fuse.c

/**
 * @file dll/fuse/fuse.c
 *
 * @copyright 2015-2020 Bill Zissimopoulos
 */
/*
 * This file is part of WinFsp.
 *
 * You can redistribute it and/or modify it under the terms of the GNU
 * General Public License version 3 as published by the Free Software
 * Foundation.
 *
 * Licensees holding a valid commercial license may use this software
 * in accordance with the commercial license agreement provided in
 * conjunction with the software.  The terms and conditions of any such
 * commercial license agreement shall govern, supersede, and render
 * ineffective any application of the GPLv3 license to this software,
 * notwithstanding of any reference thereto in the software or
 * associated repository.
 */

#include <dll/fuse/library.h>

struct fuse_chan
{
    PWSTR MountPoint;
    UINT8 Buffer[];
};

#define FSP_FUSE_CORE_OPT(n, f, v)      { n, offsetof(struct fsp_fuse_core_opt_data, f), v }
#define FSP_FUSE_CORE_OPT_NOHELP_IDX    4

static struct fuse_opt fsp_fuse_core_opts[] =
{
    FUSE_OPT_KEY("-h", 'h'),
    FUSE_OPT_KEY("--help", 'h'),
    FUSE_OPT_KEY("-V", 'V'),
    FUSE_OPT_KEY("--version", 'V'),
    FUSE_OPT_KEY("-d", FUSE_OPT_KEY_KEEP),
    FUSE_OPT_KEY("debug", FUSE_OPT_KEY_KEEP),
    FSP_FUSE_CORE_OPT("-d", debug, 1),
    FSP_FUSE_CORE_OPT("debug", debug, 1),

    FUSE_OPT_KEY("DebugLog=", 'D'),

    FUSE_OPT_KEY("hard_remove", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("use_ino", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("readdir_ino", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("direct_io", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("kernel_cache", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("auto_cache", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("noauto_cache", FUSE_OPT_KEY_DISCARD),
    FSP_FUSE_CORE_OPT("umask=", set_umask, 1),
    FSP_FUSE_CORE_OPT("umask=%o", umask, 0),
    FSP_FUSE_CORE_OPT("create_umask=", set_create_umask, 1),
    FSP_FUSE_CORE_OPT("create_umask=%o", create_umask, 0),
    FSP_FUSE_CORE_OPT("create_file_umask=", set_create_file_umask, 1),
    FSP_FUSE_CORE_OPT("create_file_umask=%o", create_file_umask, 0),
    FSP_FUSE_CORE_OPT("create_dir_umask=", set_create_dir_umask, 1),
    FSP_FUSE_CORE_OPT("create_dir_umask=%o", create_dir_umask, 0),
    FSP_FUSE_CORE_OPT("uid=", set_uid, 1),
    FSP_FUSE_CORE_OPT("uid=%d", uid, 0),
    FSP_FUSE_CORE_OPT("gid=", set_gid, 1),
    FSP_FUSE_CORE_OPT("gid=%d", gid, 0),
    FUSE_OPT_KEY("entry_timeout", FUSE_OPT_KEY_DISCARD),
    FSP_FUSE_CORE_OPT("attr_timeout=", set_attr_timeout, 1),
    FSP_FUSE_CORE_OPT("attr_timeout=%d", attr_timeout, 0),
    FUSE_OPT_KEY("ac_attr_timeout", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("negative_timeout", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("noforget", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("intr", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("intr_signal=", FUSE_OPT_KEY_DISCARD),
    FUSE_OPT_KEY("modules=", FUSE_OPT_KEY_DISCARD),

    FSP_FUSE_CORE_OPT("rellinks", rellinks, 1),
    FSP_FUSE_CORE_OPT("norellinks", rellinks, 0),

    FSP_FUSE_CORE_OPT("dothidden", dothidden, 1),
    FSP_FUSE_CORE_OPT("nodothidden", dothidden, 0),

