1 // SPDX-License-Identifier: GPL-2.0
5 * Copyright (C) 1991, 1992 Linus Torvalds
8 #include <linux/export.h>
10 #include <linux/errno.h>
11 #include <linux/file.h>
12 #include <linux/highuid.h>
14 #include <linux/namei.h>
15 #include <linux/security.h>
16 #include <linux/cred.h>
17 #include <linux/syscalls.h>
18 #include <linux/pagemap.h>
19 #include <linux/compat.h>
21 #include <linux/uaccess.h>
22 #include <asm/unistd.h>
28 * generic_fillattr - Fill in the basic attributes from the inode struct
29 * @inode: Inode to use as the source
30 * @stat: Where to fill in the attributes
32 * Fill in the basic attributes in the kstat structure from data that's to be
33 * found on the VFS inode structure. This is the default if no getattr inode
34 * operation is supplied.
36 void generic_fillattr(struct inode *inode, struct kstat *stat)
38 stat->dev = inode->i_sb->s_dev;
39 stat->ino = inode->i_ino;
40 stat->mode = inode->i_mode;
41 stat->nlink = inode->i_nlink;
42 stat->uid = inode->i_uid;
43 stat->gid = inode->i_gid;
44 stat->rdev = inode->i_rdev;
45 stat->size = i_size_read(inode);
46 stat->atime = inode->i_atime;
47 stat->mtime = inode->i_mtime;
48 stat->ctime = inode->i_ctime;
49 stat->blksize = i_blocksize(inode);
50 stat->blocks = inode->i_blocks;
52 EXPORT_SYMBOL(generic_fillattr);
55 * vfs_getattr_nosec - getattr without security checks
56 * @path: file to get attributes from
57 * @stat: structure to return attributes in
58 * @request_mask: STATX_xxx flags indicating what the caller wants
59 * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
61 * Get attributes without calling security_inode_getattr.
63 * Currently the only caller other than vfs_getattr is internal to the
64 * filehandle lookup code, which uses only the inode number and returns no
65 * attributes to any user. Any other code probably wants vfs_getattr.
67 int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
68 u32 request_mask, unsigned int query_flags)
70 struct inode *inode = d_backing_inode(path->dentry);
72 memset(stat, 0, sizeof(*stat));
73 stat->result_mask |= STATX_BASIC_STATS;
74 query_flags &= KSTAT_QUERY_FLAGS;
76 /* allow the fs to override these if it really wants to */
77 /* SB_NOATIME means filesystem supplies dummy atime value */
78 if (inode->i_sb->s_flags & SB_NOATIME)
79 stat->result_mask &= ~STATX_ATIME;
80 if (IS_AUTOMOUNT(inode))
81 stat->attributes |= STATX_ATTR_AUTOMOUNT;
83 if (inode->i_op->getattr)
84 return inode->i_op->getattr(path, stat, request_mask,
87 generic_fillattr(inode, stat);
90 EXPORT_SYMBOL(vfs_getattr_nosec);
93 * vfs_getattr - Get the enhanced basic attributes of a file
94 * @path: The file of interest
95 * @stat: Where to return the statistics
96 * @request_mask: STATX_xxx flags indicating what the caller wants
97 * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
99 * Ask the filesystem for a file's attributes. The caller must indicate in
100 * request_mask and query_flags to indicate what they want.
102 * If the file is remote, the filesystem can be forced to update the attributes
103 * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
104 * suppress the update by passing AT_STATX_DONT_SYNC.
106 * Bits must have been set in request_mask to indicate which attributes the
107 * caller wants retrieving. Any such attribute not requested may be returned
108 * anyway, but the value may be approximate, and, if remote, may not have been
109 * synchronised with the server.
111 * 0 will be returned on success, and a -ve error code if unsuccessful.
