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diff --git a/cups-programme.sh b/cups-programme.sh
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+#!/bin/bash
+#
+# The purpose of the backend is to print print jobs to a file and then
+# open it with a programme which the user can set in the options.
+#
+# License: GNU GPL Version 3 or later (at your choice), see http://www.gnu.org/licenses/gpl-3.0.en.html (as of 2018-05-20).
+#
+# This work is based on the 2file example backend from
+# https://community.kde.org/Printing/Developer_Tools#.272file.27_CUPS_backend_script_.28Bash_code.29,
+# retrieved on 2018-05-19, which has been licensed under GNU GPL version
+# 2 or version 3 (user's choice).
+#
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#   
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#   
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+
+# Abort on error
+set -e
+
+# The name of this backend. Do not change.
+backend_name='cups-programme'
+
+# The config file
+conffile=/etc/cups/cups-programme.conf
+
+# Timestamp
+tstamp="$(date '+%Y-%m-%d_%T%z')"
+
+# Write to stderr:
+stderr() {
+  echo "$@" 1>&2
+}
+
+### Local logging:
+log_local() {
+  echo "$@" >> "${logfile}"
+}
+
+### CUPS logging with corresponding loglevels:
+log_cups() {
+  stderr "$@"
+  log_local "$@"
+}
+
+info() {
+  firstarg="$1"
+  shift
+  log_cups "INFO: ${firstarg}" "$@"
+}
+
+notice() {
+  firstarg="$1"
+  shift
+  log_cups "NOTICE: ${firstarg}" "$@"
+}
+
+warn() {
+  firstarg="$1"
+  shift
+  log_cups "WARN: ${firstarg}" "$@"
+}
+
+error() {
+  firstarg="$1"
+  shift
+  log_cups "ERROR: ${firstarg}" "$@"
+}
+
+crit() {
+  firstarg="$1"
+  shift
+  log_cups "CRIT: ${firstarg}" "$@"
+}
+
+alert() {
+  firstarg="$1"
+  shiftlog_
+  log_cups "ALERT: ${firstarg}" "$@"
+}
+
+emerg() {
+  firstarg="$1"
+  shift
+  log_cups "EMERG: ${firstarg}" "$@"
+}
+
+
+### Reading arguments passed from CUPS:
+backend=${0}
+jobid=${1}
+cupsuser=${2}
+jobtitle=${3}
+jobcopies=${4}
+joboptions=${5}
+jobfile=${6}
+
+# Setting, and creating/clearing our logfile:
+logfile="/tmp/${backend_name}.${jobid}.log"
+echo -n '' > "${logfile}"
+# Make it world read- and writeable, in case we are run under varying user IDs.
+chmod 666 "${logfile}" 2>/dev/null || true
+
+log_local "$0 started at ${tstamp}. Our log file is: ${logfile}."
+log_local ""
+
+
+
+
+### The command we want to execute will be fetched from the environment variable 'DEVICE_URI'.
+# 
+# $DEVICE_URI format:
+# 
+#   ${backend_name}:<command>?u=<user>&g=<group>&D=<display>&<argument>&<argument>...
+# 
+# All arguments, including the 'u=<user>', 'g=<group>' and 'D=<display>', are optional.
+# Argument delimiter character is '#'.
+#
+# In '<argument>', the following replacements will be carried out:
+#   - '%s' -> "${tmpfile}" (Where we save the output from CUPS),
+#   - '%.' -> ' '
+#   - '%_' -> '-'
+#   - '%P' -> '|'
+#   - '%B' -> '\'
+#   - '%H' -> '#'
+#   - '%Q' -> '?'
+#   - '%A' -> '&'
+#   - '%%' -> '%'
+# 
+# The programme will be invoked with the specified arguments, and the
+# file name of the print job appended.
+# The print job will be a PostScript file.
+
+# Getting the command from $DEVICE_URI:
+cmd="$(echo "${DEVICE_URI}" | sed "s|^${backend_name}":'||g' | sed 's|?.*$||')"
+
+# Getting the raw options, arguments, ... from $DEVICE_URI:
+argstr="$(echo "${DEVICE_URI}" | sed -n 's|^[^?]*?\(.*\)$|\1|p')"
+
+# Creating and retrieving the name of the temporary file, for CUPS print output:
+# tmpfile="$(mktemp --tmpdir=/tmp --suffix=.ps "${backend_name}_job-${jobid}_${jobtitle}.XXXXX")"
+tmpfile="/tmp/${backend_name}_job-${jobid}_${jobtitle}.ps"
+
+# Taking the raw options, arguments, ... apart:
+IFS='&' read -r -a argv <<< "${argstr}"
+
+# Parsing the options, arguments, ...:
+cmd_args=()
+unset user
+unset group
+unset display
+# Have this as function that we will call, so that we can make use of 'shift'.
+parse_argv() {
+  log_local "Parsing options ${@@Q}."
