source: MondoRescue/branches/3.3/mindi-busybox/e2fsprogs/fsck.c@ 3625

/* vi: set sw=4 ts=4: */
/*
 * fsck --- A generic, parallelizing front-end for the fsck program.
 * It will automatically try to run fsck programs in parallel if the
 * devices are on separate spindles.  It is based on the same ideas as
 * the generic front end for fsck by David Engel and Fred van Kempen,
 * but it has been completely rewritten from scratch to support
 * parallel execution.
 *
 * Written by Theodore Ts'o, <tytso@mit.edu>
 *
 * Miquel van Smoorenburg (miquels@drinkel.ow.org) 20-Oct-1994:
 *   o Changed -t fstype to behave like with mount when -A (all file
 *     systems) or -M (like mount) is specified.
 *   o fsck looks if it can find the fsck.type program to decide
 *     if it should ignore the fs type. This way more fsck programs
 *     can be added without changing this front-end.
 *   o -R flag skip root file system.
 *
 * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
 *      2001, 2002, 2003, 2004, 2005 by  Theodore Ts'o.
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

/* All filesystem specific hooks have been removed.
 * If filesystem cannot be determined, we will execute
 * "fsck.auto". Currently this also happens if you specify
 * UUID=xxx or LABEL=xxx as an object to check.
 * Detection code for that is also probably has to be in fsck.auto.
 *
 * In other words, this is _really_ is just a driver program which
 * spawns actual fsck.something for each filesystem to check.
 * It doesn't guess filesystem types from on-disk format.
 */
//config:config FSCK
//config:   bool "fsck"
//config:   default y
//config:   help
//config:     fsck is used to check and optionally repair one or more filesystems.
//config:     In actuality, fsck is simply a front-end for the various file system
//config:     checkers (fsck.fstype) available under Linux.

//applet:IF_FSCK(APPLET(fsck, BB_DIR_SBIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_FSCK) += fsck.o

//usage:#define fsck_trivial_usage
//usage:       "[-ANPRTV] [-t FSTYPE] [FS_OPTS] [BLOCKDEV]..."
//usage:#define fsck_full_usage "\n\n"
//usage:       "Check and repair filesystems\n"
//usage:     "\n    -A  Walk /etc/fstab and check all filesystems"
//usage:     "\n    -N  Don't execute, just show what would be done"
//usage:     "\n    -P  With -A, check filesystems in parallel"
//usage:     "\n    -R  With -A, skip the root filesystem"
//usage:     "\n    -T  Don't show title on startup"
//usage:     "\n    -V  Verbose"
//DO_PROGRESS_INDICATOR is off:
////usage:     "\n  -C FD   Write status information to specified file descriptor"
//usage:     "\n    -t TYPE List of filesystem types to check"

#include "libbb.h"
#include "common_bufsiz.h"

/* "progress indicator" code is somewhat buggy and ext[23] specific.
 * We should be filesystem agnostic. IOW: there should be a well-defined
 * API for fsck.something, NOT ad-hoc hacks in generic fsck. */
#define DO_PROGRESS_INDICATOR 0

/* fsck 1.41.4 (27-Jan-2009) manpage says:
 * 0   - No errors
 * 1   - File system errors corrected
 * 2   - System should be rebooted
 * 4   - File system errors left uncorrected
 * 8   - Operational error
 * 16  - Usage or syntax error
 * 32  - Fsck canceled by user request
 * 128 - Shared library error
 */
#define EXIT_OK          0
#define EXIT_NONDESTRUCT 1
#define EXIT_DESTRUCT    2
#define EXIT_UNCORRECTED 4
#define EXIT_ERROR       8
#define EXIT_USAGE       16
#define FSCK_CANCELED    32     /* Aborted with a signal or ^C */

/*
 * Internal structure for mount table entries.
 */
struct fs_info {
    struct fs_info *next;
    char    *device;
    char    *mountpt;
    char    *type;
    char    *opts;
    int passno;
    int flags;
};

