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 <trace/events/timestamp.h>
27
28#include "internal.h"
29#include "mount.h"
30
31/**
32 * fill_mg_cmtime - Fill in the mtime and ctime and flag ctime as QUERIED
33 * @stat: where to store the resulting values
34 * @request_mask: STATX_* values requested
35 * @inode: inode from which to grab the c/mtime
36 *
37 * Given @inode, grab the ctime and mtime out if it and store the result
38 * in @stat. When fetching the value, flag it as QUERIED (if not already)
39 * so the next write will record a distinct timestamp.
40 *
41 * NB: The QUERIED flag is tracked in the ctime, but we set it there even
42 * if only the mtime was requested, as that ensures that the next mtime
43 * change will be distinct.
44 */
45void fill_mg_cmtime(struct kstat *stat, u32 request_mask, struct inode *inode)
46{
47 atomic_t *pcn = (atomic_t *)&inode->i_ctime_nsec;
48
49 /* If neither time was requested, then don't report them */
50 if (!(request_mask & (STATX_CTIME|STATX_MTIME))) {
51 stat->result_mask &= ~(STATX_CTIME|STATX_MTIME);
52 return;
53 }
54
55 stat->mtime = inode_get_mtime(inode);
56 stat->ctime.tv_sec = inode->i_ctime_sec;
57 stat->ctime.tv_nsec = (u32)atomic_read(v: pcn);
58 if (!(stat->ctime.tv_nsec & I_CTIME_QUERIED))
59 stat->ctime.tv_nsec = ((u32)atomic_fetch_or(I_CTIME_QUERIED, v: pcn));
60 stat->ctime.tv_nsec &= ~I_CTIME_QUERIED;
61 trace_fill_mg_cmtime(inode, ctime: &stat->ctime, mtime: &stat->mtime);
62}
63EXPORT_SYMBOL(fill_mg_cmtime);
64
65/**
66 * generic_fillattr - Fill in the basic attributes from the inode struct
67 * @idmap: idmap of the mount the inode was found from
68 * @request_mask: statx request_mask
69 * @inode: Inode to use as the source
70 * @stat: Where to fill in the attributes
71 *
72 * Fill in the basic attributes in the kstat structure from data that's to be
73 * found on the VFS inode structure. This is the default if no getattr inode
74 * operation is supplied.
75 *
76 * If the inode has been found through an idmapped mount the idmap of
77 * the vfsmount must be passed through @idmap. This function will then
78 * take care to map the inode according to @idmap before filling in the
79 * uid and gid filds. On non-idmapped mounts or if permission checking is to be
80 * performed on the raw inode simply pass @nop_mnt_idmap.
81 */
82void generic_fillattr(struct mnt_idmap *idmap, u32 request_mask,
83 struct inode *inode, struct kstat *stat)
84{
85 vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);
86 vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);
87
88 stat->dev = inode->i_sb->s_dev;
89 stat->ino = inode->i_ino;
90 stat->mode = inode->i_mode;
91 stat->nlink = inode->i_nlink;
92 stat->uid = vfsuid_into_kuid(vfsuid);
93 stat->gid = vfsgid_into_kgid(vfsgid);
94 stat->rdev = inode->i_rdev;
95 stat->size = i_size_read(inode);
96 stat->atime = inode_get_atime(inode);
97
98 if (is_mgtime(inode)) {
99 fill_mg_cmtime(stat, request_mask, inode);
100 } else {
101 stat->ctime = inode_get_ctime(inode);
102 stat->mtime = inode_get_mtime(inode);
103 }
104
105 stat->blksize = i_blocksize(node: inode);
106 stat->blocks = inode->i_blocks;
107
108 if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) {
109 stat->result_mask |= STATX_CHANGE_COOKIE;
110 stat->change_cookie = inode_query_iversion(inode);
111 }
112
113}
114EXPORT_SYMBOL(generic_fillattr);
115
116/**
117 * generic_fill_statx_attr - Fill in the statx attributes from the inode flags
118 * @inode: Inode to use as the source
119 * @stat: Where to fill in the attribute flags
120 *
121 * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the
122 * inode that are published on i_flags and enforced by the VFS.
