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
generic_fillattr(struct inode * inode,struct kstat * stat)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
vfs_getattr(struct vfsmount * mnt,struct dentry * dentry,struct kstat * stat)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
vfs_fstat(unsigned int fd,struct kstat * stat)58 int vfs_fstat(unsigned int fd, struct kstat *stat)
59 {
60 int fput_needed;
61 struct file *f = fget_light(fd, &fput_needed);
62 int error = -EBADF;
63
64 if (f) {
65 error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);
66 fput_light(f, fput_needed);
67 }
68 return error;
69 }
70 EXPORT_SYMBOL(vfs_fstat);
71
vfs_fstatat(int dfd,const char __user * filename,struct kstat * stat,int flag)72 int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
73 int flag)
74 {
75 struct path path;
76 int error = -EINVAL;
77 int lookup_flags = 0;
78
79 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
80 AT_EMPTY_PATH)) != 0)
81 goto out;
82
83 if (!(flag & AT_SYMLINK_NOFOLLOW))
84 lookup_flags |= LOOKUP_FOLLOW;
85 if (flag & AT_EMPTY_PATH)
86 lookup_flags |= LOOKUP_EMPTY;
87
88 error = user_path_at(dfd, filename, lookup_flags, &path);
89 if (error)
90 goto out;
91
92 error = vfs_getattr(path.mnt, path.dentry, stat);
93 path_put(&path);
94 out:
95 return error;
96 }
97 EXPORT_SYMBOL(vfs_fstatat);
98
vfs_stat(const char __user * name,struct kstat * stat)99 int vfs_stat(const char __user *name, struct kstat *stat)
100 {
101 return vfs_fstatat(AT_FDCWD, name, stat, 0);
102 }
103 EXPORT_SYMBOL(vfs_stat);
104
vfs_lstat(const char __user * name,struct kstat * stat)105 int vfs_lstat(const char __user *name, struct kstat *stat)
106 {
107 return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
108 }
109 EXPORT_SYMBOL(vfs_lstat);
110
111
112 #ifdef __ARCH_WANT_OLD_STAT
113
114 /*
115 * For backward compatibility? Maybe this should be moved
116 * into arch/i386 instead?
117 */
cp_old_stat(struct kstat * stat,struct __old_kernel_stat __user * statbuf)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
SYSCALL_DEFINE2(stat,const char __user *,filename,struct __old_kernel_stat __user *,statbuf)155 SYSCALL_DEFINE2(stat, const char __user *, filename,
156 struct __old_kernel_stat __user *, statbuf)
157 {
158 struct kstat stat;
159 int error;
160
161 error = vfs_stat(filename, &stat);
162 if (error)
163 return error;
164
165 return cp_old_stat(&stat, statbuf);
166 }
167
SYSCALL_DEFINE2(lstat,const char __user *,filename,struct __old_kernel_stat __user *,statbuf)168 SYSCALL_DEFINE2(lstat, const char __user *, filename,
169 struct __old_kernel_stat __user *, statbuf)
170 {
171 struct kstat stat;
172 int error;
173
174 error = vfs_lstat(filename, &stat);
175 if (error)
176 return error;
177
178 return cp_old_stat(&stat, statbuf);
179 }
180
SYSCALL_DEFINE2(fstat,unsigned int,fd,struct __old_kernel_stat __user *,statbuf)181 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
182 {
183 struct kstat stat;
184 int error = vfs_fstat(fd, &stat);
185
186 if (!error)
187 error = cp_old_stat(&stat, statbuf);
188
189 return error;
190 }
191
192 #endif /* __ARCH_WANT_OLD_STAT */
193
cp_new_stat(struct kstat * stat,struct stat __user * statbuf)194 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
195 {
196 struct stat tmp;
197
198 #if BITS_PER_LONG == 32
199 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
200 return -EOVERFLOW;
