bluetoothctl “Waiting to connect to bluetoothd…” in udev rule script

Question

I have the following udev rule:

ACTION=="add", SUBSYSTEM=="bluetooth", RUN+="/usr/local/bin/a2dp-fix-wrapper"

that fires off the following script:

PID=$(pgrep pulseaudio)
USER=$(grep -z USER= /proc/$PID/environ | sed 's/.*=//')
USER_ID=$(id -u $USER)
HOME=$(echo $(getent passwd $USER )| cut -d : -f 6)

export XDG_RUNTIME_DIR=/run/user/$USER_ID
export XAUTHORITY=$HOME/.Xauthority
export DISPLAY=:0
export PULSE_RUNTIME_PATH=$XDG_RUNTIME_DIR/pulse/

sleep 5

sudo -u $USER -E /usr/local/bin/a2dp-fix &> /udev_output.txt

and a2dp-fix is the following:

bt_device_addr=$(pacmd list-cards | grep -i 'name:.*bluez_card' | sed -E 's/.*<?bluez_card\.([A-Z0-9_]+)>?/\1/')
device_mac=$(echo $bt_device_addr | sed 's/_/:/g')

a2dp_available=$(pacmd list-cards | grep -A30 bluez | grep "A2DP Sink" | sed -E 's/.* available: ([a-z]+)\)/\1/g')

if [[ "$a2dp_available" == "no" ]]
then
    echo -e "connect $device_mac\nquit" | bluetoothctl
    sleep 5
    pacmd set-card-profile bluez_card.$bt_device_addr off
    pacmd set-card-profile bluez_card.$bt_device_addr a2dp_sink
    pacmd set-default-sink bluez_sink.$bt_device_addr.a2dp_sink
fi

After lots of meddling with env variables, I got the pacmd stuff to work. However, now the bluetoothctl part hangs with “Waiting to connect to bluetoothd…”. This works just fine if I invoke it manually from shell with sudo /usr/local/bin/a2dp-fix-wrapper but not when udev kicks it off. I imagine it must be some sort of env variable that prevents bluetoothctl from finding the running bluetoothd instance.

Anyone have any thoughts?

Answer 1

After a long time, I decided to give this another try and finally got it to do what I want using dbus instead of bluetoothctl.

I tried a few things that didn't work. Instead of echo -e "connect $device_mac\nquit" | bluetoothctl I tried:

coproc bluetoothctl
echo -e "select E4:B3:18:48:43:D2\nconnect $device_mac\nquit" >&${COPROC[1]}
output=$(cat <&${COPROC[0]})
echo $output

I also tried:

hcitool cc $device_mac

And I also tried a couple of python scripts, but ultimately, using dbus-send solved my problem.

My scripts are as follows:

/etc/udev/rules.d/80-bt-headset.rules

ACTION=="add", SUBSYSTEM=="bluetooth", RUN+="/usr/local/bin/a2dp-fix-wrapper"

/usr/local/bin/a2dp-fix-wrapper

#!/bin/bash

for PID in $(pgrep pulseaudio); do
    USER=$(grep -z USER= /proc/$PID/environ | sed 's/.*=//' | tr -d '\0')
    USER_ID=$(id -u $USER)
    HOME=$(echo $(getent passwd $USER )| cut -d : -f 6)

    export XDG_RUNTIME_DIR=/run/user/$USER_ID
    export XAUTHORITY=$HOME/.Xauthority
    export DISPLAY=:0

    sleep 5
    if [[ ! -z $USER ]]; then
        sudo -u $USER -E /usr/local/bin/a2dp-fix
    fi
done

/usr/local/bin/a2dp-fix

#!/bin/bash

bt_device_addr=$(pacmd list-cards | grep -i 'name:.*bluez_card' | sed -E 's/.*<?bluez_card\.([A-Z0-9_]+)>?/\1/')
device_mac=$(echo $bt_device_addr | sed 's/_/:/g')

a2dp_available=$(pacmd list-cards | grep -A30 bluez | grep "A2DP Sink" | sed -E 's/.* available: ([a-z]+)\)/\1/g')

if [[ "$a2dp_available" == "no" ]]
then
    dbus-send --system --dest=org.bluez --print-reply /org/bluez/hci0/dev_$bt_device_addr org.bluez.Device1.Connect

    pacmd set-card-profile bluez_card.$bt_device_addr off
    pacmd set-card-profile bluez_card.$bt_device_addr a2dp_sink
    pacmd set-default-sink bluez_sink.$bt_device_addr.a2dp_sink
fi

Now my bluetooth headset always connects using the a2dp sink :-D

Big thanks to this post for the inspiration.