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Commit | Line | Data |
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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 = (1 << inode->i_blkbits); | |
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 | ||
458 | void inode_add_bytes(struct inode *inode, loff_t bytes) | |
459 | { | |
460 | spin_lock(&inode->i_lock); | |
461 | __inode_add_bytes(inode, bytes); | |
462 | spin_unlock(&inode->i_lock); | |
463 | } | |
464 | ||
465 | EXPORT_SYMBOL(inode_add_bytes); | |
466 | ||
467 | void __inode_sub_bytes(struct inode *inode, loff_t bytes) | |
468 | { | |
469 | inode->i_blocks -= bytes >> 9; | |
470 | bytes &= 511; | |
471 | if (inode->i_bytes < bytes) { | |
472 | inode->i_blocks--; | |
473 | inode->i_bytes += 512; | |
474 | } | |
475 | inode->i_bytes -= bytes; | |
476 | } | |
477 | ||
478 | EXPORT_SYMBOL(__inode_sub_bytes); | |
479 | ||
480 | void inode_sub_bytes(struct inode *inode, loff_t bytes) | |
481 | { | |
482 | spin_lock(&inode->i_lock); | |
483 | __inode_sub_bytes(inode, bytes); | |
484 | spin_unlock(&inode->i_lock); | |
485 | } | |
486 | ||
487 | EXPORT_SYMBOL(inode_sub_bytes); | |
488 | ||
489 | loff_t inode_get_bytes(struct inode *inode) | |
490 | { | |
491 | loff_t ret; | |
492 | ||
493 | spin_lock(&inode->i_lock); | |
494 | ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; | |
495 | spin_unlock(&inode->i_lock); | |
496 | return ret; | |
497 | } | |
498 | ||
499 | EXPORT_SYMBOL(inode_get_bytes); | |
500 | ||
501 | void inode_set_bytes(struct inode *inode, loff_t bytes) | |
502 | { | |
503 | /* Caller is here responsible for sufficient locking | |
504 | * (ie. inode->i_lock) */ | |
505 | inode->i_blocks = bytes >> 9; | |
506 | inode->i_bytes = bytes & 511; | |
507 | } | |
508 | ||
509 | EXPORT_SYMBOL(inode_set_bytes); |