xref: /openbmc/qemu/block/dmg.c (revision 1f051dcb)
1 /*
2  * QEMU Block driver for DMG 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 "block/block-io.h"
27 #include "block/block_int.h"
28 #include "qemu/bswap.h"
29 #include "qemu/error-report.h"
30 #include "qemu/module.h"
31 #include "qemu/memalign.h"
32 #include "dmg.h"
33 
34 BdrvDmgUncompressFunc *dmg_uncompress_bz2;
35 BdrvDmgUncompressFunc *dmg_uncompress_lzfse;
36 
37 enum {
38     /* Limit chunk sizes to prevent unreasonable amounts of memory being used
39      * or truncating when converting to 32-bit types
40      */
41     DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */
42     DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512,
43 };
44 
45 enum {
46     /* DMG Block Type */
47     UDZE = 0, /* Zeroes */
48     UDRW,     /* RAW type */
49     UDIG,     /* Ignore */
50     UDCO = 0x80000004,
51     UDZO,
52     UDBZ,
53     ULFO,
54     UDCM = 0x7ffffffe, /* Comments */
55     UDLE = 0xffffffff  /* Last Entry */
56 };
57 
dmg_probe(const uint8_t * buf,int buf_size,const char * filename)58 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
59 {
60     int len;
61 
62     if (!filename) {
63         return 0;
64     }
65 
66     len = strlen(filename);
67     if (len > 4 && !strcmp(filename + len - 4, ".dmg")) {
68         return 2;
69     }
70     return 0;
71 }
72 
73 static int GRAPH_RDLOCK
read_uint64(BlockDriverState * bs,int64_t offset,uint64_t * result)74 read_uint64(BlockDriverState *bs, int64_t offset, uint64_t *result)
75 {
76     uint64_t buffer;
77     int ret;
78 
79     ret = bdrv_pread(bs->file, offset, 8, &buffer, 0);
80     if (ret < 0) {
81         return ret;
82     }
83 
84     *result = be64_to_cpu(buffer);
85     return 0;
86 }
87 
88 static int GRAPH_RDLOCK
read_uint32(BlockDriverState * bs,int64_t offset,uint32_t * result)89 read_uint32(BlockDriverState *bs, int64_t offset, uint32_t *result)
90 {
91     uint32_t buffer;
92     int ret;
93 
94     ret = bdrv_pread(bs->file, offset, 4, &buffer, 0);
95     if (ret < 0) {
96         return ret;
97     }
98 
99     *result = be32_to_cpu(buffer);
100     return 0;
101 }
102 
buff_read_uint64(const uint8_t * buffer,int64_t offset)103 static inline uint64_t buff_read_uint64(const uint8_t *buffer, int64_t offset)
104 {
105     return be64_to_cpu(*(uint64_t *)&buffer[offset]);
106 }
107 
buff_read_uint32(const uint8_t * buffer,int64_t offset)108 static inline uint32_t buff_read_uint32(const uint8_t *buffer, int64_t offset)
109 {
110     return be32_to_cpu(*(uint32_t *)&buffer[offset]);
111 }
112 
113 /* Increase max chunk sizes, if necessary.  This function is used to calculate
114  * the buffer sizes needed for compressed/uncompressed chunk I/O.
