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_stat_fd(int dfd, char __user *name, struct kstat *stat) 59 { 60 struct nameidata nd; 61 int error; 62 63 error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd); 64 if (!error) { 65 error = vfs_getattr(nd.mnt, nd.dentry, stat); 66 path_release(&nd); 67 } 68 return error; 69 } 70 71 int vfs_stat(char __user *name, struct kstat *stat) 72 { 73 return vfs_stat_fd(AT_FDCWD, name, stat); 74 } 75 76 EXPORT_SYMBOL(vfs_stat); 77 78 int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat) 79 { 80 struct nameidata nd; 81 int error; 82 83 error = __user_walk_fd(dfd, name, 0, &nd); 84 if (!error) { 85 error = vfs_getattr(nd.mnt, nd.dentry, stat); 86 path_release(&nd); 87 } 88 return error; 89 } 90 91 int vfs_lstat(char __user *name, struct kstat *stat) 92 { 93 return vfs_lstat_fd(AT_FDCWD, name, stat); 94 } 95 96 EXPORT_SYMBOL(vfs_lstat); 97 98 int vfs_fstat(unsigned int fd, struct kstat *stat) 99 { 100 struct file *f = fget(fd); 101 int error = -EBADF; 102 103 if (f) { 104 error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat); 105 fput(f); 106 } 107 return error; 108 } 109 110 EXPORT_SYMBOL(vfs_fstat); 111 112 #ifdef __ARCH_WANT_OLD_STAT 113 114 /* 115 * For backward compatibility? Maybe this should be moved 116 * into arch/i386 instead? 117 */ 118 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 119 { 120 static int warncount = 5; 121 struct __old_kernel_stat tmp; 122 123 if (warncount > 0) { 124 warncount--; 125 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 126 current->comm); 127 } else if (warncount < 0) { 128 /* it's laughable, but... */ 129 warncount = 0; 130 } 131 132 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 133 tmp.st_dev = old_encode_dev(stat->dev); 134 tmp.st_ino = stat->ino; 135 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 136 return -EOVERFLOW; 137 tmp.st_mode = stat->mode; 138 tmp.st_nlink = stat->nlink; 139 if (tmp.st_nlink != stat->nlink) 140 return -EOVERFLOW; 141 SET_UID(tmp.st_uid, stat->uid); 142 SET_GID(tmp.st_gid, stat->gid); 143 tmp.st_rdev = old_encode_dev(stat->rdev); 144 #if BITS_PER_LONG == 32 145 if (stat->size > MAX_NON_LFS) 146 return -EOVERFLOW; 147 #endif 148 tmp.st_size = stat->size; 149 tmp.st_atime = stat->atime.tv_sec; 150 tmp.st_mtime = stat->mtime.tv_sec; 151 tmp.st_ctime = stat->ctime.tv_sec; 152 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 153 } 154 155 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf) 156 { 157 struct kstat stat; 158 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 159 160 if (!error) 161 error = cp_old_stat(&stat, statbuf); 162 163 return error; 164 } 165 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf) 166 { 167 struct kstat stat; 168 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 169 170 if (!error) 171 error = cp_old_stat(&stat, statbuf); 172 173 return error; 174 } 175 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf) 176 { 177 struct kstat stat; 178 int error = vfs_fstat(fd, &stat); 179 180 if (!error) 181 error = cp_old_stat(&stat, statbuf); 182 183 return error; 184 } 185 186 #endif /* __ARCH_WANT_OLD_STAT */ 187 188 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) 189 { 190 struct stat tmp; 191 192 #if BITS_PER_LONG == 32 193 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev)) 194 return -EOVERFLOW; 195 #else 196 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 197 return -EOVERFLOW; 198 #endif 199 200 memset(&tmp, 0, sizeof(tmp)); 201 #if BITS_PER_LONG == 32 202 tmp.st_dev = old_encode_dev(stat->dev); 203 #else 204 tmp.st_dev = new_encode_dev(stat->dev); 205 #endif 206 tmp.st_ino = stat->ino; 207 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 208 return -EOVERFLOW; 209 tmp.st_mode = stat->mode; 210 tmp.st_nlink = stat->nlink; 211 if (tmp.st_nlink != stat->nlink) 212 return -EOVERFLOW; 213 SET_UID(tmp.st_uid, stat->uid); 214 SET_GID(tmp.st_gid, stat->gid); 215 #if BITS_PER_LONG == 32 216 tmp.st_rdev = old_encode_dev(stat->rdev); 217 #else 218 tmp.st_rdev = new_encode_dev(stat->rdev); 219 #endif 220 #if BITS_PER_LONG == 32 221 if (stat->size > MAX_NON_LFS) 222 return -EOVERFLOW; 223 #endif 224 tmp.st_size = stat->size; 225 tmp.st_atime = stat->atime.tv_sec; 226 tmp.st_mtime = stat->mtime.tv_sec; 227 tmp.st_ctime = stat->ctime.tv_sec; 228 #ifdef STAT_HAVE_NSEC 229 tmp.st_atime_nsec = stat->atime.tv_nsec; 230 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 231 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 232 #endif 233 tmp.st_blocks = stat->blocks; 234 tmp.st_blksize = stat->blksize; 235 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 