[wimlib] / src / ntfs-3g_apply.c

/*
 * ntfs-3g_apply.c
 *
 * Apply a WIM image directly to an NTFS volume using libntfs-3g.  Restore as
 * much information as possible, including security data, file attributes, DOS
 * names, and alternate data streams.
 *
 * Note: because NTFS-3g offers inode-based interfaces, we actually don't need
 * to deal with paths at all!  (Other than for error messages.)
 */

/*
 * Copyright (C) 2012, 2013, 2014 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 HAVE_CONFIG_H
#  include "config.h"
#endif

#include <locale.h>
#include <string.h>

#include <ntfs-3g/attrib.h>
#include <ntfs-3g/reparse.h>
#include <ntfs-3g/security.h>

#include "wimlib/assert.h"
#include "wimlib/apply.h"
#include "wimlib/dentry.h"
#include "wimlib/encoding.h"
#include "wimlib/error.h"
#include "wimlib/lookup_table.h"
#include "wimlib/metadata.h"
#include "wimlib/ntfs_3g.h"
#include "wimlib/reparse.h"
#include "wimlib/security.h"
#include "wimlib/security_descriptor.h"

static int
ntfs_3g_get_supported_features(const char *target,
                               struct wim_features *supported_features)
{
        supported_features->archive_files             = 1;
        supported_features->hidden_files              = 1;
        supported_features->system_files              = 1;
        supported_features->compressed_files          = 1;
        supported_features->encrypted_directories     = 1;
        supported_features->not_context_indexed_files = 1;
        supported_features->named_data_streams        = 1;
        supported_features->hard_links                = 1;
        supported_features->reparse_points            = 1;
        supported_features->security_descriptors      = 1;
        supported_features->short_names               = 1;
        supported_features->timestamps                = 1;
        supported_features->case_sensitive_filenames  = 1;
        return 0;
}

struct ntfs_3g_apply_ctx {
        /* Extract flags, the pointer to the WIMStruct, etc.  */
        struct apply_ctx common;

        /* Pointer to the open NTFS volume  */
        ntfs_volume *vol;

        ntfs_attr *open_attrs[MAX_OPEN_STREAMS];
        unsigned num_open_attrs;
        ntfs_inode *open_inodes[MAX_OPEN_STREAMS];
        unsigned num_open_inodes;

        struct reparse_buffer_disk rpbuf;
        u8 *reparse_ptr;

        /* Offset in the stream currently being read  */
        u64 offset;

        unsigned num_reparse_inodes;
        ntfs_inode *ntfs_reparse_inodes[MAX_OPEN_STREAMS];
        struct wim_inode *wim_reparse_inodes[MAX_OPEN_STREAMS];
};

static size_t
sid_size(const wimlib_SID *sid)
{
        return offsetof(wimlib_SID, sub_authority) +
                sizeof(le32) * sid->sub_authority_count;
}

/*
 * sd_fixup - Fix up a Windows NT security descriptor for libntfs-3g.
 *
 * libntfs-3g validates security descriptors before setting them, but old
 * versions contain bugs causing it to reject unusual but valid security
 * descriptors:
 *
 * - Versions before 2013.1.13 reject security descriptors ending with an empty
 *   SACL (System Access Control List).  This bug can be worked around either by
 *   moving the empty SACL earlier in the security descriptor or by removing the
 *   SACL entirely.  The latter work-around is valid because an empty SACL is
 *   equivalent to a "null", or non-existent, SACL.
 * - Versions up to and including 2013.1.13 reject security descriptors ending
 *   with an empty DACL (Discretionary Access Control List).  This is very
 *   similar to the SACL bug and should be fixed in the next release after
 *   2013.1.13.  However, removing the DACL is not a valid workaround because
 *   this changes the meaning of the security descriptor--- an empty DACL allows
 *   no access, whereas a "null" DACL allows all access.
 *
 * If the security descriptor was fixed, this function returns an allocated
 * buffer containing the fixed security descriptor, and its size is updated.
 * Otherwise (or if no memory is available) the original descriptor is returned.
 */
static u8 *
sd_fixup(const u8 *_desc, size_t *size_p)
{
        u32 owner_offset, group_offset, dacl_offset, sacl_offset;
        bool owner_valid, group_valid;
        size_t size = *size_p;
        const wimlib_SECURITY_DESCRIPTOR_RELATIVE *desc =
                        (const wimlib_SECURITY_DESCRIPTOR_RELATIVE*)_desc;
        wimlib_SECURITY_DESCRIPTOR_RELATIVE *desc_new;
        const wimlib_SID *owner, *group, *sid;

