[wimlib] / src / win32_apply.c

/*
 * win32_apply.c - Windows-specific code for applying files from a WIM image.
 */

/*
 * Copyright (C) 2013, 2014 Eric Biggers
 *
 * This file is part of wimlib, a library for working with WIM files.
 *
 * wimlib is free software; you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your option)
 * any later version.
 *
 * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with wimlib; if not, see http://www.gnu.org/licenses/.
 */

#ifdef __WIN32__

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include "wimlib/win32_common.h"

#include "wimlib/apply.h"
#include "wimlib/capture.h" /* for mangle_pat() and match_pattern_list()  */
#include "wimlib/dentry.h"
#include "wimlib/error.h"
#include "wimlib/lookup_table.h"
#include "wimlib/metadata.h"
#include "wimlib/reparse.h"
#include "wimlib/textfile.h"
#include "wimlib/xml.h"
#include "wimlib/wimboot.h"

struct win32_apply_ctx {

        /* Extract flags, the pointer to the WIMStruct, etc.  */
        struct apply_ctx common;

        /* WIMBoot information, only filled in if WIMLIB_EXTRACT_FLAG_WIMBOOT
         * was provided  */
        struct {
                u64 data_source_id;
                struct string_set *prepopulate_pats;
                void *mem_prepopulate_pats;
                u8 wim_lookup_table_hash[SHA1_HASH_SIZE];
                bool wof_running;
        } wimboot;

        /* Open handle to the target directory  */
        HANDLE h_target;

        /* NT namespace path to the target directory (buffer allocated)  */
        UNICODE_STRING target_ntpath;

        /* Temporary buffer for building paths (buffer allocated)  */
        UNICODE_STRING pathbuf;

        /* Object attributes to reuse for opening files in the target directory.
         * (attr.ObjectName == &pathbuf) and (attr.RootDirectory == h_target).
         */
        OBJECT_ATTRIBUTES attr;

        /* Temporary I/O status block for system calls  */
        IO_STATUS_BLOCK iosb;

        /* Allocated buffer for creating "printable" paths from our
         * target-relative NT paths  */
        wchar_t *print_buffer;

        /* Allocated buffer for reading stream data when it cannot be extracted
         * directly  */
        u8 *data_buffer;

        /* Pointer to the next byte in @data_buffer to fill  */
        u8 *data_buffer_ptr;

        /* Size allocated in @data_buffer  */
        size_t data_buffer_size;

        /* Current offset in the raw encrypted file being written  */
        size_t encrypted_offset;

        /* Current size of the raw encrypted file being written  */
        size_t encrypted_size;

        /* Temporary buffer for reparse data  */
        struct reparse_buffer_disk rpbuf;

        /* Temporary buffer for reparse data of "fixed" absolute symbolic links
         * and junctions  */
        struct reparse_buffer_disk rpfixbuf;

        /* Array of open handles to filesystem streams currently being written
         */
        HANDLE open_handles[MAX_OPEN_STREAMS];

        /* Number of handles in @open_handles currently open (filled in from the
         * beginning of the array)  */
        unsigned num_open_handles;

        /* List of dentries, joined by @tmp_list, that need to have reparse data
         * extracted as soon as the whole stream has been read into
         * @data_buffer.  */
        struct list_head reparse_dentries;

        /* List of dentries, joined by @tmp_list, that need to have raw
         * encrypted data extracted as soon as the whole stream has been read
         * into @data_buffer.  */
        struct list_head encrypted_dentries;

        /* Number of files for which we didn't have permission to set the full
         * security descriptor.  */
        unsigned long partial_security_descriptors;

        /* Number of files for which we didn't have permission to set any part
         * of the security descriptor.  */
        unsigned long no_security_descriptors;
};

/* Get the drive letter from a Windows path, or return the null character if the
 * path is relative.  */
static wchar_t
get_drive_letter(const wchar_t *path)
{
        /* Skip \\?\ prefix  */
        if (!wcsncmp(path, L"\\\\?\\", 4))
                path += 4;

        /* Return drive letter if valid  */
        if (((path[0] >= L'a' && path[0] <= L'z') ||
             (path[0] >= L'A' && path[0] <= L'Z')) && path[1] == L':')
                return path[0];

        return L'\0';
}

static void
get_vol_flags(const wchar_t *target, DWORD *vol_flags_ret,
              bool *short_names_supported_ret)
{
        wchar_t filesystem_name[MAX_PATH + 1];
        wchar_t drive[4];
        wchar_t *volume = NULL;

        *vol_flags_ret = 0;
        *short_names_supported_ret = false;

        drive[0] = get_drive_letter(target);
        if (drive[0]) {
                drive[1] = L':';
                drive[2] = L'\\';
                drive[3] = L'\0';
                volume = drive;
        }

        if (!GetVolumeInformation(volume, NULL, 0, NULL, NULL,
                                  vol_flags_ret, filesystem_name,
                                  ARRAY_LEN(filesystem_name)))
        {
                DWORD err = GetLastError();
                set_errno_from_win32_error(err);
                WARNING_WITH_ERRNO("Failed to get volume information for "
                                   "\"%ls\" (err=%"PRIu32")",
                                   target, (u32)err);
                return;
        }

        if (wcsstr(filesystem_name, L"NTFS")) {
                /* FILE_SUPPORTS_HARD_LINKS is only supported on Windows 7 and
                 * later.  Force it on anyway if filesystem is NTFS.  */
                *vol_flags_ret |= FILE_SUPPORTS_HARD_LINKS;

                /* There's no volume flag for short names, but according to the
                 * MS documentation they are only user-settable on NTFS.  */
                *short_names_supported_ret = true;
        }
}

static int
win32_get_supported_features(const wchar_t *target,
                             struct wim_features *supported_features)
{
        DWORD vol_flags;
        bool short_names_supported;

        /* Query the features of the target volume.  */

        get_vol_flags(target, &vol_flags, &short_names_supported);

        supported_features->archive_files = 1;
        supported_features->hidden_files = 1;
        supported_features->system_files = 1;

        if (vol_flags & FILE_FILE_COMPRESSION)
                supported_features->compressed_files = 1;

        if (vol_flags & FILE_SUPPORTS_ENCRYPTION) {
                supported_features->encrypted_files = 1;
                supported_features->encrypted_directories = 1;
        }

        supported_features->not_context_indexed_files = 1;

        /* Don't do anything with FILE_SUPPORTS_SPARSE_FILES.  */

        if (vol_flags & FILE_NAMED_STREAMS)
                supported_features->named_data_streams = 1;

        if (vol_flags & FILE_SUPPORTS_HARD_LINKS)
                supported_features->hard_links = 1;

        if (vol_flags & FILE_SUPPORTS_REPARSE_POINTS)
                supported_features->reparse_points = 1;

        if (vol_flags & FILE_PERSISTENT_ACLS)
                supported_features->security_descriptors = 1;

        if (short_names_supported)
                supported_features->short_names = 1;

        supported_features->timestamps = 1;

        /* Note: Windows does not support case sensitive filenames!  At least
         * not without changing the registry and rebooting...  */

        return 0;
}

/* Load the patterns from [PrepopulateList] of WimBootCompress.ini in the WIM
 * image being extracted.  */
static int
load_prepopulate_pats(struct win32_apply_ctx *ctx)
{
        const wchar_t *path = L"\\Windows\\System32\\WimBootCompress.ini";
        struct wim_dentry *dentry;
        struct wim_lookup_table_entry *lte;
        int ret;
        void *buf;
        struct string_set *s;
        void *mem;
        struct text_file_section sec;

        dentry = get_dentry(ctx->common.wim, path, WIMLIB_CASE_INSENSITIVE);
        if (!dentry ||
            (dentry->d_inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
                                              FILE_ATTRIBUTE_REPARSE_POINT |
                                              FILE_ATTRIBUTE_ENCRYPTED)) ||
            !(lte = inode_unnamed_lte(dentry->d_inode, ctx->common.wim->lookup_table)))
        {
                WARNING("%ls does not exist in WIM image!", path);
                return WIMLIB_ERR_PATH_DOES_NOT_EXIST;
        }

        ret = read_full_stream_into_alloc_buf(lte, &buf);
        if (ret)
                return ret;

        s = CALLOC(1, sizeof(struct string_set));
        if (!s) {
                FREE(buf);
                return WIMLIB_ERR_NOMEM;
        }

        sec.name = T("PrepopulateList");
        sec.strings = s;

        ret = do_load_text_file(path, buf, lte->size, &mem, &sec, 1,
                                LOAD_TEXT_FILE_REMOVE_QUOTES |
                                        LOAD_TEXT_FILE_NO_WARNINGS,
                                mangle_pat);
        BUILD_BUG_ON(OS_PREFERRED_PATH_SEPARATOR != WIM_PATH_SEPARATOR);
        FREE(buf);
        if (ret) {
                FREE(s);
                return ret;
        }
        ctx->wimboot.prepopulate_pats = s;
        ctx->wimboot.mem_prepopulate_pats = mem;
        return 0;
}

