/* 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
 *                           superblock 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 Mickiewicz <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 superblock 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

struct BUG_bad_inode_size {
        char BUG_bad_inode1_size[(INODE_SIZE1 * MINIX1_INODES_PER_BLOCK != BLOCK_SIZE) ? -1 : 1];
#if ENABLE_FEATURE_MINIX2
        char BUG_bad_inode2_size[(INODE_SIZE2 * MINIX2_INODES_PER_BLOCK != BLOCK_SIZE) ? -1 : 1];
#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 };

enum { dev_fd = 3 };

struct globals {
#if ENABLE_FEATURE_MINIX2
        smallint version2;
#endif
        smallint changed;  /* is filesystem modified? */
        smallint errors_uncorrected;  /* flag if some error was not corrected */
        smallint termios_set;
        smallint dirsize;
        smallint namelen;
        const 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 superblock_buffer[BLOCK_SIZE];
        char add_zone_ind_blk[BLOCK_SIZE];
        char add_zone_dind_blk[BLOCK_SIZE];
        IF_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)
#if ENABLE_FEATURE_MINIX2
#define version2           (G.version2           )
#endif
#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 superblock_buffer  (G.superblock_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 { \
        SET_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 OPTION_STR "larvsmf"
enum {
        OPT_l = (1 << 0),
        OPT_a = (1 << 1),
        OPT_r = (1 << 2),
        OPT_v = (1 << 3),
        OPT_s = (1 << 4),
        OPT_w = (1 << 5),
        OPT_f = (1 << 6),
};
#define OPT_list      (option_mask32 & OPT_l)
#define OPT_automatic (option_mask32 & OPT_a)
#define OPT_repair    (option_mask32 & OPT_r)
#define OPT_verbose   (option_mask32 & OPT_v)
#define OPT_show      (option_mask32 & OPT_s)
#define OPT_warn_mode (option_mask32 & OPT_w)
#define OPT_force     (option_mask32 & OPT_f)
/* non-automatic repairs requested? */
#define OPT_manual    ((option_mask32 & (OPT_a|OPT_r)) == OPT_r)


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

#define Super (*(struct minix_superblock *)(superblock_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, MINIX1_INODES_PER_BLOCK)
#else
#define INODE_BLOCKS            div_roundup(INODES, \
                                (version2 ? MINIX2_INODES_PER_BLOCK : 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) NORETURN;
static void die(const char *str)
{
        if (termios_set)
                tcsetattr_stdin_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 (!OPT_repair) {
                bb_putchar('\n');
                errors_uncorrected = 1;
                return 0;
        }
        if (OPT_automatic) {
                bb_putchar('\n');
                if (!def)
                        errors_uncorrected = 1;
                return def;
        }
        printf(def ? "%s (y/n)? " : "%s (n/y)? ", string);
        for (;;) {
                fflush_all();
                c = getchar();
                if (c == EOF) {
                        if (!def)
                                errors_uncorrected = 1;
                        return def;
                }
                if (c == '\n')
                        break;
                c |= 0x20; /* tolower */
                if (c == 'y') {
                        def = 1;
                        break;
                }
                if (c == 'n') {
                        def = 0;
                        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)
{
        if (find_mount_point(device_name, 0)) {
                int cont;
#if ENABLE_FEATURE_MTAB_SUPPORT
                /*
                 * If the root is mounted read-only, then /etc/mtab is
                 * probably not correct; so we won't issue a warning based on
                 * it.
                 */
                int fd = open(bb_path_mtab_file, O_RDWR);

                if (fd < 0 && errno == EROFS)
                        return;
                close(fd);
#endif
                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(EXIT_SUCCESS);
                }
        }
}