    FUSE_OPT_KEY("fstypename=", 'F'),
    FUSE_OPT_KEY("volname=", 'v'),

    FSP_FUSE_CORE_OPT("SectorSize=%hu", VolumeParams.SectorSize, 4096),
    FSP_FUSE_CORE_OPT("SectorsPerAllocationUnit=%hu", VolumeParams.SectorsPerAllocationUnit, 1),
    FSP_FUSE_CORE_OPT("MaxComponentLength=%hu", VolumeParams.MaxComponentLength, 0),
    FSP_FUSE_CORE_OPT("VolumeCreationTime=%lli", VolumeParams.VolumeCreationTime, 0),
    FSP_FUSE_CORE_OPT("VolumeSerialNumber=%lx", VolumeParams.VolumeSerialNumber, 0),
    FSP_FUSE_CORE_OPT("FileInfoTimeout=", set_FileInfoTimeout, 1),
    FSP_FUSE_CORE_OPT("FileInfoTimeout=%d", VolumeParams.FileInfoTimeout, 0),
    FSP_FUSE_CORE_OPT("DirInfoTimeout=", set_DirInfoTimeout, 1),
    FSP_FUSE_CORE_OPT("DirInfoTimeout=%d", VolumeParams.DirInfoTimeout, 0),
    FSP_FUSE_CORE_OPT("EaTimeout=", set_EaTimeout, 1),
    FSP_FUSE_CORE_OPT("EaTimeout=%d", VolumeParams.EaTimeout, 0),
    FSP_FUSE_CORE_OPT("VolumeInfoTimeout=", set_VolumeInfoTimeout, 1),
    FSP_FUSE_CORE_OPT("VolumeInfoTimeout=%d", VolumeParams.VolumeInfoTimeout, 0),
    FSP_FUSE_CORE_OPT("KeepFileCache=", set_KeepFileCache, 1),
    FSP_FUSE_CORE_OPT("ThreadCount=%u", ThreadCount, 0),
    FUSE_OPT_KEY("UNC=", 'U'),
    FUSE_OPT_KEY("--UNC=", 'U'),
    FUSE_OPT_KEY("VolumePrefix=", 'U'),
    FUSE_OPT_KEY("--VolumePrefix=", 'U'),
    FUSE_OPT_KEY("FileSystemName=", 'F'),
    FUSE_OPT_KEY("--FileSystemName=", 'F'),
    FUSE_OPT_KEY("ExactFileSystemName=", 'E'),
    FUSE_OPT_KEY("--ExactFileSystemName=", 'E'),

    FSP_FUSE_CORE_OPT("UserName=", set_uid, 1),
    FUSE_OPT_KEY("UserName=", 'u'),
    FSP_FUSE_CORE_OPT("--UserName=", set_uid, 1),
    FUSE_OPT_KEY("--UserName=", 'u'),
    FSP_FUSE_CORE_OPT("GroupName=", set_gid, 1),
    FUSE_OPT_KEY("GroupName=", 'g'),
    FSP_FUSE_CORE_OPT("--GroupName=", set_gid, 1),
    FUSE_OPT_KEY("--GroupName=", 'g'),

    FUSE_OPT_END,
};

static INIT_ONCE fsp_fuse_initonce = INIT_ONCE_STATIC_INIT;
DWORD fsp_fuse_tlskey = TLS_OUT_OF_INDEXES;

static BOOL WINAPI fsp_fuse_initialize(
    PINIT_ONCE InitOnce, PVOID Parameter, PVOID *Context)
{
    fsp_fuse_tlskey = TlsAlloc();
    return TRUE;
}

VOID fsp_fuse_finalize(BOOLEAN Dynamic)
{
    /*
     * This function is called during DLL_PROCESS_DETACH. We must therefore keep
     * finalization tasks to a minimum.
     *
     * We must free our TLS key (if any). We only do so if the library
     * is being explicitly unloaded (rather than the process exiting).
     */

    if (Dynamic && TLS_OUT_OF_INDEXES != fsp_fuse_tlskey)
    {
        /* !!!:
         * We should also free all thread local contexts, which means putting them in a list,
         * protected with a critical section, etc. Arghhh!
         *
         * I am too lazy and I am not going to do that, unless people start using this
         * DLL dynamically (LoadLibrary/FreeLibrary).
         */
        TlsFree(fsp_fuse_tlskey);
    }
}

