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edce2aed LP |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2015 Lennart Poettering | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
18 | ***/ | |
19 | ||
20 | #include <zlib.h> | |
21 | ||
b5efdb8a | 22 | #include "alloc-util.h" |
1c7dd825 | 23 | #include "btrfs-util.h" |
b5efdb8a LP |
24 | #include "qcow2-util.h" |
25 | #include "sparse-endian.h" | |
26 | #include "util.h" | |
edce2aed LP |
27 | |
28 | #define QCOW2_MAGIC 0x514649fb | |
29 | ||
30 | #define QCOW2_COPIED (1ULL << 63) | |
31 | #define QCOW2_COMPRESSED (1ULL << 62) | |
32 | #define QCOW2_ZERO (1ULL << 0) | |
33 | ||
34 | typedef struct _packed_ Header { | |
35 | be32_t magic; | |
36 | be32_t version; | |
37 | ||
38 | be64_t backing_file_offset; | |
39 | be32_t backing_file_size; | |
40 | ||
41 | be32_t cluster_bits; | |
42 | be64_t size; | |
43 | be32_t crypt_method; | |
44 | ||
45 | be32_t l1_size; | |
46 | be64_t l1_table_offset; | |
47 | ||
48 | be64_t refcount_table_offset; | |
49 | be32_t refcount_table_clusters; | |
50 | ||
51 | be32_t nb_snapshots; | |
52 | be64_t snapshots_offset; | |
53 | ||
54 | /* The remainder is only present on QCOW3 */ | |
55 | be64_t incompatible_features; | |
56 | be64_t compatible_features; | |
57 | be64_t autoclear_features; | |
58 | ||
59 | be32_t refcount_order; | |
60 | be32_t header_length; | |
61 | } Header; | |
62 | ||
63 | #define HEADER_MAGIC(header) be32toh((header)->magic) | |
64 | #define HEADER_VERSION(header) be32toh((header)->version) | |
65 | #define HEADER_CLUSTER_BITS(header) be32toh((header)->cluster_bits) | |
66 | #define HEADER_CLUSTER_SIZE(header) (1ULL << HEADER_CLUSTER_BITS(header)) | |
67 | #define HEADER_L2_BITS(header) (HEADER_CLUSTER_BITS(header) - 3) | |
68 | #define HEADER_SIZE(header) be64toh((header)->size) | |
69 | #define HEADER_CRYPT_METHOD(header) be32toh((header)->crypt_method) | |
70 | #define HEADER_L1_SIZE(header) be32toh((header)->l1_size) | |
71 | #define HEADER_L2_SIZE(header) (HEADER_CLUSTER_SIZE(header)/sizeof(uint64_t)) | |
72 | #define HEADER_L1_TABLE_OFFSET(header) be64toh((header)->l1_table_offset) | |
73 | ||
74 | static uint32_t HEADER_HEADER_LENGTH(const Header *h) { | |
75 | if (HEADER_VERSION(h) < 3) | |
76 | return offsetof(Header, incompatible_features); | |
77 | ||
78 | return be32toh(h->header_length); | |
79 | } | |
80 | ||
81 | static int copy_cluster( | |
82 | int sfd, uint64_t soffset, | |
83 | int dfd, uint64_t doffset, | |
84 | uint64_t cluster_size, | |
85 | void *buffer) { | |
86 | ||
87 | ssize_t l; | |
1c7dd825 LP |
88 | int r; |
89 | ||
90 | r = btrfs_clone_range(sfd, soffset, dfd, doffset, cluster_size); | |
91 | if (r >= 0) | |
92 | return r; | |
edce2aed LP |
93 | |
94 | l = pread(sfd, buffer, cluster_size, soffset); | |
95 | if (l < 0) | |
96 | return -errno; | |
97 | if ((uint64_t) l != cluster_size) | |
98 | return -EIO; | |
99 | ||
100 | l = pwrite(dfd, buffer, cluster_size, doffset); | |
101 | if (l < 0) | |
102 | return -errno; | |
103 | if ((uint64_t) l != cluster_size) | |
104 | return -EIO; | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | static int decompress_cluster( | |
110 | int sfd, uint64_t soffset, | |
111 | int dfd, uint64_t doffset, | |
112 | uint64_t compressed_size, | |
113 | uint64_t cluster_size, | |
114 | void *buffer1, | |
115 | void *buffer2) { | |
116 | ||
117 | _cleanup_free_ void *large_buffer = NULL; | |
