Merge branch 'w32-gfileinfo-improvements' into 'master'

W32 GFileInfo improvements

See merge request GNOME/glib!238

gio/gfileinfo-priv.h

@@ -85,6 +85,8 @@
 #define G_FILE_ATTRIBUTE_ID_UNIX_IS_MOUNTPOINT (7340032 + 10)
 #define G_FILE_ATTRIBUTE_ID_DOS_IS_ARCHIVE (8388608 + 1)
 #define G_FILE_ATTRIBUTE_ID_DOS_IS_SYSTEM (8388608 + 2)
+#define G_FILE_ATTRIBUTE_ID_DOS_IS_MOUNTPOINT (8388608 + 3)
+#define G_FILE_ATTRIBUTE_ID_DOS_REPARSE_POINT_TAG (8388608 + 4)
 #define G_FILE_ATTRIBUTE_ID_OWNER_USER (9437184 + 1)
 #define G_FILE_ATTRIBUTE_ID_OWNER_USER_REAL (9437184 + 2)
 #define G_FILE_ATTRIBUTE_ID_OWNER_GROUP (9437184 + 3)

gio/gfileinfo.c

@@ -245,6 +245,8 @@ ensure_attribute_hash (void)
   REGISTER_ATTRIBUTE (UNIX_IS_MOUNTPOINT);
   REGISTER_ATTRIBUTE (DOS_IS_ARCHIVE);
   REGISTER_ATTRIBUTE (DOS_IS_SYSTEM);
+  REGISTER_ATTRIBUTE (DOS_IS_MOUNTPOINT);
+  REGISTER_ATTRIBUTE (DOS_REPARSE_POINT_TAG);
   REGISTER_ATTRIBUTE (OWNER_USER);
   REGISTER_ATTRIBUTE (OWNER_USER_REAL);
   REGISTER_ATTRIBUTE (OWNER_GROUP);

gio/gfileinfo.h

@@ -672,6 +672,33 @@ typedef struct _GFileInfoClass   GFileInfoClass;
  **/
 #define G_FILE_ATTRIBUTE_DOS_IS_SYSTEM "dos::is-system"           /* boolean */
 
+/**
+ * G_FILE_ATTRIBUTE_DOS_IS_MOUNTPOINT:
+ *
+ * A key in the "dos" namespace for checking if the file is a NTFS mount point
+ * (a volume mount or a junction point).
+ * This attribute is %TRUE if file is a reparse point of type
+ * [IO_REPARSE_TAG_MOUNT_POINT](https://msdn.microsoft.com/en-us/library/dd541667.aspx).
+ * This attribute is only available for DOS file systems.
+ * Corresponding #GFileAttributeType is %G_FILE_ATTRIBUTE_TYPE_BOOLEAN.
+ *
+ * Since: 2.60
+ **/
+#define G_FILE_ATTRIBUTE_DOS_IS_MOUNTPOINT "dos::is-mountpoint"   /* boolean */
+
+/**
+ * G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG:
+ *
+ * A key in the "dos" namespace for getting the file NTFS reparse tag.
+ * This value is 0 for files that are not reparse points.
+ * See the [Reparse Tags](https://msdn.microsoft.com/en-us/library/dd541667.aspx)
+ * page for possible reparse tag values. Corresponding #GFileAttributeType
+ * is %G_FILE_ATTRIBUTE_TYPE_UINT32.
+ *
+ * Since: 2.60
+ **/
+#define G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG "dos::reparse-point-tag"   /* uint32 */
+
 /* Owner attributes */
 
