1 /* 2 * linux/fs/stat.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include <linux/module.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 <asm/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 int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 41 { 42 struct inode *inode = dentry->d_inode; 43 int retval; 44 45 retval = security_inode_getattr(mnt, dentry); 46 if (retval) 47 return retval; 48 49 if (inode->i_op->getattr) 50 return inode->i_op->getattr(mnt, dentry, stat); 51 52 generic_fillattr(inode, stat); 53 return 0; 54 } 55 56 EXPORT_SYMBOL(vfs_getattr); 57 58 int vfs_fstat(unsigned int fd, struct kstat *stat) 59 { 60 struct file *f = fget(fd); 61 int error = -EBADF; 62 63 if (f) { 64 error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat); 65 fput(f); 66 } 67 return error; 68 } 69 EXPORT_SYMBOL(vfs_fstat); 70 71 int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat, 72 int flag) 73 { 74 struct path path; 75 int error = -EINVAL; 76 int lookup_flags = 0; 77 78 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT | 79 AT_EMPTY_PATH)) != 0) 80 goto out; 81 82 if (!(flag & AT_SYMLINK_NOFOLLOW)) 83 lookup_flags |= LOOKUP_FOLLOW; 84 if (flag & AT_EMPTY_PATH) 85 lookup_flags |= LOOKUP_EMPTY; 86 87 error = user_path_at(dfd, filename, lookup_flags, &path); 88 if (error) 89 goto out; 90 91 error = vfs_getattr(path.mnt, path.dentry, stat); 92 path_put(&path); 93 out: 94 return error; 95 } 96 EXPORT_SYMBOL(vfs_fstatat); 97 98 int vfs_stat(const char __user *name, struct kstat *stat) 99 { 100 return vfs_fstatat(AT_FDCWD, name, stat, 0); 101 } 102 EXPORT_SYMBOL(vfs_stat); 103 104 int vfs_lstat(const char __user *name, struct kstat *stat) 105 { 106 return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW); 107 } 108 EXPORT_SYMBOL(vfs_lstat); 109 110 111 #ifdef __ARCH_WANT_OLD_STAT 112 113 /* 114 * For backward compatibility? Maybe this should be moved 115 * into arch/i386 instead? 116 */ 117 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 118 { 119 static int warncount = 5; 120 struct __old_kernel_stat tmp; 121 122 if (warncount > 0) { 123 warncount--; 124 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 125 current->comm); 126 } else if (warncount < 0) { 127 /* it's laughable, but... */ 128 warncount = 0; 129 } 130 131 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 132 tmp.st_dev = old_encode_dev(stat->dev); 133 tmp.st_ino = stat->ino; 134 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 135 return -EOVERFLOW; 136 tmp.st_mode = stat->mode; 137 tmp.st_nlink = stat->nlink; 138 if (tmp.st_nlink != stat->nlink) 139 return -EOVERFLOW; 140 SET_UID(tmp.st_uid, stat->uid); 141 SET_GID(tmp.st_gid, stat->gid); 142 tmp.st_rdev = old_encode_dev(stat->rdev); 143 #if BITS_PER_LONG == 32 144 if (stat->size > MAX_NON_LFS) 145 return -EOVERFLOW; 146 #endif 147 tmp.st_size = stat->size; 148 tmp.st_atime = stat->atime.tv_sec; 149 tmp.st_mtime = stat->mtime.tv_sec; 150 tmp.st_ctime = stat->ctime.tv_sec; 151 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 152 } 153 154 SYSCALL_DEFINE2(stat, const char __user *, filename, 155 struct __old_kernel_stat __user *, statbuf) 156 { 157 struct kstat stat; 158 int error; 159 160 error = vfs_stat(filename, &stat); 161 if (error) 162 return error; 163 164 return cp_old_stat(&stat, statbuf); 165 } 166 167 SYSCALL_DEFINE2(lstat, const char __user *, filename, 168 struct __old_kernel_stat __user *, statbuf) 169 { 170 struct kstat stat; 171 int error; 172 173 error = vfs_lstat(filename, &stat); 174 if (error) 175 return error; 176 177 return cp_old_stat(&stat, statbuf); 178 } 179 180 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf) 181 { 182 struct