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 #include <sys/syslog.h>
47 #define DEV_CONSOLE "/dev/console" /* Logical system console */
48 #define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
49 #define VT_SECONDARY "/dev/tty2" /* Virtual console */
50 #define VT_LOG "/dev/tty3" /* Virtual console */
51 #define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
52 #define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
53 #define SHELL "/bin/sh" /* Default shell */
54 #define INITSCRIPT "/etc/init.d/rcS" /* Initscript. */
55 #define PATH_DEFAULT "PATH=/usr/local/sbin:/sbin:/bin:/usr/sbin:/usr/bin"
59 static char *console = DEV_CONSOLE;
60 static char *second_console = VT_SECONDARY;
61 static char *log = VT_LOG;
62 static int kernel_version = 0;
65 /* try to open up the specified device */
66 int device_open(char *device, int mode)
70 m = mode | O_NONBLOCK;
72 /* Retry up to 5 times */
73 for (f = 0; f < 5; f++)
74 if ((fd = open(device, m)) >= 0)
78 /* Reset original flags. */
80 fcntl(fd, F_SETFL, mode);
84 /* print a message to the specified device:
85 * device may be bitwise-or'd from LOG | CONSOLE */
86 void message(int device, char *fmt, ...)
92 /* Log the message to syslogd */
95 va_start(arguments, fmt);
96 vsnprintf(msg, sizeof(msg), fmt, arguments);
98 syslog(LOG_DAEMON|LOG_NOTICE, msg);
102 static int log_fd=-1;
104 /* Take full control of the log tty, and never close it.
105 * It's mine, all mine! Muhahahaha! */
108 /* don't even try to log, because there is no such console */
110 /* log to main console instead */
113 else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
115 fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
120 if ( (device & LOG) && (log_fd >= 0) ) {
121 va_start(arguments, fmt);
122 vdprintf(log_fd, fmt, arguments);
127 if (device & CONSOLE) {
128 /* Always send console messages to /dev/console so people will see them. */
129 if ((fd = device_open(DEV_CONSOLE, O_WRONLY|O_NOCTTY|O_NDELAY)) >= 0) {
130 va_start(arguments, fmt);
131 vdprintf(fd, fmt, arguments);
135 fprintf(stderr, "Bummer, can't print: ");
136 va_start(arguments, fmt);
137 vfprintf(stderr, fmt, arguments);
145 /* Set terminal settings to reasonable defaults */
146 void set_term( int fd)
150 static const char control_characters[] = {
151 '\003', '\034', '\177', '\030', '\004', '\0',
152 '\1', '\0', '\021', '\023', '\032', '\0', '\022',
153 '\017', '\027', '\026', '\0'
156 static const char control_characters[] = {
157 '\003', '\034', '\177', '\025', '\004', '\0',
158 '\1', '\0', '\021', '\023', '\032', '\0', '\022',
159 '\017', '\027', '\026', '\0'
165 /* set control chars */
166 memcpy(tty.c_cc, control_characters, sizeof(control_characters));
168 /* use line dicipline 0 */
171 /* Make it be sane */
172 //tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
173 //tty.c_cflag |= HUPCL|CLOCAL;
176 tty.c_iflag = ICRNL|IXON|IXOFF;
179 tty.c_oflag = OPOST|ONLCR;
182 tty.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
184 tcsetattr(fd, TCSANOW, &tty);
187 /* How much memory does this machine have? */
188 static int mem_total()
191 char *p = "/proc/meminfo";
193 const char pattern[] = "MemTotal:";
195 if ((f = fopen(p, "r")) < 0) {
196 message(LOG, "Error opening %s: %s\n", p, strerror( errno));
199 while (NULL != fgets(s, 79, f)) {
200 p = strstr(s, pattern);
203 return (atoi(p + strlen(pattern)));
209 static void console_init()
212 int tried_devcons = 0;
213 int tried_vtprimary = 0;
214 struct serial_struct sr;
217 if ((s = getenv("CONSOLE")) != NULL) {
221 /* sparc kernel supports console=tty[ab] parameter which is also
222 * passed to init, so catch it here */
223 else if ((s = getenv("console")) != NULL) {