/* Returns %true if the path to @dentry matches a pattern in [PrepopulateList]
 * of WimBootCompress.ini.  Otherwise returns %false.
 *
 * @dentry must have had its full path calculated.  */
static bool
in_prepopulate_list(struct wim_dentry *dentry,
                    const struct win32_apply_ctx *ctx)
{
        const struct string_set *pats = ctx->wimboot.prepopulate_pats;

        if (!pats || !pats->num_strings)
                return false;

        return match_pattern_list(dentry->_full_path,
                                  wcslen(dentry->_full_path), pats);
}

/* Calculates the SHA-1 message digest of the WIM's lookup table.  */
static int
hash_lookup_table(WIMStruct *wim, u8 hash[SHA1_HASH_SIZE])
{
        return wim_reshdr_to_hash(&wim->hdr.lookup_table_reshdr, wim, hash);
}

/* Prepare for doing a "WIMBoot" extraction by loading patterns from
 * [PrepopulateList] of WimBootCompress.ini and allocating a WOF data source ID
 * on the target volume.  */
static int
start_wimboot_extraction(struct win32_apply_ctx *ctx)
{
        int ret;
        WIMStruct *wim = ctx->common.wim;

        ret = load_prepopulate_pats(ctx);
        if (ret == WIMLIB_ERR_NOMEM)
                return ret;

        if (!wim_info_get_wimboot(wim->wim_info, wim->current_image))
                WARNING("Image is not marked as WIMBoot compatible!");

        ret = hash_lookup_table(ctx->common.wim,
                                ctx->wimboot.wim_lookup_table_hash);
        if (ret)
                return ret;

        return wimboot_alloc_data_source_id(wim->filename,
                                            wim->hdr.guid,
                                            wim->current_image,
                                            ctx->common.target,
                                            &ctx->wimboot.data_source_id,
                                            &ctx->wimboot.wof_running);
}

/* Returns the number of wide characters needed to represent the path to the
 * specified @dentry, relative to the target directory, when extracted.
 *
 * Does not include null terminator (not needed for NtCreateFile).  */
static size_t
dentry_extraction_path_length(const struct wim_dentry *dentry)
{
        size_t len = 0;
        const struct wim_dentry *d;

        d = dentry;
        do {
                len += d->d_extraction_name_nchars + 1;
                d = d->d_parent;
        } while (!dentry_is_root(d) && will_extract_dentry(d));

        return --len;  /* No leading slash  */
}

/* Returns the length of the longest string that might need to be appended to
 * the path to an alias of an inode to open or create a named data stream.
 *
 * If the inode has no named data streams, this will be 0.  Otherwise, this will
 * be 1 plus the length of the longest-named data stream, since the data stream
 * name must be separated from the path by the ':' character.  */
static size_t
inode_longest_named_data_stream_spec(const struct wim_inode *inode)
{
        size_t max = 0;
        for (u16 i = 0; i < inode->i_num_ads; i++) {
                size_t len = inode->i_ads_entries[i].stream_name_nbytes;
                if (len > max)
                        max = len;
        }
        if (max)
                max = 1 + (max / sizeof(wchar_t));
        return max;
}

/* Find the length, in wide characters, of the longest path needed for
 * extraction of any file in @dentry_list relative to the target directory.
 *
 * Accounts for named data streams, but does not include null terminator (not
 * needed for NtCreateFile).  */
static size_t
compute_path_max(struct list_head *dentry_list)
{
        size_t max = 0;
        const struct wim_dentry *dentry;

        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
                size_t len;

                len = dentry_extraction_path_length(dentry);

                /* Account for named data streams  */
                len += inode_longest_named_data_stream_spec(dentry->d_inode);

                if (len > max)
                        max = len;
        }

        return max;
}

/* Build the path at which to extract the @dentry, relative to the target
 * directory.
 *
 * The path is saved in ctx->pathbuf.  */
static void
build_extraction_path(const struct wim_dentry *dentry,
                      struct win32_apply_ctx *ctx)
{
        size_t len;
        wchar_t *p;
        const struct wim_dentry *d;

        len = dentry_extraction_path_length(dentry);

        ctx->pathbuf.Length = len * sizeof(wchar_t);
        p = ctx->pathbuf.Buffer + len;
        for (d = dentry;
             !dentry_is_root(d->d_parent) && will_extract_dentry(d->d_parent);
             d = d->d_parent)
        {
                p -= d->d_extraction_name_nchars;
                wmemcpy(p, d->d_extraction_name, d->d_extraction_name_nchars);
                *--p = '\\';
        }
        /* No leading slash  */
        p -= d->d_extraction_name_nchars;
        wmemcpy(p, d->d_extraction_name, d->d_extraction_name_nchars);
}

/* Build the path at which to extract the @dentry, relative to the target
 * directory, adding the suffix for a named data stream.
 *
 * The path is saved in ctx->pathbuf.  */
static void
build_extraction_path_with_ads(const struct wim_dentry *dentry,
                               struct win32_apply_ctx *ctx,
                               const wchar_t *stream_name,
                               size_t stream_name_nchars)
{
        wchar_t *p;

        build_extraction_path(dentry, ctx);

        /* Add :NAME for named data stream  */
        p = ctx->pathbuf.Buffer + (ctx->pathbuf.Length / sizeof(wchar_t));
        *p++ = L':';
        wmemcpy(p, stream_name, stream_name_nchars);
        ctx->pathbuf.Length += (1 + stream_name_nchars) * sizeof(wchar_t);
}

/* Build the Win32 namespace path to the specified @dentry when extracted.
 *
 * The path is saved in ctx->pathbuf and will be null terminated.
 *
 * XXX: We could get rid of this if it wasn't needed for the file encryption
 * APIs.  */
static void
build_win32_extraction_path(const struct wim_dentry *dentry,
                            struct win32_apply_ctx *ctx)
{
        build_extraction_path(dentry, ctx);

        /* Prepend target_ntpath to our relative path, then change \??\ into \\?\  */

        memmove(ctx->pathbuf.Buffer +
                        (ctx->target_ntpath.Length / sizeof(wchar_t)) + 1,
                ctx->pathbuf.Buffer, ctx->pathbuf.Length);
        memcpy(ctx->pathbuf.Buffer, ctx->target_ntpath.Buffer,
                ctx->target_ntpath.Length);
        ctx->pathbuf.Buffer[ctx->target_ntpath.Length / sizeof(wchar_t)] = L'\\';
        ctx->pathbuf.Length += ctx->target_ntpath.Length + sizeof(wchar_t);
        ctx->pathbuf.Buffer[ctx->pathbuf.Length / sizeof(wchar_t)] = L'\0';

        wimlib_assert(ctx->pathbuf.Length >= 4 * sizeof(wchar_t) &&
                      !wmemcmp(ctx->pathbuf.Buffer, L"\\??\\", 4));

        ctx->pathbuf.Buffer[1] = L'\\';

}

/* Returns a "printable" representation of the last relative NT path that was
 * constructed with build_extraction_path() or build_extraction_path_with_ads().
 *
 * This will be overwritten by the next call to this function.  */
static const wchar_t *
current_path(struct win32_apply_ctx *ctx)
{
        wchar_t *p = ctx->print_buffer;

        p = wmempcpy(p, ctx->common.target, ctx->common.target_nchars);
        *p++ = L'\\';
        p = wmempcpy(p, ctx->pathbuf.Buffer, ctx->pathbuf.Length / sizeof(wchar_t));
        *p = L'\0';
        return ctx->print_buffer;
}

/*
 * Ensures the target directory exists and opens a handle to it, in preparation
 * of using paths relative to it.
 */
static int
prepare_target(struct list_head *dentry_list, struct win32_apply_ctx *ctx)
{
        int ret;
        NTSTATUS status;
        size_t path_max;

        /* Open handle to the target directory (possibly creating it).  */

        ret = win32_path_to_nt_path(ctx->common.target, &ctx->target_ntpath);
        if (ret)
                return ret;

        ctx->attr.Length = sizeof(ctx->attr);
        ctx->attr.ObjectName = &ctx->target_ntpath;

        status = (*func_NtCreateFile)(&ctx->h_target,
                                      FILE_TRAVERSE,
                                      &ctx->attr,
                                      &ctx->iosb,
                                      NULL,
                                      0,
                                      FILE_SHARE_VALID_FLAGS,
                                      FILE_OPEN_IF,
                                      FILE_DIRECTORY_FILE |
                                              FILE_OPEN_REPARSE_POINT |
                                              FILE_OPEN_FOR_BACKUP_INTENT,
                                      NULL,
                                      0);

        if (!NT_SUCCESS(status)) {
                set_errno_from_nt_status(status);
                ERROR_WITH_ERRNO("Can't open or create directory \"%ls\" "
                                 "(status=0x%08"PRIx32")",
                                 ctx->common.target, (u32)status);
                return WIMLIB_ERR_OPENDIR;
        }

        path_max = compute_path_max(dentry_list);

