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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
22#include <linux/uaccess.h>
23#include <asm/unistd.h>
24
25#include "internal.h"
26#include "mount.h"
27
28/**
29 * generic_fillattr - Fill in the basic attributes from the inode struct
30 * @mnt_userns: user namespace of the mount the inode was found from
31 * @inode: Inode to use as the source
32 * @stat: Where to fill in the attributes
33 *
34 * Fill in the basic attributes in the kstat structure from data that's to be
35 * found on the VFS inode structure. This is the default if no getattr inode
36 * operation is supplied.
37 *
38 * If the inode has been found through an idmapped mount the user namespace of
39 * the vfsmount must be passed through @mnt_userns. This function will then
40 * take care to map the inode according to @mnt_userns before filling in the
41 * uid and gid filds. On non-idmapped mounts or if permission checking is to be
42 * performed on the raw inode simply passs init_user_ns.
43 */
44void generic_fillattr(struct user_namespace *mnt_userns, struct inode *inode,
45 struct kstat *stat)
46{
47 vfsuid_t vfsuid = i_uid_into_vfsuid(mnt_userns, inode);
48 vfsgid_t vfsgid = i_gid_into_vfsgid(mnt_userns, inode);
49
50 stat->dev = inode->i_sb->s_dev;
51 stat->ino = inode->i_ino;
52 stat->mode = inode->i_mode;
53 stat->nlink = inode->i_nlink;
54 stat->uid = vfsuid_into_kuid(vfsuid);
55 stat->gid = vfsgid_into_kgid(vfsgid);
56 stat->rdev = inode->i_rdev;
57 stat->size = i_size_read(inode);
58 stat->atime = inode->i_atime;
59 stat->mtime = inode->i_mtime;
60 stat->ctime = inode->i_ctime;
61 stat->blksize = i_blocksize(inode);
62 stat->blocks = inode->i_blocks;
63}
64EXPORT_SYMBOL(generic_fillattr);
65
66/**
67 * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
68 * @inode: Inode to use as the source
69 * @stat: Where to fill in the attribute flags
70 *
71 * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
72 * inode that are published on i_flags and enforced by the VFS.
73 */
74void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
75{
76 if (inode->i_flags & S_IMMUTABLE)
77 stat->attributes |= STATX_ATTR_IMMUTABLE;
78 if (inode->i_flags & S_APPEND)
79 stat->attributes |= STATX_ATTR_APPEND;
80 stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
81}
82EXPORT_SYMBOL(generic_fill_statx_attr);
83
84/**
85 * vfs_getattr_nosec - getattr without security checks
86 * @path: file to get attributes from
87 * @stat: structure to return attributes in
88 * @request_mask: STATX_xxx flags indicating what the caller wants
89 * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
90 *
91 * Get attributes without calling security_inode_getattr.
92 *
93 * Currently the only caller other than vfs_getattr is internal to the
94 * filehandle lookup code, which uses only the inode number and returns no
95 * attributes to any user. Any other code probably wants vfs_getattr.
96 */
97int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
98 u32 request_mask, unsigned int query_flags)
99{
100 struct user_namespace *mnt_userns;
101 struct inode *inode = d_backing_inode(path->dentry);
102
103 memset(stat, 0, sizeof(*stat));
104 stat->result_mask |= STATX_BASIC_STATS;
105 query_flags &= AT_STATX_SYNC_TYPE;
106
107 /* allow the fs to override these if it really wants to */
108 /* SB_NOATIME means filesystem supplies dummy atime value */
109 if (inode->i_sb->s_flags & SB_NOATIME)
110 stat->result_mask &= ~STATX_ATIME;
111
112 /*
113 * Note: If you add another clause to set an attribute flag, please
114 * update attributes_mask below.
115 */
116 if (IS_AUTOMOUNT(inode))
117 stat->attributes |= STATX_ATTR_AUTOMOUNT;
118
119 if (IS_DAX(inode))
120 stat->attributes |= STATX_ATTR_DAX;
121
122 stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
123 STATX_ATTR_DAX);
124
125 mnt_userns = mnt_user_ns(path->mnt);
126 if (inode->i_op->getattr)
127 return inode->i_op->getattr(mnt_userns, path, stat,
128 request_mask, query_flags);
129
130 generic_fillattr(mnt_userns, inode, stat);
131 return 0;
132}
133EXPORT_SYMBOL(vfs_getattr_nosec);
134
135/*
136 * vfs_getattr - Get the enhanced basic attributes of a file
137 * @path: The file of interest
138 * @stat: Where to return the statistics
139 * @request_mask: STATX_xxx flags indicating what the caller wants
140 * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
141 *
142 * Ask the filesystem for a file's attributes. The caller must indicate in
143 * request_mask and query_flags to indicate what they want.
144 *
145 * If the file is remote, the filesystem can be forced to update the attributes
146 * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
147 * suppress the update by passing AT_STATX_DONT_SYNC.
148 *
149 * Bits must have been set in request_mask to indicate which attributes the
150 * caller wants retrieving. Any such attribute not requested may be returned
151 * anyway, but the value may be approximate, and, if remote, may not have been
152 * synchronised with the server.
153 *
154 * 0 will be returned on success, and a -ve error code if unsuccessful.
155 */
156int vfs_getattr(const struct path *path, struct kstat *stat,
157 u32 request_mask, unsigned int query_flags)
158{
159 int retval;
160
161 retval = security_inode_getattr(path);
162 if (retval)
163 return retval;
164 return vfs_getattr_nosec(path, stat, request_mask, query_flags);
165}
166EXPORT_SYMBOL(vfs_getattr);
167
168/**
169 * vfs_fstat - Get the basic attributes by file descriptor
170 * @fd: The file descriptor referring to the file of interest
171 * @stat: The result structure to fill in.
172 *
173 * This function is a wrapper around vfs_getattr(). The main difference is
174 * that it uses a file descriptor to determine the file location.
175 *
176 * 0 will be returned on success, and a -ve error code if unsuccessful.
