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 (KSTAT_QUERY_FLAGS)
  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 &= KSTAT_QUERY_FLAGS;
  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         if (IS_AUTOMOUNT(inode))
  81                 stat->attributes |= STATX_ATTR_AUTOMOUNT;
  82
  83         if (IS_DAX(inode))
  84                 stat->attributes |= STATX_ATTR_DAX;
  85
  86         if (inode->i_op->getattr)
  87                 return inode->i_op->getattr(path, stat, request_mask,
  88                                             query_flags);
  89
  90         generic_fillattr(inode, stat);
  91         return 0;
  92 }
  93 EXPORT_SYMBOL(vfs_getattr_nosec);
  94
  95 /*
  96  * vfs_getattr - Get the enhanced basic attributes of a file
  97  * @path: The file of interest
  98  * @stat: Where to return the statistics
  99  * @request_mask: STATX_xxx flags indicating what the caller wants
 100  * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
 101  *
 102  * Ask the filesystem for a file's attributes.  The caller must indicate in
 103  * request_mask and query_flags to indicate what they want.
 104  *
 105  * If the file is remote, the filesystem can be forced to update the attributes
 106  * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
 107  * suppress the update by passing AT_STATX_DONT_SYNC.
 108  *
 109  * Bits must have been set in request_mask to indicate which attributes the
 110  * caller wants retrieving.  Any such attribute not requested may be returned
 111  * anyway, but the value may be approximate, and, if remote, may not have been
 112  * synchronised with the server.
 113  *
 114  * 0 will be returned on success, and a -ve error code if unsuccessful.
 115  */
 116 int vfs_getattr(const struct path *path, struct kstat *stat,
 117                 u32 request_mask, unsigned int query_flags)
 118 {
 119         int retval;
 120
 121         retval = security_inode_getattr(path);
 122         if (retval)
 123                 return retval;
 124         return vfs_getattr_nosec(path, stat, request_mask, query_flags);
 125 }
 126 EXPORT_SYMBOL(vfs_getattr);
 127
 128 /**
 129  * vfs_statx_fd - Get the enhanced basic attributes by file descriptor
 130  * @fd: The file descriptor referring to the file of interest
 131  * @stat: The result structure to fill in.
 132  * @request_mask: STATX_xxx flags indicating what the caller wants
 133  * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
 134  *
 135  * This function is a wrapper around vfs_getattr().  The main difference is
 136  * that it uses a file descriptor to determine the file location.
 137  *
 138  * 0 will be returned on success, and a -ve error code if unsuccessful.
 139  */
 140 int vfs_statx_fd(unsigned int fd, struct kstat *stat,
 141                  u32 request_mask, unsigned int query_flags)
 142 {
 143         struct fd f;
 144         int error = -EBADF;
 145
 146         if (query_flags & ~KSTAT_QUERY_FLAGS)
 147                 return -EINVAL;
 148
 149         f = fdget_raw(fd);
 150         if (f.file) {
 151                 error = vfs_getattr(&f.file->f_path, stat,
 152                                     request_mask, query_flags);
 153                 fdput(f);
 154         }
 155         return error;
 156 }
 157 EXPORT_SYMBOL(vfs_statx_fd);
 158
 159 static inline unsigned vfs_stat_set_lookup_flags(unsigned *lookup_flags,
 160                                                  int flags)
 161 {
 162         if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
 163                        AT_EMPTY_PATH | KSTAT_QUERY_FLAGS)) != 0)
 164                 return -EINVAL;
 165
 166         *lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
 167         if (flags & AT_SYMLINK_NOFOLLOW)
 168                 *lookup_flags &= ~LOOKUP_FOLLOW;
 169         if (flags & AT_NO_AUTOMOUNT)
 170                 *lookup_flags &= ~LOOKUP_AUTOMOUNT;
 171         if (flags & AT_EMPTY_PATH)
 172                 *lookup_flags |= LOOKUP_EMPTY;
 173
 174         return 0;
 175 }
 176
 177 /**
 178  * vfs_statx - Get basic and extra attributes by filename
 179  * @dfd: A file descriptor representing the base dir for a relative filename
 180  * @filename: The name of the file of interest
 181  * @flags: Flags to control the query
 182  * @stat: The result structure to fill in.
