Support emulation of an ARM environment on Intel systems.

qemu-user is used to emulate an ARM chroot environment
that is used to compile the system for ARM target systems.

make.sh

@@ -34,16 +34,13 @@ NICE=10								# Nice level
 MAX_RETRIES=1							# prefetch/check loop
 BUILD_IMAGES=1							# Flash and Xen Downloader
 KVER=`grep --max-count=1 VER lfs/linux | awk '{ print $3 }'`
-MACHINE=`uname -m`
 GIT_TAG=$(git tag | tail -1)					# Git Tag
 GIT_LASTCOMMIT=$(git log | head -n1 | cut -d" " -f2 |head -c8)	# Last commit
 TOOLCHAINVER=7
 
-BUILDMACHINE=$MACHINE
-    if [ "$MACHINE" = "x86_64" ]; then
-        BUILDMACHINE="i686";
-    fi
-
+# New architecture variables
+BUILD_ARCH="$(uname -m)"
+BUILDMACHINE="${BUILD_ARCH}"
 
 # Debian specific settings
 if [ ! -e /etc/debian_version ]; then
@@ -68,6 +65,8 @@ mkdir $BASEDIR/log/ 2>/dev/null
 # Include funtions
 . tools/make-functions
 
+configure_target "default"
+
 if [ -f .config ]; then
 	. .config
 fi
@@ -241,7 +240,7 @@ prepareenv() {
 
 buildtoolchain() {
     local error=false
-    case "${MACHINE}:$(uname -m)" in
+    case "${TARGET_ARCH}:${BUILD_ARCH}" in
         # x86
         i586:i586|i586:i686|i586:x86_64)
             # These are working.
@@ -898,6 +897,22 @@ ipfirepackages() {
   rm -rf  $BASEDIR/build/install/packages/*
 }
 
+while [ $# -gt 0 ]; do
+	case "${1}" in
+		--target=*)
+			configure_target "${1#--target=}"
+			;;
+		-*)
+			exiterror "Unknown configuration option: ${1}"
+			;;
+		*)
+			# Found a command, so exit options parsing.
+			break
+			;;
+	esac
+	shift
+done
+
 # See what we're supposed to do
 case "$1" in 
 build)

tools/make-functions

@@ -60,6 +60,69 @@ WARN="\\033[1;35m"
 FAIL="\\033[1;31m"
 NORMAL="\\033[0;39m"
 
+configure_target() {
+	local target_arch="${1}"
+
+	if [ "${target_arch}" = "default" ]; then
+		target_arch="$(configure_target_guess)"
+	fi
+
+	case "${target_arch}" in
+		i586)
+			BUILDTARGET="${TARGET_ARCH}-pc-linux-gnu"
+			CROSSTARGET="${BUILD_ARCH}-cross-linux-gnu"
+			CFLAGS_ARCH="-march=i586 -fomit-frame-pointer"
+			;;
+
+		armv5tel)
+			BUILDTARGET="${TARGET_ARCH}-unknown-linux-gnueabi"
+			CROSSTARGET="${BUILD_ARCH}-cross-linux-gnueabi"
+			CFLAGS_ARCH="-march=armv5te -mfloat-abi=soft -fomit-frame-pointer"
+			MACHINE_TYPE="arm"
+			;;
+
+		*)
+			exiterror "Cannot build for architure ${target_arch}"
+			;;
+	esac
+
+	# Check if the QEMU helper is available if needed.
+	if qemu_is_required "${target_arch}"; then
+		local qemu_target_helper="$(qemu_find_target_helper_name "${target_arch}")"
+
+		if [ -n "${qemu_target_helper}" ]; then
+			QEMU_TARGET_HELPER="${qemu_target_helper}"
+		else
+			exiterror "Could not find a binfmt_misc helper entry for ${target_arch}"
+		fi
+	fi
+
+	TARGET_ARCH="${target_arch}"
+
+	# Old variable names
+	MACHINE="${TARGET_ARCH}"
+
+	CFLAGS="-O2 -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fPIC"
+	CFLAGS="${CFLAGS} -fstack-protector-all --param=ssp-buffer-size=4 ${CFLAGS_ARCH}"
+	CXXFLAGS="${CFLAGS}"
+	C2FLAGS="${CFLAGS}"
+	CXX2FLAGS="${CXXFLAGS}"
+}
+
+configure_target_guess() {
+	case "${BUILD_ARCH}" in
+		x86_64|i686|i586)
+			echo "i586"
+			;;
+		armv7*|armv6*|armv5*)
+			echo "armv5tel"
+			;;
+		*)
+			exiterror "Cannot guess target architecture"
+			;;
+	esac
+}
+
 evaluate() {
 	if [ "$?" -eq "0" ]; then
 		beautify message DONE
@@ -217,30 +280,6 @@ get_pkg_ver()
 	echo "$PKG_VER"
 } # End of get_pkg_ver()
 
