busybox/init/init.c
Denis Vlasenko 3f165fa5b3 libbb: introduce and use sigprocmask_allsigs and sigaction_set.
libbb: rename sig_pause to wait_for_any_sig.
2008-03-17 08:29:08 +00:00

977 lines
25 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Mini init implementation for busybox
*
* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* Adjusted by so many folks, it's impossible to keep track.
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
#include <syslog.h>
#include <paths.h>
#include <sys/reboot.h>
#define COMMAND_SIZE 256
#define CONSOLE_NAME_SIZE 32
#define MAXENV 16 /* Number of env. vars */
/*
* 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>
#define INITTAB "/etc/inittab" /* inittab file location */
#ifndef INIT_SCRIPT
#define INIT_SCRIPT "/etc/init.d/rcS" /* Default sysinit script. */
#endif
/* Allowed init action types */
#define SYSINIT 0x001
#define RESPAWN 0x002
#define ASKFIRST 0x004
#define WAIT 0x008
#define ONCE 0x010
#define CTRLALTDEL 0x020
#define SHUTDOWN 0x040
#define RESTART 0x080
#define STR_SYSINIT "\x01"
#define STR_RESPAWN "\x02"
#define STR_ASKFIRST "\x04"
#define STR_WAIT "\x08"
#define STR_ONCE "\x10"
#define STR_CTRLALTDEL "\x20"
#define STR_SHUTDOWN "\x40"
#define STR_RESTART "\x80"
/* Set up a linked list of init_actions, to be read from inittab */
struct init_action {
struct init_action *next;
pid_t pid;
uint8_t action_type;
char terminal[CONSOLE_NAME_SIZE];
char command[COMMAND_SIZE];
};
/* Static variables */
static struct init_action *init_action_list = NULL;
static const char *log_console = VC_5;
static sig_atomic_t got_cont = 0;
enum {
L_LOG = 0x1,
L_CONSOLE = 0x2,
#if ENABLE_FEATURE_EXTRA_QUIET
MAYBE_CONSOLE = 0x0,
#else
MAYBE_CONSOLE = L_CONSOLE,
#endif
#ifndef RB_HALT_SYSTEM
RB_HALT_SYSTEM = 0xcdef0123, /* FIXME: this overflows enum */
RB_ENABLE_CAD = 0x89abcdef,
RB_DISABLE_CAD = 0,
RB_POWER_OFF = 0x4321fedc,
RB_AUTOBOOT = 0x01234567,
#endif
};
static const char *const environment[] = {
"HOME=/",
bb_PATH_root_path,
"SHELL=/bin/sh",
"USER=root",
NULL
};
/* Function prototypes */
static void delete_init_action(struct init_action *a);
static void halt_reboot_pwoff(int sig) ATTRIBUTE_NORETURN;
static void waitfor(pid_t pid)
{
/* waitfor(run(x)): protect against failed fork inside run() */
if (pid <= 0)
return;
/* Wait for any child (prevent zombies from exiting orphaned processes)
* but exit the loop only when specified one has exited. */
while (wait(NULL) != pid)
continue;
}
static void loop_forever(void) ATTRIBUTE_NORETURN;
static void loop_forever(void)
{
while (1)
sleep(1);
}
/* Print a message to the specified device.
* "where" may be bitwise-or'd from L_LOG | L_CONSOLE
* NB: careful, we can be called after vfork!
*/
#define messageD(...) do { if (ENABLE_DEBUG_INIT) message(__VA_ARGS__); } while (0)
static void message(int where, const char *fmt, ...)
__attribute__ ((format(printf, 2, 3)));
static void message(int where, const char *fmt, ...)
