Add support for a data recovery mode

[wimlib] / src / win32_capture.c

/*
 * win32_capture.c - Windows-specific code for capturing files into a WIM image.
 *
 * This now uses the native Windows NT API a lot and not just Win32.
 */

/*
 * 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/assert.h"
#include "wimlib/blob_table.h"
#include "wimlib/dentry.h"
#include "wimlib/encoding.h"
#include "wimlib/endianness.h"
#include "wimlib/error.h"
#include "wimlib/object_id.h"
#include "wimlib/paths.h"
#include "wimlib/reparse.h"
#include "wimlib/scan.h"
#include "wimlib/win32_vss.h"
#include "wimlib/wof.h"
#include "wimlib/xattr.h"

struct winnt_scan_ctx {
        struct scan_params *params;
        bool is_ntfs;
        u32 vol_flags;
        unsigned long num_get_sd_access_denied;
        unsigned long num_get_sacl_priv_notheld;

        /* True if WOF is definitely not attached to the volume being scanned;
         * false if it may be  */
        bool wof_not_attached;

        /* A reference to the VSS snapshot being used, or NULL if none  */
        struct vss_snapshot *snapshot;
};

static inline const wchar_t *
printable_path(const struct winnt_scan_ctx *ctx)
{
        /* Skip over \\?\ or \??\  */
        return ctx->params->cur_path + 4;
}

/* Description of where data is located on a Windows filesystem  */
struct windows_file {

        /* Is the data the raw encrypted data of an EFS-encrypted file?  */
        u64 is_encrypted : 1;

        /* Is this file "open by file ID" rather than the regular "open by
         * path"?  "Open by file ID" uses resources more efficiently.  */
        u64 is_file_id : 1;

        /* The file's LCN (logical cluster number) for sorting, or 0 if unknown.
         */
        u64 sort_key : 62;

        /* Length of the path in bytes, excluding the null terminator if
         * present.  */
        size_t path_nbytes;

        /* A reference to the VSS snapshot containing the file, or NULL if none.
         */
        struct vss_snapshot *snapshot;

        /* The path to the file.  If 'is_encrypted=0' this is an NT namespace
         * path; if 'is_encrypted=1' this is a Win32 namespace path.  If
         * 'is_file_id=0', then the path is null-terminated.  If 'is_file_id=1'
         * (only allowed with 'is_encrypted=0') the path ends with a binary file
         * ID and may not be null-terminated.  */
        wchar_t path[0];
};

/* Allocate a structure to describe the location of a data stream by path.  */
static struct windows_file *
alloc_windows_file(const wchar_t *path, size_t path_nchars,
                   const wchar_t *stream_name, size_t stream_name_nchars,
                   struct vss_snapshot *snapshot, bool is_encrypted)
{
        size_t full_path_nbytes;
        struct windows_file *file;
        wchar_t *p;

        full_path_nbytes = path_nchars * sizeof(wchar_t);
        if (stream_name_nchars)
                full_path_nbytes += (1 + stream_name_nchars) * sizeof(wchar_t);

        file = MALLOC(sizeof(struct windows_file) + full_path_nbytes +
                      sizeof(wchar_t));
        if (!file)
                return NULL;

        file->is_encrypted = is_encrypted;
        file->is_file_id = 0;
        file->sort_key = 0;
        file->path_nbytes = full_path_nbytes;
        file->snapshot = vss_get_snapshot(snapshot);
        p = wmempcpy(file->path, path, path_nchars);
        if (stream_name_nchars) {
                /* Named data stream  */
                *p++ = L':';
                p = wmempcpy(p, stream_name, stream_name_nchars);
        }
        *p = L'\0';
        return file;
}

/* Allocate a structure to describe the location of a file by ID.  */
static struct windows_file *
alloc_windows_file_for_file_id(u64 file_id, const wchar_t *root_path,
                               size_t root_path_nchars,
                               struct vss_snapshot *snapshot)
{
        size_t full_path_nbytes;
        struct windows_file *file;
        wchar_t *p;

        full_path_nbytes = (root_path_nchars * sizeof(wchar_t)) +
                           sizeof(file_id);
        file = MALLOC(sizeof(struct windows_file) + full_path_nbytes +
                      sizeof(wchar_t));
        if (!file)
                return NULL;

        file->is_encrypted = 0;
        file->is_file_id = 1;
        file->sort_key = 0;
        file->path_nbytes = full_path_nbytes;
        file->snapshot = vss_get_snapshot(snapshot);
        p = wmempcpy(file->path, root_path, root_path_nchars);
        p = mempcpy(p, &file_id, sizeof(file_id));
        *p = L'\0';
        return file;
}

/* Add a stream, located on a Windows filesystem, to the specified WIM inode. */
static int
add_stream(struct wim_inode *inode, struct windows_file *windows_file,
           u64 stream_size, int stream_type, const utf16lechar *stream_name,
           struct list_head *unhashed_blobs)
{
        struct blob_descriptor *blob = NULL;
        struct wim_inode_stream *strm;
        int ret;

        if (!windows_file)
                goto err_nomem;

        /* If the stream is nonempty, create a blob descriptor for it.  */
        if (stream_size) {
                blob = new_blob_descriptor();
                if (!blob)
                        goto err_nomem;
                blob->windows_file = windows_file;
                blob->blob_location = BLOB_IN_WINDOWS_FILE;
                blob->file_inode = inode;
                blob->size = stream_size;
                windows_file = NULL;
        }

        strm = inode_add_stream(inode, stream_type, stream_name, blob);
        if (!strm)
                goto err_nomem;

        prepare_unhashed_blob(blob, inode, strm->stream_id, unhashed_blobs);
        ret = 0;
out:
        if (windows_file)
                free_windows_file(windows_file);
        return ret;

err_nomem:
        free_blob_descriptor(blob);
        ret = WIMLIB_ERR_NOMEM;
        goto out;
}

struct windows_file *
clone_windows_file(const struct windows_file *file)
{
        struct windows_file *new;

        new = memdup(file, sizeof(*file) + file->path_nbytes + sizeof(wchar_t));
        if (new)
                vss_get_snapshot(new->snapshot);
        return new;
}

void
free_windows_file(struct windows_file *file)
{
        vss_put_snapshot(file->snapshot);
        FREE(file);
}

int
cmp_windows_files(const struct windows_file *file1,
                  const struct windows_file *file2)
{
        /* Compare by starting LCN (logical cluster number)  */
        int v = cmp_u64(file1->sort_key, file2->sort_key);
        if (v)
                return v;

        /* Fall back to comparing files by path (arbitrary heuristic).  */
        v = memcmp(file1->path, file2->path,
                   min(file1->path_nbytes, file2->path_nbytes));
        if (v)
                return v;

        return cmp_u32(file1->path_nbytes, file2->path_nbytes);
}

const wchar_t *
get_windows_file_path(const struct windows_file *file)
{
        return file->path;
}

/*
 * Open the file named by the NT namespace path @path of length @path_nchars
 * characters.  If @cur_dir is not NULL then the path is given relative to
 * @cur_dir; otherwise the path is absolute.  @perms is the access mask of
 * permissions to request on the handle.  SYNCHRONIZE permision is always added.
 */
static NTSTATUS
winnt_openat(HANDLE cur_dir, const wchar_t *path, size_t path_nchars,
             ACCESS_MASK perms, HANDLE *h_ret)
{
        UNICODE_STRING name = {
                .Length = path_nchars * sizeof(wchar_t),
                .MaximumLength = path_nchars * sizeof(wchar_t),
                .Buffer = (wchar_t *)path,
        };
        OBJECT_ATTRIBUTES attr = {
                .Length = sizeof(attr),
                .RootDirectory = cur_dir,
                .ObjectName = &name,
        };
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;
        ULONG options = FILE_OPEN_REPARSE_POINT | FILE_OPEN_FOR_BACKUP_INTENT;

        perms |= SYNCHRONIZE;
        if (perms & (FILE_READ_DATA | FILE_LIST_DIRECTORY)) {
                options |= FILE_SYNCHRONOUS_IO_NONALERT;
                options |= FILE_SEQUENTIAL_ONLY;
        }
retry:
        status = NtOpenFile(h_ret, perms, &attr, &iosb,
                            FILE_SHARE_VALID_FLAGS, options);
        if (!NT_SUCCESS(status)) {
                /* Try requesting fewer permissions  */
                if (status == STATUS_ACCESS_DENIED ||
                    status == STATUS_PRIVILEGE_NOT_HELD) {
                        if (perms & ACCESS_SYSTEM_SECURITY) {
                                perms &= ~ACCESS_SYSTEM_SECURITY;
                                goto retry;
                        }
                        if (perms & READ_CONTROL) {
                                perms &= ~READ_CONTROL;
                                goto retry;
                        }
                }
        }
        return status;
}

static NTSTATUS
winnt_open(const wchar_t *path, size_t path_nchars, ACCESS_MASK perms,
           HANDLE *h_ret)
{
        return winnt_openat(NULL, path, path_nchars, perms, h_ret);
}

static const wchar_t *
windows_file_to_string(const struct windows_file *file, u8 *buf, size_t bufsize)
{
        if (file->is_file_id) {
                u64 file_id;
                memcpy(&file_id,
                       (u8 *)file->path + file->path_nbytes - sizeof(file_id),
                       sizeof(file_id));
                swprintf((wchar_t *)buf, L"NTFS inode 0x%016"PRIx64, file_id);
        } else if (file->path_nbytes + 3 * sizeof(wchar_t) <= bufsize) {
                swprintf((wchar_t *)buf, L"\"%ls\"", file->path);
        } else {
                return L"(name too long)";
        }
        return (wchar_t *)buf;
}

static int
read_winnt_stream_prefix(const struct windows_file *file,
                         u64 size, const struct consume_chunk_callback *cb)
{
        IO_STATUS_BLOCK iosb;
        UNICODE_STRING name = {
                .Buffer = (wchar_t *)file->path,
                .Length = file->path_nbytes,
                .MaximumLength = file->path_nbytes,
        };
        OBJECT_ATTRIBUTES attr = {
                .Length = sizeof(attr),
                .ObjectName = &name,
        };
        HANDLE h;
        NTSTATUS status;
        u8 buf[BUFFER_SIZE] _aligned_attribute(8);
        u64 bytes_remaining;
        int ret;

        status = NtOpenFile(&h, FILE_READ_DATA | SYNCHRONIZE,
                            &attr, &iosb,
                            FILE_SHARE_VALID_FLAGS,
                            FILE_OPEN_REPARSE_POINT |
                                FILE_OPEN_FOR_BACKUP_INTENT |
                                FILE_SYNCHRONOUS_IO_NONALERT |
                                FILE_SEQUENTIAL_ONLY |
                                (file->is_file_id ? FILE_OPEN_BY_FILE_ID : 0));
        if (unlikely(!NT_SUCCESS(status))) {
                if (status == STATUS_SHARING_VIOLATION) {
                        ERROR("Can't open %ls for reading:\n"
                              "        File is in use by another process! "
                              "Consider using snapshot (VSS) mode.",
                              windows_file_to_string(file, buf, sizeof(buf)));
                } else {
                        winnt_error(status, L"Can't open %ls for reading",
                                    windows_file_to_string(file, buf, sizeof(buf)));
                }
                return WIMLIB_ERR_OPEN;
        }

        ret = 0;
        bytes_remaining = size;
        while (bytes_remaining) {
                IO_STATUS_BLOCK iosb;
                ULONG count;
                ULONG bytes_read;
                const unsigned max_tries = 5;
                unsigned tries_remaining = max_tries;

                count = min(sizeof(buf), bytes_remaining);

        retry_read:
                status = NtReadFile(h, NULL, NULL, NULL,
                                    &iosb, buf, count, NULL, NULL);
                if (unlikely(!NT_SUCCESS(status))) {
                        if (status == STATUS_END_OF_FILE) {
                                ERROR("%ls: File was concurrently truncated",
                                      windows_file_to_string(file, buf, sizeof(buf)));
                                ret = WIMLIB_ERR_CONCURRENT_MODIFICATION_DETECTED;
                        } else {
                                winnt_warning(status, L"Error reading data from %ls",
                                              windows_file_to_string(file, buf, sizeof(buf)));

