]> wimlib.net Git - wimlib/blobdiff - src/win32_apply.c
win32_common: add winnt_fsctl() helper method
[wimlib] / src / win32_apply.c
index 49e25d4b50bd30d156b6a669cd0f6a9f6ab0d0a1..afa11ac76b160c82aec401360d907245aefc7fbf 100644 (file)
@@ -3,7 +3,7 @@
  */
 
 /*
- * Copyright (C) 2013, 2014, 2015 Eric Biggers
+ * Copyright (C) 2013-2016 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
@@ -41,6 +41,7 @@
 #include "wimlib/textfile.h"
 #include "wimlib/xml.h"
 #include "wimlib/wimboot.h"
+#include "wimlib/wof.h"
 
 struct win32_apply_ctx {
 
@@ -59,17 +60,18 @@ struct win32_apply_ctx {
                        u8 blob_table_hash[SHA1_HASH_SIZE];
                } *wims;
                size_t num_wims;
-               struct string_set *prepopulate_pats;
-               void *mem_prepopulate_pats;
                bool wof_running;
-               bool tried_to_load_prepopulate_list;
-
                bool have_wrong_version_wims;
                bool have_uncompressed_wims;
                bool have_unsupported_compressed_resources;
                bool have_huge_resources;
        } wimboot;
 
+       /* External backing information  */
+       struct string_set *prepopulate_pats;
+       void *mem_prepopulate_pats;
+       bool tried_to_load_prepopulate_list;
+
        /* Open handle to the target directory  */
        HANDLE h_target;
 
@@ -146,6 +148,20 @@ struct win32_apply_ctx {
        /* 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;
+
+       /* 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;
@@ -208,6 +224,14 @@ get_vol_flags(const wchar_t *target, DWORD *vol_flags_ret,
        }
 }
 
+/* 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);
 
@@ -243,9 +267,10 @@ win32_get_supported_features(const wchar_t *target,
 
        get_vol_flags(target, &vol_flags, &short_names_supported);
 
-       supported_features->archive_files = 1;
+       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;
@@ -282,8 +307,22 @@ win32_get_supported_features(const wchar_t *target,
        return 0;
 }
 
-/* Load the patterns from [PrepopulateList] of WimBootCompress.ini in the WIM
- * image being extracted.  */
+#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)
 {
@@ -296,7 +335,10 @@ load_prepopulate_pats(struct win32_apply_ctx *ctx)
        void *mem;
        struct text_file_section sec;
 
-       ctx->wimboot.tried_to_load_prepopulate_list = true;
+       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 ||
@@ -330,14 +372,14 @@ load_prepopulate_pats(struct win32_apply_ctx *ctx)
                                LOAD_TEXT_FILE_REMOVE_QUOTES |
                                        LOAD_TEXT_FILE_NO_WARNINGS,
                                mangle_pat);
-       BUILD_BUG_ON(OS_PREFERRED_PATH_SEPARATOR != WIM_PATH_SEPARATOR);
+       STATIC_ASSERT(OS_PREFERRED_PATH_SEPARATOR == WIM_PATH_SEPARATOR);
        FREE(buf);
        if (ret) {
                FREE(s);
                return ret;
        }
-       ctx->wimboot.prepopulate_pats = s;
-       ctx->wimboot.mem_prepopulate_pats = mem;
+       ctx->prepopulate_pats = s;
+       ctx->mem_prepopulate_pats = mem;
        return 0;
 }
 
@@ -348,8 +390,7 @@ 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->wimboot.prepopulate_pats &&
-           match_pattern_list(path, ctx->wimboot.prepopulate_pats))
+       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
@@ -367,6 +408,8 @@ can_externally_back_path(const wchar_t *path, const struct win32_apply_ctx *ctx)
        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)
@@ -436,18 +479,38 @@ is_resource_valid_for_external_backing(const struct wim_resource_descriptor *rde
        return true;
 }
 
-#define WIM_BACKING_NOT_ENABLED                -1
-#define WIM_BACKING_NOT_POSSIBLE       -2
-#define WIM_BACKING_EXCLUDED           -3
+#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)
+                          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;
 
