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/osdep.h" |
26 | #include "qapi/error.h" |
27 | #include "block/block_int.h" |
28 | #include "qemu/module.h" |
29 | #include "qemu/bswap.h" |
30 | #include "qemu/error-report.h" |
31 | |
32 | /**************************************************************/ |
33 | |
34 | #define "Bochs Virtual HD Image" |
35 | #define 0x00020000 |
36 | #define 0x00010000 |
37 | #define 512 |
38 | |
39 | #define REDOLOG_TYPE "Redolog" |
40 | #define GROWING_TYPE "Growing" |
41 | |
42 | // not allocated: 0xffffffff |
43 | |
44 | // always little-endian |
45 | struct { |
46 | char [32]; /* "Bochs Virtual HD Image" */ |
47 | char [16]; /* "Redolog" */ |
48 | char [16]; /* "Undoable" / "Volatile" / "Growing" */ |
49 | uint32_t ; |
50 | uint32_t ; /* size of header */ |
51 | |
52 | uint32_t ; /* num of entries */ |
53 | uint32_t ; /* bitmap size */ |
54 | uint32_t ; /* extent size */ |
55 | |
56 | union { |
57 | struct { |
58 | uint32_t ; /* for ??? */ |
59 | uint64_t ; /* disk size */ |
60 | char [HEADER_SIZE - 64 - 20 - 12]; |
61 | } QEMU_PACKED ; |
62 | struct { |
63 | uint64_t ; /* disk size */ |
64 | char [HEADER_SIZE - 64 - 20 - 8]; |
65 | } QEMU_PACKED ; |
66 | char [HEADER_SIZE - 64 - 20]; |
67 | } ; |
68 | } QEMU_PACKED; |
69 | |
70 | typedef struct BDRVBochsState { |
71 | CoMutex lock; |
72 | uint32_t *catalog_bitmap; |
73 | uint32_t catalog_size; |
74 | |
75 | uint32_t data_offset; |
76 | |
77 | uint32_t bitmap_blocks; |
78 | uint32_t extent_blocks; |
79 | uint32_t extent_size; |
80 | } BDRVBochsState; |
81 | |
82 | static int bochs_probe(const uint8_t *buf, int buf_size, const char *filename) |
83 | { |
84 | const struct bochs_header *bochs = (const void *)buf; |
85 | |
86 | if (buf_size < HEADER_SIZE) |
87 | return 0; |
88 | |
89 | if (!strcmp(bochs->magic, HEADER_MAGIC) && |
90 | !strcmp(bochs->type, REDOLOG_TYPE) && |
91 | !strcmp(bochs->subtype, GROWING_TYPE) && |
92 | ((le32_to_cpu(bochs->version) == HEADER_VERSION) || |
93 | (le32_to_cpu(bochs->version) == HEADER_V1))) |
94 | return 100; |
95 | |
96 | return 0; |
97 | } |
98 | |
99 | static int bochs_open(BlockDriverState *bs, QDict *options, int flags, |
100 | Error **errp) |
101 | { |
102 | BDRVBochsState *s = bs->opaque; |
103 | uint32_t i; |
104 | struct bochs_header bochs; |
105 | int ret; |
106 | |
107 | /* No write support yet */ |
108 | ret = bdrv_apply_auto_read_only(bs, NULL, errp); |
109 | if (ret < 0) { |
110 | return ret; |
111 | } |
112 | |
113 | bs->file = bdrv_open_child(NULL, options, "file" , bs, &child_file, |
114 | false, errp); |
115 | if (!bs->file) { |
116 | return -EINVAL; |
117 | } |
118 | |
119 | ret = bdrv_pread(bs->file, 0, &bochs, sizeof(bochs)); |
120 | if (ret < 0) { |
121 | return ret; |
122 | } |
123 | |
124 | if (strcmp(bochs.magic, HEADER_MAGIC) || |
125 | strcmp(bochs.type, REDOLOG_TYPE) || |
126 | strcmp(bochs.subtype, GROWING_TYPE) || |
127 | ((le32_to_cpu(bochs.version) != HEADER_VERSION) && |
128 | (le32_to_cpu(bochs.version) != HEADER_V1))) { |
129 | error_setg(errp, "Image not in Bochs format" ); |
130 | return -EINVAL; |
131 | } |
132 | |
133 | if (le32_to_cpu(bochs.version) == HEADER_V1) { |
134 | bs->total_sectors = le64_to_cpu(bochs.extra.redolog_v1.disk) / 512; |
135 | } else { |
136 | bs->total_sectors = le64_to_cpu(bochs.extra.redolog.disk) / 512; |
137 | } |
138 | |
139 | /* Limit to 1M entries to avoid unbounded allocation. This is what is |
140 | * needed for the largest image that bximage can create (~8 TB). */ |
141 | s->catalog_size = le32_to_cpu(bochs.catalog); |
142 | if (s->catalog_size > 0x100000) { |
143 | error_setg(errp, "Catalog size is too large" ); |
144 | return -EFBIG; |
145 | } |
146 | |
147 | s->catalog_bitmap = g_try_new(uint32_t, s->catalog_size); |
148 | if (s->catalog_size && s->catalog_bitmap == NULL) { |
149 | error_setg(errp, "Could not allocate memory for catalog" ); |
150 | return -ENOMEM; |
151 | } |
152 | |
153 | ret = bdrv_pread(bs->file, le32_to_cpu(bochs.header), s->catalog_bitmap, |
154 | s->catalog_size * 4); |
155 | if (ret < 0) { |
156 | goto fail; |
157 | } |
158 | |
159 | for (i = 0; i < s->catalog_size; i++) |
160 | le32_to_cpus(&s->catalog_bitmap[i]); |
161 | |
162 | s->data_offset = le32_to_cpu(bochs.header) + (s->catalog_size * 4); |
163 | |
164 | s->bitmap_blocks = 1 + (le32_to_cpu(bochs.bitmap) - 1) / 512; |
165 | s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512; |
166 | |
