lib/opendir.c

   1 /* Start reading the entries of a directory.
   2    Copyright (C) 2006-2024 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 HAVE_OPENDIR
  26
  27 /* Override opendir(), to keep track of the open file descriptors.
  28    Needed because there is a function dirfd().  */
  29
  30 #else
  31
  32 # include "filename.h"
  33
  34 #endif
  35
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #if GNULIB_defined_DIR
  40 # include "dirent-private.h"
  41 #endif
  42
  43 #if REPLACE_FCHDIR
  44 # include <unistd.h>
  45 #endif
  46
  47 #if defined _WIN32 && ! defined __CYGWIN__
  48 /* Don't assume that UNICODE is not defined.  */
  49 # undef WIN32_FIND_DATA
  50 # define WIN32_FIND_DATA WIN32_FIND_DATAA
  51 # undef GetFullPathName
  52 # define GetFullPathName GetFullPathNameA
  53 # undef FindFirstFile
  54 # define FindFirstFile FindFirstFileA
  55 #endif
  56
  57 DIR *
  58 opendir (const char *dir_name)
  59 #undef opendir
  60 {
  61 #if HAVE_DIRENT_H                       /* equivalent to HAVE_OPENDIR */
  62   DIR *dirp;
  63
  64 # if GNULIB_defined_DIR
  65 #  undef DIR
  66
  67   dirp = (struct gl_directory *) malloc (sizeof (struct gl_directory));
  68   if (dirp == NULL)
  69     {
  70       errno = ENOMEM;
  71       return NULL;
  72     }
  73
  74   DIR *real_dirp = opendir (dir_name);
  75   if (real_dirp == NULL)
  76     {
  77       int saved_errno = errno;
  78       free (dirp);
  79       errno = saved_errno;
  80       return NULL;
  81     }
  82
  83   dirp->fd_to_close = -1;
  84   dirp->real_dirp = real_dirp;
  85 # else
  86   dirp = opendir (dir_name);
  87   if (dirp == NULL)
  88     return NULL;
  89 # endif
  90
  91 #else
  92
  93   char dir_name_mask[MAX_PATH + 1 + 1 + 1];
  94   int status;
  95   HANDLE current;
  96   WIN32_FIND_DATA entry;
  97   struct gl_directory *dirp;
  98
  99   if (dir_name[0] == '\0')
 100     {
 101       errno = ENOENT;
 102       return NULL;
 103     }
 104
 105   /* Make the dir_name absolute, so that we continue reading the same
 106      directory if the current directory changed between this opendir()
 107      call and a subsequent rewinddir() call.  */
 108   if (!GetFullPathName (dir_name, MAX_PATH, dir_name_mask, NULL))
 109     {
 110       errno = EINVAL;
 111       return NULL;
 112     }
 113
 114   /* Append the mask.
 115      "*" and "*.*" appear to be equivalent.  */
 116   {
 117     char *p;
 118
 119     p = dir_name_mask + strlen (dir_name_mask);
 120     if (p > dir_name_mask && !ISSLASH (p[-1]))
 121       *p++ = '\\';
 122     *p++ = '*';
 123     *p = '\0';
 124   }
 125
 126   /* Start searching the directory.  */
 127   status = -1;
 128   current = FindFirstFile (dir_name_mask, &entry);
 129   if (current == INVALID_HANDLE_VALUE)
 130     {
 131       switch (GetLastError ())
 132         {
 133         case ERROR_FILE_NOT_FOUND:
 134           status = -2;
 135           break;
 136         case ERROR_PATH_NOT_FOUND:
 137           errno = ENOENT;
 138           return NULL;
 139         case ERROR_DIRECTORY:
 140           errno = ENOTDIR;
 141           return NULL;
 142         case ERROR_ACCESS_DENIED:
 143           errno = EACCES;
 144           return NULL;
 145         default:
 146           errno = EIO;
 147           return NULL;
 148         }
 149     }
 150
 151   /* Allocate the result.  */
 152   dirp =
 153     (struct gl_directory *)
 154     malloc (offsetof (struct gl_directory, dir_name_mask[0])
 155             + strlen (dir_name_mask) + 1);
 156   if (dirp == NULL)
 157     {
 158       if (current != INVALID_HANDLE_VALUE)
 159         FindClose (current);
 160       errno = ENOMEM;
 161       return NULL;
 162     }
 163   dirp->fd_to_close = -1;
 164   dirp->status = status;
 165   dirp->current = current;
 166   if (status == -1)
 167     memcpy (&dirp->entry, &entry, sizeof (WIN32_FIND_DATA));
 168   strcpy (dirp->dir_name_mask, dir_name_mask);
 169
 170 #endif
 171
 172 #if REPLACE_FCHDIR
 173   {
 174     int fd = dirfd (dirp);
 175     if (0 <= fd && _gl_register_fd (fd, dir_name) != fd)
 176       {
 177         int saved_errno = errno;
 178         closedir (dirp);
 179         errno = saved_errno;
 180         return NULL;
 181       }
 182   }
 183 #endif
 184
 185   return dirp;
 186 }