#define FLAG_DONE 1
#define FLAG_PROGRESS 2
/*
 * Structure to allow exit codes to be stored
 */
struct fsck_instance {
    struct fsck_instance *next;
    int pid;
    int flags;
#if DO_PROGRESS_INDICATOR
    time_t  start_time;
#endif
    char    *prog;
    char    *device;
    char    *base_device; /* /dev/hda for /dev/hdaN etc */
};

static const char ignored_types[] ALIGN1 =
    "ignore\0"
    "iso9660\0"
    "nfs\0"
    "proc\0"
    "sw\0"
    "swap\0"
    "tmpfs\0"
    "devpts\0";

#if 0
static const char really_wanted[] ALIGN1 =
    "minix\0"
    "ext2\0"
    "ext3\0"
    "jfs\0"
    "reiserfs\0"
    "xiafs\0"
    "xfs\0";
#endif

#define BASE_MD "/dev/md"

struct globals {
    char **args;
    int num_args;
    int verbose;

#define FS_TYPE_FLAG_NORMAL 0
#define FS_TYPE_FLAG_OPT    1
#define FS_TYPE_FLAG_NEGOPT 2
    char **fs_type_list;
    uint8_t *fs_type_flag;
    smallint fs_type_negated;

    smallint noexecute;
    smallint serialize;
    smallint skip_root;
    /* smallint like_mount; */
    smallint parallel_root;
    smallint force_all_parallel;
    smallint kill_sent;

#if DO_PROGRESS_INDICATOR
    smallint progress;
    int progress_fd;
#endif

    int num_running;
    int max_running;
    char *fstype;
    struct fs_info *filesys_info;
    struct fs_info *filesys_last;
    struct fsck_instance *instance_list;
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() do { \
    setup_common_bufsiz(); \
    BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
} while (0)

/*
 * Return the "base device" given a particular device; this is used to
 * assure that we only fsck one partition on a particular drive at any
 * one time.  Otherwise, the disk heads will be seeking all over the
 * place.  If the base device cannot be determined, return NULL.
 *
 * The base_device() function returns an allocated string which must
 * be freed.
 */
#if ENABLE_FEATURE_DEVFS
/*
 * Required for the uber-silly devfs /dev/ide/host1/bus2/target3/lun3
 * pathames.
 */
static const char *const devfs_hier[] = {
    "host", "bus", "target", "lun", NULL
};
#endif

static char *base_device(const char *device)
{
    char *str, *cp;
#if ENABLE_FEATURE_DEVFS
    const char *const *hier;
    const char *disk;
    int len;
#endif
    str = xstrdup(device);

    /* Skip over "/dev/"; if it's not present, give up */
    cp = skip_dev_pfx(str);
    if (cp == str)
        goto errout;

    /*
     * For md devices, we treat them all as if they were all
     * on one disk, since we don't know how to parallelize them.
     */
    if (cp[0] == 'm' && cp[1] == 'd') {
        cp[2] = 0;
        return str;
    }

    /* Handle DAC 960 devices */
    if (is_prefixed_with(cp, "rd/")) {
        cp += 3;
        if (cp[0] != 'c' || !isdigit(cp[1])
         || cp[2] != 'd' || !isdigit(cp[3]))
            goto errout;
        cp[4] = 0;
        return str;
    }

    /* Now let's handle /dev/hd* and /dev/sd* devices.... */
    if ((cp[0] == 'h' || cp[0] == 's') && cp[1] == 'd') {
        cp += 2;
        /* If there's a single number after /dev/hd, skip it */
        if (isdigit(*cp))
            cp++;
        /* What follows must be an alpha char, or give up */
        if (!isalpha(*cp))
            goto errout;
        cp[1] = 0;
        return str;
    }

