1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/fs/adfs/super.c
4 *
5 * Copyright (C) 1997-1999 Russell King
6 */
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/parser.h>
10 #include <linux/mount.h>
11 #include <linux/seq_file.h>
12 #include <linux/slab.h>
13 #include <linux/statfs.h>
14 #include <linux/user_namespace.h>
15 #include "adfs.h"
16 #include "dir_f.h"
17 #include "dir_fplus.h"
18
19 #define ADFS_SB_FLAGS SB_NOATIME
20
21 #define ADFS_DEFAULT_OWNER_MASK S_IRWXU
22 #define ADFS_DEFAULT_OTHER_MASK (S_IRWXG | S_IRWXO)
23
__adfs_error(struct super_block * sb,const char * function,const char * fmt,...)24 void __adfs_error(struct super_block *sb, const char *function, const char *fmt, ...)
25 {
26 struct va_format vaf;
27 va_list args;
28
29 va_start(args, fmt);
30 vaf.fmt = fmt;
31 vaf.va = &args;
32
33 printk(KERN_CRIT "ADFS-fs error (device %s)%s%s: %pV\n",
34 sb->s_id, function ? ": " : "",
35 function ? function : "", &vaf);
36
37 va_end(args);
38 }
39
adfs_msg(struct super_block * sb,const char * pfx,const char * fmt,...)40 void adfs_msg(struct super_block *sb, const char *pfx, const char *fmt, ...)
41 {
42 struct va_format vaf;
43 va_list args;
44
45 va_start(args, fmt);
46 vaf.fmt = fmt;
47 vaf.va = &args;
48 printk("%sADFS-fs (%s): %pV\n", pfx, sb->s_id, &vaf);
49 va_end(args);
50 }
51
adfs_checkdiscrecord(struct adfs_discrecord * dr)52 static int adfs_checkdiscrecord(struct adfs_discrecord *dr)
53 {
54 unsigned int max_idlen;
55 int i;
56
57 /* sector size must be 256, 512 or 1024 bytes */
58 if (dr->log2secsize != 8 &&
59 dr->log2secsize != 9 &&
60 dr->log2secsize != 10)
61 return 1;
62
63 /* idlen must be at least log2secsize + 3 */
64 if (dr->idlen < dr->log2secsize + 3)
65 return 1;
66
67 /* we cannot have such a large disc that we
68 * are unable to represent sector offsets in
69 * 32 bits. This works out at 2.0 TB.
70 */
71 if (le32_to_cpu(dr->disc_size_high) >> dr->log2secsize)
72 return 1;
73
74 /*
75 * Maximum idlen is limited to 16 bits for new directories by
76 * the three-byte storage of an indirect disc address. For
77 * big directories, idlen must be no greater than 19 v2 [1.0]
78 */
79 max_idlen = dr->format_version ? 19 : 16;
80 if (dr->idlen > max_idlen)
81 return 1;
82
83 /* reserved bytes should be zero */
84 for (i = 0; i < sizeof(dr->unused52); i++)
85 if (dr->unused52[i] != 0)
86 return 1;
87
88 return 0;
89 }
90
adfs_calczonecheck(struct super_block * sb,unsigned char * map)91 static unsigned char adfs_calczonecheck(struct super_block *sb, unsigned char *map)
92 {
93 unsigned int v0, v1, v2, v3;
94 int i;
95
96 v0 = v1 = v2 = v3 = 0;
97 for (i = sb->s_blocksize - 4; i; i -= 4) {
98 v0 += map[i] + (v3 >> 8);
99 v3 &= 0xff;
100 v1 += map[i + 1] + (v0 >> 8);
101 v0 &= 0xff;
102 v2 += map[i + 2] + (v1 >> 8);
103 v1 &= 0xff;
104 v3 += map[i + 3] + (v2 >> 8);
105 v2 &= 0xff;
106 }
107 v0 += v3 >> 8;
108 v1 += map[1] + (v0 >> 8);
109 v2 += map[2] + (v1 >> 8);
110 v3 += map[3] + (v2 >> 8);
111
112 return v0 ^ v1 ^ v2 ^ v3;
113 }
114
adfs_checkmap(struct super_block * sb,struct adfs_discmap * dm)115 static int adfs_checkmap(struct super_block *sb, struct adfs_discmap *dm)
116 {
