1 /*
2 * linux/fs/stat.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/config.h>
8 #include <linux/module.h>
9 #include <linux/mm.h>
10 #include <linux/errno.h>
11 #include <linux/file.h>
12 #include <linux/smp_lock.h>
13 #include <linux/highuid.h>
14 #include <linux/fs.h>
15 #include <linux/namei.h>
16 #include <linux/security.h>
17 #include <linux/syscalls.h>
18
19 #include <asm/uaccess.h>
20 #include <asm/unistd.h>
21
22 void generic_fillattr(struct inode *inode, struct kstat *stat)
23 {
24 stat->dev = inode->i_sb->s_dev;
25 stat->ino = inode->i_ino;
26 stat->mode = inode->i_mode;
27 stat->nlink = inode->i_nlink;
28 stat->uid = inode->i_uid;
29 stat->gid = inode->i_gid;
30 stat->rdev = inode->i_rdev;
31 stat->atime = inode->i_atime;
32 stat->mtime = inode->i_mtime;
33 stat->ctime = inode->i_ctime;
34 stat->size = i_size_read(inode);
35 stat->blocks = inode->i_blocks;
36 stat->blksize = inode->i_blksize;
37 }
38
39 EXPORT_SYMBOL(generic_fillattr);
40
41 int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
42 {
43 struct inode *inode = dentry->d_inode;
44 int retval;
45
46 retval = security_inode_getattr(mnt, dentry);
47 if (retval)
48 return retval;
49
50 if (inode->i_op->getattr)
51 return inode->i_op->getattr(mnt, dentry, stat);
52
53 generic_fillattr(inode, stat);
54 if (!stat->blksize) {
55 struct super_block *s = inode->i_sb;
56 unsigned blocks;
57 blocks = (stat->size+s->s_blocksize-1) >> s->s_blocksize_bits;
58 stat->blocks = (s->s_blocksize / 512) * blocks;
59 stat->blksize = s->s_blocksize;
60 }
61 return 0;
62 }
63
64 EXPORT_SYMBOL(vfs_getattr);
65
66 int vfs_stat(char __user *name, struct kstat *stat)
67 {
68 struct nameidata nd;
69 int error;
70
71 error = user_path_walk(name, &nd);
72 if (!error) {
73 error = vfs_getattr(nd.mnt, nd.dentry, stat);
74 path_release(&nd);
75 }
76 return error;
77 }
78
79 EXPORT_SYMBOL(vfs_stat);
80
81 int vfs_lstat(char __user *name, struct kstat *stat)
82 {
83 struct nameidata nd;
84 int error;
85
86 error = user_path_walk_link(name, &nd);
87 if (!error) {
88 error = vfs_getattr(nd.mnt, nd.dentry, stat);
89 path_release(&nd);
90 }
91 return error;
92 }
93
94 EXPORT_SYMBOL(vfs_lstat);
95
96 int vfs_fstat(unsigned int fd, struct kstat *stat)
97 {
98 struct file *f = fget(fd);
99 int error = -EBADF;
100
101 if (f) {
102 error = vfs_getattr(f->f_vfsmnt, f->f_dentry, stat);
103 fput(f);
104 }
105 return error;
106 }
107
108 EXPORT_SYMBOL(vfs_fstat);
109
110 #ifdef __ARCH_WANT_OLD_STAT
111
112 /*
113 * For backward compatibility? Maybe this should be moved
114 * into arch/i386 instead?