        /* Don't attempt to fix clearly invalid security descriptors.  */
        if (size < sizeof(wimlib_SECURITY_DESCRIPTOR_RELATIVE))
                return (u8*)_desc;

        if (le16_to_cpu(desc->control) & wimlib_SE_DACL_PRESENT)
                dacl_offset = le32_to_cpu(desc->dacl_offset);
        else
                dacl_offset = 0;

        if (le16_to_cpu(desc->control) & wimlib_SE_SACL_PRESENT)
                sacl_offset = le32_to_cpu(desc->sacl_offset);
        else
                sacl_offset = 0;

        /* Check if the security descriptor will be affected by one of the bugs.
         * If not, do nothing and return.
         *
         * Note: HAVE_NTFS_MNT_RDONLY is defined if libntfs-3g is
         * version 2013.1.13 or later.  */
        if (!(
        #if !defined(HAVE_NTFS_MNT_RDONLY)
            (sacl_offset != 0 && sacl_offset == size - sizeof(wimlib_ACL)) ||
        #endif
            (dacl_offset != 0 && dacl_offset == size - sizeof(wimlib_ACL))))
                return (u8*)_desc;

        owner_offset = le32_to_cpu(desc->owner_offset);
        group_offset = le32_to_cpu(desc->group_offset);
        owner = (const wimlib_SID*)((const u8*)desc + owner_offset);
        group = (const wimlib_SID*)((const u8*)desc + group_offset);

        /* We'll try to move the owner or group SID to the end of the security
         * descriptor to avoid the bug.  This is only possible if at least one
         * is valid.  */
        owner_valid = (owner_offset != 0) &&
                        (owner_offset % 4 == 0) &&
                        (owner_offset <= size - sizeof(SID)) &&
                        (owner_offset + sid_size(owner) <= size) &&
                        (owner_offset >= sizeof(wimlib_SECURITY_DESCRIPTOR_RELATIVE));
        group_valid = (group_offset != 0) &&
                        (group_offset % 4 == 0) &&
                        (group_offset <= size - sizeof(SID)) &&
                        (group_offset + sid_size(group) <= size) &&
                        (group_offset >= sizeof(wimlib_SECURITY_DESCRIPTOR_RELATIVE));
        if (owner_valid) {
                sid = owner;
        } else if (group_valid) {
                sid = group;
        } else {
                return (u8*)_desc;
        }

        desc_new = MALLOC(size + sid_size(sid));
        if (!desc_new)
                return (u8*)_desc;

        memcpy(desc_new, desc, size);
        if (owner_valid)
                desc_new->owner_offset = cpu_to_le32(size);
        else if (group_valid)
                desc_new->group_offset = cpu_to_le32(size);
        memcpy((u8*)desc_new + size, sid, sid_size(sid));
        *size_p = size + sid_size(sid);
        return (u8*)desc_new;
}

/* Set the security descriptor @desc of size @desc_size on the NTFS inode @ni.
  */
static int
ntfs_3g_set_security_descriptor(ntfs_inode *ni, const void *desc, size_t desc_size)
{
        struct SECURITY_CONTEXT sec_ctx;
        u8 *desc_fixed;
        int ret = 0;

        memset(&sec_ctx, 0, sizeof(sec_ctx));
        sec_ctx.vol = ni->vol;

        desc_fixed = sd_fixup(desc, &desc_size);

        if (ntfs_set_ntfs_acl(&sec_ctx, ni, desc_fixed, desc_size, 0))
                ret = WIMLIB_ERR_SET_SECURITY;

        if (desc_fixed != desc)
                FREE(desc_fixed);

        return ret;
}

static int
ntfs_3g_set_timestamps(ntfs_inode *ni, const struct wim_inode *inode)
{
        u64 times[3] = {
                inode->i_creation_time,
                inode->i_last_write_time,
                inode->i_last_access_time,
        };

        if (ntfs_inode_set_times(ni, (const char *)times, sizeof(times), 0))
                return WIMLIB_ERR_SET_TIMESTAMPS;
        return 0;
}

