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edce2aed LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2015 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <zlib.h> | |
23 | ||
b5efdb8a | 24 | #include "alloc-util.h" |
1c7dd825 | 25 | #include "btrfs-util.h" |
b5efdb8a LP |
26 | #include "qcow2-util.h" |
27 | #include "sparse-endian.h" | |
28 | #include "util.h" | |
edce2aed LP |
29 | |
30 | #define QCOW2_MAGIC 0x514649fb | |
31 | ||
32 | #define QCOW2_COPIED (1ULL << 63) | |
33 | #define QCOW2_COMPRESSED (1ULL << 62) | |
34 | #define QCOW2_ZERO (1ULL << 0) | |
35 | ||
36 | typedef struct _packed_ Header { | |
37 | be32_t magic; | |
38 | be32_t version; | |
39 | ||
40 | be64_t backing_file_offset; | |
41 | be32_t backing_file_size; | |
42 | ||
43 | be32_t cluster_bits; | |
44 | be64_t size; | |
45 | be32_t crypt_method; | |
46 | ||
47 | be32_t l1_size; | |
48 | be64_t l1_table_offset; | |
49 | ||
50 | be64_t refcount_table_offset; | |
51 | be32_t refcount_table_clusters; | |
52 | ||
53 | be32_t nb_snapshots; | |
54 | be64_t snapshots_offset; | |
55 | ||
56 | /* The remainder is only present on QCOW3 */ | |
57 | be64_t incompatible_features; | |
58 | be64_t compatible_features; | |
59 | be64_t autoclear_features; | |
60 | ||
61 | be32_t refcount_order; | |
62 | be32_t header_length; | |
63 | } Header; | |
64 | ||
65 | #define HEADER_MAGIC(header) be32toh((header)->magic) | |
66 | #define HEADER_VERSION(header) be32toh((header)->version) | |
67 | #define HEADER_CLUSTER_BITS(header) be32toh((header)->cluster_bits) | |
68 | #define HEADER_CLUSTER_SIZE(header) (1ULL << HEADER_CLUSTER_BITS(header)) | |
69 | #define HEADER_L2_BITS(header) (HEADER_CLUSTER_BITS(header) - 3) | |
70 | #define HEADER_SIZE(header) be64toh((header)->size) | |
71 | #define HEADER_CRYPT_METHOD(header) be32toh((header)->crypt_method) | |
72 | #define HEADER_L1_SIZE(header) be32toh((header)->l1_size) | |
73 | #define HEADER_L2_SIZE(header) (HEADER_CLUSTER_SIZE(header)/sizeof(uint64_t)) | |
74 | #define HEADER_L1_TABLE_OFFSET(header) be64toh((header)->l1_table_offset) | |
75 | ||
76 | static uint32_t HEADER_HEADER_LENGTH(const Header *h) { | |
77 | if (HEADER_VERSION(h) < 3) | |
78 | return offsetof(Header, incompatible_features); | |
79 | ||
80 | return be32toh(h->header_length); | |
81 | } | |
82 | ||
83 | static int copy_cluster( | |
84 | int sfd, uint64_t soffset, | |
85 | int dfd, uint64_t doffset, | |
86 | uint64_t cluster_size, | |
87 | void *buffer) { | |
88 | ||
89 | ssize_t l; | |
1c7dd825 LP |
90 | int r; |
91 | ||
92 | r = btrfs_clone_range(sfd, soffset, dfd, doffset, cluster_size); | |
93 | if (r >= 0) | |
94 | return r; | |
edce2aed LP |
95 | |
96 | l = pread(sfd, buffer, cluster_size, soffset); | |
97 | if (l < 0) | |
98 | return -errno; | |
99 | if ((uint64_t) l != cluster_size) | |
100 | return -EIO; | |
101 | ||
102 | l = pwrite(dfd, buffer, cluster_size, doffset); | |
103 | if (l < 0) | |
104 | return -errno; | |
105 | if ((uint64_t) l != cluster_size) | |
106 | return -EIO; | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
111 | static int decompress_cluster( | |
112 | int sfd, uint64_t soffset, | |
113 | int dfd, uint64_t doffset, | |
114 | uint64_t compressed_size, | |
115 | uint64_t cluster_size, | |
116 | void *buffer1, | |
117 | void *buffer2) { | |
118 | ||
119 | _cleanup_free_ void *large_buffer = NULL; | |
120 | z_stream s = {}; | |
121 | uint64_t sz; | |
