/* vi: set sw=4 ts=4: */
/*
 * fsck.c - a file system consistency checker for Linux.
 *
 * (C) 1991, 1992 Linus Torvalds. This file may be redistributed
 * as per the GNU copyleft.
 */

/*
 * 09.11.91  -  made the first rudimetary functions
 *
 * 10.11.91  -  updated, does checking, no repairs yet.
 *		Sent out to the mailing-list for testing.
 *
 * 14.11.91  -	Testing seems to have gone well. Added some
 *		correction-code, and changed some functions.
 *
 * 15.11.91  -  More correction code. Hopefully it notices most
 *		cases now, and tries to do something about them.
 *
 * 16.11.91  -  More corrections (thanks to Mika Jalava). Most
 *		things seem to work now. Yeah, sure.
 *
 *
 * 19.04.92  -	Had to start over again from this old version, as a
 *		kernel bug ate my enhanced fsck in february.
 *
 * 28.02.93  -	added support for different directory entry sizes..
 *
 * Sat Mar  6 18:59:42 1993, faith@cs.unc.edu: Output namelen with
 *                           super-block information
 *
 * Sat Oct  9 11:17:11 1993, faith@cs.unc.edu: make exit status conform
 *                           to that required by fsutil
 *
 * Mon Jan  3 11:06:52 1994 - Dr. Wettstein (greg%wind.uucp@plains.nodak.edu)
 *			      Added support for file system valid flag.  Also
 *			      added program_version variable and output of
 *			      program name and version number when program
 *			      is executed.
 *
 * 30.10.94 - added support for v2 filesystem
 *            (Andreas Schwab, schwab@issan.informatik.uni-dortmund.de)
 *
 * 10.12.94  -  added test to prevent checking of mounted fs adapted
 *              from Theodore Ts'o's (tytso@athena.mit.edu) e2fsck
 *              program.  (Daniel Quinlan, quinlan@yggdrasil.com)
 *
 * 01.07.96  - Fixed the v2 fs stuff to use the right #defines and such
 *	       for modern libcs (janl@math.uio.no, Nicolai Langfeldt)
 *
 * 02.07.96  - Added C bit fiddling routines from rmk@ecs.soton.ac.uk 
 *             (Russell King).  He made them for ARM.  It would seem
 *	       that the ARM is powerful enough to do this in C whereas
 *             i386 and m64k must use assembly to get it fast >:-)
 *	       This should make minix fsck systemindependent.
 *	       (janl@math.uio.no, Nicolai Langfeldt)
 *
 * 04.11.96  - Added minor fixes from Andreas Schwab to avoid compiler
 *             warnings.  Added mc68k bitops from 
 *	       Joerg Dorchain <dorchain@mpi-sb.mpg.de>.
 *
 * 06.11.96  - Added v2 code submitted by Joerg Dorchain, but written by
 *             Andreas Schwab.
 *
 * 1999-02-22 Arkadiusz Mikiewicz <misiek@misiek.eu.org>
 * - added Native Language Support
 *
 *
 * I've had no time to add comments - hopefully the function names
 * are comments enough. As with all file system checkers, this assumes
 * the file system is quiescent - don't use it on a mounted device
 * unless you can be sure nobody is writing to it (and remember that the
 * kernel can write to it when it searches for files).
 *
 * Usuage: fsck [-larvsm] device
 *	-l for a listing of all the filenames
 *	-a for automatic repairs (not implemented)
 *	-r for repairs (interactive) (not implemented)
 *	-v for verbose (tells how many files)
 *	-s for super-block info
 *	-m for minix-like "mode not cleared" warnings
 *	-f force filesystem check even if filesystem marked as valid
 *
 * 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 "internal.h"
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <ctype.h>
#include <stdlib.h>
#include <termios.h>
#include <mntent.h>
#include <sys/stat.h>
#include <sys/param.h>

 
 typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;


#define MINIX_ROOT_INO 1
#define MINIX_LINK_MAX	250
#define MINIX2_LINK_MAX	65530

