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baefd977 VSO |
1 | /* |
2 | * Support of Parallels Format Extension. It's a part of Parallels format | |
3 | * driver. | |
4 | * | |
5 | * Copyright (c) 2021 Virtuozzo International GmbH | |
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 | ||
26 | #include "qemu/osdep.h" | |
27 | #include "qapi/error.h" | |
28 | #include "block/block_int.h" | |
29 | #include "parallels.h" | |
30 | #include "crypto/hash.h" | |
31 | #include "qemu/uuid.h" | |
32 | ||
33 | #define PARALLELS_FORMAT_EXTENSION_MAGIC 0xAB234CEF23DCEA87ULL | |
34 | ||
35 | #define PARALLELS_END_OF_FEATURES_MAGIC 0x0ULL | |
36 | #define PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC 0x20385FAE252CB34AULL | |
37 | ||
38 | typedef struct ParallelsFormatExtensionHeader { | |
39 | uint64_t magic; /* PARALLELS_FORMAT_EXTENSION_MAGIC */ | |
40 | uint8_t check_sum[16]; | |
41 | } QEMU_PACKED ParallelsFormatExtensionHeader; | |
42 | ||
43 | typedef struct ParallelsFeatureHeader { | |
44 | uint64_t magic; | |
45 | uint64_t flags; | |
46 | uint32_t data_size; | |
47 | uint32_t _unused; | |
48 | } QEMU_PACKED ParallelsFeatureHeader; | |
49 | ||
50 | typedef struct ParallelsDirtyBitmapFeature { | |
51 | uint64_t size; | |
52 | uint8_t id[16]; | |
53 | uint32_t granularity; | |
54 | uint32_t l1_size; | |
55 | /* L1 table follows */ | |
56 | } QEMU_PACKED ParallelsDirtyBitmapFeature; | |
57 | ||
58 | /* Given L1 table read bitmap data from the image and populate @bitmap */ | |
59 | static int parallels_load_bitmap_data(BlockDriverState *bs, | |
60 | const uint64_t *l1_table, | |
61 | uint32_t l1_size, | |
62 | BdrvDirtyBitmap *bitmap, | |
63 | Error **errp) | |
64 | { | |
65 | BDRVParallelsState *s = bs->opaque; | |
66 | int ret = 0; | |
67 | uint64_t offset, limit; | |
68 | uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap); | |
69 | uint8_t *buf = NULL; | |
70 | uint64_t i, tab_size = | |
71 | DIV_ROUND_UP(bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size), | |
72 | s->cluster_size); | |
73 | ||
74 | if (tab_size != l1_size) { | |
75 | error_setg(errp, "Bitmap table size %" PRIu32 " does not correspond " | |
76 | "to bitmap size and cluster size. Expected %" PRIu64, | |
77 | l1_size, tab_size); | |
78 | return -EINVAL; | |
79 | } | |
80 | ||
81 | buf = qemu_blockalign(bs, s->cluster_size); | |
82 | limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap); | |
83 | for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) { | |
84 | uint64_t count = MIN(bm_size - offset, limit); | |
85 | uint64_t entry = l1_table[i]; | |
86 | ||
87 | if (entry == 0) { | |
88 | /* No need to deserialize zeros because @bitmap is cleared. */ | |
89 | continue; | |
90 | } | |
91 | ||
92 | if (entry == 1) { | |
93 | bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count, false); | |
94 | } else { | |
95 | ret = bdrv_pread(bs->file, entry << BDRV_SECTOR_BITS, buf, | |
96 | s->cluster_size); | |
97 | if (ret < 0) { | |
98 | error_setg_errno(errp, -ret, | |
99 | "Failed to read bitmap data cluster"); | |
100 | goto finish; | |
101 | } | |
102 | bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count, | |
103 | false); | |
104 | } | |
105 | } | |
