[efi] Add iPXE download protocol

iPXE exposes some extended capabilities via the PXE FILE API to allow
NBPs such as pxelinux to use protocols other than TFTP.  Provide an
equivalent interface as a UEFI protocol so that EFI binaries may also
take advantage of iPXE's extended capabilities.

This can be used with a patched version of elilo, for example:

  http://comments.gmane.org/gmane.comp.boot-loaders.elilo.general/147

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

1 files changed, 124 insertions, 2 deletions

diff --git a/src/image/efi_image.c b/src/image/efi_image.c
index 0575496c..9b9e7600 100644
--- a/src/image/efi_image.c
+++ b/src/image/efi_image.c
@@ -19,13 +19,95 @@
 FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <errno.h>
+#include <stdlib.h>
 #include <ipxe/efi/efi.h>
 #include <ipxe/image.h>
 #include <ipxe/init.h>
 #include <ipxe/features.h>
+#include <ipxe/uri.h>
 
 FEATURE ( FEATURE_IMAGE, "EFI", DHCP_EB_FEATURE_EFI, 1 );
 
+/** EFI loaded image protocol GUID */
+static EFI_GUID efi_loaded_image_protocol_guid =
+	EFI_LOADED_IMAGE_PROTOCOL_GUID;
+
+/**
+ * Create a Unicode command line for the image
+ *
+ * @v image             EFI image
+ * @v devpath_out       Device path to pass to image (output)
+ * @v cmdline_out       Unicode command line (output)
+ * @v cmdline_len_out   Length of command line in bytes (output)
+ * @ret rc              Return status code
+ */
+static int efi_image_make_cmdline ( struct image *image,
+				    EFI_DEVICE_PATH **devpath_out,
+				    VOID **cmdline_out,
+				    UINT32 *cmdline_len_out ) {
+	char *uri;
+	size_t uri_len;
+	FILEPATH_DEVICE_PATH *devpath;
+	EFI_DEVICE_PATH *endpath;
+	size_t devpath_len;
+	CHAR16 *cmdline;
+	UINT32 cmdline_len;
+	size_t args_len = 0;
+	UINT32 i;
+
+	/* Get the URI string of the image */
+	uri_len = unparse_uri ( NULL, 0, image->uri, URI_ALL ) + 1;
+
+	/* Compute final command line length */
+	if ( image->cmdline ) {
+		args_len = strlen ( image->cmdline ) + 1;
+	}
+	cmdline_len = args_len + uri_len;
+
+	/* Allocate space for the uri, final command line and device path */
+	cmdline = malloc ( cmdline_len * sizeof ( CHAR16 ) + uri_len
+			   + SIZE_OF_FILEPATH_DEVICE_PATH
+			   + uri_len * sizeof ( CHAR16 )
+			   + sizeof ( EFI_DEVICE_PATH ) );
+	if ( ! cmdline )
+		return -ENOMEM;
+	uri = (char *) ( cmdline + cmdline_len );
+	devpath = (FILEPATH_DEVICE_PATH *) ( uri + uri_len );
+	endpath = (EFI_DEVICE_PATH *) ( (char *) devpath
+					+ SIZE_OF_FILEPATH_DEVICE_PATH
+					+ uri_len * sizeof ( CHAR16 ) );
+
+	/* Build the iPXE device path */
+	devpath->Header.Type = MEDIA_DEVICE_PATH;
+	devpath->Header.SubType = MEDIA_FILEPATH_DP;
+	devpath_len = SIZE_OF_FILEPATH_DEVICE_PATH
+			+ uri_len * sizeof ( CHAR16 );
+	devpath->Header.Length[0] = devpath_len & 0xFF;
+	devpath->Header.Length[1] = devpath_len >> 8;
+	endpath->Type = END_DEVICE_PATH_TYPE;
+	endpath->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
+	endpath->Length[0] = 4;
+	endpath->Length[1] = 0;
+	unparse_uri ( uri, uri_len, image->uri, URI_ALL );
+
+	/* Convert to Unicode */
+	for ( i = 0 ; i < uri_len ; i++ ) {
+		cmdline[i] = uri[i];
+		devpath->PathName[i] = uri[i];
+	}
+	if ( image->cmdline ) {
+		cmdline[uri_len - 1] = ' ';
+	}
+	for ( i = 0 ; i < args_len ; i++ ) {
+		cmdline[i + uri_len] = image->cmdline[i];
+	}
+
+	*devpath_out = &devpath->Header;
+	*cmdline_out = cmdline;
+	*cmdline_len_out = cmdline_len * sizeof ( CHAR16 );
+	return 0;
+}
+
 /**
  * Execute EFI image
  *
@@ -34,7 +116,12 @@ FEATURE ( FEATURE_IMAGE, "EFI", DHCP_EB_FEATURE_EFI, 1 );
  */
 static int efi_image_exec ( struct image *image ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	union {
+		EFI_LOADED_IMAGE_PROTOCOL *image;
+		void *interface;
+	} loaded;
 	EFI_HANDLE handle;
+	EFI_HANDLE device_handle = NULL;
 	UINTN exit_data_size;
 	CHAR16 *exit_data;
 	EFI_STATUS efirc;
@@ -47,21 +134,56 @@ static int efi_image_exec ( struct image *image ) {
 		/* Not an EFI image */
 		DBGC ( image, "EFIIMAGE %p could not load: %s\n",
 		       image, efi_strerror ( efirc ) );
-		return -ENOEXEC;
+		rc = -ENOEXEC;
+		goto err_load_image;
 	}
 
+	/* Get the loaded image protocol for the newly loaded image */
+	efirc = bs->OpenProtocol ( handle, &efi_loaded_image_protocol_guid,
+				   &loaded.interface, efi_image_handle,
+				   NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL );
+	if ( efirc ) {
+		/* Should never happen */
+		rc = EFIRC_TO_RC ( efirc );
+		goto err_open_protocol;
+	}
+
+	/* Pass an iPXE download protocol to the image */
+	if ( ( rc = efi_download_install ( &device_handle ) ) != 0 ) {
+		DBGC ( image, "EFIIMAGE %p could not install iPXE download "
+		       "protocol: %s\n", image, strerror ( rc ) );
+		goto err_download_install;
+	}
+	loaded.image->DeviceHandle = device_handle;
+	loaded.image->ParentHandle = efi_loaded_image;
+	if ( ( rc = efi_image_make_cmdline ( image, &loaded.image->FilePath,
+				       &loaded.image->LoadOptions,
+				       &loaded.image->LoadOptionsSize ) ) != 0 )
+		goto err_make_cmdline;
+
 	/* Start the image */
 	if ( ( efirc = bs->StartImage ( handle, &exit_data_size,
 					&exit_data ) ) != 0 ) {
 		DBGC ( image, "EFIIMAGE %p returned with status %s\n",
 		       image, efi_strerror ( efirc ) );
+		rc = EFIRC_TO_RC ( efirc );
+		goto err_start_image;
 	}
-	rc = EFIRC_TO_RC ( efirc );
 
+	/* Success */
+	rc = 0;
+
+ err_start_image:
+	free ( loaded.image->LoadOptions );
+ err_make_cmdline:
+	efi_download_uninstall ( device_handle );
+ err_download_install:
+ err_open_protocol:
 	/* Unload the image.  We can't leave it loaded, because we
 	 * have no "unload" operation.
 	 */
 	bs->UnloadImage ( handle );
+ err_load_image:
 
 	return rc;
 }