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