#if ENABLE_FEATURE_DEVFS
    /* Now let's handle devfs (ugh) names */
    len = 0;
    if (is_prefixed_with(cp, "ide/"))
        len = 4;
    if (is_prefixed_with(cp, "scsi/"))
        len = 5;
    if (len) {
        cp += len;
        /*
         * Now we proceed down the expected devfs hierarchy.
         * i.e., .../host1/bus2/target3/lun4/...
         * If we don't find the expected token, followed by
         * some number of digits at each level, abort.
         */
        for (hier = devfs_hier; *hier; hier++) {
            cp = is_prefixed_with(cp, *hier);
            if (!cp)
                goto errout;
            while (*cp != '/' && *cp != '\0') {
                if (!isdigit(*cp))
                    goto errout;
                cp++;
            }
//FIXME: what if *cp = '\0' now? cp++ moves past it!!!
            cp++;
        }
        cp[-1] = '\0';
        return str;
    }

    /* Now handle devfs /dev/disc or /dev/disk names */
    disk = NULL;
    if (is_prefixed_with(cp, "discs/"))
        disk = "disc";
    else if (is_prefixed_with(cp, "disks/"))
        disk = "disk";
    if (disk) {
        cp += 6;
        cp = is_prefixed_with(cp, disk);
        if (!cp)
            goto errout;
        while (*cp != '/' && *cp != '\0') {
            if (!isdigit(*cp))
                goto errout;
            cp++;
        }
        *cp = '\0';
        return str;
    }
#endif
 errout:
    free(str);
    return NULL;
}

static void free_instance(struct fsck_instance *p)
{
    free(p->prog);
    free(p->device);
    free(p->base_device);
    free(p);
}

static struct fs_info *create_fs_device(const char *device, const char *mntpnt,
                    const char *type, const char *opts,
                    int passno)
{
    struct fs_info *fs;

    fs = xzalloc(sizeof(*fs));
    fs->device = xstrdup(device);
    fs->mountpt = xstrdup(mntpnt);
    if (strchr(type, ','))
        type = (char *)"auto";
    fs->type = xstrdup(type);
    fs->opts = xstrdup(opts ? opts : "");
    fs->passno = passno < 0 ? 1 : passno;
    /*fs->flags = 0; */
    /*fs->next = NULL; */

    if (!G.filesys_info)
        G.filesys_info = fs;
    else
        G.filesys_last->next = fs;
    G.filesys_last = fs;

    return fs;
}

/* Load the filesystem database from /etc/fstab */
static void load_fs_info(const char *filename)
{
    FILE *fstab;
    struct mntent mte;
    char buf[1024];

    fstab = setmntent(filename, "r");
    if (!fstab) {
        bb_perror_msg("can't read '%s'", filename);
        return;
    }

    // Loop through entries
    while (getmntent_r(fstab, &mte, buf, sizeof(buf))) {
        //bb_error_msg("CREATE[%s][%s][%s][%s][%d]", mte.mnt_fsname, mte.mnt_dir,
        //  mte.mnt_type, mte.mnt_opts,
        //  mte.mnt_passno);
        create_fs_device(mte.mnt_fsname, mte.mnt_dir,
            mte.mnt_type, mte.mnt_opts,
            mte.mnt_passno);
    }
    endmntent(fstab);
}

/* Lookup filesys in /etc/fstab and return the corresponding entry. */
static struct fs_info *lookup(char *filesys)
{
    struct fs_info *fs;

    for (fs = G.filesys_info; fs; fs = fs->next) {
        if (strcmp(filesys, fs->device) == 0
         || (fs->mountpt && strcmp(filesys, fs->mountpt) == 0)
        )
            break;
    }

    return fs;
}

#if DO_PROGRESS_INDICATOR
static int progress_active(void)
{
    struct fsck_instance *inst;

    for (inst = G.instance_list; inst; inst = inst->next) {
        if (inst->flags & FLAG_DONE)
            continue;
        if (inst->flags & FLAG_PROGRESS)
            return 1;
    }
    return 0;
}
#endif


