xref: /openbmc/linux/fs/stat.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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