Capture and apply extended attributes on Windows

[wimlib] / src / win32_apply.c

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

/*
 * Copyright (C) 2013-2018 Eric Biggers
 *
 * This file is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your option) any
 * later version.
 *
 * This file 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 Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this file; 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/assert.h"
#include "wimlib/blob_table.h"
#include "wimlib/dentry.h"
#include "wimlib/encoding.h"
#include "wimlib/error.h"
#include "wimlib/metadata.h"
#include "wimlib/object_id.h"
#include "wimlib/paths.h"
#include "wimlib/pattern.h"
#include "wimlib/reparse.h"
#include "wimlib/scan.h" /* for mangle_pat() and match_pattern_list()  */
#include "wimlib/textfile.h"
#include "wimlib/wimboot.h"
#include "wimlib/wof.h"
#include "wimlib/xattr.h"
#include "wimlib/xml.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 {
                /* This array contains the WIM files registered with WOF on the
                 * target volume for this extraction operation.  All WIMStructs
                 * in this array are distinct and have ->filename != NULL.  */
                struct wimboot_wim {
                        WIMStruct *wim;
                        u64 data_source_id;
                        u8 blob_table_hash[SHA1_HASH_SIZE];
                } *wims;
                size_t num_wims;
                bool wof_running;
                bool have_wrong_version_wims;
                bool have_uncompressed_wims;
                bool have_unsupported_compressed_resources;
                bool have_huge_resources;
        } wimboot;

        /* External backing information  */
        struct string_list *prepopulate_pats;
        void *mem_prepopulate_pats;
        bool tried_to_load_prepopulate_list;

        /* 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 blob 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_FILES];

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

        /* For each currently open stream, whether we're writing to it in
         * "sparse" mode or not.  */
        bool is_sparse_stream[MAX_OPEN_FILES];

        /* Whether is_sparse_stream[] is true for any currently open stream  */
        bool any_sparse_streams;

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

        /* List of dentries, joined by @d_tmp_list, that need to have raw
         * encrypted data extracted as soon as the whole blob 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;

        /* Number of files for which we couldn't set the short name.  */
        unsigned long num_set_short_name_failures;

        /* Number of files for which we couldn't remove the short name.  */
        unsigned long num_remove_short_name_failures;

        /* Number of files on which we couldn't set System Compression.  */
        unsigned long num_system_compression_failures;

        /* The number of files which, for compatibility with the Windows
         * bootloader, were not compressed using the requested system
         * compression format.  This includes matches with the hardcoded pattern
         * list only; it does not include matches with patterns in
         * [PrepopulateList].  */
        unsigned long num_system_compression_exclusions;

        /* Number of files for which we couldn't set the object ID.  */
        unsigned long num_object_id_failures;

        /* Number of files for which we couldn't set extended attributes.  */
        unsigned long num_xattr_failures;

        /* The Windows build number of the image being applied, or 0 if unknown.
         */
        u64 windows_build_number;

        /* Have we tried to enable short name support on the target volume yet?
         */
        bool tried_to_enable_short_names;
};

/* 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)))
        {
                win32_warning(GetLastError(),
                              L"Failed to get volume information for \"%ls\"",
                              target);
                return;
        }

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

                /* 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;
        }
}

/* Is the image being extracted an OS image for Windows 10 or later?  */
static bool
is_image_windows_10_or_later(struct win32_apply_ctx *ctx)
{
        /* Note: if no build number is available, this returns false.  */
        return ctx->windows_build_number >= 10240;
}

static const wchar_t *
current_path(struct win32_apply_ctx *ctx);

static void
build_extraction_path(const struct wim_dentry *dentry,
                      struct win32_apply_ctx *ctx);

static int
report_dentry_apply_error(const struct wim_dentry *dentry,
                          struct win32_apply_ctx *ctx, int ret)
{
        build_extraction_path(dentry, ctx);
        return report_apply_error(&ctx->common, ret, current_path(ctx));
}

static inline int
check_apply_error(const struct wim_dentry *dentry,
                  struct win32_apply_ctx *ctx, int ret)
{
        if (unlikely(ret))
                ret = report_dentry_apply_error(dentry, ctx, ret);
        return ret;
}

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->readonly_files = 1;
        supported_features->hidden_files = 1;
        supported_features->system_files = 1;
        supported_features->archive_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;

        if (vol_flags & FILE_SUPPORTS_SPARSE_FILES)
                supported_features->sparse_files = 1;

        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;

        if (vol_flags & FILE_SUPPORTS_OBJECT_IDS)
                supported_features->object_ids = 1;

        supported_features->timestamps = 1;

        if (vol_flags & FILE_CASE_SENSITIVE_SEARCH) {
                /*
                 * The filesystem supports case-sensitive filenames.  But does
                 * the operating system as well?  This normally requires the
                 * registry setting ObCaseInsensitive=0.  We can test it
                 * indirectly by attempting to open the "\SystemRoot" symbolic
                 * link using a name with the wrong case.  If we get
                 * STATUS_OBJECT_NAME_NOT_FOUND instead of STATUS_ACCESS_DENIED,
                 * then case-sensitive names must be enabled.
                 */
                UNICODE_STRING path;
                OBJECT_ATTRIBUTES attr;
                HANDLE h;
                NTSTATUS status;

                RtlInitUnicodeString(&path, L"\\systemroot");
                InitializeObjectAttributes(&attr, &path, 0, NULL, NULL);

                status = NtOpenSymbolicLinkObject(&h, 0, &attr);
                if (status == STATUS_OBJECT_NAME_NOT_FOUND)
                        supported_features->case_sensitive_filenames = 1;
        }

        if (vol_flags & FILE_SUPPORTS_EXTENDED_ATTRIBUTES)
                supported_features->xattrs = 1;

        return 0;
}

#define COMPACT_FLAGS   (WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS4K |         \
                         WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS8K |         \
                         WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS16K |        \
                         WIMLIB_EXTRACT_FLAG_COMPACT_LZX)



/*
 * If not done already, load the patterns from the [PrepopulateList] section of
 * WimBootCompress.ini in the WIM image being extracted.
 *
 * Note: WimBootCompress.ini applies to both types of "external backing":
 *
 *      - WIM backing ("WIMBoot" - Windows 8.1 and later)
 *      - File backing ("System Compression" - Windows 10 and later)
 */
static int
load_prepopulate_pats(struct win32_apply_ctx *ctx)
{
        const wchar_t *path = L"\\Windows\\System32\\WimBootCompress.ini";
        struct wim_dentry *dentry;
        const struct blob_descriptor *blob;
        int ret;
        void *buf;
        struct string_list *strings;
        void *mem;
        struct text_file_section sec;

        if (ctx->tried_to_load_prepopulate_list)
                return 0;

        ctx->tried_to_load_prepopulate_list = true;

        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)) ||
            !(blob = inode_get_blob_for_unnamed_data_stream(dentry->d_inode,
                                                            ctx->common.wim->blob_table)))
        {
                WARNING("%ls does not exist in the WIM image.\n"
                        "          The default configuration will be used instead; it assumes that all\n"
                        "          files are valid for external backing regardless of path, equivalent\n"
                        "          to an empty [PrepopulateList] section.", path);
                return WIMLIB_ERR_PATH_DOES_NOT_EXIST;
        }

        ret = read_blob_into_alloc_buf(blob, &buf);
        if (ret)
                return ret;

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

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

        ret = do_load_text_file(path, buf, blob->size, &mem, &sec, 1,
                                LOAD_TEXT_FILE_REMOVE_QUOTES |
                                        LOAD_TEXT_FILE_NO_WARNINGS,
                                mangle_pat);
        STATIC_ASSERT(OS_PREFERRED_PATH_SEPARATOR == WIM_PATH_SEPARATOR);
        FREE(buf);
        if (ret) {
                FREE(strings);
                return ret;
        }
        ctx->prepopulate_pats = strings;
        ctx->mem_prepopulate_pats = mem;
        return 0;
}

/* Returns %true if the specified absolute path to a file in the WIM image can
 * be subject to external backing when extracted.  Otherwise returns %false.  */
static bool
can_externally_back_path(const wchar_t *path, const struct win32_apply_ctx *ctx)
{
        /* Does the path match a pattern given in the [PrepopulateList] section
         * of WimBootCompress.ini?  */
        if (ctx->prepopulate_pats && match_pattern_list(path, ctx->prepopulate_pats))
                return false;

        /* Since we attempt to modify the SYSTEM registry after it's extracted
         * (see end_wimboot_extraction()), it can't be extracted as externally
         * backed.  This extends to associated files such as SYSTEM.LOG that
         * also must be writable in order to write to the registry.  Normally,
         * SYSTEM is in [PrepopulateList], and the SYSTEM.* files match patterns
         * in [ExclusionList] and therefore are not captured in the WIM at all.
         * However, a WIM that wasn't specifically captured in "WIMBoot mode"
         * may contain SYSTEM.* files.  So to make things "just work", hard-code
         * the pattern.  */
        if (match_path(path, L"\\Windows\\System32\\config\\SYSTEM*", false))
                return false;

        return true;
}

/* Can the specified WIM resource be used as the source of an external backing
 * for the wof.sys WIM provider?  */
static bool
is_resource_valid_for_external_backing(const struct wim_resource_descriptor *rdesc,
                                       struct win32_apply_ctx *ctx)
{
        /* Must be the original WIM file format.  This check excludes pipable
         * resources and solid resources.  It also excludes other resources
         * contained in such files even if they would be otherwise compatible.
         */
        if (rdesc->wim->hdr.magic != WIM_MAGIC ||
            rdesc->wim->hdr.wim_version != WIM_VERSION_DEFAULT)
        {
                ctx->wimboot.have_wrong_version_wims = true;
                return false;
        }

