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[wimlib] / src / wimboot.c
index beb4eab..1650de9 100644 (file)
 /*
  * Copyright (C) 2014 Eric Biggers
  *
- * This file is part of wimlib, a library for working with WIM files.
+ * 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.
  *
- * wimlib is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 3 of the License, or (at your option)
- * any later version.
- *
- * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * 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 General Public License
- * along with wimlib; if not, see http://www.gnu.org/licenses/.
+ * 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/.
  */
 
-#ifndef __WIN32__
-#  error "This file contains Windows code!"
-#endif
+#ifdef __WIN32__
 
 #ifdef HAVE_CONFIG_H
 #  include "config.h"
 #endif
 
 #include "wimlib/win32_common.h"
-#include "wimlib/win32.h"
+
 #include "wimlib/assert.h"
+#include "wimlib/blob_table.h"
+#include "wimlib/inode.h"
 #include "wimlib/error.h"
 #include "wimlib/util.h"
 #include "wimlib/wimboot.h"
+#include "wimlib/win32.h"
 #include "wimlib/wof.h"
 
+static HANDLE
+open_file(const wchar_t *device_name, DWORD desiredAccess)
+{
+       return CreateFile(device_name, desiredAccess,
+                         FILE_SHARE_VALID_FLAGS, NULL, OPEN_EXISTING,
+                         FILE_FLAG_BACKUP_SEMANTICS, NULL);
+}
+
+static BOOL
+query_device(HANDLE h, DWORD code, void *out, DWORD out_size)
+{
+       DWORD bytes_returned;
+       return DeviceIoControl(h, code, NULL, 0, out, out_size,
+                              &bytes_returned, NULL);
+}
+
+/*
+ * Gets partition and drive information for the specified path.
+ *
+ * @path
+ *     Absolute path which must begin with a drive letter.  For example, if the
+ *     path is D:\install.wim, this function will query information about the
+ *     D: volume.
+ * @part_info_ret
+ *     Partition info is returned here.
+ * @drive_info_ret
+ *     Drive info is returned here.  The contained partition info will not be
+ *     valid.
+ *
+ * Returns 0 on success, or a positive error code on failure.
+ */
 static int
-win32_get_drive_path(const wchar_t *file_path, wchar_t drive_path[7])
+query_partition_and_disk_info(const wchar_t *path,
+                             PARTITION_INFORMATION_EX *part_info,
+                             DRIVE_LAYOUT_INFORMATION_EX *drive_info_ret)
 {
-       tchar *file_abspath;
+       wchar_t vol_name[] = L"\\\\.\\X:";
+       wchar_t disk_name[] = L"\\\\?\\PhysicalDriveXXXXXXXXXX";
+       HANDLE h = INVALID_HANDLE_VALUE;
+       VOLUME_DISK_EXTENTS *extents = NULL;
+       size_t extents_size;
+       DRIVE_LAYOUT_INFORMATION_EX *drive_info = NULL;
+       size_t drive_info_size;
+       int ret;
 
-       file_abspath = realpath(file_path, NULL);
-       if (!file_abspath)
-               return WIMLIB_ERR_NOMEM;
+       wimlib_assert(path[0] != L'\0' && path[1] == L':');
+
+       *(wcschr(vol_name, L'X')) = path[0];
+
+       h = open_file(vol_name, GENERIC_READ);
+       if (h == INVALID_HANDLE_VALUE) {
+               win32_error(GetLastError(), L"\"%ls\": Can't open volume device",
+                           vol_name);
+               ret = WIMLIB_ERR_OPEN;
+               goto out;
+       }
+
+       if (!query_device(h, IOCTL_DISK_GET_PARTITION_INFO_EX,
+                         part_info, sizeof(PARTITION_INFORMATION_EX)))
+       {
+               win32_error(GetLastError(),
+                           L"\"%ls\": Can't get partition info", vol_name);
+               ret = WIMLIB_ERR_READ;
+               goto out;
+       }
+
+       extents_size = sizeof(VOLUME_DISK_EXTENTS);
+       for (;;) {
+               extents_size += 4 * sizeof(DISK_EXTENT);
+               extents = MALLOC(extents_size);
+               if (!extents) {
+                       ret = WIMLIB_ERR_NOMEM;
+                       goto out;
+               }
 
