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busybox/init/init.c
Eric Andersen 0d4e51d390 Prevent init from potentially using already freed memory when 
deleting an initAction, fixing a bug pointed out by Andreas Neuhaus
 -Erik
2001-03-15 19:18:21 +00:00

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/* vi: set sw=4 ts=4: */
/*
* 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
*
*/
/* Turn this on to disable all the dangerous
rebooting stuff when debugging.
#define DEBUG_INIT
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <paths.h>
#include <signal.h>
#include <stdarg.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <limits.h>
#include <sys/fcntl.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "busybox.h"
#define bb_need_full_version
#define BB_DECLARE_EXTERN
#include "messages.c"
#ifdef BB_SYSLOGD
# include <sys/syslog.h>
#endif
/* From <linux/vt.h> */
struct vt_stat {
unsigned short v_active; /* active vt */
unsigned short v_signal; /* signal to send */
unsigned short v_state; /* vt bitmask */
};
static const int VT_GETSTATE = 0x5603; /* get global vt state info */
/* From <linux/serial.h> */
struct serial_struct {
int type;
int line;
int port;
int irq;
int flags;
int xmit_fifo_size;
int custom_divisor;
int baud_base;
unsigned short close_delay;
char reserved_char[2];
int hub6;
unsigned short closing_wait; /* time to wait before closing */
unsigned short closing_wait2; /* no longer used... */
int reserved[4];
};
#ifndef RB_HALT_SYSTEM
static const int RB_HALT_SYSTEM = 0xcdef0123;
static const int RB_ENABLE_CAD = 0x89abcdef;
static const int RB_DISABLE_CAD = 0;
#define RB_POWER_OFF 0x4321fedc
static const int RB_AUTOBOOT = 0x01234567;
#if defined(__GLIBC__) || defined (__UCLIBC__)
#include <sys/reboot.h>
#define init_reboot(magic) reboot(magic)
#else
#define init_reboot(magic) reboot(0xfee1dead, 672274793, magic)
#endif
#endif
#ifndef _PATH_STDPATH
#define _PATH_STDPATH "/usr/bin:/bin:/usr/sbin:/sbin"
#endif
#if defined BB_FEATURE_INIT_COREDUMPS
/*
* When a file named CORE_ENABLE_FLAG_FILE exists, setrlimit is called
* before processes are spawned to set core file size as unlimited.
* This is for debugging only. Don't use this is production, unless
* you want core dumps lying about....
*/
#define CORE_ENABLE_FLAG_FILE "/.init_enable_core"
#include <sys/resource.h>
#include <sys/time.h>
#endif
#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
#if defined(__GLIBC__)
#include <sys/kdaemon.h>
#else
#include <sys/syscall.h>
#include <linux/unistd.h>
static _syscall2(int, bdflush, int, func, int, data);
#endif /* __GLIBC__ */
#define VT_PRIMARY "/dev/tty1" /* Primary virtual console */
#define VT_SECONDARY "/dev/tty2" /* Virtual console */
#define VT_THIRD "/dev/tty3" /* Virtual console */
#define VT_FOURTH "/dev/tty4" /* Virtual console */
#define VT_LOG "/dev/tty5" /* Virtual console */
#define SERIAL_CON0 "/dev/ttyS0" /* Primary serial console */
#define SERIAL_CON1 "/dev/ttyS1" /* Serial console */
#define SHELL "-/bin/sh" /* Default shell */
#define INITTAB "/etc/inittab" /* inittab file location */
#ifndef INIT_SCRIPT
#define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
#endif
#define MAXENV 16 /* Number of env. vars */
//static const int MAXENV = 16; /* Number of env. vars */
static const int LOG = 0x1;
static const int CONSOLE = 0x2;
/* Allowed init action types */
typedef enum {
SYSINIT = 1,
RESPAWN,
ASKFIRST,
WAIT,
ONCE,
CTRLALTDEL
} initActionEnum;
/* A mapping between "inittab" action name strings and action type codes. */
typedef struct initActionType {
const char *name;
initActionEnum action;
} initActionType;
static const struct initActionType actions[] = {
{"sysinit", SYSINIT},
{"respawn", RESPAWN},
{"askfirst", ASKFIRST},
{"wait", WAIT},
{"once", ONCE},
{"ctrlaltdel", CTRLALTDEL},
{0, 0}
};
/* Set up a linked list of initActions, to be read from inittab */
typedef struct initActionTag initAction;
struct initActionTag {
pid_t pid;
char process[256];
char console[256];
initAction *nextPtr;
initActionEnum action;
};
static initAction *initActionList = NULL;
static char *secondConsole = VT_SECONDARY;
static char *thirdConsole = VT_THIRD;
static char *fourthConsole = VT_FOURTH;
static char *log = VT_LOG;
static int kernelVersion = 0;
static char termType[32] = "TERM=linux";
static char console[32] = _PATH_CONSOLE;
static void delete_initAction(initAction * action);
/* Print a message to the specified device.
