin:/usr/sbin:/usr/bin"
56 static char *console = DEV_CONSOLE;
57 static char *second_console = VT_SECONDARY;
58 static char *log = VT_LOG;
59 static int kernel_version = 0;
62 /* try to open up the specified device */
63 int device_open(char *device, int mode)
67 m = mode | O_NONBLOCK;
69 /* Retry up to 5 times */
70 for (f = 0; f < 5; f++)
71 if ((fd = open(device, m)) >= 0)
75 /* Reset original flags. */
77 fcntl(fd, F_SETFL, mode);
81 /* print a message to the specified device:
82 * device may be bitwise-or'd from LOG | CONSOLE */
83 void message(int device, char *fmt, ...)
89 /* Take full control of the log tty, and never close it.
90 * It's mine, all mine! Muhahahaha! */
93 /* don't even try to log, because there is no such console */
95 /* log to main console instead */
98 else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
100 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
106 if ( (device & LOG) && (log_fd >= 0) ) {
107 va_start(arguments, fmt);
108 vdprintf(log_fd, fmt, arguments);
111 if (device & CONSOLE) {
112 /* Always send console messages to /dev/console so people will see them. */
113 if ((fd = device_open(DEV_CONSOLE, O_WRONLY|O_NOCTTY|O_NDELAY)) >= 0) {
114 va_start(arguments, fmt);
115 vdprintf(fd, fmt, arguments);
119 fprintf(stderr, "Bummer, can't print: ");
120 va_start(arguments, fmt);
121 vfprintf(stderr, fmt, arguments);
129 /* Set terminal settings to reasonable defaults */
130 void set_term( int fd)
133 static const char control_characters[] = {
134 '\003', '\034', '\177', '\030', '\004', '\0',
135 '\1', '\0', '\021', '\023', '\032', '\0', '\022',
136 '\017', '\027', '\026', '\0'
141 /* Make it be sane */
142 tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
143 tty.c_cflag |= HUPCL|CLOCAL;
146 tty.c_iflag = IGNPAR|ICRNL|IXON|IXOFF|IXANY;
148 /* use line dicipline 0 */
152 tty.c_oflag = OPOST|ONLCR;
155 tty.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOPRT|ECHOKE|IEXTEN;
158 memcpy(tty.c_cc, control_characters, sizeof(control_characters));
160 tcsetattr(fd, TCSANOW, &tty);
163 /* How much memory does this machine have? */
164 static int mem_total()
167 char *p = "/proc/meminfo";
169 const char pattern[] = "MemTotal:";
171 if ((f = fopen(p, "r")) < 0) {
172 message(LOG, "Error opening %s: %s\n", p, strerror( errno));
175 while (NULL != fgets(s, 79, f)) {
176 p = strstr(s, pattern);
179 return (atoi(p + strlen(pattern)));
185 static void console_init()
188 int tried_devcons = 0;
189 int tried_vtprimary = 0;
190 struct serial_struct sr;
193 if ((s = getenv("CONSOLE")) != NULL) {
197 /* sparc kernel supports console=tty[ab] parameter which is also
198 * passed to init, so catch it here */
199 else if ((s = getenv("console")) != NULL) {
200 /* remap tty[ab] to /dev/ttyS[01] */
201 if (strcmp( s, "ttya" )==0)
202 console = SERIAL_CON0;
203 else if (strcmp( s, "ttyb" )==0)
204 console = SERIAL_CON1;
209 static char the_console[13];
211 console = the_console;
212 /* 2.2 kernels: identify the real console backend and try to use it */
213 if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
214 /* this is a serial console */
215 snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line );
217 else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
218 /* this is linux virtual tty */
219 snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active );
221 console = DEV_CONSOLE;
226 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
227 /* Can't open selected console -- try /dev/console */
228 if (!tried_devcons) {
230 console = DEV_CONSOLE;
233 /* Can't open selected console -- try vt1 */
234 if (!tried_vtprimary) {
236 console = VT_PRIMARY;
242 /* Perhaps we should panic here? */
243 console = "/dev/null";
245 /* check for serial console and disable logging to tty3 & running a
247 if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
249 second_console = NULL;
253 message(LOG, "console=%s\n", console );
256 static int waitfor(int pid)
260 message(LOG, "Waiting for process %d.\n", pid);
261 while ((wpid = wait(&status)) != pid) {
263 message(LOG, "pid %d exited, status=0x%x.\n", wpid, status);
269 static pid_t run(const char * const* command,
270 char *terminal, int get_enter)
274 const char * const* cmd = command+1;
275 static const char press_enter[] =
276 "\nPlease press Enter to activate this console. ";
278 if ((pid = fork()) == 0) {
285 /* Reset signal handlers set for parent process */
286 signal(SIGUSR1, SIG_DFL);
287 signal(SIGUSR2, SIG_DFL);
288 signal(SIGINT, SIG_DFL);
289 signal(SIGTERM, SIG_DFL);
291 if ((fd = device_open(terminal, O_RDWR)) < 0) {
292 message(LOG, "Bummer, can't open %s\r\n", terminal);
297 tcsetpgrp(0, getpgrp());
300 if (get_enter==TRUE) {
302 * Save memory by not exec-ing anything large (like a shell)
303 * before the user wants it. This is critical if swap is not