117 unsigned char crosscheck = 0, zonecheck = 1;
118 int i;
119
120 for (i = 0; i < ADFS_SB(sb)->s_map_size; i++) {
121 unsigned char *map;
122
123 map = dm[i].dm_bh->b_data;
124
125 if (adfs_calczonecheck(sb, map) != map[0]) {
126 adfs_error(sb, "zone %d fails zonecheck", i);
127 zonecheck = 0;
128 }
129 crosscheck ^= map[3];
130 }
131 if (crosscheck != 0xff)
132 adfs_error(sb, "crosscheck != 0xff");
133 return crosscheck == 0xff && zonecheck;
134 }
135
adfs_put_super(struct super_block * sb)136 static void adfs_put_super(struct super_block *sb)
137 {
138 int i;
139 struct adfs_sb_info *asb = ADFS_SB(sb);
140
141 for (i = 0; i < asb->s_map_size; i++)
142 brelse(asb->s_map[i].dm_bh);
143 kfree(asb->s_map);
144 kfree_rcu(asb, rcu);
145 }
146
adfs_show_options(struct seq_file * seq,struct dentry * root)147 static int adfs_show_options(struct seq_file *seq, struct dentry *root)
148 {
149 struct adfs_sb_info *asb = ADFS_SB(root->d_sb);
150
151 if (!uid_eq(asb->s_uid, GLOBAL_ROOT_UID))
152 seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, asb->s_uid));
153 if (!gid_eq(asb->s_gid, GLOBAL_ROOT_GID))
154 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, asb->s_gid));
155 if (asb->s_owner_mask != ADFS_DEFAULT_OWNER_MASK)
156 seq_printf(seq, ",ownmask=%o", asb->s_owner_mask);
157 if (asb->s_other_mask != ADFS_DEFAULT_OTHER_MASK)
158 seq_printf(seq, ",othmask=%o", asb->s_other_mask);
159 if (asb->s_ftsuffix != 0)
160 seq_printf(seq, ",ftsuffix=%u", asb->s_ftsuffix);
161
162 return 0;
163 }
164
165 enum {Opt_uid, Opt_gid, Opt_ownmask, Opt_othmask, Opt_ftsuffix, Opt_err};
166
167 static const match_table_t tokens = {
168 {Opt_uid, "uid=%u"},
169 {Opt_gid, "gid=%u"},
170 {Opt_ownmask, "ownmask=%o"},
171 {Opt_othmask, "othmask=%o"},
172 {Opt_ftsuffix, "ftsuffix=%u"},
173 {Opt_err, NULL}
174 };
175
parse_options(struct super_block * sb,struct adfs_sb_info * asb,char * options)176 static int parse_options(struct super_block *sb, struct adfs_sb_info *asb,
177 char *options)
178 {
179 char *p;
180 int option;
181
182 if (!options)
183 return 0;
184
185 while ((p = strsep(&options, ",")) != NULL) {
186 substring_t args[MAX_OPT_ARGS];
187 int token;
188 if (!*p)
189 continue;
190
191 token = match_token(p, tokens, args);
192 switch (token) {
193 case Opt_uid:
194 if (match_int(args, &option))
195 return -EINVAL;
196 asb->s_uid = make_kuid(current_user_ns(), option);
197 if (!uid_valid(asb->s_uid))
198 return -EINVAL;
199 break;
200 case Opt_gid:
201 if (match_int(args, &option))
202 return -EINVAL;
203 asb->s_gid = make_kgid(current_user_ns(), option);
204 if (!gid_valid(asb->s_gid))
205 return -EINVAL;
206 break;
207 case Opt_ownmask:
208 if (match_octal(args, &option))
209 return -EINVAL;
210 asb->s_owner_mask = option;
211 break;
212 case Opt_othmask:
213 if (match_octal(args, &option))
214 return -EINVAL;
215 asb->s_other_mask = option;
216 break;
217 case Opt_ftsuffix:
218 if (match_int(args, &option))
219 return -EINVAL;
220 asb->s_ftsuffix = option;
221 break;
222 default:
223 adfs_msg(sb, KERN_ERR,
224 "unrecognised mount option \"%s\" or missing value",
225 p);
226 return -EINVAL;
227 }
228 }
229 return 0;
230 }
231