                                /* Currently these retries are purely a guess;
                                 * there is no reproducible problem that they solve.  */
                                if (--tries_remaining) {
                                        int delay = 100;
                                        if (status == STATUS_INSUFFICIENT_RESOURCES ||
                                            status == STATUS_NO_MEMORY) {
                                                delay *= 25;
                                        }
                                        WARNING("Retrying after %dms...", delay);
                                        Sleep(delay);
                                        goto retry_read;
                                }
                                ERROR("Too many retries; returning failure");
                                ret = WIMLIB_ERR_READ;
                        }
                        break;
                } else if (unlikely(tries_remaining != max_tries)) {
                        WARNING("A read request had to be retried multiple times "
                                "before it succeeded!");
                }

                bytes_read = iosb.Information;

                bytes_remaining -= bytes_read;
                ret = consume_chunk(cb, buf, bytes_read);
                if (ret)
                        break;
        }
        NtClose(h);
        return ret;
}

struct win32_encrypted_read_ctx {
        const struct consume_chunk_callback *cb;
        int wimlib_err_code;
        u64 bytes_remaining;
};

static DWORD WINAPI
win32_encrypted_export_cb(unsigned char *data, void *_ctx, unsigned long len)
{
        struct win32_encrypted_read_ctx *ctx = _ctx;
        int ret;
        size_t bytes_to_consume = min(len, ctx->bytes_remaining);

        if (bytes_to_consume == 0)
                return ERROR_SUCCESS;

        ret = consume_chunk(ctx->cb, data, bytes_to_consume);
        if (ret) {
                ctx->wimlib_err_code = ret;
                /* It doesn't matter what error code is returned here, as long
                 * as it isn't ERROR_SUCCESS.  */
                return ERROR_READ_FAULT;
        }
        ctx->bytes_remaining -= bytes_to_consume;
        return ERROR_SUCCESS;
}

static int
read_win32_encrypted_file_prefix(const wchar_t *path, bool is_dir, u64 size,
                                 const struct consume_chunk_callback *cb)
{
        struct win32_encrypted_read_ctx export_ctx;
        DWORD err;
        void *file_ctx;
        int ret;
        DWORD flags = 0;

        if (is_dir)
                flags |= CREATE_FOR_DIR;

        export_ctx.cb = cb;
        export_ctx.wimlib_err_code = 0;
        export_ctx.bytes_remaining = size;

        err = OpenEncryptedFileRaw(path, flags, &file_ctx);
        if (err != ERROR_SUCCESS) {
                win32_error(err,
                            L"Failed to open encrypted file \"%ls\" for raw read",
                            path);
                return WIMLIB_ERR_OPEN;
        }
        err = ReadEncryptedFileRaw(win32_encrypted_export_cb,
                                   &export_ctx, file_ctx);
        if (err != ERROR_SUCCESS) {
                ret = export_ctx.wimlib_err_code;
                if (ret == 0) {
                        win32_error(err,
                                    L"Failed to read encrypted file \"%ls\"",
                                    path);
                        ret = WIMLIB_ERR_READ;
                }
        } else if (export_ctx.bytes_remaining != 0) {
                ERROR("Only could read %"PRIu64" of %"PRIu64" bytes from "
                      "encrypted file \"%ls\"",
                      size - export_ctx.bytes_remaining, size,
                      path);
                ret = WIMLIB_ERR_READ;
        } else {
                ret = 0;
        }
        CloseEncryptedFileRaw(file_ctx);
        return ret;
}

/* Read the first @size bytes from the file, or named data stream of a file,
 * described by @blob.  */
int
read_windows_file_prefix(const struct blob_descriptor *blob, u64 size,
                         const struct consume_chunk_callback *cb,
                         bool recover_data)
{
        const struct windows_file *file = blob->windows_file;

        if (unlikely(file->is_encrypted)) {
                bool is_dir = (blob->file_inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY);
                return read_win32_encrypted_file_prefix(file->path, is_dir, size, cb);
        }

        return read_winnt_stream_prefix(file, size, cb);
}

/*
 * Load the short name of a file into a WIM dentry.
 */
static noinline_for_stack NTSTATUS
winnt_get_short_name(HANDLE h, struct wim_dentry *dentry)
{
        /* It's not any harder to just make the NtQueryInformationFile() system
         * call ourselves, and it saves a dumb call to FindFirstFile() which of
         * course has to create its own handle.  */
        NTSTATUS status;
        IO_STATUS_BLOCK iosb;
        u8 buf[128] _aligned_attribute(8);
        const FILE_NAME_INFORMATION *info;

        status = NtQueryInformationFile(h, &iosb, buf, sizeof(buf),
                                        FileAlternateNameInformation);
        info = (const FILE_NAME_INFORMATION *)buf;
        if (NT_SUCCESS(status) && info->FileNameLength != 0) {
                dentry->d_short_name = utf16le_dupz(info->FileName,
                                                    info->FileNameLength);
                if (!dentry->d_short_name)
                        return STATUS_NO_MEMORY;
                dentry->d_short_name_nbytes = info->FileNameLength;
        }
        return status;
}

/*
 * Load the security descriptor of a file into the corresponding inode and the
 * WIM image's security descriptor set.
 */
static noinline_for_stack int
winnt_load_security_descriptor(HANDLE h, struct wim_inode *inode,
                               struct winnt_scan_ctx *ctx)
{
        SECURITY_INFORMATION requestedInformation;
        u8 _buf[4096] _aligned_attribute(8);
        u8 *buf;
        ULONG bufsize;
        ULONG len_needed;
        NTSTATUS status;

        /*
         * LABEL_SECURITY_INFORMATION is needed on Windows Vista and 7 because
         * Microsoft decided to add mandatory integrity labels to the SACL but
         * not have them returned by SACL_SECURITY_INFORMATION.
         *
         * BACKUP_SECURITY_INFORMATION is needed on Windows 8 because Microsoft
         * decided to add even more stuff to the SACL and still not have it
         * returned by SACL_SECURITY_INFORMATION; but they did remember that
         * backup applications exist and simply want to read the stupid thing
         * once and for all, so they added a flag to read the entire security
         * descriptor.
         *
         * Older versions of Windows tolerate these new flags being passed in.
         */
        requestedInformation = OWNER_SECURITY_INFORMATION |
                               GROUP_SECURITY_INFORMATION |
                               DACL_SECURITY_INFORMATION |
                               SACL_SECURITY_INFORMATION |
                               LABEL_SECURITY_INFORMATION |
                               BACKUP_SECURITY_INFORMATION;

        buf = _buf;
        bufsize = sizeof(_buf);

        /*
         * We need the file's security descriptor in
         * SECURITY_DESCRIPTOR_RELATIVE format, and we currently have a handle
         * opened with as many relevant permissions as possible.  At this point,
         * on Windows there are a number of options for reading a file's
         * security descriptor:
         *
         * GetFileSecurity():  This takes in a path and returns the
         * SECURITY_DESCRIPTOR_RELATIVE.  Problem: this uses an internal handle,
         * not ours, and the handle created internally doesn't specify
         * FILE_FLAG_BACKUP_SEMANTICS.  Therefore there can be access denied
         * errors on some files and directories, even when running as the
         * Administrator.
         *
         * GetSecurityInfo():  This takes in a handle and returns the security
         * descriptor split into a bunch of different parts.  This should work,
         * but it's dumb because we have to put the security descriptor back
         * together again.
         *
         * BackupRead():  This can read the security descriptor, but this is a
         * difficult-to-use API, probably only works as the Administrator, and
         * the format of the returned data is not well documented.
         *
         * NtQuerySecurityObject():  This is exactly what we need, as it takes
         * in a handle and returns the security descriptor in
         * SECURITY_DESCRIPTOR_RELATIVE format.  Only problem is that it's a
         * ntdll function and therefore not officially part of the Win32 API.
         * Oh well.
         */
        while (!NT_SUCCESS(status = NtQuerySecurityObject(h,
                                                          requestedInformation,
                                                          (PSECURITY_DESCRIPTOR)buf,
                                                          bufsize,
                                                          &len_needed)))
        {
                switch (status) {
                case STATUS_BUFFER_TOO_SMALL:
                        wimlib_assert(buf == _buf);
                        buf = MALLOC(len_needed);
                        if (!buf) {
                                status = STATUS_NO_MEMORY;
                                goto out;
                        }
                        bufsize = len_needed;
                        break;
                case STATUS_PRIVILEGE_NOT_HELD:
                case STATUS_ACCESS_DENIED:
                        if (ctx->params->add_flags & WIMLIB_ADD_FLAG_STRICT_ACLS) {
                default:
                                /* Permission denied in STRICT_ACLS mode, or
                                 * unknown error.  */
                                goto out;
                        }
                        if (requestedInformation & SACL_SECURITY_INFORMATION) {
                                /* Try again without the SACL.  */
                                ctx->num_get_sacl_priv_notheld++;
                                requestedInformation &= ~(SACL_SECURITY_INFORMATION |
                                                          LABEL_SECURITY_INFORMATION |
                                                          BACKUP_SECURITY_INFORMATION);
                                break;
                        }
                        /* Fake success (useful when capturing as
                         * non-Administrator).  */
                        ctx->num_get_sd_access_denied++;
                        status = STATUS_SUCCESS;
                        goto out;
                }
        }

        /* We can get a length of 0 with Samba.  Assume that means "no security
         * descriptor".  */
        if (len_needed == 0)
                goto out;

        /* Add the security descriptor to the WIM image, and save its ID in
         * the file's inode.  */
        inode->i_security_id = sd_set_add_sd(ctx->params->sd_set, buf, len_needed);
        if (unlikely(inode->i_security_id < 0))
                status = STATUS_NO_MEMORY;
out:
        if (unlikely(buf != _buf))
                FREE(buf);
        if (!NT_SUCCESS(status)) {
                winnt_error(status, L"\"%ls\": Can't read security descriptor",
                            printable_path(ctx));
                return WIMLIB_ERR_STAT;
        }
        return 0;
}

/* Load a file's object ID into the corresponding WIM inode.  */
static noinline_for_stack int
winnt_load_object_id(HANDLE h, struct wim_inode *inode,
                     struct winnt_scan_ctx *ctx)
{
        FILE_OBJECTID_BUFFER buffer;
        NTSTATUS status;
        u32 len;

        if (!(ctx->vol_flags & FILE_SUPPORTS_OBJECT_IDS))
                return 0;

        status = winnt_fsctl(h, FSCTL_GET_OBJECT_ID, NULL, 0,
                             &buffer, sizeof(buffer), &len);

        if (status == STATUS_OBJECTID_NOT_FOUND) /* No object ID  */
                return 0;

        if (status == STATUS_INVALID_DEVICE_REQUEST ||
            status == STATUS_NOT_SUPPORTED /* Samba volume, WinXP */) {
                /* The filesystem claimed to support object IDs, but we can't
                 * actually read them.  This happens with Samba.  */
                ctx->vol_flags &= ~FILE_SUPPORTS_OBJECT_IDS;
                return 0;
        }

        if (!NT_SUCCESS(status)) {
                winnt_error(status, L"\"%ls\": Can't read object ID",
                            printable_path(ctx));
                return WIMLIB_ERR_STAT;
        }

        if (len == 0) /* No object ID (for directories)  */
                return 0;

        if (!inode_set_object_id(inode, &buffer, len))
                return WIMLIB_ERR_NOMEM;

        return 0;
}

/* Load a file's extended attributes into the corresponding WIM inode.  */
static noinline_for_stack int
winnt_load_xattrs(HANDLE h, struct wim_inode *inode,
                  struct winnt_scan_ctx *ctx, u32 ea_size)
{
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;
        u8 _buf[1024] _aligned_attribute(4);
        u8 *buf = _buf;
        const FILE_FULL_EA_INFORMATION *ea;
        struct wim_xattr_entry *entry;
        int ret;


        /*
         * EaSize from FILE_EA_INFORMATION is apparently supposed to give the
         * size of the buffer required for NtQueryEaFile(), but it doesn't
         * actually work correctly; it can be off by about 4 bytes per xattr.
         *
         * So just start out by doubling the advertised size, and also handle
         * STATUS_BUFFER_OVERFLOW just in case.
         */
retry:
        if (unlikely(ea_size * 2 < ea_size))
                ea_size = UINT32_MAX;
        else
                ea_size *= 2;
        if (unlikely(ea_size > sizeof(_buf))) {
                buf = MALLOC(ea_size);
                if (!buf) {
                        if (ea_size >= (1 << 20)) {
                                WARNING("\"%ls\": EaSize was extremely large (%u)",
                                        printable_path(ctx), ea_size);
                        }
                        return WIMLIB_ERR_NOMEM;
                }
        }

        status = NtQueryEaFile(h, &iosb, buf, ea_size,
                               FALSE, NULL, 0, NULL, TRUE);

        if (unlikely(!NT_SUCCESS(status))) {
                if (status == STATUS_BUFFER_OVERFLOW) {
                        if (buf != _buf) {
                                FREE(buf);
                                buf = NULL;
                        }
                        goto retry;
                }
                if (status == STATUS_NO_EAS_ON_FILE) {
                        /*
                         * FILE_EA_INFORMATION.EaSize was nonzero so this
                         * shouldn't happen, but just in case...
                         */
                        ret = 0;
                        goto out;
                }
                winnt_error(status, L"\"%ls\": Can't read extended attributes",
                            printable_path(ctx));
                ret = WIMLIB_ERR_STAT;
                goto out;
        }

        ea = (const FILE_FULL_EA_INFORMATION *)buf;
        entry = (struct wim_xattr_entry *)buf;
        for (;;) {
                /*
                 * wim_xattr_entry is not larger than FILE_FULL_EA_INFORMATION,
                 * so we can reuse the same buffer by overwriting the
                 * FILE_FULL_EA_INFORMATION with the wim_xattr_entry in-place.
                 */
                FILE_FULL_EA_INFORMATION _ea;

                STATIC_ASSERT(offsetof(struct wim_xattr_entry, name) <=
                              offsetof(FILE_FULL_EA_INFORMATION, EaName));
                wimlib_assert((u8 *)entry <= (const u8 *)ea);

                memcpy(&_ea, ea, sizeof(_ea));

                entry->value_len = cpu_to_le16(_ea.EaValueLength);
                entry->name_len = _ea.EaNameLength;
                entry->flags = _ea.Flags;
                memmove(entry->name, ea->EaName, _ea.EaNameLength);
                entry->name[_ea.EaNameLength] = '\0';
                memmove(&entry->name[_ea.EaNameLength + 1],
                        &ea->EaName[_ea.EaNameLength + 1], _ea.EaValueLength);
                entry = (struct wim_xattr_entry *)
                         &entry->name[_ea.EaNameLength + 1 + _ea.EaValueLength];
                if (_ea.NextEntryOffset == 0)
                        break;
                ea = (const FILE_FULL_EA_INFORMATION *)
                        ((const u8 *)ea + _ea.NextEntryOffset);
        }
        wimlib_assert((u8 *)entry - buf <= ea_size);

        ret = WIMLIB_ERR_NOMEM;
        if (!inode_set_xattrs(inode, buf, (u8 *)entry - buf))
                goto out;
        ret = 0;
out:
        if (unlikely(buf != _buf))
                FREE(buf);
        return ret;
}

static int
winnt_build_dentry_tree(struct wim_dentry **root_ret,
                        HANDLE cur_dir,
                        const wchar_t *relative_path,
                        size_t relative_path_nchars,
                        const wchar_t *filename,
                        struct winnt_scan_ctx *ctx,
                        bool recursive);

static int
winnt_recurse_directory(HANDLE h,
                        struct wim_dentry *parent,
                        struct winnt_scan_ctx *ctx)
{
        void *buf;
        const size_t bufsize = 8192;
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;
        int ret;

        buf = MALLOC(bufsize);
        if (!buf)
                return WIMLIB_ERR_NOMEM;

