| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * linux/fs/stat.c |
| 4 | * |
| 5 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 6 | */ |
| 7 | |
| 8 | #include <linux/blkdev.h> |
| 9 | #include <linux/export.h> |
| 10 | #include <linux/mm.h> |
| 11 | #include <linux/errno.h> |
| 12 | #include <linux/file.h> |
| 13 | #include <linux/highuid.h> |
| 14 | #include <linux/fs.h> |
| 15 | #include <linux/namei.h> |
| 16 | #include <linux/security.h> |
| 17 | #include <linux/cred.h> |
| 18 | #include <linux/syscalls.h> |
| 19 | #include <linux/pagemap.h> |
| 20 | #include <linux/compat.h> |
| 21 | #include <linux/iversion.h> |
| 22 | |
| 23 | #include <linux/uaccess.h> |
| 24 | #include <asm/unistd.h> |
| 25 | |
| 26 | #include "internal.h" |
| 27 | #include "mount.h" |
| 28 | |
| 29 | /** |
| 30 | * generic_fillattr - Fill in the basic attributes from the inode struct |
| 31 | * @idmap: idmap of the mount the inode was found from |
| 32 | * @request_mask: statx request_mask |
| 33 | * @inode: Inode to use as the source |
| 34 | * @stat: Where to fill in the attributes |
| 35 | * |
| 36 | * Fill in the basic attributes in the kstat structure from data that's to be |
| 37 | * found on the VFS inode structure. This is the default if no getattr inode |
| 38 | * operation is supplied. |
| 39 | * |
| 40 | * If the inode has been found through an idmapped mount the idmap of |
| 41 | * the vfsmount must be passed through @idmap. This function will then |
| 42 | * take care to map the inode according to @idmap before filling in the |
| 43 | * uid and gid filds. On non-idmapped mounts or if permission checking is to be |
| 44 | * performed on the raw inode simply pass @nop_mnt_idmap. |
| 45 | */ |
| 46 | void generic_fillattr(struct mnt_idmap *idmap, u32 request_mask, |
| 47 | struct inode *inode, struct kstat *stat) |
| 48 | { |
| 49 | vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode); |
| 50 | vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode); |
| 51 | |
| 52 | stat->dev = inode->i_sb->s_dev; |
| 53 | stat->ino = inode->i_ino; |
| 54 | stat->mode = inode->i_mode; |
| 55 | stat->nlink = inode->i_nlink; |
| 56 | stat->uid = vfsuid_into_kuid(vfsuid); |
| 57 | stat->gid = vfsgid_into_kgid(vfsgid); |
| 58 | stat->rdev = inode->i_rdev; |
| 59 | stat->size = i_size_read(inode); |
| 60 | stat->atime = inode_get_atime(inode); |
| 61 | stat->mtime = inode_get_mtime(inode); |
| 62 | stat->ctime = inode_get_ctime(inode); |
| 63 | stat->blksize = i_blocksize(inode); |
| 64 | stat->blocks = inode->i_blocks; |
| 65 | |
| 66 | if ((request_mask & STATX_CHANGE_COOKIE) && IS_I_VERSION(inode)) { |
| 67 | stat->result_mask |= STATX_CHANGE_COOKIE; |
| 68 | stat->change_cookie = inode_query_iversion(inode); |
| 69 | } |
| 70 | |
| 71 | } |
| 72 | EXPORT_SYMBOL(generic_fillattr); |
| 73 | |
| 74 | /** |
| 75 | * generic_fill_statx_attr - Fill in the statx attributes from the inode flags |
| 76 | * @inode: Inode to use as the source |
| 77 | * @stat: Where to fill in the attribute flags |
| 78 | * |
| 79 | * Fill in the STATX_ATTR_* flags in the kstat structure for properties of the |
| 80 | * inode that are published on i_flags and enforced by the VFS. |
| 81 | */ |
| 82 | void generic_fill_statx_attr(struct inode *inode, struct kstat *stat) |
| 83 | { |
| 84 | if (inode->i_flags & S_IMMUTABLE) |
| 85 | stat->attributes |= STATX_ATTR_IMMUTABLE; |
| 86 | if (inode->i_flags & S_APPEND) |
| 87 | stat->attributes |= STATX_ATTR_APPEND; |
| 88 | stat->attributes_mask |= KSTAT_ATTR_VFS_FLAGS; |
| 89 | } |
| 90 | EXPORT_SYMBOL(generic_fill_statx_attr); |
| 91 | |
| 92 | /** |
| 93 | * generic_fill_statx_atomic_writes - Fill in atomic writes statx attributes |
| 94 | * @stat: Where to fill in the attribute flags |
| 95 | * @unit_min: Minimum supported atomic write length in bytes |
| 96 | * @unit_max: Maximum supported atomic write length in bytes |
| 97 | * |
| 98 | * Fill in the STATX{_ATTR}_WRITE_ATOMIC flags in the kstat structure from |
| 99 | * atomic write unit_min and unit_max values. |
| 100 | */ |
| 101 | void generic_fill_statx_atomic_writes(struct kstat *stat, |
| 102 | unsigned int unit_min, |
| 103 | unsigned int unit_max) |
| 104 | { |
| 105 | /* Confirm that the request type is known */ |
| 106 | stat->result_mask |= STATX_WRITE_ATOMIC; |