        /*
         * Whitelist of compression types and chunk sizes supported by
         * Microsoft's WOF driver.
         *
         * Notes:
         *    - Uncompressed WIMs result in BSOD.  However, this only applies to
         *      the WIM file itself, not to uncompressed resources in a WIM file
         *      that is otherwise compressed.
         *    - XPRESS 64K sometimes appears to work, but sometimes it causes
         *      reads to fail with STATUS_UNSUCCESSFUL.
         */
        switch (rdesc->compression_type) {
        case WIMLIB_COMPRESSION_TYPE_NONE:
                if (rdesc->wim->compression_type == WIMLIB_COMPRESSION_TYPE_NONE) {
                        ctx->wimboot.have_uncompressed_wims = true;
                        return false;
                }
                break;
        case WIMLIB_COMPRESSION_TYPE_XPRESS:
                switch (rdesc->chunk_size) {
                case 4096:
                case 8192:
                case 16384:
                case 32768:
                        break;
                default:
                        ctx->wimboot.have_unsupported_compressed_resources = true;
                        return false;
                }
                break;
        case WIMLIB_COMPRESSION_TYPE_LZX:
                switch (rdesc->chunk_size) {
                case 32768:
                        break;
                default:
                        ctx->wimboot.have_unsupported_compressed_resources = true;
                        return false;
                }
                break;
        default:
                ctx->wimboot.have_unsupported_compressed_resources = true;
                return false;
        }

        /* Microsoft's WoF driver errors out if it tries to satisfy a read with
         * ending offset >= 4 GiB from an externally backed file.  */
        if (rdesc->uncompressed_size > 4200000000) {
                ctx->wimboot.have_huge_resources = true;
                return false;
        }

        return true;
}

#define EXTERNAL_BACKING_NOT_ENABLED            -1
#define EXTERNAL_BACKING_NOT_POSSIBLE           -2
#define EXTERNAL_BACKING_EXCLUDED               -3

/*
 * Determines whether the specified file will be externally backed.  Returns a
 * negative status code if no, 0 if yes, or a positive wimlib error code on
 * error.  If the file is excluded from external backing based on its path, then
 * *excluded_dentry_ret is set to the dentry for the path that matched the
 * exclusion rule.
 *
 * Note that this logic applies to both types of "external backing":
 *
 *      - WIM backing ("WIMBoot" - Windows 8.1 and later)
 *      - File backing ("System Compression" - Windows 10 and later)
 *
 * However, in the case of WIM backing we also need to validate that the WIM
 * resource that would be the source of the backing is supported by the wof.sys
 * WIM provider.
 */
static int
will_externally_back_inode(struct wim_inode *inode, struct win32_apply_ctx *ctx,
                           const struct wim_dentry **excluded_dentry_ret,
                           bool wimboot_mode)
{
        struct wim_dentry *dentry;
        struct blob_descriptor *blob;
        int ret;

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

        if (inode->i_can_externally_back)
                return 0;

        /* This may do redundant checks because the cached value
         * i_can_externally_back is 2-state (as opposed to 3-state:
         * unknown/no/yes).  But most files can be externally backed, so this
         * way is fine.  */

        if (inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
                                   FILE_ATTRIBUTE_REPARSE_POINT |
                                   FILE_ATTRIBUTE_ENCRYPTED))
                return EXTERNAL_BACKING_NOT_POSSIBLE;

        blob = inode_get_blob_for_unnamed_data_stream_resolved(inode);

        if (!blob)
                return EXTERNAL_BACKING_NOT_POSSIBLE;

        if (wimboot_mode &&
            (blob->blob_location != BLOB_IN_WIM ||
             !is_resource_valid_for_external_backing(blob->rdesc, ctx)))
                return EXTERNAL_BACKING_NOT_POSSIBLE;

        /*
         * We need to check the patterns in [PrepopulateList] against every name
         * of the inode, in case any of them match.
         */

        inode_for_each_extraction_alias(dentry, inode) {

                ret = calculate_dentry_full_path(dentry);
                if (ret)
                        return ret;

                if (!can_externally_back_path(dentry->d_full_path, ctx)) {
                        if (excluded_dentry_ret)
                                *excluded_dentry_ret = dentry;
                        return EXTERNAL_BACKING_EXCLUDED;
                }
        }

        inode->i_can_externally_back = 1;
        return 0;
}

/*
 * Determines if the unnamed data stream of a file will be created as a WIM
 * external backing (a "WIMBoot pointer file"), as opposed to a standard
 * extraction.
 */
static int
win32_will_back_from_wim(struct wim_dentry *dentry, struct apply_ctx *_ctx)
{
        struct win32_apply_ctx *ctx = (struct win32_apply_ctx *)_ctx;

        if (!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT))
                return EXTERNAL_BACKING_NOT_ENABLED;

        return will_externally_back_inode(dentry->d_inode, ctx, NULL, true);
}

/* Find the WOF registration information for the specified WIM file.  */
static struct wimboot_wim *
find_wimboot_wim(WIMStruct *wim_to_find, struct win32_apply_ctx *ctx)
{
        for (size_t i = 0; i < ctx->wimboot.num_wims; i++)
                if (wim_to_find == ctx->wimboot.wims[i].wim)
                        return &ctx->wimboot.wims[i];

        wimlib_assert(0);
        return NULL;
}

static int
set_backed_from_wim(HANDLE h, struct wim_inode *inode, struct win32_apply_ctx *ctx)
{
        int ret;
        const struct wim_dentry *excluded_dentry;
        const struct blob_descriptor *blob;
        const struct wimboot_wim *wimboot_wim;

        ret = will_externally_back_inode(inode, ctx, &excluded_dentry, true);
        if (ret > 0) /* Error.  */
                return ret;

        if (ret < 0 && ret != EXTERNAL_BACKING_EXCLUDED)
                return 0; /* Not externally backing, other than due to exclusion.  */

        if (unlikely(ret == EXTERNAL_BACKING_EXCLUDED)) {
                /* Not externally backing due to exclusion.  */
                union wimlib_progress_info info;

                build_extraction_path(excluded_dentry, ctx);

                info.wimboot_exclude.path_in_wim = excluded_dentry->d_full_path;
                info.wimboot_exclude.extraction_path = current_path(ctx);

                return call_progress(ctx->common.progfunc,
                                     WIMLIB_PROGRESS_MSG_WIMBOOT_EXCLUDE,
                                     &info, ctx->common.progctx);
        }

        /* Externally backing.  */

        blob = inode_get_blob_for_unnamed_data_stream_resolved(inode);
        wimboot_wim = find_wimboot_wim(blob->rdesc->wim, ctx);

        if (unlikely(!wimboot_set_pointer(h,
                                          blob,
                                          wimboot_wim->data_source_id,
                                          wimboot_wim->blob_table_hash,
                                          ctx->wimboot.wof_running)))
        {
                const DWORD err = GetLastError();

                build_extraction_path(inode_first_extraction_dentry(inode), ctx);
                win32_error(err, L"\"%ls\": Couldn't set WIMBoot pointer data",
                            current_path(ctx));
                return WIMLIB_ERR_WIMBOOT;
        }
        return 0;
}

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

static int
register_wim_with_wof(WIMStruct *wim, struct win32_apply_ctx *ctx)
{
        struct wimboot_wim *p;
        int ret;

        /* Check if already registered  */
        for (size_t i = 0; i < ctx->wimboot.num_wims; i++)
                if (wim == ctx->wimboot.wims[i].wim)
                        return 0;

        /* Not yet registered  */

        p = REALLOC(ctx->wimboot.wims,
                    (ctx->wimboot.num_wims + 1) * sizeof(ctx->wimboot.wims[0]));
        if (!p)
                return WIMLIB_ERR_NOMEM;
        ctx->wimboot.wims = p;

        ctx->wimboot.wims[ctx->wimboot.num_wims].wim = wim;

        ret = hash_blob_table(wim, ctx->wimboot.wims[ctx->wimboot.num_wims].blob_table_hash);
        if (ret)
                return ret;

        ret = wimboot_alloc_data_source_id(wim->filename,
                                           wim->hdr.guid,
                                           ctx->common.wim->current_image,
                                           ctx->common.target,
                                           &ctx->wimboot.wims[ctx->wimboot.num_wims].data_source_id,
                                           &ctx->wimboot.wof_running);
        if (ret)
                return ret;

        ctx->wimboot.num_wims++;
        return 0;
}

/* Prepare for doing a "WIMBoot" extraction by registering each source WIM file
 * with WOF on the target volume.  */
static int
start_wimboot_extraction(struct list_head *dentry_list, struct win32_apply_ctx *ctx)
{
        int ret;
        struct wim_dentry *dentry;

        if (!xml_get_wimboot(ctx->common.wim->xml_info,
                             ctx->common.wim->current_image))
                WARNING("The WIM image is not marked as WIMBoot compatible.  This usually\n"
                        "          means it is not intended to be used to back a Windows operating\n"
                        "          system.  Proceeding anyway.");

        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
                struct blob_descriptor *blob;

                ret = win32_will_back_from_wim(dentry, &ctx->common);
                if (ret > 0) /* Error */
                        return ret;
                if (ret < 0) /* Won't externally back */
                        continue;

                blob = inode_get_blob_for_unnamed_data_stream_resolved(dentry->d_inode);
                ret = register_wim_with_wof(blob->rdesc->wim, ctx);
                if (ret)
                        return ret;
        }

        if (ctx->wimboot.have_wrong_version_wims) {
  WARNING("At least one of the source WIM files uses a version of the WIM\n"
"          file format that not supported by Microsoft's wof.sys driver.\n"
"          Files whose data is contained in one of these WIM files will be\n"
"          extracted as full files rather than externally backed.");
        }

        if (ctx->wimboot.have_uncompressed_wims) {
  WARNING("At least one of the source WIM files is uncompressed.  Files whose\n"
"          data is contained in an uncompressed WIM file will be extracted as\n"
"          full files rather than externally backed, since uncompressed WIM\n"
"          files are not supported by Microsoft's wof.sys driver.");
        }

        if (ctx->wimboot.have_unsupported_compressed_resources) {
  WARNING("At least one of the source WIM files uses a compression format that\n"
"          is not supported by Microsoft's wof.sys driver.  Files whose data is\n"
"          contained in a compressed resource in one of these WIM files will be\n"
"          extracted as full files rather than externally backed.  (The\n"
"          compression formats supported by wof.sys are: XPRESS 4K, XPRESS 8K,\n"
"          XPRESS 16K, XPRESS 32K, and LZX 32K.)");
        }

        if (ctx->wimboot.have_huge_resources) {
  WARNING("Some files exceeded 4.2 GB in size.  Such files will be extracted\n"
"          as full files rather than externally backed, since very large files\n"
"          are not supported by Microsoft's wof.sys driver.");
        }

        return 0;
}

static void
build_win32_extraction_path(const struct wim_dentry *dentry,
                            struct win32_apply_ctx *ctx);

