xref: /openbmc/linux/fs/stat.c (revision 60630924bb5af8751adcecc896e7763c3783ca89)
1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   *  linux/fs/stat.c
4   *
5   *  Copyright (C) 1991, 1992  Linus Torvalds
6   */
7  
8  #include <linux/export.h>
9  #include <linux/mm.h>
10  #include <linux/errno.h>
11  #include <linux/file.h>
12  #include <linux/highuid.h>
13  #include <linux/fs.h>
14  #include <linux/namei.h>
15  #include <linux/security.h>
16  #include <linux/cred.h>
17  #include <linux/syscalls.h>
18  #include <linux/pagemap.h>
19  #include <linux/compat.h>
20  
21  #include <linux/uaccess.h>
22  #include <asm/unistd.h>
23  
24  #include "internal.h"
25  #include "mount.h"
26  
27  /**
28   * generic_fillattr - Fill in the basic attributes from the inode struct
29   * @mnt_userns:	user namespace of the mount the inode was found from
30   * @inode:	Inode to use as the source
31   * @stat:	Where to fill in the attributes
32   *
33   * Fill in the basic attributes in the kstat structure from data that's to be
34   * found on the VFS inode structure.  This is the default if no getattr inode
35   * operation is supplied.
36   *
37   * If the inode has been found through an idmapped mount the user namespace of
38   * the vfsmount must be passed through @mnt_userns. This function will then
39   * take care to map the inode according to @mnt_userns before filling in the
40   * uid and gid filds. On non-idmapped mounts or if permission checking is to be
41   * performed on the raw inode simply passs init_user_ns.
42   */
43  void generic_fillattr(struct user_namespace *mnt_userns, struct inode *inode,
44  		      struct kstat *stat)
45  {
46  	stat->dev = inode->i_sb->s_dev;
47  	stat->ino = inode->i_ino;
48  	stat->mode = inode->i_mode;
49  	stat->nlink = inode->i_nlink;
50  	stat->uid = i_uid_into_mnt(mnt_userns, inode);
51  	stat->gid = i_gid_into_mnt(mnt_userns, inode);
52  	stat->rdev = inode->i_rdev;
53  	stat->size = i_size_read(inode);
54  	stat->atime = inode->i_atime;
55  	stat->mtime = inode->i_mtime;
56  	stat->ctime = inode->i_ctime;
57  	stat->blksize = i_blocksize(inode);
58  	stat->blocks = inode->i_blocks;
59  }
60  EXPORT_SYMBOL(generic_fillattr);
61  
62  /**
63   * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
64   * @inode:	Inode to use as the source
65   * @stat:	Where to fill in the attribute flags
66   *
67   * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
68   * inode that are published on i_flags and enforced by the VFS.
69   */
70  void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
71  {
72  	if (inode->i_flags & S_IMMUTABLE)
73  		stat->attributes |= STATX_ATTR_IMMUTABLE;
74  	if (inode->i_flags & S_APPEND)
75  		stat->attributes |= STATX_ATTR_APPEND;
76  	stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
77  }
78  EXPORT_SYMBOL(generic_fill_statx_attr);
79  
80  /**
81   * vfs_getattr_nosec - getattr without security checks
82   * @path: file to get attributes from
83   * @stat: structure to return attributes in
84   * @request_mask: STATX_xxx flags indicating what the caller wants
85   * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
86   *
87   * Get attributes without calling security_inode_getattr.
88   *
89   * Currently the only caller other than vfs_getattr is internal to the
90   * filehandle lookup code, which uses only the inode number and returns no
91   * attributes to any user.  Any other code probably wants vfs_getattr.
