sd-boot: add EFI boot manager and stub loader

1 files changed, 106 insertions, 0 deletions

diff --git a/src/sd-boot/stub.c b/src/sd-boot/stub.c
new file mode 100644
index 0000000000..e18faac669
--- /dev/null
+++ b/src/sd-boot/stub.c
@@ -0,0 +1,106 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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
+ * Lesser General Public License for more details.
+ *
+ * Copyright (C) 2015 Kay Sievers <kay@vrfy.org>
+ */
+
+#include <efi.h>
+#include <efilib.h>
+
+#include "util.h"
+#include "pefile.h"
+#include "linux.h"
+
+/* magic string to find in the binary image */
+static const char __attribute__((used)) magic[] = "#### LoaderInfo: stub " VERSION " ####";
+
+static const EFI_GUID global_guid = EFI_GLOBAL_VARIABLE;
+
+EFI_STATUS efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *sys_table) {
+        EFI_LOADED_IMAGE *loaded_image;
+        EFI_FILE *root_dir;
+        CHAR16 *loaded_image_path;
+        CHAR8 *b;
+        UINTN size;
+        BOOLEAN secure = FALSE;
+        CHAR8 *sections[] = {
+                (UINT8 *)".cmdline",
+                (UINT8 *)".linux",
+                (UINT8 *)".initrd",
+                NULL
+        };
+        UINTN addrs[ELEMENTSOF(sections)-1] = {};
+        UINTN offs[ELEMENTSOF(sections)-1] = {};
+        UINTN szs[ELEMENTSOF(sections)-1] = {};
+        CHAR8 *cmdline = NULL;
+        UINTN cmdline_len;
+        EFI_STATUS err;
+
+        InitializeLib(image, sys_table);
+
+        err = uefi_call_wrapper(BS->OpenProtocol, 6, image, &LoadedImageProtocol, (VOID **)&loaded_image,
+                                image, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+        if (EFI_ERROR(err)) {
+                Print(L"Error getting a LoadedImageProtocol handle: %r ", err);
+                uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
+                return err;
+        }
+
+        root_dir = LibOpenRoot(loaded_image->DeviceHandle);
+        if (!root_dir) {
+                Print(L"Unable to open root directory: %r ", err);
+                uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
+                return EFI_LOAD_ERROR;
+        }
+
+        loaded_image_path = DevicePathToStr(loaded_image->FilePath);
+
+        if (efivar_get_raw(&global_guid, L"SecureBoot", &b, &size) == EFI_SUCCESS) {
+                if (*b > 0)
+                        secure = TRUE;
+                FreePool(b);
+        }
+
+        err = pefile_locate_sections(root_dir, loaded_image_path, sections, addrs, offs, szs);
+        if (EFI_ERROR(err)) {
+                Print(L"Unable to locate embedded .linux section: %r ", err);
+                uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
+                return err;
+        }
+
+        if (szs[0] > 0)
+                cmdline = (CHAR8 *)(loaded_image->ImageBase + addrs[0]);
+
+        cmdline_len = szs[0];
+
+        /* if we are not in secure boot mode, accept a custom command line and replace the built-in one */
+        if (!secure && loaded_image->LoadOptionsSize > 0) {
+                CHAR16 *options;
+                CHAR8 *line;
+                UINTN i;
+
+                options = (CHAR16 *)loaded_image->LoadOptions;
+                cmdline_len = (loaded_image->LoadOptionsSize / sizeof(CHAR16)) * sizeof(CHAR8);
+                line = AllocatePool(cmdline_len);
+                for (i = 0; i < cmdline_len; i++)
+                        line[i] = options[i];
+                cmdline = line;
+        }
+
+        err = linux_exec(image, cmdline, cmdline_len,
+                         (UINTN)loaded_image->ImageBase + addrs[1],
+                         (UINTN)loaded_image->ImageBase + addrs[2], szs[2]);
+
+        Print(L"Execution of embedded linux image failed: %r\n", err);
+        uefi_call_wrapper(BS->Stall, 1, 3 * 1000 * 1000);
+        return err;
+}