VOID fsp_fuse_finalize_thread(VOID)
{
    struct fuse_context *context;

    if (TLS_OUT_OF_INDEXES != fsp_fuse_tlskey)
    {
        context = TlsGetValue(fsp_fuse_tlskey);
        if (0 != context)
        {
            fsp_fuse_obj_free(FSP_FUSE_HDR_FROM_CONTEXT(context));
            TlsSetValue(fsp_fuse_tlskey, 0);
        }
    }
}

FSP_FUSE_API int fsp_fuse_version(struct fsp_fuse_env *env)
{
    return FUSE_VERSION;
}

FSP_FUSE_API struct fuse_chan *fsp_fuse_mount(struct fsp_fuse_env *env,
    const char *mountpoint, struct fuse_args *args)
{
    struct fuse_chan *ch = 0;
    WCHAR TempMountPointBuf[MAX_PATH], MountPointBuf[MAX_PATH];
    int Size;

    if (0 == mountpoint || '\0' == mountpoint[0] ||
        ('*' == mountpoint[0] && '\0' == mountpoint[1]))
    {
        MountPointBuf[0] = L'*';
        MountPointBuf[1] = L'\0';
        Size = 2 * sizeof(WCHAR);
    }
    else if (
        (
            ('A' <= mountpoint[0] && mountpoint[0] <= 'Z') ||
            ('a' <= mountpoint[0] && mountpoint[0] <= 'z')
        ) &&
        ':' == mountpoint[1] && '\0' == mountpoint[2])
    {
        MountPointBuf[0] = mountpoint[0];
        MountPointBuf[1] = ':';
        MountPointBuf[2] = '\0';
        Size = 3 * sizeof(WCHAR);
    }
    else
    {
        char *win_mountpoint = 0;

        if (0 != env->conv_to_win_path)
            mountpoint = win_mountpoint = env->conv_to_win_path(mountpoint);

        Size = 0;
        if (0 != mountpoint &&
            0 != MultiByteToWideChar(CP_UTF8, 0, mountpoint, -1, TempMountPointBuf, MAX_PATH))
            Size = GetFullPathNameW(TempMountPointBuf, MAX_PATH, MountPointBuf, 0);

        env->memfree(win_mountpoint);

        if (0 == Size || MAX_PATH <= Size)
            goto fail;

        mountpoint = 0;
        Size = (Size + 1) * sizeof(WCHAR);
    }

    ch = fsp_fuse_obj_alloc(env, sizeof *ch + Size);
    if (0 == ch)
        goto fail;

    ch->MountPoint = (PVOID)ch->Buffer;
    memcpy(ch->MountPoint, MountPointBuf, Size);

    return ch;

fail:
    fsp_fuse_obj_free(ch);

    return 0;
}

FSP_FUSE_API void fsp_fuse_unmount(struct fsp_fuse_env *env,
    const char *mountpoint, struct fuse_chan *ch)
{
    fsp_fuse_obj_free(ch);
}

FSP_FUSE_API int fsp_fuse_is_lib_option(struct fsp_fuse_env *env,
    const char *opt)
{
    return fsp_fuse_opt_match(env, fsp_fuse_core_opts, opt);
}

static int fsp_fuse_username_to_uid(const char *username, int *puid)
{
    union
    {
        SID V;
        UINT8 B[SECURITY_MAX_SID_SIZE];
    } SidBuf;
    char Name[256], Domn[256];
    DWORD SidSize, NameSize, DomnSize;
    SID_NAME_USE Use;
    UINT32 Uid;
    NTSTATUS Result;

    *puid = 0;

    NameSize = lstrlenA(username) + 1;
    if (sizeof Name / sizeof Name[0] < NameSize)
        return -1;
    memcpy(Name, username, NameSize);
    for (PSTR P = Name, EndP = P + NameSize; EndP > P; P++)
        if ('+' == *P)
            *P = '\\';

    SidSize = sizeof SidBuf;
    DomnSize = sizeof Domn / sizeof Domn[0];
    if (!LookupAccountNameA(0, Name, &SidBuf, &SidSize, Domn, &DomnSize, &Use))
        return -1;