 183  * @request_mask: STATX_xxx flags indicating what the caller wants
 184  *
 185  * This function is a wrapper around vfs_getattr().  The main difference is
 186  * that it uses a filename and base directory to determine the file location.
 187  * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
 188  * at the given name from being referenced.
 189  *
 190  * 0 will be returned on success, and a -ve error code if unsuccessful.
 191  */
 192 int vfs_statx(int dfd, const char __user *filename, int flags,
 193               struct kstat *stat, u32 request_mask)
 194 {
 195         struct path path;
 196         int error = -EINVAL;
 197         unsigned lookup_flags;
 198
 199         if (vfs_stat_set_lookup_flags(&lookup_flags, flags))
 200                 return -EINVAL;
 201 retry:
 202         error = user_path_at(dfd, filename, lookup_flags, &path);
 203         if (error)
 204                 goto out;
 205
 206         error = vfs_getattr(&path, stat, request_mask, flags);
 207         stat->mnt_id = real_mount(path.mnt)->mnt_id;
 208         stat->result_mask |= STATX_MNT_ID;
 209         if (path.mnt->mnt_root == path.dentry)
 210                 stat->attributes |= STATX_ATTR_MOUNT_ROOT;
 211         stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT;
 212         path_put(&path);
 213         if (retry_estale(error, lookup_flags)) {
 214                 lookup_flags |= LOOKUP_REVAL;
 215                 goto retry;
 216         }
 217 out:
 218         return error;
 219 }
 220 EXPORT_SYMBOL(vfs_statx);
 221
 222
 223 #ifdef __ARCH_WANT_OLD_STAT
 224
 225 /*
 226  * For backward compatibility?  Maybe this should be moved
 227  * into arch/i386 instead?
 228  */
 229 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
 230 {
 231         static int warncount = 5;
 232         struct __old_kernel_stat tmp;
 233
 234         if (warncount > 0) {
 235                 warncount--;
 236                 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
 237                         current->comm);
 238         } else if (warncount < 0) {
 239                 /* it's laughable, but... */
 240                 warncount = 0;
 241         }
 242
 243         memset(&tmp, 0, sizeof(struct __old_kernel_stat));
 244         tmp.st_dev = old_encode_dev(stat->dev);
 245         tmp.st_ino = stat->ino;
 246         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 247                 return -EOVERFLOW;
 248         tmp.st_mode = stat->mode;
 249         tmp.st_nlink = stat->nlink;
 250         if (tmp.st_nlink != stat->nlink)
 251                 return -EOVERFLOW;
 252         SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
 253         SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 254         tmp.st_rdev = old_encode_dev(stat->rdev);
 255 #if BITS_PER_LONG == 32
 256         if (stat->size > MAX_NON_LFS)
 257                 return -EOVERFLOW;
 258 #endif
 259         tmp.st_size = stat->size;
 260         tmp.st_atime = stat->atime.tv_sec;
 261         tmp.st_mtime = stat->mtime.tv_sec;
 262         tmp.st_ctime = stat->ctime.tv_sec;
 263         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 264 }
 265
 266 SYSCALL_DEFINE2(stat, const char __user *, filename,
 267                 struct __old_kernel_stat __user *, statbuf)
 268 {
 269         struct kstat stat;
 270         int error;
 271
 272         error = vfs_stat(filename, &stat);
 273         if (error)
 274                 return error;
 275
 276         return cp_old_stat(&stat, statbuf);
 277 }
 278
 279 SYSCALL_DEFINE2(lstat, const char __user *, filename,
 280                 struct __old_kernel_stat __user *, statbuf)
 281 {
 282         struct kstat stat;
 283         int error;
 284
 285         error = vfs_lstat(filename, &stat);
 286         if (error)
 287                 return error;
 288
 289         return cp_old_stat(&stat, statbuf);
 290 }
 291
 292 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
 293 {
 294         struct kstat stat;
 295         int error = vfs_fstat(fd, &stat);
