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/blkdev.h>
9#include <linux/export.h>
10#include <linux/mm.h>
11#include <linux/errno.h>
12#include <linux/file.h>
13#include <linux/highuid.h>
14#include <linux/fs.h>
15#include <linux/namei.h>
16#include <linux/security.h>
17#include <linux/cred.h>
18#include <linux/syscalls.h>
19#include <linux/pagemap.h>
20#include <linux/compat.h>
21#include <linux/iversion.h>
22
23#include <linux/uaccess.h>
24#include <asm/unistd.h>
25
26#include "internal.h"
27#include "mount.h"
28
29/**
30 * generic_fillattr - Fill in the basic attributes from the inode struct
31 * @idmap: idmap of the mount the inode was found from
32 * @request_mask: statx request_mask
33 * @inode: Inode to use as the source
34 * @stat: Where to fill in the attributes
35 *
36 * Fill in the basic attributes in the kstat structure from data that's to be
37 * found on the VFS inode structure. This is the default if no getattr inode
38 * operation is supplied.
39 *
40 * If the inode has been found through an idmapped mount the idmap of
41 * the vfsmount must be passed through @idmap. This function will then
42 * take care to map the inode according to @idmap before filling in the
43 * uid and gid filds. On non-idmapped mounts or if permission checking is to be
44 * performed on the raw inode simply passs @nop_mnt_idmap.
45 */
46void generic_fillattr(struct mnt_idmap *idmap, u32 request_mask,
47 struct inode *inode, struct kstat *stat)
48{
49 vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
50 vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
51
52 stat->dev = inode->i_sb->s_dev;
53 stat->ino = inode->i_ino;
54 stat->mode = inode->i_mode;
55 stat->nlink = inode->i_nlink;
56 stat->uid = vfsuid_into_kuid(vfsuid);
57 stat->gid = vfsgid_into_kgid(vfsgid);
58 stat->rdev = inode->i_rdev;
59 stat->size = i_size_read(inode);
60 stat->atime = inode_get_atime(inode);
61 stat->mtime = inode_get_mtime(inode);
62 stat->ctime = inode_get_ctime(inode);
63 stat->blksize = i_blocksize(node: inode);
64 stat->blocks = inode->i_blocks;
65
66 if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) {
67 stat->result_mask |= STATX_CHANGE_COOKIE;
68 stat->change_cookie = inode_query_iversion(inode);
69 }
70
71}
72EXPORT_SYMBOL(generic_fillattr);
73
74/**
75 * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
76 * @inode: Inode to use as the source
77 * @stat: Where to fill in the attribute flags
78 *
79 * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
80 * inode that are published on i_flags and enforced by the VFS.
81 */
82void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
83{
84 if (inode->i_flags & S_IMMUTABLE)
85 stat->attributes |= STATX_ATTR_IMMUTABLE;
86 if (inode->i_flags & S_APPEND)
87 stat->attributes |= STATX_ATTR_APPEND;
88 stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
89}
90EXPORT_SYMBOL(generic_fill_statx_attr);
91
92/**
93 * vfs_getattr_nosec - getattr without security checks
94 * @path: file to get attributes from
95 * @stat: structure to return attributes in
96 * @request_mask: STATX_xxx flags indicating what the caller wants
97 * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
98 *
99 * Get attributes without calling security_inode_getattr.
100 *
101 * Currently the only caller other than vfs_getattr is internal to the
102 * filehandle lookup code, which uses only the inode number and returns no
103 * attributes to any user. Any other code probably wants vfs_getattr.
104 */
105int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
106 u32 request_mask, unsigned int query_flags)
107{
108 struct mnt_idmap *idmap;
109 struct inode *inode = d_backing_inode(upper: path->dentry);
110
111 memset(stat, 0, sizeof(*stat));
112 stat->result_mask |= STATX_BASIC_STATS;
113 query_flags &= AT_STATX_SYNC_TYPE;
114
115 /* allow the fs to override these if it really wants to */
116 /* SB_NOATIME means filesystem supplies dummy atime value */
117 if (inode->i_sb->s_flags & SB_NOATIME)
118 stat->result_mask &= ~STATX_ATIME;
119
120 /*
121 * Note: If you add another clause to set an attribute flag, please
122 * update attributes_mask below.
