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 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 = inode->i_blksize; 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 if (!stat->blksize) { 54 struct super_block *s = inode->i_sb; 55 unsigned blocks; 56 blocks = (stat->size+s->s_blocksize-1) >> s->s_blocksize_bits; 57 stat->blocks = (s->s_blocksize / 512) * blocks; 58 stat->blksize = s->s_blocksize; 59 } 60 return 0; 61 } 62 63 EXPORT_SYMBOL(vfs_getattr); 64 65 int vfs_stat_fd(int dfd, char __user *name, struct kstat *stat) 66 { 67 struct nameidata nd; 68 int error; 69 70 error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd); 71 if (!error) { 72 error = vfs_getattr(nd.mnt, nd.dentry, stat); 73 path_release(&nd); 74 } 75 return error; 76 } 77 78 int vfs_stat(char __user *name, struct kstat *stat) 79 { 80 return vfs_stat_fd(AT_FDCWD, name, stat); 81 } 82 83 EXPORT_SYMBOL(vfs_stat); 84 85 int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat) 86 { 87 struct nameidata nd; 88 int error; 89 90 error = __user_walk_fd(dfd, name, 0, &nd); 91 if (!error) { 92 error = vfs_getattr(nd.mnt, nd.dentry, stat); 93 path_release(&nd); 94 } 95 return error; 96 } 97 98 int vfs_lstat(char __user *name, struct kstat *stat) 99 { 100 return vfs_lstat_fd(AT_FDCWD, name, stat); 101 } 102 103 EXPORT_SYMBOL(vfs_lstat); 104 105 int vfs_fstat(unsigned int fd, struct kstat *stat) 106 { 107 struct file *f = fget(fd); 108 int error = -EBADF; 109 110 if (f) { 111 error = vfs_getattr(f->f_vfsmnt, f->f_dentry, stat); 112 fput(f); 113 } 114 return error; 115 } 116 117 EXPORT_SYMBOL(vfs_fstat); 118 119 #ifdef __ARCH_WANT_OLD_STAT 120 121 /* 122 * For backward compatibility? Maybe this should be moved 123 * into arch/i386 instead? 124 */ 125 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf) 126 { 127 static int warncount = 5; 128 struct __old_kernel_stat tmp; 129 130 if (warncount > 0) { 131 warncount--; 132 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n", 133 current->comm); 134 } else if (warncount < 0) { 135 /* it's laughable, but... */ 136 warncount = 0; 137 } 138 139 memset(&tmp, 0, sizeof(struct __old_kernel_stat)); 140 tmp.st_dev = old_encode_dev(stat->dev); 141 tmp.st_ino = stat->ino; 142 tmp.st_mode = stat->mode; 143 tmp.st_nlink = stat->nlink; 144 if (tmp.st_nlink != stat->nlink) 145 return -EOVERFLOW; 146 SET_UID(tmp.st_uid, stat->uid); 147 SET_GID(tmp.st_gid, stat->gid); 148 tmp.st_rdev = old_encode_dev(stat->rdev); 149 #if BITS_PER_LONG == 32 150 if (stat->size > MAX_NON_LFS) 151 return -EOVERFLOW; 152 #endif 153 tmp.st_size = stat->size; 154 tmp.st_atime = stat->atime.tv_sec; 155 tmp.st_mtime = stat->mtime.tv_sec; 156 tmp.st_ctime = stat->ctime.tv_sec; 157 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 158 } 159 160 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf) 161 { 162 struct kstat stat; 163 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 164 165 if (!error) 166 error = cp_old_stat(&stat, statbuf); 167 168 return error; 169 } 170 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf) 171 { 172 struct kstat stat; 173 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 174 175 if (!error) 176 error = cp_old_stat(&stat, statbuf); 177 178 return error; 179 } 180 asmlinkage long sys_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 tmp.st_mode = stat->mode; 213 tmp.st_nlink = stat->nlink; 214 if (tmp.st_nlink != stat->nlink) 215 return -EOVERFLOW; 216 SET_UID(tmp.st_uid, stat->uid); 