201 #else
202 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
203 return -EOVERFLOW;
204 #endif
205
206 memset(&tmp, 0, sizeof(tmp));
207 #if BITS_PER_LONG == 32
208 tmp.st_dev = old_encode_dev(stat->dev);
209 #else
210 tmp.st_dev = new_encode_dev(stat->dev);
211 #endif
212 tmp.st_ino = stat->ino;
213 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
214 return -EOVERFLOW;
215 tmp.st_mode = stat->mode;
216 tmp.st_nlink = stat->nlink;
217 if (tmp.st_nlink != stat->nlink)
218 return -EOVERFLOW;
219 SET_UID(tmp.st_uid, stat->uid);
220 SET_GID(tmp.st_gid, stat->gid);
221 #if BITS_PER_LONG == 32
222 tmp.st_rdev = old_encode_dev(stat->rdev);
223 #else
224 tmp.st_rdev = new_encode_dev(stat->rdev);
225 #endif
226 #if BITS_PER_LONG == 32
227 if (stat->size > MAX_NON_LFS)
228 return -EOVERFLOW;
229 #endif
230 tmp.st_size = stat->size;
231 tmp.st_atime = stat->atime.tv_sec;
232 tmp.st_mtime = stat->mtime.tv_sec;
233 tmp.st_ctime = stat->ctime.tv_sec;
234 #ifdef STAT_HAVE_NSEC
235 tmp.st_atime_nsec = stat->atime.tv_nsec;
236 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
237 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
238 #endif
239 tmp.st_blocks = stat->blocks;
240 tmp.st_blksize = stat->blksize;
241 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
242 }
243
SYSCALL_DEFINE2(newstat,const char __user *,filename,struct stat __user *,statbuf)244 SYSCALL_DEFINE2(newstat, const char __user *, filename,
245 struct stat __user *, statbuf)
246 {
247 struct kstat stat;
248 int error = vfs_stat(filename, &stat);
249
250 if (error)
251 return error;
252 return cp_new_stat(&stat, statbuf);
253 }
254
SYSCALL_DEFINE2(newlstat,const char __user *,filename,struct stat __user *,statbuf)255 SYSCALL_DEFINE2(newlstat, const char __user *, filename,
256 struct stat __user *, statbuf)
257 {
258 struct kstat stat;
259 int error;
260
261 error = vfs_lstat(filename, &stat);
262 if (error)
263 return error;
264
265 return cp_new_stat(&stat, statbuf);
266 }
267
268 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
SYSCALL_DEFINE4(newfstatat,int,dfd,const char __user *,filename,struct stat __user *,statbuf,int,flag)269 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
270 struct stat __user *, statbuf, int, flag)
271 {
272 struct kstat stat;
273 int error;
274
275 error = vfs_fstatat(dfd, filename, &stat, flag);
276 if (error)
277 return error;
278 return cp_new_stat(&stat, statbuf);
279 }
280 #endif
281
SYSCALL_DEFINE2(newfstat,unsigned int,fd,struct stat __user *,statbuf)282 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
283 {
284 struct kstat stat;
285 int error = vfs_fstat(fd, &stat);
286
287 if (!error)
288 error = cp_new_stat(&stat, statbuf);
289
290 return error;
291 }
292
SYSCALL_DEFINE4(readlinkat,int,dfd,const char __user *,pathname,char __user *,buf,int,bufsiz)293 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
294 char __user *, buf, int, bufsiz)
295 {
296 struct path path;
297 int error;
298 int empty = 0;
299
300 if (bufsiz <= 0)
301 return -EINVAL;
302
303 error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);
304 if (!error) {
305 struct inode *inode = path.dentry->d_inode;
306
307 error = empty ? -ENOENT : -EINVAL;
308 if (inode->i_op->readlink) {
309 error = security_inode_readlink(path.dentry);
310 if (!error) {
311 touch_atime(&path);
312 error = inode->i_op->readlink(path.dentry,
313 buf, bufsiz);