106 | ret = 0; | |
107 | ||
108 | bdrv_dirty_bitmap_deserialize_finish(bitmap); | |
109 | ||
110 | finish: | |
111 | qemu_vfree(buf); | |
112 | ||
113 | return ret; | |
114 | } | |
115 | ||
116 | /* | |
117 | * @data buffer (of @data_size size) is the Dirty bitmaps feature which | |
118 | * consists of ParallelsDirtyBitmapFeature followed by L1 table. | |
119 | */ | |
120 | static BdrvDirtyBitmap *parallels_load_bitmap(BlockDriverState *bs, | |
121 | uint8_t *data, | |
122 | size_t data_size, | |
123 | Error **errp) | |
124 | { | |
125 | int ret; | |
126 | ParallelsDirtyBitmapFeature bf; | |
127 | g_autofree uint64_t *l1_table = NULL; | |
128 | BdrvDirtyBitmap *bitmap; | |
129 | QemuUUID uuid; | |
130 | char uuidstr[UUID_FMT_LEN + 1]; | |
131 | int i; | |
132 | ||
133 | if (data_size < sizeof(bf)) { | |
134 | error_setg(errp, "Too small Bitmap Feature area in Parallels Format " | |
135 | "Extension: %zu bytes, expected at least %zu bytes", | |
136 | data_size, sizeof(bf)); | |
137 | return NULL; | |
138 | } | |
139 | memcpy(&bf, data, sizeof(bf)); | |
140 | bf.size = le64_to_cpu(bf.size); | |
141 | bf.granularity = le32_to_cpu(bf.granularity) << BDRV_SECTOR_BITS; | |
142 | bf.l1_size = le32_to_cpu(bf.l1_size); | |
143 | data += sizeof(bf); | |
144 | data_size -= sizeof(bf); | |
145 | ||
146 | if (bf.size != bs->total_sectors) { | |
147 | error_setg(errp, "Bitmap size (in sectors) %" PRId64 " differs from " | |
148 | "disk size in sectors %" PRId64, bf.size, bs->total_sectors); | |
149 | return NULL; | |
150 | } | |
151 | ||
152 | if (bf.l1_size * sizeof(uint64_t) > data_size) { | |
153 | error_setg(errp, "Bitmaps feature corrupted: l1 table exceeds " | |
154 | "extension data_size"); | |
155 | return NULL; | |
156 | } | |
157 | ||
158 | memcpy(&uuid, bf.id, sizeof(uuid)); | |
159 | qemu_uuid_unparse(&uuid, uuidstr); | |
160 | bitmap = bdrv_create_dirty_bitmap(bs, bf.granularity, uuidstr, errp); | |
161 | if (!bitmap) { | |
162 | return NULL; | |
163 | } | |
164 | ||
165 | l1_table = g_new(uint64_t, bf.l1_size); | |
166 | for (i = 0; i < bf.l1_size; i++, data += sizeof(uint64_t)) { | |
167 | l1_table[i] = ldq_le_p(data); | |
168 | } | |
169 | ||
170 | ret = parallels_load_bitmap_data(bs, l1_table, bf.l1_size, bitmap, errp); | |
171 | if (ret < 0) { | |
172 | bdrv_release_dirty_bitmap(bitmap); | |
173 | return NULL; | |
174 | } | |
175 | ||
176 | /* We support format extension only for RO parallels images. */ | |
177 | assert(!(bs->open_flags & BDRV_O_RDWR)); | |
178 | bdrv_dirty_bitmap_set_readonly(bitmap, true); | |
179 | ||
180 | return bitmap; | |
181 | } | |
182 | ||
183 | static int parallels_parse_format_extension(BlockDriverState *bs, | |
184 | uint8_t *ext_cluster, Error **errp) | |
185 | { | |
186 | BDRVParallelsState *s = bs->opaque; | |
187 | int ret; | |
188 | int remaining = s->cluster_size; | |
189 | uint8_t *pos = ext_cluster; | |
190 | ParallelsFormatExtensionHeader eh; | |
191 | g_autofree uint8_t *hash = NULL; | |
192 | size_t hash_len = 0; | |
193 | GSList *bitmaps = NULL, *el; | |
194 | ||
195 | memcpy(&eh, pos, sizeof(eh)); | |
196 | eh.magic = le64_to_cpu(eh.magic); | |
197 | pos += sizeof(eh); | |
198 | remaining -= sizeof(eh); | |
199 | ||
