stat.c 11 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
/*
 *  linux/fs/stat.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

7
#include <linux/export.h>
Linus Torvalds's avatar
Linus Torvalds committed
8
9
10
11
12
13
14
15
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/highuid.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/syscalls.h>
16
#include <linux/pagemap.h>
Linus Torvalds's avatar
Linus Torvalds committed
17
18
19
20
21
22
23
24
25
26
27
28
29

#include <asm/uaccess.h>
#include <asm/unistd.h>

void generic_fillattr(struct inode *inode, struct kstat *stat)
{
	stat->dev = inode->i_sb->s_dev;
	stat->ino = inode->i_ino;
	stat->mode = inode->i_mode;
	stat->nlink = inode->i_nlink;
	stat->uid = inode->i_uid;
	stat->gid = inode->i_gid;
	stat->rdev = inode->i_rdev;
30
	stat->size = i_size_read(inode);
Linus Torvalds's avatar
Linus Torvalds committed
31
32
33
	stat->atime = inode->i_atime;
	stat->mtime = inode->i_mtime;
	stat->ctime = inode->i_ctime;
34
	stat->blksize = (1 << inode->i_blkbits);
35
	stat->blocks = inode->i_blocks;
Linus Torvalds's avatar
Linus Torvalds committed
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
}

EXPORT_SYMBOL(generic_fillattr);

int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
	struct inode *inode = dentry->d_inode;
	int retval;

	retval = security_inode_getattr(mnt, dentry);
	if (retval)
		return retval;

	if (inode->i_op->getattr)
		return inode->i_op->getattr(mnt, dentry, stat);

	generic_fillattr(inode, stat);
	return 0;
}

EXPORT_SYMBOL(vfs_getattr);

int vfs_fstat(unsigned int fd, struct kstat *stat)
{
60
	struct fd f = fdget_raw(fd);
Linus Torvalds's avatar
Linus Torvalds committed
61
62
	int error = -EBADF;

63
64
65
66
	if (f.file) {
		error = vfs_getattr(f.file->f_path.mnt, f.file->f_path.dentry,
				    stat);
		fdput(f);
Linus Torvalds's avatar
Linus Torvalds committed
67
68
69
70
71
	}
	return error;
}
EXPORT_SYMBOL(vfs_fstat);

72
73
int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
		int flag)
74
{
75
	struct path path;
76
	int error = -EINVAL;
77
	int lookup_flags = 0;
78

79
80
	if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
		      AT_EMPTY_PATH)) != 0)
81
82
		goto out;

83
84
	if (!(flag & AT_SYMLINK_NOFOLLOW))
		lookup_flags |= LOOKUP_FOLLOW;
85
86
	if (flag & AT_EMPTY_PATH)
		lookup_flags |= LOOKUP_EMPTY;
87
88
89
90
91
92
93

	error = user_path_at(dfd, filename, lookup_flags, &path);
	if (error)
		goto out;

	error = vfs_getattr(path.mnt, path.dentry, stat);
	path_put(&path);
94
95
96
97
98
out:
	return error;
}
EXPORT_SYMBOL(vfs_fstatat);

99
int vfs_stat(const char __user *name, struct kstat *stat)
100
101
102
103
104
{
	return vfs_fstatat(AT_FDCWD, name, stat, 0);
}
EXPORT_SYMBOL(vfs_stat);

105
int vfs_lstat(const char __user *name, struct kstat *stat)
106
107
108
109
110
{
	return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
}
EXPORT_SYMBOL(vfs_lstat);

111

Linus Torvalds's avatar
Linus Torvalds committed
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
#ifdef __ARCH_WANT_OLD_STAT

/*
 * For backward compatibility?  Maybe this should be moved
 * into arch/i386 instead?
 */
static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
{
	static int warncount = 5;
	struct __old_kernel_stat tmp;
	
	if (warncount > 0) {
		warncount--;
		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
			current->comm);
	} else if (warncount < 0) {
		/* it's laughable, but... */
		warncount = 0;
	}

