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

/* vi: set sw=4 ts=4: */
/*
 * Mini mount implementation for busybox
 *
 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 * Copyright (C) 2005-2006 by Rob Landley <rob@landley.net>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

/* Design notes: There is no spec for mount.  Remind me to write one.

   mount_main() calls singlemount() which calls mount_it_now().

   mount_main() can loop through /etc/fstab for mount -a
   singlemount() can loop through /etc/filesystems for fstype detection.
   mount_it_now() does the actual mount.
*/

#include "libbb.h"
#include <mntent.h>

/* Needed for nfs support only... */
#include <syslog.h>
#include <sys/utsname.h>
#undef TRUE
#undef FALSE
#include <rpc/rpc.h>
#include <rpc/pmap_prot.h>
#include <rpc/pmap_clnt.h>


#if defined(__dietlibc__)
/* 16.12.2006, Sampo Kellomaki (sampo@iki.fi)
 * dietlibc-0.30 does not have implementation of getmntent_r() */
/* OTOH: why we use getmntent_r instead of getmntent? TODO... */
struct mntent *getmntent_r(FILE* stream, struct mntent* result, char* buffer, int bufsize)
{
    /* *** XXX FIXME WARNING: This hack is NOT thread safe. --Sampo */
    struct mntent* ment = getmntent(stream);
    memcpy(result, ment, sizeof(struct mntent));
    return result;
}
#endif


// Not real flags, but we want to be able to check for this.
enum {
    MOUNT_USERS  = (1<<28)*ENABLE_DESKTOP,
    MOUNT_NOAUTO = (1<<29),
    MOUNT_SWAP   = (1<<30),
};
// TODO: more "user" flag compatibility.
// "user" option (from mount manpage):
// Only the user that mounted a filesystem can unmount it again.
// If any user should be able to unmount, then use users instead of user
// in the fstab line.  The owner option is similar to the user option,
// with the restriction that the user must be the owner of the special file.
// This may be useful e.g. for /dev/fd if a login script makes
// the console user owner of this device.

/* Standard mount options (from -o options or --options), with corresponding
 * flags */

struct {
    const char *name;
    long flags;
} static mount_options[] = {
    // MS_FLAGS set a bit.  ~MS_FLAGS disable that bit.  0 flags are NOPs.

    USE_FEATURE_MOUNT_LOOP(
        {"loop", 0},
    )

    USE_FEATURE_MOUNT_FSTAB(
        {"defaults", 0},
        /* {"quiet", 0}, - do not filter out, vfat wants to see it */
        {"noauto", MOUNT_NOAUTO},
        {"sw", MOUNT_SWAP},
        {"swap", MOUNT_SWAP},
        USE_DESKTOP({"user",  MOUNT_USERS},)
        USE_DESKTOP({"users", MOUNT_USERS},)
    )

    USE_FEATURE_MOUNT_FLAGS(
        // vfs flags
        {"nosuid", MS_NOSUID},
        {"suid", ~MS_NOSUID},
        {"dev", ~MS_NODEV},
        {"nodev", MS_NODEV},
        {"exec", ~MS_NOEXEC},
        {"noexec", MS_NOEXEC},
        {"sync", MS_SYNCHRONOUS},
        {"async", ~MS_SYNCHRONOUS},
        {"atime", ~MS_NOATIME},
        {"noatime", MS_NOATIME},
        {"diratime", ~MS_NODIRATIME},
        {"nodiratime", MS_NODIRATIME},
        {"loud", ~MS_SILENT},

        // action flags

        {"bind", MS_BIND},
        {"move", MS_MOVE},
        {"shared", MS_SHARED},
        {"slave", MS_SLAVE},
        {"private", MS_PRIVATE},
        {"unbindable", MS_UNBINDABLE},
        {"rshared", MS_SHARED|MS_RECURSIVE},
        {"rslave", MS_SLAVE|MS_RECURSIVE},
        {"rprivate", MS_SLAVE|MS_RECURSIVE},
        {"runbindable", MS_UNBINDABLE|MS_RECURSIVE},
    )

    // Always understood.

    {"ro", MS_RDONLY},        // vfs flag
    {"rw", ~MS_RDONLY},       // vfs flag
    {"remount", MS_REMOUNT},  // action flag
};


/* Append mount options to string */
static void append_mount_options(char **oldopts, const char *newopts)
{
    if (*oldopts && **oldopts) {
        /* do not insert options which are already there */
        while (newopts[0]) {
            char *p;
            int len = strlen(newopts);
            p = strchr(newopts, ',');
            if (p) len = p - newopts;
            p = *oldopts;
            while (1) {
                if (!strncmp(p, newopts, len)
                 && (p[len]==',' || p[len]==0))
                    goto skip;
                p = strchr(p,',');
                if (!p) break;
                p++;
            }
            p = xasprintf("%s,%.*s", *oldopts, len, newopts);
            free(*oldopts);
            *oldopts = p;
skip:
            newopts += len;
            while (newopts[0] == ',') newopts++;
        }
    } else {
        if (ENABLE_FEATURE_CLEAN_UP) free(*oldopts);
        *oldopts = xstrdup(newopts);
    }
}

/* Use the mount_options list to parse options into flags.
 * Also return list of unrecognized options if unrecognized!=NULL */
static int parse_mount_options(char *options, char **unrecognized)
{
    int flags = MS_SILENT;

    // Loop through options
    for (;;) {
        int i;
        char *comma = strchr(options, ',');

        if (comma) *comma = 0;

        // Find this option in mount_options
        for (i = 0; i < ARRAY_SIZE(mount_options); i++) {
            if (!strcasecmp(mount_options[i].name, options)) {
                long fl = mount_options[i].flags;
                if (fl < 0) flags &= fl;
                else flags |= fl;
                break;
            }
        }
        // If unrecognized not NULL, append unrecognized mount options */
        if (unrecognized && i == ARRAY_SIZE(mount_options)) {
            // Add it to strflags, to pass on to kernel
            i = *unrecognized ? strlen(*unrecognized) : 0;
            *unrecognized = xrealloc(*unrecognized, i+strlen(options)+2);

            // Comma separated if it's not the first one
            if (i) (*unrecognized)[i++] = ',';
            strcpy((*unrecognized)+i, options);
        }

        // Advance to next option, or finish
        if (comma) {
            *comma = ',';
            options = ++comma;
        } else break;
    }

    return flags;
}

// Return a list of all block device backed filesystems

static llist_t *get_block_backed_filesystems(void)
{
    static const char filesystems[2][sizeof("/proc/filesystems")] = {
        "/etc/filesystems",
        "/proc/filesystems",
    };
    char *fs, *buf;
    llist_t *list = 0;
    int i;
    FILE *f;

    for (i = 0; i < 2; i++) {
        f = fopen(filesystems[i], "r");
        if (!f) continue;

        while ((buf = xmalloc_getline(f)) != 0) {
            if (!strncmp(buf, "nodev", 5) && isspace(buf[5]))
                continue;
            fs = skip_whitespace(buf);
            if (*fs=='#' || *fs=='*' || !*fs) continue;

            llist_add_to_end(&list, xstrdup(fs));
            free(buf);
        }
        if (ENABLE_FEATURE_CLEAN_UP) fclose(f);
    }

    return list;
}

llist_t *fslist = 0;