118 | z_stream s = {}; | |
119 | uint64_t sz; | |
120 | ssize_t l; | |
121 | int r; | |
122 | ||
123 | if (compressed_size > cluster_size) { | |
124 | /* The usual cluster buffer doesn't suffice, let's | |
125 | * allocate a larger one, temporarily */ | |
126 | ||
127 | large_buffer = malloc(compressed_size); | |
128 | if (!large_buffer) | |
129 | return -ENOMEM; | |
130 | ||
131 | buffer1 = large_buffer; | |
132 | } | |
133 | ||
134 | l = pread(sfd, buffer1, compressed_size, soffset); | |
135 | if (l < 0) | |
136 | return -errno; | |
137 | if ((uint64_t) l != compressed_size) | |
138 | return -EIO; | |
139 | ||
140 | s.next_in = buffer1; | |
141 | s.avail_in = compressed_size; | |
142 | s.next_out = buffer2; | |
143 | s.avail_out = cluster_size; | |
144 | ||
145 | r = inflateInit2(&s, -12); | |
146 | if (r != Z_OK) | |
147 | return -EIO; | |
148 | ||
149 | r = inflate(&s, Z_FINISH); | |
150 | sz = (uint8_t*) s.next_out - (uint8_t*) buffer2; | |
151 | inflateEnd(&s); | |
152 | if (r != Z_STREAM_END || sz != cluster_size) | |
153 | return -EIO; | |
154 | ||
155 | l = pwrite(dfd, buffer2, cluster_size, doffset); | |
156 | if (l < 0) | |
157 | return -errno; | |
158 | if ((uint64_t) l != cluster_size) | |
159 | return -EIO; | |
160 | ||
161 | return 0; | |
162 | } | |
163 | ||
164 | static int normalize_offset( | |
165 | const Header *header, | |
166 | uint64_t p, | |
167 | uint64_t *ret, | |
168 | bool *compressed, | |
169 | uint64_t *compressed_size) { | |
170 | ||
171 | uint64_t q; | |
172 | ||
173 | q = be64toh(p); | |
174 | ||
175 | if (q & QCOW2_COMPRESSED) { | |
176 | uint64_t sz, csize_shift, csize_mask; | |
177 | ||
178 | if (!compressed) | |
15411c0c | 179 | return -EOPNOTSUPP; |
edce2aed LP |
180 | |
181 | csize_shift = 64 - 2 - (HEADER_CLUSTER_BITS(header) - 8); | |
182 | csize_mask = (1ULL << (HEADER_CLUSTER_BITS(header) - 8)) - 1; | |
183 | sz = (((q >> csize_shift) & csize_mask) + 1) * 512 - (q & 511); | |
184 | q &= ((1ULL << csize_shift) - 1); | |
185 | ||
186 | if (compressed_size) | |
187 | *compressed_size = sz; | |
188 | ||
189 | *compressed = true; | |
190 | ||
191 | } else { | |
192 | if (compressed) { | |
193 | *compressed = false; | |
194 | *compressed_size = 0; | |
195 | } | |
196 | ||
197 | if (q & QCOW2_ZERO) { | |
198 | /* We make no distinction between zero blocks and holes */ | |
199 | *ret = 0; | |
200 | return 0; | |
201 | } | |
202 | ||
203 | q &= ~QCOW2_COPIED; | |
204 | } | |
205 | ||
206 | *ret = q; | |
207 | return q > 0; /* returns positive if not a hole */ | |
208 | } | |
209 | ||
210 | static int verify_header(const Header *header) { | |
211 | assert(header); | |
212 | ||
213 | if (HEADER_MAGIC(header) != QCOW2_MAGIC) | |
214 | return -EBADMSG; | |
215 | ||
216 | if (HEADER_VERSION(header) != 2 && | |
217 | HEADER_VERSION(header) != 3) | |
15411c0c | 218 | return -EOPNOTSUPP; |
edce2aed LP |
219 | |
220 | if (HEADER_CRYPT_METHOD(header) != 0) | |
15411c0c | 221 | return -EOPNOTSUPP; |
edce2aed LP |
222 | |
223 | if (HEADER_CLUSTER_BITS(header) < 9) /* 512K */ | |
224 | return -EBADMSG; | |
225 | ||
226 | if (HEADER_CLUSTER_BITS(header) > 21) /* 2MB */ | |
227 | return -EBADMSG; | |
228 | ||
229 | if (HEADER_SIZE(header) % HEADER_CLUSTER_SIZE(header) != 0) | |
230 | return -EBADMSG; | |
231 | ||
232 | if (HEADER_L1_SIZE(header) > 32*1024*1024) /* 32MB */ | |
233 | return -EBADMSG; | |
234 | ||
235 | if (HEADER_VERSION(header) == 3) { | |
236 | ||