        /* Add some extra for building Win32 paths for the file encryption APIs
         * ...  */
        path_max += 2 + (ctx->target_ntpath.Length / sizeof(wchar_t));

        ctx->pathbuf.MaximumLength = path_max * sizeof(wchar_t);
        ctx->pathbuf.Buffer = MALLOC(ctx->pathbuf.MaximumLength);
        if (!ctx->pathbuf.Buffer)
                return WIMLIB_ERR_NOMEM;

        ctx->attr.RootDirectory = ctx->h_target;
        ctx->attr.ObjectName = &ctx->pathbuf;

        ctx->print_buffer = MALLOC((ctx->common.target_nchars + 1 + path_max + 1) *
                                   sizeof(wchar_t));
        if (!ctx->print_buffer)
                return WIMLIB_ERR_NOMEM;

        return 0;
}

/* When creating an inode that will have a short (DOS) name, we create it using
 * the long name associated with the short name.  This ensures that the short
 * name gets associated with the correct long name.  */
static const struct wim_dentry *
first_extraction_alias(const struct wim_inode *inode)
{
        const struct list_head *next = inode->i_extraction_aliases.next;
        const struct wim_dentry *dentry;

        do {
                dentry = list_entry(next, struct wim_dentry,
                                    d_extraction_alias_node);
                if (dentry_has_short_name(dentry))
                        break;
                next = next->next;
        } while (next != &inode->i_extraction_aliases);
        return dentry;
}

/*
 * Set or clear FILE_ATTRIBUTE_COMPRESSED if the inherited value is different
 * from the desired value.
 *
 * Note that you can NOT override the inherited value of
 * FILE_ATTRIBUTE_COMPRESSED directly with NtCreateFile().
 */
static int
adjust_compression_attribute(HANDLE h, const struct wim_dentry *dentry,
                             struct win32_apply_ctx *ctx)
{
        const bool compressed = (dentry->d_inode->i_attributes &
                                 FILE_ATTRIBUTE_COMPRESSED);

        if (ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ATTRIBUTES)
                return 0;

        if (!ctx->common.supported_features.compressed_files)
                return 0;

        FILE_BASIC_INFORMATION info;
        NTSTATUS status;
        USHORT compression_state;

        /* Get current attributes  */
        status = (*func_NtQueryInformationFile)(h, &ctx->iosb,
                                                &info, sizeof(info),
                                                FileBasicInformation);
        if (NT_SUCCESS(status) &&
            compressed == !!(info.FileAttributes & FILE_ATTRIBUTE_COMPRESSED))
        {
                /* Nothing needs to be done.  */
                return 0;
        }

        /* Set the new compression state  */

        if (compressed)
                compression_state = COMPRESSION_FORMAT_DEFAULT;
        else
                compression_state = COMPRESSION_FORMAT_NONE;

        status = (*func_NtFsControlFile)(h,
                                         NULL,
                                         NULL,
                                         NULL,
                                         &ctx->iosb,
                                         FSCTL_SET_COMPRESSION,
                                         &compression_state,
                                         sizeof(USHORT),
                                         NULL,
                                         0);
        if (NT_SUCCESS(status))
                return 0;

        set_errno_from_nt_status(status);
        ERROR_WITH_ERRNO("Can't %s compression attribute on \"%ls\" "
                         "(status=0x%08"PRIx32")",
                         (compressed ? "set" : "clear"),
                         current_path(ctx), status);
        return WIMLIB_ERR_SET_ATTRIBUTES;
}

/*
 * Clear FILE_ATTRIBUTE_ENCRYPTED if the file or directory is not supposed to be
 * encrypted.
 *
 * You can provide FILE_ATTRIBUTE_ENCRYPTED to NtCreateFile() to set it on the
 * created file.  However, the file or directory will otherwise default to the
 * encryption state of the parent directory.  This function works around this
 * limitation by using DecryptFile() to remove FILE_ATTRIBUTE_ENCRYPTED on files
 * (and directories) that are not supposed to have it set.
 *
 * Regardless of whether it succeeds or fails, this function may close the
 * handle to the file.  If it does, it sets it to NULL.
 */
static int
maybe_clear_encryption_attribute(HANDLE *h_ptr, const struct wim_dentry *dentry,
                                 struct win32_apply_ctx *ctx)
{
        if (dentry->d_inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)
                return 0;

        if (ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ATTRIBUTES)
                return 0;

        if (!ctx->common.supported_features.encrypted_files)
                return 0;

        FILE_BASIC_INFORMATION info;
        NTSTATUS status;
        BOOL bret;

        /* Get current attributes  */
        status = (*func_NtQueryInformationFile)(*h_ptr, &ctx->iosb,
                                                &info, sizeof(info),
                                                FileBasicInformation);
        if (NT_SUCCESS(status) &&
            !(info.FileAttributes & FILE_ATTRIBUTE_ENCRYPTED))
        {
                /* Nothing needs to be done.  */
                return 0;
        }

        /* Set the new encryption state  */

        /* Due to Windows' crappy file encryption APIs, we need to close the
         * handle to the file so we don't get ERROR_SHARING_VIOLATION.  We also
         * hack together a Win32 path, although we will use the \\?\ prefix so
         * it will actually be a NT path in disguise...  */
        (*func_NtClose)(*h_ptr);
        *h_ptr = NULL;

        build_win32_extraction_path(dentry, ctx);

        bret = DecryptFile(ctx->pathbuf.Buffer, 0);

        /* Restore the NT namespace path  */
        build_extraction_path(dentry, ctx);

        if (!bret) {
                DWORD err = GetLastError();
                set_errno_from_win32_error(err);
                ERROR_WITH_ERRNO("Can't decrypt file \"%ls\" (err=%"PRIu32")",
                                  current_path(ctx), (u32)err);
                return WIMLIB_ERR_SET_ATTRIBUTES;
        }
        return 0;
}

/* Set the short name on the open file @h which has been created at the location
 * indicated by @dentry.
 *
 * Note that this may add, change, or remove the short name.
 *
 * @h must be opened with DELETE access.
 *
 * Returns 0 or WIMLIB_ERR_SET_SHORT_NAME.  The latter only happens in
 * STRICT_SHORT_NAMES mode.
 */
static int
set_short_name(HANDLE h, const struct wim_dentry *dentry,
               struct win32_apply_ctx *ctx)
{
        size_t bufsize = offsetof(FILE_NAME_INFORMATION, FileName) +
                         dentry->short_name_nbytes;
        u8 buf[bufsize] _aligned_attribute(8);
        FILE_NAME_INFORMATION *info = (FILE_NAME_INFORMATION *)buf;
        NTSTATUS status;

        info->FileNameLength = dentry->short_name_nbytes;
        memcpy(info->FileName, dentry->short_name, dentry->short_name_nbytes);

        status = (*func_NtSetInformationFile)(h, &ctx->iosb, info, bufsize,
                                              FileShortNameInformation);
        if (NT_SUCCESS(status))
                return 0;

        /* By default, failure to set short names is not an error (since short
         * names aren't too important anymore...).  */
        if (!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_STRICT_SHORT_NAMES))
                return 0;

        if (status == STATUS_SHORT_NAMES_NOT_ENABLED_ON_VOLUME) {
                if (dentry->short_name_nbytes == 0)
                        return 0;
                ERROR("Can't extract short name when short "
                      "names are not enabled on the volume!");
        } else {
                ERROR("Can't set short name on \"%ls\" (status=0x%08"PRIx32")",
                      current_path(ctx), (u32)status);
        }
        return WIMLIB_ERR_SET_SHORT_NAME;
}

/*
 * A wrapper around NtCreateFile() to make it slightly more usable...
 * This uses the path currently constructed in ctx->pathbuf.
 *
 * Also, we always specify FILE_OPEN_FOR_BACKUP_INTENT and
 * FILE_OPEN_REPARSE_POINT.
 */
static NTSTATUS
do_create_file(PHANDLE FileHandle,
               ACCESS_MASK DesiredAccess,
               PLARGE_INTEGER AllocationSize,
               ULONG FileAttributes,
               ULONG CreateDisposition,
               ULONG CreateOptions,
               struct win32_apply_ctx *ctx)
{
        return (*func_NtCreateFile)(FileHandle,
                                    DesiredAccess,
                                    &ctx->attr,
                                    &ctx->iosb,
                                    AllocationSize,
                                    FileAttributes,
                                    FILE_SHARE_VALID_FLAGS,
                                    CreateDisposition,
                                    CreateOptions |
                                        FILE_OPEN_FOR_BACKUP_INTENT |
                                        FILE_OPEN_REPARSE_POINT,
                                    NULL,
                                    0);
}

/* Like do_create_file(), but builds the extraction path of the @dentry first.
 */
static NTSTATUS
create_file(PHANDLE FileHandle,
            ACCESS_MASK DesiredAccess,
            PLARGE_INTEGER AllocationSize,
            ULONG FileAttributes,
            ULONG CreateDisposition,
            ULONG CreateOptions,
            const struct wim_dentry *dentry,
            struct win32_apply_ctx *ctx)
{
        build_extraction_path(dentry, ctx);
        return do_create_file(FileHandle,
                              DesiredAccess,
                              AllocationSize,
                              FileAttributes,
                              CreateDisposition,
                              CreateOptions,
                              ctx);
}