* Device may be bitwise-or'd from LOG | CONSOLE */
static void message(int device, char *fmt, ...)
__attribute__ ((format (printf, 2, 3)));
static void message(int device, char *fmt, ...)
{
va_list arguments;
int fd;
#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);
openlog(applet_name, 0, LOG_USER);
syslog(LOG_USER|LOG_INFO, msg);
closelog();
}
#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 = -2;
fprintf(stderr, "Bummer, can't write to log on %s!\r\n", log);
log = NULL;
device = CONSOLE;
}
}
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);
va_end(arguments);
}
}
}
/* Set terminal settings to reasonable defaults */
static void set_term(int fd)
{
struct termios tty;
tcgetattr(fd, &tty);
/* set control chars */
tty.c_cc[VINTR] = 3; /* C-c */
tty.c_cc[VQUIT] = 28; /* C-\ */
tty.c_cc[VERASE] = 127; /* C-? */
tty.c_cc[VKILL] = 21; /* C-u */
tty.c_cc[VEOF] = 4; /* C-d */
tty.c_cc[VSTART] = 17; /* C-q */
tty.c_cc[VSTOP] = 19; /* C-s */
tty.c_cc[VSUSP] = 26; /* C-z */
/* 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?
Units are kBytes to avoid overflow on 4GB machines */
static int check_free_memory()
{
struct sysinfo info;
unsigned int result, u, s=10;
if (sysinfo(&info) != 0) {
perror_msg("Error checking free memory");
return -1;
}
/* Kernels 2.0.x and 2.2.x return info.mem_unit==0 with values in bytes.
* Kernels 2.4.0 return info.mem_unit in bytes. */
u = info.mem_unit;
if (u==0) u=1;
while ( (u&1) == 0 && s > 0 ) { u>>=1; s--; }
result = (info.totalram>>s) + (info.totalswap>>s);
result = result*u;
if (result < 0) result = INT_MAX;
return result;
}
static void console_init()
{
int fd;
int tried_devcons = 0;
int tried_vtprimary = 0;
struct vt_stat vt;
struct serial_struct sr;
char *s;
if ((s = getenv("TERM")) != NULL) {
snprintf(termType, sizeof(termType) - 1, "TERM=%s", s);
}
if ((s = getenv("CONSOLE")) != NULL) {
snprintf(console, sizeof(console) - 1, "%s", 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)
snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON0);
else if (strcmp(s, "ttyb") == 0)
snprintf(console, sizeof(console) - 1, "%s", SERIAL_CON1);
}
#endif
else {
/* 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(console, sizeof(console) - 1, "/dev/ttyS%d", sr.line);
} else if (ioctl(0, VT_GETSTATE, &vt) == 0) {
/* this is linux virtual tty */
snprintf(console, sizeof(console) - 1, "/dev/tty%d",
vt.v_active);
} else {
snprintf(console, sizeof(console) - 1, "%s", _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++;
snprintf(console, sizeof(console) - 1, "%s", _PATH_CONSOLE);
continue;
}
/* Can't open selected console -- try vt1 */
if (!tried_vtprimary) {
tried_vtprimary++;
snprintf(console, sizeof(console) - 1, "%s", VT_PRIMARY);
continue;
}
break;
}
if (fd < 0) {
/* Perhaps we should panic here? */