/*
 * Send a signal to all outstanding fsck child processes
 */
static void kill_all_if_got_signal(void)
{
    struct fsck_instance *inst;

    if (!bb_got_signal || G.kill_sent)
        return;

    for (inst = G.instance_list; inst; inst = inst->next) {
        if (inst->flags & FLAG_DONE)
            continue;
        kill(inst->pid, SIGTERM);
    }
    G.kill_sent = 1;
}

/*
 * Wait for one child process to exit; when it does, unlink it from
 * the list of executing child processes, free, and return its exit status.
 * If there is no exited child, return -1.
 */
static int wait_one(int flags)
{
    int status;
    int sig;
    struct fsck_instance *inst, *prev;
    pid_t pid;

    if (!G.instance_list)
        return -1;
    /* if (G.noexecute) { already returned -1; } */

    while (1) {
        pid = waitpid(-1, &status, flags);
        kill_all_if_got_signal();
        if (pid == 0) /* flags == WNOHANG and no children exited */
            return -1;
        if (pid < 0) {
            if (errno == EINTR)
                continue;
            if (errno == ECHILD) { /* paranoia */
                bb_error_msg("wait: no more children");
                return -1;
            }
            bb_perror_msg("wait");
            continue;
        }
        prev = NULL;
        inst = G.instance_list;
        do {
            if (inst->pid == pid)
                goto child_died;
            prev = inst;
            inst = inst->next;
        } while (inst);
    }
 child_died:

    status = WEXITSTATUS(status);
    if (WIFSIGNALED(status)) {
        sig = WTERMSIG(status);
        status = EXIT_UNCORRECTED;
        if (sig != SIGINT) {
            printf("Warning: %s %s terminated "
                "by signal %d\n",
                inst->prog, inst->device, sig);
            status = EXIT_ERROR;
        }
    }

#if DO_PROGRESS_INDICATOR
    if (progress && (inst->flags & FLAG_PROGRESS) && !progress_active()) {
        struct fsck_instance *inst2;
        for (inst2 = G.instance_list; inst2; inst2 = inst2->next) {
            if (inst2->flags & FLAG_DONE)
                continue;
            if (strcmp(inst2->type, "ext2") != 0
             && strcmp(inst2->type, "ext3") != 0
            ) {
                continue;
            }
            /* ext[23], we will send USR1
             * (request to start displaying progress bar)
             *
             * If we've just started the fsck, wait a tiny
             * bit before sending the kill, to give it
             * time to set up the signal handler
             */
            if (inst2->start_time >= time(NULL) - 1)
                sleep(1);
            kill(inst2->pid, SIGUSR1);
            inst2->flags |= FLAG_PROGRESS;
            break;
        }
    }
#endif

    if (prev)
        prev->next = inst->next;
    else
        G.instance_list = inst->next;
    if (G.verbose > 1)
        printf("Finished with %s (exit status %d)\n",
            inst->device, status);
    G.num_running--;
    free_instance(inst);

    return status;
}

/*
 * Wait until all executing child processes have exited; return the
 * logical OR of all of their exit code values.
 */
#define FLAG_WAIT_ALL           0
#define FLAG_WAIT_ATLEAST_ONE   WNOHANG
static int wait_many(int flags)
{
    int exit_status;
    int global_status = 0;
    int wait_flags = 0;

    while ((exit_status = wait_one(wait_flags)) != -1) {
        global_status |= exit_status;
        wait_flags |= flags;
    }
    return global_status;
}

/*
 * Execute a particular fsck program, and link it into the list of
 * child processes we are waiting for.
 */
static void execute(const char *type, const char *device,
        const char *mntpt /*, int interactive */)
{
    int i;
    struct fsck_instance *inst;
    pid_t pid;

    G.args[0] = xasprintf("fsck.%s", type);

#if DO_PROGRESS_INDICATOR
    if (progress && !progress_active()) {
        if (strcmp(type, "ext2") == 0
         || strcmp(type, "ext3") == 0
        ) {
            G.args[XXX] = xasprintf("-C%d", progress_fd); /* 1 */
            inst->flags |= FLAG_PROGRESS;
        }
    }
#endif

