Imported from util-linux-2.11x tarball.

[thirdparty/util-linux.git] / disk-utils / mkfs.minix.c

/*
 * mkfs.c - make a linux (minix) file-system.
 *
 * (C) 1991 Linus Torvalds. This file may be redistributed as per
 * the Linux copyright.
 */

/*
 * DD.MM.YY
 *
 * 24.11.91  -	Time began. Used the fsck sources to get started.
 *
 * 25.11.91  -	Corrected some bugs. Added support for ".badblocks"
 *		The algorithm for ".badblocks" is a bit weird, but
 *		it should work. Oh, well.
 *
 * 25.01.92  -	Added the -l option for getting the list of bad blocks
 *		out of a named file. (Dave Rivers, rivers@ponds.uucp)
 *
 * 28.02.92  -	Added %-information when using -c.
 *
 * 28.02.93  -	Added support for other namelengths than the original
 *		14 characters so that I can test the new kernel routines..
 *
 * 09.10.93  -	Make exit status conform to that required by fsutil
 *		(Rik Faith, faith@cs.unc.edu)
 *
 * 31.10.93  -	Added inode request feature, for backup floppies: use
 *		32 inodes, for a news partition use more.
 *		(Scott Heavner, sdh@po.cwru.edu)
 *
 * 03.01.94  -	Added support for file system valid flag.
 *		(Dr. Wettstein, greg%wind.uucp@plains.nodak.edu)
 *
 * 30.10.94  -  Added support for v2 filesystem
 *		(Andreas Schwab, schwab@issan.informatik.uni-dortmund.de)
 * 
 * 09.11.94  -	Added test to prevent overwrite of mounted fs adapted
 *		from Theodore Ts'o's (tytso@athena.mit.edu) mke2fs
 *		program.  (Daniel Quinlan, quinlan@yggdrasil.com)
 *
 * 03.20.95  -	Clear first 512 bytes of filesystem to make certain that
 *		the filesystem is not misidentified as a MS-DOS FAT filesystem.
 *		(Daniel Quinlan, quinlan@yggdrasil.com)
 *
 * 02.07.96  -  Added small patch from Russell King to make the program a
 *		good deal more portable (janl@math.uio.no)
 *
 * Usage:  mkfs [-c | -l filename ] [-v] [-nXX] [-iXX] device [size-in-blocks]
 *
 *	-c for readablility checking (SLOW!)
 *      -l for getting a list of bad blocks from a file.
 *	-n for namelength (currently the kernel only uses 14 or 30)
 *	-i for number of inodes
 *	-v for v2 filesystem
 *
 * The device may be a block device or a image of one, but this isn't
 * enforced (but it's not much fun on a character device :-). 
 */

#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <stdlib.h>
#include <termios.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <mntent.h>
#include <getopt.h>

#include "minix.h"
#include "nls.h"

#ifndef BLKGETSIZE
#define BLKGETSIZE _IO(0x12,96)    /* return device size */
#endif

#ifdef MINIX2_SUPER_MAGIC2
#define HAVE_MINIX2 1
#endif

#ifndef __GNUC__
#error "needs gcc for the bitop-__asm__'s"
#endif

#define MINIX_ROOT_INO 1
#define MINIX_BAD_INO 2

#define TEST_BUFFER_BLOCKS 16
#define MAX_GOOD_BLOCKS 512

#define UPPER(size,n) ((size+((n)-1))/(n))
#define INODE_SIZE (sizeof(struct minix_inode))
#ifdef HAVE_MINIX2
#define INODE_SIZE2 (sizeof(struct minix2_inode))
#define INODE_BLOCKS UPPER(INODES, (version2 ? MINIX2_INODES_PER_BLOCK \
				    : MINIX_INODES_PER_BLOCK))
#else
#define INODE_BLOCKS UPPER(INODES, (MINIX_INODES_PER_BLOCK))
#endif
#define INODE_BUFFER_SIZE (INODE_BLOCKS * BLOCK_SIZE)