/* Sets WimBoot=1 in the extracted SYSTEM registry hive.
 *
 * WIMGAPI does this, and it's possible that it's important.
 * But I don't know exactly what this value means to Windows.  */
static int
end_wimboot_extraction(struct win32_apply_ctx *ctx)
{
        struct wim_dentry *dentry;
        wchar_t subkeyname[32];
        LONG res;
        LONG res2;
        HKEY key;
        DWORD value;

        dentry = get_dentry(ctx->common.wim, L"\\Windows\\System32\\config\\SYSTEM",
                            WIMLIB_CASE_INSENSITIVE);

        if (!dentry || !will_extract_dentry(dentry))
                goto out;

        if (!will_extract_dentry(wim_get_current_root_dentry(ctx->common.wim)))
                goto out;

        /* Not bothering to use the native routines (e.g. NtLoadKey()) for this.
         * If this doesn't work, you probably also have many other problems.  */

        build_win32_extraction_path(dentry, ctx);

        get_random_alnum_chars(subkeyname, 20);
        subkeyname[20] = L'\0';

        res = RegLoadKey(HKEY_LOCAL_MACHINE, subkeyname, ctx->pathbuf.Buffer);
        if (res)
                goto out_check_res;

        wcscpy(&subkeyname[20], L"\\Setup");

        res = RegCreateKeyEx(HKEY_LOCAL_MACHINE, subkeyname, 0, NULL,
                             REG_OPTION_BACKUP_RESTORE, 0, NULL, &key, NULL);
        if (res)
                goto out_unload_key;

        value = 1;

        res = RegSetValueEx(key, L"WimBoot", 0, REG_DWORD,
                            (const BYTE *)&value, sizeof(DWORD));
        if (res)
                goto out_close_key;

        res = RegFlushKey(key);

out_close_key:
        res2 = RegCloseKey(key);
        if (!res)
                res = res2;
out_unload_key:
        subkeyname[20] = L'\0';
        RegUnLoadKey(HKEY_LOCAL_MACHINE, subkeyname);
out_check_res:
        if (res) {
                /* Warning only.  */
                win32_warning(res, L"Failed to set \\Setup: dword \"WimBoot\"=1 "
                              "value in registry hive \"%ls\"",
                              ctx->pathbuf.Buffer);
        }
out:
        return 0;
}

/* 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 (unsigned i = 0; i < inode->i_num_streams; i++) {
                const struct wim_inode_stream *strm = &inode->i_streams[i];
                if (!stream_is_named_data_stream(strm))
                        continue;
                size_t len = utf16le_len_chars(strm->stream_name);
                if (len > max)
                        max = len;
        }
        if (max)
                max += 1;
        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;
                if (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, and the registry manipulation in WIMBoot mode.  */
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;
}

/* Open handle to the target directory if it is not already open.  If the target
 * directory does not exist, this creates it.  */
static int
open_target_directory(struct win32_apply_ctx *ctx)
{
        NTSTATUS status;

        if (ctx->h_target)
                return 0;

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

        /* Don't use FILE_OPEN_REPARSE_POINT here; we want the extraction to
         * happen at the directory "pointed to" by the reparse point. */
        status = NtCreateFile(&ctx->h_target,
                              FILE_TRAVERSE,
                              &ctx->attr,
                              &ctx->iosb,
                              NULL,
                              0,
                              FILE_SHARE_VALID_FLAGS,
                              FILE_OPEN_IF,
                              FILE_DIRECTORY_FILE | FILE_OPEN_FOR_BACKUP_INTENT,
                              NULL,
                              0);
        if (!NT_SUCCESS(status)) {
                winnt_error(status, L"Can't open or create directory \"%ls\"",
                            ctx->common.target);
                return WIMLIB_ERR_OPENDIR;
        }
        ctx->attr.RootDirectory = ctx->h_target;
        ctx->attr.ObjectName = &ctx->pathbuf;
        return 0;
}

static void
close_target_directory(struct win32_apply_ctx *ctx)
{
        if (ctx->h_target) {
                NtClose(ctx->h_target);
                ctx->h_target = NULL;
                ctx->attr.RootDirectory = NULL;
        }
}

/*
 * 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;
        size_t path_max;

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

        ret = open_target_directory(ctx);
        if (ret)
                return ret;

        path_max = compute_path_max(dentry_list);
        /* Add some extra for building Win32 paths for the file encryption APIs,
         * and ensure we have at least enough to potentially use a 8.3 name for
         * the last component.  */
        path_max += max(2 + (ctx->target_ntpath.Length / sizeof(wchar_t)),
                        8 + 1 + 3);

        ctx->pathbuf.MaximumLength = path_max * sizeof(wchar_t);
        if (ctx->pathbuf.MaximumLength != path_max * sizeof(wchar_t)) {
                /* Paths are too long for a UNICODE_STRING! */
                ERROR("Some paths are too long to extract (> 32768 characters)!");
                return WIMLIB_ERR_UNSUPPORTED;
        }

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

        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 struct wim_dentry *
first_extraction_alias(const struct wim_inode *inode)
{
        struct wim_dentry *dentry;

        inode_for_each_extraction_alias(dentry, inode)
                if (dentry_has_short_name(dentry))
                        return dentry;
        return inode_first_extraction_dentry(inode);
}

/*
 * 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);
        FILE_BASIC_INFORMATION info;
        USHORT compression_state;
        NTSTATUS status;

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

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


        /* Get current attributes  */
        status = 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 = winnt_fsctl(h, FSCTL_SET_COMPRESSION,
                             &compression_state, sizeof(USHORT), NULL, 0, NULL);
        if (NT_SUCCESS(status))
                return 0;

        winnt_error(status, L"Can't %s compression attribute on \"%ls\"",
                    (compressed ? "set" : "clear"), current_path(ctx));
        return WIMLIB_ERR_SET_ATTRIBUTES;
}

static bool
need_sparse_flag(const struct wim_inode *inode,
                 const struct win32_apply_ctx *ctx)
{
        return (inode->i_attributes & FILE_ATTRIBUTE_SPARSE_FILE) &&
                ctx->common.supported_features.sparse_files;
}

static int
set_sparse_flag(HANDLE h, struct win32_apply_ctx *ctx)
{
        NTSTATUS status;

        status = winnt_fsctl(h, FSCTL_SET_SPARSE, NULL, 0, NULL, 0, NULL);
        if (NT_SUCCESS(status))
                return 0;

        winnt_error(status, L"Can't set sparse flag on \"%ls\"",
                    current_path(ctx));
        return WIMLIB_ERR_SET_ATTRIBUTES;
}

/* Try to enable short name support on the target volume.  If successful, return
 * true.  If unsuccessful, issue a warning and return false.  */
static bool
try_to_enable_short_names(const wchar_t *volume)
{
        HANDLE h;
        FILE_FS_PERSISTENT_VOLUME_INFORMATION info;
        BOOL bret;
        DWORD bytesReturned;

        h = CreateFile(volume, GENERIC_WRITE,
                       FILE_SHARE_VALID_FLAGS, NULL, OPEN_EXISTING,
                       FILE_FLAG_BACKUP_SEMANTICS, NULL);
        if (h == INVALID_HANDLE_VALUE)
                goto fail;

        info.VolumeFlags = 0;
        info.FlagMask = PERSISTENT_VOLUME_STATE_SHORT_NAME_CREATION_DISABLED;
        info.Version = 1;
        info.Reserved = 0;

        bret = DeviceIoControl(h, FSCTL_SET_PERSISTENT_VOLUME_STATE,
                               &info, sizeof(info), NULL, 0,
                               &bytesReturned, NULL);

        CloseHandle(h);

        if (!bret)
                goto fail;
        return true;

fail:
        win32_warning(GetLastError(),
                      L"Failed to enable short name support on %ls",
                      volume + 4);
        return false;
}

static NTSTATUS
remove_conflicting_short_name(const struct wim_dentry *dentry, struct win32_apply_ctx *ctx)
{
        wchar_t *name;
        wchar_t *end;
        NTSTATUS status;
        HANDLE h;
        size_t bufsize = offsetof(FILE_NAME_INFORMATION, FileName) +
                         (13 * sizeof(wchar_t));
        u8 buf[bufsize] _aligned_attribute(8);
        bool retried = false;
        FILE_NAME_INFORMATION *info = (FILE_NAME_INFORMATION *)buf;

        memset(buf, 0, bufsize);

        /* Build the path with the short name.  */
        name = &ctx->pathbuf.Buffer[ctx->pathbuf.Length / sizeof(wchar_t)];
        while (name != ctx->pathbuf.Buffer && *(name - 1) != L'\\')
                name--;
        end = mempcpy(name, dentry->d_short_name, dentry->d_short_name_nbytes);
        ctx->pathbuf.Length = ((u8 *)end - (u8 *)ctx->pathbuf.Buffer);

        /* Open the conflicting file (by short name).  */
        status = NtOpenFile(&h, GENERIC_WRITE | DELETE,
                            &ctx->attr, &ctx->iosb,
                            FILE_SHARE_VALID_FLAGS,
                            FILE_OPEN_REPARSE_POINT | FILE_OPEN_FOR_BACKUP_INTENT);
        if (!NT_SUCCESS(status)) {
                winnt_warning(status, L"Can't open \"%ls\"", current_path(ctx));
                goto out;
        }

#if 0
        WARNING("Overriding conflicting short name; path=\"%ls\"",
                current_path(ctx));
#endif

        /* Try to remove the short name on the conflicting file.  */

retry:
        status = NtSetInformationFile(h, &ctx->iosb, info, bufsize,
                                      FileShortNameInformation);

        if (status == STATUS_INVALID_PARAMETER && !retried) {
                /* Microsoft forgot to make it possible to remove short names
                 * until Windows 7.  Oops.  Use a random short name instead.  */
                get_random_alnum_chars(info->FileName, 8);
                wcscpy(&info->FileName[8], L".WLB");
                info->FileNameLength = 12 * sizeof(wchar_t);
                retried = true;
                goto retry;
        }
        NtClose(h);
out:
        build_extraction_path(dentry, ctx);
        return status;
}