237 | if (header->incompatible_features != 0) | |
15411c0c | 238 | return -EOPNOTSUPP; |
edce2aed LP |
239 | |
240 | if (HEADER_HEADER_LENGTH(header) < sizeof(Header)) | |
241 | return -EBADMSG; | |
242 | } | |
243 | ||
244 | return 0; | |
245 | } | |
246 | ||
247 | int qcow2_convert(int qcow2_fd, int raw_fd) { | |
248 | _cleanup_free_ void *buffer1 = NULL, *buffer2 = NULL; | |
249 | _cleanup_free_ be64_t *l1_table = NULL, *l2_table = NULL; | |
250 | uint64_t sz, i; | |
251 | Header header; | |
252 | ssize_t l; | |
253 | int r; | |
254 | ||
255 | l = pread(qcow2_fd, &header, sizeof(header), 0); | |
256 | if (l < 0) | |
257 | return -errno; | |
258 | if (l != sizeof(header)) | |
259 | return -EIO; | |
260 | ||
261 | r = verify_header(&header); | |
262 | if (r < 0) | |
263 | return r; | |
264 | ||
265 | l1_table = new(be64_t, HEADER_L1_SIZE(&header)); | |
266 | if (!l1_table) | |
267 | return -ENOMEM; | |
268 | ||
269 | l2_table = malloc(HEADER_CLUSTER_SIZE(&header)); | |
270 | if (!l2_table) | |
271 | return -ENOMEM; | |
272 | ||
273 | buffer1 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
274 | if (!buffer1) | |
275 | return -ENOMEM; | |
276 | ||
277 | buffer2 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
278 | if (!buffer2) | |
279 | return -ENOMEM; | |
280 | ||
281 | /* Empty the file if it exists, we rely on zero bits */ | |
282 | if (ftruncate(raw_fd, 0) < 0) | |
283 | return -errno; | |
284 | ||
285 | if (ftruncate(raw_fd, HEADER_SIZE(&header)) < 0) | |
286 | return -errno; | |
287 | ||
288 | sz = sizeof(uint64_t) * HEADER_L1_SIZE(&header); | |
289 | l = pread(qcow2_fd, l1_table, sz, HEADER_L1_TABLE_OFFSET(&header)); | |
290 | if (l < 0) | |
291 | return -errno; | |
292 | if ((uint64_t) l != sz) | |
293 | return -EIO; | |
294 | ||
295 | for (i = 0; i < HEADER_L1_SIZE(&header); i ++) { | |
296 | uint64_t l2_begin, j; | |
297 | ||
298 | r = normalize_offset(&header, l1_table[i], &l2_begin, NULL, NULL); | |
299 | if (r < 0) | |
300 | return r; | |
301 | if (r == 0) | |
302 | continue; | |
303 | ||
304 | l = pread(qcow2_fd, l2_table, HEADER_CLUSTER_SIZE(&header), l2_begin); | |
305 | if (l < 0) | |
306 | return -errno; | |
307 | if ((uint64_t) l != HEADER_CLUSTER_SIZE(&header)) | |
308 | return -EIO; | |
309 | ||
310 | for (j = 0; j < HEADER_L2_SIZE(&header); j++) { | |
311 | uint64_t data_begin, p, compressed_size; | |
312 | bool compressed; | |
313 | ||
314 | p = ((i << HEADER_L2_BITS(&header)) + j) << HEADER_CLUSTER_BITS(&header); | |
315 | ||
316 | r = normalize_offset(&header, l2_table[j], &data_begin, &compressed, &compressed_size); | |
317 | if (r < 0) | |
318 | return r; | |
319 | if (r == 0) | |
320 | continue; | |
321 | ||
322 | if (compressed) | |
323 | r = decompress_cluster( | |
324 | qcow2_fd, data_begin, | |
325 | raw_fd, p, | |
326 | compressed_size, HEADER_CLUSTER_SIZE(&header), | |
327 | buffer1, buffer2); | |
328 | else | |
329 | r = copy_cluster( | |
330 | qcow2_fd, data_begin, | |
331 | raw_fd, p, | |
332 | HEADER_CLUSTER_SIZE(&header), buffer1); | |
333 | if (r < 0) | |
334 | return r; | |
335 | } | |
336 | } | |
337 | ||
338 | return 0; | |
339 | } | |
340 | ||
341 | int qcow2_detect(int fd) { | |
342 | be32_t id; | |
343 | ssize_t l; | |
344 | ||
345 | l = pread(fd, &id, sizeof(id), 0); | |
346 | if (l < 0) | |
347 | return -errno; | |
348 | if (l != sizeof(id)) | |
349 | return -EIO; | |
350 | ||
351 | return htobe32(QCOW2_MAGIC) == id; | |
352 | } |