123 */
124 if (IS_AUTOMOUNT(inode))
125 stat->attributes |= STATX_ATTR_AUTOMOUNT;
126
127 if (IS_DAX(inode))
128 stat->attributes |= STATX_ATTR_DAX;
129
130 stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
131 STATX_ATTR_DAX);
132
133 idmap = mnt_idmap(mnt: path->mnt);
134 if (inode->i_op->getattr)
135 return inode->i_op->getattr(idmap, path, stat,
136 request_mask, query_flags);
137
138 generic_fillattr(idmap, request_mask, inode, stat);
139 return 0;
140}
141EXPORT_SYMBOL(vfs_getattr_nosec);
142
143/*
144 * vfs_getattr - Get the enhanced basic attributes of a file
145 * @path: The file of interest
146 * @stat: Where to return the statistics
147 * @request_mask: STATX_xxx flags indicating what the caller wants
148 * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
149 *
150 * Ask the filesystem for a file's attributes. The caller must indicate in
151 * request_mask and query_flags to indicate what they want.
152 *
153 * If the file is remote, the filesystem can be forced to update the attributes
154 * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
155 * suppress the update by passing AT_STATX_DONT_SYNC.
156 *
157 * Bits must have been set in request_mask to indicate which attributes the
158 * caller wants retrieving. Any such attribute not requested may be returned
159 * anyway, but the value may be approximate, and, if remote, may not have been
160 * synchronised with the server.
161 *
162 * 0 will be returned on success, and a -ve error code if unsuccessful.
163 */
164int vfs_getattr(const struct path *path, struct kstat *stat,
165 u32 request_mask, unsigned int query_flags)
166{
167 int retval;
168
169 retval = security_inode_getattr(path);
170 if (retval)
171 return retval;
172 return vfs_getattr_nosec(path, stat, request_mask, query_flags);
173}
174EXPORT_SYMBOL(vfs_getattr);
175
176/**
177 * vfs_fstat - Get the basic attributes by file descriptor
178 * @fd: The file descriptor referring to the file of interest
179 * @stat: The result structure to fill in.
180 *
181 * This function is a wrapper around vfs_getattr(). The main difference is
182 * that it uses a file descriptor to determine the file location.
183 *
184 * 0 will be returned on success, and a -ve error code if unsuccessful.
185 */
186int vfs_fstat(int fd, struct kstat *stat)
187{
188 struct fd f;
189 int error;
190
191 f = fdget_raw(fd);
192 if (!f.file)
193 return -EBADF;
194 error = vfs_getattr(&f.file->f_path, stat, STATX_BASIC_STATS, 0);
195 fdput(fd: f);
196 return error;
197}
198
199int getname_statx_lookup_flags(int flags)
200{
201 int lookup_flags = 0;
202
203 if (!(flags & AT_SYMLINK_NOFOLLOW))
204 lookup_flags |= LOOKUP_FOLLOW;
205 if (!(flags & AT_NO_AUTOMOUNT))
206 lookup_flags |= LOOKUP_AUTOMOUNT;
207 if (flags & AT_EMPTY_PATH)
208 lookup_flags |= LOOKUP_EMPTY;
209
210 return lookup_flags;
211}
212
213/**
214 * vfs_statx - Get basic and extra attributes by filename
215 * @dfd: A file descriptor representing the base dir for a relative filename
216 * @filename: The name of the file of interest
217 * @flags: Flags to control the query
218 * @stat: The result structure to fill in.
219 * @request_mask: STATX_xxx flags indicating what the caller wants
220 *
221 * This function is a wrapper around vfs_getattr(). The main difference is
222 * that it uses a filename and base directory to determine the file location.
223 * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
224 * at the given name from being referenced.
225 *
226 * 0 will be returned on success, and a -ve error code if unsuccessful.