113 int vfs_getattr(const struct path *path, struct kstat *stat,
114 u32 request_mask, unsigned int query_flags)
118 retval = security_inode_getattr(path);
121 return vfs_getattr_nosec(path, stat, request_mask, query_flags);
123 EXPORT_SYMBOL(vfs_getattr);
126 * vfs_statx_fd - Get the enhanced basic attributes by file descriptor
127 * @fd: The file descriptor referring to the file of interest
128 * @stat: The result structure to fill in.
129 * @request_mask: STATX_xxx flags indicating what the caller wants
130 * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
132 * This function is a wrapper around vfs_getattr(). The main difference is
133 * that it uses a file descriptor to determine the file location.
135 * 0 will be returned on success, and a -ve error code if unsuccessful.
137 int vfs_statx_fd(unsigned int fd, struct kstat *stat,
138 u32 request_mask, unsigned int query_flags)
143 if (query_flags & ~KSTAT_QUERY_FLAGS)
148 error = vfs_getattr(&f.file->f_path, stat,
149 request_mask, query_flags);
154 EXPORT_SYMBOL(vfs_statx_fd);
156 static inline unsigned vfs_stat_set_lookup_flags(unsigned *lookup_flags,
159 if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
160 AT_EMPTY_PATH | KSTAT_QUERY_FLAGS)) != 0)
163 *lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
164 if (flags & AT_SYMLINK_NOFOLLOW)
165 *lookup_flags &= ~LOOKUP_FOLLOW;
166 if (flags & AT_NO_AUTOMOUNT)
167 *lookup_flags &= ~LOOKUP_AUTOMOUNT;
168 if (flags & AT_EMPTY_PATH)
169 *lookup_flags |= LOOKUP_EMPTY;
175 * vfs_statx - Get basic and extra attributes by filename
176 * @dfd: A file descriptor representing the base dir for a relative filename
177 * @filename: The name of the file of interest
178 * @flags: Flags to control the query
179 * @stat: The result structure to fill in.
180 * @request_mask: STATX_xxx flags indicating what the caller wants
182 * This function is a wrapper around vfs_getattr(). The main difference is
183 * that it uses a filename and base directory to determine the file location.
184 * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
185 * at the given name from being referenced.
187 * 0 will be returned on success, and a -ve error code if unsuccessful.
189 int vfs_statx(int dfd, const char __user *filename, int flags,
190 struct kstat *stat, u32 request_mask)
194 unsigned lookup_flags;
196 if (vfs_stat_set_lookup_flags(&lookup_flags, flags))
199 error = user_path_at(dfd, filename, lookup_flags, &path);
203 error = vfs_getattr(&path, stat, request_mask, flags);
204 stat->mnt_id = real_mount(path.mnt)->mnt_id;
205 stat->result_mask |= STATX_MNT_ID;
206 if (path.mnt->mnt_root == path.dentry)
207 stat->attributes |= STATX_ATTR_MOUNT_ROOT;
208 stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
210 if (retry_estale(error, lookup_flags)) {
211 lookup_flags |= LOOKUP_REVAL;
217 EXPORT_SYMBOL(vfs_statx);
220 #ifdef __ARCH_WANT_OLD_STAT
223 * For backward compatibility? Maybe this should be moved
224 * into arch/i386 instead?