-       if (file_abspath[0] == L'\0' || file_abspath[1] != L':') {
-               ERROR("\"%ls\": Path format not recognized", file_abspath);
-               FREE(file_abspath);
+               if (query_device(h, IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,
+                                extents, extents_size))
+                       break;
+               if (GetLastError() != ERROR_MORE_DATA) {
+                       win32_error(GetLastError(),
+                                   L"\"%ls\": Can't get volume extent info",
+                                   vol_name);
+                       ret = WIMLIB_ERR_READ;
+                       goto out;
+               }
+               FREE(extents);
+       }
+
+       CloseHandle(h);
+       h = INVALID_HANDLE_VALUE;
+
+       if (extents->NumberOfDiskExtents != 1) {
+               ERROR("\"%ls\": This volume has %"PRIu32" disk extents, "
+                     "but this code is untested for more than 1",
+                     vol_name, (u32)extents->NumberOfDiskExtents);
+               ret = WIMLIB_ERR_UNSUPPORTED;
+               goto out;
+       }
+
+       wsprintf(wcschr(disk_name, L'X'), L"%"PRIu32,
+                extents->Extents[0].DiskNumber);
+
+       h = open_file(disk_name, GENERIC_READ);
+       if (h == INVALID_HANDLE_VALUE) {
+               win32_error(GetLastError(),
+                           L"\"%ls\": Can't open disk device", disk_name);
+               ret = WIMLIB_ERR_OPEN;
+               goto out;
+       }
+
+       drive_info_size = sizeof(DRIVE_LAYOUT_INFORMATION_EX);
+       for (;;) {
+               drive_info_size += 4 * sizeof(PARTITION_INFORMATION_EX);
+               drive_info = MALLOC(drive_info_size);
+               if (!drive_info) {
+                       ret = WIMLIB_ERR_NOMEM;
+                       goto out;
+               }
+
+               if (query_device(h, IOCTL_DISK_GET_DRIVE_LAYOUT_EX,
+                                drive_info, drive_info_size))
+                       break;
+               if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+                       win32_error(GetLastError(),
+                                   L"\"%ls\": Can't get disk info", disk_name);
+                       ret = WIMLIB_ERR_READ;
+                       goto out;
+               }
+               FREE(drive_info);
+       }
+
+       *drive_info_ret = *drive_info;  /* doesn't include partitions */
+       CloseHandle(h);
+       h = INVALID_HANDLE_VALUE;
+
+       if (drive_info->PartitionStyle != part_info->PartitionStyle) {
+               ERROR("\"%ls\", \"%ls\": Inconsistent partition table type!",
+                     vol_name, disk_name);
+               ret = WIMLIB_ERR_UNSUPPORTED;
+               goto out;
+       }
+
+       if (part_info->PartitionStyle == PARTITION_STYLE_GPT) {
+               STATIC_ASSERT(sizeof(part_info->Gpt.PartitionId) ==
+                             sizeof(drive_info->Gpt.DiskId));
+               if (!memcmp(&part_info->Gpt.PartitionId,
+                           &drive_info->Gpt.DiskId,
+                           sizeof(drive_info->Gpt.DiskId)))
+               {
+                       ERROR("\"%ls\", \"%ls\": Partition GUID is the "
+                             "same as the disk GUID???", vol_name, disk_name);
+                       ret = WIMLIB_ERR_UNSUPPORTED;
+                       goto out;
+               }
+       }
+
+       if (part_info->PartitionStyle != PARTITION_STYLE_MBR &&
+           part_info->PartitionStyle != PARTITION_STYLE_GPT)
+       {
+               ERROR("\"%ls\": Unknown partition style 0x%08"PRIx32,
+                     vol_name, (u32)part_info->PartitionStyle);
+               ret = WIMLIB_ERR_UNSUPPORTED;
+               goto out;
+       }
+
+       ret = 0;
+out:
+       FREE(extents);
+       FREE(drive_info);
+       if (h != INVALID_HANDLE_VALUE)
+               CloseHandle(h);
+       return ret;
+}
+
+/*
+ * Allocate a new WIM data source ID.
+ *
+ * @old_hdr
+ *     Previous WimOverlay.dat contents, or NULL if file did not exist.
+ *
+ * Returns the new data source ID.
+ */
+static u64
+alloc_new_data_source_id(const struct WimOverlay_dat_header *old_hdr)
+{
+       if (!old_hdr)
+               return 0;
+
+       for (u64 id = 0; ; id++) {
+               for (u32 i = 0; i < old_hdr->num_entries_1; i++)
+                       if (id == old_hdr->entry_1s[i].data_source_id)
+                               goto next;
+               return id;
+       next:
+               ;
+       }
+}
+
+/*
+ * Calculate the size of WimOverlay.dat with one entry added.
+ *
+ * @old_hdr
+ *     Previous WimOverlay.dat contents, or NULL if file did not exist.
+ * @new_entry_2_size
+ *     Size of entry_2 being added.
+ * @size_ret
+ *     Size will be returned here.
+ *
+ * Returns 0 on success, or WIMLIB_ERR_UNSUPPORTED if size overflows 32 bits.
+ */
+static int
+calculate_wimoverlay_dat_size(const struct WimOverlay_dat_header *old_hdr,
+                             u32 new_entry_2_size, u32 *size_ret)
+{
+       u64 size_64;
+       u32 size;
+
+       size_64 = sizeof(struct WimOverlay_dat_header);
+       if (old_hdr) {
+               for (u32 i = 0; i < old_hdr->num_entries_1; i++) {
+                       size_64 += sizeof(struct WimOverlay_dat_entry_1);
+                       size_64 += old_hdr->entry_1s[i].entry_2_length;
+               }
+       }
+       size_64 += sizeof(struct WimOverlay_dat_entry_1);
+       size_64 += new_entry_2_size;
+
+       size = size_64;
+       if (size_64 != size)
                return WIMLIB_ERR_UNSUPPORTED;
+
+       *size_ret = size;
+       return 0;
+}
+
+/*
+ * Writes @size bytes of @contents to the named file @path.
+ *
+ * Returns 0 on success; WIMLIB_ERR_OPEN or WIMLIB_ERR_WRITE on failure.
+ */
+static int
+write_wimoverlay_dat(const wchar_t *path, const void *contents, u32 size)
+{
+       HANDLE h;
+       DWORD bytes_written;
+
+       h = CreateFile(path, GENERIC_WRITE, 0, NULL,
+                      CREATE_ALWAYS, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+       if (h == INVALID_HANDLE_VALUE) {
+               win32_error(GetLastError(),
+                           L"\"%ls\": Can't open file for writing", path);
+               return WIMLIB_ERR_OPEN;
+       }
+
+       SetLastError(0);
+       if (!WriteFile(h, contents, size, &bytes_written, NULL) ||
+           bytes_written != size)
+       {
+               win32_error(GetLastError(),
+                           L"\"%ls\": Can't write file", path);
+               CloseHandle(h);
+               return WIMLIB_ERR_WRITE;
+       }
+
+       if (!CloseHandle(h)) {
+               win32_error(GetLastError(),
+                           L"\"%ls\": Can't close handle", path);
+               return WIMLIB_ERR_WRITE;
        }
 
-       wsprintf(drive_path, L"\\\\.\\%lc:", file_abspath[0]);
-       FREE(file_abspath);
        return 0;
 }
 