#define MINIX_I_MAP_SLOTS	8
#define MINIX_Z_MAP_SLOTS	64
#define MINIX_SUPER_MAGIC	0x137F		/* original minix fs */
#define MINIX_SUPER_MAGIC2	0x138F		/* minix fs, 30 char names */
#define MINIX2_SUPER_MAGIC	0x2468		/* minix V2 fs */
#define MINIX2_SUPER_MAGIC2	0x2478		/* minix V2 fs, 30 char names */
#define MINIX_VALID_FS		0x0001		/* Clean fs. */
#define MINIX_ERROR_FS		0x0002		/* fs has errors. */

#define MINIX_INODES_PER_BLOCK ((BLOCK_SIZE)/(sizeof (struct minix_inode)))
#define MINIX2_INODES_PER_BLOCK ((BLOCK_SIZE)/(sizeof (struct minix2_inode)))

#define MINIX_V1		0x0001		/* original minix fs */
#define MINIX_V2		0x0002		/* minix V2 fs */

#define INODE_VERSION(inode)	inode->i_sb->u.minix_sb.s_version

/*
 * This is the original minix inode layout on disk.
 * Note the 8-bit gid and atime and ctime.
 */
struct minix_inode {
	u16 i_mode;
	u16 i_uid;
	u32 i_size;
	u32 i_time;
	u8  i_gid;
	u8  i_nlinks;
	u16 i_zone[9];
};

/*
 * The new minix inode has all the time entries, as well as
 * long block numbers and a third indirect block (7+1+1+1
 * instead of 7+1+1). Also, some previously 8-bit values are
 * now 16-bit. The inode is now 64 bytes instead of 32.
 */
struct minix2_inode {
	u16 i_mode;
	u16 i_nlinks;
	u16 i_uid;
	u16 i_gid;
	u32 i_size;
	u32 i_atime;
	u32 i_mtime;
	u32 i_ctime;
	u32 i_zone[10];
};

/*
 * minix super-block data on disk
 */
struct minix_super_block {
	u16 s_ninodes;
	u16 s_nzones;
	u16 s_imap_blocks;
	u16 s_zmap_blocks;
	u16 s_firstdatazone;
	u16 s_log_zone_size;
	u32 s_max_size;
	u16 s_magic;
	u16 s_state;
	u32 s_zones;
};

struct minix_dir_entry {
	u16 inode;
	char name[0];
};

#define BLOCK_SIZE_BITS 10
#define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)

#define NAME_MAX         255   /* # chars in a file name */

#define MINIX_INODES_PER_BLOCK ((BLOCK_SIZE)/(sizeof (struct minix_inode)))

#define MINIX_VALID_FS               0x0001          /* Clean fs. */
#define MINIX_ERROR_FS               0x0002          /* fs has errors. */

#define MINIX_SUPER_MAGIC    0x137F          /* original minix fs */
#define MINIX_SUPER_MAGIC2   0x138F          /* minix fs, 30 char names */

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

#ifdef MINIX2_SUPER_MAGIC2
#define HAVE_MINIX2 1
#endif

#ifndef __linux__
#define volatile
#endif

#define ROOT_INO 1

#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 = "fsck.minix";
static char *program_version = "1.2 - 11/11/96";
static char *device_name = NULL;
static int IN;
static int repair = 0, automatic = 0, verbose = 0, list = 0, show =
	0, warn_mode = 0, force = 0;
static int directory = 0, regular = 0, blockdev = 0, chardev = 0, links =
	0, symlinks = 0, total = 0;

static int changed = 0;			/* flags if the filesystem has been changed */
static int errors_uncorrected = 0;	/* flag if some error was not corrected */
static int dirsize = 16;
static int namelen = 14;
static int version2 = 0;
static struct termios termios;
static int termios_set = 0;

/* File-name data */
#define MAX_DEPTH 32
static int name_depth = 0;
// static char name_list[MAX_DEPTH][BUFSIZ + 1];
static char **name_list = NULL;

static char *inode_buffer = NULL;

#define Inode (((struct minix_inode *) inode_buffer)-1)
#define Inode2 (((struct minix2_inode *) inode_buffer)-1)
static char super_block_buffer[BLOCK_SIZE];

#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 char *inode_count = NULL;
static unsigned char *zone_count = NULL;

static void recursive_check(unsigned int ino);
static void recursive_check2(unsigned int ino);

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

#define mark_inode(x) (setbit(inode_map,(x)),changed=1)
#define unmark_inode(x) (clrbit(inode_map,(x)),changed=1)

