add script

Signed-off-by: Mattéo Rossillol‑‑Laruelle <beatussum@protonmail.com>

Makefile

@@ -0,0 +1,15 @@
+PREFIX  ?= /usr/local
+DESTDIR ?=
+
+INITDDIR ?= $(DESDIR)$(PREFIX)/etc/init.d
+
+INSTALL ?= install -D -m755
+RM      ?= rm -f
+
+.PHONY: install
+install: 
+	$(INSTALL) backlight-restorer $(INITDDIR)/backlight-restorer
+
+.PHONY: uninstall
+uninstall: 
+	$(RM) $(INITDDIR)/backlight-restorer

backlight-restorer

@@ -0,0 +1,51 @@
+#!/sbin/openrc-run
+
+# Copyright (C) 2019 Mattéo Rossillol‑‑Laruelle <beatussum@protonmail.com>
+#
+# This program is free software:  you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published  by
+# the Free Software Foundation, either version 3 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY;  without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE.  See  the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program. If not, see <https://www.gnu.org/licenses/>.
+
+
+description="An OpenRC service for restoring the last brightness level on reboot"
+
+start() {
+	ebegin "Restoring the screen brightness"
+
+	for card in $(basename /sys/class/backlight/*); do
+		local -r blight=$(cat "/var/cache/backlight/${card}")
+		if [ ${blight} -ne 0 ]; then
+			echo ${blight} > "/sys/class/backlight/${card}/brightness"
+		fi
+
+		sts=$?
+		test ${sts} -ne 0 || break
+	done
+
+	eend ${sts} "Cannot restore the brightness of ${card}"
+}
+
+stop() {
+	ebegin "Saving the screen brightness"
+
+	checkpath -D -o "root:root" /var/cache/backlight
+
+	for card in $(basename /sys/class/backlight/*); do
+		cp "/sys/class/backlight/${card}/brightness" \
+			"/var/cache/backlight/${card}"
+
+		sts=$?
+		test ${sts} -ne 0 || break
+	done
+
+	eend ${sts} "Cannot save the brightness of ${card}"
+}