[efi] Expose downloaded images via EFI_SIMPLE_FILE_SYSTEM_PROTOCOL

Expose iPXE's images as a UEFI file system, allowing the booted image
to access all images downloaded by iPXE.

This functionality is complementary to the custom iPXE download
protocol.  The iPXE download protocol allows a booted image to utilise
iPXE to download arbitrary URIs, but requires the booted image to
specifically support the custom iPXE download protocol.  The new
functionality limits the booted image to accessing only files that
were already downloaded by iPXE (e.g. as part of a script), but can
work with any generic UEFI image (e.g. the UEFI shell).  Both
protocols are provided simultaneously, and are attached to the SNP
device handle.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 13 insertions, 21 deletions

diff --git a/src/interface/efi/efi_download.c b/src/interface/efi/efi_download.c
index 250946e2..7b19ad3a 100644
--- a/src/interface/efi/efi_download.c
+++ b/src/interface/efi/efi_download.c
@@ -25,7 +25,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/iobuf.h>
 #include <ipxe/xfer.h>
 #include <ipxe/efi/efi.h>
-#include <ipxe/efi/ipxe_download.h>
+#include <ipxe/efi/efi_download.h>
 
 /** iPXE download protocol GUID */
 static EFI_GUID ipxe_download_protocol_guid
@@ -187,47 +187,39 @@ static IPXE_DOWNLOAD_PROTOCOL ipxe_download_protocol_interface = {
 };
 
 /**
- * Create a new device handle with a iPXE download protocol attached to it.
+ * Install iPXE download protocol
  *
- * @v device_handle	Newly created device handle (output)
+ * @v handle		EFI handle
  * @ret rc		Return status code
  */
-int efi_download_install ( EFI_HANDLE *device_handle ) {
+int efi_download_install ( EFI_HANDLE *handle ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	EFI_STATUS efirc;
-	EFI_HANDLE handle = NULL;
-	if (efi_loaded_image->DeviceHandle) { /* TODO: ensure handle is the NIC (maybe efi_image has a better way to indicate the handle doing SNP?) */
-		handle = efi_loaded_image->DeviceHandle;
-	}
 
-	DBG ( "Installing ipxe protocol interface (%p)... ",
-	      &ipxe_download_protocol_interface );
 	efirc = bs->InstallMultipleProtocolInterfaces (
-			&handle,
+			handle,
 			&ipxe_download_protocol_guid,
 			&ipxe_download_protocol_interface,
 			NULL );
 	if ( efirc ) {
-		DBG ( "failed (%s)\n", efi_strerror ( efirc ) );
+		DBG ( "Could not install download protocol: %s\n",
+		      efi_strerror ( efirc ) );
 		return EFIRC_TO_RC ( efirc );
 	}
 
-	DBG ( "success (%p)\n", handle );
-	*device_handle = handle;
 	return 0;
 }
 
 /**
- * Remove the iPXE download protocol from the given handle, and if nothing
- * else is attached, destroy the handle.
+ * Uninstall iPXE download protocol
  *
- * @v device_handle	EFI device handle to remove from
+ * @v handle		EFI handle
  */
-void efi_download_uninstall ( EFI_HANDLE device_handle ) {
+void efi_download_uninstall ( EFI_HANDLE handle ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 
 	bs->UninstallMultipleProtocolInterfaces (
-			device_handle,
-			ipxe_download_protocol_guid,
-			ipxe_download_protocol_interface );
+			handle,
+			&ipxe_download_protocol_guid,
+			&ipxe_download_protocol_interface, NULL );
 }