* Copyright (c) 1982, 1986, 1989 The Regents of the University of California.
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
* @(#)dir.h 7.6 (Berkeley) %G%
* A directory consists of some number of blocks of DIRBLKSIZ
* bytes, where DIRBLKSIZ is chosen such that it can be transferred
* to disk in a single atomic operation (e.g. 512 bytes on most machines).
* Each DIRBLKSIZ byte block contains some number of directory entry
* structures, which are of variable length. Each directory entry has
* a struct direct at the front of it, containing its inode number,
* the length of the entry, and the length of the name contained in
* the entry. These are followed by the name padded to a 4 byte boundary
* with null bytes. All names are guaranteed null terminated.
* The maximum length of a name in a directory is MAXNAMLEN.
* The macro DIRSIZ(dp) gives the amount of space required to represent
* a directory entry. Free space in a directory is represented by
* entries which have dp->d_reclen > DIRSIZ(dp). All DIRBLKSIZ bytes
* in a directory block are claimed by the directory entries. This
* usually results in the last entry in a directory having a large
* dp->d_reclen. When entries are deleted from a directory, the
* space is returned to the previous entry in the same directory
* block by increasing its dp->d_reclen. If the first entry of
* a directory block is free, then its dp->d_ino is set to 0.
* Entries other than the first in a directory do not normally have
#define DIRBLKSIZ DEV_BSIZE
u_long d_ino
; /* inode number of entry */
u_short d_reclen
; /* length of this record */
u_short d_namlen
; /* length of string in d_name */
char d_name
[MAXNAMLEN
+ 1]; /* name with length <= MAXNAMLEN */
* The DIRSIZ macro gives the minimum record length which will hold
* the directory entry. This requires the amount of space in struct direct
* without the d_name field, plus enough space for the name with a terminating
* null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))
* Template for manipulating directories.
* Should use struct direct's, but the name field
* is MAXNAMLEN - 1, and this just won't do.
char dot_name
[4]; /* must be multiple of 4 */
char dotdot_name
[4]; /* ditto */
* The following information should be obtained from <dirent.h>
* and is provided solely (and temporarily) for backward compatibility.
#define d_fileno d_ino /* compatibility with POSIX */
* Definitions for library routines operating on directories.
typedef struct _dirdesc
{
#define dirfd(dirp) ((dirp)->dd_fd)
extern struct direct
*readdir();
#define rewinddir(dirp) seekdir((dirp), (long)0)