| 107 | |
| 108 | /* Confirm that the file attribute type is known */ |
| 109 | stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC; |
| 110 | |
| 111 | if (unit_min) { |
| 112 | stat->atomic_write_unit_min = unit_min; |
| 113 | stat->atomic_write_unit_max = unit_max; |
| 114 | /* Initially only allow 1x segment */ |
| 115 | stat->atomic_write_segments_max = 1; |
| 116 | |
| 117 | /* Confirm atomic writes are actually supported */ |
| 118 | stat->attributes |= STATX_ATTR_WRITE_ATOMIC; |
| 119 | } |
| 120 | } |
| 121 | EXPORT_SYMBOL_GPL(generic_fill_statx_atomic_writes); |
| 122 | |
| 123 | /** |
| 124 | * vfs_getattr_nosec - getattr without security checks |
| 125 | * @path: file to get attributes from |
| 126 | * @stat: structure to return attributes in |
| 127 | * @request_mask: STATX_xxx flags indicating what the caller wants |
| 128 | * @query_flags: Query mode (AT_STATX_SYNC_TYPE) |
| 129 | * |
| 130 | * Get attributes without calling security_inode_getattr. |
| 131 | * |
| 132 | * Currently the only caller other than vfs_getattr is internal to the |
| 133 | * filehandle lookup code, which uses only the inode number and returns no |
| 134 | * attributes to any user. Any other code probably wants vfs_getattr. |
| 135 | */ |
| 136 | int vfs_getattr_nosec(const struct path *path, struct kstat *stat, |
| 137 | u32 request_mask, unsigned int query_flags) |
| 138 | { |
| 139 | struct mnt_idmap *idmap; |
| 140 | struct inode *inode = d_backing_inode(path->dentry); |
| 141 | |
| 142 | memset(stat, 0, sizeof(*stat)); |
| 143 | stat->result_mask |= STATX_BASIC_STATS; |
| 144 | query_flags &= AT_STATX_SYNC_TYPE; |
| 145 | |
| 146 | /* allow the fs to override these if it really wants to */ |
| 147 | /* SB_NOATIME means filesystem supplies dummy atime value */ |
| 148 | if (inode->i_sb->s_flags & SB_NOATIME) |
| 149 | stat->result_mask &= ~STATX_ATIME; |
| 150 | |
| 151 | /* |
| 152 | * Note: If you add another clause to set an attribute flag, please |
| 153 | * update attributes_mask below. |
| 154 | */ |
| 155 | if (IS_AUTOMOUNT(inode)) |
| 156 | stat->attributes |= STATX_ATTR_AUTOMOUNT; |
| 157 | |
| 158 | if (IS_DAX(inode)) |
| 159 | stat->attributes |= STATX_ATTR_DAX; |
| 160 | |
| 161 | stat->attributes_mask |= (STATX_ATTR_AUTOMOUNT | |
| 162 | STATX_ATTR_DAX); |
| 163 | |
| 164 | idmap = mnt_idmap(path->mnt); |
| 165 | if (inode->i_op->getattr) |
| 166 | return inode->i_op->getattr(idmap, path, stat, |
| 167 | request_mask, |
| 168 | query_flags | AT_GETATTR_NOSEC); |
| 169 | |
| 170 | generic_fillattr(idmap, request_mask, inode, stat); |
| 171 | return 0; |
| 172 | } |
| 173 | EXPORT_SYMBOL(vfs_getattr_nosec); |
| 174 | |
| 175 | /* |
| 176 | * vfs_getattr - Get the enhanced basic attributes of a file |
| 177 | * @path: The file of interest |
| 178 | * @stat: Where to return the statistics |
| 179 | * @request_mask: STATX_xxx flags indicating what the caller wants |
| 180 | * @query_flags: Query mode (AT_STATX_SYNC_TYPE) |
| 181 | * |
| 182 | * Ask the filesystem for a file's attributes. The caller must indicate in |
| 183 | * request_mask and query_flags to indicate what they want. |
| 184 | * |
| 185 | * If the file is remote, the filesystem can be forced to update the attributes |
| 186 | * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can |
| 187 | * suppress the update by passing AT_STATX_DONT_SYNC. |
| 188 | * |
| 189 | * Bits must have been set in request_mask to indicate which attributes the |
| 190 | * caller wants retrieving. Any such attribute not requested may be returned |
| 191 | * anyway, but the value may be approximate, and, if remote, may not have been |
| 192 | * synchronised with the server. |
| 193 | * |
| 194 | * 0 will be returned on success, and a -ve error code if unsuccessful. |
| 195 | */ |
| 196 | int vfs_getattr(const struct path *path, struct kstat *stat, |
| 197 | u32 request_mask, unsigned int query_flags) |
| 198 | { |
| 199 | int retval; |
| 200 | |
| 201 | if (WARN_ON_ONCE(query_flags & AT_GETATTR_NOSEC)) |
| 202 | return -EPERM; |
| 203 | |
| 204 | retval = security_inode_getattr(path); |
| 205 | if (retval) |
| 206 | return retval; |
| 207 | return vfs_getattr_nosec(path, stat, request_mask, query_flags); |
| 208 | } |
| 209 | EXPORT_SYMBOL(vfs_getattr); |
| 210 | |
| 211 | /** |