226 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
228 static int warncount = 5;
229 struct __old_kernel_stat tmp;
233 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
235 } else if (warncount < 0) {
236 /* it's laughable, but... */
240 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
241 tmp.st_dev = old_encode_dev(stat->dev);
242 tmp.st_ino = stat->ino;
243 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
245 tmp.st_mode = stat->mode;
246 tmp.st_nlink = stat->nlink;
247 if (tmp.st_nlink != stat->nlink)
249 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
250 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
251 tmp.st_rdev = old_encode_dev(stat->rdev);
252 #if BITS_PER_LONG == 32
253 if (stat->size > MAX_NON_LFS)
256 tmp.st_size = stat->size;
257 tmp.st_atime = stat->atime.tv_sec;
258 tmp.st_mtime = stat->mtime.tv_sec;
259 tmp.st_ctime = stat->ctime.tv_sec;
260 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
263 SYSCALL_DEFINE2(stat, const char __user *, filename,
264 struct __old_kernel_stat __user *, statbuf)
269 error = vfs_stat(filename, &stat);
273 return cp_old_stat(&stat, statbuf);
276 SYSCALL_DEFINE2(lstat, const char __user *, filename,
277 struct __old_kernel_stat __user *, statbuf)
282 error = vfs_lstat(filename, &stat);
286 return cp_old_stat(&stat, statbuf);
289 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
292 int error = vfs_fstat(fd, &stat);
295 error = cp_old_stat(&stat, statbuf);
300 #endif /* __ARCH_WANT_OLD_STAT */
302 #ifdef __ARCH_WANT_NEW_STAT
304 #if BITS_PER_LONG == 32
305 # define choose_32_64(a,b) a
307 # define choose_32_64(a,b) b
310 #define valid_dev(x) choose_32_64(old_valid_dev(x),true)
311 #define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)
313 #ifndef INIT_STRUCT_STAT_PADDING
314 # define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
317 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
321 if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))
323 #if BITS_PER_LONG == 32
324 if (stat->size > MAX_NON_LFS)
328 INIT_STRUCT_STAT_PADDING(tmp);
329 tmp.st_dev = encode_dev(stat->dev);
330 tmp.st_ino = stat->ino;
331 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
333 tmp.st_mode = stat->mode;
334 tmp.st_nlink = stat->nlink;
335 if (tmp.st_nlink != stat->nlink)
337 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
338 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
339 tmp.st_rdev = encode_dev(stat->rdev);
340 tmp.st_size = stat->size;
341 tmp.st_atime = stat->atime.tv_sec;
342 tmp.st_mtime = stat->mtime.tv_sec;
343 tmp.st_ctime = stat->ctime.tv_sec;
344 #ifdef STAT_HAVE_NSEC
345 tmp.st_atime_nsec = stat->atime.tv_nsec;
346 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
347 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
349 tmp.st_blocks = stat->blocks;
350 tmp.st_blksize = stat->blksize;
351 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
354 SYSCALL_DEFINE2(newstat, const char __user *, filename,
355 struct stat __user *, statbuf)
358 int error = vfs_stat(filename, &stat);
362 return cp_new_stat(&stat, statbuf);
365 SYSCALL_DEFINE2(newlstat, const char __user *, filename,
366 struct stat __user *, statbuf)
371 error = vfs_lstat(filename, &stat);
375 return cp_new_stat(&stat, statbuf);
378 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
379 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
380 struct stat __user *, statbuf, int, flag)
385 error = vfs_fstatat(dfd, filename, &stat, flag);
388 return cp_new_stat(&stat, statbuf);
392 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
395 int error = vfs_fstat(fd, &stat);
398 error = cp_new_stat(&stat, statbuf);
404 static int do_readlinkat(int dfd, const char __user *pathname,
405 char __user *buf, int bufsiz)
410 unsigned int lookup_flags = LOOKUP_EMPTY;
416 error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
418 struct inode *inode = d_backing_inode(path.dentry);
420 error = empty ? -ENOENT : -EINVAL;
422 * AFS mountpoints allow readlink(2) but are not symlinks
424 if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
425 error = security_inode_readlink(path.dentry);
428 error = vfs_readlink(path.dentry, buf, bufsiz);
432 if (retry_estale(error, lookup_flags)) {
433 lookup_flags |= LOOKUP_REVAL;