115  */
update_max_chunk_size(BDRVDMGState * s,uint32_t chunk,uint32_t * max_compressed_size,uint32_t * max_sectors_per_chunk)116 static void update_max_chunk_size(BDRVDMGState *s, uint32_t chunk,
117                                   uint32_t *max_compressed_size,
118                                   uint32_t *max_sectors_per_chunk)
119 {
120     uint32_t compressed_size = 0;
121     uint32_t uncompressed_sectors = 0;
122 
123     switch (s->types[chunk]) {
124     case UDZO: /* zlib compressed */
125     case UDBZ: /* bzip2 compressed */
126     case ULFO: /* lzfse compressed */
127         compressed_size = s->lengths[chunk];
128         uncompressed_sectors = s->sectorcounts[chunk];
129         break;
130     case UDRW: /* copy */
131         uncompressed_sectors = DIV_ROUND_UP(s->lengths[chunk], 512);
132         break;
133     case UDZE: /* zero */
134     case UDIG: /* ignore */
135         /* as the all-zeroes block may be large, it is treated specially: the
136          * sector is not copied from a large buffer, a simple memset is used
137          * instead. Therefore uncompressed_sectors does not need to be set. */
138         break;
139     }
140 
141     if (compressed_size > *max_compressed_size) {
142         *max_compressed_size = compressed_size;
143     }
144     if (uncompressed_sectors > *max_sectors_per_chunk) {
145         *max_sectors_per_chunk = uncompressed_sectors;
146     }
147 }
148 
dmg_find_koly_offset(BdrvChild * file,Error ** errp)149 static int64_t dmg_find_koly_offset(BdrvChild *file, Error **errp)
150 {
151     BlockDriverState *file_bs = file->bs;
152     int64_t length;
153     int64_t offset = 0;
154     uint8_t buffer[515];
155     int i, ret;
156 
157     /* bdrv_getlength returns a multiple of block size (512), rounded up. Since
158      * dmg images can have odd sizes, try to look for the "koly" magic which
159      * marks the begin of the UDIF trailer (512 bytes). This magic can be found
160      * in the last 511 bytes of the second-last sector or the first 4 bytes of
161      * the last sector (search space: 515 bytes) */
162     length = bdrv_getlength(file_bs);
163     if (length < 0) {
164         error_setg_errno(errp, -length,
165             "Failed to get file size while reading UDIF trailer");
166         return length;
167     } else if (length < 512) {
168         error_setg(errp, "dmg file must be at least 512 bytes long");
169         return -EINVAL;
170     }
171     if (length > 511 + 512) {
172         offset = length - 511 - 512;
173     }
174     length = length < 515 ? length : 515;
175     ret = bdrv_pread(file, offset, length, buffer, 0);
176     if (ret < 0) {
177         error_setg_errno(errp, -ret, "Failed while reading UDIF trailer");
178         return ret;
179     }
180     for (i = 0; i < length - 3; i++) {
181         if (buffer[i] == 'k' && buffer[i+1] == 'o' &&
182             buffer[i+2] == 'l' && buffer[i+3] == 'y') {
183             return offset + i;
184         }
185     }
186     error_setg(errp, "Could not locate UDIF trailer in dmg file");
187     return -EINVAL;
188 }
189 
190 /* used when building the sector table */
191 typedef struct DmgHeaderState {
192     /* used internally by dmg_read_mish_block to remember offsets of blocks
193      * across calls */
194     uint64_t data_fork_offset;
195     /* exported for dmg_open */
196     uint32_t max_compressed_size;
197     uint32_t max_sectors_per_chunk;
198 } DmgHeaderState;
199 
dmg_is_known_block_type(uint32_t entry_type)200 static bool dmg_is_known_block_type(uint32_t entry_type)
201 {
202     switch (entry_type) {
203     case UDZE:    /* zeros */
204     case UDRW:    /* uncompressed */
205     case UDIG:    /* ignore */
206     case UDZO:    /* zlib */
207         return true;
208     case UDBZ:    /* bzip2 */
209         return !!dmg_uncompress_bz2;
210     case ULFO:    /* lzfse */
211         return !!dmg_uncompress_lzfse;
212     default:
213         return false;
214     }
215 }
216 
dmg_read_mish_block(BDRVDMGState * s,DmgHeaderState * ds,uint8_t * buffer,uint32_t count)217 static int dmg_read_mish_block(BDRVDMGState *s, DmgHeaderState *ds,
218                                uint8_t *buffer, uint32_t count)
219 {
220     uint32_t type, i;
221     int ret;
222     size_t new_size;
223     uint32_t chunk_count;
224     int64_t offset = 0;
225     uint64_t data_offset;
226     uint64_t in_offset = ds->data_fork_offset;
227     uint64_t out_offset;
228 
229     type = buff_read_uint32(buffer, offset);