177 */
178int vfs_fstat(int fd, struct kstat *stat)
179{
180 struct fd f;
181 int error;
182
183 f = fdget_raw(fd);
184 if (!f.file)
185 return -EBADF;
186 error = vfs_getattr(&f.file->f_path, stat, STATX_BASIC_STATS, 0);
187 fdput(f);
188 return error;
189}
190
191int getname_statx_lookup_flags(int flags)
192{
193 int lookup_flags = 0;
194
195 if (!(flags & AT_SYMLINK_NOFOLLOW))
196 lookup_flags |= LOOKUP_FOLLOW;
197 if (!(flags & AT_NO_AUTOMOUNT))
198 lookup_flags |= LOOKUP_AUTOMOUNT;
199 if (flags & AT_EMPTY_PATH)
200 lookup_flags |= LOOKUP_EMPTY;
201
202 return lookup_flags;
203}
204
205/**
206 * vfs_statx - Get basic and extra attributes by filename
207 * @dfd: A file descriptor representing the base dir for a relative filename
208 * @filename: The name of the file of interest
209 * @flags: Flags to control the query
210 * @stat: The result structure to fill in.
211 * @request_mask: STATX_xxx flags indicating what the caller wants
212 *
213 * This function is a wrapper around vfs_getattr(). The main difference is
214 * that it uses a filename and base directory to determine the file location.
215 * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
216 * at the given name from being referenced.
217 *
218 * 0 will be returned on success, and a -ve error code if unsuccessful.
219 */
220static int vfs_statx(int dfd, struct filename *filename, int flags,
221 struct kstat *stat, u32 request_mask)
222{
223 struct path path;
224 unsigned int lookup_flags = getname_statx_lookup_flags(flags);
225 int error;
226
227 if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
228 AT_STATX_SYNC_TYPE))
229 return -EINVAL;
230
231retry:
232 error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
233 if (error)
234 goto out;
235
236 error = vfs_getattr(&path, stat, request_mask, flags);
237
238 stat->mnt_id = real_mount(path.mnt)->mnt_id;
239 stat->result_mask |= STATX_MNT_ID;
240
241 if (path.mnt->mnt_root == path.dentry)
242 stat->attributes |= STATX_ATTR_MOUNT_ROOT;
243 stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
244
245 /* Handle STATX_DIOALIGN for block devices. */
246 if (request_mask & STATX_DIOALIGN) {
247 struct inode *inode = d_backing_inode(path.dentry);
248
249 if (S_ISBLK(inode->i_mode))
250 bdev_statx_dioalign(inode, stat);
251 }
252
253 path_put(&path);
254 if (retry_estale(error, lookup_flags)) {
255 lookup_flags |= LOOKUP_REVAL;
256 goto retry;
257 }
258out:
259 return error;
260}
261
262int vfs_fstatat(int dfd, const char __user *filename,
263 struct kstat *stat, int flags)
264{
265 int ret;
266 int statx_flags = flags | AT_NO_AUTOMOUNT;
267 struct filename *name;
268
269 name = getname_flags(filename, getname_statx_lookup_flags(statx_flags), NULL);
270 ret = vfs_statx(dfd, name, statx_flags, stat, STATX_BASIC_STATS);
271 putname(name);
272
273 return ret;
274}
275
276#ifdef __ARCH_WANT_OLD_STAT
277
278/*
279 * For backward compatibility? Maybe this should be moved
280 * into arch/i386 instead?
281 */
282static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
283{
284 static int warncount = 5;
285 struct __old_kernel_stat tmp;
286
287 if (warncount > 0) {
288 warncount--;
289 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
290 current->comm);
291 } else if (warncount < 0) {
292 /* it's laughable, but... */
293 warncount = 0;
294 }
295
296 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
297 tmp.st_dev = old_encode_dev(stat->dev);
298 tmp.st_ino = stat->ino;
299 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
300 return -EOVERFLOW;
301 tmp.st_mode = stat->mode;
302 tmp.st_nlink = stat->nlink;
303 if (tmp.st_nlink != stat->nlink)
304 return -EOVERFLOW;
305 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
306 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
307 tmp.st_rdev = old_encode_dev(stat->rdev);
308#if BITS_PER_LONG == 32
309 if (stat->size > MAX_NON_LFS)
310 return -EOVERFLOW;
311#endif
312 tmp.st_size = stat->size;
313 tmp.st_atime = stat->atime.tv_sec;
314 tmp.st_mtime = stat->mtime.tv_sec;
315 tmp.st_ctime = stat->ctime.tv_sec;
316 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
317}
318
319SYSCALL_DEFINE2(stat, const char __user *, filename,
320 struct __old_kernel_stat __user *, statbuf)
321{
322 struct kstat stat;
323 int error;
324
325 error = vfs_stat(filename, &stat);
326 if (error)
327 return error;
328
329 return cp_old_stat(&stat, statbuf);
330}
331
332SYSCALL_DEFINE2(lstat, const char __user *, filename,
333 struct __old_kernel_stat __user *, statbuf)
334{
335 struct kstat stat;
336 int error;
337
338 error = vfs_lstat(filename, &stat);
339 if (error)
340 return error;
341
342 return cp_old_stat(&stat, statbuf);
343}
344
345SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
346{
347 struct kstat stat;
348 int error = vfs_fstat(fd, &stat);
349
350 if (!error)
351 error = cp_old_stat(&stat, statbuf);
352
353 return error;
354}
355
356#endif /* __ARCH_WANT_OLD_STAT */
357
358#ifdef __ARCH_WANT_NEW_STAT
359
360#if BITS_PER_LONG == 32
361# define choose_32_64(a,b) a
362#else
363# define choose_32_64(a,b) b
364#endif
365
366#ifndef INIT_STRUCT_STAT_PADDING
367# define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
368#endif
369
370static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
371{
372 struct stat tmp;
373
374 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
375 return -EOVERFLOW;
376 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
