Commit | Line | Data |
---|---|---|
d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/fs/adfs/dir_f.c | |
4 | * | |
5 | * Copyright (C) 1997-1999 Russell King | |
6 | * | |
1da177e4 LT |
7 | * E and F format directory handling |
8 | */ | |
1da177e4 LT |
9 | #include "adfs.h" |
10 | #include "dir_f.h" | |
11 | ||
12 | static void adfs_f_free(struct adfs_dir *dir); | |
13 | ||
14 | /* | |
15 | * Read an (unaligned) value of length 1..4 bytes | |
16 | */ | |
17 | static inline unsigned int adfs_readval(unsigned char *p, int len) | |
18 | { | |
19 | unsigned int val = 0; | |
20 | ||
21 | switch (len) { | |
22 | case 4: val |= p[3] << 24; | |
74f79099 | 23 | /* fall through */ |
1da177e4 | 24 | case 3: val |= p[2] << 16; |
74f79099 | 25 | /* fall through */ |
1da177e4 | 26 | case 2: val |= p[1] << 8; |
74f79099 | 27 | /* fall through */ |
1da177e4 LT |
28 | default: val |= p[0]; |
29 | } | |
30 | return val; | |
31 | } | |
32 | ||
33 | static inline void adfs_writeval(unsigned char *p, int len, unsigned int val) | |
34 | { | |
35 | switch (len) { | |
36 | case 4: p[3] = val >> 24; | |
74f79099 | 37 | /* fall through */ |
1da177e4 | 38 | case 3: p[2] = val >> 16; |
74f79099 | 39 | /* fall through */ |
1da177e4 | 40 | case 2: p[1] = val >> 8; |
74f79099 | 41 | /* fall through */ |
1da177e4 LT |
42 | default: p[0] = val; |
43 | } | |
44 | } | |
45 | ||
1da177e4 LT |
46 | #define ror13(v) ((v >> 13) | (v << 19)) |
47 | ||
48 | #define dir_u8(idx) \ | |
49 | ({ int _buf = idx >> blocksize_bits; \ | |
50 | int _off = idx - (_buf << blocksize_bits);\ | |
51 | *(u8 *)(bh[_buf]->b_data + _off); \ | |
52 | }) | |
53 | ||
54 | #define dir_u32(idx) \ | |
55 | ({ int _buf = idx >> blocksize_bits; \ | |
56 | int _off = idx - (_buf << blocksize_bits);\ | |
57 | *(__le32 *)(bh[_buf]->b_data + _off); \ | |
58 | }) | |
59 | ||
60 | #define bufoff(_bh,_idx) \ | |
61 | ({ int _buf = _idx >> blocksize_bits; \ | |
62 | int _off = _idx - (_buf << blocksize_bits);\ | |
63 | (u8 *)(_bh[_buf]->b_data + _off); \ | |
64 | }) | |
65 | ||
66 | /* | |
67 | * There are some algorithms that are nice in | |
68 | * assembler, but a bitch in C... This is one | |
69 | * of them. | |
70 | */ | |
71 | static u8 | |
72 | adfs_dir_checkbyte(const struct adfs_dir *dir) | |
73 | { | |
74 | struct buffer_head * const *bh = dir->bh; | |
75 | const int blocksize_bits = dir->sb->s_blocksize_bits; | |
76 | union { __le32 *ptr32; u8 *ptr8; } ptr, end; | |
77 | u32 dircheck = 0; | |
78 | int last = 5 - 26; | |
79 | int i = 0; | |
80 | ||
81 | /* | |
82 | * Accumulate each word up to the last whole | |
83 | * word of the last directory entry. This | |
84 | * can spread across several buffer heads. | |
85 | */ | |
86 | do { | |
87 | last += 26; | |
88 | do { | |
89 | dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck); | |
90 | ||
91 | i += sizeof(u32); | |
92 | } while (i < (last & ~3)); | |
93 | } while (dir_u8(last) != 0); | |
94 | ||
95 | /* | |
96 | * Accumulate the last few bytes. These | |
97 | * bytes will be within the same bh. | |
98 | */ | |
99 | if (i != last) { | |
100 | ptr.ptr8 = bufoff(bh, i); | |
101 | end.ptr8 = ptr.ptr8 + last - i; | |
102 | ||
e5949050 | 103 | do { |
1da177e4 | 104 | dircheck = *ptr.ptr8++ ^ ror13(dircheck); |
e5949050 | 105 | } while (ptr.ptr8 < end.ptr8); |
1da177e4 LT |
106 | } |
107 | ||
108 | /* | |
109 | * The directory tail is in the final bh | |
110 | * Note that contary to the RISC OS PRMs, | |
111 | * the first few bytes are NOT included | |
112 | * in the check. All bytes are in the | |
113 | * same bh. | |