| 212 | * vfs_fstat - Get the basic attributes by file descriptor |
| 213 | * @fd: The file descriptor referring to the file of interest |
| 214 | * @stat: The result structure to fill in. |
| 215 | * |
| 216 | * This function is a wrapper around vfs_getattr(). The main difference is |
| 217 | * that it uses a file descriptor to determine the file location. |
| 218 | * |
| 219 | * 0 will be returned on success, and a -ve error code if unsuccessful. |
| 220 | */ |
| 221 | int vfs_fstat(int fd, struct kstat *stat) |
| 222 | { |
| 223 | struct fd f; |
| 224 | int error; |
| 225 | |
| 226 | f = fdget_raw(fd); |
| 227 | if (!fd_file(f)) |
| 228 | return -EBADF; |
| 229 | error = vfs_getattr(&fd_file(f)->f_path, stat, STATX_BASIC_STATS, 0); |
| 230 | fdput(f); |
| 231 | return error; |
| 232 | } |
| 233 | |
| 234 | int getname_statx_lookup_flags(int flags) |
| 235 | { |
| 236 | int lookup_flags = 0; |
| 237 | |
| 238 | if (!(flags & AT_SYMLINK_NOFOLLOW)) |
| 239 | lookup_flags |= LOOKUP_FOLLOW; |
| 240 | if (!(flags & AT_NO_AUTOMOUNT)) |
| 241 | lookup_flags |= LOOKUP_AUTOMOUNT; |
| 242 | if (flags & AT_EMPTY_PATH) |
| 243 | lookup_flags |= LOOKUP_EMPTY; |
| 244 | |
| 245 | return lookup_flags; |
| 246 | } |
| 247 | |
| 248 | static int vfs_statx_path(struct path *path, int flags, struct kstat *stat, |
| 249 | u32 request_mask) |
| 250 | { |
| 251 | int error = vfs_getattr(path, stat, request_mask, flags); |
| 252 | |
| 253 | if (request_mask & STATX_MNT_ID_UNIQUE) { |
| 254 | stat->mnt_id = real_mount(path->mnt)->mnt_id_unique; |
| 255 | stat->result_mask |= STATX_MNT_ID_UNIQUE; |
| 256 | } else { |
| 257 | stat->mnt_id = real_mount(path->mnt)->mnt_id; |
| 258 | stat->result_mask |= STATX_MNT_ID; |
| 259 | } |
| 260 | |
| 261 | if (path_mounted(path)) |
| 262 | stat->attributes |= STATX_ATTR_MOUNT_ROOT; |
| 263 | stat->attributes_mask |= STATX_ATTR_MOUNT_ROOT; |
| 264 | |
| 265 | /* |
| 266 | * If this is a block device inode, override the filesystem |
| 267 | * attributes with the block device specific parameters that need to be |
| 268 | * obtained from the bdev backing inode. |
| 269 | */ |
| 270 | if (S_ISBLK(stat->mode)) |
| 271 | bdev_statx(path, stat, request_mask); |
| 272 | |
| 273 | return error; |
| 274 | } |
| 275 | |
| 276 | static int vfs_statx_fd(int fd, int flags, struct kstat *stat, |
| 277 | u32 request_mask) |
| 278 | { |
| 279 | CLASS(fd_raw, f)(fd); |
| 280 | if (!fd_file(f)) |
| 281 | return -EBADF; |
| 282 | return vfs_statx_path(&fd_file(f)->f_path, flags, stat, request_mask); |
| 283 | } |
| 284 | |
| 285 | /** |
| 286 | * vfs_statx - Get basic and extra attributes by filename |
| 287 | * @dfd: A file descriptor representing the base dir for a relative filename |
| 288 | * @filename: The name of the file of interest |
| 289 | * @flags: Flags to control the query |
| 290 | * @stat: The result structure to fill in. |
| 291 | * @request_mask: STATX_xxx flags indicating what the caller wants |
| 292 | * |
| 293 | * This function is a wrapper around vfs_getattr(). The main difference is |
| 294 | * that it uses a filename and base directory to determine the file location. |
| 295 | * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink |
| 296 | * at the given name from being referenced. |
| 297 | * |
| 298 | * 0 will be returned on success, and a -ve error code if unsuccessful. |
| 299 | */ |
| 300 | static int vfs_statx(int dfd, struct filename *filename, int flags, |
| 301 | struct kstat *stat, u32 request_mask) |
| 302 | { |
| 303 | struct path path; |
| 304 | unsigned int lookup_flags = getname_statx_lookup_flags(flags); |
| 305 | int error; |
| 306 | |
| 307 | if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | AT_EMPTY_PATH | |
| 308 | AT_STATX_SYNC_TYPE)) |
| 309 | return -EINVAL; |
| 310 | |
| 311 | retry: |
| 312 | error = filename_lookup(dfd, filename, lookup_flags, &path, NULL); |
| 313 | if (error) |
| 314 | return error; |
| 315 | error = vfs_statx_path(&path, flags, stat, request_mask); |
| 316 | path_put(&path); |
| 317 | if (retry_estale(error, lookup_flags)) { |
| 318 | lookup_flags |= LOOKUP_REVAL; |
| 319 | goto retry; |
| 320 | } |
| 321 | return error; |
| 322 | } |
| 323 | |
| 324 | int vfs_fstatat(int dfd, const char __user *filename, |
| 325 | struct kstat *stat, int flags) |
| 326 | { |
