busybox/init.c
1999-10-28 00:24:35 +00:00

449 lines
11 KiB
C

/*
* Mini init implementation for busybox
*
*
* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
* Adjusted by so many folks, it's impossible to keep track.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "internal.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/fcntl.h>
#include <sys/wait.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/reboot.h>
#include <sys/kdaemon.h>
#include <sys/sysmacros.h>
#include <linux/serial.h> /* for serial_struct */
#include <sys/vt.h> /* for vt_stat */
#include <sys/ioctl.h>
#define DEBUG_INIT
#define CONSOLE "/dev/console" /* Logical system console */
#define VT_PRIMARY "/dev/tty0" /* Virtual console master */
#define VT_SECONDARY "/dev/tty1" /* Virtual console master */
#define VT_LOG "/dev/tty2" /* Virtual console master */
#define SHELL "/bin/sh" /* Default shell */
#define INITSCRIPT "/etc/init.d/rcS" /* Initscript. */
#define PATH_DEFAULT "PATH=/usr/local/sbin:/sbin:/bin:/usr/sbin:/usr/bin"
static char *console = CONSOLE;
//static char *first_terminal = "/dev/tty1";
static char *second_terminal = "/dev/tty2";
static char *log = "/dev/tty3";
/* try to open up the specified device */
int device_open(char *device, int mode)
{
int m, f, fd = -1;
mode = m | O_NONBLOCK;
/* Retry up to 5 times */
for (f = 0; f < 5; f++)
if ((fd = open(device, m)) >= 0)
break;
if (fd < 0)
return fd;
/* Set original flags. */
if (m != mode)
fcntl(fd, F_SETFL, mode);
return fd;
}
/* print a message to the specified device */
void message(char *device, char *fmt, ...)
{
int fd;
va_list arguments;
if ((fd = device_open(device, O_WRONLY|O_NOCTTY|O_NDELAY)) >= 0) {
va_start(arguments, fmt);
vdprintf(fd, fmt, arguments);
va_end(arguments);
close(fd);
} else {
fprintf(stderr, "Bummer, can't print: ");
va_start(arguments, fmt);
vfprintf(stderr, fmt, arguments);
fflush(stderr);
va_end(arguments);
}
}
/* Set terminal settings to reasonable defaults */
void set_term( int fd)
{
struct termios tty;
tcgetattr(fd, &tty);
tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
tty.c_cflag |= HUPCL|CLOCAL;
tty.c_cc[VINTR] = 3;
tty.c_cc[VQUIT] = 28;
tty.c_cc[VERASE] = 127;
tty.c_cc[VKILL] = 24;
tty.c_cc[VEOF] = 4;
tty.c_cc[VTIME] = 0;
tty.c_cc[VMIN] = 1;
tty.c_cc[VSTART] = 17;
tty.c_cc[VSTOP] = 19;
tty.c_cc[VSUSP] = 26;
tty.c_iflag = IGNPAR|ICRNL|IXON|IXANY;
tty.c_oflag = OPOST|ONLCR;
tty.c_lflag = ISIG|ICANON|ECHO|ECHOCTL|ECHOPRT|ECHOKE;
tcsetattr(fd, TCSANOW, &tty);
}
static int mem_total()
{
char s[80];
char *p;
FILE *f;
const char pattern[] = "MemTotal:";
f = fopen("/proc/meminfo", "r");
while (NULL != fgets(s, 79, f)) {
p = strstr(s, pattern);
if (NULL != p) {
fclose(f);
return (atoi(p + strlen(pattern)));
}
}
return -1;
}
static void set_free_pages()
{
char s[80];
FILE *f;
f = fopen("/proc/sys/vm/freepages", "r");
fgets(s, 79, f);
if (atoi(s) < 32) {
fclose(f);
f = fopen("/proc/sys/vm/freepages", "w");
fprintf(f, "30\t40\t50\n");
printf("\nIncreased /proc/sys/vm/freepages values to 30/40/50\n");
}
fclose(f);
}
static void console_init()
{
int fd;
struct stat statbuf;
int tried_devcons = 0;
int tried_vtmaster = 0;
char *s;
