fs/stat.c

   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         if (!stat->blksize) {
  55                 struct super_block *s = inode->i_sb;
  56                 unsigned blocks;
  57                 blocks = (stat->size+s->s_blocksize-1) >> s->s_blocksize_bits;
  58                 stat->blocks = (s->s_blocksize / 512) * blocks;
  59                 stat->blksize = s->s_blocksize;
  60         }
  61         return 0;
  62 }
  63
  64 EXPORT_SYMBOL(vfs_getattr);
  65
  66 int vfs_stat_fd(int dfd, char __user *name, struct kstat *stat)
  67 {
  68         struct nameidata nd;
  69         int error;
  70
  71         error = __user_walk_fd(dfd, name, LOOKUP_FOLLOW, &nd);
  72         if (!error) {
  73                 error = vfs_getattr(nd.mnt, nd.dentry, stat);
  74                 path_release(&nd);
  75         }
  76         return error;
  77 }
  78
  79 int vfs_stat(char __user *name, struct kstat *stat)
  80 {
  81         return vfs_stat_fd(AT_FDCWD, name, stat);
  82 }
  83
  84 EXPORT_SYMBOL(vfs_stat);
  85
  86 int vfs_lstat_fd(int dfd, char __user *name, struct kstat *stat)
  87 {
  88         struct nameidata nd;
  89         int error;
  90
  91         error = __user_walk_fd(dfd, name, 0, &nd);
  92         if (!error) {
  93                 error = vfs_getattr(nd.mnt, nd.dentry, stat);
  94                 path_release(&nd);
  95         }
  96         return error;
  97 }
  98
  99 int vfs_lstat(char __user *name, struct kstat *stat)
 100 {
 101         return vfs_lstat_fd(AT_FDCWD, name, stat);
 102 }
 103
 104 EXPORT_SYMBOL(vfs_lstat);
 105
 106 int vfs_fstat(unsigned int fd, struct kstat *stat)
 107 {
 108         struct file *f = fget(fd);
 109         int error = -EBADF;
 110
 111         if (f) {
 112                 error = vfs_getattr(f->f_vfsmnt, f->f_dentry, stat);
 113                 fput(f);
 114         }
 115         return error;
 116 }
 117
 118 EXPORT_SYMBOL(vfs_fstat);
 119
 120 #ifdef __ARCH_WANT_OLD_STAT
 121
 122 /*
 123  * For backward compatibility?  Maybe this should be moved
 124  * into arch/i386 instead?
 125  */
 126 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
 127 {
 128         static int warncount = 5;
 129         struct __old_kernel_stat tmp;
 130
 131         if (warncount > 0) {
 132                 warncount--;
 133                 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
 134                         current->comm);
 135         } else if (warncount < 0) {
 136                 /* it's laughable, but... */
 137                 warncount = 0;
 138         }
 139
 140         memset(&tmp, 0, sizeof(struct __old_kernel_stat));
 141         tmp.st_dev = old_encode_dev(stat->dev);
 142         tmp.st_ino = stat->ino;
 143         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 144                 return -EOVERFLOW;
 145         tmp.st_mode = stat->mode;
 146         tmp.st_nlink = stat->nlink;
 147         if (tmp.st_nlink != stat->nlink)
 148                 return -EOVERFLOW;
 149         SET_UID(tmp.st_uid, stat->uid);
 150         SET_GID(tmp.st_gid, stat->gid);
 151         tmp.st_rdev = old_encode_dev(stat->rdev);
 152 #if BITS_PER_LONG == 32
 153         if (stat->size > MAX_NON_LFS)
 154                 return -EOVERFLOW;
 155 #endif
 156         tmp.st_size = stat->size;
 157         tmp.st_atime = stat->atime.tv_sec;
 158         tmp.st_mtime = stat->mtime.tv_sec;
 159         tmp.st_ctime = stat->ctime.tv_sec;
 160         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 161 }
 162
 163 asmlinkage long sys_stat(char __user * filename, struct __old_kernel_stat __user * statbuf)
 164 {
 165         struct kstat stat;
 166         int error = vfs_stat_fd(AT_FDCWD, filename, &stat);
 167
 168         if (!error)
 169                 error = cp_old_stat(&stat, statbuf);
 170
 171         return error;
 172 }
 173 asmlinkage long sys_lstat(char __user * filename, struct __old_kernel_stat __user * statbuf)
 174 {
 175         struct kstat stat;
 176         int error = vfs_lstat_fd(AT_FDCWD, filename, &stat);
 177
 178         if (!error)
 179                 error = cp_old_stat(&stat, statbuf);
 180
 181         return error;
 182 }
 183 asmlinkage long sys_fstat(unsigned int fd, struct __old_kernel_stat __user * statbuf)
 184 {
 185         struct kstat stat;
 186         int error = vfs_fstat(fd, &stat);
 187
 188         if (!error)
 189                 error = cp_old_stat(&stat, statbuf);
 190
 191         return error;
 192 }
 193
 194 #endif /* __ARCH_WANT_OLD_STAT */
 195
 196 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 197 {
 198         struct stat tmp;
 199
