1 /* 2 * linux/fs/stat.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include <linux/export.h> 8 #include <linux/mm.h> 9 #include <linux/errno.h> 10 #include <linux/file.h> 11 #include <linux/highuid.h> 12 #include <linux/fs.h> 13 #include <linux/namei.h> 14 #include <linux/security.h> 15 #include <linux/syscalls.h> 16 #include <linux/pagemap.h> 17 18 #include <linux/uaccess.h> 19 #include <asm/unistd.h> 20 21 void generic_fillattr(struct inode *inode, struct kstat *stat) 22 { 23 stat->dev = inode->i_sb->s_dev; 24 stat->ino = inode->i_ino; 25 stat->mode = inode->i_mode; 26 stat->nlink = inode->i_nlink; 27 stat->uid = inode->i_uid; 28 stat->gid = inode->i_gid; 29 stat->rdev = inode->i_rdev; 30 stat->size = i_size_read(inode); 31 stat->atime = inode->i_atime; 32 stat->mtime = inode->i_mtime; 33 stat->ctime = inode->i_ctime; 34 stat->blksize = (1 << inode->i_blkbits); 35 stat->blocks = inode->i_blocks; 36 } 37 38 EXPORT_SYMBOL(generic_fillattr); 39 40 /** 41 * vfs_getattr_nosec - getattr without security checks 42 * @path: file to get attributes from 43 * @stat: structure to return attributes in 44 * 45 * Get attributes without calling security_inode_getattr. 46 * 47 * Currently the only caller other than vfs_getattr is internal to the 48 * filehandle lookup code, which uses only the inode number and returns 49 * no attributes to any user. Any other code probably wants 50 * vfs_getattr. 51 */ 52 int vfs_getattr_nosec(struct path *path, struct kstat *stat) 53 { 54 struct inode *inode = d_backing_inode(path->dentry); 55 56 if (inode->i_op->getattr) 57 return inode->i_op->getattr(path->mnt, path->dentry, stat); 58 59 generic_fillattr(inode, stat); 60 return 0; 61 } 62 63 EXPORT_SYMBOL(vfs_getattr_nosec); 64 65 int vfs_getattr(struct path *path, struct kstat *stat) 66 { 67 int retval; 68 69 retval = security_inode_getattr(path); 70 if (retval) 71 return retval; 72 return vfs_getattr_nosec(path, stat); 73 } 74 75 EXPORT_SYMBOL(vfs_getattr); 76 77 int vfs_fstat(unsigned int fd, struct kstat *stat) 78 { 79 struct fd f = fdget_raw(fd); 80 int error = -EBADF; 81 82 if (f.file) { 83 error = vfs_getattr(&f.file->f_path, stat); 84 fdput(f); 85 } 86 return error; 87 } 88 EXPORT_SYMBOL(vfs_fstat); 89 90 int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat, 91 int flag) 92 { 93 struct path path; 94 int error = -EINVAL; 95 unsigned int lookup_flags = 0; 96 97 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | 98 AT_EMPTY_PATH)) != 0) 99 goto out; 100 101 if (!(flag & AT_SYMLINK_NOFOLLOW)) 102 lookup_flags |= LOOKUP_FOLLOW; 103 if (flag & AT_EMPTY_PATH) 104 lookup_flags |= LOOKUP_EMPTY; 105 retry: 106 error = user_path_at(dfd, filename, lookup_flags, &path); 107 if (error) 108 goto out; 109 110 error = vfs_getattr(&path, stat); 111 path_put(&path); 112 if (retry_estale(error, lookup_flags)) { 113 lookup_flags |= LOOKUP_REVAL; 114 goto retry; 115 } 116 out: 117 return error; 118 } 119 EXPORT_SYMBOL(vfs_fstatat); 120 121 int vfs_stat(const char __user *name, struct kstat *stat) 122 { 123 return vfs_fstatat(AT_FDCWD, name, stat, 0); 124 } 125 EXPORT_SYMBOL(vfs_stat); 126 127 int vfs_lstat(const char __user *name, struct kstat *stat) 128 { 129 return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW); 130 } 131 EXPORT_SYMBOL(vfs_lstat); 132 133 134 #ifdef __ARCH_WANT_OLD_STAT 135 136 /* 137 * For backward compatibility? Maybe this should be moved 138 * into arch/i386 instead? 139 */ 140 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 141 { 142 static int warncount = 5; 143 struct __old_kernel_stat tmp; 144 145 if (warncount > 0) { 146 warncount--; 147 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 148 current->comm); 149 } else if (warncount < 0) { 150 /* it's laughable, but... */ 151 warncount = 0; 152 } 153 154 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 155 tmp.st_dev = old_encode_dev(stat->dev); 156 tmp.st_ino = stat->ino; 157 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 158 return -EOVERFLOW; 159 tmp.st_mode = stat->mode; 160 tmp.st_nlink = stat->nlink; 161 if (tmp.st_nlink != stat->nlink) 162 return -EOVERFLOW; 163 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid)); 164 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid)); 165 tmp.st_rdev = old_encode_dev(stat->rdev); 166 #if BITS_PER_LONG == 32 167 if (stat->size > MAX_NON_LFS) 168 return -EOVERFLOW; 169 #endif 170 tmp.st_size = stat->size; 