230     /* skip data that is not a valid MISH block (invalid magic or too small) */
231     if (type != 0x6d697368 || count < 244) {
232         /* assume success for now */
233         return 0;
234     }
235 
236     /* chunk offsets are relative to this sector number */
237     out_offset = buff_read_uint64(buffer, offset + 8);
238 
239     /* location in data fork for (compressed) blob (in bytes) */
240     data_offset = buff_read_uint64(buffer, offset + 0x18);
241     in_offset += data_offset;
242 
243     /* move to begin of chunk entries */
244     offset += 204;
245 
246     chunk_count = (count - 204) / 40;
247     new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
248     s->types = g_realloc(s->types, new_size / 2);
249     s->offsets = g_realloc(s->offsets, new_size);
250     s->lengths = g_realloc(s->lengths, new_size);
251     s->sectors = g_realloc(s->sectors, new_size);
252     s->sectorcounts = g_realloc(s->sectorcounts, new_size);
253 
254     for (i = s->n_chunks; i < s->n_chunks + chunk_count; i++) {
255         s->types[i] = buff_read_uint32(buffer, offset);
256         if (!dmg_is_known_block_type(s->types[i])) {
257             switch (s->types[i]) {
258             case UDBZ:
259                 warn_report_once("dmg-bzip2 module is missing, accessing bzip2 "
260                                  "compressed blocks will result in I/O errors");
261                 break;
262             case ULFO:
263                 warn_report_once("dmg-lzfse module is missing, accessing lzfse "
264                                  "compressed blocks will result in I/O errors");
265                 break;
266             case UDCM:
267             case UDLE:
268                 /* Comments and last entry can be ignored without problems */
269                 break;
270             default:
271                 warn_report_once("Image contains chunks of unknown type %x, "
272                                  "accessing them will result in I/O errors",
273                                  s->types[i]);
274                 break;
275             }
276             chunk_count--;
277             i--;
278             offset += 40;
279             continue;
280         }
281 
282         /* sector number */
283         s->sectors[i] = buff_read_uint64(buffer, offset + 8);
284         s->sectors[i] += out_offset;
285 
286         /* sector count */
287         s->sectorcounts[i] = buff_read_uint64(buffer, offset + 0x10);
288 
289         /* all-zeroes sector (type UDZE and UDIG) does not need to be
290          * "uncompressed" and can therefore be unbounded. */
291         if (s->types[i] != UDZE && s->types[i] != UDIG
292             && s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) {
293             error_report("sector count %" PRIu64 " for chunk %" PRIu32
294                          " is larger than max (%u)",
295                          s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX);
296             ret = -EINVAL;
297             goto fail;
298         }
299 
300         /* offset in (compressed) data fork */
301         s->offsets[i] = buff_read_uint64(buffer, offset + 0x18);
302         s->offsets[i] += in_offset;
303 
304         /* length in (compressed) data fork */
305         s->lengths[i] = buff_read_uint64(buffer, offset + 0x20);
306 
307         if (s->lengths[i] > DMG_LENGTHS_MAX) {
308             error_report("length %" PRIu64 " for chunk %" PRIu32
309                          " is larger than max (%u)",
310                          s->lengths[i], i, DMG_LENGTHS_MAX);
311             ret = -EINVAL;
312             goto fail;
313         }
314 
315         update_max_chunk_size(s, i, &ds->max_compressed_size,
316                               &ds->max_sectors_per_chunk);
317         offset += 40;
318     }
319     s->n_chunks += chunk_count;
320     return 0;
321 
322 fail:
323     return ret;
324 }
325 
326 static int GRAPH_RDLOCK
dmg_read_resource_fork(BlockDriverState * bs,DmgHeaderState * ds,uint64_t info_begin,uint64_t info_length)327 dmg_read_resource_fork(BlockDriverState *bs, DmgHeaderState *ds,
328                        uint64_t info_begin, uint64_t info_length)
329 {
330     BDRVDMGState *s = bs->opaque;
331     int ret;
332     uint32_t count, rsrc_data_offset;
333     uint8_t *buffer = NULL;
334     uint64_t info_end;
335     uint64_t offset;
336 
337     /* read offset from begin of resource fork (info_begin) to resource data */
338     ret = read_uint32(bs, info_begin, &rsrc_data_offset);