 200 #if BITS_PER_LONG == 32
 201         if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
 202                 return -EOVERFLOW;
 203 #else
 204         if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
 205                 return -EOVERFLOW;
 206 #endif
 207
 208         memset(&tmp, 0, sizeof(tmp));
 209 #if BITS_PER_LONG == 32
 210         tmp.st_dev = old_encode_dev(stat->dev);
 211 #else
 212         tmp.st_dev = new_encode_dev(stat->dev);
 213 #endif
 214         tmp.st_ino = stat->ino;
 215         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 216                 return -EOVERFLOW;
 217         tmp.st_mode = stat->mode;
 218         tmp.st_nlink = stat->nlink;
 219         if (tmp.st_nlink != stat->nlink)
 220                 return -EOVERFLOW;
 221         SET_UID(tmp.st_uid, stat->uid);
 222         SET_GID(tmp.st_gid, stat->gid);
 223 #if BITS_PER_LONG == 32
 224         tmp.st_rdev = old_encode_dev(stat->rdev);
 225 #else
 226         tmp.st_rdev = new_encode_dev(stat->rdev);
 227 #endif
 228 #if BITS_PER_LONG == 32
 229         if (stat->size > MAX_NON_LFS)
 230                 return -EOVERFLOW;
 231 #endif
 232         tmp.st_size = stat->size;
 233         tmp.st_atime = stat->atime.tv_sec;
 234         tmp.st_mtime = stat->mtime.tv_sec;
 235         tmp.st_ctime = stat->ctime.tv_sec;
 236 #ifdef STAT_HAVE_NSEC
 237         tmp.st_atime_nsec = stat->atime.tv_nsec;
 238         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 239         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 240 #endif
 241         tmp.st_blocks = stat->blocks;
 242         tmp.st_blksize = stat->blksize;
 243         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 244 }
 245
 246 asmlinkage long sys_newstat(char __user *filename, struct stat __user *statbuf)
 247 {
 248         struct kstat stat;
 249         int error = vfs_stat_fd(AT_FDCWD, filename, &stat);
 250
 251         if (!error)
 252                 error = cp_new_stat(&stat, statbuf);
 253
 254         return error;
 255 }
 256
 257 asmlinkage long sys_newlstat(char __user *filename, struct stat __user *statbuf)
 258 {
 259         struct kstat stat;
 260         int error = vfs_lstat_fd(AT_FDCWD, filename, &stat);
 261
 262         if (!error)
 263                 error = cp_new_stat(&stat, statbuf);
 264
 265         return error;
 266 }
 267
 268 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
 269 asmlinkage long sys_newfstatat(int dfd, char __user *filename,
 270                                 struct stat __user *statbuf, int flag)
 271 {
 272         struct kstat stat;
 273         int error = -EINVAL;
 274
 275         if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
 276                 goto out;
 277
 278         if (flag & AT_SYMLINK_NOFOLLOW)
 279                 error = vfs_lstat_fd(dfd, filename, &stat);
 280         else
 281                 error = vfs_stat_fd(dfd, filename, &stat);
 282
 283         if (!error)
 284                 error = cp_new_stat(&stat, statbuf);
 285
 286 out:
 287         return error;
 288 }
 289 #endif
 290
 291 asmlinkage long sys_newfstat(unsigned int fd, struct stat __user *statbuf)
 292 {
 293         struct kstat stat;
 294         int error = vfs_fstat(fd, &stat);
 295
 296         if (!error)
 297                 error = cp_new_stat(&stat, statbuf);
 298
 299         return error;
 300 }
 301
 302 asmlinkage long sys_readlinkat(int dfd, const char __user *path,
 303                                 char __user *buf, int bufsiz)
 304 {
 305         struct nameidata nd;
 306         int error;
 307
 308         if (bufsiz <= 0)
 309                 return -EINVAL;
 310
 311         error = __user_walk_fd(dfd, path, 0, &nd);
 312         if (!error) {
 313                 struct inode * inode = nd.dentry->d_inode;
 314
 315                 error = -EINVAL;
 316                 if (inode->i_op && inode->i_op->readlink) {
 317                         error = security_inode_readlink(nd.dentry);
 318                         if (!error) {
 319                                 touch_atime(nd.mnt, nd.dentry);
 320                                 error = inode->i_op->readlink(nd.dentry, buf, bufsiz);
 321                         }
 322                 }
 323                 path_release(&nd);
 324         }
 325         return error;
 326 }
 327
 328 asmlinkage long sys_readlink(const char __user *path, char __user *buf,
 329                                 int bufsiz)
 330 {
 331         return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
 332 }
 333
 334
 335 /* ---------- LFS-64 ----------- */
 336 #ifdef __ARCH_WANT_STAT64
 337