122 | ssize_t l; | |
123 | int r; | |
124 | ||
125 | if (compressed_size > cluster_size) { | |
126 | /* The usual cluster buffer doesn't suffice, let's | |
127 | * allocate a larger one, temporarily */ | |
128 | ||
129 | large_buffer = malloc(compressed_size); | |
130 | if (!large_buffer) | |
131 | return -ENOMEM; | |
132 | ||
133 | buffer1 = large_buffer; | |
134 | } | |
135 | ||
136 | l = pread(sfd, buffer1, compressed_size, soffset); | |
137 | if (l < 0) | |
138 | return -errno; | |
139 | if ((uint64_t) l != compressed_size) | |
140 | return -EIO; | |
141 | ||
142 | s.next_in = buffer1; | |
143 | s.avail_in = compressed_size; | |
144 | s.next_out = buffer2; | |
145 | s.avail_out = cluster_size; | |
146 | ||
147 | r = inflateInit2(&s, -12); | |
148 | if (r != Z_OK) | |
149 | return -EIO; | |
150 | ||
151 | r = inflate(&s, Z_FINISH); | |
152 | sz = (uint8_t*) s.next_out - (uint8_t*) buffer2; | |
153 | inflateEnd(&s); | |
154 | if (r != Z_STREAM_END || sz != cluster_size) | |
155 | return -EIO; | |
156 | ||
157 | l = pwrite(dfd, buffer2, cluster_size, doffset); | |
158 | if (l < 0) | |
159 | return -errno; | |
160 | if ((uint64_t) l != cluster_size) | |
161 | return -EIO; | |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
166 | static int normalize_offset( | |
167 | const Header *header, | |
168 | uint64_t p, | |
169 | uint64_t *ret, | |
170 | bool *compressed, | |
171 | uint64_t *compressed_size) { | |
172 | ||
173 | uint64_t q; | |
174 | ||
175 | q = be64toh(p); | |
176 | ||
177 | if (q & QCOW2_COMPRESSED) { | |
178 | uint64_t sz, csize_shift, csize_mask; | |
179 | ||
180 | if (!compressed) | |
15411c0c | 181 | return -EOPNOTSUPP; |
edce2aed LP |
182 | |
183 | csize_shift = 64 - 2 - (HEADER_CLUSTER_BITS(header) - 8); | |
184 | csize_mask = (1ULL << (HEADER_CLUSTER_BITS(header) - 8)) - 1; | |
185 | sz = (((q >> csize_shift) & csize_mask) + 1) * 512 - (q & 511); | |
186 | q &= ((1ULL << csize_shift) - 1); | |
187 | ||
188 | if (compressed_size) | |
189 | *compressed_size = sz; | |
190 | ||
191 | *compressed = true; | |
192 | ||
193 | } else { | |
194 | if (compressed) { | |
195 | *compressed = false; | |
196 | *compressed_size = 0; | |
197 | } | |
198 | ||
199 | if (q & QCOW2_ZERO) { | |
200 | /* We make no distinction between zero blocks and holes */ | |
201 | *ret = 0; | |
202 | return 0; | |
203 | } | |
204 | ||
205 | q &= ~QCOW2_COPIED; | |
206 | } | |
207 | ||
208 | *ret = q; | |
209 | return q > 0; /* returns positive if not a hole */ | |
210 | } | |
211 | ||
212 | static int verify_header(const Header *header) { | |
213 | assert(header); | |
214 | ||
215 | if (HEADER_MAGIC(header) != QCOW2_MAGIC) | |
216 | return -EBADMSG; | |
217 | ||
218 | if (HEADER_VERSION(header) != 2 && | |
219 | HEADER_VERSION(header) != 3) | |
15411c0c | 220 | return -EOPNOTSUPP; |
edce2aed LP |
221 | |
222 | if (HEADER_CRYPT_METHOD(header) != 0) | |
15411c0c | 223 | return -EOPNOTSUPP; |
edce2aed LP |
224 | |
225 | if (HEADER_CLUSTER_BITS(header) < 9) /* 512K */ | |
226 | return -EBADMSG; | |
227 | ||
228 | if (HEADER_CLUSTER_BITS(header) > 21) /* 2MB */ | |
229 | return -EBADMSG; | |
230 | ||
231 | if (HEADER_SIZE(header) % HEADER_CLUSTER_SIZE(header) != 0) | |
232 | return -EBADMSG; | |
233 | ||
234 | if (HEADER_L1_SIZE(header) > 32*1024*1024) /* 32MB */ | |
235 | return -EBADMSG; | |
236 | ||
237 | if (HEADER_VERSION(header) == 3) { | |
238 | ||