+  while [ $# -gt 0 ]; do
+    case "$1" in
+      u=*)
+        user="${1#u=}"
+        log_local "  Parsing 'u='-option. User: '${user}'."
+      ;;
+      g=*)
+        group="${1#g=}"
+        log_local "  Parsing 'g='-option. Group: '${group}'."
+      ;;
+      D=*)
+        display="${1#D=}"
+        log_local "  Parsing 'D='-option. Display: '${display}'."
+      ;;
+      *)
+        arg=("$(echo "$1" | replace '%%' '%' '%s' "${tmpfile}" '%.' ' ' '%_' '-' '%P' '|' '%B' '\' '%H' '#' '%Q' '?' '%A' '&' )")
+        log_local "  Parsing next argument. It will be: '${arg}'."
+        cmd_args+=("${arg}")
+      ;;
+    esac
+    shift
+  done
+  log_local ""
+}
+
+parse_argv "${argv[@]}"
+
+
+### Log some debugging information
+log_local "--- Some debugging information. ---"
+log_local "We were called as:"
+log_local "  $0 $@"
+log_local ""
+log_local "Number of command line arguments passed to us: $#".
+log_local ""
+log_local "Information passed from CUPS:"
+log_local "  - backend=${backend}"
+log_local "  - jobid=${jobid}"
+log_local "  - cupsuser=${cupsuser}"
+log_local "  - jobtitle=${jobtitle}"
+log_local "  - jobcopies=${jobcopies}"
+log_local "  - joboptions=${joboptions}"
+log_local "  - jobfile=${jobfile}"
+log_local "  - DEVICE_URI=${DEVICE_URI}"
+log_local ""
+log_local "Information we extracted from \$DEVICE_URI":
+log_local "  - command=${cmd}"
+log_local "  - argstr=${argstr}"
+log_local "  - #argv=${#argv[@]}"
+log_local "  - argv=${argv[@]}"
+log_local "  - #cmd_args=${#cmd_args[@]}"
+log_local "  - cmd_args=${cmd_args[@]}"
+log_local "  - tmpfile=${tmpfile}"
+log_local ""
+log_local "Environment:"
+log_local "$(env)"
+log_local ""
+
+
+### Determine our operation mode, and handle the modes.
+case ${#} in
+     0)
+        # This case is for "backend discovery mode."
+        echo "direct ${backend_name} \"Unknown\" \"cups-programme: Print to file and open in programme. DeviceURI example: ${backend_name}:/usr/bin/gimp?u=<user>&D=:0.0&%s\". See documentation!"
+        exit 0
+     ;;
+     5)
+        # Backend needs to read from stdin if number of arguments is 5.
+        log_cups "Writing print job ${jobid} output to ${tmpfile} ..."
+        cat - > "${tmpfile}"
+        # Make it world read- and writeable, to be able to work with it as another user.
+        chmod 666 "${tmpfile}"
+        log_cups "Print job ${jobid} output written to ${tmpfile}."
+     ;;
+     6)
+        # Backend needs to read from file if number of arguments is 6.
+        log_cups "Writing print job ${jobid} output to ${tmpfile} ..."
+        cat "${6}" > "${tmpfile}"
+        # Make it world read- and writeable, to be able to work with it as another user.
+        chmod 666 "${tmpfile}"
+        log_cups "Print job ${jobid} output written to ${tmpfile}."
+     ;;
+     1|2|3|4|*)
+        # These cases are unsupported.
+        stderr "$0: Error: Called with incorrect number ($#) of arguments."
+        stderr ""
+        stderr "Usage:"
+        stderr ""
+        stderr " $0 <job-ID> <user> <jobtitle> <copies> <joboptions> [<jobfile>]"
+        stderr ""
+        stderr "OR (for backend discovery mode):"
+        stderr ""
+        stderr "  $0"
+        stderr ""
+        stderr ""
+        stderr "(Install this as CUPS backend to '/usr/lib/cups/backend/${backend_name}'.)"
+        stderr "(Read the comment in $0 to see how to set this up.)"
+        
+        error "$0 called with $# arguments. Unsupported mode. Aborting."
+        
+        exit 11
+     ;;
+esac
+
+# Postpone the logging to cups until here, because only when we reached up to here we are correctly be running as a filter.
+info "$0 started at ${tstamp}. Our log file is: ${logfile}."
+
+# Unset variables to be read from $conffile first, to be safe from cases when they hang around in the environment.
+unset su_variant
+unset askpass_cmd
+if [ -e "${conffile}" ]; then
+  log_local "Reading ${conffile}"
+  . "${conffile}" || {
+    error "$0: Error while reading ${conffile}."
+  }
+else
+  warn "$0: ${conffile} not present."
+fi
+
+
+
+su_nogroup_error() {
+  error "$0: Error: Specified to run the command under a specific group, but su_variant '${su_variant}' does not support setting the group. Aborting."
+  exit 51
+}
+
+check_su_group_root() {
+  if [ ! "$(id -u)" -eq 0 ]; then
+    error "$0: Error: Specified to run the command under a specific group, but that is only possible as root. We are run as user $(id -un)($(id -u)). Aborting."