fprintf(stderr, "entering console_init()\n");
if ((s = getenv("CONSOLE")) != NULL)
console = s;
else {
console = CONSOLE;
tried_devcons++;
}
if ( stat(CONSOLE, &statbuf) && S_ISLNK(statbuf.st_mode)) {
fprintf(stderr, "Yikes! /dev/console does not exist or is a symlink.\n");
}
while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
if (!tried_devcons) {
tried_devcons++;
console = CONSOLE;
continue;
}
if (!tried_vtmaster) {
tried_vtmaster++;
console = VT_PRIMARY;
continue;
}
break;
}
if (fd < 0)
console = "/dev/null";
else
close(fd);
fprintf(stderr, "console=%s\n", console);
}
static int waitfor(int pid)
{
int status, wpid;
message(log, "Waiting for process %d.\n", pid);
while ((wpid = wait(&status)) != pid) {
if (wpid > 0)
message(log, "pid %d exited, status=%x.\n", wpid, status);
}
return wpid;
}
static pid_t run(const char * const* command,
char *terminal, int get_enter)
{
int i;
pid_t pid;
static const char press_enter[] =
"\nPlease press Enter to activate this console. ";
if ((pid = fork()) == 0) {
/* Clean up */
close(0);
close(1);
close(2);
setsid();
open(terminal, O_RDWR);
dup(0);
dup(0);
tcsetpgrp(0, getpgrp());
set_term(0);
if (get_enter) {
/*
* Save memory by not exec-ing anything large (like a shell)
* before the user wants it. This is critical if swap is not
* enabled and the system has low memory. Generally this will
* be run on the second virtual console, and the first will
* be allowed to start a shell or whatever an init script
* specifies.
*/
char c;
write(0, press_enter, sizeof(press_enter) - 1);
read(0, &c, 1);
}
/* Log the process name and args */
/* Now run it. The new program will take over this PID,
* so nothing further in init.c should be run. */
message(log, "Executing '%s', pid(%d)\r\n", *command, getpid());
execvp(*command, (char**)command+1);
message(log, "Hmm. Trying as a script.\r\n");
/* If shell scripts are not executed, force the issue */
if (errno == ENOEXEC) {
char * args[16];
args[0] = SHELL;
args[1] = "-c";
args[2] = "exec";
for( i=0 ; i<16 && command[i]; i++)
args[3+i] = (char*)command[i];
args[i] = NULL;
execvp(*args, (char**)args+1);
}
message(log, "Could not execute '%s'\n", command);
exit(-1);
}
return pid;
}
#ifndef DEBUG_INIT
static void shutdown_system(void)
{
const char* const swap_off_cmd[] = { "/bin/swapoff", "-a", 0};
const char* const umount_cmd[] = { "/bin/umount", "-a", "-n", 0};
message(console, "The system is going down NOW !!\r\n");
sync();
/* Allow Ctrl-Alt-Del to reboot system. */
reboot(RB_ENABLE_CAD);
/* Send signals to every process _except_ pid 1 */
message(console, "Sending SIGHUP to all processes.\r\n");
kill(-1, SIGHUP);
sleep(2);
sync();
message(console, "Sending SIGKILL to all processes.\r\n");
kill(-1, SIGKILL);
sleep(1);
waitfor(run( swap_off_cmd, console, 0));
waitfor(run( umount_cmd, console, 0));
sync();
if (get_kernel_revision() <= 2 * 65536 + 2 * 256 + 11) {
/* Removed bdflush call, kupdate in kernels >2.2.11 */
bdflush(1, 0);
sync();
}
}
static void halt_signal(int sig)
{
shutdown_system();
message(console,
"The system is halted. Press CTRL-ALT-DEL or turn off power\r\n");
reboot(RB_POWER_OFF);
exit(0);
}
static void reboot_signal(int sig)
{