227 */
228static int vfs_statx(int dfd, struct filename *filename, int flags,
229 struct kstat *stat, u32 request_mask)
230{
231 struct path path;
232 unsigned int lookup_flags = getname_statx_lookup_flags(flags);
233 int error;
234
235 if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
236 AT_STATX_SYNC_TYPE))
237 return -EINVAL;
238
239retry:
240 error = filename_lookup(dfd, name: filename, flags: lookup_flags, path: &path, NULL);
241 if (error)
242 goto out;
243
244 error = vfs_getattr(&path, stat, request_mask, flags);
245
246 stat->mnt_id = real_mount(mnt: path.mnt)->mnt_id;
247 stat->result_mask |= STATX_MNT_ID;
248
249 if (path.mnt->mnt_root == path.dentry)
250 stat->attributes |= STATX_ATTR_MOUNT_ROOT;
251 stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
252
253 /* Handle STATX_DIOALIGN for block devices. */
254 if (request_mask & STATX_DIOALIGN) {
255 struct inode *inode = d_backing_inode(upper: path.dentry);
256
257 if (S_ISBLK(inode->i_mode))
258 bdev_statx_dioalign(inode, stat);
259 }
260
261 path_put(&path);
262 if (retry_estale(error, flags: lookup_flags)) {
263 lookup_flags |= LOOKUP_REVAL;
264 goto retry;
265 }
266out:
267 return error;
268}
269
270int vfs_fstatat(int dfd, const char __user *filename,
271 struct kstat *stat, int flags)
272{
273 int ret;
274 int statx_flags = flags | AT_NO_AUTOMOUNT;
275 struct filename *name;
276
277 /*
278 * Work around glibc turning fstat() into fstatat(AT_EMPTY_PATH)
279 *
280 * If AT_EMPTY_PATH is set, we expect the common case to be that
281 * empty path, and avoid doing all the extra pathname work.
282 */
283 if (dfd >= 0 && flags == AT_EMPTY_PATH) {
284 char c;
285
286 ret = get_user(c, filename);
287 if (unlikely(ret))
288 return ret;
289
290 if (likely(!c))
291 return vfs_fstat(fd: dfd, stat);
292 }
293
294 name = getname_flags(filename, getname_statx_lookup_flags(flags: statx_flags), NULL);
295 ret = vfs_statx(dfd, filename: name, flags: statx_flags, stat, STATX_BASIC_STATS);
296 putname(name);
297
298 return ret;
299}
300
301#ifdef __ARCH_WANT_OLD_STAT
302
303/*
304 * For backward compatibility? Maybe this should be moved
305 * into arch/i386 instead?
306 */
307static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
308{
309 static int warncount = 5;
310 struct __old_kernel_stat tmp;
311
312 if (warncount > 0) {
313 warncount--;
314 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
315 current->comm);
316 } else if (warncount < 0) {
317 /* it's laughable, but... */
318 warncount = 0;
319 }
320
321 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
322 tmp.st_dev = old_encode_dev(dev: stat->dev);
323 tmp.st_ino = stat->ino;
324 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
325 return -EOVERFLOW;
326 tmp.st_mode = stat->mode;
327 tmp.st_nlink = stat->nlink;
328 if (tmp.st_nlink != stat->nlink)
329 return -EOVERFLOW;
330 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
331 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
332 tmp.st_rdev = old_encode_dev(dev: stat->rdev);
333#if BITS_PER_LONG == 32
334 if (stat->size > MAX_NON_LFS)
335 return -EOVERFLOW;
336#endif
337 tmp.st_size = stat->size;
338 tmp.st_atime = stat->atime.tv_sec;
339 tmp.st_mtime = stat->mtime.tv_sec;
340 tmp.st_ctime = stat->ctime.tv_sec;
341 return copy_to_user(to: statbuf,from: &tmp,n: sizeof(tmp)) ? -EFAULT : 0;
342}
343
344SYSCALL_DEFINE2(stat, const char __user *, filename,
345 struct __old_kernel_stat __user *, statbuf)
346{
347 struct kstat stat;
348 int error;
349
350 error = vfs_stat(filename, stat: &stat);
351 if (error)
352 return error;
353