-/* Try to attach an instance of the Windows Overlay File System Filter Driver to
- * the specified drive (such as C:)  */
-static bool
-try_to_attach_wof(const wchar_t *drive)
+/*
+ * Generates the contents of WimOverlay.dat in memory, with one entry added.
+ *
+ * @buf
+ *     Buffer large enough to hold the new contents.
+ * @old_hdr
+ *     Old contents of WimOverlay.dat, or NULL if it did not exist.
+ * @wim_path
+ *     Absolute path to the WIM file.  It must begin with a drive letter; for
+ *     example, D:\install.wim.
+ * @wim_guid
+ *     GUID of the WIM, from the WIM header.
+ * @image
+ *     Number of the image in the WIM to specify in the new entry.
+ * @new_data_source_id
+ *     Data source ID to use for the new entry.
+ * @part_info
+ *     Partition information for the WIM file.
+ * @disk_info
+ *     Disk information for the WIM file.
+ * @new_entry_2_size
+ *     Size, in bytes, of the new location information structure ('struct
+ *     WimOverlay_dat_entry_2').
+ *
+ * Returns a pointer one past the last byte of @buf filled in.
+ */
+static u8 *
+fill_in_wimoverlay_dat(u8 *buf,
+                      const struct WimOverlay_dat_header *old_hdr,
+                      const wchar_t *wim_path,
+                      const u8 wim_guid[GUID_SIZE],
+                      int image,
+                      u64 new_data_source_id,
+                      const PARTITION_INFORMATION_EX *part_info,
+                      const DRIVE_LAYOUT_INFORMATION_EX *disk_info,
+                      u32 new_entry_2_size)
 {
-       HMODULE fltlib;
-       bool retval = false;
+       struct WimOverlay_dat_header *new_hdr;
+       struct WimOverlay_dat_entry_1 *new_entry_1;
+       struct WimOverlay_dat_entry_2 *new_entry_2;
+       u32 entry_2_offset;
+       u8 *p = buf;
 
-       /* Use FilterAttach() from Fltlib.dll.  */
+       new_hdr = (struct WimOverlay_dat_header *)p;
 
-       fltlib = LoadLibrary(L"Fltlib.dll");
+       /* Fill in new header  */
+       new_hdr->magic = WIMOVERLAY_DAT_MAGIC;
+       new_hdr->wim_provider_version = WIM_PROVIDER_CURRENT_VERSION;
+       new_hdr->unknown_0x08 = 0x00000028;
+       new_hdr->num_entries_1 = (old_hdr ? old_hdr->num_entries_1 : 0) + 1;
+       new_hdr->num_entries_2 = (old_hdr ? old_hdr->num_entries_2 : 0) + 1;
+       new_hdr->unknown_0x14 = 0x00000000;
 
-       if (!fltlib) {
-               WARNING("Failed to load Fltlib.dll");
-               return retval;
+       p += sizeof(struct WimOverlay_dat_header);
+
+       /* Copy WIM-specific information for old entries  */
+       entry_2_offset = sizeof(struct WimOverlay_dat_header) +
+                       (new_hdr->num_entries_1 * sizeof(struct WimOverlay_dat_entry_1));
+       if (old_hdr) {
+               for (u32 i = 0; i < old_hdr->num_entries_1; i++) {
+                       new_entry_1 = (struct WimOverlay_dat_entry_1 *)p;
+
+                       p = mempcpy(p, &old_hdr->entry_1s[i],
+                                   sizeof(struct WimOverlay_dat_entry_1));
+
+                       new_entry_1->entry_2_offset = entry_2_offset;
+                       entry_2_offset += new_entry_1->entry_2_length;
+               }
        }
 
-       HRESULT (WINAPI *func_FilterAttach)(LPCWSTR lpFilterName,
-                                           LPCWSTR lpVolumeName,
-                                           LPCWSTR lpInstanceName,
-                                           DWORD dwCreatedInstanceNameLength,
-                                           LPWSTR lpCreatedInstanceName);
+       /* Generate WIM-specific information for new entry  */
+       new_entry_1 = (struct WimOverlay_dat_entry_1 *)p;
 
-       func_FilterAttach = (void *)GetProcAddress(fltlib, "FilterAttach");
+       new_entry_1->data_source_id = new_data_source_id;
+       new_entry_1->entry_2_offset = entry_2_offset;
+       new_entry_1->entry_2_length = new_entry_2_size;
+       new_entry_1->wim_type = WIM_BOOT_NOT_OS_WIM;
+       new_entry_1->wim_index = image;
+       STATIC_ASSERT(sizeof(new_entry_1->guid) == GUID_SIZE);
+       copy_guid(new_entry_1->guid, wim_guid);
 
-       if (func_FilterAttach) {
-               HRESULT res;
+       p += sizeof(struct WimOverlay_dat_entry_1);
 
-               res = (*func_FilterAttach)(L"WoF", drive, NULL, 0, NULL);
+       /* Copy WIM location information for old entries  */
+       if (old_hdr) {
+               for (u32 i = 0; i < old_hdr->num_entries_1; i++) {
+                       wimlib_assert(new_hdr->entry_1s[i].entry_2_offset == p - buf);
+                       wimlib_assert(old_hdr->entry_1s[i].entry_2_length ==
+                                     new_hdr->entry_1s[i].entry_2_length);
+                       p = mempcpy(p,
+                                   ((const u8 *)old_hdr + old_hdr->entry_1s[i].entry_2_offset),
+                                   old_hdr->entry_1s[i].entry_2_length);
+               }
+       }
+
+       /* Generate WIM location information for new entry  */
+       new_entry_2 = (struct WimOverlay_dat_entry_2 *)p;
 