#if ENABLE_FEATURE_CLEAN_UP
static void delete_block_backed_filesystems(void)
{
    llist_free(fslist, free);
}
#else
void delete_block_backed_filesystems(void);
#endif

#if ENABLE_FEATURE_MTAB_SUPPORT
static int useMtab = 1;
static int fakeIt;
#else
#define useMtab 0
#define fakeIt 0
#endif

// Perform actual mount of specific filesystem at specific location.
// NB: mp->xxx fields may be trashed on exit
static int mount_it_now(struct mntent *mp, int vfsflags, char *filteropts)
{
    int rc = 0;

    if (fakeIt) goto mtab;

    // Mount, with fallback to read-only if necessary.

    for (;;) {
        rc = mount(mp->mnt_fsname, mp->mnt_dir, mp->mnt_type,
                vfsflags, filteropts);
        if (!rc || (vfsflags&MS_RDONLY) || (errno!=EACCES && errno!=EROFS))
            break;
        bb_error_msg("%s is write-protected, mounting read-only",
                mp->mnt_fsname);
        vfsflags |= MS_RDONLY;
    }

    // Abort entirely if permission denied.

    if (rc && errno == EPERM)
        bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);

    /* If the mount was successful, and we're maintaining an old-style
     * mtab file by hand, add the new entry to it now. */
 mtab:
    if (ENABLE_FEATURE_MTAB_SUPPORT && useMtab && !rc && !(vfsflags & MS_REMOUNT)) {
        char *fsname;
        FILE *mountTable = setmntent(bb_path_mtab_file, "a+");
        int i;

        if (!mountTable) {
            bb_error_msg("no %s",bb_path_mtab_file);
            goto ret;
        }

        // Add vfs string flags

        for (i=0; mount_options[i].flags != MS_REMOUNT; i++)
            if (mount_options[i].flags > 0 && (mount_options[i].flags & vfsflags))
                append_mount_options(&(mp->mnt_opts), mount_options[i].name);

        // Remove trailing / (if any) from directory we mounted on

        i = strlen(mp->mnt_dir) - 1;
        if (i > 0 && mp->mnt_dir[i] == '/') mp->mnt_dir[i] = 0;

        // Convert to canonical pathnames as needed

        mp->mnt_dir = bb_simplify_path(mp->mnt_dir);
        fsname = 0;
        if (!mp->mnt_type || !*mp->mnt_type) { /* bind mount */
            mp->mnt_fsname = fsname = bb_simplify_path(mp->mnt_fsname);
            mp->mnt_type = (char*)"bind";
        }
        mp->mnt_freq = mp->mnt_passno = 0;

        // Write and close.

        addmntent(mountTable, mp);
        endmntent(mountTable);
        if (ENABLE_FEATURE_CLEAN_UP) {
            free(mp->mnt_dir);
            free(fsname);
        }
    }
 ret:
    return rc;
}

#if ENABLE_FEATURE_MOUNT_NFS

/*
 * Linux NFS mount
 * Copyright (C) 1993 Rick Sladkey <jrs@world.std.com>
 *
 * Licensed under GPLv2, see file LICENSE in this tarball for details.
 *
 * Wed Feb  8 12:51:48 1995, biro@yggdrasil.com (Ross Biro): allow all port
 * numbers to be specified on the command line.
 *
 * Fri, 8 Mar 1996 18:01:39, Swen Thuemmler <swen@uni-paderborn.de>:
 * Omit the call to connect() for Linux version 1.3.11 or later.
 *
 * Wed Oct  1 23:55:28 1997: Dick Streefland <dick_streefland@tasking.com>
 * Implemented the "bg", "fg" and "retry" mount options for NFS.
 *
 * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
 * - added Native Language Support
 *
 * Modified by Olaf Kirch and Trond Myklebust for new NFS code,
 * plus NFSv3 stuff.
 */

/* This is just a warning of a common mistake.  Possibly this should be a
 * uclibc faq entry rather than in busybox... */
#if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
#error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support."
#endif

#define MOUNTPORT 635
#define MNTPATHLEN 1024
#define MNTNAMLEN 255
#define FHSIZE 32
#define FHSIZE3 64

typedef char fhandle[FHSIZE];

typedef struct {
    unsigned int fhandle3_len;
    char *fhandle3_val;
} fhandle3;

enum mountstat3 {
    MNT_OK = 0,
    MNT3ERR_PERM = 1,
    MNT3ERR_NOENT = 2,
    MNT3ERR_IO = 5,
    MNT3ERR_ACCES = 13,
    MNT3ERR_NOTDIR = 20,
    MNT3ERR_INVAL = 22,
    MNT3ERR_NAMETOOLONG = 63,
    MNT3ERR_NOTSUPP = 10004,
    MNT3ERR_SERVERFAULT = 10006,
};
typedef enum mountstat3 mountstat3;

struct fhstatus {
    unsigned int fhs_status;
    union {
        fhandle fhs_fhandle;
    } fhstatus_u;
};
typedef struct fhstatus fhstatus;

struct mountres3_ok {
    fhandle3 fhandle;
    struct {
        unsigned int auth_flavours_len;
        char *auth_flavours_val;
    } auth_flavours;
};
typedef struct mountres3_ok mountres3_ok;

struct mountres3 {
    mountstat3 fhs_status;
    union {
        mountres3_ok mountinfo;
    } mountres3_u;
};
typedef struct mountres3 mountres3;

typedef char *dirpath;

typedef char *name;

typedef struct mountbody *mountlist;

struct mountbody {
    name ml_hostname;
    dirpath ml_directory;
    mountlist ml_next;
};
typedef struct mountbody mountbody;

typedef struct groupnode *groups;

struct groupnode {
    name gr_name;
    groups gr_next;
};
typedef struct groupnode groupnode;

typedef struct exportnode *exports;

struct exportnode {
    dirpath ex_dir;
    groups ex_groups;
    exports ex_next;
};
typedef struct exportnode exportnode;

struct ppathcnf {
    int pc_link_max;
    short pc_max_canon;
    short pc_max_input;
    short pc_name_max;
    short pc_path_max;
    short pc_pipe_buf;
    uint8_t pc_vdisable;
    char pc_xxx;
    short pc_mask[2];
};
typedef struct ppathcnf ppathcnf;