114 | */ | |
115 | ptr.ptr8 = bufoff(bh, 2008); | |
116 | end.ptr8 = ptr.ptr8 + 36; | |
117 | ||
118 | do { | |
119 | __le32 v = *ptr.ptr32++; | |
120 | dircheck = le32_to_cpu(v) ^ ror13(dircheck); | |
121 | } while (ptr.ptr32 < end.ptr32); | |
122 | ||
123 | return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff; | |
124 | } | |
125 | ||
5ed70bb4 RK |
126 | /* Read and check that a directory is valid */ |
127 | static int adfs_dir_read(struct super_block *sb, u32 indaddr, | |
128 | unsigned int size, struct adfs_dir *dir) | |
1da177e4 LT |
129 | { |
130 | const unsigned int blocksize_bits = sb->s_blocksize_bits; | |
131 | int blk = 0; | |
132 | ||
133 | /* | |
134 | * Directories which are not a multiple of 2048 bytes | |
135 | * are considered bad v2 [3.6] | |
136 | */ | |
137 | if (size & 2047) | |
138 | goto bad_dir; | |
139 | ||
140 | size >>= blocksize_bits; | |
141 | ||
142 | dir->nr_buffers = 0; | |
143 | dir->sb = sb; | |
144 | ||
145 | for (blk = 0; blk < size; blk++) { | |
146 | int phys; | |
147 | ||
5ed70bb4 | 148 | phys = __adfs_block_map(sb, indaddr, blk); |
1da177e4 | 149 | if (!phys) { |
5ed70bb4 RK |
150 | adfs_error(sb, "dir %06x has a hole at offset %d", |
151 | indaddr, blk); | |
1da177e4 LT |
152 | goto release_buffers; |
153 | } | |
154 | ||
155 | dir->bh[blk] = sb_bread(sb, phys); | |
156 | if (!dir->bh[blk]) | |
157 | goto release_buffers; | |
158 | } | |
159 | ||
160 | memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead)); | |
161 | memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail)); | |
162 | ||
163 | if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq || | |
164 | memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4)) | |
165 | goto bad_dir; | |
166 | ||
167 | if (memcmp(&dir->dirhead.startname, "Nick", 4) && | |
168 | memcmp(&dir->dirhead.startname, "Hugo", 4)) | |
169 | goto bad_dir; | |
170 | ||
171 | if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte) | |
172 | goto bad_dir; | |
173 | ||
174 | dir->nr_buffers = blk; | |
175 | ||
176 | return 0; | |
177 | ||
178 | bad_dir: | |
5ed70bb4 | 179 | adfs_error(sb, "dir %06x is corrupted", indaddr); |
1da177e4 LT |
180 | release_buffers: |
181 | for (blk -= 1; blk >= 0; blk -= 1) | |
182 | brelse(dir->bh[blk]); | |
183 | ||
184 | dir->sb = NULL; | |
185 | ||
186 | return -EIO; | |
187 | } | |
188 | ||
189 | /* | |
190 | * convert a disk-based directory entry to a Linux ADFS directory entry | |
191 | */ | |
192 | static inline void | |
da23ef05 SS |
193 | adfs_dir2obj(struct adfs_dir *dir, struct object_info *obj, |
194 | struct adfs_direntry *de) | |
1da177e4 | 195 | { |
adb514a4 RK |
196 | unsigned int name_len; |
197 | ||
198 | for (name_len = 0; name_len < ADFS_F_NAME_LEN; name_len++) { | |
199 | if (de->dirobname[name_len] < ' ') | |
200 | break; | |
201 | ||
202 | obj->name[name_len] = de->dirobname[name_len]; | |
203 | } | |
204 | ||
205 | obj->name_len = name_len; | |
5ed70bb4 | 206 | obj->indaddr = adfs_readval(de->dirinddiscadd, 3); |
1da177e4 LT |
207 | obj->loadaddr = adfs_readval(de->dirload, 4); |
208 | obj->execaddr = adfs_readval(de->direxec, 4); | |
209 | obj->size = adfs_readval(de->dirlen, 4); | |
210 | obj->attr = de->newdiratts; | |
da23ef05 | 211 | |
411c49bc | 212 | adfs_object_fixup(dir, obj); |
1da177e4 LT |
213 | } |
214 | ||
215 | /* | |
216 | * convert a Linux ADFS directory entry to a disk-based directory entry | |
217 | */ | |
218 | static inline void | |
219 | adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj) | |
220 | { | |
5ed70bb4 | 221 | adfs_writeval(de->dirinddiscadd, 3, obj->indaddr); |