/* Restore the timestamps on the NTFS inode corresponding to @inode.  */
static int
ntfs_3g_restore_timestamps(ntfs_volume *vol, const struct wim_inode *inode)
{
        ntfs_inode *ni;
        int res;

        ni = ntfs_inode_open(vol, inode->i_mft_no);
        if (!ni)
                goto fail;

        res = ntfs_3g_set_timestamps(ni, inode);

        if (ntfs_inode_close(ni) || res)
                goto fail;

        return 0;

fail:
        ERROR_WITH_ERRNO("Failed to update timestamps of \"%s\" in NTFS volume",
                         dentry_full_path(inode_first_extraction_dentry(inode)));
        return WIMLIB_ERR_SET_TIMESTAMPS;
}

/* Restore the DOS name of the @dentry.
 * This closes both @ni and @dir_ni.
 * If either is NULL, then they are opened temporarily.  */
static int
ntfs_3g_restore_dos_name(ntfs_inode *ni, ntfs_inode *dir_ni,
                         struct wim_dentry *dentry, ntfs_volume *vol)
{
        int ret;
        const char *dos_name;
        size_t dos_name_nbytes;

        /* Note: ntfs_set_ntfs_dos_name() closes both inodes (even if it fails).
         * And it takes in a multibyte string, even though it translates it to
         * UTF-16LE internally... which is annoying because we currently have
         * the UTF-16LE string but not the multibyte string.  */

        ret = utf16le_get_tstr(dentry->short_name, dentry->short_name_nbytes,
                               &dos_name, &dos_name_nbytes);
        if (ret)
                goto out_close;

        if (!dir_ni)
                dir_ni = ntfs_inode_open(vol, dentry->d_parent->d_inode->i_mft_no);
        if (!ni)
                ni = ntfs_inode_open(vol, dentry->d_inode->i_mft_no);
        if (dir_ni && ni) {
                ret = ntfs_set_ntfs_dos_name(ni, dir_ni,
                                             dos_name, dos_name_nbytes, 0);
                dir_ni = NULL;
                ni = NULL;
        } else {
                ret = -1;
        }
        utf16le_put_tstr(dos_name);
        if (ret) {
                ERROR_WITH_ERRNO("Failed to set DOS name of \"%s\" in NTFS "
                                 "volume", dentry_full_path(dentry));
                ret = WIMLIB_ERR_SET_SHORT_NAME;
                goto out_close;
        }

        /* Unlike most other NTFS-3g functions, ntfs_set_ntfs_dos_name()
         * changes the directory's last modification timestamp...
         * Change it back.  */
        return ntfs_3g_restore_timestamps(vol, dentry->d_parent->d_inode);

out_close:
        /* ntfs_inode_close() can take a NULL argument, but it's probably best
         * not to rely on this behavior.  */
        if (ni)
                ntfs_inode_close(ni);
        if (dir_ni)
                ntfs_inode_close(dir_ni);
        return ret;
}

/* Create empty named data streams.
 *
 * Since these won't have 'struct wim_lookup_table_entry's, they won't show up
 * in the call to extract_stream_list().  Hence the need for the special case.
 */
static int
ntfs_3g_create_any_empty_ads(ntfs_inode *ni, const struct wim_inode *inode,
                             const struct ntfs_3g_apply_ctx *ctx)
{
        for (u16 i = 0; i < inode->i_num_ads; i++) {
                const struct wim_ads_entry *entry;

                entry = &inode->i_ads_entries[i];

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

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

                if (ntfs_attr_add(ni, AT_DATA, entry->stream_name,
                                  entry->stream_name_nbytes /
                                        sizeof(utf16lechar),
                                  NULL, 0))
                {
                        ERROR_WITH_ERRNO("Failed to create named data stream "
                                         "of \"%s\"", dentry_full_path(
                                                inode_first_extraction_dentry(inode)));
                        return WIMLIB_ERR_NTFS_3G;
                }
        }
        return 0;
}

/* Set attributes, security descriptor, and timestamps on the NTFS inode @ni.
 */
static int
ntfs_3g_set_metadata(ntfs_inode *ni, const struct wim_inode *inode,
                     const struct ntfs_3g_apply_ctx *ctx)
{
        int extract_flags;
        const struct wim_security_data *sd;
        struct wim_dentry *one_dentry;
        int ret;

        extract_flags = ctx->common.extract_flags;
        sd = wim_get_current_security_data(ctx->common.wim);
        one_dentry = inode_first_extraction_dentry(inode);