 /**

gio/glocalfileinfo.c

@@ -1867,6 +1867,12 @@ _g_local_file_info_get (const char             *basename,
 
   if (statbuf.attributes & FILE_ATTRIBUTE_SYSTEM)
     _g_file_info_set_attribute_boolean_by_id (info, G_FILE_ATTRIBUTE_ID_DOS_IS_SYSTEM, TRUE);
+
+  if (statbuf.reparse_tag == IO_REPARSE_TAG_MOUNT_POINT)
+    _g_file_info_set_attribute_boolean_by_id (info, G_FILE_ATTRIBUTE_ID_DOS_IS_MOUNTPOINT, TRUE);
+
+  if (statbuf.reparse_tag != 0)
+    _g_file_info_set_attribute_uint32_by_id (info, G_FILE_ATTRIBUTE_ID_DOS_REPARSE_POINT_TAG, statbuf.reparse_tag);
 #endif
 
   symlink_target = NULL;

gio/tests/g-file-info.c

@@ -180,16 +180,24 @@ test_internal_enhanced_stdio (void)
       gchar *programdata;
       gchar *users_dir;
       gchar *allusers;
-      GFile *gf_programdata, *gf_allusers;
+      gchar *commondata;
-      GFileInfo *fi_programdata, *fi_allusers, *fi_allusers_target;
+      GFile *gf_programdata, *gf_allusers, *gf_commondata;
+      GFileInfo *fi_programdata, *fi_allusers, *fi_allusers_target, *fi_commondata, *fi_commondata_target;
       GFileType ft_allusers;
       GFileType ft_allusers_target;
       GFileType ft_programdata;
+      GFileType ft_commondata;
       gboolean allusers_is_symlink;
+      gboolean commondata_is_symlink;
+      gboolean commondata_is_mount_point;
+      guint32 allusers_reparse_tag;
+      guint32 commondata_reparse_tag;
       const gchar *id_allusers;
       const gchar *id_allusers_target;
+      const gchar *id_commondata_target;
       const gchar *id_programdata;
       const gchar *allusers_target;
+      const gchar *commondata_target;
 
       /* C:/ProgramData */
       programdata = g_utf16_to_utf8 (programdata_dir_w, -1, NULL, NULL, NULL);
@@ -201,7 +209,11 @@ test_internal_enhanced_stdio (void)
        * for "C:/ProgramData".
        */
       allusers = g_build_filename (users_dir, "All Users", NULL);
-      g_assert_nonnull (allusers);
+
+      /* "C:/Users/All Users/Application Data" is a known
+       * junction for "C:/ProgramData"
+       */
+      commondata = g_build_filename (allusers, "Application Data", NULL);
 
       /* We don't test g_stat() and g_lstat() on these directories,
        * because it is pointless - there's no way to tell that these
@@ -213,6 +225,7 @@ test_internal_enhanced_stdio (void)
        */
       gf_programdata = g_file_new_for_path (programdata);
       gf_allusers = g_file_new_for_path (allusers);
+      gf_commondata = g_file_new_for_path (commondata);
 
       fi_programdata = g_file_query_info (gf_programdata,
                                           G_FILE_ATTRIBUTE_ID_FILE ","
@@ -229,52 +242,99 @@ test_internal_enhanced_stdio (void)
       fi_allusers = g_file_query_info (gf_allusers,
                                        G_FILE_ATTRIBUTE_STANDARD_SYMLINK_TARGET ","
                                        G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK ","
+                                       G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG ","
                                        G_FILE_ATTRIBUTE_ID_FILE ","
                                        G_FILE_ATTRIBUTE_STANDARD_TYPE,
                                        G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
                                        NULL, NULL);
 
-      g_assert (g_file_info_has_attribute (fi_programdata, G_FILE_ATTRIBUTE_ID_FILE));
+      fi_commondata = g_file_query_info (gf_commondata,
-      g_assert (g_file_info_has_attribute (fi_programdata, G_FILE_ATTRIBUTE_STANDARD_TYPE));
+                                         G_FILE_ATTRIBUTE_STANDARD_SYMLINK_TARGET ","
+                                         G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK ","
+                                         G_FILE_ATTRIBUTE_DOS_IS_MOUNTPOINT ","
+                                         G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG ","
+                                         G_FILE_ATTRIBUTE_ID_FILE ","
+                                         G_FILE_ATTRIBUTE_STANDARD_TYPE,
+                                         G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
+                                         NULL, NULL);
 