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

static void leave(int) __attribute__ ((noreturn));
static void leave(int status)
{
	if (termios_set)
		tcsetattr(0, TCSANOW, &termios);
	exit(status);
}

static void show_usage(void)
{
	fprintf(stderr, "BusyBox v%s (%s) multi-call binary -- GPL2\n\n",
			BB_VER, BB_BT);
	fprintf(stderr, "Usage: %s [-larvsmf] /dev/name\n", program_name);
#ifndef BB_FEATURE_TRIVIAL_HELP
	fprintf(stderr,
			"\nPerforms a consistency check for MINIX filesystems.\n\n");
	fprintf(stderr, "Options:\n");
	fprintf(stderr, "\t-l\tLists all filenames\n");
	fprintf(stderr, "\t-r\tPerform interactive repairs\n");
	fprintf(stderr, "\t-a\tPerform automatic repairs\n");
	fprintf(stderr, "\t-v\tverbose\n");
	fprintf(stderr, "\t-s\tOutputs super-block information\n");
	fprintf(stderr,
			"\t-m\tActivates MINIX-like \"mode not cleared\" warnings\n");
	fprintf(stderr, "\t-f\tForce file system check.\n\n");
#endif
	leave(16);
}

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

/*
 * This simply goes through the file-name data and prints out the
 * current file.
 */
static void print_current_name(void)
{
	int i = 0;

	while (i < name_depth)
		printf("/%.*s", namelen, name_list[i++]);
	if (i == 0)
		printf("/");
}

static int ask(const char *string, int def)
{
	int c;

	if (!repair) {
		printf("\n");
		errors_uncorrected = 1;
		return 0;
	}
	if (automatic) {
		printf("\n");
		if (!def)
			errors_uncorrected = 1;
		return def;
	}
	printf(def ? "%s (y/n)? " : "%s (n/y)? ", string);
	for (;;) {
		fflush(stdout);
		if ((c = getchar()) == EOF) {
			if (!def)
				errors_uncorrected = 1;
			return def;
		}
		c = toupper(c);
		if (c == 'Y') {
			def = 1;
			break;
		} else if (c == 'N') {
			def = 0;
			break;
		} else if (c == ' ' || c == '\n')
			break;
	}
	if (def)
		printf("y\n");
	else {
		printf("n\n");
		errors_uncorrected = 1;
	}
	return def;
}

/*
 * Make certain that we aren't checking a filesystem that is on a
 * mounted partition.  Code adapted from e2fsck, Copyright (C) 1993,
 * 1994 Theodore Ts'o.  Also licensed under GPL.
 */
static void check_mount(void)
{
	FILE *f;
	struct mntent *mnt;
	int cont;
	int fd;

	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;

	/*
	 * If the root is mounted read-only, then /etc/mtab is
	 * probably not correct; so we won't issue a warning based on
	 * it.
	 */
	fd = open(MOUNTED, O_RDWR);
	if (fd < 0 && errno == EROFS)
		return;
	else
		close(fd);

	printf("%s is mounted.	 ", device_name);
	if (isatty(0) && isatty(1))
		cont = ask("Do you really want to continue", 0);
	else
		cont = 0;
	if (!cont) {
		printf("check aborted.\n");
		exit(0);
	}
	return;
}

/*
 * check_zone_nr checks to see that *nr is a valid zone nr. If it
 * isn't, it will possibly be repaired. Check_zone_nr sets *corrected
 * if an error was corrected, and returns the zone (0 for no zone
 * or a bad zone-number).
 */
static int check_zone_nr(unsigned short *nr, int *corrected)
{
	if (!*nr)
		return 0;
	if (*nr < FIRSTZONE)
		printf("Zone nr < FIRSTZONE in file `");
	else if (*nr >= ZONES)
		printf("Zone nr >= ZONES in file `");
	else
		return *nr;
	print_current_name();
	printf("'.");
	if (ask("Remove block", 1)) {
		*nr = 0;
		*corrected = 1;
	}
	return 0;
}

#ifdef HAVE_MINIX2
static int check_zone_nr2(unsigned int *nr, int *corrected)
{
	if (!*nr)
		return 0;
	if (*nr < FIRSTZONE)
		printf("Zone nr < FIRSTZONE in file `");
	else if (*nr >= ZONES)
		printf("Zone nr >= ZONES in file `");
	else
		return *nr;
	print_current_name();
	printf("'.");
	if (ask("Remove block", 1)) {
		*nr = 0;
		*corrected = 1;
	}
	return 0;
}
#endif