440 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
441 char __user *, buf, int, bufsiz)
443 return do_readlinkat(dfd, pathname, buf, bufsiz);
446 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
449 return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
453 /* ---------- LFS-64 ----------- */
454 #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
456 #ifndef INIT_STRUCT_STAT64_PADDING
457 # define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
460 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
464 INIT_STRUCT_STAT64_PADDING(tmp);
466 /* mips has weird padding, so we don't get 64 bits there */
467 tmp.st_dev = new_encode_dev(stat->dev);
468 tmp.st_rdev = new_encode_dev(stat->rdev);
470 tmp.st_dev = huge_encode_dev(stat->dev);
471 tmp.st_rdev = huge_encode_dev(stat->rdev);
473 tmp.st_ino = stat->ino;
474 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
476 #ifdef STAT64_HAS_BROKEN_ST_INO
477 tmp.__st_ino = stat->ino;
479 tmp.st_mode = stat->mode;
480 tmp.st_nlink = stat->nlink;
481 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
482 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
483 tmp.st_atime = stat->atime.tv_sec;
484 tmp.st_atime_nsec = stat->atime.tv_nsec;
485 tmp.st_mtime = stat->mtime.tv_sec;
486 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
487 tmp.st_ctime = stat->ctime.tv_sec;
488 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
489 tmp.st_size = stat->size;
490 tmp.st_blocks = stat->blocks;
491 tmp.st_blksize = stat->blksize;
492 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
495 SYSCALL_DEFINE2(stat64, const char __user *, filename,
496 struct stat64 __user *, statbuf)
499 int error = vfs_stat(filename, &stat);
502 error = cp_new_stat64(&stat, statbuf);
507 SYSCALL_DEFINE2(lstat64, const char __user *, filename,
508 struct stat64 __user *, statbuf)
511 int error = vfs_lstat(filename, &stat);
514 error = cp_new_stat64(&stat, statbuf);
519 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
522 int error = vfs_fstat(fd, &stat);
525 error = cp_new_stat64(&stat, statbuf);
530 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
531 struct stat64 __user *, statbuf, int, flag)
536 error = vfs_fstatat(dfd, filename, &stat, flag);
539 return cp_new_stat64(&stat, statbuf);
541 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
543 static noinline_for_stack int
544 cp_statx(const struct kstat *stat, struct statx __user *buffer)
548 memset(&tmp, 0, sizeof(tmp));
550 tmp.stx_mask = stat->result_mask;
551 tmp.stx_blksize = stat->blksize;
552 tmp.stx_attributes = stat->attributes;
553 tmp.stx_nlink = stat->nlink;
554 tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
555 tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
556 tmp.stx_mode = stat->mode;
557 tmp.stx_ino = stat->ino;
558 tmp.stx_size = stat->size;
559 tmp.stx_blocks = stat->blocks;
560 tmp.stx_attributes_mask = stat->attributes_mask;
561 tmp.stx_atime.tv_sec = stat->atime.tv_sec;
562 tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
563 tmp.stx_btime.tv_sec = stat->btime.tv_sec;
564 tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
565 tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
566 tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
567 tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
568 tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
569 tmp.stx_rdev_major = MAJOR(stat->rdev);
570 tmp.stx_rdev_minor = MINOR(stat->rdev);
571 tmp.stx_dev_major = MAJOR(stat->dev);
572 tmp.stx_dev_minor = MINOR(stat->dev);
573 tmp.stx_mnt_id = stat->mnt_id;
575 return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
578 int do_statx(int dfd, const char __user *filename, unsigned flags,
579 unsigned int mask, struct statx __user *buffer)
584 if (mask & STATX__RESERVED)
586 if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
589 error = vfs_statx(dfd, filename, flags, &stat, mask);
593 return cp_statx(&stat, buffer);
597 * sys_statx - System call to get enhanced stats
598 * @dfd: Base directory to pathwalk from *or* fd to stat.
599 * @filename: File to stat or "" with AT_EMPTY_PATH
600 * @flags: AT_* flags to control pathwalk.
601 * @mask: Parts of statx struct actually required.
602 * @buffer: Result buffer.
