[PATCH 2/4] Add grub_efi_get_variable

[Matthew Garrett]

Code may wish to obtain system information from EFI variables. Add support
for making the platform call.
---
 ChangeLog                |    6 ++++++
 grub-core/kern/efi/efi.c |   32 ++++++++++++++++++++++++++++++++
 include/grub/efi/api.h   |    4 ++++
 include/grub/efi/efi.h   |    3 ++-
 4 files changed, 44 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ca07786..e662f3d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2012-02-08  Matthew Garrett  <address@hidden>
 
+       * grub-core/kern/efi/efi.c (grub_efi_get_variable): Add new function.
+       * include/grub/efi/efi.h: Likewise.
+       * include/grub/efi/api.h: Add guid for EFI-specified variables.
+
+2012-02-08  Matthew Garrett  <address@hidden>
+
        * include/grub/efi/pci.h: New file to define EFI PCI protocols.
 
 2012-02-07  Vladimir Serbinenko  <address@hidden>
diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
index 9a2c5e6..d366f8a 100644
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -182,6 +182,38 @@ grub_efi_set_virtual_address_map (grub_efi_uintn_t 
memory_map_size,
   return grub_error (GRUB_ERR_IO, "set_virtual_address_map failed");
 }
 
+void *
+grub_efi_get_variable(grub_uint8_t *var, grub_efi_guid_t *guid)
+{
+  grub_efi_status_t status;
+  grub_efi_uintn_t datasize = 0;
+  grub_efi_runtime_services_t *r;
+  grub_efi_char16_t *var16;
+  int i;
+  void *data;
+
+  var16 = grub_malloc((grub_strlen((char *)var) +1) * 2);
+
+  for (i=0; i<(int)grub_strlen((char *)var); i++)
+    var16[i] = var[i];
+  var16[i] = '\0';
+
+  r = grub_efi_system_table->runtime_services;
+
+  status = efi_call_5 (r->get_variable, var16, guid, NULL, &datasize, NULL);
+
+  data = grub_malloc(datasize);
+
+  status = efi_call_5 (r->get_variable, var16, guid, NULL, &datasize, data);
+
+  grub_free(var16);
+
+  if (status == GRUB_EFI_SUCCESS)
+      return data;
+
+  return NULL;
+}
+
 grub_uint64_t
 grub_rtc_get_time_ms (void)
 {
diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h
index b3ec663..c954d03 100644
--- a/include/grub/efi/api.h
+++ b/include/grub/efi/api.h
@@ -1025,6 +1025,10 @@ struct grub_efi_runtime_services
   grub_efi_status_t
   (*convert_pointer) (grub_efi_uintn_t debug_disposition, void **address);
 
+#define GRUB_EFI_GLOBAL_VARIABLE_GUID \
+  { 0x8BE4DF61, 0x93CA, 0x11d2, { 0xAA, 0x0D, 0x00, 0xE0, 0x98, 0x03, 
0x2B,0x8C }}
+
+
   grub_efi_status_t
   (*get_variable) (grub_efi_char16_t *variable_name,
                   grub_efi_guid_t *vendor_guid,
diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 7ecda58..3182972 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -61,7 +61,8 @@ grub_err_t EXPORT_FUNC (grub_efi_set_virtual_address_map) 
(grub_efi_uintn_t memo
                                                           grub_efi_uintn_t 
descriptor_size,
                                                           grub_efi_uint32_t 
descriptor_version,
                                                           
grub_efi_memory_descriptor_t *virtual_map);
-
+void* EXPORT_FUNC (grub_efi_get_variable) (grub_uint8_t *variable,
+                                               grub_efi_guid_t *guid);
 int
 EXPORT_FUNC (grub_efi_compare_device_paths) (const grub_efi_device_path_t *dp1,
                                             const grub_efi_device_path_t *dp2);
-- 
1.7.7.6