| 327 | int ret; |
| 328 | int statx_flags = flags | AT_NO_AUTOMOUNT; |
| 329 | struct filename *name; |
| 330 | |
| 331 | /* |
| 332 | * Work around glibc turning fstat() into fstatat(AT_EMPTY_PATH) |
| 333 | * |
| 334 | * If AT_EMPTY_PATH is set, we expect the common case to be that |
| 335 | * empty path, and avoid doing all the extra pathname work. |
| 336 | */ |
| 337 | if (flags == AT_EMPTY_PATH && vfs_empty_path(dfd, filename)) |
| 338 | return vfs_fstat(dfd, stat); |
| 339 | |
| 340 | name = getname_flags(filename, getname_statx_lookup_flags(statx_flags)); |
| 341 | ret = vfs_statx(dfd, name, statx_flags, stat, STATX_BASIC_STATS); |
| 342 | putname(name); |
| 343 | |
| 344 | return ret; |
| 345 | } |
| 346 | |
| 347 | #ifdef __ARCH_WANT_OLD_STAT |
| 348 | |
| 349 | /* |
| 350 | * For backward compatibility? Maybe this should be moved |
| 351 | * into arch/i386 instead? |
| 352 | */ |
| 353 | static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) |
| 354 | { |
| 355 | static int warncount = 5; |
| 356 | struct __old_kernel_stat tmp; |
| 357 | |
| 358 | if (warncount > 0) { |
| 359 | warncount--; |
| 360 | printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", |
| 361 | current->comm); |
| 362 | } else if (warncount < 0) { |
| 363 | /* it's laughable, but... */ |
| 364 | warncount = 0; |
| 365 | } |
| 366 | |
| 367 | memset(&tmp, 0, sizeof(struct __old_kernel_stat)); |
| 368 | tmp.st_dev = old_encode_dev(stat->dev); |
| 369 | tmp.st_ino = stat->ino; |
| 370 | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) |
| 371 | return -EOVERFLOW; |
| 372 | tmp.st_mode = stat->mode; |
| 373 | tmp.st_nlink = stat->nlink; |
| 374 | if (tmp.st_nlink != stat->nlink) |
| 375 | return -EOVERFLOW; |
| 376 | SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); |
| 377 | SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); |
| 378 | tmp.st_rdev = old_encode_dev(stat->rdev); |
| 379 | #if BITS_PER_LONG == 32 |
| 380 | if (stat->size > MAX_NON_LFS) |
| 381 | return -EOVERFLOW; |
| 382 | #endif |
| 383 | tmp.st_size = stat->size; |
| 384 | tmp.st_atime = stat->atime.tv_sec; |
| 385 | tmp.st_mtime = stat->mtime.tv_sec; |
| 386 | tmp.st_ctime = stat->ctime.tv_sec; |
| 387 | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; |
| 388 | } |
| 389 | |
| 390 | SYSCALL_DEFINE2(stat, const char __user *, filename, |
| 391 | struct __old_kernel_stat __user *, statbuf) |
| 392 | { |
| 393 | struct kstat stat; |
| 394 | int error; |
| 395 | |
| 396 | error = vfs_stat(filename, &stat); |
| 397 | if (error) |
| 398 | return error; |
| 399 | |
| 400 | return cp_old_stat(&stat, statbuf); |
| 401 | } |
| 402 | |
| 403 | SYSCALL_DEFINE2(lstat, const char __user *, filename, |
| 404 | struct __old_kernel_stat __user *, statbuf) |
| 405 | { |
| 406 | struct kstat stat; |
| 407 | int error; |
| 408 | |
| 409 | error = vfs_lstat(filename, &stat); |
| 410 | if (error) |
| 411 | return error; |
| 412 | |
| 413 | return cp_old_stat(&stat, statbuf); |
| 414 | } |
| 415 | |
| 416 | SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf) |
| 417 | { |
| 418 | struct kstat stat; |
| 419 | int error = vfs_fstat(fd, &stat); |
| 420 | |
| 421 | if (!error) |
| 422 | error = cp_old_stat(&stat, statbuf); |
| 423 | |
| 424 | return error; |
| 425 | } |
| 426 | |
| 427 | #endif /* __ARCH_WANT_OLD_STAT */ |
| 428 | |
| 429 | #ifdef __ARCH_WANT_NEW_STAT |
| 430 | |
| 431 | #ifndef INIT_STRUCT_STAT_PADDING |
| 432 | # define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st)) |
| 433 | #endif |
| 434 | |
| 435 | static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) |
| 436 | { |
| 437 | struct stat tmp; |
| 438 | |
| 439 | if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev)) |
| 440 | return -EOVERFLOW; |
| 441 | if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev)) |
| 442 | return -EOVERFLOW; |
| 443 | #if BITS_PER_LONG == 32 |
| 444 | if (stat->size > MAX_NON_LFS) |
| 445 | return -EOVERFLOW; |
| 446 | #endif |
| 447 | |
| 448 | INIT_STRUCT_STAT_PADDING(tmp); |
| 449 | tmp.st_dev = new_encode_dev(stat->dev); |
| 450 | tmp.st_ino = stat->ino; |
| 451 | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) |
| 452 | return -EOVERFLOW; |
| 453 | tmp.st_mode = stat->mode; |
| 454 | tmp.st_nlink = stat->nlink; |
| 455 | if (tmp.st_nlink != stat->nlink) |
