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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
edce2aed LP |
2 | |
3 | #include <zlib.h> | |
4 | ||
b5efdb8a | 5 | #include "alloc-util.h" |
1c7dd825 | 6 | #include "btrfs-util.h" |
b5efdb8a LP |
7 | #include "qcow2-util.h" |
8 | #include "sparse-endian.h" | |
9 | #include "util.h" | |
edce2aed LP |
10 | |
11 | #define QCOW2_MAGIC 0x514649fb | |
12 | ||
13 | #define QCOW2_COPIED (1ULL << 63) | |
14 | #define QCOW2_COMPRESSED (1ULL << 62) | |
15 | #define QCOW2_ZERO (1ULL << 0) | |
16 | ||
17 | typedef struct _packed_ Header { | |
18 | be32_t magic; | |
19 | be32_t version; | |
20 | ||
21 | be64_t backing_file_offset; | |
22 | be32_t backing_file_size; | |
23 | ||
24 | be32_t cluster_bits; | |
25 | be64_t size; | |
26 | be32_t crypt_method; | |
27 | ||
28 | be32_t l1_size; | |
29 | be64_t l1_table_offset; | |
30 | ||
31 | be64_t refcount_table_offset; | |
32 | be32_t refcount_table_clusters; | |
33 | ||
34 | be32_t nb_snapshots; | |
35 | be64_t snapshots_offset; | |
36 | ||
37 | /* The remainder is only present on QCOW3 */ | |
38 | be64_t incompatible_features; | |
39 | be64_t compatible_features; | |
40 | be64_t autoclear_features; | |
41 | ||
42 | be32_t refcount_order; | |
43 | be32_t header_length; | |
44 | } Header; | |
45 | ||
46 | #define HEADER_MAGIC(header) be32toh((header)->magic) | |
47 | #define HEADER_VERSION(header) be32toh((header)->version) | |
48 | #define HEADER_CLUSTER_BITS(header) be32toh((header)->cluster_bits) | |
49 | #define HEADER_CLUSTER_SIZE(header) (1ULL << HEADER_CLUSTER_BITS(header)) | |
50 | #define HEADER_L2_BITS(header) (HEADER_CLUSTER_BITS(header) - 3) | |
51 | #define HEADER_SIZE(header) be64toh((header)->size) | |
52 | #define HEADER_CRYPT_METHOD(header) be32toh((header)->crypt_method) | |
53 | #define HEADER_L1_SIZE(header) be32toh((header)->l1_size) | |
54 | #define HEADER_L2_SIZE(header) (HEADER_CLUSTER_SIZE(header)/sizeof(uint64_t)) | |
55 | #define HEADER_L1_TABLE_OFFSET(header) be64toh((header)->l1_table_offset) | |
56 | ||
57 | static uint32_t HEADER_HEADER_LENGTH(const Header *h) { | |
58 | if (HEADER_VERSION(h) < 3) | |
59 | return offsetof(Header, incompatible_features); | |
60 | ||
61 | return be32toh(h->header_length); | |
62 | } | |
63 | ||
64 | static int copy_cluster( | |
65 | int sfd, uint64_t soffset, | |
66 | int dfd, uint64_t doffset, | |
67 | uint64_t cluster_size, | |
68 | void *buffer) { | |
69 | ||
70 | ssize_t l; | |
1c7dd825 LP |
71 | int r; |
72 | ||
73 | r = btrfs_clone_range(sfd, soffset, dfd, doffset, cluster_size); | |
74 | if (r >= 0) | |
75 | return r; | |
edce2aed LP |
76 | |
77 | l = pread(sfd, buffer, cluster_size, soffset); | |
78 | if (l < 0) | |
79 | return -errno; | |
80 | if ((uint64_t) l != cluster_size) | |
81 | return -EIO; | |
82 | ||
83 | l = pwrite(dfd, buffer, cluster_size, doffset); | |
84 | if (l < 0) | |
85 | return -errno; | |
86 | if ((uint64_t) l != cluster_size) | |
87 | return -EIO; | |
88 | ||
89 | return 0; | |
90 | } | |
91 | ||
92 | static int decompress_cluster( | |
93 | int sfd, uint64_t soffset, | |
94 | int dfd, uint64_t doffset, | |
95 | uint64_t compressed_size, | |
96 | uint64_t cluster_size, | |
97 | void *buffer1, | |
98 | void *buffer2) { | |
99 | ||
100 | _cleanup_free_ void *large_buffer = NULL; | |
101 | z_stream s = {}; | |
102 | uint64_t sz; | |
103 | ssize_t l; | |