    G.args[G.num_args - 2] = (char*)device;
    /* G.args[G.num_args - 1] = NULL; - already is */

    if (G.verbose || G.noexecute) {
        printf("[%s (%d) -- %s]", G.args[0], G.num_running,
                    mntpt ? mntpt : device);
        for (i = 0; G.args[i]; i++)
            printf(" %s", G.args[i]);
        bb_putchar('\n');
    }

    /* Fork and execute the correct program. */
    pid = -1;
    if (!G.noexecute) {
        pid = spawn(G.args);
        if (pid < 0)
            bb_simple_perror_msg(G.args[0]);
    }

#if DO_PROGRESS_INDICATOR
    free(G.args[XXX]);
#endif

    /* No child, so don't record an instance */
    if (pid <= 0) {
        free(G.args[0]);
        return;
    }

    inst = xzalloc(sizeof(*inst));
    inst->pid = pid;
    inst->prog = G.args[0];
    inst->device = xstrdup(device);
    inst->base_device = base_device(device);
#if DO_PROGRESS_INDICATOR
    inst->start_time = time(NULL);
#endif

    /* Add to the list of running fsck's.
     * (was adding to the end, but adding to the front is simpler...) */
    inst->next = G.instance_list;
    G.instance_list = inst;
}

/*
 * Run the fsck program on a particular device
 *
 * If the type is specified using -t, and it isn't prefixed with "no"
 * (as in "noext2") and only one filesystem type is specified, then
 * use that type regardless of what is specified in /etc/fstab.
 *
 * If the type isn't specified by the user, then use either the type
 * specified in /etc/fstab, or "auto".
 */
static void fsck_device(struct fs_info *fs /*, int interactive */)
{
    const char *type;

    if (strcmp(fs->type, "auto") != 0) {
        type = fs->type;
        if (G.verbose > 2)
            printf("using filesystem type '%s' %s\n",
                    type, "from fstab");
    } else if (G.fstype
     && (G.fstype[0] != 'n' || G.fstype[1] != 'o') /* != "no" */
     && !is_prefixed_with(G.fstype, "opts=")
     && !is_prefixed_with(G.fstype, "loop")
     && !strchr(G.fstype, ',')
    ) {
        type = G.fstype;
        if (G.verbose > 2)
            printf("using filesystem type '%s' %s\n",
                    type, "from -t");
    } else {
        type = "auto";
        if (G.verbose > 2)
            printf("using filesystem type '%s' %s\n",
                    type, "(default)");
    }

    G.num_running++;
    execute(type, fs->device, fs->mountpt /*, interactive */);
}

/*
 * Returns TRUE if a partition on the same disk is already being
 * checked.
 */
static int device_already_active(char *device)
{
    struct fsck_instance *inst;
    char *base;

    if (G.force_all_parallel)
        return 0;

#ifdef BASE_MD
    /* Don't check a soft raid disk with any other disk */
    if (G.instance_list
     && (is_prefixed_with(G.instance_list->device, BASE_MD)
         || is_prefixed_with(device, BASE_MD))
    ) {
        return 1;
    }
#endif

    base = base_device(device);
    /*
     * If we don't know the base device, assume that the device is
     * already active if there are any fsck instances running.
     */
    if (!base)
        return (G.instance_list != NULL);

    for (inst = G.instance_list; inst; inst = inst->next) {
        if (!inst->base_device || !strcmp(base, inst->base_device)) {
            free(base);
            return 1;
        }
    }

    free(base);
    return 0;
}

/*
 * This function returns true if a particular option appears in a
 * comma-delimited options list
 */
static int opt_in_list(char *opt, char *optlist)
{
    char *s;
    int len;

    if (!optlist)
        return 0;

    len = strlen(opt);
    s = optlist - 1;
    while (1) {
        s = strstr(s + 1, opt);
        if (!s)
            return 0;
        /* neither "opt.." nor "xxx,opt.."? */
        if (s != optlist && s[-1] != ',')
            continue;
        /* neither "..opt" nor "..opt,xxx"? */
        if (s[len] != '\0' && s[len] != ',')
            continue;
        return 1;
    }
}

