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 "qemu-common.h" 26 #include "block_int.h" 27 #include "module.h" 28 29 /**************************************************************/ 30 31 #define HEADER_MAGIC "Bochs Virtual HD Image" 32 #define HEADER_VERSION 0x00020000 33 #define HEADER_V1 0x00010000 34 #define HEADER_SIZE 512 35 36 #define REDOLOG_TYPE "Redolog" 37 #define GROWING_TYPE "Growing" 38 39 // not allocated: 0xffffffff 40 41 // always little-endian 42 struct bochs_header_v1 { 43 char magic[32]; // "Bochs Virtual HD Image" 44 char type[16]; // "Redolog" 45 char subtype[16]; // "Undoable" / "Volatile" / "Growing" 46 uint32_t version; 47 uint32_t header; // size of header 48 49 union { 50 struct { 51 uint32_t catalog; // num of entries 52 uint32_t bitmap; // bitmap size 53 uint32_t extent; // extent size 54 uint64_t disk; // disk size 55 char padding[HEADER_SIZE - 64 - 8 - 20]; 56 } redolog; 57 char padding[HEADER_SIZE - 64 - 8]; 58 } extra; 59 }; 60 61 // always little-endian 62 struct bochs_header { 63 char magic[32]; // "Bochs Virtual HD Image" 64 char type[16]; // "Redolog" 65 char subtype[16]; // "Undoable" / "Volatile" / "Growing" 66 uint32_t version; 67 uint32_t header; // size of header 68 69 union { 70 struct { 71 uint32_t catalog; // num of entries 72 uint32_t bitmap; // bitmap size 73 uint32_t extent; // extent size 74 uint32_t reserved; // for ??? 75 uint64_t disk; // disk size 76 char padding[HEADER_SIZE - 64 - 8 - 24]; 77 } redolog; 78 char padding[HEADER_SIZE - 64 - 8]; 79 } extra; 80 }; 81 82 typedef struct BDRVBochsState { 83 int fd; 84 85 uint32_t *catalog_bitmap; 86 int catalog_size; 87 88 int data_offset; 89 90 int bitmap_blocks; 91 int extent_blocks; 92 int extent_size; 93 } BDRVBochsState; 94 95 static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename) 96 { 97 const struct bochs_header *bochs = (const void *)buf; 98 99 if (buf_size < HEADER_SIZE) 100 return 0; 101 102 if (!strcmp(bochs->magic, HEADER_MAGIC) && 103 !strcmp(bochs->type, REDOLOG_TYPE) && 104 !strcmp(bochs->subtype, GROWING_TYPE) && 105 ((le32_to_cpu(bochs->version) == HEADER_VERSION) || 106 (le32_to_cpu(bochs->version) == HEADER_V1))) 107 return 100; 108 109 return 0; 110 } 111 112 static int bochs_open(BlockDriverState *bs, const char *filename, int flags) 113 { 114 BDRVBochsState *s = bs->opaque; 115 int fd, i; 116 struct bochs_header bochs; 117 struct bochs_header_v1 header_v1; 118 119 fd = open(filename, O_RDWR | O_BINARY); 120 if (fd < 0) { 121 fd = open(filename, O_RDONLY | O_BINARY); 122 if (fd < 0) 123 return -1; 124 } 125 126 bs->read_only = 1; // no write support yet 127 128 s->fd = fd; 129 130 if (read(fd, &bochs, sizeof(bochs)) != sizeof(bochs)) { 131 goto fail; 132 } 133 134 if (strcmp(bochs.magic, HEADER_MAGIC) || 135 strcmp(bochs.type, REDOLOG_TYPE) || 136 strcmp(bochs.subtype, GROWING_TYPE) || 137 ((le32_to_cpu(bochs.version) != HEADER_VERSION) && 138 (le32_to_cpu(bochs.version) != HEADER_V1))) { 139 goto fail; 140 } 141 142 if (le32_to_cpu(bochs.version) == HEADER_V1) { 143 memcpy(&header_v1, &bochs, sizeof(bochs)); 144 bs->total_sectors = le64_to_cpu(header_v1.extra.redolog.disk) / 