Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1/*
2 * linux/fs/stat.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/module.h>
8#include <linux/mm.h>
9#include <linux/errno.h>
10#include <linux/file.h>
11#include <linux/highuid.h>
12#include <linux/fs.h>
13#include <linux/namei.h>
14#include <linux/security.h>
15#include <linux/syscalls.h>
16#include <linux/pagemap.h>
17
18#include <asm/uaccess.h>
19#include <asm/unistd.h>
20
21void generic_fillattr(struct inode *inode, struct kstat *stat)
22{
23 stat->dev = inode->i_sb->s_dev;
24 stat->ino = inode->i_ino;
25 stat->mode = inode->i_mode;
26 stat->nlink = inode->i_nlink;
27 stat->uid = inode->i_uid;
28 stat->gid = inode->i_gid;
29 stat->rdev = inode->i_rdev;
30 stat->atime = inode->i_atime;
31 stat->mtime = inode->i_mtime;
32 stat->ctime = inode->i_ctime;
33 stat->size = i_size_read(inode);
34 stat->blocks = inode->i_blocks;
35 stat->blksize = (1 << inode->i_blkbits);
36}
37
38EXPORT_SYMBOL(generic_fillattr);
39
40int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
41{
42 struct inode *inode = dentry->d_inode;
43 int retval;
44
45 retval = security_inode_getattr(mnt, dentry);
46 if (retval)
47 return retval;
48
49 if (inode->i_op->getattr)
50 return inode->i_op->getattr(mnt, dentry, stat);
51
52 generic_fillattr(inode, stat);
53 return 0;
54}
55
56EXPORT_SYMBOL(vfs_getattr);
57
58int vfs_fstat(unsigned int fd, struct kstat *stat)
59{
60 struct file *f = fget(fd);
61 int error = -EBADF;
62
63 if (f) {
64 error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);
65 fput(f);
66 }
67 return error;
68}
69EXPORT_SYMBOL(vfs_fstat);
70
71int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
72 int flag)
73{
74 struct path path;
75 int error = -EINVAL;
76 int lookup_flags = 0;
77
78 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
79 AT_EMPTY_PATH)) != 0)
80 goto out;
81
82 if (!(flag & AT_SYMLINK_NOFOLLOW))
83 lookup_flags |= LOOKUP_FOLLOW;
84 if (flag & AT_NO_AUTOMOUNT)
85 lookup_flags |= LOOKUP_NO_AUTOMOUNT;
86 if (flag & AT_EMPTY_PATH)
87 lookup_flags |= LOOKUP_EMPTY;
88
89 error = user_path_at(dfd, filename, lookup_flags, &path);
90 if (error)
91 goto out;
92
93 error = vfs_getattr(path.mnt, path.dentry, stat);
94 path_put(&path);
95out:
96 return error;
97}
98EXPORT_SYMBOL(vfs_fstatat);
99
100int vfs_stat(const char __user *name, struct kstat *stat)
101{
102 return vfs_fstatat(AT_FDCWD, name, stat, 0);
103}
104EXPORT_SYMBOL(vfs_stat);
105
106int vfs_lstat(const char __user *name, struct kstat *stat)
107{
108 return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
109}
110EXPORT_SYMBOL(vfs_lstat);
111
112
113#ifdef __ARCH_WANT_OLD_STAT
114
115/*
116 * For backward compatibility? Maybe this should be moved
117 * into arch/i386 instead?
