1 | /*␊ |
2 | * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.␊ |
3 | *␊ |
4 | * @APPLE_LICENSE_HEADER_START@␊ |
5 | * ␊ |
6 | * The contents of this file constitute Original Code as defined in and␊ |
7 | * are subject to the Apple Public Source License Version 2.0 (the␊ |
8 | * "License"). You may not use this file except in compliance with the␊ |
9 | * License. Please obtain a copy of the License at␊ |
10 | * http://www.apple.com/publicsource and read it before using this file.␊ |
11 | * ␊ |
12 | * This Original Code and all software distributed under the License are␊ |
13 | * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER␊ |
14 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,␊ |
15 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,␊ |
16 | * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the␊ |
17 | * License for the specific language governing rights and limitations␊ |
18 | * under the License.␊ |
19 | * ␊ |
20 | * @APPLE_LICENSE_HEADER_END@␊ |
21 | */␊ |
22 | /*␊ |
23 | * ufs.c - File System Module for UFS.␊ |
24 | *␊ |
25 | * Copyright (c) 1998-2002 Apple Computer, Inc.␊ |
26 | *␊ |
27 | * DRI: Josh de Cesare␊ |
28 | */␊ |
29 | ␊ |
30 | #include <sl.h>␊ |
31 | ␊ |
32 | #include "ufs.h"␊ |
33 | #include "ufs_byteorder.h"␊ |
34 | ␊ |
35 | #if !defined(MAXNAMLEN) && defined(UFSMAXNAMLEN)␊ |
36 | #define MAXNAMLEN UFSMAXNAMLEN␊ |
37 | #endif␊ |
38 | ␊ |
39 | typedef struct dinode Inode, *InodePtr;␊ |
40 | ␊ |
41 | // Private function prototypes␊ |
42 | ␊ |
43 | static char *ReadBlock(long fragNum, long fragOffset, long length,␊ |
44 | char *buffer, long cache);␊ |
45 | static long ReadInode(long inodeNum, InodePtr inode, long *flags, long *time);␊ |
46 | static long ResolvePathToInode(char *filePath, long *flags,␊ |
47 | InodePtr fileInode, InodePtr dirInode);␊ |
48 | static long ReadDirEntry(InodePtr dirInode, long *fileInodeNum,␊ |
49 | long long *dirIndex, char **name);␊ |
50 | static long FindFileInDir(char *fileName, long *flags,␊ |
51 | InodePtr fileInode, InodePtr dirInode);␊ |
52 | static char *ReadFileBlock(InodePtr fileInode, long fragNum, long blockOffset,␊ |
53 | long length, char *buffer, long cache);␊ |
54 | static long ReadFile(InodePtr fileInode, uint64_t *length, void *base, uint64_t offset);␊ |
55 | ␊ |
56 | #define kDevBlockSize (0x200) // Size of each disk block.␊ |
57 | #define kDiskLabelBlock (15) // Block the DL is in.␊ |
58 | ␊ |
59 | #ifdef __i386__␊ |
60 | ␊ |
61 | static CICell gCurrentIH;␊ |
62 | static long long gPartitionBase;␊ |
63 | static char *gULBuf;␊ |
64 | static char *gFSBuf;␊ |
65 | static struct fs *gFS;␊ |
66 | #if !BOOT1␊ |
67 | static struct ufslabel gUFSLabel; // for UUID␊ |
68 | #endif␊ |
69 | static long gBlockSize;␊ |
70 | static long gFragSize;␊ |
71 | static long gFragsPerBlock;␊ |
72 | static char *gTempBlock;␊ |
73 | static char *gTempName;␊ |
74 | static char *gTempName2;␊ |
75 | static InodePtr gRootInodePtr;␊ |
76 | static InodePtr gFileInodePtr;␊ |