123 */
124void generic_fill_statx_attr(struct inode *inode, struct kstat *stat)
125{
126 if (inode->i_flags & S_IMMUTABLE)
127 stat->attributes |= STATX_ATTR_IMMUTABLE;
128 if (inode->i_flags & S_APPEND)
129 stat->attributes |= STATX_ATTR_APPEND;
130 stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS;
131}
132EXPORT_SYMBOL(generic_fill_statx_attr);
133
134/**
135 * generic_fill_statx_atomic_writes - Fill in atomic writes statx attributes
136 * @stat: Where to fill in the attribute flags
137 * @unit_min: Minimum supported atomic write length in bytes
138 * @unit_max: Maximum supported atomic write length in bytes
139 * @unit_max_opt: Optimised maximum supported atomic write length in bytes
140 *
141 * Fill in the STATX{_ATTR}_WRITE_ATOMIC flags in the kstat structure from
142 * atomic write unit_min and unit_max values.
143 */
144void generic_fill_statx_atomic_writes(struct kstat *stat,
145 unsigned int unit_min,
146 unsigned int unit_max,
147 unsigned int unit_max_opt)
148{
149 /* Confirm that the request type is known */
150 stat->result_mask |= STATX_WRITE_ATOMIC;
151
152 /* Confirm that the file attribute type is known */
153 stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC;
154
155 if (unit_min) {
156 stat->atomic_write_unit_min = unit_min;
157 stat->atomic_write_unit_max = unit_max;
158 stat->atomic_write_unit_max_opt = unit_max_opt;
159 /* Initially only allow 1x segment */
160 stat->atomic_write_segments_max = 1;
161
162 /* Confirm atomic writes are actually supported */
163 stat->attributes |= STATX_ATTR_WRITE_ATOMIC;
164 }
165}
166EXPORT_SYMBOL_GPL(generic_fill_statx_atomic_writes);
167
168/**
169 * vfs_getattr_nosec - getattr without security checks
170 * @path: file to get attributes from
171 * @stat: structure to return attributes in
172 * @request_mask: STATX_xxx flags indicating what the caller wants
173 * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
174 *
175 * Get attributes without calling security_inode_getattr.
176 *
177 * Currently the only caller other than vfs_getattr is internal to the
178 * filehandle lookup code, which uses only the inode number and returns no
179 * attributes to any user. Any other code probably wants vfs_getattr.
180 */
181int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
182 u32 request_mask, unsigned int query_flags)
183{
184 struct mnt_idmap *idmap;
185 struct inode *inode = d_backing_inode(upper: path->dentry);
186
187 memset(stat, 0, sizeof(*stat));
188 stat->result_mask |= STATX_BASIC_STATS;
189 query_flags &= AT_STATX_SYNC_TYPE;
190
191 /* allow the fs to override these if it really wants to */
192 /* SB_NOATIME means filesystem supplies dummy atime value */
193 if (inode->i_sb->s_flags & SB_NOATIME)
194 stat->result_mask &= ~STATX_ATIME;
195
196 /*
197 * Note: If you add another clause to set an attribute flag, please
198 * update attributes_mask below.
199 */
200 if (IS_AUTOMOUNT(inode))
201 stat->attributes |= STATX_ATTR_AUTOMOUNT;
202
203 if (IS_DAX(inode))
204 stat->attributes |= STATX_ATTR_DAX;
205
206 stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT |
207 STATX_ATTR_DAX);
208
209 idmap = mnt_idmap(mnt: path->mnt);
210 if (inode->i_op->getattr) {
211 int ret;
212
213 ret = inode->i_op->getattr(idmap, path, stat, request_mask,
214 query_flags);
215 if (ret)
216 return ret;
217 } else {
218 generic_fillattr(idmap, request_mask, inode, stat);
219 }
220
221 /*
222 * If this is a block device inode, override the filesystem attributes
223 * with the block device specific parameters that need to be obtained
224 * from the bdev backing inode.
