Archipelago » qemu

/*

 * Block driver for the VMDK format

 * 

 * Copyright (c) 2004 Fabrice Bellard

 * 

 * 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 "vl.h"

#include "block_int.h"

/* XXX: this code is untested */

/* XXX: add write support */

#define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')

#define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')

typedef struct {

    uint32_t version;

    uint32_t flags;

    uint32_t disk_sectors;

    uint32_t granularity;

    uint32_t l1dir_offset;

    uint32_t l1dir_size;

    uint32_t file_sectors;

    uint32_t cylinders;

    uint32_t heads;

    uint32_t sectors_per_track;

} VMDK3Header;

typedef struct {

    uint32_t version;

    uint32_t flags;

    int64_t capacity;

    int64_t granularity;

    int64_t desc_offset;

    int64_t desc_size;

    int32_t num_gtes_per_gte;

    int64_t rgd_offset;

    int64_t gd_offset;

    int64_t grain_offset;

    char filler[1];

    char check_bytes[4];

} VMDK4Header;

#define L2_CACHE_SIZE 16

typedef struct BDRVVmdkState {

    int fd;

    int64_t l1_table_offset;

    uint32_t *l1_table;

    unsigned int l1_size;

    uint32_t l1_entry_sectors;

    unsigned int l2_size;

    uint32_t *l2_cache;

    uint32_t l2_cache_offsets[L2_CACHE_SIZE];

    uint32_t l2_cache_counts[L2_CACHE_SIZE];

    unsigned int cluster_sectors;

} BDRVVmdkState;

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

{

    uint32_t magic;

    if (buf_size < 4)

        return 0;

    magic = be32_to_cpu(*(uint32_t *)buf);

    if (magic == VMDK3_MAGIC ||

        magic == VMDK4_MAGIC)

        return 100;

    else

        return 0;

}

static int vmdk_open(BlockDriverState *bs, const char *filename)

{

    BDRVVmdkState *s = bs->opaque;

    int fd, i;

    uint32_t magic;

    int l1_size;

    fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);

    if (fd < 0)

        return -1;

    if (read(fd, &magic, sizeof(magic)) != sizeof(magic))

        goto fail;

    magic = be32_to_cpu(magic);

    if (magic == VMDK3_MAGIC) {

        VMDK3Header header;

        if (read(fd, &header, sizeof(header)) != 

            sizeof(header))

            goto fail;

        s->cluster_sectors = le32_to_cpu(header.granularity);

        s->l2_size = 1 << 9;

        s->l1_size = 1 << 6;

        bs->total_sectors = le32_to_cpu(header.disk_sectors);

        s->l1_table_offset = le32_to_cpu(header.l1dir_offset) * 512;

        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;

    } else if (magic == VMDK4_MAGIC) {

        VMDK4Header header;

        if (read(fd, &header, sizeof(header)) != sizeof(header))

            goto fail;

        bs->total_sectors = le32_to_cpu(header.capacity);

        s->cluster_sectors = le32_to_cpu(header.granularity);

        s->l2_size = le32_to_cpu(header.num_gtes_per_gte);

        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;

        if (s->l1_entry_sectors <= 0)

            goto fail;

        s->l1_size = (bs->total_sectors + s->l1_entry_sectors - 1) 

            / s->l1_entry_sectors;

        s->l1_table_offset = le64_to_cpu(header.rgd_offset) * 512;

    } else {

        goto fail;

    }

    /* read the L1 table */

    l1_size = s->l1_size * sizeof(uint32_t);

    s->l1_table = qemu_malloc(l1_size);

    if (!s->l1_table)

        goto fail;

    if (lseek(fd, s->l1_table_offset, SEEK_SET) == -1)

        goto fail;

    if (read(fd, s->l1_table, l1_size) != l1_size)

        goto fail;

    for(i = 0; i < s->l1_size; i++) {

        le32_to_cpus(&s->l1_table[i]);

    }

    s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));

    if (!s->l2_cache)

        goto fail;

    s->fd = fd;

    /* XXX: currently only read only */

    bs->read_only = 1;

    return 0;

 fail:

    qemu_free(s->l1_table);

    qemu_free(s->l2_cache);

    close(fd);

    return -1;