-      g_assert (g_file_info_has_attribute (fi_allusers_target, G_FILE_ATTRIBUTE_ID_FILE));
+      fi_commondata_target = g_file_query_info (gf_commondata,
-      g_assert (g_file_info_has_attribute (fi_allusers_target, G_FILE_ATTRIBUTE_STANDARD_TYPE));
+                                                G_FILE_ATTRIBUTE_ID_FILE ","
+                                                G_FILE_ATTRIBUTE_STANDARD_TYPE,
+                                                G_FILE_QUERY_INFO_NONE,
+                                                NULL, NULL);
 
-      g_assert (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_ID_FILE));
+      g_assert_true (g_file_info_has_attribute (fi_programdata, G_FILE_ATTRIBUTE_ID_FILE));
-      g_assert (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_STANDARD_TYPE));
+      g_assert_true (g_file_info_has_attribute (fi_programdata, G_FILE_ATTRIBUTE_STANDARD_TYPE));
-      g_assert (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK));
+
-      g_assert (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_STANDARD_SYMLINK_TARGET));
+      g_assert_true (g_file_info_has_attribute (fi_allusers_target, G_FILE_ATTRIBUTE_ID_FILE));
+      g_assert_true (g_file_info_has_attribute (fi_allusers_target, G_FILE_ATTRIBUTE_STANDARD_TYPE));
+      g_assert_true (g_file_info_has_attribute (fi_commondata_target, G_FILE_ATTRIBUTE_ID_FILE));
+      g_assert_true (g_file_info_has_attribute (fi_commondata_target, G_FILE_ATTRIBUTE_STANDARD_TYPE));
+
+      g_assert_true (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_ID_FILE));
+      g_assert_true (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_STANDARD_TYPE));
+      g_assert_true (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK));
+      g_assert_true (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG));
+      g_assert_true (g_file_info_has_attribute (fi_allusers, G_FILE_ATTRIBUTE_STANDARD_SYMLINK_TARGET));
+
+      g_assert_true (g_file_info_has_attribute (fi_commondata, G_FILE_ATTRIBUTE_ID_FILE));
+      g_assert_true (g_file_info_has_attribute (fi_commondata, G_FILE_ATTRIBUTE_STANDARD_TYPE));
+      g_assert_true (g_file_info_has_attribute (fi_commondata, G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK));
+      g_assert_true (g_file_info_has_attribute (fi_commondata, G_FILE_ATTRIBUTE_DOS_IS_MOUNTPOINT));
+      g_assert_true (g_file_info_has_attribute (fi_commondata, G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG));
+      g_assert_true (g_file_info_has_attribute (fi_commondata, G_FILE_ATTRIBUTE_STANDARD_SYMLINK_TARGET));
 
       ft_allusers = g_file_info_get_file_type (fi_allusers);
       ft_allusers_target = g_file_info_get_file_type (fi_allusers_target);
       ft_programdata = g_file_info_get_file_type (fi_programdata);
+      ft_commondata = g_file_info_get_file_type (fi_commondata);
 
-      g_assert (ft_allusers == G_FILE_TYPE_SYMBOLIC_LINK);
+      g_assert_cmpint (ft_allusers, ==, G_FILE_TYPE_SYMBOLIC_LINK);
-      g_assert (ft_allusers_target == G_FILE_TYPE_DIRECTORY);
+      g_assert_cmpint (ft_allusers_target, ==, G_FILE_TYPE_DIRECTORY);
-      g_assert (ft_programdata == G_FILE_TYPE_DIRECTORY);
+      g_assert_cmpint (ft_programdata, ==, G_FILE_TYPE_DIRECTORY);
+      g_assert_cmpint (ft_commondata, ==, G_FILE_TYPE_SYMBOLIC_LINK);
 
       allusers_is_symlink = g_file_info_get_attribute_boolean (fi_allusers, G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK);
+      allusers_reparse_tag = g_file_info_get_attribute_uint32 (fi_allusers, G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG);
+      commondata_is_symlink = g_file_info_get_attribute_boolean (fi_commondata, G_FILE_ATTRIBUTE_STANDARD_IS_SYMLINK);
+      commondata_is_mount_point = g_file_info_get_attribute_boolean (fi_commondata, G_FILE_ATTRIBUTE_DOS_IS_MOUNTPOINT);
+      commondata_reparse_tag = g_file_info_get_attribute_uint32 (fi_commondata, G_FILE_ATTRIBUTE_DOS_REPARSE_POINT_TAG);
 