225 */
226 if (S_ISBLK(stat->mode))
227 bdev_statx(path, stat, request_mask);
228
229 return 0;
230}
231EXPORT_SYMBOL(vfs_getattr_nosec);
232
233/*
234 * vfs_getattr - Get the enhanced basic attributes of a file
235 * @path: The file of interest
236 * @stat: Where to return the statistics
237 * @request_mask: STATX_xxx flags indicating what the caller wants
238 * @query_flags: Query mode (AT_STATX_SYNC_TYPE)
239 *
240 * Ask the filesystem for a file's attributes. The caller must indicate in
241 * request_mask and query_flags to indicate what they want.
242 *
243 * If the file is remote, the filesystem can be forced to update the attributes
244 * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
245 * suppress the update by passing AT_STATX_DONT_SYNC.
246 *
247 * Bits must have been set in request_mask to indicate which attributes the
248 * caller wants retrieving. Any such attribute not requested may be returned
249 * anyway, but the value may be approximate, and, if remote, may not have been
250 * synchronised with the server.
251 *
252 * 0 will be returned on success, and a -ve error code if unsuccessful.
253 */
254int vfs_getattr(const struct path *path, struct kstat *stat,
255 u32 request_mask, unsigned int query_flags)
256{
257 int retval;
258
259 retval = security_inode_getattr(path);
260 if (unlikely(retval))
261 return retval;
262 return vfs_getattr_nosec(path, stat, request_mask, query_flags);
263}
264EXPORT_SYMBOL(vfs_getattr);
265
266/**
267 * vfs_fstat - Get the basic attributes by file descriptor
268 * @fd: The file descriptor referring to the file of interest
269 * @stat: The result structure to fill in.
270 *
271 * This function is a wrapper around vfs_getattr(). The main difference is
272 * that it uses a file descriptor to determine the file location.
273 *
274 * 0 will be returned on success, and a -ve error code if unsuccessful.
275 */
276int vfs_fstat(int fd, struct kstat *stat)
277{
278 CLASS(fd_raw, f)(fd);
279 if (fd_empty(f))
280 return -EBADF;
281 return vfs_getattr(&fd_file(f)->f_path, stat, STATX_BASIC_STATS, 0);
282}
283
284static int statx_lookup_flags(int flags)
285{
286 int lookup_flags = 0;
287
288 if (!(flags & AT_SYMLINK_NOFOLLOW))
289 lookup_flags |= LOOKUP_FOLLOW;
290 if (!(flags & AT_NO_AUTOMOUNT))
291 lookup_flags |= LOOKUP_AUTOMOUNT;
292
293 return lookup_flags;
294}
295
296static int vfs_statx_path(struct path *path, int flags, struct kstat *stat,
297 u32 request_mask)
298{
299 int error = vfs_getattr(path, stat, request_mask, flags);
300 if (error)
301 return error;
302
303 if (request_mask & STATX_MNT_ID_UNIQUE) {
304 stat->mnt_id = real_mount(mnt: path->mnt)->mnt_id_unique;
305 stat->result_mask |= STATX_MNT_ID_UNIQUE;
306 } else {
307 stat->mnt_id = real_mount(mnt: path->mnt)->mnt_id;
308 stat->result_mask |= STATX_MNT_ID;
309 }
310
311 if (path_mounted(path))
312 stat->attributes |= STATX_ATTR_MOUNT_ROOT;
313 stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
314 return 0;
315}
316
317static int vfs_statx_fd(int fd, int flags, struct kstat *stat,
318 u32 request_mask)
319{
320 CLASS(fd_raw, f)(fd);
321 if (fd_empty(f))
322 return -EBADF;
323 return vfs_statx_path(path: &fd_file(f)->f_path, flags, stat, request_mask);
324}
325
326/**
327 * vfs_statx - Get basic and extra attributes by filename
328 * @dfd: A file descriptor representing the base dir for a relative filename
329 * @filename: The name of the file of interest
330 * @flags: Flags to control the query
331 * @stat: The result structure to fill in.
332 * @request_mask: STATX_xxx flags indicating what the caller wants
333 *
334 * This function is a wrapper around vfs_getattr(). The main difference is
335 * that it uses a filename and base directory to determine the file location.
336 * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
337 * at the given name from being referenced.
