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/smp_lock.h> 12 #include <linux/highuid.h> 13 #include <linux/fs.h> 14 #include <linux/namei.h> 15 #include <linux/security.h> 16 #include <linux/syscalls.h> 17 #include <linux/pagemap.h> 18 19 #include <asm/uaccess.h> 20 #include <asm/unistd.h> 21 22 void generic_fillattr(struct inode *inode, struct kstat *stat) 23 { 24 stat->dev = inode->i_sb->s_dev; 25 stat->ino = inode->i_ino; 26 stat->mode = inode->i_mode; 27 stat->nlink = inode->i_nlink; 28 stat->uid = inode->i_uid; 29 stat->gid = inode->i_gid; 30 stat->rdev = inode->i_rdev; 31 stat->atime = inode->i_atime; 32 stat->mtime = inode->i_mtime; 33 stat->ctime = inode->i_ctime; 34 stat->size = i_size_read(inode); 35 stat->blocks = inode->i_blocks; 36 stat->blksize = (1 << inode->i_blkbits); 37 } 38 39 EXPORT_SYMBOL(generic_fillattr); 40 41 int vfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 42 { 43 struct inode *inode = dentry->d_inode; 44 int retval; 45 46 retval = security_inode_getattr(mnt, dentry); 47 if (retval) 48 return retval; 49 50 if (inode->i_op->getattr) 51 return inode->i_op->getattr(mnt, dentry, stat); 52 53 generic_fillattr(inode, stat); 54 return 0; 55 } 56 57 EXPORT_SYMBOL(vfs_getattr); 58 59 int vfs_stat_fd(int dfd, char __user *name, struct kstat *stat) 60 { 61 struct nameidata nd; 62 int error; 63 64 error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd); 65 if (!error) { 66 error = vfs_getattr(nd.mnt, nd.dentry, stat); 67 path_release(&nd); 68 } 69 return error; 70 } 71 72 int vfs_stat(char __user *name, struct kstat *stat) 73 { 74 return vfs_stat_fd(AT_FDCWD, name, stat); 75 } 76 77 EXPORT_SYMBOL(vfs_stat); 78 79 int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat) 80 { 81 struct nameidata nd; 82 int error; 83 84 error = __user_walk_fd(dfd, name, 0, &nd); 85 if (!error) { 86 error = vfs_getattr(nd.mnt, nd.dentry, stat); 87 path_release(&nd); 88 } 89 return error; 90 } 91 92 int vfs_lstat(char __user *name, struct kstat *stat) 93 { 94 return vfs_lstat_fd(AT_FDCWD, name, stat); 95 } 96 97 EXPORT_SYMBOL(vfs_lstat); 98 99 int vfs_fstat(unsigned int fd, struct kstat *stat) 100 { 101 struct file *f = fget(fd); 102 int error = -EBADF; 103 104 if (f) { 105 error = vfs_getattr(f->f_path.mnt, f->f_path.dentry, stat); 106 fput(f); 107 } 108 return error; 109 } 110 111 EXPORT_SYMBOL(vfs_fstat); 112 113 #ifdef __ARCH_WANT_OLD_STAT 114 115 /* 116 * For backward compatibility? Maybe this should be moved 117 * into arch/i386 instead? 118 */ 119 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 120 { 121 static int warncount = 5; 122 struct __old_kernel_stat tmp; 123 124 if (warncount > 0) { 125 warncount--; 126 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 127 current->comm); 128 } else if (warncount < 0) { 129 /* it's laughable, but... */ 130 warncount = 0; 131 } 132 133 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 134 tmp.st_dev = old_encode_dev(stat->dev); 135 tmp.st_ino = stat->ino; 136 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 137 return -EOVERFLOW; 138 tmp.st_mode = stat->mode; 139 tmp.st_nlink = stat->nlink; 140 if (tmp.st_nlink != stat->nlink) 141 return -EOVERFLOW; 142 SET_UID(tmp.st_uid, stat->uid); 143 SET_GID(tmp.st_gid, stat->gid); 144 tmp.st_rdev = old_encode_dev(stat->rdev); 145 #if BITS_PER_LONG == 32 146 if (stat->size > MAX_NON_LFS) 147 return -EOVERFLOW; 148 #endif 149 tmp.st_size = stat->size; 150 tmp.st_atime = stat->atime.tv_sec; 151 tmp.st_mtime = stat->mtime.tv_sec; 152 tmp.st_ctime = stat->ctime.tv_sec; 153 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 154 } 155 156 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf) 157 { 158 struct kstat stat; 159 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 160 161 if (!error) 162 error = cp_old_stat(&stat, statbuf); 163 164 return error; 165 } 166 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf) 