    Result = FspPosixMapSidToUid(&SidBuf, &Uid);
    if (!NT_SUCCESS(Result))
        return -1;

    *puid = Uid;

    return 0;
}

static int fsp_fuse_core_opt_proc(void *opt_data0, const char *arg, int key,
    struct fuse_args *outargs)
{
    struct fsp_fuse_core_opt_data *opt_data = opt_data0;

    switch (key)
    {
    default:
        return 1;
    case 'h':
        /* Note: The limit on FspServiceLog messages is 1024 bytes. */
        FspServiceLog(EVENTLOG_ERROR_TYPE, L""
            FSP_FUSE_LIBRARY_NAME " options:\n"
            "    -o umask=MASK              set file permissions (octal)\n"
            "    -o create_umask=MASK       set newly created file permissions (octal)\n"
            "        -o create_file_umask=MASK      for files only\n"
            "        -o create_dir_umask=MASK       for directories only\n"
            "    -o uid=N                   set file owner (-1 for mounting user id)\n"
            "    -o gid=N                   set file group (-1 for mounting user group)\n"
            "    -o rellinks                interpret absolute symlinks as volume relative\n"
            "    -o dothidden               dot files have the Windows hidden file attrib\n"
            "    -o volname=NAME            set volume label\n"
            "    -o VolumePrefix=UNC        set UNC prefix (/Server/Share)\n"
            "        --VolumePrefix=UNC     set UNC prefix (\\Server\\Share)\n"
            "    -o FileSystemName=NAME     set file system name\n"
            "    -o DebugLog=FILE           debug log file (requires -d)\n"
            );
        FspServiceLog(EVENTLOG_ERROR_TYPE, L""
            FSP_FUSE_LIBRARY_NAME " advanced options:\n"
            "    -o FileInfoTimeout=N       metadata timeout (millis, -1 for data caching)\n"
            "    -o DirInfoTimeout=N        directory info timeout (millis)\n"
            "    -o EaTimeout=N             extended attribute timeout (millis)\n"
            "    -o VolumeInfoTimeout=N     volume info timeout (millis)\n"
            "    -o KeepFileCache           do not discard cache when files are closed\n"
            "    -o ThreadCount             number of file system dispatcher threads\n"
            );
        opt_data->help = 1;
        return 1;
    case 'V':
        FspServiceLog(EVENTLOG_ERROR_TYPE, L""
            FSP_FUSE_LIBRARY_NAME " version %d.%d",
            FUSE_MAJOR_VERSION, FUSE_MINOR_VERSION);
        opt_data->help = 1;
        return 1;
    case 'D':
        arg += sizeof "DebugLog=" - 1;
        opt_data->DebugLogHandle = CreateFileA(
            arg,
            FILE_APPEND_DATA,
            FILE_SHARE_READ | FILE_SHARE_WRITE,
            0,
            OPEN_ALWAYS,
            FILE_ATTRIBUTE_NORMAL,
            0);
        return 0;
    case 'U':
        if ('U' == arg[0])
            arg += sizeof "UNC=" - 1;
        else if ('U' == arg[2])
            arg += sizeof "--UNC=" - 1;
        else if ('V' == arg[0])
            arg += sizeof "VolumePrefix=" - 1;
        else if ('V' == arg[2])
            arg += sizeof "--VolumePrefix=" - 1;
        if (0 == MultiByteToWideChar(CP_UTF8, 0, arg, -1,
            opt_data->VolumeParams.Prefix, sizeof opt_data->VolumeParams.Prefix / sizeof(WCHAR)))
            return -1;
        opt_data->VolumeParams.Prefix
            [sizeof opt_data->VolumeParams.Prefix / sizeof(WCHAR) - 1] = L'\0';
        for (PWSTR P = opt_data->VolumeParams.Prefix; *P; P++)
            if (L'/' == *P)
                *P = '\\';
        return 0;
    case 'F':
        if ('f' == arg[0])
            arg += sizeof "fstypename=" - 1;
        else if ('F' == arg[0])
            arg += sizeof "FileSystemName=" - 1;
        else if ('F' == arg[2])
            arg += sizeof "--FileSystemName=" - 1;
        if (0 == MultiByteToWideChar(CP_UTF8, 0, arg, -1,
            opt_data->VolumeParams.FileSystemName + 5,
            sizeof opt_data->VolumeParams.FileSystemName / sizeof(WCHAR) - 5))
            return -1;
        opt_data->VolumeParams.FileSystemName
            [sizeof opt_data->VolumeParams.FileSystemName / sizeof(WCHAR) - 1] = L'\0';
        memcpy(opt_data->VolumeParams.FileSystemName, L"FUSE-", 5 * sizeof(WCHAR));
        return 0;
    case 'E':
        if ('E' == arg[0])
            arg += sizeof "ExactFileSystemName=" - 1;
        else if ('E' == arg[2])
            arg += sizeof "--ExactFileSystemName=" - 1;
        if (0 == MultiByteToWideChar(CP_UTF8, 0, arg, -1,
            opt_data->VolumeParams.FileSystemName,
            sizeof opt_data->VolumeParams.FileSystemName / sizeof(WCHAR)))
            return -1;
        opt_data->VolumeParams.FileSystemName
            [sizeof opt_data->VolumeParams.FileSystemName / sizeof(WCHAR) - 1] = L'\0';
        return 0;
    case 'u':
        if ('U' == arg[0])
            arg += sizeof "UserName=" - 1;
        else if ('U' == arg[2])
            arg += sizeof "--UserName=" - 1;
        if (-1 == fsp_fuse_username_to_uid(arg, &opt_data->uid))
        {
            opt_data->username_to_uid_result = -1;
            return -1;
        }
        return 0;
    case 'g':
        if ('G' == arg[0])
            arg += sizeof "GroupName=" - 1;
        else if ('G' == arg[2])
            arg += sizeof "--GroupName=" - 1;
        if (-1 == fsp_fuse_username_to_uid(arg, &opt_data->gid))
        {
            opt_data->username_to_uid_result = -1;
            return -1;
        }
        return 0;
    case 'v':
        arg += sizeof "volname=" - 1;
        opt_data->VolumeLabelLength = (UINT16)(sizeof(WCHAR) *
            MultiByteToWideChar(CP_UTF8, 0, arg, lstrlenA(arg),
            opt_data->VolumeLabel, sizeof opt_data->VolumeLabel / sizeof(WCHAR)));
        if (0 == opt_data->VolumeLabelLength)
            return -1;
        return 0;
    }
}

