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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
edce2aed | 2 | /*** |
edce2aed | 3 | Copyright 2015 Lennart Poettering |
edce2aed LP |
4 | ***/ |
5 | ||
6 | #include <zlib.h> | |
7 | ||
b5efdb8a | 8 | #include "alloc-util.h" |
1c7dd825 | 9 | #include "btrfs-util.h" |
b5efdb8a LP |
10 | #include "qcow2-util.h" |
11 | #include "sparse-endian.h" | |
12 | #include "util.h" | |
edce2aed LP |
13 | |
14 | #define QCOW2_MAGIC 0x514649fb | |
15 | ||
16 | #define QCOW2_COPIED (1ULL << 63) | |
17 | #define QCOW2_COMPRESSED (1ULL << 62) | |
18 | #define QCOW2_ZERO (1ULL << 0) | |
19 | ||
20 | typedef struct _packed_ Header { | |
21 | be32_t magic; | |
22 | be32_t version; | |
23 | ||
24 | be64_t backing_file_offset; | |
25 | be32_t backing_file_size; | |
26 | ||
27 | be32_t cluster_bits; | |
28 | be64_t size; | |
29 | be32_t crypt_method; | |
30 | ||
31 | be32_t l1_size; | |
32 | be64_t l1_table_offset; | |
33 | ||
34 | be64_t refcount_table_offset; | |
35 | be32_t refcount_table_clusters; | |
36 | ||
37 | be32_t nb_snapshots; | |
38 | be64_t snapshots_offset; | |
39 | ||
40 | /* The remainder is only present on QCOW3 */ | |
41 | be64_t incompatible_features; | |
42 | be64_t compatible_features; | |
43 | be64_t autoclear_features; | |
44 | ||
45 | be32_t refcount_order; | |
46 | be32_t header_length; | |
47 | } Header; | |
48 | ||
49 | #define HEADER_MAGIC(header) be32toh((header)->magic) | |
50 | #define HEADER_VERSION(header) be32toh((header)->version) | |
51 | #define HEADER_CLUSTER_BITS(header) be32toh((header)->cluster_bits) | |
52 | #define HEADER_CLUSTER_SIZE(header) (1ULL << HEADER_CLUSTER_BITS(header)) | |
53 | #define HEADER_L2_BITS(header) (HEADER_CLUSTER_BITS(header) - 3) | |
54 | #define HEADER_SIZE(header) be64toh((header)->size) | |
55 | #define HEADER_CRYPT_METHOD(header) be32toh((header)->crypt_method) | |
56 | #define HEADER_L1_SIZE(header) be32toh((header)->l1_size) | |
57 | #define HEADER_L2_SIZE(header) (HEADER_CLUSTER_SIZE(header)/sizeof(uint64_t)) | |
58 | #define HEADER_L1_TABLE_OFFSET(header) be64toh((header)->l1_table_offset) | |
59 | ||
60 | static uint32_t HEADER_HEADER_LENGTH(const Header *h) { | |
61 | if (HEADER_VERSION(h) < 3) | |
62 | return offsetof(Header, incompatible_features); | |
63 | ||
64 | return be32toh(h->header_length); | |
65 | } | |
66 | ||
67 | static int copy_cluster( | |
68 | int sfd, uint64_t soffset, | |
69 | int dfd, uint64_t doffset, | |
70 | uint64_t cluster_size, | |
71 | void *buffer) { | |
72 | ||
73 | ssize_t l; | |
1c7dd825 LP |
74 | int r; |
75 | ||
76 | r = btrfs_clone_range(sfd, soffset, dfd, doffset, cluster_size); | |
77 | if (r >= 0) | |
78 | return r; | |
edce2aed LP |
79 | |
80 | l = pread(sfd, buffer, cluster_size, soffset); | |
81 | if (l < 0) | |
82 | return -errno; | |
83 | if ((uint64_t) l != cluster_size) | |
84 | return -EIO; | |
85 | ||
86 | l = pwrite(dfd, buffer, cluster_size, doffset); | |
87 | if (l < 0) | |
88 | return -errno; | |
89 | if ((uint64_t) l != cluster_size) | |
90 | return -EIO; | |
91 | ||
92 | return 0; | |
93 | } | |
94 | ||
95 | static int decompress_cluster( | |
96 | int sfd, uint64_t soffset, | |
97 | int dfd, uint64_t doffset, | |
98 | uint64_t compressed_size, | |
99 | uint64_t cluster_size, | |
100 | void *buffer1, | |
101 | void *buffer2) { | |
102 | ||
103 | _cleanup_free_ void *large_buffer = NULL; | |
104 | z_stream s = {}; | |
