source: MondoRescue/branches/stable/mindi-busybox/util-linux/fsck_minix.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * fsck.c - a file system consistency checker for Linux.
 *
 * (C) 1991, 1992 Linus Torvalds.
 *
 * Licensed under GPLv2, see file LICENSE in this tarball for details.
 */

/*
 * 09.11.91  -  made the first rudimentary 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 system-independent.
 *         (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 Mi¶kiewicz <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).
 *
 * Usage: 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 <mntent.h>
#include "libbb.h"
#include "minix.h"

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

enum {
#ifdef UNUSED
    MINIX1_LINK_MAX = 250,
    MINIX2_LINK_MAX = 65530,
    MINIX_I_MAP_SLOTS = 8,
    MINIX_Z_MAP_SLOTS = 64,
    MINIX_V1 = 0x0001,      /* original minix fs */
    MINIX_V2 = 0x0002,      /* minix V2 fs */
#endif
    MINIX_NAME_MAX = 255,         /* # chars in a file name */
};

#if !ENABLE_FEATURE_MINIX2
enum { version2 = 0 };
#endif

enum { MAX_DEPTH = 32 };

struct globals {
    int dev_fd;
#if ENABLE_FEATURE_MINIX2
    smallint version2;
#endif
    smallint repair, automatic, verbose, list, show, warn_mode, force;
    smallint changed;  /* is filesystem modified? */
    smallint errors_uncorrected;  /* flag if some error was not corrected */
    smallint termios_set;
    smallint dirsize;
    smallint namelen;
    char *device_name;
    int directory, regular, blockdev, chardev, links, symlinks, total;
    char *inode_buffer;

    char *inode_map;
    char *zone_map;

    unsigned char *inode_count;
    unsigned char *zone_count;

    /* File-name data */
    int name_depth;
    char *name_component[MAX_DEPTH+1];

    /* Bigger stuff */
    struct termios sv_termios;
    char super_block_buffer[BLOCK_SIZE];
    char add_zone_ind_blk[BLOCK_SIZE];
    char add_zone_dind_blk[BLOCK_SIZE];
    USE_FEATURE_MINIX2(char add_zone_tind_blk[BLOCK_SIZE];)
    char check_file_blk[BLOCK_SIZE];

    /* File-name data */
    char current_name[MAX_DEPTH * MINIX_NAME_MAX];
};

#define G (*ptr_to_globals)
#define dev_fd             (G.dev_fd             )
#if ENABLE_FEATURE_MINIX2
#define version2           (G.version2           )
#endif
#define repair             (G.repair             )
#define automatic          (G.automatic          )
#define verbose            (G.verbose            )
#define list               (G.list               )
#define show               (G.show               )
#define warn_mode          (G.warn_mode          )
#define force              (G.force              )
#define changed            (G.changed            )
#define errors_uncorrected (G.errors_uncorrected )
#define termios_set        (G.termios_set        )
#define dirsize            (G.dirsize            )
#define namelen            (G.namelen            )
#define device_name        (G.device_name        )
#define directory          (G.directory          )
#define regular            (G.regular            )
#define blockdev           (G.blockdev           )
#define chardev            (G.chardev            )
#define links              (G.links              )
#define symlinks           (G.symlinks           )
#define total              (G.total              )
#define inode_buffer       (G.inode_buffer       )
#define inode_map          (G.inode_map          )
#define zone_map           (G.zone_map           )
#define inode_count        (G.inode_count        )
#define zone_count         (G.zone_count         )
#define name_depth         (G.name_depth         )
#define name_component     (G.name_component     )
#define sv_termios         (G.sv_termios         )
#define super_block_buffer (G.super_block_buffer )
#define add_zone_ind_blk   (G.add_zone_ind_blk   )
#define add_zone_dind_blk  (G.add_zone_dind_blk  )
#define add_zone_tind_blk  (G.add_zone_tind_blk  )
#define check_file_blk     (G.check_file_blk     )
#define current_name       (G.current_name       )
#define INIT_G() do { \
    PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
    dirsize = 16; \
    namelen = 14; \
    current_name[0] = '/'; \
    /*current_name[1] = '\0';*/ \
    name_component[0] = &current_name[0]; \
} while (0)

#define Inode1 (((struct minix1_inode *) inode_buffer)-1)
#define Inode2 (((struct minix2_inode *) inode_buffer)-1)

#define Super (*(struct minix_super_block *)(super_block_buffer))

