/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2020 Oleksandr Tymoshenko <gonzo@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#include <sys/errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "endian.h"
#include "image.h"
#include "format.h"
#include "mkimg.h"

#define PAYLOAD_BLOCK_SIZE      (16*1024*1024)
#define SIZE_64KB               (64*1024)
#define SIZE_1MB                (1024*1024)

#define META_IS_REQUIRED        (1 << 2)
#define META_IS_VIRTUAL_DISK    (1 << 1)

#define PAYLOAD_BLOCK_FULLY_PRESENT     6
#define SB_BLOCK_NOT_PRESENT            0
#define BAT_ENTRY(offset, flags)        (((offset) << 20) | (flags))

/* Regions' UUIDs */
#define VHDX_REGION_BAT_GUID    \
        {0x2dc27766,0xf623,0x4200,0x9d,0x64,{0x11,0x5e,0x9b,0xfd,0x4a,0x08}}
#define VHDX_REGION_METADATA_GUID       \
        {0x8b7ca206,0x4790,0x4b9a,0xb8,0xfe,{0x57,0x5f,0x05,0x0f,0x88,0x6e}}
static mkimg_uuid_t vhdx_bat_guid = VHDX_REGION_BAT_GUID;
static mkimg_uuid_t vhdx_metadata_guid = VHDX_REGION_METADATA_GUID;

/* Metadata UUIDs */
#define VHDX_META_FILE_PARAMETERS       \
        {0xcaa16737,0xfa36,0x4d43,0xb3,0xb6,{0x33,0xf0,0xaa,0x44,0xe7,0x6b}}
#define VHDX_META_VDISK_SIZE    \
        {0x2fa54224,0xcd1b,0x4876,0xb2,0x11,{0x5d,0xbe,0xd8,0x3b,0xf4,0xb8}}
#define VHDX_META_VDISK_ID      \
        {0xbeca12ab,0xb2e6,0x4523,0x93,0xef,{0xc3,0x09,0xe0,0x00,0xc7,0x46}}
#define VHDX_META_LOGICAL_SSIZE \
        {0x8141bf1D,0xa96f,0x4709,0xba,0x47,{0xf2,0x33,0xa8,0xfa,0xab,0x5f}}
#define VHDX_META_PHYS_SSIZE    \
        {0xcda348c7,0x445d,0x4471,0x9c,0xc9,{0xe9,0x88,0x52,0x51,0xc5,0x56}}

static mkimg_uuid_t vhdx_meta_file_parameters_guid = VHDX_META_FILE_PARAMETERS;
static mkimg_uuid_t vhdx_meta_vdisk_size_guid = VHDX_META_VDISK_SIZE;
static mkimg_uuid_t vhdx_meta_vdisk_id_guid = VHDX_META_VDISK_ID;
static mkimg_uuid_t vhdx_meta_logical_ssize_guid = VHDX_META_LOGICAL_SSIZE;
static mkimg_uuid_t vhdx_meta_phys_ssize_guid = VHDX_META_PHYS_SSIZE;

struct vhdx_filetype_identifier {
        uint64_t        signature;
#define VHDX_FILETYPE_ID_SIGNATURE      0x656C696678646876
        uint8_t         creator[512];
};

struct vhdx_header {
        uint32_t        signature;
#define VHDX_HEADER_SIGNATURE           0x64616568
        uint32_t        checksum;
        uint64_t        sequence_number;
        mkimg_uuid_t    file_write_guid;
        mkimg_uuid_t    data_write_guid;
        mkimg_uuid_t    log_guid;
        uint16_t        log_version;
        uint16_t        version;
        uint32_t        log_length;
        uint64_t        log_offset;
        uint8_t         _reserved[4016];
};

struct vhdx_region_table_header {
        uint32_t        signature;
#define VHDX_REGION_TABLE_HEADER_SIGNATURE      0x69676572
        uint32_t        checksum;
        uint32_t        entry_count;
        uint32_t        _reserved;
};

struct vhdx_region_table_entry {
        mkimg_uuid_t    guid;
        uint64_t        file_offset;
        uint32_t        length;
        uint32_t        required;
};

struct vhdx_metadata_table_header {
        uint64_t        signature;
#define VHDX_METADATA_TABLE_HEADER_SIGNATURE            0x617461646174656D
        uint16_t        _reserved;
        uint16_t        entry_count;
        uint8_t         _reserved2[20];
};

struct vhdx_metadata_table_entry {
        mkimg_uuid_t    item_id;
        uint32_t        offset;
        uint32_t        length;
        uint32_t        flags;
        uint32_t        _reserved;
};