338 *
339 * 0 will be returned on success, and a -ve error code if unsuccessful.
340 */
341static int vfs_statx(int dfd, struct filename *filename, int flags,
342 struct kstat *stat, u32 request_mask)
343{
344 struct path path;
345 unsigned int lookup_flags = statx_lookup_flags(flags);
346 int error;
347
348 if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH |
349 AT_STATX_SYNC_TYPE))
350 return -EINVAL;
351
352retry:
353 error = filename_lookup(dfd, name: filename, flags: lookup_flags, path: &path, NULL);
354 if (error)
355 return error;
356 error = vfs_statx_path(path: &path, flags, stat, request_mask);
357 path_put(&path);
358 if (retry_estale(error, flags: lookup_flags)) {
359 lookup_flags |= LOOKUP_REVAL;
360 goto retry;
361 }
362 return error;
363}
364
365int vfs_fstatat(int dfd, const char __user *filename,
366 struct kstat *stat, int flags)
367{
368 int ret;
369 int statx_flags = flags | AT_NO_AUTOMOUNT;
370 struct filename *name = getname_maybe_null(name: filename, flags);
371
372 if (!name && dfd >= 0)
373 return vfs_fstat(fd: dfd, stat);
374
375 ret = vfs_statx(dfd, filename: name, flags: statx_flags, stat, STATX_BASIC_STATS);
376 putname(name);
377
378 return ret;
379}
380
381#ifdef __ARCH_WANT_OLD_STAT
382
383/*
384 * For backward compatibility? Maybe this should be moved
385 * into arch/i386 instead?
386 */
387static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
388{
389 static int warncount = 5;
390 struct __old_kernel_stat tmp;
391
392 if (warncount > 0) {
393 warncount--;
394 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
395 current->comm);
396 } else if (warncount < 0) {
397 /* it's laughable, but... */
398 warncount = 0;
399 }
400
401 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
402 tmp.st_dev = old_encode_dev(dev: stat->dev);
403 tmp.st_ino = stat->ino;
404 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
405 return -EOVERFLOW;
406 tmp.st_mode = stat->mode;
407 tmp.st_nlink = stat->nlink;
408 if (tmp.st_nlink != stat->nlink)
409 return -EOVERFLOW;
410 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
411 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
412 tmp.st_rdev = old_encode_dev(dev: stat->rdev);
413#if BITS_PER_LONG == 32
414 if (stat->size > MAX_NON_LFS)
415 return -EOVERFLOW;
416#endif
417 tmp.st_size = stat->size;
418 tmp.st_atime = stat->atime.tv_sec;
419 tmp.st_mtime = stat->mtime.tv_sec;
420 tmp.st_ctime = stat->ctime.tv_sec;
421 return copy_to_user(to: statbuf,from: &tmp,n: sizeof(tmp)) ? -EFAULT : 0;
422}
423
424SYSCALL_DEFINE2(stat, const char __user *, filename,
425 struct __old_kernel_stat __user *, statbuf)
426{
427 struct kstat stat;
428 int error;
429
430 error = vfs_stat(filename, stat: &stat);
431 if (unlikely(error))
432 return error;
433
434 return cp_old_stat(stat: &stat, statbuf);
435}
436
437SYSCALL_DEFINE2(lstat, const char __user *, filename,
438 struct __old_kernel_stat __user *, statbuf)
439{
440 struct kstat stat;
441 int error;
442
443 error = vfs_lstat(name: filename, stat: &stat);
444 if (unlikely(error))
445 return error;
446
447 return cp_old_stat(stat: &stat, statbuf);
448}
449
450SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
451{
452 struct kstat stat;
453 int error;
454
455 error = vfs_fstat(fd, stat: &stat);
456 if (unlikely(error))
457 return error;
458
459 return cp_old_stat(stat: &stat, statbuf);
460}
461
462#endif /* __ARCH_WANT_OLD_STAT */
463
464#ifdef __ARCH_WANT_NEW_STAT
465
466#ifndef INIT_STRUCT_STAT_PADDING
467# define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
468#endif
469
470static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
471{
472 struct stat tmp;
473
474 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(dev: stat->dev))