377 return -EOVERFLOW;
378#if BITS_PER_LONG == 32
379 if (stat->size > MAX_NON_LFS)
380 return -EOVERFLOW;
381#endif
382
383 INIT_STRUCT_STAT_PADDING(tmp);
384 tmp.st_dev = new_encode_dev(stat->dev);
385 tmp.st_ino = stat->ino;
386 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
387 return -EOVERFLOW;
388 tmp.st_mode = stat->mode;
389 tmp.st_nlink = stat->nlink;
390 if (tmp.st_nlink != stat->nlink)
391 return -EOVERFLOW;
392 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
393 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
394 tmp.st_rdev = new_encode_dev(stat->rdev);
395 tmp.st_size = stat->size;
396 tmp.st_atime = stat->atime.tv_sec;
397 tmp.st_mtime = stat->mtime.tv_sec;
398 tmp.st_ctime = stat->ctime.tv_sec;
399#ifdef STAT_HAVE_NSEC
400 tmp.st_atime_nsec = stat->atime.tv_nsec;
401 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
402 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
403#endif
404 tmp.st_blocks = stat->blocks;
405 tmp.st_blksize = stat->blksize;
406 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
407}
408
409SYSCALL_DEFINE2(newstat, const char __user *, filename,
410 struct stat __user *, statbuf)
411{
412 struct kstat stat;
413 int error = vfs_stat(filename, &stat);
414
415 if (error)
416 return error;
417 return cp_new_stat(&stat, statbuf);
418}
419
420SYSCALL_DEFINE2(newlstat, const char __user *, filename,
421 struct stat __user *, statbuf)
422{
423 struct kstat stat;
424 int error;
425
426 error = vfs_lstat(filename, &stat);
427 if (error)
428 return error;
429
430 return cp_new_stat(&stat, statbuf);
431}
432
433#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
434SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
435 struct stat __user *, statbuf, int, flag)
436{
437 struct kstat stat;
438 int error;
439
440 error = vfs_fstatat(dfd, filename, &stat, flag);
441 if (error)
442 return error;
443 return cp_new_stat(&stat, statbuf);
444}
445#endif
446
447SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
448{
449 struct kstat stat;
450 int error = vfs_fstat(fd, &stat);
451
452 if (!error)
453 error = cp_new_stat(&stat, statbuf);
454
455 return error;
456}
457#endif
458
459static int do_readlinkat(int dfd, const char __user *pathname,
460 char __user *buf, int bufsiz)
461{
462 struct path path;
463 int error;
464 int empty = 0;
465 unsigned int lookup_flags = LOOKUP_EMPTY;
466
467 if (bufsiz <= 0)
468 return -EINVAL;
469
470retry:
471 error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
472 if (!error) {
473 struct inode *inode = d_backing_inode(path.dentry);
474
475 error = empty ? -ENOENT : -EINVAL;
476 /*
477 * AFS mountpoints allow readlink(2) but are not symlinks
478 */
479 if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
480 error = security_inode_readlink(path.dentry);
481 if (!error) {
482 touch_atime(&path);
483 error = vfs_readlink(path.dentry, buf, bufsiz);
484 }
485 }
486 path_put(&path);
487 if (retry_estale(error, lookup_flags)) {
488 lookup_flags |= LOOKUP_REVAL;
489 goto retry;
490 }
491 }
492 return error;
493}
494
495SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
496 char __user *, buf, int, bufsiz)
497{
498 return do_readlinkat(dfd, pathname, buf, bufsiz);
499}
500
501SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
502 int, bufsiz)
503{
504 return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
505}
506
507
508/* ---------- LFS-64 ----------- */
509#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
510
511#ifndef INIT_STRUCT_STAT64_PADDING
512# define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
513#endif
514
515static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
516{
517 struct stat64 tmp;
518
519 INIT_STRUCT_STAT64_PADDING(tmp);
520#ifdef CONFIG_MIPS
521 /* mips has weird padding, so we don't get 64 bits there */
522 tmp.st_dev = new_encode_dev(stat->dev);
523 tmp.st_rdev = new_encode_dev(stat->rdev);
524#else
525 tmp.st_dev = huge_encode_dev(stat->dev);
526 tmp.st_rdev = huge_encode_dev(stat->rdev);
527#endif
528 tmp.st_ino = stat->ino;
529 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
530 return -EOVERFLOW;
531#ifdef STAT64_HAS_BROKEN_ST_INO
532 tmp.__st_ino = stat->ino;
533#endif
534 tmp.st_mode = stat->mode;
535 tmp.st_nlink = stat->nlink;
536 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
537 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
538 tmp.st_atime = stat->atime.tv_sec;
539 tmp.st_atime_nsec = stat->atime.tv_nsec;
540 tmp.st_mtime = stat->mtime.tv_sec;
541 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
542 tmp.st_ctime = stat->ctime.tv_sec;
543 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
544 tmp.st_size = stat->size;
545 tmp.st_blocks = stat->blocks;
546 tmp.st_blksize = stat->blksize;
547 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
548}
549
550SYSCALL_DEFINE2(stat64, const char __user *, filename,
551 struct stat64 __user *, statbuf)
552{
553 struct kstat stat;
554 int error = vfs_stat(filename, &stat);
555
556 if (!error)
557 error = cp_new_stat64(&stat, statbuf);
558
559 return error;
560}
561
562SYSCALL_DEFINE2(lstat64, const char __user *, filename,
563 struct stat64 __user *, statbuf)
564{
565 struct kstat stat;
566 int error = vfs_lstat(filename, &stat);
567
568 if (!error)
569 error = cp_new_stat64(&stat, statbuf);
570
571 return error;
572}
573
574SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
575{
576 struct kstat stat;
