1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/fs/adfs/dir.c |
4 | * |
5 | * Copyright (C) 1999-2000 Russell King |
6 | * |
7 | * Common directory handling for ADFS |
8 | */ |
9 | #include <linux/slab.h> |
10 | #include "adfs.h" |
11 | |
12 | /* |
13 | * For future. This should probably be per-directory. |
14 | */ |
15 | static DECLARE_RWSEM(adfs_dir_rwsem); |
16 | |
17 | int adfs_dir_copyfrom(void *dst, struct adfs_dir *dir, unsigned int offset, |
18 | size_t len) |
19 | { |
20 | struct super_block *sb = dir->sb; |
21 | unsigned int index, remain; |
22 | |
23 | index = offset >> sb->s_blocksize_bits; |
24 | offset &= sb->s_blocksize - 1; |
25 | remain = sb->s_blocksize - offset; |
26 | if (index + (remain < len) >= dir->nr_buffers) |
27 | return -EINVAL; |
28 | |
29 | if (remain < len) { |
30 | memcpy(dst, dir->bhs[index]->b_data + offset, remain); |
31 | dst += remain; |
32 | len -= remain; |
33 | index += 1; |
34 | offset = 0; |
35 | } |
36 | |
37 | memcpy(dst, dir->bhs[index]->b_data + offset, len); |
38 | |
39 | return 0; |
40 | } |
41 | |
42 | int adfs_dir_copyto(struct adfs_dir *dir, unsigned int offset, const void *src, |
43 | size_t len) |
44 | { |
45 | struct super_block *sb = dir->sb; |
46 | unsigned int index, remain; |
47 | |
48 | index = offset >> sb->s_blocksize_bits; |
49 | offset &= sb->s_blocksize - 1; |
50 | remain = sb->s_blocksize - offset; |
51 | if (index + (remain < len) >= dir->nr_buffers) |
52 | return -EINVAL; |
53 | |
54 | if (remain < len) { |
55 | memcpy(dir->bhs[index]->b_data + offset, src, remain); |
56 | src += remain; |
57 | len -= remain; |
58 | index += 1; |
59 | offset = 0; |
60 | } |
61 | |
62 | memcpy(dir->bhs[index]->b_data + offset, src, len); |
63 | |
64 | return 0; |
65 | } |
66 | |
67 | static void __adfs_dir_cleanup(struct adfs_dir *dir) |
68 | { |
69 | dir->nr_buffers = 0; |
70 | |
71 | if (dir->bhs != dir->bh) |
72 | kfree(objp: dir->bhs); |
73 | dir->bhs = NULL; |
74 | dir->sb = NULL; |
75 | } |
76 | |
77 | void adfs_dir_relse(struct adfs_dir *dir) |
78 | { |
79 | unsigned int i; |
80 | |
81 | for (i = 0; i < dir->nr_buffers; i++) |
82 | brelse(bh: dir->bhs[i]); |
83 | |
84 | __adfs_dir_cleanup(dir); |
85 | } |
86 | |
87 | static void adfs_dir_forget(struct adfs_dir *dir) |
88 | { |
89 | unsigned int i; |
90 | |
91 | for (i = 0; i < dir->nr_buffers; i++) |
92 | bforget(bh: dir->bhs[i]); |
93 | |
94 | __adfs_dir_cleanup(dir); |
95 | } |
96 | |
97 | int adfs_dir_read_buffers(struct super_block *sb, u32 indaddr, |
98 | unsigned int size, struct adfs_dir *dir) |
99 | { |
100 | struct buffer_head **bhs; |
101 | unsigned int i, num; |
102 | int block; |
103 | |
104 | num = ALIGN(size, sb->s_blocksize) >> sb->s_blocksize_bits; |
105 | if (num > ARRAY_SIZE(dir->bh)) { |
106 | /* We only allow one extension */ |
107 | if (dir->bhs != dir->bh) |
108 | return -EINVAL; |
109 | |
110 | bhs = kcalloc(n: num, size: sizeof(*bhs), GFP_KERNEL); |
111 | if (!bhs) |
112 | return -ENOMEM; |
113 | |
114 | if (dir->nr_buffers) |
115 | memcpy(bhs, dir->bhs, dir->nr_buffers * sizeof(*bhs)); |
116 | |
117 | dir->bhs = bhs; |
118 | } |
119 | |
120 | for (i = dir->nr_buffers; i < num; i++) { |
121 | block = __adfs_block_map(sb, indaddr, block: i); |
122 | if (!block) { |