314 }
315 }
316 path_put(&path);
317 }
318 return error;
319 }
320
SYSCALL_DEFINE3(readlink,const char __user *,path,char __user *,buf,int,bufsiz)321 SYSCALL_DEFINE3(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
cp_new_stat64(struct kstat * stat,struct stat64 __user * statbuf)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
SYSCALL_DEFINE2(stat64,const char __user *,filename,struct stat64 __user *,statbuf)368 SYSCALL_DEFINE2(stat64, const char __user *, filename,
369 struct stat64 __user *, statbuf)
370 {
371 struct kstat stat;
372 int error = vfs_stat(filename, &stat);
373
374 if (!error)
375 error = cp_new_stat64(&stat, statbuf);
376
377 return error;
378 }
379
SYSCALL_DEFINE2(lstat64,const char __user *,filename,struct stat64 __user *,statbuf)380 SYSCALL_DEFINE2(lstat64, const char __user *, filename,
381 struct stat64 __user *, statbuf)
382 {
383 struct kstat stat;
384 int error = vfs_lstat(filename, &stat);
385
386 if (!error)
387 error = cp_new_stat64(&stat, statbuf);
388
389 return error;
390 }
391
SYSCALL_DEFINE2(fstat64,unsigned long,fd,struct stat64 __user *,statbuf)392 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
393 {
394 struct kstat stat;
395 int error = vfs_fstat(fd, &stat);
396
397 if (!error)
398 error = cp_new_stat64(&stat, statbuf);
399
400 return error;
401 }
402
SYSCALL_DEFINE4(fstatat64,int,dfd,const char __user *,filename,struct stat64 __user *,statbuf,int,flag)403 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
404 struct stat64 __user *, statbuf, int, flag)
405 {
406 struct kstat stat;
407 int error;
408
409 error = vfs_fstatat(dfd, filename, &stat, flag);
410 if (error)
411 return error;
412 return cp_new_stat64(&stat, statbuf);
413 }
414 #endif /* __ARCH_WANT_STAT64 */
415
416 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
__inode_add_bytes(struct inode * inode,loff_t bytes)417 void __inode_add_bytes(struct inode *inode, loff_t bytes)
418 {
419 inode->i_blocks += bytes >> 9;
420 bytes &= 511;
421 inode->i_bytes += bytes;
422 if (inode->i_bytes >= 512) {
423 inode->i_blocks++;
424 inode->i_bytes -= 512;
425 }
426 }
427
inode_add_bytes(struct inode * inode,loff_t bytes)428 void inode_add_bytes(struct inode *inode, loff_t bytes)
429 {
430 spin_lock(&inode->i_lock);
431 __inode_add_bytes(inode, bytes);
432 spin_unlock(&inode->i_lock);
433 }
434
435 EXPORT_SYMBOL(inode_add_bytes);
436
inode_sub_bytes(struct inode * inode,loff_t bytes)437 void inode_sub_bytes(struct inode *inode, loff_t bytes)
438 {
439 spin_lock(&inode->i_lock);
440 inode->i_blocks -= bytes >> 9;
441 bytes &= 511;
442 if (inode->i_bytes < bytes) {
443 inode->i_blocks--;
444 inode->i_bytes += 512;
445 }
446 inode->i_bytes -= bytes;
447 spin_unlock(&inode->i_lock);
448 }
449
450 EXPORT_SYMBOL(inode_sub_bytes);
451
inode_get_bytes(struct inode * inode)452 loff_t inode_get_bytes(struct inode *inode)
453 {
454 loff_t ret;
455
456 spin_lock(&inode->i_lock);
457 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
458 spin_unlock(&inode->i_lock);
459 return ret;
460 }
461
462 EXPORT_SYMBOL(inode_get_bytes);
463
inode_set_bytes(struct inode * inode,loff_t bytes)464 void inode_set_bytes(struct inode *inode, loff_t bytes)
465 {
466 /* Caller is here responsible for sufficient locking
467 * (ie. inode->i_lock) */
468 inode->i_blocks = bytes >> 9;
469 inode->i_bytes = bytes & 511;
470 }
471
472 EXPORT_SYMBOL(inode_set_bytes);
473