#define BITS_PER_BLOCK (BLOCK_SIZE<<3)

static char * program_name = "mkfs";
static char * device_name = NULL;
static int DEV = -1;
static long BLOCKS = 0;
static int check = 0;
static int badblocks = 0;
static int namelen = 30;	/* default (changed to 30, per Linus's
				   suggestion, Sun Nov 21 08:05:07 1993) */
static int dirsize = 32;
static int magic = MINIX_SUPER_MAGIC2;
static int version2 = 0;

static char root_block[BLOCK_SIZE] = "\0";

static char * inode_buffer = NULL;
#define Inode (((struct minix_inode *) inode_buffer)-1)
#ifdef HAVE_MINIX2
#define Inode2 (((struct minix2_inode *) inode_buffer)-1)
#endif
static char super_block_buffer[BLOCK_SIZE];
static char boot_block_buffer[512];
#define Super (*(struct minix_super_block *)super_block_buffer)
#define INODES ((unsigned long)Super.s_ninodes)
#ifdef HAVE_MINIX2
#define ZONES ((unsigned long)(version2 ? Super.s_zones : Super.s_nzones))
#else
#define ZONES ((unsigned long)(Super.s_nzones))
#endif
#define IMAPS ((unsigned long)Super.s_imap_blocks)
#define ZMAPS ((unsigned long)Super.s_zmap_blocks)
#define FIRSTZONE ((unsigned long)Super.s_firstdatazone)
#define ZONESIZE ((unsigned long)Super.s_log_zone_size)
#define MAXSIZE ((unsigned long)Super.s_max_size)
#define MAGIC (Super.s_magic)
#define NORM_FIRSTZONE (2+IMAPS+ZMAPS+INODE_BLOCKS)

static char *inode_map;
static char *zone_map;

static unsigned short good_blocks_table[MAX_GOOD_BLOCKS];
static int used_good_blocks = 0;
static unsigned long req_nr_inodes = 0;

#include "bitops.h"

#define inode_in_use(x) (bit(inode_map,(x)))
#define zone_in_use(x) (bit(zone_map,(x)-FIRSTZONE+1))

#define mark_inode(x) (setbit(inode_map,(x)))
#define unmark_inode(x) (clrbit(inode_map,(x)))

#define mark_zone(x) (setbit(zone_map,(x)-FIRSTZONE+1))
#define unmark_zone(x) (clrbit(zone_map,(x)-FIRSTZONE+1))

static void
die(char *str) {
	fprintf(stderr, "%s: ", program_name);
	fprintf(stderr, str, device_name);
	fprintf(stderr, "\n");
	exit(8);
}

static void
usage(void) {
	fprintf(stderr, "%s (%s)\n", program_name, util_linux_version);
	fprintf(stderr,
		_("Usage: %s [-c | -l filename] [-nXX] [-iXX] /dev/name [blocks]\n"),
		  program_name);
	exit(16);
}

/*
 * Check to make certain that our new filesystem won't be created on
 * an already mounted partition.  Code adapted from mke2fs, Copyright
 * (C) 1994 Theodore Ts'o.  Also licensed under GPL.
 */
static void
check_mount(void) {
	FILE * f;
	struct mntent * mnt;

	if ((f = setmntent (MOUNTED, "r")) == NULL)
		return;
	while ((mnt = getmntent (f)) != NULL)
		if (strcmp (device_name, mnt->mnt_fsname) == 0)
			break;
	endmntent (f);
	if (!mnt)
		return;

	die(_("%s is mounted; will not make a filesystem here!"));
}

static long
valid_offset (int fd, int offset) {
	char ch;

	if (lseek (fd, offset, 0) < 0)
		return 0;
	if (read (fd, &ch, 1) < 1)
		return 0;
	return 1;
}

static int
count_blocks (int fd) {
	int high, low;

	low = 0;
	for (high = 1; valid_offset (fd, high); high *= 2)
		low = high;
	while (low < high - 1)
	{
		const int mid = (low + high) / 2;

		if (valid_offset (fd, mid))
			low = mid;
		else
			high = mid;
	}
	valid_offset (fd, 0);
	return (low + 1);
}

static int
get_size(const char  *file) {
	int	fd;
	long	size;

	fd = open(file, O_RDWR);
	if (fd < 0) {
		perror(file);
		exit(1);
	}
	if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
		close(fd);
		return (size * 512);
	}
		
	size = count_blocks(fd);
	close(fd);
	return size;
}

static void
write_tables(void) {
	/* Mark the super block valid. */
	Super.s_state |= MINIX_VALID_FS;
	Super.s_state &= ~MINIX_ERROR_FS;