217 SET_GID(tmp.st_gid, stat->gid); 218 #if BITS_PER_LONG == 32 219 tmp.st_rdev = old_encode_dev(stat->rdev); 220 #else 221 tmp.st_rdev = new_encode_dev(stat->rdev); 222 #endif 223 #if BITS_PER_LONG == 32 224 if (stat->size > MAX_NON_LFS) 225 return -EOVERFLOW; 226 #endif 227 tmp.st_size = stat->size; 228 tmp.st_atime = stat->atime.tv_sec; 229 tmp.st_mtime = stat->mtime.tv_sec; 230 tmp.st_ctime = stat->ctime.tv_sec; 231 #ifdef STAT_HAVE_NSEC 232 tmp.st_atime_nsec = stat->atime.tv_nsec; 233 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 234 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 235 #endif 236 tmp.st_blocks = stat->blocks; 237 tmp.st_blksize = stat->blksize; 238 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 239 } 240 241 asmlinkage long sys_newstat(char __user *filename, struct stat __user *statbuf) 242 { 243 struct kstat stat; 244 int error = vfs_stat_fd(AT_FDCWD, filename, &stat); 245 246 if (!error) 247 error = cp_new_stat(&stat, statbuf); 248 249 return error; 250 } 251 252 asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf) 253 { 254 struct kstat stat; 255 int error = vfs_lstat_fd(AT_FDCWD, filename, &stat); 256 257 if (!error) 258 error = cp_new_stat(&stat, statbuf); 259 260 return error; 261 } 262 263 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT) 264 asmlinkage long sys_newfstatat(int dfd, char __user *filename, 265 struct stat __user *statbuf, int flag) 266 { 267 struct kstat stat; 268 int error = -EINVAL; 269 270 if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0) 271 goto out; 272 273 if (flag & AT_SYMLINK_NOFOLLOW) 274 error = vfs_lstat_fd(dfd, filename, &stat); 275 else 276 error = vfs_stat_fd(dfd, filename, &stat); 277 278 if (!error) 279 error = cp_new_stat(&stat, statbuf); 280 281 out: 282 return error; 283 } 284 #endif 285 286 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf) 287 { 288 struct kstat stat; 289 int error = vfs_fstat(fd, &stat); 290 291 if (!error) 292 error = cp_new_stat(&stat, statbuf); 293 294 return error; 295 } 296 297 asmlinkage long sys_readlinkat(int dfd, const char __user *path, 298 char __user *buf, int bufsiz) 299 { 300 struct nameidata nd; 301 int error; 302 303 if (bufsiz <= 0) 304 return -EINVAL; 305 306 error = __user_walk_fd(dfd, path, 0, &nd); 307 if (!error) { 308 struct inode * inode = nd.dentry->d_inode; 309 310 error = -EINVAL; 311 if (inode->i_op && inode->i_op->readlink) { 312 error = security_inode_readlink(nd.dentry); 313 if (!error) { 314 touch_atime(nd.mnt, nd.dentry); 315 error = inode->i_op->readlink(nd.dentry, buf, bufsiz); 316 } 317 } 318 path_release(&nd); 319 } 320 return error; 321 } 322 323 asmlinkage long sys_readlink(const char __user *path, char __user *buf, 324 int bufsiz) 325 { 326 return sys_readlinkat(AT_FDCWD, path, buf, bufsiz); 327 } 328 329 330 /* ---------- LFS-64 ----------- */ 331 #ifdef __ARCH_WANT_STAT64 332 333 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf) 334 { 335 struct stat64 tmp; 336 337 memset(&tmp, 0, sizeof(struct stat64)); 338 #ifdef CONFIG_MIPS 339 /* mips has weird padding, so we don't get 64 bits there */ 340 if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev)) 341 return -EOVERFLOW; 342 tmp.st_dev = new_encode_dev(stat->dev); 343 tmp.st_rdev = new_encode_dev(stat->rdev); 344 #else 345 tmp.st_dev = huge_encode_dev(stat->dev); 346 tmp.st_rdev = huge_encode_dev(stat->rdev); 347 #endif 348 tmp.st_ino = stat->ino; 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