{
static int log_fd = -1;
va_list arguments;
int l;
char msg[128];
msg[0] = '\r';
va_start(arguments, fmt);
vsnprintf(msg + 1, sizeof(msg) - 2, fmt, arguments);
va_end(arguments);
msg[sizeof(msg) - 2] = '\0';
l = strlen(msg);
if (ENABLE_FEATURE_INIT_SYSLOG) {
/* Log the message to syslogd */
if (where & L_LOG) {
/* don't out "\r" */
openlog(applet_name, 0, LOG_DAEMON);
syslog(LOG_INFO, "init: %s", msg + 1);
closelog();
}
msg[l++] = '\n';
msg[l] = '\0';
} else {
msg[l++] = '\n';
msg[l] = '\0';
/* Take full control of the log tty, and never close it.
* It's mine, all mine! Muhahahaha! */
if (log_fd < 0) {
if (!log_console) {
log_fd = 2;
} else {
log_fd = device_open(log_console, O_WRONLY | O_NONBLOCK | O_NOCTTY);
if (log_fd < 0) {
bb_error_msg("can't log to %s", log_console);
where = L_CONSOLE;
} else {
close_on_exec_on(log_fd);
}
}
}
if (where & L_LOG) {
full_write(log_fd, msg, l);
if (log_fd == 2)
return; /* don't print dup messages */
}
}
if (where & L_CONSOLE) {
/* Send console messages to console so people will see them. */
full_write(2, msg, l);
}
}
/* From <linux/serial.h> */
struct serial_struct {
int type;
int line;
unsigned int port;
int irq;
int flags;
int xmit_fifo_size;
int custom_divisor;
int baud_base;
unsigned short close_delay;
char io_type;
char reserved_char[1];
int hub6;
unsigned short closing_wait; /* time to wait before closing */
unsigned short closing_wait2; /* no longer used... */
unsigned char *iomem_base;
unsigned short iomem_reg_shift;
unsigned int port_high;
unsigned long iomap_base; /* cookie passed into ioremap */
int reserved[1];
/* Paranoia (imagine 64bit kernel overwriting 32bit userspace stack) */
uint32_t bbox_reserved[16];
};
static void console_init(void)
{
struct serial_struct sr;
char *s;
s = getenv("CONSOLE");
if (!s) s = getenv("console");
if (s) {
int fd = open(s, O_RDWR | O_NONBLOCK | O_NOCTTY);
if (fd >= 0) {
dup2(fd, 0);
dup2(fd, 1);
dup2(fd, 2);
while (fd > 2) close(fd--);
}
messageD(L_LOG, "console='%s'", s);
} else {
/* Make sure fd 0,1,2 are not closed */
bb_sanitize_stdio();
}
s = getenv("TERM");
if (ioctl(0, TIOCGSERIAL, &sr) == 0) {
/* Force the TERM setting to vt102 for serial console
* if TERM is set to linux (the default) */
if (!s || strcmp(s, "linux") == 0)
putenv((char*)"TERM=vt102");
if (!ENABLE_FEATURE_INIT_SYSLOG)
log_console = NULL;
} else if (!s)
putenv((char*)"TERM=linux");
}
/* Set terminal settings to reasonable defaults.
* NB: careful, we can be called after vfork! */
static void set_sane_term(void)
{
struct termios tty;
tcgetattr(STDIN_FILENO, &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 |= CREAD | 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(STDIN_FILENO, TCSANOW, &tty);
}
/* Open the new terminal device.
* NB: careful, we can be called after vfork! */
static void open_stdio_to_tty(const char* tty_name, int exit_on_failure)
{
/* empty tty_name means "use init's tty", else... */
if (tty_name[0]) {
int fd;
close(0);
/* fd can be only < 0 or 0: */
fd = device_open(tty_name, O_RDWR);
if (fd) {
message(L_LOG | L_CONSOLE, "Can't open %s: %s",
tty_name, strerror(errno));
if (exit_on_failure)
_exit(1);
if (ENABLE_DEBUG_INIT)
_exit(2);
/* NB: we don't reach this if we were called after vfork.
* Thus halt_reboot_pwoff() itself need not be vfork-safe. */
halt_reboot_pwoff(SIGUSR1); /* halt the system */
}
dup2(0, 1);
dup2(0, 2);
}
set_sane_term();
}
/* Wrapper around exec:
* Takes string (max COMMAND_SIZE chars).
