FreeBSD/Linux Kernel Cross Reference
sys/ufs/ufs/dir.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * 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.
     *
     * 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.h       8.2 (Berkeley) 1/21/94
     * $FreeBSD$
     */
    
    #ifndef _UFS_UFS_DIR_H_
    #define _UFS_UFS_DIR_H_
    
    /*
     * Theoretically, directories can be more than 2Gb in length, however, in
     * practice this seems unlikely. So, we define the type doff_t as a 32-bit
     * quantity to keep down the cost of doing lookup on a 32-bit machine.
     */
    #define doff_t          int32_t
    #define MAXDIRSIZE      (0x7fffffff)
    
    /*
     * 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 UFS_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 UFS_MAXNAMLEN   255
    
    struct  direct {
            u_int32_t d_ino;                /* inode 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 */
            char      d_name[UFS_MAXNAMLEN + 1];
                                            /* name with length <= UFS_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
    #define DT_WHT          14
   
   /*
    * 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.
    */
   #define DIR_ROUNDUP     4       /* Directory name roundup size */
   #define DIRECTSIZ(namlen) \
       (roundup2(__offsetof(struct direct, d_name) + (namlen) + 1, DIR_ROUNDUP))
   #if (BYTE_ORDER == LITTLE_ENDIAN)
   #define DIRSIZ(oldfmt, dp) \
       ((oldfmt) ? DIRECTSIZ((dp)->d_type) : DIRECTSIZ((dp)->d_namlen))
   #else
   #define DIRSIZ(oldfmt, dp) \
       DIRECTSIZ((dp)->d_namlen)
   #endif
   #define OLDDIRFMT       1
   #define NEWDIRFMT       0
   
   /*
    * Template for manipulating directories.  Should use struct direct's,
    * but the name field is UFS_MAXNAMLEN - 1, and this just won't do.
    */
   struct dirtemplate {
           u_int32_t       dot_ino;
           int16_t         dot_reclen;
           u_int8_t        dot_type;
           u_int8_t        dot_namlen;
           char            dot_name[4];    /* must be multiple of 4 */
           u_int32_t       dotdot_ino;
           int16_t         dotdot_reclen;
           u_int8_t        dotdot_type;
           u_int8_t        dotdot_namlen;
           char            dotdot_name[4]; /* ditto */
   };
   
   /*
    * This is the old format of directories, sanz type element.
    */
   struct odirtemplate {
           u_int32_t       dot_ino;
           int16_t         dot_reclen;
           u_int16_t       dot_namlen;
           char            dot_name[4];    /* must be multiple of 4 */
           u_int32_t       dotdot_ino;
           int16_t         dotdot_reclen;
           u_int16_t       dotdot_namlen;
           char            dotdot_name[4]; /* ditto */
   };
   #endif /* !_DIR_H_ */

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