aboutsummaryrefslogtreecommitdiff
path: root/fs/vboxsf/utils.c
blob: e1db0f3f7e5e4ce9b79fa2ba86cf3a08824d7ce1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
// SPDX-License-Identifier: MIT
/*
 * VirtualBox Guest Shared Folders support: Utility functions.
 * Mainly conversion from/to VirtualBox/Linux data structures.
 *
 * Copyright (C) 2006-2018 Oracle Corporation
 */

#include <linux/namei.h>
#include <linux/nls.h>
#include <linux/sizes.h>
#include <linux/pagemap.h>
#include <linux/vfs.h>
#include "vfsmod.h"

struct inode *vboxsf_new_inode(struct super_block *sb)
{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(sb);
	struct inode *inode;
	unsigned long flags;
	int cursor, ret;
	u32 gen;

	inode = new_inode(sb);
	if (!inode)
		return ERR_PTR(-ENOMEM);

	idr_preload(GFP_KERNEL);
	spin_lock_irqsave(&sbi->ino_idr_lock, flags);
	cursor = idr_get_cursor(&sbi->ino_idr);
	ret = idr_alloc_cyclic(&sbi->ino_idr, inode, 1, 0, GFP_ATOMIC);
	if (ret >= 0 && ret < cursor)
		sbi->next_generation++;
	gen = sbi->next_generation;
	spin_unlock_irqrestore(&sbi->ino_idr_lock, flags);
	idr_preload_end();

	if (ret < 0) {
		iput(inode);
		return ERR_PTR(ret);
	}

	inode->i_ino = ret;
	inode->i_generation = gen;
	return inode;
}

/* set [inode] attributes based on [info], uid/gid based on [sbi] */
int vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
		       const struct shfl_fsobjinfo *info, bool reinit)
{
	const struct shfl_fsobjattr *attr;
	s64 allocated;
	umode_t mode;

	attr = &info->attr;

#define mode_set(r) ((attr->mode & (SHFL_UNIX_##r)) ? (S_##r) : 0)

	mode = mode_set(IRUSR);
	mode |= mode_set(IWUSR);
	mode |= mode_set(IXUSR);

	mode |= mode_set(IRGRP);
	mode |= mode_set(IWGRP);
	mode |= mode_set(IXGRP);

	mode |= mode_set(IROTH);
	mode |= mode_set(IWOTH);
	mode |= mode_set(IXOTH);

#undef mode_set

	/* We use the host-side values for these */
	inode->i_flags |= S_NOATIME | S_NOCMTIME;
	inode->i_mapping->a_ops = &vboxsf_reg_aops;

	if (SHFL_IS_DIRECTORY(attr->mode)) {
		if (sbi->o.dmode_set)
			mode = sbi->o.dmode;
		mode &= ~sbi->o.dmask;
		mode |= S_IFDIR;
		if (!reinit) {
			inode->i_op = &vboxsf_dir_iops;
			inode->i_fop = &vboxsf_dir_fops;
			/*
			 * XXX: this probably should be set to the number of entries
			 * in the directory plus two (. ..)
			 */
			set_nlink(inode, 1);
		} else if (!S_ISDIR(inode->i_mode))
			return -ESTALE;
		inode->i_mode = mode;
	} else if (SHFL_IS_SYMLINK(attr->mode)) {
		if (sbi->o.fmode_set)
			mode = sbi->o.fmode;
		mode &= ~sbi->o.fmask;
		mode |= S_IFLNK;
		if (!reinit) {
			inode->i_op = &vboxsf_lnk_iops;
			set_nlink(inode, 1);
		} else if (!S_ISLNK(inode->i_mode))
			return -ESTALE;
		inode->i_mode = mode;
	} else {
		if (sbi->o.fmode_set)
			mode = sbi->o.fmode;
		mode &= ~sbi->o.fmask;
		mode |= S_IFREG;
		if (!reinit) {
			inode->i_op = &vboxsf_reg_iops;
			inode->i_fop = &vboxsf_reg_fops;
			set_nlink(inode, 1);
		} else if (!S_ISREG(inode->i_mode))
			return -ESTALE;
		inode->i_mode = mode;
	}

	inode->i_uid = sbi->o.uid;
	inode->i_gid = sbi->o.gid;

	inode->i_size = info->size;
	inode->i_blkbits = 12;
	/* i_blocks always in units of 512 bytes! */
	allocated = info->allocated + 511;
	do_div(allocated, 512);
	inode->i_blocks = allocated;