77 | ␊ |
78 | #else /* !__i386__ */␊ |
79 | ␊ |
80 | static CICell gCurrentIH;␊ |
81 | static long long gPartitionBase;␊ |
82 | static char gDLBuf[8192];␊ |
83 | static char gFSBuf[SBSIZE];␊ |
84 | static struct fs *gFS;␊ |
85 | #if !BOOT1␊ |
86 | static struct ufslabel gUFSLabel; // for UUID␊ |
87 | #endif␊ |
88 | static long gBlockSize;␊ |
89 | static long gFragSize;␊ |
90 | static long gFragsPerBlock;␊ |
91 | static char *gTempBlock;␊ |
92 | static char gTempName[MAXNAMLEN + 1];␊ |
93 | static char gTempName2[MAXNAMLEN + 1];␊ |
94 | static Inode _gRootInode;␊ |
95 | static Inode _gFileInode;␊ |
96 | static InodePtr gRootInodePtr = &_gRootInode;␊ |
97 | static InodePtr gFileInodePtr = &_gFileInode;␊ |
98 | ␊ |
99 | #endif /* !__i386__ */␊ |
100 | ␊ |
101 | // Public functions␊ |
102 | ␊ |
103 | void UFSFree(CICell ih)␊ |
104 | {␊ |
105 | if(gCurrentIH == ih)␊ |
106 | gCurrentIH = 0;␊ |
107 | free(ih);␊ |
108 | }␊ |
109 | ␊ |
110 | long UFSInitPartition( CICell ih )␊ |
111 | {␊ |
112 | #if !BOOT1␊ |
113 | long ret;␊ |
114 | #endif␊ |
115 | ␊ |
116 | if (ih == gCurrentIH) {␊ |
117 | #ifdef __i386__␊ |
118 | CacheInit(ih, gBlockSize);␊ |
119 | #endif␊ |
120 | return 0;␊ |
121 | }␊ |
122 | ␊ |
123 | #if !BOOT1␊ |
124 | verbose("UFSInitPartition: %x\n", ih);␊ |
125 | #endif␊ |
126 | ␊ |
127 | gCurrentIH = 0;␊ |
128 | ␊ |
129 | #ifdef __i386__␊ |
130 | if (!gULBuf) gULBuf = (char *) malloc(UFS_LABEL_SIZE);␊ |
131 | if (!gFSBuf) gFSBuf = (char *) malloc(SBSIZE);␊ |
132 | if (!gTempName) gTempName = (char *) malloc(MAXNAMLEN + 1);␊ |
133 | if (!gTempName2) gTempName2 = (char *) malloc(MAXNAMLEN + 1);␊ |
134 | if (!gRootInodePtr) gRootInodePtr = (InodePtr) malloc(sizeof(Inode));␊ |
135 | if (!gFileInodePtr) gFileInodePtr = (InodePtr) malloc(sizeof(Inode));␊ |
136 | if (!gULBuf || !gFSBuf || !gTempName || !gTempName2 ||␊ |
137 | !gRootInodePtr || !gFileInodePtr) return -1;␊ |
138 | #endif␊ |
139 | ␊ |
140 | // Assume there is no Disk Label␊ |
141 | gPartitionBase = 0;␊ |
142 | ␊ |
143 | #if !BOOT1␊ |
144 | // read the disk label to get the UUID␊ |
145 | // (rumor has it that UFS headers can be either-endian on disk; hopefully␊ |
146 | // that isn't true for this UUID field).␊ |
147 | Seek(ih, gPartitionBase + UFS_LABEL_OFFSET);␊ |
148 | ret = Read(ih, (long)&gUFSLabel, UFS_LABEL_SIZE);␊ |
149 | if(ret != 0)␊ |
150 | bzero(&gUFSLabel, UFS_LABEL_SIZE);␊ |
151 | #endif /* !BOOT1 */␊ |
152 | ␊ |
153 | // Look for the Super Block␊ |
154 | Seek(ih, gPartitionBase + SBOFF);␊ |
155 | Read(ih, (long)gFSBuf, SBSIZE);␊ |
156 | ␊ |
157 | gFS = (struct fs *)gFSBuf;␊ |
158 | byte_swap_superblock(gFS);␊ |
159 | ␊ |
160 | if (gFS->fs_magic != FS_MAGIC) {␊ |
161 | return -1;␊ |
162 | }␊ |
163 | ␊ |
164 | ␉ih->modTime = gFS->fs_time;␊ |
165 | ␉␊ |
166 | // Calculate the block size and set up the block cache.␊ |
167 | gBlockSize = gFS->fs_bsize;␊ |
168 | gFragSize = gFS->fs_fsize;␊ |
169 | gFragsPerBlock = gBlockSize / gFragSize;␊ |
