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