| 456 | return -EOVERFLOW; |
| 457 | SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); |
| 458 | SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); |
| 459 | tmp.st_rdev = new_encode_dev(stat->rdev); |
| 460 | tmp.st_size = stat->size; |
| 461 | tmp.st_atime = stat->atime.tv_sec; |
| 462 | tmp.st_mtime = stat->mtime.tv_sec; |
| 463 | tmp.st_ctime = stat->ctime.tv_sec; |
| 464 | #ifdef STAT_HAVE_NSEC |
| 465 | tmp.st_atime_nsec = stat->atime.tv_nsec; |
| 466 | tmp.st_mtime_nsec = stat->mtime.tv_nsec; |
| 467 | tmp.st_ctime_nsec = stat->ctime.tv_nsec; |
| 468 | #endif |
| 469 | tmp.st_blocks = stat->blocks; |
| 470 | tmp.st_blksize = stat->blksize; |
| 471 | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; |
| 472 | } |
| 473 | |
| 474 | SYSCALL_DEFINE2(newstat, const char __user *, filename, |
| 475 | struct stat __user *, statbuf) |
| 476 | { |
| 477 | struct kstat stat; |
| 478 | int error = vfs_stat(filename, &stat); |
| 479 | |
| 480 | if (error) |
| 481 | return error; |
| 482 | return cp_new_stat(&stat, statbuf); |
| 483 | } |
| 484 | |
| 485 | SYSCALL_DEFINE2(newlstat, const char __user *, filename, |
| 486 | struct stat __user *, statbuf) |
| 487 | { |
| 488 | struct kstat stat; |
| 489 | int error; |
| 490 | |
| 491 | error = vfs_lstat(filename, &stat); |
| 492 | if (error) |
| 493 | return error; |
| 494 | |
| 495 | return cp_new_stat(&stat, statbuf); |
| 496 | } |
| 497 | |
| 498 | #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) |
| 499 | SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename, |
| 500 | struct stat __user *, statbuf, int, flag) |
| 501 | { |
| 502 | struct kstat stat; |
| 503 | int error; |
| 504 | |
| 505 | error = vfs_fstatat(dfd, filename, &stat, flag); |
| 506 | if (error) |
| 507 | return error; |
| 508 | return cp_new_stat(&stat, statbuf); |
| 509 | } |
| 510 | #endif |
| 511 | |
| 512 | SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf) |
| 513 | { |
| 514 | struct kstat stat; |
| 515 | int error = vfs_fstat(fd, &stat); |
| 516 | |
| 517 | if (!error) |
| 518 | error = cp_new_stat(&stat, statbuf); |
| 519 | |
| 520 | return error; |
| 521 | } |
| 522 | #endif |
| 523 | |
| 524 | static int do_readlinkat(int dfd, const char __user *pathname, |
| 525 | char __user *buf, int bufsiz) |
| 526 | { |
| 527 | struct path path; |
| 528 | struct filename *name; |
| 529 | int error; |
| 530 | unsigned int lookup_flags = LOOKUP_EMPTY; |
| 531 | |
| 532 | if (bufsiz <= 0) |
| 533 | return -EINVAL; |
| 534 | |
| 535 | retry: |
| 536 | name = getname_flags(pathname, lookup_flags); |
| 537 | error = filename_lookup(dfd, name, lookup_flags, &path, NULL); |
| 538 | if (unlikely(error)) { |
| 539 | putname(name); |
| 540 | return error; |
| 541 | } |
| 542 | |
| 543 | /* |
| 544 | * AFS mountpoints allow readlink(2) but are not symlinks |
| 545 | */ |
| 546 | if (d_is_symlink(path.dentry) || |
| 547 | d_backing_inode(path.dentry)->i_op->readlink) { |
| 548 | error = security_inode_readlink(path.dentry); |
| 549 | if (!error) { |
| 550 | touch_atime(&path); |
| 551 | error = vfs_readlink(path.dentry, buf, bufsiz); |
| 552 | } |
| 553 | } else { |
| 554 | error = (name->name[0] == '\0') ? -ENOENT : -EINVAL; |
| 555 | } |
| 556 | path_put(&path); |
| 557 | putname(name); |
| 558 | if (retry_estale(error, lookup_flags)) { |
| 559 | lookup_flags |= LOOKUP_REVAL; |
| 560 | goto retry; |
| 561 | } |
| 562 | return error; |
| 563 | } |
| 564 | |
| 565 | SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, |
| 566 | char __user *, buf, int, bufsiz) |
| 567 | { |
| 568 | return do_readlinkat(dfd, pathname, buf, bufsiz); |
| 569 | } |
| 570 | |
| 571 | SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf, |
| 572 | int, bufsiz) |
| 573 | { |
| 574 | return do_readlinkat(AT_FDCWD, path, buf, bufsiz); |
| 575 | } |
| 576 | |
| 577 | |
| 578 | /* ---------- LFS-64 ----------- */ |
| 579 | #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64) |
| 580 | |
| 581 | #ifndef INIT_STRUCT_STAT64_PADDING |
| 582 | # define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st)) |
| 583 | #endif |
| 584 | |
| 585 | static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) |
| 586 | { |
| 587 | struct stat64 tmp; |
| 588 | |
| 589 | INIT_STRUCT_STAT64_PADDING(tmp); |
