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1.1 root 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-common.h"
25: #include "block_int.h"
26: #include "bswap.h"
27: #include "module.h"
28: #include <zlib.h>
29:
30: typedef struct BDRVDMGState {
31: int fd;
32:
33: /* each chunk contains a certain number of sectors,
34: * offsets[i] is the offset in the .dmg file,
35: * lengths[i] is the length of the compressed chunk,
36: * sectors[i] is the sector beginning at offsets[i],
37: * sectorcounts[i] is the number of sectors in that chunk,
38: * the sectors array is ordered
39: * 0<=i<n_chunks */
40:
41: uint32_t n_chunks;
42: uint32_t* types;
43: uint64_t* offsets;
44: uint64_t* lengths;
45: uint64_t* sectors;
46: uint64_t* sectorcounts;
47: uint32_t current_chunk;
48: uint8_t *compressed_chunk;
49: uint8_t *uncompressed_chunk;
50: z_stream zstream;
51: } BDRVDMGState;
52:
53: static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename)
54: {
55: int len=strlen(filename);
56: if(len>4 && !strcmp(filename+len-4,".dmg"))
57: return 2;
58: return 0;
59: }
60:
61: static off_t read_off(int fd)
62: {
63: uint64_t buffer;
64: if(read(fd,&buffer,8)<8)
65: return 0;
66: return be64_to_cpu(buffer);
67: }
68:
69: static off_t read_uint32(int fd)
70: {
71: uint32_t buffer;
72: if(read(fd,&buffer,4)<4)
73: return 0;
74: return be32_to_cpu(buffer);
75: }
76:
77: static int dmg_open(BlockDriverState *bs, const char *filename, int flags)
78: {
79: BDRVDMGState *s = bs->opaque;
80: off_t info_begin,info_end,last_in_offset,last_out_offset;
81: uint32_t count;
82: uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i;
83:
84: s->fd = open(filename, O_RDONLY | O_BINARY);
85: if (s->fd < 0)
86: return -errno;
87: bs->read_only = 1;
88: s->n_chunks = 0;
89: s->offsets = s->lengths = s->sectors = s->sectorcounts = NULL;
90:
91: /* read offset of info blocks */
92: if(lseek(s->fd,-0x1d8,SEEK_END)<0) {
1.1.1.2 ! root 93: goto fail;
1.1 root 94: }
1.1.1.2 ! root 95:
1.1 root 96: info_begin=read_off(s->fd);
97: if(info_begin==0)
1.1.1.2 ! root 98: goto fail;
1.1 root 99: if(lseek(s->fd,info_begin,SEEK_SET)<0)
1.1.1.2 ! root 100: goto fail;
1.1 root 101: if(read_uint32(s->fd)!=0x100)
1.1.1.2 ! root 102: goto fail;
1.1 root 103: if((count = read_uint32(s->fd))==0)
1.1.1.2 ! root 104: goto fail;
1.1 root 105: info_end = info_begin+count;
106: if(lseek(s->fd,0xf8,SEEK_CUR)<0)
1.1.1.2 ! root 107: goto fail;
1.1 root 108:
109: /* read offsets */
110: last_in_offset = last_out_offset = 0;
111: while(lseek(s->fd,0,SEEK_CUR)<info_end) {
112: uint32_t type;
113:
114: count = read_uint32(s->fd);
115: if(count==0)
1.1.1.2 ! root 116: goto fail;
1.1 root 117: type = read_uint32(s->fd);
118: if(type!=0x6d697368 || count<244)
119: lseek(s->fd,count-4,SEEK_CUR);
120: else {
121: int new_size, chunk_count;
122: if(lseek(s->fd,200,SEEK_CUR)<0)
1.1.1.2 ! root 123: goto fail;
1.1 root 124: chunk_count = (count-204)/40;
125: new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count);
126: s->types = qemu_realloc(s->types, new_size/2);
127: s->offsets = qemu_realloc(s->offsets, new_size);
128: s->lengths = qemu_realloc(s->lengths, new_size);
129: s->sectors = qemu_realloc(s->sectors, new_size);
130: s->sectorcounts = qemu_realloc(s->sectorcounts, new_size);
131:
132: for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) {
133: s->types[i] = read_uint32(s->fd);
134: if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) {
135: if(s->types[i]==0xffffffff) {
136: last_in_offset = s->offsets[i-1]+s->lengths[i-1];
137: last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1];
138: }
139: chunk_count--;
140: i--;
141: if(lseek(s->fd,36,SEEK_CUR)<0)
1.1.1.2 ! root 142: goto fail;
1.1 root 143: continue;
144: }
145: read_uint32(s->fd);
146: s->sectors[i] = last_out_offset+read_off(s->fd);
147: s->sectorcounts[i] = read_off(s->fd);
148: s->offsets[i] = last_in_offset+read_off(s->fd);
149: s->lengths[i] = read_off(s->fd);
150: if(s->lengths[i]>max_compressed_size)
151: max_compressed_size = s->lengths[i];