/* Create empty named data streams.
 *
 * Since these won't have 'struct wim_lookup_table_entry's, they won't show up
 * in the call to extract_stream_list().  Hence the need for the special case.
 */
static int
create_any_empty_ads(const struct wim_dentry *dentry,
                     struct win32_apply_ctx *ctx)
{
        const struct wim_inode *inode = dentry->d_inode;
        LARGE_INTEGER allocation_size;
        bool path_modified = false;
        int ret = 0;

        if (!ctx->common.supported_features.named_data_streams)
                return 0;

        for (u16 i = 0; i < inode->i_num_ads; i++) {
                const struct wim_ads_entry *entry;
                NTSTATUS status;
                HANDLE h;

                entry = &inode->i_ads_entries[i];

                /* Not named?  */
                if (!entry->stream_name_nbytes)
                        continue;

                /* Not empty?  */
                if (entry->lte)
                        continue;

                /* Probably setting the allocation size to 0 has no effect, but
                 * we might as well try.  */
                allocation_size.QuadPart = 0;

                build_extraction_path_with_ads(dentry, ctx,
                                               entry->stream_name,
                                               entry->stream_name_nbytes /
                                                        sizeof(wchar_t));
                path_modified = true;
                status = do_create_file(&h, FILE_WRITE_DATA, &allocation_size,
                                        0, FILE_SUPERSEDE, 0, ctx);
                if (!NT_SUCCESS(status)) {
                        set_errno_from_nt_status(status);
                        ERROR_WITH_ERRNO("Can't create \"%ls\" "
                                         "(status=0x%08"PRIx32")",
                                         current_path(ctx), (u32)status);
                        ret = WIMLIB_ERR_OPEN;
                        break;
                }
                (*func_NtClose)(h);
        }
        /* Restore the path to the dentry itself  */
        if (path_modified)
                build_extraction_path(dentry, ctx);
        return ret;
}

/*
 * Creates the directory named by @dentry, or uses an existing directory at that
 * location.  If necessary, sets the short name and/or fixes compression and
 * encryption attributes.
 *
 * Returns 0, WIMLIB_ERR_MKDIR, or WIMLIB_ERR_SET_SHORT_NAME.
 */
static int
create_directory(const struct wim_dentry *dentry,
                 struct win32_apply_ctx *ctx)
{
        HANDLE h;
        NTSTATUS status;
        int ret;
        ULONG attrib;

        /* Special attributes:
         *
         * Use FILE_ATTRIBUTE_ENCRYPTED if the directory needs to have it set.
         * This doesn't work for FILE_ATTRIBUTE_COMPRESSED (unfortunately).
         *
         * Don't specify FILE_ATTRIBUTE_DIRECTORY; it gets set anyway as a
         * result of the FILE_DIRECTORY_FILE option.  */
        attrib = (dentry->d_inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED);

        /* DELETE is needed for set_short_name().
         * GENERIC_READ and GENERIC_WRITE are needed for
         * adjust_compression_attribute().  */
        status = create_file(&h, GENERIC_READ | GENERIC_WRITE | DELETE, NULL,
                             attrib, FILE_OPEN_IF, FILE_DIRECTORY_FILE,
                             dentry, ctx);
        if (!NT_SUCCESS(status)) {
                set_errno_from_nt_status(status);
                ERROR_WITH_ERRNO("Can't create directory \"%ls\" "
                                 "(status=0x%08"PRIx32")",
                                 current_path(ctx), (u32)status);
                return WIMLIB_ERR_MKDIR;
        }

        ret = set_short_name(h, dentry, ctx);

        if (!ret)
                ret = adjust_compression_attribute(h, dentry, ctx);

        if (!ret)
                ret = maybe_clear_encryption_attribute(&h, dentry, ctx);
                /* May close the handle!!! */

        if (h)
                (*func_NtClose)(h);
        return ret;
}

/*
 * Create all the directories being extracted, other than the target directory
 * itself.
 *
 * Note: we don't honor directory hard links.  However, we don't allow them to
 * exist in WIM images anyway (see inode_fixup.c).
 */
static int
create_directories(struct list_head *dentry_list,
                   struct win32_apply_ctx *ctx)
{
        const struct wim_dentry *dentry;
        int ret;

        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {

                if (!(dentry->d_inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY))
                        continue;

                /* Note: Here we include files with
                 * FILE_ATTRIBUTE_DIRECTORY|FILE_ATTRIBUTE_REPARSE_POINT, but we
                 * wait until later to actually set the reparse data.  */

                /* If the root dentry is being extracted, it was already done so
                 * in prepare_target().  */
                if (dentry_is_root(dentry))
                        continue;

                ret = create_directory(dentry, ctx);
                if (ret)
                        return ret;

                ret = create_any_empty_ads(dentry, ctx);
                if (ret)
                        return ret;
        }
        return 0;
}

/*
 * Creates the nondirectory file named by @dentry.
 *
 * On success, returns an open handle to the file in @h_ret, with GENERIC_READ,
 * GENERIC_WRITE, and DELETE access.  Also, the path to the file will be saved
 * in ctx->pathbuf.  On failure, returns WIMLIB_ERR_OPEN.
 */
static int
create_nondirectory_inode(HANDLE *h_ret, const struct wim_dentry *dentry,
                          struct win32_apply_ctx *ctx)
{
        const struct wim_inode *inode;
        ULONG attrib;
        NTSTATUS status;
        bool retried = false;

        inode = dentry->d_inode;

        /* If the file already exists and has FILE_ATTRIBUTE_SYSTEM and/or
         * FILE_ATTRIBUTE_HIDDEN, these must be specified in order to supersede
         * the file.
         *
         * Normally the user shouldn't be trying to overwrite such files anyway,
         * but we at least provide FILE_ATTRIBUTE_SYSTEM and
         * FILE_ATTRIBUTE_HIDDEN if the WIM inode has those attributes so that
         * we catch the case where the user extracts the same files to the same
         * location more than one time.
         *
         * Also specify FILE_ATTRIBUTE_ENCRYPTED if the file needs to be
         * encrypted.
         *
         * In NO_ATTRIBUTES mode just don't specify any attributes at all.
         */
        if (ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ATTRIBUTES) {
                attrib = 0;
        } else {
                attrib = (inode->i_attributes & (FILE_ATTRIBUTE_SYSTEM |
                                                 FILE_ATTRIBUTE_HIDDEN |
                                                 FILE_ATTRIBUTE_ENCRYPTED));
        }
        build_extraction_path(dentry, ctx);
retry:
        status = do_create_file(h_ret, GENERIC_READ | GENERIC_WRITE | DELETE,
                                NULL, attrib, FILE_SUPERSEDE,
                                FILE_NON_DIRECTORY_FILE, ctx);
        if (NT_SUCCESS(status)) {
                int ret;

                ret = adjust_compression_attribute(*h_ret, dentry, ctx);
                if (ret) {
                        (*func_NtClose)(*h_ret);
                        return ret;
                }

                ret = maybe_clear_encryption_attribute(h_ret, dentry, ctx);
                /* May close the handle!!! */

                if (ret) {
                        if (*h_ret)
                                (*func_NtClose)(*h_ret);
                        return ret;
                }

                if (!*h_ret) {
                        /* Re-open the handle so that we can return it on
                         * success.  */
                        status = do_create_file(h_ret,
                                                GENERIC_READ |
                                                        GENERIC_WRITE | DELETE,
                                                NULL, 0, FILE_OPEN,
                                                FILE_NON_DIRECTORY_FILE, ctx);
                        if (!NT_SUCCESS(status))
                                goto fail;
                }

                ret = create_any_empty_ads(dentry, ctx);
                if (ret) {
                        (*func_NtClose)(*h_ret);
                        return ret;
                }
                return 0;
        }

        if (status == STATUS_ACCESS_DENIED && !retried) {
                /* We also can't supersede an existing file that has
                 * FILE_ATTRIBUTE_READONLY set; doing so causes NtCreateFile()
                 * to return STATUS_ACCESS_DENIED .  The only workaround seems
                 * to be to explicitly remove FILE_ATTRIBUTE_READONLY on the
                 * existing file, then try again.  */

                FILE_BASIC_INFORMATION info;
                HANDLE h;

                status = do_create_file(&h, FILE_WRITE_ATTRIBUTES, NULL, 0,
                                        FILE_OPEN, FILE_NON_DIRECTORY_FILE, ctx);
                if (!NT_SUCCESS(status))
                        goto fail;

                memset(&info, 0, sizeof(info));
                info.FileAttributes = FILE_ATTRIBUTE_NORMAL;

                status = (*func_NtSetInformationFile)(h, &ctx->iosb,
                                                      &info, sizeof(info),
                                                      FileBasicInformation);
                (*func_NtClose)(h);
                if (!NT_SUCCESS(status))
                        goto fail;
                retried = true;
                goto retry;
        }
fail:
        set_errno_from_nt_status(status);
        ERROR_WITH_ERRNO("Can't create file \"%ls\" (status=0x%08"PRIx32")",
                         current_path(ctx), (u32)status);
        return WIMLIB_ERR_OPEN;
}