	inode->i_atime = ns_to_timespec64(
				 info->access_time.ns_relative_to_unix_epoch);
	inode->i_ctime = ns_to_timespec64(
				 info->change_time.ns_relative_to_unix_epoch);
	inode->i_mtime = ns_to_timespec64(
			   info->modification_time.ns_relative_to_unix_epoch);
	return 0;
}

int vboxsf_create_at_dentry(struct dentry *dentry,
			    struct shfl_createparms *params)
{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
	struct shfl_string *path;
	int err;

	path = vboxsf_path_from_dentry(sbi, dentry);
	if (IS_ERR(path))
		return PTR_ERR(path);

	err = vboxsf_create(sbi->root, path, params);
	__putname(path);

	return err;
}

int vboxsf_stat(struct vboxsf_sbi *sbi, struct shfl_string *path,
		struct shfl_fsobjinfo *info)
{
	struct shfl_createparms params = {};
	int err;

	params.handle = SHFL_HANDLE_NIL;
	params.create_flags = SHFL_CF_LOOKUP | SHFL_CF_ACT_FAIL_IF_NEW;

	err = vboxsf_create(sbi->root, path, &params);
	if (err)
		return err;

	if (params.result != SHFL_FILE_EXISTS)
		return -ENOENT;

	if (info)
		*info = params.info;

	return 0;
}

int vboxsf_stat_dentry(struct dentry *dentry, struct shfl_fsobjinfo *info)
{
	struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
	struct shfl_string *path;
	int err;

	path = vboxsf_path_from_dentry(sbi, dentry);
	if (IS_ERR(path))
		return PTR_ERR(path);

	err = vboxsf_stat(sbi, path, info);
	__putname(path);
	return err;
}

int vboxsf_inode_revalidate(struct dentry *dentry)
{
	struct vboxsf_sbi *sbi;
	struct vboxsf_inode *sf_i;
	struct shfl_fsobjinfo info;
	struct timespec64 prev_mtime;
	struct inode *inode;
	int err;

	if (!dentry || !d_really_is_positive(dentry))
		return -EINVAL;

	inode = d_inode(dentry);
	prev_mtime = inode->i_mtime;
	sf_i = VBOXSF_I(inode);
	sbi = VBOXSF_SBI(dentry->d_sb);
	if (!sf_i->force_restat) {
		if (time_before(jiffies, dentry->d_time + sbi->o.ttl))
			return 0;
	}

	err = vboxsf_stat_dentry(dentry, &info);
	if (err)
		return err;

	dentry->d_time = jiffies;
	sf_i->force_restat = 0;
	err = vboxsf_init_inode(sbi, inode, &info, true);
	if (err)
		return err;

	/*
	 * If the file was changed on the host side we need to invalidate the
	 * page-cache for it.  Note this also gets triggered by our own writes,
	 * this is unavoidable.
	 */
	if (timespec64_compare(&inode->i_mtime, &prev_mtime) > 0)
		invalidate_inode_pages2(inode->i_mapping);

	return 0;
}

int vboxsf_getattr(struct user_namespace *mnt_userns, const struct path *path,
		   struct kstat *kstat, u32 request_mask, unsigned int flags)
{
	int err;
	struct dentry *dentry = path->dentry;
	struct inode *inode = d_inode(dentry);
	struct vboxsf_inode *sf_i = VBOXSF_I(inode);

	switch (flags & AT_STATX_SYNC_TYPE) {
	case AT_STATX_DONT_SYNC:
		err = 0;
		break;
	case AT_STATX_FORCE_SYNC:
		sf_i->force_restat = 1;
		fallthrough;
	default:
		err = vboxsf_inode_revalidate(dentry);
	}
	if (err)
		return err;

	generic_fillattr(&init_user_ns, d_inode(dentry), kstat);
	return 0;
}

int vboxsf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
		   struct iattr *iattr)
{
	struct vboxsf_inode *sf_i = VBOXSF_I(d_inode(dentry));
	struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
	struct shfl_createparms params = {};
	struct shfl_fsobjinfo info = {};
	u32 buf_len;
	int err;

	params.handle = SHFL_HANDLE_NIL;
	params.create_flags = SHFL_CF_ACT_OPEN_IF_EXISTS |
			      SHFL_CF_ACT_FAIL_IF_NEW |
			      SHFL_CF_ACCESS_ATTR_WRITE;