@@ -459,13 +522,17 @@ will_externally_back_inode(struct wim_inode *inode, struct win32_apply_ctx *ctx,
        if (inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
                                   FILE_ATTRIBUTE_REPARSE_POINT |
                                   FILE_ATTRIBUTE_ENCRYPTED))
-               return WIM_BACKING_NOT_POSSIBLE;
+               return EXTERNAL_BACKING_NOT_POSSIBLE;
 
        blob = inode_get_blob_for_unnamed_data_stream_resolved(inode);
 
-       if (!blob || blob->blob_location != BLOB_IN_WIM ||
-           !is_resource_valid_for_external_backing(blob->rdesc, ctx))
-               return WIM_BACKING_NOT_POSSIBLE;
+       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
@@ -481,7 +548,7 @@ will_externally_back_inode(struct wim_inode *inode, struct win32_apply_ctx *ctx,
                if (!can_externally_back_path(dentry->d_full_path, ctx)) {
                        if (excluded_dentry_ret)
                                *excluded_dentry_ret = dentry;
-                       return WIM_BACKING_EXCLUDED;
+                       return EXTERNAL_BACKING_EXCLUDED;
                }
        }
 
@@ -490,22 +557,19 @@ will_externally_back_inode(struct wim_inode *inode, struct win32_apply_ctx *ctx,
 }
 
 /*
- * Determines if the unnamed data stream of a file will be created as an
- * external backing, as opposed to a standard extraction.
+ * 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_externally_back(struct wim_dentry *dentry, struct apply_ctx *_ctx)
+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 WIM_BACKING_NOT_ENABLED;
+               return EXTERNAL_BACKING_NOT_ENABLED;
 
-       if (!ctx->wimboot.tried_to_load_prepopulate_list)
-               if (load_prepopulate_pats(ctx) == WIMLIB_ERR_NOMEM)
-                       return WIMLIB_ERR_NOMEM;
-
-       return will_externally_back_inode(dentry->d_inode, ctx, NULL);
+       return will_externally_back_inode(dentry->d_inode, ctx, NULL, true);
 }
 
 /* Find the WOF registration information for the specified WIM file.  */
@@ -521,21 +585,21 @@ find_wimboot_wim(WIMStruct *wim_to_find, struct win32_apply_ctx *ctx)
 }
 
 static int
-set_external_backing(HANDLE h, struct wim_inode *inode, struct win32_apply_ctx *ctx)
+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);
+       ret = will_externally_back_inode(inode, ctx, &excluded_dentry, true);
        if (ret > 0) /* Error.  */
                return ret;
 
-       if (ret < 0 && ret != WIM_BACKING_EXCLUDED)
+       if (ret < 0 && ret != EXTERNAL_BACKING_EXCLUDED)
                return 0; /* Not externally backing, other than due to exclusion.  */
 
-       if (unlikely(ret == WIM_BACKING_EXCLUDED)) {
+       if (unlikely(ret == EXTERNAL_BACKING_EXCLUDED)) {
                /* Not externally backing due to exclusion.  */
                union wimlib_progress_info info;
 
@@ -615,8 +679,7 @@ register_wim_with_wof(WIMStruct *wim, struct win32_apply_ctx *ctx)
        return 0;
 }
 
-/* Prepare for doing a "WIMBoot" extraction by loading patterns from
- * [PrepopulateList] of WimBootCompress.ini and registering each source WIM file
+/* 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)
@@ -624,12 +687,8 @@ start_wimboot_extraction(struct list_head *dentry_list, struct win32_apply_ctx *
        int ret;
        struct wim_dentry *dentry;
 
-       if (!ctx->wimboot.tried_to_load_prepopulate_list)
-               if (load_prepopulate_pats(ctx) == WIMLIB_ERR_NOMEM)
-                       return WIMLIB_ERR_NOMEM;
-
-       if (!wim_info_get_wimboot(ctx->common.wim->wim_info,
-                                 ctx->common.wim->current_image))
+       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.");
@@ -637,7 +696,7 @@ start_wimboot_extraction(struct list_head *dentry_list, struct win32_apply_ctx *
        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
                struct blob_descriptor *blob;
 