/* Creates a hard link at the location named by @dentry to the file represented
 * by the open handle @h.  Or, if the target volume does not support hard links,
 * create a separate file instead.  */
static int
create_link(HANDLE h, const struct wim_dentry *dentry,
            struct win32_apply_ctx *ctx)
{
        if (ctx->common.supported_features.hard_links) {

                build_extraction_path(dentry, ctx);

                size_t bufsize = offsetof(FILE_LINK_INFORMATION, FileName) +
                                 ctx->pathbuf.Length + sizeof(wchar_t);
                u8 buf[bufsize] _aligned_attribute(8);
                FILE_LINK_INFORMATION *info = (FILE_LINK_INFORMATION *)buf;
                NTSTATUS status;

                info->ReplaceIfExists = TRUE;
                info->RootDirectory = ctx->attr.RootDirectory;
                info->FileNameLength = ctx->pathbuf.Length;
                memcpy(info->FileName, ctx->pathbuf.Buffer, ctx->pathbuf.Length);
                info->FileName[info->FileNameLength / 2] = L'\0';

                /* Note: the null terminator isn't actually necessary,
                 * but if you don't add the extra character, you get
                 * STATUS_INFO_LENGTH_MISMATCH when FileNameLength
                 * happens to be 2  */

                status = (*func_NtSetInformationFile)(h, &ctx->iosb,
                                                      info, bufsize,
                                                      FileLinkInformation);
                if (NT_SUCCESS(status))
                        return 0;
                ERROR("Failed to create link \"%ls\" (status=0x%08"PRIx32")",
                      current_path(ctx), (u32)status);
                return WIMLIB_ERR_LINK;
        } else {
                HANDLE h2;
                int ret;

                ret = create_nondirectory_inode(&h2, dentry, ctx);
                if (ret)
                        return ret;

                (*func_NtClose)(h2);
                return 0;
        }
}

/* Given an inode (represented by the open handle @h) for which one link has
 * been created (named by @first_dentry), create the other links.
 *
 * Or, if the target volume does not support hard links, create separate files.
 *
 * Note: This uses ctx->pathbuf and does not reset it.
 */
static int
create_links(HANDLE h, const struct wim_dentry *first_dentry,
             struct win32_apply_ctx *ctx)
{
        const struct wim_inode *inode;
        const struct list_head *next;
        const struct wim_dentry *dentry;
        int ret;

        inode = first_dentry->d_inode;
        next = inode->i_extraction_aliases.next;
        do {
                dentry = list_entry(next, struct wim_dentry,
                                    d_extraction_alias_node);
                if (dentry != first_dentry) {
                        ret = create_link(h, dentry, ctx);
                        if (ret)
                                return ret;
                }
                next = next->next;
        } while (next != &inode->i_extraction_aliases);
        return 0;
}

/* Create a nondirectory file, including all links.  */
static int
create_nondirectory(const struct wim_inode *inode, struct win32_apply_ctx *ctx)
{
        const struct wim_dentry *first_dentry;
        HANDLE h;
        int ret;

        first_dentry = first_extraction_alias(inode);

        /* Create first link.  */
        ret = create_nondirectory_inode(&h, first_dentry, ctx);
        if (ret)
                return ret;

        /* Set short name.  */
        ret = set_short_name(h, first_dentry, ctx);

        /* Create additional links, OR if hard links are not supported just
         * create more files.  */
        if (!ret)
                ret = create_links(h, first_dentry, ctx);

        (*func_NtClose)(h);
        return ret;
}

/* Create all the nondirectory files being extracted, including all aliases
 * (hard links).  */
static int
create_nondirectories(struct list_head *dentry_list, struct win32_apply_ctx *ctx)
{
        const struct wim_dentry *dentry;
        const struct wim_inode *inode;
        int ret;

        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
                inode = dentry->d_inode;
                if (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY)
                        continue;
                /* Call create_nondirectory() only once per inode  */
                if (dentry != inode_first_extraction_dentry(inode))
                        continue;
                ret = create_nondirectory(inode, ctx);
                if (ret)
                        return ret;
        }
        return 0;
}

static void
close_handles(struct win32_apply_ctx *ctx)
{
        for (unsigned i = 0; i < ctx->num_open_handles; i++)
                (*func_NtClose)(ctx->open_handles[i]);
}

/* Prepare to read the next stream, which has size @stream_size, into an
 * in-memory buffer.  */
static int
prepare_data_buffer(struct win32_apply_ctx *ctx, u64 stream_size)
{
        if (stream_size > ctx->data_buffer_size) {
                /* Larger buffer needed.  */
                void *new_buffer;
                if ((size_t)stream_size != stream_size)
                        return WIMLIB_ERR_NOMEM;
                new_buffer = REALLOC(ctx->data_buffer, stream_size);
                if (!new_buffer)
                        return WIMLIB_ERR_NOMEM;
                ctx->data_buffer = new_buffer;
                ctx->data_buffer_size = stream_size;
        }
        /* On the first call this changes data_buffer_ptr from NULL, which tells
         * extract_chunk() that the data buffer needs to be filled while reading
         * the stream data.  */
        ctx->data_buffer_ptr = ctx->data_buffer;
        return 0;
}

static int
begin_extract_stream_instance(const struct wim_lookup_table_entry *stream,
                              struct wim_dentry *dentry,
                              const wchar_t *stream_name,
                              struct win32_apply_ctx *ctx)
{
        const struct wim_inode *inode = dentry->d_inode;
        size_t stream_name_nchars = 0;
        FILE_ALLOCATION_INFORMATION alloc_info;
        HANDLE h;
        NTSTATUS status;

        if (unlikely(stream_name))
                stream_name_nchars = wcslen(stream_name);

        if (unlikely(stream_name_nchars)) {
                build_extraction_path_with_ads(dentry, ctx,
                                               stream_name, stream_name_nchars);
        } else {
                build_extraction_path(dentry, ctx);
        }

        /* Reparse point?  */
        if (unlikely(inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT)
            && (stream_name_nchars == 0))
        {
                if (!ctx->common.supported_features.reparse_points)
                        return 0;

                /* We can't write the reparse stream directly; we must set it
                 * with FSCTL_SET_REPARSE_POINT, which requires that all the
                 * data be available.  So, stage the data in a buffer.  */

                list_add_tail(&dentry->tmp_list, &ctx->reparse_dentries);
                return prepare_data_buffer(ctx, stream->size);
        }

        /* Encrypted file?  */
        if (unlikely(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)
            && (stream_name_nchars == 0))
        {
                if (!ctx->common.supported_features.encrypted_files)
                        return 0;

                /* We can't write encrypted file streams directly; we must use
                 * WriteEncryptedFileRaw(), which requires providing the data
                 * through a callback function.  This can't easily be combined
                 * with our own callback-based approach.
                 *
                 * The current workaround is to simply read the stream into
                 * memory and write the encrypted file from that.
                 *
                 * TODO: This isn't sufficient for extremely large encrypted
                 * files.  Perhaps we should create an extra thread to write
                 * such files...  */
                list_add_tail(&dentry->tmp_list, &ctx->encrypted_dentries);
                return prepare_data_buffer(ctx, stream->size);
        }

        /* Extracting unnamed data stream in WIMBoot mode?  */
        if (unlikely(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT)
            && (stream_name_nchars == 0)
            && (stream->resource_location == RESOURCE_IN_WIM)
            && (stream->rspec->wim == ctx->common.wim)
            && (stream->size == stream->rspec->uncompressed_size))
        {
                int ret = calculate_dentry_full_path(dentry);
                if (ret)
                        return ret;
                if (in_prepopulate_list(dentry, ctx)) {
                        union wimlib_progress_info info;

                        info.wimboot_exclude.path_in_wim = dentry->_full_path;
                        info.wimboot_exclude.extraction_path = current_path(ctx);

                        ret = call_progress(ctx->common.progfunc,
                                            WIMLIB_PROGRESS_MSG_WIMBOOT_EXCLUDE,
                                            &info, ctx->common.progctx);
                        FREE(dentry->_full_path);
                        dentry->_full_path = NULL;
                        if (ret)
                                return ret;
                        /* Go on and open the file for normal extraction.  */
                } else {
                        FREE(dentry->_full_path);
                        dentry->_full_path = NULL;
                        return wimboot_set_pointer(&ctx->attr,
                                                   current_path(ctx),
                                                   stream,
                                                   ctx->wimboot.data_source_id,
                                                   ctx->wimboot.wim_lookup_table_hash,
                                                   ctx->wimboot.wof_running);
                }
        }

        if (ctx->num_open_handles == MAX_OPEN_STREAMS) {
                /* XXX: Fix this.  But because of the checks in
                 * extract_stream_list(), this can now only happen on a
                 * filesystem that does not support hard links.  */
                ERROR("Can't extract data: too many open files!");
                return WIMLIB_ERR_UNSUPPORTED;
        }

