/fs/stat.c

  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->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
 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 | AT_NO_AUTOMOUNT |
 79		      AT_EMPTY_PATH)) != 0)
 80		goto out;
 81
 82	if (!(flag & AT_SYMLINK_NOFOLLOW))
 83		lookup_flags |= LOOKUP_FOLLOW;
 84	if (flag & AT_EMPTY_PATH)
 85		lookup_flags |= LOOKUP_EMPTY;
 86
 87	error = user_path_at(dfd, filename, lookup_flags, &path);
 88	if (error)
 89		goto out;
 90
 91	error = vfs_getattr(path.mnt, path.dentry, stat);
 92	path_put(&path);
 93out:
 94	return error;
 95}
 96EXPORT_SYMBOL(vfs_fstatat);
 97
 98int vfs_stat(const char __user *name, struct kstat *stat)
 99{
100	return vfs_fstatat(AT_FDCWD, name, stat, 0);
101}
102EXPORT_SYMBOL(vfs_stat);
103
104int vfs_lstat(const char __user *name, struct kstat *stat)
105{
106	return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW);
107}
108EXPORT_SYMBOL(vfs_lstat);
109
110
111#ifdef __ARCH_WANT_OLD_STAT
112
113/*
114 * For backward compatibility?  Maybe this should be moved
115 * into arch/i386 instead?
116 */
117static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
118{
119	static int warncount = 5;
120	struct __old_kernel_stat tmp;
121	
122	if (warncount > 0) {
123		warncount--;
124		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
125			current->comm);
126	} else if (warncount < 0) {
127		/* it's laughable, but... */
128		warncount = 0;
129	}
130
131	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
132	tmp.st_dev = old_encode_dev(stat->dev);
133	tmp.st_ino = stat->ino;
134	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
135		return -EOVERFLOW;
136	tmp.st_mode = stat->mode;
137	tmp.st_nlink = stat->nlink;
138	if (tmp.st_nlink != stat->nlink)
139		return -EOVERFLOW;
140	SET_UID(tmp.st_uid, stat->uid);
141	SET_GID(tmp.st_gid, stat->gid);
142	tmp.st_rdev = old_encode_dev(stat->rdev);
143#if BITS_PER_LONG == 32
144	if (stat->size > MAX_NON_LFS)
145		return -EOVERFLOW;
146#endif	
147	tmp.st_size = stat->size;
148	tmp.st_atime = stat->atime.tv_sec;
149	tmp.st_mtime = stat->mtime.tv_sec;
150	tmp.st_ctime = stat->ctime.tv_sec;
151	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
152}
153
154SYSCALL_DEFINE2(stat, const char __user *, filename,
155		struct __old_kernel_stat __user *, statbuf)
156{
157	struct kstat stat;
158	int error;
159
160	error = vfs_stat(filename, &stat);
161	if (error)
162		return error;
163
164	return cp_old_stat(&stat, statbuf);
165}
166
167SYSCALL_DEFINE2(lstat, const char __user *, filename,
168		struct __old_kernel_stat __user *, statbuf)
169{
170	struct kstat stat;
171	int error;
172
173	error = vfs_lstat(filename, &stat);
174	if (error)
175		return error;
176
177	return cp_old_stat(&stat, statbuf);
178}
179
180SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
181{
182	struct kstat stat;
183	int error = vfs_fstat(fd, &stat);
184
185	if (!error)
186		error = cp_old_stat(&stat, statbuf);
187
188	return error;
189}
190
191#endif /* __ARCH_WANT_OLD_STAT */
192
193static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
194{
195	struct stat tmp;
196
197#if BITS_PER_LONG == 32
198	if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
199		return -EOVERFLOW;
200#else
201	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
202		return -EOVERFLOW;
203#endif
204
205	memset(&tmp, 0, sizeof(tmp));
206#if BITS_PER_LONG == 32
