include/dirent.h

   1 /*      dirent.h - Declarations for directory reading routines.
   2  *                                                      Author: Kees J. Bot
   3  *                                                              24 Apr 1989
   4  *
   5  * Note: The V7 format directory entries used under Minix must be transformed
   6  * into a struct dirent with a d_name of at least 15 characters.  Given that
   7  * we have to transform V7 entries anyhow it is little trouble to let the
   8  * routines understand the so-called "flex" directory format too.
   9  */
  10
  11 #ifndef _DIRENT_H
  12 #define _DIRENT_H
  13
  14 #ifndef _TYPES_H
  15 #include <sys/types.h>
  16 #endif
  17
  18 #include <sys/dir.h>
  19
  20 /* _fl_direct is a flexible directory entry.  Actually it's a union of 8
  21  * characters and the 3 fields defined below.
  22  */
  23
  24 /* Flexible directory entry: */
  25 struct _fl_direct {             /* First slot in an entry */
  26         ino_t           d_ino;
  27         unsigned char   d_extent;
  28         char            d_name[3];  /* two characters for the shortest name */
  29 };
  30
  31         /* Name of length len needs _EXTENT(len) extra slots. */
  32 #define _EXTENT(len)    (((len) + 5) >> 3)
  33
  34 /* Version 7 directory entry: */
  35 struct _v7_direct {
  36         ino_t           d_ino;
  37         char            d_name[DIRSIZ];
  38 };
  39
  40 /* The block size must be at least 1024 bytes, because otherwise
  41  * the superblock (at 1024 bytes) overlaps with other filesystem data.
  42  */
  43 #define _MIN_BLOCK_SIZE          1024
  44
  45 /* The below is allocated in some parts of the system as the largest
  46  * a filesystem block can be. For instance, the boot monitor allocates
  47  * 3 of these blocks and has to fit within 64kB, so this can't be
  48  * increased without taking that into account.
  49  */
  50 #define _MAX_BLOCK_SIZE          4096
  51
  52 /* This is the block size for the fixed versions of the filesystem (V1/V2) */
  53 #define _STATIC_BLOCK_SIZE      1024
  54
  55 #define _STATIC_FLEX_PER_BLOCK (_STATIC_BLOCK_SIZE/sizeof(struct _fl_direct))
  56 #define _FLEX_PER_V7 (_EXTENT(DIRSIZ) + 1)
  57 #define _FLEX_PER_BLOCK (_STATIC_BLOCK_SIZE/sizeof(struct _fl_direct))
  58
  59 /* Definitions for the directory(3) routines: */
  60 typedef struct {
  61         char            _fd;    /* Filedescriptor of open directory */
  62         unsigned        _count; /* This many bytes in _buf */
  63         unsigned        _pos;   /* Position in _buf */
  64         char             _buf[_MAX_BLOCK_SIZE]; /* The size does not really
  65                                                  * matter as long as the
  66                                                  * buffer is big enough
  67                                                  * to contain at least one
  68                                                  * entry.
  69                                                  */
  70 } DIR;
  71
  72 #define _DIRENT_NAME_LEN 61
  73
  74 struct dirent {         /* Largest entry (8 slots) */
  75         ino_t           d_ino;          /* I-node number */
  76         off_t           d_off;          /* Offset in directory */
  77         unsigned short  d_reclen;       /* Length of this record */
  78         char            d_name[1];      /* Null terminated name */
  79 };
  80
  81 /* Function Prototypes. */
  82 _PROTOTYPE( int closedir, (DIR *_dirp)                                  );
  83 _PROTOTYPE( DIR *opendir, (const char *_dirname)                        );
  84 _PROTOTYPE( struct dirent *readdir, (DIR *_dirp)                        );
  85 _PROTOTYPE( void rewinddir, (DIR *_dirp)                                );
  86
  87 #ifdef _MINIX
  88 _PROTOTYPE( int seekdir, (DIR *_dirp, off_t _loc)                       );
  89 _PROTOTYPE( off_t telldir, (DIR *_dirp)                                 );
  90
  91 #define   dirfd(dirp)     ((dirp)->_fd)
  92
  93 _PROTOTYPE( int getdents, (int _fildes, struct dirent *_buf,
  94                                                         size_t _nbyte)  );
  95
  96 #endif
  97
  98 #endif /* _DIRENT_H */