src/boot/efi/stub.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /* This program is free software; you can redistribute it and/or modify it
   4  * under the terms of the GNU Lesser General Public License as published by
   5  * the Free Software Foundation; either version 2.1 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * Copyright (C) 2015 Kay Sievers <kay@vrfy.org>
  14  */
  15
  16 #include <efi.h>
  17 #include <efilib.h>
  18
  19 #include "disk.h"
  20 #include "graphics.h"
  21 #include "linux.h"
  22 #include "pefile.h"
  23 #include "splash.h"
  24 #include "util.h"
  25
  26 /* magic string to find in the binary image */
  27 static const char __attribute__((used)) magic[] = "#### LoaderInfo: systemd-stub " VERSION " ####";
  28
  29 static const EFI_GUID global_guid = EFI_GLOBAL_VARIABLE;
  30
  31 EFI_STATUS efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *sys_table) {
  32         EFI_LOADED_IMAGE *loaded_image;
  33         EFI_FILE *root_dir;
  34         CHAR16 *loaded_image_path;
  35         CHAR8 *b;
  36         UINTN size;
  37         BOOLEAN secure = FALSE;
  38         CHAR8 *sections[] = {
  39                 (UINT8 *)".cmdline",
  40                 (UINT8 *)".linux",
  41                 (UINT8 *)".initrd",
  42                 (UINT8 *)".splash",
  43                 NULL
  44         };
  45         UINTN addrs[ELEMENTSOF(sections)-1] = {};
  46         UINTN offs[ELEMENTSOF(sections)-1] = {};
  47         UINTN szs[ELEMENTSOF(sections)-1] = {};
  48         CHAR8 *cmdline = NULL;
  49         UINTN cmdline_len;
  50         CHAR16 uuid[37];
  51         EFI_STATUS err;
  52
  53         InitializeLib(image, sys_table);
  54
  55         err = uefi_call_wrapper(BS->OpenProtocol, 6, image, &LoadedImageProtocol, (VOID **)&loaded_image,
  56                                 image, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
  57         if (EFI_ERROR(err)) {
  58                 Print(L"Error getting a LoadedImageProtocol handle: %r ", err);
  59                 uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
  60                 return err;
  61         }
  62
  63         root_dir = LibOpenRoot(loaded_image->DeviceHandle);
  64         if (!root_dir) {
  65                 Print(L"Unable to open root directory: %r ", err);
  66                 uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
  67                 return EFI_LOAD_ERROR;
  68         }
  69
  70         loaded_image_path = DevicePathToStr(loaded_image->FilePath);
  71
  72         if (efivar_get_raw(&global_guid, L"SecureBoot", &b, &size) == EFI_SUCCESS) {
  73                 if (*b > 0)
  74                         secure = TRUE;
  75                 FreePool(b);
  76         }
  77
  78         err = pefile_locate_sections(root_dir, loaded_image_path, sections, addrs, offs, szs);
  79         if (EFI_ERROR(err)) {
  80                 Print(L"Unable to locate embedded .linux section: %r ", err);
  81                 uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
  82                 return err;
  83         }
  84
  85         if (szs[0] > 0)
  86                 cmdline = (CHAR8 *)(loaded_image->ImageBase + addrs[0]);
  87
  88         cmdline_len = szs[0];
  89
  90         /* if we are not in secure boot mode, accept a custom command line and replace the built-in one */
  91         if (!secure && loaded_image->LoadOptionsSize > 0) {
  92                 CHAR16 *options;
  93                 CHAR8 *line;
  94                 UINTN i;
  95
  96                 options = (CHAR16 *)loaded_image->LoadOptions;
  97                 cmdline_len = (loaded_image->LoadOptionsSize / sizeof(CHAR16)) * sizeof(CHAR8);
  98                 line = AllocatePool(cmdline_len);
  99                 for (i = 0; i < cmdline_len; i++)
 100                         line[i] = options[i];
 101                 cmdline = line;
 102         }
 103
 104         /* export the device path this image is started from */
 105         if (disk_get_part_uuid(loaded_image->DeviceHandle, uuid) == EFI_SUCCESS)
 106                 efivar_set(L"LoaderDevicePartUUID", uuid, FALSE);
 107
 108         if (szs[3] > 0)
 109                 graphics_splash((UINT8 *)((UINTN)loaded_image->ImageBase + addrs[3]), szs[3], NULL);
 110
 111         err = linux_exec(image, cmdline, cmdline_len,
 112                          (UINTN)loaded_image->ImageBase + addrs[1],
 113                          (UINTN)loaded_image->ImageBase + addrs[2], szs[2]);
 114
 115         graphics_mode(FALSE);
 116         Print(L"Execution of embedded linux image failed: %r\n", err);
 117         uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
 118         return err;
 119 }