-               if (res == S_OK)
-                       retval = true;
+       new_entry_2->unknown_0x00 = 0x00000000;
+       new_entry_2->unknown_0x04 = 0x00000000;
+       new_entry_2->entry_2_length = new_entry_2_size;
+       new_entry_2->unknown_0x0C = 0x00000000;
+       new_entry_2->unknown_0x10 = 0x00000005;
+       new_entry_2->unknown_0x14 = 0x00000001;
+       new_entry_2->inner_struct_size = new_entry_2_size - 0x14;
+       new_entry_2->unknown_0x1C = 0x00000005;
+       new_entry_2->unknown_0x20 = 0x00000006;
+       new_entry_2->unknown_0x24 = 0x00000000;
+       new_entry_2->unknown_0x28 = 0x00000048;
+       new_entry_2->unknown_0x2C = 0x00000000;
+       new_entry_2->unknown_0x40 = 0x00000000;
+
+       if (part_info->PartitionStyle == PARTITION_STYLE_MBR) {
+               new_entry_2->partition.mbr.part_start_offset = part_info->StartingOffset.QuadPart;
+               new_entry_2->partition.mbr.padding = 0;
+               new_entry_2->partition_table_type = WIMOVERLAY_PARTITION_TYPE_MBR;
+               new_entry_2->disk.mbr.disk_id = disk_info->Mbr.Signature;
+               new_entry_2->disk.mbr.padding[0] = 0x00000000;
+               new_entry_2->disk.mbr.padding[1] = 0x00000000;
+               new_entry_2->disk.mbr.padding[2] = 0x00000000;
        } else {
-               WARNING("FilterAttach() does not exist in Fltlib.dll");
+               STATIC_ASSERT(sizeof(new_entry_2->partition.gpt.part_unique_guid) ==
+                             sizeof(part_info->Gpt.PartitionId));
+               memcpy(new_entry_2->partition.gpt.part_unique_guid,
+                      &part_info->Gpt.PartitionId,
+                      sizeof(part_info->Gpt.PartitionId));
+               new_entry_2->partition_table_type = WIMOVERLAY_PARTITION_TYPE_GPT;
+
+               STATIC_ASSERT(sizeof(new_entry_2->disk.gpt.disk_guid) ==
+                             sizeof(disk_info->Gpt.DiskId));
+               memcpy(new_entry_2->disk.gpt.disk_guid,
+                      &disk_info->Gpt.DiskId,
+                      sizeof(disk_info->Gpt.DiskId));
+
+               STATIC_ASSERT(sizeof(new_entry_2->disk.gpt.disk_guid) ==
+                             sizeof(new_entry_2->partition.gpt.part_unique_guid));
+       }
+       new_entry_2->unknown_0x58[0] = 0x00000000;
+       new_entry_2->unknown_0x58[1] = 0x00000000;
+       new_entry_2->unknown_0x58[2] = 0x00000000;
+       new_entry_2->unknown_0x58[3] = 0x00000000;
+
+       wimlib_assert(wim_path[2] == L'\\');
+       return mempcpy(new_entry_2->wim_file_name,
+                      wim_path + 2,
+                      new_entry_2_size - sizeof(struct WimOverlay_dat_entry_2));
+}
+
+/*
+ * Prepares the new contents of WimOverlay.dat in memory, with one entry added.
+ *
+ * @old_hdr
+ *     Old contents of WimOverlay.dat, or NULL if it did not exist.
+ * @wim_path
+ *     Absolute path to the WIM file.  It must begin with a drive letter; for
+ *     example, D:\install.wim.
+ * @wim_guid
+ *     GUID of the WIM, from the WIM header.
+ * @image
+ *     Number of the image in the WIM to specify in the new entry.
+ * @new_contents_ret
+ *     Location into which to return the new contents as a malloc()ed buffer on
+ *     success.
+ * @new_contents_size_ret
+ *     Location into which to return the size, in bytes, of the new contents on
+ *     success.
+ * @new_data_source_id_ret
+ *     Location into which to return the data source ID of the new entry on
+ *     success.
+ *
+ * Returns 0 on success, or a positive error code on failure.
+ */
+static int
+prepare_wimoverlay_dat(const struct WimOverlay_dat_header *old_hdr,
+                      const wchar_t *wim_path,
+                      const u8 wim_guid[GUID_SIZE],
+                      int image,
+                      void **new_contents_ret,
+                      u32 *new_contents_size_ret,
+                      u64 *new_data_source_id_ret)
+{
+       int ret;
+       PARTITION_INFORMATION_EX part_info;
+       DRIVE_LAYOUT_INFORMATION_EX disk_info;
+       u64 new_data_source_id;
+       u32 new_entry_2_size;
+       u32 new_contents_size;
+       u8 *buf;
+       u8 *end;
+
+       ret = query_partition_and_disk_info(wim_path, &part_info, &disk_info);
+       if (ret)
+               return ret;
+
+       new_data_source_id = alloc_new_data_source_id(old_hdr);
+
+       new_entry_2_size = sizeof(struct WimOverlay_dat_entry_2) +
+                               ((wcslen(wim_path) - 2 + 1) * sizeof(wchar_t));
+       ret = calculate_wimoverlay_dat_size(old_hdr, new_entry_2_size,
+                                           &new_contents_size);
+       if (ret)
+               return ret;
+
+       buf = MALLOC(new_contents_size);
+       if (!buf)
+               return WIMLIB_ERR_NOMEM;
+
+       end = fill_in_wimoverlay_dat(buf, old_hdr, wim_path, wim_guid, image,
+                                    new_data_source_id,
+                                    &part_info, &disk_info, new_entry_2_size);
+
+       wimlib_assert(end - buf == new_contents_size);
+
+       *new_contents_ret = buf;
+       *new_contents_size_ret = new_contents_size;
+       *new_data_source_id_ret = new_data_source_id;
+       return 0;
+}
+
+/*
+ * Reads and validates a WimOverlay.dat file.
+ *
+ * @path
+ *     Path to the WimOverlay.dat file, such as
+ *     C:\System Volume Information\WimOverlay.dat
+ * @contents_ret
+ *     Location into which to return the contents as a malloc()ed buffer on
+ *     success.  This can be cast to 'struct WimOverlay_dat_header', and its
+ *     contents are guaranteed to be valid.  Alternatively, if the file does
+ *     not exist, NULL will be returned here.
+ *
+ * Returns 0 on success, or a positive error code on failure.
+ */
+static int
+read_wimoverlay_dat(const wchar_t *path, void **contents_ret)
+{
+       HANDLE h;
+       BY_HANDLE_FILE_INFORMATION info;
+       int ret;
+       void *contents;
+       const struct WimOverlay_dat_header *hdr;
+       DWORD bytes_read;
+       bool already_retried = false;
+
+retry:
+       h = open_file(path, GENERIC_READ);
+       if (h == INVALID_HANDLE_VALUE) {
+               DWORD err = GetLastError();
+               if (err == ERROR_FILE_NOT_FOUND) {
+                       *contents_ret = NULL;
+                       return 0;
+               }
+               if (err == ERROR_PATH_NOT_FOUND &&
+                   func_RtlCreateSystemVolumeInformationFolder)
+               {
+                       wchar_t volume_root_path[] = L"\\??\\X:\\";
+
+                       *(wcschr(volume_root_path, L'X')) = path[0];
+
+                       UNICODE_STRING str = {
+                               .Length = sizeof(volume_root_path) - sizeof(wchar_t),
+                               .MaximumLength = sizeof(volume_root_path),
+                               .Buffer = volume_root_path,
+                       };
+                       NTSTATUS status;
+                       DWORD err2;
+
+                       status = (*func_RtlCreateSystemVolumeInformationFolder)(&str);
+
+                       err2 = RtlNtStatusToDosError(status);
+                       if (err2 == ERROR_SUCCESS) {
+                               if (!already_retried) {
+                                       already_retried = true;
+                                       goto retry;
+                               }
+                       } else {
+                               err = err2;
+                       }
+               }
+               win32_error(err, L"\"%ls\": Can't open for reading", path);
+               return WIMLIB_ERR_OPEN;
+       }
+       if (!GetFileInformationByHandle(h, &info)) {
+               win32_error(GetLastError(), L"\"%ls\": Can't query metadata", path);
+               CloseHandle(h);
+               return WIMLIB_ERR_STAT;
        }
 
