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_stat_fd(int dfd, char __user *name, struct kstat *stat)
59 {
60 struct nameidata nd;
61 int error;
62
63 error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd);
64 if (!error) {
65 error = vfs_getattr(nd.path.mnt, nd.path.dentry, stat);
66 path_put(&nd.path);
67 }
68 return error;
69 }
70
71 int vfs_stat(char __user *name, struct kstat *stat)
72 {
73 return vfs_stat_fd(AT_FDCWD, name, stat);
74 }
75
76 EXPORT_SYMBOL(vfs_stat);
77
78 int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat)
79 {
80 struct nameidata nd;
81 int error;
82
83 error = __user_walk_fd(dfd, name, 0, &nd);
84 if (!error) {
85 error = vfs_getattr(nd.path.mnt, nd.path.dentry, stat);
86 path_put(&nd.path);
87 }
88 return error;
89 }
90
91 int vfs_lstat(char __user *name, struct kstat *stat)
92 {
93 return vfs_lstat_fd(AT_FDCWD, name, stat);
94 }
95
96 EXPORT_SYMBOL(vfs_lstat);
97
98 int vfs_fstat(unsigned int fd, struct kstat *stat)
99 {
100 struct file *f = fget(fd);
101 int error = -EBADF;
102
103 if (f) {
104 error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);
105 fput(f);
106 }
107 return error;
108 }
109
110 EXPORT_SYMBOL(vfs_fstat);
111
112 #ifdef __ARCH_WANT_OLD_STAT
113
114 /*
115 * For backward compatibility? Maybe this should be moved
116 * into arch/i386 instead?
117 */
118 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
119 {
120 static int warncount = 5;
121 struct __old_kernel_stat tmp;
122
123 if (warncount > 0) {
124 warncount--;
125 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
126 current->comm);
127 } else if (warncount < 0) {
128 /* it's laughable, but... */
129 warncount = 0;
130 }
131
132 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
133 tmp.st_dev = old_encode_dev(stat->dev);
134 tmp.st_ino = stat->ino;
135 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
136 return -EOVERFLOW;
137 tmp.st_mode = stat->mode;
138 tmp.st_nlink = stat->nlink;
139 if (tmp.st_nlink != stat->nlink)
140 return -EOVERFLOW;
141 SET_UID(tmp.st_uid, stat->uid);
142 SET_GID(tmp.st_gid, stat->gid);
143 tmp.st_rdev = old_encode_dev(stat->rdev);
144 #if BITS_PER_LONG == 32
145 if (stat->size > MAX_NON_LFS)
146 return -EOVERFLOW;
147 #endif
148 tmp.st_size = stat->size;
149 tmp.st_atime = stat->atime.tv_sec;
150 tmp.st_mtime = stat->mtime.tv_sec;
151 tmp.st_ctime = stat->ctime.tv_sec;
152 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
153 }
154
155 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf)
156 {
157 struct kstat stat;
158 int error = vfs_stat_fd(AT_FDCWD, filename, &stat);
159
160 if (!error)
161 error = cp_old_stat(&stat, statbuf);
162
163 return error;
164 }
165 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf)
166 {
167 struct kstat stat;
168 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat);
169
170 if (!error)
171 error = cp_old_stat(&stat, statbuf);
172
173 return error;
174 }
175 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf)
176 {
177 struct kstat stat;
178 int error = vfs_fstat(fd, &stat);
179
180 if (!error)
181 error = cp_old_stat(&stat, statbuf);
182
183 return error;
184 }
185
186 #endif /* __ARCH_WANT_OLD_STAT */
187
188 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
189 {
190 struct stat tmp;
191
192 #if BITS_PER_LONG == 32
193 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
194 return -EOVERFLOW;
195 #else
196 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
197 return -EOVERFLOW;
198 #endif
199
200 memset(&tmp, 0, sizeof(tmp));
201 #if BITS_PER_LONG == 32
202 tmp.st_dev = old_encode_dev(stat->dev);
203 #else
204 tmp.st_dev = new_encode_dev(stat->dev);
205 #endif
206 tmp.st_ino = stat->ino;
207 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
208 return -EOVERFLOW;
209 tmp.st_mode = stat->mode;
210 tmp.st_nlink = stat->nlink;
211 if (tmp.st_nlink != stat->nlink)
212 return -EOVERFLOW;
213 SET_UID(tmp.st_uid, stat->uid);
214 SET_GID(tmp.st_gid, stat->gid);
215 #if BITS_PER_LONG == 32
216 tmp.st_rdev = old_encode_dev(stat->rdev);
