[efi] Accept a command line passed to an iPXE image via LoadOptions

Treat a command line passed to iPXE via UEFI LoadOptions as an image
to be registered at startup, as is already done for the .lkrn, .pxe,
and .exe BIOS images.

Originally-implemented-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/efi/efi_cmdline.h

@@ -0,0 +1,18 @@
+#ifndef _IPXE_EFI_CMDLINE_H
+#define _IPXE_EFI_CMDLINE_H
+
+/** @file
+ *
+ * EFI command line
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+#include <wchar.h>
+
+extern const wchar_t *efi_cmdline;
+extern size_t efi_cmdline_len;
+
+#endif /* _IPXE_EFI_CMDLINE_H */

src/include/ipxe/errfile.h

@@ -401,6 +401,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_dynkeymap	      ( ERRFILE_OTHER | 0x00580000 )
 #define ERRFILE_pci_cmd		      ( ERRFILE_OTHER | 0x00590000 )
 #define ERRFILE_dhe		      ( ERRFILE_OTHER | 0x005a0000 )
+#define ERRFILE_efi_cmdline	      ( ERRFILE_OTHER | 0x005b0000 )
 
 /** @} */
 

src/interface/efi/efi_cmdline.c

@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2023 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * EFI command line
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+#include <ipxe/init.h>
+#include <ipxe/image.h>
+#include <ipxe/script.h>
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_cmdline.h>
+
+/** EFI command line (may not be wNUL-terminated */
+const wchar_t *efi_cmdline;
+
+/** Length of EFI command line (in bytes) */
+size_t efi_cmdline_len;
+
+/** Internal copy of the command line */
+static char *efi_cmdline_copy;
+
+/**
+ * Free command line image
+ *
+ * @v refcnt		Reference count
+ */
+static void efi_cmdline_free ( struct refcnt *refcnt ) {
+	struct image *image = container_of ( refcnt, struct image, refcnt );
+
+	DBGC ( image, "CMDLINE freeing command line\n" );
+	free ( efi_cmdline_copy );
+}
+
+/** Embedded script representing the command line */
+static struct image efi_cmdline_image = {
+	.refcnt = REF_INIT ( efi_cmdline_free ),
+	.name = "<CMDLINE>",
+	.type = &script_image_type,
+};
+
+/** Colour for debug messages */
+#define colour &efi_cmdline_image
+
+/**
+ * Initialise EFI command line
+ *
+ * @ret rc		Return status code
+ */
+static int efi_cmdline_init ( void ) {
+	char *cmdline;
+	size_t len;
+	int rc;
+
+	/* Do nothing if no command line was specified */
+	if ( ! efi_cmdline_len ) {
+		DBGC ( colour, "CMDLINE found no command line\n" );
+		return 0;
+	}
+
+	/* Allocate ASCII copy of command line */
+	len = ( ( efi_cmdline_len / sizeof ( efi_cmdline[0] ) ) + 1 /* NUL */ );
+	efi_cmdline_copy = malloc ( len );
+	if ( ! efi_cmdline_copy ) {
+		rc = -ENOMEM;
+		goto err_alloc;
+	}
+	cmdline = efi_cmdline_copy;
+	snprintf ( cmdline, len, "%ls", efi_cmdline );
+	DBGC ( colour, "CMDLINE found command line \"%s\"\n", cmdline );
+
+	/* Mark command line as consumed */
+	efi_cmdline_len = 0;
+
+	/* Strip image name and surrounding whitespace */
+	while ( isspace ( *cmdline ) )
+		cmdline++;
+	while ( *cmdline && ( ! isspace ( *cmdline ) ) )
+		cmdline++;
+	while ( isspace ( *cmdline ) )
+		cmdline++;
+	DBGC ( colour, "CMDLINE using command line \"%s\"\n", cmdline );
+
+	/* Prepare and register image */
+	efi_cmdline_image.data = virt_to_user ( cmdline );
+	efi_cmdline_image.len = strlen ( cmdline );
+	if ( efi_cmdline_image.len &&
+	     ( ( rc = register_image ( &efi_cmdline_image ) ) != 0 ) ) {
+		DBGC ( colour, "CMDLINE could not register command line: %s\n",
+		       strerror ( rc ) );
+		goto err_register_image;
+	}
+
+	/* Drop our reference to the image */
+	image_put ( &efi_cmdline_image );
+
+	return 0;
+
+ err_register_image:
+	image_put ( &efi_cmdline_image );
+ err_alloc:
+	return rc;
+}
+
+/**
+ * EFI command line startup function
+ *
+ */
+static void efi_cmdline_startup ( void ) {
+	int rc;
+
+	/* Initialise command line */
+	if ( ( rc = efi_cmdline_init() ) != 0 ) {
+		/* No way to report failure */
+		return;
+	}
+}
+
+/** Command line and initrd initialisation function */
+struct startup_fn efi_cmdline_startup_fn __startup_fn ( STARTUP_NORMAL ) = {
+	.name = "efi_cmdline",
+	.startup = efi_cmdline_startup,
+};

src/interface/efi/efi_init.c

@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_driver.h>
 #include <ipxe/efi/efi_path.h>
+#include <ipxe/efi/efi_cmdline.h>
 #include <ipxe/efi/Protocol/LoadedImage.h>
 
 /** Image handle passed to entry point */
@@ -254,6 +255,10 @@ EFI_STATUS efi_init ( EFI_HANDLE image_handle,
 	DBGC ( systab, "EFI image base address %p\n",
 	       efi_loaded_image->ImageBase );
 
+	/* Record command line */
+	efi_cmdline = efi_loaded_image->LoadOptions;
+	efi_cmdline_len = efi_loaded_image->LoadOptionsSize;
+
 	/* Get loaded image's device handle's device path */
 	if ( ( efirc = bs->OpenProtocol ( efi_loaded_image->DeviceHandle,
 				&efi_device_path_protocol_guid,