WiFi dialog: add scripts for enabling/disabling WiFi connection

debian-pkg/etc/sudoers.d/tinypilot

@@ -1,6 +1,8 @@
 tinypilot ALL=(ALL) NOPASSWD: /opt/tinypilot-privileged/scripts/change-hostname
 tinypilot ALL=(ALL) NOPASSWD: /opt/tinypilot-privileged/scripts/collect-debug-logs
 tinypilot ALL=(ALL) NOPASSWD: /opt/tinypilot-privileged/scripts/configure-janus
+tinypilot ALL=(ALL) NOPASSWD: /opt/tinypilot-privileged/scripts/disable-wifi
+tinypilot ALL=(ALL) NOPASSWD: /opt/tinypilot-privileged/scripts/enable-wifi
 tinypilot ALL=(ALL) NOPASSWD: /opt/tinypilot-privileged/scripts/read-update-log
 tinypilot ALL=(ALL) NOPASSWD: /opt/tinypilot-privileged/scripts/update
 tinypilot ALL=(ALL) NOPASSWD: /sbin/shutdown

debian-pkg/opt/tinypilot-privileged/scripts/disable-wifi

@@ -0,0 +1,45 @@
+#!/bin/bash
+#
+# Disable the WiFi network connection.
+
+# Exit on first failure.
+set -e
+
+print_help() {
+  cat <<EOF
+Usage: ${0##*/} [--help]
+Disable the WiFi network connection.
+  --help   Optional. Display this help and exit.
+EOF
+}
+
+# Parse command-line arguments.
+while (( "$#" > 0 )); do
+  case "$1" in
+    --help)
+      print_help
+      exit
+      ;;
+    *)
+      >&2 echo "Unknown flag/argument: $1"
+      >&2 echo "Use the '--help' flag for more information"
+      exit 1
+      ;;
+  esac
+done
+
+# Echo commands before executing them, by default to stderr.
+set -x
+
+# Exit on unset variable.
+set -u
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+readonly SCRIPT_DIR
+readonly CONFIG_FILE='/etc/wpa_supplicant/wpa_supplicant.conf'
+
+# Remove any existing automated configuration.
+"${SCRIPT_DIR}/strip-marker-sections" "${CONFIG_FILE}"
+
+# Effectuate changes. This will disable the WiFi connection instantly.
+rfkill block wlan