167 | s->extent_size = le32_to_cpu(bochs.extent); |
168 | if (s->extent_size < BDRV_SECTOR_SIZE) { |
169 | /* bximage actually never creates extents smaller than 4k */ |
170 | error_setg(errp, "Extent size must be at least 512" ); |
171 | ret = -EINVAL; |
172 | goto fail; |
173 | } else if (!is_power_of_2(s->extent_size)) { |
174 | error_setg(errp, "Extent size %" PRIu32 " is not a power of two" , |
175 | s->extent_size); |
176 | ret = -EINVAL; |
177 | goto fail; |
178 | } else if (s->extent_size > 0x800000) { |
179 | error_setg(errp, "Extent size %" PRIu32 " is too large" , |
180 | s->extent_size); |
181 | ret = -EINVAL; |
182 | goto fail; |
183 | } |
184 | |
185 | if (s->catalog_size < DIV_ROUND_UP(bs->total_sectors, |
186 | s->extent_size / BDRV_SECTOR_SIZE)) |
187 | { |
188 | error_setg(errp, "Catalog size is too small for this disk size" ); |
189 | ret = -EINVAL; |
190 | goto fail; |
191 | } |
192 | |
193 | qemu_co_mutex_init(&s->lock); |
194 | return 0; |
195 | |
196 | fail: |
197 | g_free(s->catalog_bitmap); |
198 | return ret; |
199 | } |
200 | |
201 | static void bochs_refresh_limits(BlockDriverState *bs, Error **errp) |
202 | { |
203 | bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */ |
204 | } |
205 | |
206 | static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num) |
207 | { |
208 | BDRVBochsState *s = bs->opaque; |
209 | uint64_t offset = sector_num * 512; |
210 | uint64_t extent_index, extent_offset, bitmap_offset; |
211 | char bitmap_entry; |
212 | int ret; |
213 | |
214 | // seek to sector |
215 | extent_index = offset / s->extent_size; |
216 | extent_offset = (offset % s->extent_size) / 512; |
217 | |
218 | if (s->catalog_bitmap[extent_index] == 0xffffffff) { |
219 | return 0; /* not allocated */ |
220 | } |
221 | |
222 | bitmap_offset = s->data_offset + |
223 | (512 * (uint64_t) s->catalog_bitmap[extent_index] * |
224 | (s->extent_blocks + s->bitmap_blocks)); |
225 | |
226 | /* read in bitmap for current extent */ |
227 | ret = bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8), |
228 | &bitmap_entry, 1); |
229 | if (ret < 0) { |
230 | return ret; |
231 | } |
232 | |
233 | if (!((bitmap_entry >> (extent_offset % 8)) & 1)) { |
234 | return 0; /* not allocated */ |
235 | } |
236 | |
237 | return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset)); |
238 | } |
239 | |
240 | static int coroutine_fn |
241 | bochs_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, |
242 | QEMUIOVector *qiov, int flags) |
243 | { |
244 | BDRVBochsState *s = bs->opaque; |
245 | uint64_t sector_num = offset >> BDRV_SECTOR_BITS; |
246 | int nb_sectors = bytes >> BDRV_SECTOR_BITS; |
247 | uint64_t bytes_done = 0; |
248 | QEMUIOVector local_qiov; |
249 | int ret; |
250 | |
251 | assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); |
252 | assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); |
253 | |
254 | qemu_iovec_init(&local_qiov, qiov->niov); |
255 | qemu_co_mutex_lock(&s->lock); |
256 | |
257 | while (nb_sectors > 0) { |
258 | int64_t block_offset = seek_to_sector(bs, sector_num); |
259 | if (block_offset < 0) { |
260 | ret = block_offset; |
261 | goto fail; |
262 | } |
263 | |
264 | qemu_iovec_reset(&local_qiov); |
265 | qemu_iovec_concat(&local_qiov, qiov, bytes_done, 512); |
266 | |
267 | if (block_offset > 0) { |
268 | ret = bdrv_co_preadv(bs->file, block_offset, 512, |
269 | &local_qiov, 0); |
270 | if (ret < 0) { |
271 | goto fail; |
272 | } |
273 | } else { |
274 | qemu_iovec_memset(&local_qiov, 0, 0, 512); |
275 | } |
276 | nb_sectors--; |
277 | sector_num++; |
278 | bytes_done += 512; |
279 | } |
280 | |
281 | ret = 0; |
282 | fail: |
283 | qemu_co_mutex_unlock(&s->lock); |
284 | qemu_iovec_destroy(&local_qiov); |
285 | |
286 | return ret; |
287 | } |
288 | |
289 | static void bochs_close(BlockDriverState *bs) |
290 | { |
291 | BDRVBochsState *s = bs->opaque; |
292 | g_free(s->catalog_bitmap); |
293 | } |
294 | |
295 | static BlockDriver bdrv_bochs = { |
296 | .format_name = "bochs" , |
297 | .instance_size = sizeof(BDRVBochsState), |
298 | .bdrv_probe = bochs_probe, |
299 | .bdrv_open = bochs_open, |
300 | .bdrv_child_perm = bdrv_format_default_perms, |
301 | .bdrv_refresh_limits = bochs_refresh_limits, |
302 | .bdrv_co_preadv = bochs_co_preadv, |
303 | .bdrv_close = bochs_close, |
304 | }; |
305 | |
306 | static void bdrv_bochs_init(void) |
307 | { |
308 | bdrv_register(&bdrv_bochs); |
309 | } |
310 | |
311 | block_init(bdrv_bochs_init); |
312 | |