104 | int r; | |
105 | ||
106 | if (compressed_size > cluster_size) { | |
107 | /* The usual cluster buffer doesn't suffice, let's | |
108 | * allocate a larger one, temporarily */ | |
109 | ||
110 | large_buffer = malloc(compressed_size); | |
111 | if (!large_buffer) | |
112 | return -ENOMEM; | |
113 | ||
114 | buffer1 = large_buffer; | |
115 | } | |
116 | ||
117 | l = pread(sfd, buffer1, compressed_size, soffset); | |
118 | if (l < 0) | |
119 | return -errno; | |
120 | if ((uint64_t) l != compressed_size) | |
121 | return -EIO; | |
122 | ||
123 | s.next_in = buffer1; | |
124 | s.avail_in = compressed_size; | |
125 | s.next_out = buffer2; | |
126 | s.avail_out = cluster_size; | |
127 | ||
128 | r = inflateInit2(&s, -12); | |
129 | if (r != Z_OK) | |
130 | return -EIO; | |
131 | ||
132 | r = inflate(&s, Z_FINISH); | |
133 | sz = (uint8_t*) s.next_out - (uint8_t*) buffer2; | |
134 | inflateEnd(&s); | |
135 | if (r != Z_STREAM_END || sz != cluster_size) | |
136 | return -EIO; | |
137 | ||
138 | l = pwrite(dfd, buffer2, cluster_size, doffset); | |
139 | if (l < 0) | |
140 | return -errno; | |
141 | if ((uint64_t) l != cluster_size) | |
142 | return -EIO; | |
143 | ||
144 | return 0; | |
145 | } | |
146 | ||
147 | static int normalize_offset( | |
148 | const Header *header, | |
149 | uint64_t p, | |
150 | uint64_t *ret, | |
151 | bool *compressed, | |
152 | uint64_t *compressed_size) { | |
153 | ||
154 | uint64_t q; | |
155 | ||
156 | q = be64toh(p); | |
157 | ||
158 | if (q & QCOW2_COMPRESSED) { | |
159 | uint64_t sz, csize_shift, csize_mask; | |
160 | ||
161 | if (!compressed) | |
15411c0c | 162 | return -EOPNOTSUPP; |
edce2aed LP |
163 | |
164 | csize_shift = 64 - 2 - (HEADER_CLUSTER_BITS(header) - 8); | |
165 | csize_mask = (1ULL << (HEADER_CLUSTER_BITS(header) - 8)) - 1; | |
166 | sz = (((q >> csize_shift) & csize_mask) + 1) * 512 - (q & 511); | |
167 | q &= ((1ULL << csize_shift) - 1); | |
168 | ||
169 | if (compressed_size) | |
170 | *compressed_size = sz; | |
171 | ||
172 | *compressed = true; | |
173 | ||
174 | } else { | |
175 | if (compressed) { | |
176 | *compressed = false; | |
177 | *compressed_size = 0; | |
178 | } | |
179 | ||
180 | if (q & QCOW2_ZERO) { | |
181 | /* We make no distinction between zero blocks and holes */ | |
182 | *ret = 0; | |
183 | return 0; | |
184 | } | |
185 | ||
186 | q &= ~QCOW2_COPIED; | |
187 | } | |
188 | ||
189 | *ret = q; | |
190 | return q > 0; /* returns positive if not a hole */ | |
191 | } | |
192 | ||
193 | static int verify_header(const Header *header) { | |
194 | assert(header); | |
195 | ||
196 | if (HEADER_MAGIC(header) != QCOW2_MAGIC) | |
197 | return -EBADMSG; | |
198 | ||
4c701096 | 199 | if (!IN_SET(HEADER_VERSION(header), 2, 3)) |
15411c0c | 200 | return -EOPNOTSUPP; |
edce2aed LP |
201 | |
202 | if (HEADER_CRYPT_METHOD(header) != 0) | |
15411c0c | 203 | return -EOPNOTSUPP; |
edce2aed LP |
204 | |
205 | if (HEADER_CLUSTER_BITS(header) < 9) /* 512K */ | |
206 | return -EBADMSG; | |
207 | ||
208 | if (HEADER_CLUSTER_BITS(header) > 21) /* 2MB */ | |
209 | return -EBADMSG; | |
210 | ||
211 | if (HEADER_SIZE(header) % HEADER_CLUSTER_SIZE(header) != 0) | |
212 | return -EBADMSG; | |
213 | ||
214 | if (HEADER_L1_SIZE(header) > 32*1024*1024) /* 32MB */ | |
215 | return -EBADMSG; | |
216 | ||
217 | if (HEADER_VERSION(header) == 3) { | |
218 | ||
219 | if (header->incompatible_features != 0) | |
