busybox/init.c
Erik Andersen 4d1d0113fd Reworked the source so it will compile and run under glibc 2.0.7
and linux kernel 2.0.36 (though the dubious reasons why someone
would want to do that defy imagination ;)
 -Erik
1999-12-17 18:44:15 +00:00

610 lines
16 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 <paths.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>
#include <linux/version.h>
#ifdef BB_SYSLOGD
#include <sys/syslog.h>
#endif
#if ! defined BB_FEATURE_USE_PROCFS
#error Sorry, I depend on the /proc filesystem right now.
#endif
#ifndef KERNEL_VERSION
#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
#endif
#define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
#define VT_SECONDARY "/dev/tty2" /* Virtual console */
#define VT_LOG "/dev/tty3" /* Virtual console */
#define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
#define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
#define GETTY "/sbin/getty" /* Default location of getty */
#define SHELL "/bin/sh" /* Default shell */
#define INITSCRIPT "/etc/init.d/rcS" /* Initscript. */
#define LOG 0x1
#define CONSOLE 0x2
static char *console = _PATH_CONSOLE;
static char *second_console = VT_SECONDARY;
static char *log = VT_LOG;
static int kernel_version = 0;
/* try to open up the specified device */
int device_open(char *device, int mode)
{
int m, f, fd = -1;
m = mode | 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;
/* Reset original flags. */
if (m != mode)
fcntl(fd, F_SETFL, mode);
return fd;
}
/* print a message to the specified device:
* device may be bitwise-or'd from LOG | CONSOLE */
void message(int device, char *fmt, ...)
{
int fd;
va_list arguments;
#ifdef BB_SYSLOGD
/* Log the message to syslogd */
if (device & LOG ) {
char msg[1024];
va_start(arguments, fmt);
vsnprintf(msg, sizeof(msg), fmt, arguments);
va_end(arguments);
syslog(LOG_DAEMON|LOG_NOTICE, msg);
}
#else
static int log_fd=-1;
/* Take full control of the log tty, and never close it.
* It's mine, all mine! Muhahahaha! */
if (log_fd < 0) {
if (log == NULL) {
/* don't even try to log, because there is no such console */
log_fd = -2;
/* log to main console instead */
device = CONSOLE;
}
else if ((log_fd = device_open(log, O_RDWR|O_NDELAY)) < 0) {
log_fd=-1;
fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
fflush(stderr);
return;
}
}
if ( (device & LOG) && (log_fd >= 0) ) {
va_start(arguments, fmt);
vdprintf(log_fd, fmt, arguments);
va_end(arguments);
}
#endif
if (device & CONSOLE) {
/* Always send console messages to /dev/console so people will see them. */
if ((fd = device_open(_PATH_CONSOLE, 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;
static const char control_characters[] = {
'\003', '\034', '\177', '\025', '\004', '\0',
'\1', '\0', '\021', '\023', '\032', '\0', '\022',
'\017', '\027', '\026', '\0'
};
tcgetattr(fd, &tty);
/* set control chars */
memcpy(tty.c_cc, control_characters, sizeof(control_characters));
/* use line dicipline 0 */
tty.c_line = 0;
/* Make it be sane */
//tty.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
//tty.c_cflag |= HUPCL|CLOCAL;
/* input modes */
tty.c_iflag = ICRNL|IXON|IXOFF;
/* output modes */
tty.c_oflag = OPOST|ONLCR;
/* local modes */
tty.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
tcsetattr(fd, TCSANOW, &tty);
}
/* How much memory does this machine have? */
static int mem_total()
{
char s[80];
char *p = "/proc/meminfo";
FILE *f;
const char pattern[] = "MemTotal:";
if ((f = fopen(p, "r")) < 0) {
message(LOG, "Error opening %s: %s\n", p, strerror( errno));
return -1;
}
while (NULL != fgets(s, 79, f)) {
p = strstr(s, pattern);
if (NULL != p) {
fclose(f);
return (atoi(p + strlen(pattern)));
}
}
return -1;
}
static void console_init()
{
int fd;
int tried_devcons = 0;
int tried_vtprimary = 0;
struct serial_struct sr;
char *s;
if ((s = getenv("CONSOLE")) != NULL) {
console = s;
}
#if #cpu(sparc)
/* sparc kernel supports console=tty[ab] parameter which is also
* passed to init, so catch it here */
else if ((s = getenv("console")) != NULL) {
/* remap tty[ab] to /dev/ttyS[01] */