| 590 | #ifdef CONFIG_MIPS |
| 591 | /* mips has weird padding, so we don't get 64 bits there */ |
| 592 | tmp.st_dev = new_encode_dev(stat->dev); |
| 593 | tmp.st_rdev = new_encode_dev(stat->rdev); |
| 594 | #else |
| 595 | tmp.st_dev = huge_encode_dev(stat->dev); |
| 596 | tmp.st_rdev = huge_encode_dev(stat->rdev); |
| 597 | #endif |
| 598 | tmp.st_ino = stat->ino; |
| 599 | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) |
| 600 | return -EOVERFLOW; |
| 601 | #ifdef STAT64_HAS_BROKEN_ST_INO |
| 602 | tmp.__st_ino = stat->ino; |
| 603 | #endif |
| 604 | tmp.st_mode = stat->mode; |
| 605 | tmp.st_nlink = stat->nlink; |
| 606 | tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid); |
| 607 | tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid); |
| 608 | tmp.st_atime = stat->atime.tv_sec; |
| 609 | tmp.st_atime_nsec = stat->atime.tv_nsec; |
| 610 | tmp.st_mtime = stat->mtime.tv_sec; |
| 611 | tmp.st_mtime_nsec = stat->mtime.tv_nsec; |
| 612 | tmp.st_ctime = stat->ctime.tv_sec; |
| 613 | tmp.st_ctime_nsec = stat->ctime.tv_nsec; |
| 614 | tmp.st_size = stat->size; |
| 615 | tmp.st_blocks = stat->blocks; |
| 616 | tmp.st_blksize = stat->blksize; |
| 617 | return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; |
| 618 | } |
| 619 | |
| 620 | SYSCALL_DEFINE2(stat64, const char __user *, filename, |
| 621 | struct stat64 __user *, statbuf) |
| 622 | { |
| 623 | struct kstat stat; |
| 624 | int error = vfs_stat(filename, &stat); |
| 625 | |
| 626 | if (!error) |
| 627 | error = cp_new_stat64(&stat, statbuf); |
| 628 | |
| 629 | return error; |
| 630 | } |
| 631 | |
| 632 | SYSCALL_DEFINE2(lstat64, const char __user *, filename, |
| 633 | struct stat64 __user *, statbuf) |
| 634 | { |
| 635 | struct kstat stat; |
| 636 | int error = vfs_lstat(filename, &stat); |
| 637 | |
| 638 | if (!error) |
| 639 | error = cp_new_stat64(&stat, statbuf); |
| 640 | |
| 641 | return error; |
| 642 | } |
| 643 | |
| 644 | SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf) |
| 645 | { |
| 646 | struct kstat stat; |
| 647 | int error = vfs_fstat(fd, &stat); |
| 648 | |
| 649 | if (!error) |
| 650 | error = cp_new_stat64(&stat, statbuf); |
| 651 | |
| 652 | return error; |
| 653 | } |
| 654 | |
| 655 | SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename, |
| 656 | struct stat64 __user *, statbuf, int, flag) |
| 657 | { |
| 658 | struct kstat stat; |
| 659 | int error; |
| 660 | |
| 661 | error = vfs_fstatat(dfd, filename, &stat, flag); |
| 662 | if (error) |
| 663 | return error; |
| 664 | return cp_new_stat64(&stat, statbuf); |
| 665 | } |
| 666 | #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */ |
| 667 | |
| 668 | static noinline_for_stack int |
| 669 | cp_statx(const struct kstat *stat, struct statx __user *buffer) |
| 670 | { |
| 671 | struct statx tmp; |
| 672 | |
| 673 | memset(&tmp, 0, sizeof(tmp)); |
| 674 | |
| 675 | /* STATX_CHANGE_COOKIE is kernel-only for now */ |
| 676 | tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE; |
| 677 | tmp.stx_blksize = stat->blksize; |
| 678 | /* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */ |
| 679 | tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC; |
| 680 | tmp.stx_nlink = stat->nlink; |
| 681 | tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid); |
| 682 | tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid); |
| 683 | tmp.stx_mode = stat->mode; |
| 684 | tmp.stx_ino = stat->ino; |
| 685 | tmp.stx_size = stat->size; |
| 686 | tmp.stx_blocks = stat->blocks; |
| 687 | tmp.stx_attributes_mask = stat->attributes_mask; |
| 688 | tmp.stx_atime.tv_sec = stat->atime.tv_sec; |
| 689 | tmp.stx_atime.tv_nsec = stat->atime.tv_nsec; |
| 690 | tmp.stx_btime.tv_sec = stat->btime.tv_sec; |
| 691 | tmp.stx_btime.tv_nsec = stat->btime.tv_nsec; |
| 692 | tmp.stx_ctime.tv_sec = stat->ctime.tv_sec; |
| 693 | tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec; |
| 694 | tmp.stx_mtime.tv_sec = stat->mtime.tv_sec; |
| 695 | tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec; |
| 696 | tmp.stx_rdev_major = MAJOR(stat->rdev); |
| 697 | tmp.stx_rdev_minor = MINOR(stat->rdev); |
| 698 | tmp.stx_dev_major = MAJOR(stat->dev); |
| 699 | tmp.stx_dev_minor = MINOR(stat->dev); |
| 700 | tmp.stx_mnt_id = stat->mnt_id; |
| 701 | tmp.stx_dio_mem_align = stat->dio_mem_align; |
