gen/readdir.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1983, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55
  56 #include <sys/param.h>
  57 #include <dirent.h>
  58
  59 /*
  60  * get next entry in a directory.
  61  */
  62 struct dirent *
  63 readdir(dirp)
  64         register DIR *dirp;
  65 {
  66         register struct dirent *dp;
  67
  68         for (;;) {
  69                 if (dirp->dd_loc >= dirp->dd_size) {
  70                         if (dirp->dd_flags & __DTF_READALL)
  71                                 return (NULL);
  72                         dirp->dd_loc = 0;
  73                 }
  74                 if (dirp->dd_loc == 0 && !(dirp->dd_flags & __DTF_READALL)) {
  75                         dirp->dd_size = getdirentries(dirp->dd_fd,
  76                             dirp->dd_buf, dirp->dd_len, &dirp->dd_seek);
  77                         if (dirp->dd_size <= 0)
  78                                 return (NULL);
  79                 }
  80                 dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
  81                 if ((int)dp & 03)       /* bogus pointer check */
  82                         return (NULL);
  83                 if (dp->d_reclen <= 0 ||
  84                     dp->d_reclen > dirp->dd_len + 1 - dirp->dd_loc)
  85                         return (NULL);
  86                 dirp->dd_loc += dp->d_reclen;
  87                 if (dp->d_ino == 0)
  88                         continue;
  89                 if (dp->d_type == DT_WHT && (dirp->dd_flags & DTF_HIDEW))
  90                         continue;
  91                 return (dp);
  92         }
  93 }