/* See if the filesystem matches the criteria given by the -t option */
static int fs_match(struct fs_info *fs)
{
    int n, ret, checked_type;
    char *cp;

    if (!G.fs_type_list)
        return 1;

    ret = 0;
    checked_type = 0;
    n = 0;
    while (1) {
        cp = G.fs_type_list[n];
        if (!cp)
            break;
        switch (G.fs_type_flag[n]) {
        case FS_TYPE_FLAG_NORMAL:
            checked_type++;
            if (strcmp(cp, fs->type) == 0)
                ret = 1;
            break;
        case FS_TYPE_FLAG_NEGOPT:
            if (opt_in_list(cp, fs->opts))
                return 0;
            break;
        case FS_TYPE_FLAG_OPT:
            if (!opt_in_list(cp, fs->opts))
                return 0;
            break;
        }
        n++;
    }
    if (checked_type == 0)
        return 1;

    return (G.fs_type_negated ? !ret : ret);
}

/* Check if we should ignore this filesystem. */
static int ignore(struct fs_info *fs)
{
    /*
     * If the pass number is 0, ignore it.
     */
    if (fs->passno == 0)
        return 1;

    /*
     * If a specific fstype is specified, and it doesn't match,
     * ignore it.
     */
    if (!fs_match(fs))
        return 1;

    /* Are we ignoring this type? */
    if (index_in_strings(ignored_types, fs->type) >= 0)
        return 1;

    /* We can and want to check this file system type. */
    return 0;
}

/* Check all file systems, using the /etc/fstab table. */
static int check_all(void)
{
    struct fs_info *fs;
    int status = EXIT_OK;
    smallint not_done_yet;
    smallint pass_done;
    int passno;

    if (G.verbose)
        puts("Checking all filesystems");

    /*
     * Do an initial scan over the filesystem; mark filesystems
     * which should be ignored as done, and resolve any "auto"
     * filesystem types (done as a side-effect of calling ignore()).
     */
    for (fs = G.filesys_info; fs; fs = fs->next)
        if (ignore(fs))
            fs->flags |= FLAG_DONE;

    /*
     * Find and check the root filesystem.
     */
    if (!G.parallel_root) {
        for (fs = G.filesys_info; fs; fs = fs->next) {
            if (LONE_CHAR(fs->mountpt, '/')) {
                if (!G.skip_root && !ignore(fs)) {
                    fsck_device(fs /*, 1*/);
                    status |= wait_many(FLAG_WAIT_ALL);
                    if (status > EXIT_NONDESTRUCT)
                        return status;
                }
                fs->flags |= FLAG_DONE;
                break;
            }
        }
    }
    /*
     * This is for the bone-headed user who has root
     * filesystem listed twice.
     * "Skip root" will skip _all_ root entries.
     */
    if (G.skip_root)
        for (fs = G.filesys_info; fs; fs = fs->next)
            if (LONE_CHAR(fs->mountpt, '/'))
                fs->flags |= FLAG_DONE;

    not_done_yet = 1;
    passno = 1;
    while (not_done_yet) {
        not_done_yet = 0;
        pass_done = 1;

        for (fs = G.filesys_info; fs; fs = fs->next) {
            if (bb_got_signal)
                break;
            if (fs->flags & FLAG_DONE)
                continue;
            /*
             * If the filesystem's pass number is higher
             * than the current pass number, then we didn't
             * do it yet.
             */
            if (fs->passno > passno) {
                not_done_yet = 1;
                continue;
            }
            /*
             * If a filesystem on a particular device has
             * already been spawned, then we need to defer
             * this to another pass.
             */
            if (device_already_active(fs->device)) {
                pass_done = 0;
                continue;
            }
            /*
             * Spawn off the fsck process
             */
            fsck_device(fs /*, G.serialize*/);
            fs->flags |= FLAG_DONE;