-       FreeLibrary(fltlib);
+       contents = NULL;
+       if (!info.nFileSizeHigh)
+               contents = MALLOC(info.nFileSizeLow);
+       if (!contents) {
+               ERROR("\"%ls\": File is too large to fit into memory", path);
+               CloseHandle(h);
+               return WIMLIB_ERR_NOMEM;
+       }
 
-       return retval;
+       SetLastError(0);
+       if (!ReadFile(h, contents, info.nFileSizeLow, &bytes_read, NULL) ||
+           bytes_read != info.nFileSizeLow)
+       {
+               win32_error(GetLastError(), L"\"%ls\": Can't read data", path);
+               CloseHandle(h);
+               ret = WIMLIB_ERR_READ;
+               goto out_free_contents;
+       }
+
+       CloseHandle(h);
+
+       if (info.nFileSizeLow < sizeof(struct WimOverlay_dat_header)) {
+               ERROR("\"%ls\": File is unexpectedly small (only %"PRIu32" bytes)",
+                     path, (u32)info.nFileSizeLow);
+               ret = WIMLIB_ERR_UNSUPPORTED;
+               goto out_free_contents;
+       }
+
+       hdr = (const struct WimOverlay_dat_header *)contents;
+
+       if (hdr->magic != WIMOVERLAY_DAT_MAGIC ||
+           hdr->wim_provider_version != WIM_PROVIDER_CURRENT_VERSION ||
+           hdr->unknown_0x08 != 0x00000028 ||
+           (hdr->num_entries_1 != hdr->num_entries_2) ||
+           hdr->unknown_0x14 != 0x00000000)
+       {
+               ERROR("\"%ls\": Header contains unexpected data:", path);
+               if (wimlib_print_errors) {
+                       print_byte_field((const u8 *)hdr,
+                                        sizeof(struct WimOverlay_dat_header),
+                                        wimlib_error_file);
+                       fputc('\n', wimlib_error_file);
+               }
+               ret = WIMLIB_ERR_UNSUPPORTED;
+               goto out_free_contents;
+       }
+
+       if ((u64)hdr->num_entries_1 * sizeof(struct WimOverlay_dat_entry_1) >
+           info.nFileSizeLow - sizeof(struct WimOverlay_dat_header))
+       {
+               ERROR("\"%ls\": File is unexpectedly small "
+                     "(only %"PRIu32" bytes, but has %"PRIu32" entries)",
+                     path, (u32)info.nFileSizeLow, hdr->num_entries_1);
+               ret = WIMLIB_ERR_UNSUPPORTED;
+               goto out_free_contents;
+       }
+
+       for (u32 i = 0; i < hdr->num_entries_1; i++) {
+               const struct WimOverlay_dat_entry_1 *entry_1;
+               const struct WimOverlay_dat_entry_2 *entry_2;
+               u32 wim_file_name_length;
+
+               entry_1 = &hdr->entry_1s[i];
+
+               if (((u64)entry_1->entry_2_offset +
+                    (u64)entry_1->entry_2_length) >
+                   info.nFileSizeLow)
+               {
+                       ERROR("\"%ls\": entry %"PRIu32" (2) "
+                             "(data source ID 0x%016"PRIx64") "
+                             "overflows file",
+                             path, i, entry_1->data_source_id);
+                       ret = WIMLIB_ERR_UNSUPPORTED;
+                       goto out_free_contents;
+               }
+               if (entry_1->entry_2_length < sizeof(struct WimOverlay_dat_entry_2)) {
+                       ERROR("\"%ls\": entry %"PRIu32" (2) "
+                             "(data source ID 0x%016"PRIx64") "
+                             "is too short",
+                             path, i, entry_1->data_source_id);
+                       ret = WIMLIB_ERR_UNSUPPORTED;
+                       goto out_free_contents;
+               }
+
+               if (entry_1->entry_2_offset % 2 != 0) {
+                       ERROR("\"%ls\": entry %"PRIu32" (2) "
+                             "(data source ID 0x%016"PRIx64") "
+                             "is misaligned",
+                             path, i, entry_1->data_source_id);
+                       ret = WIMLIB_ERR_UNSUPPORTED;
+                       goto out_free_contents;
+               }
+
+               entry_2 = (const struct WimOverlay_dat_entry_2 *)
+                               ((const u8 *)hdr + entry_1->entry_2_offset);
+
+               wim_file_name_length = entry_1->entry_2_length -
+                                       sizeof(struct WimOverlay_dat_entry_2);
+               if ((wim_file_name_length < 2 * sizeof(wchar_t)) ||
+                   (wim_file_name_length % sizeof(wchar_t) != 0) ||
+                   (wmemchr(entry_2->wim_file_name, L'\0',
+                            wim_file_name_length / sizeof(wchar_t))
+                    != &entry_2->wim_file_name[wim_file_name_length /
+                                               sizeof(wchar_t) - 1]))
+               {
+                       ERROR("\"%ls\": entry %"PRIu32" (2) "
+                             "(data source ID 0x%016"PRIx64") "
+                             "has invalid WIM file name",
+                             path, i, entry_1->data_source_id);
+                       if (wimlib_print_errors) {
+                               print_byte_field((const u8 *)entry_2->wim_file_name,
+                                                wim_file_name_length,
+                                                wimlib_error_file);
+                               fputc('\n', wimlib_error_file);
+                       }
+                       ret = WIMLIB_ERR_UNSUPPORTED;
+                       goto out_free_contents;
+               }
+
+               if (entry_2->unknown_0x00 != 0x00000000 ||
+                   entry_2->unknown_0x04 != 0x00000000 ||
+                   entry_2->unknown_0x0C != 0x00000000 ||
+                   entry_2->entry_2_length != entry_1->entry_2_length ||
+                   entry_2->unknown_0x10 != 0x00000005 ||