       g_assert_true (allusers_is_symlink);
+      g_assert_cmpuint (allusers_reparse_tag, ==, IO_REPARSE_TAG_SYMLINK);
+      g_assert_true (commondata_is_symlink);
+      g_assert_true (commondata_is_mount_point);
+      g_assert_cmpuint (commondata_reparse_tag, ==, IO_REPARSE_TAG_MOUNT_POINT);
 
       id_allusers = g_file_info_get_attribute_string (fi_allusers, G_FILE_ATTRIBUTE_ID_FILE);
       id_allusers_target = g_file_info_get_attribute_string (fi_allusers_target, G_FILE_ATTRIBUTE_ID_FILE);
+      id_commondata_target = g_file_info_get_attribute_string (fi_commondata_target, G_FILE_ATTRIBUTE_ID_FILE);
       id_programdata = g_file_info_get_attribute_string (fi_programdata, G_FILE_ATTRIBUTE_ID_FILE);
 
       g_assert_cmpstr (id_allusers_target, ==, id_programdata);
+      g_assert_cmpstr (id_commondata_target, ==, id_programdata);
       g_assert_cmpstr (id_allusers, !=, id_programdata);
 
       allusers_target = g_file_info_get_symlink_target (fi_allusers);
 
       g_assert_true (g_str_has_suffix (allusers_target, "ProgramData"));
 
+      commondata_target = g_file_info_get_symlink_target (fi_commondata);
+
+      g_assert_true (g_str_has_suffix (commondata_target, "ProgramData"));
+
       g_object_unref (fi_allusers);
       g_object_unref (fi_allusers_target);
+      g_object_unref (fi_commondata);
+      g_object_unref (fi_commondata_target);
       g_object_unref (fi_programdata);
       g_object_unref (gf_allusers);
+      g_object_unref (gf_commondata);
       g_object_unref (gf_programdata);
 
       g_free (allusers);
+      g_free (commondata);
       g_free (users_dir);
       g_free (programdata);
     }
@@ -325,7 +385,7 @@ test_internal_enhanced_stdio (void)
       g_assert_nonnull (f);
 
       h = (HANDLE) _get_osfhandle (fileno (f));
-      g_assert (h != INVALID_HANDLE_VALUE);
+      g_assert_cmpuint ((guintptr) h, !=, (guintptr) INVALID_HANDLE_VALUE);
 
       ssb.SetSparse = TRUE;
       g_assert_true (DeviceIoControl (h,
@@ -364,8 +424,8 @@ test_internal_enhanced_stdio (void)
 
       g_remove (ps);
 
-      g_assert (g_file_info_has_attribute (fi_ps, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+      g_assert_true (g_file_info_has_attribute (fi_ps, G_FILE_ATTRIBUTE_STANDARD_SIZE));
-      g_assert (g_file_info_has_attribute (fi_ps, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE));
+      g_assert_true (g_file_info_has_attribute (fi_ps, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE));
 
       size_ps = g_file_info_get_attribute_uint64 (fi_ps, G_FILE_ATTRIBUTE_STANDARD_SIZE);
       alsize_ps = g_file_info_get_attribute_uint64 (fi_ps, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE);
@@ -404,7 +464,7 @@ test_internal_enhanced_stdio (void)
   g_assert_nonnull (f);
 
   h = (HANDLE) _get_osfhandle (fileno (f));
-  g_assert (h != INVALID_HANDLE_VALUE);
+  g_assert_cmpuint ((guintptr) h, !=, (guintptr) INVALID_HANDLE_VALUE);
 
   fprintf (f, "1");
   fflush (f);
@@ -443,15 +503,15 @@ test_internal_enhanced_stdio (void)
                              G_FILE_QUERY_INFO_NONE,
                              NULL, NULL);
 
-  g_assert (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+  g_assert_true (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_STANDARD_SIZE));
-  g_assert (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE));
+  g_assert_true (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE));
-  g_assert (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_ID_FILE));
+  g_assert_true (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_ID_FILE));
-  g_assert (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_TIME_MODIFIED));
+  g_assert_true (g_file_info_has_attribute (fi_p0, G_FILE_ATTRIBUTE_TIME_MODIFIED));
 