int fsp_fuse_core_opt_parse(struct fsp_fuse_env *env,
    struct fuse_args *args, struct fsp_fuse_core_opt_data *opt_data,
    int help)
{
    if (help)
        return fsp_fuse_opt_parse(env, args, opt_data,
            fsp_fuse_core_opts, fsp_fuse_core_opt_proc);
    else
        return fsp_fuse_opt_parse(env, args, opt_data,
            fsp_fuse_core_opts + FSP_FUSE_CORE_OPT_NOHELP_IDX, fsp_fuse_core_opt_proc);
}

FSP_FUSE_API struct fuse *fsp_fuse_new(struct fsp_fuse_env *env,
    struct fuse_chan *ch, struct fuse_args *args,
    const struct fuse_operations *ops, size_t opsize, void *data)
{
    struct fuse *f = 0;
    struct fsp_fuse_core_opt_data opt_data;
    ULONG Size;
    PWSTR ErrorMessage = L".";
    NTSTATUS Result;

    if (opsize > sizeof(struct fuse_operations))
        opsize = sizeof(struct fuse_operations);

    memset(&opt_data, 0, sizeof opt_data);
    opt_data.env = env;
    opt_data.DebugLogHandle = GetStdHandle(STD_ERROR_HANDLE);
    opt_data.VolumeParams.Version = sizeof(FSP_FSCTL_VOLUME_PARAMS);
    opt_data.VolumeParams.FileInfoTimeout = 1000;
    opt_data.VolumeParams.FlushAndPurgeOnCleanup = TRUE;