	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
	tmp.st_dev = old_encode_dev(stat->dev);
	tmp.st_ino = stat->ino;
135
136
	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
		return -EOVERFLOW;
Linus Torvalds's avatar
Linus Torvalds committed
137
138
139
140
	tmp.st_mode = stat->mode;
	tmp.st_nlink = stat->nlink;
	if (tmp.st_nlink != stat->nlink)
		return -EOVERFLOW;
141
142
	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
Linus Torvalds's avatar
Linus Torvalds committed
143
144
145
146
147
148
149
150
151
152
153
154
	tmp.st_rdev = old_encode_dev(stat->rdev);
#if BITS_PER_LONG == 32
	if (stat->size > MAX_NON_LFS)
		return -EOVERFLOW;
#endif	
	tmp.st_size = stat->size;
	tmp.st_atime = stat->atime.tv_sec;
	tmp.st_mtime = stat->mtime.tv_sec;
	tmp.st_ctime = stat->ctime.tv_sec;
	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}

155
156
SYSCALL_DEFINE2(stat, const char __user *, filename,
		struct __old_kernel_stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
157
158
{
	struct kstat stat;
159
	int error;
Linus Torvalds's avatar
Linus Torvalds committed
160

161
162
163
	error = vfs_stat(filename, &stat);
	if (error)
		return error;
Linus Torvalds's avatar
Linus Torvalds committed
164

165
	return cp_old_stat(&stat, statbuf);
Linus Torvalds's avatar
Linus Torvalds committed
166
}
167

168
169
SYSCALL_DEFINE2(lstat, const char __user *, filename,
		struct __old_kernel_stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
170
171
{
	struct kstat stat;
172
	int error;
Linus Torvalds's avatar
Linus Torvalds committed
173

174
175
176
	error = vfs_lstat(filename, &stat);
	if (error)
		return error;
Linus Torvalds's avatar
Linus Torvalds committed
177

178
	return cp_old_stat(&stat, statbuf);
Linus Torvalds's avatar
Linus Torvalds committed
179
}
180
181

SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
182
183
184
185
186
187
188
189
190
191
192
193
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);

	if (!error)
		error = cp_old_stat(&stat, statbuf);

	return error;
}

#endif /* __ARCH_WANT_OLD_STAT */

194
195
196
197
198
199
200
201
202
#if BITS_PER_LONG == 32
#  define choose_32_64(a,b) a
#else
#  define choose_32_64(a,b) b
#endif

#define valid_dev(x)  choose_32_64(old_valid_dev,new_valid_dev)(x)
#define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)

203
204
205
206
#ifndef INIT_STRUCT_STAT_PADDING
#  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
#endif

Linus Torvalds's avatar
Linus Torvalds committed
207
208
209
210
static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
{
	struct stat tmp;

211
	if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))
Linus Torvalds's avatar
Linus Torvalds committed
212
		return -EOVERFLOW;
213
214
#if BITS_PER_LONG == 32
	if (stat->size > MAX_NON_LFS)
Linus Torvalds's avatar
Linus Torvalds committed
215
216
217
		return -EOVERFLOW;
#endif

218
	INIT_STRUCT_STAT_PADDING(tmp);
219
	tmp.st_dev = encode_dev(stat->dev);
Linus Torvalds's avatar
Linus Torvalds committed
220
	tmp.st_ino = stat->ino;
221
222
	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
		return -EOVERFLOW;
Linus Torvalds's avatar
Linus Torvalds committed
223
224
225
226
	tmp.st_mode = stat->mode;
	tmp.st_nlink = stat->nlink;
	if (tmp.st_nlink != stat->nlink)
		return -EOVERFLOW;
227
228
	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
229
	tmp.st_rdev = encode_dev(stat->rdev);
Linus Torvalds's avatar
Linus Torvalds committed
230
231
232
233
234
235
236
237
238
239
240
241
242
243
	tmp.st_size = stat->size;
	tmp.st_atime = stat->atime.tv_sec;
	tmp.st_mtime = stat->mtime.tv_sec;
	tmp.st_ctime = stat->ctime.tv_sec;
#ifdef STAT_HAVE_NSEC
	tmp.st_atime_nsec = stat->atime.tv_nsec;
	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
#endif
	tmp.st_blocks = stat->blocks;
	tmp.st_blksize = stat->blksize;
	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}