339     if (ret < 0) {
340         goto fail;
341     } else if (rsrc_data_offset > info_length) {
342         ret = -EINVAL;
343         goto fail;
344     }
345 
346     /* read length of resource data */
347     ret = read_uint32(bs, info_begin + 8, &count);
348     if (ret < 0) {
349         goto fail;
350     } else if (count == 0 || rsrc_data_offset + count > info_length) {
351         ret = -EINVAL;
352         goto fail;
353     }
354 
355     /* begin of resource data (consisting of one or more resources) */
356     offset = info_begin + rsrc_data_offset;
357 
358     /* end of resource data (there is possibly a following resource map
359      * which will be ignored). */
360     info_end = offset + count;
361 
362     /* read offsets (mish blocks) from one or more resources in resource data */
363     while (offset < info_end) {
364         /* size of following resource */
365         ret = read_uint32(bs, offset, &count);
366         if (ret < 0) {
367             goto fail;
368         } else if (count == 0 || count > info_end - offset) {
369             ret = -EINVAL;
370             goto fail;
371         }
372         offset += 4;
373 
374         buffer = g_realloc(buffer, count);
375         ret = bdrv_pread(bs->file, offset, count, buffer, 0);
376         if (ret < 0) {
377             goto fail;
378         }
379 
380         ret = dmg_read_mish_block(s, ds, buffer, count);
381         if (ret < 0) {
382             goto fail;
383         }
384         /* advance offset by size of resource */
385         offset += count;
386     }
387     ret = 0;
388 
389 fail:
390     g_free(buffer);
391     return ret;
392 }
393 
394 static int GRAPH_RDLOCK
dmg_read_plist_xml(BlockDriverState * bs,DmgHeaderState * ds,uint64_t info_begin,uint64_t info_length)395 dmg_read_plist_xml(BlockDriverState *bs, DmgHeaderState *ds,
396                    uint64_t info_begin, uint64_t info_length)
397 {
398     BDRVDMGState *s = bs->opaque;
399     int ret;
400     uint8_t *buffer = NULL;
401     char *data_begin, *data_end;
402 
403     /* Have at least some length to avoid NULL for g_malloc. Attempt to set a
404      * safe upper cap on the data length. A test sample had a XML length of
405      * about 1 MiB. */
406     if (info_length == 0 || info_length > 16 * 1024 * 1024) {
407         ret = -EINVAL;
408         goto fail;
409     }
410 
411     buffer = g_malloc(info_length + 1);
412     buffer[info_length] = '\0';
413     ret = bdrv_pread(bs->file, info_begin, info_length, buffer, 0);
414     if (ret < 0) {
415         ret = -EINVAL;
416         goto fail;
417     }
418 
419     /* look for <data>...</data>. The data is 284 (0x11c) bytes after base64
420      * decode. The actual data element has 431 (0x1af) bytes which includes tabs
421      * and line feeds. */
422     data_end = (char *)buffer;
423     while ((data_begin = strstr(data_end, "<data>")) != NULL) {
424         guchar *mish;
425         gsize out_len = 0;
426 
427         data_begin += 6;
428         data_end = strstr(data_begin, "</data>");
429         /* malformed XML? */
430         if (data_end == NULL) {
431             ret = -EINVAL;
432             goto fail;
433         }
434         *data_end++ = '\0';
435         mish = g_base64_decode(data_begin, &out_len);
436         ret = dmg_read_mish_block(s, ds, mish, (uint32_t)out_len);
437         g_free(mish);
438         if (ret < 0) {
439             goto fail;
440         }
441     }
442     ret = 0;
443 
444 fail:
445     g_free(buffer);
446     return ret;
447 }
448 
dmg_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)449 static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
450                     Error **errp)
451 {
452     BDRVDMGState *s = bs->opaque;
453     DmgHeaderState ds;
454     uint64_t rsrc_fork_offset, rsrc_fork_length;
455     uint64_t plist_xml_offset, plist_xml_length;
456     int64_t offset;
457     int ret;
458 
459     GLOBAL_STATE_CODE();
460 
461     bdrv_graph_rdlock_main_loop();
462     ret = bdrv_apply_auto_read_only(bs, NULL, errp);
463     bdrv_graph_rdunlock_main_loop();
464     if (ret < 0) {
465         return ret;
466     }
467 
468     ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
469     if (ret < 0) {
470         return ret;
471     }
472 
473     GRAPH_RDLOCK_GUARD_MAINLOOP();
474 
475     /*
476      * NB: if uncompress submodules are absent,
477      * ie block_module_load return value == 0, the function pointers
478      * dmg_uncompress_bz2 and dmg_uncompress_lzfse will be NULL.
