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         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);