if (strcmp( s, "ttya" )==0)
console = SERIAL_CON0;
else if (strcmp( s, "ttyb" )==0)
console = SERIAL_CON1;
}
#endif
else {
struct vt_stat vt;
static char the_console[13];
console = the_console;
/* 2.2 kernels: identify the real console backend and try to use it */
if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
/* this is a serial console */
snprintf( the_console, sizeof the_console, "/dev/ttyS%d", sr.line );
}
else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
/* this is linux virtual tty */
snprintf( the_console, sizeof the_console, "/dev/tty%d", vt.v_active );
} else {
console = _PATH_CONSOLE;
tried_devcons++;
}
}
while ((fd = open(console, O_RDONLY | O_NONBLOCK)) < 0) {
/* Can't open selected console -- try /dev/console */
if (!tried_devcons) {
tried_devcons++;
console = _PATH_CONSOLE;
continue;
}
/* Can't open selected console -- try vt1 */
if (!tried_vtprimary) {
tried_vtprimary++;
console = VT_PRIMARY;
continue;
}
break;
}
if (fd < 0)
/* Perhaps we should panic here? */
console = "/dev/null";
else {
/* check for serial console and disable logging to tty3 & running a
* shell to tty2 */
if (ioctl(0,TIOCGSERIAL,&sr) == 0) {
message(LOG|CONSOLE, "serial console detected. Disabling 2nd virtual terminal.\r\n", console );
log = NULL;
second_console = NULL;
}
close(fd);
}
message(LOG, "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=0x%x.\n", wpid, status);
}
return wpid;
}
static pid_t run(const char * const* command,
char *terminal, int get_enter)
{
int fd;
pid_t pid;
const char * const* cmd = command+1;
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();
/* Reset signal handlers set for parent process */
signal(SIGUSR1, SIG_DFL);
signal(SIGUSR2, SIG_DFL);
signal(SIGINT, SIG_DFL);
signal(SIGTERM, SIG_DFL);
if ((fd = device_open(terminal, O_RDWR)) < 0) {
message(LOG, "Bummer, can't open %s\r\n", terminal);
exit(-1);
}
dup(fd);
dup(fd);
tcsetpgrp(0, getpgrp());
set_term(0);
if (get_enter==TRUE) {
/*
* 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;
message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
*cmd, getpid(), terminal );
write(1, press_enter, sizeof(press_enter) - 1);
read(0, &c, 1);
}
/* Log the process name and args */
message(LOG|CONSOLE, "Starting pid %d, console %s: '", getpid(), terminal);
while ( *cmd) message(LOG|CONSOLE, "%s ", *cmd++);
message(LOG|CONSOLE, "'\r\n");
/* Now run it. The new program will take over this PID,
* so nothing further in init.c should be run. */
execvp(*command, (char**)command+1);
message(LOG, "Bummer, could not run '%s'\n", command);
exit(-1);
}
return pid;
}
/* Make sure there is enough memory to do something useful. *
* Calls swapon if needed so be sure /proc is mounted. */
static void check_memory()
{
struct stat statbuf;
const char* const swap_on_cmd[] =
{ "/bin/swapon", "swapon", "-a", 0};
if (mem_total() > 3500)
return;
if (stat("/etc/fstab", &statbuf) == 0) {
/* Try to turn on swap */
waitfor(run(swap_on_cmd, log, FALSE));
if (mem_total() < 3500)
goto goodnight;
} else
goto goodnight;
return;
goodnight:
message(CONSOLE, "Sorry, your computer does not have enough memory.\r\n");
while (1) sleep(1);
}
static void shutdown_system(void)
{
const char* const swap_off_cmd[] = { "swapoff", "swapoff", "-a", 0};
const char* const umount_cmd[] = { "umount", "umount", "-a", 0};
#ifndef DEBUG_INIT
/* Allow Ctrl-Alt-Del to reboot system. */
reboot(RB_ENABLE_CAD);
#endif
message(CONSOLE, "\r\nThe system is going down NOW !!\r\n");
sync();
/* Send signals to every process _except_ pid 1 */
message(CONSOLE, "Sending SIGHUP to all processes.\r\n");
#ifndef DEBUG_INIT
kill(-1, SIGHUP);
#endif
sleep(2);
sync();
message(CONSOLE, "Sending SIGKILL to all processes.\r\n");
#ifndef DEBUG_INIT
kill(-1, SIGKILL);
#endif
sleep(1);
message(CONSOLE, "Disabling swap.\r\n");
waitfor(run( swap_off_cmd, console, FALSE));
message(CONSOLE, "Unmounting filesystems.\r\n");
waitfor(run( umount_cmd, console, FALSE));
sync();
if (kernel_version > 0 && kernel_version <= 2 * 65536 + 2 * 256 + 11) {
/* bdflush, kupdate not needed for kernels >2.2.11 */