        /* Open a new handle  */
        status = do_create_file(&h,
                                FILE_WRITE_DATA | SYNCHRONIZE,
                                NULL, 0, FILE_OPEN_IF,
                                FILE_SEQUENTIAL_ONLY |
                                        FILE_SYNCHRONOUS_IO_NONALERT,
                                ctx);
        if (!NT_SUCCESS(status)) {
                set_errno_from_nt_status(status);
                ERROR_WITH_ERRNO("Can't open \"%ls\" for writing "
                                 "(status=0x%08"PRIx32")",
                                 current_path(ctx), (u32)status);
                return WIMLIB_ERR_OPEN;
        }

        ctx->open_handles[ctx->num_open_handles++] = h;

        /* Allocate space for the data.  */
        alloc_info.AllocationSize.QuadPart = stream->size;
        (*func_NtSetInformationFile)(h, &ctx->iosb,
                                     &alloc_info, sizeof(alloc_info),
                                     FileAllocationInformation);
        return 0;
}

/* Set the reparse data @rpbuf of length @rpbuflen on the extracted file
 * corresponding to the WIM dentry @dentry.  */
static int
do_set_reparse_data(const struct wim_dentry *dentry,
                    const void *rpbuf, u16 rpbuflen,
                    struct win32_apply_ctx *ctx)
{
        NTSTATUS status;
        HANDLE h;

        status = create_file(&h, GENERIC_WRITE, NULL,
                             0, FILE_OPEN, 0, dentry, ctx);
        if (!NT_SUCCESS(status))
                goto fail;

        status = (*func_NtFsControlFile)(h, NULL, NULL, NULL,
                                         &ctx->iosb, FSCTL_SET_REPARSE_POINT,
                                         (void *)rpbuf, rpbuflen,
                                         NULL, 0);
        (*func_NtClose)(h);

        if (NT_SUCCESS(status))
                return 0;

        /* On Windows, by default only the Administrator can create symbolic
         * links for some reason.  By default we just issue a warning if this
         * appears to be the problem.  Use WIMLIB_EXTRACT_FLAG_STRICT_SYMLINKS
         * to get a hard error.  */
        if (!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_STRICT_SYMLINKS)
            && (status == STATUS_PRIVILEGE_NOT_HELD ||
                status == STATUS_ACCESS_DENIED)
            && (dentry->d_inode->i_reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
                dentry->d_inode->i_reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT))
        {
                WARNING("Can't create symbolic link \"%ls\"!              \n"
                        "          (Need Administrator rights, or at least "
                        "the\n"
                        "          SeCreateSymbolicLink privilege.)",
                        current_path(ctx));
                return 0;
        }

fail:
        set_errno_from_nt_status(status);
        ERROR_WITH_ERRNO("Can't set reparse data on \"%ls\" "
                         "(status=0x%08"PRIx32")",
                         current_path(ctx), (u32)status);
        return WIMLIB_ERR_SET_REPARSE_DATA;
}

/* Given a Windows NT namespace path, such as \??\e:\Windows\System32, return a
 * pointer to the suffix of the path that begins with the device directly, such
 * as e:\Windows\System32.  */
static const wchar_t *
skip_nt_toplevel_component(const wchar_t *path, size_t path_nchars)
{
        static const wchar_t * const dirs[] = {
                L"\\??\\",
                L"\\DosDevices\\",
                L"\\Device\\",
        };
        size_t first_dir_len = 0;
        const wchar_t * const end = path + path_nchars;

        for (size_t i = 0; i < ARRAY_LEN(dirs); i++) {
                size_t len = wcslen(dirs[i]);
                if (len <= (end - path) && !wcsnicmp(path, dirs[i], len)) {
                        first_dir_len = len;
                        break;
                }
        }
        if (first_dir_len == 0)
                return path;
        path += first_dir_len;
        while (path != end && *path == L'\\')
                path++;
        return path;
}

/* Given a Windows NT namespace path, such as \??\e:\Windows\System32, return a
 * pointer to the suffix of the path that is device-relative, such as
 * Windows\System32.
 *
 * The path has an explicit length and is not necessarily null terminated.
 *
 * If the path just something like \??\e: then the returned pointer will point
 * just past the colon.  In this case the length of the result will be 0
 * characters.  */
static const wchar_t *
get_device_relative_path(const wchar_t *path, size_t path_nchars)
{
        const wchar_t * const orig_path = path;
        const wchar_t * const end = path + path_nchars;

        path = skip_nt_toplevel_component(path, path_nchars);
        if (path == orig_path)
                return orig_path;

        path = wmemchr(path, L'\\', (end - path));
        if (!path)
                return end;
        do {
                path++;
        } while (path != end && *path == L'\\');
        return path;
}

/*
 * Given a reparse point buffer for a symbolic link or junction, adjust its
 * contents so that the target of the link is consistent with the new location
 * of the files.
 */
static void
try_rpfix(u8 *rpbuf, u16 *rpbuflen_p, struct win32_apply_ctx *ctx)
{
        struct reparse_data rpdata;
        size_t orig_subst_name_nchars;
        const wchar_t *relpath;
        size_t relpath_nchars;
        size_t target_ntpath_nchars;
        size_t fixed_subst_name_nchars;
        const wchar_t *fixed_print_name;
        size_t fixed_print_name_nchars;

        if (parse_reparse_data(rpbuf, *rpbuflen_p, &rpdata)) {
                /* Do nothing if the reparse data is invalid.  */
                return;
        }

        if (rpdata.rptag == WIM_IO_REPARSE_TAG_SYMLINK &&
            (rpdata.rpflags & SYMBOLIC_LINK_RELATIVE))
        {
                /* Do nothing if it's a relative symbolic link.  */
                return;
        }

        /* Build the new substitute name from the NT namespace path to the
         * target directory, then a path separator, then the "device relative"
         * part of the old substitute name.  */

        orig_subst_name_nchars = rpdata.substitute_name_nbytes / sizeof(wchar_t);

        relpath = get_device_relative_path(rpdata.substitute_name,
                                           orig_subst_name_nchars);
        relpath_nchars = orig_subst_name_nchars -
                         (relpath - rpdata.substitute_name);

        target_ntpath_nchars = ctx->target_ntpath.Length / sizeof(wchar_t);

        fixed_subst_name_nchars = target_ntpath_nchars;
        if (relpath_nchars)
                fixed_subst_name_nchars += 1 + relpath_nchars;
        wchar_t fixed_subst_name[fixed_subst_name_nchars];

        wmemcpy(fixed_subst_name, ctx->target_ntpath.Buffer,
                target_ntpath_nchars);
        if (relpath_nchars) {
                fixed_subst_name[target_ntpath_nchars] = L'\\';
                wmemcpy(&fixed_subst_name[target_ntpath_nchars + 1],
                        relpath, relpath_nchars);
        }
        /* Doesn't need to be null-terminated.  */

        /* Print name should be Win32, but not all NT names can even be
         * translated to Win32 names.  But we can at least delete the top-level
         * directory, such as \??\, and this will have the expected result in
         * the usual case.  */
        fixed_print_name = skip_nt_toplevel_component(fixed_subst_name,
                                                      fixed_subst_name_nchars);
        fixed_print_name_nchars = fixed_subst_name_nchars - (fixed_print_name -
                                                             fixed_subst_name);

        rpdata.substitute_name = fixed_subst_name;
        rpdata.substitute_name_nbytes = fixed_subst_name_nchars * sizeof(wchar_t);
        rpdata.print_name = (wchar_t *)fixed_print_name;
        rpdata.print_name_nbytes = fixed_print_name_nchars * sizeof(wchar_t);
        make_reparse_buffer(&rpdata, rpbuf, rpbuflen_p);
}

/* Sets reparse data on the specified file.  This handles "fixing" the targets
 * of absolute symbolic links and junctions if WIMLIB_EXTRACT_FLAG_RPFIX was
 * specified.  */
static int
set_reparse_data(const struct wim_dentry *dentry,
                 const void *_rpbuf, u16 rpbuflen, struct win32_apply_ctx *ctx)
{
        const struct wim_inode *inode = dentry->d_inode;
        const void *rpbuf = _rpbuf;

        if ((ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_RPFIX)
            && !inode->i_not_rpfixed
            && (inode->i_reparse_tag == WIM_IO_REPARSE_TAG_SYMLINK ||
                inode->i_reparse_tag == WIM_IO_REPARSE_TAG_MOUNT_POINT))
        {
                memcpy(&ctx->rpfixbuf, _rpbuf, rpbuflen);
                try_rpfix((u8 *)&ctx->rpfixbuf, &rpbuflen, ctx);
                rpbuf = &ctx->rpfixbuf;
        }
        return do_set_reparse_data(dentry, rpbuf, rpbuflen, ctx);