-  g_assert (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+  g_assert_true (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_STANDARD_SIZE));
-  g_assert (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE));
+  g_assert_true (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE));
-  g_assert (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_ID_FILE));
+  g_assert_true (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_ID_FILE));
-  g_assert (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_TIME_MODIFIED));
+  g_assert_true (g_file_info_has_attribute (fi_p1, G_FILE_ATTRIBUTE_TIME_MODIFIED));
 
   size_p0 = g_file_info_get_attribute_uint64 (fi_p0, G_FILE_ATTRIBUTE_STANDARD_SIZE);
   alsize_p0 = g_file_info_get_attribute_uint64 (fi_p0, G_FILE_ATTRIBUTE_STANDARD_ALLOCATED_SIZE);
@@ -469,7 +529,7 @@ test_internal_enhanced_stdio (void)
   /* st_ino from W32 stat() is useless for file identification.
    * It will be either 0, or it will be the same for both files.
    */
-  g_assert (statbuf_p0.st_ino == statbuf_p1.st_ino);
+  g_assert_cmpint (statbuf_p0.st_ino, ==, statbuf_p1.st_ino);
   g_assert_cmpstr (id_p0, !=, id_p1);
 
   time_p0 = g_file_info_get_attribute_uint64 (fi_p0, G_FILE_ATTRIBUTE_TIME_MODIFIED);
@@ -481,7 +541,7 @@ test_internal_enhanced_stdio (void)
    *  and 64-bit on 64-bit Windows, usually),
    * so it *can* pass this test in some cases.
    */
-  g_assert (time_p0 > G_GUINT64_CONSTANT (0xFFFFFFFF));
+  g_assert_cmpuint (time_p0, >, G_GUINT64_CONSTANT (0xFFFFFFFF));
 
   g_object_unref (fi_p0);
   g_object_unref (fi_p1);

glib/gstdio-private.c

@@ -0,0 +1,77 @@
+/* gstdio-private.c - private glib functions for gstdio.c
+ *
+ * Copyright 2004 Tor Lillqvist
+ * Copyright 2018 Руслан Ижбулатов
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Strips "\\\\?\\" extended prefix or
+ * "\\??\\" NT Object Manager prefix from
+ * @str in-place, using memmove.
+ * @str_size must point to the size of @str
+ * in gunichar2s, including NUL-terminator
+ * (if @str is NUL-terminated; it doesn't have to be).
+ * On return @str_size will correctly reflect changes
+ * in @str size (if any).
+ * Returns TRUE if @str was modified.
+ */
+static gboolean
+_g_win32_strip_extended_ntobjm_prefix (gunichar2 *str,
+                                       gsize     *str_size)
+{
+  const wchar_t *extended_prefix = L"\\\\?\\";
+  const gsize    extended_prefix_len = wcslen (extended_prefix);
+  const gsize    extended_prefix_len_bytes = sizeof (gunichar2) * extended_prefix_len;
+  const gsize    extended_prefix_with_drive_len_bytes = sizeof (gunichar2) * (extended_prefix_len + 2);
+  const wchar_t *ntobjm_prefix = L"\\??\\";
+  const gsize    ntobjm_prefix_len = wcslen (ntobjm_prefix);
+  const gsize    ntobjm_prefix_len_bytes = sizeof (gunichar2) * ntobjm_prefix_len;
+  const gsize    ntobjm_prefix_with_drive_len_bytes = sizeof (gunichar2) * (ntobjm_prefix_len + 2);
+  gboolean do_move = FALSE;
+  gsize move_shift = 0;
+
+  if ((*str_size) * sizeof (gunichar2) > extended_prefix_with_drive_len_bytes &&
+      memcmp (str,
+              extended_prefix,
+              extended_prefix_len_bytes) == 0 &&
+      iswascii (str[extended_prefix_len]) &&
+      iswalpha (str[extended_prefix_len]) &&
+      str[extended_prefix_len + 1] == L':')
+   {
+     do_move = TRUE;
+     move_shift = extended_prefix_len;
+   }
+  else if ((*str_size) * sizeof (gunichar2) > ntobjm_prefix_with_drive_len_bytes &&
+           memcmp (str,
+                   ntobjm_prefix,
+                   ntobjm_prefix_len_bytes) == 0 &&
+           iswascii (str[ntobjm_prefix_len]) &&
+           iswalpha (str[ntobjm_prefix_len]) &&
+           str[ntobjm_prefix_len + 1] == L':')
+    {
+      do_move = TRUE;
+      move_shift = ntobjm_prefix_len;
+    }
+
+  if (do_move)
+    {
+      *str_size -= move_shift;
+      memmove (str,
+               str + move_shift,
+               (*str_size) * sizeof (gunichar2));
+    }
+
+  return do_move;
+}

