fs/stat.c

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