/*
 * volume_id - reads filesystem label and uuid
 *
 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
 *
 *      This library 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 2.1 of the License, or (at your option) any later version.
 *
 *      This library 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 library; if not, write to the Free Software
 *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "volume_id_internal.h"

struct ntfs_super_block {
        uint8_t         jump[3];
        uint8_t         oem_id[8];
        uint16_t        bytes_per_sector;
        uint8_t         sectors_per_cluster;
        uint16_t        reserved_sectors;
        uint8_t         fats;
        uint16_t        root_entries;
        uint16_t        sectors;
        uint8_t         media_type;
        uint16_t        sectors_per_fat;
        uint16_t        sectors_per_track;
        uint16_t        heads;
        uint32_t        hidden_sectors;
        uint32_t        large_sectors;
        uint16_t        unused[2];
        uint64_t        number_of_sectors;
        uint64_t        mft_cluster_location;
        uint64_t        mft_mirror_cluster_location;
        int8_t          cluster_per_mft_record;
        uint8_t         reserved1[3];
        int8_t          cluster_per_index_record;
        uint8_t         reserved2[3];
        uint8_t         volume_serial[8];
        uint16_t        checksum;
} PACKED;

struct master_file_table_record {
        uint8_t         magic[4];
        uint16_t        usa_ofs;
        uint16_t        usa_count;
        uint64_t        lsn;
        uint16_t        sequence_number;
        uint16_t        link_count;
        uint16_t        attrs_offset;
        uint16_t        flags;
        uint32_t        bytes_in_use;
        uint32_t        bytes_allocated;
} PACKED;

struct file_attribute {
        uint32_t        type;
        uint32_t        len;
        uint8_t         non_resident;
        uint8_t         name_len;
        uint16_t        name_offset;
        uint16_t        flags;
        uint16_t        instance;
        uint32_t        value_len;
        uint16_t        value_offset;
} PACKED;

struct volume_info {
        uint64_t        reserved;
        uint8_t         major_ver;
        uint8_t         minor_ver;
} PACKED;

#define MFT_RECORD_VOLUME                       3
#define MFT_RECORD_ATTR_VOLUME_NAME             0x60
#define MFT_RECORD_ATTR_VOLUME_INFO             0x70
#define MFT_RECORD_ATTR_OBJECT_ID               0x40
#define MFT_RECORD_ATTR_END                     0xffffffffu

int FAST_FUNC volume_id_probe_ntfs(struct volume_id *id /*,uint64_t off*/)
{
#define off ((uint64_t)0)
        unsigned sector_size;
        unsigned cluster_size;
        uint64_t mft_cluster;
        uint64_t mft_off;
        unsigned mft_record_size;
        unsigned attr_type;
        unsigned attr_off;
        unsigned attr_len;
        unsigned val_off;
        unsigned val_len;
        struct master_file_table_record *mftr;
        struct ntfs_super_block *ns;
        const uint8_t *buf;
        const uint8_t *val;

        dbg("probing at offset 0x%llx", (unsigned long long) off);

        ns = volume_id_get_buffer(id, off, 0x200);
        if (ns == NULL)
                return -1;

        if (memcmp(ns->oem_id, "NTFS", 4) != 0)
                return -1;

        volume_id_set_uuid(id, ns->volume_serial, UUID_NTFS);

        sector_size = le16_to_cpu(ns->bytes_per_sector);
        cluster_size = ns->sectors_per_cluster * sector_size;
        mft_cluster = le64_to_cpu(ns->mft_cluster_location);
        mft_off = mft_cluster * cluster_size;

        if (ns->cluster_per_mft_record < 0)
                /* size = -log2(mft_record_size); normally 1024 Bytes */
                mft_record_size = 1 << -ns->cluster_per_mft_record;
        else
                mft_record_size = ns->cluster_per_mft_record * cluster_size;

        dbg("sectorsize  0x%x", sector_size);
        dbg("clustersize 0x%x", cluster_size);
        dbg("mftcluster  %llu", (unsigned long long) mft_cluster);
        dbg("mftoffset  0x%llx", (unsigned long long) mft_off);
        dbg("cluster per mft_record  %i", ns->cluster_per_mft_record);
        dbg("mft record size  %i", mft_record_size);

        buf = volume_id_get_buffer(id, off + mft_off + (MFT_RECORD_VOLUME * mft_record_size),
                         mft_record_size);
        if (buf == NULL)
                goto found;

        mftr = (struct master_file_table_record*) buf;

        dbg("mftr->magic '%c%c%c%c'", mftr->magic[0], mftr->magic[1], mftr->magic[2], mftr->magic[3]);
        if (memcmp(mftr->magic, "FILE", 4) != 0)
                goto found;

        attr_off = le16_to_cpu(mftr->attrs_offset);
        dbg("file $Volume's attributes are at offset %i", attr_off);

        while (1) {
                struct file_attribute *attr;

                attr = (struct file_attribute*) &buf[attr_off];
                attr_type = le32_to_cpu(attr->type);
                attr_len = le16_to_cpu(attr->len);
                val_off = le16_to_cpu(attr->value_offset);
                val_len = le32_to_cpu(attr->value_len);
                attr_off += attr_len;

                if (attr_len == 0)
                        break;

                if (attr_off >= mft_record_size)
                        break;

                if (attr_type == MFT_RECORD_ATTR_END)
                        break;

                dbg("found attribute type 0x%x, len %i, at offset %i",
                    attr_type, attr_len, attr_off);

//              if (attr_type == MFT_RECORD_ATTR_VOLUME_INFO) {
//                      struct volume_info *info;
//                      dbg("found info, len %i", val_len);
//                      info = (struct volume_info*) (((uint8_t *) attr) + val_off);
//                      snprintf(id->type_version, sizeof(id->type_version)-1,
//                               "%u.%u", info->major_ver, info->minor_ver);
//              }

                if (attr_type == MFT_RECORD_ATTR_VOLUME_NAME) {
                        dbg("found label, len %i", val_len);
                        if (val_len > VOLUME_ID_LABEL_SIZE)
                                val_len = VOLUME_ID_LABEL_SIZE;

                        val = ((uint8_t *) attr) + val_off;
//                      volume_id_set_label_raw(id, val, val_len);
                        volume_id_set_label_unicode16(id, val, LE, val_len);
                }
        }

 found:
//      volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
//      id->type = "ntfs";

        return 0;
}