354 return cp_old_stat(stat: &stat, statbuf);
355}
356
357SYSCALL_DEFINE2(lstat, const char __user *, filename,
358 struct __old_kernel_stat __user *, statbuf)
359{
360 struct kstat stat;
361 int error;
362
363 error = vfs_lstat(name: filename, stat: &stat);
364 if (error)
365 return error;
366
367 return cp_old_stat(stat: &stat, statbuf);
368}
369
370SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
371{
372 struct kstat stat;
373 int error = vfs_fstat(fd, stat: &stat);
374
375 if (!error)
376 error = cp_old_stat(stat: &stat, statbuf);
377
378 return error;
379}
380
381#endif /* __ARCH_WANT_OLD_STAT */
382
383#ifdef __ARCH_WANT_NEW_STAT
384
385#ifndef INIT_STRUCT_STAT_PADDING
386# define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
387#endif
388
389static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
390{
391 struct stat tmp;
392
393 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(dev: stat->dev))
394 return -EOVERFLOW;
395 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(dev: stat->rdev))
396 return -EOVERFLOW;
397#if BITS_PER_LONG == 32
398 if (stat->size > MAX_NON_LFS)
399 return -EOVERFLOW;
400#endif
401
402 INIT_STRUCT_STAT_PADDING(tmp);
403 tmp.st_dev = new_encode_dev(dev: stat->dev);
404 tmp.st_ino = stat->ino;
405 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
406 return -EOVERFLOW;
407 tmp.st_mode = stat->mode;
408 tmp.st_nlink = stat->nlink;
409 if (tmp.st_nlink != stat->nlink)
410 return -EOVERFLOW;
411 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
412 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
413 tmp.st_rdev = new_encode_dev(dev: stat->rdev);
414 tmp.st_size = stat->size;
415 tmp.st_atime = stat->atime.tv_sec;
416 tmp.st_mtime = stat->mtime.tv_sec;
417 tmp.st_ctime = stat->ctime.tv_sec;
418#ifdef STAT_HAVE_NSEC
419 tmp.st_atime_nsec = stat->atime.tv_nsec;
420 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
421 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
422#endif
423 tmp.st_blocks = stat->blocks;
424 tmp.st_blksize = stat->blksize;
425 return copy_to_user(to: statbuf,from: &tmp,n: sizeof(tmp)) ? -EFAULT : 0;
426}
427
428SYSCALL_DEFINE2(newstat, const char __user *, filename,
429 struct stat __user *, statbuf)
430{
431 struct kstat stat;
432 int error = vfs_stat(filename, stat: &stat);
433
434 if (error)
435 return error;
436 return cp_new_stat(stat: &stat, statbuf);
437}
438
439SYSCALL_DEFINE2(newlstat, const char __user *, filename,
440 struct stat __user *, statbuf)
441{
442 struct kstat stat;
443 int error;
444
445 error = vfs_lstat(name: filename, stat: &stat);
446 if (error)
447 return error;
448
449 return cp_new_stat(stat: &stat, statbuf);
450}
451
452#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
453SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
454 struct stat __user *, statbuf, int, flag)
455{
456 struct kstat stat;
457 int error;
458
459 error = vfs_fstatat(dfd, filename, stat: &stat, flags: flag);
460 if (error)
461 return error;
462 return cp_new_stat(stat: &stat, statbuf);
463}
464#endif
465
466SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
467{
468 struct kstat stat;
469 int error = vfs_fstat(fd, stat: &stat);
470
471 if (!error)
472 error = cp_new_stat(stat: &stat, statbuf);
473
474 return error;
475}
476#endif
477
478static int do_readlinkat(int dfd, const char __user *pathname,
479 char __user *buf, int bufsiz)
480{
481 struct path path;
482 int error;
483 int empty = 0;
484 unsigned int lookup_flags = LOOKUP_EMPTY;
485
486 if (bufsiz <= 0)
487 return -EINVAL;
488
489retry:
490 error = user_path_at_empty(dfd, pathname, lookup_flags, &path, empty: &empty);
