Add a conditional point for a debugger to attach.

Signed-off-by: Peter Jones <pjones@redhat.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/fallback.c b/fallback.c
index 8489b2e8..cf578d69 100644
--- a/fallback.c
+++ b/fallback.c
@@ -11,6 +11,7 @@
 #include <efilib.h>
 
 #include "ucs2.h"
+#include "variables.h"
 
 EFI_LOADED_IMAGE *this_image = NULL;
 
@@ -791,6 +792,35 @@ try_start_first_option(EFI_HANDLE parent_image_handle)
 	return rc;
 }
 
+EFI_GUID SHIM_LOCK_GUID = { 0x605dab50, 0xe046, 0x4300, {0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23} };
+extern EFI_STATUS
+efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *systab);
+
+static void
+__attribute__((__optimize__("0")))
+debug_hook(void)
+{
+	EFI_GUID guid = SHIM_LOCK_GUID;
+	UINT8 *data = NULL;
+	UINTN dataSize = 0;
+	EFI_STATUS efi_status;
+	volatile register int x = 0;
+	extern char _etext, _edata;
+
+	efi_status = get_variable(L"SHIM_DEBUG", &data, &dataSize, guid);
+	if (EFI_ERROR(efi_status)) {
+		return;
+	}
+
+	if (x)
+		return;
+
+	x = 1;
+	Print(L"add-symbol-file /usr/lib/debug/usr/share/shim/"
+	      EFI_ARCH"/fallback.debug %p -s .data %p\n", &_etext,
+	      &_edata);
+}
+
 EFI_STATUS
 efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *systab)
 {
@@ -798,6 +828,11 @@ efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *systab)
 
 	InitializeLib(image, systab);
 
+	/*
+	 * if SHIM_DEBUG is set, wait for a debugger to attach.
+	 */
+	debug_hook();
+
 	rc = uefi_call_wrapper(BS->HandleProtocol, 3, image, &LoadedImageProtocol, (void *)&this_image);
 	if (EFI_ERROR(rc)) {
 		Print(L"Error: could not find loaded image: %d\n", rc);