            /*
             * Only do one filesystem at a time, or if we
             * have a limit on the number of fsck's extant
             * at one time, apply that limit.
             */
            if (G.serialize
             || (G.num_running >= G.max_running)
            ) {
                pass_done = 0;
                break;
            }
        }
        if (bb_got_signal)
            break;
        if (G.verbose > 1)
            printf("--waiting-- (pass %d)\n", passno);
        status |= wait_many(pass_done ? FLAG_WAIT_ALL :
                FLAG_WAIT_ATLEAST_ONE);
        if (pass_done) {
            if (G.verbose > 1)
                puts("----------------------------------");
            passno++;
        } else
            not_done_yet = 1;
    }
    kill_all_if_got_signal();
    status |= wait_many(FLAG_WAIT_ATLEAST_ONE);
    return status;
}

/*
 * Deal with the fsck -t argument.
 * Huh, for mount "-t novfat,nfs" means "neither vfat nor nfs"!
 * Why here we require "-t novfat,nonfs" ??
 */
static void compile_fs_type(char *fs_type)
{
    char *s;
    int num = 2;
    smallint negate;

    s = fs_type;
    while ((s = strchr(s, ','))) {
        num++;
        s++;
    }

    G.fs_type_list = xzalloc(num * sizeof(G.fs_type_list[0]));
    G.fs_type_flag = xzalloc(num * sizeof(G.fs_type_flag[0]));
    G.fs_type_negated = -1; /* not yet known is it negated or not */

    num = 0;
    s = fs_type;
    while (1) {
        char *comma;

        negate = 0;
        if (s[0] == 'n' && s[1] == 'o') { /* "no.." */
            s += 2;
            negate = 1;
        } else if (s[0] == '!') {
            s++;
            negate = 1;
        }

        if (strcmp(s, "loop") == 0)
            /* loop is really short-hand for opts=loop */
            goto loop_special_case;
        if (is_prefixed_with(s, "opts=")) {
            s += 5;
 loop_special_case:
            G.fs_type_flag[num] = negate ? FS_TYPE_FLAG_NEGOPT : FS_TYPE_FLAG_OPT;
        } else {
            if (G.fs_type_negated == -1)
                G.fs_type_negated = negate;
            if (G.fs_type_negated != negate)
                bb_error_msg_and_die(
"either all or none of the filesystem types passed to -t must be prefixed "
"with 'no' or '!'");
        }
        comma = strchrnul(s, ',');
        G.fs_type_list[num++] = xstrndup(s, comma-s);
        if (*comma == '\0')
            break;
        s = comma + 1;
    }
}

static char **new_args(void)
{
    G.args = xrealloc_vector(G.args, 2, G.num_args);
    return &G.args[G.num_args++];
}

int fsck_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fsck_main(int argc UNUSED_PARAM, char **argv)
{
    int i, status;
    /*int interactive;*/
    struct fs_info *fs;
    const char *fstab;
    char *tmp;
    char **devices;
    int num_devices;
    smallint opts_for_fsck;
    smallint doall;
    smallint notitle;

    INIT_G();

    /* we want wait() to be interruptible */
    signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
    signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo);

    setbuf(stdout, NULL);

    opts_for_fsck = doall = notitle = 0;
    devices = NULL;
    num_devices = 0;
    new_args(); /* G.args[0] = NULL, will be replaced by fsck.<type> */
    /* G.instance_list = NULL; - in bss, so already zeroed */

    while (*++argv) {
        int j;
        int optpos;
        char *options;
        char *arg = *argv;