-if [ 'x86_64' = $MACHINE -o 'i686' = $MACHINE -o 'i586' = $MACHINE ]; then
-	echo "`date -u '+%b %e %T'`: Machine is iX86 (or equivalent)" >> $LOGFILE
-	MACHINE=i586
-	CROSSTARGET=${MACHINE}-cross-linux-gnu
-	BUILDTARGET=i586-pc-linux-gnu
-	CFLAGS_ARCH="${GLOBAL_CFLAGS} -march=i586 -fomit-frame-pointer"
-elif [ 'armv5tejl' = $MACHINE -o 'armv5tel' = $MACHINE -o 'armv6l' = $MACHINE -o 'armv7l' = $MACHINE ]; then
-	echo "`date -u '+%b %e %T'`: Machine is ARM (or equivalent)" >> $LOGFILE
-	MACHINE=armv5tel
-	MACHINE_TYPE=arm
-	CROSSTARGET=${MACHINE}-cross-linux-gnueabi
-	BUILDTARGET=${MACHINE}-unknown-linux-gnueabi
-	CFLAGS_ARCH="-march=armv5te -mfloat-abi=soft -fomit-frame-pointer"
-else
-	echo "`date -u '+%b %e %T'`: Can't determine your architecture - $MACHINE"
-	exit 1
-fi
-
-CFLAGS="-O2 -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fPIC"
-CFLAGS="${CFLAGS} -fstack-protector-all --param=ssp-buffer-size=4 ${CFLAGS_ARCH}"
-CXXFLAGS="${CFLAGS}"
-C2FLAGS="${CFLAGS}"
-CXX2FLAGS="${CXXFLAGS}"
-
 # Define immediately
 stdumount() {
 	umount $BASEDIR/build/sys			2>/dev/null;
@@ -282,16 +321,130 @@ fake_environ() {
 	env="${env} UTS_RELEASE=${KVER}"
 
 	# Fake machine version.
-	env="${env} UTS_MACHINE=${MACHINE}"
+	env="${env} UTS_MACHINE=${TARGET_ARCH}"
 
 	echo "${env}"
 }
 
+qemu_environ() {
+	local env
+
+	# Don't add anything if qemu is not used.
+	if ! qemu_is_required; then
+		return
+	fi
+
+	# Set default qemu options
+	case "${TARGET_ARCH}" in
+		arm*)
+			QEMU_CPU="${QEMU_CPU:-cortex-a9}"
+
+			env="${env} QEMU_CPU=${QEMU_CPU}"
+			;;
+	esac
+
+	# Enable QEMU strace
+	#env="${env} QEMU_STRACE=1"
+
+	echo "${env}"
+}
+
+qemu_is_required() {
+	local target_arch="${1}"
+
+	if [ -z "${target_arch}" ]; then
+		target_arch="${TARGET_ARCH}"
+	fi
+
+	case "${BUILD_ARCH},${target_arch}" in
+		x86_64,arm*|i?86,arm*)
+			return 0
+			;;
+		*)
+			return 1
+			;;
+	esac
+}
+
+qemu_install_helper() {
+	# Do nothing, if qemu is not required
+	if ! qemu_is_required; then
+		return 0
+	fi
+
+	if [ -z "${QEMU_TARGET_HELPER}" ]; then
+		exiterror "QEMU_TARGET_HELPER not set"
+	fi
+
+	# Check if the helper is already installed.
+	if [ -x "${LFS}${QEMU_TARGET_HELPER}" ]; then
+		return 0
+	fi
+
+	# Try to find a suitable binary that we can install
+	# to the build environment.
+	local file
+	for file in "${QEMU_TARGET_HELPER}" "${QEMU_TARGET_HELPER}-static"; do
+		# file must exist and be executable.
+		[ -x "${file}" ] || continue
+
+		# Must be static.
+		file_is_static "${file}" || continue
+
+		local dirname="${LFS}$(dirname "${file}")"
+		mkdir -p "${dirname}"
+
+		install -m 755 "${file}" "${LFS}${QEMU_TARGET_HELPER}"
+		return 0
+	done
+
+	exiterror "Could not find a statically-linked QEMU emulator: ${QEMU_TARGET_HELPER}"
+}
+
+qemu_find_target_helper_name() {
+	local target_arch="${1}"
+
+	local magic
+	case "${target_arch}" in
+		arm*)
+			magic="7f454c4601010100000000000000000002002800"
+			;;
+	esac
+
+	[ -z "${magic}" ] && return 1
+
+	local file
+	for file in /proc/sys/fs/binfmt_misc/*; do
+		# Search for the file with the correct magic value.
+		grep -qE "^magic ${magic}$" "${file}" || continue
+
+		local interpreter="$(grep "^interpreter" "${file}" | awk '{ print $2 }')"
+
+		[ -n "${interpreter}" ] || continue
+		[ "${interpreter:0:1}" = "/" ] || continue
+		[ -x "${interpreter}" ] || continue
+
+		echo "${interpreter}"
+		return 0
+	done
+
+	return 1
+}
+
+file_is_static() {
+	local file="${1}"
+
+	file ${file} 2>/dev/null | grep -q "statically linked"
+}
+
 entershell() {
 	if [ ! -e $BASEDIR/build/usr/src/lfs/ ]; then
 		exiterror "No such file or directory: $BASEDIR/build/usr/src/lfs/"
 	fi
 
