Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/adfs/dir_f.c | |
3 | * | |
4 | * Copyright (C) 1997-1999 Russell King | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * E and F format directory handling | |
11 | */ | |
1da177e4 | 12 | #include <linux/buffer_head.h> |
1da177e4 LT |
13 | #include "adfs.h" |
14 | #include "dir_f.h" | |
15 | ||
16 | static void adfs_f_free(struct adfs_dir *dir); | |
17 | ||
18 | /* | |
19 | * Read an (unaligned) value of length 1..4 bytes | |
20 | */ | |
21 | static inline unsigned int adfs_readval(unsigned char *p, int len) | |
22 | { | |
23 | unsigned int val = 0; | |
24 | ||
25 | switch (len) { | |
26 | case 4: val |= p[3] << 24; | |
27 | case 3: val |= p[2] << 16; | |
28 | case 2: val |= p[1] << 8; | |
29 | default: val |= p[0]; | |
30 | } | |
31 | return val; | |
32 | } | |
33 | ||
34 | static inline void adfs_writeval(unsigned char *p, int len, unsigned int val) | |
35 | { | |
36 | switch (len) { | |
37 | case 4: p[3] = val >> 24; | |
38 | case 3: p[2] = val >> 16; | |
39 | case 2: p[1] = val >> 8; | |
40 | default: p[0] = val; | |
41 | } | |
42 | } | |
43 | ||
44 | static inline int adfs_readname(char *buf, char *ptr, int maxlen) | |
45 | { | |
46 | char *old_buf = buf; | |
47 | ||
3223ea8c | 48 | while ((unsigned char)*ptr >= ' ' && maxlen--) { |
1da177e4 LT |
49 | if (*ptr == '/') |
50 | *buf++ = '.'; | |
51 | else | |
52 | *buf++ = *ptr; | |
53 | ptr++; | |
54 | } | |
55 | *buf = '\0'; | |
56 | ||
57 | return buf - old_buf; | |
58 | } | |
59 | ||
60 | #define ror13(v) ((v >> 13) | (v << 19)) | |
61 | ||
62 | #define dir_u8(idx) \ | |
63 | ({ int _buf = idx >> blocksize_bits; \ | |
64 | int _off = idx - (_buf << blocksize_bits);\ | |
65 | *(u8 *)(bh[_buf]->b_data + _off); \ | |
66 | }) | |
67 | ||
68 | #define dir_u32(idx) \ | |
69 | ({ int _buf = idx >> blocksize_bits; \ | |
70 | int _off = idx - (_buf << blocksize_bits);\ | |
71 | *(__le32 *)(bh[_buf]->b_data + _off); \ | |
72 | }) | |
73 | ||
74 | #define bufoff(_bh,_idx) \ | |
75 | ({ int _buf = _idx >> blocksize_bits; \ | |
76 | int _off = _idx - (_buf << blocksize_bits);\ | |
77 | (u8 *)(_bh[_buf]->b_data + _off); \ | |
78 | }) | |
79 | ||
80 | /* | |
81 | * There are some algorithms that are nice in | |
82 | * assembler, but a bitch in C... This is one | |
83 | * of them. | |
84 | */ | |
85 | static u8 | |
86 | adfs_dir_checkbyte(const struct adfs_dir *dir) | |
87 | { | |
88 | struct buffer_head * const *bh = dir->bh; | |
89 | const int blocksize_bits = dir->sb->s_blocksize_bits; | |
90 | union { __le32 *ptr32; u8 *ptr8; } ptr, end; | |
91 | u32 dircheck = 0; | |
92 | int last = 5 - 26; | |
93 | int i = 0; | |
94 | ||
95 | /* | |
96 | * Accumulate each word up to the last whole | |
97 | * word of the last directory entry. This | |
98 | * can spread across several buffer heads. | |
99 | */ | |
100 | do { | |
101 | last += 26; | |
102 | do { | |
103 | dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck); | |
104 | ||
105 | i += sizeof(u32); | |
106 | } while (i < (last & ~3)); | |
107 | } while (dir_u8(last) != 0); | |
108 | ||
109 | /* | |
110 | * Accumulate the last few bytes. These | |
111 | * bytes will be within the same bh. | |
112 | */ | |
113 | if (i != last) { | |
114 | ptr.ptr8 = bufoff(bh, i); | |
115 | end.ptr8 = ptr.ptr8 + last - i; | |
116 | ||
e5949050 | 117 | do { |
1da177e4 | 118 | dircheck = *ptr.ptr8++ ^ ror13(dircheck); |
e5949050 | 119 | } while (ptr.ptr8 < end.ptr8); |
1da177e4 LT |