 296
 297         if (!error)
 298                 error = cp_old_stat(&stat, statbuf);
 299
 300         return error;
 301 }
 302
 303 #endif /* __ARCH_WANT_OLD_STAT */
 304
 305 #ifdef __ARCH_WANT_NEW_STAT
 306
 307 #if BITS_PER_LONG == 32
 308 #  define choose_32_64(a,b) a
 309 #else
 310 #  define choose_32_64(a,b) b
 311 #endif
 312
 313 #define valid_dev(x)  choose_32_64(old_valid_dev(x),true)
 314 #define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x)
 315
 316 #ifndef INIT_STRUCT_STAT_PADDING
 317 #  define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
 318 #endif
 319
 320 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 321 {
 322         struct stat tmp;
 323
 324         if (!valid_dev(stat->dev) || !valid_dev(stat->rdev))
 325                 return -EOVERFLOW;
 326 #if BITS_PER_LONG == 32
 327         if (stat->size > MAX_NON_LFS)
 328                 return -EOVERFLOW;
 329 #endif
 330
 331         INIT_STRUCT_STAT_PADDING(tmp);
 332         tmp.st_dev = encode_dev(stat->dev);
 333         tmp.st_ino = stat->ino;
 334         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 335                 return -EOVERFLOW;
 336         tmp.st_mode = stat->mode;
 337         tmp.st_nlink = stat->nlink;
 338         if (tmp.st_nlink != stat->nlink)
 339                 return -EOVERFLOW;
 340         SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
 341         SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 342         tmp.st_rdev = encode_dev(stat->rdev);
 343         tmp.st_size = stat->size;
 344         tmp.st_atime = stat->atime.tv_sec;
 345         tmp.st_mtime = stat->mtime.tv_sec;
 346         tmp.st_ctime = stat->ctime.tv_sec;
 347 #ifdef STAT_HAVE_NSEC
 348         tmp.st_atime_nsec = stat->atime.tv_nsec;
 349         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 350         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 351 #endif
 352         tmp.st_blocks = stat->blocks;
 353         tmp.st_blksize = stat->blksize;
 354         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 355 }
 356
 357 SYSCALL_DEFINE2(newstat, const char __user *, filename,
 358                 struct stat __user *, statbuf)
 359 {
 360         struct kstat stat;
 361         int error = vfs_stat(filename, &stat);
 362
 363         if (error)
 364                 return error;
 365         return cp_new_stat(&stat, statbuf);
 366 }
 367
 368 SYSCALL_DEFINE2(newlstat, const char __user *, filename,
 369                 struct stat __user *, statbuf)
 370 {
 371         struct kstat stat;
 372         int error;
 373
 374         error = vfs_lstat(filename, &stat);
 375         if (error)
 376                 return error;
 377
 378         return cp_new_stat(&stat, statbuf);
 379 }
 380
 381 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
 382 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
 383                 struct stat __user *, statbuf, int, flag)
 384 {
 385         struct kstat stat;
 386         int error;
 387
 388         error = vfs_fstatat(dfd, filename, &stat, flag);
 389         if (error)
 390                 return error;
 391         return cp_new_stat(&stat, statbuf);
 392 }
 393 #endif
 394
 395 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
 396 {
 397         struct kstat stat;
 398         int error = vfs_fstat(fd, &stat);
 399
 400         if (!error)
 401                 error = cp_new_stat(&stat, statbuf);
 402
 403         return error;
 404 }
 405 #endif
 406
 407 static int do_readlinkat(int dfd, const char __user *pathname,
 408                          char __user *buf, int bufsiz)
 409 {
 410         struct path path;
 411         int error;
 412         int empty = 0;
 413         unsigned int lookup_flags = LOOKUP_EMPTY;
 414
 415         if (bufsiz <= 0)
 416                 return -EINVAL;
 417
 418 retry:
 419         error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
 420         if (!error) {
 421                 struct inode *inode = d_backing_inode(path.dentry);
 422
