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
  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);