115 */
116 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
117 {
118 static int warncount = 5;
119 struct __old_kernel_stat tmp;
120
121 if (warncount > 0) {
122 warncount--;
123 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
124 current->comm);
125 } else if (warncount < 0) {
126 /* it's laughable, but... */
127 warncount = 0;
128 }
129
130 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
131 tmp.st_dev = old_encode_dev(stat->dev);
132 tmp.st_ino = stat->ino;
133 tmp.st_mode = stat->mode;
134 tmp.st_nlink = stat->nlink;
135 if (tmp.st_nlink != stat->nlink)
136 return -EOVERFLOW;
137 SET_UID(tmp.st_uid, stat->uid);
138 SET_GID(tmp.st_gid, stat->gid);
139 tmp.st_rdev = old_encode_dev(stat->rdev);
140 #if BITS_PER_LONG == 32
141 if (stat->size > MAX_NON_LFS)
142 return -EOVERFLOW;
143 #endif
144 tmp.st_size = stat->size;
145 tmp.st_atime = stat->atime.tv_sec;
146 tmp.st_mtime = stat->mtime.tv_sec;
147 tmp.st_ctime = stat->ctime.tv_sec;
148 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
149 }
150
151 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf)
152 {
153 struct kstat stat;
154 int error = vfs_stat(filename, &stat);
155
156 if (!error)
157 error = cp_old_stat(&stat, statbuf);
158
159 return error;
160 }
161 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf)
162 {
163 struct kstat stat;
164 int error = vfs_lstat(filename, &stat);
165
166 if (!error)
167 error = cp_old_stat(&stat, statbuf);
168
169 return error;
170 }
171 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf)
172 {
173 struct kstat stat;
174 int error = vfs_fstat(fd, &stat);
175
176 if (!error)
177 error = cp_old_stat(&stat, statbuf);
178
179 return error;
180 }
181
182 #endif /* __ARCH_WANT_OLD_STAT */
183
184 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
185 {
186 struct stat tmp;
187
188 #if BITS_PER_LONG == 32
189 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
190 return -EOVERFLOW;
191 #else
192 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
193 return -EOVERFLOW;
194 #endif
195
196 memset(&tmp, 0, sizeof(tmp));
197 #if BITS_PER_LONG == 32
198 tmp.st_dev = old_encode_dev(stat->dev);
199 #else
200 tmp.st_dev = new_encode_dev(stat->dev);
201 #endif
202 tmp.st_ino = stat->ino;
203 tmp.st_mode = stat->mode;
204 tmp.st_nlink = stat->nlink;
205 if (tmp.st_nlink != stat->nlink)
206 return -EOVERFLOW;
207 SET_UID(tmp.st_uid, stat->uid);
208 SET_GID(tmp.st_gid, stat->gid);
209 #if BITS_PER_LONG == 32
210 tmp.st_rdev = old_encode_dev(stat->rdev);
211 #else
212 tmp.st_rdev = new_encode_dev(stat->rdev);
213 #endif
214 #if BITS_PER_LONG == 32
215 if (stat->size > MAX_NON_LFS)
216 return -EOVERFLOW;
217 #endif
218 tmp.st_size = stat->size;
219 tmp.st_atime = stat->atime.tv_sec;
220 tmp.st_mtime = stat->mtime.tv_sec;
221 tmp.st_ctime = stat->ctime.tv_sec;
222 #ifdef STAT_HAVE_NSEC
223 tmp.st_atime_nsec = stat->atime.tv_nsec;
224 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
225 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
226 #endif
227 tmp.st_blocks = stat->blocks;
228 tmp.st_blksize = stat->blksize;
229 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
230 }
231
232 asmlinkage long sys_newstat(char __user * filename, struct stat __user * statbuf)
233 {
234 struct kstat stat;
235 int error = vfs_stat(filename, &stat);
236
237 if (!error)
238 error = cp_new_stat(&stat, statbuf);
239
240 return error;
241 }
242 asmlinkage long sys_newlstat(char __user * filename, struct stat __user * statbuf)
243 {
244 struct kstat stat;
245 int error = vfs_lstat(filename, &stat);
246
247 if (!error)
248 error = cp_new_stat(&stat, statbuf);
249
250 return error;
251 }
252 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user * statbuf)
253 {
254 struct kstat stat;
255 int error = vfs_fstat(fd, &stat);
256
257 if (!error)
258 error = cp_new_stat(&stat, statbuf);
259
260 return error;
261 }
