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1.1 root 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);
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