#if ENABLE_FEATURE_MINIX2
# define ZONES    ((unsigned)(version2 ? Super.s_zones : Super.s_nzones))
#else
# define ZONES    ((unsigned)(Super.s_nzones))
#endif
#define INODES    ((unsigned)Super.s_ninodes)
#define IMAPS     ((unsigned)Super.s_imap_blocks)
#define ZMAPS     ((unsigned)Super.s_zmap_blocks)
#define FIRSTZONE ((unsigned)Super.s_firstdatazone)
#define ZONESIZE  ((unsigned)Super.s_log_zone_size)
#define MAXSIZE   ((unsigned)Super.s_max_size)
#define MAGIC     (Super.s_magic)

/* gcc likes this more (code is smaller) than macro variant */
static ALWAYS_INLINE unsigned div_roundup(unsigned size, unsigned n)
{
    return (size + n-1) / n;
}

#if ENABLE_FEATURE_MINIX2
#define INODE_BLOCKS div_roundup(INODES, (version2 ? MINIX2_INODES_PER_BLOCK \
                    : MINIX1_INODES_PER_BLOCK))
#else
#define INODE_BLOCKS div_roundup(INODES, MINIX1_INODES_PER_BLOCK)
#endif

#define INODE_BUFFER_SIZE (INODE_BLOCKS * BLOCK_SIZE)
#define NORM_FIRSTZONE    (2 + IMAPS + ZMAPS + INODE_BLOCKS)

/* Before you ask "where they come from?": */
/* setbit/clrbit are supplied by sys/param.h */

static int minix_bit(const char *a, unsigned i)
{
    return (a[i >> 3] & (1<<(i & 7)));
}

static void minix_setbit(char *a, unsigned i)
{
    setbit(a, i);
    changed = 1;
}
static void minix_clrbit(char *a, unsigned i)
{
    clrbit(a, i);
    changed = 1;
}

/* Note: do not assume 0/1, it is 0/nonzero */
#define zone_in_use(x)  (minix_bit(zone_map,(x)-FIRSTZONE+1))
#define inode_in_use(x) (minix_bit(inode_map,(x)))

#define mark_inode(x)   (minix_setbit(inode_map,(x)))
#define unmark_inode(x) (minix_clrbit(inode_map,(x)))

#define mark_zone(x)    (minix_setbit(zone_map,(x)-FIRSTZONE+1))
#define unmark_zone(x)  (minix_clrbit(zone_map,(x)-FIRSTZONE+1))


static void recursive_check(unsigned ino);
#if ENABLE_FEATURE_MINIX2
static void recursive_check2(unsigned ino);
#endif

static void die(const char *str) ATTRIBUTE_NORETURN;
static void die(const char *str)
{
    if (termios_set)
        tcsetattr(0, TCSANOW, &sv_termios);
    bb_error_msg_and_die("%s", str);
}

static void push_filename(const char *name)
{
    //  /dir/dir/dir/file
    //  ^   ^   ^
    // [0] [1] [2] <-name_component[i]
    if (name_depth < MAX_DEPTH) {
        int len;
        char *p = name_component[name_depth];
        *p++ = '/';
        len = sprintf(p, "%.*s", namelen, name);
        name_component[name_depth + 1] = p + len;
    }
    name_depth++;
}

static void pop_filename(void)
{
    name_depth--;
    if (name_depth < MAX_DEPTH) {
        *name_component[name_depth] = '\0';
        if (!name_depth) {
            current_name[0] = '/';
            current_name[1] = '\0';
        }
    }
}

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

    if (!repair) {
        puts("");
        errors_uncorrected = 1;
        return 0;
    }
    if (automatic) {
        puts("");
        if (!def)
            errors_uncorrected = 1;
        return def;
    }
    printf(def ? "%s (y/n)? " : "%s (n/y)? ", string);
    for (;;) {
        fflush(stdout);
        c = getchar();
        if (c == 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;

    f = setmntent(MOUNTED, "r");
    if (f == 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;
    close(fd);

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

/*
 * 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_nr2(uint32_t *nr, smallint *corrected)
{
    const char *msg;
    if (!*nr)
        return 0;
    if (*nr < FIRSTZONE)
        msg = "< FIRSTZONE";
    else if (*nr >= ZONES)
        msg = ">= ZONES";
    else
        return *nr;
    printf("Zone nr %s in file '%s'. ", msg, current_name);
    if (ask("Remove block", 1)) {
        *nr = 0;
        *corrected = 1;
    }
    return 0;
}

static int check_zone_nr(uint16_t *nr, smallint *corrected)
{
    uint32_t nr32 = *nr;
    int r = check_zone_nr2(&nr32, corrected);
    *nr = (uint16_t)nr32;
    return r;
}

