stat.c 10.6 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
/*
 *  linux/fs/stat.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/module.h>
#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
30
31
32
33
34

#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;
	stat->atime = inode->i_atime;
	stat->mtime = inode->i_mtime;
	stat->ctime = inode->i_ctime;
	stat->size = i_size_read(inode);
	stat->blocks = inode->i_blocks;
35
	stat->blksize = (1 << inode->i_blkbits);
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
}

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);

58
int vfs_stat_fd(int dfd, char __user *name, struct kstat *stat)
Linus Torvalds's avatar
Linus Torvalds committed
59
{
60
	struct path path;
Linus Torvalds's avatar
Linus Torvalds committed
61
62
	int error;

63
	error = user_path_at(dfd, name, LOOKUP_FOLLOW, &path);
Linus Torvalds's avatar
Linus Torvalds committed
64
	if (!error) {
65
66
		error = vfs_getattr(path.mnt, path.dentry, stat);
		path_put(&path);
Linus Torvalds's avatar
Linus Torvalds committed
67
68
69
70
	}
	return error;
}

71
72
73
74
75
int vfs_stat(char __user *name, struct kstat *stat)
{
	return vfs_stat_fd(AT_FDCWD, name, stat);
}

Linus Torvalds's avatar
Linus Torvalds committed
76
77
EXPORT_SYMBOL(vfs_stat);

78
int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat)
Linus Torvalds's avatar
Linus Torvalds committed
79
{
80
	struct path path;
Linus Torvalds's avatar
Linus Torvalds committed
81
82
	int error;

83
	error = user_path_at(dfd, name, 0, &path);
Linus Torvalds's avatar
Linus Torvalds committed
84
	if (!error) {
85
86
		error = vfs_getattr(path.mnt, path.dentry, stat);
		path_put(&path);
Linus Torvalds's avatar
Linus Torvalds committed
87
88
89
90
	}
	return error;
}

91
92
93
94
95
int vfs_lstat(char __user *name, struct kstat *stat)
{
	return vfs_lstat_fd(AT_FDCWD, name, stat);
}

Linus Torvalds's avatar
Linus Torvalds committed
96
97
98
99
100
101
102
103
EXPORT_SYMBOL(vfs_lstat);

int vfs_fstat(unsigned int fd, struct kstat *stat)
{
	struct file *f = fget(fd);
	int error = -EBADF;

	if (f) {
104
		error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);
Linus Torvalds's avatar
Linus Torvalds committed
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
		fput(f);
	}
	return error;
}

EXPORT_SYMBOL(vfs_fstat);

#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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
	tmp.st_mode = stat->mode;
	tmp.st_nlink = stat->nlink;
	if (tmp.st_nlink != stat->nlink)
		return -EOVERFLOW;
	SET_UID(tmp.st_uid, stat->uid);
	SET_GID(tmp.st_gid, stat->gid);
	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
SYSCALL_DEFINE2(stat, char __user *, filename, struct __old_kernel_stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
156
157
{
	struct kstat stat;
158
	int error = vfs_stat_fd(AT_FDCWD, filename, &stat);
Linus Torvalds's avatar
Linus Torvalds committed
159
160
161
162
163
164

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

	return error;
}
165
166

SYSCALL_DEFINE2(lstat, char __user *, filename, struct __old_kernel_stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
167
168
{
	struct kstat stat;
169
	int error = vfs_lstat_fd(AT_FDCWD, filename, &stat);
Linus Torvalds's avatar
Linus Torvalds committed
170
171
172
173
174
175

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

	return error;
}
176
177

SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
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
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);

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

	return error;
}

#endif /* __ARCH_WANT_OLD_STAT */

static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
{
	struct stat tmp;

#if BITS_PER_LONG == 32
	if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
		return -EOVERFLOW;
#else
	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
		return -EOVERFLOW;
#endif

	memset(&tmp, 0, sizeof(tmp));
#if BITS_PER_LONG == 32
	tmp.st_dev = old_encode_dev(stat->dev);
#else
	tmp.st_dev = new_encode_dev(stat->dev);
#endif
	tmp.st_ino = stat->ino;
209
210
	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
		return -EOVERFLOW;
Linus Torvalds's avatar
Linus Torvalds committed
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
	tmp.st_mode = stat->mode;
	tmp.st_nlink = stat->nlink;
	if (tmp.st_nlink != stat->nlink)
		return -EOVERFLOW;
	SET_UID(tmp.st_uid, stat->uid);
	SET_GID(tmp.st_gid, stat->gid);
#if BITS_PER_LONG == 32
	tmp.st_rdev = old_encode_dev(stat->rdev);
#else
	tmp.st_rdev = new_encode_dev(stat->rdev);
#endif
#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;
#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;
}