#define CRC32C(c, d) (c = (c>>8) ^ crc_c[(c^(d))&0xFF])

static uint32_t crc_c[256] = {
        0x00000000, 0xF26B8303, 0xE13B70F7, 0x1350F3F4,
        0xC79A971F, 0x35F1141C, 0x26A1E7E8, 0xD4CA64EB,
        0x8AD958CF, 0x78B2DBCC, 0x6BE22838, 0x9989AB3B,
        0x4D43CFD0, 0xBF284CD3, 0xAC78BF27, 0x5E133C24,
        0x105EC76F, 0xE235446C, 0xF165B798, 0x030E349B,
        0xD7C45070, 0x25AFD373, 0x36FF2087, 0xC494A384,
        0x9A879FA0, 0x68EC1CA3, 0x7BBCEF57, 0x89D76C54,
        0x5D1D08BF, 0xAF768BBC, 0xBC267848, 0x4E4DFB4B,
        0x20BD8EDE, 0xD2D60DDD, 0xC186FE29, 0x33ED7D2A,
        0xE72719C1, 0x154C9AC2, 0x061C6936, 0xF477EA35,
        0xAA64D611, 0x580F5512, 0x4B5FA6E6, 0xB93425E5,
        0x6DFE410E, 0x9F95C20D, 0x8CC531F9, 0x7EAEB2FA,
        0x30E349B1, 0xC288CAB2, 0xD1D83946, 0x23B3BA45,
        0xF779DEAE, 0x05125DAD, 0x1642AE59, 0xE4292D5A,
        0xBA3A117E, 0x4851927D, 0x5B016189, 0xA96AE28A,
        0x7DA08661, 0x8FCB0562, 0x9C9BF696, 0x6EF07595,
        0x417B1DBC, 0xB3109EBF, 0xA0406D4B, 0x522BEE48,
        0x86E18AA3, 0x748A09A0, 0x67DAFA54, 0x95B17957,
        0xCBA24573, 0x39C9C670, 0x2A993584, 0xD8F2B687,
        0x0C38D26C, 0xFE53516F, 0xED03A29B, 0x1F682198,
        0x5125DAD3, 0xA34E59D0, 0xB01EAA24, 0x42752927,
        0x96BF4DCC, 0x64D4CECF, 0x77843D3B, 0x85EFBE38,
        0xDBFC821C, 0x2997011F, 0x3AC7F2EB, 0xC8AC71E8,
        0x1C661503, 0xEE0D9600, 0xFD5D65F4, 0x0F36E6F7,
        0x61C69362, 0x93AD1061, 0x80FDE395, 0x72966096,
        0xA65C047D, 0x5437877E, 0x4767748A, 0xB50CF789,
        0xEB1FCBAD, 0x197448AE, 0x0A24BB5A, 0xF84F3859,
        0x2C855CB2, 0xDEEEDFB1, 0xCDBE2C45, 0x3FD5AF46,
        0x7198540D, 0x83F3D70E, 0x90A324FA, 0x62C8A7F9,
        0xB602C312, 0x44694011, 0x5739B3E5, 0xA55230E6,
        0xFB410CC2, 0x092A8FC1, 0x1A7A7C35, 0xE811FF36,
        0x3CDB9BDD, 0xCEB018DE, 0xDDE0EB2A, 0x2F8B6829,
        0x82F63B78, 0x709DB87B, 0x63CD4B8F, 0x91A6C88C,
        0x456CAC67, 0xB7072F64, 0xA457DC90, 0x563C5F93,
        0x082F63B7, 0xFA44E0B4, 0xE9141340, 0x1B7F9043,
        0xCFB5F4A8, 0x3DDE77AB, 0x2E8E845F, 0xDCE5075C,
        0x92A8FC17, 0x60C37F14, 0x73938CE0, 0x81F80FE3,
        0x55326B08, 0xA759E80B, 0xB4091BFF, 0x466298FC,
        0x1871A4D8, 0xEA1A27DB, 0xF94AD42F, 0x0B21572C,
        0xDFEB33C7, 0x2D80B0C4, 0x3ED04330, 0xCCBBC033,
        0xA24BB5A6, 0x502036A5, 0x4370C551, 0xB11B4652,
        0x65D122B9, 0x97BAA1BA, 0x84EA524E, 0x7681D14D,
        0x2892ED69, 0xDAF96E6A, 0xC9A99D9E, 0x3BC21E9D,
        0xEF087A76, 0x1D63F975, 0x0E330A81, 0xFC588982,
        0xB21572C9, 0x407EF1CA, 0x532E023E, 0xA145813D,
        0x758FE5D6, 0x87E466D5, 0x94B49521, 0x66DF1622,
        0x38CC2A06, 0xCAA7A905, 0xD9F75AF1, 0x2B9CD9F2,
        0xFF56BD19, 0x0D3D3E1A, 0x1E6DCDEE, 0xEC064EED,
        0xC38D26C4, 0x31E6A5C7, 0x22B65633, 0xD0DDD530,
        0x0417B1DB, 0xF67C32D8, 0xE52CC12C, 0x1747422F,
        0x49547E0B, 0xBB3FFD08, 0xA86F0EFC, 0x5A048DFF,
        0x8ECEE914, 0x7CA56A17, 0x6FF599E3, 0x9D9E1AE0,
        0xD3D3E1AB, 0x21B862A8, 0x32E8915C, 0xC083125F,
        0x144976B4, 0xE622F5B7, 0xF5720643, 0x07198540,
        0x590AB964, 0xAB613A67, 0xB831C993, 0x4A5A4A90,
        0x9E902E7B, 0x6CFBAD78, 0x7FAB5E8C, 0x8DC0DD8F,
        0xE330A81A, 0x115B2B19, 0x020BD8ED, 0xF0605BEE,
        0x24AA3F05, 0xD6C1BC06, 0xC5914FF2, 0x37FACCF1,
        0x69E9F0D5, 0x9B8273D6, 0x88D28022, 0x7AB90321,
        0xAE7367CA, 0x5C18E4C9, 0x4F48173D, 0xBD23943E,
        0xF36E6F75, 0x0105EC76, 0x12551F82, 0xE03E9C81,
        0x34F4F86A, 0xC69F7B69, 0xD5CF889D, 0x27A40B9E,
        0x79B737BA, 0x8BDCB4B9, 0x988C474D, 0x6AE7C44E,
        0xBE2DA0A5, 0x4C4623A6, 0x5F16D052, 0xAD7D5351
};