}

/* Import the next block of raw encrypted data  */
static DWORD WINAPI
import_encrypted_data(PBYTE pbData, PVOID pvCallbackContext, PULONG Length)
{
        struct win32_apply_ctx *ctx = pvCallbackContext;
        ULONG copy_len;

        copy_len = min(ctx->encrypted_size - ctx->encrypted_offset, *Length);
        memcpy(pbData, &ctx->data_buffer[ctx->encrypted_offset], copy_len);
        ctx->encrypted_offset += copy_len;
        *Length = copy_len;
        return ERROR_SUCCESS;
}

/* Write the raw encrypted data to the already-created file corresponding to
 * @dentry.
 *
 * The raw encrypted data is provided in ctx->data_buffer, and its size is
 * ctx->encrypted_size.  */
static int
extract_encrypted_file(const struct wim_dentry *dentry,
                       struct win32_apply_ctx *ctx)
{
        void *rawctx;
        DWORD err;

        /* Temporarily build a Win32 path for OpenEncryptedFileRaw()  */
        build_win32_extraction_path(dentry, ctx);

        err = OpenEncryptedFileRaw(ctx->pathbuf.Buffer,
                                   CREATE_FOR_IMPORT, &rawctx);

        /* Restore the NT namespace path  */
        build_extraction_path(dentry, ctx);

        if (err != ERROR_SUCCESS) {
                set_errno_from_win32_error(err);
                ERROR_WITH_ERRNO("Can't open \"%ls\" for encrypted import "
                                 "(err=%"PRIu32")", current_path(ctx), (u32)err);
                return WIMLIB_ERR_OPEN;
        }

        ctx->encrypted_offset = 0;

        err = WriteEncryptedFileRaw(import_encrypted_data, ctx, rawctx);

        CloseEncryptedFileRaw(rawctx);

        if (err != ERROR_SUCCESS) {
                set_errno_from_win32_error(err);
                ERROR_WITH_ERRNO("Can't import encrypted file \"%ls\" "
                                 "(err=%"PRIu32")", current_path(ctx), (u32)err);
                return WIMLIB_ERR_WRITE;
        }

        return 0;
}

/* Called when starting to read a stream for extraction on Windows  */
static int
begin_extract_stream(struct wim_lookup_table_entry *stream, void *_ctx)
{
        struct win32_apply_ctx *ctx = _ctx;
        const struct stream_owner *owners = stream_owners(stream);
        int ret;

        ctx->num_open_handles = 0;
        ctx->data_buffer_ptr = NULL;
        INIT_LIST_HEAD(&ctx->reparse_dentries);
        INIT_LIST_HEAD(&ctx->encrypted_dentries);

        for (u32 i = 0; i < stream->out_refcnt; i++) {
                const struct wim_inode *inode = owners[i].inode;
                const wchar_t *stream_name = owners[i].stream_name;
                struct wim_dentry *dentry;

                /* A copy of the stream needs to be extracted to @inode.  */

                if (ctx->common.supported_features.hard_links) {
                        dentry = inode_first_extraction_dentry(inode);
                        ret = begin_extract_stream_instance(stream, dentry,
                                                            stream_name, ctx);
                        if (ret)
                                goto fail;
                } else {
                        /* Hard links not supported.  Extract the stream
                         * separately to each alias of the inode.  */
                        struct list_head *next;

                        next = inode->i_extraction_aliases.next;
                        do {
                                dentry = list_entry(next, struct wim_dentry,
                                                    d_extraction_alias_node);
                                ret = begin_extract_stream_instance(stream,
                                                                    dentry,
                                                                    stream_name,
                                                                    ctx);
                                if (ret)
                                        goto fail;
                                next = next->next;
                        } while (next != &inode->i_extraction_aliases);
                }
        }

        return 0;

fail:
        close_handles(ctx);
        return ret;
}

/* Called when the next chunk of a stream has been read for extraction on
 * Windows  */
static int
extract_chunk(const void *chunk, size_t size, void *_ctx)
{
        struct win32_apply_ctx *ctx = _ctx;

        /* Write the data chunk to each open handle  */
        for (unsigned i = 0; i < ctx->num_open_handles; i++) {
                u8 *bufptr = (u8 *)chunk;
                size_t bytes_remaining = size;
                NTSTATUS status;
                while (bytes_remaining) {
                        ULONG count = min(0xFFFFFFFF, bytes_remaining);

                        status = (*func_NtWriteFile)(ctx->open_handles[i],
                                                     NULL, NULL, NULL,
                                                     &ctx->iosb, bufptr, count,
                                                     NULL, NULL);
                        if (!NT_SUCCESS(status)) {
                                set_errno_from_nt_status(status);
                                ERROR_WITH_ERRNO("Error writing data to target "
                                                 "volume (status=0x%08"PRIx32")",
                                                 (u32)status);
                                return WIMLIB_ERR_WRITE;
                        }
                        bufptr += ctx->iosb.Information;
                        bytes_remaining -= ctx->iosb.Information;
                }
        }

        /* Copy the data chunk into the buffer (if needed)  */
        if (ctx->data_buffer_ptr)
                ctx->data_buffer_ptr = mempcpy(ctx->data_buffer_ptr,
                                               chunk, size);
        return 0;
}

/* Called when a stream has been fully read for extraction on Windows  */
static int
end_extract_stream(struct wim_lookup_table_entry *stream, int status, void *_ctx)
{
        struct win32_apply_ctx *ctx = _ctx;
        int ret;
        const struct wim_dentry *dentry;

        close_handles(ctx);

        if (status)
                return status;

        if (likely(!ctx->data_buffer_ptr))
                return 0;

        if (!list_empty(&ctx->reparse_dentries)) {
                if (stream->size > REPARSE_DATA_MAX_SIZE) {
                        dentry = list_first_entry(&ctx->reparse_dentries,
                                                  struct wim_dentry, tmp_list);
                        build_extraction_path(dentry, ctx);
                        ERROR("Reparse data of \"%ls\" has size "
                              "%"PRIu64" bytes (exceeds %u bytes)",
                              current_path(ctx), stream->size,
                              REPARSE_DATA_MAX_SIZE);
                        return WIMLIB_ERR_INVALID_REPARSE_DATA;
                }
                /* In the WIM format, reparse streams are just the reparse data
                 * and omit the header.  But we can reconstruct the header.  */
                memcpy(ctx->rpbuf.rpdata, ctx->data_buffer, stream->size);
                ctx->rpbuf.rpdatalen = stream->size;
                ctx->rpbuf.rpreserved = 0;
                list_for_each_entry(dentry, &ctx->reparse_dentries, tmp_list) {
                        ctx->rpbuf.rptag = dentry->d_inode->i_reparse_tag;
                        ret = set_reparse_data(dentry, &ctx->rpbuf,
                                               stream->size + REPARSE_DATA_OFFSET,
                                               ctx);
                        if (ret)
                                return ret;
                }
        }

        if (!list_empty(&ctx->encrypted_dentries)) {
                ctx->encrypted_size = stream->size;
                list_for_each_entry(dentry, &ctx->encrypted_dentries, tmp_list) {
                        ret = extract_encrypted_file(dentry, ctx);
                        if (ret)
                                return ret;
                }
        }

        return 0;
}

/* Attributes that can't be set directly  */
#define SPECIAL_ATTRIBUTES                      \
        (FILE_ATTRIBUTE_REPARSE_POINT   |       \
         FILE_ATTRIBUTE_DIRECTORY       |       \
         FILE_ATTRIBUTE_ENCRYPTED       |       \
         FILE_ATTRIBUTE_SPARSE_FILE     |       \
         FILE_ATTRIBUTE_COMPRESSED)

/* Set the security descriptor @desc, of @desc_size bytes, on the file with open
 * handle @h.  */
static NTSTATUS
set_security_descriptor(HANDLE h, const void *desc,
                        size_t desc_size, struct win32_apply_ctx *ctx)
{
        SECURITY_INFORMATION info;
        NTSTATUS status;

        /* We really just want to set entire the security descriptor as-is, but
         * all available APIs require specifying the specific parts of the
         * descriptor being set.  Start out by requesting all parts be set.  If
         * permissions problems are encountered, fall back to omitting some
         * parts (first the SACL, then the DACL, then the owner), unless the
         * WIMLIB_EXTRACT_FLAG_STRICT_ACLS flag has been enabled.  */
        info = OWNER_SECURITY_INFORMATION | GROUP_SECURITY_INFORMATION |
               DACL_SECURITY_INFORMATION | SACL_SECURITY_INFORMATION;

