busybox/init.c
Eric Andersen 0460ff2e5d Stuf
1999-10-25 23:32:44 +00:00

487 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 int maxproclen=0;
static char* argv0;
static char* console = CONSOLE;
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);
}
/* Set terminal settings to reasonable defaults */
void set_term()
{
int fd;
struct termios tty;
if ((fd = device_open(console, O_RDWR|O_NOCTTY)) < 0) {
message(log, "can't open %s", console);
return;
}
ioctl(fd, TCGETS, &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;
/* Set pre and post processing */
tty.c_iflag = IGNPAR|ICRNL|IXON|IXANY;
tty.c_oflag = OPOST|ONLCR;
tty.c_lflag = ISIG|ICANON|ECHO|ECHOCTL|ECHOPRT|ECHOKE;
/* Now set the terminal line. */
ioctl(fd, TCSETS, &tty);
close( fd);
}
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;
int tried_devcons = 0;
int tried_vtmaster = 0;
char *s;
if ((s = getenv("CONSOLE")) != NULL)
console = s;
else {
console = CONSOLE;
tried_devcons++;
}
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);
}
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 int
run(const char* command, char* terminal, int get_enter)
{
int f, pid;
char *args[16];
char buf[256];
char* ptr;
static const char press_enter[] =
"\nPlease press Enter to activate this console. ";
/* Make a proper command from the command string */
strcpy(buf, command);
ptr = buf;
for(f = 1; f < 15; f++) {
/* Skip white space */
while(*ptr == ' ' || *ptr == '\t') ptr++;
args[f] = ptr;
/* May be trailing space.. */
if (*ptr == 0) break;
/* Skip this `word' */
while(*ptr && *ptr != ' ' && *ptr != '\t' && *ptr != '#')
ptr++;
/* If end-of-line, break */
if (*ptr == '#' || *ptr == 0) {
f++;
*ptr = 0;
break;
}
/* End word with \0 and continue */
args[f] = NULL;
}
args[0] = args[1];
if ((pid = fork()) == 0) {
/* Clean up */
close(0);
close(1);
close(2);
setsid();
if ((f = device_open(terminal, O_RDWR|O_NOCTTY)) < 0) {
message( log, "open(%s) failed: %s", terminal, strerror(errno));
return -1;
}
dup(f);
dup(f);
tcsetpgrp(0, getpgrp());
set_term();
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(1, press_enter, sizeof(press_enter) - 1);
read(0, &c, 1);
}
/* Log the process name and args */
message(log, "Executing '%s'\n", command);
/* Now run it. This should take over the PID, so nothing
* further in init.c should be run by this PID. */
execvp(args[1], args + 1);
/* If shell scripts are not executed, force the issue */
if (errno == ENOEXEC) {
char buf[256];
args[1] = SHELL;
args[2] = "-c";
strcpy(buf, "exec ");
strcat(buf, command);
args[3] = buf;
args[4] = NULL;
execvp(args[1], args + 1);
}
message(log, "Could not execute '%s'\n", command, strerror(errno));
exit(-1);
}
return pid;
}
#ifndef DEBUG_INIT
static void
shutdown_system(void)
{
message(console, "The system is going down NOW !!");
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("/bin/swapoff -a", console, 0));
waitfor(run("/bin/umount -a -n", 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
int setproctitle(char *fmt, ...)
{
va_list ap;
int len;
char buf[256];
buf[0] = 0;
va_start(ap, fmt);
len = vsprintf(buf, fmt, ap);
va_end(ap);
memset(argv0, 0, maxproclen + 1);
strncpy(argv0, buf, maxproclen);
return len;
}
extern int
init_main(int argc, char * * argv)
{
int run_rc = TRUE;
int pid1 = 0;
int pid2 = 0;
struct stat statbuf;
const char* init_commands = SHELL "-c exec " INITSCRIPT;
const char* shell_commands = SHELL;
const char* tty0_commands = init_commands;
const char* tty1_commands = shell_commands;
const char* no_memory =
"Sorry, your computer does not have enough memory.\n";
/* For later use */
argv0 = argv[0];
maxproclen = strlen(argv[0]);
setproctitle("init [boot]");
#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);
#endif
/* Figure out where the default console should be */
console_init();
/* Turn off rebooting via CTL-ALT-DEL -- we get a
* SIGINT on CAD so we can shut things down gracefully... */
#ifndef DEBUG_INIT
reboot(RB_DISABLE_CAD);
#endif
/* Close whatever files are open, and reset the console. */
close(0);
close(1);
close(2);
set_term();
setsid();
/* Make sure PATH is set to something sane */
if (getenv("PATH") == NULL)
putenv(PATH_DEFAULT);
/* Hello world */
message(console, "%s started: BusyBox v%s (%s) multi-call binary",
argv[0], BB_VER, BB_BT);
message(log, "%s started: BusyBox v%s (%s) multi-call binary",
argv[0], BB_VER, BB_BT);
/* Mount /proc */
message(console, "Mounting /proc: \n");
if (mount("/proc","/proc","proc",0,0)) {
message(log, "%s: could not mount /proc!\n", argv[0]);
message(console, "failed!\n");
}
message(console, "done.\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) {
message(console, "%s", no_memory);
while (1) { sleep(1);}
} else {
/* Try to turn on swap */
waitfor(run("/bin/swapon -a", console, 0));
if (mem_total() < 2000) {
message(console, "%s", no_memory);
while (1) { sleep(1);}
}
}
}
/* Check if we are supposed to be in single user mode */
if (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || !strcmp(argv[1], "1")) {
run_rc = FALSE;
tty0_commands = shell_commands;
tty1_commands = 0;
setproctitle("init [S]");
} else {
setproctitle("init [1]");
}
/* 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 ( ; ; ) {
int 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 && wpid != pid1) {
message(log, "pid %d exited, status=%x.\n", wpid, status);
}
if ( wpid == pid2 ) {
pid2 = 0;
}
sleep(1);
}
}