479      */
480     if (block_module_load("dmg-bz2", errp) < 0) {
481         return -EINVAL;
482     }
483     if (block_module_load("dmg-lzfse", errp) < 0) {
484         return -EINVAL;
485     }
486 
487     s->n_chunks = 0;
488     s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
489     /* used by dmg_read_mish_block to keep track of the current I/O position */
490     ds.data_fork_offset = 0;
491     ds.max_compressed_size = 1;
492     ds.max_sectors_per_chunk = 1;
493 
494     /* locate the UDIF trailer */
495     offset = dmg_find_koly_offset(bs->file, errp);
496     if (offset < 0) {
497         ret = offset;
498         goto fail;
499     }
500 
501     /* offset of data fork (DataForkOffset) */
502     ret = read_uint64(bs, offset + 0x18, &ds.data_fork_offset);
503     if (ret < 0) {
504         goto fail;
505     } else if (ds.data_fork_offset > offset) {
506         ret = -EINVAL;
507         goto fail;
508     }
509 
510     /* offset of resource fork (RsrcForkOffset) */
511     ret = read_uint64(bs, offset + 0x28, &rsrc_fork_offset);
512     if (ret < 0) {
513         goto fail;
514     }
515     ret = read_uint64(bs, offset + 0x30, &rsrc_fork_length);
516     if (ret < 0) {
517         goto fail;
518     }
519     if (rsrc_fork_offset >= offset ||
520         rsrc_fork_length > offset - rsrc_fork_offset) {
521         ret = -EINVAL;
522         goto fail;
523     }
524     /* offset of property list (XMLOffset) */
525     ret = read_uint64(bs, offset + 0xd8, &plist_xml_offset);
526     if (ret < 0) {
527         goto fail;
528     }
529     ret = read_uint64(bs, offset + 0xe0, &plist_xml_length);
530     if (ret < 0) {
531         goto fail;
532     }
533     if (plist_xml_offset >= offset ||
534         plist_xml_length > offset - plist_xml_offset) {
535         ret = -EINVAL;
536         goto fail;
537     }
538     ret = read_uint64(bs, offset + 0x1ec, (uint64_t *)&bs->total_sectors);
539     if (ret < 0) {
540         goto fail;
541     }
542     if (bs->total_sectors < 0) {
543         ret = -EINVAL;
544         goto fail;
545     }
546     if (rsrc_fork_length != 0) {
547         ret = dmg_read_resource_fork(bs, &ds,
548                                      rsrc_fork_offset, rsrc_fork_length);
549         if (ret < 0) {
550             goto fail;
551         }
552     } else if (plist_xml_length != 0) {
553         ret = dmg_read_plist_xml(bs, &ds, plist_xml_offset, plist_xml_length);
554         if (ret < 0) {
555             goto fail;
556         }
557     } else {
558         ret = -EINVAL;
559         goto fail;
560     }
561 
562     /* initialize zlib engine */
563     s->compressed_chunk = qemu_try_blockalign(bs->file->bs,
564                                               ds.max_compressed_size + 1);
565     s->uncompressed_chunk = qemu_try_blockalign(bs->file->bs,
566                                                 512 * ds.max_sectors_per_chunk);
567     if (s->compressed_chunk == NULL || s->uncompressed_chunk == NULL) {
568         ret = -ENOMEM;
569         goto fail;
570     }
571 
572     if (inflateInit(&s->zstream) != Z_OK) {
573         ret = -EINVAL;
574         goto fail;
575     }
576 
577     s->current_chunk = s->n_chunks;
578 
579     qemu_co_mutex_init(&s->lock);
580     return 0;
581 
582 fail:
583     g_free(s->types);
584     g_free(s->offsets);
585     g_free(s->lengths);
586     g_free(s->sectors);
587     g_free(s->sectorcounts);
588     qemu_vfree(s->compressed_chunk);
589     qemu_vfree(s->uncompressed_chunk);
590     return ret;
591 }
592 
dmg_refresh_limits(BlockDriverState * bs,Error ** errp)593 static void dmg_refresh_limits(BlockDriverState *bs, Error **errp)
594 {
595     bs->bl.request_alignment = BDRV_SECTOR_SIZE; /* No sub-sector I/O */
596 }
597 
