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/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);