static uint32_t
crc32c(const void *data, uint32_t len)
{
        uint32_t i, crc;
        const uint8_t *buf = (const uint8_t *)data;

        crc = ~0;
        for (i = 0; i < len; i++)
                CRC32C(crc, buf[i]);
        crc = ~crc;
        return crc;
}

static int
vhdx_resize(lba_t imgsz)
{
        uint64_t imagesz;

        imagesz = imgsz * secsz;
        imagesz = (imagesz + PAYLOAD_BLOCK_SIZE - 1) & ~(PAYLOAD_BLOCK_SIZE - 1);
        return (image_set_size(imagesz / secsz));
}

static int
vhdx_write_and_pad(int fd, const void *data, size_t data_size, size_t align)
{
        size_t pad_size;

        if (sparse_write(fd, data, data_size) < 0)
                return (errno);

        if (data_size % align == 0)
                return (0);

        pad_size = align - (data_size % align);
        return  image_copyout_zeroes(fd, pad_size);
}

static int
vhdx_write_headers(int fd)
{
        int error;
        struct vhdx_header header;
        uint32_t checksum;

        /* Write header 1 */
        memset(&header, 0, sizeof(header));
        le32enc(&header.signature, VHDX_HEADER_SIGNATURE);
        le32enc(&header.sequence_number, 0);
        le16enc(&header.log_version, 0);
        le16enc(&header.version, 1);
        le32enc(&header.log_length, SIZE_1MB);
        le64enc(&header.log_offset, SIZE_1MB);
        checksum = crc32c(&header, sizeof(header));
        le32enc(&header.checksum, checksum);
        error = vhdx_write_and_pad(fd, &header, sizeof(header), SIZE_64KB);
        if (error)
                return (error);

        /* Write header 2, and make it active */
        le32enc(&header.sequence_number, 1);
        header.checksum = 0;
        checksum = crc32c(&header, sizeof(header));
        le32enc(&header.checksum, checksum);
        return vhdx_write_and_pad(fd, &header, sizeof(header), SIZE_64KB);
}

static int
vhdx_write_region_tables(int fd)
{
        int error;
        uint8_t *region_table;
        struct vhdx_region_table_header header;
        struct vhdx_region_table_entry entry;
        uint32_t checksum;

        region_table = malloc(SIZE_64KB);
        if (region_table == NULL)
                return errno;
        memset(region_table, 0, SIZE_64KB);

        memset(&header, 0, sizeof(header));
        le32enc(&header.signature, VHDX_REGION_TABLE_HEADER_SIGNATURE);
        le32enc(&header.entry_count, 2);
        memcpy(region_table, &header, sizeof(header));