-               ret = win32_will_externally_back(dentry, &ctx->common);
+               ret = win32_will_back_from_wim(dentry, &ctx->common);
                if (ret > 0) /* Error */
                        return ret;
                if (ret < 0) /* Won't externally back */
@@ -843,7 +902,9 @@ build_extraction_path(const struct wim_dentry *dentry,
             d = d->d_parent)
        {
                p -= d->d_extraction_name_nchars;
-               wmemcpy(p, d->d_extraction_name, 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  */
@@ -931,6 +992,9 @@ open_target_directory(struct win32_apply_ctx *ctx)
        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 = (*func_NtCreateFile)(&ctx->h_target,
                                      FILE_TRAVERSE,
                                      &ctx->attr,
@@ -940,7 +1004,6 @@ open_target_directory(struct win32_apply_ctx *ctx)
                                      FILE_SHARE_VALID_FLAGS,
                                      FILE_OPEN_IF,
                                      FILE_DIRECTORY_FILE |
-                                             FILE_OPEN_REPARSE_POINT |
                                              FILE_OPEN_FOR_BACKUP_INTENT,
                                      NULL,
                                      0);
@@ -1029,6 +1092,9 @@ adjust_compression_attribute(HANDLE h, const struct wim_dentry *dentry,
 {
        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;
@@ -1036,9 +1102,6 @@ adjust_compression_attribute(HANDLE h, const struct wim_dentry *dentry,
        if (!ctx->common.supported_features.compressed_files)
                return 0;
 
-       FILE_BASIC_INFORMATION info;
-       NTSTATUS status;
-       USHORT compression_state;
 
        /* Get current attributes  */
        status = (*func_NtQueryInformationFile)(h, &ctx->iosb,
@@ -1058,18 +1121,10 @@ adjust_compression_attribute(HANDLE h, const struct wim_dentry *dentry,
        else
                compression_state = COMPRESSION_FORMAT_NONE;
 
-       status = (*func_NtFsControlFile)(h,
-                                        NULL,
-                                        NULL,
-                                        NULL,
-                                        &ctx->iosb,
-                                        FSCTL_SET_COMPRESSION,
-                                        &compression_state,
-                                        sizeof(USHORT),
-                                        NULL,
-                                        0);
+       status = winnt_fsctl(h, FSCTL_SET_COMPRESSION,
+                            &compression_state, sizeof(USHORT), NULL, 0, NULL);
        if (NT_SUCCESS(status))
-               return 0;
+               return status;
 
        winnt_error(status, L"Can't %s compression attribute on \"%ls\"",
                    (compressed ? "set" : "clear"), current_path(ctx));
@@ -1289,7 +1344,7 @@ retry:
  * A wrapper around NtCreateFile() to make it slightly more usable...
  * This uses the path currently constructed in ctx->pathbuf.
  *
- * Also, we always specify FILE_OPEN_FOR_BACKUP_INTENT and
+ * Also, we always specify SYNCHRONIZE access, FILE_OPEN_FOR_BACKUP_INTENT, and
  * FILE_OPEN_REPARSE_POINT.
  */
 static NTSTATUS
@@ -1302,7 +1357,7 @@ do_create_file(PHANDLE FileHandle,
               struct win32_apply_ctx *ctx)
 {
        return (*func_NtCreateFile)(FileHandle,
-                                   DesiredAccess,
+                                   DesiredAccess | SYNCHRONIZE,
                                    &ctx->attr,
                                    &ctx->iosb,
                                    AllocationSize,
@@ -1343,67 +1398,71 @@ delete_file_or_stream(struct win32_apply_ctx *ctx)
 {
        NTSTATUS status;
        HANDLE h;
-       FILE_DISPOSITION_INFORMATION disposition_info;
-       FILE_BASIC_INFORMATION basic_info;
-       bool retried = false;
+       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;
+               }
+       }
 
-       status = do_create_file(&h,
-                               DELETE,
-                               NULL,
-                               0,
-                               FILE_OPEN,
-                               FILE_NON_DIRECTORY_FILE,
-                               ctx);
        if (unlikely(!NT_SUCCESS(status))) {
-               winnt_error(status, L"Can't open \"%ls\" for deletion",
-                           current_path(ctx));
+               winnt_error(status, L"Can't open \"%ls\" for deletion "
+                           "(perms=%x, flags=%x)",
+                           current_path(ctx), perms, flags);
                return WIMLIB_ERR_OPEN;
        }
 
