Add support for cross-building cloudware images.

If MACHINE_ARCH doesn't match TARGET_ARCH, and we're not in the special
case of building i386 images on an amd64 host, we need to pull in the
qemu-user-static package; this allows us to run some commands inside
the VM disk image chroot, most notably to install packages.

Reviewed by:	gjb
MFC after:	2 weeks
Sponsored by:	FreeBSD/EC2 patreon (https://www.patreon.com/cperciva)

release/Makefile.vm

@@ -39,6 +39,24 @@ VAGRANT-VMWARE_FORMAT=	vmdk
 VAGRANT-VMWARE_DESC=	Vagrant Image for VMWare
 VAGRANT-VMWARE_DISK=	${OSRELEASE}.vmware.${VAGRANT_FORMAT}
 
+emulator-portinstall:
+.if ${TARGET_ARCH} != ${MACHINE_ARCH}
+.if ( ${TARGET_ARCH} != "i386" ) || ( ${MACHINE_ARCH} != "amd64" )
+.if !exists(/usr/local/bin/qemu-${TARGET_ARCH}-static)
+.if exists(${PORTSDIR}/emulators/qemu-user-static/Makefile)
+	env - PATH=$$PATH make -C ${PORTSDIR}/emulators/qemu-user-static BATCH=1 all install clean
+.else
+.if !exists(/usr/local/sbin/pkg-static)
+	env ASSUME_ALWAYS_YES=yes pkg bootstrap -y
+.endif
+	env ASSUME_ALWAYS_YES=yes pkg install -y emulators/qemu-user-static
+.endif
+.endif
+
+QEMUSTATIC=/usr/local/bin/qemu-${TARGET_ARCH}-static
+.endif
+.endif
+
 .if defined(WITH_CLOUDWARE) && !empty(WITH_CLOUDWARE) && !empty(CLOUDWARE)
 . for _CW in ${CLOUDWARE}
 CLOUDTARGETS+=	cw-${_CW:tl}
@@ -53,9 +71,10 @@ ${_CW:tu}IMAGE=	${_CW:tl}.${${_CW:tu}_FORMAT}
 ${_CW:tu}CONF?=	${.CURDIR}/tools/${_CW:tl}.conf
 .  endif
 
-cw-${_CW:tl}:
+cw-${_CW:tl}: emulator-portinstall
 	mkdir -p ${.OBJDIR}/${.TARGET}
 	env TARGET=${TARGET} TARGET_ARCH=${TARGET_ARCH} SWAPSIZE=${SWAPSIZE} \
+		QEMUSTATIC=${QEMUSTATIC} \
 		${.CURDIR}/scripts/mk-vmimage.sh \
 		-C ${.CURDIR}/tools/vmimage.subr -d ${.OBJDIR}/${.TARGET} \
 		-i ${.OBJDIR}/${_CW:tl}.img -s ${VMSIZE} -f ${${_CW:tu}_FORMAT} \

release/tools/ec2.conf

@@ -40,7 +40,7 @@ vm_extra_pre_umount() {
 	# catalogue and install or update pkg when the instance first
 	# launches, so these files would just be replaced anyway; removing
 	# them from the image allows it to boot faster.
-	chroot ${DESTDIR} env ASSUME_ALWAYS_YES=yes \
+	chroot ${DESTDIR} ${EMULATOR} env ASSUME_ALWAYS_YES=yes \
 		/usr/sbin/pkg delete -f -y pkg
 	rm ${DESTDIR}/var/db/pkg/repo-*.sqlite
 

release/tools/vmimage.subr

@@ -148,10 +148,15 @@ vm_install_base() {
 	hostname="$(echo $(uname -o) | tr '[:upper:]' '[:lower:]')"
 	echo "hostname=\"${hostname}\"" >> ${DESTDIR}/etc/rc.conf
 
+	if ! [ -z "${QEMUSTATIC}" ]; then
+		export EMULATOR=/qemu
+		cp ${QEMUSTATIC} ${DESTDIR}/${EMULATOR}
+	fi
+
 	mkdir -p ${DESTDIR}/dev
 	mount -t devfs devfs ${DESTDIR}/dev
-	chroot ${DESTDIR} /usr/bin/newaliases
+	chroot ${DESTDIR} ${EMULATOR} /usr/bin/newaliases
-	chroot ${DESTDIR} /etc/rc.d/ldconfig forcestart
+	chroot ${DESTDIR} ${EMULATOR} /bin/sh /etc/rc.d/ldconfig forcestart
 	umount_loop ${DESTDIR}/dev
 
 	cp /etc/resolv.conf ${DESTDIR}/etc/resolv.conf
@@ -188,9 +193,9 @@ vm_extra_install_packages() {
 	fi
 	mkdir -p ${DESTDIR}/dev
 	mount -t devfs devfs ${DESTDIR}/dev
-	chroot ${DESTDIR} env ASSUME_ALWAYS_YES=yes \
+	chroot ${DESTDIR} ${EMULATOR} env ASSUME_ALWAYS_YES=yes \
 		/usr/sbin/pkg bootstrap -y
-	chroot ${DESTDIR} env ASSUME_ALWAYS_YES=yes \
+	chroot ${DESTDIR} ${EMULATOR} env ASSUME_ALWAYS_YES=yes \
 		/usr/sbin/pkg install -y ${VM_EXTRA_PACKAGES}
 	umount_loop ${DESTDIR}/dev
 
@@ -210,13 +215,16 @@ vm_extra_pre_umount() {
 	# Note: When overriding this function, removing resolv.conf in the
 	# disk image must be included.
 
+	if ! [ -z "${QEMUSTATIC}" ]; then
+		rm -f ${DESTDIR}/${EMULATOR}
+	fi
 	rm -f ${DESTDIR}/etc/resolv.conf
 	return 0
 }
 
 vm_extra_pkg_rmcache() {
 	if [ -e ${DESTDIR}/usr/local/sbin/pkg ]; then
-		chroot ${DESTDIR} env ASSUME_ALWAYS_YES=yes \
+		chroot ${DESTDIR} ${EMULATOR} env ASSUME_ALWAYS_YES=yes \
 			/usr/local/sbin/pkg clean -y -a
 	fi