123 | adfs_error(sb, "dir %06x has a hole at offset %u" , |
124 | indaddr, i); |
125 | goto error; |
126 | } |
127 | |
128 | dir->bhs[i] = sb_bread(sb, block); |
129 | if (!dir->bhs[i]) { |
130 | adfs_error(sb, |
131 | "dir %06x failed read at offset %u, mapped block 0x%08x" , |
132 | indaddr, i, block); |
133 | goto error; |
134 | } |
135 | |
136 | dir->nr_buffers++; |
137 | } |
138 | return 0; |
139 | |
140 | error: |
141 | adfs_dir_relse(dir); |
142 | |
143 | return -EIO; |
144 | } |
145 | |
146 | static int adfs_dir_read(struct super_block *sb, u32 indaddr, |
147 | unsigned int size, struct adfs_dir *dir) |
148 | { |
149 | dir->sb = sb; |
150 | dir->bhs = dir->bh; |
151 | dir->nr_buffers = 0; |
152 | |
153 | return ADFS_SB(sb)->s_dir->read(sb, indaddr, size, dir); |
154 | } |
155 | |
156 | static int adfs_dir_read_inode(struct super_block *sb, struct inode *inode, |
157 | struct adfs_dir *dir) |
158 | { |
159 | int ret; |
160 | |
161 | ret = adfs_dir_read(sb, indaddr: ADFS_I(inode)->indaddr, size: inode->i_size, dir); |
162 | if (ret) |
163 | return ret; |
164 | |
165 | if (ADFS_I(inode)->parent_id != dir->parent_id) { |
166 | adfs_error(sb, |
167 | "parent directory id changed under me! (%06x but got %06x)\n" , |
168 | ADFS_I(inode)->parent_id, dir->parent_id); |
169 | adfs_dir_relse(dir); |
170 | ret = -EIO; |
171 | } |
172 | |
173 | return ret; |
174 | } |
175 | |
176 | static void adfs_dir_mark_dirty(struct adfs_dir *dir) |
177 | { |
178 | unsigned int i; |
179 | |
180 | /* Mark the buffers dirty */ |
181 | for (i = 0; i < dir->nr_buffers; i++) |
182 | mark_buffer_dirty(bh: dir->bhs[i]); |
183 | } |
184 | |
185 | static int adfs_dir_sync(struct adfs_dir *dir) |
186 | { |
187 | int err = 0; |
188 | int i; |
189 | |
190 | for (i = dir->nr_buffers - 1; i >= 0; i--) { |
191 | struct buffer_head *bh = dir->bhs[i]; |
192 | sync_dirty_buffer(bh); |
193 | if (buffer_req(bh) && !buffer_uptodate(bh)) |
194 | err = -EIO; |
195 | } |
196 | |
197 | return err; |
198 | } |
199 | |
200 | void adfs_object_fixup(struct adfs_dir *dir, struct object_info *obj) |
201 | { |
202 | unsigned int dots, i; |
203 | |
204 | /* |
205 | * RISC OS allows the use of '/' in directory entry names, so we need |
206 | * to fix these up. '/' is typically used for FAT compatibility to |
207 | * represent '.', so do the same conversion here. In any case, '.' |
208 | * will never be in a RISC OS name since it is used as the pathname |
209 | * separator. Handle the case where we may generate a '.' or '..' |
210 | * name, replacing the first character with '^' (the RISC OS "parent |
211 | * directory" character.) |
212 | */ |
213 | for (i = dots = 0; i < obj->name_len; i++) |
214 | if (obj->name[i] == '/') { |
215 | obj->name[i] = '.'; |
216 | dots++; |
217 | } |
218 | |
219 | if (obj->name_len <= 2 && dots == obj->name_len) |
220 | obj->name[0] = '^'; |
221 | |
222 | /* |
223 | * If the object is a file, and the user requested the ,xyz hex |
224 | * filetype suffix to the name, check the filetype and append. |
225 | */ |
226 | if (!(obj->attr & ADFS_NDA_DIRECTORY) && ADFS_SB(sb: dir->sb)->s_ftsuffix) { |
227 | u16 filetype = adfs_filetype(loadaddr: obj->loadaddr); |
228 | |
229 | if (filetype != ADFS_FILETYPE_NONE) { |