240
SYSCALL_DEFINE2(newstat, char __user *, filename, struct stat __user *, statbuf)
241
242
243
244
245
246
247
248
249
250
{
	struct kstat stat;
	int error = vfs_stat_fd(AT_FDCWD, filename, &stat);

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

	return error;
}

251
SYSCALL_DEFINE2(newlstat, char __user *, filename, struct stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
252
253
{
	struct kstat stat;
254
	int error = vfs_lstat_fd(AT_FDCWD, filename, &stat);
Linus Torvalds's avatar
Linus Torvalds committed
255
256
257
258
259
260

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

	return error;
}
261

262
#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
263
264
SYSCALL_DEFINE4(newfstatat, int, dfd, char __user *, filename,
		struct stat __user *, statbuf, int, flag)
Linus Torvalds's avatar
Linus Torvalds committed
265
266
{
	struct kstat stat;
267
268
269
270
271
272
273
274
275
	int error = -EINVAL;

	if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
		goto out;

	if (flag & AT_SYMLINK_NOFOLLOW)
		error = vfs_lstat_fd(dfd, filename, &stat);
	else
		error = vfs_stat_fd(dfd, filename, &stat);
Linus Torvalds's avatar
Linus Torvalds committed
276
277
278
279

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

280
out:
Linus Torvalds's avatar
Linus Torvalds committed
281
282
	return error;
}
Ulrich Drepper's avatar
Ulrich Drepper committed
283
#endif
284

285
SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
286
287
288
289
290
291
292
293
294
295
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);

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

	return error;
}

296
297
SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
		char __user *, buf, int, bufsiz)
Linus Torvalds's avatar
Linus Torvalds committed
298
{
299
	struct path path;
Linus Torvalds's avatar
Linus Torvalds committed
300
301
302
303
304
	int error;

	if (bufsiz <= 0)
		return -EINVAL;

305
	error = user_path_at(dfd, pathname, 0, &path);
Linus Torvalds's avatar
Linus Torvalds committed
306
	if (!error) {
307
		struct inode *inode = path.dentry->d_inode;
Linus Torvalds's avatar
Linus Torvalds committed
308
309

		error = -EINVAL;
Al Viro's avatar
Al Viro committed
310
		if (inode->i_op->readlink) {
311
			error = security_inode_readlink(path.dentry);
Linus Torvalds's avatar
Linus Torvalds committed
312
			if (!error) {
313
314
				touch_atime(path.mnt, path.dentry);
				error = inode->i_op->readlink(path.dentry,
315
							      buf, bufsiz);
Linus Torvalds's avatar
Linus Torvalds committed
316
317
			}
		}
318
		path_put(&path);
Linus Torvalds's avatar
Linus Torvalds committed
319
320
321
322
	}
	return error;
}

323
324
SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
		int, bufsiz)
325
326
327
328
{
	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
}

Linus Torvalds's avatar
Linus Torvalds committed
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348

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

static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
{
	struct stat64 tmp;

	memset(&tmp, 0, sizeof(struct stat64));
#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;
349
350
	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
		return -EOVERFLOW;
Linus Torvalds's avatar
Linus Torvalds committed
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
#ifdef STAT64_HAS_BROKEN_ST_INO
	tmp.__st_ino = stat->ino;
#endif
	tmp.st_mode = stat->mode;
	tmp.st_nlink = stat->nlink;
	tmp.st_uid = stat->uid;
	tmp.st_gid = stat->gid;
	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;
}

370
SYSCALL_DEFINE2(stat64, char __user *, filename, struct stat64 __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
371
372
373
374
375
376
377
378
379
{
	struct kstat stat;
	int error = vfs_stat(filename, &stat);

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

	return error;
}
380
381

SYSCALL_DEFINE2(lstat64, char __user *, filename, struct stat64 __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
382
383
384
385
386
387
388
389
390
{
	struct kstat stat;
	int error = vfs_lstat(filename, &stat);

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

	return error;
}
391
392

SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
Linus Torvalds's avatar
Linus Torvalds committed
393
394
395
396
397
398
399
400
401
402
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);

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

	return error;
}

403
404
SYSCALL_DEFINE4(fstatat64, int, dfd, char __user *, filename,
		struct stat64 __user *, statbuf, int, flag)
Ulrich Drepper's avatar
Ulrich Drepper committed
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
{
	struct kstat stat;
	int error = -EINVAL;

	if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
		goto out;

	if (flag & AT_SYMLINK_NOFOLLOW)
		error = vfs_lstat_fd(dfd, filename, &stat);
	else
		error = vfs_stat_fd(dfd, filename, &stat);

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

out:
	return error;
}
Linus Torvalds's avatar
Linus Torvalds committed
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
#endif /* __ARCH_WANT_STAT64 */

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