kstat stat; 183 int error = vfs_fstat(fd, &stat); 184 185 if (!error) 186 error = cp_old_stat(&stat, statbuf); 187 188 return error; 189 } 190 191 #endif /* __ARCH_WANT_OLD_STAT */ 192 193 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) 194 { 195 struct stat tmp; 196 197 #if BITS_PER_LONG == 32 198 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev)) 199 return -EOVERFLOW; 200 #else 201 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 202 return -EOVERFLOW; 203 #endif 204 205 memset(&tmp, 0, sizeof(tmp)); 206 #if BITS_PER_LONG == 32 207 tmp.st_dev = old_encode_dev(stat->dev); 208 #else 209 tmp.st_dev = new_encode_dev(stat->dev); 210 #endif 211 tmp.st_ino = stat->ino; 212 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 213 return -EOVERFLOW; 214 tmp.st_mode = stat->mode; 215 tmp.st_nlink = stat->nlink; 216 if (tmp.st_nlink != stat->nlink) 217 return -EOVERFLOW; 218 SET_UID(tmp.st_uid, stat->uid); 219 SET_GID(tmp.st_gid, stat->gid); 220 #if BITS_PER_LONG == 32 221 tmp.st_rdev = old_encode_dev(stat->rdev); 222 #else 223 tmp.st_rdev = new_encode_dev(stat->rdev); 224 #endif 225 #if BITS_PER_LONG == 32 226 if (stat->size > MAX_NON_LFS) 227 return -EOVERFLOW; 228 #endif 229 tmp.st_size = stat->size; 230 tmp.st_atime = stat->atime.tv_sec; 231 tmp.st_mtime = stat->mtime.tv_sec; 232 tmp.st_ctime = stat->ctime.tv_sec; 233 #ifdef STAT_HAVE_NSEC 234 tmp.st_atime_nsec = stat->atime.tv_nsec; 235 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 236 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 237 #endif 238 tmp.st_blocks = stat->blocks; 239 tmp.st_blksize = stat->blksize; 240 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 241 } 242 243 SYSCALL_DEFINE2(newstat, const char __user *, filename, 244 struct stat __user *, statbuf) 245 { 246 struct kstat stat; 247 int error = vfs_stat(filename, &stat); 248 249 if (error) 250 return error; 251 return cp_new_stat(&stat, statbuf); 252 } 253 254 SYSCALL_DEFINE2(newlstat, const char __user *, filename, 255 struct stat __user *, statbuf) 256 { 257 struct kstat stat; 258 int error; 259 260 error = vfs_lstat(filename, &stat); 261 if (error) 262 return error; 263 264 return cp_new_stat(&stat, statbuf); 265 } 266 267 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) 268 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename, 269 struct stat __user *, statbuf, int, flag) 270 { 271 struct kstat stat; 272 int error; 273 274 error = vfs_fstatat(dfd, filename, &stat, flag); 275 if (error) 276 return error; 277 return cp_new_stat(&stat, statbuf); 278 } 279 #endif 280 281 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf) 282 { 283 struct kstat stat; 284 int error = vfs_fstat(fd, &stat); 285 286 if (!error) 287 error = cp_new_stat(&stat, statbuf); 288 289 return error; 290 } 291 292 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, 293 char __user *, buf, int, bufsiz) 294 { 295 struct path path; 296 int error; 297 298 if (bufsiz <= 0) 299 return -EINVAL; 300 301 error = user_path_at(dfd, pathname, LOOKUP_EMPTY, &path); 302 if (!error) { 303 struct inode *inode = path.dentry->d_inode; 304 305 error = -EINVAL; 306 if (inode->i_op->readlink) { 307 error = security_inode_readlink(path.dentry); 308 if (!error) { 309 touch_atime(path.mnt, path.dentry); 310 error = inode->i_op->readlink(path.dentry, 311 buf, bufsiz); 312 } 313 } 314 path_put(&path); 315 } 316 return error; 317 } 318 319 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf, 320 int, bufsiz) 321 { 322 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 323 } 324 325 326 /* ---------- LFS-64 ----------- */ 327 #ifdef __ARCH_WANT_STAT64 328 329 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 