224 /* remap tty[ab] to /dev/ttyS[01] */
225 if (strcmp( s, "ttya" )==0)
226 console = SERIAL_CON0;
227 else if (strcmp( s, "ttyb" )==0)
228 console = SERIAL_CON1;
233 static char the_console[13];
235 console = the_console;
236 /* 2.2 kernels: identify the real console backend and try to use it */
237 if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
238 /* this is a serial console */
239 snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line );
241 else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
242 /* this is linux virtual tty */
243 snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active );
245 console = DEV_CONSOLE;
250 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
251 /* Can't open selected console -- try /dev/console */
252 if (!tried_devcons) {
254 console = DEV_CONSOLE;
257 /* Can't open selected console -- try vt1 */
258 if (!tried_vtprimary) {
260 console = VT_PRIMARY;
266 /* Perhaps we should panic here? */
267 console = "/dev/null";
269 /* check for serial console and disable logging to tty3 & running a
271 if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
272 message(LOG|CONSOLE, "serial console detected. Disabling 2nd virtual terminal.\r\n", console );
274 second_console = NULL;
278 message(LOG, "console=%s\n", console );
281 static int waitfor(int pid)
285 message(LOG, "Waiting for process %d.\n", pid);
286 while ((wpid = wait(&status)) != pid) {
288 message(LOG, "pid %d exited, status=0x%x.\n", wpid, status);
294 static pid_t run(const char * const* command,
295 char *terminal, int get_enter)
299 const char * const* cmd = command+1;
300 static const char press_enter[] =
301 "\nPlease press Enter to activate this console. ";
303 if ((pid = fork()) == 0) {
310 /* Reset signal handlers set for parent process */
311 signal(SIGUSR1, SIG_DFL);
312 signal(SIGUSR2, SIG_DFL);
313 signal(SIGINT, SIG_DFL);
314 signal(SIGTERM, SIG_DFL);
316 if ((fd = device_open(terminal, O_RDWR)) < 0) {
317 message(LOG, "Bummer, can't open %s\r\n", terminal);
322 tcsetpgrp(0, getpgrp());
325 if (get_enter==TRUE) {
327 * Save memory by not exec-ing anything large (like a shell)
328 * before the user wants it. This is critical if swap is not
329 * enabled and the system has low memory. Generally this will
330 * be run on the second virtual console, and the first will
331 * be allowed to start a shell or whatever an init script
335 message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
336 *cmd, getpid(), terminal );
337 write(1, press_enter, sizeof(press_enter) - 1);
341 /* Log the process name and args */
342 message(LOG, "Starting pid %d, console %s: '", getpid(), terminal);
343 while ( *cmd) message(LOG, "%s ", *cmd++);
344 message(LOG, "'\r\n");
346 /* Now run it. The new program will take over this PID,
347 * so nothing further in init.c should be run. */
348 execvp(*command, (char**)command+1);
350 message(LOG, "Bummer, could not run '%s'\n", command);
356 /* Make sure there is enough memory to do something useful. *
357 * Calls swapon if needed so be sure /proc is mounted. */
358 static void check_memory()
361 const char* const swap_on_cmd[] =
362 { "/bin/swapon", "swapon", "-a", 0};
364 if (mem_total() > 3500)
367 if (stat("/etc/fstab", &statbuf) == 0) {
368 /* Try to turn on swap */
369 waitfor(run(swap_on_cmd, log, FALSE));
370 if (mem_total() < 3500)
377 message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n");
381 static void shutdown_system(void)
383 const char* const swap_off_cmd[] = { "swapoff", "swapoff", "-a", 0};
384 const char* const umount_cmd[] = { "umount", "umount", "-a", "-n", 0};
387 /* Allow Ctrl-Alt-Del to reboot system. */
