usr/src/lib/libast/common/dir/opendir.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * opendir, closedir
  25  *
  26  * open|close directory stream
  27  *
  28  * POSIX compatible directory stream access routines:
  29  *
  30  *      #include <sys/types.h>
  31  *      #include <dirent.h>
  32  *
  33  * NOTE: readdir() returns a pointer to struct dirent
  34  */
  35
  36 #include "dirlib.h"
  37
  38 #if _dir_ok
  39
  40 NoN(opendir)
  41
  42 #else
  43
  44 static const char id_dir[] = "\n@(#)$Id: directory (AT&T Research) 1993-04-01 $\0\n";
  45
  46 static DIR*     freedirp;               /* always keep one dirp */
  47
  48 DIR*
  49 opendir(register const char* path)
  50 {
  51         register DIR*   dirp = 0;
  52         register int    fd;
  53         struct stat     st;
  54
  55         if ((fd = open(path, O_RDONLY)) < 0) return(0);
  56         if (fstat(fd, &st) < 0 ||
  57            !S_ISDIR(st.st_mode) && (errno = ENOTDIR) ||
  58            fcntl(fd, F_SETFD, FD_CLOEXEC) ||
  59            !(dirp = freedirp ? freedirp :
  60 #if defined(_DIR_PRIVATE_) || _ptr_dd_buf
  61            newof(0, DIR, 1, DIRBLKSIZ)
  62 #else
  63            newof(0, DIR, 1, 0)
  64 #endif
  65                 ))
  66         {
  67                 close(fd);
  68                 if (dirp)
  69                 {
  70                         if (!freedirp) freedirp = dirp;
  71                         else free(dirp);
  72                 }
  73                 return(0);
  74         }
  75         freedirp = 0;
  76         dirp->dd_fd = fd;
  77         dirp->dd_loc = dirp->dd_size = 0;       /* refill needed */
  78 #if defined(_DIR_PRIVATE_) || _ptr_dd_buf
  79         dirp->dd_buf = (void*)((char*)dirp + sizeof(DIR));
  80 #endif
  81         return(dirp);
  82 }
  83
  84 void
  85 closedir(register DIR* dirp)
  86 {
  87         if (dirp)
  88         {
  89                 close(dirp->dd_fd);
  90                 if (!freedirp) freedirp = dirp;
  91                 else free(dirp);
  92         }
  93 }
  94
  95 #endif