200 | if (eh.magic != PARALLELS_FORMAT_EXTENSION_MAGIC) { | |
201 | error_setg(errp, "Wrong parallels Format Extension magic: 0x%" PRIx64 | |
202 | ", expected: 0x%llx", eh.magic, | |
203 | PARALLELS_FORMAT_EXTENSION_MAGIC); | |
204 | goto fail; | |
205 | } | |
206 | ||
207 | ret = qcrypto_hash_bytes(QCRYPTO_HASH_ALG_MD5, (char *)pos, remaining, | |
208 | &hash, &hash_len, errp); | |
209 | if (ret < 0) { | |
210 | goto fail; | |
211 | } | |
212 | ||
213 | if (hash_len != sizeof(eh.check_sum) || | |
214 | memcmp(hash, eh.check_sum, sizeof(eh.check_sum)) != 0) { | |
215 | error_setg(errp, "Wrong checksum in Format Extension header. Format " | |
216 | "extension is corrupted."); | |
217 | goto fail; | |
218 | } | |
219 | ||
220 | while (true) { | |
221 | ParallelsFeatureHeader fh; | |
222 | BdrvDirtyBitmap *bitmap; | |
223 | ||
224 | if (remaining < sizeof(fh)) { | |
225 | error_setg(errp, "Can not read feature header, as remaining bytes " | |
226 | "(%d) in Format Extension is less than Feature header " | |
227 | "size (%zu)", remaining, sizeof(fh)); | |
228 | goto fail; | |
229 | } | |
230 | ||
231 | memcpy(&fh, pos, sizeof(fh)); | |
232 | pos += sizeof(fh); | |
233 | remaining -= sizeof(fh); | |
234 | ||
235 | fh.magic = le64_to_cpu(fh.magic); | |
236 | fh.flags = le64_to_cpu(fh.flags); | |
237 | fh.data_size = le32_to_cpu(fh.data_size); | |
238 | ||
239 | if (fh.flags) { | |
240 | error_setg(errp, "Flags for extension feature are unsupported"); | |
241 | goto fail; | |
242 | } | |
243 | ||
244 | if (fh.data_size > remaining) { | |
245 | error_setg(errp, "Feature data_size exceedes Format Extension " | |
246 | "cluster"); | |
247 | goto fail; | |
248 | } | |
249 | ||
250 | switch (fh.magic) { | |
251 | case PARALLELS_END_OF_FEATURES_MAGIC: | |
252 | return 0; | |
253 | ||
254 | case PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC: | |
255 | bitmap = parallels_load_bitmap(bs, pos, fh.data_size, errp); | |
256 | if (!bitmap) { | |
257 | goto fail; | |
258 | } | |
259 | bitmaps = g_slist_append(bitmaps, bitmap); | |
260 | break; | |
261 | ||
262 | default: | |
263 | error_setg(errp, "Unknown feature: 0x%" PRIu64, fh.magic); | |
264 | goto fail; | |
265 | } | |
266 | ||
267 | pos = ext_cluster + QEMU_ALIGN_UP(pos + fh.data_size - ext_cluster, 8); | |
268 | } | |
269 | ||
270 | fail: | |
271 | for (el = bitmaps; el; el = el->next) { | |
272 | bdrv_release_dirty_bitmap(el->data); | |
273 | } | |
274 | g_slist_free(bitmaps); | |
275 | ||
276 | return -EINVAL; | |
277 | } | |
278 | ||
279 | int parallels_read_format_extension(BlockDriverState *bs, | |
280 | int64_t ext_off, Error **errp) | |
281 | { | |
282 | BDRVParallelsState *s = bs->opaque; | |
283 | int ret; | |
284 | uint8_t *ext_cluster = qemu_blockalign(bs, s->cluster_size); | |
285 | ||
286 | assert(ext_off > 0); | |
287 | ||
288 | ret = bdrv_pread(bs->file, ext_off, ext_cluster, s->cluster_size); | |
289 | if (ret < 0) { | |
290 | error_setg_errno(errp, -ret, "Failed to read Format Extension cluster"); | |
291 | goto out; | |
292 | } | |
293 | ||
294 | ret = parallels_parse_format_extension(bs, ext_cluster, errp); | |
295 | ||
296 | out: | |
297 | qemu_vfree(ext_cluster); | |
298 | ||
299 | return ret; | |
300 | } |