+                   entry_2->unknown_0x14 != 0x00000001 ||
+                   entry_2->inner_struct_size != entry_1->entry_2_length - 0x14 ||
+                   entry_2->unknown_0x1C != 0x00000005 ||
+                   entry_2->unknown_0x20 != 0x00000006 ||
+                   entry_2->unknown_0x24 != 0x00000000 ||
+                   entry_2->unknown_0x28 != 0x00000048 ||
+                   entry_2->unknown_0x2C != 0x00000000 ||
+                   entry_2->unknown_0x40 != 0x00000000 ||
+                   (entry_2->partition_table_type != WIMOVERLAY_PARTITION_TYPE_GPT &&
+                    entry_2->partition_table_type != WIMOVERLAY_PARTITION_TYPE_MBR) ||
+                   (entry_2->partition_table_type == WIMOVERLAY_PARTITION_TYPE_MBR &&
+                    entry_2->partition.mbr.padding != 0) ||
+                   (entry_2->partition_table_type == WIMOVERLAY_PARTITION_TYPE_GPT &&
+                    entry_2->partition.mbr.padding == 0) ||
+                   entry_2->unknown_0x58[0] != 0x00000000 ||
+                   entry_2->unknown_0x58[1] != 0x00000000 ||
+                   entry_2->unknown_0x58[2] != 0x00000000 ||
+                   entry_2->unknown_0x58[3] != 0x00000000)
+               {
+                       ERROR("\"%ls\": entry %"PRIu32" (2) "
+                             "(data source ID 0x%016"PRIx64") "
+                             "contains unexpected data!",
+                             path, i, entry_1->data_source_id);
+                       if (wimlib_print_errors) {
+                               print_byte_field((const u8 *)entry_2,
+                                                entry_1->entry_2_length,
+                                                wimlib_error_file);
+                               fputc('\n', wimlib_error_file);
+                       }
+                       ret = WIMLIB_ERR_UNSUPPORTED;
+                       goto out_free_contents;
+               }
+       }
+
+       *contents_ret = contents;
+       return 0;
+
+out_free_contents:
+       FREE(contents);
+       return ret;
+}
+
+/*
+ * Update WimOverlay.dat manually in order to add a WIM data source to the
+ * target volume.
+ *
+ * THIS CODE IS EXPERIMENTAL AS I HAD TO REVERSE ENGINEER THE FILE FORMAT!
+ *
+ * @path
+ *     Target drive.  Must be a letter followed by a colon (e.g. D:).
+ * @wim_path
+ *     Absolute path to the WIM file.  It must begin with a drive letter; for
+ *     example, D:\install.wim.
+ * @wim_guid
+ *     GUID of the WIM, from the WIM header.
+ * @image
+ *     Number of the image in the WIM to specify in the new entry.
+ * @data_source_id_ret
+ *     On success, the allocated data source ID is returned here.
+ */
+static int
+update_wimoverlay_manually(const wchar_t *drive, const wchar_t *wim_path,
+                          const u8 wim_guid[GUID_SIZE],
+                          int image, u64 *data_source_id_ret)
+{
+       wchar_t path_main[] = L"A:\\System Volume Information\\WimOverlay.dat";
+       wchar_t path_backup[] = L"A:\\System Volume Information\\WimOverlay.backup";
+       wchar_t path_wimlib_backup[] = L"A:\\System Volume Information\\WimOverlay.wimlib_backup";
+       wchar_t path_new[] = L"A:\\System Volume Information\\WimOverlay.wimlib_new";
+       void *old_contents = NULL;
+       void *new_contents = NULL;
+       u32 new_contents_size = 0;
+       u64 new_data_source_id = -1;
+       int ret;
+
+       wimlib_assert(drive[0] != L'\0' &&
+                     drive[1] == L':' &&
+                     drive[2] == L'\0');
+
+       path_main[0]          = drive[0];
+       path_backup[0]        = drive[0];
+       path_wimlib_backup[0] = drive[0];
+       path_new[0]           = drive[0];
+
+       ret = read_wimoverlay_dat(path_main, &old_contents);
+       if (ret)
+               goto out;
+
+       ret = prepare_wimoverlay_dat(old_contents, wim_path, wim_guid, image,
+                                    &new_contents, &new_contents_size,
+                                    &new_data_source_id);
+       FREE(old_contents);
+       if (ret)
+               goto out;
+
+       /* Write WimOverlay.wimlib_new  */
+       ret = write_wimoverlay_dat(path_new,
+                                  new_contents, new_contents_size);
+       if (ret)
+               goto out_free_new_contents;
+
+       /* Write WimOverlay.backup  */
+       ret = write_wimoverlay_dat(path_backup,
+                                  new_contents, new_contents_size);
+       if (ret)
+               goto out_free_new_contents;
+
+       if (old_contents) {
+               /* Rename WimOverlay.dat => WimOverlay.wimlib_backup  */
+               ret = win32_rename_replacement(path_main, path_wimlib_backup);
+               if (ret) {
+                       ERROR_WITH_ERRNO("Can't rename \"%ls\" => \"%ls\"",
+                                        path_main, path_wimlib_backup);
+                       ret = WIMLIB_ERR_RENAME;
+                       goto out_free_new_contents;
+               }
+       }
+
+       /* Rename WimOverlay.wimlib_new => WimOverlay.dat  */
+       ret = win32_rename_replacement(path_new, path_main);
+       if (ret) {
+               ERROR_WITH_ERRNO("Can't rename \"%ls\" => \"%ls\"",
+                                path_new, path_main);
+               ret = WIMLIB_ERR_RENAME;
+       }
+out_free_new_contents:
+       FREE(new_contents);
+out:
+       if (ret == WIMLIB_ERR_UNSUPPORTED) {
+               ERROR("Please report to developer ("PACKAGE_BUGREPORT").\n"
+                     "        If possible send the file \"%ls\".\n\n", path_main);
+       }
+       if (ret == 0)
+               *data_source_id_ret = new_data_source_id;
+       return ret;
 }
 