475 return -EOVERFLOW;
476 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(dev: stat->rdev))
477 return -EOVERFLOW;
478#if BITS_PER_LONG == 32
479 if (stat->size > MAX_NON_LFS)
480 return -EOVERFLOW;
481#endif
482
483 INIT_STRUCT_STAT_PADDING(tmp);
484 tmp.st_dev = new_encode_dev(dev: stat->dev);
485 tmp.st_ino = stat->ino;
486 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
487 return -EOVERFLOW;
488 tmp.st_mode = stat->mode;
489 tmp.st_nlink = stat->nlink;
490 if (tmp.st_nlink != stat->nlink)
491 return -EOVERFLOW;
492 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
493 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
494 tmp.st_rdev = new_encode_dev(dev: stat->rdev);
495 tmp.st_size = stat->size;
496 tmp.st_atime = stat->atime.tv_sec;
497 tmp.st_mtime = stat->mtime.tv_sec;
498 tmp.st_ctime = stat->ctime.tv_sec;
499#ifdef STAT_HAVE_NSEC
500 tmp.st_atime_nsec = stat->atime.tv_nsec;
501 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
502 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
503#endif
504 tmp.st_blocks = stat->blocks;
505 tmp.st_blksize = stat->blksize;
506 return copy_to_user(to: statbuf,from: &tmp,n: sizeof(tmp)) ? -EFAULT : 0;
507}
508
509SYSCALL_DEFINE2(newstat, const char __user *, filename,
510 struct stat __user *, statbuf)
511{
512 struct kstat stat;
513 int error;
514
515 error = vfs_stat(filename, stat: &stat);
516 if (unlikely(error))
517 return error;
518
519 return cp_new_stat(stat: &stat, statbuf);
520}
521
522SYSCALL_DEFINE2(newlstat, const char __user *, filename,
523 struct stat __user *, statbuf)
524{
525 struct kstat stat;
526 int error;
527
528 error = vfs_lstat(name: filename, stat: &stat);
529 if (unlikely(error))
530 return error;
531
532 return cp_new_stat(stat: &stat, statbuf);
533}
534
535#if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
536SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
537 struct stat __user *, statbuf, int, flag)
538{
539 struct kstat stat;
540 int error;
541
542 error = vfs_fstatat(dfd, filename, stat: &stat, flags: flag);
543 if (unlikely(error))
544 return error;
545
546 return cp_new_stat(stat: &stat, statbuf);
547}
548#endif
549
550SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
551{
552 struct kstat stat;
553 int error;
554
555 error = vfs_fstat(fd, stat: &stat);
556 if (unlikely(error))
557 return error;
558
559 return cp_new_stat(stat: &stat, statbuf);
560}
561#endif
562
563static int do_readlinkat(int dfd, const char __user *pathname,
564 char __user *buf, int bufsiz)
565{
566 struct path path;
567 struct filename *name;
568 int error;
569 unsigned int lookup_flags = LOOKUP_EMPTY;
570
571 if (bufsiz <= 0)
572 return -EINVAL;
573
574retry:
575 name = getname_flags(pathname, lookup_flags);
576 error = filename_lookup(dfd, name, flags: lookup_flags, path: &path, NULL);
577 if (unlikely(error)) {
578 putname(name);
579 return error;
580 }
581
582 /*
583 * AFS mountpoints allow readlink(2) but are not symlinks
584 */
585 if (d_is_symlink(dentry: path.dentry) ||
586 d_backing_inode(upper: path.dentry)->i_op->readlink) {
587 error = security_inode_readlink(dentry: path.dentry);
588 if (!error) {
589 touch_atime(&path);
590 error = vfs_readlink(path.dentry, buf, bufsiz);
591 }
592 } else {
593 error = (name->name[0] == '\0') ? -ENOENT : -EINVAL;
594 }
595 path_put(&path);
596 putname(name);
597 if (retry_estale(error, flags: lookup_flags)) {
598 lookup_flags |= LOOKUP_REVAL;
599 goto retry;
600 }
601 return error;
602}
603
604SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
605 char __user *, buf, int, bufsiz)
606{
607 return do_readlinkat(dfd, pathname, buf, bufsiz);
608}
609
610SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