        /* Attributes  */
        if (!(extract_flags & WIMLIB_EXTRACT_FLAG_NO_ATTRIBUTES)) {
                u32 attrib = inode->i_attributes;

                attrib &= ~(FILE_ATTRIBUTE_SPARSE_FILE |
                            FILE_ATTRIBUTE_ENCRYPTED);

                if (ntfs_set_ntfs_attrib(ni, (const char *)&attrib,
                                         sizeof(attrib), 0))
                {
                        ERROR_WITH_ERRNO("Failed to set attributes on \"%s\" "
                                         "in NTFS volume",
                                         dentry_full_path(one_dentry));
                        return WIMLIB_ERR_SET_ATTRIBUTES;
                }
        }

        /* Security descriptor  */
        if ((inode->i_security_id >= 0)
            && !(extract_flags & WIMLIB_EXTRACT_FLAG_NO_ACLS))
        {
                const void *desc;
                size_t desc_size;

                desc = sd->descriptors[inode->i_security_id];
                desc_size = sd->sizes[inode->i_security_id];

                ret = ntfs_3g_set_security_descriptor(ni, desc, desc_size);
                if (ret) {
                        if (wimlib_print_errors) {
                                ERROR_WITH_ERRNO("Failed to set security descriptor "
                                                 "on \"%s\" in NTFS volume",
                                                 dentry_full_path(one_dentry));
                                fprintf(wimlib_error_file,
                                        "The security descriptor is: ");
                                print_byte_field(desc, desc_size, wimlib_error_file);
                                fprintf(wimlib_error_file, "\n");
                        }
                        return ret;
                }
        }

        /* Timestamps  */
        ret = ntfs_3g_set_timestamps(ni, inode);
        if (ret) {
                ERROR_WITH_ERRNO("Failed to set timestamps on \"%s\" "
                                 "in NTFS volume",
                                 dentry_full_path(one_dentry));
                return ret;
        }
        return 0;
}

/* Recursively creates all the subdirectories of @dir, which has been created as
 * the NTFS inode @dir_ni.  */
static int
ntfs_3g_create_dirs_recursive(ntfs_inode *dir_ni, struct wim_dentry *dir,
                              struct ntfs_3g_apply_ctx *ctx)
{
        struct wim_dentry *child;

        for_dentry_child(child, dir) {
                ntfs_inode *ni;
                int ret;

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

                ni = ntfs_create(dir_ni, 0, child->d_extraction_name,
                                 child->d_extraction_name_nchars, S_IFDIR);
                if (!ni) {
                        ERROR_WITH_ERRNO("Error creating \"%s\" in NTFS volume",
                                         dentry_full_path(child));
                        return WIMLIB_ERR_NTFS_3G;
                }

                child->d_inode->i_mft_no = ni->mft_no;

                ret = report_file_created(&ctx->common);
                if (!ret)
                        ret = ntfs_3g_set_metadata(ni, child->d_inode, ctx);
                if (!ret)
                        ret = ntfs_3g_create_any_empty_ads(ni, child->d_inode, ctx);
                if (!ret)
                        ret = ntfs_3g_create_dirs_recursive(ni, child, ctx);

                if (ntfs_inode_close_in_dir(ni, dir_ni) && !ret) {
                        ERROR_WITH_ERRNO("Error closing \"%s\" in NTFS volume",
                                         dentry_full_path(child));
                        ret = WIMLIB_ERR_NTFS_3G;
                }
                if (ret)
                        return ret;
        }
        return 0;
}

/* For each WIM dentry in the @root tree that represents a directory, create the
 * corresponding directory in the NTFS volume @ctx->vol.  */
static int
ntfs_3g_create_directories(struct wim_dentry *root,
                           struct list_head *dentry_list,
                           struct ntfs_3g_apply_ctx *ctx)
{
        ntfs_inode *root_ni;
        int ret;
        struct wim_dentry *dentry;