244
245
SYSCALL_DEFINE2(newstat, const char __user *, filename,
		struct stat __user *, statbuf)
246
247
{
	struct kstat stat;
248
	int error = vfs_stat(filename, &stat);
249

250
251
252
	if (error)
		return error;
	return cp_new_stat(&stat, statbuf);
253
254
}

255
256
SYSCALL_DEFINE2(newlstat, const char __user *, filename,
		struct stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
257
258
{
	struct kstat stat;
259
	int error;
Linus Torvalds's avatar
Linus Torvalds committed
260

261
262
263
	error = vfs_lstat(filename, &stat);
	if (error)
		return error;
Linus Torvalds's avatar
Linus Torvalds committed
264

265
	return cp_new_stat(&stat, statbuf);
Linus Torvalds's avatar
Linus Torvalds committed
266
}
267

268
#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
269
SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
270
		struct stat __user *, statbuf, int, flag)
Linus Torvalds's avatar
Linus Torvalds committed
271
272
{
	struct kstat stat;
273
	int error;
Linus Torvalds's avatar
Linus Torvalds committed
274

275
276
277
278
	error = vfs_fstatat(dfd, filename, &stat, flag);
	if (error)
		return error;
	return cp_new_stat(&stat, statbuf);
Linus Torvalds's avatar
Linus Torvalds committed
279
}
Ulrich Drepper's avatar
Ulrich Drepper committed
280
#endif
281

282
SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
283
284
285
286
287
288
289
290
291
292
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);

	if (!error)
		error = cp_new_stat(&stat, statbuf);

	return error;
}

293
294
SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
		char __user *, buf, int, bufsiz)
Linus Torvalds's avatar
Linus Torvalds committed
295
{
296
	struct path path;
Linus Torvalds's avatar
Linus Torvalds committed
297
	int error;
298
	int empty = 0;
Linus Torvalds's avatar
Linus Torvalds committed
299
300
301
302

	if (bufsiz <= 0)
		return -EINVAL;

303
	error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);
Linus Torvalds's avatar
Linus Torvalds committed
304
	if (!error) {
305
		struct inode *inode = path.dentry->d_inode;
Linus Torvalds's avatar
Linus Torvalds committed
306

307
		error = empty ? -ENOENT : -EINVAL;
Al Viro's avatar
Al Viro committed
308
		if (inode->i_op->readlink) {
309
			error = security_inode_readlink(path.dentry);
Linus Torvalds's avatar
Linus Torvalds committed
310
			if (!error) {
Al Viro's avatar
Al Viro committed
311
				touch_atime(&path);
312
				error = inode->i_op->readlink(path.dentry,
313
							      buf, bufsiz);
Linus Torvalds's avatar
Linus Torvalds committed
314
315
			}
		}
316
		path_put(&path);
Linus Torvalds's avatar
Linus Torvalds committed
317
318
319
320
	}
	return error;
}

321
322
SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
		int, bufsiz)
323
324
325
326
{
	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
}

Linus Torvalds's avatar
Linus Torvalds committed
327
328
329
330

/* ---------- LFS-64 ----------- */
#ifdef __ARCH_WANT_STAT64

331
332
333
334
#ifndef INIT_STRUCT_STAT64_PADDING
#  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
#endif

Linus Torvalds's avatar
Linus Torvalds committed
335
336
337
338
static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
{
	struct stat64 tmp;

