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->atime = inode->i_atime; 31 stat->mtime = inode->i_mtime; 32 stat->ctime = inode->i_ctime; 33 stat->size = i_size_read(inode); 34 stat->blocks = inode->i_blocks; 35 stat->blksize = (1 << inode->i_blkbits); 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) != 0) 79 goto out; 80 81 if (!(flag & AT_SYMLINK_NOFOLLOW)) 82 lookup_flags |= LOOKUP_FOLLOW; 83 84 error = user_path_at(dfd, filename, lookup_flags, &path); 85 if (error) 86 goto out; 87 88 error = vfs_getattr(path.mnt, path.dentry, stat); 89 path_put(&path); 90 out: 91 return error; 92 } 93 EXPORT_SYMBOL(vfs_fstatat); 94 95 int vfs_stat(const char __user *name, struct kstat *stat) 96 { 97 return vfs_fstatat(AT_FDCWD, name, stat, 0); 98 } 99 EXPORT_SYMBOL(vfs_stat); 100 101 int vfs_lstat(const char __user *name, struct kstat *stat) 102 { 103 return vfs_fstatat(AT_FDCWD, name, stat, AT_SYMLINK_NOFOLLOW); 104 } 105 EXPORT_SYMBOL(vfs_lstat); 106 107 108 #ifdef __ARCH_WANT_OLD_STAT 109 110 /* 111 * For backward compatibility? Maybe this should be moved 112 * into arch/i386 instead? 113 */ 114 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 115 { 116 static int warncount = 5; 117 struct __old_kernel_stat tmp; 118 119 if (warncount > 0) { 120 warncount--; 121 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 122 current->comm); 123 } else if (warncount < 0) { 124 /* it's laughable, but... */ 125 warncount = 0; 126 } 127 128 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 129 tmp.st_dev = old_encode_dev(stat->dev); 130 tmp.st_ino = stat->ino; 131 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 132 return -EOVERFLOW; 133 tmp.st_mode = stat->mode; 134 tmp.st_nlink = stat->nlink; 135 if (tmp.st_nlink != stat->nlink) 136 return -EOVERFLOW; 137 SET_UID(tmp.st_uid, stat->uid); 138 SET_GID(tmp.st_gid, stat->gid); 139 tmp.st_rdev = old_encode_dev(stat->rdev); 140 #if BITS_PER_LONG == 32 141 if (stat->size > MAX_NON_LFS) 142 return -EOVERFLOW; 143 #endif 144 tmp.st_size = stat->size; 145 tmp.st_atime = stat->atime.tv_sec; 146 tmp.st_mtime = stat->mtime.tv_sec; 147 tmp.st_ctime = stat->ctime.tv_sec; 148 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 149 } 150 151 SYSCALL_DEFINE2(stat, const char __user *, filename, 152 struct __old_kernel_stat __user *, statbuf) 153 { 154 struct kstat stat; 155 int error; 156 157 error = vfs_stat(filename, &stat); 158 if (error) 159 return error; 160 161 return cp_old_stat(&stat, statbuf); 162 } 163 164 SYSCALL_DEFINE2(lstat, const char __user *, filename, 165 struct __old_kernel_stat __user *, statbuf) 166 { 167 struct kstat stat; 168 int error; 169 170 error = vfs_lstat(filename, &stat); 171 if (error) 172 return error; 173 174 return cp_old_stat(&stat, statbuf); 175 } 176 177 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf) 178 { 179 struct kstat stat; 180 int error = vfs_fstat(fd, &stat); 181 182 if (!error) 183 error = cp_old_stat(&stat, statbuf); 184 185 return error; 186 } 187 188 #endif /* __ARCH_WANT_OLD_STAT */ 189 190 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) 191 { 192 struct stat tmp; 193 194 #if BITS_PER_LONG == 32 195 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev)) 196 return -EOVERFLOW; 197 #else 198 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 199 return -EOVERFLOW; 200 #endif 201 202 memset(&tmp, 0, sizeof(tmp)); 203 #if BITS_PER_LONG == 32 