/*
 * read-block reads block nr into the buffer at addr.
 */
static void read_block(unsigned int nr, char *addr)
{
	if (!nr) {
		memset(addr, 0, BLOCK_SIZE);
		return;
	}
	if (BLOCK_SIZE * nr != lseek(IN, BLOCK_SIZE * nr, SEEK_SET)) {
		printf("Read error: unable to seek to block in file '");
		print_current_name();
		printf("'\n");
		memset(addr, 0, BLOCK_SIZE);
		errors_uncorrected = 1;
	} else if (BLOCK_SIZE != read(IN, addr, BLOCK_SIZE)) {
		printf("Read error: bad block in file '");
		print_current_name();
		printf("'\n");
		memset(addr, 0, BLOCK_SIZE);
		errors_uncorrected = 1;
	}
}

/*
 * write_block writes block nr to disk.
 */
static void write_block(unsigned int nr, char *addr)
{
	if (!nr)
		return;
	if (nr < FIRSTZONE || nr >= ZONES) {
		printf("Internal error: trying to write bad block\n"
			   "Write request ignored\n");
		errors_uncorrected = 1;
		return;
	}
	if (BLOCK_SIZE * nr != lseek(IN, BLOCK_SIZE * nr, SEEK_SET))
		die("seek failed in write_block");
	if (BLOCK_SIZE != write(IN, addr, BLOCK_SIZE)) {
		printf("Write error: bad block in file '");
		print_current_name();
		printf("'\n");
		errors_uncorrected = 1;
	}
}

/*
 * map-block calculates the absolute block nr of a block in a file.
 * It sets 'changed' if the inode has needed changing, and re-writes
 * any indirect blocks with errors.
 */
static int map_block(struct minix_inode *inode, unsigned int blknr)
{
	unsigned short ind[BLOCK_SIZE >> 1];
	unsigned short dind[BLOCK_SIZE >> 1];
	int blk_chg, block, result;

	if (blknr < 7)
		return check_zone_nr(inode->i_zone + blknr, &changed);
	blknr -= 7;
	if (blknr < 512) {
		block = check_zone_nr(inode->i_zone + 7, &changed);
		read_block(block, (char *) ind);
		blk_chg = 0;
		result = check_zone_nr(blknr + ind, &blk_chg);
		if (blk_chg)
			write_block(block, (char *) ind);
		return result;
	}
	blknr -= 512;
	block = check_zone_nr(inode->i_zone + 8, &changed);
	read_block(block, (char *) dind);
	blk_chg = 0;
	result = check_zone_nr(dind + (blknr / 512), &blk_chg);
	if (blk_chg)
		write_block(block, (char *) dind);
	block = result;
	read_block(block, (char *) ind);
	blk_chg = 0;
	result = check_zone_nr(ind + (blknr % 512), &blk_chg);
	if (blk_chg)
		write_block(block, (char *) ind);
	return result;
}

#ifdef HAVE_MINIX2
static int map_block2(struct minix2_inode *inode, unsigned int blknr)
{
	unsigned int ind[BLOCK_SIZE >> 2];
	unsigned int dind[BLOCK_SIZE >> 2];
	unsigned int tind[BLOCK_SIZE >> 2];
	int blk_chg, block, result;

	if (blknr < 7)
		return check_zone_nr2(inode->i_zone + blknr, &changed);
	blknr -= 7;
	if (blknr < 256) {
		block = check_zone_nr2(inode->i_zone + 7, &changed);
		read_block(block, (char *) ind);
		blk_chg = 0;
		result = check_zone_nr2(blknr + ind, &blk_chg);
		if (blk_chg)
			write_block(block, (char *) ind);
		return result;
	}
	blknr -= 256;
	if (blknr >= 256 * 256) {
		block = check_zone_nr2(inode->i_zone + 8, &changed);
		read_block(block, (char *) dind);
		blk_chg = 0;
		result = check_zone_nr2(dind + blknr / 256, &blk_chg);
		if (blk_chg)
			write_block(block, (char *)