Re: [Buildroot] [PATCH 2/4] package/wpa_supplicant: adding ifupdown support

[Thomas Petazzoni via buildroot <buildroot@buildroot.org>]

Hello,

On Fri, 27 May 2022 12:33:33 +0200
Angelo Compagnucci <angelo@amarulasolutions.com> wrote:

> Actually, configuring a wifi interface as per "interfaces" man:
> 
> auto wlan0
> iface wlan0 inet dhcp
> wpa-conf /etc/wpa_supplicant.conf

Do you have a link to an interfaces manpage that documents wpa-conf?

Is this supported by the Busybox ifupdown?

> diff --git a/package/wpa_supplicant/ifupdown.sh b/package/wpa_supplicant/ifupdown.sh
> new file mode 100755
> index 0000000000..8eecf73436
> --- /dev/null
> +++ b/package/wpa_supplicant/ifupdown.sh
> @@ -0,0 +1,71 @@
> +#!/bin/sh
> +
> +# This file is executed by ifupdown in pre-up, post-up, pre-down and
> +# post-down phases of network interface configuration.
> +
> +WPA_SUP_BIN="/usr/sbin/wpa_supplicant"
> +
> +if [ -n "$IF_WPA_MAINT_DEBUG" ]; then
> +	set -x
> +fi

Where is IF_WPA_MAINT_DEBUG supposed to be defined?

> +# allow wpa_supplicant interface to be specified via wpa-iface
> +# useful for starting wpa_supplicant on one interface of a bridge
> +if [ -n "$IF_WPA_IFACE" ]; then
> +	WPA_IFACE="$IF_WPA_IFACE"
> +else
> +	WPA_IFACE="$IFACE"
> +fi

I'm curious to understand how wpa-iface ends up in IP_WPA_IFACE. I
guess I'm missing a piece of the puzzla.

> +WPA_SUP_PIDFILE="/run/wpa_supplicant.${WPA_IFACE}.pid"
> +
> +# quit if executables are not installed
> +if [ ! -x "$WPA_SUP_BIN" ]; then
> +	exit 0
> +fi

This can be removed in the context of Buildroot. We tend to not check
for the installation of executables from the same package, as it's
quite useless.

> +
> +do_start () {
> +	if [ -n "$IF_WPA_CONF" ] && [ "$IF_WPA_CONF" != "managed" ]; then
> +		if [ ! -s "$IF_WPA_CONF" ]; then
> +			echo "cannot read contents of $IF_WPA_CONF"
> +			exit 1
> +		fi
> +		WPA_SUP_CONF_CTRL_DIR=$(sed -n -e 's/[[:space:]]*#.*//g' -e 's/[[:space:]]\+.*$//g' \
> +			-e 's/^ctrl_interface=\(DIR=\)\?\(.*\)/\2/p' "$IF_WPA_CONF")
> +		if [ -n "$WPA_SUP_CONF_CTRL_DIR" ]; then
> +			WPA_SUP_CONF="-c $IF_WPA_CONF -C $WPA_SUP_CONF_CTRL_DIR"

The manpage of wpa_supplicant says:

       -C ctrl_interface
              Path to ctrl_interface socket (Per interface. Only used if -c is not).

so passing -C when -c is passed does not make sense. Or am I missing
something?

> +		else
> +			WPA_SUP_CONF="-c $IF_WPA_CONF"
> +		fi
> +	else
> +		# specify the default ctrl_interface
> +		WPA_SUP_CONF="-C $WPA_CTRL_DIR"

How is WPA_CTRL_DIR defined?

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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