/*
 * 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, void *addr)
{
        if (!nr) {
                memset(addr, 0, BLOCK_SIZE);
                return;
        }
        xlseek(dev_fd, BLOCK_SIZE * nr, SEEK_SET);
        if (BLOCK_SIZE != full_read(dev_fd, addr, BLOCK_SIZE)) {
                printf("%s: bad block %u in file '%s'\n",
                                bb_msg_read_error, nr, current_name);
                errors_uncorrected = 1;
                memset(addr, 0, BLOCK_SIZE);
        }
}

/*
 * write_block writes block nr to disk.
 */
static void write_block(unsigned nr, void *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;
        }
        xlseek(dev_fd, BLOCK_SIZE * nr, SEEK_SET);
        if (BLOCK_SIZE != full_write(dev_fd, addr, BLOCK_SIZE)) {
                printf("%s: bad block %u in file '%s'\n",
                                bb_msg_write_error, nr, 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];
        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);
                goto common;
        }
        blknr -= 512;
        block = check_zone_nr(inode->i_zone + 8, &changed);
        read_block(block, ind); /* double indirect */
        blk_chg = 0;
        result = check_zone_nr(&ind[blknr / 512], &blk_chg);
        if (blk_chg)
                write_block(block, ind);
        block = result;
 common:
        read_block(block, ind);
        blk_chg = 0;
        result = check_zone_nr(&ind[blknr % 512], &blk_chg);
        if (blk_chg)
                write_block(block, ind);
        return result;
}

#if ENABLE_FEATURE_MINIX2
static int map_block2(struct minix2_inode *inode, unsigned blknr)
{
        uint32_t ind[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);
                goto common2;
        }
        blknr -= 256;
        if (blknr < 256 * 256) {
                block = check_zone_nr2(inode->i_zone + 8, &changed);
                goto common1;
        }
        blknr -= 256 * 256;
        block = check_zone_nr2(inode->i_zone + 9, &changed);
        read_block(block, ind); /* triple indirect */
        blk_chg = 0;
        result = check_zone_nr2(&ind[blknr / (256 * 256)], &blk_chg);
        if (blk_chg)
                write_block(block, ind);
        block = result;
 common1:
        read_block(block, ind); /* double indirect */
        blk_chg = 0;
        result = check_zone_nr2(&ind[(blknr / 256) % 256], &blk_chg);
        if (blk_chg)
                write_block(block, ind);
        block = result;
 common2:
        read_block(block, ind);
        blk_chg = 0;
        result = check_zone_nr2(&ind[blknr % 256], &blk_chg);
        if (blk_chg)
                write_block(block, ind);
        return result;
}
#endif

static void write_superblock(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;

        xlseek(dev_fd, BLOCK_SIZE, SEEK_SET);
        if (BLOCK_SIZE != full_write(dev_fd, superblock_buffer, BLOCK_SIZE))
                die("can't write superblock");
}

static void write_tables(void)
{
        write_superblock();

        if (IMAPS * BLOCK_SIZE != write(dev_fd, inode_map, IMAPS * BLOCK_SIZE))
                die("can't write inode map");
        if (ZMAPS * BLOCK_SIZE != write(dev_fd, zone_map, ZMAPS * BLOCK_SIZE))
                die("can't write zone map");
        if (INODE_BUFFER_SIZE != write(dev_fd, inode_buffer, INODE_BUFFER_SIZE))
                die("can't 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)
{
        xlseek(dev_fd, BLOCK_SIZE, SEEK_SET);
        if (BLOCK_SIZE != full_read(dev_fd, superblock_buffer, BLOCK_SIZE))
                die("can't read superblock");
        /* 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 superblock");
        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 superblock");
        if (ZMAPS * BLOCK_SIZE * 8 < ZONES - FIRSTZONE + 1)
                die("bad s_zmap_blocks field in superblock");
}