262
263 asmlinkage long sys_readlink(const char __user * path, char __user * buf, int bufsiz)
264 {
265 struct nameidata nd;
266 int error;
267
268 if (bufsiz <= 0)
269 return -EINVAL;
270
271 error = user_path_walk_link(path, &nd);
272 if (!error) {
273 struct inode * inode = nd.dentry->d_inode;
274
275 error = -EINVAL;
276 if (inode->i_op && inode->i_op->readlink) {
277 error = security_inode_readlink(nd.dentry);
278 if (!error) {
279 touch_atime(nd.mnt, nd.dentry);
280 error = inode->i_op->readlink(nd.dentry, buf, bufsiz);
281 }
282 }
283 path_release(&nd);
284 }
285 return error;
286 }
287
288
289 /* ---------- LFS-64 ----------- */
290 #ifdef __ARCH_WANT_STAT64
291
292 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
293 {
294 struct stat64 tmp;
295
296 memset(&tmp, 0, sizeof(struct stat64));
297 #ifdef CONFIG_MIPS
298 /* mips has weird padding, so we don't get 64 bits there */
299 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
300 return -EOVERFLOW;
301 tmp.st_dev = new_encode_dev(stat->dev);
302 tmp.st_rdev = new_encode_dev(stat->rdev);
303 #else
304 tmp.st_dev = huge_encode_dev(stat->dev);
305 tmp.st_rdev = huge_encode_dev(stat->rdev);
306 #endif
307 tmp.st_ino = stat->ino;
308 #ifdef STAT64_HAS_BROKEN_ST_INO
309 tmp.__st_ino = stat->ino;
310 #endif
311 tmp.st_mode = stat->mode;
312 tmp.st_nlink = stat->nlink;
313 tmp.st_uid = stat->uid;
314 tmp.st_gid = stat->gid;
315 tmp.st_atime = stat->atime.tv_sec;
316 tmp.st_atime_nsec = stat->atime.tv_nsec;
317 tmp.st_mtime = stat->mtime.tv_sec;
318 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
319 tmp.st_ctime = stat->ctime.tv_sec;
320 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
321 tmp.st_size = stat->size;
322 tmp.st_blocks = stat->blocks;
323 tmp.st_blksize = stat->blksize;
324 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
325 }
326
327 asmlinkage long sys_stat64(char __user * filename, struct stat64 __user * statbuf)
328 {
329 struct kstat stat;
330 int error = vfs_stat(filename, &stat);
331
332 if (!error)
333 error = cp_new_stat64(&stat, statbuf);
334
335 return error;
336 }
337 asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf)
338 {
339 struct kstat stat;
340 int error = vfs_lstat(filename, &stat);
341
342 if (!error)
343 error = cp_new_stat64(&stat, statbuf);
344
345 return error;
346 }
347 asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf)
348 {
349 struct kstat stat;
350 int error = vfs_fstat(fd, &stat);
351
352 if (!error)
353 error = cp_new_stat64(&stat, statbuf);
354
355 return error;
356 }
357
358 #endif /* __ARCH_WANT_STAT64 */
359
360 void inode_add_bytes(struct inode *inode, loff_t bytes)
361 {
362 spin_lock(&inode->i_lock);
363 inode->i_blocks += bytes >> 9;
364 bytes &= 511;
365 inode->i_bytes += bytes;
366 if (inode->i_bytes >= 512) {
367 inode->i_blocks++;
368 inode->i_bytes -= 512;
369 }
370 spin_unlock(&inode->i_lock);
371 }
372
373 EXPORT_SYMBOL(inode_add_bytes);
374
375 void inode_sub_bytes(struct inode *inode, loff_t bytes)
376 {
377 spin_lock(&inode->i_lock);
378 inode->i_blocks -= bytes >> 9;
379 bytes &= 511;
380 if (inode->i_bytes < bytes) {
381 inode->i_blocks--;
382 inode->i_bytes += 512;
383 }
384 inode->i_bytes -= bytes;
385 spin_unlock(&inode->i_lock);
386 }
387
388 EXPORT_SYMBOL(inode_sub_bytes);
389
390 loff_t inode_get_bytes(struct inode *inode)
391 {
392 loff_t ret;
393
394 spin_lock(&inode->i_lock);
395 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
396 spin_unlock(&inode->i_lock);
397 return ret;
398 }
399
400 EXPORT_SYMBOL(inode_get_bytes);
401
402 void inode_set_bytes(struct inode *inode, loff_t bytes)
403 {
404 /* Caller is here responsible for sufficient locking
405 * (ie. inode->i_lock) */
406 inode->i_blocks = bytes >> 9;
407 inode->i_bytes = bytes & 511;
408 }
409
410 EXPORT_SYMBOL(inode_set_bytes);
411
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