152: if(s->sectorcounts[i]>max_sectors_per_chunk)
153: max_sectors_per_chunk = s->sectorcounts[i];
154: }
155: s->n_chunks+=chunk_count;
156: }
157: }
158:
159: /* initialize zlib engine */
160: s->compressed_chunk = qemu_malloc(max_compressed_size+1);
161: s->uncompressed_chunk = qemu_malloc(512*max_sectors_per_chunk);
162: if(inflateInit(&s->zstream) != Z_OK)
1.1.1.2 ! root 163: goto fail;
1.1 root 164:
165: s->current_chunk = s->n_chunks;
166:
167: return 0;
1.1.1.2 ! root 168: fail:
! 169: close(s->fd);
! 170: return -1;
1.1 root 171: }
172:
173: static inline int is_sector_in_chunk(BDRVDMGState* s,
174: uint32_t chunk_num,int sector_num)
175: {
176: if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num ||
177: s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num)
178: return 0;
179: else
180: return -1;
181: }
182:
183: static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num)
184: {
185: /* binary search */
186: uint32_t chunk1=0,chunk2=s->n_chunks,chunk3;
187: while(chunk1!=chunk2) {
188: chunk3 = (chunk1+chunk2)/2;
189: if(s->sectors[chunk3]>sector_num)
190: chunk2 = chunk3;
191: else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num)
192: return chunk3;
193: else
194: chunk1 = chunk3;
195: }
196: return s->n_chunks; /* error */
197: }
198:
199: static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num)
200: {
201: if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) {
202: int ret;
203: uint32_t chunk = search_chunk(s,sector_num);
204:
205: if(chunk>=s->n_chunks)
206: return -1;
207:
208: s->current_chunk = s->n_chunks;
209: switch(s->types[chunk]) {
210: case 0x80000005: { /* zlib compressed */
211: int i;
212:
213: ret = lseek(s->fd, s->offsets[chunk], SEEK_SET);
214: if(ret<0)
215: return -1;
216:
217: /* we need to buffer, because only the chunk as whole can be
218: * inflated. */
219: i=0;
220: do {
221: ret = read(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i);
222: if(ret<0 && errno==EINTR)
223: ret=0;
224: i+=ret;
225: } while(ret>=0 && ret+i<s->lengths[chunk]);
226:
227: if (ret != s->lengths[chunk])
228: return -1;
229:
230: s->zstream.next_in = s->compressed_chunk;
231: s->zstream.avail_in = s->lengths[chunk];
232: s->zstream.next_out = s->uncompressed_chunk;
233: s->zstream.avail_out = 512*s->sectorcounts[chunk];
234: ret = inflateReset(&s->zstream);
235: if(ret != Z_OK)
236: return -1;
237: ret = inflate(&s->zstream, Z_FINISH);
238: if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk])
239: return -1;
240: break; }
241: case 1: /* copy */
242: ret = read(s->fd, s->uncompressed_chunk, s->lengths[chunk]);
243: if (ret != s->lengths[chunk])
244: return -1;
245: break;
246: case 2: /* zero */
247: memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]);
248: break;
249: }
250: s->current_chunk = chunk;
251: }
252: return 0;
253: }
254:
255: static int dmg_read(BlockDriverState *bs, int64_t sector_num,
256: uint8_t *buf, int nb_sectors)
257: {
258: BDRVDMGState *s = bs->opaque;
259: int i;
260:
261: for(i=0;i<nb_sectors;i++) {
262: uint32_t sector_offset_in_chunk;
263: if(dmg_read_chunk(s, sector_num+i) != 0)
264: return -1;
265: sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk];
266: memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512);
267: }
268: return 0;
269: }
270:
271: static void dmg_close(BlockDriverState *bs)
272: {
273: BDRVDMGState *s = bs->opaque;
274: close(s->fd);
275: if(s->n_chunks>0) {
276: free(s->types);
277: free(s->offsets);
278: free(s->lengths);
279: free(s->sectors);
280: free(s->sectorcounts);
281: }
282: free(s->compressed_chunk);
283: free(s->uncompressed_chunk);
284: inflateEnd(&s->zstream);
285: }
286:
287: static BlockDriver bdrv_dmg = {
288: .format_name = "dmg",
289: .instance_size = sizeof(BDRVDMGState),
290: .bdrv_probe = dmg_probe,
291: .bdrv_open = dmg_open,
292: .bdrv_read = dmg_read,
293: .bdrv_close = dmg_close,
294: };
295:
296: static void bdrv_dmg_init(void)
297: {
298: bdrv_register(&bdrv_dmg);
299: }
300:
301: block_init(bdrv_dmg_init);
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