217 #else
218 tmp.st_rdev = new_encode_dev(stat->rdev);
219 #endif
220 #if BITS_PER_LONG == 32
221 if (stat->size > MAX_NON_LFS)
222 return -EOVERFLOW;
223 #endif
224 tmp.st_size = stat->size;
225 tmp.st_atime = stat->atime.tv_sec;
226 tmp.st_mtime = stat->mtime.tv_sec;
227 tmp.st_ctime = stat->ctime.tv_sec;
228 #ifdef STAT_HAVE_NSEC
229 tmp.st_atime_nsec = stat->atime.tv_nsec;
230 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
231 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
232 #endif
233 tmp.st_blocks = stat->blocks;
234 tmp.st_blksize = stat->blksize;
235 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
236 }
237
238 asmlinkage long sys_newstat(char __user *filename, struct stat __user *statbuf)
239 {
240 struct kstat stat;
241 int error = vfs_stat_fd(AT_FDCWD, filename, &stat);
242
243 if (!error)
244 error = cp_new_stat(&stat, statbuf);
245
246 return error;
247 }
248
249 asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf)
250 {
251 struct kstat stat;
252 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat);
253
254 if (!error)
255 error = cp_new_stat(&stat, statbuf);
256
257 return error;
258 }
259
260 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
261 asmlinkage long sys_newfstatat(int dfd, char __user *filename,
262 struct stat __user *statbuf, int flag)
263 {
264 struct kstat stat;
265 int error = -EINVAL;
266
267 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
268 goto out;
269
270 if (flag & AT_SYMLINK_NOFOLLOW)
271 error = vfs_lstat_fd(dfd, filename, &stat);
272 else
273 error = vfs_stat_fd(dfd, filename, &stat);
274
275 if (!error)
276 error = cp_new_stat(&stat, statbuf);
277
278 out:
279 return error;
280 }
281 #endif
282
283 asmlinkage long sys_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
294 asmlinkage long sys_readlinkat(int dfd, const char __user *path,
295 char __user *buf, int bufsiz)
296 {
297 struct nameidata nd;
298 int error;
299
300 if (bufsiz <= 0)
301 return -EINVAL;
302
303 error = __user_walk_fd(dfd, path, 0, &nd);
304 if (!error) {
305 struct inode *inode = nd.path.dentry->d_inode;
306
307 error = -EINVAL;
308 if (inode->i_op && inode->i_op->readlink) {
309 error = security_inode_readlink(nd.path.dentry);
310 if (!error) {
311 touch_atime(nd.path.mnt, nd.path.dentry);
312 error = inode->i_op->readlink(nd.path.dentry,
313 buf, bufsiz);
314 }
315 }
316 path_put(&nd.path);
317 }
318 return error;
319 }
320
321 asmlinkage long sys_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
331 static 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
368 asmlinkage long sys_stat64(char __user * filename, 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 asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf)
379 {
380 struct kstat stat;
381 int error = vfs_lstat(filename, &stat);
382
383 if (!error)
384 error = cp_new_stat64(&stat, statbuf);
385
386 return error;
387 }
388 asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf)
389 {
390 struct kstat stat;
391 int error = vfs_fstat(fd, &stat);
392
393 if (!error)
394 error = cp_new_stat64(&stat, statbuf);
395
396 return error;
397 }
398
399 asmlinkage long sys_fstatat64(int dfd, char __user *filename,
400 struct stat64 __user *statbuf, int flag)
401 {
402 struct kstat stat;
403 int error = -EINVAL;
404
405 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
406 goto out;
407
408 if (flag & AT_SYMLINK_NOFOLLOW)
409 error = vfs_lstat_fd(dfd, filename, &stat);
410 else
411 error = vfs_stat_fd(dfd, filename, &stat);
412
413 if (!error)
414 error = cp_new_stat64(&stat, statbuf);
415
416 out:
417 return error;
418 }
419 #endif /* __ARCH_WANT_STAT64 */
420
421 void inode_add_bytes(struct inode *inode, loff_t bytes)
422 {
423 spin_lock(&inode->i_lock);
424 inode->i_blocks += bytes >> 9;
425 bytes &= 511;
426 inode->i_bytes += bytes;
427 if (inode->i_bytes >= 512) {
428 inode->i_blocks++;
429 inode->i_bytes -= 512;
430 }
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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