        /* Using NtQueryDirectoryFile() we can re-use the same open handle,
         * which we opened with FILE_FLAG_BACKUP_SEMANTICS.  */

        while (NT_SUCCESS(status = NtQueryDirectoryFile(h, NULL, NULL, NULL,
                                                        &iosb, buf, bufsize,
                                                        FileNamesInformation,
                                                        FALSE, NULL, FALSE)))
        {
                const FILE_NAMES_INFORMATION *info = buf;
                for (;;) {
                        if (!should_ignore_filename(info->FileName,
                                                    info->FileNameLength / 2))
                        {
                                struct wim_dentry *child;
                                size_t orig_path_nchars;
                                const wchar_t *filename;

                                ret = WIMLIB_ERR_NOMEM;
                                filename = pathbuf_append_name(ctx->params,
                                                               info->FileName,
                                                               info->FileNameLength / 2,
                                                               &orig_path_nchars);
                                if (!filename)
                                        goto out_free_buf;

                                ret = winnt_build_dentry_tree(
                                                        &child,
                                                        h,
                                                        filename,
                                                        info->FileNameLength / 2,
                                                        filename,
                                                        ctx,
                                                        true);

                                pathbuf_truncate(ctx->params, orig_path_nchars);

                                if (ret)
                                        goto out_free_buf;
                                attach_scanned_tree(parent, child,
                                                    ctx->params->blob_table);
                        }
                        if (info->NextEntryOffset == 0)
                                break;
                        info = (const FILE_NAMES_INFORMATION *)
                                        ((const u8 *)info + info->NextEntryOffset);
                }
        }

        if (unlikely(status != STATUS_NO_MORE_FILES)) {
                winnt_error(status, L"\"%ls\": Can't read directory",
                            printable_path(ctx));
                ret = WIMLIB_ERR_READ;
        }
out_free_buf:
        FREE(buf);
        return ret;
}

/* Reparse point fixup status code  */
#define RP_FIXED        (-1)

static bool
file_has_ino_and_dev(HANDLE h, u64 ino, u64 dev)
{
        NTSTATUS status;
        IO_STATUS_BLOCK iosb;
        FILE_INTERNAL_INFORMATION int_info;
        FILE_FS_VOLUME_INFORMATION vol_info;

        status = NtQueryInformationFile(h, &iosb, &int_info, sizeof(int_info),
                                        FileInternalInformation);
        if (!NT_SUCCESS(status))
                return false;

        if (int_info.IndexNumber.QuadPart != ino)
                return false;

        status = NtQueryVolumeInformationFile(h, &iosb,
                                              &vol_info, sizeof(vol_info),
                                              FileFsVolumeInformation);
        if (!(NT_SUCCESS(status) || status == STATUS_BUFFER_OVERFLOW))
                return false;

        if (iosb.Information <
             offsetof(FILE_FS_VOLUME_INFORMATION, VolumeSerialNumber) +
             sizeof(vol_info.VolumeSerialNumber))
                return false;

        return (vol_info.VolumeSerialNumber == dev);
}

/*
 * This is the Windows equivalent of unix_relativize_link_target(); see there
 * for general details.  This version works with an "absolute" Windows link
 * target, specified from the root of the Windows kernel object namespace.  Note
 * that we have to open directories with a trailing slash when present because
 * \??\E: opens the E: device itself and not the filesystem root directory.
 */
static const wchar_t *
winnt_relativize_link_target(const wchar_t *target, size_t target_nbytes,
                             u64 ino, u64 dev)
{
        UNICODE_STRING name;
        OBJECT_ATTRIBUTES attr;
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;
        const wchar_t *target_end;
        const wchar_t *p;

        target_end = target + (target_nbytes / sizeof(wchar_t));

        /* Empty path??? */
        if (target_end == target)
                return target;

        /* No leading slash???  */
        if (target[0] != L'\\')
                return target;

        /* UNC path???  */
        if ((target_end - target) >= 2 &&
            target[0] == L'\\' && target[1] == L'\\')
                return target;

        attr.Length = sizeof(attr);
        attr.RootDirectory = NULL;
        attr.ObjectName = &name;
        attr.Attributes = 0;
        attr.SecurityDescriptor = NULL;
        attr.SecurityQualityOfService = NULL;

        name.Buffer = (wchar_t *)target;
        name.Length = 0;
        p = target;
        do {
                HANDLE h;
                const wchar_t *orig_p = p;

                /* Skip non-backslashes  */
                while (p != target_end && *p != L'\\')
                        p++;

                /* Skip backslashes  */
                while (p != target_end && *p == L'\\')
                        p++;

                /* Append path component  */
                name.Length += (p - orig_p) * sizeof(wchar_t);
                name.MaximumLength = name.Length;

                /* Try opening the file  */
                status = NtOpenFile(&h,
                                    FILE_READ_ATTRIBUTES | FILE_TRAVERSE,
                                    &attr,
                                    &iosb,
                                    FILE_SHARE_VALID_FLAGS,
                                    FILE_OPEN_FOR_BACKUP_INTENT);

                if (NT_SUCCESS(status)) {
                        /* Reset root directory  */
                        if (attr.RootDirectory)
                                NtClose(attr.RootDirectory);
                        attr.RootDirectory = h;
                        name.Buffer = (wchar_t *)p;
                        name.Length = 0;

                        if (file_has_ino_and_dev(h, ino, dev))
                                goto out_close_root_dir;
                }
        } while (p != target_end);

        p = target;

out_close_root_dir:
        if (attr.RootDirectory)
                NtClose(attr.RootDirectory);
        while (p > target && *(p - 1) == L'\\')
                p--;
        return p;
}

static int
winnt_rpfix_progress(struct scan_params *params,
                     const struct link_reparse_point *link, int scan_status)
{
        size_t print_name_nchars = link->print_name_nbytes / sizeof(wchar_t);
        wchar_t print_name0[print_name_nchars + 1];

        wmemcpy(print_name0, link->print_name, print_name_nchars);
        print_name0[print_name_nchars] = L'\0';

        params->progress.scan.symlink_target = print_name0;
        return do_scan_progress(params, scan_status, NULL);
}

static int
winnt_try_rpfix(struct reparse_buffer_disk *rpbuf, u16 *rpbuflen_p,
                struct scan_params *params)
{
        struct link_reparse_point link;
        const wchar_t *rel_target;
        int ret;

        if (parse_link_reparse_point(rpbuf, *rpbuflen_p, &link)) {
                /* Couldn't understand the reparse data; don't do the fixup.  */
                return 0;
        }

        /*
         * Don't do reparse point fixups on relative symbolic links.
         *
         * On Windows, a relative symbolic link is supposed to be identifiable
         * by having reparse tag WIM_IO_REPARSE_TAG_SYMLINK and flags
         * SYMBOLIC_LINK_RELATIVE.  We will use this information, although this
         * may not always do what the user expects, since drive-relative
         * symbolic links such as "\Users\Public" have SYMBOLIC_LINK_RELATIVE
         * set, in addition to truly relative symbolic links such as "Users" or
         * "Users\Public".  However, WIMGAPI (as of Windows 8.1) has this same
         * behavior.
         *
         * Otherwise, as far as I can tell, the targets of symbolic links that
         * are NOT relative, as well as junctions (note: a mountpoint is the
         * sames thing as a junction), must be NT namespace paths, for example:
         *
         *     - \??\e:\Users\Public
         *     - \DosDevices\e:\Users\Public
         *     - \Device\HardDiskVolume4\Users\Public
         *     - \??\Volume{c47cb07c-946e-4155-b8f7-052e9cec7628}\Users\Public
         *     - \DosDevices\Volume{c47cb07c-946e-4155-b8f7-052e9cec7628}\Users\Public
         */
        if (link_is_relative_symlink(&link))
                return 0;

        rel_target = winnt_relativize_link_target(link.substitute_name,
                                                  link.substitute_name_nbytes,
                                                  params->capture_root_ino,
                                                  params->capture_root_dev);

        if (rel_target == link.substitute_name) {
                /* Target points outside of the tree being captured or had an
                 * unrecognized path format.  Don't adjust it.  */
                return winnt_rpfix_progress(params, &link,
                                            WIMLIB_SCAN_DENTRY_NOT_FIXED_SYMLINK);
        }

        /* We have an absolute target pointing within the directory being
         * captured. @rel_target is the suffix of the link target that is the
         * part relative to the directory being captured.
         *
         * We will cut off the prefix before this part (which is the path to the
         * directory being captured) and add a dummy prefix.  Since the process
         * will need to be reversed when applying the image, it doesn't matter
         * what exactly the prefix is, as long as it looks like an absolute
         * path.  */

        static const wchar_t prefix[6] = L"\\??\\X:";
        static const size_t num_unprintable_chars = 4;

        size_t rel_target_nbytes =
                link.substitute_name_nbytes - ((const u8 *)rel_target -
                                               (const u8 *)link.substitute_name);

        wchar_t tmp[(sizeof(prefix) + rel_target_nbytes) / sizeof(wchar_t)];

        memcpy(tmp, prefix, sizeof(prefix));
        memcpy(tmp + ARRAY_LEN(prefix), rel_target, rel_target_nbytes);

        link.substitute_name = tmp;
        link.substitute_name_nbytes = sizeof(tmp);

        link.print_name = link.substitute_name + num_unprintable_chars;
        link.print_name_nbytes = link.substitute_name_nbytes -
                                 (num_unprintable_chars * sizeof(wchar_t));

        if (make_link_reparse_point(&link, rpbuf, rpbuflen_p))
                return 0;

        ret = winnt_rpfix_progress(params, &link,
                                   WIMLIB_SCAN_DENTRY_FIXED_SYMLINK);
        if (ret)
                return ret;
        return RP_FIXED;
}

/* Load the reparse data of a file into the corresponding WIM inode.  If the
 * reparse point is a symbolic link or junction with an absolute target and
 * RPFIX mode is enabled, then also rewrite its target to be relative to the
 * capture root.  */
static noinline_for_stack int
winnt_load_reparse_data(HANDLE h, struct wim_inode *inode,
                        struct winnt_scan_ctx *ctx)
{
        struct reparse_buffer_disk rpbuf;
        NTSTATUS status;
        u32 len;
        u16 rpbuflen;
        int ret;

        if (inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED) {
                /* See comment above assign_stream_types_encrypted()  */
                WARNING("Ignoring reparse data of encrypted file \"%ls\"",
                        printable_path(ctx));
                return 0;
        }

        status = winnt_fsctl(h, FSCTL_GET_REPARSE_POINT,
                             NULL, 0, &rpbuf, sizeof(rpbuf), &len);
        if (!NT_SUCCESS(status)) {
                winnt_error(status, L"\"%ls\": Can't get reparse point",
                            printable_path(ctx));
                return WIMLIB_ERR_READLINK;
        }

        rpbuflen = len;

        if (unlikely(rpbuflen < REPARSE_DATA_OFFSET)) {
                ERROR("\"%ls\": reparse point buffer is too short",
                      printable_path(ctx));
                return WIMLIB_ERR_INVALID_REPARSE_DATA;
        }

        if (le32_to_cpu(rpbuf.rptag) == WIM_IO_REPARSE_TAG_DEDUP) {
                /*
                 * Windows treats Data Deduplication reparse points specially.
                 * Reads from the unnamed data stream actually return the
                 * redirected file contents, even with FILE_OPEN_REPARSE_POINT.
                 * Deduplicated files also cannot be properly restored without
                 * also restoring the "System Volume Information" directory,
                 * which wimlib excludes by default.  Therefore, the logical
                 * behavior for us seems to be to ignore the reparse point and
                 * treat the file as a normal file.
                 */
                inode->i_attributes &= ~FILE_ATTRIBUTE_REPARSE_POINT;
                return 0;
        }

        if (ctx->params->add_flags & WIMLIB_ADD_FLAG_RPFIX) {
                ret = winnt_try_rpfix(&rpbuf, &rpbuflen, ctx->params);
                if (ret == RP_FIXED)
                        inode->i_rp_flags &= ~WIM_RP_FLAG_NOT_FIXED;
                else if (ret)
                        return ret;
        }

        inode->i_reparse_tag = le32_to_cpu(rpbuf.rptag);
        inode->i_rp_reserved = le16_to_cpu(rpbuf.rpreserved);

        if (!inode_add_stream_with_data(inode,
                                        STREAM_TYPE_REPARSE_POINT,
                                        NO_STREAM_NAME,
                                        rpbuf.rpdata,
                                        rpbuflen - REPARSE_DATA_OFFSET,
                                        ctx->params->blob_table))
                return WIMLIB_ERR_NOMEM;

        return 0;
}

static DWORD WINAPI
win32_tally_encrypted_size_cb(unsigned char *_data, void *_size_ret,
                              unsigned long len)
{
        *(u64*)_size_ret += len;
        return ERROR_SUCCESS;
}

static int
win32_get_encrypted_file_size(const wchar_t *path, bool is_dir, u64 *size_ret)
{
        DWORD err;
        void *file_ctx;
        int ret;
        DWORD flags = 0;

        if (is_dir)
                flags |= CREATE_FOR_DIR;

        err = OpenEncryptedFileRaw(path, flags, &file_ctx);
        if (err != ERROR_SUCCESS) {
                win32_error(err,
                            L"Failed to open encrypted file \"%ls\" for raw read",
                            path);
                return WIMLIB_ERR_OPEN;
        }
        *size_ret = 0;
        err = ReadEncryptedFileRaw(win32_tally_encrypted_size_cb,
                                   size_ret, file_ctx);
        if (err != ERROR_SUCCESS) {
                win32_error(err,
                            L"Failed to read raw encrypted data from \"%ls\"",
                            path);
                ret = WIMLIB_ERR_READ;
        } else {
                ret = 0;
        }
        CloseEncryptedFileRaw(file_ctx);
        return ret;
}

static int
winnt_scan_efsrpc_raw_data(struct wim_inode *inode,
                           struct winnt_scan_ctx *ctx)
{
        wchar_t *path = ctx->params->cur_path;
        size_t path_nchars = ctx->params->cur_path_nchars;
        const bool is_dir = (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY);
        struct windows_file *windows_file;
        u64 size;
        int ret;