+	# Install QEMU helper, if needed
+	qemu_install_helper
+
 	echo "Entering to a shell inside LFS chroot, go out with exit"
 	chroot $LFS /tools/bin/env -i HOME=/root TERM=$TERM PS1='\u:\w\$ ' \
 		PATH=/tools/ccache/bin:/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \
@@ -308,6 +461,7 @@ entershell() {
 		MACHINE_TYPE="$MACHINE_TYPE" \
 		KGCC="ccache /usr/bin/gcc" \
 		$(fake_environ) \
+		$(qemu_environ) \
 		/tools/bin/bash
 	if [ $? -ne 0 ]; then
 			beautify message FAIL
@@ -410,6 +564,9 @@ lfsmake2() {
 	lfsmakecommoncheck $*
 	[ $? == 1 ] && return 0
 
+	# Install QEMU helper, if needed
+	qemu_install_helper
+
 	local PKG_TIME_START=`date +%s`
 	chroot $LFS /tools/bin/env -i 	HOME=/root \
 						TERM=$TERM PS1='\u:\w\$ ' \
@@ -426,6 +583,7 @@ lfsmake2() {
 						CROSSTARGET="${CROSSTARGET}" \
 						MACHINE="$MACHINE" \
 						MACHINE_TYPE="$MACHINE_TYPE" \
+						$(qemu_environ) \
 						$(fake_environ) \
 						/tools/bin/bash -x -c "cd /usr/src/lfs && \
 						make -f $* LFS_BASEDIR=/usr/src install" >>$LOGFILE 2>&1
@@ -446,6 +604,9 @@ ipfiremake() {
 	lfsmakecommoncheck $*
 	[ $? == 1 ] && return 0
 
+	# Install QEMU helper, if needed
+	qemu_install_helper
+
 	local PKG_TIME_START=`date +%s`
 	chroot $LFS /tools/bin/env -i 	HOME=/root \
 						TERM=$TERM PS1='\u:\w\$ ' \
@@ -463,6 +624,7 @@ ipfiremake() {
 						CROSSTARGET="${CROSSTARGET}" \
 						MACHINE="$MACHINE" \
 						MACHINE_TYPE="$MACHINE_TYPE" \
+						$(qemu_environ) \
 						$(fake_environ) \
 						/bin/bash -x -c "cd /usr/src/lfs && \
 						make -f $* LFS_BASEDIR=/usr/src install" >>$LOGFILE 2>&1
@@ -483,6 +645,9 @@ ipfiredist() {
 	lfsmakecommoncheck $*
 	[ $? == 1 ] && return 0
 	
+	# Install QEMU helper, if needed
+	qemu_install_helper
+
 	local PKG_TIME_START=`date +%s`
 	chroot $LFS /tools/bin/env -i 	HOME=/root \
 					TERM=$TERM PS1='\u:\w\$ ' \
@@ -498,6 +663,7 @@ ipfiredist() {
 					CROSSTARGET="${CROSSTARGET}" \
 					MACHINE="$MACHINE" \
 					MACHINE_TYPE="$MACHINE_TYPE" \
+					$(qemu_environ) \
 					$(fake_environ) \
 					/bin/bash -x -c "cd /usr/src/lfs && \
 					make -f $1 LFS_BASEDIR=/usr/src dist" >>$LOGFILE 2>&1
@@ -518,6 +684,9 @@ installmake() {
 	lfsmakecommoncheck $*
 	[ $? == 1 ] && return 0
 
+	# Install QEMU helper, if needed
+	qemu_install_helper
+
 	local PKG_TIME_START=`date +%s`
 	chroot $LFS /tools/bin/env -i 	HOME=/root \
 						TERM=$TERM PS1='\u:\w\$ ' \