604 * Note that fstat() can be emulated by setting dfd to the fd of interest,
605 * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
607 SYSCALL_DEFINE5(statx,
608 int, dfd, const char __user *, filename, unsigned, flags,
610 struct statx __user *, buffer)
612 return do_statx(dfd, filename, flags, mask, buffer);
616 static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
618 struct compat_stat tmp;
620 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
623 memset(&tmp, 0, sizeof(tmp));
624 tmp.st_dev = old_encode_dev(stat->dev);
625 tmp.st_ino = stat->ino;
626 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
628 tmp.st_mode = stat->mode;
629 tmp.st_nlink = stat->nlink;
630 if (tmp.st_nlink != stat->nlink)
632 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
633 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
634 tmp.st_rdev = old_encode_dev(stat->rdev);
635 if ((u64) stat->size > MAX_NON_LFS)
637 tmp.st_size = stat->size;
638 tmp.st_atime = stat->atime.tv_sec;
639 tmp.st_atime_nsec = stat->atime.tv_nsec;
640 tmp.st_mtime = stat->mtime.tv_sec;
641 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
642 tmp.st_ctime = stat->ctime.tv_sec;
643 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
644 tmp.st_blocks = stat->blocks;
645 tmp.st_blksize = stat->blksize;
646 return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
649 COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
650 struct compat_stat __user *, statbuf)
655 error = vfs_stat(filename, &stat);
658 return cp_compat_stat(&stat, statbuf);
661 COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
662 struct compat_stat __user *, statbuf)
667 error = vfs_lstat(filename, &stat);
670 return cp_compat_stat(&stat, statbuf);
673 #ifndef __ARCH_WANT_STAT64
674 COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
675 const char __user *, filename,
676 struct compat_stat __user *, statbuf, int, flag)
681 error = vfs_fstatat(dfd, filename, &stat, flag);
684 return cp_compat_stat(&stat, statbuf);
688 COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
689 struct compat_stat __user *, statbuf)
692 int error = vfs_fstat(fd, &stat);
695 error = cp_compat_stat(&stat, statbuf);
700 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
701 void __inode_add_bytes(struct inode *inode, loff_t bytes)
703 inode->i_blocks += bytes >> 9;
705 inode->i_bytes += bytes;
706 if (inode->i_bytes >= 512) {
708 inode->i_bytes -= 512;
711 EXPORT_SYMBOL(__inode_add_bytes);
713 void inode_add_bytes(struct inode *inode, loff_t bytes)
715 spin_lock(&inode->i_lock);
716 __inode_add_bytes(inode, bytes);
717 spin_unlock(&inode->i_lock);
720 EXPORT_SYMBOL(inode_add_bytes);
722 void __inode_sub_bytes(struct inode *inode, loff_t bytes)
724 inode->i_blocks -= bytes >> 9;
726 if (inode->i_bytes < bytes) {
728 inode->i_bytes += 512;
730 inode->i_bytes -= bytes;
733 EXPORT_SYMBOL(__inode_sub_bytes);
735 void inode_sub_bytes(struct inode *inode, loff_t bytes)
737 spin_lock(&inode->i_lock);
738 __inode_sub_bytes(inode, bytes);
739 spin_unlock(&inode->i_lock);
742 EXPORT_SYMBOL(inode_sub_bytes);
744 loff_t inode_get_bytes(struct inode *inode)
748 spin_lock(&inode->i_lock);
749 ret = __inode_get_bytes(inode);
750 spin_unlock(&inode->i_lock);
754 EXPORT_SYMBOL(inode_get_bytes);
756 void inode_set_bytes(struct inode *inode, loff_t bytes)
758 /* Caller is here responsible for sufficient locking
759 * (ie. inode->i_lock) */
760 inode->i_blocks = bytes >> 9;
761 inode->i_bytes = bytes & 511;
764 EXPORT_SYMBOL(inode_set_bytes);