 423                 error = empty ? -ENOENT : -EINVAL;
 424                 /*
 425                  * AFS mountpoints allow readlink(2) but are not symlinks
 426                  */
 427                 if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
 428                         error = security_inode_readlink(path.dentry);
 429                         if (!error) {
 430                                 touch_atime(&path);
 431                                 error = vfs_readlink(path.dentry, buf, bufsiz);
 432                         }
 433                 }
 434                 path_put(&path);
 435                 if (retry_estale(error, lookup_flags)) {
 436                         lookup_flags |= LOOKUP_REVAL;
 437                         goto retry;
 438                 }
 439         }
 440         return error;
 441 }
 442
 443 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 444                 char __user *, buf, int, bufsiz)
 445 {
 446         return do_readlinkat(dfd, pathname, buf, bufsiz);
 447 }
 448
 449 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
 450                 int, bufsiz)
 451 {
 452         return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
 453 }
 454
 455
 456 /* ---------- LFS-64 ----------- */
 457 #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
 458
 459 #ifndef INIT_STRUCT_STAT64_PADDING
 460 #  define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
 461 #endif
 462
 463 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
 464 {
 465         struct stat64 tmp;
 466
 467         INIT_STRUCT_STAT64_PADDING(tmp);
 468 #ifdef CONFIG_MIPS
 469         /* mips has weird padding, so we don't get 64 bits there */
 470         tmp.st_dev = new_encode_dev(stat->dev);
 471         tmp.st_rdev = new_encode_dev(stat->rdev);
 472 #else
 473         tmp.st_dev = huge_encode_dev(stat->dev);
 474         tmp.st_rdev = huge_encode_dev(stat->rdev);
 475 #endif
 476         tmp.st_ino = stat->ino;
 477         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 478                 return -EOVERFLOW;
 479 #ifdef STAT64_HAS_BROKEN_ST_INO
 480         tmp.__st_ino = stat->ino;
 481 #endif
 482         tmp.st_mode = stat->mode;
 483         tmp.st_nlink = stat->nlink;
 484         tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
 485         tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 486         tmp.st_atime = stat->atime.tv_sec;
 487         tmp.st_atime_nsec = stat->atime.tv_nsec;
 488         tmp.st_mtime = stat->mtime.tv_sec;
 489         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 490         tmp.st_ctime = stat->ctime.tv_sec;
 491         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 492         tmp.st_size = stat->size;
 493         tmp.st_blocks = stat->blocks;
 494         tmp.st_blksize = stat->blksize;
 495         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 496 }
 497
 498 SYSCALL_DEFINE2(stat64, const char __user *, filename,
 499                 struct stat64 __user *, statbuf)
 500 {
 501         struct kstat stat;
 502         int error = vfs_stat(filename, &stat);
 503
 504         if (!error)
 505                 error = cp_new_stat64(&stat, statbuf);
 506
 507         return error;
 508 }
 509
 510 SYSCALL_DEFINE2(lstat64, const char __user *, filename,
 511                 struct stat64 __user *, statbuf)
 512 {
 513         struct kstat stat;
 514         int error = vfs_lstat(filename, &stat);
 515
 516         if (!error)
 517                 error = cp_new_stat64(&stat, statbuf);
 518
 519         return error;
 520 }
 521
 522 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
 523 {
 524         struct kstat stat;
 525         int error = vfs_fstat(fd, &stat);
 526
 527         if (!error)
 528                 error = cp_new_stat64(&stat, statbuf);
 529
 530         return error;
 531 }
 532
 533 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
 534                 struct stat64 __user *, statbuf, int, flag)
 535 {
 536         struct kstat stat;
 537         int error;
 538
