1 /*
2 * linux/fs/stat.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/mm.h>
8 #include <linux/errno.h>
9 #include <linux/file.h>
10 #include <linux/smp_lock.h>
11 #include <linux/highuid.h>
12
13 #include <asm/uaccess.h>
14
15 /*
16 * Revalidate the inode. This is required for proper NFS attribute caching.
17 */
18 static __inline__ int
19 do_revalidate(struct dentry *dentry)
20 {
21 struct inode * inode = dentry->d_inode;
22 if (inode->i_op && inode->i_op->revalidate)
23 return inode->i_op->revalidate(dentry);
24 return 0;
25 }
26
27
28 #if !defined(__alpha__) && !defined(__sparc__) && !defined(__ia64__) && !defined(__s390__) && !defined(__hppa__)
29
30 /*
31 * For backward compatibility? Maybe this should be moved
32 * into arch/i386 instead?
33 */
34 static int cp_old_stat(struct inode * inode, struct __old_kernel_stat * statbuf)
35 {
36 static int warncount = 5;
37 struct __old_kernel_stat tmp;
38
39 if (warncount > 0) {
40 warncount--;
41 printk("VFS: Warning: %s using old stat() call. Recompile your binary.\n",
42 current->comm);
43 } else if (warncount < 0) {
44 /* it's laughable, but... */
45 warncount = 0;
46 }
47
48 tmp.st_dev = kdev_t_to_nr(inode->i_dev);
49 tmp.st_ino = inode->i_ino;
50 tmp.st_mode = inode->i_mode;
51 tmp.st_nlink = inode->i_nlink;
52 SET_OLDSTAT_UID(tmp, inode->i_uid);
53 SET_OLDSTAT_GID(tmp, inode->i_gid);
54 tmp.st_rdev = kdev_t_to_nr(inode->i_rdev);
55 #if BITS_PER_LONG == 32
56 if (inode->i_size > 0x7fffffff)
57 return -EOVERFLOW;
58 #endif
59 tmp.st_size = inode->i_size;
60 tmp.st_atime = inode->i_atime;
61 tmp.st_mtime = inode->i_mtime;
62 tmp.st_ctime = inode->i_ctime;
63 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
64 }
65
66 #endif
67
68 static int cp_new_stat(struct inode * inode, struct stat * statbuf)
69 {
70 struct stat tmp;
71 unsigned int blocks, indirect;
72
73 memset(&tmp, 0, sizeof(tmp));
74 tmp.st_dev = kdev_t_to_nr(inode->i_dev);
75 tmp.st_ino = inode->i_ino;
76 tmp.st_mode = inode->i_mode;
77 tmp.st_nlink = inode->i_nlink;
78 SET_STAT_UID(tmp, inode->i_uid);
79 SET_STAT_GID(tmp, inode->i_gid);
80 tmp.st_rdev = kdev_t_to_nr(inode->i_rdev);
81 #if BITS_PER_LONG == 32
82 if (inode->i_size > 0x7fffffff)
83 return -EOVERFLOW;
84 #endif
85 tmp.st_size = inode->i_size;
86 tmp.st_atime = inode->i_atime;
87 tmp.st_mtime = inode->i_mtime;
88 tmp.st_ctime = inode->i_ctime;
89 /*
90 * st_blocks and st_blksize are approximated with a simple algorithm if
91 * they aren't supported directly by the filesystem. The minix and msdos
92 * filesystems don't keep track of blocks, so they would either have to
93 * be counted explicitly (by delving into the file itself), or by using
94 * this simple algorithm to get a reasonable (although not 100% accurate)
95 * value.
96 */
97
98 /*
99 * Use minix fs values for the number of direct and indirect blocks. The
100 * count is now exact for the minix fs except that it counts zero blocks.
101 * Everything is in units of BLOCK_SIZE until the assignment to
102 * tmp.st_blksize.