/*
 * read-block reads block nr into the buffer at addr.
 */
static void read_block(unsigned nr, char *addr)
{
    if (!nr) {
        memset(addr, 0, BLOCK_SIZE);
        return;
    }
    if (BLOCK_SIZE * nr != lseek(dev_fd, BLOCK_SIZE * nr, SEEK_SET)) {
        printf("%s: cannot seek to block in file '%s'\n",
                bb_msg_read_error, current_name);
        errors_uncorrected = 1;
        memset(addr, 0, BLOCK_SIZE);
    } else if (BLOCK_SIZE != read(dev_fd, addr, BLOCK_SIZE)) {
        printf("%s: bad block in file '%s'\n",
                bb_msg_read_error, current_name);
        errors_uncorrected = 1;
        memset(addr, 0, BLOCK_SIZE);
    }
}

/*
 * write_block writes block nr to disk.
 */
static void write_block(unsigned 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(dev_fd, BLOCK_SIZE * nr, SEEK_SET))
        die("seek failed in write_block");
    if (BLOCK_SIZE != write(dev_fd, addr, BLOCK_SIZE)) {
        printf("%s: bad block in file '%s'\n",
                bb_msg_write_error, current_name);
        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 minix1_inode *inode, unsigned blknr)
{
    uint16_t ind[BLOCK_SIZE >> 1];
    uint16_t dind[BLOCK_SIZE >> 1];
    int block, result;
    smallint blk_chg;

    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;
}

#if ENABLE_FEATURE_MINIX2
static int map_block2(struct minix2_inode *inode, unsigned blknr)
{
    uint32_t ind[BLOCK_SIZE >> 2];
    uint32_t dind[BLOCK_SIZE >> 2];
    uint32_t tind[BLOCK_SIZE >> 2];
    int block, result;
    smallint blk_chg;

    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 *) dind);
        block = result;
        read_block(block, (char *) ind);
        blk_chg = 0;
        result = check_zone_nr2(ind + blknr % 256, &blk_chg);
        if (blk_chg)
            write_block(block, (char *) ind);
        return result;
    }
    blknr -= 256 * 256;
    block = check_zone_nr2(inode->i_zone + 9, &changed);
    read_block(block, (char *) tind);
    blk_chg = 0;
    result = check_zone_nr2(tind + blknr / (256 * 256), &blk_chg);
    if (blk_chg)
        write_block(block, (char *) tind);
    block = result;
    read_block(block, (char *) dind);
    blk_chg = 0;
    result = check_zone_nr2(dind + (blknr / 256) % 256, &blk_chg);
    if (blk_chg)
        write_block(block, (char *) dind);
    block = result;
    read_block(block, (char *) ind);
    blk_chg = 0;
    result = check_zone_nr2(ind + blknr % 256, &blk_chg);
    if (blk_chg)
        write_block(block, (char *) ind);
    return result;
}
#endif

static void write_super_block(void)
{
    /*
     * Set the state of the filesystem based on whether or not there
     * are uncorrected errors.  The filesystem valid flag is
     * unconditionally set if we get this far.
     */
    Super.s_state |= MINIX_VALID_FS | MINIX_ERROR_FS;
    if (!errors_uncorrected)
        Super.s_state &= ~MINIX_ERROR_FS;

    if (BLOCK_SIZE != lseek(dev_fd, BLOCK_SIZE, SEEK_SET))
        die("seek failed in write_super_block");
    if (BLOCK_SIZE != write(dev_fd, super_block_buffer, BLOCK_SIZE))
        die("cannot write super-block");
}

static void write_tables(void)
{
    write_super_block();

    if (IMAPS * BLOCK_SIZE != write(dev_fd, inode_map, IMAPS * BLOCK_SIZE))
        die("cannot write inode map");
    if (ZMAPS * BLOCK_SIZE != write(dev_fd, zone_map, ZMAPS * BLOCK_SIZE))
        die("cannot write zone map");
    if (INODE_BUFFER_SIZE != write(dev_fd, inode_buffer, INODE_BUFFER_SIZE))
        die("cannot write inodes");
}

static void get_dirsize(void)
{
    int block;
    char blk[BLOCK_SIZE];
    int size;

#if ENABLE_FEATURE_MINIX2
    if (version2)
        block = Inode2[MINIX_ROOT_INO].i_zone[0];
    else
#endif
        block = Inode1[MINIX_ROOT_INO].i_zone[0];
    read_block(block, blk);
    for (size = 16; size < BLOCK_SIZE; size <<= 1) {
        if (strcmp(blk + size + 2, "..") == 0) {
            dirsize = size;
            namelen = size - 2;
            return;
        }
    }
    /* use defaults */
}