491 if (!error) {
492 struct inode *inode = d_backing_inode(upper: path.dentry);
493
494 error = empty ? -ENOENT : -EINVAL;
495 /*
496 * AFS mountpoints allow readlink(2) but are not symlinks
497 */
498 if (d_is_symlink(dentry: path.dentry) || inode->i_op->readlink) {
499 error = security_inode_readlink(dentry: path.dentry);
500 if (!error) {
501 touch_atime(&path);
502 error = vfs_readlink(path.dentry, buf, bufsiz);
503 }
504 }
505 path_put(&path);
506 if (retry_estale(error, flags: lookup_flags)) {
507 lookup_flags |= LOOKUP_REVAL;
508 goto retry;
509 }
510 }
511 return error;
512}
513
514SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
515 char __user *, buf, int, bufsiz)
516{
517 return do_readlinkat(dfd, pathname, buf, bufsiz);
518}
519
520SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
521 int, bufsiz)
522{
523 return do_readlinkat(AT_FDCWD, pathname: path, buf, bufsiz);
524}
525
526
527/* ---------- LFS-64 ----------- */
528#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
529
530#ifndef INIT_STRUCT_STAT64_PADDING
531# define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
532#endif
533
534static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
535{
536 struct stat64 tmp;
537
538 INIT_STRUCT_STAT64_PADDING(tmp);
539#ifdef CONFIG_MIPS
540 /* mips has weird padding, so we don't get 64 bits there */
541 tmp.st_dev = new_encode_dev(stat->dev);
542 tmp.st_rdev = new_encode_dev(stat->rdev);
543#else
544 tmp.st_dev = huge_encode_dev(stat->dev);
545 tmp.st_rdev = huge_encode_dev(stat->rdev);
546#endif
547 tmp.st_ino = stat->ino;
548 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
549 return -EOVERFLOW;
550#ifdef STAT64_HAS_BROKEN_ST_INO
551 tmp.__st_ino = stat->ino;
552#endif
553 tmp.st_mode = stat->mode;
554 tmp.st_nlink = stat->nlink;
555 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
556 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
557 tmp.st_atime = stat->atime.tv_sec;
558 tmp.st_atime_nsec = stat->atime.tv_nsec;
559 tmp.st_mtime = stat->mtime.tv_sec;
560 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
561 tmp.st_ctime = stat->ctime.tv_sec;
562 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
563 tmp.st_size = stat->size;
564 tmp.st_blocks = stat->blocks;
565 tmp.st_blksize = stat->blksize;
566 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
567}
568
569SYSCALL_DEFINE2(stat64, const char __user *, filename,
570 struct stat64 __user *, statbuf)
571{
572 struct kstat stat;
573 int error = vfs_stat(filename, &stat);
574
575 if (!error)
576 error = cp_new_stat64(&stat, statbuf);
577
578 return error;
579}
580
581SYSCALL_DEFINE2(lstat64, const char __user *, filename,
582 struct stat64 __user *, statbuf)
583{
584 struct kstat stat;
585 int error = vfs_lstat(filename, &stat);
586
587 if (!error)
588 error = cp_new_stat64(&stat, statbuf);
589
590 return error;
591}
592
593SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
594{
595 struct kstat stat;
596 int error = vfs_fstat(fd, &stat);
597
598 if (!error)
599 error = cp_new_stat64(&stat, statbuf);
600
601 return error;
602}
603
604SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
605 struct stat64 __user *, statbuf, int, flag)
606{
607 struct kstat stat;
608 int error;
609
610 error = vfs_fstatat(dfd, filename, &stat, flag);
611 if (error)
612 return error;
613 return cp_new_stat64(&stat, statbuf);
614}
615#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
616
617static noinline_for_stack int
618cp_statx(const struct kstat *stat, struct statx __user *buffer)
619{
620 struct statx tmp;
621