1da177e4 LT |
222 | adfs_writeval(de->dirload, 4, obj->loadaddr); |
223 | adfs_writeval(de->direxec, 4, obj->execaddr); | |
224 | adfs_writeval(de->dirlen, 4, obj->size); | |
225 | de->newdiratts = obj->attr; | |
226 | } | |
227 | ||
228 | /* | |
229 | * get a directory entry. Note that the caller is responsible | |
230 | * for holding the relevant locks. | |
231 | */ | |
232 | static int | |
233 | __adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj) | |
234 | { | |
235 | struct super_block *sb = dir->sb; | |
236 | struct adfs_direntry de; | |
237 | int thissize, buffer, offset; | |
238 | ||
239 | buffer = pos >> sb->s_blocksize_bits; | |
240 | ||
241 | if (buffer > dir->nr_buffers) | |
242 | return -EINVAL; | |
243 | ||
244 | offset = pos & (sb->s_blocksize - 1); | |
245 | thissize = sb->s_blocksize - offset; | |
246 | if (thissize > 26) | |
247 | thissize = 26; | |
248 | ||
249 | memcpy(&de, dir->bh[buffer]->b_data + offset, thissize); | |
250 | if (thissize != 26) | |
251 | memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data, | |
252 | 26 - thissize); | |
253 | ||
254 | if (!de.dirobname[0]) | |
255 | return -ENOENT; | |
256 | ||
da23ef05 | 257 | adfs_dir2obj(dir, obj, &de); |
1da177e4 LT |
258 | |
259 | return 0; | |
260 | } | |
261 | ||
262 | static int | |
263 | __adfs_dir_put(struct adfs_dir *dir, int pos, struct object_info *obj) | |
264 | { | |
265 | struct super_block *sb = dir->sb; | |
266 | struct adfs_direntry de; | |
267 | int thissize, buffer, offset; | |
268 | ||
269 | buffer = pos >> sb->s_blocksize_bits; | |
270 | ||
271 | if (buffer > dir->nr_buffers) | |
272 | return -EINVAL; | |
273 | ||
274 | offset = pos & (sb->s_blocksize - 1); | |
275 | thissize = sb->s_blocksize - offset; | |
276 | if (thissize > 26) | |
277 | thissize = 26; | |
278 | ||
279 | /* | |
280 | * Get the entry in total | |
281 | */ | |
282 | memcpy(&de, dir->bh[buffer]->b_data + offset, thissize); | |
283 | if (thissize != 26) | |
284 | memcpy(((char *)&de) + thissize, dir->bh[buffer + 1]->b_data, | |
285 | 26 - thissize); | |
286 | ||
287 | /* | |
288 | * update it | |
289 | */ | |
290 | adfs_obj2dir(&de, obj); | |
291 | ||
292 | /* | |
293 | * Put the new entry back | |
294 | */ | |
295 | memcpy(dir->bh[buffer]->b_data + offset, &de, thissize); | |
296 | if (thissize != 26) | |
297 | memcpy(dir->bh[buffer + 1]->b_data, ((char *)&de) + thissize, | |
298 | 26 - thissize); | |
299 | ||
300 | return 0; | |
301 | } | |
302 | ||
303 | /* | |
304 | * the caller is responsible for holding the necessary | |
305 | * locks. | |
306 | */ | |
5ed70bb4 | 307 | static int adfs_dir_find_entry(struct adfs_dir *dir, u32 indaddr) |
1da177e4 LT |
308 | { |
309 | int pos, ret; | |
310 | ||
311 | ret = -ENOENT; | |
312 | ||
313 | for (pos = 5; pos < ADFS_NUM_DIR_ENTRIES * 26 + 5; pos += 26) { | |
314 | struct object_info obj; | |
315 | ||
316 | if (!__adfs_dir_get(dir, pos, &obj)) | |
317 | break; | |
318 | ||
5ed70bb4 | 319 | if (obj.indaddr == indaddr) { |
1da177e4 LT |
320 | ret = pos; |
321 | break; | |
322 | } | |
323 | } | |
324 | ||
325 | return ret; | |
326 | } | |
327 | ||
5ed70bb4 RK |
328 | static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size, |
329 | struct adfs_dir *dir) | |
1da177e4 LT |
330 | { |
331 | int ret; | |
332 | ||
5ed70bb4 | 333 | if (size != ADFS_NEWDIR_SIZE) |
1da177e4 LT |
334 | return -EIO; |
335 | ||
5ed70bb4 | 336 | ret = adfs_dir_read(sb, indaddr, size, dir); |
1da177e4 LT |
337 | if (ret) |
338 | adfs_error(sb, "unable to read directory"); | |
339 | else | |