static void read_superblock(void)
{
    if (BLOCK_SIZE != lseek(dev_fd, BLOCK_SIZE, SEEK_SET))
        die("seek failed");
    if (BLOCK_SIZE != read(dev_fd, super_block_buffer, BLOCK_SIZE))
        die("cannot read super block");
    /* already initialized to:
    namelen = 14;
    dirsize = 16;
    version2 = 0;
    */
    if (MAGIC == MINIX1_SUPER_MAGIC) {
    } else if (MAGIC == MINIX1_SUPER_MAGIC2) {
        namelen = 30;
        dirsize = 32;
#if ENABLE_FEATURE_MINIX2
    } else if (MAGIC == MINIX2_SUPER_MAGIC) {
        version2 = 1;
    } else if (MAGIC == MINIX2_SUPER_MAGIC2) {
        namelen = 30;
        dirsize = 32;
        version2 = 1;
#endif
    } else
        die("bad magic number in super-block");
    if (ZONESIZE != 0 || BLOCK_SIZE != 1024)
        die("only 1k blocks/zones supported");
    if (IMAPS * BLOCK_SIZE * 8 < INODES + 1)
        die("bad s_imap_blocks field in super-block");
    if (ZMAPS * BLOCK_SIZE * 8 < ZONES - FIRSTZONE + 1)
        die("bad s_zmap_blocks field in super-block");
}

static void read_tables(void)
{
    inode_map = xzalloc(IMAPS * BLOCK_SIZE);
    zone_map = xzalloc(ZMAPS * BLOCK_SIZE);
    inode_buffer = xmalloc(INODE_BUFFER_SIZE);
    inode_count = xmalloc(INODES + 1);
    zone_count = xmalloc(ZONES);
    if (IMAPS * BLOCK_SIZE != read(dev_fd, inode_map, IMAPS * BLOCK_SIZE))
        die("cannot read inode map");
    if (ZMAPS * BLOCK_SIZE != read(dev_fd, zone_map, ZMAPS * BLOCK_SIZE))
        die("cannot read zone map");
    if (INODE_BUFFER_SIZE != read(dev_fd, inode_buffer, INODE_BUFFER_SIZE))
        die("cannot read inodes");
    if (NORM_FIRSTZONE != FIRSTZONE) {
        printf("warning: firstzone!=norm_firstzone\n");
        errors_uncorrected = 1;
    }
    get_dirsize();
    if (show) {
        printf("%u inodes\n"
            "%u blocks\n"
            "Firstdatazone=%u (%u)\n"
            "Zonesize=%u\n"
            "Maxsize=%u\n"
            "Filesystem state=%u\n"
            "namelen=%u\n\n",
            INODES,
            ZONES,
            FIRSTZONE, NORM_FIRSTZONE,
            BLOCK_SIZE << ZONESIZE,
            MAXSIZE,
            Super.s_state,
            namelen);
    }
}

static struct minix1_inode *get_inode(unsigned nr)
{
    struct minix1_inode *inode;

    if (!nr || nr > INODES)
        return NULL;
    total++;
    inode = Inode1 + nr;
    if (!inode_count[nr]) {
        if (!inode_in_use(nr)) {
            printf("Inode %d is marked as 'unused', but it is used "
                    "for file '%s'\n", nr, current_name);
            if (repair) {
                if (ask("Mark as 'in use'", 1))
                    mark_inode(nr);
                else
                    errors_uncorrected = 1;
            }
        }
        if (S_ISDIR(inode->i_mode))
            directory++;
        else if (S_ISREG(inode->i_mode))
            regular++;
        else if (S_ISCHR(inode->i_mode))
            chardev++;
        else if (S_ISBLK(inode->i_mode))
            blockdev++;
        else if (S_ISLNK(inode->i_mode))
            symlinks++;
        else if (S_ISSOCK(inode->i_mode));
        else if (S_ISFIFO(inode->i_mode));
        else {
            printf("%s has mode %05o\n", current_name, inode->i_mode);
        }

    } else
        links++;
    if (!++inode_count[nr]) {
        printf("Warning: inode count too big\n");
        inode_count[nr]--;
        errors_uncorrected = 1;
    }
    return inode;
}

#if ENABLE_FEATURE_MINIX2
static struct minix2_inode *get_inode2(unsigned nr)
{
    struct minix2_inode *inode;

    if (!nr || nr > INODES)
        return NULL;
    total++;
    inode = Inode2 + nr;
    if (!inode_count[nr]) {
        if (!inode_in_use(nr)) {
            printf("Inode %d is marked as 'unused', but it is used "
                    "for file '%s'\n", nr, current_name);
            if (repair) {
                if (ask("Mark as 'in use'", 1))
                    mark_inode(nr);
                else
                    errors_uncorrected = 1;
            }
        }
        if (S_ISDIR(inode->i_mode))
            directory++;
        else if (S_ISREG(inode->i_mode))
            regular++;
        else if (S_ISCHR(inode->i_mode))
            chardev++;
        else if (S_ISBLK(inode->i_mode))
            blockdev++;
        else if (S_ISLNK(inode->i_mode))
            symlinks++;
        else if (S_ISSOCK(inode->i_mode));
        else if (S_ISFIFO(inode->i_mode));
        else {
            printf("%s has mode %05o\n", current_name, inode->i_mode);
        }
    } else
        links++;
    if (!++inode_count[nr]) {
        printf("Warning: inode count too big\n");
        inode_count[nr]--;
        errors_uncorrected = 1;
    }
    return inode;
}
#endif

static void check_root(void)
{
    struct minix1_inode *inode = Inode1 + MINIX_ROOT_INO;

    if (!inode || !S_ISDIR(inode->i_mode))
        die("root inode isn't a directory");
}