debian-pkg/opt/tinypilot-privileged/scripts/enable-wifi

@@ -0,0 +1,145 @@
+#!/bin/bash
+#
+# Enables a WiFi network connection.
+
+# Exit on first failure.
+set -e
+
+print_help() {
+  cat <<EOF
+Usage: ${0##*/} [--help] --country COUNTRY --ssid SSID [--psk PSK]
+Enables a WiFi network connection.
+  --help              Optional. Display this help and exit.
+  --country COUNTRY   A two-digit country code, as of ISO 3166-1 alpha-2.
+  --ssid SSID         The name (SSID) of the WiFi network.
+  --psk PSK           Optional. The password for authenticating. If specified,
+                      it must be 8-63 characters in length.
+
+Note: this script only stores the WiFi configuration and triggers its
+activation, but it doesn't (and cannot) verify whether the device can actually
+connect to the wireless network successfully. In that sense, enabling WiFi
+means that the device will *attempt* to connect to the wireless network, and
+otherwise fall back to the wired Ethernet connection.
+EOF
+}
+
+# Parse command-line arguments.
+while (( "$#" > 0 )); do
+  case "$1" in
+    --help)
+      print_help
+      exit
+      ;;
+    --country)
+      if (( "$#" < 2 )); then
+        shift
+        break
+      fi
+      WIFI_COUNTRY="$2"
+      shift # For flag name.
+      shift # For flag value.
+      ;;
+    --ssid)
+      if (( "$#" < 2 )); then
+        shift
+        break
+      fi
+      WIFI_SSID="$2"
+      shift # For flag name.
+      shift # For flag value.
+      ;;
+    --psk)
+      if (( "$#" < 2 )); then
+        shift
+        break
+      fi
+      WIFI_PSK="$2"
+      shift # For flag name.
+      shift # For flag value.
+      ;;
+    *)
+      >&2 echo "Unknown flag/argument: $1"
+      >&2 echo "Use the '--help' flag for more information"
+      exit 1
+      ;;
+  esac
+done
+readonly WIFI_COUNTRY
+readonly WIFI_SSID
+readonly WIFI_PSK="${WIFI_PSK:-}"
+
+if [[ -z "${WIFI_COUNTRY}" ]]; then
+  >&2 echo 'Missing argument: COUNTRY'
+  >&2 echo "Use the '--help' flag for more information"
+  exit 1
+fi
+
+# According to ISO 3166-1 alpha-2, the country code has to contain 2 letters.
+COUNTRY_LENGTH="$(echo -n "${WIFI_COUNTRY}" | wc --bytes)"
+readonly COUNTRY_LENGTH
+if (( "${COUNTRY_LENGTH}" != 2 )); then
+  >&2 echo 'Invalid argument: COUNTRY'
+  >&2 echo "Use the '--help' flag for more information"
+  exit 1
+fi
+
+if [[ -z "${WIFI_SSID}" ]]; then
+  >&2 echo 'Missing argument: SSID'
+  >&2 echo "Use the '--help' flag for more information"
+  exit 1
+fi
+
+# If a password is specified, it has to be 8-63 characters in length.
+if [[ -n "${WIFI_PSK}" ]]; then
+  PSK_LENGTH="$(echo -n "${WIFI_PSK}" | wc --bytes)"
+  readonly PSK_LENGTH
+  if (( "${PSK_LENGTH}" < 8 || "${PSK_LENGTH}" > 63 )); then
+    >&2 echo 'Invalid argument: PSK'
+    >&2 echo "Use the '--help' flag for more information"
+    exit 1
+  fi
+fi
+
+# Echo commands before executing them, by default to stderr.
+set -x
+
+# Exit on unset variable.
+set -u
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+readonly SCRIPT_DIR
+
+# Remove any existing automated configuration.
+readonly CONFIG_FILE='/etc/wpa_supplicant/wpa_supplicant.conf'
+"${SCRIPT_DIR}/strip-marker-sections" "${CONFIG_FILE}"
+
+# Write out the new configuration.
+# shellcheck source=lib/markers.sh
+. "${SCRIPT_DIR}/lib/markers.sh"
+{
+  echo "${MARKER_START}"
+  echo "country=${WIFI_COUNTRY}"
+
+  # Generate the "network" block of the config.
+  # - If a password is specified, we use the `wpa_passphrase` command. This
+  #   outputs a complete "network" block, and hashes the password instead of
+  #   storing it in clear text. Note that it still includes the original
+  #   password as comment line in the output, so we have to strip off that line
+  #   (which starts with `#psk=`)
+  # - If no password is specified, we assemble the "network" block manually. In
+  #   this case, we also have to set `key_mgmt=NONE` to denote an open network.
+  if [[ -n "${WIFI_PSK}" ]]; then
+    wpa_passphrase "${WIFI_SSID}" "${WIFI_PSK}" | sed '/^\t#psk=.*/d'
+  else
+    echo 'network={'
+    echo -e "\tssid=\"${WIFI_SSID}\""
+    echo -e '\tkey_mgmt=NONE'
+    echo '}'
+  fi
+
+  echo "${MARKER_END}"
+} >> "${CONFIG_FILE}"
+
+# Effectuate changes.
+rfkill unblock wifi
+wpa_cli -i wlan0 reconfigure

dev-scripts/mock-scripts/disable-wifi

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+# Mock version of /opt/tinypilot-privileged/scripts/disable-wifi

dev-scripts/mock-scripts/enable-wifi

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+# Mock version of /opt/tinypilot-privileged/scripts/enable-wifi