170 | if (gTempBlock != 0) free(gTempBlock);␊ |
171 | gTempBlock = malloc(gBlockSize);␊ |
172 | CacheInit(ih, gBlockSize);␊ |
173 | ␊ |
174 | gCurrentIH = ih;␊ |
175 | ␊ |
176 | // Read the Root Inode␊ |
177 | ReadInode(ROOTINO, gRootInodePtr, 0, 0);␊ |
178 | ␊ |
179 | return 0;␊ |
180 | }␊ |
181 | ␊ |
182 | #if !BOOT1␊ |
183 | ␊ |
184 | long UFSGetUUID(CICell ih, char *uuidStr)␊ |
185 | {␊ |
186 | long long uuid = gUFSLabel.ul_uuid;␊ |
187 | ␊ |
188 | if (UFSInitPartition(ih) == -1) return -1;␊ |
189 | if (uuid == 0LL) return -1;␊ |
190 | ␊ |
191 | return CreateUUIDString((uint8_t*)(&uuid), sizeof(uuid), uuidStr);␊ |
192 | }␊ |
193 | ␊ |
194 | #endif /* !BOOT1 */␊ |
195 | ␊ |
196 | long UFSLoadFile( CICell ih, char * filePath )␊ |
197 | {␊ |
198 | return UFSReadFile(ih, filePath, (void *)gFSLoadAddress, 0, 0);␊ |
199 | }␊ |
200 | ␊ |
201 | long UFSReadFile( CICell ih, char * filePath, void * base, uint64_t offset, uint64_t length )␊ |
202 | {␊ |
203 | long ret, flags;␊ |
204 | ␊ |
205 | #if !BOOT1␊ |
206 | verbose("Loading UFS file: [%s] from %x.\n", filePath, (unsigned)ih);␊ |
207 | #endif␊ |
208 | ␊ |
209 | if (UFSInitPartition(ih) == -1) return -1;␊ |
210 | ␊ |
211 | // Skip one or two leading '/'.␊ |
212 | if (*filePath == '/') filePath++;␊ |
213 | if (*filePath == '/') filePath++;␊ |
214 | ␊ |
215 | ret = ResolvePathToInode(filePath, &flags, gFileInodePtr, gRootInodePtr);␊ |
216 | if ((ret == -1) || ((flags & kFileTypeMask) != kFileTypeFlat)) return -1;␊ |
217 | ␊ |
218 | ret = ReadFile(gFileInodePtr, &length, base, offset);␊ |
219 | if (ret == -1) return -1;␊ |
220 | ␊ |
221 | return length;␊ |
222 | }␊ |
223 | ␊ |
224 | #ifndef BOOT1␊ |
225 | ␊ |
226 | long UFSGetDirEntry( CICell ih, char * dirPath, long long * dirIndex,␊ |
227 | char ** name, long * flags, long * time,␊ |
228 | FinderInfo * finderInfo, long * infoValid)␊ |
229 | {␊ |
230 | long ret, fileInodeNum, dirFlags;␊ |
231 | Inode tmpInode;␊ |
232 | ␊ |
233 | if (UFSInitPartition(ih) == -1) return -1;␊ |
234 | ␊ |
235 | if (infoValid) *infoValid = 0;␊ |
236 | ␊ |
237 | // Skip a leading '/' if present␊ |
238 | if (*dirPath == '/') dirPath++;␊ |
239 | if (*dirPath == '/') dirPath++;␊ |
240 | ␊ |
241 | ret = ResolvePathToInode(dirPath, &dirFlags, gFileInodePtr, gRootInodePtr);␊ |
242 | if ((ret == -1) || ((dirFlags & kFileTypeMask) != kFileTypeDirectory))␊ |
243 | return -1;␊ |
244 | ␊ |
245 | ret = ReadDirEntry(gFileInodePtr, &fileInodeNum, dirIndex, name);␊ |
246 | if (ret != 0) return ret;␊ |
247 | ␊ |
248 | ReadInode(fileInodeNum, &tmpInode, flags, time);␊ |
249 | ␊ |
250 | return 0;␊ |
251 | }␊ |
252 | ␊ |
253 | void␊ |
254 | UFSGetDescription(CICell ih, char *str, long strMaxLen)␊ |
255 | {␊ |
256 | if (UFSInitPartition(ih) == -1) { return; }␊ |
257 | ␊ |
258 | struct ufslabel *ul;␊ |
259 | ␊ |
260 | // Look for the Disk Label␊ |
261 | Seek(ih, 1ULL * UFS_LABEL_OFFSET);␊ |
262 | Read(ih, (long)gULBuf, UFS_LABEL_SIZE);␊ |
263 | ␊ |
264 | ul = (struct ufslabel *)gULBuf;␊ |