#define MOUNTPROG 100005
#define MOUNTVERS 1

#define MOUNTPROC_NULL 0
#define MOUNTPROC_MNT 1
#define MOUNTPROC_DUMP 2
#define MOUNTPROC_UMNT 3
#define MOUNTPROC_UMNTALL 4
#define MOUNTPROC_EXPORT 5
#define MOUNTPROC_EXPORTALL 6

#define MOUNTVERS_POSIX 2

#define MOUNTPROC_PATHCONF 7

#define MOUNT_V3 3

#define MOUNTPROC3_NULL 0
#define MOUNTPROC3_MNT 1
#define MOUNTPROC3_DUMP 2
#define MOUNTPROC3_UMNT 3
#define MOUNTPROC3_UMNTALL 4
#define MOUNTPROC3_EXPORT 5

enum {
#ifndef NFS_FHSIZE
    NFS_FHSIZE = 32,
#endif
#ifndef NFS_PORT
    NFS_PORT = 2049
#endif
};

/*
 * We want to be able to compile mount on old kernels in such a way
 * that the binary will work well on more recent kernels.
 * Thus, if necessary we teach nfsmount.c the structure of new fields
 * that will come later.
 *
 * Moreover, the new kernel includes conflict with glibc includes
 * so it is easiest to ignore the kernel altogether (at compile time).
 */

struct nfs2_fh {
    char                    data[32];
};
struct nfs3_fh {
    unsigned short          size;
    unsigned char           data[64];
};

struct nfs_mount_data {
    int     version;        /* 1 */
    int     fd;         /* 1 */
    struct nfs2_fh  old_root;       /* 1 */
    int     flags;          /* 1 */
    int     rsize;          /* 1 */
    int     wsize;          /* 1 */
    int     timeo;          /* 1 */
    int     retrans;        /* 1 */
    int     acregmin;       /* 1 */
    int     acregmax;       /* 1 */
    int     acdirmin;       /* 1 */
    int     acdirmax;       /* 1 */
    struct sockaddr_in addr;        /* 1 */
    char        hostname[256];      /* 1 */
    int     namlen;         /* 2 */
    unsigned int    bsize;          /* 3 */
    struct nfs3_fh  root;           /* 4 */
};

/* bits in the flags field */
enum {
    NFS_MOUNT_SOFT = 0x0001,    /* 1 */
    NFS_MOUNT_INTR = 0x0002,    /* 1 */
    NFS_MOUNT_SECURE = 0x0004,  /* 1 */
    NFS_MOUNT_POSIX = 0x0008,   /* 1 */
    NFS_MOUNT_NOCTO = 0x0010,   /* 1 */
    NFS_MOUNT_NOAC = 0x0020,    /* 1 */
    NFS_MOUNT_TCP = 0x0040,     /* 2 */
    NFS_MOUNT_VER3 = 0x0080,    /* 3 */
    NFS_MOUNT_KERBEROS = 0x0100,    /* 3 */
    NFS_MOUNT_NONLM = 0x0200    /* 3 */
};


/*
 * We need to translate between nfs status return values and
 * the local errno values which may not be the same.
 *
 * Andreas Schwab <schwab@LS5.informatik.uni-dortmund.de>: change errno:
 * "after #include <errno.h> the symbol errno is reserved for any use,
 *  it cannot even be used as a struct tag or field name".
 */

#ifndef EDQUOT
#define EDQUOT  ENOSPC
#endif

// Convert each NFSERR_BLAH into EBLAH

static const struct {
    int stat;
    int errnum;
} nfs_errtbl[] = {
    {0,0}, {1,EPERM}, {2,ENOENT}, {5,EIO}, {6,ENXIO}, {13,EACCES}, {17,EEXIST},
    {19,ENODEV}, {20,ENOTDIR}, {21,EISDIR}, {22,EINVAL}, {27,EFBIG},
    {28,ENOSPC}, {30,EROFS}, {63,ENAMETOOLONG}, {66,ENOTEMPTY}, {69,EDQUOT},
    {70,ESTALE}, {71,EREMOTE}, {-1,EIO}
};

static char *nfs_strerror(int status)
{
    int i;
    static char buf[sizeof("unknown nfs status return value: ") + sizeof(int)*3];

    for (i = 0; nfs_errtbl[i].stat != -1; i++) {
        if (nfs_errtbl[i].stat == status)
            return strerror(nfs_errtbl[i].errnum);
    }
    sprintf(buf, "unknown nfs status return value: %d", status);
    return buf;
}

static bool_t xdr_fhandle(XDR *xdrs, fhandle objp)
{
    if (!xdr_opaque(xdrs, objp, FHSIZE))
         return FALSE;
    return TRUE;
}

static bool_t xdr_fhstatus(XDR *xdrs, fhstatus *objp)
{
    if (!xdr_u_int(xdrs, &objp->fhs_status))
         return FALSE;
    switch (objp->fhs_status) {
    case 0:
        if (!xdr_fhandle(xdrs, objp->fhstatus_u.fhs_fhandle))
             return FALSE;
        break;
    default:
        break;
    }
    return TRUE;
}

static bool_t xdr_dirpath(XDR *xdrs, dirpath *objp)
{
    if (!xdr_string(xdrs, objp, MNTPATHLEN))
         return FALSE;
    return TRUE;
}

static bool_t xdr_fhandle3(XDR *xdrs, fhandle3 *objp)
{
    if (!xdr_bytes(xdrs, (char **)&objp->fhandle3_val, (unsigned int *) &objp->fhandle3_len, FHSIZE3))
         return FALSE;
    return TRUE;
}

static bool_t xdr_mountres3_ok(XDR *xdrs, mountres3_ok *objp)
{
    if (!xdr_fhandle3(xdrs, &objp->fhandle))
        return FALSE;
    if (!xdr_array(xdrs, &(objp->auth_flavours.auth_flavours_val), &(objp->auth_flavours.auth_flavours_len), ~0,
                sizeof (int), (xdrproc_t) xdr_int))
        return FALSE;
    return TRUE;
}

static bool_t xdr_mountstat3(XDR *xdrs, mountstat3 *objp)
{
    if (!xdr_enum(xdrs, (enum_t *) objp))
         return FALSE;
    return TRUE;
}

static bool_t xdr_mountres3(XDR *xdrs, mountres3 *objp)
{
    if (!xdr_mountstat3(xdrs, &objp->fhs_status))
        return FALSE;
    switch (objp->fhs_status) {
    case MNT_OK:
        if (!xdr_mountres3_ok(xdrs, &objp->mountres3_u.mountinfo))
             return FALSE;
        break;
    default:
        break;
    }
    return TRUE;
}

#define MAX_NFSPROT ((nfs_mount_version >= 4) ? 3 : 2)

/*
 * nfs_mount_version according to the sources seen at compile time.
 */
static int nfs_mount_version;
static int kernel_version;

