1 | /* |
2 | * QEMU Block driver for CLOOP images |
3 | * |
4 | * Copyright (c) 2004 Johannes E. Schindelin |
5 | * |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
7 | * of this software and associated documentation files (the "Software"), to deal |
8 | * in the Software without restriction, including without limitation the rights |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
10 | * copies of the Software, and to permit persons to whom the Software is |
11 | * furnished to do so, subject to the following conditions: |
12 | * |
13 | * The above copyright notice and this permission notice shall be included in |
14 | * all copies or substantial portions of the Software. |
15 | * |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
22 | * THE SOFTWARE. |
23 | */ |
24 | #include "qemu/osdep.h" |
25 | #include "qapi/error.h" |
26 | #include "qemu/error-report.h" |
27 | #include "block/block_int.h" |
28 | #include "qemu/module.h" |
29 | #include "qemu/bswap.h" |
30 | #include <zlib.h> |
31 | |
32 | /* Maximum compressed block size */ |
33 | #define MAX_BLOCK_SIZE (64 * 1024 * 1024) |
34 | |
35 | typedef struct BDRVCloopState { |
36 | CoMutex lock; |
37 | uint32_t block_size; |
38 | uint32_t n_blocks; |
39 | uint64_t *offsets; |
40 | uint32_t sectors_per_block; |
41 | uint32_t current_block; |
42 | uint8_t *compressed_block; |
43 | uint8_t *uncompressed_block; |
44 | z_stream zstream; |
45 | } BDRVCloopState; |
46 | |
47 | static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename) |
48 | { |
49 | const char *magic_version_2_0 = "#!/bin/sh\n" |
50 | "#V2.0 Format\n" |
51 | "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n" ; |
52 | int length = strlen(magic_version_2_0); |
53 | if (length > buf_size) { |
54 | length = buf_size; |
55 | } |
56 | if (!memcmp(magic_version_2_0, buf, length)) { |
57 | return 2; |
58 | } |
59 | return 0; |
60 | } |
61 | |
62 | static int cloop_open(BlockDriverState *bs, QDict *options, int flags, |
63 | Error **errp) |
64 | { |
65 | BDRVCloopState *s = bs->opaque; |
66 | uint32_t offsets_size, max_compressed_block_size = 1, i; |
67 | int ret; |
68 | |
69 | ret = bdrv_apply_auto_read_only(bs, NULL, errp); |
70 | if (ret < 0) { |
71 | return ret; |
72 | } |
73 | |
74 | bs->file = bdrv_open_child(NULL, options, "file" , bs, &child_file, |
75 | false, errp); |
76 | if (!bs->file) { |
77 | return -EINVAL; |
78 | } |
79 | |
80 | /* read header */ |
81 | ret = bdrv_pread(bs->file, 128, &s->block_size, 4); |
82 | if (ret < 0) { |
83 | return ret; |
84 | } |
85 | s->block_size = be32_to_cpu(s->block_size); |
86 | if (s->block_size % 512) { |
87 | error_setg(errp, "block_size %" PRIu32 " must be a multiple of 512" , |
88 | s->block_size); |
89 | return -EINVAL; |
90 | } |
91 | if (s->block_size == 0) { |
92 | error_setg(errp, "block_size cannot be zero" ); |
93 | return -EINVAL; |
94 | } |
95 | |
96 | /* cloop's create_compressed_fs.c warns about block sizes beyond 256 KB but |
97 | * we can accept more. Prevent ridiculous values like 4 GB - 1 since we |
98 | * need a buffer this big. |
99 | */ |
100 | if (s->block_size > MAX_BLOCK_SIZE) { |
101 | error_setg(errp, "block_size %" PRIu32 " must be %u MB or less" , |
102 | s->block_size, |