        /* "/dev/blk" or "/path" or "UUID=xxx" or "LABEL=xxx" */
        if ((arg[0] == '/' && !opts_for_fsck) || strchr(arg, '=')) {
// FIXME: must check that arg is a blkdev, or resolve
// "/path", "UUID=xxx" or "LABEL=xxx" into block device name
// ("UUID=xxx"/"LABEL=xxx" can probably shifted to fsck.auto duties)
            devices = xrealloc_vector(devices, 2, num_devices);
            devices[num_devices++] = arg;
            continue;
        }

        if (arg[0] != '-' || opts_for_fsck) {
            *new_args() = arg;
            continue;
        }

        if (LONE_CHAR(arg + 1, '-')) { /* "--" ? */
            opts_for_fsck = 1;
            continue;
        }

        optpos = 0;
        options = NULL;
        for (j = 1; arg[j]; j++) {
            switch (arg[j]) {
            case 'A':
                doall = 1;
                break;
#if DO_PROGRESS_INDICATOR
            case 'C':
                progress = 1;
                if (arg[++j]) { /* -Cn */
                    progress_fd = xatoi_positive(&arg[j]);
                    goto next_arg;
                }
                /* -C n */
                if (!*++argv)
                    bb_show_usage();
                progress_fd = xatoi_positive(*argv);
                goto next_arg;
#endif
            case 'V':
                G.verbose++;
                break;
            case 'N':
                G.noexecute = 1;
                break;
            case 'R':
                G.skip_root = 1;
                break;
            case 'T':
                notitle = 1;
                break;
/*          case 'M':
                like_mount = 1;
                break; */
            case 'P':
                G.parallel_root = 1;
                break;
            case 's':
                G.serialize = 1;
                break;
            case 't':
                if (G.fstype)
                    bb_show_usage();
                if (arg[++j])
                    tmp = &arg[j];
                else if (*++argv)
                    tmp = *argv;
                else
                    bb_show_usage();
                G.fstype = xstrdup(tmp);
                compile_fs_type(G.fstype);
                goto next_arg;
            case '?':
                bb_show_usage();
                break;
            default:
                optpos++;
                /* one extra for '\0' */
                options = xrealloc(options, optpos + 2);
                options[optpos] = arg[j];
                break;
            }
        }
 next_arg:
        if (optpos) {
            options[0] = '-';
            options[optpos + 1] = '\0';
            *new_args() = options;
        }
    }
    if (getenv("FSCK_FORCE_ALL_PARALLEL"))
        G.force_all_parallel = 1;
    tmp = getenv("FSCK_MAX_INST");
    G.max_running = INT_MAX;
    if (tmp)
        G.max_running = xatoi(tmp);
    new_args(); /* G.args[G.num_args - 2] will be replaced by <device> */
    new_args(); /* G.args[G.num_args - 1] is the last, NULL element */

    if (!notitle)
        puts("fsck (busybox "BB_VER", "BB_BT")");

    /* Even plain "fsck /dev/hda1" needs fstab to get fs type,
     * so we are scanning it anyway */
    fstab = getenv("FSTAB_FILE");
    if (!fstab)
        fstab = "/etc/fstab";
    load_fs_info(fstab);

    /*interactive = (num_devices == 1) | G.serialize;*/

    if (num_devices == 0)
        /*interactive =*/ G.serialize = doall = 1;
    if (doall)
        return check_all();

    status = 0;
    for (i = 0; i < num_devices; i++) {
        if (bb_got_signal) {
            kill_all_if_got_signal();
            break;
        }

        fs = lookup(devices[i]);
        if (!fs)
            fs = create_fs_device(devices[i], "", "auto", NULL, -1);
        fsck_device(fs /*, interactive */);

        if (G.serialize
         || (G.num_running >= G.max_running)
        ) {
            int exit_status = wait_one(0);
            if (exit_status >= 0)
                status |= exit_status;
            if (G.verbose > 1)
                puts("----------------------------------");
        }
    }
    status |= wait_many(FLAG_WAIT_ALL);
    return status;
}