512; 145 } else { 146 bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512; 147 } 148 149 lseek(s->fd, le32_to_cpu(bochs.header), SEEK_SET); 150 151 s->catalog_size = le32_to_cpu(bochs.extra.redolog.catalog); 152 s->catalog_bitmap = qemu_malloc(s->catalog_size * 4); 153 if (read(s->fd, s->catalog_bitmap, s->catalog_size * 4) != 154 s->catalog_size * 4) 155 goto fail; 156 for (i = 0; i < s->catalog_size; i++) 157 le32_to_cpus(&s->catalog_bitmap[i]); 158 159 s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4); 160 161 s->bitmap_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.bitmap) - 1) / 512; 162 s->extent_blocks = 1 + (le32_to_cpu(bochs.extra.redolog.extent) - 1) / 512; 163 164 s->extent_size = le32_to_cpu(bochs.extra.redolog.extent); 165 166 return 0; 167 fail: 168 close(fd); 169 return -1; 170 } 171 172 static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) 173 { 174 BDRVBochsState *s = bs->opaque; 175 int64_t offset = sector_num * 512; 176 int64_t extent_index, extent_offset, bitmap_offset, block_offset; 177 char bitmap_entry; 178 179 // seek to sector 180 extent_index = offset / s->extent_size; 181 extent_offset = (offset % s->extent_size) / 512; 182 183 if (s->catalog_bitmap[extent_index] == 0xffffffff) 184 { 185 // fprintf(stderr, "page not allocated [%x - %x:%x]\n", 186 // sector_num, extent_index, extent_offset); 187 return -1; // not allocated 188 } 189 190 bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] * 191 (s->extent_blocks + s->bitmap_blocks)); 192 block_offset = bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); 193 194 // fprintf(stderr, "sect: %x [ext i: %x o: %x] -> %x bitmap: %x block: %x\n", 195 // sector_num, extent_index, extent_offset, 196 // le32_to_cpu(s->catalog_bitmap[extent_index]), 197 // bitmap_offset, block_offset); 198 199 // read in bitmap for current extent 200 lseek(s->fd, bitmap_offset + (extent_offset / 8), SEEK_SET); 201 202 read(s->fd, &bitmap_entry, 1); 203 204 if (!((bitmap_entry >> (extent_offset % 8)) & 1)) 205 { 206 // fprintf(stderr, "sector (%x) in bitmap not allocated\n", 207 // sector_num); 208 return -1; // not allocated 209 } 210 211 lseek(s->fd, block_offset, SEEK_SET); 212 213 return 0; 214 } 215 216 static int bochs_read(BlockDriverState *bs, int64_t sector_num, 217 uint8_t *buf, int nb_sectors) 218 { 219 BDRVBochsState *s = bs->opaque; 220 int ret; 221 222 while (nb_sectors > 0) { 223 if (!seek_to_sector(bs, sector_num)) 224 { 225 ret = read(s->fd, buf, 512); 226 if (ret != 512) 227 return -1; 228 } 229 else 230 memset(buf, 0, 512); 231 nb_sectors--; 232 sector_num++; 233 buf += 512; 234 } 235 return 0; 236 } 237 238 static void bochs_close(BlockDriverState *bs) 239 { 240 BDRVBochsState *s = bs->opaque; 241 qemu_free(s->catalog_bitmap); 242 close(s->fd); 243 } 244 245 static BlockDriver bdrv_bochs = { 246 .format_name = "bochs", 247 .instance_size = sizeof(BDRVBochsState), 248 .bdrv_probe = bochs_probe, 249 .bdrv_open = bochs_open, 250 .bdrv_read = bochs_read, 251 .bdrv_close = bochs_close, 252 }; 253 254 static void bdrv_bochs_init(void) 255 { 256 bdrv_register(&bdrv_bochs); 257 } 258 259 block_init(bdrv_bochs_init); 260
