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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/adfs/dir_f.c
4 *
5 * Copyright (C) 1997-1999 Russell King
6 *
7 * E and F format directory handling
8 */
9#include "adfs.h"
10#include "dir_f.h"
11
12/*
13 * Read an (unaligned) value of length 1..4 bytes
14 */
15static inline unsigned int adfs_readval(unsigned char *p, int len)
16{
17 unsigned int val = 0;
18
19 switch (len) {
20 case 4: val |= p[3] << 24;
21 fallthrough;
22 case 3: val |= p[2] << 16;
23 fallthrough;
24 case 2: val |= p[1] << 8;
25 fallthrough;
26 default: val |= p[0];
27 }
28 return val;
29}
30
31static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
32{
33 switch (len) {
34 case 4: p[3] = val >> 24;
35 fallthrough;
36 case 3: p[2] = val >> 16;
37 fallthrough;
38 case 2: p[1] = val >> 8;
39 fallthrough;
40 default: p[0] = val;
41 }
42}
43
44#define ror13(v) ((v >> 13) | (v << 19))
45
46#define dir_u8(idx) \
47 ({ int _buf = idx >> blocksize_bits; \
48 int _off = idx - (_buf << blocksize_bits);\
49 *(u8 *)(bh[_buf]->b_data + _off); \
50 })
51
52#define dir_u32(idx) \
53 ({ int _buf = idx >> blocksize_bits; \
54 int _off = idx - (_buf << blocksize_bits);\
55 *(__le32 *)(bh[_buf]->b_data + _off); \
56 })
57
58#define bufoff(_bh,_idx) \
59 ({ int _buf = _idx >> blocksize_bits; \
60 int _off = _idx - (_buf << blocksize_bits);\
61 (void *)(_bh[_buf]->b_data + _off); \
62 })
63
64/*
65 * There are some algorithms that are nice in
66 * assembler, but a bitch in C... This is one
67 * of them.
68 */
69static u8
70adfs_dir_checkbyte(const struct adfs_dir *dir)
71{
72 struct buffer_head * const *bh = dir->bh;
73 const int blocksize_bits = dir->sb->s_blocksize_bits;
74 union { __le32 *ptr32; u8 *ptr8; } ptr, end;
75 u32 dircheck = 0;
76 int last = 5 - 26;
77 int i = 0;
78
79 /*
80 * Accumulate each word up to the last whole
81 * word of the last directory entry. This
82 * can spread across several buffer heads.
83 */
84 do {
85 last += 26;
86 do {
87 dircheck = le32_to_cpu(dir_u32(i)) ^ ror13(dircheck);
88
89 i += sizeof(u32);
90 } while (i < (last & ~3));
91 } while (dir_u8(last) != 0);
92
93 /*
94 * Accumulate the last few bytes. These
95 * bytes will be within the same bh.
96 */
97 if (i != last) {
98 ptr.ptr8 = bufoff(bh, i);
99 end.ptr8 = ptr.ptr8 + last - i;
100
101 do {
102 dircheck = *ptr.ptr8++ ^ ror13(dircheck);
103 } while (ptr.ptr8 < end.ptr8);
104 }
105
106 /*
107 * The directory tail is in the final bh
108 * Note that contary to the RISC OS PRMs,
109 * the first few bytes are NOT included
110 * in the check. All bytes are in the
111 * same bh.