snprintf(console, sizeof(console) - 1, "/dev/null");
} else {
/* check for serial console and disable logging to tty5 & running a
* shell to tty2-4 */
if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
log = NULL;
secondConsole = NULL;
thirdConsole = NULL;
fourthConsole = NULL;
/* Force the TERM setting to vt102 for serial console --
* iff TERM is set to linux (the default) */
if (strcmp( termType, "TERM=linux" ) == 0)
snprintf(termType, sizeof(termType) - 1, "TERM=vt102");
message(LOG | CONSOLE,
"serial console detected. Disabling virtual terminals.\r\n");
}
close(fd);
}
message(LOG, "console=%s\n", console);
}
static pid_t run(char *command, char *terminal, int get_enter)
{
int i=0, j=0;
int fd;
pid_t pid;
char *tmpCmd;
char *cmd[255], *cmdpath;
char buf[255];
static const char press_enter[] =
#ifdef CUSTOMIZED_BANNER
#include CUSTOMIZED_BANNER
#endif
"\nPlease press Enter to activate this console. ";
char *environment[MAXENV+1] = {
"HOME=/",
"PATH=/usr/bin:/bin:/usr/sbin:/sbin",
"SHELL=/bin/sh",
termType,
"USER=root"
};
while (environment[i]) i++;
while ((environ[j]) && (i < MAXENV)) {
if (strncmp(environ[j], "TERM=", 5))
environment[i++] = environ[j];
j++;
}
if ((pid = fork()) == 0) {
/* Clean up */
ioctl(0, TIOCNOTTY, 0);
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);
signal(SIGHUP, SIG_DFL);
if ((fd = device_open(terminal, O_RDWR)) < 0) {
struct stat statBuf;
if (stat(terminal, &statBuf) != 0) {
message(LOG | CONSOLE, "device '%s' does not exist.\n",
terminal);
exit(1);
}
message(LOG | CONSOLE, "Bummer, can't open %s\r\n", terminal);
exit(1);
}
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
ioctl(0, TIOCSCTTY, 1);
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.
*/
#ifdef DEBUG_INIT
message(LOG, "Waiting for enter to start '%s' (pid %d, console %s)\r\n",
command, getpid(), terminal);
#endif
write(fileno(stdout), press_enter, sizeof(press_enter) - 1);
getc(stdin);
}
#ifdef DEBUG_INIT
/* Log the process name and args */
message(LOG, "Starting pid %d, console %s: '%s'\r\n",
getpid(), terminal, command);
#endif
/* See if any special /bin/sh requiring characters are present */
if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
cmd[0] = SHELL;
cmd[1] = "-c";
strcpy(buf, "exec ");
strncat(buf, command, sizeof(buf) - strlen(buf) - 1);
cmd[2] = buf;
cmd[3] = NULL;
} else {
/* Convert command (char*) into cmd (char**, one word per string) */
for (tmpCmd = command, i = 0;
(tmpCmd = strsep(&command, " \t")) != NULL;) {
if (*tmpCmd != '\0') {
cmd[i] = tmpCmd;
tmpCmd++;
i++;
}
}
cmd[i] = NULL;
}
cmdpath = cmd[0];
/*
Interactive shells want to see a dash in argv[0]. This
typically is handled by login, argv will be setup this
way if a dash appears at the front of the command path
(like "-/bin/sh").