207	tmp.st_dev = old_encode_dev(stat->dev);
208#else
209	tmp.st_dev = new_encode_dev(stat->dev);
210#endif
211	tmp.st_ino = stat->ino;
212	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
213		return -EOVERFLOW;
214	tmp.st_mode = stat->mode;
215	tmp.st_nlink = stat->nlink;
216	if (tmp.st_nlink != stat->nlink)
217		return -EOVERFLOW;
218	SET_UID(tmp.st_uid, stat->uid);
219	SET_GID(tmp.st_gid, stat->gid);
220#if BITS_PER_LONG == 32
221	tmp.st_rdev = old_encode_dev(stat->rdev);
222#else
223	tmp.st_rdev = new_encode_dev(stat->rdev);
224#endif
225#if BITS_PER_LONG == 32
226	if (stat->size > MAX_NON_LFS)
227		return -EOVERFLOW;
228#endif	
229	tmp.st_size = stat->size;
230	tmp.st_atime = stat->atime.tv_sec;
231	tmp.st_mtime = stat->mtime.tv_sec;
232	tmp.st_ctime = stat->ctime.tv_sec;
233#ifdef STAT_HAVE_NSEC
234	tmp.st_atime_nsec = stat->atime.tv_nsec;
235	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
236	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
237#endif
238	tmp.st_blocks = stat->blocks;
239	tmp.st_blksize = stat->blksize;
240	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
241}
242
243SYSCALL_DEFINE2(newstat, const char __user *, filename,
244		struct stat __user *, statbuf)
245{
246	struct kstat stat;
247	int error = vfs_stat(filename, &stat);
248
249	if (error)
250		return error;
251	return cp_new_stat(&stat, statbuf);
252}
253
254SYSCALL_DEFINE2(newlstat, const char __user *, filename,
255		struct stat __user *, statbuf)
256{
257	struct kstat stat;
258	int error;
259
260	error = vfs_lstat(filename, &stat);
261	if (error)
262		return error;
263
264	return cp_new_stat(&stat, statbuf);
265}
266
267#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
268SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
269		struct stat __user *, statbuf, int, flag)
270{
271	struct kstat stat;
272	int error;
273
274	error = vfs_fstatat(dfd, filename, &stat, flag);
275	if (error)
276		return error;
277	return cp_new_stat(&stat, statbuf);
278}
279#endif
280
281SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
282{
283	struct kstat stat;
284	int error = vfs_fstat(fd, &stat);
285
286	if (!error)
287		error = cp_new_stat(&stat, statbuf);
288
289	return error;
290}
291
292SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
293		char __user *, buf, int, bufsiz)
294{
295	struct path path;
296	int error;
297	int empty = 0;
298
299	if (bufsiz <= 0)
300		return -EINVAL;
301
302	error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);
303	if (!error) {
304		struct inode *inode = path.dentry->d_inode;
305
306		error = empty ? -ENOENT : -EINVAL;
307		if (inode->i_op->readlink) {
308			error = security_inode_readlink(path.dentry);
309			if (!error) {
310				touch_atime(path.mnt, path.dentry);
311				error = inode->i_op->readlink(path.dentry,
312							      buf, bufsiz);
313			}
314		}
315		path_put(&path);
316	}
317	return error;
318}
319
320SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
321		int, bufsiz)
322{
323	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
324}
325
326
327/* ---------- LFS-64 ----------- */
328#ifdef __ARCH_WANT_STAT64
329
330static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
331{
332	struct stat64 tmp;
333
334	memset(&tmp, 0, sizeof(struct stat64));
335#ifdef CONFIG_MIPS
336	/* mips has weird padding, so we don't get 64 bits there */
337	if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
338		return -EOVERFLOW;