236 } 237 238 asmlinkage long sys_newstat(char __user *filename, struct stat __user *statbuf) 239 { 240 struct kstat stat; 241 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 242 243 if (!error) 244 error = cp_new_stat(&stat, statbuf); 245 246 return error; 247 } 248 249 asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf) 250 { 251 struct kstat stat; 252 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 253 254 if (!error) 255 error = cp_new_stat(&stat, statbuf); 256 257 return error; 258 } 259 260 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) 261 asmlinkage long sys_newfstatat(int dfd, char __user *filename, 262 struct stat __user *statbuf, int flag) 263 { 264 struct kstat stat; 265 int error = -EINVAL; 266 267 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 268 goto out; 269 270 if (flag & AT_SYMLINK_NOFOLLOW) 271 error = vfs_lstat_fd(dfd, filename, &stat); 272 else 273 error = vfs_stat_fd(dfd, filename, &stat); 274 275 if (!error) 276 error = cp_new_stat(&stat, statbuf); 277 278 out: 279 return error; 280 } 281 #endif 282 283 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf) 284 { 285 struct kstat stat; 286 int error = vfs_fstat(fd, &stat); 287 288 if (!error) 289 error = cp_new_stat(&stat, statbuf); 290 291 return error; 292 } 293 294 asmlinkage long sys_readlinkat(int dfd, const char __user *path, 295 char __user *buf, int bufsiz) 296 { 297 struct nameidata nd; 298 int error; 299 300 if (bufsiz <= 0) 301 return -EINVAL; 302 303 error = __user_walk_fd(dfd, path, 0, &nd); 304 if (!error) { 305 struct inode * inode = nd.dentry->d_inode; 306 307 error = -EINVAL; 308 if (inode->i_op && inode->i_op->readlink) { 309 error = security_inode_readlink(nd.dentry); 310 if (!error) { 311 touch_atime(nd.mnt, nd.dentry); 312 error = inode->i_op->readlink(nd.dentry, buf, bufsiz); 313 } 314 } 315 path_release(&nd); 316 } 317 return error; 318 } 319 320 asmlinkage long sys_readlink(const char __user *path, char __user *buf, 321 int bufsiz) 322 { 323 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 324 } 325 326 327 /* ---------- LFS-64 ----------- */ 328 #ifdef __ARCH_WANT_STAT64 329 330 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 331 { 332 struct stat64 tmp; 333 334 memset(&tmp, 0, sizeof(struct stat64)); 335 #ifdef CONFIG_MIPS 336 /* mips has weird padding, so we don't get 64 bits there */ 337 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 338 return -EOVERFLOW; 339 tmp.st_dev = new_encode_dev(stat->dev); 340 tmp.st_rdev = new_encode_dev(stat->rdev); 341 #else 342 tmp.st_dev = huge_encode_dev(stat->dev); 343 tmp.st_rdev = huge_encode_dev(stat->rdev); 344 #endif 345 tmp.st_ino = stat->ino; 346 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 347 return -EOVERFLOW; 348 #ifdef STAT64_HAS_BROKEN_ST_INO 349 tmp.__st_ino = stat->ino; 350 #endif 351 tmp.st_mode = stat->mode; 352 tmp.st_nlink = stat->nlink; 353 tmp.st_uid = stat->uid; 354 tmp.st_gid = stat->gid; 355 tmp.st_atime = stat->atime.tv_sec; 356 tmp.st_atime_nsec = stat->atime.tv_nsec; 357 tmp.st_mtime = stat->mtime.tv_sec; 358 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 359 tmp.st_ctime = stat->ctime.tv_sec; 360 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 361 tmp.st_size = stat->size; 362 tmp.st_blocks = stat->blocks; 363 tmp.st_blksize = stat->blksize; 364 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 365 } 366 367 asmlinkage long sys_stat64(char __user * filename, 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 asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf) 378 { 379 struct kstat stat; 380 int error = vfs_lstat(filename, &stat); 381 382 if (!error) 383 error = cp_new_stat64(&stat, statbuf); 384 385 return error; 386 } 387 asmlinkage long sys_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 asmlinkage long sys_fstatat64(int dfd, char __user *filename, 399 struct stat64 __user *statbuf, int flag) 400 { 401 struct kstat stat; 402 int error = -EINVAL; 403 404 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 405 goto out; 406 407 if (flag & AT_SYMLINK_NOFOLLOW) 408 error = vfs_lstat_fd(dfd, filename, &stat); 409 else 410 error = vfs_stat_fd(dfd, filename, &stat); 411 412 if (!error) 413 error = cp_new_stat64(&stat, statbuf); 414 415 out: 416 return error; 417 } 418 #endif /* __ARCH_WANT_STAT64 */ 419 420 void inode_add_bytes(struct inode *inode, loff_t bytes) 421 { 422 spin_lock(&inode->i_lock); 423 inode->i_blocks += bytes >> 9; 424 bytes &= 511; 425 inode->i_bytes += bytes; 426 if (inode->i_bytes >= 512) { 427 inode->i_blocks++; 428 inode->i_bytes -= 512; 429 } 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