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