/* 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)
{

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

        /*
         * Note: The size of the FILE_NAME_INFORMATION buffer must be such that
         * FileName contains at least 2 wide characters (4 bytes).  Otherwise,
         * NtSetInformationFile() will return STATUS_INFO_LENGTH_MISMATCH.  This
         * is despite the fact that FileNameLength can validly be 0 or 2 bytes,
         * with the former case being removing the existing short name if
         * present, rather than setting one.
         *
         * The null terminator is seemingly optional, but to be safe we include
         * space for it and zero all unused space.
         */

        size_t bufsize = offsetof(FILE_NAME_INFORMATION, FileName) +
                         max(dentry->d_short_name_nbytes, sizeof(wchar_t)) +
                         sizeof(wchar_t);
        u8 buf[bufsize] _aligned_attribute(8);
        FILE_NAME_INFORMATION *info = (FILE_NAME_INFORMATION *)buf;
        NTSTATUS status;
        bool tried_to_remove_existing = false;

        memset(buf, 0, bufsize);

        info->FileNameLength = dentry->d_short_name_nbytes;
        memcpy(info->FileName, dentry->d_short_name, dentry->d_short_name_nbytes);

retry:
        status = NtSetInformationFile(h, &ctx->iosb, info, bufsize,
                                      FileShortNameInformation);
        if (NT_SUCCESS(status))
                return 0;

        if (status == STATUS_SHORT_NAMES_NOT_ENABLED_ON_VOLUME) {
                if (dentry->d_short_name_nbytes == 0)
                        return 0;
                if (!ctx->tried_to_enable_short_names) {
                        wchar_t volume[7];
                        int ret;

                        ctx->tried_to_enable_short_names = true;

                        ret = win32_get_drive_path(ctx->common.target,
                                                   volume);
                        if (ret)
                                return ret;
                        if (try_to_enable_short_names(volume))
                                goto retry;
                }
        }

        /*
         * Short names can conflict in several cases:
         *
         * - a file being extracted has a short name conflicting with an
         *   existing file
         *
         * - a file being extracted has a short name conflicting with another
         *   file being extracted (possible, but shouldn't happen)
         *
         * - a file being extracted has a short name that conflicts with the
         *   automatically generated short name of a file we previously
         *   extracted, but failed to set the short name for.  Sounds unlikely,
         *   but this actually does happen fairly often on versions of Windows
         *   prior to Windows 7 because they do not support removing short names
         *   from files.
         */
        if (unlikely(status == STATUS_OBJECT_NAME_COLLISION) &&
            dentry->d_short_name_nbytes && !tried_to_remove_existing)
        {
                tried_to_remove_existing = true;
                status = remove_conflicting_short_name(dentry, ctx);
                if (NT_SUCCESS(status))
                        goto retry;
        }

        /* 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)) {
                if (dentry->d_short_name_nbytes)
                        ctx->num_set_short_name_failures++;
                else
                        ctx->num_remove_short_name_failures++;
                return 0;
        }

        winnt_error(status, L"Can't set short name on \"%ls\"", current_path(ctx));
        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 SYNCHRONIZE access, 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 NtCreateFile(FileHandle,
                            DesiredAccess | SYNCHRONIZE,
                            &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);
}

static int
delete_file_or_stream(struct win32_apply_ctx *ctx)
{
        NTSTATUS status;
        HANDLE h;
        ULONG perms = DELETE;
        ULONG flags = FILE_NON_DIRECTORY_FILE | FILE_DELETE_ON_CLOSE;

        /* First try opening the file with FILE_DELETE_ON_CLOSE.  In most cases,
         * all we have to do is that plus close the file handle.  */
retry:
        status = do_create_file(&h, perms, NULL, 0, FILE_OPEN, flags, ctx);

        if (unlikely(status == STATUS_CANNOT_DELETE)) {
                /* This error occurs for files with FILE_ATTRIBUTE_READONLY set.
                 * Try an alternate approach: first open the file without
                 * FILE_DELETE_ON_CLOSE, then reset the file attributes, then
                 * set the "delete" disposition on the handle.  */
                if (flags & FILE_DELETE_ON_CLOSE) {
                        flags &= ~FILE_DELETE_ON_CLOSE;
                        perms |= FILE_WRITE_ATTRIBUTES;
                        goto retry;
                }
        }

        if (unlikely(!NT_SUCCESS(status))) {
                winnt_error(status, L"Can't open \"%ls\" for deletion "
                            "(perms=%x, flags=%x)",
                            current_path(ctx), perms, flags);
                return WIMLIB_ERR_OPEN;
        }

        if (unlikely(!(flags & FILE_DELETE_ON_CLOSE))) {

                FILE_BASIC_INFORMATION basic_info =
                        { .FileAttributes = FILE_ATTRIBUTE_NORMAL };
                status = NtSetInformationFile(h, &ctx->iosb, &basic_info,
                                              sizeof(basic_info),
                                              FileBasicInformation);

                if (!NT_SUCCESS(status)) {
                        winnt_error(status, L"Can't reset attributes of \"%ls\" "
                                    "to prepare for deletion", current_path(ctx));
                        NtClose(h);
                        return WIMLIB_ERR_SET_ATTRIBUTES;
                }

                FILE_DISPOSITION_INFORMATION disp_info =
                        { .DoDeleteFile = TRUE };
                status = NtSetInformationFile(h, &ctx->iosb, &disp_info,
                                              sizeof(disp_info),
                                              FileDispositionInformation);
                if (!NT_SUCCESS(status)) {
                        winnt_error(status, L"Can't set delete-on-close "
                                    "disposition on \"%ls\"", current_path(ctx));
                        NtClose(h);
                        return WIMLIB_ERR_SET_ATTRIBUTES;
                }
        }

        status = NtClose(h);
        if (unlikely(!NT_SUCCESS(status))) {
                winnt_error(status, L"Error closing \"%ls\" after setting "
                            "delete-on-close disposition", current_path(ctx));
                return WIMLIB_ERR_OPEN;
        }

        return 0;
}

/*
 * Create a nondirectory file or named data stream at the current path,
 * superseding any that already exists at that path.  If successful, return an
 * open handle to the file or named data stream with the requested permissions.
 */
static int
supersede_file_or_stream(struct win32_apply_ctx *ctx, DWORD perms,
                         HANDLE *h_ret)
{
        NTSTATUS status;
        bool retried = false;

        /* FILE_ATTRIBUTE_SYSTEM is needed to ensure that
         * FILE_ATTRIBUTE_ENCRYPTED doesn't get set before we want it to be.  */
retry:
        status = do_create_file(h_ret,
                                perms,
                                NULL,
                                FILE_ATTRIBUTE_SYSTEM,
                                FILE_CREATE,
                                FILE_NON_DIRECTORY_FILE,
                                ctx);
        if (likely(NT_SUCCESS(status)))
                return 0;

        /* STATUS_OBJECT_NAME_COLLISION means that the file or stream already
         * exists.  Delete the existing file or stream, then try again.
         *
         * Note: we don't use FILE_OVERWRITE_IF or FILE_SUPERSEDE because of
         * problems with certain file attributes, especially
         * FILE_ATTRIBUTE_ENCRYPTED.  FILE_SUPERSEDE is also broken in the
         * Windows PE ramdisk.  */
        if (status == STATUS_OBJECT_NAME_COLLISION && !retried) {
                int ret = delete_file_or_stream(ctx);
                if (ret)
                        return ret;
                retried = true;
                goto retry;
        }
        winnt_error(status, L"Can't create \"%ls\"", current_path(ctx));
        return WIMLIB_ERR_OPEN;
}

/* Set the reparse point @rpbuf of length @rpbuflen on the extracted file
 * corresponding to the WIM dentry @dentry.  */
static int
do_set_reparse_point(const struct wim_dentry *dentry,
                     const struct reparse_buffer_disk *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 = winnt_fsctl(h, FSCTL_SET_REPARSE_POINT,
                             rpbuf, rpbuflen, NULL, 0, NULL);
        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:
        winnt_error(status, L"Can't set reparse data on \"%ls\"",
                    current_path(ctx));
        return WIMLIB_ERR_SET_REPARSE_DATA;
}

/*
 * Create empty named data streams and potentially a reparse point for the
 * specified file, if any.
 *
 * Since these won't have blob descriptors, they won't show up in the call to
 * extract_blob_list().  Hence the need for the special case.
 */
static int
create_empty_streams(const struct wim_dentry *dentry,
                     struct win32_apply_ctx *ctx)
{
        const struct wim_inode *inode = dentry->d_inode;
        int ret;

        for (unsigned i = 0; i < inode->i_num_streams; i++) {
                const struct wim_inode_stream *strm = &inode->i_streams[i];

                if (stream_blob_resolved(strm) != NULL)
                        continue;

                if (strm->stream_type == STREAM_TYPE_REPARSE_POINT &&
                    ctx->common.supported_features.reparse_points)
                {
                        u8 buf[REPARSE_DATA_OFFSET] _aligned_attribute(8);
                        struct reparse_buffer_disk *rpbuf =
                                (struct reparse_buffer_disk *)buf;
                        complete_reparse_point(rpbuf, inode, 0);
                        ret = do_set_reparse_point(dentry, rpbuf,
                                                   REPARSE_DATA_OFFSET, ctx);
                        if (ret)
                                return ret;
                } else if (stream_is_named_data_stream(strm) &&
                           ctx->common.supported_features.named_data_streams)
                {
                        HANDLE h;

                        build_extraction_path_with_ads(dentry, ctx,
                                                       strm->stream_name,
                                                       utf16le_len_chars(strm->stream_name));
                        /*
                         * Note: do not request any permissions on the handle.
                         * Otherwise, we may encounter a Windows bug where the
                         * parent directory DACL denies read access to the new
                         * named data stream, even when using backup semantics!
                         */
                        ret = supersede_file_or_stream(ctx, 0, &h);

                        build_extraction_path(dentry, ctx);

                        if (ret)
                                return ret;
                        NtClose(h);
                }
        }

        return 0;
}

/*
 * 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)
{
        DWORD perms;
        NTSTATUS status;
        HANDLE h;
        int ret;

        /* DELETE is needed for set_short_name(); GENERIC_READ and GENERIC_WRITE
         * are needed for adjust_compression_attribute().  */
        perms = GENERIC_READ | GENERIC_WRITE;
        if (!dentry_is_root(dentry))
                perms |= DELETE;