577 int error = vfs_fstat(fd, &stat);
578
579 if (!error)
580 error = cp_new_stat64(&stat, statbuf);
581
582 return error;
583}
584
585SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
586 struct stat64 __user *, statbuf, int, flag)
587{
588 struct kstat stat;
589 int error;
590
591 error = vfs_fstatat(dfd, filename, &stat, flag);
592 if (error)
593 return error;
594 return cp_new_stat64(&stat, statbuf);
595}
596#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
597
598static noinline_for_stack int
599cp_statx(const struct kstat *stat, struct statx __user *buffer)
600{
601 struct statx tmp;
602
603 memset(&tmp, 0, sizeof(tmp));
604
605 tmp.stx_mask = stat->result_mask;
606 tmp.stx_blksize = stat->blksize;
607 tmp.stx_attributes = stat->attributes;
608 tmp.stx_nlink = stat->nlink;
609 tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
610 tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
611 tmp.stx_mode = stat->mode;
612 tmp.stx_ino = stat->ino;
613 tmp.stx_size = stat->size;
614 tmp.stx_blocks = stat->blocks;
615 tmp.stx_attributes_mask = stat->attributes_mask;
616 tmp.stx_atime.tv_sec = stat->atime.tv_sec;
617 tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
618 tmp.stx_btime.tv_sec = stat->btime.tv_sec;
619 tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
620 tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
621 tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
622 tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
623 tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
624 tmp.stx_rdev_major = MAJOR(stat->rdev);
625 tmp.stx_rdev_minor = MINOR(stat->rdev);
626 tmp.stx_dev_major = MAJOR(stat->dev);
627 tmp.stx_dev_minor = MINOR(stat->dev);
628 tmp.stx_mnt_id = stat->mnt_id;
629 tmp.stx_dio_mem_align = stat->dio_mem_align;
630 tmp.stx_dio_offset_align = stat->dio_offset_align;
631
632 return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
633}
634
635int do_statx(int dfd, struct filename *filename, unsigned int flags,
636 unsigned int mask, struct statx __user *buffer)
637{
638 struct kstat stat;
639 int error;
640
641 if (mask & STATX__RESERVED)
642 return -EINVAL;
643 if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
644 return -EINVAL;
645
646 error = vfs_statx(dfd, filename, flags, &stat, mask);
647 if (error)
648 return error;
649
650 return cp_statx(&stat, buffer);
651}
652
653/**
654 * sys_statx - System call to get enhanced stats
655 * @dfd: Base directory to pathwalk from *or* fd to stat.
656 * @filename: File to stat or "" with AT_EMPTY_PATH
657 * @flags: AT_* flags to control pathwalk.
658 * @mask: Parts of statx struct actually required.
659 * @buffer: Result buffer.
660 *
661 * Note that fstat() can be emulated by setting dfd to the fd of interest,
662 * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
663 */
664SYSCALL_DEFINE5(statx,
665 int, dfd, const char __user *, filename, unsigned, flags,
666 unsigned int, mask,
667 struct statx __user *, buffer)
668{
669 int ret;
670 struct filename *name;
671
672 name = getname_flags(filename, getname_statx_lookup_flags(flags), NULL);
673 ret = do_statx(dfd, name, flags, mask, buffer);
674 putname(name);
675
676 return ret;
677}
678
679#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
680static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
681{
682 struct compat_stat tmp;
683
684 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
685 return -EOVERFLOW;
686 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
687 return -EOVERFLOW;
688
689 memset(&tmp, 0, sizeof(tmp));
690 tmp.st_dev = new_encode_dev(stat->dev);
691 tmp.st_ino = stat->ino;
692 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
693 return -EOVERFLOW;
694 tmp.st_mode = stat->mode;
695 tmp.st_nlink = stat->nlink;
696 if (tmp.st_nlink != stat->nlink)
697 return -EOVERFLOW;
698 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
699 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
700 tmp.st_rdev = new_encode_dev(stat->rdev);
701 if ((u64) stat->size > MAX_NON_LFS)
702 return -EOVERFLOW;
703 tmp.st_size = stat->size;
704 tmp.st_atime = stat->atime.tv_sec;
705 tmp.st_atime_nsec = stat->atime.tv_nsec;
706 tmp.st_mtime = stat->mtime.tv_sec;
707 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
708 tmp.st_ctime = stat->ctime.tv_sec;
709 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
710 tmp.st_blocks = stat->blocks;
711 tmp.st_blksize = stat->blksize;
712 return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
713}
714
715COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
716 struct compat_stat __user *, statbuf)
717{
718 struct kstat stat;
719 int error;
720
721 error = vfs_stat(filename, &stat);
722 if (error)
723 return error;
724 return cp_compat_stat(&stat, statbuf);
725}
726
727COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
728 struct compat_stat __user *, statbuf)
729{
730 struct kstat stat;
731 int error;
732
733 error = vfs_lstat(filename, &stat);
734 if (error)
735 return error;
736 return cp_compat_stat(&stat, statbuf);
737}
738
739#ifndef __ARCH_WANT_STAT64
740COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
741 const char __user *, filename,
742 struct compat_stat __user *, statbuf, int, flag)
743{
744 struct kstat stat;
745 int error;
746
747 error = vfs_fstatat(dfd, filename, &stat, flag);
748 if (error)
749 return error;
750 return cp_compat_stat(&stat, statbuf);
751}
752#endif
