blob: 068fdbcc9e26a990ed102b961408ced5ba852b24
1 | /* |
2 | * linux/fs/stat.c |
3 | * |
4 | * Copyright (C) 1991, 1992 Linus Torvalds |
5 | */ |
6 | |
7 | #include <linux/export.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 | |
21 | void 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->size = i_size_read(inode); |
31 | stat->atime = inode->i_atime; |
32 | stat->mtime = inode->i_mtime; |
33 | stat->ctime = inode->i_ctime; |
34 | stat->blksize = i_blocksize(inode); |
35 | stat->blocks = inode->i_blocks; |
36 | } |
37 | |
38 | EXPORT_SYMBOL(generic_fillattr); |
39 | |
40 | /** |
41 | * vfs_getattr_nosec - getattr without security checks |
42 | * @path: file to get attributes from |
43 | * @stat: structure to return attributes in |
44 | * |
45 | * Get attributes without calling security_inode_getattr. |
46 | * |
47 | * Currently the only caller other than vfs_getattr is internal to the |
48 | * filehandle lookup code, which uses only the inode number and returns |
49 | * no attributes to any user. Any other code probably wants |
50 | * vfs_getattr. |
51 | */ |
52 | int vfs_getattr_nosec(struct path *path, struct kstat *stat) |
53 | { |
54 | struct inode *inode = d_backing_inode(path->dentry); |
55 | |
56 | if (inode->i_op->getattr) |
57 | return inode->i_op->getattr(path->mnt, path->dentry, stat); |
58 | |
59 | generic_fillattr(inode, stat); |
60 | return 0; |
61 | } |
62 | |
63 | EXPORT_SYMBOL(vfs_getattr_nosec); |
64 | |
65 | int vfs_getattr(struct path *path, struct kstat *stat) |
66 | { |
67 | int retval; |
68 | |
69 | retval = security_inode_getattr(path); |
70 | if (retval) |
71 | return retval; |
72 | return vfs_getattr_nosec(path, stat); |
73 | } |
74 | |
75 | EXPORT_SYMBOL(vfs_getattr); |
76 | |
77 | int vfs_fstat(unsigned int fd, struct kstat *stat) |
78 | { |
79 | struct fd f = fdget_raw(fd); |
80 | int error = -EBADF; |
81 | |
82 | if (f.file) { |
83 | error = vfs_getattr(&f.file->f_path, stat); |
84 | fdput(f); |
85 | } |
86 | return error; |
87 | } |
88 | EXPORT_SYMBOL(vfs_fstat); |
89 | |
90 | int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat, |
91 | int flag) |
92 | { |
93 | struct path path; |
94 | int error = -EINVAL; |
95 | unsigned int lookup_flags = 0; |
96 | |
97 | if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | |
98 | AT_EMPTY_PATH)) != 0) |
99 | goto out; |
100 | |
101 | if (!(flag & AT_SYMLINK_NOFOLLOW)) |
102 | lookup_flags |= LOOKUP_FOLLOW; |
103 | if (flag & AT_EMPTY_PATH) |
104 | lookup_flags |= LOOKUP_EMPTY; |
105 | retry: |
106 | error = user_path_at(dfd, filename, lookup_flags, &path); |
107 | if (error) |
108 | goto out; |
109 | |
110 | error = vfs_getattr(&path, stat); |
111 | path_put(&path); |
112 | if (retry_estale(error, lookup_flags)) { |
113 | lookup_flags |= LOOKUP_REVAL; |
114 | goto retry; |
115 | } |
116 | out: |
117 | return error; |
118 | } |
119 | EXPORT_SYMBOL(vfs_fstatat); |
120 | |
121 | int vfs_stat(const char __user *name, struct kstat *stat) |
122 | { |
123 | return vfs_fstatat(AT_FDCWD, name, stat, 0); |
124 | } |
125 | EXPORT_SYMBOL(vfs_stat); |
126 | |
127 | int vfs_lstat(const char __user *name, struct kstat *stat) |
128 | { |
129 | return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW); |
130 | } |
131 | EXPORT_SYMBOL(vfs_lstat); |
132 | |
133 | |
134 | #ifdef __ARCH_WANT_OLD_STAT |
135 | |
136 | /* |
137 | * For backward compatibility? Maybe this should be moved |
138 | * into arch/i386 instead? |
139 | */ |
140 | static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) |
141 | { |
142 | static int warncount = 5; |
143 | struct __old_kernel_stat tmp; |
144 | |
145 | if (warncount > 0) { |
146 | warncount--; |