        /* OpenEncryptedFileRaw() expects a Win32 name.  */
        wimlib_assert(!wmemcmp(path, L"\\??\\", 4));
        path[1] = L'\\';

        ret = win32_get_encrypted_file_size(path, is_dir, &size);
        if (ret)
                goto out;

        /* Empty EFSRPC data does not make sense  */
        wimlib_assert(size != 0);

        windows_file = alloc_windows_file(path, path_nchars, NULL, 0,
                                          ctx->snapshot, true);
        ret = add_stream(inode, windows_file, size, STREAM_TYPE_EFSRPC_RAW_DATA,
                         NO_STREAM_NAME, ctx->params->unhashed_blobs);
out:
        path[1] = L'?';
        return ret;
}

static bool
get_data_stream_name(const wchar_t *raw_stream_name, size_t raw_stream_name_nchars,
                     const wchar_t **stream_name_ret, size_t *stream_name_nchars_ret)
{
        const wchar_t *sep, *type, *end;

        /* The stream name should be returned as :NAME:TYPE  */
        if (raw_stream_name_nchars < 1)
                return false;
        if (raw_stream_name[0] != L':')
                return false;

        raw_stream_name++;
        raw_stream_name_nchars--;

        end = raw_stream_name + raw_stream_name_nchars;

        sep = wmemchr(raw_stream_name, L':', raw_stream_name_nchars);
        if (!sep)
                return false;

        type = sep + 1;
        if (end - type != 5)
                return false;

        if (wmemcmp(type, L"$DATA", 5))
                return false;

        *stream_name_ret = raw_stream_name;
        *stream_name_nchars_ret = sep - raw_stream_name;
        return true;
}

static int
winnt_scan_data_stream(wchar_t *raw_stream_name, size_t raw_stream_name_nchars,
                       u64 stream_size, struct wim_inode *inode,
                       struct winnt_scan_ctx *ctx)
{
        wchar_t *stream_name;
        size_t stream_name_nchars;
        struct windows_file *windows_file;

        /* Given the raw stream name (which is something like
         * :streamname:$DATA), extract just the stream name part (streamname).
         * Ignore any non-$DATA streams.  */
        if (!get_data_stream_name(raw_stream_name, raw_stream_name_nchars,
                                  (const wchar_t **)&stream_name,
                                  &stream_name_nchars))
                return 0;

        stream_name[stream_name_nchars] = L'\0';

        windows_file = alloc_windows_file(ctx->params->cur_path,
                                          ctx->params->cur_path_nchars,
                                          stream_name, stream_name_nchars,
                                          ctx->snapshot, false);
        return add_stream(inode, windows_file, stream_size, STREAM_TYPE_DATA,
                          stream_name, ctx->params->unhashed_blobs);
}

/*
 * Load information about the data streams of an open file into a WIM inode.
 *
 * We use the NtQueryInformationFile() system call instead of FindFirstStream()
 * and FindNextStream().  This is done for two reasons:
 *
 * - FindFirstStream() opens its own handle to the file or directory and
 *   apparently does so without specifying FILE_FLAG_BACKUP_SEMANTICS, thereby
 *   causing access denied errors on certain files (even when running as the
 *   Administrator).
 * - FindFirstStream() and FindNextStream() is only available on Windows Vista
 *   and later, whereas the stream support in NtQueryInformationFile() was
 *   already present in Windows XP.
 */
static noinline_for_stack int
winnt_scan_data_streams(HANDLE h, struct wim_inode *inode, u64 file_size,
                        struct winnt_scan_ctx *ctx)
{
        int ret;
        u8 _buf[4096] _aligned_attribute(8);
        u8 *buf;
        size_t bufsize;
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;
        FILE_STREAM_INFORMATION *info;

        buf = _buf;
        bufsize = sizeof(_buf);

        if (!(ctx->vol_flags & FILE_NAMED_STREAMS))
                goto unnamed_only;

        /* Get a buffer containing the stream information.  */
        while (!NT_SUCCESS(status = NtQueryInformationFile(h,
                                                           &iosb,
                                                           buf,
                                                           bufsize,
                                                           FileStreamInformation)))
        {

                switch (status) {
                case STATUS_BUFFER_OVERFLOW:
                        {
                                u8 *newbuf;

                                bufsize *= 2;
                                if (buf == _buf)
                                        newbuf = MALLOC(bufsize);
                                else
                                        newbuf = REALLOC(buf, bufsize);
                                if (!newbuf) {
                                        ret = WIMLIB_ERR_NOMEM;
                                        goto out_free_buf;
                                }
                                buf = newbuf;
                        }
                        break;
                case STATUS_NOT_IMPLEMENTED:
                case STATUS_NOT_SUPPORTED:
                case STATUS_INVALID_INFO_CLASS:
                        goto unnamed_only;
                default:
                        winnt_error(status,
                                    L"\"%ls\": Failed to query stream information",
                                    printable_path(ctx));
                        ret = WIMLIB_ERR_READ;
                        goto out_free_buf;
                }
        }

        if (iosb.Information == 0) {
                /* No stream information.  */
                ret = 0;
                goto out_free_buf;
        }

        /* Parse one or more stream information structures.  */
        info = (FILE_STREAM_INFORMATION *)buf;
        for (;;) {
                /* Load the stream information.  */
                ret = winnt_scan_data_stream(info->StreamName,
                                             info->StreamNameLength / 2,
                                             info->StreamSize.QuadPart,
                                             inode, ctx);
                if (ret)
                        goto out_free_buf;

                if (info->NextEntryOffset == 0) {
                        /* No more stream information.  */
                        break;
                }
                /* Advance to next stream information.  */
                info = (FILE_STREAM_INFORMATION *)
                                ((u8 *)info + info->NextEntryOffset);
        }
        ret = 0;
        goto out_free_buf;

unnamed_only:
        /* The volume does not support named streams.  Only capture the unnamed
         * data stream.  */
        if (inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
                                   FILE_ATTRIBUTE_REPARSE_POINT))
        {
                ret = 0;
                goto out_free_buf;
        }

        {
                wchar_t stream_name[] = L"::$DATA";
                ret = winnt_scan_data_stream(stream_name, 7, file_size,
                                             inode, ctx);
        }
out_free_buf:
        /* Free buffer if allocated on heap.  */
        if (unlikely(buf != _buf))
                FREE(buf);
        return ret;
}

static u64
extract_starting_lcn(const RETRIEVAL_POINTERS_BUFFER *extents)
{
        if (extents->ExtentCount < 1)
                return 0;

        return extents->Extents[0].Lcn.QuadPart;
}

static noinline_for_stack u64
get_sort_key(HANDLE h)
{
        STARTING_VCN_INPUT_BUFFER in = { .StartingVcn.QuadPart = 0 };
        RETRIEVAL_POINTERS_BUFFER out;

        if (!NT_SUCCESS(winnt_fsctl(h, FSCTL_GET_RETRIEVAL_POINTERS,
                                    &in, sizeof(in), &out, sizeof(out), NULL)))
                return 0;

        return extract_starting_lcn(&out);
}

static void
set_sort_key(struct wim_inode *inode, u64 sort_key)
{
        for (unsigned i = 0; i < inode->i_num_streams; i++) {
                struct wim_inode_stream *strm = &inode->i_streams[i];
                struct blob_descriptor *blob = stream_blob_resolved(strm);
                if (blob && blob->blob_location == BLOB_IN_WINDOWS_FILE)
                        blob->windows_file->sort_key = sort_key;
        }
}

static inline bool
should_try_to_use_wimboot_hash(const struct wim_inode *inode,
                               const struct winnt_scan_ctx *ctx)
{
        /* Directories and encrypted files aren't valid for external backing. */
        if (inode->i_attributes & (FILE_ATTRIBUTE_DIRECTORY |
                                   FILE_ATTRIBUTE_ENCRYPTED))
                return false;

        /* If the file is a reparse point, then try the hash fixup if it's a WOF
         * reparse point and we're in WIMBOOT mode.  Otherwise, try the hash
         * fixup if WOF may be attached. */
        if (inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT)
                return (inode->i_reparse_tag == WIM_IO_REPARSE_TAG_WOF) &&
                        (ctx->params->add_flags & WIMLIB_ADD_FLAG_WIMBOOT);
        return !ctx->wof_not_attached;
}

/*
 * This function implements an optimization for capturing files from a
 * filesystem with a backing WIM(s).  If a file is WIM-backed, then we can
 * retrieve the SHA-1 message digest of its original contents from its reparse
 * point.  This may eliminate the need to read the file's data and/or allow the
 * file's data to be immediately deduplicated with existing data in the WIM.
 *
 * If WOF is attached, then this function is merely an optimization, but
 * potentially a very effective one.  If WOF is detached, then this function
 * really causes WIM-backed files to be, effectively, automatically
 * "dereferenced" when possible; the unnamed data stream is updated to reference
 * the original contents and the reparse point is removed.
 *
 * This function returns 0 if the fixup succeeded or was intentionally not
 * executed.  Otherwise it returns an error code.
 */
static noinline_for_stack int
try_to_use_wimboot_hash(HANDLE h, struct wim_inode *inode,
                        struct winnt_scan_ctx *ctx)
{
        struct blob_table *blob_table = ctx->params->blob_table;
        struct wim_inode_stream *reparse_strm = NULL;
        struct wim_inode_stream *strm;
        struct blob_descriptor *blob;
        u8 hash[SHA1_HASH_SIZE];
        int ret;

        if (inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
                struct reparse_buffer_disk rpbuf;
                struct {
                        struct wof_external_info wof_info;
                        struct wim_provider_rpdata wim_info;
                } *rpdata = (void *)rpbuf.rpdata;
                struct blob_descriptor *reparse_blob;

                /* The file has a WOF reparse point, so WOF must be detached.
                 * We can read the reparse point directly.  */
                ctx->wof_not_attached = true;
                reparse_strm = inode_get_unnamed_stream(inode, STREAM_TYPE_REPARSE_POINT);
                reparse_blob = stream_blob_resolved(reparse_strm);

                if (!reparse_blob || reparse_blob->size < sizeof(*rpdata))
                        return 0;  /* Not a WIM-backed file  */

                ret = read_blob_into_buf(reparse_blob, rpdata);
                if (ret)
                        return ret;

                if (rpdata->wof_info.version != WOF_CURRENT_VERSION ||
                    rpdata->wof_info.provider != WOF_PROVIDER_WIM ||
                    rpdata->wim_info.version != 2)
                        return 0;  /* Not a WIM-backed file  */

                /* Okay, this is a WIM backed file.  Get its SHA-1 hash.  */
                copy_hash(hash, rpdata->wim_info.unnamed_data_stream_hash);
        } else {
                struct {
                        struct wof_external_info wof_info;
                        struct wim_provider_external_info wim_info;
                } out;
                NTSTATUS status;

                /* WOF may be attached.  Try reading this file's external
                 * backing info.  */
                status = winnt_fsctl(h, FSCTL_GET_EXTERNAL_BACKING,
                                     NULL, 0, &out, sizeof(out), NULL);

                /* Is WOF not attached?  */
                if (status == STATUS_INVALID_DEVICE_REQUEST ||
                    status == STATUS_NOT_SUPPORTED) {
                        ctx->wof_not_attached = true;
                        return 0;
                }

                /* Is this file not externally backed?  */
                if (status == STATUS_OBJECT_NOT_EXTERNALLY_BACKED)
                        return 0;

                /* Does this file have an unknown type of external backing that
                 * needed a larger information buffer?  */
                if (status == STATUS_BUFFER_TOO_SMALL)
                        return 0;

                /* Was there some other failure?  */
                if (status != STATUS_SUCCESS) {
                        winnt_error(status,
                                    L"\"%ls\": FSCTL_GET_EXTERNAL_BACKING failed",
                                    printable_path(ctx));
                        return WIMLIB_ERR_STAT;
                }

                /* Is this file backed by a WIM?  */
                if (out.wof_info.version != WOF_CURRENT_VERSION ||
                    out.wof_info.provider != WOF_PROVIDER_WIM ||
                    out.wim_info.version != WIM_PROVIDER_CURRENT_VERSION)
                        return 0;