	if (lseek(DEV, 0, SEEK_SET))
		die(_("seek to boot block failed in write_tables"));
	if (512 != write(DEV, boot_block_buffer, 512))
		die(_("unable to clear boot sector"));
	if (BLOCK_SIZE != lseek(DEV, BLOCK_SIZE, SEEK_SET))
		die(_("seek failed in write_tables"));
	if (BLOCK_SIZE != write(DEV, super_block_buffer, BLOCK_SIZE))
		die(_("unable to write super-block"));
	if (IMAPS*BLOCK_SIZE != write(DEV,inode_map,IMAPS*BLOCK_SIZE))
		die(_("unable to write inode map"));
	if (ZMAPS*BLOCK_SIZE != write(DEV,zone_map,ZMAPS*BLOCK_SIZE))
		die(_("unable to write zone map"));
	if (INODE_BUFFER_SIZE != write(DEV,inode_buffer,INODE_BUFFER_SIZE))
		die(_("unable to write inodes"));
	
}

static void
write_block(int blk, char * buffer) {
	if (blk*BLOCK_SIZE != lseek(DEV, blk*BLOCK_SIZE, SEEK_SET))
		die(_("seek failed in write_block"));
	if (BLOCK_SIZE != write(DEV, buffer, BLOCK_SIZE))
		die(_("write failed in write_block"));
}

static int
get_free_block(void) {
	int blk;

	if (used_good_blocks+1 >= MAX_GOOD_BLOCKS)
		die(_("too many bad blocks"));
	if (used_good_blocks)
		blk = good_blocks_table[used_good_blocks-1]+1;
	else
		blk = FIRSTZONE;
	while (blk < ZONES && zone_in_use(blk))
		blk++;
	if (blk >= ZONES)
		die(_("not enough good blocks"));
	good_blocks_table[used_good_blocks] = blk;
	used_good_blocks++;
	return blk;
}

static void
mark_good_blocks(void) {
	int blk;

	for (blk=0 ; blk < used_good_blocks ; blk++)
		mark_zone(good_blocks_table[blk]);
}

static inline int
next(int zone) {
	if (!zone)
		zone = FIRSTZONE-1;
	while (++zone < ZONES)
		if (zone_in_use(zone))
			return zone;
	return 0;
}

static void
make_bad_inode(void) {
	struct minix_inode * inode = &Inode[MINIX_BAD_INO];
	int i,j,zone;
	int ind=0,dind=0;
	unsigned short ind_block[BLOCK_SIZE>>1];
	unsigned short dind_block[BLOCK_SIZE>>1];

#define NEXT_BAD (zone = next(zone))

	if (!badblocks)
		return;
	mark_inode(MINIX_BAD_INO);
	inode->i_nlinks = 1;
	inode->i_time = time(NULL);
	inode->i_mode = S_IFREG + 0000;
	inode->i_size = badblocks*BLOCK_SIZE;
	zone = next(0);
	for (i=0 ; i<7 ; i++) {
		inode->i_zone[i] = zone;
		if (!NEXT_BAD)
			goto end_bad;
	}
	inode->i_zone[7] = ind = get_free_block();
	memset(ind_block,0,BLOCK_SIZE);
	for (i=0 ; i<512 ; i++) {
		ind_block[i] = zone;
		if (!NEXT_BAD)
			goto end_bad;
	}
	inode->i_zone[8] = dind = get_free_block();
	memset(dind_block,0,BLOCK_SIZE);
	for (i=0 ; i<512 ; i++) {
		write_block(ind,(char *) ind_block);
		dind_block[i] = ind = get_free_block();
		memset(ind_block,0,BLOCK_SIZE);
		for (j=0 ; j<512 ; j++) {
			ind_block[j] = zone;
			if (!NEXT_BAD)
				goto end_bad;
		}
	}
	die(_("too many bad blocks"));
end_bad:
	if (ind)
		write_block(ind, (char *) ind_block);
	if (dind)
		write_block(dind, (char *) dind_block);
}