        /* FILE_ATTRIBUTE_SYSTEM is needed to ensure that
         * FILE_ATTRIBUTE_ENCRYPTED doesn't get set before we want it to be.  */
        status = create_file(&h, perms, NULL, FILE_ATTRIBUTE_SYSTEM,
                             FILE_OPEN_IF, FILE_DIRECTORY_FILE, dentry, ctx);
        if (unlikely(!NT_SUCCESS(status))) {
                const wchar_t *path = current_path(ctx);
                winnt_error(status, L"Can't create directory \"%ls\"", path);

                /* Check for known issue with WindowsApps directory.  */
                if (status == STATUS_ACCESS_DENIED &&
                    (wcsstr(path, L"\\WindowsApps\\") ||
                     wcsstr(path, L"\\InfusedApps\\"))) {
                        ERROR(
"You seem to be trying to extract files to the WindowsApps directory.\n"
"        Windows 8.1 and later use new file permissions in this directory that\n"
"        cannot be overridden, even by backup/restore programs.  To extract your\n"
"        files anyway, you need to choose a different target directory, delete\n"
"        the WindowsApps directory entirely, reformat the volume, do the\n"
"        extraction from a non-broken operating system such as Windows 7 or\n"
"        Linux, or wait for Microsoft to fix the design flaw in their operating\n"
"        system.  This is *not* a bug in wimlib.  See this thread for more\n"
"        information: https://wimlib.net/forums/viewtopic.php?f=1&t=261");
                }
                return WIMLIB_ERR_MKDIR;
        }

        if (ctx->iosb.Information == FILE_OPENED) {
                /* If we opened an existing directory, try to clear its file
                 * attributes.  As far as I know, this only actually makes a
                 * difference in the case where a FILE_ATTRIBUTE_READONLY
                 * directory has a named data stream which needs to be
                 * extracted.  You cannot create a named data stream of such a
                 * directory, even though this contradicts Microsoft's
                 * documentation for FILE_ATTRIBUTE_READONLY which states it is
                 * not honored for directories!  */
                if (!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ATTRIBUTES)) {
                        FILE_BASIC_INFORMATION basic_info =
                                { .FileAttributes = FILE_ATTRIBUTE_NORMAL };
                        NtSetInformationFile(h, &ctx->iosb, &basic_info,
                                             sizeof(basic_info),
                                             FileBasicInformation);
                }
        }

        if (!dentry_is_root(dentry)) {
                ret = set_short_name(h, dentry, ctx);
                if (ret)
                        goto out;
        }

        ret = adjust_compression_attribute(h, dentry, ctx);
out:
        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.  */

                ret = create_directory(dentry, ctx);

                if (!ret)
                        ret = create_empty_streams(dentry, ctx);

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

                ret = report_file_created(&ctx->common);
                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 an error code.
 */
static int
create_nondirectory_inode(HANDLE *h_ret, const struct wim_dentry *dentry,
                          struct win32_apply_ctx *ctx)
{
        int ret;
        HANDLE h;

        build_extraction_path(dentry, ctx);

        ret = supersede_file_or_stream(ctx,
                                       GENERIC_READ | GENERIC_WRITE | DELETE,
                                       &h);
        if (ret)
                goto out;

        ret = adjust_compression_attribute(h, dentry, ctx);
        if (ret)
                goto out_close;

        if (need_sparse_flag(dentry->d_inode, ctx)) {
                ret = set_sparse_flag(h, ctx);
                if (ret)
                        goto out_close;
        }

        ret = create_empty_streams(dentry, ctx);
        if (ret)
                goto out_close;

        *h_ret = h;
        return 0;

out_close:
        NtClose(h);
out:
        return ret;
}

/* 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 = NtSetInformationFile(h, &ctx->iosb, info, bufsize,
                                              FileLinkInformation);
                if (NT_SUCCESS(status))
                        return 0;
                winnt_error(status, L"Failed to create link \"%ls\"",
                            current_path(ctx));
                return WIMLIB_ERR_LINK;
        } else {
                HANDLE h2;
                int ret;

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

                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 = first_dentry->d_inode;
        const struct wim_dentry *dentry;
        int ret;

        inode_for_each_extraction_alias(dentry, inode) {
                if (dentry != first_dentry) {
                        ret = create_link(h, dentry, ctx);
                        if (ret)
                                return ret;
                }
        }
        return 0;
}

/* Create a nondirectory file, including all links.  */
static int
create_nondirectory(struct wim_inode *inode, struct win32_apply_ctx *ctx)
{
        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);

        /* "WIMBoot" extraction: set external backing by the WIM file if needed.  */
        if (!ret && unlikely(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_WIMBOOT))
                ret = set_backed_from_wim(h, inode, ctx);

        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)
{
        struct wim_dentry *dentry;
        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)) {
                        ret = create_nondirectory(inode, ctx);
                        ret = check_apply_error(dentry, ctx, ret);
                        if (ret)
                                return ret;
                }
                ret = report_file_created(&ctx->common);
                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++)
                NtClose(ctx->open_handles[i]);
}

/* Prepare to read the next blob, which has size @blob_size, into an in-memory
 * buffer.  */
static bool
prepare_data_buffer(struct win32_apply_ctx *ctx, u64 blob_size)
{
        if (blob_size > ctx->data_buffer_size) {
                /* Larger buffer needed.  */
                void *new_buffer;
                if ((size_t)blob_size != blob_size)
                        return false;
                new_buffer = REALLOC(ctx->data_buffer, blob_size);
                if (!new_buffer)
                        return false;
                ctx->data_buffer = new_buffer;
                ctx->data_buffer_size = blob_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 true;
}

static int
begin_extract_blob_instance(const struct blob_descriptor *blob,
                            struct wim_dentry *dentry,
                            const struct wim_inode_stream *strm,
                            struct win32_apply_ctx *ctx)
{
        HANDLE h;
        NTSTATUS status;

        if (unlikely(strm->stream_type == STREAM_TYPE_REPARSE_POINT)) {
                /* We can't write the reparse point 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.  */
                if (!prepare_data_buffer(ctx, blob->size))
                        return WIMLIB_ERR_NOMEM;
                list_add_tail(&dentry->d_tmp_list, &ctx->reparse_dentries);
                return 0;
        }

        if (unlikely(strm->stream_type == STREAM_TYPE_EFSRPC_RAW_DATA)) {
                /* We can't write encrypted files 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 blob 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...  */
                if (!prepare_data_buffer(ctx, blob->size))
                        return WIMLIB_ERR_NOMEM;
                list_add_tail(&dentry->d_tmp_list, &ctx->encrypted_dentries);
                return 0;
        }

        /* It's a data stream (may be unnamed or named).  */
        wimlib_assert(strm->stream_type == STREAM_TYPE_DATA);

        if (ctx->num_open_handles == MAX_OPEN_FILES) {
                /* XXX: Fix this.  But because of the checks in
                 * extract_blob_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;
        }


        if (unlikely(stream_is_named(strm))) {
                build_extraction_path_with_ads(dentry, ctx,
                                               strm->stream_name,
                                               utf16le_len_chars(strm->stream_name));
        } else {
                build_extraction_path(dentry, ctx);
        }


        /* 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)) {
                winnt_error(status, L"Can't open \"%ls\" for writing",
                            current_path(ctx));
                return WIMLIB_ERR_OPEN;
        }

        ctx->is_sparse_stream[ctx->num_open_handles] = false;
        if (need_sparse_flag(dentry->d_inode, ctx)) {
                /* If the stream is unnamed, then the sparse flag was already
                 * set when the file was created.  But if the stream is named,
                 * then we need to set the sparse flag here. */
                if (unlikely(stream_is_named(strm))) {
                        int ret = set_sparse_flag(h, ctx);
                        if (ret) {
                                NtClose(h);
                                return ret;
                        }
                }
                ctx->is_sparse_stream[ctx->num_open_handles] = true;
                ctx->any_sparse_streams = true;
        } else {
                /* Allocate space for the data.  */
                FILE_ALLOCATION_INFORMATION info =
                        { .AllocationSize = { .QuadPart = blob->size }};
                NtSetInformationFile(h, &ctx->iosb, &info, sizeof(info),
                                     FileAllocationInformation);
        }
        ctx->open_handles[ctx->num_open_handles++] = h;
        return 0;
}

/* 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\\",
        };
        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) && !wmemcmp(path, dirs[i], len)) {
                        path += len;
                        while (path != end && *path == L'\\')
                                path++;
                        return 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 but possibly with
 * leading slashes, such as \Windows\System32.
 *
 * The path has an explicit length and is not necessarily null terminated.
 */
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;

        while (path != end && *path != L'\\')
                path++;

        return path;
}

/*
 * Given a reparse point buffer for an inode for which the absolute link target
 * was relativized when it was archived, de-relative the link target to be
 * consistent with the actual extraction location.
 */
static void
try_rpfix(struct reparse_buffer_disk *rpbuf, u16 *rpbuflen_p,
          struct win32_apply_ctx *ctx)
{
        struct link_reparse_point link;
        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;

        /* Do nothing if the reparse data is invalid.  */
        if (parse_link_reparse_point(rpbuf, *rpbuflen_p, &link))
                return;

        /* Do nothing if the reparse point is a relative symbolic link.  */
        if (link_is_relative_symlink(&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 = link.substitute_name_nbytes / sizeof(wchar_t);

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

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

        /* If the target directory is a filesystem root, such as \??\C:\, then
         * it already will have a trailing slash.  Don't include this slash if
         * we are already adding slashes via 'relpath'.  This prevents an extra
         * slash from being generated each time the link is extracted.  And
         * unlike on UNIX, the number of slashes in paths on Windows can be
         * significant; Windows won't understand the link target if it contains
         * too many slashes.  */
        if (target_ntpath_nchars > 0 && relpath_nchars > 0 &&
            ctx->target_ntpath.Buffer[target_ntpath_nchars - 1] == L'\\')
                target_ntpath_nchars--;

        /* Also remove extra slashes from the beginning of 'relpath'.  Normally
         * this isn't needed, but this is here to make the extra slash(es) added
         * by wimlib pre-v1.9.1 get removed automatically.  */
        while (relpath_nchars >= 2 &&
               relpath[0] == L'\\' && relpath[1] == L'\\') {
                relpath++;
                relpath_nchars--;
        }

        fixed_subst_name_nchars = target_ntpath_nchars + relpath_nchars;

        wchar_t fixed_subst_name[fixed_subst_name_nchars];

        wmemcpy(fixed_subst_name, ctx->target_ntpath.Buffer, target_ntpath_nchars);
        wmemcpy(&fixed_subst_name[target_ntpath_nchars], 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);