                /* Okay, this is a WIM backed file.  Get its SHA-1 hash.  */
                copy_hash(hash, out.wim_info.unnamed_data_stream_hash);
        }

        /* If the file's unnamed data stream is nonempty, then fill in its hash
         * and deduplicate it if possible.
         *
         * With WOF detached, we require that the blob *must* de-duplicable for
         * any action can be taken, since without WOF we can't fall back to
         * getting the "dereferenced" data by reading the stream (the real
         * stream is sparse and contains all zeroes).  */
        strm = inode_get_unnamed_data_stream(inode);
        if (strm && (blob = stream_blob_resolved(strm))) {
                struct blob_descriptor **back_ptr;

                if (reparse_strm && !lookup_blob(blob_table, hash))
                        return 0;
                back_ptr = retrieve_pointer_to_unhashed_blob(blob);
                copy_hash(blob->hash, hash);
                if (after_blob_hashed(blob, back_ptr, blob_table) != blob)
                        free_blob_descriptor(blob);
        }

        /* Remove the reparse point, if present.  */
        if (reparse_strm) {
                inode_remove_stream(inode, reparse_strm, blob_table);
                inode->i_attributes &= ~(FILE_ATTRIBUTE_REPARSE_POINT |
                                         FILE_ATTRIBUTE_SPARSE_FILE);
                if (inode->i_attributes == 0)
                        inode->i_attributes = FILE_ATTRIBUTE_NORMAL;
        }

        return 0;
}

struct file_info {
        u32 attributes;
        u32 num_links;
        u64 creation_time;
        u64 last_write_time;
        u64 last_access_time;
        u64 ino;
        u64 end_of_file;
        u32 ea_size;
};

static noinline_for_stack NTSTATUS
get_file_info(HANDLE h, struct file_info *info)
{
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;
        FILE_ALL_INFORMATION all_info;

        status = NtQueryInformationFile(h, &iosb, &all_info, sizeof(all_info),
                                        FileAllInformation);

        if (unlikely(!NT_SUCCESS(status) && status != STATUS_BUFFER_OVERFLOW))
                return status;

        info->attributes = all_info.BasicInformation.FileAttributes;
        info->num_links = all_info.StandardInformation.NumberOfLinks;
        info->creation_time = all_info.BasicInformation.CreationTime.QuadPart;
        info->last_write_time = all_info.BasicInformation.LastWriteTime.QuadPart;
        info->last_access_time = all_info.BasicInformation.LastAccessTime.QuadPart;
        info->ino = all_info.InternalInformation.IndexNumber.QuadPart;
        info->end_of_file = all_info.StandardInformation.EndOfFile.QuadPart;
        info->ea_size = all_info.EaInformation.EaSize;
        return STATUS_SUCCESS;
}

static void
get_volume_information(HANDLE h, struct winnt_scan_ctx *ctx)
{
        u8 _attr_info[sizeof(FILE_FS_ATTRIBUTE_INFORMATION) + 128] _aligned_attribute(8);
        FILE_FS_ATTRIBUTE_INFORMATION *attr_info = (void *)_attr_info;
        FILE_FS_VOLUME_INFORMATION vol_info;
        struct file_info file_info;
        IO_STATUS_BLOCK iosb;
        NTSTATUS status;

        /* Get volume flags  */
        status = NtQueryVolumeInformationFile(h, &iosb, attr_info,
                                              sizeof(_attr_info),
                                              FileFsAttributeInformation);
        if (NT_SUCCESS(status)) {
                ctx->vol_flags = attr_info->FileSystemAttributes;
                ctx->is_ntfs = (attr_info->FileSystemNameLength == 4 * sizeof(wchar_t)) &&
                                !wmemcmp(attr_info->FileSystemName, L"NTFS", 4);
        } else {
                winnt_warning(status, L"\"%ls\": Can't get volume attributes",
                              printable_path(ctx));
        }

        /* Get volume ID.  */
        status = NtQueryVolumeInformationFile(h, &iosb, &vol_info,
                                              sizeof(vol_info),
                                              FileFsVolumeInformation);
        if ((NT_SUCCESS(status) || status == STATUS_BUFFER_OVERFLOW) &&
            (iosb.Information >= offsetof(FILE_FS_VOLUME_INFORMATION,
                                          VolumeSerialNumber) +
             sizeof(vol_info.VolumeSerialNumber)))
        {
                ctx->params->capture_root_dev = vol_info.VolumeSerialNumber;
        } else {
                winnt_warning(status, L"\"%ls\": Can't get volume ID",
                              printable_path(ctx));
        }

        /* Get inode number.  */
        status = get_file_info(h, &file_info);
        if (NT_SUCCESS(status)) {
                ctx->params->capture_root_ino = file_info.ino;
        } else {
                winnt_warning(status, L"\"%ls\": Can't get file information",
                              printable_path(ctx));
        }
}

static int
winnt_build_dentry_tree(struct wim_dentry **root_ret,
                        HANDLE cur_dir,
                        const wchar_t *relative_path,
                        size_t relative_path_nchars,
                        const wchar_t *filename,
                        struct winnt_scan_ctx *ctx,
                        bool recursive)
{
        struct wim_dentry *root = NULL;
        struct wim_inode *inode = NULL;
        HANDLE h = NULL;
        int ret;
        NTSTATUS status;
        struct file_info file_info;
        u64 sort_key;

        ret = try_exclude(ctx->params);
        if (unlikely(ret < 0)) /* Excluded? */
                goto out_progress;
        if (unlikely(ret > 0)) /* Error? */
                goto out;

        /* Open the file with permission to read metadata.  Although we will
         * later need a handle with FILE_LIST_DIRECTORY permission (or,
         * equivalently, FILE_READ_DATA; they're the same numeric value) if the
         * file is a directory, it can significantly slow things down to request
         * this permission on all nondirectories.  Perhaps it causes Windows to
         * start prefetching the file contents...  */
        status = winnt_openat(cur_dir, relative_path, relative_path_nchars,
                              FILE_READ_ATTRIBUTES | FILE_READ_EA |
                                READ_CONTROL | ACCESS_SYSTEM_SECURITY,
                              &h);
        if (unlikely(!NT_SUCCESS(status))) {
                if (status == STATUS_DELETE_PENDING) {
                        WARNING("\"%ls\": Deletion pending; skipping file",
                                printable_path(ctx));
                        ret = 0;
                        goto out;
                }
                if (status == STATUS_SHARING_VIOLATION) {
                        ERROR("Can't open \"%ls\":\n"
                              "        File is in use by another process! "
                              "Consider using snapshot (VSS) mode.",
                              printable_path(ctx));
                        ret = WIMLIB_ERR_OPEN;
                        goto out;
                }
                winnt_error(status, L"\"%ls\": Can't open file",
                            printable_path(ctx));
                if (status == STATUS_FVE_LOCKED_VOLUME)
                        ret = WIMLIB_ERR_FVE_LOCKED_VOLUME;
                else
                        ret = WIMLIB_ERR_OPEN;
                goto out;
        }

        /* Get information about the file.  */
        status = get_file_info(h, &file_info);
        if (!NT_SUCCESS(status)) {
                winnt_error(status, L"\"%ls\": Can't get file information",
                            printable_path(ctx));
                ret = WIMLIB_ERR_STAT;
                goto out;
        }

        /* Create a WIM dentry with an associated inode, which may be shared.
         *
         * However, we need to explicitly check for directories and files with
         * only 1 link and refuse to hard link them.  This is because Windows
         * has a bug where it can return duplicate File IDs for files and
         * directories on the FAT filesystem.
         *
         * Since we don't follow mount points on Windows, we don't need to query
         * the volume ID per-file.  Just once, for the root, is enough.  But we
         * can't simply pass 0, because then there could be inode collisions
         * among multiple calls to win32_build_dentry_tree() that are scanning
         * files on different volumes.  */
        ret = inode_table_new_dentry(ctx->params->inode_table,
                                     filename,
                                     file_info.ino,
                                     ctx->params->capture_root_dev,
                                     (file_info.num_links <= 1),
                                     &root);
        if (ret)
                goto out;

        /* Get the short (DOS) name of the file.  */
        status = winnt_get_short_name(h, root);

        /* If we can't read the short filename for any reason other than
         * out-of-memory, just ignore the error and assume the file has no short
         * name.  This shouldn't be an issue, since the short names are
         * essentially obsolete anyway.  */
        if (unlikely(status == STATUS_NO_MEMORY)) {
                ret = WIMLIB_ERR_NOMEM;
                goto out;
        }

        inode = root->d_inode;

        if (inode->i_nlink > 1) {
                /* Shared inode (hard link); skip reading per-inode information.
                 */
                goto out_progress;
        }

        inode->i_attributes = file_info.attributes;
        inode->i_creation_time = file_info.creation_time;
        inode->i_last_write_time = file_info.last_write_time;
        inode->i_last_access_time = file_info.last_access_time;

        /* Get the file's security descriptor, unless we are capturing in
         * NO_ACLS mode or the volume does not support security descriptors.  */
        if (!(ctx->params->add_flags & WIMLIB_ADD_FLAG_NO_ACLS)
            && (ctx->vol_flags & FILE_PERSISTENT_ACLS))
        {
                ret = winnt_load_security_descriptor(h, inode, ctx);
                if (ret)
                        goto out;
        }

        /* Get the file's object ID.  */
        ret = winnt_load_object_id(h, inode, ctx);
        if (ret)
                goto out;

        /* Get the file's extended attributes.  */
        if (unlikely(file_info.ea_size != 0)) {
                ret = winnt_load_xattrs(h, inode, ctx, file_info.ea_size);
                if (ret)
                        goto out;
        }

        /* If this is a reparse point, load the reparse data.  */
        if (unlikely(inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
                ret = winnt_load_reparse_data(h, inode, ctx);
                if (ret)
                        goto out;
        }

        sort_key = get_sort_key(h);

        if (unlikely(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)) {
                /* Load information about the raw encrypted data.  This is
                 * needed for any directory or non-directory that has
                 * FILE_ATTRIBUTE_ENCRYPTED set.
                 *
                 * Note: since OpenEncryptedFileRaw() fails with
                 * ERROR_SHARING_VIOLATION if there are any open handles to the
                 * file, we have to close the file and re-open it later if
                 * needed.  */
                NtClose(h);
                h = NULL;
                ret = winnt_scan_efsrpc_raw_data(inode, ctx);
                if (ret)
                        goto out;
        } else {
                /*
                 * Load information about data streams (unnamed and named).
                 *
                 * Skip this step for encrypted files, since the data from
                 * ReadEncryptedFileRaw() already contains all data streams (and
                 * they do in fact all get restored by WriteEncryptedFileRaw().)
                 *
                 * Note: WIMGAPI (as of Windows 8.1) gets wrong and stores both
                 * the EFSRPC data and the named data stream(s)...!
                 */
                ret = winnt_scan_data_streams(h,
                                              inode,
                                              file_info.end_of_file,
                                              ctx);
                if (ret)
                        goto out;
        }

        if (unlikely(should_try_to_use_wimboot_hash(inode, ctx))) {
                ret = try_to_use_wimboot_hash(h, inode, ctx);
                if (ret)
                        goto out;
        }

        set_sort_key(inode, sort_key);

        if (inode_is_directory(inode) && recursive) {

                /* Directory: recurse to children.  */

                /* Re-open the directory with FILE_LIST_DIRECTORY access.  */
                if (h) {
                        NtClose(h);
                        h = NULL;
                }
                status = winnt_openat(cur_dir, relative_path,
                                      relative_path_nchars, FILE_LIST_DIRECTORY,
                                      &h);
                if (!NT_SUCCESS(status)) {
                        winnt_error(status, L"\"%ls\": Can't open directory",
                                    printable_path(ctx));
                        ret = WIMLIB_ERR_OPEN;
                        goto out;
                }
                ret = winnt_recurse_directory(h, root, ctx);
                if (ret)
                        goto out;
        }

out_progress:
        ret = 0;
        if (recursive) { /* if !recursive, caller handles progress */
                if (likely(root))
                        ret = do_scan_progress(ctx->params,
                                               WIMLIB_SCAN_DENTRY_OK, inode);
                else
                        ret = do_scan_progress(ctx->params,
                                               WIMLIB_SCAN_DENTRY_EXCLUDED,
                                               NULL);
        }
out:
        if (likely(h))
                NtClose(h);
        if (unlikely(ret)) {
                free_dentry_tree(root, ctx->params->blob_table);
                root = NULL;
                ret = report_scan_error(ctx->params, ret);
        }
        *root_ret = root;
        return ret;
}

static void
winnt_do_scan_warnings(const wchar_t *path, const struct winnt_scan_ctx *ctx)
{
        if (likely(ctx->num_get_sacl_priv_notheld == 0 &&
                   ctx->num_get_sd_access_denied == 0))
                return;

        WARNING("Scan of \"%ls\" complete, but with one or more warnings:", path);
        if (ctx->num_get_sacl_priv_notheld != 0) {
                WARNING("- Could not capture SACL (System Access Control List)\n"
                        "            on %lu files or directories.",
                        ctx->num_get_sacl_priv_notheld);
        }
        if (ctx->num_get_sd_access_denied != 0) {
                WARNING("- Could not capture security descriptor at all\n"
                        "            on %lu files or directories.",
                        ctx->num_get_sd_access_denied);
        }
        WARNING("To fully capture all security descriptors, run the program\n"
                "          with Administrator rights.");
}

/*----------------------------------------------------------------------------*
 *                         Fast MFT scan implementation                       *
 *----------------------------------------------------------------------------*/

