122 lines
4.1 KiB
Groff
122 lines
4.1 KiB
Groff
.\" $NetBSD: dir.5,v 1.17 2003/08/07 10:31:16 agc Exp $
|
|
.\"
|
|
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)dir.5 8.3 (Berkeley) 4/19/94
|
|
.\"
|
|
.Dd August 12, 2002
|
|
.Dt DIRENT 5
|
|
.Os
|
|
.Sh NAME
|
|
.Nm dirent
|
|
.Nd directory format
|
|
.Sh SYNOPSIS
|
|
.In sys/types.h
|
|
.In sys/dirent.h
|
|
.Sh DESCRIPTION
|
|
Directories provide a convenient hierarchical method of grouping
|
|
files while obscuring the underlying details of the storage medium.
|
|
A directory file is differentiated from a plain file
|
|
by a flag in its
|
|
.Xr inode 5
|
|
entry.
|
|
It consists of records (directory entries) each of which contains
|
|
information about a file and a pointer to the file itself.
|
|
Directory entries may contain other directories
|
|
as well as plain files; such nested directories are referred to as
|
|
subdirectories.
|
|
A hierarchy of directories and files is formed in this manner
|
|
and is called a file system (or referred to as a file system tree).
|
|
.\" An entry in this tree,
|
|
.\" nested or not nested,
|
|
.\" is a pathname.
|
|
.Pp
|
|
Each directory file contains two special directory entries; one is a pointer
|
|
to the directory itself
|
|
called dot
|
|
.Ql \&.
|
|
and the other a pointer to its parent directory called dot-dot
|
|
.Ql \&.. .
|
|
Dot and dot-dot
|
|
are valid pathnames, however,
|
|
the system root directory
|
|
.Ql / ,
|
|
has no parent and dot-dot points to itself like dot.
|
|
.Pp
|
|
File system nodes are ordinary directory files on which has
|
|
been grafted a file system object, such as a physical disk or a
|
|
partitioned area of such a disk.
|
|
(See
|
|
.Xr mount 8 . )
|
|
.Pp
|
|
The directory entry format is defined in the file
|
|
.Aq Pa sys/dirent.h :
|
|
.Bd -literal
|
|
/*
|
|
* A directory entry has a struct dirent 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.
|
|
*/
|
|
|
|
struct dirent {
|
|
u_int32_t d_fileno; /* file number of entry */
|
|
u_int16_t d_reclen; /* length of this record */
|
|
u_int8_t d_type; /* file type, see below */
|
|
u_int8_t d_namlen; /* length of string in d_name */
|
|
#define MAXNAMLEN 255
|
|
char d_name[MAXNAMLEN + 1]; /* name must be no longer than this */
|
|
};
|
|
|
|
/*
|
|
* File types
|
|
*/
|
|
#define DT_UNKNOWN 0
|
|
#define DT_FIFO 1
|
|
#define DT_CHR 2
|
|
#define DT_DIR 4
|
|
#define DT_BLK 6
|
|
#define DT_REG 8
|
|
#define DT_LNK 10
|
|
#define DT_SOCK 12
|
|
#define DT_WHT 14
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr getdents 2 ,
|
|
.Xr fs 5 ,
|
|
.Xr inode 5
|
|
.Sh HISTORY
|
|
A
|
|
dir structure appeared in
|
|
.At v7 .
|
|
The
|
|
.Nm
|
|
structure appeared in
|
|
.Nx 1.3 .
|