}

static uint64_t get_cluster_offset(BlockDriverState *bs,

                                   uint64_t offset)

{

    BDRVVmdkState *s = bs->opaque;

    unsigned int l1_index, l2_offset, l2_index;

    int min_index, i, j;

    uint32_t min_count, *l2_table;

    uint64_t cluster_offset;

    l1_index = (offset >> 9) / s->l1_entry_sectors;

    if (l1_index >= s->l1_size)

        return 0;

    l2_offset = s->l1_table[l1_index];

    if (!l2_offset)

        return 0;

    for(i = 0; i < L2_CACHE_SIZE; i++) {

        if (l2_offset == s->l2_cache_offsets[i]) {

            /* increment the hit count */

            if (++s->l2_cache_counts[i] == 0xffffffff) {

                for(j = 0; j < L2_CACHE_SIZE; j++) {

                    s->l2_cache_counts[j] >>= 1;

                }

            }

            l2_table = s->l2_cache + (i * s->l2_size);

            goto found;

        }

    }

    /* not found: load a new entry in the least used one */

    min_index = 0;

    min_count = 0xffffffff;

    for(i = 0; i < L2_CACHE_SIZE; i++) {

        if (s->l2_cache_counts[i] < min_count) {

            min_count = s->l2_cache_counts[i];

            min_index = i;

        }

    }

    l2_table = s->l2_cache + (min_index * s->l2_size);

    lseek(s->fd, (int64_t)l2_offset * 512, SEEK_SET);

    if (read(s->fd, l2_table, s->l2_size * sizeof(uint32_t)) != 

        s->l2_size * sizeof(uint32_t))

        return 0;

    s->l2_cache_offsets[min_index] = l2_offset;

    s->l2_cache_counts[min_index] = 1;

 found:

    l2_index = ((offset >> 9) / s->cluster_sectors) % s->l2_size;

    cluster_offset = le32_to_cpu(l2_table[l2_index]);

    cluster_offset <<= 9;

    return cluster_offset;

}

static int vmdk_is_allocated(BlockDriverState *bs, int64_t sector_num, 

                             int nb_sectors, int *pnum)

{

    BDRVVmdkState *s = bs->opaque;

    int index_in_cluster, n;

    uint64_t cluster_offset;

    cluster_offset = get_cluster_offset(bs, sector_num << 9);

    index_in_cluster = sector_num % s->cluster_sectors;

    n = s->cluster_sectors - index_in_cluster;

    if (n > nb_sectors)

        n = nb_sectors;

    *pnum = n;

    return (cluster_offset != 0);

}

static int vmdk_read(BlockDriverState *bs, int64_t sector_num, 

                    uint8_t *buf, int nb_sectors)

{

    BDRVVmdkState *s = bs->opaque;

    int ret, index_in_cluster, n;

    uint64_t cluster_offset;

    while (nb_sectors > 0) {

        cluster_offset = get_cluster_offset(bs, sector_num << 9);

        index_in_cluster = sector_num % s->cluster_sectors;

        n = s->cluster_sectors - index_in_cluster;

        if (n > nb_sectors)

            n = nb_sectors;

        if (!cluster_offset) {

            memset(buf, 0, 512 * n);

        } else {

            lseek(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);

            ret = read(s->fd, buf, n * 512);

            if (ret != n * 512) 

                return -1;

        }

        nb_sectors -= n;

        sector_num += n;

        buf += n * 512;

    }

    return 0;

}

static int vmdk_write(BlockDriverState *bs, int64_t sector_num, 

                     const uint8_t *buf, int nb_sectors)

{

    return -1;

}

static void vmdk_close(BlockDriverState *bs)

{

    BDRVVmdkState *s = bs->opaque;

    qemu_free(s->l1_table);

    qemu_free(s->l2_cache);

    close(s->fd);

}

BlockDriver bdrv_vmdk = {

    "vmdk",

    sizeof(BDRVVmdkState),

    vmdk_probe,

    vmdk_open,

    vmdk_read,

    vmdk_write,

    vmdk_close,

    NULL, /* no create yet */

    vmdk_is_allocated,

};