#define ENABLE_FAST_MFT_SCAN    1

#ifdef ENABLE_FAST_MFT_SCAN

typedef struct {
        u64 StartingCluster;
        u64 ClusterCount;
} CLUSTER_RANGE;

typedef struct {
        u64 StartingFileReferenceNumber;
        u64 EndingFileReferenceNumber;
} FILE_REFERENCE_RANGE;

/* The FSCTL_QUERY_FILE_LAYOUT ioctl.  This ioctl can be used on Windows 8 and
 * later to scan the MFT of an NTFS volume.  */
#define FSCTL_QUERY_FILE_LAYOUT         CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 157, METHOD_NEITHER, FILE_ANY_ACCESS)

/* The input to FSCTL_QUERY_FILE_LAYOUT  */
typedef struct {
        u32 NumberOfPairs;
#define QUERY_FILE_LAYOUT_RESTART                                       0x00000001
#define QUERY_FILE_LAYOUT_INCLUDE_NAMES                                 0x00000002
#define QUERY_FILE_LAYOUT_INCLUDE_STREAMS                               0x00000004
#define QUERY_FILE_LAYOUT_INCLUDE_EXTENTS                               0x00000008
#define QUERY_FILE_LAYOUT_INCLUDE_EXTRA_INFO                            0x00000010
#define QUERY_FILE_LAYOUT_INCLUDE_STREAMS_WITH_NO_CLUSTERS_ALLOCATED    0x00000020
        u32 Flags;
#define QUERY_FILE_LAYOUT_FILTER_TYPE_NONE              0
#define QUERY_FILE_LAYOUT_FILTER_TYPE_CLUSTERS          1
#define QUERY_FILE_LAYOUT_FILTER_TYPE_FILEID            2
#define QUERY_FILE_LAYOUT_NUM_FILTER_TYPES              3
        u32 FilterType;
        u32 Reserved;
        union {
                CLUSTER_RANGE ClusterRanges[1];
                FILE_REFERENCE_RANGE FileReferenceRanges[1];
        } Filter;
} QUERY_FILE_LAYOUT_INPUT;

/* The header of the buffer returned by FSCTL_QUERY_FILE_LAYOUT  */
typedef struct {
        u32 FileEntryCount;
        u32 FirstFileOffset;
#define QUERY_FILE_LAYOUT_SINGLE_INSTANCED                              0x00000001
        u32 Flags;
        u32 Reserved;
} QUERY_FILE_LAYOUT_OUTPUT;

/* Inode information returned by FSCTL_QUERY_FILE_LAYOUT  */
typedef struct {
        u32 Version;
        u32 NextFileOffset;
        u32 Flags;
        u32 FileAttributes;
        u64 FileReferenceNumber;
        u32 FirstNameOffset;
        u32 FirstStreamOffset;
        u32 ExtraInfoOffset;
        u32 Reserved;
} FILE_LAYOUT_ENTRY;

/* Extra inode information returned by FSCTL_QUERY_FILE_LAYOUT  */
typedef struct {
        struct {
                u64 CreationTime;
                u64 LastAccessTime;
                u64 LastWriteTime;
                u64 ChangeTime;
                u32 FileAttributes;
        } BasicInformation;
        u32 OwnerId;
        u32 SecurityId;
        s64 Usn;
} FILE_LAYOUT_INFO_ENTRY;

/* Filename (or dentry) information returned by FSCTL_QUERY_FILE_LAYOUT  */
typedef struct {
        u32 NextNameOffset;
#define FILE_LAYOUT_NAME_ENTRY_PRIMARY  0x00000001
#define FILE_LAYOUT_NAME_ENTRY_DOS      0x00000002
        u32 Flags;
        u64 ParentFileReferenceNumber;
        u32 FileNameLength;
        u32 Reserved;
        wchar_t FileName[1];
} FILE_LAYOUT_NAME_ENTRY;

/* Stream information returned by FSCTL_QUERY_FILE_LAYOUT  */
typedef struct {
        u32 Version;
        u32 NextStreamOffset;
#define STREAM_LAYOUT_ENTRY_IMMOVABLE                   0x00000001
#define STREAM_LAYOUT_ENTRY_PINNED                      0x00000002
#define STREAM_LAYOUT_ENTRY_RESIDENT                    0x00000004
#define STREAM_LAYOUT_ENTRY_NO_CLUSTERS_ALLOCATED       0x00000008
        u32 Flags;
        u32 ExtentInformationOffset;
        u64 AllocationSize;
        u64 EndOfFile;
        u64 Reserved;
        u32 AttributeFlags;
        u32 StreamIdentifierLength;
        wchar_t StreamIdentifier[1];
} STREAM_LAYOUT_ENTRY;


typedef struct {
#define STREAM_EXTENT_ENTRY_AS_RETRIEVAL_POINTERS       0x00000001
#define STREAM_EXTENT_ENTRY_ALL_EXTENTS                 0x00000002
        u32 Flags;
        union {
                RETRIEVAL_POINTERS_BUFFER RetrievalPointers;
        } ExtentInformation;
} STREAM_EXTENT_ENTRY;

/* Extract the MFT number part of the full inode number  */
#define NTFS_MFT_NO(ref)        ((ref) & (((u64)1 << 48) - 1))

/* Is the file the root directory of the NTFS volume?  The root directory always
 * occupies MFT record 5.  */
#define NTFS_IS_ROOT_FILE(ino)  (NTFS_MFT_NO(ino) == 5)

/* Is the file a special NTFS file, other than the root directory?  The special
 * files are the first 16 records in the MFT.  */
#define NTFS_IS_SPECIAL_FILE(ino)                       \
        (NTFS_MFT_NO(ino) <= 15 && !NTFS_IS_ROOT_FILE(ino))

#define NTFS_SPECIAL_STREAM_OBJECT_ID           0x00000001
#define NTFS_SPECIAL_STREAM_EA                  0x00000002
#define NTFS_SPECIAL_STREAM_EA_INFORMATION      0x00000004

/* Intermediate inode structure.  This is used to temporarily save information
 * from FSCTL_QUERY_FILE_LAYOUT before creating the full 'struct wim_inode'.  */
struct ntfs_inode {
        struct avl_tree_node index_node;
        u64 ino;
        u64 creation_time;
        u64 last_access_time;
        u64 last_write_time;
        u64 starting_lcn;
        u32 attributes;
        u32 security_id;
        u32 num_aliases;
        u32 num_streams;
        u32 special_streams;
        u32 first_stream_offset;
        struct ntfs_dentry *first_child;
        wchar_t short_name[13];
};

/* Intermediate dentry structure.  This is used to temporarily save information
 * from FSCTL_QUERY_FILE_LAYOUT before creating the full 'struct wim_dentry'. */
struct ntfs_dentry {
        u32 offset_from_inode : 31;
        u32 is_primary : 1;
        union {
                /* Note: build_children_lists() replaces 'parent_ino' with
                 * 'next_child'.  */
                u64 parent_ino;
                struct ntfs_dentry *next_child;
        };
        wchar_t name[0];
};

/* Intermediate stream structure.  This is used to temporarily save information
 * from FSCTL_QUERY_FILE_LAYOUT before creating the full 'struct
 * wim_inode_stream'.  */
struct ntfs_stream {
        u64 size;
        wchar_t name[0];
};

/* Map of all known NTFS inodes, keyed by inode number  */
struct ntfs_inode_map {
        struct avl_tree_node *root;
};

#define NTFS_INODE(node)                                \
        avl_tree_entry((node), struct ntfs_inode, index_node)

#define SKIP_ALIGNED(p, size)   ((void *)(p) + ALIGN((size), 8))

/* Get a pointer to the first dentry of the inode.  */
#define FIRST_DENTRY(ni) SKIP_ALIGNED((ni), sizeof(struct ntfs_inode))

/* Get a pointer to the first stream of the inode.  */
#define FIRST_STREAM(ni) ((const void *)ni + ni->first_stream_offset)

/* Advance to the next dentry of the inode.  */
#define NEXT_DENTRY(nd)  SKIP_ALIGNED((nd), sizeof(struct ntfs_dentry) +   \
                                (wcslen((nd)->name) + 1) * sizeof(wchar_t))

/* Advance to the next stream of the inode.  */
#define NEXT_STREAM(ns)  SKIP_ALIGNED((ns), sizeof(struct ntfs_stream) +   \
                                (wcslen((ns)->name) + 1) * sizeof(wchar_t))

static int
_avl_cmp_ntfs_inodes(const struct avl_tree_node *node1,
                     const struct avl_tree_node *node2)
{
        return cmp_u64(NTFS_INODE(node1)->ino, NTFS_INODE(node2)->ino);
}

/* Adds an NTFS inode to the map.  */
static void
ntfs_inode_map_add_inode(struct ntfs_inode_map *map, struct ntfs_inode *ni)
{
        if (avl_tree_insert(&map->root, &ni->index_node, _avl_cmp_ntfs_inodes)) {
                WARNING("Inode 0x%016"PRIx64" is a duplicate!", ni->ino);
                FREE(ni);
        }
}

/* Find an ntfs_inode in the map by inode number.  Returns NULL if not found. */
static struct ntfs_inode *
ntfs_inode_map_lookup(struct ntfs_inode_map *map, u64 ino)
{
        struct ntfs_inode tmp;
        struct avl_tree_node *res;

        tmp.ino = ino;
        res = avl_tree_lookup_node(map->root, &tmp.index_node, _avl_cmp_ntfs_inodes);
        if (!res)
                return NULL;
        return NTFS_INODE(res);
}

/* Remove an ntfs_inode from the map and free it.  */
static void
ntfs_inode_map_remove(struct ntfs_inode_map *map, struct ntfs_inode *ni)
{
        avl_tree_remove(&map->root, &ni->index_node);
        FREE(ni);
}

/* Free all ntfs_inodes in the map.  */
static void
ntfs_inode_map_destroy(struct ntfs_inode_map *map)
{
        struct ntfs_inode *ni;

        avl_tree_for_each_in_postorder(ni, map->root, struct ntfs_inode, index_node)
                FREE(ni);
}

static bool
file_has_streams(const FILE_LAYOUT_ENTRY *file)
{
        return (file->FirstStreamOffset != 0) &&
                !(file->FileAttributes & FILE_ATTRIBUTE_ENCRYPTED);
}

static bool
is_valid_name_entry(const FILE_LAYOUT_NAME_ENTRY *name)
{
        return name->FileNameLength > 0 &&
                name->FileNameLength % 2 == 0 &&
                !wmemchr(name->FileName, L'\0', name->FileNameLength / 2) &&
                (!(name->Flags & FILE_LAYOUT_NAME_ENTRY_DOS) ||
                 name->FileNameLength <= 24);
}

/* Validate the FILE_LAYOUT_NAME_ENTRYs of the specified file and compute the
 * total length in bytes of the ntfs_dentry structures needed to hold the name
 * information.  */
static int
validate_names_and_compute_total_length(const FILE_LAYOUT_ENTRY *file,
                                        size_t *total_length_ret)
{
        const FILE_LAYOUT_NAME_ENTRY *name =
                (const void *)file + file->FirstNameOffset;
        size_t total = 0;
        size_t num_long_names = 0;

        for (;;) {
                if (unlikely(!is_valid_name_entry(name))) {
                        ERROR("Invalid FILE_LAYOUT_NAME_ENTRY! "
                              "FileReferenceNumber=0x%016"PRIx64", "
                              "FileNameLength=%"PRIu32", "
                              "FileName=%.*ls, Flags=0x%08"PRIx32,
                              file->FileReferenceNumber,
                              name->FileNameLength,
                              (int)(name->FileNameLength / 2),
                              name->FileName, name->Flags);
                        return WIMLIB_ERR_UNSUPPORTED;
                }
                if (name->Flags != FILE_LAYOUT_NAME_ENTRY_DOS) {
                        num_long_names++;
                        total += ALIGN(sizeof(struct ntfs_dentry) +
                                       name->FileNameLength + sizeof(wchar_t),
                                       8);
                }
                if (name->NextNameOffset == 0)
                        break;
                name = (const void *)name + name->NextNameOffset;
        }

        if (unlikely(num_long_names == 0)) {
                ERROR("Inode 0x%016"PRIx64" has no long names!",
                      file->FileReferenceNumber);
                return WIMLIB_ERR_UNSUPPORTED;
        }

        *total_length_ret = total;
        return 0;
}

static bool
is_valid_stream_entry(const STREAM_LAYOUT_ENTRY *stream)
{
        return stream->StreamIdentifierLength % 2 == 0 &&
                !wmemchr(stream->StreamIdentifier , L'\0',
                         stream->StreamIdentifierLength / 2);
}

/* assumes that 'id' is a wide string literal */
#define stream_has_identifier(stream, id)                               \
        ((stream)->StreamIdentifierLength == sizeof(id) - 2 &&          \
         !memcmp((stream)->StreamIdentifier, id, sizeof(id) - 2))
/*
 * If the specified STREAM_LAYOUT_ENTRY represents a DATA stream as opposed to
 * some other type of NTFS stream such as a STANDARD_INFORMATION stream, return
 * true and set *stream_name_ret and *stream_name_nchars_ret to specify just the
 * stream name.  For example, ":foo:$DATA" would become "foo" with length 3
 * characters.  Otherwise return false.
 */
static bool
use_stream(const FILE_LAYOUT_ENTRY *file, const STREAM_LAYOUT_ENTRY *stream,
           const wchar_t **stream_name_ret, size_t *stream_name_nchars_ret)
{
        const wchar_t *stream_name;
        size_t stream_name_nchars;

        if (stream->StreamIdentifierLength == 0) {
                /* The unnamed data stream may be given as an empty string
                 * rather than as "::$DATA".  Handle it both ways.  */
                stream_name = L"";
                stream_name_nchars = 0;
        } else if (!get_data_stream_name(stream->StreamIdentifier,
                                         stream->StreamIdentifierLength / 2,
                                         &stream_name, &stream_name_nchars))
                return false;