| 702 | tmp.stx_dio_offset_align = stat->dio_offset_align; |
| 703 | tmp.stx_subvol = stat->subvol; |
| 704 | tmp.stx_atomic_write_unit_min = stat->atomic_write_unit_min; |
| 705 | tmp.stx_atomic_write_unit_max = stat->atomic_write_unit_max; |
| 706 | tmp.stx_atomic_write_segments_max = stat->atomic_write_segments_max; |
| 707 | |
| 708 | return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0; |
| 709 | } |
| 710 | |
| 711 | int do_statx(int dfd, struct filename *filename, unsigned int flags, |
| 712 | unsigned int mask, struct statx __user *buffer) |
| 713 | { |
| 714 | struct kstat stat; |
| 715 | int error; |
| 716 | |
| 717 | if (mask & STATX__RESERVED) |
| 718 | return -EINVAL; |
| 719 | if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE) |
| 720 | return -EINVAL; |
| 721 | |
| 722 | /* |
| 723 | * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests |
| 724 | * from userland. |
| 725 | */ |
| 726 | mask &= ~STATX_CHANGE_COOKIE; |
| 727 | |
| 728 | error = vfs_statx(dfd, filename, flags, &stat, mask); |
| 729 | if (error) |
| 730 | return error; |
| 731 | |
| 732 | return cp_statx(&stat, buffer); |
| 733 | } |
| 734 | |
| 735 | int do_statx_fd(int fd, unsigned int flags, unsigned int mask, |
| 736 | struct statx __user *buffer) |
| 737 | { |
| 738 | struct kstat stat; |
| 739 | int error; |
| 740 | |
| 741 | if (mask & STATX__RESERVED) |
| 742 | return -EINVAL; |
| 743 | if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE) |
| 744 | return -EINVAL; |
| 745 | |
| 746 | /* |
| 747 | * STATX_CHANGE_COOKIE is kernel-only for now. Ignore requests |
| 748 | * from userland. |
| 749 | */ |
| 750 | mask &= ~STATX_CHANGE_COOKIE; |
| 751 | |
| 752 | error = vfs_statx_fd(fd, flags, &stat, mask); |
| 753 | if (error) |
| 754 | return error; |
| 755 | |
| 756 | return cp_statx(&stat, buffer); |
| 757 | } |
| 758 | |
| 759 | /** |
| 760 | * sys_statx - System call to get enhanced stats |
| 761 | * @dfd: Base directory to pathwalk from *or* fd to stat. |
| 762 | * @filename: File to stat or either NULL or "" with AT_EMPTY_PATH |
| 763 | * @flags: AT_* flags to control pathwalk. |
| 764 | * @mask: Parts of statx struct actually required. |
| 765 | * @buffer: Result buffer. |
| 766 | * |
| 767 | * Note that fstat() can be emulated by setting dfd to the fd of interest, |
| 768 | * supplying "" (or preferably NULL) as the filename and setting AT_EMPTY_PATH |
| 769 | * in the flags. |
| 770 | */ |
| 771 | SYSCALL_DEFINE5(statx, |
| 772 | int, dfd, const char __user *, filename, unsigned, flags, |
| 773 | unsigned int, mask, |
| 774 | struct statx __user *, buffer) |
| 775 | { |
| 776 | int ret; |
| 777 | unsigned lflags; |
| 778 | struct filename *name; |
| 779 | |
| 780 | /* |
| 781 | * Short-circuit handling of NULL and "" paths. |
| 782 | * |
| 783 | * For a NULL path we require and accept only the AT_EMPTY_PATH flag |
| 784 | * (possibly |'d with AT_STATX flags). |
| 785 | * |
| 786 | * However, glibc on 32-bit architectures implements fstatat as statx |
| 787 | * with the "" pathname and AT_NO_AUTOMOUNT | AT_EMPTY_PATH flags. |
| 788 | * Supporting this results in the uglification below. |
| 789 | */ |
| 790 | lflags = flags & ~(AT_NO_AUTOMOUNT | AT_STATX_SYNC_TYPE); |
| 791 | if (lflags == AT_EMPTY_PATH && vfs_empty_path(dfd, filename)) |
| 792 | return do_statx_fd(dfd, flags & ~AT_NO_AUTOMOUNT, mask, buffer); |
| 793 | |
| 794 | name = getname_flags(filename, getname_statx_lookup_flags(flags)); |
| 795 | ret = do_statx(dfd, name, flags, mask, buffer); |
| 796 | putname(name); |
| 797 | |
| 798 | return ret; |
| 799 | } |
| 800 | |
| 801 | #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_STAT) |
| 802 | static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf) |
| 803 | { |
| 804 | struct compat_stat tmp; |
| 805 | |
| 806 | if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev)) |
| 807 | return -EOVERFLOW; |
| 808 | if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev)) |
| 809 | return -EOVERFLOW; |
| 810 | |
| 811 | memset(&tmp, 0, sizeof(tmp)); |
| 812 | tmp.st_dev = new_encode_dev(stat->dev); |
| 813 | tmp.st_ino = stat->ino; |
| 814 | if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) |
| 815 | return -EOVERFLOW; |
| 816 | tmp.st_mode = stat->mode; |
| 817 | tmp.st_nlink = stat->nlink; |