611 int, bufsiz)
612{
613 return do_readlinkat(AT_FDCWD, pathname: path, buf, bufsiz);
614}
615
616
617/* ---------- LFS-64 ----------- */
618#if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
619
620#ifndef INIT_STRUCT_STAT64_PADDING
621# define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
622#endif
623
624static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
625{
626 struct stat64 tmp;
627
628 INIT_STRUCT_STAT64_PADDING(tmp);
629#ifdef CONFIG_MIPS
630 /* mips has weird padding, so we don't get 64 bits there */
631 tmp.st_dev = new_encode_dev(stat->dev);
632 tmp.st_rdev = new_encode_dev(stat->rdev);
633#else
634 tmp.st_dev = huge_encode_dev(stat->dev);
635 tmp.st_rdev = huge_encode_dev(stat->rdev);
636#endif
637 tmp.st_ino = stat->ino;
638 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
639 return -EOVERFLOW;
640#ifdef STAT64_HAS_BROKEN_ST_INO
641 tmp.__st_ino = stat->ino;
642#endif
643 tmp.st_mode = stat->mode;
644 tmp.st_nlink = stat->nlink;
645 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
646 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
647 tmp.st_atime = stat->atime.tv_sec;
648 tmp.st_atime_nsec = stat->atime.tv_nsec;
649 tmp.st_mtime = stat->mtime.tv_sec;
650 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
651 tmp.st_ctime = stat->ctime.tv_sec;
652 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
653 tmp.st_size = stat->size;
654 tmp.st_blocks = stat->blocks;
655 tmp.st_blksize = stat->blksize;
656 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
657}
658
659SYSCALL_DEFINE2(stat64, const char __user *, filename,
660 struct stat64 __user *, statbuf)
661{
662 struct kstat stat;
663 int error = vfs_stat(filename, &stat);
664
665 if (!error)
666 error = cp_new_stat64(&stat, statbuf);
667
668 return error;
669}
670
671SYSCALL_DEFINE2(lstat64, const char __user *, filename,
672 struct stat64 __user *, statbuf)
673{
674 struct kstat stat;
675 int error = vfs_lstat(filename, &stat);
676
677 if (!error)
678 error = cp_new_stat64(&stat, statbuf);
679
680 return error;
681}
682
683SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
684{
685 struct kstat stat;
686 int error = vfs_fstat(fd, &stat);
687
688 if (!error)
689 error = cp_new_stat64(&stat, statbuf);
690
691 return error;
692}
693
694SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
695 struct stat64 __user *, statbuf, int, flag)
696{
697 struct kstat stat;
698 int error;
699
700 error = vfs_fstatat(dfd, filename, &stat, flag);
701 if (error)
702 return error;
703 return cp_new_stat64(&stat, statbuf);
704}
705#endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
706
707static noinline_for_stack int
708cp_statx(const struct kstat *stat, struct statx __user *buffer)
709{
710 struct statx tmp;
711
712 memset(&tmp, 0, sizeof(tmp));
713
714 /* STATX_CHANGE_COOKIE is kernel-only for now */
715 tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE;
716 tmp.stx_blksize = stat->blksize;
717 /* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */
718 tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC;
719 tmp.stx_nlink = stat->nlink;
720 tmp.stx_uid = from_kuid_munged(current_user_ns(), uid: stat->uid);
721 tmp.stx_gid = from_kgid_munged(current_user_ns(), gid: stat->gid);
722 tmp.stx_mode = stat->mode;
723 tmp.stx_ino = stat->ino;
724 tmp.stx_size = stat->size;
725 tmp.stx_blocks = stat->blocks;
726 tmp.stx_attributes_mask = stat->attributes_mask;
727 tmp.stx_atime.tv_sec = stat->atime.tv_sec;
728 tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
729 tmp.stx_btime.tv_sec = stat->btime.tv_sec;
730 tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
731 tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