265 | ␊ |
266 | unsigned char magic_bytes[] = UFS_LABEL_MAGIC;␊ |
267 | int i;␊ |
268 | unsigned char *p = (unsigned char *)&ul->ul_magic;␊ |
269 | ␊ |
270 | for (i=0; i<sizeof(magic_bytes); i++, p++) {␊ |
271 | if (*p != magic_bytes[i])␊ |
272 | return;␊ |
273 | }␊ |
274 | strncpy(str, (const char *)ul->ul_name, strMaxLen);␊ |
275 | }␊ |
276 | ␊ |
277 | long␊ |
278 | UFSGetFileBlock(CICell ih, char *filePath, unsigned long long *firstBlock)␊ |
279 | {␊ |
280 | long ret, flags;␊ |
281 | ␊ |
282 | if (UFSInitPartition(ih) == -1) return -1;␊ |
283 | ␊ |
284 | // Skip one or two leading '/'.␊ |
285 | if (*filePath == '/') filePath++;␊ |
286 | if (*filePath == '/') filePath++;␊ |
287 | ␊ |
288 | ret = ResolvePathToInode(filePath, &flags, gFileInodePtr, gRootInodePtr);␊ |
289 | if ((ret == -1) || ((flags & kFileTypeMask) != kFileTypeFlat)) return -1;␊ |
290 | ␊ |
291 | *firstBlock = (gPartitionBase + 1ULL * gFileInodePtr->di_db[0] * gBlockSize) / 512ULL;␊ |
292 | ␊ |
293 | return 0;␊ |
294 | }␊ |
295 | ␊ |
296 | ␊ |
297 | #endif /* !BOOT1 */␊ |
298 | ␊ |
299 | // Private functions␊ |
300 | ␊ |
301 | static char * ReadBlock( long fragNum, long blockOffset, long length,␊ |
302 | char * buffer, long cache )␊ |
303 | {␊ |
304 | long long offset;␊ |
305 | long blockNum;␊ |
306 | ␊ |
307 | blockNum = fragNum / gFragsPerBlock;␊ |
308 | fragNum -= blockNum * gFragsPerBlock;␊ |
309 | ␊ |
310 | blockOffset += fragNum * gFragSize;␊ |
311 | ␊ |
312 | offset = gPartitionBase + 1ULL * blockNum * gBlockSize;␊ |
313 | ␊ |
314 | if (cache && ((blockOffset + length) <= gBlockSize)) {␊ |
315 | CacheRead(gCurrentIH, gTempBlock, offset, gBlockSize, 1);␊ |
316 | if (buffer != 0) bcopy(gTempBlock + blockOffset, buffer, length);␊ |
317 | else buffer = gTempBlock + blockOffset;␊ |
318 | } else {␊ |
319 | offset += blockOffset;␊ |
320 | CacheRead(gCurrentIH, buffer, offset, length, 0);␊ |
321 | }␊ |
322 | ␊ |
323 | return buffer;␊ |
324 | }␊ |
325 | ␊ |
326 | static long ReadInode( long inodeNum, InodePtr inode, long * flags, long * time )␊ |
327 | {␊ |
328 | long fragNum = ino_to_fsba(gFS, inodeNum);␊ |
329 | long blockOffset = ino_to_fsbo(gFS, inodeNum) * sizeof(Inode);␊ |
330 | ␊ |
331 | ReadBlock(fragNum, blockOffset, sizeof(Inode), (char *)inode, 1);␊ |
332 | byte_swap_dinode_in(inode);␊ |
333 | ␊ |
334 | if (time != 0) *time = inode->di_mtime;␊ |
335 | ␊ |
336 | if (flags != 0) {␊ |
337 | switch (inode->di_mode & IFMT) {␊ |
338 | case IFREG: *flags = kFileTypeFlat; break;␊ |
339 | case IFDIR: *flags = kFileTypeDirectory; break;␊ |
340 | case IFLNK: *flags = kFileTypeLink; break;␊ |
341 | default : *flags = kFileTypeUnknown; break;␊ |
342 | }␊ |
343 | ␊ |
344 | *flags |= inode->di_mode & kPermMask;␊ |
345 | ␊ |
346 | if (inode->di_uid != 0) *flags |= kOwnerNotRoot;␊ |
347 | }␊ |
348 | ␊ |
349 | return 0;␊ |
350 | }␊ |
351 | ␊ |
352 | static long ResolvePathToInode( char * filePath, long * flags,␊ |
353 | InodePtr fileInode, InodePtr dirInode )␊ |
