app-emulation/qemu: generate init.d script from upstream settings

app-emulation/qemu/files/qemu-binfmt.initd.head

@@ -0,0 +1,64 @@
+#!/sbin/openrc-run
+# Copyright 1999-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+# Enable automatic non-native program execution by the kernel.
+
+# Defaulting to OC should be safe because it comes down to:
+#  - do we trust the interp itself to not be malicious?  yes; we built it.
+#  - do we trust the programs we're running?  ish; same permission as native
+#    binaries apply.  so if user can do bad stuff natively, cross isn't worse.
+: ${QEMU_BINFMT_FLAGS:=OC}
+
+depend() {
+	after procfs
+}
+
+start() {
+	ebegin "Registering qemu-user binaries (flags: ${QEMU_BINFMT_FLAGS})"
+
+	if [ ! -d /proc/sys/fs/binfmt_misc ] ; then
+		modprobe -q binfmt_misc
+	fi
+
+	if [ ! -d /proc/sys/fs/binfmt_misc ] ; then
+		eend 1 "You need support for 'misc binaries' in your kernel!"
+		return
+	fi
+
+	if [ ! -f /proc/sys/fs/binfmt_misc/register ] ; then
+		mount -t binfmt_misc -o nodev,noexec,nosuid \
+			binfmt_misc /proc/sys/fs/binfmt_misc >/dev/null 2>&1
+		eend $? || return
+	fi
+
+	# Probe the native cpu type so we don't try registering them.
+	local cpu="$(uname -m)"
+	case "${cpu}" in
+	armv[4-9]*)
+		cpu="arm"
+		;;
+	i386|i486|i586|i686|i86pc|BePC|x86_64)
+		cpu="i386"
+		;;
+	m68k)
+		cpu="m68k"
+		;;
+	mips*)
+		cpu="mips"
+		;;
+	"Power Macintosh"|ppc|ppc64)
+		cpu="ppc"
+		;;
+	s390*)
+		cpu="s390"
+		;;
+	sh*)
+		cpu="sh"
+		;;
+	sparc*)
+		cpu="sparc"
+		;;
+	esac
+
+	# Register the interpreter for each cpu except for the native one.

app-emulation/qemu/files/qemu-binfmt.initd.tail

@@ -0,0 +1,14 @@
+	eend 0
+}
+
+stop() {
+	# We unregister everything in the "qemu-xxx" namespace.
+	ebegin "Unregistering qemu-user binaries"
+	local f
+	for f in /proc/sys/fs/binfmt_misc/qemu-* ; do
+		if [ -f "${f}" ] ; then
+			echo '-1' > "${f}"
+		fi
+	done
+	eend 0
+}

app-emulation/qemu/qemu-9999.ebuild

@@ -560,13 +560,58 @@ qemu_python_install() {
 	python_doscript "${S}/scripts/qmp/qemu-ga-client"
 }
 
+# Generate the /etc/init.d/qemu-binfmt script which registers the user handlers.
+generate_initd() {
+	local out="${T}/qemu-binfmt"
+	local d="${T}/binfmt.d"
+
+	einfo "Generating qemu init.d script"
+
+	# Generate the debian fragments first.
+	mkdir -p "${d}"
+	"${S}"/scripts/qemu-binfmt-conf.sh \
+		--debian \
+		--exportdir "${d}" \
+		--qemu-path "${EPREFIX}/usr/bin" \
+		|| die
+	# Then turn the fragments into a shell script we can source.
+	sed -E -i \
+		-e 's:^([^ ]+) (.*)$:\1="\2":' \
+		"${d}"/* || die
+
+	# Generate the init.d script by assembling the fragments from above.
+	local f qcpu package interpreter magic mask
+	cat "${FILESDIR}"/qemu-binfmt.initd.head >"${out}" || die
+	for f in "${d}"/qemu-* ; do
+		source "${f}"
+
+		# Normalize the cpu logic like we do in the init.d for the native cpu.
+		qcpu=${package#qemu-}
+		case ${qcpu} in
+		arm*)   qcpu="arm";;
+		mips*)  qcpu="mips";;
+		ppc*)   qcpu="ppc";;
+		s390*)  qcpu="s390";;
+		sh*)    qcpu="sh";;
+		sparc*) qcpu="sparc";;
+		esac
+
+		cat <<EOF >>"${out}"
+	if [ "\${cpu}" != "${qcpu}" -a -x "${interpreter}" ] ; then
+		echo ':${package}:M::${magic}:${mask}:${interpreter}:'"\${QEMU_BINFMT_FLAGS}" >/proc/sys/fs/binfmt_misc/register
+	fi
+EOF
+	done
+	cat "${FILESDIR}"/qemu-binfmt.initd.tail >>"${out}" || die
+}
+
 src_install() {
 	if [[ -n ${user_targets} ]]; then
 		cd "${S}/user-build"
 		emake DESTDIR="${ED}" install
 
-		# Install binfmt handler init script for user targets
-		newinitd "${FILESDIR}/qemu-binfmt.initd-r1" qemu-binfmt
+		# Install binfmt handler init script for user targets.
+		doinitd "${T}/qemu-binfmt"
 	fi
 
 	if [[ -n ${softmmu_targets} ]]; then