 539         error = vfs_fstatat(dfd, filename, &stat, flag);
 540         if (error)
 541                 return error;
 542         return cp_new_stat64(&stat, statbuf);
 543 }
 544 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
 545
 546 static noinline_for_stack int
 547 cp_statx(const struct kstat *stat, struct statx __user *buffer)
 548 {
 549         struct statx tmp;
 550
 551         memset(&tmp, 0, sizeof(tmp));
 552
 553         tmp.stx_mask = stat->result_mask;
 554         tmp.stx_blksize = stat->blksize;
 555         tmp.stx_attributes = stat->attributes;
 556         tmp.stx_nlink = stat->nlink;
 557         tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
 558         tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
 559         tmp.stx_mode = stat->mode;
 560         tmp.stx_ino = stat->ino;
 561         tmp.stx_size = stat->size;
 562         tmp.stx_blocks = stat->blocks;
 563         tmp.stx_attributes_mask = stat->attributes_mask;
 564         tmp.stx_atime.tv_sec = stat->atime.tv_sec;
 565         tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
 566         tmp.stx_btime.tv_sec = stat->btime.tv_sec;
 567         tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
 568         tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
 569         tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
 570         tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
 571         tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
 572         tmp.stx_rdev_major = MAJOR(stat->rdev);
 573         tmp.stx_rdev_minor = MINOR(stat->rdev);
 574         tmp.stx_dev_major = MAJOR(stat->dev);
 575         tmp.stx_dev_minor = MINOR(stat->dev);
 576         tmp.stx_mnt_id = stat->mnt_id;
 577
 578         return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 579 }
 580
 581 int do_statx(int dfd, const char __user *filename, unsigned flags,
 582              unsigned int mask, struct statx __user *buffer)
 583 {
 584         struct kstat stat;
 585         int error;
 586
 587         if (mask & STATX__RESERVED)
 588                 return -EINVAL;
 589         if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
 590                 return -EINVAL;
 591
 592         error = vfs_statx(dfd, filename, flags, &stat, mask);
 593         if (error)
 594                 return error;
 595
 596         return cp_statx(&stat, buffer);
 597 }
 598
 599 /**
 600  * sys_statx - System call to get enhanced stats
 601  * @dfd: Base directory to pathwalk from *or* fd to stat.
 602  * @filename: File to stat or "" with AT_EMPTY_PATH
 603  * @flags: AT_* flags to control pathwalk.
 604  * @mask: Parts of statx struct actually required.
 605  * @buffer: Result buffer.
 606  *
 607  * Note that fstat() can be emulated by setting dfd to the fd of interest,
 608  * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
 609  */
 610 SYSCALL_DEFINE5(statx,
 611                 int, dfd, const char __user *, filename, unsigned, flags,
 612                 unsigned int, mask,
 613                 struct statx __user *, buffer)
 614 {
 615         return do_statx(dfd, filename, flags, mask, buffer);
 616 }
 617
 618 #ifdef CONFIG_COMPAT
 619 static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
 620 {
 621         struct compat_stat tmp;
 622
 623         if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
 624                 return -EOVERFLOW;
 625
 626         memset(&tmp, 0, sizeof(tmp));
 627         tmp.st_dev = old_encode_dev(stat->dev);
 628         tmp.st_ino = stat->ino;
 629         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 630                 return -EOVERFLOW;
 631         tmp.st_mode = stat->mode;
 632         tmp.st_nlink = stat->nlink;
 633         if (tmp.st_nlink != stat->nlink)
 634                 return -EOVERFLOW;
 635         SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
 636         SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 637         tmp.st_rdev = old_encode_dev(stat->rdev);
 638         if ((u64) stat->size > MAX_NON_LFS)
