ubiquity 18.04.14 / lib / chroot-setup.sh

# Setup for using apt to install packages in /target.

mountpoints () {
	cut -d" " -f2 /proc/mounts | sort | uniq
}

# Make sure mtab in the chroot reflects the currently mounted partitions.
update_mtab() {
	mtab=/target/etc/mtab

	if [ -h "$mtab" ]; then
		logger -t $0 "warning: $mtab won't be updated since it is a symlink."
		return 0
	fi

	egrep '^[^ ]+ /target' /proc/mounts | (
	while read devpath mountpoint fstype options n1 n2 ; do
		devpath=`mapdevfs $devpath || echo $devpath`
		mountpoint="${mountpoint#/target}"
		# mountpoint for root will be empty
		if [ -z "$mountpoint" ] ; then
			mountpoint="/"
		fi
		echo $devpath $mountpoint $fstype $options $n1 $n2
	done ) > $mtab
}

divert () {
	chroot /target dpkg-divert --quiet --add --divert "$1.REAL" --rename "$1"
}

undivert () {
	rm -f "/target$1"
	chroot /target dpkg-divert --quiet --remove --rename "$1"
}

chroot_setup () {
	# Bail out if directories we need are not there
	if [ ! -d /target/sbin ] || [ ! -d /target/usr/sbin ] || \
	   [ ! -d /target/proc ]; then
		return 1
	fi
	if [ -d /sys/devices ] && [ ! -d /target/sys ]; then
		return 1
	fi

	if [ -e /var/run/chroot-setup.lock ]; then
		cat >&2 <<EOF
apt-install or in-target is already running, so you cannot run either of
them again until the other instance finishes. You may be able to use
'chroot /target ...' instead.
EOF
		return 1
	fi
	touch /var/run/chroot-setup.lock

	# Create a policy-rc.d to stop maintainer scripts using invoke-rc.d 
	# from running init scripts. In case of maintainer scripts that don't
	# 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 /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 /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

	# Record the current mounts
	mountpoints > /tmp/mount.pre

	case `udpkg --print-os` in
	        "linux")
			# Some packages (eg. the kernel-image package) require a mounted
			# /proc/. Only mount it if not mounted already
			if [ ! -f /target/proc/cmdline ]; then
				mount -t proc proc /target/proc
			fi

			# For installing >=2.6.14 kernels we also need sysfs mounted
			# Only mount it if not mounted already
			if [ ! -d /target/sys/devices ]; then
				mount -t sysfs sysfs /target/sys
			fi

			# In Lenny, /dev/ lacks the pty devices, so we need devpts mounted
			if [ ! -e /target/dev/pts/0 ]; then
				mkdir -p /target/dev/pts
				mount -t devpts devpts -o noexec,nosuid,gid=5,mode=620 \
					/target/dev/pts
			fi

			if ! mountpoints | grep -q '^/target/run$'; then
				mount --bind /run /target/run
			fi
		;;
	        "kfreebsd")
			# Some packages (eg. the kernel-image package) require a mounted
			# /proc/. Only mount it if not mounted already
			if [ ! -f /target/proc/cmdline ]; then
				mount -t linprocfs proc /target/proc
			fi
			# Some package might need sysfs mounted
			# Only mount it if not mounted already
			if [ ! -d /target/sys/devices ]; then
				mount -t linsysfs sysfs /target/sys
			fi
		;;
	esac

	mountpoints > /tmp/mount.post

	update_mtab

	# Try to enable proxy when using HTTP.
	# What about using ftp_proxy for FTP sources?
	RET=$(debconf-get mirror/protocol || true)
	if [ "$RET" = "http" ]; then
		RET=$(debconf-get mirror/http/proxy || true)
		if [ "$RET" ]; then
			http_proxy="$RET"
			export http_proxy
		fi
	fi

	# Pass debconf priority through.
	DEBIAN_PRIORITY=$(debconf-get debconf/priority || true)
	export DEBIAN_PRIORITY

	LANG=${IT_LANG_OVERRIDE:-$(debconf-get debian-installer/locale || true)}
	export LANG
	export PERL_BADLANG=0

	# Unset variables that would make scripts in the target think
	# that debconf is already running there.
	unset DEBIAN_HAS_FRONTEND
	unset DEBIAN_FRONTEND
	unset DEBCONF_FRONTEND
	unset DEBCONF_REDIR
	# Avoid debconf mailing notes.
	DEBCONF_ADMIN_EMAIL=""
	export DEBCONF_ADMIN_EMAIL
	# Avoid apt-listchanges doing anything.
	APT_LISTCHANGES_FRONTEND=none
	export APT_LISTCHANGES_FRONTEND
	# Sometimes sudo may need to be removed (e.g. when installing
	# sudo-ldap).  There's no situation in which doing this during d-i
	# is a problem, so unconditionally override the guard in sudo.prerm.
	SUDO_FORCE_REMOVE=yes
	export SUDO_FORCE_REMOVE

	return 0
}

chroot_cleanup () {
	rm -f /target/usr/sbin/policy-rc.d
	undivert /sbin/start-stop-daemon
	if [ -x /target/sbin/initctl.REAL ]; then
		undivert /sbin/initctl
	fi

	# Undo the mounts done by the packages during installation.
	# Reverse sorting to umount the deepest mount points first.
	# Items with count of 1 are new.
	for dir in $( (cat /tmp/mount.pre /tmp/mount.pre; mountpoints ) | \
		     sort -r | uniq -c | grep "^[[:space:]]*1[[:space:]]" | \
		     sed "s/^[[:space:]]*[0-9][[:space:]]//"); do
		if ! umount $dir; then
			logger -t $0 "warning: Unable to umount '$dir'"
		fi
	done
	rm -f /tmp/mount.pre /tmp/mount.post

	rm -f /var/run/chroot-setup.lock
}

# Variant of chroot_cleanup that only cleans up chroot_setup's mounts.
chroot_cleanup_localmounts () {
	rm -f /target/usr/sbin/policy-rc.d
	undivert /sbin/start-stop-daemon
	if [ -x /target/sbin/initctl.REAL ]; then
		undivert /sbin/initctl
	fi

	# Undo the mounts done by the packages during installation.
	# Reverse sorting to umount the deepest mount points first.
	# Items with count of 1 are new.
	for dir in $( (cat /tmp/mount.pre /tmp/mount.pre /tmp/mount.post ) | \
		     sort -r | uniq -c | grep "^[[:space:]]*1[[:space:]]" | \
		     sed "s/^[[:space:]]*[0-9][[:space:]]//"); do
		if ! umount $dir; then
			logger -t $0 "warning: Unable to umount '$dir'"
		fi
	done
	rm -f /tmp/mount.pre /tmp/mount.post

	rm -f /var/run/chroot-setup.lock
}