120 | } |
121 | ||
122 | /* | |
123 | * The directory tail is in the final bh | |
124 | * Note that contary to the RISC OS PRMs, | |
125 | * the first few bytes are NOT included | |
126 | * in the check. All bytes are in the | |
127 | * same bh. | |
128 | */ | |
129 | ptr.ptr8 = bufoff(bh, 2008); | |
130 | end.ptr8 = ptr.ptr8 + 36; | |
131 | ||
132 | do { | |
133 | __le32 v = *ptr.ptr32++; | |
134 | dircheck = le32_to_cpu(v) ^ ror13(dircheck); | |
135 | } while (ptr.ptr32 < end.ptr32); | |
136 | ||
137 | return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff; | |
138 | } | |
139 | ||
140 | /* | |
141 | * Read and check that a directory is valid | |
142 | */ | |
143 | static int | |
144 | adfs_dir_read(struct super_block *sb, unsigned long object_id, | |
145 | unsigned int size, struct adfs_dir *dir) | |
146 | { | |
147 | const unsigned int blocksize_bits = sb->s_blocksize_bits; | |
148 | int blk = 0; | |
149 | ||
150 | /* | |
151 | * Directories which are not a multiple of 2048 bytes | |
152 | * are considered bad v2 [3.6] | |
153 | */ | |
154 | if (size & 2047) | |
155 | goto bad_dir; | |
156 | ||
157 | size >>= blocksize_bits; | |
158 | ||
159 | dir->nr_buffers = 0; | |
160 | dir->sb = sb; | |
161 | ||
162 | for (blk = 0; blk < size; blk++) { | |
163 | int phys; | |
164 | ||
165 | phys = __adfs_block_map(sb, object_id, blk); | |
166 | if (!phys) { | |
167 | adfs_error(sb, "dir object %lX has a hole at offset %d", | |
168 | object_id, blk); | |
169 | goto release_buffers; | |
170 | } | |
171 | ||
172 | dir->bh[blk] = sb_bread(sb, phys); | |
173 | if (!dir->bh[blk]) | |
174 | goto release_buffers; | |
175 | } | |
176 | ||
177 | memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead)); | |
178 | memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail)); | |
179 | ||
180 | if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq || | |
181 | memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4)) | |
182 | goto bad_dir; | |
183 | ||
184 | if (memcmp(&dir->dirhead.startname, "Nick", 4) && | |
185 | memcmp(&dir->dirhead.startname, "Hugo", 4)) | |
186 | goto bad_dir; | |
187 | ||
188 | if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte) | |
189 | goto bad_dir; | |
190 | ||
191 | dir->nr_buffers = blk; | |
192 | ||
193 | return 0; | |
194 | ||
195 | bad_dir: | |
196 | adfs_error(sb, "corrupted directory fragment %lX", | |
197 | object_id); | |
198 | release_buffers: | |
199 | for (blk -= 1; blk >= 0; blk -= 1) | |
200 | brelse(dir->bh[blk]); | |
201 | ||
202 | dir->sb = NULL; | |
203 | ||
204 | return -EIO; | |
205 | } | |
206 | ||
207 | /* | |
208 | * convert a disk-based directory entry to a Linux ADFS directory entry | |
209 | */ | |
210 | static inline void | |
211 | adfs_dir2obj(struct object_info *obj, struct adfs_direntry *de) | |
212 | { | |
213 | obj->name_len = adfs_readname(obj->name, de->dirobname, ADFS_F_NAME_LEN); | |
214 | obj->file_id = adfs_readval(de->dirinddiscadd, 3); | |
215 | obj->loadaddr = adfs_readval(de->dirload, 4); | |
216 | obj->execaddr = adfs_readval(de->direxec, 4); | |
217 | obj->size = adfs_readval(de->dirlen, 4); | |
218 | obj->attr = de->newdiratts; | |
219 | } | |
220 | ||
221 | /* | |
222 | * convert a Linux ADFS directory entry to a disk-based directory entry | |
223 | */ | |
224 | static inline void | |
225 | adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj) | |
226 | { | |
227 | adfs_writeval(de->dirinddiscadd, 3, obj->file_id); | |