        /* Create the directories using POSIX names.  */

        root_ni = ntfs_inode_open(ctx->vol, FILE_root);
        if (!root_ni) {
                ERROR_WITH_ERRNO("Can't open root of NTFS volume");
                return WIMLIB_ERR_NTFS_3G;
        }

        root->d_inode->i_mft_no = FILE_root;

        ret = ntfs_3g_create_dirs_recursive(root_ni, root, ctx);

        if (ntfs_inode_close(root_ni) && !ret) {
                ERROR_WITH_ERRNO("Error closing root of NTFS volume");
                ret = WIMLIB_ERR_NTFS_3G;
        }
        if (ret)
                return ret;

        /* Set the DOS name of any directory that has one.  */
        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
                if (!(dentry->d_inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY))
                        continue;
                if (!dentry_has_short_name(dentry))
                        continue;
                ret = ntfs_3g_restore_dos_name(NULL, NULL, dentry, ctx->vol);
                if (ret)
                        return ret;
                ret = report_file_created(&ctx->common);
                if (ret)
                        return ret;
        }
        return 0;
}

/* When creating an inode that will have a short (DOS) name, we create it using
 * the long name associated with the short name.  This ensures that the short
 * name gets associated with the correct long name.  */
static struct wim_dentry *
ntfs_3g_first_extraction_alias(struct wim_inode *inode)
{
        struct list_head *next = inode->i_extraction_aliases.next;
        struct wim_dentry *dentry;

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

/*
 * Add a hard link for the NTFS inode @ni at the location corresponding to the
 * WIM dentry @dentry.
 *
 * The parent directory must have already been created on the NTFS volume.
 *
 * Returns 0 on success; returns WIMLIB_ERR_NTFS_3G and sets errno on failure.
 */
static int
ntfs_3g_add_link(ntfs_inode *ni, struct wim_dentry *dentry)
{
        ntfs_inode *dir_ni;
        int res;

        /* Open the inode of the parent directory.  */
        dir_ni = ntfs_inode_open(ni->vol, dentry->d_parent->d_inode->i_mft_no);
        if (!dir_ni)
                goto fail;

        /* Create the link.  */
        res = ntfs_link(ni, dir_ni, dentry->d_extraction_name,
                        dentry->d_extraction_name_nchars);

        /* Close the parent directory.  */
        if (ntfs_inode_close(dir_ni) || res)
                goto fail;

        return 0;

fail:
        ERROR_WITH_ERRNO("Can't create link \"%s\" in NTFS volume",
                         dentry_full_path(dentry));
        return WIMLIB_ERR_NTFS_3G;
}

static int
ntfs_3g_create_nondirectory(struct wim_inode *inode,
                            const struct ntfs_3g_apply_ctx *ctx)
{
        struct wim_dentry *first_dentry;
        ntfs_inode *dir_ni;
        ntfs_inode *ni;
        struct list_head *next;
        struct wim_dentry *dentry;
        int ret;

        first_dentry = ntfs_3g_first_extraction_alias(inode);

        /* Create first link.  */

        dir_ni = ntfs_inode_open(ctx->vol, first_dentry->d_parent->d_inode->i_mft_no);
        if (!dir_ni) {
                ERROR_WITH_ERRNO("Can't open \"%s\" in NTFS volume",
                                 dentry_full_path(first_dentry->d_parent));
                return WIMLIB_ERR_NTFS_3G;
        }

        ni = ntfs_create(dir_ni, 0, first_dentry->d_extraction_name,
                         first_dentry->d_extraction_name_nchars, S_IFREG);

        if (!ni) {
                ERROR_WITH_ERRNO("Can't create \"%s\" in NTFS volume",
                                 dentry_full_path(first_dentry));
                ntfs_inode_close(dir_ni);
                return WIMLIB_ERR_NTFS_3G;
        }

        inode->i_mft_no = ni->mft_no;

        /* Set short name if present.  */
        if (dentry_has_short_name(first_dentry)) {

                ret = ntfs_3g_restore_dos_name(ni, dir_ni, first_dentry, ctx->vol);

                /* ntfs_3g_restore_dos_name() closed both 'ni' and 'dir_ni'.  */

                if (ret)
                        return ret;