 /*
@@ -112,10 +872,12 @@ try_to_attach_wof(const wchar_t *drive)
  * @wim_path
  *     Absolute path to the WIM file.  This must include a drive letter and use
  *     backslash path separators.
+ * @wim_guid
+ *     GUID of the WIM, from the WIM header.
  * @image
- *     Index of the image in the WIM being applied.
+ *     Number of the image in the WIM being applied.
  * @target
- *     Path to the target drive.
+ *     Path to the target directory.
  * @data_source_id_ret
  *     On success, an identifier for the backing WIM file will be returned
  *     here.
@@ -123,8 +885,10 @@ try_to_attach_wof(const wchar_t *drive)
  * Returns 0 on success, or a positive error code on failure.
  */
 int
-wimboot_alloc_data_source_id(const wchar_t *wim_path, int image,
-                            const wchar_t *target, u64 *data_source_id_ret)
+wimboot_alloc_data_source_id(const wchar_t *wim_path,
+                            const u8 wim_guid[GUID_SIZE],
+                            int image, const wchar_t *target,
+                            u64 *data_source_id_ret, bool *wof_running_ret)
 {
        tchar drive_path[7];
        size_t wim_path_nchars;
@@ -176,13 +940,11 @@ wimboot_alloc_data_source_id(const wchar_t *wim_path, int image,
        wmemcpy(&wim_info->wim_file_name[prefix_nchars], wim_path, wim_path_nchars);
 
 retry_ioctl:
-       h = CreateFile(drive_path, GENERIC_WRITE,
-                      FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
-                      NULL, OPEN_EXISTING, 0, NULL);
+       h = open_file(drive_path, GENERIC_WRITE);
 
        if (h == INVALID_HANDLE_VALUE) {
-               set_errno_from_GetLastError();
-               ERROR_WITH_ERRNO("Failed to open \"%ls\"", drive_path + 4);
+               win32_error(GetLastError(),
+                           L"Failed to open \"%ls\"", drive_path + 4);
                ret = WIMLIB_ERR_OPEN;
                goto out_free_in;
        }
@@ -198,27 +960,20 @@ retry_ioctl:
                                CloseHandle(h);
                                h = INVALID_HANDLE_VALUE;
                                tried_to_attach_wof = true;
-                               if (try_to_attach_wof(drive_path + 4))
+                               if (win32_try_to_attach_wof(drive_path + 4))
                                        goto retry_ioctl;
                        }
-                       ERROR("The version of Windows you are running does not appear to support\n"
-                             "        the Windows Overlay File System Filter Driver.  Therefore, wimlib\n"
-                             "        cannot apply WIMBoot information.  Please run from Windows 8.1\n"
-                             "        Update 1 or later.");
                        ret = WIMLIB_ERR_UNSUPPORTED;
                        goto out_close_handle;
                } else {
-                       set_errno_from_win32_error(err);
-                       ERROR_WITH_ERRNO("Failed to add overlay source \"%ls\" "
-                                        "to volume \"%ls\" (err=0x%08"PRIu32")",
-                                        wim_path, drive_path + 4, (uint32_t)err);
+                       win32_error(err, L"Failed to add overlay source \"%ls\" "
+                                   "to volume \"%ls\"", wim_path, drive_path + 4);
                        ret = WIMLIB_ERR_WIMBOOT;
                        goto out_close_handle;
                }
        }
 
        if (bytes_returned != sizeof(data_source_id)) {
-               set_errno_from_win32_error(ERROR_INVALID_DATA);
                ret = WIMLIB_ERR_WIMBOOT;
                ERROR("Unexpected result size when adding "
                      "overlay source \"%ls\" to volume \"%ls\"",
@@ -226,6 +981,7 @@ retry_ioctl:
                goto out_close_handle;
        }
 
+       *wof_running_ret = true;
        *data_source_id_ret = data_source_id;
        ret = 0;
 
@@ -234,6 +990,21 @@ out_close_handle:
 out_free_in:
        FREE(in);
 out:
+       if (ret == WIMLIB_ERR_UNSUPPORTED) {
+       #if 0
+               WARNING(
+               "The version of Windows you are running does not appear to support\n"
+               "        the Windows Overlay File System Filter Driver.  This is normally\n"
+               "        available on Windows 8.1 Update 1 or later.  Therefore, wimlib\n"
+               "        will attempt to update the WimOverlay.dat file directly.\n");
+       #else
+               WARNING("WOF driver is not available; updating WimOverlay.dat directly.");
+       #endif
+               ret = update_wimoverlay_manually(drive_path + 4, wim_path,
+                                                wim_guid, image,
+                                                data_source_id_ret);
+               *wof_running_ret = false;
+       }
        return ret;
 }
 
@@ -241,55 +1012,130 @@ out:
 /*
  * Set WIMBoot information on the specified file.
  *
- * @path
- *     Path to extracted file (already created).
+ * This turns it into a reparse point that redirects accesses to it, to the
+ * corresponding resource in the WIM archive.
+ *
+ * @h
+ *     Open handle to the file, with GENERIC_WRITE access.
+ * @blob
+ *     The blob for the unnamed data stream of the file.
  * @data_source_id
- *     Identifier for backing WIM file.
- * @hash
- *     SHA-1 message digest of the file's unnamed data stream.
+ *     Allocated identifier for the WIM data source on the destination volume.
+ * @blob_table_hash
+ *     SHA-1 message digest of the WIM's blob table.
+ * @wof_running
+ *     %true if the WOF driver appears to be available and working; %false if
+ *     not.
  *
- * Returns 0 on success, or a positive error code on failure.
+ * Returns %true on success, or %false on failure with GetLastError() set.
  */
-int
-wimboot_set_pointer(const wchar_t *path, u64 data_source_id,
-                   const u8 hash[20])
+bool
+wimboot_set_pointer(HANDLE h,
+                   const struct blob_descriptor *blob,
+                   u64 data_source_id,
+                   const u8 blob_table_hash[SHA1_HASH_SIZE],
+                   bool wof_running)
 {
-       struct {
-               struct wof_external_info wof_info;
-               struct wim_provider_external_info wim_info;
-       } in;
-       HANDLE h;
        DWORD bytes_returned;
-       int ret;
 
