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