230 | obj->name[obj->name_len++] = ','; |
231 | obj->name[obj->name_len++] = hex_asc_lo(filetype >> 8); |
232 | obj->name[obj->name_len++] = hex_asc_lo(filetype >> 4); |
233 | obj->name[obj->name_len++] = hex_asc_lo(filetype >> 0); |
234 | } |
235 | } |
236 | } |
237 | |
238 | static int adfs_iterate(struct file *file, struct dir_context *ctx) |
239 | { |
240 | struct inode *inode = file_inode(f: file); |
241 | struct super_block *sb = inode->i_sb; |
242 | const struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir; |
243 | struct adfs_dir dir; |
244 | int ret; |
245 | |
246 | down_read(sem: &adfs_dir_rwsem); |
247 | ret = adfs_dir_read_inode(sb, inode, dir: &dir); |
248 | if (ret) |
249 | goto unlock; |
250 | |
251 | if (ctx->pos == 0) { |
252 | if (!dir_emit_dot(file, ctx)) |
253 | goto unlock_relse; |
254 | ctx->pos = 1; |
255 | } |
256 | if (ctx->pos == 1) { |
257 | if (!dir_emit(ctx, name: ".." , namelen: 2, ino: dir.parent_id, DT_DIR)) |
258 | goto unlock_relse; |
259 | ctx->pos = 2; |
260 | } |
261 | |
262 | ret = ops->iterate(&dir, ctx); |
263 | |
264 | unlock_relse: |
265 | up_read(sem: &adfs_dir_rwsem); |
266 | adfs_dir_relse(dir: &dir); |
267 | return ret; |
268 | |
269 | unlock: |
270 | up_read(sem: &adfs_dir_rwsem); |
271 | return ret; |
272 | } |
273 | |
274 | int |
275 | adfs_dir_update(struct super_block *sb, struct object_info *obj, int wait) |
276 | { |
277 | const struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir; |
278 | struct adfs_dir dir; |
279 | int ret; |
280 | |
281 | if (!IS_ENABLED(CONFIG_ADFS_FS_RW)) |
282 | return -EINVAL; |
283 | |
284 | if (!ops->update) |
285 | return -EINVAL; |
286 | |
287 | down_write(sem: &adfs_dir_rwsem); |
288 | ret = adfs_dir_read(sb, indaddr: obj->parent_id, size: 0, dir: &dir); |
289 | if (ret) |
290 | goto unlock; |
291 | |
292 | ret = ops->update(&dir, obj); |
293 | if (ret) |
294 | goto forget; |
295 | |
296 | ret = ops->commit(&dir); |
297 | if (ret) |
298 | goto forget; |
299 | up_write(sem: &adfs_dir_rwsem); |
300 | |
301 | adfs_dir_mark_dirty(dir: &dir); |
302 | |
303 | if (wait) |
304 | ret = adfs_dir_sync(dir: &dir); |
305 | |
306 | adfs_dir_relse(dir: &dir); |
307 | return ret; |
308 | |
309 | /* |
310 | * If the updated failed because the entry wasn't found, we can |
311 | * just release the buffers. If it was any other error, forget |
312 | * the dirtied buffers so they aren't written back to the media. |
313 | */ |
314 | forget: |
315 | if (ret == -ENOENT) |
316 | adfs_dir_relse(dir: &dir); |
317 | else |
318 | adfs_dir_forget(dir: &dir); |
319 | unlock: |
320 | up_write(sem: &adfs_dir_rwsem); |
321 | |
322 | return ret; |
323 | } |
324 | |
325 | static unsigned char adfs_tolower(unsigned char c) |
326 | { |
327 | if (c >= 'A' && c <= 'Z') |
328 | c += 'a' - 'A'; |
329 | return c; |
330 | } |
331 | |
332 | static int __adfs_compare(const unsigned char *qstr, u32 qlen, |
333 | const char *str, u32 len) |
334 | { |
335 | u32 i; |
336 | |
337 | if (qlen != len) |
338 | return 1; |
339 | |
340 | for (i = 0; i < qlen; i++) |
341 | if (adfs_tolower(c: qstr[i]) != adfs_tolower(c: str[i])) |
342 | return 1; |
343 | |
344 | return 0; |
345 | } |
346 | |
347 | static int adfs_dir_lookup_byname(struct inode *inode, const struct qstr *qstr, |
