finit/finit-mod.c

/*
Improved fast init

Copyright (c) 2008 Claudio Matsuoka

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <sys/reboot.h>
#include <sys/wait.h>
#include <linux/fs.h>


/* From sysvinit */
/* Set a signal handler. */
#define SETSIG(sa, sig, fun, flags) \
		do { \
			sa.sa_handler = fun; \
			sa.sa_flags = flags; \
			sigemptyset(&sa.sa_mask); \
			sigaction(sig, &sa, NULL); \
		} while(0)

#define touch(x) close(open((x), O_CREAT|O_WRONLY|O_TRUNC, 0644))


void shutdown(int);
void signal_handler(int);
void chld_handler(int);


int main()
{
	int i;
	FILE *f;
	char line[2096];
	int fd;
	DIR *dir;
	struct dirent *d;
	char filename[1024];
	struct sigaction sa, act;
	char hline[1024];
	char *x;
	sigset_t nmask, nmask2;

	chdir("/");
	umask(022);
	
	/*
	 * Signal management
	 */
	for (i = 1; i < NSIG; i++)
		SETSIG(sa, i, SIG_IGN, SA_RESTART);

	SETSIG(sa, SIGINT,  shutdown,       0);
	SETSIG(sa, SIGPWR,  signal_handler, 0);
	SETSIG(sa, SIGUSR1, shutdown,       0);
	SETSIG(sa, SIGUSR2, shutdown,       0);
	SETSIG(sa, SIGTERM, signal_handler, 0);
	SETSIG(sa, SIGKILL, signal_handler, 0);
	SETSIG(sa, SIGALRM, signal_handler, 0);
	SETSIG(sa, SIGHUP,  signal_handler, 0);
	SETSIG(sa, SIGSTOP, signal_handler, SA_RESTART);
	SETSIG(sa, SIGCONT, signal_handler, SA_RESTART);
	SETSIG(sa, SIGCHLD, chld_handler,   SA_RESTART);
	
	/* Block sigchild while forking */
	sigemptyset(&nmask);
	sigaddset(&nmask, SIGCHLD);
	sigprocmask(SIG_BLOCK, &nmask, NULL);

	reboot(RB_DISABLE_CAD);

	/*
	 * Parse kernel parameters
	 */
	if ((f = fopen("/proc/cmdline", "r")) != NULL) {
		fgets(line, 2095, f);
		if (strstr(line, "quiet")) {
			close(0);
			close(1);
			close(2);
		}
		fclose(f);
	}

	setsid();

	/*
	 * Mount filesystems
	 */
	mount("proc", "/proc", "proc", 0, NULL);
	mount("sysfs", "/sys", "sysfs", 0, NULL);
	mount("devpts", "/dev/pts", "devpts", 0, "gid=5,mode=620");
	mount("tmpfs", "/dev/shm", "tmpfs", 0, NULL);
	mount("tmpfs", "/tmp", "tmpfs", 0, "mode=1777,size=128m");
	mount("/mnt", "/", NULL, MS_MOVE, NULL);

	/*
	 * Time adjustments
	 */
	if ((fd = open("/etc/adjtime", O_CREAT|O_WRONLY|O_TRUNC, 0644)) >= 0) {
		write(fd, "0.0 0 0.0\n", 10);
		close(fd);
	}
	system("/sbin/hwclock --hctosys --localtime");

	/*
	 * Network stuff
	 */
	system("mkdir -p /dev/shm/network");
	system("mkdir -p /dev/shm/resolvconf/interface");

	if ((dir = opendir("/etc/resolvconf/run/interface")) != NULL) {
		while ((d = readdir(dir)) != NULL) {
			if (isalnum(d->d_name[0]))
				continue;
			sprintf(filename, "/etc/resolvconf/run/interface/%s",
								d->d_name);
			unlink(filename);
		}

		closedir(dir);
	}

	touch("/var/run/utmp");
	touch("/etc/resolvconf/run/enable-updates");

	chdir("/etc/resolvconf/run/interface");
	system("/bin/run-parts --arg=-i /etc/resolvconf/update.d");
	chdir("/");
	
	touch("/etc/network/run/ifstate");

	if ((f = fopen("/etc/hostname", "r")) != NULL) {
		fgets(hline, 1023, f);	
		if ((x = strchr(hline, 0x0a)) != NULL)
			*x = 0;

		sethostname(hline, strlen(hline)); 
		fclose(f);
		
