bellard | a8753c3 | 2005-04-26 21:34:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Block driver for the various disk image formats used by Bochs |
| 3 | * Currently only for "growing" type in read-only mode |
| 4 | * |
| 5 | * Copyright (c) 2005 Alex Beregszaszi |
| 6 | * |
| 7 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 8 | * of this software and associated documentation files (the "Software"), to deal |
| 9 | * in the Software without restriction, including without limitation the rights |
| 10 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 11 | * copies of the Software, and to permit persons to whom the Software is |
| 12 | * furnished to do so, subject to the following conditions: |
| 13 | * |
| 14 | * The above copyright notice and this permission notice shall be included in |
| 15 | * all copies or substantial portions of the Software. |
| 16 | * |
| 17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| 20 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 22 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| 23 | * THE SOFTWARE. |
| 24 | */ |
| 25 | #include "vl.h" |
| 26 | #include "block_int.h" |
| 27 | |
| 28 | /**************************************************************/ |
| 29 | |
| 30 | #define HEADER_MAGIC "Bochs Virtual HD Image" |
| 31 | #define HEADER_VERSION 0x00010000 |
| 32 | #define HEADER_SIZE 512 |
| 33 | |
| 34 | #define REDOLOG_TYPE "Redolog" |
| 35 | #define GROWING_TYPE "Growing" |
| 36 | |
| 37 | // not allocated: 0xffffffff |
| 38 | |
| 39 | // always little-endian |
| 40 | struct bochs_header { |
| 41 | char magic[32]; // "Bochs Virtual HD Image" |
| 42 | char type[16]; // "Redolog" |
| 43 | char subtype[16]; // "Undoable" / "Volatile" / "Growing" |
| 44 | uint32_t version; |
| 45 | uint32_t header; // size of header |
| 46 | |
| 47 | union { |
| 48 | struct { |
| 49 | uint32_t catalog; // num of entries |
| 50 | uint32_t bitmap; // bitmap size |
| 51 | uint32_t extent; // extent size |
| 52 | uint64_t disk; // disk size |
| 53 | char padding[HEADER_SIZE - 64 - 8 - 20]; |
| 54 | } redolog; |
| 55 | char padding[HEADER_SIZE - 64 - 8]; |
| 56 | } extra; |
| 57 | }; |
| 58 | |
| 59 | typedef struct BDRVBochsState { |
| 60 | int fd; |
| 61 | |
| 62 | uint32_t *catalog_bitmap; |
| 63 | int catalog_size; |
| 64 | |
| 65 | int data_offset; |
| 66 | |
| 67 | int bitmap_blocks; |
| 68 | int extent_blocks; |
| 69 | int extent_size; |
| 70 | } BDRVBochsState; |
| 71 | |
| 72 | static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename) |
| 73 | { |
| 74 | const struct bochs_header *bochs = (const void *)buf; |
| 75 | |
| 76 | if (buf_size < HEADER_SIZE) |
| 77 | return 0; |
| 78 | |
| 79 | if (!strcmp(bochs->magic, HEADER_MAGIC) && |
| 80 | !strcmp(bochs->type, REDOLOG_TYPE) && |
| 81 | !strcmp(bochs->subtype, GROWING_TYPE) && |
| 82 | (le32_to_cpu(bochs->version) == HEADER_VERSION)) |
| 83 | return 100; |
| 84 | |
| 85 | return 0; |
| 86 | } |
| 87 | |
| 88 | static int bochs_open(BlockDriverState *bs, const char *filename) |
| 89 | { |
| 90 | BDRVBochsState *s = bs->opaque; |
| 91 | int fd, i; |
| 92 | struct bochs_header bochs; |
| 93 | |
| 94 | fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE); |
| 95 | if (fd < 0) { |
| 96 | fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE); |
| 97 | if (fd < 0) |
| 98 | return -1; |
| 99 | } |
| 100 | |
| 101 | bs->read_only = 1; // no write support yet |
| 102 | |
| 103 | s->fd = fd; |
| 104 | |
| 105 | if (read(fd, &bochs, sizeof(bochs)) != sizeof(bochs)) { |
| 106 | goto fail; |
| 107 | } |
| 108 | |
| 109 | if (strcmp(bochs.magic, HEADER_MAGIC) || |
| 110 | strcmp(bochs.type, REDOLOG_TYPE) || |
| 111 | strcmp(bochs.subtype, GROWING_TYPE) || |