shutdown_system();
message(console, "Please stand by while rebooting the system.\r\n");
reboot(RB_AUTOBOOT);
exit(0);
}
#endif
extern int init_main(int argc, char **argv)
{
int run_rc = TRUE;
pid_t pid = 0;
pid_t pid1 = 0;
pid_t pid2 = 0;
struct stat statbuf;
const char* const swap_on_cmd[] = { "/bin/swapon", " -a ", 0};
const char* const init_commands[] = { SHELL, " -c", " exec ", INITSCRIPT, 0};
const char* const shell_commands[] = { SHELL, " -", 0};
const char* const* tty0_commands = init_commands;
const char* const* tty1_commands = shell_commands;
char *hello_msg_format =
"init(%d) started: BusyBox v%s (%s) multi-call binary\r\n";
const char *no_memory =
"Sorry, your computer does not have enough memory.\r\n";
pid = getpid();
#ifndef DEBUG_INIT
/* Set up sig handlers */
signal(SIGUSR1, halt_signal);
signal(SIGSEGV, halt_signal);
signal(SIGPWR, halt_signal);
signal(SIGALRM, halt_signal);
signal(SIGHUP, halt_signal);
signal(SIGUSR2, reboot_signal);
signal(SIGINT, reboot_signal);
signal(SIGTERM, reboot_signal);
/* Turn off rebooting via CTL-ALT-DEL -- we get a
* SIGINT on CAD so we can shut things down gracefully... */
reboot(RB_DISABLE_CAD);
#endif
/* Figure out where the default console should be */
console_init();
/* Close whatever files are open, and reset the console. */
close(0);
close(1);
close(2);
//set_term(0);
setsid();
/* Make sure PATH is set to something sane */
if (getenv("PATH") == NULL)
putenv(PATH_DEFAULT);
/* Hello world */
message(log, hello_msg_format, pid, BB_VER, BB_BT);
fprintf(stderr, hello_msg_format, pid, BB_VER, BB_BT);
/* Mount /proc */
if (mount("/proc", "/proc", "proc", 0, 0) == 0) {
fprintf(stderr, "Mounting /proc: done.\n");
message(log, "Mounting /proc: done.\n");
} else {
fprintf(stderr, "Mounting /proc: failed!\n");
message(log, "Mounting /proc: failed!\n");
}
/* Make sure there is enough memory to do something useful */
set_free_pages();
if (mem_total() < 2000) {
int retval;
retval = stat("/etc/fstab", &statbuf);
if (retval) {
fprintf(stderr, "%s", no_memory);
while (1) {
sleep(1);
}
} else {
/* Try to turn on swap */
waitfor(run(swap_on_cmd, console, 0));
if (mem_total() < 2000) {
fprintf(stderr, "%s", no_memory);
while (1) {
sleep(1);
}
}
}
}
/* Check if we are supposed to be in single user mode */
if ( argc > 1 && (!strcmp(argv[1], "single") ||
!strcmp(argv[1], "-s") || !strcmp(argv[1], "1"))) {
run_rc = FALSE;
tty0_commands = shell_commands;
tty1_commands = shell_commands;
}
/* Make sure an init script exists before trying to run it */
if (run_rc == TRUE && stat(INITSCRIPT, &statbuf)) {
tty0_commands = shell_commands;
tty1_commands = shell_commands;
}
/* Ok, now launch the rc script and/or prepare to
* start up some VTs if somebody hits enter...
*/
for (;;) {
pid_t wpid;
int status;
if (pid1 == 0 && tty0_commands) {
pid1 = run(tty0_commands, console, 1);
}
if (pid2 == 0 && tty1_commands) {
pid2 = run(tty1_commands, second_terminal, 1);
}
wpid = wait(&status);
if (wpid > 0 ) {
message(log, "pid %d exited, status=%x.\n", wpid, status);
}
/* Don't respawn an init script if it exits */
if (run_rc == FALSE && wpid == pid1) {
pid1 = 0;
}
if (wpid == pid2) {
pid2 = 0;
}
sleep(1);
}
}