        /* Prefer NtSetSecurityObject() to SetFileSecurity().  SetFileSecurity()
         * itself necessarily uses NtSetSecurityObject() as the latter is the
         * underlying system call for setting security information, but
         * SetFileSecurity() opens the handle with NtCreateFile() without
         * FILE_OPEN_FILE_BACKUP_INTENT.  Hence, access checks are done and due
         * to the Windows security model, even a process running as the
         * Administrator can have access denied.  (Of course, this not mentioned
         * in the MS "documentation".)  */
retry:
        status = (*func_NtSetSecurityObject)(h, info, (PSECURITY_DESCRIPTOR)desc);
        if (NT_SUCCESS(status))
                return status;
        /* Failed to set the requested parts of the security descriptor.  If the
         * error was permissions-related, try to set fewer parts of the security
         * descriptor, unless WIMLIB_EXTRACT_FLAG_STRICT_ACLS is enabled.  */
        if ((status == STATUS_PRIVILEGE_NOT_HELD ||
             status == STATUS_ACCESS_DENIED) &&
            !(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_STRICT_ACLS))
        {
                if (info & SACL_SECURITY_INFORMATION) {
                        info &= ~SACL_SECURITY_INFORMATION;
                        ctx->partial_security_descriptors++;
                        goto retry;
                }
                if (info & DACL_SECURITY_INFORMATION) {
                        info &= ~DACL_SECURITY_INFORMATION;
                        goto retry;
                }
                if (info & OWNER_SECURITY_INFORMATION) {
                        info &= ~OWNER_SECURITY_INFORMATION;
                        goto retry;
                }
                /* Nothing left except GROUP, and if we removed it we
                 * wouldn't have anything at all.  */
        }

        /* No part of the security descriptor could be set, or
         * WIMLIB_EXTRACT_FLAG_STRICT_ACLS is enabled and the full security
         * descriptor could not be set.  */
        if (!(info & SACL_SECURITY_INFORMATION))
                ctx->partial_security_descriptors--;
        ctx->no_security_descriptors++;
        return status;
}

/* Set metadata on the open file @h from the WIM inode @inode.  */
static int
do_apply_metadata_to_file(HANDLE h, const struct wim_inode *inode,
                          struct win32_apply_ctx *ctx)
{
        FILE_BASIC_INFORMATION info;
        NTSTATUS status;

        /* Set security descriptor if present and not in NO_ACLS mode  */
        if (inode->i_security_id >= 0 &&
            !(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ACLS))
        {
                const struct wim_security_data *sd;
                const void *desc;
                size_t desc_size;

                sd = wim_get_current_security_data(ctx->common.wim);
                desc = sd->descriptors[inode->i_security_id];
                desc_size = sd->sizes[inode->i_security_id];

                status = set_security_descriptor(h, desc, desc_size, ctx);
                if (!NT_SUCCESS(status) &&
                    (ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_STRICT_ACLS))
                {
                        set_errno_from_nt_status(status);
                        ERROR_WITH_ERRNO("Can't set security descriptor "
                                         "on \"%ls\" (status=0x%08"PRIx32")",
                                         current_path(ctx), (u32)status);
                        return WIMLIB_ERR_SET_SECURITY;
                }
        }

        /* Set attributes and timestamps  */
        info.CreationTime.QuadPart = inode->i_creation_time;
        info.LastAccessTime.QuadPart = inode->i_last_access_time;
        info.LastWriteTime.QuadPart = inode->i_last_write_time;
        info.ChangeTime.QuadPart = 0;
        if (ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ATTRIBUTES)
                info.FileAttributes = 0;
        else
                info.FileAttributes = inode->i_attributes & ~SPECIAL_ATTRIBUTES;

        status = (*func_NtSetInformationFile)(h, &ctx->iosb,
                                              &info, sizeof(info),
                                              FileBasicInformation);
        /* On FAT volumes we get STATUS_INVALID_PARAMETER if we try to set
         * attributes on the root directory.  (Apparently because FAT doesn't
         * actually have a place to store those attributes!)  */
        if (!NT_SUCCESS(status)
            && !(status == STATUS_INVALID_PARAMETER &&
                 dentry_is_root(inode_first_extraction_dentry(inode))))
        {
                set_errno_from_nt_status(status);
                ERROR_WITH_ERRNO("Can't set basic metadata on \"%ls\" "
                                 "(status=0x%08"PRIx32")",
                                 current_path(ctx), (u32)status);
                return WIMLIB_ERR_SET_ATTRIBUTES;
        }

        return 0;
}

static int
apply_metadata_to_file(const struct wim_dentry *dentry,
                       struct win32_apply_ctx *ctx)
{
        const struct wim_inode *inode = dentry->d_inode;
        DWORD perms;
        HANDLE h;
        NTSTATUS status;
        int ret;

        perms = FILE_WRITE_ATTRIBUTES | WRITE_DAC |
                WRITE_OWNER | ACCESS_SYSTEM_SECURITY;

        build_extraction_path(dentry, ctx);

        /* Open a handle with as many relevant permissions as possible.  */
        while (!NT_SUCCESS(status = do_create_file(&h, perms, NULL,
                                                   0, FILE_OPEN, 0, ctx)))
        {
                if (status == STATUS_PRIVILEGE_NOT_HELD ||
                    status == STATUS_ACCESS_DENIED)
                {
                        if (perms & ACCESS_SYSTEM_SECURITY) {
                                perms &= ~ACCESS_SYSTEM_SECURITY;
                                continue;
                        }
                        if (perms & WRITE_DAC) {
                                perms &= ~WRITE_DAC;
                                continue;
                        }
                        if (perms & WRITE_OWNER) {
                                perms &= ~WRITE_OWNER;
                                continue;
                        }
                }
                set_errno_from_nt_status(status);
                ERROR_WITH_ERRNO("Can't open \"%ls\" to set metadata "
                                 "(status=0x%08"PRIx32")",
                                 current_path(ctx), (u32)status);
                return WIMLIB_ERR_OPEN;
        }

        ret = do_apply_metadata_to_file(h, inode, ctx);

        (*func_NtClose)(h);

        return ret;
}

static int
apply_metadata(struct list_head *dentry_list, struct win32_apply_ctx *ctx)
{
        const struct wim_dentry *dentry;
        int ret;

        /* We go in reverse so that metadata is set on all a directory's
         * children before the directory itself.  This avoids any potential
         * problems with attributes, timestamps, or security descriptors.  */
        list_for_each_entry_reverse(dentry, dentry_list, d_extraction_list_node)
        {
                ret = apply_metadata_to_file(dentry, ctx);
                if (ret)
                        return ret;
        }
        return 0;
}

/* Issue warnings about problems during the extraction for which warnings were
 * not already issued (due to the high number of potential warnings if we issued
 * them per-file).  */
static void
do_warnings(const struct win32_apply_ctx *ctx)
{
        if (ctx->partial_security_descriptors == 0 &&
            ctx->no_security_descriptors == 0)
                return;

        WARNING("Extraction to \"%ls\" complete, but with one or more warnings:",
                ctx->common.target);
        if (ctx->partial_security_descriptors != 0) {
                WARNING("- Could only partially set the security descriptor\n"
                        "            on %lu files or directories.",
                        ctx->partial_security_descriptors);
        }
        if (ctx->no_security_descriptors != 0) {
                WARNING("- Could not set security descriptor at all\n"
                        "            on %lu files or directories.",
                        ctx->no_security_descriptors);
        }
        WARNING("To fully restore all security descriptors, run the program\n"
                "          with Administrator rights.");
}

/* Extract files from a WIM image to a directory on Windows  */
static int
win32_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
{
        int ret;
        struct win32_apply_ctx *ctx = (struct win32_apply_ctx *)_ctx;

        ret = prepare_target(dentry_list, ctx);
        if (ret)
                goto out;

        if (ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT) {
                ret = start_wimboot_extraction(ctx);
                if (ret)
                        goto out;
        }

        ret = create_directories(dentry_list, ctx);
        if (ret)
                goto out;

        ret = create_nondirectories(dentry_list, ctx);
        if (ret)
                goto out;

        struct read_stream_list_callbacks cbs = {
                .begin_stream      = begin_extract_stream,
                .begin_stream_ctx  = ctx,
                .consume_chunk     = extract_chunk,
                .consume_chunk_ctx = ctx,
                .end_stream        = end_extract_stream,
                .end_stream_ctx    = ctx,
        };
        ret = extract_stream_list(&ctx->common, &cbs);
        if (ret)
                goto out;

        ret = apply_metadata(dentry_list, ctx);
        if (ret)
                goto out;

        do_warnings(ctx);
out:
        if (ctx->h_target)
                (*func_NtClose)(ctx->h_target);
        if (ctx->target_ntpath.Buffer)
                HeapFree(GetProcessHeap(), 0, ctx->target_ntpath.Buffer);
        FREE(ctx->pathbuf.Buffer);
        FREE(ctx->print_buffer);
        if (ctx->wimboot.prepopulate_pats) {
                FREE(ctx->wimboot.prepopulate_pats->strings);
                FREE(ctx->wimboot.prepopulate_pats);
        }
        FREE(ctx->wimboot.mem_prepopulate_pats);
        FREE(ctx->data_buffer);
        return ret;
}

const struct apply_operations win32_apply_ops = {
        .name                   = "Windows",
        .get_supported_features = win32_get_supported_features,
        .extract                = win32_extract,
        .context_size           = sizeof(struct win32_apply_ctx),
};

#endif /* __WIN32__ */