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

/* Sets the reparse point 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_point(const struct wim_dentry *dentry,
                  const struct reparse_buffer_disk *rpbuf, u16 rpbuflen,
                  struct win32_apply_ctx *ctx)
{
        if ((ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_RPFIX)
            && !(dentry->d_inode->i_rp_flags & WIM_RP_FLAG_NOT_FIXED))
        {
                memcpy(&ctx->rpfixbuf, rpbuf, rpbuflen);
                try_rpfix(&ctx->rpfixbuf, &rpbuflen, ctx);
                rpbuf = &ctx->rpfixbuf;
        }
        return do_set_reparse_point(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 (or directory)
 * corresponding to @dentry.
 *
 * The raw encrypted data is provided in ctx->data_buffer, and its size is
 * ctx->encrypted_size.
 *
 * This function may close the target directory, in which case the caller needs
 * to re-open it if needed.
 */
static int
extract_encrypted_file(const struct wim_dentry *dentry,
                       struct win32_apply_ctx *ctx)
{
        void *rawctx;
        DWORD err;
        ULONG flags;
        bool retried;

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

        flags = CREATE_FOR_IMPORT | OVERWRITE_HIDDEN;
        if (dentry->d_inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY)
                flags |= CREATE_FOR_DIR;

        retried = false;
retry:
        err = OpenEncryptedFileRaw(ctx->pathbuf.Buffer, flags, &rawctx);
        if (err == ERROR_SHARING_VIOLATION && !retried) {
                /* This can be caused by the handle we have open to the target
                 * directory.  Try closing it temporarily.  */
                close_target_directory(ctx);
                retried = true;
                goto retry;
        }

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

        if (err != ERROR_SUCCESS) {
                win32_error(err, L"Can't open \"%ls\" for encrypted import",
                            current_path(ctx));
                return WIMLIB_ERR_OPEN;
        }

        ctx->encrypted_offset = 0;

        err = WriteEncryptedFileRaw(import_encrypted_data, ctx, rawctx);

        CloseEncryptedFileRaw(rawctx);

        if (err != ERROR_SUCCESS) {
                win32_error(err, L"Can't import encrypted file \"%ls\"",
                            current_path(ctx));
                return WIMLIB_ERR_WRITE;
        }

        return 0;
}

/* Called when starting to read a blob for extraction */
static int
win32_begin_extract_blob(struct blob_descriptor *blob, void *_ctx)
{
        struct win32_apply_ctx *ctx = _ctx;
        const struct blob_extraction_target *targets = blob_extraction_targets(blob);
        int ret;

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

        for (u32 i = 0; i < blob->out_refcnt; i++) {
                const struct wim_inode *inode = targets[i].inode;
                const struct wim_inode_stream *strm = targets[i].stream;
                struct wim_dentry *dentry;

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

                if (ctx->common.supported_features.hard_links) {
                        dentry = inode_first_extraction_dentry(inode);
                        ret = begin_extract_blob_instance(blob, dentry, strm, ctx);
                        ret = check_apply_error(dentry, ctx, ret);
                        if (ret)
                                goto fail;
                } else {
                        /* Hard links not supported.  Extract the blob
                         * separately to each alias of the inode.  */
                        inode_for_each_extraction_alias(dentry, inode) {
                                ret = begin_extract_blob_instance(blob, dentry, strm, ctx);
                                ret = check_apply_error(dentry, ctx, ret);
                                if (ret)
                                        goto fail;
                        }
                }
        }

        return 0;

fail:
        close_handles(ctx);
        return ret;
}

static int
pwrite_to_handle(HANDLE h, const void *data, size_t size, u64 offset)
{
        const void * const end = data + size;
        const void *p;
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;

        for (p = data; p != end; p += iosb.Information,
                                 offset += iosb.Information)
        {
                LARGE_INTEGER offs = { .QuadPart = offset };

                status = NtWriteFile(h, NULL, NULL, NULL, &iosb,
                                     (void *)p, min(INT32_MAX, end - p),
                                     &offs, NULL);
                if (!NT_SUCCESS(status)) {
                        winnt_error(status,
                                    L"Error writing data to target volume");
                        return WIMLIB_ERR_WRITE;
                }
        }
        return 0;
}

/* Called when the next chunk of a blob has been read for extraction */
static int
win32_extract_chunk(const struct blob_descriptor *blob, u64 offset,
                    const void *chunk, size_t size, void *_ctx)
{
        struct win32_apply_ctx *ctx = _ctx;
        const void * const end = chunk + size;
        const void *p;
        bool zeroes;
        size_t len;
        unsigned i;
        int ret;

        /*
         * For sparse streams, only write nonzero regions.  This lets the
         * filesystem use holes to represent zero regions.
         */
        for (p = chunk; p != end; p += len, offset += len) {
                zeroes = maybe_detect_sparse_region(p, end - p, &len,
                                                    ctx->any_sparse_streams);
                for (i = 0; i < ctx->num_open_handles; i++) {
                        if (!zeroes || !ctx->is_sparse_stream[i]) {
                                ret = pwrite_to_handle(ctx->open_handles[i],
                                                       p, len, offset);
                                if (ret)
                                        return ret;
                        }
                }
        }

        /* 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;
}

static int
get_system_compression_format(int extract_flags)
{
        if (extract_flags & WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS4K)
                return FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS4K;

        if (extract_flags & WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS8K)
                return FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS8K;

        if (extract_flags & WIMLIB_EXTRACT_FLAG_COMPACT_XPRESS16K)
                return FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS16K;

        return FILE_PROVIDER_COMPRESSION_FORMAT_LZX;
}


static const wchar_t *
get_system_compression_format_string(int format)
{
        switch (format) {
        case FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS4K:
                return L"XPRESS4K";
        case FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS8K:
                return L"XPRESS8K";
        case FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS16K:
                return L"XPRESS16K";
        default:
                return L"LZX";
        }
}

static NTSTATUS
set_system_compression(HANDLE h, int format)
{
        NTSTATUS status;
        struct {
                struct wof_external_info wof_info;
                struct file_provider_external_info file_info;
        } in = {
                .wof_info = {
                        .version = WOF_CURRENT_VERSION,
                        .provider = WOF_PROVIDER_FILE,
                },
                .file_info = {
                        .version = FILE_PROVIDER_CURRENT_VERSION,
                        .compression_format = format,
                },
        };

        /* We intentionally use NtFsControlFile() rather than DeviceIoControl()
         * here because the "compressing this object would not save space"
         * status code does not map to a valid Win32 error code on older
         * versions of Windows (before Windows 10?).  This can be a problem if
         * the WOFADK driver is being used rather than the regular WOF, since
         * WOFADK can be used on older versions of Windows.  */
        status = winnt_fsctl(h, FSCTL_SET_EXTERNAL_BACKING,
                             &in, sizeof(in), NULL, 0, NULL);

        if (status == 0xC000046F) /* "Compressing this object would not save space."  */
                return STATUS_SUCCESS;

        return status;
}

/* Hard-coded list of files which the Windows bootloader may need to access
 * before the WOF driver has been loaded.  */
static const wchar_t * const bootloader_pattern_strings[] = {
        L"*winload.*",
        L"*winresume.*",
        L"\\Windows\\AppPatch\\drvmain.sdb",
        L"\\Windows\\Boot\\DVD\\*",
        L"\\Windows\\Boot\\EFI\\*",
        L"\\Windows\\bootstat.dat",
        L"\\Windows\\Fonts\\vgaoem.fon",
        L"\\Windows\\Fonts\\vgasys.fon",
        L"\\Windows\\INF\\errata.inf",
        L"\\Windows\\System32\\config\\*",
        L"\\Windows\\System32\\ntkrnlpa.exe",
        L"\\Windows\\System32\\ntoskrnl.exe",
        L"\\Windows\\System32\\bootvid.dll",
        L"\\Windows\\System32\\ci.dll",
        L"\\Windows\\System32\\hal*.dll",
        L"\\Windows\\System32\\mcupdate_AuthenticAMD.dll",
        L"\\Windows\\System32\\mcupdate_GenuineIntel.dll",
        L"\\Windows\\System32\\pshed.dll",
        L"\\Windows\\System32\\apisetschema.dll",
        L"\\Windows\\System32\\api-ms-win*.dll",
        L"\\Windows\\System32\\ext-ms-win*.dll",
        L"\\Windows\\System32\\KernelBase.dll",
        L"\\Windows\\System32\\drivers\\*.sys",
        L"\\Windows\\System32\\*.nls",
        L"\\Windows\\System32\\kbd*.dll",
        L"\\Windows\\System32\\kd*.dll",
        L"\\Windows\\System32\\clfs.sys",
        L"\\Windows\\System32\\CodeIntegrity\\driver.stl",
};

static const struct string_list bootloader_patterns = {
        .strings = (wchar_t **)bootloader_pattern_strings,
        .num_strings = ARRAY_LEN(bootloader_pattern_strings),
};

static NTSTATUS
set_system_compression_on_inode(struct wim_inode *inode, int format,
                                struct win32_apply_ctx *ctx)
{
        bool retried = false;
        NTSTATUS status;
        HANDLE h;

        /* If it may be needed for compatibility with the Windows bootloader,
         * force this file to XPRESS4K or uncompressed format.  The bootloader
         * of Windows 10 supports XPRESS4K only; older versions don't support
         * system compression at all.  */
        if (!is_image_windows_10_or_later(ctx) ||
            format != FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS4K)
        {
                /* We need to check the patterns against every name of the
                 * inode, in case any of them match.  */
                struct wim_dentry *dentry;
                inode_for_each_extraction_alias(dentry, inode) {
                        bool incompatible;
                        bool warned;

                        if (calculate_dentry_full_path(dentry)) {
                                ERROR("Unable to compute file path!");
                                return STATUS_NO_MEMORY;
                        }

                        incompatible = match_pattern_list(dentry->d_full_path,
                                                          &bootloader_patterns);
                        FREE(dentry->d_full_path);
                        dentry->d_full_path = NULL;

                        if (!incompatible)
                                continue;

                        warned = (ctx->num_system_compression_exclusions++ > 0);

