librechroot: Support using qemu for ARM builds on x86 via binfmt_misc.

1 files changed, 35 insertions, 4 deletions

diff --git a/src/chroot-tools/librechroot b/src/chroot-tools/librechroot
index e6b3a3a..cc416d5 100755
--- a/src/chroot-tools/librechroot
+++ b/src/chroot-tools/librechroot
@@ -49,28 +49,59 @@ readonly _makechrootpkg="$(librelib chroot/makechrootpkg.sh)"
 arch_nspawn_flags=()
 sysd_nspawn_flags=()
 
+hack_arch_nspawn_flags() {
+	local copydir="$1"
+
+	local makepkg_conf="$copydir/etc/makepkg.conf"
+
+	OPTIND=1
+	set -- ${arch_nspawn_flags+"${arch_nspawn_flags[@]}"}
+	while getopts 'hC:M:c:f:s' arg; do
+		case "$arg" in
+			M) makepkg_conf="$OPTARG" ;;
+			*) :;;
+		esac
+	done
+
+	local CARCH
+	if [[ -f "$makepkg_conf" ]]; then
+		eval $(grep '^CARCH=' "$makepkg_conf")
+	else
+		CARCH="$(uname -m)"
+	fi
+
+	if [[ "$CARCH" == armv7h ]] && ! setarch armv7l 2>/dev/null; then
+		arch_nspawn_flags+=(-f /usr/bin/qemu-arm-static -s)
+	fi
+}
+
 # Usage: arch-nspawn $copydir $cmd...
-arch-nspawn() {
+arch-nspawn() (
 	local copydir=$1; shift
 	local cmd=("$@")
 
+	hack_arch_nspawn_flags "$copydir"
+
 	"$_arch_nspawn" \
 	    ${arch_nspawn_flags+"${arch_nspawn_flags[@]}"} \
 	    "$copydir" \
 	    ${sysd_nspawn_flags+"${sysd_nspawn_flags[@]}"} \
 	    -- \
 	    "${cmd[@]}"
-}
+)
 
 # Usage: mkarchroot $copydir $pkgs...
-mkarchroot() {
+mkarchroot() (
 	local copydir=$1; shift
 	local pkgs=("$@")
+
+	hack_arch_nspawn_flags "$copydir"
+
 	unshare -m "$_mkarchroot" \
 	    ${arch_nspawn_flags+"${arch_nspawn_flags[@]}"} \
 	    "$copydir" \
 	    "${pkgs[@]}"
-}
+)
 
 # Usage: _makechrootpkg $function $arguments...
 # Don't load $_makechrootpkg directly because it doesn't work with -euE