adfs_remount(struct super_block * sb,int * flags,char * data)232 static int adfs_remount(struct super_block *sb, int *flags, char *data)
233 {
234 struct adfs_sb_info temp_asb;
235 int ret;
236
237 sync_filesystem(sb);
238 *flags |= ADFS_SB_FLAGS;
239
240 temp_asb = *ADFS_SB(sb);
241 ret = parse_options(sb, &temp_asb, data);
242 if (ret == 0)
243 *ADFS_SB(sb) = temp_asb;
244
245 return ret;
246 }
247
adfs_statfs(struct dentry * dentry,struct kstatfs * buf)248 static int adfs_statfs(struct dentry *dentry, struct kstatfs *buf)
249 {
250 struct super_block *sb = dentry->d_sb;
251 struct adfs_sb_info *sbi = ADFS_SB(sb);
252 struct adfs_discrecord *dr = adfs_map_discrecord(sbi->s_map);
253 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
254
255 buf->f_type = ADFS_SUPER_MAGIC;
256 buf->f_namelen = sbi->s_namelen;
257 buf->f_bsize = sb->s_blocksize;
258 buf->f_blocks = adfs_disc_size(dr) >> sb->s_blocksize_bits;
259 buf->f_files = sbi->s_ids_per_zone * sbi->s_map_size;
260 buf->f_bavail =
261 buf->f_bfree = adfs_map_free(sb);
262 buf->f_ffree = (long)(buf->f_bfree * buf->f_files) / (long)buf->f_blocks;
263 buf->f_fsid.val[0] = (u32)id;
264 buf->f_fsid.val[1] = (u32)(id >> 32);
265
266 return 0;
267 }
268
269 static struct kmem_cache *adfs_inode_cachep;
270
adfs_alloc_inode(struct super_block * sb)271 static struct inode *adfs_alloc_inode(struct super_block *sb)
272 {
273 struct adfs_inode_info *ei;
274 ei = kmem_cache_alloc(adfs_inode_cachep, GFP_KERNEL);
275 if (!ei)
276 return NULL;
277 return &ei->vfs_inode;
278 }
279
adfs_free_inode(struct inode * inode)280 static void adfs_free_inode(struct inode *inode)
281 {
282 kmem_cache_free(adfs_inode_cachep, ADFS_I(inode));
283 }
284
init_once(void * foo)285 static void init_once(void *foo)
286 {
287 struct adfs_inode_info *ei = (struct adfs_inode_info *) foo;
288
289 inode_init_once(&ei->vfs_inode);
290 }
291
init_inodecache(void)292 static int __init init_inodecache(void)
293 {
294 adfs_inode_cachep = kmem_cache_create("adfs_inode_cache",
295 sizeof(struct adfs_inode_info),
296 0, (SLAB_RECLAIM_ACCOUNT|
297 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
298 init_once);
299 if (adfs_inode_cachep == NULL)
300 return -ENOMEM;
301 return 0;
302 }
303
destroy_inodecache(void)304 static void destroy_inodecache(void)
305 {
306 /*
307 * Make sure all delayed rcu free inodes are flushed before we
308 * destroy cache.
309 */
310 rcu_barrier();
311 kmem_cache_destroy(adfs_inode_cachep);
312 }
313
314 static const struct super_operations adfs_sops = {
315 .alloc_inode = adfs_alloc_inode,
316 .free_inode = adfs_free_inode,
317 .drop_inode = generic_delete_inode,
318 .write_inode = adfs_write_inode,
319 .put_super = adfs_put_super,
320 .statfs = adfs_statfs,
321 .remount_fs = adfs_remount,
322 .show_options = adfs_show_options,
323 };
324
adfs_read_map(struct super_block * sb,struct adfs_discrecord * dr)325 static struct adfs_discmap *adfs_read_map(struct super_block *sb, struct adfs_discrecord *dr)
326 {
327 struct adfs_discmap *dm;
328 unsigned int map_addr, zone_size, nzones;
329 int i, zone;
330 struct adfs_sb_info *asb = ADFS_SB(sb);
331
332 nzones = asb->s_map_size;
333 zone_size = (8 << dr->log2secsize) - le16_to_cpu(dr->zone_spare);
