[PATCH 1/1] meta/isar-bootstrap: deactivate daemon activation in chroot environment

[claudius.heine.ext@siemens.com]

From: Claudius Heine <ch@denx.de>

Daemons are started in postinst steps of debian packages. Those daemons
should not be started within the chroot environment, since they will be
left running.

This commit disables the execution of daemons the same way upstream
debian does it in debootstrap and debian-installer, by replacing deamon
executing binaries with fake ones.

This is then reversed in the image cleanup step.

Signed-off-by: Claudius Heine <ch@denx.de>
---
 meta/classes/isar-bootstrap-helper.bbclass    |   2 +
 .../isar-bootstrap/files/chroot-setup.sh      | 133 ++++++++++++++++++
 .../isar-bootstrap/isar-bootstrap.bb          |  11 +-
 3 files changed, 144 insertions(+), 2 deletions(-)
 create mode 100644 meta/recipes-core/isar-bootstrap/files/chroot-setup.sh

diff --git a/meta/classes/isar-bootstrap-helper.bbclass b/meta/classes/isar-bootstrap-helper.bbclass
index 4195a88..6101e9a 100644
--- a/meta/classes/isar-bootstrap-helper.bbclass
+++ b/meta/classes/isar-bootstrap-helper.bbclass
@@ -74,5 +74,7 @@ setup_root_file_system() {
             /usr/bin/apt-get autoremove --purge --yes
         sudo -E chroot "$ROOTFSDIR" \
             /usr/bin/apt-get clean
+        sudo "$ROOTFSDIR/chroot-setup.sh" "cleanup" "$ROOTFSDIR"
+        sudo rm -f "$ROOTFSDIR/chroot-setup.sh"
     fi
 }
diff --git a/meta/recipes-core/isar-bootstrap/files/chroot-setup.sh b/meta/recipes-core/isar-bootstrap/files/chroot-setup.sh
new file mode 100644
index 0000000..801e005
--- /dev/null
+++ b/meta/recipes-core/isar-bootstrap/files/chroot-setup.sh
@@ -0,0 +1,133 @@
+#!/bin/sh
+# This file is based on:
+# https://salsa.debian.org/installer-team/debian-installer-utils/blob/master/chroot-setup.sh
+
+usage() {
+	cat <<-EOF 1>&2
+		Script to setup and cleanup chroot environments.
+		This script setups chroot environments so that
+		startup of daemons from debian package scripts
+		is prevented.
+
+		Usage:
+		$(basename $0) [command] [parameters]
+		commands:
+		    setup [target path]    Setup chroot environment
+		    cleanup [target path]  Cleanup chroot environment
+	EOF
+}
+
+check_target() {
+	TARGET="${1:-""}"
+
+	if [ -z "${TARGET}" ]; then
+		echo "Please set a target." 1>&2
+		echo 1>&2
+		usage
+		return 1
+	fi
+
+	# Bail out if directories we need are not there
+	if [ ! -d "/${TARGET}/sbin" ] || [ ! -d "/${TARGET}/usr/sbin" ] || \
+	   [ ! -d "/${TARGET}/proc" ]; then
+		echo "Target '${TARGET}' does not exist or does contain"\
+			"required directories" 1>&2
+		echo 1>&2
+		usage
+		return 1
+	fi
+
+	return 0
+}
+
+divert () {
+	TARGET="${1:-""}"
+
+	check_target "${TARGET}" || return 1
+
+	chroot "/${TARGET}" dpkg-divert --quiet --add --divert "$2.REAL" --rename "$2"
+}
+
+undivert () {
+	TARGET="${1:-""}"
+
+	check_target "${TARGET}" || return 1
+
+	rm -f "/${TARGET}$2"
+	chroot "/${TARGET}" dpkg-divert --quiet --remove --rename "$2"
+}
+
+chroot_setup() {
+	TARGET="${1:-""}"
+