622 memset(&tmp, 0, sizeof(tmp));
623
624 /* STATX_CHANGE_COOKIE is kernel-only for now */
625 tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE;
626 tmp.stx_blksize = stat->blksize;
627 /* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */
628 tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC;
629 tmp.stx_nlink = stat->nlink;
630 tmp.stx_uid = from_kuid_munged(current_user_ns(), uid: stat->uid);
631 tmp.stx_gid = from_kgid_munged(current_user_ns(), gid: stat->gid);
632 tmp.stx_mode = stat->mode;
633 tmp.stx_ino = stat->ino;
634 tmp.stx_size = stat->size;
635 tmp.stx_blocks = stat->blocks;
636 tmp.stx_attributes_mask = stat->attributes_mask;
637 tmp.stx_atime.tv_sec = stat->atime.tv_sec;
638 tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
639 tmp.stx_btime.tv_sec = stat->btime.tv_sec;
640 tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
641 tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
642 tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
643 tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
644 tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
645 tmp.stx_rdev_major = MAJOR(stat->rdev);
646 tmp.stx_rdev_minor = MINOR(stat->rdev);
647 tmp.stx_dev_major = MAJOR(stat->dev);
648 tmp.stx_dev_minor = MINOR(stat->dev);
649 tmp.stx_mnt_id = stat->mnt_id;
650 tmp.stx_dio_mem_align = stat->dio_mem_align;
651 tmp.stx_dio_offset_align = stat->dio_offset_align;
652
653 return copy_to_user(to: buffer, from: &tmp, n: sizeof(tmp)) ? -EFAULT : 0;
654}
655
656int do_statx(int dfd, struct filename *filename, unsigned int flags,
657 unsigned int mask, struct statx __user *buffer)
658{
659 struct kstat stat;
660 int error;
661
662 if (mask & STATX__RESERVED)
663 return -EINVAL;
664 if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
665 return -EINVAL;
666
667 /* STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
668 * from userland.
669 */
670 mask &= ~STATX_CHANGE_COOKIE;
671
672 error = vfs_statx(dfd, filename, flags, stat: &stat, request_mask: mask);
673 if (error)
674 return error;
675
676 return cp_statx(stat: &stat, buffer);
677}
678
679/**
680 * sys_statx - System call to get enhanced stats
681 * @dfd: Base directory to pathwalk from *or* fd to stat.
682 * @filename: File to stat or "" with AT_EMPTY_PATH
683 * @flags: AT_* flags to control pathwalk.
684 * @mask: Parts of statx struct actually required.
685 * @buffer: Result buffer.
686 *
687 * Note that fstat() can be emulated by setting dfd to the fd of interest,
688 * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
689 */
690SYSCALL_DEFINE5(statx,
691 int, dfd, const char __user *, filename, unsigned, flags,
692 unsigned int, mask,
693 struct statx __user *, buffer)
694{
695 int ret;
696 struct filename *name;
697
698 name = getname_flags(filename, getname_statx_lookup_flags(flags), NULL);
699 ret = do_statx(dfd, filename: name, flags, mask, buffer);
700 putname(name);
701
702 return ret;
703}
704
705#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
706static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
707{
708 struct compat_stat tmp;
709
710 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(dev: stat->dev))
711 return -EOVERFLOW;
712 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(dev: stat->rdev))
713 return -EOVERFLOW;
714
715 memset(&tmp, 0, sizeof(tmp));
716 tmp.st_dev = new_encode_dev(dev: stat->dev);
717 tmp.st_ino = stat->ino;
718 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
719 return -EOVERFLOW;
720 tmp.st_mode = stat->mode;
721 tmp.st_nlink = stat->nlink;
722 if (tmp.st_nlink != stat->nlink)
