1 /* 2 * Copyright (c) 1982, 1986, 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 * 7 * @(#)dir.h 8.1 (Berkeley) 06/11/93 8 */ 9 10 #ifndef _DIR_H_ 11 #define _DIR_H_ 12 13 /* 14 * A directory consists of some number of blocks of DIRBLKSIZ 15 * bytes, where DIRBLKSIZ is chosen such that it can be transferred 16 * to disk in a single atomic operation (e.g. 512 bytes on most machines). 17 * 18 * Each DIRBLKSIZ byte block contains some number of directory entry 19 * structures, which are of variable length. Each directory entry has 20 * a struct direct at the front of it, containing its inode number, 21 * the length of the entry, and the length of the name contained in 22 * the entry. These are followed by the name padded to a 4 byte boundary 23 * with null bytes. All names are guaranteed null terminated. 24 * The maximum length of a name in a directory is MAXNAMLEN. 25 * 26 * The macro DIRSIZ(fmt, dp) gives the amount of space required to represent 27 * a directory entry. Free space in a directory is represented by 28 * entries which have dp->d_reclen > DIRSIZ(fmt, dp). All DIRBLKSIZ bytes 29 * in a directory block are claimed by the directory entries. This 30 * usually results in the last entry in a directory having a large 31 * dp->d_reclen. When entries are deleted from a directory, the 32 * space is returned to the previous entry in the same directory 33 * block by increasing its dp->d_reclen. If the first entry of 34 * a directory block is free, then its dp->d_ino is set to 0. 35 * Entries other than the first in a directory do not normally have 36 * dp->d_ino set to 0. 37 */ 38 #define DIRBLKSIZ DEV_BSIZE 39 #define MAXNAMLEN 255 40 41 struct direct { 42 u_long d_ino; /* inode number of entry */ 43 u_short d_reclen; /* length of this record */ 44 u_char d_type; /* file type, see below */ 45 u_char d_namlen; /* length of string in d_name */ 46 char d_name[MAXNAMLEN + 1]; /* name with length <= MAXNAMLEN */ 47 }; 48 49 /* 50 * File types 51 */ 52 #define DT_UNKNOWN 0 53 #define DT_FIFO 1 54 #define DT_CHR 2 55 #define DT_DIR 4 56 #define DT_BLK 6 57 #define DT_REG 8 58 #define DT_LNK 10 59 #define DT_SOCK 12 60 61 /* 62 * Convert between stat structure types and directory types. 63 */ 64 #define IFTODT(mode) (((mode) & 0170000) >> 12) 65 #define DTTOIF(dirtype) ((dirtype) << 12) 66 67 /* 68 * The DIRSIZ macro gives the minimum record length which will hold 69 * the directory entry. This requires the amount of space in struct direct 70 * without the d_name field, plus enough space for the name with a terminating 71 * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary. 72 */ 73 #if (BYTE_ORDER == LITTLE_ENDIAN) 74 #define DIRSIZ(oldfmt, dp) \ 75 ((oldfmt) ? \ 76 ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_type+1 + 3) &~ 3)) : \ 77 ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))) 78 #else 79 #define DIRSIZ(oldfmt, dp) \ 80 ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3)) 81 #endif 82 #define OLDDIRFMT 1 83 #define NEWDIRFMT 0 84 85 /* 86 * Template for manipulating directories. 87 * Should use struct direct's, but the name field 88 * is MAXNAMLEN - 1, and this just won't do. 89 */ 90 struct dirtemplate { 91 u_long dot_ino; 92 short dot_reclen; 93 u_char dot_type; 94 u_char dot_namlen; 95 char dot_name[4]; /* must be multiple of 4 */ 96 u_long dotdot_ino; 97 short dotdot_reclen; 98 u_char dotdot_type; 99 u_char dotdot_namlen; 100 char dotdot_name[4]; /* ditto */ 101 }; 102 103 /* 104 * This is the old format of directories, sanz type element. 105 */ 106 struct odirtemplate { 107 u_long dot_ino; 108 short dot_reclen; 109 u_short dot_namlen; 110 char dot_name[4]; /* must be multiple of 4 */ 111 u_long dotdot_ino; 112 short dotdot_reclen; 113 u_short dotdot_namlen; 114 char dotdot_name[4]; /* ditto */ 115 }; 116 #endif /* !_DIR_H_ */ 117