    if (-1 == fsp_fuse_core_opt_parse(env, args, &opt_data, /*help=*/1))
    {
        if (-1 == opt_data.username_to_uid_result)
        {
            ErrorMessage = L": invalid user or group name.";
            goto fail;
        }
        return 0;
    }
    if (opt_data.help)
        return 0;

    if (opt_data.debug)
    {
        if (INVALID_HANDLE_VALUE == opt_data.DebugLogHandle)
        {
            ErrorMessage = L": cannot open debug log file.";
            goto fail;
        }
        FspDebugLogSetHandle(opt_data.DebugLogHandle);
    }

    if ((opt_data.set_uid && -1 == opt_data.uid) ||
        (opt_data.set_gid && -1 == opt_data.gid))
    {
        HANDLE Token;

        if (OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &Token))
        {
            fsp_fuse_get_token_uidgid(Token, TokenUser,
                opt_data.set_uid && -1 == opt_data.uid ? &opt_data.uid : 0,
                opt_data.set_gid && -1 == opt_data.gid ? &opt_data.gid : 0);

            CloseHandle(Token);
        }

        if ((opt_data.set_uid && -1 == opt_data.uid) ||
            (opt_data.set_gid && -1 == opt_data.gid))
        {
            ErrorMessage = L": unknown user/group.";
            goto fail;
        }
    }

    if (!opt_data.set_FileInfoTimeout && opt_data.set_attr_timeout)
        opt_data.VolumeParams.FileInfoTimeout = opt_data.attr_timeout * 1000;
    if (opt_data.set_DirInfoTimeout)
        opt_data.VolumeParams.DirInfoTimeoutValid = 1;
    if (opt_data.set_EaTimeout)
        opt_data.VolumeParams.EaTimeoutValid = 1;
    if (opt_data.set_VolumeInfoTimeout)
        opt_data.VolumeParams.VolumeInfoTimeoutValid = 1;
    if (opt_data.set_KeepFileCache)
        opt_data.VolumeParams.FlushAndPurgeOnCleanup = FALSE;
    opt_data.VolumeParams.CaseSensitiveSearch = TRUE;
    opt_data.VolumeParams.CasePreservedNames = TRUE;
    opt_data.VolumeParams.PersistentAcls = TRUE;
    opt_data.VolumeParams.ReparsePoints = TRUE;
    opt_data.VolumeParams.ReparsePointsAccessCheck = FALSE;
    opt_data.VolumeParams.NamedStreams = FALSE;
    opt_data.VolumeParams.ReadOnlyVolume = FALSE;
    opt_data.VolumeParams.PostCleanupWhenModifiedOnly = TRUE;
    opt_data.VolumeParams.PassQueryDirectoryFileName = TRUE;
    opt_data.VolumeParams.DeviceControl = TRUE;
#if defined(FSP_CFG_REJECT_EARLY_IRP)
    opt_data.VolumeParams.RejectIrpPriorToTransact0 = TRUE;
#endif
    opt_data.VolumeParams.UmFileContextIsUserContext2 = TRUE;
    if (L'\0' == opt_data.VolumeParams.FileSystemName[0])
        memcpy(opt_data.VolumeParams.FileSystemName, L"FUSE", 5 * sizeof(WCHAR));

    f = fsp_fuse_obj_alloc(env, sizeof *f);
    if (0 == f)
        goto fail;

    f->env = env;
    f->set_umask = opt_data.set_umask; f->umask = opt_data.umask;
    f->set_create_umask = opt_data.set_create_umask; f->create_umask = opt_data.create_umask;
    f->set_create_file_umask = opt_data.set_create_file_umask; f->create_file_umask = opt_data.create_file_umask;
    f->set_create_dir_umask = opt_data.set_create_dir_umask; f->create_dir_umask = opt_data.create_dir_umask;
    f->set_uid = opt_data.set_uid; f->uid = opt_data.uid;
    f->set_gid = opt_data.set_gid; f->gid = opt_data.gid;
    f->rellinks = opt_data.rellinks;
    f->dothidden = opt_data.dothidden;
    f->ThreadCount = opt_data.ThreadCount;
    memcpy(&f->ops, ops, opsize);
    f->data = data;
    f->DebugLog = opt_data.debug ? -1 : 0;
    memcpy(&f->VolumeParams, &opt_data.VolumeParams, sizeof opt_data.VolumeParams);
    f->VolumeLabelLength = opt_data.VolumeLabelLength;
    memcpy(&f->VolumeLabel, &opt_data.VolumeLabel, opt_data.VolumeLabelLength);