147 | printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", |
148 | current->comm); |
149 | } else if (warncount < 0) { |
150 | /* it's laughable, but... */ |
151 | warncount = 0; |
152 | } |
153 | |
154 | memset(&tmp, 0, sizeof(struct __old_kernel_stat)); |
155 | tmp.st_dev = old_encode_dev(stat->dev); |
156 | tmp.st_ino = stat->ino; |
157 | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) |
158 | return -EOVERFLOW; |
159 | tmp.st_mode = stat->mode; |
160 | tmp.st_nlink = stat->nlink; |
161 | if (tmp.st_nlink != stat->nlink) |
162 | return -EOVERFLOW; |
163 | SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); |
164 | SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); |
165 | tmp.st_rdev = old_encode_dev(stat->rdev); |
166 | #if BITS_PER_LONG == 32 |
167 | if (stat->size > MAX_NON_LFS) |
168 | return -EOVERFLOW; |
169 | #endif |
170 | tmp.st_size = stat->size; |
171 | tmp.st_atime = stat->atime.tv_sec; |
172 | tmp.st_mtime = stat->mtime.tv_sec; |
173 | tmp.st_ctime = stat->ctime.tv_sec; |
174 | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; |
175 | } |
176 | |
177 | SYSCALL_DEFINE2(stat, const char __user *, filename, |
178 | struct __old_kernel_stat __user *, statbuf) |
179 | { |
180 | struct kstat stat; |
181 | int error; |
182 | |
183 | error = vfs_stat(filename, &stat); |
184 | if (error) |
185 | return error; |
186 | |
187 | return cp_old_stat(&stat, statbuf); |
188 | } |
189 | |
190 | SYSCALL_DEFINE2(lstat, const char __user *, filename, |
191 | struct __old_kernel_stat __user *, statbuf) |
192 | { |
193 | struct kstat stat; |
194 | int error; |
195 | |
196 | error = vfs_lstat(filename, &stat); |
197 | if (error) |
198 | return error; |
199 | |
200 | return cp_old_stat(&stat, statbuf); |
201 | } |
202 | |
203 | SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf) |
204 | { |
205 | struct kstat stat; |
206 | int error = vfs_fstat(fd, &stat); |
207 | |
208 | if (!error) |
209 | error = cp_old_stat(&stat, statbuf); |
210 | |
211 | return error; |
212 | } |
213 | |
214 | #endif /* __ARCH_WANT_OLD_STAT */ |
215 | |
216 | #if BITS_PER_LONG == 32 |
217 | # define choose_32_64(a,b) a |
218 | #else |
219 | # define choose_32_64(a,b) b |
220 | #endif |
221 | |
222 | #define valid_dev(x) choose_32_64(old_valid_dev(x),true) |
223 | #define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x) |
224 | |
225 | #ifndef INIT_STRUCT_STAT_PADDING |
226 | # define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st)) |
227 | #endif |
228 | |
229 | static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) |
230 | { |
231 | struct stat tmp; |
232 | |
233 | if (!valid_dev(stat->dev) || !valid_dev(stat->rdev)) |
234 | return -EOVERFLOW; |
235 | #if BITS_PER_LONG == 32 |
236 | if (stat->size > MAX_NON_LFS) |
237 | return -EOVERFLOW; |
238 | #endif |
239 | |
240 | INIT_STRUCT_STAT_PADDING(tmp); |
241 | tmp.st_dev = encode_dev(stat->dev); |
242 | tmp.st_ino = stat->ino; |
243 | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) |
244 | return -EOVERFLOW; |
245 | tmp.st_mode = stat->mode; |
246 | tmp.st_nlink = stat->nlink; |
247 | if (tmp.st_nlink != stat->nlink) |
248 | return -EOVERFLOW; |
249 | SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); |
250 | SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); |
251 | tmp.st_rdev = encode_dev(stat->rdev); |
252 | tmp.st_size = stat->size; |
253 | tmp.st_atime = stat->atime.tv_sec; |
254 | tmp.st_mtime = stat->mtime.tv_sec; |
255 | tmp.st_ctime = stat->ctime.tv_sec; |
256 | #ifdef STAT_HAVE_NSEC |
257 | tmp.st_atime_nsec = stat->atime.tv_nsec; |
258 | tmp.st_mtime_nsec = stat->mtime.tv_nsec; |
259 | tmp.st_ctime_nsec = stat->ctime.tv_nsec; |
260 | #endif |