753
754COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
755 struct compat_stat __user *, statbuf)
756{
757 struct kstat stat;
758 int error = vfs_fstat(fd, &stat);
759
760 if (!error)
761 error = cp_compat_stat(&stat, statbuf);
762 return error;
763}
764#endif
765
766/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
767void __inode_add_bytes(struct inode *inode, loff_t bytes)
768{
769 inode->i_blocks += bytes >> 9;
770 bytes &= 511;
771 inode->i_bytes += bytes;
772 if (inode->i_bytes >= 512) {
773 inode->i_blocks++;
774 inode->i_bytes -= 512;
775 }
776}
777EXPORT_SYMBOL(__inode_add_bytes);
778
779void inode_add_bytes(struct inode *inode, loff_t bytes)
780{
781 spin_lock(&inode->i_lock);
782 __inode_add_bytes(inode, bytes);
783 spin_unlock(&inode->i_lock);
784}
785
786EXPORT_SYMBOL(inode_add_bytes);
787
788void __inode_sub_bytes(struct inode *inode, loff_t bytes)
789{
790 inode->i_blocks -= bytes >> 9;
791 bytes &= 511;
792 if (inode->i_bytes < bytes) {
793 inode->i_blocks--;
794 inode->i_bytes += 512;
795 }
796 inode->i_bytes -= bytes;
797}
798
799EXPORT_SYMBOL(__inode_sub_bytes);
800
801void inode_sub_bytes(struct inode *inode, loff_t bytes)
802{
803 spin_lock(&inode->i_lock);
804 __inode_sub_bytes(inode, bytes);
805 spin_unlock(&inode->i_lock);
806}
807
808EXPORT_SYMBOL(inode_sub_bytes);
809
810loff_t inode_get_bytes(struct inode *inode)
811{
812 loff_t ret;
813
814 spin_lock(&inode->i_lock);
815 ret = __inode_get_bytes(inode);
816 spin_unlock(&inode->i_lock);
817 return ret;
818}
819
820EXPORT_SYMBOL(inode_get_bytes);
821
822void inode_set_bytes(struct inode *inode, loff_t bytes)
823{
824 /* Caller is here responsible for sufficient locking
825 * (ie. inode->i_lock) */
826 inode->i_blocks = bytes >> 9;
827 inode->i_bytes = bytes & 511;
828}
829
830EXPORT_SYMBOL(inode_set_bytes);
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 pass @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(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(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(path->mnt);
134 if (inode->i_op->getattr)
135 return inode->i_op->getattr(idmap, path, stat,
136 request_mask,
137 query_flags | AT_GETATTR_NOSEC);
138
139 generic_fillattr(idmap, request_mask, inode, stat);
140 return 0;
141}
142EXPORT_SYMBOL(vfs_getattr_nosec);
143
144/*
145 * vfs_getattr - Get the enhanced basic attributes of a file
146 * @path: The file of interest
147 * @stat: Where to return the statistics
148 * @request_mask: STATX_xxx flags indicating what the caller wants
149 * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
150 *
151 * Ask the filesystem for a file's attributes. The caller must indicate in
152 * request_mask and query_flags to indicate what they want.
153 *
154 * If the file is remote, the filesystem can be forced to update the attributes
155 * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
156 * suppress the update by passing AT_STATX_DONT_SYNC.
157 *
158 * Bits must have been set in request_mask to indicate which attributes the
159 * caller wants retrieving. Any such attribute not requested may be returned
160 * anyway, but the value may be approximate, and, if remote, may not have been
161 * synchronised with the server.
162 *
163 * 0 will be returned on success, and a -ve error code if unsuccessful.
164 */
165int vfs_getattr(const struct path *path, struct kstat *stat,
166 u32 request_mask, unsigned int query_flags)
167{
168 int retval;
169
170 if (WARN_ON_ONCE(query_flags & AT_GETATTR_NOSEC))
171 return -EPERM;
172
173 retval = security_inode_getattr(path);
174 if (retval)
175 return retval;
176 return vfs_getattr_nosec(path, stat, request_mask, query_flags);
177}
178EXPORT_SYMBOL(vfs_getattr);
179
180/**
181 * vfs_fstat - Get the basic attributes by file descriptor
182 * @fd: The file descriptor referring to the file of interest
183 * @stat: The result structure to fill in.
184 *
185 * This function is a wrapper around vfs_getattr(). The main difference is
186 * that it uses a file descriptor to determine the file location.
187 *
188 * 0 will be returned on success, and a -ve error code if unsuccessful.
189 */
190int vfs_fstat(int fd, struct kstat *stat)
191{
192 struct fd f;
193 int error;
194
195 f = fdget_raw(fd);
196 if (!f.file)
197 return -EBADF;
198 error = vfs_getattr(&f.file->f_path, stat, STATX_BASIC_STATS, 0);
199 fdput(f);
200 return error;
201}
202
203int getname_statx_lookup_flags(int flags)
204{
205 int lookup_flags = 0;
206
207 if (!(flags & AT_SYMLINK_NOFOLLOW))
208 lookup_flags |= LOOKUP_FOLLOW;
209 if (!(flags & AT_NO_AUTOMOUNT))
210 lookup_flags |= LOOKUP_AUTOMOUNT;
211 if (flags & AT_EMPTY_PATH)
212 lookup_flags |= LOOKUP_EMPTY;
213
214 return lookup_flags;
215}
216
217/**
218 * vfs_statx - Get basic and extra attributes by filename
219 * @dfd: A file descriptor representing the base dir for a relative filename
220 * @filename: The name of the file of interest
221 * @flags: Flags to control the query
222 * @stat: The result structure to fill in.
223 * @request_mask: STATX_xxx flags indicating what the caller wants
224 *
225 * This function is a wrapper around vfs_getattr(). The main difference is
226 * that it uses a filename and base directory to determine the file location.
227 * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
228 * at the given name from being referenced.
229 *
230 * 0 will be returned on success, and a -ve error code if unsuccessful.