228 | adfs_writeval(de->dirload, 4, obj->loadaddr); | |
229 | adfs_writeval(de->direxec, 4, obj->execaddr); | |
230 | adfs_writeval(de->dirlen, 4, obj->size); | |
231 | de->newdiratts = obj->attr; | |
232 | } | |
233 | ||
234 | /* | |
235 | * get a directory entry. Note that the caller is responsible | |
236 | * for holding the relevant locks. | |
237 | */ | |
238 | static int | |
239 | __adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj) | |
240 | { | |
241 | struct super_block *sb = dir->sb; | |
242 | struct adfs_direntry de; | |
243 | int thissize, buffer, offset; | |
244 | ||
245 | buffer = pos >> sb->s_blocksize_bits; | |
246 | ||
247 | if (buffer > dir->nr_buffers) | |
248 | return -EINVAL; | |
249 | ||
250 | offset = pos & (sb->s_blocksize - 1); | |
251 | thissize = sb->s_blocksize - offset; | |
252 | if (thissize > 26) | |
253 | thissize = 26; | |
254 | ||
255 | memcpy(&de, dir->bh[buffer]->b_data + offset, thissize); | |
256 | if (thissize != 26) | |
257 | memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data, | |
258 | 26 - thissize); | |
259 | ||
260 | if (!de.dirobname[0]) | |
261 | return -ENOENT; | |
262 | ||
263 | adfs_dir2obj(obj, &de); | |
264 | ||
265 | return 0; | |
266 | } | |
267 | ||
268 | static int | |
269 | __adfs_dir_put(struct adfs_dir *dir, int pos, struct object_info *obj) | |
270 | { | |
271 | struct super_block *sb = dir->sb; | |
272 | struct adfs_direntry de; | |
273 | int thissize, buffer, offset; | |
274 | ||
275 | buffer = pos >> sb->s_blocksize_bits; | |
276 | ||
277 | if (buffer > dir->nr_buffers) | |
278 | return -EINVAL; | |
279 | ||
280 | offset = pos & (sb->s_blocksize - 1); | |
281 | thissize = sb->s_blocksize - offset; | |
282 | if (thissize > 26) | |
283 | thissize = 26; | |
284 | ||
285 | /* | |
286 | * Get the entry in total | |
287 | */ | |
288 | memcpy(&de, dir->bh[buffer]->b_data + offset, thissize); | |
289 | if (thissize != 26) | |
290 | memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data, | |
291 | 26 - thissize); | |
292 | ||
293 | /* | |
294 | * update it | |
295 | */ | |
296 | adfs_obj2dir(&de, obj); | |
297 | ||
298 | /* | |
299 | * Put the new entry back | |
300 | */ | |
301 | memcpy(dir->bh[buffer]->b_data + offset, &de, thissize); | |
302 | if (thissize != 26) | |
303 | memcpy(dir->bh[buffer + 1]->b_data, ((char *)&de) + thissize, | |
304 | 26 - thissize); | |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
309 | /* | |
310 | * the caller is responsible for holding the necessary | |
311 | * locks. | |
312 | */ | |
313 | static int | |
314 | adfs_dir_find_entry(struct adfs_dir *dir, unsigned long object_id) | |
315 | { | |
316 | int pos, ret; | |
317 | ||
318 | ret = -ENOENT; | |
319 | ||
320 | for (pos = 5; pos < ADFS_NUM_DIR_ENTRIES * 26 + 5; pos += 26) { | |
321 | struct object_info obj; | |
322 | ||
323 | if (!__adfs_dir_get(dir, pos, &obj)) | |
324 | break; | |
325 | ||
326 | if (obj.file_id == object_id) { | |
327 | ret = pos; | |
328 | break; | |
329 | } | |
330 | } | |
331 | ||
332 | return ret; | |
333 | } | |
334 | ||
335 | static int | |
336 | adfs_f_read(struct super_block *sb, unsigned int id, unsigned int sz, struct adfs_dir *dir) | |
337 | { | |
338 | int ret; | |
339 | ||
340 | if (sz != ADFS_NEWDIR_SIZE) | |
341 | return -EIO; | |
342 | ||
343 | ret = adfs_dir_read(sb, id, sz, dir); | |
344 | if (ret) | |
345 | adfs_error(sb, "unable to read directory"); | |
346 | else | |
347 | dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3); | |