/*
 * Unfortunately, the kernel prints annoying console messages
 * in case of an unexpected nfs mount version (instead of
 * just returning some error).  Therefore we'll have to try
 * and figure out what version the kernel expects.
 *
 * Variables:
 *  KERNEL_NFS_MOUNT_VERSION: kernel sources at compile time
 *  NFS_MOUNT_VERSION: these nfsmount sources at compile time
 *  nfs_mount_version: version this source and running kernel can handle
 */
static void
find_kernel_nfs_mount_version(void)
{
    if (kernel_version)
        return;

    nfs_mount_version = 4; /* default */

    kernel_version = get_linux_version_code();
    if (kernel_version) {
        if (kernel_version < KERNEL_VERSION(2,1,32))
            nfs_mount_version = 1;
        else if (kernel_version < KERNEL_VERSION(2,2,18) ||
                (kernel_version >= KERNEL_VERSION(2,3,0) &&
                 kernel_version < KERNEL_VERSION(2,3,99)))
            nfs_mount_version = 3;
        /* else v4 since 2.3.99pre4 */
    }
}

static struct pmap *
get_mountport(struct sockaddr_in *server_addr,
    long unsigned prog,
    long unsigned version,
    long unsigned proto,
    long unsigned port)
{
    struct pmaplist *pmap;
    static struct pmap p = {0, 0, 0, 0};

    server_addr->sin_port = PMAPPORT;
/* glibc 2.4 (still) has pmap_getmaps(struct sockaddr_in *).
 * I understand it like "IPv6 for this is not 100% ready" */
    pmap = pmap_getmaps(server_addr);

    if (version > MAX_NFSPROT)
        version = MAX_NFSPROT;
    if (!prog)
        prog = MOUNTPROG;
    p.pm_prog = prog;
    p.pm_vers = version;
    p.pm_prot = proto;
    p.pm_port = port;

    while (pmap) {
        if (pmap->pml_map.pm_prog != prog)
            goto next;
        if (!version && p.pm_vers > pmap->pml_map.pm_vers)
            goto next;
        if (version > 2 && pmap->pml_map.pm_vers != version)
            goto next;
        if (version && version <= 2 && pmap->pml_map.pm_vers > 2)
            goto next;
        if (pmap->pml_map.pm_vers > MAX_NFSPROT ||
            (proto && p.pm_prot && pmap->pml_map.pm_prot != proto) ||
            (port && pmap->pml_map.pm_port != port))
            goto next;
        memcpy(&p, &pmap->pml_map, sizeof(p));
next:
        pmap = pmap->pml_next;
    }
    if (!p.pm_vers)
        p.pm_vers = MOUNTVERS;
    if (!p.pm_port)
        p.pm_port = MOUNTPORT;
    if (!p.pm_prot)
        p.pm_prot = IPPROTO_TCP;
    return &p;
}

static int daemonize(void)
{
    int fd;
    int pid = fork();
    if (pid < 0) /* error */
        return -errno;
    if (pid > 0) /* parent */
        return 0;
    /* child */
    fd = xopen(bb_dev_null, O_RDWR);
    dup2(fd, 0);
    dup2(fd, 1);
    dup2(fd, 2);
    while (fd > 2) close(fd--);
    setsid();
    openlog(applet_name, LOG_PID, LOG_DAEMON);
    logmode = LOGMODE_SYSLOG;
    return 1;
}

// TODO
static inline int we_saw_this_host_before(const char *hostname)
{
    return 0;
}

/* RPC strerror analogs are terminally idiotic:
 * *mandatory* prefix and \n at end.
 * This hopefully helps. Usage:
 * error_msg_rpc(clnt_*error*(" ")) */
static void error_msg_rpc(const char *msg)
{
    int len;
    while (msg[0] == ' ' || msg[0] == ':') msg++;
    len = strlen(msg);
    while (len && msg[len-1] == '\n') len--;
    bb_error_msg("%.*s", len, msg);
}

// NB: mp->xxx fields may be trashed on exit
static int nfsmount(struct mntent *mp, int vfsflags, char *filteropts)
{
    CLIENT *mclient;
    char *hostname;
    char *pathname;
    char *mounthost;
    struct nfs_mount_data data;
    char *opt;
    struct hostent *hp;
    struct sockaddr_in server_addr;
    struct sockaddr_in mount_server_addr;
    int msock, fsock;
    union {
        struct fhstatus nfsv2;
        struct mountres3 nfsv3;
    } status;
    int daemonized;
    char *s;
    int port;
    int mountport;
    int proto;
    int bg;
    int soft;
    int intr;
    int posix;
    int nocto;
    int noac;
    int nolock;
    int retry;
    int tcp;
    int mountprog;
    int mountvers;
    int nfsprog;
    int nfsvers;
    int retval;

    find_kernel_nfs_mount_version();

    daemonized = 0;
    mounthost = NULL;
    retval = ETIMEDOUT;
    msock = fsock = -1;
    mclient = NULL;

    /* NB: hostname, mounthost, filteropts must be free()d prior to return */

    filteropts = xstrdup(filteropts); /* going to trash it later... */

    hostname = xstrdup(mp->mnt_fsname);
    /* mount_main() guarantees that ':' is there */
    s = strchr(hostname, ':');
    pathname = s + 1;
    *s = '\0';
    /* Ignore all but first hostname in replicated mounts
       until they can be fully supported. (mack@sgi.com) */
    s = strchr(hostname, ',');
    if (s) {
        *s = '\0';
        bb_error_msg("warning: multiple hostnames not supported");
    }

    server_addr.sin_family = AF_INET;
    if (!inet_aton(hostname, &server_addr.sin_addr)) {
        hp = gethostbyname(hostname);
        if (hp == NULL) {
            bb_herror_msg("%s", hostname);
            goto fail;
        }
        if (hp->h_length > sizeof(struct in_addr)) {
            bb_error_msg("got bad hp->h_length");
            hp->h_length = sizeof(struct in_addr);
        }
        memcpy(&server_addr.sin_addr,
                hp->h_addr, hp->h_length);
    }

    memcpy(&mount_server_addr, &server_addr, sizeof(mount_server_addr));

    /* add IP address to mtab options for use when unmounting */

    if (!mp->mnt_opts) { /* TODO: actually mp->mnt_opts is never NULL */
        mp->mnt_opts = xasprintf("addr=%s", inet_ntoa(server_addr.sin_addr));
    } else {
        char *tmp = xasprintf("%s%saddr=%s", mp->mnt_opts,
                    mp->mnt_opts[0] ? "," : "",
                    inet_ntoa(server_addr.sin_addr));
        free(mp->mnt_opts);
        mp->mnt_opts = tmp;
    }