*/
if (*cmdpath == '-') {
char *s;
/* skip over the dash */
++cmdpath;
/* find the last component in the command pathname */
s = get_last_path_component(cmdpath);
/* make a new argv[0] */
if ((cmd[0] = malloc(strlen(s)+2)) == NULL) {
message(LOG | CONSOLE, "malloc failed");
cmd[0] = cmdpath;
} else {
cmd[0][0] = '-';
strcpy(cmd[0]+1, s);
}
}
#if defined BB_FEATURE_INIT_COREDUMPS
{
struct stat sb;
if (stat (CORE_ENABLE_FLAG_FILE, &sb) == 0) {
struct rlimit limit;
limit.rlim_cur = RLIM_INFINITY;
limit.rlim_max = RLIM_INFINITY;
setrlimit(RLIMIT_CORE, &limit);
}
}
#endif
/* Now run it. The new program will take over this PID,
* so nothing further in init.c should be run. */
execve(cmdpath, cmd, environment);
/* We're still here? Some error happened. */
message(LOG | CONSOLE, "Bummer, could not run '%s': %s\n", cmdpath,
strerror(errno));
exit(-1);
}
return pid;
}
static int waitfor(char *command, char *terminal, int get_enter)
{
int status, wpid;
int pid = run(command, terminal, get_enter);
while (1) {
wpid = wait(&status);
if (wpid > 0 && wpid != pid) {
continue;
}
if (wpid == pid)
break;
}
return wpid;
}
/* Make sure there is enough memory to do something useful. *
* Calls "swapon -a" if needed so be sure /etc/fstab is present... */
static void check_memory()
{
struct stat statBuf;
if (check_free_memory() > 1000)
return;
if (stat("/etc/fstab", &statBuf) == 0) {
/* swapon -a requires /proc typically */
waitfor("mount proc /proc -t proc", console, FALSE);
/* Try to turn on swap */
waitfor("swapon -a", console, FALSE);
if (check_free_memory() < 1000)
goto goodnight;
} else
goto goodnight;
return;
goodnight:
message(CONSOLE,
"Sorry, your computer does not have enough memory.\r\n");
while (1)
sleep(1);
}
/* Run all commands to be run right before halt/reboot */
static void run_lastAction(void)
{
initAction *a, *tmp;
for (a = tmp = initActionList; a; a = tmp = tmp->nextPtr) {
if (a->action == CTRLALTDEL) {
waitfor(a->process, a->console, FALSE);
delete_initAction(a);
}
}
}
#ifndef DEBUG_INIT
static void shutdown_system(void)
{
/* first disable our SIGHUP signal */
signal(SIGHUP, SIG_DFL);
/* Allow Ctrl-Alt-Del to reboot system. */
init_reboot(RB_ENABLE_CAD);
message(CONSOLE|LOG, "\r\nThe system is going down NOW !!\r\n");
sync();
/* Send signals to every process _except_ pid 1 */
message(CONSOLE|LOG, "Sending SIGTERM to all processes.\r\n");
kill(-1, SIGTERM);
sleep(1);
sync();
message(CONSOLE|LOG, "Sending SIGKILL to all processes.\r\n");
kill(-1, SIGKILL);
sleep(1);
/* run everything to be run at "ctrlaltdel" */
run_lastAction();
sync();
if (kernelVersion > 0 && kernelVersion <= KERNEL_VERSION(2,2,11)) {
/* bdflush, kupdate not needed for kernels >2.2.11 */
bdflush(1, 0);
sync();
}
}
static void halt_signal(int sig)
{
shutdown_system();
message(CONSOLE|LOG,
"The system is halted. Press %s or turn off power\r\n",
(secondConsole == NULL) /* serial console */
? "Reset" : "CTRL-ALT-DEL");
sync();
/* allow time for last message to reach serial console */
sleep(2);
if (sig == SIGUSR2 && kernelVersion >= KERNEL_VERSION(2,2,0))
init_reboot(RB_POWER_OFF);
else
init_reboot(RB_HALT_SYSTEM);
exit(0);
}
static void reboot_signal(int sig)
{
shutdown_system();
message(CONSOLE|LOG, "Please stand by while rebooting the system.\r\n");
sync();
/* allow time for last message to reach serial console */
sleep(2);
init_reboot(RB_AUTOBOOT);
exit(0);
}
#endif /* ! DEBUG_INIT */
static void new_initAction(initActionEnum action, char *process, char *cons)
{
initAction *newAction;
if (*cons == '\0')
cons = console;
/* If BusyBox detects that a serial console is in use,
* then entries not refering to the console or null devices will _not_ be run.
* The exception to this rule is the null device.
