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 */
15static DECLARE_RWSEM(adfs_dir_rwsem);
16
17int 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
42int 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
67static 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
77void 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
87static 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
97int 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
140error:
141 adfs_dir_relse(dir);
142
143 return -EIO;
144}
145
146static 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
156static 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
176static 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
185static 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
200void 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
238static 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
264unlock_relse:
265 up_read(sem: &adfs_dir_rwsem);
266 adfs_dir_relse(dir: &dir);
267 return ret;
268
269unlock:
270 up_read(sem: &adfs_dir_rwsem);
271 return ret;
272}
273
274int
275adfs_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 */
314forget:
315 if (ret == -ENOENT)
316 adfs_dir_relse(dir: &dir);
317 else
318 adfs_dir_forget(dir: &dir);
319unlock:
320 up_write(sem: &adfs_dir_rwsem);
321
322 return ret;
323}
324
325static unsigned char adfs_tolower(unsigned char c)
326{
327 if (c >= 'A' && c <= 'Z')
328 c += 'a' - 'A';
329 return c;
330}
331
332static 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
347static 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
377unlock_relse:
378 up_read(sem: &adfs_dir_rwsem);
379 adfs_dir_relse(dir: &dir);
380 return ret;
381
382unlock:
383 up_read(sem: &adfs_dir_rwsem);
384 return ret;
385}
386
387const 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
394static int
395adfs_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 */
418static 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
424const struct dentry_operations adfs_dentry_operations = {
425 .d_hash = adfs_hash,
426 .d_compare = adfs_compare,
427};
428
429static struct dentry *
430adfs_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 */
454const struct inode_operations adfs_dir_inode_operations = {
455 .lookup = adfs_lookup,
456 .setattr = adfs_notify_change,
457};
458

source code of linux/fs/adfs/dir.c