	/* this is at least required for Posix hosts */
	if (iattr->ia_valid & ATTR_SIZE)
		params.create_flags |= SHFL_CF_ACCESS_WRITE;

	err = vboxsf_create_at_dentry(dentry, &params);
	if (err || params.result != SHFL_FILE_EXISTS)
		return err ? err : -ENOENT;

#define mode_set(r) ((iattr->ia_mode & (S_##r)) ? SHFL_UNIX_##r : 0)

	/*
	 * Setting the file size and setting the other attributes has to
	 * be handled separately.
	 */
	if (iattr->ia_valid & (ATTR_MODE | ATTR_ATIME | ATTR_MTIME)) {
		if (iattr->ia_valid & ATTR_MODE) {
			info.attr.mode = mode_set(IRUSR);
			info.attr.mode |= mode_set(IWUSR);
			info.attr.mode |= mode_set(IXUSR);
			info.attr.mode |= mode_set(IRGRP);
			info.attr.mode |= mode_set(IWGRP);
			info.attr.mode |= mode_set(IXGRP);
			info.attr.mode |= mode_set(IROTH);
			info.attr.mode |= mode_set(IWOTH);
			info.attr.mode |= mode_set(IXOTH);

			if (iattr->ia_mode & S_IFDIR)
				info.attr.mode |= SHFL_TYPE_DIRECTORY;
			else
				info.attr.mode |= SHFL_TYPE_FILE;
		}

		if (iattr->ia_valid & ATTR_ATIME)
			info.access_time.ns_relative_to_unix_epoch =
					    timespec64_to_ns(&iattr->ia_atime);

		if (iattr->ia_valid & ATTR_MTIME)
			info.modification_time.ns_relative_to_unix_epoch =
					    timespec64_to_ns(&iattr->ia_mtime);

		/*
		 * Ignore ctime (inode change time) as it can't be set
		 * from userland anyway.
		 */

		buf_len = sizeof(info);
		err = vboxsf_fsinfo(sbi->root, params.handle,
				    SHFL_INFO_SET | SHFL_INFO_FILE, &buf_len,
				    &info);
		if (err) {
			vboxsf_close(sbi->root, params.handle);
			return err;
		}

		/* the host may have given us different attr then requested */
		sf_i->force_restat = 1;
	}

#undef mode_set

	if (iattr->ia_valid & ATTR_SIZE) {
		memset(&info, 0, sizeof(info));
		info.size = iattr->ia_size;
		buf_len = sizeof(info);
		err = vboxsf_fsinfo(sbi->root, params.handle,
				    SHFL_INFO_SET | SHFL_INFO_SIZE, &buf_len,
				    &info);
		if (err) {
			vboxsf_close(sbi->root, params.handle);
			return err;
		}

		/* the host may have given us different attr then requested */
		sf_i->force_restat = 1;
	}

	vboxsf_close(sbi->root, params.handle);

	/* Update the inode with what the host has actually given us. */
	if (sf_i->force_restat)
		vboxsf_inode_revalidate(dentry);

	return 0;
}

/*
 * [dentry] contains string encoded in coding system that corresponds
 * to [sbi]->nls, we must convert it to UTF8 here.
 * Returns a shfl_string allocated through __getname (must be freed using
 * __putname), or an ERR_PTR on error.
 */
struct shfl_string *vboxsf_path_from_dentry(struct vboxsf_sbi *sbi,
					    struct dentry *dentry)
{
	struct shfl_string *shfl_path;
	int path_len, out_len, nb;
	char *buf, *path;
	wchar_t uni;
	u8 *out;

	buf = __getname();
	if (!buf)
		return ERR_PTR(-ENOMEM);

	path = dentry_path_raw(dentry, buf, PATH_MAX);
	if (IS_ERR(path)) {
		__putname(buf);
		return ERR_CAST(path);
	}
	path_len = strlen(path);

	if (sbi->nls) {
		shfl_path = __getname();
		if (!shfl_path) {
			__putname(buf);
			return ERR_PTR(-ENOMEM);
		}

		out = shfl_path->string.utf8;
		out_len = PATH_MAX - SHFLSTRING_HEADER_SIZE - 1;

		while (path_len) {
			nb = sbi->nls->char2uni(path, path_len, &uni);
			if (nb < 0) {
				__putname(shfl_path);
				__putname(buf);
				return ERR_PTR(-EINVAL);
			}
			path += nb;
			path_len -= nb;