105 | uint64_t sz; | |
106 | ssize_t l; | |
107 | int r; | |
108 | ||
109 | if (compressed_size > cluster_size) { | |
110 | /* The usual cluster buffer doesn't suffice, let's | |
111 | * allocate a larger one, temporarily */ | |
112 | ||
113 | large_buffer = malloc(compressed_size); | |
114 | if (!large_buffer) | |
115 | return -ENOMEM; | |
116 | ||
117 | buffer1 = large_buffer; | |
118 | } | |
119 | ||
120 | l = pread(sfd, buffer1, compressed_size, soffset); | |
121 | if (l < 0) | |
122 | return -errno; | |
123 | if ((uint64_t) l != compressed_size) | |
124 | return -EIO; | |
125 | ||
126 | s.next_in = buffer1; | |
127 | s.avail_in = compressed_size; | |
128 | s.next_out = buffer2; | |
129 | s.avail_out = cluster_size; | |
130 | ||
131 | r = inflateInit2(&s, -12); | |
132 | if (r != Z_OK) | |
133 | return -EIO; | |
134 | ||
135 | r = inflate(&s, Z_FINISH); | |
136 | sz = (uint8_t*) s.next_out - (uint8_t*) buffer2; | |
137 | inflateEnd(&s); | |
138 | if (r != Z_STREAM_END || sz != cluster_size) | |
139 | return -EIO; | |
140 | ||
141 | l = pwrite(dfd, buffer2, cluster_size, doffset); | |
142 | if (l < 0) | |
143 | return -errno; | |
144 | if ((uint64_t) l != cluster_size) | |
145 | return -EIO; | |
146 | ||
147 | return 0; | |
148 | } | |
149 | ||
150 | static int normalize_offset( | |
151 | const Header *header, | |
152 | uint64_t p, | |
153 | uint64_t *ret, | |
154 | bool *compressed, | |
155 | uint64_t *compressed_size) { | |
156 | ||
157 | uint64_t q; | |
158 | ||
159 | q = be64toh(p); | |
160 | ||
161 | if (q & QCOW2_COMPRESSED) { | |
162 | uint64_t sz, csize_shift, csize_mask; | |
163 | ||
164 | if (!compressed) | |
15411c0c | 165 | return -EOPNOTSUPP; |
edce2aed LP |
166 | |
167 | csize_shift = 64 - 2 - (HEADER_CLUSTER_BITS(header) - 8); | |
168 | csize_mask = (1ULL << (HEADER_CLUSTER_BITS(header) - 8)) - 1; | |
169 | sz = (((q >> csize_shift) & csize_mask) + 1) * 512 - (q & 511); | |
170 | q &= ((1ULL << csize_shift) - 1); | |
171 | ||
172 | if (compressed_size) | |
173 | *compressed_size = sz; | |
174 | ||
175 | *compressed = true; | |
176 | ||
177 | } else { | |
178 | if (compressed) { | |
179 | *compressed = false; | |
180 | *compressed_size = 0; | |
181 | } | |
182 | ||
183 | if (q & QCOW2_ZERO) { | |
184 | /* We make no distinction between zero blocks and holes */ | |
185 | *ret = 0; | |
186 | return 0; | |
187 | } | |
188 | ||
189 | q &= ~QCOW2_COPIED; | |
190 | } | |
191 | ||
192 | *ret = q; | |
193 | return q > 0; /* returns positive if not a hole */ | |
194 | } | |
195 | ||
196 | static int verify_header(const Header *header) { | |
197 | assert(header); | |
198 | ||
199 | if (HEADER_MAGIC(header) != QCOW2_MAGIC) | |
200 | return -EBADMSG; | |
201 | ||
4c701096 | 202 | if (!IN_SET(HEADER_VERSION(header), 2, 3)) |
15411c0c | 203 | return -EOPNOTSUPP; |
edce2aed LP |
204 | |
205 | if (HEADER_CRYPT_METHOD(header) != 0) | |
15411c0c | 206 | return -EOPNOTSUPP; |
edce2aed LP |
207 | |
208 | if (HEADER_CLUSTER_BITS(header) < 9) /* 512K */ | |
209 | return -EBADMSG; | |
210 | ||
211 | if (HEADER_CLUSTER_BITS(header) > 21) /* 2MB */ | |
212 | return -EBADMSG; | |
213 | ||
214 | if (HEADER_SIZE(header) % HEADER_CLUSTER_SIZE(header) != 0) | |
215 | return -EBADMSG; | |
216 | ||
217 | if (HEADER_L1_SIZE(header) > 32*1024*1024) /* 32MB */ | |
218 | return -EBADMSG; | |
219 | ||
220 | if (HEADER_VERSION(header) == 3) { | |
221 | ||