* If chars like '>' detected, execs '[-]/bin/sh -c "exec ......."'.
* Otherwise splits words on whitespace, deals with leading dash,
* and uses plain exec().
* NB: careful, we can be called after vfork!
*/
static void init_exec(const char *command)
{
char *cmd[COMMAND_SIZE / 2];
char buf[COMMAND_SIZE + 6]; /* COMMAND_SIZE+strlen("exec ")+1 */
int dash = (command[0] == '-' /* maybe? && command[1] == '/' */);
/* See if any special /bin/sh requiring characters are present */
if (strpbrk(command, "~`!$^&*()=|\\{}[];\"'<>?") != NULL) {
strcpy(buf, "exec ");
strcpy(buf + 5, command + dash); /* excluding "-" */
/* NB: LIBBB_DEFAULT_LOGIN_SHELL define has leading dash */
cmd[0] = (char*)(LIBBB_DEFAULT_LOGIN_SHELL + !dash);
cmd[1] = (char*)"-c";
cmd[2] = buf;
cmd[3] = NULL;
} else {
/* Convert command (char*) into cmd (char**, one word per string) */
char *word, *next;
int i = 0;
next = strcpy(buf, command); /* including "-" */
while ((word = strsep(&next, " \t")) != NULL) {
if (*word != '\0') { /* not two spaces/tabs together? */
cmd[i] = word;
i++;
}
}
cmd[i] = NULL;
}
/* If we saw leading "-", it is interactive shell.
* Try harder to give it a controlling tty.
* And skip "-" in actual exec call. */
if (dash) {
/* _Attempt_ to make stdin a controlling tty. */
if (ENABLE_FEATURE_INIT_SCTTY)
ioctl(STDIN_FILENO, TIOCSCTTY, 0 /*only try, don't steal*/);
}
BB_EXECVP(cmd[0] + dash, cmd);
message(L_LOG | L_CONSOLE, "Cannot run '%s': %s",
cmd[0], strerror(errno));
/* returns if execvp fails */
}
/* Used only by run_actions */
static pid_t run(const struct init_action *a)
{
pid_t pid;
sigset_t nmask, omask;
/* Block sigchild while forking (why?) */
sigemptyset(&nmask);
sigaddset(&nmask, SIGCHLD);
sigprocmask(SIG_BLOCK, &nmask, &omask);
pid = vfork();
sigprocmask(SIG_SETMASK, &omask, NULL);
if (pid < 0)
message(L_LOG | L_CONSOLE, "Can't fork");
if (pid)
return pid;
/* Child */
/* Reset signal handlers that were set by the parent process */
bb_signals(0
+ (1 << SIGUSR1)
+ (1 << SIGUSR2)
+ (1 << SIGINT)
+ (1 << SIGTERM)
+ (1 << SIGHUP)
+ (1 << SIGQUIT)
+ (1 << SIGCONT)
+ (1 << SIGSTOP)
+ (1 << SIGTSTP)
, SIG_DFL);
/* Create a new session and make ourself the process
* group leader */
setsid();
/* Open the new terminal device */
open_stdio_to_tty(a->terminal, 1 /* - exit if open fails */);
// NB: do not enable unless you change vfork to fork above
#ifdef BUT_RUN_ACTIONS_ALREADY_DOES_WAITING
/* If the init Action requires us to wait, then force the
* supplied terminal to be the controlling tty. */
if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
/* Now fork off another process to just hang around */
pid = fork();
if (pid < 0) {
message(L_LOG | L_CONSOLE, "Can't fork");
_exit(1);
}
if (pid > 0) {
/* Parent - wait till the child is done */
bb_signals(0
+ (1 << SIGINT)
+ (1 << SIGTSTP)
+ (1 << SIGQUIT)
, SIG_IGN);
signal(SIGCHLD, SIG_DFL);
waitfor(pid);
/* See if stealing the controlling tty back is necessary */
if (tcgetpgrp(0) != getpid())
_exit(0);
/* Use a temporary process to steal the controlling tty. */
pid = fork();
if (pid < 0) {
message(L_LOG | L_CONSOLE, "Can't fork");
_exit(1);
}
if (pid == 0) {
setsid();
ioctl(0, TIOCSCTTY, 1);
_exit(0);
}
waitfor(pid);
_exit(0);
}
/* Child - fall though to actually execute things */
}
#endif
/* NB: on NOMMU we can't wait for input in child */
if (BB_MMU && (a->action_type & ASKFIRST)) {
static const char press_enter[] ALIGN1 =
#ifdef CUSTOMIZED_BANNER
#include CUSTOMIZED_BANNER
#endif
"\nPlease press Enter to activate this console. ";
char c;
/*
* 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.