| 112 | (le32_to_cpu(bochs.version) != HEADER_VERSION)) { |
| 113 | goto fail; |
| 114 | } |
| 115 | |
| 116 | bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512; |
| 117 | |
| 118 | lseek(s->fd, le32_to_cpu(bochs.header), SEEK_SET); |
| 119 | |
| 120 | s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog); |
| 121 | s->catalog_bitmap = qemu_malloc(s->catalog_size * 4); |
| 122 | if (!s->catalog_bitmap) |
| 123 | goto fail; |
| 124 | if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) != |
| 125 | s->catalog_size * 4) |
| 126 | goto fail; |
| 127 | for (i = 0; i < s->catalog_size; i++) |
| 128 | le32_to_cpus(&s->catalog_bitmap[i]); |
| 129 | |
| 130 | s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4); |
| 131 | |
| 132 | s->bitmap_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.bitmap) - 1) / 512; |
| 133 | s->extent_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.extent) - 1) / 512; |
| 134 | |
| 135 | s->extent_size = le32_to_cpu(bochs.extra.redolog.extent); |
| 136 | |
| 137 | return 0; |
| 138 | fail: |
| 139 | close(fd); |
| 140 | return -1; |
| 141 | } |
| 142 | |
| 143 | static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) |
| 144 | { |
| 145 | BDRVBochsState *s = bs->opaque; |
| 146 | int64_t offset = sector_num * 512; |
| 147 | int64_t extent_index, extent_offset, bitmap_offset, block_offset; |
| 148 | char bitmap_entry; |
| 149 | |
| 150 | // seek to sector |
| 151 | extent_index = offset / s->extent_size; |
| 152 | extent_offset = (offset % s->extent_size) / 512; |
| 153 | |
| 154 | if (s->catalog_bitmap[extent_index] == 0xffffffff) |
| 155 | { |
| 156 | // fprintf(stderr, "page not allocated [%x - %x:%x]\n", |
| 157 | // sector_num, extent_index, extent_offset); |
| 158 | return -1; // not allocated |
| 159 | } |
| 160 | |
| 161 | bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] * |
| 162 | (s->extent_blocks + s->bitmap_blocks)); |
| 163 | block_offset = bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); |
| 164 | |
| 165 | // fprintf(stderr, "sect: %x [ext i: %x o: %x] -> %x bitmap: %x block: %x\n", |
| 166 | // sector_num, extent_index, extent_offset, |
| 167 | // le32_to_cpu(s->catalog_bitmap[extent_index]), |
| 168 | // bitmap_offset, block_offset); |
| 169 | |
| 170 | // read in bitmap for current extent |
| 171 | lseek(s->fd, bitmap_offset + (extent_offset / 8), SEEK_SET); |
| 172 | |
| 173 | read(s->fd, &bitmap_entry, 1); |
| 174 | |
| 175 | if (!((bitmap_entry >> (extent_offset % 8)) & 1)) |
| 176 | { |
| 177 | // fprintf(stderr, "sector (%x) in bitmap not allocated\n", |
| 178 | // sector_num); |
| 179 | return -1; // not allocated |
| 180 | } |
| 181 | |
| 182 | lseek(s->fd, block_offset, SEEK_SET); |
| 183 | |
| 184 | return 0; |
| 185 | } |
| 186 | |
| 187 | static int bochs_read(BlockDriverState *bs, int64_t sector_num, |
| 188 | uint8_t *buf, int nb_sectors) |
| 189 | { |
| 190 | BDRVBochsState *s = bs->opaque; |
| 191 | int ret; |
| 192 | |
| 193 | while (nb_sectors > 0) { |
| 194 | if (!seek_to_sector(bs, sector_num)) |
| 195 | { |
| 196 | ret = read(s->fd, buf, 512); |
| 197 | if (ret != 512) |
| 198 | return -1; |
| 199 | } |
| 200 | else |
| 201 | memset(buf, 0, 512); |
| 202 | nb_sectors--; |
| 203 | sector_num++; |
| 204 | buf += 512; |
| 205 | } |
| 206 | return 0; |
| 207 | } |
| 208 | |
| 209 | static void bochs_close(BlockDriverState *bs) |
| 210 | { |
| 211 | BDRVBochsState *s = bs->opaque; |
| 212 | qemu_free(s->catalog_bitmap); |
| 213 | close(s->fd); |
| 214 | } |
| 215 | |
| 216 | BlockDriver bdrv_bochs = { |
| 217 | "bochs", |
| 218 | sizeof(BDRVBochsState), |
| 219 | bochs_probe, |
| 220 | bochs_open, |
| 221 | bochs_read, |
| 222 | NULL, |
| 223 | bochs_close, |
| 224 | }; |