231 */
232static int vfs_statx(int dfd, struct filename *filename, int flags,
233 struct kstat *stat, u32 request_mask)
234{
235 struct path path;
236 unsigned int lookup_flags = getname_statx_lookup_flags(flags);
237 int error;
238
239 if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
240 AT_STATX_SYNC_TYPE))
241 return -EINVAL;
242
243retry:
244 error = filename_lookup(dfd, filename, lookup_flags, &path, NULL);
245 if (error)
246 goto out;
247
248 error = vfs_getattr(&path, stat, request_mask, flags);
249
250 if (request_mask & STATX_MNT_ID_UNIQUE) {
251 stat->mnt_id = real_mount(path.mnt)->mnt_id_unique;
252 stat->result_mask |= STATX_MNT_ID_UNIQUE;
253 } else {
254 stat->mnt_id = real_mount(path.mnt)->mnt_id;
255 stat->result_mask |= STATX_MNT_ID;
256 }
257
258 if (path.mnt->mnt_root == path.dentry)
259 stat->attributes |= STATX_ATTR_MOUNT_ROOT;
260 stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
261
262 /* Handle STATX_DIOALIGN for block devices. */
263 if (request_mask & STATX_DIOALIGN) {
264 struct inode *inode = d_backing_inode(path.dentry);
265
266 if (S_ISBLK(inode->i_mode))
267 bdev_statx_dioalign(inode, stat);
268 }
269
270 path_put(&path);
271 if (retry_estale(error, lookup_flags)) {
272 lookup_flags |= LOOKUP_REVAL;
273 goto retry;
274 }
275out:
276 return error;
277}
278
279int vfs_fstatat(int dfd, const char __user *filename,
280 struct kstat *stat, int flags)
281{
282 int ret;
283 int statx_flags = flags | AT_NO_AUTOMOUNT;
284 struct filename *name;
285
286 /*
287 * Work around glibc turning fstat() into fstatat(AT_EMPTY_PATH)
288 *
289 * If AT_EMPTY_PATH is set, we expect the common case to be that
290 * empty path, and avoid doing all the extra pathname work.
291 */
292 if (dfd >= 0 && flags == AT_EMPTY_PATH) {
293 char c;
294
295 ret = get_user(c, filename);
296 if (unlikely(ret))
297 return ret;
298
299 if (likely(!c))
300 return vfs_fstat(dfd, stat);
301 }
302
303 name = getname_flags(filename, getname_statx_lookup_flags(statx_flags), NULL);
304 ret = vfs_statx(dfd, name, statx_flags, stat, STATX_BASIC_STATS);
305 putname(name);
306
307 return ret;
308}
309
310#ifdef __ARCH_WANT_OLD_STAT
311
312/*
313 * For backward compatibility? Maybe this should be moved
314 * into arch/i386 instead?
315 */
316static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
317{
318 static int warncount = 5;
319 struct __old_kernel_stat tmp;
320
321 if (warncount > 0) {
322 warncount--;
323 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
324 current->comm);
325 } else if (warncount < 0) {
326 /* it's laughable, but... */
327 warncount = 0;
328 }
329
330 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
331 tmp.st_dev = old_encode_dev(stat->dev);
332 tmp.st_ino = stat->ino;
333 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
334 return -EOVERFLOW;
335 tmp.st_mode = stat->mode;
336 tmp.st_nlink = stat->nlink;
337 if (tmp.st_nlink != stat->nlink)
338 return -EOVERFLOW;
339 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
340 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
341 tmp.st_rdev = old_encode_dev(stat->rdev);
342#if BITS_PER_LONG == 32
343 if (stat->size > MAX_NON_LFS)
344 return -EOVERFLOW;
345#endif
346 tmp.st_size = stat->size;
347 tmp.st_atime = stat->atime.tv_sec;
348 tmp.st_mtime = stat->mtime.tv_sec;
349 tmp.st_ctime = stat->ctime.tv_sec;
350 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
351}
352
353SYSCALL_DEFINE2(stat, const char __user *, filename,
354 struct __old_kernel_stat __user *, statbuf)
355{
356 struct kstat stat;
357 int error;
358
359 error = vfs_stat(filename, &stat);
360 if (error)
361 return error;
362
363 return cp_old_stat(&stat, statbuf);
364}
365
366SYSCALL_DEFINE2(lstat, const char __user *, filename,
367 struct __old_kernel_stat __user *, statbuf)
368{
369 struct kstat stat;
370 int error;
371
372 error = vfs_lstat(filename, &stat);
373 if (error)
374 return error;
375
376 return cp_old_stat(&stat, statbuf);
377}
378
379SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
380{
381 struct kstat stat;
382 int error = vfs_fstat(fd, &stat);
383
384 if (!error)
385 error = cp_old_stat(&stat, statbuf);
386
387 return error;
388}
389
390#endif /* __ARCH_WANT_OLD_STAT */
391
392#ifdef __ARCH_WANT_NEW_STAT
393
394#ifndef INIT_STRUCT_STAT_PADDING
395# define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
396#endif
397
398static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
399{
400 struct stat tmp;
401
402 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
403 return -EOVERFLOW;
404 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
405 return -EOVERFLOW;
406#if BITS_PER_LONG == 32
407 if (stat->size > MAX_NON_LFS)
408 return -EOVERFLOW;
409#endif
410
411 INIT_STRUCT_STAT_PADDING(tmp);
412 tmp.st_dev = new_encode_dev(stat->dev);
413 tmp.st_ino = stat->ino;
414 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
415 return -EOVERFLOW;
416 tmp.st_mode = stat->mode;
417 tmp.st_nlink = stat->nlink;
418 if (tmp.st_nlink != stat->nlink)
419 return -EOVERFLOW;
420 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
421 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
422 tmp.st_rdev = new_encode_dev(stat->rdev);
423 tmp.st_size = stat->size;
424 tmp.st_atime = stat->atime.tv_sec;
425 tmp.st_mtime = stat->mtime.tv_sec;
426 tmp.st_ctime = stat->ctime.tv_sec;
427#ifdef STAT_HAVE_NSEC
428 tmp.st_atime_nsec = stat->atime.tv_nsec;
429 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
430 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
431#endif
432 tmp.st_blocks = stat->blocks;
433 tmp.st_blksize = stat->blksize;
434 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
435}
436
437SYSCALL_DEFINE2(newstat, const char __user *, filename,
438 struct stat __user *, statbuf)
439{
440 struct kstat stat;
441 int error = vfs_stat(filename, &stat);
442
443 if (error)
444 return error;
445 return cp_new_stat(&stat, statbuf);
446}
447
448SYSCALL_DEFINE2(newlstat, const char __user *, filename,
449 struct stat __user *, statbuf)
450{
451 struct kstat stat;
452 int error;
453
454 error = vfs_lstat(filename, &stat);
455 if (error)
456 return error;
457
458 return cp_new_stat(&stat, statbuf);
459}
460
461#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
462SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
463 struct stat __user *, statbuf, int, flag)
464{
465 struct kstat stat;
466 int error;
467
468 error = vfs_fstatat(dfd, filename, &stat, flag);
469 if (error)
470 return error;
471 return cp_new_stat(&stat, statbuf);
472}
473#endif
474
475SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
476{
477 struct kstat stat;
478 int error = vfs_fstat(fd, &stat);
479
480 if (!error)
481 error = cp_new_stat(&stat, statbuf);
482
483 return error;
484}
485#endif
486
487static int do_readlinkat(int dfd, const char __user *pathname,
488 char __user *buf, int bufsiz)
489{
490 struct path path;
491 int error;
492 int empty = 0;
493 unsigned int lookup_flags = LOOKUP_EMPTY;
494
495 if (bufsiz <= 0)
496 return -EINVAL;
497
498retry:
499 error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
500 if (!error) {
501 struct inode *inode = d_backing_inode(path.dentry);
502
503 error = empty ? -ENOENT : -EINVAL;
504 /*
505 * AFS mountpoints allow readlink(2) but are not symlinks
506 */
507 if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
508 error = security_inode_readlink(path.dentry);
509 if (!error) {
510 touch_atime(&path);
511 error = vfs_readlink(path.dentry, buf, bufsiz);
512 }
513 }
514 path_put(&path);
515 if (retry_estale(error, lookup_flags)) {
516 lookup_flags |= LOOKUP_REVAL;
517 goto retry;
518 }
519 }
520 return error;
521}
522
523SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
524 char __user *, buf, int, bufsiz)
525{
526 return do_readlinkat(dfd, pathname, buf, bufsiz);
527}
528
529SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
530 int, bufsiz)
531{
532 return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
533}
534
535
536/* ---------- LFS-64 ----------- */
537#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
538
539#ifndef INIT_STRUCT_STAT64_PADDING
540# define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
541#endif
542
543static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
544{
545 struct stat64 tmp;
546
547 INIT_STRUCT_STAT64_PADDING(tmp);
548#ifdef CONFIG_MIPS
549 /* mips has weird padding, so we don't get 64 bits there */
550 tmp.st_dev = new_encode_dev(stat->dev);
551 tmp.st_rdev = new_encode_dev(stat->rdev);
552#else
553 tmp.st_dev = huge_encode_dev(stat->dev);
554 tmp.st_rdev = huge_encode_dev(stat->rdev);
555#endif
556 tmp.st_ino = stat->ino;
557 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
558 return -EOVERFLOW;
559#ifdef STAT64_HAS_BROKEN_ST_INO
560 tmp.__st_ino = stat->ino;
561#endif
562 tmp.st_mode = stat->mode;
563 tmp.st_nlink = stat->nlink;
564 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
565 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
566 tmp.st_atime = stat->atime.tv_sec;
567 tmp.st_atime_nsec = stat->atime.tv_nsec;
568 tmp.st_mtime = stat->mtime.tv_sec;
569 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
570 tmp.st_ctime = stat->ctime.tv_sec;
571 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
572 tmp.st_size = stat->size;
573 tmp.st_blocks = stat->blocks;
574 tmp.st_blksize = stat->blksize;
575 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
576}
577
578SYSCALL_DEFINE2(stat64, const char __user *, filename,
579 struct stat64 __user *, statbuf)
580{
581 struct kstat stat;
582 int error = vfs_stat(filename, &stat);
583
584 if (!error)
585 error = cp_new_stat64(&stat, statbuf);
586
587 return error;
588}
589
590SYSCALL_DEFINE2(lstat64, const char __user *, filename,
591 struct stat64 __user *, statbuf)
592{
593 struct kstat stat;
594 int error = vfs_lstat(filename, &stat);
595
596 if (!error)
597 error = cp_new_stat64(&stat, statbuf);
598
599 return error;
600}
601
602SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
603{
604 struct kstat stat;
605 int error = vfs_fstat(fd, &stat);
606
607 if (!error)
608 error = cp_new_stat64(&stat, statbuf);
609
610 return error;
611}
612
613SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
614 struct stat64 __user *, statbuf, int, flag)
615{
616 struct kstat stat;
617 int error;
618
619 error = vfs_fstatat(dfd, filename, &stat, flag);
620 if (error)
621 return error;
622 return cp_new_stat64(&stat, statbuf);
623}
624#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
625
626static noinline_for_stack int
627cp_statx(const struct kstat *stat, struct statx __user *buffer)
628{
629 struct statx tmp;
630
631 memset(&tmp, 0, sizeof(tmp));
632
633 /* STATX_CHANGE_COOKIE is kernel-only for now */
634 tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE;
635 tmp.stx_blksize = stat->blksize;
636 /* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */
637 tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC;
638 tmp.stx_nlink = stat->nlink;
639 tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
640 tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
641 tmp.stx_mode = stat->mode;
642 tmp.stx_ino = stat->ino;
643 tmp.stx_size = stat->size;
644 tmp.stx_blocks = stat->blocks;
645 tmp.stx_attributes_mask = stat->attributes_mask;
646 tmp.stx_atime.tv_sec = stat->atime.tv_sec;
647 tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
648 tmp.stx_btime.tv_sec = stat->btime.tv_sec;
649 tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
650 tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
651 tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
652 tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
653 tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
654 tmp.stx_rdev_major = MAJOR(stat->rdev);
655 tmp.stx_rdev_minor = MINOR(stat->rdev);
656 tmp.stx_dev_major = MAJOR(stat->dev);
657 tmp.stx_dev_minor = MINOR(stat->dev);
658 tmp.stx_mnt_id = stat->mnt_id;
659 tmp.stx_dio_mem_align = stat->dio_mem_align;
660 tmp.stx_dio_offset_align = stat->dio_offset_align;
661
662 return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
663}
664
665int do_statx(int dfd, struct filename *filename, unsigned int flags,
666 unsigned int mask, struct statx __user *buffer)
667{
668 struct kstat stat;
669 int error;
670
671 if (mask & STATX__RESERVED)
672 return -EINVAL;
673 if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
674 return -EINVAL;
675
676 /* STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
677 * from userland.
