BSD 4_3_Reno release

[unix-history] / usr / src / share / man / man5 / dir.5

diff --git a/usr/src/share/man/man5/dir.5 b/usr/src/share/man/man5/dir.5
index 2a64243..b762522 100644 (file)
--- a/usr/src/share/man/man5/dir.5
+++ b/usr/src/share/man/man5/dir.5
@@ -1,7 +1,11 @@
-.\"    @(#)dir.5       4.1 (Berkeley) %G%
+.\" Copyright (c) 1983 Regents of the University of California.
+.\" All rights reserved.  The Berkeley software License Agreement
+.\" specifies the terms and conditions for redistribution.

 .\"
 .\"

-.TH DIR 5 
-.AT 3
+.\"    @(#)dir.5       6.1 (Berkeley) 5/15/85
+.\"
+.TH DIR 5  "May 15, 1985"
+.UC 5

 .SH NAME
 dir \- format of directories
 .SH SYNOPSIS
 .SH NAME
 dir \- format of directories
 .SH SYNOPSIS


@@ -9,38 +13,81 @@ dir \- format of directories
 .br
 .B #include <sys/dir.h>
 .SH DESCRIPTION
 .br
 .B #include <sys/dir.h>
 .SH DESCRIPTION

-A directory
-behaves exactly like an ordinary file, save that no
+A directory behaves exactly like an ordinary file, save that no

 user may write into a directory.
 The fact that a file is a directory is indicated by
 user may write into a directory.
 The fact that a file is a directory is indicated by

-a bit in the flag word of its i-node entry;
-see
-.IR filsys (5).
-The structure of a directory entry as given in the
-include file is:
+a bit in the flag word of its i-node entry; see
+.IR fs (5).
+The structure of a directory entry as given in the include file is:

 .RS
 .RS

-.ta 8n +10n
+.ta 8n +10n +10n

 .PP
 .nf
 .PP
 .nf

-#ifndef        DIRSIZ
-#define        DIRSIZ  14
+/*
+ * 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
+ * dp->d_ino set to 0.
+ */
+#ifdef KERNEL
+#define DIRBLKSIZ DEV_BSIZE
+#else
+#define        DIRBLKSIZ 512

 #endif
 #endif

-struct direct
-{
-       ino_t   d_ino;
-       char    d_name[DIRSIZ];
+
+#define MAXNAMLEN 255
+
+/*
+ * 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.
+ */
+#undef DIRSIZ
+#define DIRSIZ(dp) \e
+    ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))
+
+struct direct {
+       u_long  d_ino;
+       short   d_reclen;
+       short   d_namlen;
+       char    d_name[MAXNAMLEN + 1];
+       /* typically shorter */
+};
+
+struct _dirdesc {
+       int     dd_fd;
+       long    dd_loc;
+       long    dd_size;
+       char    dd_buf[DIRBLKSIZ];

 };
 .fi
 .RE
 .PP
 By convention, the first two entries in each directory
 };
 .fi
 .RE
 .PP
 By convention, the first two entries in each directory

-are for `\fB.\fR' and `\fB..\fR'.  The first is an entry for the
-directory itself.  The second is for the parent
-directory.
-The meaning of `\fB..\fR' is modified for the root directory
-of the master file system
-.RB (\*(lq / \*(rq),
-where `\fB..\fR' has the
-same meaning as `\fB.\fR'.
+are for `.' and `..'.  The first is an entry for the
+directory itself.  The second is for the parent directory.
+The meaning of `..' is modified for the root directory
+of the master file system (\*(lq/\*(rq),
+where `..' has the same meaning as `.'.

 .SH "SEE ALSO"
 .SH "SEE ALSO"

-filsys(5)
+fs(5)