        /* Metadata region entry */
        mkimg_uuid_enc(&entry.guid, &vhdx_metadata_guid);
        le64enc(&entry.file_offset, 2*SIZE_1MB);
        le64enc(&entry.length, SIZE_1MB);
        memcpy(region_table + sizeof(header),
            &entry, sizeof(entry));

        /* BAT region entry */
        mkimg_uuid_enc(&entry.guid, &vhdx_bat_guid);
        le64enc(&entry.file_offset, 3*SIZE_1MB);
        le64enc(&entry.length, SIZE_1MB);
        memcpy(region_table + sizeof(header) + sizeof(entry),
            &entry, sizeof(entry));

        checksum = crc32c(region_table, SIZE_64KB);
        le32enc(region_table + 4, checksum);

        /* Region Table 1 */
        if (sparse_write(fd, region_table, SIZE_64KB) < 0) {
                error = errno;
                free(region_table);
                return error;
        }

        /* Region Table 2 */
        if (sparse_write(fd, region_table, SIZE_64KB) < 0) {
                error = errno;
                free(region_table);
                return error;
        }

        free(region_table);
        return (0);
}

static int
vhdx_write_metadata(int fd, uint64_t image_size)
{
        int error;
        uint8_t *metadata;
        struct vhdx_metadata_table_header header;
        struct vhdx_metadata_table_entry entry;
        int header_ptr, data_ptr;
        mkimg_uuid_t id;

        metadata = malloc(SIZE_1MB);
        if (metadata == NULL)
                return errno;
        memset(metadata, 0, SIZE_1MB);

        memset(&header, 0, sizeof(header));
        memset(&entry, 0, sizeof(entry));

        le64enc(&header.signature, VHDX_METADATA_TABLE_HEADER_SIGNATURE);
        le16enc(&header.entry_count, 5);
        memcpy(metadata, &header, sizeof(header));
        header_ptr = sizeof(header);
        data_ptr = SIZE_64KB;

        /* File parameters */
        mkimg_uuid_enc(&entry.item_id, &vhdx_meta_file_parameters_guid);
        le32enc(&entry.offset, data_ptr);
        le32enc(&entry.length, 8);
        le32enc(&entry.flags, META_IS_REQUIRED);
        memcpy(metadata + header_ptr, &entry, sizeof(entry));
        header_ptr += sizeof(entry);
        le32enc(metadata + data_ptr, PAYLOAD_BLOCK_SIZE);
        data_ptr += 4;
        le32enc(metadata + data_ptr, 0);
        data_ptr += 4;

        /* Virtual Disk Size */
        mkimg_uuid_enc(&entry.item_id, &vhdx_meta_vdisk_size_guid);
        le32enc(&entry.offset, data_ptr);
        le32enc(&entry.length, 8);
        le32enc(&entry.flags, META_IS_REQUIRED | META_IS_VIRTUAL_DISK);
        memcpy(metadata + header_ptr, &entry, sizeof(entry));
        header_ptr += sizeof(entry);
        le64enc(metadata + data_ptr, image_size);
        data_ptr += 8;

        /* Virtual Disk ID */
        mkimg_uuid_enc(&entry.item_id, &vhdx_meta_vdisk_id_guid);
        le32enc(&entry.offset, data_ptr);
        le32enc(&entry.length, 16);
        le32enc(&entry.flags, META_IS_REQUIRED | META_IS_VIRTUAL_DISK);
        memcpy(metadata + header_ptr, &entry, sizeof(entry));
        header_ptr += sizeof(entry);
        mkimg_uuid(&id);
        mkimg_uuid_enc(metadata + data_ptr, &id);
        data_ptr += 16;

        /* Logical Sector Size*/
        mkimg_uuid_enc(&entry.item_id, &vhdx_meta_logical_ssize_guid);
        le32enc(&entry.offset, data_ptr);
        le32enc(&entry.length, 4);
        le32enc(&entry.flags, META_IS_REQUIRED | META_IS_VIRTUAL_DISK);
        memcpy(metadata + header_ptr, &entry, sizeof(entry));
        header_ptr += sizeof(entry);
        le32enc(metadata + data_ptr, secsz);
        data_ptr += 4;