112 */
113 ptr.ptr8 = bufoff(bh, 2008);
114 end.ptr8 = ptr.ptr8 + 36;
115
116 do {
117 __le32 v = *ptr.ptr32++;
118 dircheck = le32_to_cpu(v) ^ ror13(dircheck);
119 } while (ptr.ptr32 < end.ptr32);
120
121 return (dircheck ^ (dircheck >> 8) ^ (dircheck >> 16) ^ (dircheck >> 24)) & 0xff;
122}
123
124static int adfs_f_validate(struct adfs_dir *dir)
125{
126 struct adfs_dirheader *head = dir->dirhead;
127 struct adfs_newdirtail *tail = dir->newtail;
128
129 if (head->startmasseq != tail->endmasseq ||
130 tail->dirlastmask || tail->reserved[0] || tail->reserved[1] ||
131 (memcmp(&head->startname, "Nick", 4) &&
132 memcmp(&head->startname, "Hugo", 4)) ||
133 memcmp(&head->startname, &tail->endname, 4) ||
134 adfs_dir_checkbyte(dir) != tail->dircheckbyte)
135 return -EIO;
136
137 return 0;
138}
139
140/* Read and check that a directory is valid */
141static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
142 struct adfs_dir *dir)
143{
144 const unsigned int blocksize_bits = sb->s_blocksize_bits;
145 int ret;
146
147 if (size && size != ADFS_NEWDIR_SIZE)
148 return -EIO;
149
150 ret = adfs_dir_read_buffers(sb, indaddr, ADFS_NEWDIR_SIZE, dir);
151 if (ret)
152 return ret;
153
154 dir->dirhead = bufoff(dir->bh, 0);
155 dir->newtail = bufoff(dir->bh, 2007);
156
157 if (adfs_f_validate(dir))
158 goto bad_dir;
159
160 dir->parent_id = adfs_readval(dir->newtail->dirparent, 3);
161
162 return 0;
163
164bad_dir:
165 adfs_error(sb, "dir %06x is corrupted", indaddr);
166 adfs_dir_relse(dir);
167
168 return -EIO;
169}
170
171/*
172 * convert a disk-based directory entry to a Linux ADFS directory entry
173 */
174static inline void
175adfs_dir2obj(struct adfs_dir *dir, struct object_info *obj,
176 struct adfs_direntry *de)
177{
178 unsigned int name_len;
179
180 for (name_len = 0; name_len < ADFS_F_NAME_LEN; name_len++) {
181 if (de->dirobname[name_len] < ' ')
182 break;
183
184 obj->name[name_len] = de->dirobname[name_len];
185 }
186
187 obj->name_len = name_len;
188 obj->indaddr = adfs_readval(de->dirinddiscadd, 3);
189 obj->loadaddr = adfs_readval(de->dirload, 4);
190 obj->execaddr = adfs_readval(de->direxec, 4);
191 obj->size = adfs_readval(de->dirlen, 4);
192 obj->attr = de->newdiratts;
193
194 adfs_object_fixup(dir, obj);
195}
196
197/*
198 * convert a Linux ADFS directory entry to a disk-based directory entry
199 */
200static inline void
201adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj)
202{
203 adfs_writeval(de->dirinddiscadd, 3, obj->indaddr);
204 adfs_writeval(de->dirload, 4, obj->loadaddr);
205 adfs_writeval(de->direxec, 4, obj->execaddr);
206 adfs_writeval(de->dirlen, 4, obj->size);
207 de->newdiratts = obj->attr;
208}
209
210/*
211 * get a directory entry. Note that the caller is responsible
212 * for holding the relevant locks.
213 */
214static int
215__adfs_dir_get(struct adfs_dir *dir, int pos, struct object_info *obj)
216{
217 struct adfs_direntry de;
218 int ret;
219
220 ret = adfs_dir_copyfrom(&de, dir, pos, 26);
221 if (ret)
222 return ret;
223
224 if (!de.dirobname[0])
225 return -ENOENT;
226
227 adfs_dir2obj(dir, obj, &de);
228
229 return 0;
230}
231
232static int
233adfs_f_setpos(struct adfs_dir *dir, unsigned int fpos)
234{
235 if (fpos >= ADFS_NUM_DIR_ENTRIES)
236 return -ENOENT;
237
238 dir->pos = 5 + fpos * 26;
239 return 0;
240}
241
242static int
243adfs_f_getnext(struct adfs_dir *dir, struct object_info *obj)
244{
245 unsigned int ret;
246
247 ret = __adfs_dir_get(dir, dir->pos, obj);
248 if (ret == 0)
249 dir->pos += 26;
250
251 return ret;
252}
253
254static int adfs_f_iterate(struct adfs_dir *dir, struct dir_context *ctx)
255{
256 struct object_info obj;
257 int pos = 5 + (ctx->pos - 2) * 26;
258
259 while (ctx->pos < 2 + ADFS_NUM_DIR_ENTRIES) {
260 if (__adfs_dir_get(dir, pos, &obj))
261 break;
262 if (!dir_emit(ctx, obj.name, obj.name_len,
263 obj.indaddr, DT_UNKNOWN))
264 break;
265 pos += 26;
266 ctx->pos++;
267 }
268 return 0;
269}
270
271static int adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
272{
273 struct adfs_direntry de;
274 int offset, ret;
275
276 offset = 5 - (int)sizeof(de);
277
278 do {
279 offset += sizeof(de);
280 ret = adfs_dir_copyfrom(&de, dir, offset, sizeof(de));
281 if (ret) {
282 adfs_error(dir->sb, "error reading directory entry");
283 return -ENOENT;
284 }
285 if (!de.dirobname[0]) {
286 adfs_error(dir->sb, "unable to locate entry to update");
287 return -ENOENT;
288 }
289 } while (adfs_readval(de.dirinddiscadd, 3) != obj->indaddr);
290
291 /* Update the directory entry with the new object state */
292 adfs_obj2dir(&de, obj);
293
294 /* Write the directory entry back to the directory */