glib/gstdio.c

@@ -121,6 +121,8 @@ w32_error_to_errno (DWORD error_code)
     }
 }
 
+#include "gstdio-private.c"
+
 static int
 _g_win32_stat_utf16_no_trailing_slashes (const gunichar2    *filename,
                                          int                 fd,
@@ -259,15 +261,11 @@ _g_win32_stat_utf16_no_trailing_slashes (const gunichar2    *filename,
 
           if (new_len > 0)
             {
-              const wchar_t *extended_prefix = L"\\\\?\\";
-              const gsize    extended_prefix_len = wcslen (extended_prefix);
-              const gsize    extended_prefix_len_bytes = sizeof (wchar_t) * extended_prefix_len;
-
               /* Pretend that new_len doesn't count the terminating NUL char,
-               * and ask for a bit more space than is needed.
+               * and ask for a bit more space than is needed, and allocate even more.
                */
-              filename_target_len = new_len + 5;
+              filename_target_len = new_len + 3;
-              filename_target = g_malloc (filename_target_len * sizeof (wchar_t));
+              filename_target = g_malloc ((filename_target_len + 1) * sizeof (wchar_t));
 
               new_len = GetFinalPathNameByHandleW (file_handle,
                                                    filename_target,
@@ -284,17 +282,32 @@ _g_win32_stat_utf16_no_trailing_slashes (const gunichar2    *filename,
                   error_code = ERROR_BUFFER_OVERFLOW;
                   g_clear_pointer (&filename_target, g_free);
                 }
-              /* GetFinalPathNameByHandle() is documented to return extended paths,
+              else if (new_len == 0)
-               * strip the extended prefix.
-               */
-              else if (new_len > extended_prefix_len &&
-                       memcmp (filename_target, extended_prefix, extended_prefix_len_bytes) == 0)
                 {
-                  new_len -= extended_prefix_len;
+                  g_clear_pointer (&filename_target, g_free);
-                  memmove (filename_target,
-                           filename_target + extended_prefix_len,
-                           (new_len + 1) * sizeof (wchar_t));
                 }
+              /* GetFinalPathNameByHandle() is documented to return extended paths,
+               * strip the extended prefix, if it is followed by a drive letter
+               * and a colon. Otherwise keep it (the path could be
+               * \\\\?\\Volume{GUID}\\ - it's only usable in extended form).
+               */
+              else if (new_len > 0)
+                {
+                  gsize len = new_len;
+
+                  /* Account for NUL-terminator maybe not being counted.
+                   * This is why we overallocated earlier.
+                   */
+                  if (filename_target[len] != L'\0')
+                    {
+                      len++;
+                      filename_target[len] = L'\0';
+                    }
+
+                  _g_win32_strip_extended_ntobjm_prefix (filename_target, &len);
+                  new_len = len;
+                }
+
             }
 