#if ENABLE_FEATURE_MINIX2
static void check_root2(void)
{
    struct minix2_inode *inode = Inode2 + MINIX_ROOT_INO;

    if (!inode || !S_ISDIR(inode->i_mode))
        die("root inode isn't a directory");
}
#else
void check_root2(void);
#endif

static int add_zone(uint16_t *znr, smallint *corrected)
{
    int result;
    int block;

    result = 0;
    block = check_zone_nr(znr, corrected);
    if (!block)
        return 0;
    if (zone_count[block]) {
        printf("Already used block is reused in file '%s'. ",
                current_name);
        if (ask("Clear", 1)) {
            *znr = 0;
            block = 0;
            *corrected = 1;
            return 0;
        }
    }
    if (!zone_in_use(block)) {
        printf("Block %d in file '%s' is marked as 'unused'. ",
                block, current_name);
        if (ask("Correct", 1))
            mark_zone(block);
    }
    if (!++zone_count[block])
        zone_count[block]--;
    return block;
}

#if ENABLE_FEATURE_MINIX2
static int add_zone2(uint32_t *znr, smallint *corrected)
{
    int result;
    int block;

    result = 0;
    block = check_zone_nr2(znr, corrected);
    if (!block)
        return 0;
    if (zone_count[block]) {
        printf("Already used block is reused in file '%s'. ",
                current_name);
        if (ask("Clear", 1)) {
            *znr = 0;
            block = 0;
            *corrected = 1;
            return 0;
        }
    }
    if (!zone_in_use(block)) {
        printf("Block %d in file '%s' is marked as 'unused'. ",
                block, current_name);
        if (ask("Correct", 1))
            mark_zone(block);
    }
    if (!++zone_count[block])
        zone_count[block]--;
    return block;
}
#endif

static void add_zone_ind(uint16_t *znr, smallint *corrected)
{
    int i;
    int block;
    smallint chg_blk = 0;

    block = add_zone(znr, corrected);
    if (!block)
        return;
    read_block(block, add_zone_ind_blk);
    for (i = 0; i < (BLOCK_SIZE >> 1); i++)
        add_zone(i + (uint16_t *) add_zone_ind_blk, &chg_blk);
    if (chg_blk)
        write_block(block, add_zone_ind_blk);
}

#if ENABLE_FEATURE_MINIX2
static void add_zone_ind2(uint32_t *znr, smallint *corrected)
{
    int i;
    int block;
    smallint chg_blk = 0;

    block = add_zone2(znr, corrected);
    if (!block)
        return;
    read_block(block, add_zone_ind_blk);
    for (i = 0; i < BLOCK_SIZE >> 2; i++)
        add_zone2(i + (uint32_t *) add_zone_ind_blk, &chg_blk);
    if (chg_blk)
        write_block(block, add_zone_ind_blk);
}
#endif

static void add_zone_dind(uint16_t *znr, smallint *corrected)
{
    int i;
    int block;
    smallint chg_blk = 0;

    block = add_zone(znr, corrected);
    if (!block)
        return;
    read_block(block, add_zone_dind_blk);
    for (i = 0; i < (BLOCK_SIZE >> 1); i++)
        add_zone_ind(i + (uint16_t *) add_zone_dind_blk, &chg_blk);
    if (chg_blk)
        write_block(block, add_zone_dind_blk);
}

#if ENABLE_FEATURE_MINIX2
static void add_zone_dind2(uint32_t *znr, smallint *corrected)
{
    int i;
    int block;
    smallint chg_blk = 0;

    block = add_zone2(znr, corrected);
    if (!block)
        return;
    read_block(block, add_zone_dind_blk);
    for (i = 0; i < BLOCK_SIZE >> 2; i++)
        add_zone_ind2(i + (uint32_t *) add_zone_dind_blk, &chg_blk);
    if (chg_blk)
        write_block(block, add_zone_dind_blk);
}

static void add_zone_tind2(uint32_t *znr, smallint *corrected)
{
    int i;
    int block;
    smallint chg_blk = 0;

    block = add_zone2(znr, corrected);
    if (!block)
        return;
    read_block(block, add_zone_tind_blk);
    for (i = 0; i < BLOCK_SIZE >> 2; i++)
        add_zone_dind2(i + (uint32_t *) add_zone_tind_blk, &chg_blk);
    if (chg_blk)
        write_block(block, add_zone_tind_blk);
}
#endif