                        if (is_image_windows_10_or_later(ctx)) {
                                /* Force to XPRESS4K  */
                                if (!warned) {
                                        WARNING("For compatibility with the "
                                                "Windows bootloader, some "
                                                "files are being\n"
                                                "          compacted "
                                                "using the XPRESS4K format "
                                                "instead of the %"TS" format\n"
                                                "          you requested.",
                                                get_system_compression_format_string(format));
                                }
                                format = FILE_PROVIDER_COMPRESSION_FORMAT_XPRESS4K;
                                break;
                        } else {
                                /* Force to uncompressed  */
                                if (!warned) {
                                        WARNING("For compatibility with the "
                                                "Windows bootloader, some "
                                                "files will not\n"
                                                "          be compressed with"
                                                " system compression "
                                                "(\"compacted\").");
                                }
                                return STATUS_SUCCESS;
                        }

                }
        }

        /* Open the extracted file.  */
        status = create_file(&h, GENERIC_READ | GENERIC_WRITE, NULL,
                             0, FILE_OPEN, 0,
                             inode_first_extraction_dentry(inode), ctx);

        if (!NT_SUCCESS(status))
                return status;
retry:
        /* Compress the file.  If the attempt fails with "invalid device
         * request", then attach wof.sys (or wofadk.sys) and retry.  */
        status = set_system_compression(h, format);
        if (unlikely(status == STATUS_INVALID_DEVICE_REQUEST && !retried)) {
                wchar_t drive_path[7];
                if (!win32_get_drive_path(ctx->common.target, drive_path) &&
                    win32_try_to_attach_wof(drive_path + 4)) {
                        retried = true;
                        goto retry;
                }
        }

        NtClose(h);
        return status;
}

/*
 * This function is called when doing a "compact-mode" extraction and we just
 * finished extracting a blob to one or more locations.  For each location that
 * was the unnamed data stream of a file, this function compresses the
 * corresponding file using System Compression, if allowed.
 *
 * Note: we're doing the compression immediately after extracting the data
 * rather than during a separate compression pass.  This way should be faster
 * since the operating system should still have the file's data cached.
 *
 * Note: we're having the operating system do the compression, which is not
 * ideal because wimlib could create the compressed data faster and more
 * efficiently (the compressed data format is identical to a WIM resource).  But
 * we seemingly don't have a choice because WOF prevents applications from
 * creating its reparse points.
 */
static void
handle_system_compression(struct blob_descriptor *blob, struct win32_apply_ctx *ctx)
{
        const struct blob_extraction_target *targets = blob_extraction_targets(blob);

        const int format = get_system_compression_format(ctx->common.extract_flags);

        for (u32 i = 0; i < blob->out_refcnt; i++) {
                struct wim_inode *inode = targets[i].inode;
                struct wim_inode_stream *strm = targets[i].stream;
                NTSTATUS status;

                if (!stream_is_unnamed_data_stream(strm))
                        continue;

                if (will_externally_back_inode(inode, ctx, NULL, false) != 0)
                        continue;

                status = set_system_compression_on_inode(inode, format, ctx);
                if (likely(NT_SUCCESS(status)))
                        continue;

                if (status == STATUS_INVALID_DEVICE_REQUEST) {
                        WARNING(
          "The request to compress the extracted files using System Compression\n"
"          will not be honored because the operating system or target volume\n"
"          does not support it.  System Compression is only supported on\n"
"          Windows 10 and later, and only on NTFS volumes.");
                        ctx->common.extract_flags &= ~COMPACT_FLAGS;
                        return;
                }

                ctx->num_system_compression_failures++;
                if (ctx->num_system_compression_failures < 10) {
                        winnt_warning(status, L"\"%ls\": Failed to compress "
                                      "extracted file using System Compression",
                                      current_path(ctx));
                } else if (ctx->num_system_compression_failures == 10) {
                        WARNING("Suppressing further warnings about "
                                "System Compression failures.");
                }
        }
}

/* Called when a blob has been fully read for extraction */
static int
win32_end_extract_blob(struct blob_descriptor *blob, int status, void *_ctx)
{
        struct win32_apply_ctx *ctx = _ctx;
        int ret;
        const struct wim_dentry *dentry;

        /* Extend sparse streams to their final size. */
        if (ctx->any_sparse_streams && !status) {
                for (unsigned i = 0; i < ctx->num_open_handles; i++) {
                        FILE_END_OF_FILE_INFORMATION info =
                                { .EndOfFile = { .QuadPart = blob->size } };
                        NTSTATUS ntstatus;

                        if (!ctx->is_sparse_stream[i])
                                continue;

                        ntstatus = NtSetInformationFile(ctx->open_handles[i],
                                                        &ctx->iosb,
                                                        &info, sizeof(info),
                                                        FileEndOfFileInformation);
                        if (!NT_SUCCESS(ntstatus)) {
                                winnt_error(ntstatus, L"Error writing data to "
                                            "target volume (while extending)");
                                status = WIMLIB_ERR_WRITE;
                                break;
                        }
                }
        }

        close_handles(ctx);

        if (status)
                return status;

        if (unlikely(ctx->common.extract_flags & COMPACT_FLAGS))
                handle_system_compression(blob, ctx);

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

        if (!list_empty(&ctx->reparse_dentries)) {
                if (blob->size > REPARSE_DATA_MAX_SIZE) {
                        dentry = list_first_entry(&ctx->reparse_dentries,
                                                  struct wim_dentry, d_tmp_list);
                        build_extraction_path(dentry, ctx);
                        ERROR("Reparse data of \"%ls\" has size "
                              "%"PRIu64" bytes (exceeds %u bytes)",
                              current_path(ctx), blob->size,
                              REPARSE_DATA_MAX_SIZE);
                        ret = WIMLIB_ERR_INVALID_REPARSE_DATA;
                        return check_apply_error(dentry, ctx, ret);
                }
                /* Reparse data  */
                memcpy(ctx->rpbuf.rpdata, ctx->data_buffer, blob->size);

                list_for_each_entry(dentry, &ctx->reparse_dentries, d_tmp_list) {

                        /* Reparse point header  */
                        complete_reparse_point(&ctx->rpbuf, dentry->d_inode,
                                               blob->size);

                        ret = set_reparse_point(dentry, &ctx->rpbuf,
                                                REPARSE_DATA_OFFSET + blob->size,
                                                ctx);
                        ret = check_apply_error(dentry, ctx, ret);
                        if (ret)
                                return ret;
                }
        }

        if (!list_empty(&ctx->encrypted_dentries)) {
                ctx->encrypted_size = blob->size;
                list_for_each_entry(dentry, &ctx->encrypted_dentries, d_tmp_list) {
                        ret = extract_encrypted_file(dentry, ctx);
                        ret = check_apply_error(dentry, ctx, ret);
                        if (ret)
                                return ret;
                        /* Re-open the target directory if needed.  */
                        ret = open_target_directory(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)

static void
set_object_id(HANDLE h, const struct wim_inode *inode,
              struct win32_apply_ctx *ctx)
{
        const void *object_id;
        u32 len;
        NTSTATUS status;

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

        object_id = inode_get_object_id(inode, &len);
        if (likely(object_id == NULL))  /* No object ID?  */
                return;

        status = winnt_fsctl(h, FSCTL_SET_OBJECT_ID,
                             object_id, len, NULL, 0, NULL);
        if (NT_SUCCESS(status))
                return;

        /* Object IDs must be unique within the filesystem.  A duplicate might
         * occur if an image containing object IDs is applied twice to the same
         * filesystem.  Arguably, the user should be warned in this case; but
         * the reality seems to be that nothing important cares about object IDs
         * except the Distributed Link Tracking Service... so for now these
         * failures are just ignored.  */
        if (status == STATUS_DUPLICATE_NAME ||
            status == STATUS_OBJECT_NAME_COLLISION)
                return;

        ctx->num_object_id_failures++;
        if (ctx->num_object_id_failures < 10) {
                winnt_warning(status, L"Can't set object ID on \"%ls\"",
                              current_path(ctx));
        } else if (ctx->num_object_id_failures == 10) {
                WARNING("Suppressing further warnings about failure to set "
                        "object IDs.");
        }
}

static int
set_xattrs(HANDLE h, const struct wim_inode *inode, struct win32_apply_ctx *ctx)
{
        const void *entries, *entries_end;
        u32 len;
        const struct wim_xattr_entry *entry;
        size_t bufsize = 0;
        u8 _buf[1024] _aligned_attribute(4);
        u8 *buf = _buf;
        FILE_FULL_EA_INFORMATION *ea, *ea_prev;
        NTSTATUS status;
        int ret;

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

        entries = inode_get_xattrs(inode, &len);
        if (likely(entries == NULL || len == 0))  /* No extended attributes? */
                return 0;
        entries_end = entries + len;

        entry = entries;
        for (entry = entries; (void *)entry < entries_end;
             entry = xattr_entry_next(entry)) {
                if (!valid_xattr_entry(entry, entries_end - (void *)entry)) {
                        ERROR("\"%"TS"\": extended attribute is corrupt or unsupported",
                              inode_any_full_path(inode));
                        return WIMLIB_ERR_INVALID_XATTR;
                }

                bufsize += ALIGN(offsetof(FILE_FULL_EA_INFORMATION, EaName) +
                                 entry->name_len + 1 +
                                 le16_to_cpu(entry->value_len), 4);
        }

        if (unlikely(bufsize != (u32)bufsize)) {
                ERROR("\"%"TS"\": too many extended attributes to extract!",
                      inode_any_full_path(inode));
                return WIMLIB_ERR_INVALID_XATTR;
        }

        if (unlikely(bufsize > sizeof(_buf))) {
                buf = MALLOC(bufsize);
                if (!buf)
                        return WIMLIB_ERR_NOMEM;
        }

        ea_prev = NULL;
        ea = (FILE_FULL_EA_INFORMATION *)buf;
        for (entry = entries; (void *)entry < entries_end;
             entry = xattr_entry_next(entry)) {
                u8 *p;

                if (ea_prev)
                        ea_prev->NextEntryOffset = (u8 *)ea - (u8 *)ea_prev;
                ea->Flags = entry->flags;
                ea->EaNameLength = entry->name_len;
                ea->EaValueLength = le16_to_cpu(entry->value_len);
                p = mempcpy(ea->EaName, entry->name,
                            ea->EaNameLength + 1 + ea->EaValueLength);
                while ((uintptr_t)p & 3)
                        *p++ = 0;
                ea_prev = ea;
                ea = (FILE_FULL_EA_INFORMATION *)p;
        }
        ea_prev->NextEntryOffset = 0;
        wimlib_assert((u8 *)ea - buf == bufsize);

        status = NtSetEaFile(h, &ctx->iosb, buf, bufsize);
        if (unlikely(!NT_SUCCESS(status))) {
                if (status == STATUS_EAS_NOT_SUPPORTED) {
                        /* This happens with Samba. */
                        WARNING("Filesystem advertised extended attribute (EA) support, but it doesn't\n"
                                "          work.  EAs will not be extracted.");
                        ctx->common.supported_features.xattrs = 0;
                } else if (status == STATUS_INVALID_EA_NAME) {
                        ctx->num_xattr_failures++;
                        if (ctx->num_xattr_failures < 5) {
                                winnt_warning(status,
                                              L"Can't set extended attributes on \"%ls\"",
                                              current_path(ctx));
                        } else if (ctx->num_xattr_failures == 5) {
                                WARNING("Suppressing further warnings about "
                                        "failure to set extended attributes.");
                        }
                } else {
                        winnt_error(status, L"Can't set extended attributes on \"%ls\"",
                                    current_path(ctx));
                        ret = WIMLIB_ERR_SET_XATTR;
                        goto out;
                }
        }
        ret = 0;
out:
        if (buf != _buf)
                FREE(buf);
        return ret;
}

