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
21void 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
38EXPORT_SYMBOL(generic_fillattr);
39
40int 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
56EXPORT_SYMBOL(vfs_getattr);
57
58int vfs_fstat(unsigned int fd, struct kstat *stat)
59{
60	struct file *f = fget(fd);
61	int error = -EBADF;
62
63	if (f) {
64		error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat);
65		fput(f);
66	}
67	return error;
68}
69EXPORT_SYMBOL(vfs_fstat);
70
71int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
72		int flag)
73{
74	struct path path;
75	int error = -EINVAL;
76	int lookup_flags = 0;
77
78	if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
79		goto out;
80
81	if (!(flag & AT_SYMLINK_NOFOLLOW))
82		lookup_flags |= LOOKUP_FOLLOW;
83
84	error = user_path_at(dfd, filename, lookup_flags, &path);
85	if (error)
86		goto out;
87
88	error = vfs_getattr(path.mnt, path.dentry, stat);
89	path_put(&path);
90out:
91	return error;
92}
93EXPORT_SYMBOL(vfs_fstatat);
94
95int vfs_stat(const char __user *name, struct kstat *stat)
96{
97	return vfs_fstatat(AT_FDCWD, name, stat, 0);
98}
99EXPORT_SYMBOL(vfs_stat);
100
101int vfs_lstat(const char __user *name, struct kstat *stat)
102{
103	return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
104}
105EXPORT_SYMBOL(vfs_lstat);
106
107
108#ifdef __ARCH_WANT_OLD_STAT
109
110/*
111 * For backward compatibility?  Maybe this should be moved
112 * into arch/i386 instead?
113 */
114static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
115{
116	static int warncount = 5;
117	struct __old_kernel_stat tmp;
118
119	if (warncount > 0) {
120		warncount--;
121		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
122			current->comm);
123	} else if (warncount < 0) {
124		/* it's laughable, but... */
125		warncount = 0;
126	}
127
128	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
129	tmp.st_dev = old_encode_dev(stat->dev);
130	tmp.st_ino = stat->ino;
131	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
132		return -EOVERFLOW;
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
151SYSCALL_DEFINE2(stat, const char __user *, filename,
152		struct __old_kernel_stat __user *, statbuf)
153{
154	struct kstat stat;
155	int error;
156
157	error = vfs_stat(filename, &stat);
158	if (error)
159		return error;
160
161	return cp_old_stat(&stat, statbuf);
162}
163
164SYSCALL_DEFINE2(lstat, const char __user *, filename,
165		struct __old_kernel_stat __user *, statbuf)
166{
167	struct kstat stat;
168	int error;
169
170	error = vfs_lstat(filename, &stat);
171	if (error)
172		return error;
173
174	return cp_old_stat(&stat, statbuf);
175}
176
177SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
178{
179	struct kstat stat;
180	int error = vfs_fstat(fd, &stat);
181
182	if (!error)
183		error = cp_old_stat(&stat, statbuf);
184
185	return error;
186}
187
188#endif /* __ARCH_WANT_OLD_STAT */
189
190static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
191{
192	struct stat tmp;
193
194#if BITS_PER_LONG == 32
195	if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
196		return -EOVERFLOW;
197#else
198	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
199		return -EOVERFLOW;
200#endif
201
202	memset(&tmp, 0, sizeof(tmp));
203#if BITS_PER_LONG == 32
204	tmp.st_dev = old_encode_dev(stat->dev);
205#else
206	tmp.st_dev = new_encode_dev(stat->dev);
207#endif
208	tmp.st_ino = stat->ino;
209	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
210		return -EOVERFLOW;
211	tmp.st_mode = stat->mode;
212	tmp.st_nlink = stat->nlink;
213	if (tmp.st_nlink != stat->nlink)
214		return -EOVERFLOW;
215	SET_UID(tmp.st_uid, stat->uid);
216	SET_GID(tmp.st_gid, stat->gid);
217#if BITS_PER_LONG == 32
218	tmp.st_rdev = old_encode_dev(stat->rdev);
219#else
220	tmp.st_rdev = new_encode_dev(stat->rdev);
221#endif
222#if BITS_PER_LONG == 32
223	if (stat->size > MAX_NON_LFS)
224		return -EOVERFLOW;
225#endif
226	tmp.st_size = stat->size;
227	tmp.st_atime = stat->atime.tv_sec;
228	tmp.st_mtime = stat->mtime.tv_sec;
229	tmp.st_ctime = stat->ctime.tv_sec;
230#ifdef STAT_HAVE_NSEC
231	tmp.st_atime_nsec = stat->atime.tv_nsec;
232	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
233	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
234#endif
235	tmp.st_blocks = stat->blocks;
236	tmp.st_blksize = stat->blksize;
237	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
238}
239
240SYSCALL_DEFINE2(newstat, const char __user *, filename,
241		struct stat __user *, statbuf)
242{
243	struct kstat stat;
244	int error = vfs_stat(filename, &stat);
245
246	if (error)
247		return error;
248	return cp_new_stat(&stat, statbuf);
249}
250
251SYSCALL_DEFINE2(newlstat, const char __user *, filename,
252		struct stat __user *, statbuf)
253{
254	struct kstat stat;
255	int error;
256
257	error = vfs_lstat(filename, &stat);
258	if (error)
259		return error;
260
261	return cp_new_stat(&stat, statbuf);
262}
263
264#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
265SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
