selftests/kexec: define a set of common functions

Define, update and move get_secureboot_mode() to a common file for use
by other tests.

Updated to check both the efivar SecureBoot-$(UUID) and
SetupMode-$(UUID), based on Dave Young's review.
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NPetr Vorel <pvorel@suse.cz>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/kexec/Makefile

@@ -5,6 +5,7 @@ ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
 
 ifeq ($(ARCH),x86)
 TEST_PROGS := test_kexec_load.sh
+TEST_FILES := kexec_common_lib.sh
 
 include ../lib.mk
 

tools/testing/selftests/kexec/kexec_common_lib.sh

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+# Check efivar SecureBoot-$(the UUID) and SetupMode-$(the UUID).
+# The secure boot mode can be accessed either as the last integer
+# of "od -An -t u1 /sys/firmware/efi/efivars/SecureBoot-*" or from
+# "od -An -t u1 /sys/firmware/efi/vars/SecureBoot-*/data".  The efi
+# SetupMode can be similarly accessed.
+# Return 1 for SecureBoot mode enabled and SetupMode mode disabled.
+get_secureboot_mode()
+{
+	local efivarfs="/sys/firmware/efi/efivars"
+	local secure_boot_file="$efivarfs/../vars/SecureBoot-*/data"
+	local setup_mode_file="$efivarfs/../vars/SetupMode-*/data"
+	local secureboot_mode=0
+	local setup_mode=0
+
+	# Make sure that efivars is mounted in the normal location
+	if ! grep -q "^\S\+ $efivarfs efivarfs" /proc/mounts; then
+		log_skip "efivars is not mounted on $efivarfs"
+	fi
+
+	# Due to globbing, quoting "secure_boot_file" and "setup_mode_file"
+	# is not possible.  (Todo: initialize variables using find or ls.)
+	if [ ! -e $secure_boot_file ] || [ ! -e $setup_mode_file ]; then
+		log_skip "unknown secureboot/setup mode"
+	fi
+
+	secureboot_mode=`od -An -t u1 $secure_boot_file`
+	setup_mode=`od -An -t u1 $setup_mode_file`
+
+	if [ $secureboot_mode -eq 1 ] && [ $setup_mode -eq 0 ]; then
+		log_info "secure boot mode enabled"
+		return 1;
+	fi
+	log_info "secure boot mode not enabled"
+	return 0;
+}

tools/testing/selftests/kexec/test_kexec_load.sh

@@ -5,7 +5,7 @@
 # is booted in secureboot mode.
 
 TEST="$0"
-EFIVARFS="/sys/firmware/efi/efivars"
+. ./kexec_common_lib.sh
 rc=0
 
 # Kselftest framework requirement - SKIP code is 4.
@@ -17,19 +17,8 @@ if [ $(id -ru) -ne 0 ]; then
 	exit $ksft_skip
 fi
 
-# Make sure that efivars is mounted in the normal location
-if ! grep -q "^\S\+ $EFIVARFS efivarfs" /proc/mounts; then
-	echo "$TEST: efivars is not mounted on $EFIVARFS" >&2
-	exit $ksft_skip
-fi
-
-# Get secureboot mode
-file="$EFIVARFS/SecureBoot-*"
-if [ ! -e $file ]; then
-	echo "$TEST: unknown secureboot mode" >&2
-	exit $ksft_skip
-fi
-secureboot=`hexdump $file | awk '{print substr($4,length($4),1)}'`
+get_secureboot_mode
+secureboot=$?
 
 # kexec_load should fail in secure boot mode
 KERNEL_IMAGE="/boot/vmlinuz-`uname -r`"