	}

	system("/sbin/ifconfig lo 127.0.0.1 netmask 255.0.0.0 up > /dev/null");

	/*
	 * Set random seed
	 */
	/* Bug: the eeepc never sets its random seed from file */
	system("/bin/cat /var/lib/urandom/random-seed >/dev/urandom "
						"> /dev/null 2>&1");
	unlink("/var/lib/urandom/random-seed");

	umask(077);
	system("/bin/dd if=/dev/urandom of=/var/lib/urandom/random-seed "
					"bs=4096 count=1 >/dev/null 2>&1");

	/*
	 * Misc setup
	 */
	system("/bin/rm -rf /tmp/* /tmp/.* 2>/dev/null");
	unlink("/var/run/.clean");
	unlink("/var/lock/.clean");
	umask(0);
	mkdir("/tmp/.X11-unix", 01777);
	mkdir("/tmp/.ICE-unix", 01777);
	umask(022);

	if (!fork()) {
		/* child process */

		vhangup();

		close(2);
		close(1);
		close(0);

		if (open("/dev/tty1", O_RDWR, 0))
			exit(1);

		sigemptyset(&act.sa_mask);
		act.sa_handler = SIG_DFL;

		sigemptyset(&nmask2);
		sigaddset(&nmask2, SIGCHLD);
		sigprocmask(SIG_UNBLOCK, &nmask2, NULL);

		/* Bug: no signal 0 */
		for (i = 0; i < NSIG; i++)
			sigaction(i, &sa, NULL);

		dup2(0, 0);
		dup2(0, 1);
		dup2(0, 2);

		touch("/tmp/nologin");
		
		while (access("/tmp/shutdown", F_OK) < 0)
			system("su -c startx -l user &> /dev/null");

		exit(0);
	}
	
	/* parent process */

	system("/sbin/getty 38400 tty3 &");
	sleep(1);
	system("/usr/sbin/services.sh &> /dev/null &");

	while (1) {
		sigemptyset(&nmask);
		pselect(0, NULL, NULL, NULL, NULL, &nmask);
	}
}


/*
 * Shut down on INT USR1 USR2
 */
void shutdown(int sig)
{
	int fd;

	system("/usr/bin/touch /tmp/shutdown");

	kill(-1, SIGTERM);

	system("/bin/echo -e \"\033[?25l\033[30;40m\"; "
				"/bin/cp /boot/shutdown.fb /dev/fb/0");
	sleep(1);
	sleep(1);

	system("/usr/sbin/alsactl store > /dev/null 2>&1");
	system("/sbin/hwclock --systohc --localtime");
	system("/sbin/unionctl.static / --remove / > /dev/null 2>&1");

	kill(-1, SIGKILL);

	sync();
	sync();
	system("/bin/mount -n -o remount,ro /");

	system("/sbin/unionctl.static / --remove / > /dev/null 2>&1");

	if (sig == SIGINT || sig == SIGUSR1)
		reboot(RB_AUTOBOOT);

	if ((fd = open("/proc/acpi/sleep", O_WRONLY)) >= 0) {
		write(fd, "5", 1);
		close(fd);
	}
}


/*
 * SIGCHLD: one of our children has died
 */
void chld_handler(int sig)
{
	int status;

	while (waitpid(-1, &status, WNOHANG) != 0) {
		if (errno == ECHILD)
			break;
	}
}


/*
 * We got a signal (PWR TERM ALRM HUP STOP CONT)
 */
void signal_handler(int sig)
{
	/* do nothing */
}