+	check_target "${TARGET}" || return 1
+
+	# Create a policy-rc.d to stop maintainer scripts using invoke-rc.d
+	# from running init scripts. In case of maintainer scripts that do not
+	# use invoke-rc.d, add a dummy start-stop-daemon.
+	cat > "/${TARGET}/usr/sbin/policy-rc.d" <<-EOF
+		#!/bin/sh
+		exit 101
+	EOF
+	chmod a+rx "/${TARGET}/usr/sbin/policy-rc.d"
+
+	if [ -e "/${TARGET}/sbin/start-stop-daemon" ]; then
+		divert "${TARGET}" /sbin/start-stop-daemon
+	fi
+	cat > "/${TARGET}/sbin/start-stop-daemon" <<-EOF
+		#!/bin/sh
+		echo 1>&2
+		echo 'Warning: Fake start-stop-daemon called, doing nothing.' 1>&2
+		exit 0
+	EOF
+	chmod a+rx "/${TARGET}/sbin/start-stop-daemon"
+
+	# If Upstart is in use, add a dummy initctl to stop it starting jobs.
+	if [ -x "/${TARGET}/sbin/initctl" ]; then
+		divert "${TARGET}" /sbin/initctl
+		cat > "/${TARGET}/sbin/initctl" <<-EOF
+			#!/bin/sh
+			if [ "\$1" = version ]; then exec /sbin/initctl.REAL "\$@"; fi
+			echo 1>&2
+			echo 'Warning: Fake initctl called, doing nothing.' 1>&2
+			exit 0
+		EOF
+		chmod a+rx "/${TARGET}/sbin/initctl"
+	fi
+}
+
+chroot_cleanup() {
+	TARGET="${1:-""}"
+
+	check_target "${TARGET}" || return 1
+
+	rm -f "/${TARGET}/usr/sbin/policy-rc.d"
+	undivert "${TARGET}" /sbin/start-stop-daemon
+	if [ -x "/${TARGET}/sbin/initctl.REAL" ]; then
+		undivert "${TARGET}" /sbin/initctl
+	fi
+}
+
+main() {
+	CMD="${1:-""}"
+
+	if [ -z "${CMD}" ]; then
+		usage
+		return 1
+	fi
+	shift
+
+	case "${CMD}" in
+		"setup")
+			chroot_setup $@;;
+		"cleanup")
+			chroot_cleanup $@;;
+		*)
+			echo "Unknown command '${CMD}'." 1>&2
+			echo 1>&2
+			usage
+			return 1;;
+	esac
+}
+
+main $@
diff --git a/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb b/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb
index 02c09aa..5b44f8a 100644
--- a/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb
+++ b/meta/recipes-core/isar-bootstrap/isar-bootstrap.bb
@@ -13,7 +13,8 @@ FILESPATH_prepend := "${THISDIR}/files:"
 SRC_URI = " \
     file://isar-apt.conf \
     file://isar-apt-fallback.conf \
-    file://locale"
+    file://locale \
+    file://chroot-setup.sh"
 PV = "1.0"
 
 WORKDIR = "${TMPDIR}/work/${DISTRO}-${DISTRO_ARCH}/${PN}"
@@ -201,6 +202,12 @@ do_set_locale() {
 }
 addtask set_locale after do_bootstrap
 
+do_setup_chroot() {
+    sudo install -v -m755 "${WORKDIR}/chroot-setup.sh" "${ROOTFSDIR}/chroot-setup.sh"
+    sudo "${ROOTFSDIR}/chroot-setup.sh" "setup" "${ROOTFSDIR}"
+}
+addtask setup_chroot before do_build after do_bootstrap
+
 def get_host_release():
     import platform
     rel = platform.release()
@@ -237,7 +244,7 @@ do_apt_update() {
     sudo -E chroot "${ROOTFSDIR}" /usr/bin/apt-get dist-upgrade -y \
                                       -o Debug::pkgProblemResolver=yes
 }
-addtask apt_update before do_build after do_apt_config_install do_set_locale
+addtask apt_update before do_build after do_apt_config_install do_set_locale do_setup_chroot
 
 python() {
     if d.getVar("ISAR_BOOTSTRAP_TARBALL", True):
-- 
2.17.1