| 818 | if (tmp.st_nlink != stat->nlink) |
| 819 | return -EOVERFLOW; |
| 820 | SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); |
| 821 | SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); |
| 822 | tmp.st_rdev = new_encode_dev(stat->rdev); |
| 823 | if ((u64) stat->size > MAX_NON_LFS) |
| 824 | return -EOVERFLOW; |
| 825 | tmp.st_size = stat->size; |
| 826 | tmp.st_atime = stat->atime.tv_sec; |
| 827 | tmp.st_atime_nsec = stat->atime.tv_nsec; |
| 828 | tmp.st_mtime = stat->mtime.tv_sec; |
| 829 | tmp.st_mtime_nsec = stat->mtime.tv_nsec; |
| 830 | tmp.st_ctime = stat->ctime.tv_sec; |
| 831 | tmp.st_ctime_nsec = stat->ctime.tv_nsec; |
| 832 | tmp.st_blocks = stat->blocks; |
| 833 | tmp.st_blksize = stat->blksize; |
| 834 | return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0; |
| 835 | } |
| 836 | |
| 837 | COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename, |
| 838 | struct compat_stat __user *, statbuf) |
| 839 | { |
| 840 | struct kstat stat; |
| 841 | int error; |
| 842 | |
| 843 | error = vfs_stat(filename, &stat); |
| 844 | if (error) |
| 845 | return error; |
| 846 | return cp_compat_stat(&stat, statbuf); |
| 847 | } |
| 848 | |
| 849 | COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename, |
| 850 | struct compat_stat __user *, statbuf) |
| 851 | { |
| 852 | struct kstat stat; |
| 853 | int error; |
| 854 | |
| 855 | error = vfs_lstat(filename, &stat); |
| 856 | if (error) |
| 857 | return error; |
| 858 | return cp_compat_stat(&stat, statbuf); |
| 859 | } |
| 860 | |
| 861 | #ifndef __ARCH_WANT_STAT64 |
| 862 | COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd, |
| 863 | const char __user *, filename, |
| 864 | struct compat_stat __user *, statbuf, int, flag) |
| 865 | { |
| 866 | struct kstat stat; |
| 867 | int error; |
| 868 | |
| 869 | error = vfs_fstatat(dfd, filename, &stat, flag); |
| 870 | if (error) |
| 871 | return error; |
| 872 | return cp_compat_stat(&stat, statbuf); |
| 873 | } |
| 874 | #endif |
| 875 | |
| 876 | COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd, |
| 877 | struct compat_stat __user *, statbuf) |
| 878 | { |
| 879 | struct kstat stat; |
| 880 | int error = vfs_fstat(fd, &stat); |
| 881 | |
| 882 | if (!error) |
| 883 | error = cp_compat_stat(&stat, statbuf); |
| 884 | return error; |
| 885 | } |
| 886 | #endif |
| 887 | |
| 888 | /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */ |
| 889 | void __inode_add_bytes(struct inode *inode, loff_t bytes) |
| 890 | { |
| 891 | inode->i_blocks += bytes >> 9; |
| 892 | bytes &= 511; |
| 893 | inode->i_bytes += bytes; |
| 894 | if (inode->i_bytes >= 512) { |
| 895 | inode->i_blocks++; |
| 896 | inode->i_bytes -= 512; |
| 897 | } |
| 898 | } |
| 899 | EXPORT_SYMBOL(__inode_add_bytes); |
| 900 | |
| 901 | void inode_add_bytes(struct inode *inode, loff_t bytes) |
| 902 | { |
| 903 | spin_lock(&inode->i_lock); |
| 904 | __inode_add_bytes(inode, bytes); |
| 905 | spin_unlock(&inode->i_lock); |
| 906 | } |
| 907 | |
| 908 | EXPORT_SYMBOL(inode_add_bytes); |
| 909 | |
| 910 | void __inode_sub_bytes(struct inode *inode, loff_t bytes) |
| 911 | { |
| 912 | inode->i_blocks -= bytes >> 9; |
| 913 | bytes &= 511; |
| 914 | if (inode->i_bytes < bytes) { |
| 915 | inode->i_blocks--; |
| 916 | inode->i_bytes += 512; |
| 917 | } |
| 918 | inode->i_bytes -= bytes; |
| 919 | } |
| 920 | |
| 921 | EXPORT_SYMBOL(__inode_sub_bytes); |
| 922 | |
| 923 | void inode_sub_bytes(struct inode *inode, loff_t bytes) |
| 924 | { |
| 925 | spin_lock(&inode->i_lock); |
| 926 | __inode_sub_bytes(inode, bytes); |
| 927 | spin_unlock(&inode->i_lock); |
| 928 | } |
| 929 | |
| 930 | EXPORT_SYMBOL(inode_sub_bytes); |
| 931 | |
| 932 | loff_t inode_get_bytes(struct inode *inode) |
| 933 | { |
| 934 | loff_t ret; |
| 935 | |
| 936 | spin_lock(&inode->i_lock); |
| 937 | ret = __inode_get_bytes(inode); |
| 938 | spin_unlock(&inode->i_lock); |
| 939 | return ret; |
| 940 | } |
| 941 | |
| 942 | EXPORT_SYMBOL(inode_get_bytes); |
| 943 | |
| 944 | void inode_set_bytes(struct inode *inode, loff_t bytes) |
| 945 | { |
| 946 | /* Caller is here responsible for sufficient locking |
| 947 | * (ie. inode->i_lock) */ |
| 948 | inode->i_blocks = bytes >> 9; |
| 949 | inode->i_bytes = bytes & 511; |
| 950 | } |
| 951 | |
| 952 | EXPORT_SYMBOL(inode_set_bytes); |