lib/readdir.c

   1 /* Read the next entry of a directory.
   2    Copyright (C) 2011-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file 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 Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser 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 #if GNULIB_defined_DIR
  26 # include "dirent-private.h"
  27 #endif
  28
  29 /* Don't assume that UNICODE is not defined.  */
  30 #undef FindNextFile
  31 #define FindNextFile FindNextFileA
  32
  33 struct dirent *
  34 readdir (DIR *dirp)
  35 #undef readdir
  36 {
  37 #if HAVE_DIRENT_H                       /* equivalent to HAVE_READDIR */
  38   return readdir (dirp->real_dirp);
  39 #else
  40   char type;
  41   struct dirent *result;
  42
  43   /* There is no need to add code to produce entries for "." and "..".
  44      According to the POSIX:2008 section "4.12 Pathname Resolution"
  45      <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html>
  46      "." and ".." are syntactic entities.
  47      POSIX also says:
  48        "If entries for dot or dot-dot exist, one entry shall be returned
  49         for dot and one entry shall be returned for dot-dot; otherwise,
  50         they shall not be returned."  */
  51
  52   switch (dirp->status)
  53     {
  54     case -2:
  55       /* End of directory already reached.  */
  56       return NULL;
  57     case -1:
  58       break;
  59     case 0:
  60       if (!FindNextFile (dirp->current, &dirp->entry))
  61         {
  62           switch (GetLastError ())
  63             {
  64             case ERROR_NO_MORE_FILES:
  65               dirp->status = -2;
  66               return NULL;
  67             default:
  68               errno = EIO;
  69               return NULL;
  70             }
  71         }
  72       break;
  73     default:
  74       errno = dirp->status;
  75       return NULL;
  76     }
  77
  78   dirp->status = 0;
  79
  80   if (dirp->entry.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
  81     type = DT_DIR;
  82   else if (dirp->entry.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
  83     type = DT_LNK;
  84   else if ((dirp->entry.dwFileAttributes
  85             & ~(FILE_ATTRIBUTE_READONLY
  86                 | FILE_ATTRIBUTE_HIDDEN
  87                 | FILE_ATTRIBUTE_SYSTEM
  88                 | FILE_ATTRIBUTE_ARCHIVE
  89                 | FILE_ATTRIBUTE_NORMAL
  90                 | FILE_ATTRIBUTE_TEMPORARY
  91                 | FILE_ATTRIBUTE_SPARSE_FILE
  92                 | FILE_ATTRIBUTE_COMPRESSED
  93                 | FILE_ATTRIBUTE_NOT_CONTENT_INDEXED
  94                 | FILE_ATTRIBUTE_ENCRYPTED)) == 0)
  95     /* Devices like COM1, LPT1, NUL would also have the attributes 0x20 but
  96        they cannot occur here.  */
  97     type = DT_REG;
  98   else
  99     type = DT_UNKNOWN;
 100
 101   /* Reuse the memory of dirp->entry for the result.  */
 102   result =
 103     (struct dirent *)
 104     ((char *) dirp->entry.cFileName - offsetof (struct dirent, d_name[0]));
 105   result->d_type = type;
 106
 107   return result;
 108 #endif
 109 }