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>
46 #define CONSOLE "/dev/console" /* Logical system console */
47 #define VT_PRIMARY "/dev/tty0" /* Virtual console master */
48 #define VT_SECONDARY "/dev/tty1" /* Virtual console master */
49 #define VT_LOG "/dev/tty2" /* Virtual console master */
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"
54 static char *console = CONSOLE;
55 static char *second_terminal = "/dev/tty2";
56 static char *log = "/dev/tty3";
60 /* try to open up the specified device */
61 int device_open(char *device, int mode)
65 mode = m | O_NONBLOCK;
67 /* Retry up to 5 times */
68 for (f = 0; f < 5; f++)
69 if ((fd = open(device, m)) >= 0)
73 /* Set original flags. */
75 fcntl(fd, F_SETFL, mode);
79 /* print a message to the specified device */
80 void message(char *device, char *fmt, ...)
85 if ((fd = device_open(device, O_WRONLY | O_NOCTTY | O_NDELAY)) >= 0) {
86 va_start(arguments, fmt);
87 vdprintf(fd, fmt, arguments);
91 vprintf(fmt, arguments);
94 /* Set terminal settings to reasonable defaults */
100 if ((fd = device_open(console, O_RDWR | O_NOCTTY)) < 0) {
101 message(log, "can't open %s\n", console);
104 ioctl(fd, TCGETS, &tty);
105 tty.c_cflag &= CBAUD | CBAUDEX | CSIZE | CSTOPB | PARENB | PARODD;
106 tty.c_cflag |= HUPCL | CLOCAL;
109 tty.c_cc[VQUIT] = 28;
110 tty.c_cc[VERASE] = 127;
111 tty.c_cc[VKILL] = 24;
115 tty.c_cc[VSTART] = 17;
116 tty.c_cc[VSTOP] = 19;
117 tty.c_cc[VSUSP] = 26;
119 /* Set pre and post processing */
120 tty.c_iflag = IGNPAR | ICRNL | IXON | IXANY;
121 tty.c_oflag = OPOST | ONLCR;
122 tty.c_lflag = ISIG | ICANON | ECHO | ECHOCTL | ECHOPRT | ECHOKE;
124 /* Now set the terminal line. */
125 ioctl(fd, TCSETS, &tty);
129 static int mem_total()
134 const char pattern[] = "MemTotal:";
136 f = fopen("/proc/meminfo", "r");
137 while (NULL != fgets(s, 79, f)) {
138 p = strstr(s, pattern);
141 return (atoi(p + strlen(pattern)));
147 static void set_free_pages()
152 f = fopen("/proc/sys/vm/freepages", "r");
156 f = fopen("/proc/sys/vm/freepages", "w");
157 fprintf(f, "30\t40\t50\n");
158 printf("\nIncreased /proc/sys/vm/freepages values to 30/40/50\n");
164 static void console_init()
167 int tried_devcons = 0;
168 int tried_vtmaster = 0;
171 if ((s = getenv("CONSOLE")) != NULL)
177 while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
178 if (!tried_devcons) {
183 if (!tried_vtmaster) {
185 console = VT_PRIMARY;
191 console = "/dev/null";
196 static int waitfor(int pid)
200 message(log, "Waiting for process %d.\n", pid);
201 while ((wpid = wait(&status)) != pid) {
203 message(log, "pid %d exited, status=%x.\n", wpid, status);
208 static int run(const char *command, char *terminal, int get_enter)
214 static const char press_enter[] =
215 "\nPlease press Enter to activate this console. ";
218 /* Make a proper command from the command string */
219 strcpy(buf, command);
221 for (f = 1; f < 15; f++) {
222 /* Skip white space */
223 while (*ptr == ' ' || *ptr == '\t')
226 /* May be trailing space.. */
229 /* Skip this `word' */
230 while (*ptr && *ptr != ' ' && *ptr != '\t' && *ptr != '#')
232 /* If end-of-line, break */
233 if (*ptr == '#' || *ptr == 0) {
238 /* End word with \0 and continue */
244 if ((pid = fork()) == 0) {
251 if ((f = device_open(terminal, O_RDWR | O_NOCTTY)) < 0) {
252 message(log, "open(%s) failed: %s\n", terminal, strerror(errno));
257 tcsetpgrp(0, getpgrp());
262 * Save memory by not exec-ing anything large (like a shell)
263 * before the user wants it. This is critical if swap is not
264 * enabled and the system has low memory. Generally this will
265 * be run on the second virtual console, and the first will
266 * be allowed to start a shell or whatever an init script
270 write(1, press_enter, sizeof(press_enter) - 1);
272 message(console, "Got an enter\r\n");
275 /* Log the process name and args */
276 message(console, "Executing ");