*/
messageD(L_LOG, "waiting for enter to start '%s'"
"(pid %d, tty '%s')\n",
a->command, getpid(), a->terminal);
full_write(1, press_enter, sizeof(press_enter) - 1);
while (safe_read(0, &c, 1) == 1 && c != '\n')
continue;
}
if (ENABLE_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);
}
}
/* Log the process name and args */
message(L_LOG, "starting pid %d, tty '%s': '%s'",
getpid(), a->terminal, a->command);
/* Now run it. The new program will take over this PID,
* so nothing further in init.c should be run. */
init_exec(a->command);
/* We're still here? Some error happened. */
_exit(-1);
}
/* Run all commands of a particular type */
static void run_actions(int action_type)
{
struct init_action *a, *tmp;
for (a = init_action_list; a; a = tmp) {
tmp = a->next;
if (a->action_type == action_type) {
// Pointless: run() will error out if open of device fails.
///* a->terminal of "" means "init's console" */
//if (a->terminal[0] && access(a->terminal, R_OK | W_OK)) {
// //message(L_LOG | L_CONSOLE, "Device %s cannot be opened in RW mode", a->terminal /*, strerror(errno)*/);
// delete_init_action(a);
//} else
if (a->action_type & (SYSINIT | WAIT | CTRLALTDEL | SHUTDOWN | RESTART)) {
waitfor(run(a));
delete_init_action(a);
} else if (a->action_type & ONCE) {
run(a);
delete_init_action(a);
} else if (a->action_type & (RESPAWN | ASKFIRST)) {
/* Only run stuff with pid==0. If they have
* a pid, that means it is still running */
if (a->pid == 0) {
a->pid = run(a);
}
}
}
}
}
static void init_reboot(unsigned long magic)
{
pid_t pid;
/* We have to fork here, since the kernel calls do_exit(0) in
* linux/kernel/sys.c, which can cause the machine to panic when
* the init process is killed.... */
pid = vfork();
if (pid == 0) { /* child */
reboot(magic);
_exit(0);
}
waitfor(pid);
}
static void kill_all_processes(void)
{
/* run everything to be run at "shutdown". This is done _prior_
* to killing everything, in case people wish to use scripts to
* shut things down gracefully... */
run_actions(SHUTDOWN);
/* first disable all our signals */
sigprocmask_allsigs(SIG_BLOCK);
message(L_CONSOLE | L_LOG, "The system is going down NOW!");
/* Allow Ctrl-Alt-Del to reboot system. */
init_reboot(RB_ENABLE_CAD);
/* Send signals to every process _except_ pid 1 */
message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "TERM");
kill(-1, SIGTERM);
sync();
sleep(1);
message(L_CONSOLE | L_LOG, "Sending SIG%s to all processes", "KILL");
kill(-1, SIGKILL);
sync();
sleep(1);
}
static void halt_reboot_pwoff(int sig)
{
const char *m;
int rb;
kill_all_processes();
m = "halt";