                /* Reopen the inode.  */
                ni = ntfs_inode_open(ctx->vol, inode->i_mft_no);
                if (!ni) {
                        ERROR_WITH_ERRNO("Failed to reopen \"%s\" "
                                         "in NTFS volume",
                                         dentry_full_path(first_dentry));
                        return WIMLIB_ERR_NTFS_3G;
                }
        } else {
                /* Close the directory in which the first link was created.  */
                if (ntfs_inode_close(dir_ni)) {
                        ERROR_WITH_ERRNO("Failed to close \"%s\" in NTFS volume",
                                         dentry_full_path(first_dentry->d_parent));
                        ret = WIMLIB_ERR_NTFS_3G;
                        goto out_close_ni;
                }
        }

        /* Create additional links if present.  */
        next = inode->i_extraction_aliases.next;
        do {
                dentry = list_entry(next, struct wim_dentry,
                                    d_extraction_alias_node);
                if (dentry != first_dentry) {
                        ret = ntfs_3g_add_link(ni, dentry);
                        if (ret)
                                goto out_close_ni;
                }
                next = next->next;
        } while (next != &inode->i_extraction_aliases);

        /* Set metadata.  */
        ret = ntfs_3g_set_metadata(ni, inode, ctx);
        if (ret)
                goto out_close_ni;

        ret = ntfs_3g_create_any_empty_ads(ni, inode, ctx);

out_close_ni:
        /* Close the inode.  */
        if (ntfs_inode_close(ni) && !ret) {
                ERROR_WITH_ERRNO("Error closing \"%s\" in NTFS volume",
                                 dentry_full_path(first_dentry));
                ret = WIMLIB_ERR_NTFS_3G;
        }
        return ret;
}

/* For each WIM dentry in the @dentry_list that represents a nondirectory file,
 * create the corresponding nondirectory file in the NTFS volume.
 *
 * Directories must have already been created.  */
static int
ntfs_3g_create_nondirectories(struct list_head *dentry_list,
                              struct ntfs_3g_apply_ctx *ctx)
{
        struct wim_dentry *dentry;
        struct wim_inode *inode;
        int ret;

        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
                inode = dentry->d_inode;
                if (inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY)
                        continue;
                if (dentry == inode_first_extraction_dentry(inode)) {
                        ret = ntfs_3g_create_nondirectory(inode, ctx);
                        if (ret)
                                return ret;
                }
                ret = report_file_created(&ctx->common);
                if (ret)
                        return ret;
        }
        return 0;
}

static int
ntfs_3g_begin_extract_stream_to_attr(struct wim_lookup_table_entry *stream,
                                     ntfs_inode *ni,
                                     struct wim_inode *inode,
                                     ntfschar *stream_name,
                                     struct ntfs_3g_apply_ctx *ctx)
{
        struct wim_dentry *one_dentry = inode_first_extraction_dentry(inode);
        size_t stream_name_nchars = 0;
        ntfs_attr *attr;

        if (stream_name)
                for (const ntfschar *p = stream_name; *p; p++)
                        stream_name_nchars++;

        if (stream_name_nchars == 0)
                stream_name = AT_UNNAMED;
        if ((inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT)
            && (stream_name_nchars == 0))
        {
                if (stream->size > REPARSE_DATA_MAX_SIZE) {
                        ERROR("Reparse data of \"%s\" has size "
                              "%"PRIu64" bytes (exceeds %u bytes)",
                              dentry_full_path(one_dentry),
                              stream->size, REPARSE_DATA_MAX_SIZE);
                        return WIMLIB_ERR_INVALID_REPARSE_DATA;
                }
                ctx->reparse_ptr = ctx->rpbuf.rpdata;
                ctx->rpbuf.rpdatalen = cpu_to_le16(stream->size);
                ctx->rpbuf.rpreserved = cpu_to_le16(0);
                ctx->ntfs_reparse_inodes[ctx->num_reparse_inodes] = ni;
                ctx->wim_reparse_inodes[ctx->num_reparse_inodes] = inode;
                ctx->num_reparse_inodes++;
                return 0;
        }

        if (stream_name_nchars &&
            (ntfs_attr_add(ni, AT_DATA, stream_name,
                           stream_name_nchars, NULL, 0)))
        {
                ERROR_WITH_ERRNO("Failed to create named data stream of \"%s\"",
                                 dentry_full_path(one_dentry));
                return WIMLIB_ERR_NTFS_3G;
        }

