script to conditionally sleep surface pro 3 on removal of all external usb devices, with installers to set correct udev wake rules

usbhook

#!/usr/bin/env zsh

setopt EXTENDED_GLOB NO_UNSET ERR_EXIT
typeset -g SCRIPTUSERHOME=/${(j:/:)${(s:/:)0:A}[1,2]} # TODO: probably a better way than this
typeset -g SCRIPTUSER=${${(s:/:)0:A}[2]} # TODO: probably a better way than this
typeset -g SCRIPTNAME="${${SCRIPTPATH:=$0:A}:t}"
typeset -g SCRIPTROOT="${SCRIPTPATH:h}"
typeset -g FUNCPATH=$SCRIPTROOT/functions
fpath=($FUNCPATH $fpath)
autoload $FUNCPATH/*(#q.:t)
typeset -g SCRIPTCONF="$SCRIPTUSERHOME/${XDG_CONFIG_HOME:-.config}/$SCRIPTNAME"
typeset -g SCRIPTSTATE="$SCRIPTCONF/state"
typeset -g I3INDICATORS="$SCRIPTUSERHOME/${XDG_CONFIG_HOME:-.config}/i3status"
typeset -g I3INDICATOR="$I3INDICATORS/$SCRIPTNAME"
[[ -d $SCRIPTCONF ]] || { mkdir $SCRIPTCONF; chown $SCRIPTUSER:$SCRIPTUSER $SCRIPTCONF} &>/dev/null
touch $SCRIPTSTATE
[[ -d $I3INDICATORS ]] || { mkdir $I3INDICATORS; chown $SCRIPTUSER:$SCRIPTUSER $I3INDICATORS; } &>/dev/null
alias runonce='${(P)${(U)0}:-false} && return 0 || eval typeset -g ${(U)0}=true'

# following .X11-unix line is breaking when called by root
#[[ -n $DISPLAY ]] || typeset -gx DISPLAY="$(print /tmp/.X11-unix/*(:t:s/X/:))"
typeset -gx DISPLAY=:0

[[ $(loginctl list-sessions) =~ "seat0" ]] || {
    logger -s "${SCRIPTNAME:-$0}${SCRIPTNAME:+>$0}: No X Session identified"
    exit 1
    }

if [[ $USERNAME == root ]]
then
    xauth_xauthority=/home/${${(s:/:)SCRIPTPATH}[2]}/.Xauthority
    xhost_xauthority=/var/run/gdm/auth-for-gdm*/database
    [[ -f $xhost_xauthority ]] && typeset -gx XAUTHORITY=$xhost_xauthority || {
    [[ -f $xauth_xauthority ]] && typeset -gx XAUTHORITY=$xhost_xauthority }
fi

# plug/unplug usb to internal usb hub will suspend/resume machine

# script development clues
# # udevadm info -a -p /sys/devices/pci0000:00/0000:00:14.0/usb1/1-1
# # udevadm test --action remove /sys/devices/pci0000:00/0000:00:14.0/usb1/1-1
# # udevadm monitor --environment --udev 
# # cat /usr/lib/udev/rules.d/* | grep -i remove

# ---------------------------------------------------------------------
# script values
# ---------------------------------------------------------------------

typeset -g SCRIPTNAME="${${SCRIPTPATH:=$(readlink -f $0)}:t}"
typeset -g SCRIPTROOT="${SCRIPTPATH:h}"
typeset -g SCRIPTLOCK="/var/run/$SCRIPTNAME/lock"
[[ -d ${SCRIPTLOCK:h} ]] || mkdir ${SCRIPTLOCK:h} &>/dev/null