339	tmp.st_dev = new_encode_dev(stat->dev);
340	tmp.st_rdev = new_encode_dev(stat->rdev);
341#else
342	tmp.st_dev = huge_encode_dev(stat->dev);
343	tmp.st_rdev = huge_encode_dev(stat->rdev);
344#endif
345	tmp.st_ino = stat->ino;
346	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
347		return -EOVERFLOW;
348#ifdef STAT64_HAS_BROKEN_ST_INO
349	tmp.__st_ino = stat->ino;
350#endif
351	tmp.st_mode = stat->mode;
352	tmp.st_nlink = stat->nlink;
353	tmp.st_uid = stat->uid;
354	tmp.st_gid = stat->gid;
355	tmp.st_atime = stat->atime.tv_sec;
356	tmp.st_atime_nsec = stat->atime.tv_nsec;
357	tmp.st_mtime = stat->mtime.tv_sec;
358	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
359	tmp.st_ctime = stat->ctime.tv_sec;
360	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
361	tmp.st_size = stat->size;
362	tmp.st_blocks = stat->blocks;
363	tmp.st_blksize = stat->blksize;
364	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
365}
366
367SYSCALL_DEFINE2(stat64, const char __user *, filename,
368		struct stat64 __user *, statbuf)
369{
370	struct kstat stat;
371	int error = vfs_stat(filename, &stat);
372
373	if (!error)
374		error = cp_new_stat64(&stat, statbuf);
375
376	return error;
377}
378
379SYSCALL_DEFINE2(lstat64, const char __user *, filename,
380		struct stat64 __user *, statbuf)
381{
382	struct kstat stat;
383	int error = vfs_lstat(filename, &stat);
384
385	if (!error)
386		error = cp_new_stat64(&stat, statbuf);
387
388	return error;
389}
390
391SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
392{
393	struct kstat stat;
394	int error = vfs_fstat(fd, &stat);
395
396	if (!error)
397		error = cp_new_stat64(&stat, statbuf);
398
399	return error;
400}
401
402SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
403		struct stat64 __user *, statbuf, int, flag)
404{
405	struct kstat stat;
406	int error;
407
408	error = vfs_fstatat(dfd, filename, &stat, flag);
409	if (error)
410		return error;
411	return cp_new_stat64(&stat, statbuf);
412}
413#endif /* __ARCH_WANT_STAT64 */
414
415/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
416void __inode_add_bytes(struct inode *inode, loff_t bytes)
417{
418	inode->i_blocks += bytes >> 9;
419	bytes &= 511;
420	inode->i_bytes += bytes;
421	if (inode->i_bytes >= 512) {
422		inode->i_blocks++;
423		inode->i_bytes -= 512;
424	}
425}
426
427void inode_add_bytes(struct inode *inode, loff_t bytes)
428{
429	spin_lock(&inode->i_lock);
430	__inode_add_bytes(inode, bytes);
431	spin_unlock(&inode->i_lock);
432}
433
434EXPORT_SYMBOL(inode_add_bytes);
435
436void inode_sub_bytes(struct inode *inode, loff_t bytes)
437{
438	spin_lock(&inode->i_lock);
439	inode->i_blocks -= bytes >> 9;
440	bytes &= 511;
441	if (inode->i_bytes < bytes) {
442		inode->i_blocks--;
443		inode->i_bytes += 512;
444	}
445	inode->i_bytes -= bytes;
446	spin_unlock(&inode->i_lock);
447}
448
449EXPORT_SYMBOL(inode_sub_bytes);
450
451loff_t inode_get_bytes(struct inode *inode)
452{
453	loff_t ret;
454
455	spin_lock(&inode->i_lock);
456	ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
457	spin_unlock(&inode->i_lock);
458	return ret;
459}
460
461EXPORT_SYMBOL(inode_get_bytes);
462
463void inode_set_bytes(struct inode *inode, loff_t bytes)
464{
465	/* Caller is here responsible for sufficient locking
466	 * (ie. inode->i_lock) */
467	inode->i_blocks = bytes >> 9;
468	inode->i_bytes = bytes & 511;
469}
470
471EXPORT_SYMBOL(inode_set_bytes);