339
	INIT_STRUCT_STAT64_PADDING(tmp);
Linus Torvalds's avatar
Linus Torvalds committed
340
341
342
343
344
345
346
347
348
349
350
#ifdef CONFIG_MIPS
	/* mips has weird padding, so we don't get 64 bits there */
	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
		return -EOVERFLOW;
	tmp.st_dev = new_encode_dev(stat->dev);
	tmp.st_rdev = new_encode_dev(stat->rdev);
#else
	tmp.st_dev = huge_encode_dev(stat->dev);
	tmp.st_rdev = huge_encode_dev(stat->rdev);
#endif
	tmp.st_ino = stat->ino;
351
352
	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
		return -EOVERFLOW;
Linus Torvalds's avatar
Linus Torvalds committed
353
354
355
356
357
#ifdef STAT64_HAS_BROKEN_ST_INO
	tmp.__st_ino = stat->ino;
#endif
	tmp.st_mode = stat->mode;
	tmp.st_nlink = stat->nlink;
358
359
	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
Linus Torvalds's avatar
Linus Torvalds committed
360
361
362
363
364
365
366
367
368
369
370
371
	tmp.st_atime = stat->atime.tv_sec;
	tmp.st_atime_nsec = stat->atime.tv_nsec;
	tmp.st_mtime = stat->mtime.tv_sec;
	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
	tmp.st_ctime = stat->ctime.tv_sec;
	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
	tmp.st_size = stat->size;
	tmp.st_blocks = stat->blocks;
	tmp.st_blksize = stat->blksize;
	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}

372
373
SYSCALL_DEFINE2(stat64, const char __user *, filename,
		struct stat64 __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
374
375
376
377
378
379
380
381
382
{
	struct kstat stat;
	int error = vfs_stat(filename, &stat);

	if (!error)
		error = cp_new_stat64(&stat, statbuf);

	return error;
}
383

384
385
SYSCALL_DEFINE2(lstat64, const char __user *, filename,
		struct stat64 __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
386
387
388
389
390
391
392
393
394
{
	struct kstat stat;
	int error = vfs_lstat(filename, &stat);

	if (!error)
		error = cp_new_stat64(&stat, statbuf);

	return error;
}
395
396

SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
397
398
399
400
401
402
403
404
405
406
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);

	if (!error)
		error = cp_new_stat64(&stat, statbuf);

	return error;
}

407
SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
408
		struct stat64 __user *, statbuf, int, flag)
Ulrich Drepper's avatar
Ulrich Drepper committed
409
410
{
	struct kstat stat;
411
	int error;
Ulrich Drepper's avatar
Ulrich Drepper committed
412

413
414
415
416
	error = vfs_fstatat(dfd, filename, &stat, flag);
	if (error)
		return error;
	return cp_new_stat64(&stat, statbuf);
Ulrich Drepper's avatar
Ulrich Drepper committed
417
}
Linus Torvalds's avatar
Linus Torvalds committed
418
419
#endif /* __ARCH_WANT_STAT64 */

420
421
/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
void __inode_add_bytes(struct inode *inode, loff_t bytes)
Linus Torvalds's avatar
Linus Torvalds committed
422
423
424
425
426
427
428
429
{
	inode->i_blocks += bytes >> 9;
	bytes &= 511;
	inode->i_bytes += bytes;
	if (inode->i_bytes >= 512) {
		inode->i_blocks++;
		inode->i_bytes -= 512;
	}
430
431
432
433
434
435
}

void inode_add_bytes(struct inode *inode, loff_t bytes)
{
	spin_lock(&inode->i_lock);
	__inode_add_bytes(inode, bytes);
Linus Torvalds's avatar
Linus Torvalds committed
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
	spin_unlock(&inode->i_lock);
}

EXPORT_SYMBOL(inode_add_bytes);

void inode_sub_bytes(struct inode *inode, loff_t bytes)
{
	spin_lock(&inode->i_lock);
	inode->i_blocks -= bytes >> 9;
	bytes &= 511;
	if (inode->i_bytes < bytes) {
		inode->i_blocks--;
		inode->i_bytes += 512;
	}
	inode->i_bytes -= bytes;
	spin_unlock(&inode->i_lock);
}

EXPORT_SYMBOL(inode_sub_bytes);

loff_t inode_get_bytes(struct inode *inode)
{
	loff_t ret;

	spin_lock(&inode->i_lock);
	ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
	spin_unlock(&inode->i_lock);
	return ret;
}

EXPORT_SYMBOL(inode_get_bytes);

void inode_set_bytes(struct inode *inode, loff_t bytes)
{
	/* Caller is here responsible for sufficient locking
	 * (ie. inode->i_lock) */
	inode->i_blocks = bytes >> 9;
	inode->i_bytes = bytes & 511;
}

EXPORT_SYMBOL(inode_set_bytes);