rb = RB_HALT_SYSTEM;
if (sig == SIGTERM) {
m = "reboot";
rb = RB_AUTOBOOT;
} else if (sig == SIGUSR2) {
m = "poweroff";
rb = RB_POWER_OFF;
}
message(L_CONSOLE | L_LOG, "Requesting system %s", m);
/* allow time for last message to reach serial console */
sleep(2);
init_reboot(rb);
loop_forever();
}
/* Handler for QUIT - exec "restart" action,
* else (no such action defined) do nothing */
static void exec_restart_action(int sig ATTRIBUTE_UNUSED)
{
struct init_action *a;
for (a = init_action_list; a; a = a->next) {
if (a->action_type & RESTART) {
kill_all_processes();
/* unblock all signals (blocked in kill_all_processes()) */
sigprocmask_allsigs(SIG_UNBLOCK);
/* Open the new terminal device */
open_stdio_to_tty(a->terminal, 0 /* - halt if open fails */);
messageD(L_CONSOLE | L_LOG, "Trying to re-exec %s", a->command);
init_exec(a->command);
sleep(2);
init_reboot(RB_HALT_SYSTEM);
loop_forever();
}
}
}
static void ctrlaltdel_signal(int sig ATTRIBUTE_UNUSED)
{
run_actions(CTRLALTDEL);
}
/* The SIGSTOP & SIGTSTP handler */
static void stop_handler(int sig ATTRIBUTE_UNUSED)
{
int saved_errno = errno;
got_cont = 0;
while (!got_cont)
pause();
errno = saved_errno;
}
/* The SIGCONT handler */
static void cont_handler(int sig ATTRIBUTE_UNUSED)
{
got_cont = 1;
}
static void new_init_action(uint8_t action_type, const char *command, const char *cons)
{
struct init_action *a, *last;
// Why?
// if (strcmp(cons, bb_dev_null) == 0 && (action & ASKFIRST))
// return;
/* Append to the end of the list */
for (a = last = init_action_list; a; a = a->next) {
/* don't enter action if it's already in the list,
* but do overwrite existing actions */
if ((strcmp(a->command, command) == 0)
&& (strcmp(a->terminal, cons) == 0)
) {
a->action_type = action_type;
return;
}
last = a;
}
a = xzalloc(sizeof(*a));
if (last) {
last->next = a;
} else {
init_action_list = a;
}
a->action_type = action_type;
safe_strncpy(a->command, command, sizeof(a->command));
safe_strncpy(a->terminal, cons, sizeof(a->terminal));
messageD(L_LOG | L_CONSOLE, "command='%s' action=%d tty='%s'\n",
a->command, a->action_type, a->terminal);
}
static void delete_init_action(struct init_action *action)
{
struct init_action *a, *b = NULL;
for (a = init_action_list; a; b = a, a = a->next) {
if (a == action) {
if (b == NULL) {
init_action_list = a->next;
} else {
b->next = a->next;
}
free(a);
break;
}
}
}
/* NOTE that if CONFIG_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 CONFIG_FEATURE_USE_INITTAB
* _is_ defined, but /etc/inittab is missing, this
* results in the same set of default behaviors.