-retry:
-       disposition_info.DoDeleteFile = TRUE;
-       status = (*func_NtSetInformationFile)(h, &ctx->iosb,
-                                             &disposition_info,
-                                             sizeof(disposition_info),
-                                             FileDispositionInformation);
-       (*func_NtClose)(h);
-       if (likely(NT_SUCCESS(status)))
-               return 0;
+       if (unlikely(!(flags & FILE_DELETE_ON_CLOSE))) {
 
-       if (status == STATUS_CANNOT_DELETE && !retried) {
-               /* Clear file attributes and try again.  This is necessary for
-                * FILE_ATTRIBUTE_READONLY files.  */
-               status = do_create_file(&h,
-                                       FILE_WRITE_ATTRIBUTES | DELETE,
-                                       NULL,
-                                       0,
-                                       FILE_OPEN,
-                                       FILE_NON_DIRECTORY_FILE,
-                                       ctx);
-               if (!NT_SUCCESS(status)) {
-                       winnt_error(status,
-                                   L"Can't open \"%ls\" to reset attributes",
-                                   current_path(ctx));
-                       return WIMLIB_ERR_OPEN;
-               }
-               memset(&basic_info, 0, sizeof(basic_info));
-               basic_info.FileAttributes = FILE_ATTRIBUTE_NORMAL;
+               FILE_BASIC_INFORMATION basic_info =
+                       { .FileAttributes = FILE_ATTRIBUTE_NORMAL };
                status = (*func_NtSetInformationFile)(h, &ctx->iosb,
                                                      &basic_info,
                                                      sizeof(basic_info),
                                                      FileBasicInformation);
+
                if (!NT_SUCCESS(status)) {
-                       winnt_error(status,
-                                   L"Can't reset file attributes on \"%ls\"",
-                                   current_path(ctx));
+                       winnt_error(status, L"Can't reset attributes of \"%ls\" "
+                                   "to prepare for deletion", current_path(ctx));
+                       (*func_NtClose)(h);
+                       return WIMLIB_ERR_SET_ATTRIBUTES;
+               }
+
+               FILE_DISPOSITION_INFORMATION disp_info =
+                       { .DoDeleteFile = TRUE };
+               status = (*func_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));
                        (*func_NtClose)(h);
                        return WIMLIB_ERR_SET_ATTRIBUTES;
                }
-               retried = true;
-               goto retry;
        }
-       winnt_error(status, L"Can't delete \"%ls\"", current_path(ctx));
-       return WIMLIB_ERR_OPEN;
+
+       status = (*func_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;
 }
 
 /*
@@ -1463,10 +1522,8 @@ do_set_reparse_point(const struct wim_dentry *dentry,
        if (!NT_SUCCESS(status))
                goto fail;
 
-       status = (*func_NtFsControlFile)(h, NULL, NULL, NULL,
-                                        &ctx->iosb, FSCTL_SET_REPARSE_POINT,
-                                        (void *)rpbuf, rpbuflen,
-                                        NULL, 0);
+       status = winnt_fsctl(h, FSCTL_SET_REPARSE_POINT,
+                            rpbuf, rpbuflen, NULL, 0, NULL);
        (*func_NtClose)(h);
 
        if (NT_SUCCESS(status))
@@ -1564,18 +1621,46 @@ create_directory(const struct wim_dentry *dentry, struct win32_apply_ctx *ctx)
        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;
+        * are needed for adjust_compression_attribute(); WRITE_DAC is needed to
+        * remove the directory's DACL if the directory already existed  */
+       perms = GENERIC_READ | GENERIC_WRITE | WRITE_DAC;
        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.  */
+retry:
        status = create_file(&h, perms, NULL, FILE_ATTRIBUTE_SYSTEM,
                             FILE_OPEN_IF, FILE_DIRECTORY_FILE, dentry, ctx);
-       if (!NT_SUCCESS(status)) {
-               winnt_error(status, L"Can't create directory \"%ls\"",
-                           current_path(ctx));
+       if (unlikely(!NT_SUCCESS(status))) {
+               if (status == STATUS_ACCESS_DENIED) {
+                       if (perms & WRITE_DAC) {
+                               perms &= ~WRITE_DAC;
+                               goto retry;
+                       }
+                       if (perms & DELETE) {
+                               perms &= ~DELETE;
+                               goto retry;
+                       }
+               }
+               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;
        }
 