388 reboot(RB_ENABLE_CAD);
390 message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
392 /* Send signals to every process _except_ pid 1 */
393 message(CONSOLE, "Sending SIGHUP to all processes.\r\n");
399 message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
404 message(CONSOLE, "Disabling swap.\r\n");
405 waitfor(run( swap_off_cmd, console, FALSE));
406 message(CONSOLE, "Unmounting filesystems.\r\n");
407 waitfor(run( umount_cmd, console, FALSE));
409 if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) {
410 /* bdflush, kupdate not needed for kernels >2.2.11 */
411 message(CONSOLE, "Flushing buffers.\r\n");
417 static void halt_signal(int sig)
421 "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
424 reboot(RB_HALT_SYSTEM);
425 //reboot(RB_POWER_OFF);
430 static void reboot_signal(int sig)
433 message(CONSOLE, "Please stand by while rebooting the system.\r\n");
441 extern int init_main(int argc, char **argv)
444 int wait_for_enter = TRUE;
448 const char* const rc_script_command[] = { INITSCRIPT, INITSCRIPT, 0};
449 const char* const shell_command[] = { SHELL, "-" SHELL, 0};
450 const char* const* tty0_command = shell_command;
451 const char* const* tty1_command = shell_command;
452 #ifdef BB_INIT_CMD_IF_RC_SCRIPT_EXITS
453 const char* const rc_exit_command[] = { "BB_INIT_CMD_IF_RC_SCRIPT_EXITS",
454 "BB_INIT_CMD_IF_RC_SCRIPT_EXITS", 0 };
458 char *hello_msg_format =
459 "init(%d) started: BusyBox v%s (%s) multi-call binary\r\n";
461 char *hello_msg_format =
462 "init started: BusyBox v%s (%s) multi-call binary\r\n";
467 /* Expect to be PID 1 iff we are run as init (not linuxrc) */
468 if (getpid() != 1 && strstr(argv[0], "init")!=NULL ) {
469 usage( "init\n\nInit is the parent of all processes.\n\n"
470 "This version of init is designed to be run only by the kernel\n");
474 /* Check if we are supposed to be in single user mode */
475 if ( argc > 1 && (!strcmp(argv[1], "single") ||
476 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
481 /* Set up sig handlers -- be sure to
482 * clear all of these in run() */
483 signal(SIGUSR1, halt_signal);
484 signal(SIGUSR2, reboot_signal);
485 signal(SIGINT, reboot_signal);
486 signal(SIGTERM, reboot_signal);
488 /* Turn off rebooting via CTL-ALT-DEL -- we get a
489 * SIGINT on CAD so we can shut things down gracefully... */
491 reboot(RB_DISABLE_CAD);
494 /* Figure out where the default console should be */
497 /* Close whatever files are open, and reset the console. */
504 /* Make sure PATH is set to something sane */
505 putenv(PATH_DEFAULT);
510 message(CONSOLE|LOG, hello_msg_format, BB_VER, BB_BT);
512 message(CONSOLE|LOG, hello_msg_format, getpid(), BB_VER, BB_BT);
517 if (mount ("proc", "/proc", "proc", 0, 0) == 0) {
518 message(CONSOLE|LOG, "Mounting /proc: done.\n");
519 kernel_version = get_kernel_revision();
521 message(CONSOLE|LOG, "Mounting /proc: failed!\n");
523 /* Make sure there is enough memory to do something useful. */
527 /* Make sure an init script exists before trying to run it */
528 if (run_rc == TRUE && stat(INITSCRIPT, &statbuf)==0) {
529 wait_for_enter = FALSE;
530 tty0_command = rc_script_command;
534 /* Ok, now launch the rc script and/or prepare to
535 * start up some VTs if somebody hits enter...
541 if (pid1 == 0 && tty0_command) {
542 pid1 = run(tty0_command, console, wait_for_enter);
544 if (pid2 == 0 && tty1_command && second_console) {
545 pid2 = run(tty1_command, second_console, TRUE);
547 wpid = wait(&status);
549 message(LOG, "pid %d exited, status=%x.\n", wpid, status);
551 /* Don't respawn init script if it exits */
553 if (run_rc == FALSE) {
556 #ifdef BB_INIT_CMD_IF_RC_SCRIPT_EXITS
561 tty0_command=rc_exit_command;