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/*
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 * Block driver for the VMDK format
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 * 
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 * Copyright (c) 2004 Fabrice Bellard
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 * 
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * of this software and associated documentation files (the "Software"), to deal
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 * in the Software without restriction, including without limitation the rights
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the Software is
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 * furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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 * THE SOFTWARE.
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 */
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#include "vl.h"
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#include "block_int.h"
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/* XXX: this code is untested */
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/* XXX: add write support */
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#define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D')
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#define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
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typedef struct {
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    uint32_t version;
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    uint32_t flags;
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    uint32_t disk_sectors;
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    uint32_t granularity;
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    uint32_t l1dir_offset;
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    uint32_t l1dir_size;
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    uint32_t file_sectors;
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    uint32_t cylinders;
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    uint32_t heads;
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    uint32_t sectors_per_track;
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} VMDK3Header;
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typedef struct {
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    uint32_t version;
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    uint32_t flags;
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    int64_t capacity;
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    int64_t granularity;
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    int64_t desc_offset;
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    int64_t desc_size;
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    int32_t num_gtes_per_gte;
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    int64_t rgd_offset;
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    int64_t gd_offset;
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    int64_t grain_offset;
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    char filler[1];
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    char check_bytes[4];
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} VMDK4Header;
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#define L2_CACHE_SIZE 16
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typedef struct BDRVVmdkState {
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    int fd;
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    int64_t l1_table_offset;
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    uint32_t *l1_table;
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    unsigned int l1_size;
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    uint32_t l1_entry_sectors;
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    unsigned int l2_size;
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    uint32_t *l2_cache;
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    uint32_t l2_cache_offsets[L2_CACHE_SIZE];
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    uint32_t l2_cache_counts[L2_CACHE_SIZE];
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    unsigned int cluster_sectors;
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} BDRVVmdkState;
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static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
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{
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    uint32_t magic;
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    if (buf_size < 4)
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        return 0;
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    magic = be32_to_cpu(*(uint32_t *)buf);
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    if (magic == VMDK3_MAGIC ||
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        magic == VMDK4_MAGIC)
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        return 100;
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    else
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        return 0;
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}
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static int vmdk_open(BlockDriverState *bs, const char *filename)
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{
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    BDRVVmdkState *s = bs->opaque;
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    int fd, i;
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    uint32_t magic;
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    int l1_size;
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    fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
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    if (fd < 0)
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        return -1;
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    if (read(fd, &magic, sizeof(magic)) != sizeof(magic))
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        goto fail;
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    magic = be32_to_cpu(magic);
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    if (magic == VMDK3_MAGIC) {
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        VMDK3Header header;
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        if (read(fd, &header, sizeof(header)) != 
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            sizeof(header))
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            goto fail;
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        s->cluster_sectors = le32_to_cpu(header.granularity);
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        s->l2_size = 1 << 9;
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        s->l1_size = 1 << 6;
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        bs->total_sectors = le32_to_cpu(header.disk_sectors);
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        s->l1_table_offset = le32_to_cpu(header.l1dir_offset) * 512;
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        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
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    } else if (magic == VMDK4_MAGIC) {
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        VMDK4Header header;
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        if (read(fd, &header, sizeof(header)) != sizeof(header))
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            goto fail;
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        bs->total_sectors = le32_to_cpu(header.capacity);
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        s->cluster_sectors = le32_to_cpu(header.granularity);
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        s->l2_size = le32_to_cpu(header.num_gtes_per_gte);
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        s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
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        if (s->l1_entry_sectors <= 0)
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            goto fail;
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        s->l1_size = (bs->total_sectors + s->l1_entry_sectors - 1) 
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            / s->l1_entry_sectors;
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        s->l1_table_offset = le64_to_cpu(header.rgd_offset) * 512;
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    } else {
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        goto fail;
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    }
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    /* read the L1 table */
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    l1_size = s->l1_size * sizeof(uint32_t);
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    s->l1_table = qemu_malloc(l1_size);
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    if (!s->l1_table)
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        goto fail;
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    if (lseek(fd, s->l1_table_offset, SEEK_SET) == -1)
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        goto fail;
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    if (read(fd, s->l1_table, l1_size) != l1_size)
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        goto fail;
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    for(i = 0; i < s->l1_size; i++) {
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        le32_to_cpus(&s->l1_table[i]);
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    }
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    s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));
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    if (!s->l2_cache)