732 tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
733 tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
734 tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
735 tmp.stx_rdev_major = MAJOR(stat->rdev);
736 tmp.stx_rdev_minor = MINOR(stat->rdev);
737 tmp.stx_dev_major = MAJOR(stat->dev);
738 tmp.stx_dev_minor = MINOR(stat->dev);
739 tmp.stx_mnt_id = stat->mnt_id;
740 tmp.stx_dio_mem_align = stat->dio_mem_align;
741 tmp.stx_dio_offset_align = stat->dio_offset_align;
742 tmp.stx_dio_read_offset_align = stat->dio_read_offset_align;
743 tmp.stx_subvol = stat->subvol;
744 tmp.stx_atomic_write_unit_min = stat->atomic_write_unit_min;
745 tmp.stx_atomic_write_unit_max = stat->atomic_write_unit_max;
746 tmp.stx_atomic_write_segments_max = stat->atomic_write_segments_max;
747 tmp.stx_atomic_write_unit_max_opt = stat->atomic_write_unit_max_opt;
748
749 return copy_to_user(to: buffer, from: &tmp, n: sizeof(tmp)) ? -EFAULT : 0;
750}
751
752int do_statx(int dfd, struct filename *filename, unsigned int flags,
753 unsigned int mask, struct statx __user *buffer)
754{
755 struct kstat stat;
756 int error;
757
758 if (mask & STATX__RESERVED)
759 return -EINVAL;
760 if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
761 return -EINVAL;
762
763 /*
764 * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
765 * from userland.
766 */
767 mask &= ~STATX_CHANGE_COOKIE;
768
769 error = vfs_statx(dfd, filename, flags, stat: &stat, request_mask: mask);
770 if (error)
771 return error;
772
773 return cp_statx(stat: &stat, buffer);
774}
775
776int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
777 struct statx __user *buffer)
778{
779 struct kstat stat;
780 int error;
781
782 if (mask & STATX__RESERVED)
783 return -EINVAL;
784 if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
785 return -EINVAL;
786
787 /*
788 * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests
789 * from userland.
790 */
791 mask &= ~STATX_CHANGE_COOKIE;
792
793 error = vfs_statx_fd(fd, flags, stat: &stat, request_mask: mask);
794 if (error)
795 return error;
796
797 return cp_statx(stat: &stat, buffer);
798}
799
800/**
801 * sys_statx - System call to get enhanced stats
802 * @dfd: Base directory to pathwalk from *or* fd to stat.
803 * @filename: File to stat or either NULL or "" with AT_EMPTY_PATH
804 * @flags: AT_* flags to control pathwalk.
805 * @mask: Parts of statx struct actually required.
806 * @buffer: Result buffer.
807 *
808 * Note that fstat() can be emulated by setting dfd to the fd of interest,
809 * supplying "" (or preferably NULL) as the filename and setting AT_EMPTY_PATH
810 * in the flags.
811 */
812SYSCALL_DEFINE5(statx,
813 int, dfd, const char __user *, filename, unsigned, flags,
814 unsigned int, mask,
815 struct statx __user *, buffer)
816{
817 int ret;
818 struct filename *name = getname_maybe_null(name: filename, flags);
819
820 if (!name && dfd >= 0)
821 return do_statx_fd(fd: dfd, flags: flags & ~AT_NO_AUTOMOUNT, mask, buffer);
822
823 ret = do_statx(dfd, filename: name, flags, mask, buffer);
824 putname(name);
825
826 return ret;
827}
828
829#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT)
830static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
831{
832 struct compat_stat tmp;
833
834 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(dev: stat->dev))
835 return -EOVERFLOW;
836 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(dev: stat->rdev))
837 return -EOVERFLOW;
838
839 memset(&tmp, 0, sizeof(tmp));
840 tmp.st_dev = new_encode_dev(dev: stat->dev);
841 tmp.st_ino = stat->ino;
842 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
843 return -EOVERFLOW;
844 tmp.st_mode = stat->mode;
845 tmp.st_nlink = stat->nlink;