*/
if (secondConsole == NULL && strcmp(cons, console)
&& strcmp(cons, "/dev/null"))
return;
newAction = calloc((size_t) (1), sizeof(initAction));
if (!newAction) {
message(LOG | CONSOLE, "Memory allocation failure\n");
while (1)
sleep(1);
}
newAction->nextPtr = initActionList;
initActionList = newAction;
strncpy(newAction->process, process, 255);
newAction->action = action;
strncpy(newAction->console, cons, 255);
newAction->pid = 0;
// message(LOG|CONSOLE, "process='%s' action='%d' console='%s'\n",
// newAction->process, newAction->action, newAction->console);
}
static void delete_initAction(initAction * action)
{
initAction *a, *b = NULL;
for (a = initActionList; a; b = a, a = a->nextPtr) {
if (a == action) {
if (b == NULL) {
initActionList = a->nextPtr;
} else {
b->nextPtr = a->nextPtr;
}
free(a);
break;
}
}
}
/* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
* then parse_inittab() simply adds in some default
* actions(i.e runs INIT_SCRIPT and then starts a pair
* of "askfirst" shells). If BB_FEATURE_USE_INITTAB
* _is_ defined, but /etc/inittab is missing, this
* results in the same set of default behaviors.
* */
static void parse_inittab(void)
{
#ifdef BB_FEATURE_USE_INITTAB
FILE *file;
char buf[256], lineAsRead[256], tmpConsole[256];
char *id, *runlev, *action, *process, *eol;
const struct initActionType *a = actions;
int foundIt;
file = fopen(INITTAB, "r");
if (file == NULL) {
/* No inittab file -- set up some default behavior */
#endif
/* Swapoff on halt/reboot */
new_initAction(CTRLALTDEL, "/sbin/swapoff -a", console);
/* Umount all filesystems on halt/reboot */
new_initAction(CTRLALTDEL, "/bin/umount -a -r", console);
/* Askfirst shell on tty1 */
new_initAction(ASKFIRST, SHELL, console);
/* Askfirst shell on tty2 */
if (secondConsole != NULL)
new_initAction(ASKFIRST, SHELL, secondConsole);
/* Askfirst shell on tty3 */
if (thirdConsole != NULL)
new_initAction(ASKFIRST, SHELL, thirdConsole);
/* Askfirst shell on tty4 */
if (fourthConsole != NULL)
new_initAction(ASKFIRST, SHELL, fourthConsole);
/* sysinit */
new_initAction(SYSINIT, INIT_SCRIPT, console);
return;
#ifdef BB_FEATURE_USE_INITTAB
}
while (fgets(buf, 255, file) != NULL) {
foundIt = FALSE;
/* Skip leading spaces */
for (id = buf; *id == ' ' || *id == '\t'; id++);
/* Skip the line if it's a comment */
if (*id == '#' || *id == '\n')
continue;
/* Trim the trailing \n */
eol = strrchr(id, '\n');
if (eol != NULL)
*eol = '\0';
/* Keep a copy around for posterity's sake (and error msgs) */
strcpy(lineAsRead, buf);
/* Separate the ID field from the runlevels */
runlev = strchr(id, ':');
if (runlev == NULL || *(runlev + 1) == '\0') {
message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
continue;
} else {
*runlev = '\0';
++runlev;
}
/* Separate the runlevels from the action */
action = strchr(runlev, ':');
if (action == NULL || *(action + 1) == '\0') {
message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
continue;
} else {
*action = '\0';
++action;
}
/* Separate the action from the process */
process = strchr(action, ':');
if (process == NULL || *(process + 1) == '\0') {
message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
continue;
} else {
*process = '\0';
++process;
}
/* Ok, now process it */
a = actions;
while (a->name != 0) {
if (strcmp(a->name, action) == 0) {
if (*id != '\0') {
strcpy(tmpConsole, "/dev/");
strncat(tmpConsole, id, 200);
id = tmpConsole;
}
new_initAction(a->action, process, id);
foundIt = TRUE;
}
a++;
}
if (foundIt == TRUE)
continue;
else {
/* Choke on an unknown action */
message(LOG | CONSOLE, "Bad inittab entry: %s\n", lineAsRead);
}
}
return;
#endif /* BB_FEATURE_USE_INITTAB */