*/
static void parse_inittab(void)
{
FILE *file;
char buf[COMMAND_SIZE];
if (ENABLE_FEATURE_USE_INITTAB)
file = fopen(INITTAB, "r");
else
file = NULL;
/* No inittab file -- set up some default behavior */
if (file == NULL) {
/* Reboot on Ctrl-Alt-Del */
new_init_action(CTRLALTDEL, "reboot", "");
/* Umount all filesystems on halt/reboot */
new_init_action(SHUTDOWN, "umount -a -r", "");
/* Swapoff on halt/reboot */
if (ENABLE_SWAPONOFF)
new_init_action(SHUTDOWN, "swapoff -a", "");
/* Prepare to restart init when a QUIT is received */
new_init_action(RESTART, "init", "");
/* Askfirst shell on tty1-4 */
new_init_action(ASKFIRST, bb_default_login_shell, "");
new_init_action(ASKFIRST, bb_default_login_shell, VC_2);
new_init_action(ASKFIRST, bb_default_login_shell, VC_3);
new_init_action(ASKFIRST, bb_default_login_shell, VC_4);
/* sysinit */
new_init_action(SYSINIT, INIT_SCRIPT, "");
return;
}
while (fgets(buf, COMMAND_SIZE, file) != NULL) {
static const char actions[] =
STR_SYSINIT "sysinit\0"
STR_RESPAWN "respawn\0"
STR_ASKFIRST "askfirst\0"
STR_WAIT "wait\0"
STR_ONCE "once\0"
STR_CTRLALTDEL "ctrlaltdel\0"
STR_SHUTDOWN "shutdown\0"
STR_RESTART "restart\0"
;
char tmpConsole[CONSOLE_NAME_SIZE];
char *id, *runlev, *action, *command;
const char *a;
/* Skip leading spaces */
id = skip_whitespace(buf);
/* Trim the trailing '\n' */
*strchrnul(id, '\n') = '\0';
/* Skip the line if it is a comment */
if (*id == '#' || *id == '\0')
continue;
/* Line is: "id:runlevel_ignored:action:command" */
runlev = strchr(id, ':');
if (runlev == NULL /*|| runlev[1] == '\0' - not needed */)
goto bad_entry;
action = strchr(runlev + 1, ':');
if (action == NULL /*|| action[1] == '\0' - not needed */)
goto bad_entry;
command = strchr(action + 1, ':');
if (command == NULL || command[1] == '\0')
goto bad_entry;
*command = '\0'; /* action => ":action\0" now */
for (a = actions; a[0]; a += strlen(a) + 1) {
if (strcmp(a + 1, action + 1) == 0) {
*runlev = '\0';
if (*id != '\0') {
if (strncmp(id, "/dev/", 5) == 0)
id += 5;
strcpy(tmpConsole, "/dev/");
safe_strncpy(tmpConsole + 5, id,
sizeof(tmpConsole) - 5);
id = tmpConsole;
}
new_init_action((uint8_t)a[0], command + 1, id);
goto next_line;
}
}
*command = ':';
/* Choke on an unknown action */
bad_entry:
message(L_LOG | L_CONSOLE, "Bad inittab entry: %s", id);
next_line: ;
}
fclose(file);
}
static void reload_signal(int sig ATTRIBUTE_UNUSED)
{
struct init_action *a, *tmp;
message(L_LOG, "reloading /etc/inittab");
/* disable old entrys */
for (a = init_action_list; a; a = a->next) {
a->action_type = ONCE;
}
parse_inittab();
if (ENABLE_FEATURE_KILL_REMOVED) {
/* Be nice and send SIGTERM first */
for (a = init_action_list; a; a = a->next) {
pid_t pid = a->pid;
if ((a->action_type & ONCE) && pid != 0) {
kill(pid, SIGTERM);
}
}
#if CONFIG_FEATURE_KILL_DELAY
/* NB: parent will wait in NOMMU case */
if ((BB_MMU ? fork() : vfork()) == 0) { /* child */
sleep(CONFIG_FEATURE_KILL_DELAY);
for (a = init_action_list; a; a = a->next) {
pid_t pid = a->pid;
if ((a->action_type & ONCE) && pid != 0) {
kill(pid, SIGKILL);
}
}
_exit(0);
}
#endif
}
/* remove unused entrys */
for (a = init_action_list; a; a = tmp) {
tmp = a->next;
if ((a->action_type & (ONCE | SYSINIT | WAIT)) && a->pid == 0) {
delete_init_action(a);
}
}
run_actions(RESPAWN);
}
int init_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int init_main(int argc, char **argv)
{
struct init_action *a;
pid_t wpid;
die_sleep = 30 * 24*60*60; /* if xmalloc will ever die... */
if (argc > 1 && !strcmp(argv[1], "-q")) {
return kill(1, SIGHUP);