is_sector_in_chunk(BDRVDMGState * s,uint32_t chunk_num,uint64_t sector_num)598 static inline int is_sector_in_chunk(BDRVDMGState *s,
599                 uint32_t chunk_num, uint64_t sector_num)
600 {
601     if (chunk_num >= s->n_chunks || s->sectors[chunk_num] > sector_num ||
602             s->sectors[chunk_num] + s->sectorcounts[chunk_num] <= sector_num) {
603         return 0;
604     } else {
605         return -1;
606     }
607 }
608 
search_chunk(BDRVDMGState * s,uint64_t sector_num)609 static inline uint32_t search_chunk(BDRVDMGState *s, uint64_t sector_num)
610 {
611     /* binary search */
612     uint32_t chunk1 = 0, chunk2 = s->n_chunks, chunk3;
613     while (chunk1 <= chunk2) {
614         chunk3 = (chunk1 + chunk2) / 2;
615         if (s->sectors[chunk3] > sector_num) {
616             if (chunk3 == 0) {
617                 goto err;
618             }
619             chunk2 = chunk3 - 1;
620         } else if (s->sectors[chunk3] + s->sectorcounts[chunk3] > sector_num) {
621             return chunk3;
622         } else {
623             chunk1 = chunk3 + 1;
624         }
625     }
626 err:
627     return s->n_chunks; /* error */
628 }
629 
630 static int coroutine_fn GRAPH_RDLOCK
dmg_read_chunk(BlockDriverState * bs,uint64_t sector_num)631 dmg_read_chunk(BlockDriverState *bs, uint64_t sector_num)
632 {
633     BDRVDMGState *s = bs->opaque;
634 
635     if (!is_sector_in_chunk(s, s->current_chunk, sector_num)) {
636         int ret;
637         uint32_t chunk = search_chunk(s, sector_num);
638 
639         if (chunk >= s->n_chunks) {
640             return -1;
641         }
642 
643         s->current_chunk = s->n_chunks;
644         switch (s->types[chunk]) { /* block entry type */
645         case UDZO: { /* zlib compressed */
646             /* we need to buffer, because only the chunk as whole can be
647              * inflated. */
648             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
649                                 s->compressed_chunk, 0);
650             if (ret < 0) {
651                 return -1;
652             }
653 
654             s->zstream.next_in = s->compressed_chunk;
655             s->zstream.avail_in = s->lengths[chunk];
656             s->zstream.next_out = s->uncompressed_chunk;
657             s->zstream.avail_out = 512 * s->sectorcounts[chunk];
658             ret = inflateReset(&s->zstream);
659             if (ret != Z_OK) {
660                 return -1;
661             }
662             ret = inflate(&s->zstream, Z_FINISH);
663             if (ret != Z_STREAM_END ||
664                 s->zstream.total_out != 512 * s->sectorcounts[chunk]) {
665                 return -1;
666             }
667             break; }
668         case UDBZ: /* bzip2 compressed */
669             if (!dmg_uncompress_bz2) {
670                 break;
671             }
672             /* we need to buffer, because only the chunk as whole can be
673              * inflated. */
674             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
675                                 s->compressed_chunk, 0);
676             if (ret < 0) {
677                 return -1;
678             }
679 
680             ret = dmg_uncompress_bz2((char *)s->compressed_chunk,
681                                      (unsigned int) s->lengths[chunk],
682                                      (char *)s->uncompressed_chunk,
683                                      (unsigned int)
684                                          (512 * s->sectorcounts[chunk]));
685             if (ret < 0) {
686                 return ret;
687             }
688             break;
689         case ULFO:
690             if (!dmg_uncompress_lzfse) {
691                 break;
692             }
693             /* we need to buffer, because only the chunk as whole can be
694              * inflated. */
695             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