846 if (tmp.st_nlink != stat->nlink)
847 return -EOVERFLOW;
848 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
849 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
850 tmp.st_rdev = new_encode_dev(dev: stat->rdev);
851 if ((u64) stat->size > MAX_NON_LFS)
852 return -EOVERFLOW;
853 tmp.st_size = stat->size;
854 tmp.st_atime = stat->atime.tv_sec;
855 tmp.st_atime_nsec = stat->atime.tv_nsec;
856 tmp.st_mtime = stat->mtime.tv_sec;
857 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
858 tmp.st_ctime = stat->ctime.tv_sec;
859 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
860 tmp.st_blocks = stat->blocks;
861 tmp.st_blksize = stat->blksize;
862 return copy_to_user(to: ubuf, from: &tmp, n: sizeof(tmp)) ? -EFAULT : 0;
863}
864
865COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
866 struct compat_stat __user *, statbuf)
867{
868 struct kstat stat;
869 int error;
870
871 error = vfs_stat(filename, stat: &stat);
872 if (error)
873 return error;
874 return cp_compat_stat(stat: &stat, ubuf: statbuf);
875}
876
877COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
878 struct compat_stat __user *, statbuf)
879{
880 struct kstat stat;
881 int error;
882
883 error = vfs_lstat(name: filename, stat: &stat);
884 if (error)
885 return error;
886 return cp_compat_stat(stat: &stat, ubuf: statbuf);
887}
888
889#ifndef __ARCH_WANT_STAT64
890COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
891 const char __user *, filename,
892 struct compat_stat __user *, statbuf, int, flag)
893{
894 struct kstat stat;
895 int error;
896
897 error = vfs_fstatat(dfd, filename, stat: &stat, flags: flag);
898 if (error)
899 return error;
900 return cp_compat_stat(stat: &stat, ubuf: statbuf);
901}
902#endif
903
904COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
905 struct compat_stat __user *, statbuf)
906{
907 struct kstat stat;
908 int error = vfs_fstat(fd, stat: &stat);
909
910 if (!error)
911 error = cp_compat_stat(stat: &stat, ubuf: statbuf);
912 return error;
913}
914#endif
915
916/* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
917void __inode_add_bytes(struct inode *inode, loff_t bytes)
918{
919 inode->i_blocks += bytes >> 9;
920 bytes &= 511;
921 inode->i_bytes += bytes;
922 if (inode->i_bytes >= 512) {
923 inode->i_blocks++;
924 inode->i_bytes -= 512;
925 }
926}
927EXPORT_SYMBOL(__inode_add_bytes);
928
929void inode_add_bytes(struct inode *inode, loff_t bytes)
930{
931 spin_lock(lock: &inode->i_lock);
932 __inode_add_bytes(inode, bytes);
933 spin_unlock(lock: &inode->i_lock);
934}
935
936EXPORT_SYMBOL(inode_add_bytes);
937
938void __inode_sub_bytes(struct inode *inode, loff_t bytes)
939{
940 inode->i_blocks -= bytes >> 9;
941 bytes &= 511;
942 if (inode->i_bytes < bytes) {
943 inode->i_blocks--;
944 inode->i_bytes += 512;
945 }
946 inode->i_bytes -= bytes;
947}
948
949EXPORT_SYMBOL(__inode_sub_bytes);
950
951void inode_sub_bytes(struct inode *inode, loff_t bytes)
952{
953 spin_lock(lock: &inode->i_lock);
954 __inode_sub_bytes(inode, bytes);
955 spin_unlock(lock: &inode->i_lock);
956}
957
958EXPORT_SYMBOL(inode_sub_bytes);
959
960loff_t inode_get_bytes(struct inode *inode)
961{
962 loff_t ret;
963
964 spin_lock(lock: &inode->i_lock);
965 ret = __inode_get_bytes(inode);
966 spin_unlock(lock: &inode->i_lock);
967 return ret;
968}
969
970EXPORT_SYMBOL(inode_get_bytes);
971
972void inode_set_bytes(struct inode *inode, loff_t bytes)
973{
974 /* Caller is here responsible for sufficient locking
975 * (ie. inode->i_lock) */
976 inode->i_blocks = bytes >> 9;
977 inode->i_bytes = bytes & 511;
978}
979
980EXPORT_SYMBOL(inode_set_bytes);
981

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source code of linux/fs/stat.c