 338 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
 339 {
 340         struct stat64 tmp;
 341
 342         memset(&tmp, 0, sizeof(struct stat64));
 343 #ifdef CONFIG_MIPS
 344         /* mips has weird padding, so we don't get 64 bits there */
 345         if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
 346                 return -EOVERFLOW;
 347         tmp.st_dev = new_encode_dev(stat->dev);
 348         tmp.st_rdev = new_encode_dev(stat->rdev);
 349 #else
 350         tmp.st_dev = huge_encode_dev(stat->dev);
 351         tmp.st_rdev = huge_encode_dev(stat->rdev);
 352 #endif
 353         tmp.st_ino = stat->ino;
 354         if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
 355                 return -EOVERFLOW;
 356 #ifdef STAT64_HAS_BROKEN_ST_INO
 357         tmp.__st_ino = stat->ino;
 358 #endif
 359         tmp.st_mode = stat->mode;
 360         tmp.st_nlink = stat->nlink;
 361         tmp.st_uid = stat->uid;
 362         tmp.st_gid = stat->gid;
 363         tmp.st_atime = stat->atime.tv_sec;
 364         tmp.st_atime_nsec = stat->atime.tv_nsec;
 365         tmp.st_mtime = stat->mtime.tv_sec;
 366         tmp.st_mtime_nsec = stat->mtime.tv_nsec;
 367         tmp.st_ctime = stat->ctime.tv_sec;
 368         tmp.st_ctime_nsec = stat->ctime.tv_nsec;
 369         tmp.st_size = stat->size;
 370         tmp.st_blocks = stat->blocks;
 371         tmp.st_blksize = stat->blksize;
 372         return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
 373 }
 374
 375 asmlinkage long sys_stat64(char __user * filename, struct stat64 __user * statbuf)
 376 {
 377         struct kstat stat;
 378         int error = vfs_stat(filename, &stat);
 379
 380         if (!error)
 381                 error = cp_new_stat64(&stat, statbuf);
 382
 383         return error;
 384 }
 385 asmlinkage long sys_lstat64(char __user * filename, struct stat64 __user * statbuf)
 386 {
 387         struct kstat stat;
 388         int error = vfs_lstat(filename, &stat);
 389
 390         if (!error)
 391                 error = cp_new_stat64(&stat, statbuf);
 392
 393         return error;
 394 }
 395 asmlinkage long sys_fstat64(unsigned long fd, struct stat64 __user * statbuf)
 396 {
 397         struct kstat stat;
 398         int error = vfs_fstat(fd, &stat);
 399
 400         if (!error)
 401                 error = cp_new_stat64(&stat, statbuf);
 402
 403         return error;
 404 }
 405
 406 asmlinkage long sys_fstatat64(int dfd, char __user *filename,
 407                                struct stat64 __user *statbuf, int flag)
 408 {
 409         struct kstat stat;
 410         int error = -EINVAL;
 411
 412         if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
 413                 goto out;
 414
 415         if (flag & AT_SYMLINK_NOFOLLOW)
 416                 error = vfs_lstat_fd(dfd, filename, &stat);
 417         else
 418                 error = vfs_stat_fd(dfd, filename, &stat);
 419
 420         if (!error)
 421                 error = cp_new_stat64(&stat, statbuf);
 422
 423 out:
 424         return error;
 425 }
 426 #endif /* __ARCH_WANT_STAT64 */
 427
 428 void inode_add_bytes(struct inode *inode, loff_t bytes)
 429 {
 430         spin_lock(&inode->i_lock);
 431         inode->i_blocks += bytes >> 9;
 432         bytes &= 511;
 433         inode->i_bytes += bytes;
 434         if (inode->i_bytes >= 512) {
 435                 inode->i_blocks++;
 436                 inode->i_bytes -= 512;
 437         }
 438         spin_unlock(&inode->i_lock);
 439 }
 440
 441 EXPORT_SYMBOL(inode_add_bytes);
 442
 443 void inode_sub_bytes(struct inode *inode, loff_t bytes)
 444 {
 445         spin_lock(&inode->i_lock);
 446         inode->i_blocks -= bytes >> 9;
 447         bytes &= 511;
 448         if (inode->i_bytes < bytes) {
 449                 inode->i_blocks--;
 450                 inode->i_bytes += 512;
 451         }
 452         inode->i_bytes -= bytes;
 453         spin_unlock(&inode->i_lock);
 454 }
 455
 456 EXPORT_SYMBOL(inode_sub_bytes);
 457
 458 loff_t inode_get_bytes(struct inode *inode)
 459 {
 460         loff_t ret;
 461
 462         spin_lock(&inode->i_lock);
 463         ret = (((loff_t)inode->i_blocks) << 9) + inode->i_bytes;
 464         spin_unlock(&inode->i_lock);
 465         return ret;
 466 }
 467
 468 EXPORT_SYMBOL(inode_get_bytes);
 469
 470 void inode_set_bytes(struct inode *inode, loff_t bytes)
 471 {
 472         /* Caller is here responsible for sufficient locking
 473          * (ie. inode->i_lock) */
 474         inode->i_blocks = bytes >> 9;
 475         inode->i_bytes = bytes & 511;
 476 }
 477
 478 EXPORT_SYMBOL(inode_set_bytes);