167 { 168 struct kstat stat; 169 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 170 171 if (!error) 172 error = cp_old_stat(&stat, statbuf); 173 174 return error; 175 } 176 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf) 177 { 178 struct kstat stat; 179 int error = vfs_fstat(fd, &stat); 180 181 if (!error) 182 error = cp_old_stat(&stat, statbuf); 183 184 return error; 185 } 186 187 #endif /* __ARCH_WANT_OLD_STAT */ 188 189 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf) 190 { 191 struct stat tmp; 192 193 #if BITS_PER_LONG == 32 194 if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev)) 195 return -EOVERFLOW; 196 #else 197 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 198 return -EOVERFLOW; 199 #endif 200 201 memset(&tmp, 0, sizeof(tmp)); 202 #if BITS_PER_LONG == 32 203 tmp.st_dev = old_encode_dev(stat->dev); 204 #else 205 tmp.st_dev = new_encode_dev(stat->dev); 206 #endif 207 tmp.st_ino = stat->ino; 208 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 209 return -EOVERFLOW; 210 tmp.st_mode = stat->mode; 211 tmp.st_nlink = stat->nlink; 212 if (tmp.st_nlink != stat->nlink) 213 return -EOVERFLOW; 214 SET_UID(tmp.st_uid, stat->uid); 215 SET_GID(tmp.st_gid, stat->gid); 216 #if BITS_PER_LONG == 32 217 tmp.st_rdev = old_encode_dev(stat->rdev); 218 #else 219 tmp.st_rdev = new_encode_dev(stat->rdev); 220 #endif 221 #if BITS_PER_LONG == 32 222 if (stat->size > MAX_NON_LFS) 223 return -EOVERFLOW; 224 #endif 225 tmp.st_size = stat->size; 226 tmp.st_atime = stat->atime.tv_sec; 227 tmp.st_mtime = stat->mtime.tv_sec; 228 tmp.st_ctime = stat->ctime.tv_sec; 229 #ifdef STAT_HAVE_NSEC 230 tmp.st_atime_nsec = stat->atime.tv_nsec; 231 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 232 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 233 #endif 234 tmp.st_blocks = stat->blocks; 235 tmp.st_blksize = stat->blksize; 236 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 237 } 238 239 asmlinkage long sys_newstat(char __user *filename, struct stat __user *statbuf) 240 { 241 struct kstat stat; 242 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 243 244 if (!error) 245 error = cp_new_stat(&stat, statbuf); 246 247 return error; 248 } 249 250 asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf) 251 { 252 struct kstat stat; 253 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 254 255 if (!error) 256 error = cp_new_stat(&stat, statbuf); 257 258 return error; 259 } 260 261 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) 262 asmlinkage long sys_newfstatat(int dfd, char __user *filename, 263 struct stat __user *statbuf, int flag) 264 { 265 struct kstat stat; 266 int error = -EINVAL; 267 268 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 269 goto out; 270 271 if (flag & AT_SYMLINK_NOFOLLOW) 272 error = vfs_lstat_fd(dfd, filename, &stat); 273 else 274 error = vfs_stat_fd(dfd, filename, &stat); 275 276 if (!error) 277 error = cp_new_stat(&stat, statbuf); 278 279 out: 280 return error; 281 } 282 #endif 283 284 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf) 285 { 286 struct kstat stat; 287 int error = vfs_fstat(fd, &stat); 288 289 if (!error) 290 error = cp_new_stat(&stat, statbuf); 291 292 return error; 293 } 294 295 asmlinkage long sys_readlinkat(int dfd, const char __user *path, 296 char __user *buf, int bufsiz) 297 { 298 struct nameidata nd; 299 int error; 300 301 if (bufsiz <= 0) 302 return -EINVAL; 303 304 error = __user_walk_fd(dfd, path, 0, &nd); 305 if (!error) { 306 struct inode * inode = nd.dentry->d_inode; 307 308 error = -EINVAL; 309 if (inode->i_op && inode->i_op->readlink) { 310 error = security_inode_readlink(nd.dentry); 311 if (!error) { 312 touch_atime(nd.mnt, nd.dentry); 313 error = inode->i_op->readlink(nd.dentry, buf, bufsiz); 314 } 315 } 316 path_release(&nd); 317 } 318 return error; 319 } 320 321 asmlinkage long sys_readlink(const char __user *path, char __user *buf, 322 int bufsiz) 323 { 324 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 325 } 326 327 328 /* ---------- LFS-64 ----------- */ 329 #ifdef __ARCH_WANT_STAT64 330 331 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 332 { 333 struct stat64 tmp; 334 335 memset(&tmp, 0, sizeof(struct stat64)); 336 #ifdef CONFIG_MIPS 337 /* mips has weird padding, so we don't get 64 bits there */ 338 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 339 return -EOVERFLOW; 340 tmp.st_dev = new_encode_dev(stat->dev); 341 tmp.st_rdev = new_encode_dev(stat->rdev); 342 #else 343 tmp.st_dev = huge_encode_dev(stat->dev); 344 tmp.st_rdev = huge_encode_dev(stat->rdev); 345 #endif 346 tmp.st_ino = stat->ino; 347 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino) 348 return -EOVERFLOW; 349 #ifdef STAT64_HAS_BROKEN_ST_INO 350 tmp.__st_ino = stat->ino; 351 #endif 352 tmp.st_mode = stat->mode; 353 tmp.st_nlink = stat->nlink; 354 tmp.st_uid = stat->uid; 355 tmp.st_gid = stat->gid; 356 tmp.st_atime = stat->atime.tv_sec; 357 tmp.st_atime_nsec = stat->atime.tv_nsec; 358 tmp.st_mtime = stat->mtime.tv_sec; 359 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 360 tmp.st_ctime = stat->ctime.tv_sec; 361 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 362 tmp.st_size = stat->size; 363 tmp.st_blocks = stat->blocks; 364 tmp.st_blksize = stat->blksize; 365 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 366 } 367 368 asmlinkage long sys_stat64(char __user * filename, struct stat64 __user * statbuf) 369 { 370 struct kstat stat; 371 int error = vfs_stat(filename, &stat); 372 373 if (!error) 374 error = cp_new_stat64(&stat, statbuf); 375 376 return error; 377 } 378 asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf) 379 { 380 struct kstat stat; 381 int error = vfs_lstat(filename, &stat); 382 383 if (!error) 384 error = cp_new_stat64(&stat, statbuf); 385 386 return error; 387 } 388 asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf) 389 { 390 struct kstat stat; 391 int error = vfs_fstat(fd, &stat); 392 393 if (!error) 394 error = cp_new_stat64(&stat, statbuf); 395 396 return error; 397 } 398 399 asmlinkage long sys_fstatat64(int dfd, char __user *filename, 400 struct stat64 __user *statbuf, int flag) 401 { 402 struct kstat stat; 403 int error = -EINVAL; 404 405 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 406 goto out; 407 408 if (flag & AT_SYMLINK_NOFOLLOW) 409 error = vfs_lstat_fd(dfd, filename, &stat); 410 else 411 error = vfs_stat_fd(dfd, filename, &stat); 412 413 if (!error) 414 error = cp_new_stat64(&stat, statbuf); 415 416 out: 417 return error; 418 } 419 #endif /* __ARCH_WANT_STAT64 */ 420 421 void inode_add_bytes(struct inode *inode, loff_t bytes) 422 { 423 spin_lock(&inode->i_lock); 424 inode->i_blocks += bytes >> 9; 425 bytes &= 511; 426 inode->i_bytes += bytes; 427 if (inode->i_bytes >= 512) { 428 inode->i_blocks++; 429 inode->i_bytes -= 512; 430 } 431 spin_unlock(&inode->i_lock); 432 } 433 434 EXPORT_SYMBOL(inode_add_bytes); 435 436 void inode_sub_bytes(struct inode *inode, loff_t bytes) 437 { 438 spin_lock(&inode->i_lock); 439 inode->i_blocks -= bytes >> 9; 440 bytes &= 511; 441 if (inode->i_bytes < bytes) { 442 inode->i_blocks--; 443 inode->i_bytes += 512; 444 } 445 inode->i_bytes -= bytes; 446 spin_unlock(&inode->i_lock); 447 } 448 449 EXPORT_SYMBOL(inode_sub_bytes); 450 451 loff_t inode_get_bytes(struct inode *inode) 452 { 453 loff_t ret; 454 455 spin_lock(&inode->i_lock); 456 ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes; 457 spin_unlock(&inode->i_lock); 458 return ret; 459 } 460 461 EXPORT_SYMBOL(inode_get_bytes); 462 463 void inode_set_bytes(struct inode *inode, loff_t bytes) 464 { 465 /* Caller is here responsible for sufficient locking 466 * (ie. inode->i_lock) */ 467 inode->i_blocks = bytes >> 9; 468 inode->i_bytes = bytes & 511; 469 } 470 471 EXPORT_SYMBOL(inode_set_bytes); 472