Cygwin: fetch Windows directory on all platforms and use throughout

Rather than fetching the system Windows directory at dll init time
only on 32 bit, fetch it on all platforms.  Store as WCHAR and
UNICODE_STRING.  Use where appropriate to simplify code.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/dcrt0.cc

@@ -722,20 +722,23 @@ init_windows_system_directory ()
 	api_fatal ("can't find windows system directory");
       windows_system_directory[windows_system_directory_length++] = L'\\';
       windows_system_directory[windows_system_directory_length] = L'\0';
+      /* We need the Windows dir with NT prefix in path.cc.  Note that we
+	 don't append a backslash, because we need the dir without backslash
+	 for the environment. */
+      wcpcpy (windows_directory_buf, L"\\??\\");
+      windows_directory_length =
+	    GetSystemWindowsDirectoryW (windows_directory, MAX_PATH - 4);
+      RtlInitCountedUnicodeString (&windows_directory_path,
+	    windows_directory_buf,
+	    (windows_directory_length + 4) * sizeof (WCHAR));
 #ifdef __i386__
       system_wow64_directory_length =
-	GetSystemWow64DirectoryW (system_wow64_directory, MAX_PATH);
+	    GetSystemWow64DirectoryW (system_wow64_directory, MAX_PATH);
       if (system_wow64_directory_length)
 	{
 	  system_wow64_directory[system_wow64_directory_length++] = L'\\';
 	  system_wow64_directory[system_wow64_directory_length] = L'\0';
 	}
-      /* We need the Windows dir in path.cc. */
-      wcscpy (windows_directory, windows_system_directory);
-      windows_directory_length = windows_system_directory_length - 1;
-      windows_directory[windows_directory_length] = L'\0';
-      while (windows_directory[windows_directory_length - 1] != L'\\')
-	windows_directory[--windows_directory_length] = L'\0';
 #endif /* __i386__ */
     }
 }

winsup/cygwin/fhandler_console.cc

@@ -112,12 +112,11 @@ beep ()
 	     L"Apps", L".Default", L".Default", L".Current", NULL);
   if (r.created ())
     {
-      PWCHAR buf = NULL;
-      UINT len = GetSystemWindowsDirectoryW (buf, 0) * sizeof (WCHAR);
-      buf = (PWCHAR) alloca (len += sizeof (ding));
-      UINT res = GetSystemWindowsDirectoryW (buf, len);
-      if (res && res <= len)
-	r.set_string (L"", wcscat (buf, ding));
+      tmp_pathbuf tp;
+
+      PWCHAR ding_path = tp.w_get ();
+      wcpcpy (wcpcpy (ding_path, windows_directory), ding);
+      r.set_string (L"", ding_path);
     }
   MessageBeep (MB_OK);
 }

winsup/cygwin/globals.cc

@@ -23,12 +23,12 @@ HMODULE NO_COPY hntdll;
 int NO_COPY sigExeced;
 WCHAR windows_system_directory[MAX_PATH];
 UINT windows_system_directory_length;
-#ifdef __i386__
 WCHAR system_wow64_directory[MAX_PATH];
 UINT system_wow64_directory_length;
-WCHAR windows_directory[MAX_PATH];
+WCHAR windows_directory_buf[MAX_PATH];
+PWCHAR windows_directory = windows_directory_buf + 4;
 UINT windows_directory_length;
-#endif /* __i386__ */
+UNICODE_STRING windows_directory_path;
 WCHAR global_progname[NT_MAX_PATH];
 
 /* program exit the program */

winsup/cygwin/path.cc

@@ -3462,19 +3462,11 @@ restart:
 	 file than the final path.  Oh well... */
       if (!fs.is_remote_drive () && wincap.is_wow64 ())
 	{
-	  static UNICODE_STRING wpath;
-	  UNICODE_STRING udpath;
-
-	  /* Create UNICODE_STRING for Windows dir. */
-	  RtlInitCountedUnicodeString (&wpath, windows_directory,
-			windows_directory_length * sizeof (WCHAR));
-	  /* Create a UNICODE_STRING from incoming path, splitting
-	     off the leading "\\??\\" */
-	  RtlInitCountedUnicodeString (&udpath, upath.Buffer + 4,
-			upath.Length - 4 * sizeof (WCHAR));
-	  /* Are we below Windows dir?  Skip the check for inner
-	     symlinks. */
-	  if (RtlEqualUnicodePathPrefix (&udpath, &wpath, TRUE))
+	  /* windows_directory_path is stored without trailing backslash,
+	     so we have to check this explicitely. */
+	  if (RtlEqualUnicodePathPrefix (&upath, &windows_directory_path, TRUE)
+	      && upath.Buffer[windows_directory_path.Length / sizeof (WCHAR)]
+		 == L'\\')
 	    goto file_not_symlink;
 	}
 #endif /* __i386__ */

winsup/cygwin/uinfo.cc

@@ -564,18 +564,7 @@ const char *
 cygheap_user::env_systemroot (const char *name, size_t namelen)
 {
   if (!psystemroot)
-    {
-      int size = GetSystemWindowsDirectoryW (NULL, 0);
-      if (size > 0)
-	{
-	  WCHAR wsystemroot[size];
-	  size = GetSystemWindowsDirectoryW (wsystemroot, size);
-	  if (size > 0)
-	    sys_wcstombs_alloc (&psystemroot, HEAP_STR, wsystemroot);
-	}
-      if (size <= 0)
-	debug_printf ("GetSystemWindowsDirectoryW(), %E");
-    }
+    sys_wcstombs_alloc (&psystemroot, HEAP_STR, windows_directory);
   return psystemroot;
 }