        /* Physical Sector Size*/
        mkimg_uuid_enc(&entry.item_id, &vhdx_meta_phys_ssize_guid);
        le32enc(&entry.offset, data_ptr);
        le32enc(&entry.length, 4);
        le32enc(&entry.flags, META_IS_REQUIRED | META_IS_VIRTUAL_DISK);
        memcpy(metadata + header_ptr, &entry, sizeof(entry));
        header_ptr += sizeof(entry);
        le32enc(metadata + data_ptr, blksz);
        data_ptr += 4;

        if (sparse_write(fd, metadata, SIZE_1MB) < 0) {
                error = errno;
                free(metadata);
                return error;
        }

        free(metadata);
        return (0);
}

static int
vhdx_write_bat(int fd, uint64_t image_size)
{
        int error;
        uint8_t *bat;
        int chunk_ratio;
        uint64_t bat_size, data_block_count, total_bat_entries;
        uint64_t idx, payload_offset, bat_ptr;

        bat = malloc(SIZE_1MB);
        if (bat == NULL)
                return errno;
        memset(bat, 0, SIZE_1MB);

        chunk_ratio = ((1024*1024*8ULL) * secsz) / PAYLOAD_BLOCK_SIZE;
        data_block_count = (image_size + PAYLOAD_BLOCK_SIZE - 1) / PAYLOAD_BLOCK_SIZE;
        total_bat_entries = data_block_count + (data_block_count - 1)/chunk_ratio;
        bat_size = total_bat_entries * 8;
        /* round it up to 1Mb */
        bat_size = (bat_size + SIZE_1MB - 1) & ~(SIZE_1MB - 1);

        /*
         * Offset to the first payload block
         * 1Mb of header + 1Mb of log + 1Mb of metadata + XMb BAT
         */
        payload_offset = 3 + (bat_size / SIZE_1MB);
        bat_ptr = 0;
        for (idx = 0; idx < data_block_count; idx++) {
                le64enc(bat + bat_ptr,
                    BAT_ENTRY(payload_offset, PAYLOAD_BLOCK_FULLY_PRESENT));
                bat_ptr += 8;
                payload_offset += (PAYLOAD_BLOCK_SIZE / SIZE_1MB);

                /* Flush the BAT buffer if required */
                if (bat_ptr == SIZE_1MB) {
                        if (sparse_write(fd, bat, SIZE_1MB) < 0) {
                                error = errno;
                                free(bat);
                                return error;
                        }
                        memset(bat, 0, SIZE_1MB);
                        bat_ptr = 0;
                }

                if (((idx + 1) % chunk_ratio) == 0 &&
                    (idx != data_block_count - 1)) {
                        le64enc(bat + bat_ptr,
                            BAT_ENTRY(0, SB_BLOCK_NOT_PRESENT));
                        bat_ptr += 8;

                        /* Flush the BAT buffer if required */
                        if (bat_ptr == SIZE_1MB) {
                                if (sparse_write(fd, bat, SIZE_1MB) < 0) {
                                        error = errno;
                                        free(bat);
                                        return error;
                                }
                                memset(bat, 0, SIZE_1MB);
                                bat_ptr = 0;
                        }
                }
        }

        if (bat_ptr != 0) {
                if (sparse_write(fd, bat, SIZE_1MB) < 0) {
                        error = errno;
                        free(bat);
                        return error;
                }
        }

        free(bat);
        return (0);
}

static int
vhdx_write(int fd)
{
        int error;
        uint64_t imgsz, rawsz;
        struct vhdx_filetype_identifier identifier;

        rawsz = image_get_size() * secsz;
        imgsz = (rawsz + PAYLOAD_BLOCK_SIZE - 1) & ~(PAYLOAD_BLOCK_SIZE - 1);

        memset(&identifier, 0, sizeof(identifier));
        le64enc(&identifier.signature, VHDX_FILETYPE_ID_SIGNATURE);
        error = vhdx_write_and_pad(fd, &identifier, sizeof(identifier), SIZE_64KB);
        if (error)
                return (error);

        error = vhdx_write_headers(fd);
        if (error)
                return (error);


        error = vhdx_write_region_tables(fd);
        if (error)
                return (error);

        /* Reserved area */
        error = image_copyout_zeroes(fd, SIZE_1MB - 5*SIZE_64KB);

        /* Log */
        error = image_copyout_zeroes(fd, SIZE_1MB);
        if (error)
                return (error);

        error = vhdx_write_metadata(fd, imgsz);
        if (error)
                return (error);

        error = vhdx_write_bat(fd, imgsz);
        if (error)
                return (error);

        error = image_copyout(fd);
        if (error)
                return (error);

        return (0);
}

static struct mkimg_format vhdx_format = {
        .name = "vhdx",
        .description = "Virtual Hard Disk, version 2",
        .resize = vhdx_resize,
        .write = vhdx_write,
};

FORMAT_DEFINE(vhdx_format);