        /* Skip the unnamed data stream for directories.  */
        if (stream_name_nchars == 0 &&
            (file->FileAttributes & FILE_ATTRIBUTE_DIRECTORY))
                return false;

        *stream_name_ret = stream_name;
        *stream_name_nchars_ret = stream_name_nchars;
        return true;
}

/* Validate the STREAM_LAYOUT_ENTRYs of the specified file and compute the total
 * length in bytes of the ntfs_stream structures needed to hold the stream
 * information.  In addition, set *special_streams_ret to a bitmask of special
 * stream types that were found.  */
static int
validate_streams_and_compute_total_length(const FILE_LAYOUT_ENTRY *file,
                                          size_t *total_length_ret,
                                          u32 *special_streams_ret)
{
        const STREAM_LAYOUT_ENTRY *stream =
                (const void *)file + file->FirstStreamOffset;
        size_t total = 0;
        u32 special_streams = 0;

        for (;;) {
                const wchar_t *name;
                size_t name_nchars;

                if (unlikely(!is_valid_stream_entry(stream))) {
                        WARNING("Invalid STREAM_LAYOUT_ENTRY! "
                                "FileReferenceNumber=0x%016"PRIx64", "
                                "StreamIdentifierLength=%"PRIu32", "
                                "StreamIdentifier=%.*ls",
                                file->FileReferenceNumber,
                                stream->StreamIdentifierLength,
                                (int)(stream->StreamIdentifierLength / 2),
                                stream->StreamIdentifier);
                        return WIMLIB_ERR_UNSUPPORTED;
                }

                if (use_stream(file, stream, &name, &name_nchars)) {
                        total += ALIGN(sizeof(struct ntfs_stream) +
                                       (name_nchars + 1) * sizeof(wchar_t), 8);
                } else if (stream_has_identifier(stream, L"::$OBJECT_ID")) {
                        special_streams |= NTFS_SPECIAL_STREAM_OBJECT_ID;
                } else if (stream_has_identifier(stream, L"::$EA")) {
                        special_streams |= NTFS_SPECIAL_STREAM_EA;
                } else if (stream_has_identifier(stream, L"::$EA_INFORMATION")) {
                        special_streams |= NTFS_SPECIAL_STREAM_EA_INFORMATION;
                }
                if (stream->NextStreamOffset == 0)
                        break;
                stream = (const void *)stream + stream->NextStreamOffset;
        }

        *total_length_ret = total;
        *special_streams_ret = special_streams;
        return 0;
}

static void *
load_name_information(const FILE_LAYOUT_ENTRY *file, struct ntfs_inode *ni,
                      void *p)
{
        const FILE_LAYOUT_NAME_ENTRY *name =
                (const void *)file + file->FirstNameOffset;
        for (;;) {
                struct ntfs_dentry *nd = p;
                /* Note that a name may be just a short (DOS) name, just a long
                 * name, or both a short name and a long name.  If there is a
                 * short name, one name should also be marked as "primary" to
                 * indicate which long name the short name is associated with.
                 * Also, there should be at most one short name per inode.  */
                if (name->Flags & FILE_LAYOUT_NAME_ENTRY_DOS) {
                        memcpy(ni->short_name,
                               name->FileName, name->FileNameLength);
                        ni->short_name[name->FileNameLength / 2] = L'\0';
                }
                if (name->Flags != FILE_LAYOUT_NAME_ENTRY_DOS) {
                        ni->num_aliases++;
                        nd->offset_from_inode = (u8 *)nd - (u8 *)ni;
                        nd->is_primary = ((name->Flags &
                                           FILE_LAYOUT_NAME_ENTRY_PRIMARY) != 0);
                        nd->parent_ino = name->ParentFileReferenceNumber;
                        memcpy(nd->name, name->FileName, name->FileNameLength);
                        nd->name[name->FileNameLength / 2] = L'\0';
                        p += ALIGN(sizeof(struct ntfs_dentry) +
                                   name->FileNameLength + sizeof(wchar_t), 8);
                }
                if (name->NextNameOffset == 0)
                        break;
                name = (const void *)name + name->NextNameOffset;
        }
        return p;
}

static u64
load_starting_lcn(const STREAM_LAYOUT_ENTRY *stream)
{
        const STREAM_EXTENT_ENTRY *entry;

        if (stream->ExtentInformationOffset == 0)
                return 0;

        entry = (const void *)stream + stream->ExtentInformationOffset;

        if (!(entry->Flags & STREAM_EXTENT_ENTRY_AS_RETRIEVAL_POINTERS))
                return 0;

        return extract_starting_lcn(&entry->ExtentInformation.RetrievalPointers);
}

static void *
load_stream_information(const FILE_LAYOUT_ENTRY *file, struct ntfs_inode *ni,
                        void *p)
{
        const STREAM_LAYOUT_ENTRY *stream =
                (const void *)file + file->FirstStreamOffset;
        const u32 first_stream_offset = (const u8 *)p - (const u8 *)ni;
        for (;;) {
                struct ntfs_stream *ns = p;
                const wchar_t *name;
                size_t name_nchars;

                if (use_stream(file, stream, &name, &name_nchars)) {
                        ni->first_stream_offset = first_stream_offset;
                        ni->num_streams++;
                        if (name_nchars == 0)
                                ni->starting_lcn = load_starting_lcn(stream);
                        ns->size = stream->EndOfFile;
                        wmemcpy(ns->name, name, name_nchars);
                        ns->name[name_nchars] = L'\0';
                        p += ALIGN(sizeof(struct ntfs_stream) +
                                   (name_nchars + 1) * sizeof(wchar_t), 8);
                }
                if (stream->NextStreamOffset == 0)
                        break;
                stream = (const void *)stream + stream->NextStreamOffset;
        }
        return p;
}

/* Process the information for a file given by FSCTL_QUERY_FILE_LAYOUT.  */
static int
load_one_file(const FILE_LAYOUT_ENTRY *file, struct ntfs_inode_map *inode_map)
{
        const FILE_LAYOUT_INFO_ENTRY *info =
                (const void *)file + file->ExtraInfoOffset;
        size_t inode_size;
        struct ntfs_inode *ni;
        size_t n;
        int ret;
        void *p;
        u32 special_streams = 0;

        inode_size = ALIGN(sizeof(struct ntfs_inode), 8);

        /* The root file should have no names, and all other files should have
         * at least one name.  But just in case, we ignore the names of the root
         * file, and we ignore any non-root file with no names.  */
        if (!NTFS_IS_ROOT_FILE(file->FileReferenceNumber)) {
                if (file->FirstNameOffset == 0)
                        return 0;
                ret = validate_names_and_compute_total_length(file, &n);
                if (ret)
                        return ret;
                inode_size += n;
        }

        if (file_has_streams(file)) {
                ret = validate_streams_and_compute_total_length(file, &n,
                                                                &special_streams);
                if (ret)
                        return ret;
                inode_size += n;
        }

        /* To save memory, we allocate the ntfs_dentry's and ntfs_stream's in
         * the same memory block as their ntfs_inode.  */
        ni = CALLOC(1, inode_size);
        if (!ni)
                return WIMLIB_ERR_NOMEM;

        ni->ino = file->FileReferenceNumber;
        ni->attributes = info->BasicInformation.FileAttributes;
        ni->creation_time = info->BasicInformation.CreationTime;
        ni->last_write_time = info->BasicInformation.LastWriteTime;
        ni->last_access_time = info->BasicInformation.LastAccessTime;
        ni->security_id = info->SecurityId;
        ni->special_streams = special_streams;

        p = FIRST_DENTRY(ni);

        if (!NTFS_IS_ROOT_FILE(file->FileReferenceNumber))
                p = load_name_information(file, ni, p);

        if (file_has_streams(file))
                p = load_stream_information(file, ni, p);

        wimlib_assert((u8 *)p - (u8 *)ni == inode_size);

        ntfs_inode_map_add_inode(inode_map, ni);
        return 0;
}

/*
 * Quickly find all files on an NTFS volume by using FSCTL_QUERY_FILE_LAYOUT to
 * scan the MFT.  The NTFS volume is specified by the NT namespace path @path.
 * For each file, allocate an 'ntfs_inode' structure for each file and add it to
 * 'inode_map' keyed by inode number.  Include NTFS special files such as
 * $Bitmap (they will be removed later).
 */
static int
load_files_from_mft(const wchar_t *path, struct ntfs_inode_map *inode_map)
{
        HANDLE h = NULL;
        QUERY_FILE_LAYOUT_INPUT in = (QUERY_FILE_LAYOUT_INPUT) {
                .NumberOfPairs = 0,
                .Flags = QUERY_FILE_LAYOUT_RESTART |
                         QUERY_FILE_LAYOUT_INCLUDE_NAMES |
                         QUERY_FILE_LAYOUT_INCLUDE_STREAMS |
                         QUERY_FILE_LAYOUT_INCLUDE_EXTENTS |
                         QUERY_FILE_LAYOUT_INCLUDE_EXTRA_INFO |
                         QUERY_FILE_LAYOUT_INCLUDE_STREAMS_WITH_NO_CLUSTERS_ALLOCATED,
                .FilterType = QUERY_FILE_LAYOUT_FILTER_TYPE_NONE,
        };
        size_t outsize = 32768;
        QUERY_FILE_LAYOUT_OUTPUT *out = NULL;
        int ret;
        NTSTATUS status;

        status = winnt_open(path, wcslen(path),
                            FILE_READ_DATA | FILE_READ_ATTRIBUTES, &h);
        if (!NT_SUCCESS(status)) {
                ret = -1; /* Silently try standard recursive scan instead  */
                goto out;
        }

        for (;;) {
                /* Allocate a buffer for the output of the ioctl.  */
                out = MALLOC(outsize);
                if (!out) {
                        ret = WIMLIB_ERR_NOMEM;
                        goto out;
                }

                /* Execute FSCTL_QUERY_FILE_LAYOUT until it fails.  */
                while (NT_SUCCESS(status = winnt_fsctl(h,
                                                       FSCTL_QUERY_FILE_LAYOUT,
                                                       &in, sizeof(in),
                                                       out, outsize, NULL)))
                {
                        const FILE_LAYOUT_ENTRY *file =
                                (const void *)out + out->FirstFileOffset;
                        for (;;) {
                                ret = load_one_file(file, inode_map);
                                if (ret)
                                        goto out;
                                if (file->NextFileOffset == 0)
                                        break;
                                file = (const void *)file + file->NextFileOffset;
                        }
                        in.Flags &= ~QUERY_FILE_LAYOUT_RESTART;
                }

                /* Enlarge the buffer if needed.  */
                if (status != STATUS_BUFFER_TOO_SMALL)
                        break;
                FREE(out);
                outsize *= 2;
        }

        /* Normally, FSCTL_QUERY_FILE_LAYOUT fails with STATUS_END_OF_FILE after
         * all files have been enumerated.  */
        if (status != STATUS_END_OF_FILE) {
                if (status == STATUS_INVALID_DEVICE_REQUEST /* old OS */ ||
                    status == STATUS_NOT_SUPPORTED /* Samba volume, WinXP */ ||
                    status == STATUS_INVALID_PARAMETER /* not root directory */ )
                {
                        /* Silently try standard recursive scan instead  */
                        ret = -1;
                } else {
                        winnt_error(status,
                                    L"Error enumerating files on volume \"%ls\"",
                                    path);
                        /* Try standard recursive scan instead  */
                        ret = WIMLIB_ERR_UNSUPPORTED;
                }
                goto out;
        }
        ret = 0;
out:
        FREE(out);
        NtClose(h);
        return ret;
}

/* Build the list of child dentries for each inode in @map.  This is done by
 * iterating through each name of each inode and adding it to its parent's
 * children list.  Note that every name should have a parent, i.e. should belong
 * to some directory.  The root directory does not have any names.  */
static int
build_children_lists(struct ntfs_inode_map *map, struct ntfs_inode **root_ret)
{
        struct ntfs_inode *ni;

        avl_tree_for_each_in_order(ni, map->root, struct ntfs_inode, index_node)
        {
                struct ntfs_dentry *nd;
                u32 n;

                if (NTFS_IS_ROOT_FILE(ni->ino)) {
                        *root_ret = ni;
                        continue;
                }

                n = ni->num_aliases;
                nd = FIRST_DENTRY(ni);
                for (;;) {
                        struct ntfs_inode *parent;

                        parent = ntfs_inode_map_lookup(map, nd->parent_ino);
                        if (unlikely(!parent)) {
                                ERROR("Parent inode 0x%016"PRIx64" of"
                                      "directory entry \"%ls\" (inode "
                                      "0x%016"PRIx64") was missing from the "
                                      "MFT listing!",
                                      nd->parent_ino, nd->name, ni->ino);
                                return WIMLIB_ERR_UNSUPPORTED;
                        }
                        nd->next_child = parent->first_child;
                        parent->first_child = nd;
                        if (!--n)
                                break;
                        nd = NEXT_DENTRY(nd);
                }
        }
        return 0;
}

struct security_map_node {
        struct avl_tree_node index_node;
        u32 disk_security_id;
        u32 wim_security_id;
};