    /* Set default options.
     * rsize/wsize (and bsize, for ver >= 3) are left 0 in order to
     * let the kernel decide.
     * timeo is filled in after we know whether it'll be TCP or UDP. */
    memset(&data, 0, sizeof(data));
    data.retrans    = 3;
    data.acregmin   = 3;
    data.acregmax   = 60;
    data.acdirmin   = 30;
    data.acdirmax   = 60;
    data.namlen = NAME_MAX;

    bg = 0;
    soft = 0;
    intr = 0;
    posix = 0;
    nocto = 0;
    nolock = 0;
    noac = 0;
    retry = 10000;      /* 10000 minutes ~ 1 week */
    tcp = 0;

    mountprog = MOUNTPROG;
    mountvers = 0;
    port = 0;
    mountport = 0;
    nfsprog = 100003;
    nfsvers = 0;

    /* parse options */
    if (filteropts) for (opt = strtok(filteropts, ","); opt; opt = strtok(NULL, ",")) {
        char *opteq = strchr(opt, '=');
        if (opteq) {
            static const char options[] ALIGN1 =
                /* 0 */ "rsize\0"
                /* 1 */ "wsize\0"
                /* 2 */ "timeo\0"
                /* 3 */ "retrans\0"
                /* 4 */ "acregmin\0"
                /* 5 */ "acregmax\0"
                /* 6 */ "acdirmin\0"
                /* 7 */ "acdirmax\0"
                /* 8 */ "actimeo\0"
                /* 9 */ "retry\0"
                /* 10 */ "port\0"
                /* 11 */ "mountport\0"
                /* 12 */ "mounthost\0"
                /* 13 */ "mountprog\0"
                /* 14 */ "mountvers\0"
                /* 15 */ "nfsprog\0"
                /* 16 */ "nfsvers\0"
                /* 17 */ "vers\0"
                /* 18 */ "proto\0"
                /* 19 */ "namlen\0"
                /* 20 */ "addr\0";
            int val = xatoi_u(opteq + 1);
            *opteq = '\0';
            switch (index_in_strings(options, opt)) {
            case 0: // "rsize"
                data.rsize = val;
                break;
            case 1: // "wsize"
                data.wsize = val;
                break;
            case 2: // "timeo"
                data.timeo = val;
                break;
            case 3: // "retrans"
                data.retrans = val;
                break;
            case 4: // "acregmin"
                data.acregmin = val;
                break;
            case 5: // "acregmax"
                data.acregmax = val;
                break;
            case 6: // "acdirmin"
                data.acdirmin = val;
                break;
            case 7: // "acdirmax"
                data.acdirmax = val;
                break;
            case 8: // "actimeo"
                data.acregmin = val;
                data.acregmax = val;
                data.acdirmin = val;
                data.acdirmax = val;
                break;
            case 9: // "retry"
                retry = val;
                break;
            case 10: // "port"
                port = val;
                break;
            case 11: // "mountport"
                mountport = val;
                break;
            case 12: // "mounthost"
                mounthost = xstrndup(opteq+1,
                        strcspn(opteq+1," \t\n\r,"));
                break;
            case 13: // "mountprog"
                mountprog = val;
                break;
            case 14: // "mountvers"
                mountvers = val;
                break;
            case 15: // "nfsprog"
                nfsprog = val;
                break;
            case 16: // "nfsvers"
            case 17: // "vers"
                nfsvers = val;
                break;
            case 18: // "proto"
                if (!strncmp(opteq+1, "tcp", 3))
                    tcp = 1;
                else if (!strncmp(opteq+1, "udp", 3))
                    tcp = 0;
                else
                    bb_error_msg("warning: unrecognized proto= option");
                break;
            case 19: // "namlen"
                if (nfs_mount_version >= 2)
                    data.namlen = val;
                else
                    bb_error_msg("warning: option namlen is not supported\n");
                break;
            case 20: // "addr" - ignore
                break;
            default:
                bb_error_msg("unknown nfs mount parameter: %s=%d", opt, val);
                goto fail;
            }
        }
        else {
            static const char options[] ALIGN1 =
                "bg\0"
                "fg\0"
                "soft\0"
                "hard\0"
                "intr\0"
                "posix\0"
                "cto\0"
                "ac\0"
                "tcp\0"
                "udp\0"
                "lock\0";
            int val = 1;
            if (!strncmp(opt, "no", 2)) {
                val = 0;
                opt += 2;
            }
            switch (index_in_strings(options, opt)) {
            case 0: // "bg"
                bg = val;
                break;
            case 1: // "fg"
                bg = !val;
                break;
            case 2: // "soft"
                soft = val;
                break;
            case 3: // "hard"
                soft = !val;
                break;
            case 4: // "intr"
                intr = val;
                break;
            case 5: // "posix"
                posix = val;
                break;
            case 6: // "cto"
                nocto = !val;
                break;
            case 7: // "ac"
                noac = !val;
                break;
            case 8: // "tcp"
                tcp = val;
                break;
            case 9: // "udp"
                tcp = !val;
                break;
            case 10: // "lock"
                if (nfs_mount_version >= 3)
                    nolock = !val;
                else
                    bb_error_msg("warning: option nolock is not supported");
                break;
            default:
                bb_error_msg("unknown nfs mount option: %s%s", val ? "" : "no", opt);
                goto fail;
            }
        }
    }
    proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;

    data.flags = (soft ? NFS_MOUNT_SOFT : 0)
        | (intr ? NFS_MOUNT_INTR : 0)
        | (posix ? NFS_MOUNT_POSIX : 0)
        | (nocto ? NFS_MOUNT_NOCTO : 0)
        | (noac ? NFS_MOUNT_NOAC : 0);
    if (nfs_mount_version >= 2)
        data.flags |= (tcp ? NFS_MOUNT_TCP : 0);
    if (nfs_mount_version >= 3)
        data.flags |= (nolock ? NFS_MOUNT_NONLM : 0);
    if (nfsvers > MAX_NFSPROT || mountvers > MAX_NFSPROT) {
        bb_error_msg("NFSv%d not supported", nfsvers);
        goto fail;
    }
    if (nfsvers && !mountvers)
        mountvers = (nfsvers < 3) ? 1 : nfsvers;
    if (nfsvers && nfsvers < mountvers) {
        mountvers = nfsvers;
    }

    /* Adjust options if none specified */
    if (!data.timeo)
        data.timeo = tcp ? 70 : 7;

    data.version = nfs_mount_version;

    if (vfsflags & MS_REMOUNT)
        goto do_mount;

    /*
     * If the previous mount operation on the same host was
     * backgrounded, and the "bg" for this mount is also set,
     * give up immediately, to avoid the initial timeout.
     */
    if (bg && we_saw_this_host_before(hostname)) {
        daemonized = daemonize(); /* parent or error */
        if (daemonized <= 0) { /* parent or error */
            retval = -daemonized;
            goto ret;
        }
    }