}
if (!ENABLE_DEBUG_INIT) {
/* Expect to be invoked as init with PID=1 or be invoked as linuxrc */
if (getpid() != 1
&& (!ENABLE_FEATURE_INITRD || !strstr(applet_name, "linuxrc"))
) {
bb_show_usage();
}
/* Set up sig handlers -- be sure to
* clear all of these in run() */
signal(SIGQUIT, exec_restart_action);
bb_signals(0
+ (1 << SIGUSR1) /* halt */
+ (1 << SIGUSR2) /* poweroff */
+ (1 << SIGTERM) /* reboot */
, halt_reboot_pwoff);
signal(SIGINT, ctrlaltdel_signal);
signal(SIGCONT, cont_handler);
bb_signals(0
+ (1 << SIGSTOP)
+ (1 << SIGTSTP)
, stop_handler);
/* 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);
}
/* Figure out where the default console should be */
console_init();
set_sane_term();
chdir("/");
setsid();
{
const char *const *e;
/* Make sure environs is set to something sane */
for (e = environment; *e; e++)
putenv((char *) *e);
}
if (argc > 1) setenv("RUNLEVEL", argv[1], 1);
/* Hello world */
message(MAYBE_CONSOLE | L_LOG, "init started: %s", bb_banner);
/* Make sure there is enough memory to do something useful. */
if (ENABLE_SWAPONOFF) {
struct sysinfo info;
if (!sysinfo(&info) &&
(info.mem_unit ? : 1) * (long long)info.totalram < 1024*1024)
{
message(L_CONSOLE, "Low memory, forcing swapon");
/* swapon -a requires /proc typically */
new_init_action(SYSINIT, "mount -t proc proc /proc", "");
/* Try to turn on swap */
new_init_action(SYSINIT, "swapon -a", "");
run_actions(SYSINIT); /* wait and removing */
}
}
/* Check if we are supposed to be in single user mode */
if (argc > 1
&& (!strcmp(argv[1], "single") || !strcmp(argv[1], "-s") || LONE_CHAR(argv[1], '1'))
) {
/* Start a shell on console */
new_init_action(RESPAWN, bb_default_login_shell, "");
} else {
/* Not in single user mode -- see what inittab says */
/* NOTE that if CONFIG_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();
}
#if ENABLE_SELINUX
if (getenv("SELINUX_INIT") == NULL) {
int enforce = 0;
putenv((char*)"SELINUX_INIT=YES");
if (selinux_init_load_policy(&enforce) == 0) {
BB_EXECVP(argv[0], argv);
} else if (enforce > 0) {
/* SELinux in enforcing mode but load_policy failed */
message(L_CONSOLE, "Cannot load SELinux Policy. "
"Machine is in enforcing mode. Halting now.");
exit(1);
}
}
#endif /* CONFIG_SELINUX */
/* Make the command line just say "init" - thats all, nothing else */
strncpy(argv[0], "init", strlen(argv[0]));
/* Wipe argv[1]-argv[N] so they don't clutter the ps listing */
while (*++argv)
memset(*argv, 0, strlen(*argv));
/* Now run everything that needs to be run */
/* First run the sysinit command */
run_actions(SYSINIT);
/* Next run anything that wants to block */
run_actions(WAIT);
/* Next run anything to be run only once */
run_actions(ONCE);
/* Redefine SIGHUP to reread /etc/inittab */
if (ENABLE_FEATURE_USE_INITTAB)
signal(SIGHUP, reload_signal);
else
signal(SIGHUP, SIG_IGN);
/* Now run the looping stuff for the rest of forever */
while (1) {
/* run the respawn stuff */
run_actions(RESPAWN);
/* run the askfirst stuff */
run_actions(ASKFIRST);
/* Don't consume all CPU time -- sleep a bit */
sleep(1);
/* Wait for any child process to exit */
wpid = wait(NULL);
while (wpid > 0) {
/* Find out who died and clean up their corpse */
for (a = init_action_list; a; a = a->next) {
if (a->pid == wpid) {
/* Set the pid to 0 so that the process gets
* restarted by run_actions() */
a->pid = 0;
message(L_LOG, "process '%s' (pid %d) exited. "
"Scheduling for restart.",
a->command, wpid);
}
}
/* see if anyone else is waiting to be reaped */
wpid = wait_any_nohang(NULL);
}
}
}