354 | {␊ |
355 | char * restPath;␊ |
356 | long ret, cnt;␊ |
357 | ␊ |
358 | // if filePath is empty the we want this directory.␊ |
359 | if (*filePath == '\0') {␊ |
360 | bcopy((char *)dirInode, (char *)fileInode, sizeof(Inode));␊ |
361 | return 0;␊ |
362 | }␊ |
363 | ␊ |
364 | // Copy the file name to gTempName␊ |
365 | cnt = 0;␊ |
366 | while ((filePath[cnt] != '/') && (filePath[cnt] != '\0')) cnt++;␊ |
367 | strlcpy(gTempName, filePath, cnt+1);␊ |
368 | ␊ |
369 | // Move restPath to the right place.␊ |
370 | if (filePath[cnt] != '\0') cnt++;␊ |
371 | restPath = filePath + cnt;␊ |
372 | ␊ |
373 | // gTempName is a name in the current Dir.␊ |
374 | // restPath is the rest of the path if any.␊ |
375 | ␊ |
376 | ret = FindFileInDir(gTempName, flags, fileInode, dirInode);␊ |
377 | if (ret == -1) return -1;␊ |
378 | ␊ |
379 | if ((*restPath != '\0') && ((*flags & kFileTypeMask) == kFileTypeDirectory))␊ |
380 | ret = ResolvePathToInode(restPath, flags, fileInode, fileInode);␊ |
381 | ␊ |
382 | return ret;␊ |
383 | }␊ |
384 | ␊ |
385 | static long ReadDirEntry( InodePtr dirInode, long * fileInodeNum,␊ |
386 | long long * dirIndex, char ** name )␊ |
387 | {␊ |
388 | struct direct *dir;␊ |
389 | char *buffer;␊ |
390 | long long index;␊ |
391 | long dirBlockNum, dirBlockOffset;␊ |
392 | ␊ |
393 | while (1) {␊ |
394 | index = *dirIndex;␊ |
395 | ␊ |
396 | dirBlockOffset = (long) (index % DIRBLKSIZ);␊ |
397 | dirBlockNum = (long) (index / DIRBLKSIZ);␊ |
398 | ␊ |
399 | buffer = ReadFileBlock(dirInode, dirBlockNum, 0, DIRBLKSIZ, 0, 1);␊ |
400 | if (buffer == 0) return -1;␊ |
401 | ␊ |
402 | dir = (struct direct *)(buffer + dirBlockOffset);␊ |
403 | byte_swap_dir_block_in((char *)dir, 1);␊ |
404 | ␊ |
405 | *dirIndex += dir->d_reclen;␊ |
406 | ␊ |
407 | if (dir->d_ino != 0) break;␊ |
408 | ␊ |
409 | if (dirBlockOffset != 0) return -1;␊ |
410 | }␊ |
411 | ␊ |
412 | *fileInodeNum = dir->d_ino;␊ |
413 | *name = strlcpy(gTempName2, dir->d_name, dir->d_namlen+1);␊ |
414 | ␊ |
415 | return 0;␊ |
416 | }␊ |
417 | ␊ |
418 | static long FindFileInDir( char * fileName, long * flags,␊ |
419 | InodePtr fileInode, InodePtr dirInode )␊ |
420 | {␊ |
421 | long ret, inodeNum;␊ |
422 | long long index = 0;␊ |
423 | char *name;␊ |
424 | ␊ |
425 | while (1) {␊ |
426 | ret = ReadDirEntry(dirInode, &inodeNum, &index, &name);␊ |
427 | if (ret == -1) return -1;␊ |
428 | ␊ |
429 | if (strcmp(fileName, name) == 0) break;␊ |
430 | }␊ |
431 | ␊ |
432 | ReadInode(inodeNum, fileInode, flags, 0);␊ |
433 | ␊ |
434 | return 0;␊ |
435 | }␊ |
436 | ␊ |
437 | static char * ReadFileBlock( InodePtr fileInode, long fragNum, long blockOffset,␊ |
438 | long length, char * buffer, long cache )␊ |
439 | {␊ |
440 | long fragCount, blockNum;␊ |
441 | long diskFragNum, indFragNum, indBlockOff, refsPerBlock;␊ |
442 | char *indBlock;␊ |
443 | ␊ |
444 | fragCount = (fileInode->di_size + gFragSize - 1) / gFragSize;␊ |
445 | if (fragNum >= fragCount) return 0;␊ |
446 | ␊ |