    /* create mount daemon client */
    /* See if the nfs host = mount host. */
    if (mounthost) {
        if (mounthost[0] >= '0' && mounthost[0] <= '9') {
            mount_server_addr.sin_family = AF_INET;
            mount_server_addr.sin_addr.s_addr = inet_addr(hostname);
        } else {
            hp = gethostbyname(mounthost);
            if (hp == NULL) {
                bb_herror_msg("%s", mounthost);
                goto fail;
            } else {
                if (hp->h_length > sizeof(struct in_addr)) {
                    bb_error_msg("got bad hp->h_length?");
                    hp->h_length = sizeof(struct in_addr);
                }
                mount_server_addr.sin_family = AF_INET;
                memcpy(&mount_server_addr.sin_addr,
                        hp->h_addr, hp->h_length);
            }
        }
    }

    /*
     * The following loop implements the mount retries. When the mount
     * times out, and the "bg" option is set, we background ourself
     * and continue trying.
     *
     * The case where the mount point is not present and the "bg"
     * option is set, is treated as a timeout. This is done to
     * support nested mounts.
     *
     * The "retry" count specified by the user is the number of
     * minutes to retry before giving up.
     */
    {
        struct timeval total_timeout;
        struct timeval retry_timeout;
        struct pmap* pm_mnt;
        time_t t;
        time_t prevt;
        time_t timeout;

        retry_timeout.tv_sec = 3;
        retry_timeout.tv_usec = 0;
        total_timeout.tv_sec = 20;
        total_timeout.tv_usec = 0;
        timeout = time(NULL) + 60 * retry;
        prevt = 0;
        t = 30;
retry:
        /* be careful not to use too many CPU cycles */
        if (t - prevt < 30)
            sleep(30);

        pm_mnt = get_mountport(&mount_server_addr,
                mountprog,
                mountvers,
                proto,
                mountport);
        nfsvers = (pm_mnt->pm_vers < 2) ? 2 : pm_mnt->pm_vers;

        /* contact the mount daemon via TCP */
        mount_server_addr.sin_port = htons(pm_mnt->pm_port);
        msock = RPC_ANYSOCK;

        switch (pm_mnt->pm_prot) {
        case IPPROTO_UDP:
            mclient = clntudp_create(&mount_server_addr,
                         pm_mnt->pm_prog,
                         pm_mnt->pm_vers,
                         retry_timeout,
                         &msock);
            if (mclient)
                break;
            mount_server_addr.sin_port = htons(pm_mnt->pm_port);
            msock = RPC_ANYSOCK;
        case IPPROTO_TCP:
            mclient = clnttcp_create(&mount_server_addr,
                         pm_mnt->pm_prog,
                         pm_mnt->pm_vers,
                         &msock, 0, 0);
            break;
        default:
            mclient = 0;
        }
        if (!mclient) {
            if (!daemonized && prevt == 0)
                error_msg_rpc(clnt_spcreateerror(" "));
        } else {
            enum clnt_stat clnt_stat;
            /* try to mount hostname:pathname */
            mclient->cl_auth = authunix_create_default();

            /* make pointers in xdr_mountres3 NULL so
             * that xdr_array allocates memory for us
             */
            memset(&status, 0, sizeof(status));

            if (pm_mnt->pm_vers == 3)
                clnt_stat = clnt_call(mclient, MOUNTPROC3_MNT,
                          (xdrproc_t) xdr_dirpath,
                          (caddr_t) &pathname,
                          (xdrproc_t) xdr_mountres3,
                          (caddr_t) &status,
                          total_timeout);
            else
                clnt_stat = clnt_call(mclient, MOUNTPROC_MNT,
                          (xdrproc_t) xdr_dirpath,
                          (caddr_t) &pathname,
                          (xdrproc_t) xdr_fhstatus,
                          (caddr_t) &status,
                          total_timeout);

            if (clnt_stat == RPC_SUCCESS)
                goto prepare_kernel_data; /* we're done */
            if (errno != ECONNREFUSED) {
                error_msg_rpc(clnt_sperror(mclient, " "));
                goto fail;  /* don't retry */
            }
            /* Connection refused */
            if (!daemonized && prevt == 0) /* print just once */
                error_msg_rpc(clnt_sperror(mclient, " "));
            auth_destroy(mclient->cl_auth);
            clnt_destroy(mclient);
            mclient = 0;
            close(msock);
        }

        /* Timeout. We are going to retry... maybe */

        if (!bg)
            goto fail;
        if (!daemonized) {
            daemonized = daemonize();
            if (daemonized <= 0) { /* parent or error */
                retval = -daemonized;
                goto ret;
            }
        }
        prevt = t;
        t = time(NULL);
        if (t >= timeout)
            /* TODO error message */
            goto fail;

        goto retry;
    }

prepare_kernel_data:

    if (nfsvers == 2) {
        if (status.nfsv2.fhs_status != 0) {
            bb_error_msg("%s:%s failed, reason given by server: %s",
                hostname, pathname,
                nfs_strerror(status.nfsv2.fhs_status));
            goto fail;
        }
        memcpy(data.root.data,
                (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
                NFS_FHSIZE);
        data.root.size = NFS_FHSIZE;
        memcpy(data.old_root.data,
                (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
                NFS_FHSIZE);
    } else {
        fhandle3 *my_fhandle;
        if (status.nfsv3.fhs_status != 0) {
            bb_error_msg("%s:%s failed, reason given by server: %s",
                hostname, pathname,
                nfs_strerror(status.nfsv3.fhs_status));
            goto fail;
        }
        my_fhandle = &status.nfsv3.mountres3_u.mountinfo.fhandle;
        memset(data.old_root.data, 0, NFS_FHSIZE);
        memset(&data.root, 0, sizeof(data.root));
        data.root.size = my_fhandle->fhandle3_len;
        memcpy(data.root.data,
                (char *) my_fhandle->fhandle3_val,
                my_fhandle->fhandle3_len);

        data.flags |= NFS_MOUNT_VER3;
    }

    /* create nfs socket for kernel */

    if (tcp) {
        if (nfs_mount_version < 3) {
            bb_error_msg("NFS over TCP is not supported");
            goto fail;
        }
        fsock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    } else
        fsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (fsock < 0) {
        bb_perror_msg("nfs socket");
        goto fail;
    }
    if (bindresvport(fsock, 0) < 0) {
        bb_perror_msg("nfs bindresvport");
        goto fail;
    }
    if (port == 0) {
        server_addr.sin_port = PMAPPORT;
        port = pmap_getport(&server_addr, nfsprog, nfsvers,
                    tcp ? IPPROTO_TCP : IPPROTO_UDP);
        if (port == 0)
            port = NFS_PORT;
    }
    server_addr.sin_port = htons(port);

    /* prepare data structure for kernel */

    data.fd = fsock;
    memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
    strncpy(data.hostname, hostname, sizeof(data.hostname));

