Pure shell update package installer for Android

update-package.sh

#!/bin/bash

set -e

UPDATE_PKG=$1

if [ "$UPDATE_PKG" == "" ]; then
	echo "Usage: $0 <update package>"
	echo
	exit 1
fi

cat >/tmp/android-update-shim.sh <<'END'
#!/bin/bash

set -e

UPDATE_PKG=$1
UPDATE_BINARY=META-INF/com/google/android/update-binary
FIFO=/tmp/update-fifo

echo "Installing package $UPDATE_PKG..."
echo "  (Note that this trampoline DOES NOT support signature verification)"

if ! unzip -qo $UPDATE_PKG $UPDATE_BINARY -d /tmp; then
	echo "Not an update package." >&2
	exit 1
fi

mkfifo $FIFO
exec 3<>$FIFO
rm -f $FIFO

echo "Launching update-binary..."

TRAMPOLINE=$$

updater() {
	# update-binary <API version> <command fd> <update zip>
	chmod +x /tmp/$UPDATE_BINARY

	if /tmp/$UPDATE_BINARY 3 3 $UPDATE_PKG 1>/dev/null; then
		echo "Update was successful."
	else
		echo "Update has FAILED."
	fi

	rm -f /tmp/$UPDATE_BINARY
	kill $TRAMPOLINE
}

updater &

trap "exit" SIGTERM

while read line <&3; do
	line="${line} "
	cmd=${line%% *}
	args=${line#* }

	case $cmd in
	ui_print)
		if [ "$args" != "" ]; then
			echo "$args"
		fi
	esac
done
END

echo "Pushing trampoline..."

adb push /tmp/android-update-shim.sh /tmp/update-shim.sh
rm /tmp/android-update-shim.sh

echo "Repacking update..."

mkdir /tmp/android-update
unzip -q "$UPDATE_PKG" -d /tmp/android-update

(cd /tmp/android-update;
	zip -q -r ../android-update-repacked.zip *)

echo "Pushing update..."

adb push /tmp/android-update-repacked.zip /tmp/update.zip

rm -rf /tmp/android-update /tmp/android-update-repacked.zip

echo "Launching trampoline..."

adb shell '/sbin/ash /tmp/update-shim.sh /tmp/update.zip'