# ---------------------------------------------------------------------
# initializers
# ---------------------------------------------------------------------

install () {

    [[ $USER == root ]] || { print "run with sudo or as root when calling $SCRIPTNAME $0"; exit 1 }

    typeset -A rules
    rules=(
    99-$SCRIPTNAME.rules    'ACTION=="remove", ENV{ID_USB_INTERFACE_NUM}=="*", RUN+="'$SCRIPTPATH' conditional_suspend $parent"'
    99-usb-hub-wakeup.rules "ACTION==\"add\", SUBSYSTEM==\"usb\", ATTRS{idVendor}==\"1d6b\", RUN+=\"/bin/sh -c \'echo enabled > /sys\$env{DEVPATH}/power/wakeup\'\""
    99-usb-hid-wakeup.rules "ACTION==\"add\", SUBSYSTEM==\"usb\", DRIVER==\"usbhid\", RUN+=\"/bin/sh -c \'echo enabled > /sys\$env{DEVPATH}/../../power/wakeup\'\", RUN+=\"/bin/sh -c \'echo enabled > /sys\$env{DEVPATH}/../power/wakeup\'\", RUN+=\"/bin/sh -c \'echo enabled > /sys\$env{DEVPATH}/power/wakeup\'\""
    )
    #99-usb-hub-wakeup.rules 'SUBSYSTEM=="usb", ATTRS{idVendor}=="1d6b", ATTRS{idProduct}=="*", RUN+="/usr/bin/echo enabled > /sys\$env{DEVPATH}/power/wakeup"'

    for rulename in ${(k)rules}
    do
        rulepath=/etc/udev/rules.d/$rulename
        rule=${rules[$rulename]}
        [[ -f $rulepath ]] && rm -f $rulepath
        print $rule > $rulepath \
            && { print "Successfully wrote udev rules file $rulepath" } \
            || { print "Failed to write udev rules file $rulepath"; exit 1 }
    done

#    service="
#    [Unit]
#    Description=Suspend system if all usb devices unplugged
#
#    [Service]
#    Type=simple
#    ExecStart=$SCRIPTPATH %I"
#
#    print -l -- "${(@)${(@f)service}##[[:space:]]#}" > /etc/systemd/system/$SCRIPTNAME\@.service \
#        && { print "Successfully wrote systemd service unit" } \
#        || { print "Failed to write systemd service unit"; exit 1 }
#
#    systemctl daemon-reload
    udevadm control --reload

}

lock () {
    print $(date +%N) > $SCRIPTLOCK || {
        notify-send "failed to make lock"
        exit 1 }
}

unlock () {
    rm $SCRIPTLOCK
}

conditional_suspend () {
    (( $(cat /sys/class/power_supply/*/online) >0 )) && exit 0 # if on ac
    # there are four builtin usb hub devices, so that's the count if we've unplugged everything
    if [[ -z ${*:-} ]] && (( ${#${(f)"$(lsusb -s 001:)"}} == 4 ))
    then
        # make sure that usb hub is set to resume and then suspend
        #if [[ "$(</sys/devices/pci0000:00/0000:00:14.0/usb1/power/wakeup)" != enabled ]]
        #then
        #    envinit
        #    notify-send "Setting usb hub to wakeup mode (check udev rule!)"
        #    print "enabled" > /sys/devices/pci0000:00/0000:00:14.0/usb1/power/wakeup || {
        #    notify-send "Failed!"; exit 1 }
        #fi

        # disable all except hub, hub parents, hub descendants
        for w in /sys/devices/**/wakeup; do print disabled > $w; done
        device=/sys/devices/pci0000:00/0000:00:14.0/usb1
        while [[ -n $device && $device != "/" ]]
        do
            [[ -f $device/power/wakeup ]] && print enabled > $device/power/wakeup
        device=${device:h}
        done

        if (( ${#${(f)"$(lsusb -s 001:)"}} <= 4 )) \
        && (( $(cat /sys/class/power_supply/*/online) == 0 )) \
        && [[ ! -f $SCRIPTLOCK ]]
        then

            lock
            systemctl suspend
            unlock

        elif [[ -f $SCRIPTLOCK ]]
        then

            # script lock present, skip suspend
            :

        elif (( ${#${(f)"$(lsusb -s 001:)"}} > 4 ))
        then

            # more than 4 devices attached, skip suspend
            :

        elif (( $(cat /sys/class/power_supply/*/online) == 1 ))
        then

            # still plugged in to power, skip suspend
            :

        else

            notify-send --urgency=critical "$SCRIPTNAME: Unknown state encountered in $0"

        fi
    fi
}

${*:-}

The above is an ugly hack and messy code. I look forward to throwing it away soon.

did you ever come up with a better solution than this?