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UDIR.H
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1991-02-22
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/* @(#)udir.h 1.1 86/06/30 UNFSSRC */
/*
* Copyright (c) 1986 Sun Microsystems, Inc.
*/
/*
* A directory consists of some number of blocks each of which is
* less than or equal to the filesystem block size number of
* bytes.
*
* Each 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 file 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 MAXNAMLEN, plus
* a null byte.
*
* The macro DIRSIZ(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(dp).
*
* All the 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. Free entries have their dp->d_fileno set to 0.
*/
#define MAXNAMLEN 255
struct direct {
u_long d_fileno; /* file number of entry */
u_short d_reclen; /* length of this record */
u_short d_namlen; /* length of string in d_name */
char d_name[MAXNAMLEN + 1]; /* name (up to MAXNAMLEN + 1) */
};
/*
* user-level nfs cookie includes offset field.
*/
struct udirect {
u_long d_fileno; /* file number of entry */
u_short d_reclen; /* length of this record */
u_short d_namlen; /* length of string d_name */
u_long d_offset; /* offset into the directory */
char d_name[MAXNAMLEN + 1]; /* name (up to MAXNAMLEN + 1) */
};
/*
* 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.
*/
#undef DIRSIZ
#define DIRSIZ(dp) \
((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))
#define UDIRSIZ(dp) \
((sizeof (struct udirect) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))
/*
* Definitions for library routines operating on directories.
*/
typedef struct _dirdesc {
int dd_fd;
long dd_loc;
long dd_size;
long dd_bbase;
long dd_entno;
long dd_bsize;
char *dd_buf;
} DIR;
#ifndef NULL
#define NULL 0
#endif
extern DIR *opendir();
extern struct direct *readdir();
extern long telldir();
extern void seekdir();
#define rewinddir(dirp) seekdir((dirp), (long)0)
extern void closedir();