304 * enabled and the system has low memory. Generally this will
305 * be run on the second virtual console, and the first will
306 * be allowed to start a shell or whatever an init script
310 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
311 *cmd, getpid(), terminal );
312 write(1, press_enter, sizeof(press_enter) - 1);
316 /* Log the process name and args */
317 message(LOG, "Starting pid %d, console %s: '", getpid(), terminal);
318 while ( *cmd) message(LOG, "%s ", *cmd++);
319 message(LOG, "'\r\n");
321 /* Now run it. The new program will take over this PID,
322 * so nothing further in init.c should be run. */
323 execvp(*command, (char**)command+1);
325 message(LOG, "Bummer, could not run '%s'\n", command);
331 /* Make sure there is enough memory to do something useful. *
332 * Calls swapon if needed so be sure /proc is mounted. */
333 static void check_memory()
336 const char* const swap_on_cmd[] =
337 { "/bin/swapon", "swapon", "-a", 0};
339 if (mem_total() > 3500)
342 if (stat("/etc/fstab", &statbuf) == 0) {
343 /* Try to turn on swap */
344 waitfor(run(swap_on_cmd, log, FALSE));
345 if (mem_total() < 3500)
352 message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n");
356 static void shutdown_system(void)
358 const char* const swap_off_cmd[] = { "swapoff", "swapoff", "-a", 0};
359 const char* const umount_cmd[] = { "umount", "umount", "-a", "-n", 0};
362 /* Allow Ctrl-Alt-Del to reboot system. */
363 reboot(RB_ENABLE_CAD);
365 message(CONSOLE, "The system is going down NOW !!\r\n");
367 /* Send signals to every process _except_ pid 1 */
368 message(CONSOLE, "Sending SIGHUP to all processes.\r\n");
374 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
379 waitfor(run( swap_off_cmd, console, FALSE));
380 waitfor(run( umount_cmd, console, FALSE));
382 if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) {
383 /* bdflush, kupdate not needed for kernels >2.2.11 */
384 message(CONSOLE, "Flushing buffers.\r\n");
390 static void halt_signal(int sig)
394 "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
397 reboot(RB_HALT_SYSTEM);
398 //reboot(RB_POWER_OFF);
403 static void reboot_signal(int sig)
406 message(CONSOLE, "Please stand by while rebooting the system.\r\n");
414 extern int init_main(int argc, char **argv)
417 int wait_for_enter = TRUE;
421 const char* const rc_script_command[] = { INITSCRIPT, INITSCRIPT, 0};
422 const char* const shell_command[] = { SHELL, "-" SHELL, 0};
423 const char* const* tty0_command = shell_command;
424 const char* const* tty1_command = shell_command;
425 #ifdef BB_CONSOLE_CMD_IF_RC_SCRIPT_EXITS
426 const char* const rc_exit_command[] = BB_CONSOLE_CMD_IF_RC_SCRIPT_EXITS;
430 char *hello_msg_format =
431 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n";
433 char *hello_msg_format =
434 "init started: BusyBox v%s (%s) multi-call binary\r\n";
440 usage( "init\n\nInit is the parent of all processes.\n\n"
441 "This version of init is designed to be run only by the kernel\n");
445 /* Check if we are supposed to be in single user mode */
446 if ( argc > 1 && (!strcmp(argv[1], "single") ||
447 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
452 /* Set up sig handlers -- be sure to
453 * clear all of these in run() */
454 signal(SIGUSR1, halt_signal);
455 signal(SIGUSR2, reboot_signal);
456 signal(SIGINT, reboot_signal);
457 signal(SIGTERM, reboot_signal);
459 /* Turn off rebooting via CTL-ALT-DEL -- we get a
460 * SIGINT on CAD so we can shut things down gracefully... */
462 reboot(RB_DISABLE_CAD);
465 /* Figure out where the default console should be */
468 /* Close whatever files are open, and reset the console. */
475 /* Make sure PATH is set to something sane */
476 putenv(PATH_DEFAULT);
481 message(CONSOLE|LOG, hello_msg_format, BB_VER, BB_BT);
483 message(CONSOLE|LOG, hello_msg_format, getpid(), BB_VER, BB_BT);
488 if (mount ("proc", "/proc", "proc", 0, 0) == 0) {
489 message(CONSOLE|LOG, "Mounting /proc: done.\n");
490 kernel_version = get_kernel_revision();
492 message(CONSOLE|LOG, "Mounting /proc: failed!\n");
494 /* Make sure there is enough memory to do something useful. */
498 /* Make sure an init script exists before trying to run it */
499 if (run_rc == TRUE && stat(INITSCRIPT, &statbuf)==0) {
500 wait_for_enter = FALSE;
501 tty0_command = rc_script_command;
505 /* Ok, now launch the rc script and/or prepare to
506 * start up some VTs if somebody hits enter...
512 if (pid1 == 0 && tty0_command) {
513 pid1 = run(tty0_command, console, wait_for_enter);
515 if (pid2 == 0 && tty1_command && second_console) {
516 pid2 = run(tty1_command, second_console, TRUE);
518 wpid = wait(&status);
520 message(LOG, "pid %d exited, status=%x.\n", wpid, status);
522 /* Don't respawn init script if it exits */
524 if (run_rc == FALSE) {
527 #ifdef BB_CONSOLE_CMD_IF_RC_SCRIPT_EXITS
532 tty0_command=rc_exit_command;