678 */
679 mask &= ~STATX_CHANGE_COOKIE;
680
681 error = vfs_statx(dfd, filename, flags, &stat, mask);
682 if (error)
683 return error;
684
685 return cp_statx(&stat, buffer);
686}
687
688/**
689 * sys_statx - System call to get enhanced stats
690 * @dfd: Base directory to pathwalk from *or* fd to stat.
691 * @filename: File to stat or "" with AT_EMPTY_PATH
692 * @flags: AT_* flags to control pathwalk.
693 * @mask: Parts of statx struct actually required.
694 * @buffer: Result buffer.
695 *
696 * Note that fstat() can be emulated by setting dfd to the fd of interest,
697 * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
698 */
699SYSCALL_DEFINE5(statx,
700 int, dfd, const char __user *, filename, unsigned, flags,
701 unsigned int, mask,
702 struct statx __user *, buffer)
703{
704 int ret;
705 struct filename *name;
706
707 name = getname_flags(filename, getname_statx_lookup_flags(flags), NULL);
708 ret = do_statx(dfd, name, flags, mask, buffer);
709 putname(name);
710
711 return ret;
712}
713
714#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
715static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
716{
717 struct compat_stat tmp;
718
719 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
720 return -EOVERFLOW;
721 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
722 return -EOVERFLOW;
723
724 memset(&tmp, 0, sizeof(tmp));
725 tmp.st_dev = new_encode_dev(stat->dev);
726 tmp.st_ino = stat->ino;
727 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
728 return -EOVERFLOW;
729 tmp.st_mode = stat->mode;
730 tmp.st_nlink = stat->nlink;
731 if (tmp.st_nlink != stat->nlink)
732 return -EOVERFLOW;
733 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
734 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
735 tmp.st_rdev = new_encode_dev(stat->rdev);
736 if ((u64) stat->size > MAX_NON_LFS)
737 return -EOVERFLOW;
738 tmp.st_size = stat->size;
739 tmp.st_atime = stat->atime.tv_sec;
740 tmp.st_atime_nsec = stat->atime.tv_nsec;
741 tmp.st_mtime = stat->mtime.tv_sec;
742 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
743 tmp.st_ctime = stat->ctime.tv_sec;
744 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
745 tmp.st_blocks = stat->blocks;
746 tmp.st_blksize = stat->blksize;
747 return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
748}
749
750COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
751 struct compat_stat __user *, statbuf)
752{
753 struct kstat stat;
754 int error;
755
756 error = vfs_stat(filename, &stat);
757 if (error)
758 return error;
759 return cp_compat_stat(&stat, statbuf);
760}
761
762COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
763 struct compat_stat __user *, statbuf)
764{
765 struct kstat stat;
766 int error;
767
768 error = vfs_lstat(filename, &stat);
769 if (error)
770 return error;
771 return cp_compat_stat(&stat, statbuf);
772}
773
774#ifndef __ARCH_WANT_STAT64
775COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
776 const char __user *, filename,
777 struct compat_stat __user *, statbuf, int, flag)
778{
779 struct kstat stat;
780 int error;
781
782 error = vfs_fstatat(dfd, filename, &stat, flag);
783 if (error)
784 return error;
785 return cp_compat_stat(&stat, statbuf);
786}
787#endif
788
789COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
790 struct compat_stat __user *, statbuf)
791{
792 struct kstat stat;
793 int error = vfs_fstat(fd, &stat);
794
795 if (!error)
796 error = cp_compat_stat(&stat, statbuf);
797 return error;
798}
799#endif
800
801/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
802void __inode_add_bytes(struct inode *inode, loff_t bytes)
803{
804 inode->i_blocks += bytes >> 9;
805 bytes &= 511;
806 inode->i_bytes += bytes;
807 if (inode->i_bytes >= 512) {
808 inode->i_blocks++;
809 inode->i_bytes -= 512;
810 }
811}
812EXPORT_SYMBOL(__inode_add_bytes);
813
814void inode_add_bytes(struct inode *inode, loff_t bytes)
815{
816 spin_lock(&inode->i_lock);
817 __inode_add_bytes(inode, bytes);
818 spin_unlock(&inode->i_lock);
819}
820
821EXPORT_SYMBOL(inode_add_bytes);
822
823void __inode_sub_bytes(struct inode *inode, loff_t bytes)
824{
825 inode->i_blocks -= bytes >> 9;
826 bytes &= 511;
827 if (inode->i_bytes < bytes) {
828 inode->i_blocks--;
829 inode->i_bytes += 512;
830 }
831 inode->i_bytes -= bytes;
832}
833
834EXPORT_SYMBOL(__inode_sub_bytes);
835
836void inode_sub_bytes(struct inode *inode, loff_t bytes)
837{
838 spin_lock(&inode->i_lock);
839 __inode_sub_bytes(inode, bytes);
840 spin_unlock(&inode->i_lock);
841}
842
843EXPORT_SYMBOL(inode_sub_bytes);
844
845loff_t inode_get_bytes(struct inode *inode)
846{
847 loff_t ret;
848
849 spin_lock(&inode->i_lock);
850 ret = __inode_get_bytes(inode);
851 spin_unlock(&inode->i_lock);
852 return ret;
853}
854
855EXPORT_SYMBOL(inode_get_bytes);
856
857void inode_set_bytes(struct inode *inode, loff_t bytes)
858{
859 /* Caller is here responsible for sufficient locking
860 * (ie. inode->i_lock) */
861 inode->i_blocks = bytes >> 9;
862 inode->i_bytes = bytes & 511;
863}
864
865EXPORT_SYMBOL(inode_set_bytes);