15411c0c | 220 | return -EOPNOTSUPP; |
edce2aed LP |
221 | |
222 | if (HEADER_HEADER_LENGTH(header) < sizeof(Header)) | |
223 | return -EBADMSG; | |
224 | } | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | int qcow2_convert(int qcow2_fd, int raw_fd) { | |
230 | _cleanup_free_ void *buffer1 = NULL, *buffer2 = NULL; | |
231 | _cleanup_free_ be64_t *l1_table = NULL, *l2_table = NULL; | |
232 | uint64_t sz, i; | |
233 | Header header; | |
234 | ssize_t l; | |
235 | int r; | |
236 | ||
237 | l = pread(qcow2_fd, &header, sizeof(header), 0); | |
238 | if (l < 0) | |
239 | return -errno; | |
240 | if (l != sizeof(header)) | |
241 | return -EIO; | |
242 | ||
243 | r = verify_header(&header); | |
244 | if (r < 0) | |
245 | return r; | |
246 | ||
247 | l1_table = new(be64_t, HEADER_L1_SIZE(&header)); | |
248 | if (!l1_table) | |
249 | return -ENOMEM; | |
250 | ||
251 | l2_table = malloc(HEADER_CLUSTER_SIZE(&header)); | |
252 | if (!l2_table) | |
253 | return -ENOMEM; | |
254 | ||
255 | buffer1 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
256 | if (!buffer1) | |
257 | return -ENOMEM; | |
258 | ||
259 | buffer2 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
260 | if (!buffer2) | |
261 | return -ENOMEM; | |
262 | ||
263 | /* Empty the file if it exists, we rely on zero bits */ | |
264 | if (ftruncate(raw_fd, 0) < 0) | |
265 | return -errno; | |
266 | ||
267 | if (ftruncate(raw_fd, HEADER_SIZE(&header)) < 0) | |
268 | return -errno; | |
269 | ||
270 | sz = sizeof(uint64_t) * HEADER_L1_SIZE(&header); | |
271 | l = pread(qcow2_fd, l1_table, sz, HEADER_L1_TABLE_OFFSET(&header)); | |
272 | if (l < 0) | |
273 | return -errno; | |
274 | if ((uint64_t) l != sz) | |
275 | return -EIO; | |
276 | ||
277 | for (i = 0; i < HEADER_L1_SIZE(&header); i ++) { | |
278 | uint64_t l2_begin, j; | |
279 | ||
280 | r = normalize_offset(&header, l1_table[i], &l2_begin, NULL, NULL); | |
281 | if (r < 0) | |
282 | return r; | |
283 | if (r == 0) | |
284 | continue; | |
285 | ||
286 | l = pread(qcow2_fd, l2_table, HEADER_CLUSTER_SIZE(&header), l2_begin); | |
287 | if (l < 0) | |
288 | return -errno; | |
289 | if ((uint64_t) l != HEADER_CLUSTER_SIZE(&header)) | |
290 | return -EIO; | |
291 | ||
292 | for (j = 0; j < HEADER_L2_SIZE(&header); j++) { | |
293 | uint64_t data_begin, p, compressed_size; | |
294 | bool compressed; | |
295 | ||
296 | p = ((i << HEADER_L2_BITS(&header)) + j) << HEADER_CLUSTER_BITS(&header); | |
297 | ||
298 | r = normalize_offset(&header, l2_table[j], &data_begin, &compressed, &compressed_size); | |
299 | if (r < 0) | |
300 | return r; | |
301 | if (r == 0) | |
302 | continue; | |
303 | ||
304 | if (compressed) | |
305 | r = decompress_cluster( | |
306 | qcow2_fd, data_begin, | |
307 | raw_fd, p, | |
308 | compressed_size, HEADER_CLUSTER_SIZE(&header), | |
309 | buffer1, buffer2); | |
310 | else | |
311 | r = copy_cluster( | |
312 | qcow2_fd, data_begin, | |
313 | raw_fd, p, | |
314 | HEADER_CLUSTER_SIZE(&header), buffer1); | |
315 | if (r < 0) | |
316 | return r; | |
317 | } | |
318 | } | |
319 | ||
320 | return 0; | |
321 | } | |
322 | ||
323 | int qcow2_detect(int fd) { | |
324 | be32_t id; | |
325 | ssize_t l; | |
326 | ||
327 | l = pread(fd, &id, sizeof(id), 0); | |
328 | if (l < 0) | |
329 | return -errno; | |
330 | if (l != sizeof(id)) | |
331 | return -EIO; | |
332 | ||
333 | return htobe32(QCOW2_MAGIC) == id; | |
334 | } |