103 | MAX_BLOCK_SIZE / (1024 * 1024)); |
104 | return -EINVAL; |
105 | } |
106 | |
107 | ret = bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4); |
108 | if (ret < 0) { |
109 | return ret; |
110 | } |
111 | s->n_blocks = be32_to_cpu(s->n_blocks); |
112 | |
113 | /* read offsets */ |
114 | if (s->n_blocks > (UINT32_MAX - 1) / sizeof(uint64_t)) { |
115 | /* Prevent integer overflow */ |
116 | error_setg(errp, "n_blocks %" PRIu32 " must be %zu or less" , |
117 | s->n_blocks, |
118 | (UINT32_MAX - 1) / sizeof(uint64_t)); |
119 | return -EINVAL; |
120 | } |
121 | offsets_size = (s->n_blocks + 1) * sizeof(uint64_t); |
122 | if (offsets_size > 512 * 1024 * 1024) { |
123 | /* Prevent ridiculous offsets_size which causes memory allocation to |
124 | * fail or overflows bdrv_pread() size. In practice the 512 MB |
125 | * offsets[] limit supports 16 TB images at 256 KB block size. |
126 | */ |
127 | error_setg(errp, "image requires too many offsets, " |
128 | "try increasing block size" ); |
129 | return -EINVAL; |
130 | } |
131 | |
132 | s->offsets = g_try_malloc(offsets_size); |
133 | if (s->offsets == NULL) { |
134 | error_setg(errp, "Could not allocate offsets table" ); |
135 | return -ENOMEM; |
136 | } |
137 | |
138 | ret = bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size); |
139 | if (ret < 0) { |
140 | goto fail; |
141 | } |
142 | |
143 | for (i = 0; i < s->n_blocks + 1; i++) { |
144 | uint64_t size; |
145 | |
146 | s->offsets[i] = be64_to_cpu(s->offsets[i]); |
147 | if (i == 0) { |
148 | continue; |
149 | } |
150 | |
151 | if (s->offsets[i] < s->offsets[i - 1]) { |
152 | error_setg(errp, "offsets not monotonically increasing at " |
153 | "index %" PRIu32 ", image file is corrupt" , i); |
154 | ret = -EINVAL; |
155 | goto fail; |
156 | } |
157 | |
158 | size = s->offsets[i] - s->offsets[i - 1]; |
159 | |
160 | /* Compressed blocks should be smaller than the uncompressed block size |
161 | * but maybe compression performed poorly so the compressed block is |
162 | * actually bigger. Clamp down on unrealistic values to prevent |
163 | * ridiculous s->compressed_block allocation. |
164 | */ |
165 | if (size > 2 * MAX_BLOCK_SIZE) { |
166 | error_setg(errp, "invalid compressed block size at index %" PRIu32 |
167 | ", image file is corrupt" , i); |
168 | ret = -EINVAL; |
169 | goto fail; |
170 | } |
171 | |
172 | if (size > max_compressed_block_size) { |
173 | max_compressed_block_size = size; |
174 | } |
175 | } |
176 | |
177 | /* initialize zlib engine */ |
178 | s->compressed_block = g_try_malloc(max_compressed_block_size + 1); |
179 | if (s->compressed_block == NULL) { |
180 | error_setg(errp, "Could not allocate compressed_block" ); |
181 | ret = -ENOMEM; |
182 | goto fail; |
183 | } |
184 | |
185 | s->uncompressed_block = g_try_malloc(s->block_size); |
186 | if (s->uncompressed_block == NULL) { |
187 | error_setg(errp, "Could not allocate uncompressed_block" ); |
188 | ret = -ENOMEM; |
189 | goto fail; |
190 | } |
191 | |
192 | if (inflateInit(&s->zstream) != Z_OK) { |
193 | ret = -EINVAL; |
194 | goto fail; |
195 | } |
196 | s->current_block = s->n_blocks; |
197 | |
198 | s->sectors_per_block = s->block_size/512; |
199 | bs->total_sectors = s->n_blocks * s->sectors_per_block; |