-       in.wof_info.version = WOF_CURRENT_VERSION;
-       in.wof_info.provider = WOF_PROVIDER_WIM;
+       if (wof_running) {
+               /* The WOF driver is running.  We can create the reparse point
+                * using FSCTL_SET_EXTERNAL_BACKING.  */
+               unsigned int max_retries = 4;
+               struct {
+                       struct wof_external_info wof_info;
+                       struct wim_provider_external_info wim_info;
+               } in;
 
-       in.wim_info.version = WIM_PROVIDER_CURRENT_VERSION;
-       in.wim_info.flags = 0;
-       in.wim_info.data_source_id = data_source_id;
-       memcpy(in.wim_info.resource_hash, hash, 20);
+       retry:
+               memset(&in, 0, sizeof(in));
 
-       h = win32_open_existing_file(path, GENERIC_WRITE);
-       if (h == INVALID_HANDLE_VALUE) {
-               set_errno_from_GetLastError();
-               ret = WIMLIB_ERR_OPEN;
-               goto out;
-       }
+               in.wof_info.version = WOF_CURRENT_VERSION;
+               in.wof_info.provider = WOF_PROVIDER_WIM;
 
-       if (!DeviceIoControl(h, FSCTL_SET_EXTERNAL_BACKING,
-                            &in, sizeof(in), NULL, 0, &bytes_returned, NULL))
-       {
-               DWORD err = GetLastError();
-               set_errno_from_win32_error(err);
-               ERROR_WITH_ERRNO("\"%ls\": Couldn't set WIMBoot pointer data "
-                                "(err=0x%08x)", path, (uint32_t)err);
-               ret = WIMLIB_ERR_WIMBOOT;
-               goto out_close_handle;
+               in.wim_info.version = WIM_PROVIDER_CURRENT_VERSION;
+               in.wim_info.flags = 0;
+               in.wim_info.data_source_id = data_source_id;
+               copy_hash(in.wim_info.unnamed_data_stream_hash, blob->hash);
+
+               /* blob_table_hash is not necessary  */
+
+               if (!DeviceIoControl(h, FSCTL_SET_EXTERNAL_BACKING,
+                                    &in, sizeof(in), NULL, 0,
+                                    &bytes_returned, NULL))
+               {
+                       /* Try to track down sporadic errors  */
+                       if (wimlib_print_errors) {
+                               WARNING("FSCTL_SET_EXTERNAL_BACKING failed (err=%u); data was %zu bytes:",
+                                       (u32)GetLastError(), sizeof(in));
+                               print_byte_field((const u8 *)&in, sizeof(in), wimlib_error_file);
+                               putc('\n', wimlib_error_file);
+                       }
+                       if (--max_retries) {
+                               WARNING("Retrying after 100ms...");
+                               Sleep(100);
+                               goto retry;
+                       }
+                       WARNING("Too many retries; returning failure");
+                       return false;
+               }
+       } else {
+
+               /* The WOF driver is running.  We need to create the reparse
+                * point manually.  */
+
+               struct {
+                       struct {
+                               le32 rptag;
+                               le16 rpdatalen;
+                               le16 rpreserved;
+                       } hdr;
+                       struct wof_external_info wof_info;
+                       struct wim_provider_rpdata wim_info;
+               } in;
+
+               STATIC_ASSERT(sizeof(in) == 8 +
+                             sizeof(struct wof_external_info) +
+                             sizeof(struct wim_provider_rpdata));
+
+               in.hdr.rptag = WIM_IO_REPARSE_TAG_WOF;
+               in.hdr.rpdatalen = sizeof(in) - sizeof(in.hdr);
+               in.hdr.rpreserved = 0;
+
+               in.wof_info.version = WOF_CURRENT_VERSION;
+               in.wof_info.provider = WOF_PROVIDER_WIM;
+
+               in.wim_info.version = 2;
+               in.wim_info.flags = 0;
+               in.wim_info.data_source_id = data_source_id;
+               copy_hash(in.wim_info.unnamed_data_stream_hash, blob->hash);
+               copy_hash(in.wim_info.blob_table_hash, blob_table_hash);
+               in.wim_info.unnamed_data_stream_size = blob->size;
+               in.wim_info.unnamed_data_stream_size_in_wim = blob->rdesc->size_in_wim;
+               in.wim_info.unnamed_data_stream_offset_in_wim = blob->rdesc->offset_in_wim;
+
+               if (!DeviceIoControl(h, FSCTL_SET_REPARSE_POINT,
+                                    &in, sizeof(in), NULL, 0, &bytes_returned, NULL))
+                       return false;
+
+               /* We also need to create an unnamed data stream of the correct
+                * size.  Otherwise the file shows up as zero length.  It can be
+                * a sparse stream containing all zeroes; its contents
+                * are unimportant.  */
+               if (!DeviceIoControl(h, FSCTL_SET_SPARSE, NULL, 0, NULL, 0,
+                                    &bytes_returned, NULL))
+                       return false;
+
+               if (!SetFilePointerEx(h,
+                                     (LARGE_INTEGER){ .QuadPart = blob->size},
+                                     NULL, FILE_BEGIN))
+                       return false;
+
+               if (!SetEndOfFile(h))
+                       return false;
        }
-       ret = 0;
-out_close_handle:
-       CloseHandle(h);
-out:
-       return ret;
+
+       return true;
 }
+
+#endif /* __WIN32__ */