Archipelago » qemu

/*

 * Block driver for Parallels disk image format

 *

 * Copyright (c) 2007 Alex Beregszaszi

 *

 * This code is based on comparing different disk images created by Parallels.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "qemu-common.h"

#include "block/block_int.h"

#include "qemu/module.h"

/**************************************************************/

#define HEADER_MAGIC "WithoutFreeSpace"

#define HEADER_VERSION 2

#define HEADER_SIZE 64

// always little-endian

struct parallels_header {

    char magic[16]; // "WithoutFreeSpace"

    uint32_t version;

    uint32_t heads;

    uint32_t cylinders;

    uint32_t tracks;

    uint32_t catalog_entries;

    uint32_t nb_sectors;

    char padding[24];

} QEMU_PACKED;

typedef struct BDRVParallelsState {

    CoMutex lock;

    uint32_t *catalog_bitmap;

    int catalog_size;

    int tracks;

} BDRVParallelsState;

static int parallels_probe(const uint8_t *buf, int buf_size, const char *filename)

{

    const struct parallels_header *ph = (const void *)buf;

    if (buf_size < HEADER_SIZE)

        return 0;

    if (!memcmp(ph->magic, HEADER_MAGIC, 16) &&

        (le32_to_cpu(ph->version) == HEADER_VERSION))

        return 100;

    return 0;

}

static int parallels_open(BlockDriverState *bs, int flags)

{

    BDRVParallelsState *s = bs->opaque;

    int i;

    struct parallels_header ph;

    bs->read_only = 1; // no write support yet

    if (bdrv_pread(bs->file, 0, &ph, sizeof(ph)) != sizeof(ph))

        goto fail;

    if (memcmp(ph.magic, HEADER_MAGIC, 16) ||

        (le32_to_cpu(ph.version) != HEADER_VERSION)) {

        goto fail;

    }

    bs->total_sectors = le32_to_cpu(ph.nb_sectors);

    s->tracks = le32_to_cpu(ph.tracks);

    s->catalog_size = le32_to_cpu(ph.catalog_entries);

    s->catalog_bitmap = g_malloc(s->catalog_size * 4);

    if (bdrv_pread(bs->file, 64, s->catalog_bitmap, s->catalog_size * 4) !=

        s->catalog_size * 4)

        goto fail;

    for (i = 0; i < s->catalog_size; i++)

        le32_to_cpus(&s->catalog_bitmap[i]);

    qemu_co_mutex_init(&s->lock);

    return 0;

fail:

    if (s->catalog_bitmap)

        g_free(s->catalog_bitmap);

    return -1;

}

static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)

{

    BDRVParallelsState *s = bs->opaque;

    uint32_t index, offset;

    index = sector_num / s->tracks;

    offset = sector_num % s->tracks;

    /* not allocated */

    if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))

        return -1;

    return (uint64_t)(s->catalog_bitmap[index] + offset) * 512;

}

static int parallels_read(BlockDriverState *bs, int64_t sector_num,

                    uint8_t *buf, int nb_sectors)

{

    while (nb_sectors > 0) {

        int64_t position = seek_to_sector(bs, sector_num);

        if (position >= 0) {

            if (bdrv_pread(bs->file, position, buf, 512) != 512)

                return -1;

        } else {

            memset(buf, 0, 512);

        }

        nb_sectors--;

        sector_num++;

        buf += 512;

    }

    return 0;

}

static coroutine_fn int parallels_co_read(BlockDriverState *bs, int64_t sector_num,

                                          uint8_t *buf, int nb_sectors)

{

    int ret;

    BDRVParallelsState *s = bs->opaque;

    qemu_co_mutex_lock(&s->lock);

    ret = parallels_read(bs, sector_num, buf, nb_sectors);

    qemu_co_mutex_unlock(&s->lock);

    return ret;

}

static void parallels_close(BlockDriverState *bs)

{

    BDRVParallelsState *s = bs->opaque;

    g_free(s->catalog_bitmap);

}

static BlockDriver bdrv_parallels = {

    .format_name        = "parallels",

    .instance_size        = sizeof(BDRVParallelsState),

    .bdrv_probe                = parallels_probe,

    .bdrv_open                = parallels_open,

    .bdrv_read          = parallels_co_read,

    .bdrv_close                = parallels_close,

};

static void bdrv_parallels_init(void)

{

    bdrv_register(&bdrv_parallels);

}

block_init(bdrv_parallels_init);