118 */
119static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
120{
121 static int warncount = 5;
122 struct __old_kernel_stat tmp;
123
124 if (warncount > 0) {
125 warncount--;
126 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
127 current->comm);
128 } else if (warncount < 0) {
129 /* it's laughable, but... */
130 warncount = 0;
131 }
132
133 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
134 tmp.st_dev = old_encode_dev(stat->dev);
135 tmp.st_ino = stat->ino;
136 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
137 return -EOVERFLOW;
138 tmp.st_mode = stat->mode;
139 tmp.st_nlink = stat->nlink;
140 if (tmp.st_nlink != stat->nlink)
141 return -EOVERFLOW;
142 SET_UID(tmp.st_uid, stat->uid);
143 SET_GID(tmp.st_gid, stat->gid);
144 tmp.st_rdev = old_encode_dev(stat->rdev);
145#if BITS_PER_LONG == 32
146 if (stat->size > MAX_NON_LFS)
147 return -EOVERFLOW;
148#endif
149 tmp.st_size = stat->size;
150 tmp.st_atime = stat->atime.tv_sec;
151 tmp.st_mtime = stat->mtime.tv_sec;
152 tmp.st_ctime = stat->ctime.tv_sec;
153 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
154}
155
156SYSCALL_DEFINE2(stat, const char __user *, filename,
157 struct __old_kernel_stat __user *, statbuf)
158{
159 struct kstat stat;
160 int error;
161
162 error = vfs_stat(filename, &stat);
163 if (error)
164 return error;
165
166 return cp_old_stat(&stat, statbuf);
167}
168
169SYSCALL_DEFINE2(lstat, const char __user *, filename,
170 struct __old_kernel_stat __user *, statbuf)
171{
172 struct kstat stat;
173 int error;
174
175 error = vfs_lstat(filename, &stat);
176 if (error)
177 return error;
178
179 return cp_old_stat(&stat, statbuf);
180}
181
182SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
183{
184 struct kstat stat;
185 int error = vfs_fstat(fd, &stat);
186
187 if (!error)
188 error = cp_old_stat(&stat, statbuf);
189
190 return error;
191}
192
193#endif /* __ARCH_WANT_OLD_STAT */
194
195static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
196{
197 struct stat tmp;
198
199#if BITS_PER_LONG == 32
200 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
201 return -EOVERFLOW;
202#else
203 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
204 return -EOVERFLOW;
205#endif
206
207 memset(&tmp, 0, sizeof(tmp));
208#if BITS_PER_LONG == 32
209 tmp.st_dev = old_encode_dev(stat->dev);
210#else
211 tmp.st_dev = new_encode_dev(stat->dev);
212#endif
213 tmp.st_ino = stat->ino;
214 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
215 return -EOVERFLOW;
216 tmp.st_mode = stat->mode;
217 tmp.st_nlink = stat->nlink;
218 if (tmp.st_nlink != stat->nlink)
219 return -EOVERFLOW;
220 SET_UID(tmp.st_uid, stat->uid);
221 SET_GID(tmp.st_gid, stat->gid);
222#if BITS_PER_LONG == 32
223 tmp.st_rdev = old_encode_dev(stat->rdev);
224#else
225 tmp.st_rdev = new_encode_dev(stat->rdev);
226#endif
227#if BITS_PER_LONG == 32
228 if (stat->size > MAX_NON_LFS)
229 return -EOVERFLOW;
230#endif
231 tmp.st_size = stat->size;
232 tmp.st_atime = stat->atime.tv_sec;
233 tmp.st_mtime = stat->mtime.tv_sec;
234 tmp.st_ctime = stat->ctime.tv_sec;
235#ifdef STAT_HAVE_NSEC
236 tmp.st_atime_nsec = stat->atime.tv_nsec;
237 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
238 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
239#endif
240 tmp.st_blocks = stat->blocks;
241 tmp.st_blksize = stat->blksize;
242 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
243}
244
245SYSCALL_DEFINE2(newstat, const char __user *, filename,
246 struct stat __user *, statbuf)
247{
248 struct kstat stat;
249 int error = vfs_stat(filename, &stat);
250
251 if (error)
252 return error;
253 return cp_new_stat(&stat, statbuf);
254}
255
256SYSCALL_DEFINE2(newlstat, const char __user *, filename,
257 struct stat __user *, statbuf)
258{
259 struct kstat stat;
260 int error;
261
262 error = vfs_lstat(filename, &stat);
263 if (error)
264 return error;
265
266 return cp_new_stat(&stat, statbuf);
267}
268
269#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
270SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
271 struct stat __user *, statbuf, int, flag)
272{
273 struct kstat stat;
274 int error;
275
276 error = vfs_fstatat(dfd, filename, &stat, flag);
277 if (error)
278 return error;
279 return cp_new_stat(&stat, statbuf);
280}
281#endif
282
283SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
284{
285 struct kstat stat;
286 int error = vfs_fstat(fd, &stat);
287
288 if (!error)
289 error = cp_new_stat(&stat, statbuf);
290
291 return error;
292}
293
294SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
295 char __user *, buf, int, bufsiz)
296{
297 struct path path;
298 int error;
299
300 if (bufsiz <= 0)
301 return -EINVAL;
302
303 error = user_path_at(dfd, pathname, LOOKUP_EMPTY, &path);
304 if (!error) {
305 struct inode *inode = path.dentry->d_inode;
306
307 error = -EINVAL;
308 if (inode->i_op->readlink) {
309 error = security_inode_readlink(path.dentry);
310 if (!error) {
311 touch_atime(path.mnt, path.dentry);
312 error = inode->i_op->readlink(path.dentry,
313 buf, bufsiz);
314 }
315 }
316 path_put(&path);
317 }
318 return error;
319}
320
321SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
322 int, bufsiz)
323{
324 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
325}
326
327
328/* ---------- LFS-64 ----------- */
329#ifdef __ARCH_WANT_STAT64
330
331static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
332{
333 struct stat64 tmp;
334
335 memset(&tmp, 0, sizeof(struct stat64));
336#ifdef CONFIG_MIPS
337 /* mips has weird padding, so we don't get 64 bits there */
338 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
339 return -EOVERFLOW;
340 tmp.st_dev = new_encode_dev(stat->dev);
341 tmp.st_rdev = new_encode_dev(stat->rdev);
342#else
343 tmp.st_dev = huge_encode_dev(stat->dev);
344 tmp.st_rdev = huge_encode_dev(stat->rdev);
345#endif
346 tmp.st_ino = stat->ino;
347 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
348 return -EOVERFLOW;
349#ifdef STAT64_HAS_BROKEN_ST_INO
350 tmp.__st_ino = stat->ino;
351#endif
352 tmp.st_mode = stat->mode;
353 tmp.st_nlink = stat->nlink;
354 tmp.st_uid = stat->uid;
355 tmp.st_gid = stat->gid;
356 tmp.st_atime = stat->atime.tv_sec;
357 tmp.st_atime_nsec = stat->atime.tv_nsec;
358 tmp.st_mtime = stat->mtime.tv_sec;
359 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
360 tmp.st_ctime = stat->ctime.tv_sec;
361 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
362 tmp.st_size = stat->size;
363 tmp.st_blocks = stat->blocks;
364 tmp.st_blksize = stat->blksize;
365 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
366}
367
368SYSCALL_DEFINE2(stat64, const char __user *, filename,
369 struct stat64 __user *, statbuf)
370{
371 struct kstat stat;
372 int error = vfs_stat(filename, &stat);
373
374 if (!error)
375 error = cp_new_stat64(&stat, statbuf);
376
377 return error;
378}
379
380SYSCALL_DEFINE2(lstat64, const char __user *, filename,
381 struct stat64 __user *, statbuf)
382{
383 struct kstat stat;
384 int error = vfs_lstat(filename, &stat);
385
386 if (!error)
387 error = cp_new_stat64(&stat, statbuf);
388
389 return error;
390}
391
392SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
393{
394 struct kstat stat;
395 int error = vfs_fstat(fd, &stat);
396
397 if (!error)
398 error = cp_new_stat64(&stat, statbuf);
399
400 return error;
401}
402
403SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
404 struct stat64 __user *, statbuf, int, flag)
405{
406 struct kstat stat;
407 int error;
408
409 error = vfs_fstatat(dfd, filename, &stat, flag);
410 if (error)
411 return error;
412 return cp_new_stat64(&stat, statbuf);
413}
414#endif /* __ARCH_WANT_STAT64 */
415
416/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
417void __inode_add_bytes(struct inode *inode, loff_t bytes)
418{
419 inode->i_blocks += bytes >> 9;
420 bytes &= 511;
421 inode->i_bytes += bytes;
422 if (inode->i_bytes >= 512) {
423 inode->i_blocks++;
424 inode->i_bytes -= 512;
425 }
426}
427
428void inode_add_bytes(struct inode *inode, loff_t bytes)
429{
430 spin_lock(&inode->i_lock);
431 __inode_add_bytes(inode, bytes);
432 spin_unlock(&inode->i_lock);
433}
434
435EXPORT_SYMBOL(inode_add_bytes);
436
437void inode_sub_bytes(struct inode *inode, loff_t bytes)
438{
439 spin_lock(&inode->i_lock);
440 inode->i_blocks -= bytes >> 9;
441 bytes &= 511;
442 if (inode->i_bytes < bytes) {
443 inode->i_blocks--;
444 inode->i_bytes += 512;
445 }
446 inode->i_bytes -= bytes;
447 spin_unlock(&inode->i_lock);
448}
449
450EXPORT_SYMBOL(inode_sub_bytes);
451
452loff_t inode_get_bytes(struct inode *inode)
453{
454 loff_t ret;
455
456 spin_lock(&inode->i_lock);
457 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
458 spin_unlock(&inode->i_lock);
459 return ret;
460}
461
462EXPORT_SYMBOL(inode_get_bytes);
463
464void inode_set_bytes(struct inode *inode, loff_t bytes)
465{
466 /* Caller is here responsible for sufficient locking
467 * (ie. inode->i_lock) */
468 inode->i_blocks = bytes >> 9;
469 inode->i_bytes = bytes & 511;
470}
471
472EXPORT_SYMBOL(inode_set_bytes);