lib/readdir.c

   1 /* Read the next entry of a directory.
   2    Copyright (C) 2011-2018 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <dirent.h>
  21
  22 #include <errno.h>
  23 #include <stddef.h>
  24
  25 #include "dirent-private.h"
  26
  27 struct dirent *
  28 readdir (DIR *dirp)
  29 {
  30   char type;
  31   struct dirent *result;
  32
  33   /* There is no need to add code to produce entries for "." and "..".
  34      According to the POSIX:2008 section "4.12 Pathname Resolution"
  35      <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html>
  36      "." and ".." are syntactic entities.
  37      POSIX also says:
  38        "If entries for dot or dot-dot exist, one entry shall be returned
  39         for dot and one entry shall be returned for dot-dot; otherwise,
  40         they shall not be returned."  */
  41
  42   switch (dirp->status)
  43     {
  44     case -2:
  45       /* End of directory already reached.  */
  46       return NULL;
  47     case -1:
  48       break;
  49     case 0:
  50       if (!FindNextFile (dirp->current, &dirp->entry))
  51         {
  52           switch (GetLastError ())
  53             {
  54             case ERROR_NO_MORE_FILES:
  55               dirp->status = -2;
  56               return NULL;
  57             default:
  58               errno = EIO;
  59               return NULL;
  60             }
  61         }
  62       break;
  63     default:
  64       errno = dirp->status;
  65       return NULL;
  66     }
  67
  68   dirp->status = 0;
  69
  70   if (dirp->entry.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
  71     type = DT_DIR;
  72   else if (dirp->entry.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
  73     type = DT_LNK;
  74   else if ((dirp->entry.dwFileAttributes
  75             & ~(FILE_ATTRIBUTE_READONLY
  76                 | FILE_ATTRIBUTE_HIDDEN
  77                 | FILE_ATTRIBUTE_SYSTEM
  78                 | FILE_ATTRIBUTE_ARCHIVE
  79                 | FILE_ATTRIBUTE_NORMAL
  80                 | FILE_ATTRIBUTE_TEMPORARY
  81                 | FILE_ATTRIBUTE_SPARSE_FILE
  82                 | FILE_ATTRIBUTE_COMPRESSED
  83                 | FILE_ATTRIBUTE_NOT_CONTENT_INDEXED
  84                 | FILE_ATTRIBUTE_ENCRYPTED)) == 0)
  85     /* Devices like COM1, LPT1, NUL would also have the attributes 0x20 but
  86        they cannot occur here.  */
  87     type = DT_REG;
  88   else
  89     type = DT_UNKNOWN;
  90
  91   /* Reuse the memory of dirp->entry for the result.  */
  92   result =
  93     (struct dirent *)
  94     ((char *) dirp->entry.cFileName - offsetof (struct dirent, d_name[0]));
  95   result->d_type = type;
  96
  97   return result;
  98 }