723 return -EOVERFLOW;
724 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
725 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
726 tmp.st_rdev = new_encode_dev(dev: stat->rdev);
727 if ((u64) stat->size > MAX_NON_LFS)
728 return -EOVERFLOW;
729 tmp.st_size = stat->size;
730 tmp.st_atime = stat->atime.tv_sec;
731 tmp.st_atime_nsec = stat->atime.tv_nsec;
732 tmp.st_mtime = stat->mtime.tv_sec;
733 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
734 tmp.st_ctime = stat->ctime.tv_sec;
735 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
736 tmp.st_blocks = stat->blocks;
737 tmp.st_blksize = stat->blksize;
738 return copy_to_user(to: ubuf, from: &tmp, n: sizeof(tmp)) ? -EFAULT : 0;
739}
740
741COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
742 struct compat_stat __user *, statbuf)
743{
744 struct kstat stat;
745 int error;
746
747 error = vfs_stat(filename, stat: &stat);
748 if (error)
749 return error;
750 return cp_compat_stat(stat: &stat, ubuf: statbuf);
751}
752
753COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
754 struct compat_stat __user *, statbuf)
755{
756 struct kstat stat;
757 int error;
758
759 error = vfs_lstat(name: filename, stat: &stat);
760 if (error)
761 return error;
762 return cp_compat_stat(stat: &stat, ubuf: statbuf);
763}
764
765#ifndef __ARCH_WANT_STAT64
766COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
767 const char __user *, filename,
768 struct compat_stat __user *, statbuf, int, flag)
769{
770 struct kstat stat;
771 int error;
772
773 error = vfs_fstatat(dfd, filename, stat: &stat, flags: flag);
774 if (error)
775 return error;
776 return cp_compat_stat(stat: &stat, ubuf: statbuf);
777}
778#endif
779
780COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
781 struct compat_stat __user *, statbuf)
782{
783 struct kstat stat;
784 int error = vfs_fstat(fd, stat: &stat);
785
786 if (!error)
787 error = cp_compat_stat(stat: &stat, ubuf: statbuf);
788 return error;
789}
790#endif
791
792/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
793void __inode_add_bytes(struct inode *inode, loff_t bytes)
794{
795 inode->i_blocks += bytes >> 9;
796 bytes &= 511;
797 inode->i_bytes += bytes;
798 if (inode->i_bytes >= 512) {
799 inode->i_blocks++;
800 inode->i_bytes -= 512;
801 }
802}
803EXPORT_SYMBOL(__inode_add_bytes);
804
805void inode_add_bytes(struct inode *inode, loff_t bytes)
806{
807 spin_lock(lock: &inode->i_lock);
808 __inode_add_bytes(inode, bytes);
809 spin_unlock(lock: &inode->i_lock);
810}
811
812EXPORT_SYMBOL(inode_add_bytes);
813
814void __inode_sub_bytes(struct inode *inode, loff_t bytes)
815{
816 inode->i_blocks -= bytes >> 9;
817 bytes &= 511;
818 if (inode->i_bytes < bytes) {
819 inode->i_blocks--;
820 inode->i_bytes += 512;
821 }
822 inode->i_bytes -= bytes;
823}
824
825EXPORT_SYMBOL(__inode_sub_bytes);
826
827void inode_sub_bytes(struct inode *inode, loff_t bytes)
828{
829 spin_lock(lock: &inode->i_lock);
830 __inode_sub_bytes(inode, bytes);
831 spin_unlock(lock: &inode->i_lock);
832}
833
834EXPORT_SYMBOL(inode_sub_bytes);
835
836loff_t inode_get_bytes(struct inode *inode)
837{
838 loff_t ret;
839
840 spin_lock(lock: &inode->i_lock);
841 ret = __inode_get_bytes(inode);
842 spin_unlock(lock: &inode->i_lock);
843 return ret;
844}
845
846EXPORT_SYMBOL(inode_get_bytes);
847
848void inode_set_bytes(struct inode *inode, loff_t bytes)
849{
850 /* Caller is here responsible for sufficient locking
851 * (ie. inode->i_lock) */
852 inode->i_blocks = bytes >> 9;
853 inode->i_bytes = bytes & 511;
854}
855
856EXPORT_SYMBOL(inode_set_bytes);
857

source code of linux/fs/stat.c