/*
 *  VAS_EBOOT  --  GRand Unified Bootloader
 *  Copyright (C) 2023  Free Software Foundation, Inc.
 *
 *  VAS_EBOOT 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.
 *
 *  VAS_EBOOT 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 VAS_EBOOT.  If not, see <http://www.gnu.org/licenses/>.
 *
 *  Implementation of the Boot Loader Interface.
 */

#include <VasEBoot/charset.h>
#include <VasEBoot/efi/api.h>
#include <VasEBoot/efi/disk.h>
#include <VasEBoot/efi/efi.h>
#include <VasEBoot/err.h>
#include <VasEBoot/extcmd.h>
#include <VasEBoot/gpt_partition.h>
#include <VasEBoot/misc.h>
#include <VasEBoot/mm.h>
#include <VasEBoot/partition.h>
#include <VasEBoot/tpm.h>
#include <VasEBoot/types.h>

VAS_EBOOT_MOD_LICENSE ("GPLv3+");

#define MODNAME "bli"

static const VasEBoot_guid_t bli_vendor_guid = VAS_EBOOT_EFI_VENDOR_BOOT_LOADER_INTERFACE_GUID;

static VasEBoot_err_t
get_part_uuid (const char *device_name, char **part_uuid)
{
  VasEBoot_device_t device;
  VasEBoot_err_t status = VAS_EBOOT_ERR_NONE;
  VasEBoot_disk_t disk = NULL;
  struct VasEBoot_gpt_partentry entry;

  device = VasEBoot_device_open (device_name);
  if (device == NULL)
    return VasEBoot_error (VasEBoot_errno, N_("cannot open device: %s"), device_name);

  if (device->disk == NULL)
    {
      VasEBoot_dprintf ("bli", "%s is not a disk device, partuuid skipped\n", device_name);
      *part_uuid = NULL;
      VasEBoot_device_close (device);
      return VAS_EBOOT_ERR_NONE;
    }

  if (device->disk->partition == NULL)
    {
      VasEBoot_dprintf ("bli", "%s has no partition, partuuid skipped\n", device_name);
      *part_uuid = NULL;
      VasEBoot_device_close (device);
      return VAS_EBOOT_ERR_NONE;
    }

  disk = VasEBoot_disk_open (device->disk->name);
  if (disk == NULL)
    {
      status = VasEBoot_error (VasEBoot_errno, N_("cannot open disk: %s"), device_name);
      VasEBoot_device_close (device);
      return status;
    }

  if (VasEBoot_strcmp (device->disk->partition->partmap->name, "gpt") != 0)
    {
      status = VasEBoot_error (VAS_EBOOT_ERR_BAD_PART_TABLE,
			   N_("this is not a GPT partition table: %s"), device_name);
      goto fail;
    }

  if (VasEBoot_disk_read (disk, device->disk->partition->offset,
		      device->disk->partition->index, sizeof (entry), &entry) != VAS_EBOOT_ERR_NONE)
    {
      status = VasEBoot_error (VasEBoot_errno, N_("read error: %s"), device_name);
      goto fail;
    }

  *part_uuid = VasEBoot_xasprintf ("%pG", &entry.guid);
  if (*part_uuid == NULL)
    status = VasEBoot_errno;

 fail:
  VasEBoot_disk_close (disk);
  VasEBoot_device_close (device);

  return status;
}

static VasEBoot_err_t
set_loader_device_part_uuid (void)
{
  VasEBoot_efi_loaded_image_t *image;
  char *device_name;
  VasEBoot_err_t status = VAS_EBOOT_ERR_NONE;
  char *part_uuid = NULL;

  image = VasEBoot_efi_get_loaded_image (VasEBoot_efi_image_handle);
  if (image == NULL)
    return VasEBoot_error (VAS_EBOOT_ERR_BAD_DEVICE, N_("unable to find boot device"));

  device_name = VasEBoot_efidisk_get_device_name (image->device_handle);
  if (device_name == NULL)
    return VasEBoot_error (VAS_EBOOT_ERR_BAD_DEVICE, N_("unable to find boot device"));

  status = get_part_uuid (device_name, &part_uuid);

  if (status == VAS_EBOOT_ERR_NONE && part_uuid)
    status = VasEBoot_efi_set_variable_to_string ("LoaderDevicePartUUID", &bli_vendor_guid, part_uuid,
					      VAS_EBOOT_EFI_VARIABLE_BOOTSERVICE_ACCESS |
					      VAS_EBOOT_EFI_VARIABLE_RUNTIME_ACCESS);
  else
    VasEBoot_error (status, N_("unable to determine partition UUID of boot device"));

  VasEBoot_free (part_uuid);
  VasEBoot_free (device_name);
  return status;
}

static VasEBoot_err_t
set_loader_active_pcr_banks (void)
{
  VasEBoot_efi_uint32_t active_pcr_banks;
  char *active_pcr_banks_str;
  VasEBoot_err_t status;

  active_pcr_banks = VasEBoot_tpm2_active_pcr_banks();
  active_pcr_banks_str = VasEBoot_xasprintf ("0x%08x", active_pcr_banks);
  if (active_pcr_banks_str == NULL)
    return VasEBoot_error (VAS_EBOOT_ERR_OUT_OF_MEMORY, N_("cannot allocate active PCR banks string"));

  status = VasEBoot_efi_set_variable_to_string ("LoaderTpm2ActivePcrBanks",
					     &bli_vendor_guid,
					     active_pcr_banks_str,
					     VAS_EBOOT_EFI_VARIABLE_BOOTSERVICE_ACCESS |
					     VAS_EBOOT_EFI_VARIABLE_RUNTIME_ACCESS);
  VasEBoot_free (active_pcr_banks_str);
  return status;
}

VAS_EBOOT_MOD_INIT (bli)
{
  VasEBoot_efi_set_variable_to_string ("LoaderInfo", &bli_vendor_guid, PACKAGE_STRING,
				   VAS_EBOOT_EFI_VARIABLE_BOOTSERVICE_ACCESS |
				   VAS_EBOOT_EFI_VARIABLE_RUNTIME_ACCESS);
  set_loader_device_part_uuid ();
  set_loader_active_pcr_banks ();
  /* No error here is critical, other than being logged */
  VasEBoot_print_error ();
}