@@ -1588,9 +1673,32 @@ create_directory(const struct wim_dentry *dentry, struct win32_apply_ctx *ctx)
                 * directory, even though this contradicts Microsoft's
                 * documentation for FILE_ATTRIBUTE_READONLY which states it is
                 * not honored for directories!  */
-               FILE_BASIC_INFORMATION basic_info = { .FileAttributes = FILE_ATTRIBUTE_NORMAL };
-               (*func_NtSetInformationFile)(h, &ctx->iosb, &basic_info,
-                                            sizeof(basic_info), FileBasicInformation);
+               if (!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ATTRIBUTES)) {
+                       FILE_BASIC_INFORMATION basic_info =
+                               { .FileAttributes = FILE_ATTRIBUTE_NORMAL };
+                       (*func_NtSetInformationFile)(h, &ctx->iosb, &basic_info,
+                                                    sizeof(basic_info),
+                                                    FileBasicInformation);
+               }
+
+               /* Also try to remove the directory's DACL.  This isn't supposed
+                * to be necessary because we *always* use backup semantics.
+                * However, there is a case where NtCreateFile() fails with
+                * STATUS_ACCESS_DENIED when creating a named data stream that
+                * was just deleted, using a directory-relative open.  I have no
+                * idea why Windows is broken in this case.  */
+               if (!(ctx->common.extract_flags & WIMLIB_EXTRACT_FLAG_NO_ACLS)) {
+                       static const SECURITY_DESCRIPTOR_RELATIVE desc = {
+                               .Revision = SECURITY_DESCRIPTOR_REVISION1,
+                               .Control = SE_SELF_RELATIVE | SE_DACL_PRESENT,
+                               .Owner = 0,
+                               .Group = 0,
+                               .Sacl = 0,
+                               .Dacl = 0,
+                       };
+                       (*func_NtSetSecurityObject)(h, DACL_SECURITY_INFORMATION,
+                                                   (void *)&desc);
+               }
        }
 
        if (!dentry_is_root(dentry)) {
@@ -1780,7 +1888,7 @@ create_nondirectory(struct wim_inode *inode, struct win32_apply_ctx *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_external_backing(h, inode, ctx);
+               ret = set_backed_from_wim(h, inode, ctx);
 
        (*func_NtClose)(h);
        return ret;
@@ -2012,6 +2120,26 @@ try_rpfix(struct reparse_buffer_disk *rpbuf, u16 *rpbuflen_p,
 
        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];
@@ -2210,6 +2338,259 @@ extract_chunk(const void *chunk, size_t size, void *_ctx)
        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 wchar_t *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_set bootloader_patterns = {
+       .strings = 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;
+               }
+       }
+
+       (*func_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 on Windows  */
 static int
 end_extract_blob(struct blob_descriptor *blob, int status, void *_ctx)
@@ -2223,6 +2604,9 @@ end_extract_blob(struct blob_descriptor *blob, int status, void *_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;
 
@@ -2622,6 +3006,9 @@ win32_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
                        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);
@@ -2676,11 +3063,11 @@ out:
        FREE(ctx->pathbuf.Buffer);
        FREE(ctx->print_buffer);
        FREE(ctx->wimboot.wims);
-       if (ctx->wimboot.prepopulate_pats) {
-               FREE(ctx->wimboot.prepopulate_pats->strings);
-               FREE(ctx->wimboot.prepopulate_pats);
+       if (ctx->prepopulate_pats) {
+               FREE(ctx->prepopulate_pats->strings);
+               FREE(ctx->prepopulate_pats);
        }
-       FREE(ctx->wimboot.mem_prepopulate_pats);
+       FREE(ctx->mem_prepopulate_pats);
        FREE(ctx->data_buffer);
        return ret;
 }
@@ -2689,7 +3076,7 @@ const struct apply_operations win32_apply_ops = {
        .name                   = "Windows",
        .get_supported_features = win32_get_supported_features,
        .extract                = win32_extract,
-       .will_externally_back   = win32_will_externally_back,
+       .will_back_from_wim     = win32_will_back_from_wim,
        .context_size           = sizeof(struct win32_apply_ctx),
 };