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.path.mnt, nd.path.dentry, stat);
  66                 path_put(&nd.path);
  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.path.mnt, nd.path.dentry, stat);
  86                 path_put(&nd.path);
  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.path.dentry->d_inode;
 306
 307                 error = -EINVAL;
 308                 if (inode->i_op && inode->i_op->readlink) {
 309                         error = security_inode_readlink(nd.path.dentry);
 310                         if (!error) {
 311                                 touch_atime(nd.path.mnt, nd.path.dentry);
 312                                 error = inode->i_op->readlink(nd.path.dentry,
 313                                                               buf, bufsiz);
 314                         }
 315                 }
 316                 path_put(&nd.path);
 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);