222 | if (header->incompatible_features != 0) | |
15411c0c | 223 | return -EOPNOTSUPP; |
edce2aed LP |
224 | |
225 | if (HEADER_HEADER_LENGTH(header) < sizeof(Header)) | |
226 | return -EBADMSG; | |
227 | } | |
228 | ||
229 | return 0; | |
230 | } | |
231 | ||
232 | int qcow2_convert(int qcow2_fd, int raw_fd) { | |
233 | _cleanup_free_ void *buffer1 = NULL, *buffer2 = NULL; | |
234 | _cleanup_free_ be64_t *l1_table = NULL, *l2_table = NULL; | |
235 | uint64_t sz, i; | |
236 | Header header; | |
237 | ssize_t l; | |
238 | int r; | |
239 | ||
240 | l = pread(qcow2_fd, &header, sizeof(header), 0); | |
241 | if (l < 0) | |
242 | return -errno; | |
243 | if (l != sizeof(header)) | |
244 | return -EIO; | |
245 | ||
246 | r = verify_header(&header); | |
247 | if (r < 0) | |
248 | return r; | |
249 | ||
250 | l1_table = new(be64_t, HEADER_L1_SIZE(&header)); | |
251 | if (!l1_table) | |
252 | return -ENOMEM; | |
253 | ||
254 | l2_table = malloc(HEADER_CLUSTER_SIZE(&header)); | |
255 | if (!l2_table) | |
256 | return -ENOMEM; | |
257 | ||
258 | buffer1 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
259 | if (!buffer1) | |
260 | return -ENOMEM; | |
261 | ||
262 | buffer2 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
263 | if (!buffer2) | |
264 | return -ENOMEM; | |
265 | ||
266 | /* Empty the file if it exists, we rely on zero bits */ | |
267 | if (ftruncate(raw_fd, 0) < 0) | |
268 | return -errno; | |
269 | ||
270 | if (ftruncate(raw_fd, HEADER_SIZE(&header)) < 0) | |
271 | return -errno; | |
272 | ||
273 | sz = sizeof(uint64_t) * HEADER_L1_SIZE(&header); | |
274 | l = pread(qcow2_fd, l1_table, sz, HEADER_L1_TABLE_OFFSET(&header)); | |
275 | if (l < 0) | |
276 | return -errno; | |
277 | if ((uint64_t) l != sz) | |
278 | return -EIO; | |
279 | ||
280 | for (i = 0; i < HEADER_L1_SIZE(&header); i ++) { | |
281 | uint64_t l2_begin, j; | |
282 | ||
283 | r = normalize_offset(&header, l1_table[i], &l2_begin, NULL, NULL); | |
284 | if (r < 0) | |
285 | return r; | |
286 | if (r == 0) | |
287 | continue; | |
288 | ||
289 | l = pread(qcow2_fd, l2_table, HEADER_CLUSTER_SIZE(&header), l2_begin); | |
290 | if (l < 0) | |
291 | return -errno; | |
292 | if ((uint64_t) l != HEADER_CLUSTER_SIZE(&header)) | |
293 | return -EIO; | |
294 | ||
295 | for (j = 0; j < HEADER_L2_SIZE(&header); j++) { | |
296 | uint64_t data_begin, p, compressed_size; | |
297 | bool compressed; | |
298 | ||
299 | p = ((i << HEADER_L2_BITS(&header)) + j) << HEADER_CLUSTER_BITS(&header); | |
300 | ||
301 | r = normalize_offset(&header, l2_table[j], &data_begin, &compressed, &compressed_size); | |
302 | if (r < 0) | |
303 | return r; | |
304 | if (r == 0) | |
305 | continue; | |
306 | ||
307 | if (compressed) | |
308 | r = decompress_cluster( | |
309 | qcow2_fd, data_begin, | |
310 | raw_fd, p, | |
311 | compressed_size, HEADER_CLUSTER_SIZE(&header), | |
312 | buffer1, buffer2); | |
313 | else | |
314 | r = copy_cluster( | |
315 | qcow2_fd, data_begin, | |
316 | raw_fd, p, | |
317 | HEADER_CLUSTER_SIZE(&header), buffer1); | |
318 | if (r < 0) | |
319 | return r; | |
320 | } | |
321 | } | |
322 | ||
323 | return 0; | |
324 | } | |
325 | ||
326 | int qcow2_detect(int fd) { | |
327 | be32_t id; | |
328 | ssize_t l; | |
329 | ||
330 | l = pread(fd, &id, sizeof(id), 0); | |
331 | if (l < 0) | |
332 | return -errno; | |
333 | if (l != sizeof(id)) | |
334 | return -EIO; | |
335 | ||
336 | return htobe32(QCOW2_MAGIC) == id; | |
337 | } |