Move OS-dependent files to grub-core/osdep and document it.

grub-core/osdep/windows/random.c

@@ -0,0 +1,55 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 1992-1999,2001,2003,2004,2005,2009,2010,2011,2012,2013 Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include <grub/types.h>
+#include <grub/crypto.h>
+#include <grub/auth.h>
+#include <grub/emu/misc.h>
+#include <grub/util/misc.h>
+#include <grub/i18n.h>
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <windows.h>
+#include <wincrypt.h>
+
+int
+grub_get_random (void *out, grub_size_t len)
+{
+  HCRYPTPROV   hCryptProv;
+  if (!CryptAcquireContext (&hCryptProv,
+			    NULL,
+			    MS_DEF_PROV,
+			    PROV_RSA_FULL,
+			    CRYPT_VERIFYCONTEXT))
+    return 1;
+  if (!CryptGenRandom (hCryptProv, len, out))
+    {
+      CryptReleaseContext (hCryptProv, 0);
+      return 1;
+    }
+
+  CryptReleaseContext (hCryptProv, 0);
+
+  return 0;
+}