#ifdef HAVE_MINIX2
static void
make_bad_inode2 (void) {
	struct minix2_inode *inode = &Inode2[MINIX_BAD_INO];
	int i, j, zone;
	int ind = 0, dind = 0;
	unsigned long ind_block[BLOCK_SIZE >> 2];
	unsigned long dind_block[BLOCK_SIZE >> 2];

	if (!badblocks)
		return;
	mark_inode (MINIX_BAD_INO);
	inode->i_nlinks = 1;
	inode->i_atime = inode->i_mtime = inode->i_ctime = time (NULL);
	inode->i_mode = S_IFREG + 0000;
	inode->i_size = badblocks * BLOCK_SIZE;
	zone = next (0);
	for (i = 0; i < 7; i++) {
		inode->i_zone[i] = zone;
		if (!NEXT_BAD)
			goto end_bad;
	}
	inode->i_zone[7] = ind = get_free_block ();
	memset (ind_block, 0, BLOCK_SIZE);
	for (i = 0; i < 256; i++) {
		ind_block[i] = zone;
		if (!NEXT_BAD)
			goto end_bad;
	}
	inode->i_zone[8] = dind = get_free_block ();
	memset (dind_block, 0, BLOCK_SIZE);
	for (i = 0; i < 256; i++) {
		write_block (ind, (char *) ind_block);
		dind_block[i] = ind = get_free_block ();
		memset (ind_block, 0, BLOCK_SIZE);
		for (j = 0; j < 256; j++) {
			ind_block[j] = zone;
			if (!NEXT_BAD)
				goto end_bad;
		}
	}
	/* Could make triple indirect block here */
	die (_("too many bad blocks"));
 end_bad:
	if (ind)
		write_block (ind, (char *) ind_block);
	if (dind)
		write_block (dind, (char *) dind_block);
}
#endif

static void
make_root_inode(void) {
	struct minix_inode * inode = &Inode[MINIX_ROOT_INO];

	mark_inode(MINIX_ROOT_INO);
	inode->i_zone[0] = get_free_block();
	inode->i_nlinks = 2;
	inode->i_time = time(NULL);
	if (badblocks)
		inode->i_size = 3*dirsize;
	else {
		root_block[2*dirsize] = '\0';
		root_block[2*dirsize+1] = '\0';
		inode->i_size = 2*dirsize;
	}
	inode->i_mode = S_IFDIR + 0755;
	inode->i_uid = getuid();
	if (inode->i_uid)
		inode->i_gid = getgid();
	write_block(inode->i_zone[0],root_block);
}

#ifdef HAVE_MINIX2
static void
make_root_inode2 (void) {
	struct minix2_inode *inode = &Inode2[MINIX_ROOT_INO];

	mark_inode (MINIX_ROOT_INO);
	inode->i_zone[0] = get_free_block ();
	inode->i_nlinks = 2;
	inode->i_atime = inode->i_mtime = inode->i_ctime = time (NULL);
	if (badblocks)
		inode->i_size = 3 * dirsize;
	else {
		root_block[2 * dirsize] = '\0';
		root_block[2 * dirsize + 1] = '\0';
		inode->i_size = 2 * dirsize;
	}
	inode->i_mode = S_IFDIR + 0755;
	inode->i_uid = getuid();
	if (inode->i_uid)
		inode->i_gid = getgid();
	write_block (inode->i_zone[0], root_block);
}
#endif

static void
setup_tables(void) {
	int i;
	unsigned long inodes;

	memset(super_block_buffer,0,BLOCK_SIZE);
	memset(boot_block_buffer,0,512);
	MAGIC = magic;
	ZONESIZE = 0;
	MAXSIZE = version2 ? 0x7fffffff : (7+512+512*512)*1024;
	ZONES = BLOCKS;

