sispmctlcups 0.0.1

#!/bin/bash
#
# sispmctlcups 0.0.1 -- CUPS backend for controlling SiS-PM devices
#
# This script saved as a CUPS backend (on Linux/FreeBSD normally in
# /usr/lib/cups/backend and on OS X in /usr/libexec/cups/backend/)
# provides an interface to GEMBIRD (m)SiS-PM devices: These are
# cheap advanced surge protectors with 1 or 4 sockets manageable
# via USB.
#
# Please compare with http://sispmctl.sourceforge.net
#
# The script creates two pseudo printers for each found SiS-PM socket.
# One to switch the socket on and the other so shut the power down.
# In case you attach two 4-port SiS-PMs to your system then 'sispmctl -s'
# would list for example:
#
# root@bananas:~# sispmctl -s
# Gembird #0
# USB information:  bus 005, device 002
# device type:      4-socket SiS-PM
# serial number:    01:01:51:45:0b
#
# Gembird #1
# USB information:  bus 003, device 002
# device type:      4-socket SiS-PM
# serial number:    01:01:51:23:cb
#
# And the backend would list 16 pseudo printers that can be used to
# switch on/off the specific socket on the SiS-PM in question. Therefore
# the script uses the serial number of each Gembird device and encodes it
# in the so called device URI. For example the first and the last socket
# of the first Gembird and the third of the second:
#
# root@bananas:~# lpinfo -v
# ...
# file sispmctlcups://01_01_51_45_0b-1-on
# file sispmctlcups://01_01_51_45_0b-1-off
# ...
# file sispmctlcups://01_01_51_45_0b-4-on
# file sispmctlcups://01_01_51_45_0b-4-off
# ...
# file sispmctlcups://01_01_51_23_cb-3-on
# file sispmctlcups://01_01_51_23_cb-3-off
#
# This means that once you're done with the setup of your printers you can
# disconnect and reconnect your Gembird USB devices in different order and
# will still be able to switch the right socket as long as you take care
# that the same devices are plugged into the same socket!
#
# Attention: Normally only root is allowed to use sispmctl on linux. So
# unless you adjust permissions as it's outlined on the sispmctl page
# http://sispmctl.sourceforge.net (eg. simply using the setuid bit:
# "chmod u+s /usr/bin/sispmctl") you won't be able to access the SiS-PM
# devices from within CUPS since the daemons are running under an
# unprivileged account like 'lp'.
#
# If you suceeded setting up the pseudo printer devices to switch on and
# off specific sockets on one of your SiS-PMs (you won't need a PPD -- just
# use 'raw' as printer type) then you could simply send empty print jobs
# to switch the sockets:
#
# root@bananas:~# echo "" | lp -d switch_on_laserjet
#
# The name of the printer queue doesn't matter. All what's important is
# the correct device URI (that contains the serial number of your device):
#
# root@bananas:~# lpstat -t | grep switch_on_laserjet
# device for switch_on_laserjet: sispmctlcups://01_01_51_45_0b-4-on
# switch_on_laserjet accepting requests since Di 25 Nov 2014 22:21:00 CET
# printer switch_on_laserjet is idle.  enabled since Di 25 Nov 2014 22:21:00 CET
#
# In case something does not work as expected, try executing sispmctl
# manually under the account the CUPS daemons run on your system (very
# important to nail down permission related problems) and temporarely
# change 'LogLevel warn' to 'LogLevel debug' in /etc/cups/cupsd.conf,
# restart cupsd and have a look into CUPS' error_log while accessing
# CUPS' administrative interfaces or printing to the pseudo printers.
#
#############################################################################
#
# You get these devices with or without surge protection / insurance:
# http://energenie.com/item.aspx?id=7556
# http://energenie.com/item.aspx?id=7025
# http://energenie.com/item.aspx?id=7415
#
# http://geizhals.at/eu/231255382 vs. http://geizhals.at/eu/a732667.html
#
#############################################################################
#
# author: Thomas Kaiser <mailto:print-to-pdf@kaiser-edv.de>
# license: GPL - http://www.gnu.org/copyleft/gpl.html
#
#############################################################################

export PATH=/usr/bin:/sbin:/bin

case $# in
    0)
        # CUPS is in 'device discovery' mode. We list our capabilities that
        # means all found SiS-PM with their serial numbers and the count of
        # sockets they provide:

        # check version
        SiSPMVersion=$(sispmctl -v 2>&1 | awk -F" " '/SiS PM Control/ {print $6}')
        case ${SiSPMVersion} in
            3.*)
                # ok
                :
                ;;
            *)
                # too old or not existing
                echo "ERROR: sispmctl is not installed, too old or not accessible" >&2
                ;;
        esac

        # generate debug output:
        echo -e "DEBUG: Output from sispmctl device discovery\nDEBUG: " >&2
        sispmctl -s 2>&1 | while read ; do
            echo "DEBUG: ${REPLY}" >&2
        done

        # define counter
        SiSPM=0

        # parse sispmctl output to get serial numbers and device types (1/4 sockets)
        sispmctl -s | awk -F": " '/^serial number:/ {print $2}' | sed 's/\ //g' | while read ; do
            SerialNumber=$(echo "${REPLY}" | sed 's/\:/_/g')
            DeviceType=$(sispmctl -s | grep -B1 "${REPLY}" | awk -F": " '/^device type:/ {print $2}')
            case ${DeviceType} in
                *1*)
                    # 1-socket mSiS-PM
                    echo -e "file sispmctlcups://${SerialNumber}-1-on \"Unknown\" \"Power on mSiS-PM #${SiSPM}/${REPLY} socket 1\"\nfile sispmctlcups://${SerialNumber}-1-off \"Unknown\" \"Switch off mSiS-PM #${SiSPM} socket 1\""
                    ;;
                *4*)
                    # 4-socket SiS-PM
                    for i in 1 2 3 4 ; do
                        echo -e "file sispmctlcups://${SerialNumber}-${i}-on \"Unknown\" \"Power on SiS-PM #${SiSPM}/${REPLY} socket ${i}\"\nfile sispmctlcups://${SerialNumber}-${i}-off \"Unknown\" \"Switch off SiS-PM #${SiSPM}/${REPLY} socket ${i}\""
                    done
                    ;;
            esac
            let SiSPM++
        done
        ;;
    5|6)
        # we have to process a switch on/off request since this is a print job
        CUPSDeviceString=$(echo "${DEVICE_URI}" | awk -F'/' '{print $3}')

        # parse device URI
        OIFS=${IFS}
        IFS="-"
        set ${CUPSDeviceString}
        SiSPMSerialnumber=$(echo ${1} | tr '_' ':')
        SiSPMSocket=${2}
        SiSPMMode=${3}
        IFS=${OIFS}
        echo "DEBUG: Switch request for ${DEVICE_URI}: SiS-PM ${SiSPMSerial} socket ${SiSPMSocket} to ${SiSPMMode}" >&2

        case ${SiSPMMode} in
            on)
                echo "DEBUG: Executing \"sispmctl -D${SiSPMSerialnumber} -o${SiSPMSocket}\"" >&2
                sispmctl -D${SiSPMSerialnumber} -o${SiSPMSocket} 2>&1 | while read ; do
                    echo "DEBUG: ${REPLY}" >&2
                done
                ;;
            off)
                echo "DEBUG: Executing \"sispmctl -D${SiSPMSerialnumber} -f${SiSPMSocket}\"" >&2
                sispmctl -D${SiSPMSerialnumber} -f${SiSPMSocket} 2>&1 | while read ; do
                    echo "DEBUG: ${REPLY}" >&2
                done
                ;;
        esac
        ;;
esac