261 | tmp.st_blocks = stat->blocks; |
262 | tmp.st_blksize = stat->blksize; |
263 | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; |
264 | } |
265 | |
266 | SYSCALL_DEFINE2(newstat, const char __user *, filename, |
267 | struct stat __user *, statbuf) |
268 | { |
269 | struct kstat stat; |
270 | int error = vfs_stat(filename, &stat); |
271 | |
272 | if (error) |
273 | return error; |
274 | return cp_new_stat(&stat, statbuf); |
275 | } |
276 | |
277 | SYSCALL_DEFINE2(newlstat, const char __user *, filename, |
278 | struct stat __user *, statbuf) |
279 | { |
280 | struct kstat stat; |
281 | int error; |
282 | |
283 | error = vfs_lstat(filename, &stat); |
284 | if (error) |
285 | return error; |
286 | |
287 | return cp_new_stat(&stat, statbuf); |
288 | } |
289 | |
290 | #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) |
291 | SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename, |
292 | struct stat __user *, statbuf, int, flag) |
293 | { |
294 | struct kstat stat; |
295 | int error; |
296 | |
297 | error = vfs_fstatat(dfd, filename, &stat, flag); |
298 | if (error) |
299 | return error; |
300 | return cp_new_stat(&stat, statbuf); |
301 | } |
302 | #endif |
303 | |
304 | SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf) |
305 | { |
306 | struct kstat stat; |
307 | int error = vfs_fstat(fd, &stat); |
308 | |
309 | if (!error) |
310 | error = cp_new_stat(&stat, statbuf); |
311 | |
312 | return error; |
313 | } |
314 | |
315 | SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, |
316 | char __user *, buf, int, bufsiz) |
317 | { |
318 | struct path path; |
319 | int error; |
320 | int empty = 0; |
321 | unsigned int lookup_flags = LOOKUP_EMPTY; |
322 | |
323 | if (bufsiz <= 0) |
324 | return -EINVAL; |
325 | |
326 | retry: |
327 | error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty); |
328 | if (!error) { |
329 | struct inode *inode = d_backing_inode(path.dentry); |
330 | |
331 | error = empty ? -ENOENT : -EINVAL; |
332 | if (inode->i_op->readlink) { |
333 | error = security_inode_readlink(path.dentry); |
334 | if (!error) { |
335 | touch_atime(&path); |
336 | error = inode->i_op->readlink(path.dentry, |
337 | buf, bufsiz); |
338 | } |
339 | } |
340 | path_put(&path); |
341 | if (retry_estale(error, lookup_flags)) { |
342 | lookup_flags |= LOOKUP_REVAL; |
343 | goto retry; |
344 | } |
345 | } |
346 | return error; |
347 | } |
348 | |
349 | SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf, |
350 | int, bufsiz) |
351 | { |
352 | return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); |
353 | } |
354 | |
355 | |
356 | /* ---------- LFS-64 ----------- */ |
357 | #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64) |
358 | |
359 | #ifndef INIT_STRUCT_STAT64_PADDING |
360 | # define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st)) |
361 | #endif |
362 | |
363 | static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) |
364 | { |
365 | struct stat64 tmp; |
366 | |
367 | INIT_STRUCT_STAT64_PADDING(tmp); |
368 | #ifdef CONFIG_MIPS |
369 | /* mips has weird padding, so we don't get 64 bits there */ |
370 | tmp.st_dev = new_encode_dev(stat->dev); |
371 | tmp.st_rdev = new_encode_dev(stat->rdev); |
372 | #else |
373 | tmp.st_dev = huge_encode_dev(stat->dev); |
374 | tmp.st_rdev = huge_encode_dev(stat->rdev); |
375 | #endif |
376 | tmp.st_ino = stat->ino; |
377 | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) |
378 | return -EOVERFLOW; |
379 | #ifdef STAT64_HAS_BROKEN_ST_INO |
380 | tmp.__st_ino = stat->ino; |
381 | #endif |
382 | tmp.st_mode = stat->mode; |
383 | tmp.st_nlink = stat->nlink; |
384 | tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid); |