266		struct stat __user *, statbuf, int, flag)
267{
268	struct kstat stat;
269	int error;
270
271	error = vfs_fstatat(dfd, filename, &stat, flag);
272	if (error)
273		return error;
274	return cp_new_stat(&stat, statbuf);
275}
276#endif
277
278SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
279{
280	struct kstat stat;
281	int error = vfs_fstat(fd, &stat);
282
283	if (!error)
284		error = cp_new_stat(&stat, statbuf);
285
286	return error;
287}
288
289SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
290		char __user *, buf, int, bufsiz)
291{
292	struct path path;
293	int error;
294
295	if (bufsiz <= 0)
296		return -EINVAL;
297
298	error = user_path_at(dfd, pathname, 0, &path);
299	if (!error) {
300		struct inode *inode = path.dentry->d_inode;
301
302		error = -EINVAL;
303		if (inode->i_op->readlink) {
304			error = security_inode_readlink(path.dentry);
305			if (!error) {
306				touch_atime(path.mnt, path.dentry);
307				error = inode->i_op->readlink(path.dentry,
308							      buf, bufsiz);
309			}
310		}
311		path_put(&path);
312	}
313	return error;
314}
315
316SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
317		int, bufsiz)
318{
319	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
320}
321
322
323/* ---------- LFS-64 ----------- */
324#ifdef __ARCH_WANT_STAT64
325
326static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
327{
328	struct stat64 tmp;
329
330	memset(&tmp, 0, sizeof(struct stat64));
331#ifdef CONFIG_MIPS
332	/* mips has weird padding, so we don't get 64 bits there */
333	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
334		return -EOVERFLOW;
335	tmp.st_dev = new_encode_dev(stat->dev);
336	tmp.st_rdev = new_encode_dev(stat->rdev);
337#else
338	tmp.st_dev = huge_encode_dev(stat->dev);
339	tmp.st_rdev = huge_encode_dev(stat->rdev);
340#endif
341	tmp.st_ino = stat->ino;
342	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
343		return -EOVERFLOW;
344#ifdef STAT64_HAS_BROKEN_ST_INO
345	tmp.__st_ino = stat->ino;
346#endif
347	tmp.st_mode = stat->mode;
348	tmp.st_nlink = stat->nlink;
349	tmp.st_uid = stat->uid;
350	tmp.st_gid = stat->gid;
351	tmp.st_atime = stat->atime.tv_sec;
352	tmp.st_atime_nsec = stat->atime.tv_nsec;
353	tmp.st_mtime = stat->mtime.tv_sec;
354	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
355	tmp.st_ctime = stat->ctime.tv_sec;
356	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
357	tmp.st_size = stat->size;
358	tmp.st_blocks = stat->blocks;
359	tmp.st_blksize = stat->blksize;
360	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
361}
362
363SYSCALL_DEFINE2(stat64, const char __user *, filename,
364		struct stat64 __user *, statbuf)
365{
366	struct kstat stat;
367	int error = vfs_stat(filename, &stat);
368
369	if (!error)
370		error = cp_new_stat64(&stat, statbuf);
371
372	return error;
373}
374
375SYSCALL_DEFINE2(lstat64, const char __user *, filename,
376		struct stat64 __user *, statbuf)
377{
378	struct kstat stat;
379	int error = vfs_lstat(filename, &stat);
380
381	if (!error)
382		error = cp_new_stat64(&stat, statbuf);
383
384	return error;
385}
386
387SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
388{
389	struct kstat stat;
390	int error = vfs_fstat(fd, &stat);
391
392	if (!error)
393		error = cp_new_stat64(&stat, statbuf);
394
395	return error;
396}
397
398SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
399		struct stat64 __user *, statbuf, int, flag)
400{
401	struct kstat stat;
402	int error;
403
404	error = vfs_fstatat(dfd, filename, &stat, flag);
405	if (error)
406		return error;
407	return cp_new_stat64(&stat, statbuf);
408}
409#endif /* __ARCH_WANT_STAT64 */
410
411/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
412void __inode_add_bytes(struct inode *inode, loff_t bytes)
413{
414	inode->i_blocks += bytes >> 9;
415	bytes &= 511;
416	inode->i_bytes += bytes;
417	if (inode->i_bytes >= 512) {
418		inode->i_blocks++;
419		inode->i_bytes -= 512;
420	}
421}
422
423void inode_add_bytes(struct inode *inode, loff_t bytes)
424{
425	spin_lock(&inode->i_lock);
426	__inode_add_bytes(inode, bytes);
427	spin_unlock(&inode->i_lock);
428}
429
430EXPORT_SYMBOL(inode_add_bytes);
431
432void inode_sub_bytes(struct inode *inode, loff_t bytes)
433{
434	spin_lock(&inode->i_lock);
435	inode->i_blocks -= bytes >> 9;
436	bytes &= 511;
437	if (inode->i_bytes < bytes) {
438		inode->i_blocks--;
439		inode->i_bytes += 512;
440	}
441	inode->i_bytes -= bytes;
442	spin_unlock(&inode->i_lock);
443}
444
445EXPORT_SYMBOL(inode_sub_bytes);
446
447loff_t inode_get_bytes(struct inode *inode)
448{
449	loff_t ret;
450
451	spin_lock(&inode->i_lock);
452	ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
453	spin_unlock(&inode->i_lock);
454	return ret;
455}
456
457EXPORT_SYMBOL(inode_get_bytes);
458
459void inode_set_bytes(struct inode *inode, loff_t bytes)
460{
461	/* Caller is here responsible for sufficient locking
462	 * (ie. inode->i_lock) */
463	inode->i_blocks = bytes >> 9;
464	inode->i_bytes = bytes & 511;
465}
466
467EXPORT_SYMBOL(inode_set_bytes);
468