92   */
93  int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
94  		      u32 request_mask, unsigned int query_flags)
95  {
96  	struct user_namespace *mnt_userns;
97  	struct inode *inode = d_backing_inode(path->dentry);
98  
99  	memset(stat, 0, sizeof(*stat));
100  	stat->result_mask |= STATX_BASIC_STATS;
101  	query_flags &= AT_STATX_SYNC_TYPE;
102  
103  	/* allow the fs to override these if it really wants to */
104  	/* SB_NOATIME means filesystem supplies dummy atime value */
105  	if (inode->i_sb->s_flags & SB_NOATIME)
106  		stat->result_mask &= ~STATX_ATIME;
107  
108  	/*
109  	 * Note: If you add another clause to set an attribute flag, please
110  	 * update attributes_mask below.
111  	 */
112  	if (IS_AUTOMOUNT(inode))
113  		stat->attributes |= STATX_ATTR_AUTOMOUNT;
114  
115  	if (IS_DAX(inode))
116  		stat->attributes |= STATX_ATTR_DAX;
117  
118  	stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
119  				  STATX_ATTR_DAX);
120  
121  	mnt_userns = mnt_user_ns(path->mnt);
122  	if (inode->i_op->getattr)
123  		return inode->i_op->getattr(mnt_userns, path, stat,
124  					    request_mask, query_flags);
125  
126  	generic_fillattr(mnt_userns, inode, stat);
127  	return 0;
128  }
129  EXPORT_SYMBOL(vfs_getattr_nosec);
130  
131  /*
132   * vfs_getattr - Get the enhanced basic attributes of a file
133   * @path: The file of interest
134   * @stat: Where to return the statistics
135   * @request_mask: STATX_xxx flags indicating what the caller wants
136   * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
137   *
138   * Ask the filesystem for a file's attributes.  The caller must indicate in
139   * request_mask and query_flags to indicate what they want.
140   *
141   * If the file is remote, the filesystem can be forced to update the attributes
142   * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
143   * suppress the update by passing AT_STATX_DONT_SYNC.
144   *
145   * Bits must have been set in request_mask to indicate which attributes the
146   * caller wants retrieving.  Any such attribute not requested may be returned
147   * anyway, but the value may be approximate, and, if remote, may not have been
148   * synchronised with the server.
149   *
150   * 0 will be returned on success, and a -ve error code if unsuccessful.
151   */
152  int vfs_getattr(const struct path *path, struct kstat *stat,
153  		u32 request_mask, unsigned int query_flags)
154  {
155  	int retval;
156  
157  	retval = security_inode_getattr(path);
158  	if (retval)
159  		return retval;
160  	return vfs_getattr_nosec(path, stat, request_mask, query_flags);
161  }
162  EXPORT_SYMBOL(vfs_getattr);
163  
164  /**
165   * vfs_fstat - Get the basic attributes by file descriptor
166   * @fd: The file descriptor referring to the file of interest
167   * @stat: The result structure to fill in.
168   *
169   * This function is a wrapper around vfs_getattr().  The main difference is
170   * that it uses a file descriptor to determine the file location.
171   *
172   * 0 will be returned on success, and a -ve error code if unsuccessful.
173   */
174  int vfs_fstat(int fd, struct kstat *stat)
175  {
176  	struct fd f;
177  	int error;
178  
179  	f = fdget_raw(fd);
180  	if (!f.file)
181  		return -EBADF;
182  	error = vfs_getattr(&f.file->f_path, stat, STATX_BASIC_STATS, 0);
183  	fdput(f);
184  	return error;
185  }
186  
187  /**
188   * vfs_statx - Get basic and extra attributes by filename
189   * @dfd: A file descriptor representing the base dir for a relative filename
190   * @filename: The name of the file of interest
191   * @flags: Flags to control the query
192   * @stat: The result structure to fill in.
193   * @request_mask: STATX_xxx flags indicating what the caller wants
194   *
195   * This function is a wrapper around vfs_getattr().  The main difference is
196   * that it uses a filename and base directory to determine the file location.
197   * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
198   * at the given name from being referenced.