/* 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;
        SECURITY_DESCRIPTOR_RELATIVE *desc;

        /*
         * Ideally, we would just pass in the security descriptor buffer as-is.
         * But it turns out that Windows can mess up the security descriptor
         * even when using the low-level NtSetSecurityObject() function:
         *
         * - Windows will clear SE_DACL_AUTO_INHERITED if it is set in the
         *   passed buffer.  To actually get Windows to set
         *   SE_DACL_AUTO_INHERITED, the application must set the non-persistent
         *   flag SE_DACL_AUTO_INHERIT_REQ.  As usual, Microsoft didn't bother
         *   to properly document either of these flags.  It's unclear how
         *   important SE_DACL_AUTO_INHERITED actually is, but to be safe we use
         *   the SE_DACL_AUTO_INHERIT_REQ workaround to set it if needed.
         *
         * - The above also applies to the equivalent SACL flags,
         *   SE_SACL_AUTO_INHERITED and SE_SACL_AUTO_INHERIT_REQ.
         *
         * - If the application says that it's setting
         *   DACL_SECURITY_INFORMATION, then Windows sets SE_DACL_PRESENT in the
         *   resulting security descriptor, even if the security descriptor the
         *   application provided did not have a DACL.  This seems to be
         *   unavoidable, since omitting DACL_SECURITY_INFORMATION would cause a
         *   default DACL to remain.  Fortunately, this behavior seems harmless,
         *   since the resulting DACL will still be "null" --- but it will be
         *   "the other representation of null".
         *
         * - The above also applies to SACL_SECURITY_INFORMATION and
         *   SE_SACL_PRESENT.  Again, it's seemingly unavoidable but "harmless"
         *   that Windows changes the representation of a "null SACL".
         */
        if (likely(desc_size <= STACK_MAX)) {
                desc = alloca(desc_size);
        } else {
                desc = MALLOC(desc_size);
                if (!desc)
                        return STATUS_NO_MEMORY;
        }

        memcpy(desc, _desc, desc_size);

        if (likely(desc_size >= 4)) {

                if (desc->Control & SE_DACL_AUTO_INHERITED)
                        desc->Control |= SE_DACL_AUTO_INHERIT_REQ;

                if (desc->Control & SE_SACL_AUTO_INHERITED)
                        desc->Control |= SE_SACL_AUTO_INHERIT_REQ;
        }

        /*
         * More API insanity.  We want to set the entire security descriptor
         * as-is.  But all available APIs require specifying the specific parts
         * of the security descriptor being set.  Especially annoying is that
         * mandatory integrity labels are part of the SACL, but they aren't set
         * with SACL_SECURITY_INFORMATION.  Instead, applications must also
         * specify LABEL_SECURITY_INFORMATION (Windows Vista, Windows 7) or
         * BACKUP_SECURITY_INFORMATION (Windows 8).  But at least older versions
         * of Windows don't error out if you provide these newer flags...
         *
         * Also, if the process isn't running as Administrator, then it probably
         * doesn't have SE_RESTORE_PRIVILEGE.  In this case, it will always get
         * the STATUS_PRIVILEGE_NOT_HELD error by trying to set the SACL, even
         * if the security descriptor it provided did not have a SACL.  By
         * default, in this case we try to recover and set as much of the
         * security descriptor as possible --- potentially excluding the DACL, and
         * even the owner, as well as the SACL.
         */

        info = OWNER_SECURITY_INFORMATION | GROUP_SECURITY_INFORMATION |
               DACL_SECURITY_INFORMATION | SACL_SECURITY_INFORMATION |
               LABEL_SECURITY_INFORMATION | BACKUP_SECURITY_INFORMATION;


        /*
         * It's also worth noting that SetFileSecurity() is unusable because it
         * doesn't request "backup semantics" when it opens the file internally.
         * NtSetSecurityObject() seems to be the best function to use in backup
         * applications.  (SetSecurityInfo() should also work, but it's harder
         * to use and must call NtSetSecurityObject() internally anyway.
         * BackupWrite() is theoretically usable as well, but it's inflexible
         * and poorly documented.)
         */

retry:
        status = NtSetSecurityObject(h, info, desc);
        if (NT_SUCCESS(status))
                goto out_maybe_free_desc;

        /* 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 |
                                  LABEL_SECURITY_INFORMATION |
                                  BACKUP_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++;

out_maybe_free_desc:
        if (unlikely(desc_size > STACK_MAX))
                FREE(desc);
        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;
        int ret;

        /* Set the file's object ID if present and object IDs are supported by
         * the filesystem.  */
        set_object_id(h, inode, ctx);

        /* Set the file's extended attributes (EAs) if present and EAs are
         * supported by the filesystem.  */
        ret = set_xattrs(h, inode, ctx);
        if (ret)
                return ret;

        /* Set the file's security descriptor if present and we're not in
         * NO_ACLS mode  */
        if (inode_has_security_descriptor(inode) &&
            !(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))
                {
                        winnt_error(status,
                                    L"Can't set security descriptor on \"%ls\"",
                                    current_path(ctx));
                        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 = FILE_ATTRIBUTE_NORMAL;
        } else {
                info.FileAttributes = inode->i_attributes & ~SPECIAL_ATTRIBUTES;
                if (info.FileAttributes == 0)
                        info.FileAttributes = FILE_ATTRIBUTE_NORMAL;
        }

        status = 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))))
        {
                winnt_error(status, L"Can't set basic metadata on \"%ls\"",
                            current_path(ctx));
                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 | FILE_WRITE_EA | 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;
                        }
                }
                winnt_error(status, L"Can't open \"%ls\" to set metadata",
                            current_path(ctx));
                return WIMLIB_ERR_OPEN;
        }

        ret = do_apply_metadata_to_file(h, inode, ctx);

        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);
                ret = check_apply_error(dentry, ctx, ret);
                if (ret)
                        return ret;
                ret = report_file_metadata_applied(&ctx->common);
                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
            && ctx->num_set_short_name_failures == 0
        #if 0
            && ctx->num_remove_short_name_failures == 0
        #endif
            )
                return;

        WARNING("Extraction to \"%ls\" complete, but with one or more warnings:",
                ctx->common.target);
        if (ctx->num_set_short_name_failures) {
                WARNING("- Could not set short names on %lu files or directories",
                        ctx->num_set_short_name_failures);
        }
#if 0
        if (ctx->num_remove_short_name_failures) {
                WARNING("- Could not remove short names on %lu files or directories"
                        "          (This is expected on Vista and earlier)",
                        ctx->num_remove_short_name_failures);
        }
#endif
        if (ctx->partial_security_descriptors) {
                WARNING("- Could only partially set the security descriptor\n"
                        "            on %lu files or directories.",
                        ctx->partial_security_descriptors);
        }
        if (ctx->no_security_descriptors) {
                WARNING("- Could not set security descriptor at all\n"
                        "            on %lu files or directories.",
                        ctx->no_security_descriptors);
        }
        if (ctx->partial_security_descriptors || ctx->no_security_descriptors) {
                WARNING("To fully restore all security descriptors, run the program\n"
                        "          with Administrator rights.");
        }
}

static u64
count_dentries(const struct list_head *dentry_list)
{
        const struct list_head *cur;
        u64 count = 0;

        list_for_each(cur, dentry_list)
                count++;

        return count;
}

/* 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;
        u64 dentry_count;

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

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

        ctx->windows_build_number = xml_get_windows_build_number(ctx->common.wim->xml_info,
                                                                 ctx->common.wim->current_image);

        dentry_count = count_dentries(dentry_list);

        ret = start_file_structure_phase(&ctx->common, dentry_count);
        if (ret)
                goto out;

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

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

        ret = end_file_structure_phase(&ctx->common);
        if (ret)
                goto out;

        struct read_blob_callbacks cbs = {
                .begin_blob     = win32_begin_extract_blob,
                .continue_blob  = win32_extract_chunk,
                .end_blob       = win32_end_extract_blob,
                .ctx            = ctx,
        };
        ret = extract_blob_list(&ctx->common, &cbs);
        if (ret)
                goto out;

        ret = start_file_metadata_phase(&ctx->common, dentry_count);
        if (ret)
                goto out;

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

        ret = end_file_metadata_phase(&ctx->common);
        if (ret)
                goto out;

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

        do_warnings(ctx);
out:
        close_target_directory(ctx);
        if (ctx->target_ntpath.Buffer)
                HeapFree(GetProcessHeap(), 0, ctx->target_ntpath.Buffer);
        FREE(ctx->pathbuf.Buffer);
        FREE(ctx->print_buffer);
        FREE(ctx->wimboot.wims);
        if (ctx->prepopulate_pats) {
                FREE(ctx->prepopulate_pats->strings);
                FREE(ctx->prepopulate_pats);
        }
        FREE(ctx->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,
        .will_back_from_wim     = win32_will_back_from_wim,
        .context_size           = sizeof(struct win32_apply_ctx),
};

#endif /* __WIN32__ */