ifupdown-ng/executor-scripts/linux/wifi
Zola e978d1a42c Fix a bug in the wifi executor script
When stopping wpa_supplicant, the code is supposed to check if a file named $PIDFILE exists and kill the process listed inside. Instead it was checking if a directory named $PIDFILE exists and because this was never the case, killing of the wpa_supplicant process would always silently fail.

This would, after a few invocations of the ifup command, leave the system with large number of running wpa_supplicant processes, all trying to take control of the same interface.
2021-11-25 22:44:19 -06:00

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#!/bin/sh
# Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# This software is provided 'as is' and without any warranty, express or
# implied. In no event shall the authors be liable for any damages arising
# from the use of this software.
#
# Manage wifi connections using wpa_supplicant.
#
# Vocabulary:
# wifi-ssid - The SSID name to connect to.
# wifi-psk - The pre-shared key to use.
# wifi-config - A path to a wpa_supplicant config file, for special configs.
#
# If wifi-config is not set, wifi-ssid and wifi-psk are required, and a config
# will be generated as /run/wpa_supplicant.$IFACE.conf.
#
# The wpa_supplicant PID is stored in /run/wpa_supplicant.$IFACE.pid.
die() {
printf "ERROR: %s\n" "$1" >&2
exit 1
}
[ -z "$IFACE" ] && die "IFACE not set"
[ -z "$PHASE" ] && die "PHASE not set"
PIDFILE="/run/wpa_supplicant.$IFACE.pid"
# Do not allow mixing wifi-config-path and wifi-ssid/wifi-psk.
[ -n "$IF_WIFI_CONFIG_PATH" -a -n "$IF_WIFI_SSID" ] && die "wifi-config-path cannot be used with wifi-ssid"
[ -n "$IF_WIFI_CONFIG_PATH" -a -n "$IF_WIFI_PSK" ] && die "wifi-config-path cannot be used with wifi-psk"
# Set IF_WIFI_CONFIG_PATH to the default path if not already set.
WIFI_CONFIG_PATH="$IF_WIFI_CONFIG_PATH"
[ -z "$WIFI_CONFIG_PATH" ] && WIFI_CONFIG_PATH="/run/wpa_supplicant.$IFACE.conf"
# Supplicant options.
WPA_SUPPLICANT_OPTS="-qq -B -i$IFACE -c$WIFI_CONFIG_PATH -P$PIDFILE"
# Given $IF_WIFI_SSID and $IF_WIFI_PSK, generate a config file at $WIFI_CONFIG_PATH.
generate_config() {
[ -z "$IF_WIFI_SSID" ] && die "wifi-ssid not set"
[ -z "$IF_WIFI_PSK" ] && die "wifi-psk not set"
# We use a pipeline here to avoid leaking PSK into the process name.
(echo $IF_WIFI_PSK | /sbin/wpa_passphrase $IF_WIFI_SSID) >$WIFI_CONFIG_PATH
[ ! -e "$WIFI_CONFIG_PATH" ] && die "failed to write temporary config: $WIFI_CONFIG_PATH"
}
# Should we use the supplicant?
use_supplicant() {
[ -n "$IF_WIFI_CONFIG_PATH" ] && return 0
[ -n "$IF_WIFI_PSK" ] && return 0
return 1
}
# Either start a supplicant process for $IFACE, or use iwconfig to trigger an
# association attempt.
start() {
if use_supplicant; then
# If there is no config file located at $WIFI_CONFIG_PATH, generate one.
[ ! -e "$WIFI_CONFIG_PATH" ] && generate_config
/sbin/wpa_supplicant $WPA_SUPPLICANT_OPTS
else
/usr/sbin/iwconfig $IFACE essid -- "$IF_WIFI_SSID" ap any
fi
}
# Stop wpa_supplicant safely
stop_wpa_supplicant() {
# Remove generated config file
[ -z "$IF_WIFI_CONFIG_PATH" ] && rm -- "$WIFI_CONFIG_PATH"
# If there is no PIDFILE, there is nothing we can do
[ ! -f "$PIDFILE" ] && return
pid=$(cat "$PIDFILE")
rm -- "$PIDFILE"
# If there is no process with this PID running, we're done here
if [ ! -d "/proc/$pid/" ]; then
return
fi
# Verify that the name of the running process matches wpa_supplicant
progname_path=$(readlink -n "/proc/$pid/exe")
progname=$(basename "$progname_path")
if [ "$progname" = "wpa_supplicant" ]; then
kill -9 $pid 2>/dev/null
fi
}
# Either stop the supplicant process for $IFACE, or use iwconfig to dissociate
# from the current SSID.
stop() {
if use_supplicant; then
stop_wpa_supplicant
else
/usr/sbin/iwconfig $IFACE essid any
fi
}
[ -z "$VERBOSE" ] || set -x
case "$PHASE" in
pre-up)
start
;;
post-down)
stop
;;
esac