348 | struct object_info *obj) |
349 | { |
350 | struct super_block *sb = inode->i_sb; |
351 | const struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir; |
352 | const unsigned char *name; |
353 | struct adfs_dir dir; |
354 | u32 name_len; |
355 | int ret; |
356 | |
357 | down_read(sem: &adfs_dir_rwsem); |
358 | ret = adfs_dir_read_inode(sb, inode, dir: &dir); |
359 | if (ret) |
360 | goto unlock; |
361 | |
362 | ret = ops->setpos(&dir, 0); |
363 | if (ret) |
364 | goto unlock_relse; |
365 | |
366 | ret = -ENOENT; |
367 | name = qstr->name; |
368 | name_len = qstr->len; |
369 | while (ops->getnext(&dir, obj) == 0) { |
370 | if (!__adfs_compare(qstr: name, qlen: name_len, str: obj->name, len: obj->name_len)) { |
371 | ret = 0; |
372 | break; |
373 | } |
374 | } |
375 | obj->parent_id = ADFS_I(inode)->indaddr; |
376 | |
377 | unlock_relse: |
378 | up_read(sem: &adfs_dir_rwsem); |
379 | adfs_dir_relse(dir: &dir); |
380 | return ret; |
381 | |
382 | unlock: |
383 | up_read(sem: &adfs_dir_rwsem); |
384 | return ret; |
385 | } |
386 | |
387 | const struct file_operations adfs_dir_operations = { |
388 | .read = generic_read_dir, |
389 | .llseek = generic_file_llseek, |
390 | .iterate_shared = adfs_iterate, |
391 | .fsync = generic_file_fsync, |
392 | }; |
393 | |
394 | static int |
395 | adfs_hash(const struct dentry *parent, struct qstr *qstr) |
396 | { |
397 | const unsigned char *name; |
398 | unsigned long hash; |
399 | u32 len; |
400 | |
401 | if (qstr->len > ADFS_SB(sb: parent->d_sb)->s_namelen) |
402 | return -ENAMETOOLONG; |
403 | |
404 | len = qstr->len; |
405 | name = qstr->name; |
406 | hash = init_name_hash(parent); |
407 | while (len--) |
408 | hash = partial_name_hash(c: adfs_tolower(c: *name++), prevhash: hash); |
409 | qstr->hash = end_name_hash(hash); |
410 | |
411 | return 0; |
412 | } |
413 | |
414 | /* |
415 | * Compare two names, taking note of the name length |
416 | * requirements of the underlying filesystem. |
417 | */ |
418 | static int adfs_compare(const struct dentry *dentry, unsigned int len, |
419 | const char *str, const struct qstr *qstr) |
420 | { |
421 | return __adfs_compare(qstr: qstr->name, qlen: qstr->len, str, len); |
422 | } |
423 | |
424 | const struct dentry_operations adfs_dentry_operations = { |
425 | .d_hash = adfs_hash, |
426 | .d_compare = adfs_compare, |
427 | }; |
428 | |
429 | static struct dentry * |
430 | adfs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
431 | { |
432 | struct inode *inode = NULL; |
433 | struct object_info obj; |
434 | int error; |
435 | |
436 | error = adfs_dir_lookup_byname(inode: dir, qstr: &dentry->d_name, obj: &obj); |
437 | if (error == 0) { |
438 | /* |
439 | * This only returns NULL if get_empty_inode |
440 | * fails. |
441 | */ |
442 | inode = adfs_iget(sb: dir->i_sb, obj: &obj); |
443 | if (!inode) |
444 | inode = ERR_PTR(error: -EACCES); |
445 | } else if (error != -ENOENT) { |
446 | inode = ERR_PTR(error); |
447 | } |
448 | return d_splice_alias(inode, dentry); |
449 | } |
450 | |
451 | /* |
452 | * directories can handle most operations... |
453 | */ |
454 | const struct inode_operations adfs_dir_inode_operations = { |
455 | .lookup = adfs_lookup, |
456 | .setattr = adfs_notify_change, |
457 | }; |
458 | |