348 | ||
349 | return ret; | |
350 | } | |
351 | ||
352 | static int | |
353 | adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos) | |
354 | { | |
355 | if (fpos >= ADFS_NUM_DIR_ENTRIES) | |
356 | return -ENOENT; | |
357 | ||
358 | dir->pos = 5 + fpos * 26; | |
359 | return 0; | |
360 | } | |
361 | ||
362 | static int | |
363 | adfs_f_getnext(struct adfs_dir *dir, struct object_info *obj) | |
364 | { | |
365 | unsigned int ret; | |
366 | ||
367 | ret = __adfs_dir_get(dir, dir->pos, obj); | |
368 | if (ret == 0) | |
369 | dir->pos += 26; | |
370 | ||
371 | return ret; | |
372 | } | |
373 | ||
374 | static int | |
375 | adfs_f_update(struct adfs_dir *dir, struct object_info *obj) | |
376 | { | |
377 | struct super_block *sb = dir->sb; | |
378 | int ret, i; | |
379 | ||
380 | ret = adfs_dir_find_entry(dir, obj->file_id); | |
381 | if (ret < 0) { | |
382 | adfs_error(dir->sb, "unable to locate entry to update"); | |
383 | goto out; | |
384 | } | |
385 | ||
386 | __adfs_dir_put(dir, ret, obj); | |
387 | ||
388 | /* | |
389 | * Increment directory sequence number | |
390 | */ | |
391 | dir->bh[0]->b_data[0] += 1; | |
392 | dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1; | |
393 | ||
394 | ret = adfs_dir_checkbyte(dir); | |
395 | /* | |
396 | * Update directory check byte | |
397 | */ | |
398 | dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret; | |
399 | ||
400 | #if 1 | |
401 | { | |
402 | const unsigned int blocksize_bits = sb->s_blocksize_bits; | |
403 | ||
404 | memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead)); | |
405 | memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail)); | |
406 | ||
407 | if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq || | |
408 | memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4)) | |
409 | goto bad_dir; | |
410 | ||
411 | if (memcmp(&dir->dirhead.startname, "Nick", 4) && | |
412 | memcmp(&dir->dirhead.startname, "Hugo", 4)) | |
413 | goto bad_dir; | |
414 | ||
415 | if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte) | |
416 | goto bad_dir; | |
417 | } | |
418 | #endif | |
419 | for (i = dir->nr_buffers - 1; i >= 0; i--) | |
420 | mark_buffer_dirty(dir->bh[i]); | |
421 | ||
422 | ret = 0; | |
423 | out: | |
424 | return ret; | |
425 | #if 1 | |
426 | bad_dir: | |
427 | adfs_error(dir->sb, "whoops! I broke a directory!"); | |
428 | return -EIO; | |
429 | #endif | |
430 | } | |
431 | ||
ffdc9064 AV |
432 | static int |
433 | adfs_f_sync(struct adfs_dir *dir) | |
434 | { | |
435 | int err = 0; | |
436 | int i; | |
437 | ||
438 | for (i = dir->nr_buffers - 1; i >= 0; i--) { | |
439 | struct buffer_head *bh = dir->bh[i]; | |
440 | sync_dirty_buffer(bh); | |
441 | if (buffer_req(bh) && !buffer_uptodate(bh)) | |
442 | err = -EIO; | |
443 | } | |
444 | ||
445 | return err; | |
446 | } | |
447 | ||
1da177e4 LT |
448 | static void |
449 | adfs_f_free(struct adfs_dir *dir) | |
450 | { | |
451 | int i; | |
452 | ||
453 | for (i = dir->nr_buffers - 1; i >= 0; i--) { | |
454 | brelse(dir->bh[i]); | |
455 | dir->bh[i] = NULL; | |
456 | } | |
457 | ||
458 | dir->nr_buffers = 0; | |
459 | dir->sb = NULL; | |
460 | } | |
461 | ||
462 | struct adfs_dir_ops adfs_f_dir_ops = { | |
463 | .read = adfs_f_read, | |
464 | .setpos = adfs_f_setpos, | |
465 | .getnext = adfs_f_getnext, | |
466 | .update = adfs_f_update, | |
ffdc9064 | 467 | .sync = adfs_f_sync, |
1da177e4 LT |
468 | .free = adfs_f_free |
469 | }; |