[unix-history] / usr / src / sys / ufs / ufs / dir.h

/*
* Copyright (c) 1982, 1986, 1989, 1993
*      The Regents of the University of California.  All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* %sccs.include.redist.c%
*
*      @(#)dir.h       8.2 (Berkeley) %G%
*/

#ifndef _DIR_H_
#define _DIR_H_

/*
* 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(fmt, 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(fmt, 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.
*/
#define DIRBLKSIZ       DEV_BSIZE
#define MAXNAMLEN       255

struct  direct {
       u_long  d_ino;                  /* inode number of entry */
       u_short d_reclen;               /* length of this record */
       u_char  d_type;                 /* file type, see below */
       u_char  d_namlen;               /* length of string in d_name */
       char    d_name[MAXNAMLEN + 1];  /* name with length <= MAXNAMLEN */
};

/*
* 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

/*
* Convert between stat structure types and directory types.
*/
#define IFTODT(mode)    (((mode) & 0170000) >> 12)
#define DTTOIF(dirtype) ((dirtype) << 12)

/*
* 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.
*/
#if (BYTE_ORDER == LITTLE_ENDIAN)
#define DIRSIZ(oldfmt, dp) \
   ((oldfmt) ? \
   ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_type+1 + 3) &~ 3)) : \
   ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3)))
#else
#define DIRSIZ(oldfmt, dp) \
   ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))
#endif
#define OLDDIRFMT       1
#define NEWDIRFMT       0

/*
* Template for manipulating directories.
* Should use struct direct's, but the name field
* is MAXNAMLEN - 1, and this just won't do.
*/
struct dirtemplate {
       u_long  dot_ino;
       short   dot_reclen;
       u_char  dot_type;
       u_char  dot_namlen;
       char    dot_name[4];            /* must be multiple of 4 */
       u_long  dotdot_ino;
       short   dotdot_reclen;
       u_char  dotdot_type;
       u_char  dotdot_namlen;
       char    dotdot_name[4];         /* ditto */
};

/*
* This is the old format of directories, sanz type element.
*/
struct odirtemplate {
       u_long  dot_ino;
       short   dot_reclen;
       u_short dot_namlen;
       char    dot_name[4];            /* must be multiple of 4 */
       u_long  dotdot_ino;
       short   dotdot_reclen;
       u_short dotdot_namlen;
       char    dotdot_name[4];         /* ditto */
};
#endif /* !_DIR_H_ */