        /* This should be ensured by extract_stream_list()  */
        wimlib_assert(ctx->num_open_attrs < MAX_OPEN_STREAMS);

        attr = ntfs_attr_open(ni, AT_DATA, stream_name, stream_name_nchars);
        if (!attr) {
                ERROR_WITH_ERRNO("Failed to open data stream of \"%s\"",
                                 dentry_full_path(one_dentry));
                return WIMLIB_ERR_NTFS_3G;
        }
        ctx->open_attrs[ctx->num_open_attrs++] = attr;
        ntfs_attr_truncate_solid(attr, stream->size);
        return 0;
}

static int
ntfs_3g_cleanup_stream_extract(struct ntfs_3g_apply_ctx *ctx)
{
        int ret = 0;

        for (unsigned i = 0; i < ctx->num_open_attrs; i++) {
                if (ntfs_attr_pclose(ctx->open_attrs[i]))
                        ret = -1;
                ntfs_attr_close(ctx->open_attrs[i]);
        }

        ctx->num_open_attrs = 0;

        for (unsigned i = 0; i < ctx->num_open_inodes; i++) {
                if (ntfs_inode_close(ctx->open_inodes[i]))
                        ret = -1;
        }
        ctx->num_open_inodes = 0;

        ctx->offset = 0;
        ctx->reparse_ptr = NULL;
        ctx->num_reparse_inodes = 0;
        return ret;
}

static ntfs_inode *
ntfs_3g_open_inode(struct wim_inode *inode, struct ntfs_3g_apply_ctx *ctx)
{
        ntfs_inode *ni = NULL;

        if (inode->i_visited) {
                for (u32 i = 0; i < ctx->num_open_inodes; i++) {
                        if (ctx->open_inodes[i]->mft_no == inode->i_mft_no) {
                                ni = ctx->open_inodes[i];
                                break;
                        }
                }
        }
        if (!ni) {
                ni = ntfs_inode_open(ctx->vol, inode->i_mft_no);
                ctx->open_inodes[ctx->num_open_inodes++] = ni;
                inode->i_visited = 1;
        }

        if (!ni) {
                ERROR_WITH_ERRNO("Can't open \"%s\" in NTFS volume",
                                 dentry_full_path(
                                        inode_first_extraction_dentry(inode)));
                return NULL;
        }
        return ni;
}

static int
ntfs_3g_begin_extract_stream(struct wim_lookup_table_entry *stream, void *_ctx)
{
        struct ntfs_3g_apply_ctx *ctx = _ctx;
        const struct stream_owner *owners = stream_owners(stream);
        int ret;

        for (u32 i = 0; i < stream->out_refcnt; i++) {
                struct wim_inode *inode = owners[i].inode;
                ntfschar *stream_name = (ntfschar *)owners[i].stream_name;
                ntfs_inode *ni;

                ret = WIMLIB_ERR_NTFS_3G;
                ni = ntfs_3g_open_inode(inode, ctx);
                if (!ni)
                        goto out_cleanup;

                ret = ntfs_3g_begin_extract_stream_to_attr(stream, ni, inode,
                                                           stream_name, ctx);
                if (ret)
                        goto out_cleanup;
        }
        ret = 0;
        goto out;

out_cleanup:
        ntfs_3g_cleanup_stream_extract(ctx);
out:
        for (u32 i = 0; i < stream->out_refcnt; i++)
                owners[i].inode->i_visited = 0;
        return ret;
}

static int
ntfs_3g_extract_chunk(const void *chunk, size_t size, void *_ctx)
{
        struct ntfs_3g_apply_ctx *ctx = _ctx;
        s64 res;

        for (unsigned i = 0; i < ctx->num_open_attrs; i++) {
                res = ntfs_attr_pwrite(ctx->open_attrs[i],
                                       ctx->offset, size, chunk);
                if (res != size) {
                        ERROR_WITH_ERRNO("Error writing data to NTFS volume");
                        return WIMLIB_ERR_NTFS_3G;
                }
        }
        if (ctx->reparse_ptr)
                ctx->reparse_ptr = mempcpy(ctx->reparse_ptr, chunk, size);
        ctx->offset += size;
        return 0;
}

static int
ntfs_3g_end_extract_stream(struct wim_lookup_table_entry *stream,
                           int status, void *_ctx)
{
        struct ntfs_3g_apply_ctx *ctx = _ctx;
        int ret;

