mxgrub: Add --reboot

mxgrub/mxgrub

@@ -11,6 +11,7 @@ sub USAGE { return <<"EOF" }
     $0 --update    : only scan /boot and rewrite grub.cfg
     $0 --initramfs : update /boot/grub/initramfs.igz from /project/admin/initramfs
     $0 --test      : perform miscellaneous tests (VX50 board)
+    $0 --reboot    : attempt kexec reboot of selected kernel
 EOF
 
 sub sys {
@@ -352,16 +353,26 @@ sub cmd_initramfs {
 	sys('bash','-c','cd /project/admin/initramfs;find .|cpio -H newc -o | gzip > /boot/grub/initramfs.igz');
 }
 
+sub cmd_reboot {
+	my $chosen=get_chosen();
+	my $image=label_to_image($chosen);
+	-e "/boot/$image" or die "/boot/$image: no such file\n";
+	sys('sync');
+	sys('kexec',"/boot/$image",'--reuse-cmdline','--initrd=/boot/grub/initramfs.igz');
+}
+
 umask 022;
 check_grub_installation();
 
-our ($opt_list,$opt_update,$opt_initramfs,$opt_test);
+our ($opt_list,$opt_update,$opt_initramfs,$opt_test,$opt_reboot);
 
 GetOptions(
 		'list'      => \$opt_list,
 		'update'    => \$opt_update,
 		'initramfs' => \$opt_initramfs,
 		'test'      => \$opt_test,
+		'reboot'    => \$opt_reboot,
+
 ) or die USAGE;
 
 $opt_list && $opt_update and die USAGE;
@@ -391,6 +402,9 @@ if ($opt_list) {
 	} else {
 		print "System booted using UEFI: no\n";
 	}
+} elsif ($opt_reboot) {
+	@ARGV==0 or die USAGE;
+	cmd_reboot();
 } else {
 	@ARGV==1 or die USAGE;
 	cmd_install($ARGV[0]);