static void check_zones(unsigned i)
{
    struct minix1_inode *inode;

    if (!i || i > INODES)
        return;
    if (inode_count[i] > 1)     /* have we counted this file already? */
        return;
    inode = Inode1 + i;
    if (!S_ISDIR(inode->i_mode) && !S_ISREG(inode->i_mode) &&
        !S_ISLNK(inode->i_mode)) return;
    for (i = 0; i < 7; i++)
        add_zone(i + inode->i_zone, &changed);
    add_zone_ind(7 + inode->i_zone, &changed);
    add_zone_dind(8 + inode->i_zone, &changed);
}

#if ENABLE_FEATURE_MINIX2
static void check_zones2(unsigned i)
{
    struct minix2_inode *inode;

    if (!i || i > INODES)
        return;
    if (inode_count[i] > 1)     /* have we counted this file already? */
        return;
    inode = Inode2 + i;
    if (!S_ISDIR(inode->i_mode) && !S_ISREG(inode->i_mode)
        && !S_ISLNK(inode->i_mode))
        return;
    for (i = 0; i < 7; i++)
        add_zone2(i + inode->i_zone, &changed);
    add_zone_ind2(7 + inode->i_zone, &changed);
    add_zone_dind2(8 + inode->i_zone, &changed);
    add_zone_tind2(9 + inode->i_zone, &changed);
}
#endif

static void check_file(struct minix1_inode *dir, unsigned offset)
{
    struct minix1_inode *inode;
    int ino;
    char *name;
    int block;

    block = map_block(dir, offset / BLOCK_SIZE);
    read_block(block, check_file_blk);
    name = check_file_blk + (offset % BLOCK_SIZE) + 2;
    ino = *(uint16_t *) (name - 2);
    if (ino > INODES) {
        printf("%s contains a bad inode number for file '%.*s'. ",
                current_name, namelen, name);
        if (ask("Remove", 1)) {
            *(uint16_t *) (name - 2) = 0;
            write_block(block, check_file_blk);
        }
        ino = 0;
    }
    push_filename(name);
    inode = get_inode(ino);
    pop_filename();
    if (!offset) {
        if (inode && LONE_CHAR(name, '.'))
            return;
        printf("%s: bad directory: '.' isn't first\n", current_name);
        errors_uncorrected = 1;
    }
    if (offset == dirsize) {
        if (inode && strcmp("..", name) == 0)
            return;
        printf("%s: bad directory: '..' isn't second\n", current_name);
        errors_uncorrected = 1;
    }
    if (!inode)
        return;
    push_filename(name);
    if (list) {
        if (verbose)
            printf("%6d %07o %3d ", ino, inode->i_mode, inode->i_nlinks);
        printf("%s%s\n", current_name, S_ISDIR(inode->i_mode) ? ":" : "");
    }
    check_zones(ino);
    if (inode && S_ISDIR(inode->i_mode))
        recursive_check(ino);
    pop_filename();
}

#if ENABLE_FEATURE_MINIX2
static void check_file2(struct minix2_inode *dir, unsigned offset)
{
    struct minix2_inode *inode;
    int ino;
    char *name;
    int block;

    block = map_block2(dir, offset / BLOCK_SIZE);
    read_block(block, check_file_blk);
    name = check_file_blk + (offset % BLOCK_SIZE) + 2;
    ino = *(uint16_t *) (name - 2);
    if (ino > INODES) {
        printf("%s contains a bad inode number for file '%.*s'. ",
                current_name, namelen, name);
        if (ask("Remove", 1)) {
            *(uint16_t *) (name - 2) = 0;
            write_block(block, check_file_blk);
        }
        ino = 0;
    }
    push_filename(name);
    inode = get_inode2(ino);
    pop_filename();
    if (!offset) {
        if (inode && LONE_CHAR(name, '.'))
            return;
        printf("%s: bad directory: '.' isn't first\n", current_name);
        errors_uncorrected = 1;
    }
    if (offset == dirsize) {
        if (inode && strcmp("..", name) == 0)
            return;
        printf("%s: bad directory: '..' isn't second\n", current_name);
        errors_uncorrected = 1;
    }
    if (!inode)
        return;
    push_filename(name);
    if (list) {
        if (verbose)
            printf("%6d %07o %3d ", ino, inode->i_mode, inode->i_nlinks);
        printf("%s%s\n", current_name, S_ISDIR(inode->i_mode) ? ":" : "");
    }
    check_zones2(ino);
    if (inode && S_ISDIR(inode->i_mode))
        recursive_check2(ino);
    pop_filename();
}
#endif

static void recursive_check(unsigned ino)
{
    struct minix1_inode *dir;
    unsigned offset;

    dir = Inode1 + ino;
    if (!S_ISDIR(dir->i_mode))
        die("internal error");
    if (dir->i_size < 2 * dirsize) {
        printf("%s: bad directory: size<32", current_name);
        errors_uncorrected = 1;
    }
    for (offset = 0; offset < dir->i_size; offset += dirsize)
        check_file(dir, offset);
}