334 map_addr = (nzones >> 1) * zone_size -
335 ((nzones > 1) ? ADFS_DR_SIZE_BITS : 0);
336 map_addr = signed_asl(map_addr, asb->s_map2blk);
337
338 asb->s_ids_per_zone = zone_size / (asb->s_idlen + 1);
339
340 dm = kmalloc_array(nzones, sizeof(*dm), GFP_KERNEL);
341 if (dm == NULL) {
342 adfs_error(sb, "not enough memory");
343 return ERR_PTR(-ENOMEM);
344 }
345
346 for (zone = 0; zone < nzones; zone++, map_addr++) {
347 dm[zone].dm_startbit = 0;
348 dm[zone].dm_endbit = zone_size;
349 dm[zone].dm_startblk = zone * zone_size - ADFS_DR_SIZE_BITS;
350 dm[zone].dm_bh = sb_bread(sb, map_addr);
351
352 if (!dm[zone].dm_bh) {
353 adfs_error(sb, "unable to read map");
354 goto error_free;
355 }
356 }
357
358 /* adjust the limits for the first and last map zones */
359 i = zone - 1;
360 dm[0].dm_startblk = 0;
361 dm[0].dm_startbit = ADFS_DR_SIZE_BITS;
362 dm[i].dm_endbit = (adfs_disc_size(dr) >> dr->log2bpmb) +
363 (ADFS_DR_SIZE_BITS - i * zone_size);
364
365 if (adfs_checkmap(sb, dm))
366 return dm;
367
368 adfs_error(sb, "map corrupted");
369
370 error_free:
371 while (--zone >= 0)
372 brelse(dm[zone].dm_bh);
373
374 kfree(dm);
375 return ERR_PTR(-EIO);
376 }
377
adfs_fill_super(struct super_block * sb,void * data,int silent)378 static int adfs_fill_super(struct super_block *sb, void *data, int silent)
379 {
380 struct adfs_discrecord *dr;
381 struct buffer_head *bh;
382 struct object_info root_obj;
383 unsigned char *b_data;
384 unsigned int blocksize;
385 struct adfs_sb_info *asb;
386 struct inode *root;
387 int ret = -EINVAL;
388
389 sb->s_flags |= ADFS_SB_FLAGS;
390
391 asb = kzalloc(sizeof(*asb), GFP_KERNEL);
392 if (!asb)
393 return -ENOMEM;
394 sb->s_fs_info = asb;
395
396 /* set default options */
397 asb->s_uid = GLOBAL_ROOT_UID;
398 asb->s_gid = GLOBAL_ROOT_GID;
399 asb->s_owner_mask = ADFS_DEFAULT_OWNER_MASK;
400 asb->s_other_mask = ADFS_DEFAULT_OTHER_MASK;
401 asb->s_ftsuffix = 0;
402
403 if (parse_options(sb, asb, data))
404 goto error;
405
406 sb_set_blocksize(sb, BLOCK_SIZE);
407 if (!(bh = sb_bread(sb, ADFS_DISCRECORD / BLOCK_SIZE))) {
408 adfs_msg(sb, KERN_ERR, "error: unable to read superblock");
409 ret = -EIO;
410 goto error;
411 }
412
413 b_data = bh->b_data + (ADFS_DISCRECORD % BLOCK_SIZE);
414
415 if (adfs_checkbblk(b_data)) {
416 ret = -EINVAL;
417 goto error_badfs;
418 }
419
420 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
421
422 /*
423 * Do some sanity checks on the ADFS disc record
424 */
425 if (adfs_checkdiscrecord(dr)) {
426 ret = -EINVAL;
427 goto error_badfs;
428 }
429
430 blocksize = 1 << dr->log2secsize;
431 brelse(bh);
432
433 if (sb_set_blocksize(sb, blocksize)) {
434 bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
435 if (!bh) {
436 adfs_msg(sb, KERN_ERR,
437 "error: couldn't read superblock on 2nd try.");
438 ret = -EIO;
439 goto error;
440 }
441 b_data = bh->b_data + (ADFS_DISCRECORD % sb->s_blocksize);
442 if (adfs_checkbblk(b_data)) {
443 adfs_msg(sb, KERN_ERR,
444 "error: disc record mismatch, very weird!");
445 ret = -EINVAL;
446 goto error_free_bh;
447 }
448 dr = (struct adfs_discrecord *)(b_data + ADFS_DR_OFFSET);
449 } else {
450 if (!silent)
451 adfs_msg(sb, KERN_ERR,
452 "error: unsupported blocksize");