340 | dir->parent_id = adfs_readval(dir->dirtail.new.dirparent, 3); | |
341 | ||
342 | return ret; | |
343 | } | |
344 | ||
345 | static int | |
346 | adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos) | |
347 | { | |
348 | if (fpos >= ADFS_NUM_DIR_ENTRIES) | |
349 | return -ENOENT; | |
350 | ||
351 | dir->pos = 5 + fpos * 26; | |
352 | return 0; | |
353 | } | |
354 | ||
355 | static int | |
356 | adfs_f_getnext(struct adfs_dir *dir, struct object_info *obj) | |
357 | { | |
358 | unsigned int ret; | |
359 | ||
360 | ret = __adfs_dir_get(dir, dir->pos, obj); | |
361 | if (ret == 0) | |
362 | dir->pos += 26; | |
363 | ||
364 | return ret; | |
365 | } | |
366 | ||
367 | static int | |
368 | adfs_f_update(struct adfs_dir *dir, struct object_info *obj) | |
369 | { | |
370 | struct super_block *sb = dir->sb; | |
371 | int ret, i; | |
372 | ||
5ed70bb4 | 373 | ret = adfs_dir_find_entry(dir, obj->indaddr); |
1da177e4 LT |
374 | if (ret < 0) { |
375 | adfs_error(dir->sb, "unable to locate entry to update"); | |
376 | goto out; | |
377 | } | |
378 | ||
379 | __adfs_dir_put(dir, ret, obj); | |
380 | ||
381 | /* | |
382 | * Increment directory sequence number | |
383 | */ | |
384 | dir->bh[0]->b_data[0] += 1; | |
385 | dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 6] += 1; | |
386 | ||
387 | ret = adfs_dir_checkbyte(dir); | |
388 | /* | |
389 | * Update directory check byte | |
390 | */ | |
391 | dir->bh[dir->nr_buffers - 1]->b_data[sb->s_blocksize - 1] = ret; | |
392 | ||
393 | #if 1 | |
394 | { | |
395 | const unsigned int blocksize_bits = sb->s_blocksize_bits; | |
396 | ||
397 | memcpy(&dir->dirhead, bufoff(dir->bh, 0), sizeof(dir->dirhead)); | |
398 | memcpy(&dir->dirtail, bufoff(dir->bh, 2007), sizeof(dir->dirtail)); | |
399 | ||
400 | if (dir->dirhead.startmasseq != dir->dirtail.new.endmasseq || | |
401 | memcmp(&dir->dirhead.startname, &dir->dirtail.new.endname, 4)) | |
402 | goto bad_dir; | |
403 | ||
404 | if (memcmp(&dir->dirhead.startname, "Nick", 4) && | |
405 | memcmp(&dir->dirhead.startname, "Hugo", 4)) | |
406 | goto bad_dir; | |
407 | ||
408 | if (adfs_dir_checkbyte(dir) != dir->dirtail.new.dircheckbyte) | |
409 | goto bad_dir; | |
410 | } | |
411 | #endif | |
412 | for (i = dir->nr_buffers - 1; i >= 0; i--) | |
413 | mark_buffer_dirty(dir->bh[i]); | |
414 | ||
415 | ret = 0; | |
416 | out: | |
417 | return ret; | |
418 | #if 1 | |
419 | bad_dir: | |
420 | adfs_error(dir->sb, "whoops! I broke a directory!"); | |
421 | return -EIO; | |
422 | #endif | |
423 | } | |
424 | ||
ffdc9064 AV |
425 | static int |
426 | adfs_f_sync(struct adfs_dir *dir) | |
427 | { | |
428 | int err = 0; | |
429 | int i; | |
430 | ||
431 | for (i = dir->nr_buffers - 1; i >= 0; i--) { | |
432 | struct buffer_head *bh = dir->bh[i]; | |
433 | sync_dirty_buffer(bh); | |
434 | if (buffer_req(bh) && !buffer_uptodate(bh)) | |
435 | err = -EIO; | |
436 | } | |
437 | ||
438 | return err; | |
439 | } | |
440 | ||
1da177e4 LT |
441 | static void |
442 | adfs_f_free(struct adfs_dir *dir) | |
443 | { | |
444 | int i; | |
445 | ||
446 | for (i = dir->nr_buffers - 1; i >= 0; i--) { | |
447 | brelse(dir->bh[i]); | |
448 | dir->bh[i] = NULL; | |
449 | } | |
450 | ||
451 | dir->nr_buffers = 0; | |
452 | dir->sb = NULL; | |
453 | } | |
454 | ||
0125f504 | 455 | const struct adfs_dir_ops adfs_f_dir_ops = { |
1da177e4 LT |
456 | .read = adfs_f_read, |
457 | .setpos = adfs_f_setpos, | |
458 | .getnext = adfs_f_getnext, | |
459 | .update = adfs_f_update, | |
ffdc9064 | 460 | .sync = adfs_f_sync, |
1da177e4 LT |
461 | .free = adfs_f_free |
462 | }; |