295 return adfs_dir_copyto(dir, offset, &de, 26);
296}
297
298static int adfs_f_commit(struct adfs_dir *dir)
299{
300 int ret;
301
302 /* Increment directory sequence number */
303 dir->dirhead->startmasseq += 1;
304 dir->newtail->endmasseq += 1;
305
306 /* Update directory check byte */
307 dir->newtail->dircheckbyte = adfs_dir_checkbyte(dir);
308
309 /* Make sure the directory still validates correctly */
310 ret = adfs_f_validate(dir);
311 if (ret)
312 adfs_msg(dir->sb, KERN_ERR, "error: update broke directory");
313
314 return ret;
315}
316
317const struct adfs_dir_ops adfs_f_dir_ops = {
318 .read = adfs_f_read,
319 .iterate = adfs_f_iterate,
320 .setpos = adfs_f_setpos,
321 .getnext = adfs_f_getnext,
322 .update = adfs_f_update,
323 .commit = adfs_f_commit,
324};
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/adfs/dir_f.c
4 *
5 * Copyright (C) 1997-1999 Russell King
6 *
7 * E and F format directory handling
8 */
9#include "adfs.h"
10#include "dir_f.h"
11
12static void adfs_f_free(struct adfs_dir *dir);
13
14/*
15 * Read an (unaligned) value of length 1..4 bytes
16 */
17static 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;
23 /* fall through */
24 case 3: val |= p[2] << 16;
25 /* fall through */
26 case 2: val |= p[1] << 8;
27 /* fall through */
28 default: val |= p[0];
29 }
30 return val;
31}
32
33static inline void adfs_writeval(unsigned char *p, int len, unsigned int val)
34{
35 switch (len) {
36 case 4: p[3] = val >> 24;
37 /* fall through */
38 case 3: p[2] = val >> 16;
39 /* fall through */
40 case 2: p[1] = val >> 8;
41 /* fall through */
42 default: p[0] = val;
43 }
44}
45
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 */
71static u8
72adfs_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
103 do {
104 dircheck = *ptr.ptr8++ ^ ror13(dircheck);
105 } while (ptr.ptr8 < end.ptr8);
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
126/* Read and check that a directory is valid */
127static int adfs_dir_read(struct super_block *sb, u32 indaddr,
128 unsigned int size, struct adfs_dir *dir)
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
148 phys = __adfs_block_map(sb, indaddr, blk);
149 if (!phys) {
150 adfs_error(sb, "dir %06x has a hole at offset %d",
151 indaddr, blk);
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
178bad_dir:
179 adfs_error(sb, "dir %06x is corrupted", indaddr);
180release_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 */
192static inline void
193adfs_dir2obj(struct adfs_dir *dir, struct object_info *obj,
194 struct adfs_direntry *de)
195{
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;
206 obj->indaddr = adfs_readval(de->dirinddiscadd, 3);
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;
211
212 adfs_object_fixup(dir, obj);
213}
214
215/*
216 * convert a Linux ADFS directory entry to a disk-based directory entry
217 */
218static inline void
219adfs_obj2dir(struct adfs_direntry *de, struct object_info *obj)
220{
221 adfs_writeval(de->dirinddiscadd, 3, obj->indaddr);
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 */
232static 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
257 adfs_dir2obj(dir, obj, &de);
258
259 return 0;
260}
261
262static 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 */
307static int adfs_dir_find_entry(struct adfs_dir *dir, u32 indaddr)
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
319 if (obj.indaddr == indaddr) {
320 ret = pos;
321 break;
322 }
323 }
324
325 return ret;
326}
327
328static int adfs_f_read(struct super_block *sb, u32 indaddr, unsigned int size,
329 struct adfs_dir *dir)
330{
331 int ret;
332
333 if (size != ADFS_NEWDIR_SIZE)
334 return -EIO;
335
336 ret = adfs_dir_read(sb, indaddr, size, dir);
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
345static int
346adfs_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
355static int
356adfs_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
367static int
368adfs_f_update(struct adfs_dir *dir, struct object_info *obj)
369{
370 struct super_block *sb = dir->sb;
371 int ret, i;
372
373 ret = adfs_dir_find_entry(dir, obj->indaddr);
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;
416out:
417 return ret;
418#if 1
419bad_dir:
420 adfs_error(dir->sb, "whoops! I broke a directory!");
421 return -EIO;
422#endif
423}
424
425static int
426adfs_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
441static void
442adfs_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
455const struct adfs_dir_ops adfs_f_dir_ops = {
456 .read = adfs_f_read,
457 .setpos = adfs_f_setpos,
458 .getnext = adfs_f_getnext,
459 .update = adfs_f_update,
460 .sync = adfs_f_sync,
461 .free = adfs_f_free
462};