/* $NetBSD: dir.h,v 1.25.10.1 2020/03/02 08:07:22 martin Exp $ */ /* * 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 8.5 (Berkeley) 4/27/95 */ #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 UFS_MAXDIRSIZE (0x7fffffff) /* * A directory consists of some number of blocks of UFS_DIRBLKSIZ * bytes, where UFS_DIRBLKSIZ is chosen such that it can be transferred * to disk in a single atomic operation (e.g. 512 bytes on most machines). * * Each UFS_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. * All names are guaranteed null terminated. * The maximum length of a name in a directory is FFS_MAXNAMLEN. * * The macro UFS_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 UFS_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. */ #undef UFS_DIRBLKSIZ #define UFS_DIRBLKSIZ DEV_BSIZE #define FFS_MAXNAMLEN 255 #define APPLEUFS_DIRBLKSIZ 1024 #define d_ino d_fileno struct direct { u_int32_t d_fileno; /* 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[FFS_MAXNAMLEN + 1];/* name with length <= FFS_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 UFS_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 #define UFS_NAMEROUNDUP(namlen) (((namlen) + DIR_ROUNDUP) & ~(DIR_ROUNDUP - 1)) #define UFS_NAMEPAD(namlen) (DIR_ROUNDUP - ((namlen) & (DIR_ROUNDUP - 1))) #define UFS_DIRECTSIZ(namlen) \ ((sizeof(struct direct) - (FFS_MAXNAMLEN+1)) + UFS_NAMEROUNDUP(namlen)) #if (BYTE_ORDER == LITTLE_ENDIAN) #define UFS_DIRSIZ(oldfmt, dp, needswap) \ (((oldfmt) && !(needswap)) ? \ UFS_DIRECTSIZ((dp)->d_type) : UFS_DIRECTSIZ((dp)->d_namlen)) #else #define UFS_DIRSIZ(oldfmt, dp, needswap) \ (((oldfmt) && (needswap)) ? \ UFS_DIRECTSIZ((dp)->d_type) : UFS_DIRECTSIZ((dp)->d_namlen)) #endif /* * UFS_OLDDIRFMT and UFS_NEWDIRFMT are code numbers for a directory * format change that happened in ffs a long time ago. (Back in the * 80s, if I'm not mistaken.) * * These code numbers do not appear on disk. They're generated from * runtime logic that is cued by other things, which is why * UFS_OLDDIRFMT is confusingly 1 and UFS_NEWDIRFMT is confusingly 0. * * Relatedly, the FFS_EI byte swapping logic for directories is a * horrible mess. For example, to access the namlen field, one * currently does the following: * * #if (BYTE_ORDER == LITTLE_ENDIAN) * swap = (UFS_IPNEEDSWAP(VTOI(vp)) == 0); * #else * swap = (UFS_IPNEEDSWAP(VTOI(vp)) != 0); * #endif * return ((FSFMT(vp) && swap) ? dp->d_type : dp->d_namlen); * * UFS_IPNEEDSWAP() returns true if the volume is opposite-endian. This * horrible "swap" logic is cutpasted all over everywhere but amounts * to the following: * * running code volume lfs_dobyteswap "swap" * ---------------------------------------------------------- * LITTLE_ENDIAN LITTLE_ENDIAN false true * LITTLE_ENDIAN BIG_ENDIAN true false * BIG_ENDIAN LITTLE_ENDIAN true true * BIG_ENDIAN BIG_ENDIAN false false * * which you'll note boils down to "volume is little-endian". * * Meanwhile, FSFMT(vp) yields UFS_OLDDIRFMT or UFS_NEWDIRFMT via * perverted logic of its own. Since UFS_OLDDIRFMT is 1 (contrary to * what one might expect approaching this cold) what this mess means * is: on OLDDIRFMT volumes that are little-endian, we read the * namlen value out of the type field. This is because on OLDDIRFMT * volumes there is no d_type field, just a 16-bit d_namlen; so if * the 16-bit d_namlen is little-endian, the useful part of it is * in the first byte, which in the NEWDIRFMT structure is the d_type * field. */ #define UFS_OLDDIRFMT 1 #define UFS_NEWDIRFMT 0 /* * Template for manipulating directories. Should use struct direct's, * but the name field is FFS_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, sans 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 /* !_UFS_UFS_DIR_H_ */