}
extern int init_main(int argc, char **argv)
{
initAction *a, *tmp;
pid_t wpid;
int status;
#ifndef DEBUG_INIT
/* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
if (getpid() != 1
#ifdef BB_FEATURE_LINUXRC
&& strstr(applet_name, "linuxrc") == NULL
#endif
)
{
show_usage();
}
/* Set up sig handlers -- be sure to
* clear all of these in run() */
signal(SIGUSR1, halt_signal);
signal(SIGUSR2, halt_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... */
init_reboot(RB_DISABLE_CAD);
#endif
/* Figure out what kernel this is running */
kernelVersion = get_kernel_revision();
/* 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);
chdir("/");
setsid();
/* Make sure PATH is set to something sane */
putenv("PATH="_PATH_STDPATH);
/* Hello world */
#ifndef DEBUG_INIT
message(
#if ! defined BB_FEATURE_EXTRA_QUIET
CONSOLE|
#endif
LOG,
"init started: %s\r\n", full_version);
#else
message(
#if ! defined BB_FEATURE_EXTRA_QUIET
CONSOLE|
#endif
LOG,
"init(%d) started: %s\r\n", getpid(), full_version);
#endif
/* 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"))) {
/* Ask first then start a shell on tty2-4 */
if (secondConsole != NULL)
new_initAction(ASKFIRST, SHELL, secondConsole);
if (thirdConsole != NULL)
new_initAction(ASKFIRST, SHELL, thirdConsole);
if (fourthConsole != NULL)
new_initAction(ASKFIRST, SHELL, fourthConsole);
/* Start a shell on tty1 */
new_initAction(RESPAWN, SHELL, console);
} else {
/* Not in single user mode -- see what inittab says */
/* NOTE that if BB_FEATURE_USE_INITTAB is NOT defined,
* then parse_inittab() simply adds in some default
* actions(i.e runs INIT_SCRIPT and then starts a pair
* of "askfirst" shells */
parse_inittab();
}
/* Fix up argv[0] to be certain we claim to be init */
argv[0]="init";
if (argc > 1)
argv[1][0]=0;
/* Now run everything that needs to be run */
/* First run the sysinit command */
for (a = tmp = initActionList; a; a = tmp = tmp->nextPtr) {
if (a->action == SYSINIT) {
waitfor(a->process, a->console, FALSE);
/* Now remove the "sysinit" entry from the list */
delete_initAction(a);
}
}
/* Next run anything that wants to block */
for (a = tmp = initActionList; a; a = tmp = tmp->nextPtr) {
if (a->action == WAIT) {
waitfor(a->process, a->console, FALSE);
/* Now remove the "wait" entry from the list */
delete_initAction(a);
}
}
/* Next run anything to be run only once */
for (a = tmp = initActionList; a; a = tmp = tmp->nextPtr) {
if (a->action == ONCE) {
run(a->process, a->console, FALSE);
/* Now remove the "once" entry from the list */
delete_initAction(a);
}
}
/* If there is nothing else to do, stop */
if (initActionList == NULL) {
message(LOG | CONSOLE,
"No more tasks for init -- sleeping forever.\n");
while (1)
sleep(1);
}
/* Now run the looping stuff for the rest of forever */
while (1) {
for (a = initActionList; a; a = a->nextPtr) {
/* Only run stuff with pid==0. If they have
* a pid, that means they are still running */
if (a->pid == 0) {
switch (a->action) {
case RESPAWN:
/* run the respawn stuff */
a->pid = run(a->process, a->console, FALSE);
break;
case ASKFIRST:
/* run the askfirst stuff */
a->pid = run(a->process, a->console, TRUE);
break;
/* silence the compiler's incessant whining */
default:
break;
}
}
}
/* Wait for a child process to exit */
wpid = wait(&status);
if (wpid > 0) {
/* Find out who died and clean up their corpse */
for (a = initActionList; a; a = a->nextPtr) {
if (a->pid == wpid) {
a->pid = 0;
message(LOG,
"Process '%s' (pid %d) exited. Scheduling it for restart.\n",
a->process, wpid);
}
}
}
sleep(1);
}
}
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/
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