171 tmp.st_atime = stat->atime.tv_sec; 172 tmp.st_mtime = stat->mtime.tv_sec; 173 tmp.st_ctime = stat->ctime.tv_sec; 174 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 175 } 176 177 SYSCALL_DEFINE2(stat, const char __user *, filename, 178 struct __old_kernel_stat __user *, statbuf) 179 { 180 struct kstat stat; 181 int error; 182 183 error = vfs_stat(filename, &stat); 184 if (error) 185 return error; 186 187 return cp_old_stat(&stat, statbuf); 188 } 189 190 SYSCALL_DEFINE2(lstat, const char __user *, filename, 191 struct __old_kernel_stat __user *, statbuf) 192 { 193 struct kstat stat; 194 int error; 195 196 error = vfs_lstat(filename, &stat); 197 if (error) 198 return error; 199 200 return cp_old_stat(&stat, statbuf); 201 } 202 203 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf) 204 { 205 struct kstat stat; 206 int error = vfs_fstat(fd, &stat); 207 208 if (!error) 209 error = cp_old_stat(&stat, statbuf); 210 211 return error; 212 } 213 214 #endif /* __ARCH_WANT_OLD_STAT */ 215 216 #if BITS_PER_LONG == 32 217 # define choose_32_64(a,b) a 218 #else 219 # define choose_32_64(a,b) b 220 #endif 221 222 #define valid_dev(x) choose_32_64(old_valid_dev(x),true) 223 #define encode_dev(x) choose_32_64(old_encode_dev,new_encode_dev)(x) 224 225 #ifndef INIT_STRUCT_STAT_PADDING 226 # define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st)) 227 #endif 228 229 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) 230 { 231 struct stat tmp; 232 233 if (!valid_dev(stat->dev) || !valid_dev(stat->rdev)) 234 return -EOVERFLOW; 235 #if BITS_PER_LONG == 32 236 if (stat->size > MAX_NON_LFS) 237 return -EOVERFLOW; 238 #endif 239 240 INIT_STRUCT_STAT_PADDING(tmp); 241 tmp.st_dev = encode_dev(stat->dev); 242 tmp.st_ino = stat->ino; 243 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 244 return -EOVERFLOW; 245 tmp.st_mode = stat->mode; 246 tmp.st_nlink = stat->nlink; 247 if (tmp.st_nlink != stat->nlink) 248 return -EOVERFLOW; 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 = encode_dev(stat->rdev); 252 tmp.st_size = stat->size; 253 tmp.st_atime = stat->atime.tv_sec; 254 tmp.st_mtime = stat->mtime.tv_sec; 255 tmp.st_ctime = stat->ctime.tv_sec; 256 #ifdef STAT_HAVE_NSEC 257 tmp.st_atime_nsec = stat->atime.tv_nsec; 258 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 259 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 260 #endif 261 tmp.st_blocks = stat->blocks; 262 tmp.st_blksize = stat->blksize; 263 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 264 } 265 266 SYSCALL_DEFINE2(newstat, const char __user *, filename, 267 struct stat __user *, statbuf) 268 { 269 struct kstat stat; 270 int error = vfs_stat(filename, &stat); 271 272 if (error) 273 return error; 274 return cp_new_stat(&stat, statbuf); 275 } 276 277 SYSCALL_DEFINE2(newlstat, const char __user *, filename, 278 struct stat __user *, statbuf) 279 { 280 struct kstat stat; 281 int error; 282 283 error = vfs_lstat(filename, &stat); 284 if (error) 285 return error; 286 287 return cp_new_stat(&stat, statbuf); 288 } 289 290 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) 291 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename, 292 struct stat __user *, statbuf, int, flag) 293 { 294 struct kstat stat; 295 int error; 296 297 error = vfs_fstatat(dfd, filename, &stat, flag); 298 if (error) 299 return error; 300 return cp_new_stat(&stat, statbuf); 301 } 302 #endif 303 304 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf) 305 { 306 struct kstat stat; 307 int error = vfs_fstat(fd, &stat); 308 309 if (!error) 310 error = cp_new_stat(&stat, statbuf); 311 312 return error; 313 } 314 315 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, 316 char __user *, buf, int, bufsiz) 317 { 318 struct path path; 319 int error; 320 int empty = 0; 321 unsigned int lookup_flags = LOOKUP_EMPTY; 322 323 if (bufsiz <= 0) 324 return -EINVAL; 325 326 retry: 327 error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty); 328 if (!error) { 329 struct inode *inode = d_backing_inode(path.dentry); 330 331 error = empty ? -ENOENT : -EINVAL; 332 /* 333 * AFS mountpoints allow readlink(2) but are not symlinks 334 */ 335 if (d_is_symlink(path.dentry) || inode->i_op->readlink) { 336 error = security_inode_readlink(path.dentry); 337 if (!error) { 338 touch_atime(&path); 339 error = vfs_readlink(path.dentry, buf, bufsiz); 340 } 341 } 342 path_put(&path); 343 if (retry_estale(error, lookup_flags)) { 344 lookup_flags |= LOOKUP_REVAL; 345 goto retry; 346 } 347 } 348 return error; 349 } 350 351 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf, 352 int, bufsiz) 353 { 354 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 355 } 356 357 358 /* ---------- LFS-64 ----------- */ 359 #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64) 360 361 #ifndef INIT_STRUCT_STAT64_PADDING 362 # define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st)) 363 #endif 364 365 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 366 { 367 struct stat64 tmp; 368 369 INIT_STRUCT_STAT64_PADDING(tmp); 370 #ifdef CONFIG_MIPS 371 /* mips has weird padding, so we don't get 64 bits there */ 372 tmp.st_dev = new_encode_dev(stat->dev); 373 tmp.st_rdev = new_encode_dev(stat->rdev); 374 #else 375 tmp.st_dev = huge_encode_dev(stat->dev); 376 tmp.st_rdev = huge_encode_dev(stat->rdev); 377 #endif 378 tmp.st_ino = stat->ino; 379 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 380 return -EOVERFLOW; 381 #ifdef STAT64_HAS_BROKEN_ST_INO 382 tmp.__st_ino = stat->ino; 383 #endif 384 tmp.st_mode = stat->mode; 385 tmp.st_nlink = stat->nlink; 386 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid); 387 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid); 388 tmp.st_atime = stat->atime.tv_sec; 389 tmp.st_atime_nsec = stat->atime.tv_nsec; 390 tmp.st_mtime = stat->mtime.tv_sec; 391 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 392 tmp.st_ctime = stat->ctime.tv_sec; 393 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 394 tmp.st_size = stat->size; 395 tmp.st_blocks = stat->blocks; 396 tmp.st_blksize = stat->blksize; 397 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 398 } 399 400 SYSCALL_DEFINE2(stat64, const char __user *, filename, 401 struct stat64 __user *, statbuf) 402 { 403 struct kstat stat; 404 int error = vfs_stat(filename, &stat); 405 406 if (!error) 407 error = cp_new_stat64(&stat, statbuf); 408 409 return error; 410 } 411 412 SYSCALL_DEFINE2(lstat64, const char __user *, filename, 413 struct stat64 __user *, statbuf) 414 { 415 struct kstat stat; 416 int error = vfs_lstat(filename, &stat); 417 418 if (!error) 419 error = cp_new_stat64(&stat, statbuf); 420 421 return error; 422 } 423 424 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf) 425 { 426 struct kstat stat; 427 int error = vfs_fstat(fd, &stat); 428 429 if (!error) 430 error = cp_new_stat64(&stat, statbuf); 431 432 return error; 433 } 434 435 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename, 436 struct stat64 __user *, statbuf, int, flag) 437 { 438 struct kstat stat; 439 int error; 440 441 error = vfs_fstatat(dfd, filename, &stat, flag); 442 if (error) 443 return error; 444 return cp_new_stat64(&stat, statbuf); 445 } 446 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */ 447 448 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */ 449 void __inode_add_bytes(struct inode *inode, loff_t bytes) 450 { 451 inode->i_blocks += bytes >> 9; 452 bytes &= 511; 453 inode->i_bytes += bytes; 454 if (inode->i_bytes >= 512) { 455 inode->i_blocks++; 456 inode->i_bytes -= 512; 457 } 458 } 459 460 void inode_add_bytes(struct inode *inode, loff_t bytes) 461 { 462 spin_lock(&inode->i_lock); 463 __inode_add_bytes(inode, bytes); 464 spin_unlock(&inode->i_lock); 465 } 466 467 EXPORT_SYMBOL(inode_add_bytes); 468 469 void __inode_sub_bytes(struct inode *inode, loff_t bytes) 470 { 471 inode->i_blocks -= bytes >> 9; 472 bytes &= 511; 473 if (inode->i_bytes < bytes) { 474 inode->i_blocks--; 475 inode->i_bytes += 512; 476 } 477 inode->i_bytes -= bytes; 478 } 479 480 EXPORT_SYMBOL(__inode_sub_bytes); 481 482 void inode_sub_bytes(struct inode *inode, loff_t bytes) 483 { 484 spin_lock(&inode->i_lock); 485 __inode_sub_bytes(inode, bytes); 486 spin_unlock(&inode->i_lock); 487 } 488 489 EXPORT_SYMBOL(inode_sub_bytes); 490 491 loff_t inode_get_bytes(struct inode *inode) 492 { 493 loff_t ret; 494 495 spin_lock(&inode->i_lock); 496 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; 497 spin_unlock(&inode->i_lock); 498 return ret; 499 } 500 501 EXPORT_SYMBOL(inode_get_bytes); 502 503 void inode_set_bytes(struct inode *inode, loff_t bytes) 504 { 505 /* Caller is here responsible for sufficient locking 506 * (ie. inode->i_lock) */ 507 inode->i_blocks = bytes >> 9; 508 inode->i_bytes = bytes & 511; 509 } 510 511 EXPORT_SYMBOL(inode_set_bytes); 512