204 tmp.st_dev = old_encode_dev(stat->dev); 205 #else 206 tmp.st_dev = new_encode_dev(stat->dev); 207 #endif 208 tmp.st_ino = stat->ino; 209 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 210 return -EOVERFLOW; 211 tmp.st_mode = stat->mode; 212 tmp.st_nlink = stat->nlink; 213 if (tmp.st_nlink != stat->nlink) 214 return -EOVERFLOW; 215 SET_UID(tmp.st_uid, stat->uid); 216 SET_GID(tmp.st_gid, stat->gid); 217 #if BITS_PER_LONG == 32 218 tmp.st_rdev = old_encode_dev(stat->rdev); 219 #else 220 tmp.st_rdev = new_encode_dev(stat->rdev); 221 #endif 222 #if BITS_PER_LONG == 32 223 if (stat->size > MAX_NON_LFS) 224 return -EOVERFLOW; 225 #endif 226 tmp.st_size = stat->size; 227 tmp.st_atime = stat->atime.tv_sec; 228 tmp.st_mtime = stat->mtime.tv_sec; 229 tmp.st_ctime = stat->ctime.tv_sec; 230 #ifdef STAT_HAVE_NSEC 231 tmp.st_atime_nsec = stat->atime.tv_nsec; 232 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 233 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 234 #endif 235 tmp.st_blocks = stat->blocks; 236 tmp.st_blksize = stat->blksize; 237 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 238 } 239 240 SYSCALL_DEFINE2(newstat, const char __user *, filename, 241 struct stat __user *, statbuf) 242 { 243 struct kstat stat; 244 int error = vfs_stat(filename, &stat); 245 246 if (error) 247 return error; 248 return cp_new_stat(&stat, statbuf); 249 } 250 251 SYSCALL_DEFINE2(newlstat, const char __user *, filename, 252 struct stat __user *, statbuf) 253 { 254 struct kstat stat; 255 int error; 256 257 error = vfs_lstat(filename, &stat); 258 if (error) 259 return error; 260 261 return cp_new_stat(&stat, statbuf); 262 } 263 264 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) 265 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename, 266 struct stat __user *, statbuf, int, flag) 267 { 268 struct kstat stat; 269 int error; 270 271 error = vfs_fstatat(dfd, filename, &stat, flag); 272 if (error) 273 return error; 274 return cp_new_stat(&stat, statbuf); 275 } 276 #endif 277 278 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf) 279 { 280 struct kstat stat; 281 int error = vfs_fstat(fd, &stat); 282 283 if (!error) 284 error = cp_new_stat(&stat, statbuf); 285 286 return error; 287 } 288 289 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, 290 char __user *, buf, int, bufsiz) 291 { 292 struct path path; 293 int error; 294 295 if (bufsiz <= 0) 296 return -EINVAL; 297 298 error = user_path_at(dfd, pathname, 0, &path); 299 if (!error) { 300 struct inode *inode = path.dentry->d_inode; 301 302 error = -EINVAL; 303 if (inode->i_op->readlink) { 304 error = security_inode_readlink(path.dentry); 305 if (!error) { 306 touch_atime(path.mnt, path.dentry); 307 error = inode->i_op->readlink(path.dentry, 308 buf, bufsiz); 309 } 310 } 311 path_put(&path); 312 } 313 return error; 314 } 315 316 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf, 317 int, bufsiz) 318 { 319 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 320 } 321 322 323 /* ---------- LFS-64 ----------- */ 324 #ifdef __ARCH_WANT_STAT64 325 326 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 327 { 328 struct stat64 tmp; 329 330 memset(&tmp, 0, sizeof(struct stat64)); 331 #ifdef CONFIG_MIPS 332 /* mips has weird padding, so we don't get 64 bits there */ 333 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 334 return -EOVERFLOW; 335 tmp.st_dev = new_encode_dev(stat->dev); 336 tmp.st_rdev = new_encode_dev(stat->rdev); 337 #else 338 tmp.st_dev = huge_encode_dev(stat->dev); 339 tmp.st_rdev = huge_encode_dev(stat->rdev); 340 #endif 341 tmp.st_ino = stat->ino; 342 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 343 return -EOVERFLOW; 344 #ifdef STAT64_HAS_BROKEN_ST_INO 345 tmp.