			nb = utf32_to_utf8(uni, out, out_len);
			if (nb < 0) {
				__putname(shfl_path);
				__putname(buf);
				return ERR_PTR(-ENAMETOOLONG);
			}
			out += nb;
			out_len -= nb;
		}
		*out = 0;
		shfl_path->length = out - shfl_path->string.utf8;
		shfl_path->size = shfl_path->length + 1;
		__putname(buf);
	} else {
		if ((SHFLSTRING_HEADER_SIZE + path_len + 1) > PATH_MAX) {
			__putname(buf);
			return ERR_PTR(-ENAMETOOLONG);
		}
		/*
		 * dentry_path stores the name at the end of buf, but the
		 * shfl_string string we return must be properly aligned.
		 */
		shfl_path = (struct shfl_string *)buf;
		memmove(shfl_path->string.utf8, path, path_len);
		shfl_path->string.utf8[path_len] = 0;
		shfl_path->length = path_len;
		shfl_path->size = path_len + 1;
	}

	return shfl_path;
}

int vboxsf_nlscpy(struct vboxsf_sbi *sbi, char *name, size_t name_bound_len,
		  const unsigned char *utf8_name, size_t utf8_len)
{
	const char *in;
	char *out;
	size_t out_len;
	size_t out_bound_len;
	size_t in_bound_len;

	in = utf8_name;
	in_bound_len = utf8_len;

	out = name;
	out_len = 0;
	/* Reserve space for terminating 0 */
	out_bound_len = name_bound_len - 1;

	while (in_bound_len) {
		int nb;
		unicode_t uni;

		nb = utf8_to_utf32(in, in_bound_len, &uni);
		if (nb < 0)
			return -EINVAL;

		in += nb;
		in_bound_len -= nb;

		nb = sbi->nls->uni2char(uni, out, out_bound_len);
		if (nb < 0)
			return nb;

		out += nb;
		out_bound_len -= nb;
		out_len += nb;
	}

	*out = 0;

	return 0;
}

static struct vboxsf_dir_buf *vboxsf_dir_buf_alloc(struct list_head *list)
{
	struct vboxsf_dir_buf *b;

	b = kmalloc(sizeof(*b), GFP_KERNEL);
	if (!b)
		return NULL;

	b->buf = kmalloc(DIR_BUFFER_SIZE, GFP_KERNEL);
	if (!b->buf) {
		kfree(b);
		return NULL;
	}

	b->entries = 0;
	b->used = 0;
	b->free = DIR_BUFFER_SIZE;
	list_add(&b->head, list);

	return b;
}

static void vboxsf_dir_buf_free(struct vboxsf_dir_buf *b)
{
	list_del(&b->head);
	kfree(b->buf);
	kfree(b);
}

struct vboxsf_dir_info *vboxsf_dir_info_alloc(void)
{
	struct vboxsf_dir_info *p;

	p = kmalloc(sizeof(*p), GFP_KERNEL);
	if (!p)
		return NULL;

	INIT_LIST_HEAD(&p->info_list);
	return p;
}

void vboxsf_dir_info_free(struct vboxsf_dir_info *p)
{
	struct list_head *list, *pos, *tmp;

	list = &p->info_list;
	list_for_each_safe(pos, tmp, list) {
		struct vboxsf_dir_buf *b;

		b = list_entry(pos, struct vboxsf_dir_buf, head);
		vboxsf_dir_buf_free(b);
	}
	kfree(p);
}

int vboxsf_dir_read_all(struct vboxsf_sbi *sbi, struct vboxsf_dir_info *sf_d,
			u64 handle)
{
	struct vboxsf_dir_buf *b;
	u32 entries, size;
	int err = 0;
	void *buf;

	/* vboxsf_dirinfo returns 1 on end of dir */
	while (err == 0) {
		b = vboxsf_dir_buf_alloc(&sf_d->info_list);
		if (!b) {
			err = -ENOMEM;
			break;
		}

		buf = b->buf;
		size = b->free;

		err = vboxsf_dirinfo(sbi->root, handle, NULL, 0, 0,
				     &size, buf, &entries);
		if (err < 0)
			break;

		b->entries += entries;
		b->free -= size;
		b->used += size;
	}

	if (b && b->used == 0)
		vboxsf_dir_buf_free(b);

	/* -EILSEQ means the host could not translate a filename, ignore */
	if (err > 0 || err == -EILSEQ)
		err = 0;

	return err;
}