        if (status) {
                ret = status;
                goto out;
        }

        for (u32 i = 0; i < ctx->num_reparse_inodes; i++) {
                struct wim_inode *inode = ctx->wim_reparse_inodes[i];

                ctx->rpbuf.rptag = cpu_to_le32(inode->i_reparse_tag);

                if (ntfs_set_ntfs_reparse_data(ctx->ntfs_reparse_inodes[i],
                                               (const char *)&ctx->rpbuf,
                                               stream->size + REPARSE_DATA_OFFSET,
                                               0))
                {
                        ERROR_WITH_ERRNO("Failed to set reparse "
                                         "data on \"%s\"",
                                         dentry_full_path(
                                                inode_first_extraction_dentry(inode)));
                        ret = WIMLIB_ERR_NTFS_3G;
                        goto out;
                }
        }
        ret = 0;
out:
        if (ntfs_3g_cleanup_stream_extract(ctx) && !ret) {
                ERROR_WITH_ERRNO("Error writing data to NTFS volume");
                ret = WIMLIB_ERR_NTFS_3G;
        }
        return ret;
}

static uint64_t
ntfs_3g_count_dentries(const struct list_head *dentry_list)
{
        const struct wim_dentry *dentry;
        uint64_t count = 0;

        list_for_each_entry(dentry, dentry_list, d_extraction_list_node) {
                count++;
                if ((dentry->d_inode->i_attributes & FILE_ATTRIBUTE_DIRECTORY) &&
                    dentry_has_short_name(dentry))
                {
                        count++;
                }

        }

        return count;
}

static int
ntfs_3g_extract(struct list_head *dentry_list, struct apply_ctx *_ctx)
{
        struct ntfs_3g_apply_ctx *ctx = (struct ntfs_3g_apply_ctx *)_ctx;
        ntfs_volume *vol;
        struct wim_dentry *root;
        int ret;

        /* For NTFS-3g extraction mode we require that the dentries to extract
         * form a single tree.  */
        root = list_first_entry(dentry_list, struct wim_dentry,
                                d_extraction_list_node);

        /* Mount the NTFS volume.  */
        vol = ntfs_mount(ctx->common.target, 0);
        if (!vol) {
                ERROR_WITH_ERRNO("Failed to mount \"%s\" with NTFS-3g",
                                 ctx->common.target);
                return WIMLIB_ERR_NTFS_3G;
        }
        ctx->vol = vol;

        /* Create all inodes and aliases, including short names, and set
         * metadata (attributes, security descriptors, and timestamps).  */

        ret = start_file_structure_phase(&ctx->common,
                                         ntfs_3g_count_dentries(dentry_list));
        if (ret)
                goto out_unmount;

        ret = ntfs_3g_create_directories(root, dentry_list, ctx);
        if (ret)
                goto out_unmount;

        ret = ntfs_3g_create_nondirectories(dentry_list, ctx);
        if (ret)
                goto out_unmount;

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

        /* Extract streams.  */
        struct read_stream_list_callbacks cbs = {
                .begin_stream      = ntfs_3g_begin_extract_stream,
                .begin_stream_ctx  = ctx,
                .consume_chunk     = ntfs_3g_extract_chunk,
                .consume_chunk_ctx = ctx,
                .end_stream        = ntfs_3g_end_extract_stream,
                .end_stream_ctx    = ctx,
        };
        ret = extract_stream_list(&ctx->common, &cbs);

        /* We do not need a final pass to set timestamps because libntfs-3g does
         * not update timestamps automatically (exception:
         * ntfs_set_ntfs_dos_name() does, but we handle this elsewhere).  */

out_unmount:
        if (ntfs_umount(ctx->vol, FALSE) && !ret) {
                ERROR_WITH_ERRNO("Failed to unmount \"%s\" with NTFS-3g",
                                 ctx->common.target);
                ret = WIMLIB_ERR_NTFS_3G;
        }
        return ret;
}

const struct apply_operations ntfs_3g_apply_ops = {
        .name                   = "NTFS-3g",
        .get_supported_features = ntfs_3g_get_supported_features,
        .extract                = ntfs_3g_extract,
        .context_size           = sizeof(struct ntfs_3g_apply_ctx),
        .single_tree_only       = true,
};

void
libntfs3g_global_init(void)
{
       ntfs_set_char_encoding(setlocale(LC_ALL, ""));
}