696                                 s->compressed_chunk, 0);
697             if (ret < 0) {
698                 return -1;
699             }
700 
701             ret = dmg_uncompress_lzfse((char *)s->compressed_chunk,
702                                        (unsigned int) s->lengths[chunk],
703                                        (char *)s->uncompressed_chunk,
704                                        (unsigned int)
705                                            (512 * s->sectorcounts[chunk]));
706             if (ret < 0) {
707                 return ret;
708             }
709             break;
710         case UDRW: /* copy */
711             ret = bdrv_co_pread(bs->file, s->offsets[chunk], s->lengths[chunk],
712                                 s->uncompressed_chunk, 0);
713             if (ret < 0) {
714                 return -1;
715             }
716             break;
717         case UDZE: /* zeros */
718         case UDIG: /* ignore */
719             /* see dmg_read, it is treated specially. No buffer needs to be
720              * pre-filled, the zeroes can be set directly. */
721             break;
722         }
723         s->current_chunk = chunk;
724     }
725     return 0;
726 }
727 
728 static int coroutine_fn GRAPH_RDLOCK
dmg_co_preadv(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)729 dmg_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
730               QEMUIOVector *qiov, BdrvRequestFlags flags)
731 {
732     BDRVDMGState *s = bs->opaque;
733     uint64_t sector_num = offset >> BDRV_SECTOR_BITS;
734     int nb_sectors = bytes >> BDRV_SECTOR_BITS;
735     int ret, i;
736 
737     assert(QEMU_IS_ALIGNED(offset, BDRV_SECTOR_SIZE));
738     assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));
739 
740     qemu_co_mutex_lock(&s->lock);
741 
742     for (i = 0; i < nb_sectors; i++) {
743         uint32_t sector_offset_in_chunk;
744         void *data;
745 
746         if (dmg_read_chunk(bs, sector_num + i) != 0) {
747             ret = -EIO;
748             goto fail;
749         }
750         /* Special case: current chunk is all zeroes. Do not perform a memcpy as
751          * s->uncompressed_chunk may be too small to cover the large all-zeroes
752          * section. dmg_read_chunk is called to find s->current_chunk */
753         if (s->types[s->current_chunk] == UDZE
754             || s->types[s->current_chunk] == UDIG) { /* all zeroes block entry */
755             qemu_iovec_memset(qiov, i * 512, 0, 512);
756             continue;
757         }
758         sector_offset_in_chunk = sector_num + i - s->sectors[s->current_chunk];
759         data = s->uncompressed_chunk + sector_offset_in_chunk * 512;
760         qemu_iovec_from_buf(qiov, i * 512, data, 512);
761     }
762 
763     ret = 0;
764 fail:
765     qemu_co_mutex_unlock(&s->lock);
766     return ret;
767 }
768 
dmg_close(BlockDriverState * bs)769 static void dmg_close(BlockDriverState *bs)
770 {
771     BDRVDMGState *s = bs->opaque;
772 
773     g_free(s->types);
774     g_free(s->offsets);
775     g_free(s->lengths);
776     g_free(s->sectors);
777     g_free(s->sectorcounts);
778     qemu_vfree(s->compressed_chunk);
779     qemu_vfree(s->uncompressed_chunk);
780 
781     inflateEnd(&s->zstream);
782 }
783 
784 static BlockDriver bdrv_dmg = {
785     .format_name    = "dmg",
786     .instance_size  = sizeof(BDRVDMGState),
787     .bdrv_probe     = dmg_probe,
788     .bdrv_open      = dmg_open,
789     .bdrv_refresh_limits = dmg_refresh_limits,
790     .bdrv_child_perm     = bdrv_default_perms,
791     .bdrv_co_preadv = dmg_co_preadv,
792     .bdrv_close     = dmg_close,
793     .is_format      = true,
794 };
795 
bdrv_dmg_init(void)796 static void bdrv_dmg_init(void)
797 {
798     bdrv_register(&bdrv_dmg);
799 }
800 
801 block_init(bdrv_dmg_init);
802