    /* clean up */

    auth_destroy(mclient->cl_auth);
    clnt_destroy(mclient);
    close(msock);

    if (bg) {
        /* We must wait until mount directory is available */
        struct stat statbuf;
        int delay = 1;
        while (stat(mp->mnt_dir, &statbuf) == -1) {
            if (!daemonized) {
                daemonized = daemonize();
                if (daemonized <= 0) { /* parent or error */
                    retval = -daemonized;
                    goto ret;
                }
            }
            sleep(delay);   /* 1, 2, 4, 8, 16, 30, ... */
            delay *= 2;
            if (delay > 30)
                delay = 30;
        }
    }

do_mount: /* perform actual mount */

    mp->mnt_type = (char*)"nfs";
    retval = mount_it_now(mp, vfsflags, (char*)&data);
    goto ret;

fail:   /* abort */

    if (msock != -1) {
        if (mclient) {
            auth_destroy(mclient->cl_auth);
            clnt_destroy(mclient);
        }
        close(msock);
    }
    if (fsock != -1)
        close(fsock);

ret:
    free(hostname);
    free(mounthost);
    free(filteropts);
    return retval;
}

#else /* !ENABLE_FEATURE_MOUNT_NFS */

/* Never called. Call should be optimized out. */
int nfsmount(struct mntent *mp, int vfsflags, char *filteropts);

#endif /* !ENABLE_FEATURE_MOUNT_NFS */

// Mount one directory.  Handles CIFS, NFS, loopback, autobind, and filesystem
// type detection.  Returns 0 for success, nonzero for failure.
// NB: mp->xxx fields may be trashed on exit
static int singlemount(struct mntent *mp, int ignore_busy)
{
    int rc = -1, vfsflags;
    char *loopFile = 0, *filteropts = 0;
    llist_t *fl = 0;
    struct stat st;

    vfsflags = parse_mount_options(mp->mnt_opts, &filteropts);

    // Treat fstype "auto" as unspecified.

    if (mp->mnt_type && strcmp(mp->mnt_type,"auto") == 0)
        mp->mnt_type = 0;

    // Might this be an CIFS filesystem?

    if (ENABLE_FEATURE_MOUNT_CIFS
     && (!mp->mnt_type || strcmp(mp->mnt_type,"cifs") == 0)
     && (mp->mnt_fsname[0]=='/' || mp->mnt_fsname[0]=='\\')
     && mp->mnt_fsname[0]==mp->mnt_fsname[1]
    ) {
        len_and_sockaddr *lsa;
        char *ip, *dotted;
        char *s;

        rc = 1;
        // Replace '/' with '\' and verify that unc points to "//server/share".

        for (s = mp->mnt_fsname; *s; ++s)
            if (*s == '/') *s = '\\';

        // get server IP

        s = strrchr(mp->mnt_fsname, '\\');
        if (s <= mp->mnt_fsname+1) goto report_error;
        *s = '\0';
        lsa = host2sockaddr(mp->mnt_fsname+2, 0);
        *s = '\\';
        if (!lsa) goto report_error;

        // insert ip=... option into string flags.

        dotted = xmalloc_sockaddr2dotted_noport(&lsa->sa);
        ip = xasprintf("ip=%s", dotted);
        parse_mount_options(ip, &filteropts);

        // compose new unc '\\server-ip\share'
        // (s => slash after hostname)

        mp->mnt_fsname = xasprintf("\\\\%s%s", dotted, s);

        // lock is required
        vfsflags |= MS_MANDLOCK;

        mp->mnt_type = (char*)"cifs";
        rc = mount_it_now(mp, vfsflags, filteropts);
        if (ENABLE_FEATURE_CLEAN_UP) {
            free(mp->mnt_fsname);
            free(ip);
            free(dotted);
            free(lsa);
        }
        goto report_error;
    }

    // Might this be an NFS filesystem?

    if (ENABLE_FEATURE_MOUNT_NFS
     && (!mp->mnt_type || !strcmp(mp->mnt_type, "nfs"))
     && strchr(mp->mnt_fsname, ':') != NULL
    ) {
        rc = nfsmount(mp, vfsflags, filteropts);
        goto report_error;
    }

    // Look at the file.  (Not found isn't a failure for remount, or for
    // a synthetic filesystem like proc or sysfs.)
    // (We use stat, not lstat, in order to allow
    // mount symlink_to_file_or_blkdev dir)

    if (!stat(mp->mnt_fsname, &st)
     && !(vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE))
    ) {
        // Do we need to allocate a loopback device for it?

        if (ENABLE_FEATURE_MOUNT_LOOP && S_ISREG(st.st_mode)) {
            loopFile = bb_simplify_path(mp->mnt_fsname);
            mp->mnt_fsname = NULL; /* will receive malloced loop dev name */
            if (set_loop(&(mp->mnt_fsname), loopFile, 0) < 0) {
                if (errno == EPERM || errno == EACCES)
                    bb_error_msg(bb_msg_perm_denied_are_you_root);
                else
                    bb_perror_msg("cannot setup loop device");
                return errno;
            }

        // Autodetect bind mounts

        } else if (S_ISDIR(st.st_mode) && !mp->mnt_type)
            vfsflags |= MS_BIND;
    }

    /* If we know the fstype (or don't need to), jump straight
     * to the actual mount. */

    if (mp->mnt_type || (vfsflags & (MS_REMOUNT | MS_BIND | MS_MOVE)))
        rc = mount_it_now(mp, vfsflags, filteropts);
    else {
        // Loop through filesystem types until mount succeeds
        // or we run out

        /* Initialize list of block backed filesystems.  This has to be
         * done here so that during "mount -a", mounts after /proc shows up
         * can autodetect. */

        if (!fslist) {
            fslist = get_block_backed_filesystems();
            if (ENABLE_FEATURE_CLEAN_UP && fslist)
                atexit(delete_block_backed_filesystems);
        }

        for (fl = fslist; fl; fl = fl->link) {
            mp->mnt_type = fl->data;
            rc = mount_it_now(mp, vfsflags, filteropts);
            if (!rc) break;
        }
    }

    // If mount failed, clean up loop file (if any).

    if (ENABLE_FEATURE_MOUNT_LOOP && rc && loopFile) {
        del_loop(mp->mnt_fsname);
        if (ENABLE_FEATURE_CLEAN_UP) {
            free(loopFile);
            free(mp->mnt_fsname);
        }
    }

 report_error:
    if (ENABLE_FEATURE_CLEAN_UP)
        free(filteropts);

    if (rc && errno == EBUSY && ignore_busy)
        rc = 0;
    if (rc < 0)
        bb_perror_msg("mounting %s on %s failed", mp->mnt_fsname, mp->mnt_dir);

    return rc;
}

// Parse options, if necessary parse fstab/mtab, and call singlemount for
// each directory to be mounted.