447 | refsPerBlock = gBlockSize / sizeof(ufs_daddr_t);␊ |
448 | ␊ |
449 | blockNum = fragNum / gFragsPerBlock;␊ |
450 | fragNum -= blockNum * gFragsPerBlock;␊ |
451 | ␊ |
452 | // Get Direct Block Number.␊ |
453 | if (blockNum < NDADDR) {␊ |
454 | diskFragNum = fileInode->di_db[blockNum];␊ |
455 | } else {␊ |
456 | blockNum -= NDADDR;␊ |
457 | ␊ |
458 | // Get Single Indirect Fragment Number.␊ |
459 | if (blockNum < refsPerBlock) {␊ |
460 | indFragNum = fileInode->di_ib[0];␊ |
461 | } else {␊ |
462 | blockNum -= refsPerBlock;␊ |
463 | ␊ |
464 | // Get Double Indirect Fragment Number.␊ |
465 | if (blockNum < (refsPerBlock * refsPerBlock)) {␊ |
466 | indFragNum = fileInode->di_ib[1];␊ |
467 | } else {␊ |
468 | blockNum -= refsPerBlock * refsPerBlock;␊ |
469 | ␊ |
470 | // Get Triple Indirect Fragment Number.␊ |
471 | indFragNum = fileInode->di_ib[2];␊ |
472 | ␊ |
473 | indBlock = ReadBlock(indFragNum, 0, gBlockSize, 0, 1);␊ |
474 | indBlockOff = blockNum / (refsPerBlock * refsPerBlock);␊ |
475 | blockNum %= (refsPerBlock * refsPerBlock);␊ |
476 | indFragNum = SWAP_BE32(((ufs_daddr_t *)indBlock)[indBlockOff]);␊ |
477 | }␊ |
478 | ␊ |
479 | indBlock = ReadBlock(indFragNum, 0, gBlockSize, 0, 1);␊ |
480 | indBlockOff = blockNum / refsPerBlock;␊ |
481 | blockNum %= refsPerBlock;␊ |
482 | indFragNum = SWAP_BE32(((ufs_daddr_t *)indBlock)[indBlockOff]);␊ |
483 | }␊ |
484 | ␊ |
485 | indBlock = ReadBlock(indFragNum, 0, gBlockSize, 0, 1);␊ |
486 | diskFragNum = SWAP_BE32(((ufs_daddr_t *)indBlock)[blockNum]);␊ |
487 | }␊ |
488 | ␊ |
489 | buffer = ReadBlock(diskFragNum+fragNum, blockOffset, length, buffer, cache);␊ |
490 | ␊ |
491 | return buffer;␊ |
492 | }␊ |
493 | ␊ |
494 | static long ReadFile( InodePtr fileInode, uint64_t * length, void * base, uint64_t offset )␊ |
495 | {␊ |
496 | long bytesLeft, curSize, curFrag;␊ |
497 | char *buffer, *curAddr = (char *)base;␊ |
498 | ␊ |
499 | bytesLeft = fileInode->di_size;␊ |
500 | ␊ |
501 | if (offset > bytesLeft) {␊ |
502 | printf("Offset is too large.\n");␊ |
503 | return -1;␊ |
504 | }␊ |
505 | ␊ |
506 | if ((*length == 0) || ((offset + *length) > bytesLeft)) {␊ |
507 | *length = bytesLeft - offset;␊ |
508 | }␊ |
509 | /*␊ |
510 | if (bytesLeft > kLoadSize) {␊ |
511 | printf("File is too large.\n");␊ |
512 | return -1;␊ |
513 | }␊ |
514 | */␊ |
515 | bytesLeft = *length;␊ |
516 | curFrag = (offset / gBlockSize) * gFragsPerBlock;␊ |
517 | offset %= gBlockSize;␊ |
518 | ␊ |
519 | while (bytesLeft) {␊ |
520 | curSize = gBlockSize;␊ |
521 | if (curSize > bytesLeft) curSize = bytesLeft;␊ |
522 | if ((offset + curSize) > gBlockSize) curSize = (gBlockSize - offset);␊ |
523 | ␊ |
524 | buffer = ReadFileBlock(fileInode, curFrag, offset, curSize, curAddr, 0);␊ |
525 | if (buffer == 0) break;␊ |
526 | ␊ |
527 | if (offset != 0) offset = 0;␊ |
528 | ␊ |
529 | curFrag += gFragsPerBlock;␊ |
530 | curAddr += curSize;␊ |
531 | bytesLeft -= curSize;␊ |
532 | }␊ |
533 | ␊ |
534 | return bytesLeft;␊ |
535 | }␊ |
536 | |