199   *
200   * 0 will be returned on success, and a -ve error code if unsuccessful.
201   */
202  static int vfs_statx(int dfd, const char __user *filename, int flags,
203  	      struct kstat *stat, u32 request_mask)
204  {
205  	struct path path;
206  	unsigned lookup_flags = 0;
207  	int error;
208  
209  	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
210  		      AT_STATX_SYNC_TYPE))
211  		return -EINVAL;
212  
213  	if (!(flags & AT_SYMLINK_NOFOLLOW))
214  		lookup_flags |= LOOKUP_FOLLOW;
215  	if (!(flags & AT_NO_AUTOMOUNT))
216  		lookup_flags |= LOOKUP_AUTOMOUNT;
217  	if (flags & AT_EMPTY_PATH)
218  		lookup_flags |= LOOKUP_EMPTY;
219  
220  retry:
221  	error = user_path_at(dfd, filename, lookup_flags, &path);
222  	if (error)
223  		goto out;
224  
225  	error = vfs_getattr(&path, stat, request_mask, flags);
226  	stat->mnt_id = real_mount(path.mnt)->mnt_id;
227  	stat->result_mask |= STATX_MNT_ID;
228  	if (path.mnt->mnt_root == path.dentry)
229  		stat->attributes |= STATX_ATTR_MOUNT_ROOT;
230  	stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
231  	path_put(&path);
232  	if (retry_estale(error, lookup_flags)) {
233  		lookup_flags |= LOOKUP_REVAL;
234  		goto retry;
235  	}
236  out:
237  	return error;
238  }
239  
240  int vfs_fstatat(int dfd, const char __user *filename,
241  			      struct kstat *stat, int flags)
242  {
243  	return vfs_statx(dfd, filename, flags | AT_NO_AUTOMOUNT,
244  			 stat, STATX_BASIC_STATS);
245  }
246  
247  #ifdef __ARCH_WANT_OLD_STAT
248  
249  /*
250   * For backward compatibility?  Maybe this should be moved
251   * into arch/i386 instead?
252   */
253  static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
254  {
255  	static int warncount = 5;
256  	struct __old_kernel_stat tmp;
257  
258  	if (warncount > 0) {
259  		warncount--;
260  		printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
261  			current->comm);
262  	} else if (warncount < 0) {
263  		/* it's laughable, but... */
264  		warncount = 0;
265  	}
266  
267  	memset(&tmp, 0, sizeof(struct __old_kernel_stat));
268  	tmp.st_dev = old_encode_dev(stat->dev);
269  	tmp.st_ino = stat->ino;
270  	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
271  		return -EOVERFLOW;
272  	tmp.st_mode = stat->mode;
273  	tmp.st_nlink = stat->nlink;
274  	if (tmp.st_nlink != stat->nlink)
275  		return -EOVERFLOW;
276  	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
277  	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
278  	tmp.st_rdev = old_encode_dev(stat->rdev);
279  #if BITS_PER_LONG == 32
280  	if (stat->size > MAX_NON_LFS)
281  		return -EOVERFLOW;
282  #endif
283  	tmp.st_size = stat->size;
284  	tmp.st_atime = stat->atime.tv_sec;
285  	tmp.st_mtime = stat->mtime.tv_sec;
286  	tmp.st_ctime = stat->ctime.tv_sec;
287  	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
288  }
289  
290  SYSCALL_DEFINE2(stat, const char __user *, filename,
291  		struct __old_kernel_stat __user *, statbuf)
292  {
293  	struct kstat stat;
294  	int error;
295  
296  	error = vfs_stat(filename, &stat);
297  	if (error)
298  		return error;
299  
300  	return cp_old_stat(&stat, statbuf);
301  }
302  
303  SYSCALL_DEFINE2(lstat, const char __user *, filename,
304  		struct __old_kernel_stat __user *, statbuf)
305  {
306  	struct kstat stat;
307  	int error;
308  
309  	error = vfs_lstat(filename, &stat);
310  	if (error)
311  		return error;
312  
313  	return cp_old_stat(&stat, statbuf);
314  }
315  
316  SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