           if (new_len == 0)
@@ -453,8 +466,9 @@ _g_win32_readlink_utf16_raw (const gunichar2 *filename,
    * point and use DeviceIoControl() on it.
    */
   h = CreateFileW (filename,
-                   FILE_READ_ATTRIBUTES | SYNCHRONIZE | GENERIC_READ,
+                   FILE_READ_EA,
-                   FILE_SHARE_READ, NULL, OPEN_EXISTING,
+                   FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
+                   NULL, OPEN_EXISTING,
                    FILE_ATTRIBUTE_NORMAL
                    | FILE_FLAG_OPEN_REPARSE_POINT
                    | (attributes & FILE_ATTRIBUTE_DIRECTORY ? FILE_FLAG_BACKUP_SEMANTICS : 0),
@@ -513,10 +527,8 @@ _g_win32_readlink_utf16 (const gunichar2 *filename,
                          gunichar2       *buf,
                          gsize            buf_size)
 {
-  const wchar_t *ntobjm_prefix = L"\\??\\";
+  int   result = _g_win32_readlink_utf16_raw (filename, buf, buf_size);
-  const gsize    ntobjm_prefix_len_unichar2 = wcslen (ntobjm_prefix);
+  gsize string_size;
-  const gsize    ntobjm_prefix_len_bytes = sizeof (gunichar2) * ntobjm_prefix_len_unichar2;
-  int            result = _g_win32_readlink_utf16_raw (filename, buf, buf_size);
 
   if (result <= 0)
     return result;
@@ -532,16 +544,16 @@ _g_win32_readlink_utf16 (const gunichar2 *filename,
   /* DeviceIoControl () tends to return filenames as NT Object Manager
    * names , i.e. "\\??\\C:\\foo\\bar".
    * Remove the leading 4-byte \??\ prefix, as glib (as well as many W32 API
-   * functions) is unprepared to deal with it.
+   * functions) is unprepared to deal with it. Unless it has no 'x:' drive
+   * letter part after the prefix, in which case we leave everything
+   * as-is, because the path could be "\??\Volume{GUID}" - stripping
+   * the prefix will allow it to be confused with relative links
+   * targeting "Volume{GUID}".
    */
-  if (result > ntobjm_prefix_len_bytes &&
+  string_size = result / sizeof (gunichar2);
-      memcmp (buf, ntobjm_prefix, ntobjm_prefix_len_bytes) == 0)
+  _g_win32_strip_extended_ntobjm_prefix (buf, &string_size);
-    {
-      result -= ntobjm_prefix_len_bytes;
-      memmove (buf, buf + ntobjm_prefix_len_unichar2, result);
-    }
 
