bsd/man/man5/dir.5

   1 .\"     $NetBSD: dir.5,v 1.5 1995/03/28 17:30:20 jtc Exp $
   2 .\"
   3 .\" Copyright (c) 1983, 1991, 1993
   4 .\"     The Regents of the University of California.  All rights reserved.
   5 .\"
   6 .\" Redistribution and use in source and binary forms, with or without
   7 .\" modification, are permitted provided that the following conditions
   8 .\" are met:
   9 .\" 1. Redistributions of source code must retain the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer.
  11 .\" 2. Redistributions in binary form must reproduce the above copyright
  12 .\"    notice, this list of conditions and the following disclaimer in the
  13 .\"    documentation and/or other materials provided with the distribution.
  14 .\" 3. All advertising materials mentioning features or use of this software
  15 .\"    must display the following acknowledgement:
  16 .\"     This product includes software developed by the University of
  17 .\"     California, Berkeley and its contributors.
  18 .\" 4. Neither the name of the University nor the names of its contributors
  19 .\"    may be used to endorse or promote products derived from this software
  20 .\"    without specific prior written permission.
  21 .\"
  22 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32 .\" SUCH DAMAGE.
  33 .\"
  34 .\"     @(#)dir.5       8.3 (Berkeley) 4/19/94
  35 .\"
  36 .Dd April 19, 1994
  37 .Dt DIR 5
  38 .Os BSD 4.2
  39 .Sh NAME
  40 .Nm dir ,
  41 .Nm dirent
  42 .Nd directory file format
  43 .Sh SYNOPSIS
  44 .Fd #include <sys/types.h>
  45 .Fd #include <sys/dir.h>
  46 .Sh DESCRIPTION
  47 Directories provide a convenient hierarchical method of grouping
  48 files while obscuring the underlying details of the storage medium.
  49 A directory file is differentiated from a plain file
  50 by a flag in its
  51 .Xr inode 5
  52 entry.
  53 It consists of records (directory entries) each of which contains
  54 information about a file and a pointer to the file itself.
  55 Directory entries may contain other directories
  56 as well as plain files; such nested directories are refered to as
  57 subdirectories.
  58 A hierarchy of directories and files is formed in this manner
  59 and is called a file system (or referred to as a file system tree).
  60 .\" An entry in this tree,
  61 .\" nested or not nested,
  62 .\" is a pathname.
  63 .Pp
  64 Each directory file contains two special directory entries; one is a pointer
  65 to the directory itself
  66 called dot
  67 .Ql \&.
  68 and the other a pointer to its parent directory called dot-dot
  69 .Ql \&.. .
  70 Dot and dot-dot
  71 are valid pathnames, however,
  72 the system root directory
  73 .Ql / ,
  74 has no parent and dot-dot points to itself like dot.
  75 .Pp
  76 File system nodes are ordinary directory files on which has
  77 been grafted a file system object, such as a physical disk or a
  78 partitioned area of such a disk.
  79 (See
  80 .Xr mount 1
  81 and
  82 .Xr mount 8 . )
  83 .Pp
  84 The directory entry format is defined in the file
  85 .Aq sys/dirent.h
  86 and further in the file
  87 .Aq dirent.h :
  88 .Bd -literal
  89 /*** Excerpt from <sys/dirent.h> ***/
  90 /*
  91  * The dirent structure defines the format of directory entries.
  92  *
  93  * A directory entry has a struct dirent at the front of it, containing its
  94  * inode number, the length of the entry, and the length of the name
  95  * contained in the entry.  These are followed by the name padded to a 4
  96  * byte boundary with null bytes.  All names are guaranteed null terminated.
  97  * The maximum length of a name in a directory is MAXPATHLEN.
  98  */
  99
 100 #ifndef _SYS_DIRENT_H
 101 #define _SYS_DIRENT_H
 102
 103 struct dirent {
 104         ino_t     d_ino;                /* file number of entry */
 105         u_int64_t d_seekoff;            /* length of this record */
 106         u_int16_t d_reclen;             /* length of this record */
 107         u_int16_t d_namlen;             /* length of string in d_name */
 108         u_int8_t  d_type;               /* file type, see below */
 109         char      d_name[MAXPATHLEN];   /* name must be no longer than this */
 110 };
 111
 112 /*
 113  * File types
 114  */
 115 #define DT_UNKNOWN       0
 116 #define DT_FIFO          1
 117 #define DT_CHR           2
 118 #define DT_DIR           4
 119 #define DT_BLK           6
 120 #define DT_REG           8
 121 #define DT_LNK          10
 122 #define DT_SOCK         12
 123 #define DT_WHT          14
 124
 125 #endif /* !_SYS_DIRENT_H_ */
 126
 127 .Ed
 128 -----------------------------------------
 129 .Bd -literal
 130 /*** Excerpt from <dirent.h> ***/
 131
 132 #ifndef _DIRENT_H
 133 #define _DIRENT_H
 134
 135 /* definitions for library routines operating on directories. */
 136 #define DIRBLKSIZ       1024
 137
 138 struct _telldir;                /* see telldir.h */
 139
 140 /* structure describing an open directory. */
 141 typedef struct {
 142         int     __dd_fd;        /* file descriptor associated with directory */
 143         long    __dd_loc;       /* offset in current buffer */
 144         long    __dd_size;      /* amount of data returned by getdirentries */
 145         char    *__dd_buf;      /* data buffer */
 146         int     __dd_len;       /* size of data buffer */
 147         long    __dd_seek;      /* magic cookie returned by getdirentries */
 148         long    __dd_rewind;    /* magic cookie for rewinding */
 149         int     __dd_flags;     /* flags for readdir */
 150         pthread_mutex_t __dd_lock; /* for thread locking */
 151         struct _telldir *__dd_td; /* telldir position recording */
 152 } DIR;
 153
 154 #define dirfd(dirp)     ((dirp)->__dd_fd)
 155
 156 /* flags for opendir2 */
 157 #define DTF_HIDEW       0x0001  /* hide whiteout entries */
 158 #define DTF_NODUP       0x0002  /* don't return duplicate names */
 159 #define DTF_REWIND      0x0004  /* rewind after reading union stack */
 160 #define __DTF_READALL   0x0008  /* everything has been read */
 161
 162 #endif /* !_DIRENT_H_ */
 163 .Ed
 164 .Sh SEE ALSO
 165 .Xr fs 5 ,
 166 .Xr inode 5
 167 .Sh HISTORY
 168 A
 169 .Nm
 170 file format appeared in
 171 .At v7 .