#if ENABLE_FEATURE_MINIX2
static void recursive_check2(unsigned ino)
{
    struct minix2_inode *dir;
    unsigned offset;

    dir = Inode2 + ino;
    if (!S_ISDIR(dir->i_mode))
        die("internal error");
    if (dir->i_size < 2 * dirsize) {
        printf("%s: bad directory: size<32", current_name);
        errors_uncorrected = 1;
    }
    for (offset = 0; offset < dir->i_size; offset += dirsize)
        check_file2(dir, offset);
}
#endif

static int bad_zone(int i)
{
    char buffer[BLOCK_SIZE];

    if (BLOCK_SIZE * i != lseek(dev_fd, BLOCK_SIZE * i, SEEK_SET))
        die("seek failed in bad_zone");
    return (BLOCK_SIZE != read(dev_fd, buffer, BLOCK_SIZE));
}

static void check_counts(void)
{
    int i;

    for (i = 1; i <= INODES; i++) {
        if (warn_mode && Inode1[i].i_mode && !inode_in_use(i)) {
            printf("Inode %d has non-zero mode. ", i);
            if (ask("Clear", 1)) {
                Inode1[i].i_mode = 0;
                changed = 1;
            }
        }
        if (!inode_count[i]) {
            if (!inode_in_use(i))
                continue;
            printf("Unused inode %d is marked as 'used' in the bitmap. ", i);
            if (ask("Clear", 1))
                unmark_inode(i);
            continue;
        }
        if (!inode_in_use(i)) {
            printf("Inode %d is used, but marked as 'unused' in the bitmap. ", i);
            if (ask("Set", 1))
                mark_inode(i);
        }
        if (Inode1[i].i_nlinks != inode_count[i]) {
            printf("Inode %d (mode=%07o), i_nlinks=%d, counted=%d. ",
                i, Inode1[i].i_mode, Inode1[i].i_nlinks,
                inode_count[i]);
            if (ask("Set i_nlinks to count", 1)) {
                Inode1[i].i_nlinks = inode_count[i];
                changed = 1;
            }
        }
    }
    for (i = FIRSTZONE; i < ZONES; i++) {
        if ((zone_in_use(i) != 0) == zone_count[i])
            continue;
        if (!zone_count[i]) {
            if (bad_zone(i))
                continue;
            printf("Zone %d is marked 'in use', but no file uses it. ", i);
            if (ask("Unmark", 1))
                unmark_zone(i);
            continue;
        }
        printf("Zone %d: %sin use, counted=%d\n",
               i, zone_in_use(i) ? "" : "not ", zone_count[i]);
    }
}

#if ENABLE_FEATURE_MINIX2
static void check_counts2(void)
{
    int i;

    for (i = 1; i <= INODES; i++) {
        if (warn_mode && Inode2[i].i_mode && !inode_in_use(i)) {
            printf("Inode %d has non-zero mode. ", i);
            if (ask("Clear", 1)) {
                Inode2[i].i_mode = 0;
                changed = 1;
            }
        }
        if (!inode_count[i]) {
            if (!inode_in_use(i))
                continue;
            printf("Unused inode %d is marked as 'used' in the bitmap. ", i);
            if (ask("Clear", 1))
                unmark_inode(i);
            continue;
        }
        if (!inode_in_use(i)) {
            printf("Inode %d is used, but marked as 'unused' in the bitmap. ", i);
            if (ask("Set", 1))
                mark_inode(i);
        }
        if (Inode2[i].i_nlinks != inode_count[i]) {
            printf("Inode %d (mode=%07o), i_nlinks=%d, counted=%d. ",
                i, Inode2[i].i_mode, Inode2[i].i_nlinks,
                inode_count[i]);
            if (ask("Set i_nlinks to count", 1)) {
                Inode2[i].i_nlinks = inode_count[i];
                changed = 1;
            }
        }
    }
    for (i = FIRSTZONE; i < ZONES; i++) {
        if ((zone_in_use(i) != 0) == zone_count[i])
            continue;
        if (!zone_count[i]) {
            if (bad_zone(i))
                continue;
            printf("Zone %d is marked 'in use', but no file uses it. ", i);
            if (ask("Unmark", 1))
                unmark_zone(i);
            continue;
        }
        printf("Zone %d: %sin use, counted=%d\n",
               i, zone_in_use(i) ? "" : "not ", zone_count[i]);
    }
}
#endif

static void check(void)
{
    memset(inode_count, 0, (INODES + 1) * sizeof(*inode_count));
    memset(zone_count, 0, ZONES * sizeof(*zone_count));
    check_zones(MINIX_ROOT_INO);
    recursive_check(MINIX_ROOT_INO);
    check_counts();
}

