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/*
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 * Block driver for the various disk image formats used by Bochs
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 * Currently only for "growing" type in read-only mode
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 *
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 * Copyright (c) 2005 Alex Beregszaszi
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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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/**************************************************************/
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#define HEADER_MAGIC "Bochs Virtual HD Image"
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#define HEADER_VERSION 0x00020000
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#define HEADER_V1 0x00010000
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#define HEADER_SIZE 512
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#define REDOLOG_TYPE "Redolog"
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#define GROWING_TYPE "Growing"
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// not allocated: 0xffffffff
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// always little-endian
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struct bochs_header_v1 {
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    char magic[32]; // "Bochs Virtual HD Image"
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    char type[16]; // "Redolog"
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    char subtype[16]; // "Undoable" / "Volatile" / "Growing"
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    uint32_t version;
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    uint32_t header; // size of header
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    union {
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        struct {
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            uint32_t catalog; // num of entries
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            uint32_t bitmap; // bitmap size
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            uint32_t extent; // extent size
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            uint64_t disk; // disk size
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            char padding[HEADER_SIZE - 64 - 8 - 20];
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        } redolog;
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        char padding[HEADER_SIZE - 64 - 8];
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    } extra;
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};
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// always little-endian
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struct bochs_header {
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    char magic[32]; // "Bochs Virtual HD Image"
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    char type[16]; // "Redolog"
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    char subtype[16]; // "Undoable" / "Volatile" / "Growing"
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    uint32_t version;
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    uint32_t header; // size of header
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    union {
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        struct {
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            uint32_t catalog; // num of entries
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            uint32_t bitmap; // bitmap size
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            uint32_t extent; // extent size
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            uint32_t reserved; // for ???
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            uint64_t disk; // disk size
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            char padding[HEADER_SIZE - 64 - 8 - 24];
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        } redolog;
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        char padding[HEADER_SIZE - 64 - 8];
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    } extra;
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};
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typedef struct BDRVBochsState {
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    int fd;
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    uint32_t *catalog_bitmap;
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    int catalog_size;
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    int data_offset;
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    int bitmap_blocks;
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    int extent_blocks;
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    int extent_size;
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} BDRVBochsState;
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static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
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{
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    const struct bochs_header *bochs = (const void *)buf;
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    if (buf_size < HEADER_SIZE)
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        return 0;
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    if (!strcmp(bochs->magic, HEADER_MAGIC) &&
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        !strcmp(bochs->type, REDOLOG_TYPE) &&
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        !strcmp(bochs->subtype, GROWING_TYPE) &&
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        ((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
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        (le32_to_cpu(bochs->version) == HEADER_V1)))
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        return 100;
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    return 0;
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}
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static int bochs_open(BlockDriverState *bs, const char *filename, int flags)
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{
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    BDRVBochsState *s = bs->opaque;
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    int fd, i;
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    struct bochs_header bochs;
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    struct bochs_header_v1 header_v1;
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    fd = open(filename, O_RDWR | O_BINARY);
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    if (fd < 0) {
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        fd = open(filename, O_RDONLY | O_BINARY);
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        if (fd < 0)
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            return -1;
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    }
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    bs->read_only = 1; // no write support yet
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    s->fd = fd;
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    if (read(fd, &bochs, sizeof(bochs)) != sizeof(bochs)) {
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        goto fail;
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    }
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    if (strcmp(bochs.magic, HEADER_MAGIC) ||
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        strcmp(bochs.type, REDOLOG_TYPE) ||
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        strcmp(bochs.subtype, GROWING_TYPE) ||
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        ((le32_to_cpu(bochs.version) != HEADER_VERSION) &&
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        (le32_to_cpu(bochs.version) != HEADER_V1))) {
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        goto fail;
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    }
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    if (le32_to_cpu(bochs.version) == HEADER_V1) {
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      memcpy(&header_v1, &bochs, sizeof(bochs));
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      bs->total_sectors = le64_to_cpu(header_v1.extra.redolog.disk) / 512;
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    } else {
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      bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512;
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    }
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    lseek(s->fd, le32_to_cpu(bochs.header), SEEK_SET);
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    s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog);
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    s->catalog_bitmap = qemu_malloc(s->catalog_size * 4);
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    if (!s->catalog_bitmap)
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        goto fail;
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    if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) !=
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        s->catalog_size * 4)
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        goto fail;
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    for (i = 0; i < s->catalog_size; i++)
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        le32_to_cpus(&s->catalog_bitmap[i]);
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    s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4);
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    s->bitmap_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.bitmap) - 1) / 512;
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    s->extent_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.extent) - 1) / 512;
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    s->extent_size = le32_to_cpu(bochs.extra.redolog.extent);
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    return 0;
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 fail:
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    close(fd);
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    return -1;
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}
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static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num)
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{
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    BDRVBochsState *s = bs->opaque;
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    int64_t offset = sector_num * 512;
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    int64_t extent_index, extent_offset, bitmap_offset, block_offset;
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    char bitmap_entry;
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    // seek to sector
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    extent_index = offset / s->extent_size;
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    extent_offset = (offset % s->extent_size) / 512;
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    if (s->catalog_bitmap[extent_index] == 0xffffffff)
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    {
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//        fprintf(stderr, "page not allocated [%x - %x:%x]\n",
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//            sector_num, extent_index, extent_offset);
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        return -1; // not allocated
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    }
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    bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] *
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        (s->extent_blocks + s->bitmap_blocks));
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    block_offset = bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
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//    fprintf(stderr, "sect: %x [ext i: %x o: %x] -> %x bitmap: %x block: %x\n",
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//        sector_num, extent_index, extent_offset,
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//        le32_to_cpu(s->catalog_bitmap[extent_index]),
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//        bitmap_offset, block_offset);
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    // read in bitmap for current extent
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    lseek(s->fd, bitmap_offset + (extent_offset / 8), SEEK_SET);
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    read(s->fd, &bitmap_entry, 1);
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    if (!((bitmap_entry >> (extent_offset % 8)) & 1))
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    {
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//        fprintf(stderr, "sector (%x) in bitmap not allocated\n",
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//            sector_num);
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        return -1; // not allocated
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    }
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    lseek(s->fd, block_offset, SEEK_SET);
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    return 0;
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}
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static int bochs_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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    BDRVBochsState *s = bs->opaque;
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    int ret;
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    while (nb_sectors > 0) {
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        if (!seek_to_sector(bs, sector_num))
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        {
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            ret = read(s->fd, buf, 512);
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            if (ret != 512)
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                return -1;
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        }
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        else
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            memset(buf, 0, 512);
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        nb_sectors--;
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        sector_num++;
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        buf += 512;
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    }
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    return 0;
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}
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static void bochs_close(BlockDriverState *bs)
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{
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    BDRVBochsState *s = bs->opaque;
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    qemu_free(s->catalog_bitmap);
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    close(s->fd);
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}
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BlockDriver bdrv_bochs = {
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    "bochs",
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    sizeof(BDRVBochsState),
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    bochs_probe,
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    bochs_open,
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    bochs_read,
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    NULL,
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    bochs_close,
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};