317  {
318  	struct kstat stat;
319  	int error = vfs_fstat(fd, &stat);
320  
321  	if (!error)
322  		error = cp_old_stat(&stat, statbuf);
323  
324  	return error;
325  }
326  
327  #endif /* __ARCH_WANT_OLD_STAT */
328  
329  #ifdef __ARCH_WANT_NEW_STAT
330  
331  #if BITS_PER_LONG == 32
332  #  define choose_32_64(a,b) a
333  #else
334  #  define choose_32_64(a,b) b
335  #endif
336  
337  #define valid_dev(x)  choose_32_64(old_valid_dev(x),true)
338  #define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)
339  
340  #ifndef INIT_STRUCT_STAT_PADDING
341  #  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
342  #endif
343  
344  static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
345  {
346  	struct stat tmp;
347  
348  	if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))
349  		return -EOVERFLOW;
350  #if BITS_PER_LONG == 32
351  	if (stat->size > MAX_NON_LFS)
352  		return -EOVERFLOW;
353  #endif
354  
355  	INIT_STRUCT_STAT_PADDING(tmp);
356  	tmp.st_dev = encode_dev(stat->dev);
357  	tmp.st_ino = stat->ino;
358  	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
359  		return -EOVERFLOW;
360  	tmp.st_mode = stat->mode;
361  	tmp.st_nlink = stat->nlink;
362  	if (tmp.st_nlink != stat->nlink)
363  		return -EOVERFLOW;
364  	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
365  	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
366  	tmp.st_rdev = encode_dev(stat->rdev);
367  	tmp.st_size = stat->size;
368  	tmp.st_atime = stat->atime.tv_sec;
369  	tmp.st_mtime = stat->mtime.tv_sec;
370  	tmp.st_ctime = stat->ctime.tv_sec;
371  #ifdef STAT_HAVE_NSEC
372  	tmp.st_atime_nsec = stat->atime.tv_nsec;
373  	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
374  	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
375  #endif
376  	tmp.st_blocks = stat->blocks;
377  	tmp.st_blksize = stat->blksize;
378  	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
379  }
380  
381  SYSCALL_DEFINE2(newstat, const char __user *, filename,
382  		struct stat __user *, statbuf)
383  {
384  	struct kstat stat;
385  	int error = vfs_stat(filename, &stat);
386  
387  	if (error)
388  		return error;
389  	return cp_new_stat(&stat, statbuf);
390  }
391  
392  SYSCALL_DEFINE2(newlstat, const char __user *, filename,
393  		struct stat __user *, statbuf)
394  {
395  	struct kstat stat;
396  	int error;
397  
398  	error = vfs_lstat(filename, &stat);
399  	if (error)
400  		return error;
401  
402  	return cp_new_stat(&stat, statbuf);
403  }
404  
405  #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
406  SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
407  		struct stat __user *, statbuf, int, flag)
408  {
409  	struct kstat stat;
410  	int error;
411  
412  	error = vfs_fstatat(dfd, filename, &stat, flag);
413  	if (error)
414  		return error;
415  	return cp_new_stat(&stat, statbuf);
416  }
417  #endif
418  
419  SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
420  {
421  	struct kstat stat;
422  	int error = vfs_fstat(fd, &stat);
423  
424  	if (!error)
425  		error = cp_new_stat(&stat, statbuf);
426  
427  	return error;
428  }
429  #endif
430  
431  static int do_readlinkat(int dfd, const char __user *pathname,
432  			 char __user *buf, int bufsiz)
433  {
434  	struct path path;
435  	int error;
436  	int empty = 0;
437  	unsigned int lookup_flags = LOOKUP_EMPTY;
438  
439  	if (bufsiz <= 0)
440  		return -EINVAL;
441  
442  retry:
443  	error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