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        goto fail;
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    s->fd = fd;
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    /* XXX: currently only read only */
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    bs->read_only = 1;
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    return 0;
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 fail:
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    qemu_free(s->l1_table);
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    qemu_free(s->l2_cache);
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    close(fd);
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    return -1;
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}
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static uint64_t get_cluster_offset(BlockDriverState *bs,
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                                   uint64_t offset)
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{
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    BDRVVmdkState *s = bs->opaque;
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    unsigned int l1_index, l2_offset, l2_index;
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    int min_index, i, j;
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    uint32_t min_count, *l2_table;
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    uint64_t cluster_offset;
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    l1_index = (offset >> 9) / s->l1_entry_sectors;
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    if (l1_index >= s->l1_size)
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        return 0;
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    l2_offset = s->l1_table[l1_index];
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    if (!l2_offset)
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        return 0;
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    for(i = 0; i < L2_CACHE_SIZE; i++) {
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        if (l2_offset == s->l2_cache_offsets[i]) {
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            /* increment the hit count */
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            if (++s->l2_cache_counts[i] == 0xffffffff) {
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                for(j = 0; j < L2_CACHE_SIZE; j++) {
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                    s->l2_cache_counts[j] >>= 1;
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                }
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            }
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            l2_table = s->l2_cache + (i * s->l2_size);
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            goto found;
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        }
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    }
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    /* not found: load a new entry in the least used one */
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    min_index = 0;
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    min_count = 0xffffffff;
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    for(i = 0; i < L2_CACHE_SIZE; i++) {
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        if (s->l2_cache_counts[i] < min_count) {
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            min_count = s->l2_cache_counts[i];
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            min_index = i;
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        }
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    }
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    l2_table = s->l2_cache + (min_index * s->l2_size);
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    lseek(s->fd, (int64_t)l2_offset * 512, SEEK_SET);
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    if (read(s->fd, l2_table, s->l2_size * sizeof(uint32_t)) != 
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        s->l2_size * sizeof(uint32_t))
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        return 0;
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    s->l2_cache_offsets[min_index] = l2_offset;
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    s->l2_cache_counts[min_index] = 1;
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 found:
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    l2_index = ((offset >> 9) / s->cluster_sectors) % s->l2_size;
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    cluster_offset = le32_to_cpu(l2_table[l2_index]);
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    cluster_offset <<= 9;
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    return cluster_offset;
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}
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static int vmdk_is_allocated(BlockDriverState *bs, int64_t sector_num, 
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                             int nb_sectors, int *pnum)
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{
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    BDRVVmdkState *s = bs->opaque;
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    int index_in_cluster, n;
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    uint64_t cluster_offset;
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    cluster_offset = get_cluster_offset(bs, sector_num << 9);
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    index_in_cluster = sector_num % s->cluster_sectors;
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    n = s->cluster_sectors - index_in_cluster;
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    if (n > nb_sectors)
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        n = nb_sectors;
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    *pnum = n;
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    return (cluster_offset != 0);
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}
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static int vmdk_read(BlockDriverState *bs, int64_t sector_num, 
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                    uint8_t *buf, int nb_sectors)
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{
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    BDRVVmdkState *s = bs->opaque;
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    int ret, index_in_cluster, n;
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    uint64_t cluster_offset;
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    while (nb_sectors > 0) {
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        cluster_offset = get_cluster_offset(bs, sector_num << 9);
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        index_in_cluster = sector_num % s->cluster_sectors;
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        n = s->cluster_sectors - index_in_cluster;
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        if (n > nb_sectors)
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            n = nb_sectors;
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        if (!cluster_offset) {
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            memset(buf, 0, 512 * n);
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        } else {
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            lseek(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);
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            ret = read(s->fd, buf, n * 512);
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            if (ret != n * 512) 
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                return -1;
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        }
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        nb_sectors -= n;
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        sector_num += n;
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        buf += n * 512;
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    }
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    return 0;
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}
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static int vmdk_write(BlockDriverState *bs, int64_t sector_num, 
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                     const uint8_t *buf, int nb_sectors)
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{
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    return -1;
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}
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static void vmdk_close(BlockDriverState *bs)
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{
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    BDRVVmdkState *s = bs->opaque;
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    qemu_free(s->l1_table);
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    qemu_free(s->l2_cache);
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    close(s->fd);
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}
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BlockDriver bdrv_vmdk = {
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    "vmdk",
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    sizeof(BDRVVmdkState),
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    vmdk_probe,
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    vmdk_open,
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    vmdk_read,
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    vmdk_write,
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    vmdk_close,
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    NULL, /* no create yet */
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    vmdk_is_allocated,
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};