#if ENABLE_FEATURE_MINIX2
static void check2(void)
{
    memset(inode_count, 0, (INODES + 1) * sizeof(*inode_count));
    memset(zone_count, 0, ZONES * sizeof(*zone_count));
    check_zones2(MINIX_ROOT_INO);
    recursive_check2(MINIX_ROOT_INO);
    check_counts2();
}
#else
void check2(void);
#endif

int fsck_minix_main(int argc, char **argv);
int fsck_minix_main(int argc, char **argv)
{
    struct termios tmp;
    int retcode = 0;

    xfunc_error_retval = 8;

    INIT_G();

    if (INODE_SIZE1 * MINIX1_INODES_PER_BLOCK != BLOCK_SIZE)
        die("bad inode size");
#if ENABLE_FEATURE_MINIX2
    if (INODE_SIZE2 * MINIX2_INODES_PER_BLOCK != BLOCK_SIZE)
        die("bad v2 inode size");
#endif
    while (--argc != 0) {
        argv++;
        if (argv[0][0] != '-') {
            if (device_name)
                bb_show_usage();
            device_name = argv[0];
        } else {
            while (*++argv[0]) {
                switch (argv[0][0]) {
                case 'l':
                    list = 1;
                    break;
                case 'a':
                    automatic = 1;
                    repair = 1;
                    break;
                case 'r':
                    automatic = 0;
                    repair = 1;
                    break;
                case 'v':
                    verbose = 1;
                    break;
                case 's':
                    show = 1;
                    break;
                case 'm':
                    warn_mode = 1;
                    break;
                case 'f':
                    force = 1;
                    break;
                default:
                    bb_show_usage();
                }
            }
        }
    }
    if (!device_name)
        bb_show_usage();

    check_mount();              /* trying to check a mounted filesystem? */
    if (repair && !automatic) {
        if (!isatty(0) || !isatty(1))
            die("need terminal for interactive repairs");
    }
    dev_fd = xopen(device_name, repair ? O_RDWR : O_RDONLY);

    /*sync(); paranoia? */
    read_superblock();

    /*
     * Determine whether or not we should continue with the checking.
     * This is based on the status of the filesystem valid and error
     * flags and whether or not the -f switch was specified on the
     * command line.
     */
    printf("%s: %s\n", applet_name, bb_banner);

    if (!(Super.s_state & MINIX_ERROR_FS)
     && (Super.s_state & MINIX_VALID_FS) && !force
    ) {
        if (repair)
            printf("%s is clean, check is skipped\n", device_name);
        return 0;
    } else if (force)
        printf("Forcing filesystem check on %s\n", device_name);
    else if (repair)
        printf("Filesystem on %s is dirty, needs checking\n",
               device_name);

    read_tables();

    if (repair && !automatic) {
        tcgetattr(0, &sv_termios);
        tmp = sv_termios;
        tmp.c_lflag &= ~(ICANON | ECHO);
        tcsetattr(0, TCSANOW, &tmp);
        termios_set = 1;
    }

    if (version2) {
        check_root2();
        check2();
    } else {
        check_root();
        check();
    }

    if (verbose) {
        int i, free_cnt;

        for (i = 1, free_cnt = 0; i <= INODES; i++)
            if (!inode_in_use(i))
                free_cnt++;
        printf("\n%6u inodes used (%u%%)\n", (INODES - free_cnt),
               100 * (INODES - free_cnt) / INODES);
        for (i = FIRSTZONE, free_cnt = 0; i < ZONES; i++)
            if (!zone_in_use(i))
                free_cnt++;
        printf("%6u zones used (%u%%)\n\n"
               "%6u regular files\n"
               "%6u directories\n"
               "%6u character device files\n"
               "%6u block device files\n"
               "%6u links\n"
               "%6u symbolic links\n"
               "------\n"
               "%6u files\n",
               (ZONES - free_cnt), 100 * (ZONES - free_cnt) / ZONES,
               regular, directory, chardev, blockdev,
               links - 2 * directory + 1, symlinks,
               total - 2 * directory + 1);
    }
    if (changed) {
        write_tables();
        printf("FILE SYSTEM HAS BEEN CHANGED\n");
        sync();
    } else if (repair)
        write_super_block();

    if (repair && !automatic)
        tcsetattr(0, TCSANOW, &sv_termios);

    if (changed)
        retcode += 3;
    if (errors_uncorrected)
        retcode += 4;
    return retcode;
}