444  	if (!error) {
445  		struct inode *inode = d_backing_inode(path.dentry);
446  
447  		error = empty ? -ENOENT : -EINVAL;
448  		/*
449  		 * AFS mountpoints allow readlink(2) but are not symlinks
450  		 */
451  		if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
452  			error = security_inode_readlink(path.dentry);
453  			if (!error) {
454  				touch_atime(&path);
455  				error = vfs_readlink(path.dentry, buf, bufsiz);
456  			}
457  		}
458  		path_put(&path);
459  		if (retry_estale(error, lookup_flags)) {
460  			lookup_flags |= LOOKUP_REVAL;
461  			goto retry;
462  		}
463  	}
464  	return error;
465  }
466  
467  SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
468  		char __user *, buf, int, bufsiz)
469  {
470  	return do_readlinkat(dfd, pathname, buf, bufsiz);
471  }
472  
473  SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
474  		int, bufsiz)
475  {
476  	return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
477  }
478  
479  
480  /* ---------- LFS-64 ----------- */
481  #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
482  
483  #ifndef INIT_STRUCT_STAT64_PADDING
484  #  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
485  #endif
486  
487  static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
488  {
489  	struct stat64 tmp;
490  
491  	INIT_STRUCT_STAT64_PADDING(tmp);
492  #ifdef CONFIG_MIPS
493  	/* mips has weird padding, so we don't get 64 bits there */
494  	tmp.st_dev = new_encode_dev(stat->dev);
495  	tmp.st_rdev = new_encode_dev(stat->rdev);
496  #else
497  	tmp.st_dev = huge_encode_dev(stat->dev);
498  	tmp.st_rdev = huge_encode_dev(stat->rdev);
499  #endif
500  	tmp.st_ino = stat->ino;
501  	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
502  		return -EOVERFLOW;
503  #ifdef STAT64_HAS_BROKEN_ST_INO
504  	tmp.__st_ino = stat->ino;
505  #endif
506  	tmp.st_mode = stat->mode;
507  	tmp.st_nlink = stat->nlink;
508  	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
509  	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
510  	tmp.st_atime = stat->atime.tv_sec;
511  	tmp.st_atime_nsec = stat->atime.tv_nsec;
512  	tmp.st_mtime = stat->mtime.tv_sec;
513  	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
514  	tmp.st_ctime = stat->ctime.tv_sec;
515  	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
516  	tmp.st_size = stat->size;
517  	tmp.st_blocks = stat->blocks;
518  	tmp.st_blksize = stat->blksize;
519  	return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
520  }
521  
522  SYSCALL_DEFINE2(stat64, const char __user *, filename,
523  		struct stat64 __user *, statbuf)
524  {
525  	struct kstat stat;
526  	int error = vfs_stat(filename, &stat);
527  
528  	if (!error)
529  		error = cp_new_stat64(&stat, statbuf);
530  
531  	return error;
532  }
533  
534  SYSCALL_DEFINE2(lstat64, const char __user *, filename,
535  		struct stat64 __user *, statbuf)
536  {
537  	struct kstat stat;
538  	int error = vfs_lstat(filename, &stat);
539  
540  	if (!error)
541  		error = cp_new_stat64(&stat, statbuf);
542  
543  	return error;
544  }
545  
546  SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
547  {
548  	struct kstat stat;
549  	int error = vfs_fstat(fd, &stat);
550  
551  	if (!error)
552  		error = cp_new_stat64(&stat, statbuf);
553  
554  	return error;
555  }
556  
557  SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
558  		struct stat64 __user *, statbuf, int, flag)
559  {
560  	struct kstat stat;
561  	int error;
562  
563  	error = vfs_fstatat(dfd, filename, &stat, flag);