static const char must_be_root[] ALIGN1 = "you must be root";

int mount_main(int argc, char **argv);
int mount_main(int argc, char **argv)
{
    enum { OPT_ALL = 0x10 };

    char *cmdopts = xstrdup(""), *fstype=0, *storage_path=0;
    char *opt_o;
    const char *fstabname;
    FILE *fstab;
    int i, j, rc = 0;
    unsigned opt;
    struct mntent mtpair[2], *mtcur = mtpair;
    SKIP_DESKTOP(const int nonroot = 0;)
    USE_DESKTOP( int nonroot = (getuid() != 0);)

    /* parse long options, like --bind and --move.  Note that -o option
     * and --option are synonymous.  Yes, this means --remount,rw works. */

    for (i = j = 0; i < argc; i++) {
        if (argv[i][0] == '-' && argv[i][1] == '-') {
            append_mount_options(&cmdopts, argv[i]+2);
        } else argv[j++] = argv[i];
    }
    argv[j] = 0;
    argc = j;

    // Parse remaining options

    opt = getopt32(argv, "o:t:rwanfvs", &opt_o, &fstype);
    if (opt & 0x1) append_mount_options(&cmdopts, opt_o); // -o
    //if (opt & 0x2) // -t
    if (opt & 0x4) append_mount_options(&cmdopts, "ro"); // -r
    if (opt & 0x8) append_mount_options(&cmdopts, "rw"); // -w
    //if (opt & 0x10) // -a
    if (opt & 0x20) USE_FEATURE_MTAB_SUPPORT(useMtab = 0); // -n
    if (opt & 0x40) USE_FEATURE_MTAB_SUPPORT(fakeIt = 1); // -f
    //if (opt & 0x80) // -v: verbose (ignore)
    //if (opt & 0x100) // -s: sloppy (ignore)
    argv += optind;
    argc -= optind;

    // Three or more non-option arguments?  Die with a usage message.

    if (argc > 2) bb_show_usage();

    // If we have no arguments, show currently mounted filesystems

    if (!argc) {
        if (!(opt & OPT_ALL)) {
            FILE *mountTable = setmntent(bb_path_mtab_file, "r");

            if (!mountTable) bb_error_msg_and_die("no %s", bb_path_mtab_file);

            while (getmntent_r(mountTable, mtpair, bb_common_bufsiz1,
                                sizeof(bb_common_bufsiz1)))
            {
                // Don't show rootfs. FIXME: why??
                // util-linux 2.12a happily shows rootfs...
                //if (!strcmp(mtpair->mnt_fsname, "rootfs")) continue;

                if (!fstype || !strcmp(mtpair->mnt_type, fstype))
                    printf("%s on %s type %s (%s)\n", mtpair->mnt_fsname,
                            mtpair->mnt_dir, mtpair->mnt_type,
                            mtpair->mnt_opts);
            }
            if (ENABLE_FEATURE_CLEAN_UP) endmntent(mountTable);
            return EXIT_SUCCESS;
        }
    } else storage_path = bb_simplify_path(argv[0]);

    // When we have two arguments, the second is the directory and we can
    // skip looking at fstab entirely.  We can always abspath() the directory
    // argument when we get it.

    if (argc == 2) {
        if (nonroot)
            bb_error_msg_and_die(must_be_root);
        mtpair->mnt_fsname = argv[0];
        mtpair->mnt_dir = argv[1];
        mtpair->mnt_type = fstype;
        mtpair->mnt_opts = cmdopts;
        rc = singlemount(mtpair, 0);
        goto clean_up;
    }

    i = parse_mount_options(cmdopts, 0);
    if (nonroot && (i & ~MS_SILENT)) // Non-root users cannot specify flags
        bb_error_msg_and_die(must_be_root);

    // If we have a shared subtree flag, don't worry about fstab or mtab.

    if (ENABLE_FEATURE_MOUNT_FLAGS
     && (i & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
    ) {
        rc = mount("", argv[0], "", i, "");
        if (rc) bb_perror_msg_and_die("%s", argv[0]);
        goto clean_up;
    }

    // Open either fstab or mtab

    fstabname = "/etc/fstab";
    if (i & MS_REMOUNT) {
        fstabname = bb_path_mtab_file;
    }
    fstab = setmntent(fstabname, "r");
    if (!fstab)
        bb_perror_msg_and_die("cannot read %s", fstabname);

    // Loop through entries until we find what we're looking for.

    memset(mtpair, 0, sizeof(mtpair));
    for (;;) {
        struct mntent *mtnext = (mtcur==mtpair ? mtpair+1 : mtpair);

        // Get next fstab entry

        if (!getmntent_r(fstab, mtcur, bb_common_bufsiz1
                    + (mtcur==mtpair ? sizeof(bb_common_bufsiz1)/2 : 0),
                sizeof(bb_common_bufsiz1)/2))
        {
            // Were we looking for something specific?

            if (argc) {

                // If we didn't find anything, complain.

                if (!mtnext->mnt_fsname)
                    bb_error_msg_and_die("can't find %s in %s",
                        argv[0], fstabname);

                mtcur = mtnext;
                if (nonroot) {
                    // fstab must have "users" or "user"
                    if (!(parse_mount_options(mtcur->mnt_opts, 0) & MOUNT_USERS))
                        bb_error_msg_and_die(must_be_root);
                }

                // Mount the last thing we found.

                mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
                append_mount_options(&(mtcur->mnt_opts), cmdopts);
                rc = singlemount(mtcur, 0);
                free(mtcur->mnt_opts);
            }
            goto clean_up;
        }

        /* If we're trying to mount something specific and this isn't it,
         * skip it.  Note we must match both the exact text in fstab (ala
         * "proc") or a full path from root */

        if (argc) {

            // Is this what we're looking for?

            if (strcmp(argv[0], mtcur->mnt_fsname) &&
               strcmp(storage_path, mtcur->mnt_fsname) &&
               strcmp(argv[0], mtcur->mnt_dir) &&
               strcmp(storage_path, mtcur->mnt_dir)) continue;

            // Remember this entry.  Something later may have overmounted
            // it, and we want the _last_ match.

            mtcur = mtnext;

        // If we're mounting all.

        } else {
            // Do we need to match a filesystem type?
            if (fstype && match_fstype(mtcur, fstype)) continue;

            // Skip noauto and swap anyway.

            if (parse_mount_options(mtcur->mnt_opts, 0)
                & (MOUNT_NOAUTO | MOUNT_SWAP)) continue;

            // No, mount -a won't mount anything,
            // even user mounts, for mere humans.

            if (nonroot)
                bb_error_msg_and_die(must_be_root);

            // Mount this thing.

            // NFS mounts want this to be xrealloc-able
            mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
            if (singlemount(mtcur, 1)) {
                /* Count number of failed mounts */
                rc++;
            }
            free(mtcur->mnt_opts);
        }
    }
    if (ENABLE_FEATURE_CLEAN_UP) endmntent(fstab);

clean_up:

    if (ENABLE_FEATURE_CLEAN_UP) {
        free(storage_path);
        free(cmdopts);
    }

    return rc;
}