200 | qemu_co_mutex_init(&s->lock); |
201 | return 0; |
202 | |
203 | fail: |
204 | g_free(s->offsets); |
205 | g_free(s->compressed_block); |
206 | g_free(s->uncompressed_block); |
207 | return ret; |
208 | } |
209 | |
210 | static void cloop_refresh_limits(BlockDriverState *bs, Error **errp) |
211 | { |
212 | bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */ |
213 | } |
214 | |
215 | static inline int cloop_read_block(BlockDriverState *bs, int block_num) |
216 | { |
217 | BDRVCloopState *s = bs->opaque; |
218 | |
219 | if (s->current_block != block_num) { |
220 | int ret; |
221 | uint32_t bytes = s->offsets[block_num + 1] - s->offsets[block_num]; |
222 | |
223 | ret = bdrv_pread(bs->file, s->offsets[block_num], |
224 | s->compressed_block, bytes); |
225 | if (ret != bytes) { |
226 | return -1; |
227 | } |
228 | |
229 | s->zstream.next_in = s->compressed_block; |
230 | s->zstream.avail_in = bytes; |
231 | s->zstream.next_out = s->uncompressed_block; |
232 | s->zstream.avail_out = s->block_size; |
233 | ret = inflateReset(&s->zstream); |
234 | if (ret != Z_OK) { |
235 | return -1; |
236 | } |
237 | ret = inflate(&s->zstream, Z_FINISH); |
238 | if (ret != Z_STREAM_END || s->zstream.total_out != s->block_size) { |
239 | return -1; |
240 | } |
241 | |
242 | s->current_block = block_num; |
243 | } |
244 | return 0; |
245 | } |
246 | |
247 | static int coroutine_fn |
248 | cloop_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, |
249 | QEMUIOVector *qiov, int flags) |
250 | { |
251 | BDRVCloopState *s = bs->opaque; |
252 | uint64_t sector_num = offset >> BDRV_SECTOR_BITS; |
253 | int nb_sectors = bytes >> BDRV_SECTOR_BITS; |
254 | int ret, i; |
255 | |
256 | assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); |
257 | assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); |
258 | |
259 | qemu_co_mutex_lock(&s->lock); |
260 | |
261 | for (i = 0; i < nb_sectors; i++) { |
262 | void *data; |
263 | uint32_t sector_offset_in_block = |
264 | ((sector_num + i) % s->sectors_per_block), |
265 | block_num = (sector_num + i) / s->sectors_per_block; |
266 | if (cloop_read_block(bs, block_num) != 0) { |
267 | ret = -EIO; |
268 | goto fail; |
269 | } |
270 | |
271 | data = s->uncompressed_block + sector_offset_in_block * 512; |
272 | qemu_iovec_from_buf(qiov, i * 512, data, 512); |
273 | } |
274 | |
275 | ret = 0; |
276 | fail: |
277 | qemu_co_mutex_unlock(&s->lock); |
278 | |
279 | return ret; |
280 | } |
281 | |
282 | static void cloop_close(BlockDriverState *bs) |
283 | { |
284 | BDRVCloopState *s = bs->opaque; |
285 | g_free(s->offsets); |
286 | g_free(s->compressed_block); |
287 | g_free(s->uncompressed_block); |
288 | inflateEnd(&s->zstream); |
289 | } |
290 | |
291 | static BlockDriver bdrv_cloop = { |
292 | .format_name = "cloop" , |
293 | .instance_size = sizeof(BDRVCloopState), |
294 | .bdrv_probe = cloop_probe, |
295 | .bdrv_open = cloop_open, |
296 | .bdrv_child_perm = bdrv_format_default_perms, |
297 | .bdrv_refresh_limits = cloop_refresh_limits, |
298 | .bdrv_co_preadv = cloop_co_preadv, |
299 | .bdrv_close = cloop_close, |
300 | }; |
301 | |
302 | static void bdrv_cloop_init(void) |
303 | { |
304 | bdrv_register(&bdrv_cloop); |
305 | } |
306 | |
307 | block_init(bdrv_cloop_init); |
308 | |