1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * %sccs.include.redist.c% 11 * 12 * @(#)dir.h 8.3 (Berkeley) 07/08/94 13 */ 14 15 #ifndef _DIR_H_ 16 #define _DIR_H_ 17 18 /* 19 * A directory consists of some number of blocks of DIRBLKSIZ 20 * bytes, where DIRBLKSIZ is chosen such that it can be transferred 21 * to disk in a single atomic operation (e.g. 512 bytes on most machines). 22 * 23 * Each DIRBLKSIZ byte block contains some number of directory entry 24 * structures, which are of variable length. Each directory entry has 25 * a struct direct at the front of it, containing its inode number, 26 * the length of the entry, and the length of the name contained in 27 * the entry. These are followed by the name padded to a 4 byte boundary 28 * with null bytes. All names are guaranteed null terminated. 29 * The maximum length of a name in a directory is MAXNAMLEN. 30 * 31 * The macro DIRSIZ(fmt, dp) gives the amount of space required to represent 32 * a directory entry. Free space in a directory is represented by 33 * entries which have dp->d_reclen > DIRSIZ(fmt, dp). All DIRBLKSIZ bytes 34 * in a directory block are claimed by the directory entries. This 35 * usually results in the last entry in a directory having a large 36 * dp->d_reclen. When entries are deleted from a directory, the 37 * space is returned to the previous entry in the same directory 38 * block by increasing its dp->d_reclen. If the first entry of 39 * a directory block is free, then its dp->d_ino is set to 0. 40 * Entries other than the first in a directory do not normally have 41 * dp->d_ino set to 0. 42 */ 43 #define DIRBLKSIZ DEV_BSIZE 44 #define MAXNAMLEN 255 45 46 struct direct { 47 u_int32_t d_ino; /* inode number of entry */ 48 u_int16_t d_reclen; /* length of this record */ 49 u_int8_t d_type; /* file type, see below */ 50 u_int8_t d_namlen; /* length of string in d_name */ 51 char d_name[MAXNAMLEN + 1];/* name with length <= MAXNAMLEN */ 52 }; 53 54 /* 55 * File types 56 */ 57 #define DT_UNKNOWN 0 58 #define DT_FIFO 1 59 #define DT_CHR 2 60 #define DT_DIR 4 61 #define DT_BLK 6 62 #define DT_REG 8 63 #define DT_LNK 10 64 #define DT_SOCK 12 65 66 /* 67 * Convert between stat structure types and directory types. 68 */ 69 #define IFTODT(mode) (((mode) & 0170000) >> 12) 70 #define DTTOIF(dirtype) ((dirtype) << 12) 71 72 /* 73 * The DIRSIZ macro gives the minimum record length which will hold 74 * the directory entry. This requires the amount of space in struct direct 75 * without the d_name field, plus enough space for the name with a terminating 76 * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary. 77 */ 78 #if (BYTE_ORDER == LITTLE_ENDIAN) 79 #define DIRSIZ(oldfmt, dp) \ 80 ((oldfmt) ? \ 81 ((sizeof(struct direct) - (MAXNAMLEN+1)) + (((dp)->d_type+1 + 3) &~ 3)) : \ 82 ((sizeof(struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))) 83 #else 84 #define DIRSIZ(oldfmt, dp) \ 85 ((sizeof(struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3)) 86 #endif 87 #define OLDDIRFMT 1 88 #define NEWDIRFMT 0 89 90 /* 91 * Template for manipulating directories. Should use struct direct's, 92 * but the name field is MAXNAMLEN - 1, and this just won't do. 93 */ 94 struct dirtemplate { 95 u_int32_t dot_ino; 96 int16_t dot_reclen; 97 u_int8_t dot_type; 98 u_int8_t dot_namlen; 99 char dot_name[4]; /* must be multiple of 4 */ 100 u_int32_t dotdot_ino; 101 int16_t dotdot_reclen; 102 u_int8_t dotdot_type; 103 u_int8_t dotdot_namlen; 104 char dotdot_name[4]; /* ditto */ 105 }; 106 107 /* 108 * This is the old format of directories, sanz type element. 109 */ 110 struct odirtemplate { 111 u_int32_t dot_ino; 112 int16_t dot_reclen; 113 u_int16_t dot_namlen; 114 char dot_name[4]; /* must be multiple of 4 */ 115 u_int32_t dotdot_ino; 116 int16_t dotdot_reclen; 117 u_int16_t dotdot_namlen; 118 char dotdot_name[4]; /* ditto */ 119 }; 120 #endif /* !_DIR_H_ */ 121