+    exit 43
+  fi
+}
+
+check_log_su_cmd() {
+  # $1: Check for presence of the executable.
+  if ! /usr/bin/which "$1" >/dev/null 2>&1; then
+    error "$0: Error: The command '$1', specified by su_variant '${su_variant}', could not be found. Aborting."
+    exit 41
+  fi
+}
+
+check_log_cmd() {
+  # $1: Check for presence of the executable.
+  if ! /usr/bin/which "$1" >/dev/null 2>&1; then
+    error "$0: Error: The command '$1' could not be found. Aborting."
+    exit 42
+  fi
+}
+
+if [ -v user ] || [ -v group ]; then
+  if [ ! -v su_variant ]; then
+    error "$0: Error: The command should be run as a specific user or group, but 'su_variant' has not been set. Please check ${conffile}. Aborting."
+    exit 31
+  fi
+  case "${su_variant}" in
+    'su')
+      su_cmd='su'
+      su_opts="-c \"${cmd@Q} ${cmd_args[@]@Q}\""
+      if [ -v group ]; then
+        check_su_group_root
+        su_opts+=" -g ${group@Q}"
+      fi
+      if [ -v user ]; then
+        su_opts+=" ${user@Q}"
+      fi
+    ;;
+    'sudo')
+      su_cmd='sudo'
+      su_opts='-H'
+      if [ -v group ]; then
+        check_su_group_root
+        su_opts+=" -g ${group@Q}"
+      fi
+      if [ -v user ]; then
+        su_opts+=" -u ${user@Q}"
+      fi
+      su_opts+=" ${cmd@Q} ${cmd_args[@]@Q}"
+    ;;
+    'sudo-askpass')
+      if [ ! -v askpass_cmd ]; then
+        error "$0: Error: su_variant '${su_variant}' was specified, which requires the variable 'askpass_cmd' be (correctly) set in '${conffile}'. But it isn't. Aborting."
+        exit 35
+      fi
+      # export SUDO_ASKPASS=${askpass_cmd@Q}
+      su_cmd="SUDO_ASKPASS=${askpass_cmd@Q} sudo"
+      su_opts='-A -H'
+      if [ -v group ]; then
+        check_su_group_root
+        su_opts+=" -g ${group@Q}"
+      fi
+      if [ -v user ]; then
+        su_opts+=" -u ${user@Q}"
+      fi
+      su_opts+=" ${cmd@Q} ${cmd_args[@]@Q}"
+    ;;
+    'kdesu')
+      su_cmd='kdesu'
+      su_opts='-n -t'
+      if [ -v group ]; then
+        su_nogroup_error
+      fi
+      if [ -v user ]; then
+        su_opts+=" -u ${user@Q}"
+      fi
+      su_opts+=" -c ${cmd@Q} ${cmd_args[@]@Q}"
+    ;;
+    'kdesudo')
+      su_cmd='kdesudo'
+      su_opts="--nograb -n -t --comment '$0: Enter password.'"
+      if [ -v group ]; then
+        su_nogroup_error
+      fi
+      if [ -v user ]; then
+        su_opts+=" -u ${user@Q}"
+      fi
+      su_opts+=" -c ${cmd@Q} ${cmd_args[@]@Q}"
+    ;;
+    *)
+      error "$0: Error: Unsupported su_variant '${su_variant}' provided. Aborting."
+      exit 33
+    ;;
+  esac
+else
+  su_cmd='sh'
+  su_opts="-c ${cmd@Q} ${cmd_args[@]@Q}"
+fi
+
+if [ -v display ]; then
+  log_local "exporting DISPLAY=${display}"
+  export DISPLAY="${display}"
+fi
+
+notice "$0: Running 'bash -c \"${su_cmd} ${su_opts} >> ${logfile@Q} 2>&1\"'..."
+
+log_local ""
+log_local "--- Output of the command run (stdout and stderr combined): ---"
+set +e
+bash -c "${su_cmd} ${su_opts} >> ${logfile@Q} 2>&1"
+cmd_exitcode=$?
+set -e
+log_local "--- End of the output of the command run. ---"
+log_local ""
+
+if [ ${cmd_exitcode} -eq 0 ]; then
+  notice "$0: Run of 'bash -c \"${su_cmd} ${su_opts} >> ${logfile@Q} 2>&1\"' finished with exitcode ${cmd_exitcode}."
+  notice "See '${logfile}' for combined stdout and stderr."
+else
+  error "Run of 'bash -c \"${su_cmd} ${su_opts} >> ${logfile@Q} 2>&1\"' FAILED with exitcode ${cmd_exitcode}."
+  error "See '${logfile}' for combined stdout and stderr."
+fi
+
+log_local "Removing ${tmpfile}."
+rm -f "${tmpfile}"
+
+info "End of $0 run."
+
+exit "${cmd_exitcode}"