453 ret = -EINVAL;
454 goto error;
455 }
456
457 /*
458 * blocksize on this device should now be set to the ADFS log2secsize
459 */
460
461 sb->s_magic = ADFS_SUPER_MAGIC;
462 asb->s_idlen = dr->idlen;
463 asb->s_map_size = dr->nzones | (dr->nzones_high << 8);
464 asb->s_map2blk = dr->log2bpmb - dr->log2secsize;
465 asb->s_log2sharesize = dr->log2sharesize;
466
467 asb->s_map = adfs_read_map(sb, dr);
468 if (IS_ERR(asb->s_map)) {
469 ret = PTR_ERR(asb->s_map);
470 goto error_free_bh;
471 }
472
473 brelse(bh);
474
475 /*
476 * set up enough so that we can read an inode
477 */
478 sb->s_op = &adfs_sops;
479
480 dr = adfs_map_discrecord(asb->s_map);
481
482 root_obj.parent_id = root_obj.indaddr = le32_to_cpu(dr->root);
483 root_obj.name_len = 0;
484 /* Set root object date as 01 Jan 1987 00:00:00 */
485 root_obj.loadaddr = 0xfff0003f;
486 root_obj.execaddr = 0xec22c000;
487 root_obj.size = ADFS_NEWDIR_SIZE;
488 root_obj.attr = ADFS_NDA_DIRECTORY | ADFS_NDA_OWNER_READ |
489 ADFS_NDA_OWNER_WRITE | ADFS_NDA_PUBLIC_READ;
490
491 /*
492 * If this is a F+ disk with variable length directories,
493 * get the root_size from the disc record.
494 */
495 if (dr->format_version) {
496 root_obj.size = le32_to_cpu(dr->root_size);
497 asb->s_dir = &adfs_fplus_dir_ops;
498 asb->s_namelen = ADFS_FPLUS_NAME_LEN;
499 } else {
500 asb->s_dir = &adfs_f_dir_ops;
501 asb->s_namelen = ADFS_F_NAME_LEN;
502 }
503 /*
504 * ,xyz hex filetype suffix may be added by driver
505 * to files that have valid RISC OS filetype
506 */
507 if (asb->s_ftsuffix)
508 asb->s_namelen += 4;
509
510 sb->s_d_op = &adfs_dentry_operations;
511 root = adfs_iget(sb, &root_obj);
512 sb->s_root = d_make_root(root);
513 if (!sb->s_root) {
514 int i;
515 for (i = 0; i < asb->s_map_size; i++)
516 brelse(asb->s_map[i].dm_bh);
517 kfree(asb->s_map);
518 adfs_error(sb, "get root inode failed\n");
519 ret = -EIO;
520 goto error;
521 }
522 return 0;
523
524 error_badfs:
525 if (!silent)
526 adfs_msg(sb, KERN_ERR,
527 "error: can't find an ADFS filesystem on dev %s.",
528 sb->s_id);
529 error_free_bh:
530 brelse(bh);
531 error:
532 sb->s_fs_info = NULL;
533 kfree(asb);
534 return ret;
535 }
536
adfs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * data)537 static struct dentry *adfs_mount(struct file_system_type *fs_type,
538 int flags, const char *dev_name, void *data)
539 {
540 return mount_bdev(fs_type, flags, dev_name, data, adfs_fill_super);
541 }
542
543 static struct file_system_type adfs_fs_type = {
544 .owner = THIS_MODULE,
545 .name = "adfs",
546 .mount = adfs_mount,
547 .kill_sb = kill_block_super,
548 .fs_flags = FS_REQUIRES_DEV,
549 };
550 MODULE_ALIAS_FS("adfs");
551
init_adfs_fs(void)552 static int __init init_adfs_fs(void)
553 {
554 int err = init_inodecache();
555 if (err)
556 goto out1;
557 err = register_filesystem(&adfs_fs_type);
558 if (err)
559 goto out;
560 return 0;
561 out:
562 destroy_inodecache();
563 out1:
564 return err;
565 }
566
exit_adfs_fs(void)567 static void __exit exit_adfs_fs(void)
568 {
569 unregister_filesystem(&adfs_fs_type);
570 destroy_inodecache();
571 }
572
573 module_init(init_adfs_fs)
574 module_exit(exit_adfs_fs)
575 MODULE_LICENSE("GPL");
576