set serial number for network discovery at post install time

Author: mirkoCrobu

debian/arduino-app-cli/DEBIAN/postinst

@@ -4,3 +4,4 @@ chown -R arduino:arduino /home/arduino/.local/share/arduino-app-cli
 
 systemctl enable arduino-app-cli
 systemctl enable arduino-burn-bootloader
+systemctl enable arduino-avahi-serial.service

debian/arduino-app-cli/etc/systemd/system/arduino-avahi-serial.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=Configure Avahi with board serial number
+After=avahi-daemon.service
+ConditionPathExists=!/var/lib/arduino/avahi_serial_configured.flag
+
+[Service]
+Type=oneshot
+RemainAfterExit=true
+ExecStart=/usr/sbin/arduino-avahi-serial.sh
+ExecStartPost=/bin/mkdir -p /var/lib/arduino
+ExecStartPost=/bin/touch /var/lib/arduino/avahi_serial_configured.flag
+
+StandardOutput=journal
+StandardError=journal
+
+[Install]
+WantedBy=multi-user.target

debian/arduino-app-cli/usr/sbin/arduino-avahi-serial.sh

@@ -0,0 +1,46 @@
+#!/bin/sh
+#
+# Configure Avahi with the serial number.
+# This operation is non-blocking: if it fails,
+# the script will exit with success in order to 
+#not to interrupt the post-install process.
+#
+
+TARGET_FILE="/etc/avahi/services/arduino.service"
+MARKER_LINE="</service>"
+SERIAL_NUMBER_PATH="/sys/devices/soc0/serial_number"
+
+echo "Configuring Avahi with serial number for network discovery..."
+
+if [ ! -f "$SERIAL_NUMBER_PATH" ]; then
+    echo "Warning: Serial number path not found at $SERIAL_NUMBER_PATH. Skipping." >&2
+    exit 0 
+fi
+
+
+if [ ! -w "$TARGET_FILE" ]; then
+    echo "Warning: Target file $TARGET_FILE not found or not writable. Skipping." >&2
+    exit 0
+fi
+
+SERIAL_NUMBER=$(cat "$SERIAL_NUMBER_PATH")
+
+if [ -z "$SERIAL_NUMBER" ]; then
+    echo "Warning: Serial number file is empty. Skipping." >&2
+    exit 0 
+fi
+
+if grep -q "serial_number=${SERIAL_NUMBER}" "$TARGET_FILE"; then
+    echo "Serial number ($SERIAL_NUMBER) already configured. Skipping."
+    exit 0
+fi
+
+SERIAL_NUMBER_ESCAPED=$(echo "$SERIAL_NUMBER" | sed -e 's/\\/\\\\/g' -e 's/\//\\\//g' -e 's/\&/\\\&/g')
+NEW_LINE="  <txt-record>serial_number=${SERIAL_NUMBER_ESCAPED}</txt-record>"
+
+echo "Adding serial number to $TARGET_FILE..."
+
+sed -i "\#${MARKER_LINE}#i ${NEW_LINE}" "$TARGET_FILE"
+
+echo "Avahi configuration attempt finished."
+exit 0