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("can't read inode map");
        if (ZMAPS * BLOCK_SIZE != read(dev_fd, zone_map, ZMAPS * BLOCK_SIZE))
                die("can't read zone map");
        if (INODE_BUFFER_SIZE != read(dev_fd, inode_buffer, INODE_BUFFER_SIZE))
                die("can't read inodes");
        if (NORM_FIRSTZONE != FIRSTZONE) {
                printf("warning: firstzone!=norm_firstzone\n");
                errors_uncorrected = 1;
        }
        get_dirsize();
        if (OPT_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 void get_inode_common(unsigned nr, uint16_t i_mode)
{
        total++;
        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 (OPT_repair) {
                                if (ask("Mark as 'in use'", 1))
                                        mark_inode(nr);
                                else
                                        errors_uncorrected = 1;
                        }
                }
                if (S_ISDIR(i_mode))
                        directory++;
                else if (S_ISREG(i_mode))
                        regular++;
                else if (S_ISCHR(i_mode))
                        chardev++;
                else if (S_ISBLK(i_mode))
                        blockdev++;
                else if (S_ISLNK(i_mode))
                        symlinks++;
                else if (S_ISSOCK(i_mode));
                else if (S_ISFIFO(i_mode));
                else {
                        printf("%s has mode %05o\n", current_name, i_mode);
                }
        } else
                links++;
        if (!++inode_count[nr]) {
                printf("Warning: inode count too big\n");
                inode_count[nr]--;
                errors_uncorrected = 1;
        }
}

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

        if (!nr || nr > INODES)
                return NULL;
        inode = Inode1 + nr;
        get_inode_common(nr, inode->i_mode);
        return inode;
}

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

        if (!nr || nr > INODES)
                return NULL;
        inode = Inode2 + nr;
        get_inode_common(nr, inode->i_mode);
        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_common(int block, smallint *corrected)
{
        if (!block)
                return 0;
        if (zone_count[block]) {
                printf("Already used block is reused in file '%s'. ",
                                current_name);
                if (ask("Clear", 1)) {
                        block = 0;
                        *corrected = 1;
                        return -1; /* "please zero out *znr" */
                }
        }
        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;
}

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

        block = check_zone_nr(znr, corrected);
        block = add_zone_common(block, corrected);
        if (block == -1) {
                *znr = 0;
                block = 0;
        }
        return block;
}

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

        block = check_zone_nr2(znr, corrected);
        block = add_zone_common(block, corrected);
        if (block == -1) {
                *znr = 0;
                block = 0;
        }
        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 (OPT_list) {
                if (OPT_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 (OPT_list) {
                if (OPT_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];

        xlseek(dev_fd, BLOCK_SIZE * i, SEEK_SET);
        return (BLOCK_SIZE != full_read(dev_fd, buffer, BLOCK_SIZE));
}

static void check_counts(void)
{
        int i;

        for (i = 1; i <= INODES; i++) {
                if (OPT_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 (OPT_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) MAIN_EXTERNALLY_VISIBLE;
int fsck_minix_main(int argc UNUSED_PARAM, char **argv)
{
        struct termios tmp;
        int retcode = 0;

        xfunc_error_retval = 8;

        INIT_G();

        opt_complementary = "=1:ar"; /* one argument; -a assumes -r */
        getopt32(argv, OPTION_STR);
        argv += optind;
        device_name = argv[0];

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

        /*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) && !OPT_force
        ) {
                if (OPT_repair)
                        printf("%s is clean, check is skipped\n", device_name);
                return 0;
        } else if (OPT_force)
                printf("Forcing filesystem check on %s\n", device_name);
        else if (OPT_repair)
                printf("Filesystem on %s is dirty, needs checking\n",
                           device_name);

        read_tables();

        if (OPT_manual) {
                tcgetattr(0, &sv_termios);
                tmp = sv_termios;
                tmp.c_lflag &= ~(ICANON | ECHO);
                tcsetattr_stdin_TCSANOW(&tmp);
                termios_set = 1;
        }

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

        if (OPT_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 (OPT_repair)
                write_superblock();

        if (OPT_manual)
                tcsetattr_stdin_TCSANOW(&sv_termios);

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