330 { 331 struct stat64 tmp; 332 333 memset(&tmp, 0, sizeof(struct stat64)); 334 #ifdef CONFIG_MIPS 335 /* mips has weird padding, so we don't get 64 bits there */ 336 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 337 return -EOVERFLOW; 338 tmp.st_dev = new_encode_dev(stat->dev); 339 tmp.st_rdev = new_encode_dev(stat->rdev); 340 #else 341 tmp.st_dev = huge_encode_dev(stat->dev); 342 tmp.st_rdev = huge_encode_dev(stat->rdev); 343 #endif 344 tmp.st_ino = stat->ino; 345 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 346 return -EOVERFLOW; 347 #ifdef STAT64_HAS_BROKEN_ST_INO 348 tmp.__st_ino = stat->ino; 349 #endif 350 tmp.st_mode = stat->mode; 351 tmp.st_nlink = stat->nlink; 352 tmp.st_uid = stat->uid; 353 tmp.st_gid = stat->gid; 354 tmp.st_atime = stat->atime.tv_sec; 355 tmp.st_atime_nsec = stat->atime.tv_nsec; 356 tmp.st_mtime = stat->mtime.tv_sec; 357 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 358 tmp.st_ctime = stat->ctime.tv_sec; 359 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 360 tmp.st_size = stat->size; 361 tmp.st_blocks = stat->blocks; 362 tmp.st_blksize = stat->blksize; 363 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 364 } 365 366 SYSCALL_DEFINE2(stat64, const char __user *, filename, 367 struct stat64 __user *, statbuf) 368 { 369 struct kstat stat; 370 int error = vfs_stat(filename, &stat); 371 372 if (!error) 373 error = cp_new_stat64(&stat, statbuf); 374 375 return error; 376 } 377 378 SYSCALL_DEFINE2(lstat64, const char __user *, filename, 379 struct stat64 __user *, statbuf) 380 { 381 struct kstat stat; 382 int error = vfs_lstat(filename, &stat); 383 384 if (!error) 385 error = cp_new_stat64(&stat, statbuf); 386 387 return error; 388 } 389 390 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf) 391 { 392 struct kstat stat; 393 int error = vfs_fstat(fd, &stat); 394 395 if (!error) 396 error = cp_new_stat64(&stat, statbuf); 397 398 return error; 399 } 400 401 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename, 402 struct stat64 __user *, statbuf, int, flag) 403 { 404 struct kstat stat; 405 int error; 406 407 error = vfs_fstatat(dfd, filename, &stat, flag); 408 if (error) 409 return error; 410 return cp_new_stat64(&stat, statbuf); 411 } 412 #endif /* __ARCH_WANT_STAT64 */ 413 414 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */ 415 void __inode_add_bytes(struct inode *inode, loff_t bytes) 416 { 417 inode->i_blocks += bytes >> 9; 418 bytes &= 511; 419 inode->i_bytes += bytes; 420 if (inode->i_bytes >= 512) { 421 inode->i_blocks++; 422 inode->i_bytes -= 512; 423 } 424 } 425 426 void inode_add_bytes(struct inode *inode, loff_t bytes) 427 { 428 spin_lock(&inode->i_lock); 429 __inode_add_bytes(inode, bytes); 430 spin_unlock(&inode->i_lock); 431 } 432 433 EXPORT_SYMBOL(inode_add_bytes); 434 435 void inode_sub_bytes(struct inode *inode, loff_t bytes) 436 { 437 spin_lock(&inode->i_lock); 438 inode->i_blocks -= bytes >> 9; 439 bytes &= 511; 440 if (inode->i_bytes < bytes) { 441 inode->i_blocks--; 442 inode->i_bytes += 512; 443 } 444 inode->i_bytes -= bytes; 445 spin_unlock(&inode->i_lock); 446 } 447 448 EXPORT_SYMBOL(inode_sub_bytes); 449 450 loff_t inode_get_bytes(struct inode *inode) 451 { 452 loff_t ret; 453 454 spin_lock(&inode->i_lock); 455 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; 456 spin_unlock(&inode->i_lock); 457 return ret; 458 } 459 460 EXPORT_SYMBOL(inode_get_bytes); 461 462 void inode_set_bytes(struct inode *inode, loff_t bytes) 463 { 464 /* Caller is here responsible for sufficient locking 465 * (ie. inode->i_lock) */ 466 inode->i_blocks = bytes >> 9; 467 inode->i_bytes = bytes & 511; 468 } 469 470 EXPORT_SYMBOL(inode_set_bytes); 471