__st_ino = stat->ino; 346 #endif 347 tmp.st_mode = stat->mode; 348 tmp.st_nlink = stat->nlink; 349 tmp.st_uid = stat->uid; 350 tmp.st_gid = stat->gid; 351 tmp.st_atime = stat->atime.tv_sec; 352 tmp.st_atime_nsec = stat->atime.tv_nsec; 353 tmp.st_mtime = stat->mtime.tv_sec; 354 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 355 tmp.st_ctime = stat->ctime.tv_sec; 356 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 357 tmp.st_size = stat->size; 358 tmp.st_blocks = stat->blocks; 359 tmp.st_blksize = stat->blksize; 360 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 361 } 362 363 SYSCALL_DEFINE2(stat64, const char __user *, filename, 364 struct stat64 __user *, statbuf) 365 { 366 struct kstat stat; 367 int error = vfs_stat(filename, &stat); 368 369 if (!error) 370 error = cp_new_stat64(&stat, statbuf); 371 372 return error; 373 } 374 375 SYSCALL_DEFINE2(lstat64, const char __user *, filename, 376 struct stat64 __user *, statbuf) 377 { 378 struct kstat stat; 379 int error = vfs_lstat(filename, &stat); 380 381 if (!error) 382 error = cp_new_stat64(&stat, statbuf); 383 384 return error; 385 } 386 387 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf) 388 { 389 struct kstat stat; 390 int error = vfs_fstat(fd, &stat); 391 392 if (!error) 393 error = cp_new_stat64(&stat, statbuf); 394 395 return error; 396 } 397 398 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename, 399 struct stat64 __user *, statbuf, int, flag) 400 { 401 struct kstat stat; 402 int error; 403 404 error = vfs_fstatat(dfd, filename, &stat, flag); 405 if (error) 406 return error; 407 return cp_new_stat64(&stat, statbuf); 408 } 409 #endif /* __ARCH_WANT_STAT64 */ 410 411 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */ 412 void __inode_add_bytes(struct inode *inode, loff_t bytes) 413 { 414 inode->i_blocks += bytes >> 9; 415 bytes &= 511; 416 inode->i_bytes += bytes; 417 if (inode->i_bytes >= 512) { 418 inode->i_blocks++; 419 inode->i_bytes -= 512; 420 } 421 } 422 423 void inode_add_bytes(struct inode *inode, loff_t bytes) 424 { 425 spin_lock(&inode->i_lock); 426 __inode_add_bytes(inode, bytes); 427 spin_unlock(&inode->i_lock); 428 } 429 430 EXPORT_SYMBOL(inode_add_bytes); 431 432 void inode_sub_bytes(struct inode *inode, loff_t bytes) 433 { 434 spin_lock(&inode->i_lock); 435 inode->i_blocks -= bytes >> 9; 436 bytes &= 511; 437 if (inode->i_bytes < bytes) { 438 inode->i_blocks--; 439 inode->i_bytes += 512; 440 } 441 inode->i_bytes -= bytes; 442 spin_unlock(&inode->i_lock); 443 } 444 445 EXPORT_SYMBOL(inode_sub_bytes); 446 447 loff_t inode_get_bytes(struct inode *inode) 448 { 449 loff_t ret; 450 451 spin_lock(&inode->i_lock); 452 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; 453 spin_unlock(&inode->i_lock); 454 return ret; 455 } 456 457 EXPORT_SYMBOL(inode_get_bytes); 458 459 void inode_set_bytes(struct inode *inode, loff_t bytes) 460 { 461 /* Caller is here responsible for sufficient locking 462 * (ie. inode->i_lock) */ 463 inode->i_blocks = bytes >> 9; 464 inode->i_bytes = bytes & 511; 465 } 466 467 EXPORT_SYMBOL(inode_set_bytes); 468