    Size = (lstrlenW(ch->MountPoint) + 1) * sizeof(WCHAR);
    f->MountPoint = fsp_fuse_obj_alloc(env, Size);
    if (0 == f->MountPoint)
        goto fail;
    memcpy(f->MountPoint, ch->MountPoint, Size);

    Result = FspFileSystemPreflight(
        f->VolumeParams.Prefix[0] ? L"" FSP_FSCTL_NET_DEVICE_NAME : L"" FSP_FSCTL_DISK_DEVICE_NAME,
        '*' != f->MountPoint[0] || '\0' != f->MountPoint[1] ? f->MountPoint : 0);
    if (!NT_SUCCESS(Result))
    {
        switch (Result)
        {
        case STATUS_ACCESS_DENIED:
            ErrorMessage = L": access denied.";
            break;

        case STATUS_NO_SUCH_DEVICE:
            ErrorMessage = L": FSD not found.";
            break;

        case STATUS_OBJECT_NAME_INVALID:
            ErrorMessage = L": invalid mount point.";
            break;

        case STATUS_OBJECT_NAME_COLLISION:
            ErrorMessage = L": mount point in use.";
            break;

        default:
            ErrorMessage = L": unspecified error.";
            break;
        }

        goto fail;
    }

    return f;

fail:
    FspServiceLog(EVENTLOG_ERROR_TYPE,
        L"Cannot create " FSP_FUSE_LIBRARY_NAME " file system%s",
        ErrorMessage);

    if (0 != f)
        fsp_fuse_destroy(env, f);

    return 0;
}

FSP_FUSE_API void fsp_fuse_destroy(struct fsp_fuse_env *env,
    struct fuse *f)
{
    fsp_fuse_obj_free(f->MountPoint);

    fsp_fuse_obj_free(f);
}

FSP_FUSE_API void fsp_fuse_exit(struct fsp_fuse_env *env,
    struct fuse *f)
{
    if (0 != f->LoopEvent)
        SetEvent(f->LoopEvent);
    f->exited = 1;
}

FSP_FUSE_API int FSP_FUSE_API_NAME(fsp_fuse_exited)(struct fsp_fuse_env *env,
    struct fuse *f)
{
    return f->exited;
}

FSP_FUSE_API struct fuse_context *fsp_fuse_get_context(struct fsp_fuse_env *env)
{
    struct fuse_context *context;

    InitOnceExecuteOnce(&fsp_fuse_initonce, fsp_fuse_initialize, 0, 0);
    if (TLS_OUT_OF_INDEXES == fsp_fuse_tlskey)
        return 0;

    context = TlsGetValue(fsp_fuse_tlskey);
    if (0 == context)
    {
        struct fsp_fuse_context_header *contexthdr;

        contexthdr = fsp_fuse_obj_alloc(env,
            sizeof(struct fsp_fuse_context_header) + sizeof(struct fuse_context));
        if (0 == contexthdr)
            return 0;

        context = FSP_FUSE_CONTEXT_FROM_HDR(contexthdr);

        TlsSetValue(fsp_fuse_tlskey, context);
    }

    return context;
}

FSP_FUSE_API int32_t fsp_fuse_ntstatus_from_errno(struct fsp_fuse_env *env,
    int err)
{
    if (0 > err)
        err = -err;

    if ('C' == env->environment)
        switch (err)
        {
        #undef FSP_FUSE_ERRNO
        #define FSP_FUSE_ERRNO 67
        #include "errno.i"
        default:
            return STATUS_ACCESS_DENIED;
        }
    else
        switch (err)
        {
        #undef FSP_FUSE_ERRNO
        #define FSP_FUSE_ERRNO 87
        #include "errno.i"
        default:
            return STATUS_ACCESS_DENIED;
        }
}