-  return result;
+  return string_size * sizeof (gunichar2);
 }
 
 static gchar *

glib/tests/fileutils.c

@@ -1009,6 +1009,139 @@ test_fopen_modes (void)
   g_free (path);
 }
 
+#ifdef G_OS_WIN32
+#include "../gstdio-private.c"
+
+static int
+g_wcscmp0 (const gunichar2 *str1,
+           const gunichar2 *str2)
+{
+  if (!str1)
+    return -(str1 != str2);
+  if (!str2)
+    return str1 != str2;
+  return wcscmp (str1, str2);
+}
+
+#define g_assert_cmpwcs(s1, cmp, s2, s1u8, s2u8) \
+G_STMT_START { \
+  const gunichar2 *__s1 = (s1), *__s2 = (s2); \
+  if (g_wcscmp0 (__s1, __s2) cmp 0) ; else \
+    g_assertion_message_cmpstr (G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, \
+                                #s1u8 " " #cmp " " #s2u8, s1u8, #cmp, s2u8); \
+} G_STMT_END
+
+static void
+test_win32_pathstrip (void)
+{
+  gunichar2 *buf;
+  gsize i;
+#define IDENTITY_TEST(x) { x, x, FALSE }
+  struct
+  {
+    gunichar2 *in;
+    gunichar2 *out;
+    gboolean   result;
+  } testcases[] = {
+    IDENTITY_TEST (L"\\\\?\\V"),
+    IDENTITY_TEST (L"\\\\?\\Vo"),
+    IDENTITY_TEST (L"\\\\?\\Volume{0700f3d3-6d24-11e3-8b2f-806e6f6e6963}\\"),
+    IDENTITY_TEST (L"\\??\\V"),
+    IDENTITY_TEST (L"\\??\\Vo"),
+    IDENTITY_TEST (L"\\??\\Volume{0700f3d3-6d24-11e3-8b2f-806e6f6e6963}\\"),
+    IDENTITY_TEST (L"\\\\?\\\x0441:\\"),
+    IDENTITY_TEST (L"\\??\\\x0441:\\"),
+    IDENTITY_TEST (L"a:\\"),
+    IDENTITY_TEST (L"a:\\b\\c"),
+    IDENTITY_TEST (L"x"),
+#undef IDENTITY_TEST
+    {
+      L"\\\\?\\c:\\",
+             L"c:\\",
+      TRUE,
+    },
+    {
+      L"\\\\?\\C:\\",
+             L"C:\\",
+      TRUE,
+    },
+    {
+      L"\\\\?\\c:\\",
+             L"c:\\",
+      TRUE,
+    },
+    {
+      L"\\\\?\\C:\\",
+             L"C:\\",
+      TRUE,
+    },
+    {
+      L"\\\\?\\C:\\",
+             L"C:\\",
+      TRUE,
+    },
+    { 0, }
+  };
+
+  for (i = 0; testcases[i].in; i++)
+    {
+      gsize str_len = wcslen (testcases[i].in) + 1;
+      gchar *in_u8 = g_utf16_to_utf8 (testcases[i].in, -1, NULL, NULL, NULL);
+      gchar *out_u8 = g_utf16_to_utf8 (testcases[i].out, -1, NULL, NULL, NULL);
+
+      g_assert_nonnull (in_u8);
+      g_assert_nonnull (out_u8);
+
+      buf = g_new0 (gunichar2, str_len);
+      memcpy (buf, testcases[i].in, str_len * sizeof (gunichar2));
+      _g_win32_strip_extended_ntobjm_prefix (buf, &str_len);
+      g_assert_cmpwcs (buf, ==, testcases[i].out, in_u8, out_u8);
+      g_free (buf);
+      g_free (in_u8);
+      g_free (out_u8);
+    }
+  /* Check for correct behaviour on non-NUL-terminated strings */
+  for (i = 0; testcases[i].in; i++)
+    {
+      gsize str_len = wcslen (testcases[i].in) + 1;
+      wchar_t old_endchar;
+      gchar *in_u8 = g_utf16_to_utf8 (testcases[i].in, -1, NULL, NULL, NULL);
+      gchar *out_u8 = g_utf16_to_utf8 (testcases[i].out, -1, NULL, NULL, NULL);
+
+      g_assert_nonnull (in_u8);
+      g_assert_nonnull (out_u8);
+
+      buf = g_new0 (gunichar2, str_len);
+      memcpy (buf, testcases[i].in, (str_len) * sizeof (gunichar2));
+
+      old_endchar = buf[wcslen (testcases[i].out)];
+      str_len -= 1;
+
+      if (testcases[i].result)
+        {
+          /* Given "\\\\?\\C:\\" (len 7, unterminated),
+           * we should get "C:\\" (len 3, unterminated).
+           * Put a character different from "\\" (4-th character of the buffer)
+           * at the end of the unterminated source buffer, into a position
+           * where NUL-terminator would normally be. Then later test that 4-th character
+           * in the buffer is still the old "\\".
+           * After that terminate the string and use normal g_wcscmp0().
+           */
+          buf[str_len] = old_endchar - 1;
+        }
+
+      _g_win32_strip_extended_ntobjm_prefix (buf, &str_len);
+      g_assert_cmpuint (old_endchar, ==, buf[wcslen (testcases[i].out)]);
+      buf[str_len] = L'\0';
+      g_assert_cmpwcs (buf, ==, testcases[i].out, in_u8, out_u8);
+      g_free (buf);
+      g_free (in_u8);
+      g_free (out_u8);
+    }
+}
+
+#endif
+
 int
 main (int   argc,
       char *argv[])
@@ -1018,6 +1151,9 @@ main (int   argc,
 
   g_test_bug_base ("https://gitlab.gnome.org/GNOME/glib/merge_requests/");
 
+#ifdef G_OS_WIN32
+  g_test_add_func ("/fileutils/stdio-win32-pathstrip", test_win32_pathstrip);
+#endif
   g_test_add_func ("/fileutils/build-path", test_build_path);
   g_test_add_func ("/fileutils/build-pathv", test_build_pathv);
   g_test_add_func ("/fileutils/build-filename", test_build_filename);