277 message(console, "'%s'\r\n", command);
279 /* Now run it. This should take over the PID, so nothing
280 * further in init.c should be run by this PID. */
281 execvp(args[1], args + 1);
283 message(console, "Hmm. Trying as a script.\r\n");
284 /* If shell scripts are not executed, force the issue */
285 if (errno == ENOEXEC) {
289 strcpy(buf, "exec ");
290 strcat(buf, command);
293 execvp(args[1], args + 1);
295 message(console, "Could not execute '%s'\n", command);
302 static void shutdown_system(void)
305 message(console, "The system is going down NOW !!\r\n");
307 /* Allow Ctrl-Alt-Del to reboot system. */
308 reboot(RB_ENABLE_CAD);
310 /* Send signals to every process _except_ pid 1 */
311 message(console, "Sending SIGHUP to all processes.\r\n");
315 message(console, "Sending SIGKILL to all processes.\r\n");
318 waitfor(run("/bin/swapoff -a", console, 0));
319 waitfor(run("/bin/umount -a -n", console, 0));
321 if (get_kernel_revision() <= 2 * 65536 + 2 * 256 + 11) {
322 /* Removed bdflush call, kupdate in kernels >2.2.11 */
328 static void halt_signal(int sig)
332 "The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
333 reboot(RB_POWER_OFF);
337 static void reboot_signal(int sig)
340 message(console, "Please stand by while rebooting the system.\r\n");
347 extern int init_main(int argc, char **argv)
353 const char *init_commands = SHELL "-c exec " INITSCRIPT;
354 const char *shell_commands = SHELL;
355 const char *tty0_commands = init_commands;
356 const char *tty1_commands = shell_commands;
357 char *hello_msg_format =
358 "init started: BusyBox v%s (%s) multi-call binary\r\n";
359 const char *no_memory =
360 "Sorry, your computer does not have enough memory.\r\n";
364 /* Set up sig handlers */
365 signal(SIGUSR1, halt_signal);
366 signal(SIGSEGV, halt_signal);
367 signal(SIGPWR, halt_signal);
368 signal(SIGALRM, halt_signal);
369 signal(SIGHUP, halt_signal);
370 signal(SIGUSR2, reboot_signal);
371 signal(SIGINT, reboot_signal);
372 signal(SIGTERM, reboot_signal);
374 /* Figure out where the default console should be */
377 /* Turn off rebooting via CTL-ALT-DEL -- we get a
378 * SIGINT on CAD so we can shut things down gracefully... */
380 reboot(RB_DISABLE_CAD);
383 /* Close whatever files are open, and reset the console. */
390 /* Make sure PATH is set to something sane */
391 if (getenv("PATH") == NULL)
392 putenv(PATH_DEFAULT);
395 message(log, hello_msg_format, BB_VER, BB_BT);
396 message(console, hello_msg_format, BB_VER, BB_BT);
399 if (mount("/proc", "/proc", "proc", 0, 0)) {
400 message(log, "Mounting /proc: failed!\n");
401 message(console, "Mounting /proc: failed!\r\n");
403 message(console, "Mounting /proc: done.\r\n");
406 /* Make sure there is enough memory to do something useful */
408 if (mem_total() < 2000) {
410 retval = stat("/etc/fstab", &statbuf);
412 message(console, "%s", no_memory);
417 /* Try to turn on swap */
418 waitfor(run("/bin/swapon -a", console, 0));
419 if (mem_total() < 2000) {
420 message(console, "%s", no_memory);
428 /* Check if we are supposed to be in single user mode */
429 if ( argc > 1 && (!strcmp(argv[1], "single") ||
430 !strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
432 tty0_commands = shell_commands;
436 /* Make sure an init script exists before trying to run it */
437 if (run_rc == TRUE && stat(INITSCRIPT, &statbuf)) {
438 tty0_commands = shell_commands;
439 tty1_commands = shell_commands;
442 /* Ok, now launch the rc script and/or prepare to
443 * start up some VTs if somebody hits enter...
449 if (pid1 == 0 && tty0_commands) {
450 pid1 = run(tty0_commands, console, 1);
452 if (pid2 == 0 && tty1_commands) {
453 pid2 = run(tty1_commands, second_terminal, 1);
455 wpid = wait(&status);
456 if (wpid > 0 && wpid != pid1) {
457 message(log, "pid %d exited, status=%x.\n", wpid, status);
459 /* Don't respawn an init script if it exits */
460 if (run_rc == FALSE && wpid == pid1) {