564  	if (error)
565  		return error;
566  	return cp_new_stat64(&stat, statbuf);
567  }
568  #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
569  
570  static noinline_for_stack int
571  cp_statx(const struct kstat *stat, struct statx __user *buffer)
572  {
573  	struct statx tmp;
574  
575  	memset(&tmp, 0, sizeof(tmp));
576  
577  	tmp.stx_mask = stat->result_mask;
578  	tmp.stx_blksize = stat->blksize;
579  	tmp.stx_attributes = stat->attributes;
580  	tmp.stx_nlink = stat->nlink;
581  	tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
582  	tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
583  	tmp.stx_mode = stat->mode;
584  	tmp.stx_ino = stat->ino;
585  	tmp.stx_size = stat->size;
586  	tmp.stx_blocks = stat->blocks;
587  	tmp.stx_attributes_mask = stat->attributes_mask;
588  	tmp.stx_atime.tv_sec = stat->atime.tv_sec;
589  	tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
590  	tmp.stx_btime.tv_sec = stat->btime.tv_sec;
591  	tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
592  	tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
593  	tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
594  	tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
595  	tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
596  	tmp.stx_rdev_major = MAJOR(stat->rdev);
597  	tmp.stx_rdev_minor = MINOR(stat->rdev);
598  	tmp.stx_dev_major = MAJOR(stat->dev);
599  	tmp.stx_dev_minor = MINOR(stat->dev);
600  	tmp.stx_mnt_id = stat->mnt_id;
601  
602  	return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
603  }
604  
605  int do_statx(int dfd, const char __user *filename, unsigned flags,
606  	     unsigned int mask, struct statx __user *buffer)
607  {
608  	struct kstat stat;
609  	int error;
610  
611  	if (mask & STATX__RESERVED)
612  		return -EINVAL;
613  	if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
614  		return -EINVAL;
615  
616  	error = vfs_statx(dfd, filename, flags, &stat, mask);
617  	if (error)
618  		return error;
619  
620  	return cp_statx(&stat, buffer);
621  }
622  
623  /**
624   * sys_statx - System call to get enhanced stats
625   * @dfd: Base directory to pathwalk from *or* fd to stat.
626   * @filename: File to stat or "" with AT_EMPTY_PATH
627   * @flags: AT_* flags to control pathwalk.
628   * @mask: Parts of statx struct actually required.
629   * @buffer: Result buffer.
630   *
631   * Note that fstat() can be emulated by setting dfd to the fd of interest,
632   * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
633   */
634  SYSCALL_DEFINE5(statx,
635  		int, dfd, const char __user *, filename, unsigned, flags,
636  		unsigned int, mask,
637  		struct statx __user *, buffer)
638  {
639  	return do_statx(dfd, filename, flags, mask, buffer);
640  }
641  
642  #ifdef CONFIG_COMPAT
643  static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
644  {
645  	struct compat_stat tmp;
646  
647  	if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
648  		return -EOVERFLOW;
649  
650  	memset(&tmp, 0, sizeof(tmp));
651  	tmp.st_dev = old_encode_dev(stat->dev);
652  	tmp.st_ino = stat->ino;
653  	if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
654  		return -EOVERFLOW;
655  	tmp.st_mode = stat->mode;
656  	tmp.st_nlink = stat->nlink;
657  	if (tmp.st_nlink != stat->nlink)
658  		return -EOVERFLOW;
659  	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
660  	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
661  	tmp.st_rdev = old_encode_dev(stat->rdev);
