/* 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;
}