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 8.5 (Berkeley) 04/27/95 13 */ 14 15 #ifndef _DIR_H_ 16 #define _DIR_H_ 17 18 /* 19 * Theoretically, directories can be more than 2Gb in length, however, in 20 * practice this seems unlikely. So, we define the type doff_t as a 32-bit 21 * quantity to keep down the cost of doing lookup on a 32-bit machine. 22 */ 23 #define doff_t int32_t 24 #define MAXDIRSIZE (0x7fffffff) 25 26 /* 27 * A directory consists of some number of blocks of DIRBLKSIZ 28 * bytes, where DIRBLKSIZ is chosen such that it can be transferred 29 * to disk in a single atomic operation (e.g. 512 bytes on most machines). 30 * 31 * Each DIRBLKSIZ byte block contains some number of directory entry 32 * structures, which are of variable length. Each directory entry has 33 * a struct direct at the front of it, containing its inode number, 34 * the length of the entry, and the length of the name contained in 35 * the entry. These are followed by the name padded to a 4 byte boundary 36 * with null bytes. All names are guaranteed null terminated. 37 * The maximum length of a name in a directory is MAXNAMLEN. 38 * 39 * The macro DIRSIZ(fmt, dp) gives the amount of space required to represent 40 * a directory entry. Free space in a directory is represented by 41 * entries which have dp->d_reclen > DIRSIZ(fmt, dp). All DIRBLKSIZ bytes 42 * in a directory block are claimed by the directory entries. This 43 * usually results in the last entry in a directory having a large 44 * dp->d_reclen. When entries are deleted from a directory, the 45 * space is returned to the previous entry in the same directory 46 * block by increasing its dp->d_reclen. If the first entry of 47 * a directory block is free, then its dp->d_ino is set to 0. 48 * Entries other than the first in a directory do not normally have 49 * dp->d_ino set to 0. 50 */ 51 #define DIRBLKSIZ DEV_BSIZE 52 #define MAXNAMLEN 255 53 54 struct direct { 55 u_int32_t d_ino; /* inode number of entry */ 56 u_int16_t d_reclen; /* length of this record */ 57 u_int8_t d_type; /* file type, see below */ 58 u_int8_t d_namlen; /* length of string in d_name */ 59 char d_name[MAXNAMLEN + 1];/* name with length <= MAXNAMLEN */ 60 }; 61 62 /* 63 * File types 64 */ 65 #define DT_UNKNOWN 0 66 #define DT_FIFO 1 67 #define DT_CHR 2 68 #define DT_DIR 4 69 #define DT_BLK 6 70 #define DT_REG 8 71 #define DT_LNK 10 72 #define DT_SOCK 12 73 #define DT_WHT 14 74 75 /* 76 * Convert between stat structure types and directory types. 77 */ 78 #define IFTODT(mode) (((mode) & 0170000) >> 12) 79 #define DTTOIF(dirtype) ((dirtype) << 12) 80 81 /* 82 * The DIRSIZ macro gives the minimum record length which will hold 83 * the directory entry. This requires the amount of space in struct direct 84 * without the d_name field, plus enough space for the name with a terminating 85 * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary. 86 */ 87 #if (BYTE_ORDER == LITTLE_ENDIAN) 88 #define DIRSIZ(oldfmt, dp) \ 89 ((oldfmt) ? \ 90 ((sizeof(struct direct) - (MAXNAMLEN+1)) + (((dp)->d_type+1 + 3) &~ 3)) : \ 91 ((sizeof(struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))) 92 #else 93 #define DIRSIZ(oldfmt, dp) \ 94 ((sizeof(struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3)) 95 #endif 96 #define OLDDIRFMT 1 97 #define NEWDIRFMT 0 98 99 /* 100 * Template for manipulating directories. Should use struct direct's, 101 * but the name field is MAXNAMLEN - 1, and this just won't do. 102 */ 103 struct dirtemplate { 104 u_int32_t dot_ino; 105 int16_t dot_reclen; 106 u_int8_t dot_type; 107 u_int8_t dot_namlen; 108 char dot_name[4]; /* must be multiple of 4 */ 109 u_int32_t dotdot_ino; 110 int16_t dotdot_reclen; 111 u_int8_t dotdot_type; 112 u_int8_t dotdot_namlen; 113 char dotdot_name[4]; /* ditto */ 114 }; 115 116 /* 117 * This is the old format of directories, sanz type element. 118 */ 119 struct odirtemplate { 120 u_int32_t dot_ino; 121 int16_t dot_reclen; 122 u_int16_t dot_namlen; 123 char dot_name[4]; /* must be multiple of 4 */ 124 u_int32_t dotdot_ino; 125 int16_t dotdot_reclen; 126 u_int16_t dotdot_namlen; 127 char dotdot_name[4]; /* ditto */ 128 }; 129 #endif /* !_DIR_H_ */ 130