 639                 return -EOVERFLOW;
 640         tmp.st_size = stat->size;
 641         tmp.st_atime = stat->atime.tv_sec;
 642         tmp.st_atime_nsec = stat->atime.tv_nsec;
 643         tmp.st_mtime = stat->mtime.tv_sec;
 644         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 645         tmp.st_ctime = stat->ctime.tv_sec;
 646         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 647         tmp.st_blocks = stat->blocks;
 648         tmp.st_blksize = stat->blksize;
 649         return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
 650 }
 651
 652 COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
 653                        struct compat_stat __user *, statbuf)
 654 {
 655         struct kstat stat;
 656         int error;
 657
 658         error = vfs_stat(filename, &stat);
 659         if (error)
 660                 return error;
 661         return cp_compat_stat(&stat, statbuf);
 662 }
 663
 664 COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
 665                        struct compat_stat __user *, statbuf)
 666 {
 667         struct kstat stat;
 668         int error;
 669
 670         error = vfs_lstat(filename, &stat);
 671         if (error)
 672                 return error;
 673         return cp_compat_stat(&stat, statbuf);
 674 }
 675
 676 #ifndef __ARCH_WANT_STAT64
 677 COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
 678                        const char __user *, filename,
 679                        struct compat_stat __user *, statbuf, int, flag)
 680 {
 681         struct kstat stat;
 682         int error;
 683
 684         error = vfs_fstatat(dfd, filename, &stat, flag);
 685         if (error)
 686                 return error;
 687         return cp_compat_stat(&stat, statbuf);
 688 }
 689 #endif
 690
 691 COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
 692                        struct compat_stat __user *, statbuf)
 693 {
 694         struct kstat stat;
 695         int error = vfs_fstat(fd, &stat);
 696
 697         if (!error)
 698                 error = cp_compat_stat(&stat, statbuf);
 699         return error;
 700 }
 701 #endif
 702
 703 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
 704 void __inode_add_bytes(struct inode *inode, loff_t bytes)
 705 {
 706         inode->i_blocks += bytes >> 9;
 707         bytes &= 511;
 708         inode->i_bytes += bytes;
 709         if (inode->i_bytes >= 512) {
 710                 inode->i_blocks++;
 711                 inode->i_bytes -= 512;
 712         }
 713 }
 714 EXPORT_SYMBOL(__inode_add_bytes);
 715
 716 void inode_add_bytes(struct inode *inode, loff_t bytes)
 717 {
 718         spin_lock(&inode->i_lock);
 719         __inode_add_bytes(inode, bytes);
 720         spin_unlock(&inode->i_lock);
 721 }
 722
 723 EXPORT_SYMBOL(inode_add_bytes);
 724
 725 void __inode_sub_bytes(struct inode *inode, loff_t bytes)
 726 {
 727         inode->i_blocks -= bytes >> 9;
 728         bytes &= 511;
 729         if (inode->i_bytes < bytes) {
 730                 inode->i_blocks--;
 731                 inode->i_bytes += 512;
 732         }
 733         inode->i_bytes -= bytes;
 734 }
 735
 736 EXPORT_SYMBOL(__inode_sub_bytes);
 737
 738 void inode_sub_bytes(struct inode *inode, loff_t bytes)
 739 {
 740         spin_lock(&inode->i_lock);
 741         __inode_sub_bytes(inode, bytes);
 742         spin_unlock(&inode->i_lock);
 743 }
 744
 745 EXPORT_SYMBOL(inode_sub_bytes);
 746
 747 loff_t inode_get_bytes(struct inode *inode)
 748 {
 749         loff_t ret;
 750
 751         spin_lock(&inode->i_lock);
 752         ret = __inode_get_bytes(inode);
 753         spin_unlock(&inode->i_lock);
 754         return ret;
 755 }
 756
 757 EXPORT_SYMBOL(inode_get_bytes);
 758
 759 void inode_set_bytes(struct inode *inode, loff_t bytes)
 760 {
 761         /* Caller is here responsible for sufficient locking
 762          * (ie. inode->i_lock) */
 763         inode->i_blocks = bytes >> 9;
 764         inode->i_bytes = bytes & 511;
 765 }
 766
 767 EXPORT_SYMBOL(inode_set_bytes);