662  	if ((u64) stat->size > MAX_NON_LFS)
663  		return -EOVERFLOW;
664  	tmp.st_size = stat->size;
665  	tmp.st_atime = stat->atime.tv_sec;
666  	tmp.st_atime_nsec = stat->atime.tv_nsec;
667  	tmp.st_mtime = stat->mtime.tv_sec;
668  	tmp.st_mtime_nsec = stat->mtime.tv_nsec;
669  	tmp.st_ctime = stat->ctime.tv_sec;
670  	tmp.st_ctime_nsec = stat->ctime.tv_nsec;
671  	tmp.st_blocks = stat->blocks;
672  	tmp.st_blksize = stat->blksize;
673  	return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
674  }
675  
676  COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
677  		       struct compat_stat __user *, statbuf)
678  {
679  	struct kstat stat;
680  	int error;
681  
682  	error = vfs_stat(filename, &stat);
683  	if (error)
684  		return error;
685  	return cp_compat_stat(&stat, statbuf);
686  }
687  
688  COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
689  		       struct compat_stat __user *, statbuf)
690  {
691  	struct kstat stat;
692  	int error;
693  
694  	error = vfs_lstat(filename, &stat);
695  	if (error)
696  		return error;
697  	return cp_compat_stat(&stat, statbuf);
698  }
699  
700  #ifndef __ARCH_WANT_STAT64
701  COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
702  		       const char __user *, filename,
703  		       struct compat_stat __user *, statbuf, int, flag)
704  {
705  	struct kstat stat;
706  	int error;
707  
708  	error = vfs_fstatat(dfd, filename, &stat, flag);
709  	if (error)
710  		return error;
711  	return cp_compat_stat(&stat, statbuf);
712  }
713  #endif
714  
715  COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
716  		       struct compat_stat __user *, statbuf)
717  {
718  	struct kstat stat;
719  	int error = vfs_fstat(fd, &stat);
720  
721  	if (!error)
722  		error = cp_compat_stat(&stat, statbuf);
723  	return error;
724  }
725  #endif
726  
727  /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
728  void __inode_add_bytes(struct inode *inode, loff_t bytes)
729  {
730  	inode->i_blocks += bytes >> 9;
731  	bytes &= 511;
732  	inode->i_bytes += bytes;
733  	if (inode->i_bytes >= 512) {
734  		inode->i_blocks++;
735  		inode->i_bytes -= 512;
736  	}
737  }
738  EXPORT_SYMBOL(__inode_add_bytes);
739  
740  void inode_add_bytes(struct inode *inode, loff_t bytes)
741  {
742  	spin_lock(&inode->i_lock);
743  	__inode_add_bytes(inode, bytes);
744  	spin_unlock(&inode->i_lock);
745  }
746  
747  EXPORT_SYMBOL(inode_add_bytes);
748  
749  void __inode_sub_bytes(struct inode *inode, loff_t bytes)
750  {
751  	inode->i_blocks -= bytes >> 9;
752  	bytes &= 511;
753  	if (inode->i_bytes < bytes) {
754  		inode->i_blocks--;
755  		inode->i_bytes += 512;
756  	}
757  	inode->i_bytes -= bytes;
758  }
759  
760  EXPORT_SYMBOL(__inode_sub_bytes);
761  
762  void inode_sub_bytes(struct inode *inode, loff_t bytes)
763  {
764  	spin_lock(&inode->i_lock);
765  	__inode_sub_bytes(inode, bytes);
766  	spin_unlock(&inode->i_lock);
767  }
768  
769  EXPORT_SYMBOL(inode_sub_bytes);
770  
771  loff_t inode_get_bytes(struct inode *inode)
772  {
773  	loff_t ret;
774  
775  	spin_lock(&inode->i_lock);
776  	ret = __inode_get_bytes(inode);
777  	spin_unlock(&inode->i_lock);
778  	return ret;
779  }
780  
781  EXPORT_SYMBOL(inode_get_bytes);
782  
783  void inode_set_bytes(struct inode *inode, loff_t bytes)
784  {
785  	/* Caller is here responsible for sufficient locking
786  	 * (ie. inode->i_lock) */
787  	inode->i_blocks = bytes >> 9;
788  	inode->i_bytes = bytes & 511;
789  }
790  
791  EXPORT_SYMBOL(inode_set_bytes);
792