103 */
104 #define D_B 7
105 #define I_B (BLOCK_SIZE / sizeof(unsigned short))
106
107 if (!inode->i_blksize) {
108 blocks = (tmp.st_size + BLOCK_SIZE - 1) / BLOCK_SIZE;
109 if (blocks > D_B) {
110 indirect = (blocks - D_B + I_B - 1) / I_B;
111 blocks += indirect;
112 if (indirect > 1) {
113 indirect = (indirect - 1 + I_B - 1) / I_B;
114 blocks += indirect;
115 if (indirect > 1)
116 blocks++;
117 }
118 }
119 tmp.st_blocks = (BLOCK_SIZE / 512) * blocks;
120 tmp.st_blksize = BLOCK_SIZE;
121 } else {
122 tmp.st_blocks = inode->i_blocks;
123 tmp.st_blksize = inode->i_blksize;
124 }
125 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
126 }
127
128
129 #if !defined(__alpha__) && !defined(__sparc__) && !defined(__ia64__) && !defined(__s390__) && !defined(__hppa__)
130 /*
131 * For backward compatibility? Maybe this should be moved
132 * into arch/i386 instead?
133 */
134 asmlinkage long sys_stat(char * filename, struct __old_kernel_stat * statbuf)
135 {
136 struct nameidata nd;
137 int error;
138
139 error = user_path_walk(filename, &nd);
140 if (!error) {
141 error = do_revalidate(nd.dentry);
142 if (!error)
143 error = cp_old_stat(nd.dentry->d_inode, statbuf);
144 path_release(&nd);
145 }
146 return error;
147 }
148 #endif
149
150 asmlinkage long sys_newstat(char * filename, struct stat * statbuf)
151 {
152 struct nameidata nd;
153 int error;
154
155 error = user_path_walk(filename, &nd);
156 if (!error) {
157 error = do_revalidate(nd.dentry);
158 if (!error)
159 error = cp_new_stat(nd.dentry->d_inode, statbuf);
160 path_release(&nd);
161 }
162 return error;
163 }
164
165 #if !defined(__alpha__) && !defined(__sparc__) && !defined(__ia64__) && !defined(__s390__) && !defined(__hppa__)
166
167 /*
168 * For backward compatibility? Maybe this should be moved
169 * into arch/i386 instead?
170 */
171 asmlinkage long sys_lstat(char * filename, struct __old_kernel_stat * statbuf)
172 {
173 struct nameidata nd;
174 int error;
175
176 error = user_path_walk_link(filename, &nd);
177 if (!error) {
178 error = do_revalidate(nd.dentry);
179 if (!error)
180 error = cp_old_stat(nd.dentry->d_inode, statbuf);
181 path_release(&nd);
182 }
183 return error;
184 }
185
186 #endif
187
188 asmlinkage long sys_newlstat(char * filename, struct stat * statbuf)
189 {
190 struct nameidata nd;
191 int error;
192
193 error = user_path_walk_link(filename, &nd);
194 if (!error) {
195 error = do_revalidate(nd.dentry);
196 if (!error)
197 error = cp_new_stat(nd.dentry->d_inode, statbuf);
198 path_release(&nd);
199 }
200 return error;
201 }
202
203 #if !defined(__alpha__) && !defined(__sparc__) && !defined(__ia64__) && !defined(__s390__) && !defined(__hppa__)
204
205 /*
206 * For backward compatibility? Maybe this should be moved
207 * into arch/i386 instead?