/* some magic nrs: 1 inode / 3 blocks */
	if ( req_nr_inodes == 0 ) 
		inodes = BLOCKS/3;
	else
		inodes = req_nr_inodes;
	/* Round up inode count to fill block size */
#ifdef HAVE_MINIX2
	if (version2)
		inodes = ((inodes + MINIX2_INODES_PER_BLOCK - 1) &
			  ~(MINIX2_INODES_PER_BLOCK - 1));
	else
#endif
		inodes = ((inodes + MINIX_INODES_PER_BLOCK - 1) &
			  ~(MINIX_INODES_PER_BLOCK - 1));
	if (inodes > 65535)
		inodes = 65535;
	INODES = inodes;
	IMAPS = UPPER(INODES + 1,BITS_PER_BLOCK);
	ZMAPS = UPPER(BLOCKS - (1+IMAPS+INODE_BLOCKS), BITS_PER_BLOCK+1);
	/* The old code here
	 * ZMAPS = 0;
	 * while (ZMAPS != UPPER(BLOCKS - NORM_FIRSTZONE + 1,BITS_PER_BLOCK))
	 *	  ZMAPS = UPPER(BLOCKS - NORM_FIRSTZONE + 1,BITS_PER_BLOCK);
	 * was no good, since it may loop. - aeb
	 */
	FIRSTZONE = NORM_FIRSTZONE;
	inode_map = malloc(IMAPS * BLOCK_SIZE);
	zone_map = malloc(ZMAPS * BLOCK_SIZE);
	if (!inode_map || !zone_map)
		die(_("unable to allocate buffers for maps"));
	memset(inode_map,0xff,IMAPS * BLOCK_SIZE);
	memset(zone_map,0xff,ZMAPS * BLOCK_SIZE);
	for (i = FIRSTZONE ; i<ZONES ; i++)
		unmark_zone(i);
	for (i = MINIX_ROOT_INO ; i<=INODES ; i++)
		unmark_inode(i);
	inode_buffer = malloc(INODE_BUFFER_SIZE);
	if (!inode_buffer)
		die(_("unable to allocate buffer for inodes"));
	memset(inode_buffer,0,INODE_BUFFER_SIZE);
	printf(_("%ld inodes\n"),INODES);
	printf(_("%ld blocks\n"),ZONES);
	printf(_("Firstdatazone=%ld (%ld)\n"),FIRSTZONE,NORM_FIRSTZONE);
	printf(_("Zonesize=%d\n"),BLOCK_SIZE<<ZONESIZE);
	printf(_("Maxsize=%ld\n\n"),MAXSIZE);
}

/*
 * Perform a test of a block; return the number of
 * blocks readable/writeable.
 */
static long
do_check(char * buffer, int try, unsigned int current_block) {
	long got;
	
	/* Seek to the correct loc. */
	if (lseek(DEV, current_block * BLOCK_SIZE, SEEK_SET) !=
		       current_block * BLOCK_SIZE ) {
		 die(_("seek failed during testing of blocks"));
	}


	/* Try the read */
	got = read(DEV, buffer, try * BLOCK_SIZE);
	if (got < 0) got = 0;	
	if (got & (BLOCK_SIZE - 1 )) {
		printf(_("Weird values in do_check: probably bugs\n"));
	}
	got /= BLOCK_SIZE;
	return got;
}

static unsigned int currently_testing = 0;

static void
alarm_intr(int alnum) {
	if (currently_testing >= ZONES)
		return;
	signal(SIGALRM,alarm_intr);
	alarm(5);
	if (!currently_testing)
		return;
	printf("%d ...", currently_testing);
	fflush(stdout);
}

static void
check_blocks(void) {
	int try,got;
	static char buffer[BLOCK_SIZE * TEST_BUFFER_BLOCKS];

	currently_testing=0;
	signal(SIGALRM,alarm_intr);
	alarm(5);
	while (currently_testing < ZONES) {
		if (lseek(DEV,currently_testing*BLOCK_SIZE,SEEK_SET) !=
		currently_testing*BLOCK_SIZE)
			die(_("seek failed in check_blocks"));
		try = TEST_BUFFER_BLOCKS;
		if (currently_testing + try > ZONES)
			try = ZONES-currently_testing;
		got = do_check(buffer, try, currently_testing);
		currently_testing += got;
		if (got == try)
			continue;
		if (currently_testing < FIRSTZONE)
			die(_("bad blocks before data-area: cannot make fs"));
		mark_zone(currently_testing);
		badblocks++;
		currently_testing++;
	}
	if (badblocks > 1)
		printf(_("%d bad blocks\n"), badblocks);
	else if (badblocks == 1)
		printf(_("one bad block\n"));
}

static void
get_list_blocks(char *filename) {
	FILE *listfile;
	unsigned long blockno;

	listfile = fopen(filename,"r");
	if (listfile == NULL)
		die(_("can't open file of bad blocks"));