239 | if (header->incompatible_features != 0) | |
15411c0c | 240 | return -EOPNOTSUPP; |
edce2aed LP |
241 | |
242 | if (HEADER_HEADER_LENGTH(header) < sizeof(Header)) | |
243 | return -EBADMSG; | |
244 | } | |
245 | ||
246 | return 0; | |
247 | } | |
248 | ||
249 | int qcow2_convert(int qcow2_fd, int raw_fd) { | |
250 | _cleanup_free_ void *buffer1 = NULL, *buffer2 = NULL; | |
251 | _cleanup_free_ be64_t *l1_table = NULL, *l2_table = NULL; | |
252 | uint64_t sz, i; | |
253 | Header header; | |
254 | ssize_t l; | |
255 | int r; | |
256 | ||
257 | l = pread(qcow2_fd, &header, sizeof(header), 0); | |
258 | if (l < 0) | |
259 | return -errno; | |
260 | if (l != sizeof(header)) | |
261 | return -EIO; | |
262 | ||
263 | r = verify_header(&header); | |
264 | if (r < 0) | |
265 | return r; | |
266 | ||
267 | l1_table = new(be64_t, HEADER_L1_SIZE(&header)); | |
268 | if (!l1_table) | |
269 | return -ENOMEM; | |
270 | ||
271 | l2_table = malloc(HEADER_CLUSTER_SIZE(&header)); | |
272 | if (!l2_table) | |
273 | return -ENOMEM; | |
274 | ||
275 | buffer1 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
276 | if (!buffer1) | |
277 | return -ENOMEM; | |
278 | ||
279 | buffer2 = malloc(HEADER_CLUSTER_SIZE(&header)); | |
280 | if (!buffer2) | |
281 | return -ENOMEM; | |
282 | ||
283 | /* Empty the file if it exists, we rely on zero bits */ | |
284 | if (ftruncate(raw_fd, 0) < 0) | |
285 | return -errno; | |
286 | ||
287 | if (ftruncate(raw_fd, HEADER_SIZE(&header)) < 0) | |
288 | return -errno; | |
289 | ||
290 | sz = sizeof(uint64_t) * HEADER_L1_SIZE(&header); | |
291 | l = pread(qcow2_fd, l1_table, sz, HEADER_L1_TABLE_OFFSET(&header)); | |
292 | if (l < 0) | |
293 | return -errno; | |
294 | if ((uint64_t) l != sz) | |
295 | return -EIO; | |
296 | ||
297 | for (i = 0; i < HEADER_L1_SIZE(&header); i ++) { | |
298 | uint64_t l2_begin, j; | |
299 | ||
300 | r = normalize_offset(&header, l1_table[i], &l2_begin, NULL, NULL); | |
301 | if (r < 0) | |
302 | return r; | |
303 | if (r == 0) | |
304 | continue; | |
305 | ||
306 | l = pread(qcow2_fd, l2_table, HEADER_CLUSTER_SIZE(&header), l2_begin); | |
307 | if (l < 0) | |
308 | return -errno; | |
309 | if ((uint64_t) l != HEADER_CLUSTER_SIZE(&header)) | |
310 | return -EIO; | |
311 | ||
312 | for (j = 0; j < HEADER_L2_SIZE(&header); j++) { | |
313 | uint64_t data_begin, p, compressed_size; | |
314 | bool compressed; | |
315 | ||
316 | p = ((i << HEADER_L2_BITS(&header)) + j) << HEADER_CLUSTER_BITS(&header); | |
317 | ||
318 | r = normalize_offset(&header, l2_table[j], &data_begin, &compressed, &compressed_size); | |
319 | if (r < 0) | |
320 | return r; | |
321 | if (r == 0) | |
322 | continue; | |
323 | ||
324 | if (compressed) | |
325 | r = decompress_cluster( | |
326 | qcow2_fd, data_begin, | |
327 | raw_fd, p, | |
328 | compressed_size, HEADER_CLUSTER_SIZE(&header), | |
329 | buffer1, buffer2); | |
330 | else | |
331 | r = copy_cluster( | |
332 | qcow2_fd, data_begin, | |
333 | raw_fd, p, | |
334 | HEADER_CLUSTER_SIZE(&header), buffer1); | |
335 | if (r < 0) | |
336 | return r; | |
337 | } | |
338 | } | |
339 | ||
340 | return 0; | |
341 | } | |
342 | ||
343 | int qcow2_detect(int fd) { | |
344 | be32_t id; | |
345 | ssize_t l; | |
346 | ||
347 | l = pread(fd, &id, sizeof(id), 0); | |
348 | if (l < 0) | |
349 | return -errno; | |
350 | if (l != sizeof(id)) | |
351 | return -EIO; | |
352 | ||
353 | return htobe32(QCOW2_MAGIC) == id; | |
354 | } |