/* Map from disk security IDs to WIM security IDs  */
struct security_map {
        struct avl_tree_node *root;
};

#define SECURITY_MAP_NODE(node)                         \
        avl_tree_entry((node), struct security_map_node, index_node)

static int
_avl_cmp_security_map_nodes(const struct avl_tree_node *node1,
                            const struct avl_tree_node *node2)
{
        return cmp_u32(SECURITY_MAP_NODE(node1)->disk_security_id,
                       SECURITY_MAP_NODE(node2)->disk_security_id);
}

static s32
security_map_lookup(struct security_map *map, u32 disk_security_id)
{
        struct security_map_node tmp;
        const struct avl_tree_node *res;

        if (disk_security_id == 0)  /* No on-disk security ID; uncacheable  */
                return -1;

        tmp.disk_security_id = disk_security_id;
        res = avl_tree_lookup_node(map->root, &tmp.index_node,
                                   _avl_cmp_security_map_nodes);
        if (!res)
                return -1;
        return SECURITY_MAP_NODE(res)->wim_security_id;
}

static int
security_map_insert(struct security_map *map, u32 disk_security_id,
                    u32 wim_security_id)
{
        struct security_map_node *node;

        if (disk_security_id == 0)  /* No on-disk security ID; uncacheable  */
                return 0;

        node = MALLOC(sizeof(*node));
        if (!node)
                return WIMLIB_ERR_NOMEM;

        node->disk_security_id = disk_security_id;
        node->wim_security_id = wim_security_id;
        avl_tree_insert(&map->root, &node->index_node,
                        _avl_cmp_security_map_nodes);
        return 0;
}

static void
security_map_destroy(struct security_map *map)
{
        struct security_map_node *node;

        avl_tree_for_each_in_postorder(node, map->root,
                                       struct security_map_node, index_node)
                FREE(node);
}

/*
 * Turn our temporary NTFS structures into the final WIM structures:
 *
 *      ntfs_inode      => wim_inode
 *      ntfs_dentry     => wim_dentry
 *      ntfs_stream     => wim_inode_stream
 *
 * This also handles things such as exclusions and issuing progress messages.
 * It's similar to winnt_build_dentry_tree(), but this is much faster because
 * almost all information we need is already loaded in memory in the ntfs_*
 * structures.  However, in some cases we still fall back to
 * winnt_build_dentry_tree() and/or opening the file.
 */
static int
generate_wim_structures_recursive(struct wim_dentry **root_ret,
                                  const wchar_t *filename, bool is_primary_name,
                                  struct ntfs_inode *ni,
                                  struct winnt_scan_ctx *ctx,
                                  struct ntfs_inode_map *inode_map,
                                  struct security_map *security_map)
{
        int ret = 0;
        struct wim_dentry *root = NULL;
        struct wim_inode *inode = NULL;
        const struct ntfs_stream *ns;

        /* Completely ignore NTFS special files.  */
        if (NTFS_IS_SPECIAL_FILE(ni->ino))
                goto out;

        /* Fall back to the standard scan for unhandled cases.  Reparse points,
         * in particular, can't be properly handled here because a commonly used
         * filter driver (WOF) hides reparse points from regular filesystem APIs
         * but not from FSCTL_QUERY_FILE_LAYOUT.  */
        if (ni->attributes & (FILE_ATTRIBUTE_REPARSE_POINT |
                              FILE_ATTRIBUTE_ENCRYPTED) ||
            ni->special_streams != 0)
        {
                ret = winnt_build_dentry_tree(&root, NULL,
                                              ctx->params->cur_path,
                                              ctx->params->cur_path_nchars,
                                              filename, ctx, false);
                if (ret) /* Error? */
                        goto out;
                if (!root) /* Excluded? */
                        goto out_progress;
                inode = root->d_inode;
                goto process_children;
        }

        /* Test for exclusion based on path.  */
        ret = try_exclude(ctx->params);
        if (unlikely(ret < 0)) /* Excluded? */
                goto out_progress;
        if (unlikely(ret > 0)) /* Error? */
                goto out;

        /* Create the WIM dentry and possibly a new WIM inode  */
        ret = inode_table_new_dentry(ctx->params->inode_table, filename,
                                     ni->ino, ctx->params->capture_root_dev,
                                     false, &root);
        if (ret)
                goto out;

        inode = root->d_inode;

        /* Set the short name if needed.  */
        if (is_primary_name && *ni->short_name) {
                size_t nbytes = wcslen(ni->short_name) * sizeof(wchar_t);
                root->d_short_name = memdup(ni->short_name,
                                            nbytes + sizeof(wchar_t));
                if (!root->d_short_name) {
                        ret = WIMLIB_ERR_NOMEM;
                        goto out;
                }
                root->d_short_name_nbytes = nbytes;
        }

        if (inode->i_nlink > 1) { /* Already seen this inode?  */
                ret = 0;
                goto out_progress;
        }

        /* The file attributes and timestamps were cached from the MFT.  */
        inode->i_attributes = ni->attributes;
        inode->i_creation_time = ni->creation_time;
        inode->i_last_write_time = ni->last_write_time;
        inode->i_last_access_time = ni->last_access_time;

        /* Set the security descriptor if needed.  */
        if (!(ctx->params->add_flags & WIMLIB_ADD_FLAG_NO_ACLS)) {
                /* Look up the WIM security ID that corresponds to the on-disk
                 * security ID.  */
                s32 wim_security_id =
                        security_map_lookup(security_map, ni->security_id);
                if (likely(wim_security_id >= 0)) {
                        /* The mapping for this security ID is already cached.*/
                        inode->i_security_id = wim_security_id;
                } else {
                        HANDLE h;
                        NTSTATUS status;

                        /* Create a mapping for this security ID and insert it
                         * into the security map.  */

                        status = winnt_open(ctx->params->cur_path,
                                            ctx->params->cur_path_nchars,
                                            READ_CONTROL |
                                                ACCESS_SYSTEM_SECURITY, &h);
                        if (!NT_SUCCESS(status)) {
                                winnt_error(status, L"Can't open \"%ls\" to "
                                            "read security descriptor",
                                            printable_path(ctx));
                                ret = WIMLIB_ERR_OPEN;
                                goto out;
                        }
                        ret = winnt_load_security_descriptor(h, inode, ctx);
                        NtClose(h);
                        if (ret)
                                goto out;

                        ret = security_map_insert(security_map, ni->security_id,
                                                  inode->i_security_id);
                        if (ret)
                                goto out;
                }
        }

        /* Add data streams based on the cached information from the MFT.  */
        ns = FIRST_STREAM(ni);
        for (u32 i = 0; i < ni->num_streams; i++) {
                struct windows_file *windows_file;

                /* Reference the stream by path if it's a named data stream, or
                 * if the volume doesn't support "open by file ID", or if the
                 * application hasn't explicitly opted in to "open by file ID".
                 * Otherwise, only save the inode number (file ID).  */
                if (*ns->name ||
                    !(ctx->vol_flags & FILE_SUPPORTS_OPEN_BY_FILE_ID) ||
                    !(ctx->params->add_flags & WIMLIB_ADD_FLAG_FILE_PATHS_UNNEEDED))
                {
                        windows_file = alloc_windows_file(ctx->params->cur_path,
                                                          ctx->params->cur_path_nchars,
                                                          ns->name,
                                                          wcslen(ns->name),
                                                          ctx->snapshot,
                                                          false);
                } else {
                        windows_file = alloc_windows_file_for_file_id(ni->ino,
                                                                      ctx->params->cur_path,
                                                                      ctx->params->root_path_nchars,
                                                                      ctx->snapshot);
                }

                ret = add_stream(inode, windows_file, ns->size,
                                 STREAM_TYPE_DATA, ns->name,
                                 ctx->params->unhashed_blobs);
                if (ret)
                        goto out;
                ns = NEXT_STREAM(ns);
        }

        set_sort_key(inode, ni->starting_lcn);

        /* If processing a directory, then recurse to its children.  In this
         * version there is no need to go to disk, as we already have the list
         * of children cached from the MFT.  */
process_children:
        if (inode_is_directory(inode)) {
                const struct ntfs_dentry *nd = ni->first_child;

                while (nd != NULL) {
                        size_t orig_path_nchars;
                        struct wim_dentry *child;
                        const struct ntfs_dentry *next = nd->next_child;

                        ret = WIMLIB_ERR_NOMEM;
                        if (!pathbuf_append_name(ctx->params, nd->name,
                                                 wcslen(nd->name),
                                                 &orig_path_nchars))
                                goto out;

                        ret = generate_wim_structures_recursive(
                                        &child,
                                        nd->name,
                                        nd->is_primary,
                                        (void *)nd - nd->offset_from_inode,
                                        ctx,
                                        inode_map,
                                        security_map);

                        pathbuf_truncate(ctx->params, orig_path_nchars);

                        if (ret)
                                goto out;

                        attach_scanned_tree(root, child, ctx->params->blob_table);
                        nd = next;
                }
        }

out_progress:
        if (likely(root))
                ret = do_scan_progress(ctx->params, WIMLIB_SCAN_DENTRY_OK, inode);
        else
                ret = do_scan_progress(ctx->params, WIMLIB_SCAN_DENTRY_EXCLUDED, NULL);
out:
        if (--ni->num_aliases == 0) {
                /* Memory usage optimization: when we don't need the ntfs_inode
                 * (and its names and streams) anymore, free it.  */
                ntfs_inode_map_remove(inode_map, ni);
        }
        if (unlikely(ret)) {
                free_dentry_tree(root, ctx->params->blob_table);
                root = NULL;
        }
        *root_ret = root;
        return ret;
}

static int
winnt_build_dentry_tree_fast(struct wim_dentry **root_ret,
                             struct winnt_scan_ctx *ctx)
{
        struct ntfs_inode_map inode_map = { .root = NULL };
        struct security_map security_map = { .root = NULL };
        struct ntfs_inode *root = NULL;
        wchar_t *path = ctx->params->cur_path;
        size_t path_nchars = ctx->params->cur_path_nchars;
        bool adjust_path;
        int ret;

        adjust_path = (path[path_nchars - 1] == L'\\');
        if (adjust_path)
                path[path_nchars - 1] = L'\0';

        ret = load_files_from_mft(path, &inode_map);

        if (adjust_path)
                path[path_nchars - 1] = L'\\';

        if (ret)
                goto out;

        ret = build_children_lists(&inode_map, &root);
        if (ret)
                goto out;

        if (!root) {
                ERROR("The MFT listing for volume \"%ls\" did not include a "
                      "root directory!", path);
                ret = WIMLIB_ERR_UNSUPPORTED;
                goto out;
        }

        root->num_aliases = 1;

        ret = generate_wim_structures_recursive(root_ret, L"", false, root, ctx,
                                                &inode_map, &security_map);
out:
        ntfs_inode_map_destroy(&inode_map);
        security_map_destroy(&security_map);
        return ret;
}

#endif /* ENABLE_FAST_MFT_SCAN */

/*----------------------------------------------------------------------------*
 *                 Entry point for directory tree scans on Windows            *
 *----------------------------------------------------------------------------*/

int
win32_build_dentry_tree(struct wim_dentry **root_ret,
                        const wchar_t *root_disk_path,
                        struct scan_params *params)
{
        struct winnt_scan_ctx ctx = { .params = params };
        UNICODE_STRING ntpath;
        HANDLE h = NULL;
        NTSTATUS status;
        int ret;

        if (params->add_flags & WIMLIB_ADD_FLAG_SNAPSHOT)
                ret = vss_create_snapshot(root_disk_path, &ntpath, &ctx.snapshot);
        else
                ret = win32_path_to_nt_path(root_disk_path, &ntpath);

        if (ret)
                goto out;

        if (ntpath.Length < 4 * sizeof(wchar_t) ||
            wmemcmp(ntpath.Buffer, L"\\??\\", 4))
        {
                ERROR("\"%ls\": unrecognized path format", root_disk_path);
                ret = WIMLIB_ERR_INVALID_PARAM;
        } else {
                ret = pathbuf_init(params, ntpath.Buffer);
        }
        HeapFree(GetProcessHeap(), 0, ntpath.Buffer);
        if (ret)
                goto out;

        status = winnt_open(params->cur_path, params->cur_path_nchars,
                            FILE_READ_ATTRIBUTES, &h);
        if (!NT_SUCCESS(status)) {
                winnt_error(status, L"Can't open \"%ls\"", root_disk_path);
                if (status == STATUS_FVE_LOCKED_VOLUME)
                        ret = WIMLIB_ERR_FVE_LOCKED_VOLUME;
                else
                        ret = WIMLIB_ERR_OPEN;
                goto out;
        }

        get_volume_information(h, &ctx);

        NtClose(h);

#ifdef ENABLE_FAST_MFT_SCAN
        if (ctx.is_ntfs && !_wgetenv(L"WIMLIB_DISABLE_QUERY_FILE_LAYOUT")) {
                ret = winnt_build_dentry_tree_fast(root_ret, &ctx);
                if (ret >= 0 && ret != WIMLIB_ERR_UNSUPPORTED)
                        goto out;
                if (ret >= 0) {
                        WARNING("A problem occurred during the fast MFT scan.\n"
                                "          Falling back to the standard "
                                "recursive directory tree scan.");
                }
        }
#endif
        ret = winnt_build_dentry_tree(root_ret, NULL, params->cur_path,
                                      params->cur_path_nchars, L"", &ctx, true);
out:
        vss_put_snapshot(ctx.snapshot);
        if (ret == 0)
                winnt_do_scan_warnings(root_disk_path, &ctx);
        return ret;
}

#endif /* __WIN32__ */