	while (!feof(listfile)) {
		fscanf(listfile,"%ld\n", &blockno);
		mark_zone(blockno);
		badblocks++;
	}
	fclose(listfile);

	if(badblocks > 1)
		printf(_("%d bad blocks\n"), badblocks);
	else if (badblocks == 1)
		printf(_("one bad block\n"));
}

int
main(int argc, char ** argv) {
  int i;
  char * tmp;
  struct stat statbuf;
  char * listfile = NULL;
  char * p;

  if (argc && *argv)
    program_name = *argv;
  if ((p = strrchr(program_name, '/')) != NULL)
    program_name = p+1;

  setlocale(LC_ALL, "");
  bindtextdomain(PACKAGE, LOCALEDIR);
  textdomain(PACKAGE);

  if (argc == 2 &&
      (!strcmp(argv[1], "-V") || !strcmp(argv[1], "--version"))) {
	  printf(_("%s from %s\n"), program_name, util_linux_version);
	  exit(0);
  }

  if (INODE_SIZE * MINIX_INODES_PER_BLOCK != BLOCK_SIZE)
    die(_("bad inode size"));
#ifdef HAVE_MINIX2
  if (INODE_SIZE2 * MINIX2_INODES_PER_BLOCK != BLOCK_SIZE)
    die(_("bad inode size"));
#endif
  opterr = 0;
  while ((i = getopt(argc, argv, "ci:l:n:v")) != -1)
    switch (i) {
      case 'c':
	check=1; break;
      case 'i':
	req_nr_inodes = (unsigned long) atol(optarg);
	break;
      case 'l':
	listfile = optarg; break;
      case 'n':
	i = strtoul(optarg,&tmp,0);
	if (*tmp)
	  usage();
	if (i == 14)
	  magic = MINIX_SUPER_MAGIC;
	else if (i == 30)
	  magic = MINIX_SUPER_MAGIC2;
	else
	  usage();
	namelen = i;
	dirsize = i+2;
	break;
      case 'v':
#ifndef HAVE_MINIX2
	fprintf(stderr,
		_("%s: not compiled with minix v2 support\n"),
		program_name);
	exit(-1);
#endif
	version2 = 1;
	break;
      default:
	usage();
    }
  argc -= optind;
  argv += optind;
  if (argc > 0 && !device_name) {
    device_name = argv[0];
    argc--;
    argv++;
  }
  if (argc > 0) {
     BLOCKS = strtol(argv[0],&tmp,0);
     if (*tmp) {
       printf(_("strtol error: number of blocks not specified"));
       usage();
     }
  }

  if (device_name && !BLOCKS)
    BLOCKS = get_size (device_name) / 1024;
  if (!device_name || BLOCKS<10) {
    usage();
  }
#ifdef HAVE_MINIX2
  if (version2) {
    if (namelen == 14)
      magic = MINIX2_SUPER_MAGIC;
    else
      magic = MINIX2_SUPER_MAGIC2;
  } else
#endif
    if (BLOCKS > 65535)
      BLOCKS = 65535;
  check_mount();		/* is it already mounted? */
  tmp = root_block;
  *(short *)tmp = 1;
  strcpy(tmp+2,".");
  tmp += dirsize;
  *(short *)tmp = 1;
  strcpy(tmp+2,"..");
  tmp += dirsize;
  *(short *)tmp = 2;
  strcpy(tmp+2,".badblocks");
  DEV = open(device_name,O_RDWR );
  if (DEV<0)
    die(_("unable to open %s"));
  if (fstat(DEV,&statbuf)<0)
    die(_("unable to stat %s"));
  if (!S_ISBLK(statbuf.st_mode))
    check=0;
  else if (statbuf.st_rdev == 0x0300 || statbuf.st_rdev == 0x0340)
    die(_("will not try to make filesystem on '%s'"));
  setup_tables();
  if (check)
    check_blocks();
  else if (listfile)
    get_list_blocks(listfile);
#ifdef HAVE_MINIX2
  if (version2) {
    make_root_inode2 ();
    make_bad_inode2 ();
  } else
#endif
    {
      make_root_inode();
      make_bad_inode();
    }
  mark_good_blocks();
  write_tables();
  return 0;
}