385 | tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid); |
386 | tmp.st_atime = stat->atime.tv_sec; |
387 | tmp.st_atime_nsec = stat->atime.tv_nsec; |
388 | tmp.st_mtime = stat->mtime.tv_sec; |
389 | tmp.st_mtime_nsec = stat->mtime.tv_nsec; |
390 | tmp.st_ctime = stat->ctime.tv_sec; |
391 | tmp.st_ctime_nsec = stat->ctime.tv_nsec; |
392 | tmp.st_size = stat->size; |
393 | tmp.st_blocks = stat->blocks; |
394 | tmp.st_blksize = stat->blksize; |
395 | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; |
396 | } |
397 | |
398 | SYSCALL_DEFINE2(stat64, const char __user *, filename, |
399 | struct stat64 __user *, statbuf) |
400 | { |
401 | struct kstat stat; |
402 | int error = vfs_stat(filename, &stat); |
403 | |
404 | if (!error) |
405 | error = cp_new_stat64(&stat, statbuf); |
406 | |
407 | return error; |
408 | } |
409 | |
410 | SYSCALL_DEFINE2(lstat64, const char __user *, filename, |
411 | struct stat64 __user *, statbuf) |
412 | { |
413 | struct kstat stat; |
414 | int error = vfs_lstat(filename, &stat); |
415 | |
416 | if (!error) |
417 | error = cp_new_stat64(&stat, statbuf); |
418 | |
419 | return error; |
420 | } |
421 | |
422 | SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf) |
423 | { |
424 | struct kstat stat; |
425 | int error = vfs_fstat(fd, &stat); |
426 | |
427 | if (!error) |
428 | error = cp_new_stat64(&stat, statbuf); |
429 | |
430 | return error; |
431 | } |
432 | |
433 | SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename, |
434 | struct stat64 __user *, statbuf, int, flag) |
435 | { |
436 | struct kstat stat; |
437 | int error; |
438 | |
439 | error = vfs_fstatat(dfd, filename, &stat, flag); |
440 | if (error) |
441 | return error; |
442 | return cp_new_stat64(&stat, statbuf); |
443 | } |
444 | #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */ |
445 | |
446 | /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */ |
447 | void __inode_add_bytes(struct inode *inode, loff_t bytes) |
448 | { |
449 | inode->i_blocks += bytes >> 9; |
450 | bytes &= 511; |
451 | inode->i_bytes += bytes; |
452 | if (inode->i_bytes >= 512) { |
453 | inode->i_blocks++; |
454 | inode->i_bytes -= 512; |
455 | } |
456 | } |
457 | EXPORT_SYMBOL(__inode_add_bytes); |
458 | |
459 | void inode_add_bytes(struct inode *inode, loff_t bytes) |
460 | { |
461 | spin_lock(&inode->i_lock); |
462 | __inode_add_bytes(inode, bytes); |
463 | spin_unlock(&inode->i_lock); |
464 | } |
465 | |
466 | EXPORT_SYMBOL(inode_add_bytes); |
467 | |
468 | void __inode_sub_bytes(struct inode *inode, loff_t bytes) |
469 | { |
470 | inode->i_blocks -= bytes >> 9; |
471 | bytes &= 511; |
472 | if (inode->i_bytes < bytes) { |
473 | inode->i_blocks--; |
474 | inode->i_bytes += 512; |
475 | } |
476 | inode->i_bytes -= bytes; |
477 | } |
478 | |
479 | EXPORT_SYMBOL(__inode_sub_bytes); |
480 | |
481 | void inode_sub_bytes(struct inode *inode, loff_t bytes) |
482 | { |
483 | spin_lock(&inode->i_lock); |
484 | __inode_sub_bytes(inode, bytes); |
485 | spin_unlock(&inode->i_lock); |
486 | } |
487 | |
488 | EXPORT_SYMBOL(inode_sub_bytes); |
489 | |
490 | loff_t inode_get_bytes(struct inode *inode) |
491 | { |
492 | loff_t ret; |
493 | |
494 | spin_lock(&inode->i_lock); |
495 | ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; |
496 | spin_unlock(&inode->i_lock); |
497 | return ret; |
498 | } |
499 | |
500 | EXPORT_SYMBOL(inode_get_bytes); |
501 | |
502 | void inode_set_bytes(struct inode *inode, loff_t bytes) |
503 | { |
504 | /* Caller is here responsible for sufficient locking |
505 | * (ie. inode->i_lock) */ |
506 | inode->i_blocks = bytes >> 9; |
507 | inode->i_bytes = bytes & 511; |
508 | } |
509 | |
510 | EXPORT_SYMBOL(inode_set_bytes); |
511 |