208 */
209 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat * statbuf)
210 {
211 struct file * f;
212 int err = -EBADF;
213
214 f = fget(fd);
215 if (f) {
216 struct dentry * dentry = f->f_dentry;
217
218 err = do_revalidate(dentry);
219 if (!err)
220 err = cp_old_stat(dentry->d_inode, statbuf);
221 fput(f);
222 }
223 return err;
224 }
225
226 #endif
227
228 asmlinkage long sys_newfstat(unsigned int fd, struct stat * statbuf)
229 {
230 struct file * f;
231 int err = -EBADF;
232
233 f = fget(fd);
234 if (f) {
235 struct dentry * dentry = f->f_dentry;
236
237 err = do_revalidate(dentry);
238 if (!err)
239 err = cp_new_stat(dentry->d_inode, statbuf);
240 fput(f);
241 }
242 return err;
243 }
244
245 asmlinkage long sys_readlink(const char * path, char * buf, int bufsiz)
246 {
247 struct nameidata nd;
248 int error;
249
250 if (bufsiz <= 0)
251 return -EINVAL;
252
253 error = user_path_walk_link(path, &nd);
254 if (!error) {
255 struct inode * inode = nd.dentry->d_inode;
256
257 error = -EINVAL;
258 if (inode->i_op && inode->i_op->readlink &&
259 !(error = do_revalidate(nd.dentry))) {
260 UPDATE_ATIME(inode);
261 error = inode->i_op->readlink(nd.dentry, buf, bufsiz);
262 }
263 path_release(&nd);
264 }
265 return error;
266 }
267
268
269 /* ---------- LFS-64 ----------- */
270 #if !defined(__alpha__) && !defined (__ia64__) && !defined(__mips64)
271
272 static long cp_new_stat64(struct inode * inode, struct stat64 * statbuf)
273 {
274 struct stat64 tmp;
275 unsigned int blocks, indirect;
276
277 memset(&tmp, 0, sizeof(tmp));
278 tmp.st_dev = kdev_t_to_nr(inode->i_dev);
279 tmp.st_ino = inode->i_ino;
280 #ifdef STAT64_HAS_BROKEN_ST_INO
281 tmp.__st_ino = inode->i_ino;
282 #endif
283 tmp.st_mode = inode->i_mode;
284 tmp.st_nlink = inode->i_nlink;
285 tmp.st_uid = inode->i_uid;
286 tmp.st_gid = inode->i_gid;
287 tmp.st_rdev = kdev_t_to_nr(inode->i_rdev);
288 tmp.st_atime = inode->i_atime;
289 tmp.st_mtime = inode->i_mtime;
290 tmp.st_ctime = inode->i_ctime;
291 tmp.st_size = inode->i_size;
292 /*
293 * st_blocks and st_blksize are approximated with a simple algorithm if
294 * they aren't supported directly by the filesystem. The minix and msdos
295 * filesystems don't keep track of blocks, so they would either have to
296 * be counted explicitly (by delving into the file itself), or by using
297 * this simple algorithm to get a reasonable (although not 100% accurate)
298 * value.
299 */
300
301 /*
302 * Use minix fs values for the number of direct and indirect blocks. The
303 * count is now exact for the minix fs except that it counts zero blocks.
304 * Everything is in units of BLOCK_SIZE until the assignment to
305 * tmp.st_blksize.
306 */
307 #define D_B 7
308 #define I_B (BLOCK_SIZE / sizeof(unsigned short))
309
310 if (!inode->i_blksize) {
311 blocks = (tmp.st_size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
312 if (blocks > D_B) {
313 indirect = (blocks - D_B + I_B - 1) / I_B;
314 blocks += indirect;
315 if (indirect > 1) {
316 indirect = (indirect - 1 + I_B - 1) / I_B;
317 blocks += indirect;
318 if (indirect > 1)
319 blocks++;
320 }
321 }
322 tmp.st_blocks = (BLOCK_SIZE / 512) * blocks;
323 tmp.st_blksize = BLOCK_SIZE;
324 } else {
325 tmp.st_blocks = inode->i_blocks;
326 tmp.st_blksize = inode->i_blksize;
327 }
328 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
329 }
330
331 asmlinkage long sys_stat64(char * filename, struct stat64 * statbuf, long flags)
332 {
333 struct nameidata nd;
334 int error;
335
336 error = user_path_walk(filename, &nd);
337 if (!error) {
338 error = do_revalidate(nd.dentry);
339 if (!error)
340 error = cp_new_stat64(nd.dentry->d_inode, statbuf);
341 path_release(&nd);
342 }
343 return error;
344 }
345
346 asmlinkage long sys_lstat64(char * filename, struct stat64 * statbuf, long flags)
347 {
348 struct nameidata nd;
349 int error;
350
351 error = user_path_walk_link(filename, &nd);
352 if (!error) {
353 error = do_revalidate(nd.dentry);
354 if (!error)
355 error = cp_new_stat64(nd.dentry->d_inode, statbuf);
356 path_release(&nd);
357 }
358 return error;
359 }
360
361 asmlinkage long sys_fstat64(unsigned long fd, struct stat64 * statbuf, long flags)
362 {
363 struct file * f;
364 int err = -EBADF;
365
366 f = fget(fd);
367 if (f) {
368 struct dentry * dentry = f->f_dentry;
369
370 err = do_revalidate(dentry);
371 if (!err)
372 err = cp_new_stat64(dentry->d_inode, statbuf);
373 fput(f);
374 }
375 return err;
376 }
377
378 #endif /* LFS-64 */
379
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