message(CONSOLE, "Flushing buffers.\r\n");
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");
sync();
#ifndef DEBUG_INIT
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
if (sig == SIGUSR2)
reboot(RB_POWER_OFF);
else
#endif
reboot(RB_HALT_SYSTEM);
#endif
exit(0);
}
static void reboot_signal(int sig)
{
shutdown_system();
message(CONSOLE, "Please stand by while rebooting the system.\r\n");
sync();
#ifndef DEBUG_INIT
reboot(RB_AUTOBOOT);
#endif
exit(0);
}
extern int init_main(int argc, char **argv)
{
int run_rc = FALSE;
int single = FALSE;
int wait_for_enter_tty1 = TRUE;
int wait_for_enter_tty2 = TRUE;
pid_t pid1 = 0;
pid_t pid2 = 0;
struct stat statbuf;
char which_vt1[30];
char which_vt2[30];
const char* const rc_script_command[] = { INITSCRIPT, INITSCRIPT, 0};
const char* const getty1_command[] = { GETTY, GETTY, "38400", which_vt1, 0};
const char* const getty2_command[] = { GETTY, GETTY, "38400", which_vt2, 0};
const char* const shell_command[] = { SHELL, "-" SHELL, 0};
const char* const* tty1_command = shell_command;
const char* const* tty2_command = shell_command;
#ifdef BB_INIT_CMD_IF_RC_SCRIPT_EXITS
const char* const rc_exit_command[] = { "BB_INIT_CMD_IF_RC_SCRIPT_EXITS",
"BB_INIT_CMD_IF_RC_SCRIPT_EXITS", 0 };
#endif
#ifdef DEBUG_INIT
char *hello_msg_format =
"init(%d) started: BusyBox v%s (%s) multi-call binary\r\n";
#else
char *hello_msg_format =
"init started: BusyBox v%s (%s) multi-call binary\r\n";
#endif
#ifndef DEBUG_INIT
/* Expect to be PID 1 iff we are run as init (not linuxrc) */
if (getpid() != 1 && strstr(argv[0], "init")!=NULL ) {
usage( "init\n\nInit is the parent of all processes.\n\n"
"This version of init is designed to be run only by the kernel\n");
}
#endif
/* Set up sig handlers -- be sure to
* clear all of these in run() */
signal(SIGUSR1, 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... */
#ifndef DEBUG_INIT
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 */
putenv(_PATH_STDPATH);
/* Hello world */
#ifndef DEBUG_INIT
message(CONSOLE|LOG, hello_msg_format, BB_VER, BB_BT);
#else
message(CONSOLE|LOG, hello_msg_format, getpid(), BB_VER, BB_BT);
#endif
/* Mount /proc */
if (mount ("proc", "/proc", "proc", 0, 0) == 0) {
message(CONSOLE|LOG, "Mounting /proc: done.\n");
kernel_version = get_kernel_revision();
} else
message(CONSOLE|LOG, "Mounting /proc: failed!\n");
/* Make sure there is enough memory to do something useful. */
check_memory();
/* 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"))) {
single = TRUE;
tty1_command = shell_command;
tty2_command = shell_command;
}
/* Make sure an init script exists before trying to run it */
if (single==FALSE && stat(INITSCRIPT, &statbuf)==0) {
run_rc = TRUE;
wait_for_enter_tty1 = FALSE;
tty1_command = rc_script_command;
}
/* Make sure /sbin/getty exists before trying to run it */
if (stat(GETTY, &statbuf)==0) {
char* where;
/* First do tty2 */
wait_for_enter_tty2 = FALSE;
where = strrchr( second_console, '/');
if ( where != NULL) {
where++;
strncpy( which_vt2, where, sizeof(which_vt2));
}
tty2_command = getty2_command;
/* Check on hooking a getty onto tty1 */
if (run_rc == FALSE && single==FALSE) {
wait_for_enter_tty1 = FALSE;
where = strrchr( console, '/');
if ( where != NULL) {
where++;
strncpy( which_vt1, where, sizeof(which_vt1));
}
tty1_command = getty1_command;
}
}
/* Ok, now launch the tty1_command and tty2_command */
for (;;) {
pid_t wpid;
int status;
if (pid1 == 0 && tty1_command) {
pid1 = run(tty1_command, console, wait_for_enter_tty1);
}
#ifdef BB_FEATURE_INIT_SECOND_CONSOLE
if (pid2 == 0 && tty2_command && second_console) {
pid2 = run(tty2_command, second_console, wait_for_enter_tty2);
}
#endif
wpid = wait(&status);
if (wpid > 0 ) {
message(LOG, "pid %d exited, status=%x.\n", wpid, status);
}
/* Don't respawn init script if it exits */
if (wpid == pid1) {
if (run_rc == FALSE) {
pid1 = 0;
}
#ifdef BB_INIT_CMD_IF_RC_SCRIPT_EXITS
else {
pid1 = 0;
run_rc=FALSE;
wait_for_enter_tty1=TRUE;
tty1_command=rc_exit_command;
}
#endif
}
#ifdef BB_FEATURE_INIT_SECOND_CONSOLE
if (wpid == pid2) {
pid2 = 0;
}
#endif
sleep(1);
}
}