[PATCH] Add apple_set_os command

[Andreas Heider <andreas@heider.io>]

The EFI on current macbooks configures hardware differently depending
on wether it is booting Mac OS X or a different os, for example
disabling the internal GPU completely on some models.

Mac OS X identifies itself using a custom EFI protocol.

This adds a command that fakes the os identification, making all
hardware accessible.
---
 grub-core/Makefile.core.def         |  6 +++
 grub-core/commands/efi/applesetos.c | 82 +++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)
 create mode 100644 grub-core/commands/efi/applesetos.c

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 42443bc..dc9c4de 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -742,6 +742,12 @@ module = {
 };
 
 module = {
+  name = applesetos;
+  common = commands/efi/applesetos.c;
+  enable = efi;
+};
+
+module = {
   name = blocklist;
   common = commands/blocklist.c;
 };
diff --git a/grub-core/commands/efi/applesetos.c b/grub-core/commands/efi/applesetos.c
new file mode 100644
index 0000000..9464307
--- /dev/null
+++ b/grub-core/commands/efi/applesetos.c
@@ -0,0 +1,82 @@
+/* applesetos.c - Pretend to be Mac OS X. */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 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 <grub/efi/api.h>
+#include <grub/efi/efi.h>
+#include <grub/command.h>
+/* For NULL.  */
+#include <grub/mm.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+#define GRUB_EFI_APPLE_SET_OS_PROTOCOL_GUID  \
+  { 0xc5c5da95, 0x7d5c, 0x45e6, \
+    { 0xb2, 0xf1, 0x3f, 0xd5, 0x2b, 0xb1, 0x00, 0x77 } \
+  }
+
+struct grub_efi_apple_set_os_interface
+{
+  grub_efi_uint64_t version;
+  void (*set_os_version) (const grub_efi_char8_t *os_version);
+  void (*set_os_vendor) (const grub_efi_char8_t *os_vendor);
+};
+typedef struct grub_efi_apple_set_os_interface grub_efi_apple_set_os_interface_t;
+
+static const grub_efi_char8_t apple_os_version[] = "Mac OS X 10.9";
+static const grub_efi_char8_t apple_os_vendor[]  = "Apple Inc.";
+
+static grub_err_t
+grub_cmd_apple_set_os (grub_command_t cmd __attribute__ ((unused)),
+                       int argc __attribute__ ((unused)),
+                       char **args __attribute__ ((unused)))
+{
+  grub_efi_guid_t apple_set_os_guid = GRUB_EFI_APPLE_SET_OS_PROTOCOL_GUID;
+  grub_efi_apple_set_os_interface_t *set_os;
+  set_os = grub_efi_locate_protocol (&apple_set_os_guid, 0);
+  if (!set_os) {
+    return grub_error (GRUB_ERR_FILE_NOT_FOUND,
+                       "Could not locate the apple set os protocol.");
+  }
+
+  if (set_os->version != 0)
+    {
+      efi_call_1 (set_os->set_os_version, apple_os_version);
+      grub_printf("Set os version to %s\n", apple_os_version);
+    }
+
+  if (set_os->version == 2)
+    {
+      efi_call_1 (set_os->set_os_vendor, apple_os_vendor);
+      grub_printf("Set os vendor to %s\n", apple_os_vendor);
+    }
+
+  return 0;
+}
+
+static grub_command_t cmd;
+
+GRUB_MOD_INIT(applesetos)
+{
+  cmd = grub_register_command ("apple_set_os", grub_cmd_apple_set_os, NULL,
+                               "Register as Apple Inc. Mac OS X 10.9.");
+}
+
+GRUB_MOD_FINI(applesetos)
+{
+  grub_unregister_command (cmd);
+}
-- 
1.8.5.2