if-pcl3

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#!/bin/sh
#******************************************************************************
# File:     @(#)$Id: if-pcl3,v 2.6 2001/07/07 10:05:34 Martin Rel $
# Contents: Example of a pcl3-based input filter for a Berkeley spooler (lpr)
#	    driving a PCL-3 printer
# Call:     if-pcl3 <input filter arguments>
# Author:   Martin Lottermoser, Greifswaldstrasse 28, 38124 Braunschweig,
#	    Germany. E-mail: [e-mail].
#
#******************************************************************************
#									      *
#	Copyright (C) 1998, 2000, 2001 by Martin Lottermoser		      *
#	All rights reserved						      *
#									      *
#******************************************************************************
#
# This input filter has the following interesting because unusual features:
# - If an error occurs, the user is notified by mail.
# - The filter is configurable based on the spool directory and permits in
#   particular
#   - the configuration of a "transparent" queue and
#   - the inclusion of a file with PostScript configuration commands.
# - The filter does pac(8) accounting if this is requested in the printcap file.
#
# This is not the best of all possible filters. However, all the others I've
# seen so far -- excepting those I've modified myself :-) -- lack several
# important though elementary features. Much of this is admittedly due to the
# inflexibility of the Berkeley spool system (compared to the AT&T spooler)
# but, speaking entirely subjectively, I've also often had the impression that
# the filters' authors are not as familiar with PCL, ghostscript or the
# Berkeley spooler as one should be when trying to write universally useful
# software. You should form your own opinion on this point and, if necessary,
# ruthlessly modify whatever filter you determine to use until it satisfies
# your requirements.
#
#******************************************************************************
#
# Installation
# ============
#
# printcap entry
# --------------
# Read the man page printcap(5). You should set at least 'if' (absolute path
# name of this filter), 'lp' (printer device), 'sd' (absolute path name of the
# spool directory, choose it to be queue-specific), and 'sh' (suppress header,
# should be true). Here's an example for a queue named "draft":
#
#   draft:if=/var/spool/lpd/if-pcl3:lp=/dev/lp0:sd=/var/spool/lpd/draft:sh:
#
# Other entries which are worth considering are 'af' (this must usually be a
# file named 'acct' in the spool directory, see pac(8)), 'lf', and 'mx'.
#
# You must create the spool directory if it does not exist. Usually, it should
# be owned by "daemon", group "lp", and have the file mode 770.
#
#
# Filter configuration
# --------------------
# This filter looks for a file if-pcl3.cfg in the spool directory. If it exists
# and is readable it is sourced as a shell script. The file is intended for
# setting shell variables used by this filter, redefining the two accounting
# routines, and for modifying the environment.
#
# Here follows a description of shell variables used by this filter. Note that
# you can also add other command line arguments to the gs call by setting
# GS_OPTIONS in the environment.
#
# - GS: This is normally the path name of the ghostscript executable. But if
#   the configuration file sets it to the empty string, this filter will not
#   call ghostscript but simply 'cat'. This is intended for setting up a
#   "transparent" queue which passes files through to the printer without
#   modifications.
# - INIT_TRANS: This must be empty or a parameter-less format string for the
#   'printf' command. If $GS is empty, this string will be sent before the file
#   to be printed. Use it for PCL commands under the assumption that the user
#   wishes to print a text file. In particular, this is the place to set the
#   media size to ISO A4 if that is your default paper size. My recommendation
#   for A4 and ISO 8859-1 is:
#     INIT_TRANS='\033&l26A\033(0N\033&a10L\033(s12H\033&l6.5D\033&l5E\033&l66F'
#   For US Letter size, replace the "26" near the beginning by "2".
#   Setting INIT_TRANS should have no influence on PCL files submitted to such
#   a queue because all PCL-generating programs should start their output with
#   the "Printer Reset" command (pcl3 does this) which resets all parameters to
#   their defaults.
# - RESOLUTION: This must be empty or an acceptable argument for ghostscript's
#   option '-r'. In the first case, pcl3's default resolution will be used
#   unless the document overrides it. Remember that "-r" sets also
#   "-dFIXEDRESOLUTION".
# - SUBDEVICE, COLOURMODEL, QUALITY: These must contain values for pcl3's
#   options "Subdevice", "ColourModel" and "PrintQuality".
# - PSCONFIGFILE: If this variable contains the name of an existing and
#   readable file it will be included in the call to ghostscript. This file is
#   intended to contain PostScript configuration commands, for example setting
#   the 'PageOffset' array, defining transfer functions, setting the halftone
#   screen or configuring 'InputAttributes'.
# - PAGECOUNTFILE: If pcl3 has been compiled without EPRN_NO_PAGECOUNTFILE
#   defined, it has the ability to update a page count file with the number of
#   pages printed. If this variable is non-empty (and that is the default),
#   page counting will be enabled using the file specified in the variable and
#   the count will be accumulated across jobs.
# - USE_INTERMEDIATE_FILE: When printing via ghostscript, this variable should
#   be "yes" or "no". It controls whether ghostscript's output is sent directly
#   to a printer or first to a file. Using "yes" needs substantial temporary
#   disk space but prevents wrong output in some situations and is therefore
#   the default.
#
# The defaults for these variables can be found below before the point where
# the configuration file is sourced.
#
# The two accounting functions, 'acct_start' and 'acct_stop', are always called,
# respectively, before and after the print command (cat or gs). 'acct_start'
# should return a string on standard output which will be passed as an argument
# to the later call to 'acct_stop'. The latter function should then return on
# standard output a string representation of an integer or a floating point
# number. If accounting has been enabled by an 'af' entry in the printcap file
# and the print command was successful, this value will be recorded together
# with the job owner's user name in the accounting file for later evaluation by
# 'pac'. The usual interpretation is that this value represents pages printed
# or feet of paper consumed.
#
# The default implementation of the accounting functions counts the number of
# jobs submitted for a transparent queue and the number of pages printed for a
# pcl3-based one. If PAGECOUNTFILE is empty or page counting manifestly does
# not work, the filter counts jobs also in the latter case.
#
#
#
# Restrictions
# ============
# A spool queue based on this filter processes only PostScript files correctly
# except when configured as a transparent queue in which case only text or PCL
# files should be sent. This is not a so-called "intelligent filter" which
# adapts its behaviour to the type of file received!
#
#******************************************************************************

name=`basename "$0"`

# Reset umask if 0. Otherwise an ordinary user could modify the accounting
# information if this is the first time accounting is used. This does not work
# on systems not supporting the old octal notation but is harmless there.
expr "x`umask`" : 'x00*$' > /dev/null && umask 002

# Berkeley input filters are called in the spool directory. This is used to
# locate configuration files and it usually identifies the spool queue.
spool_directory=`pwd`

#******************************************************************************

# In order to notify the user of errors occurring in the backend I'm copying
# standard error into a temporary file and mail it to the user if it is
# non-empty when the filter terminates.

errlog="${TMPDIR:-/tmp}/$$-1.tmp"
rm -f "$errlog"
notify_user=root	# This will be overwritten after we've checked the
notify_host=`uname -n`	# arguments in the call.


finish()
{
  if [ -s "$errlog" ]; then
    ${MAILX:-mailx} -s "$name: Error while printing" \
      "$notify_user"@"$notify_host" << ---
The following error occurred while running $0
in $spool_directory:

`cat $errlog`
---
    cat "$errlog" >&3	# for the log file
    rm -f "$errlog"
    exit 2
  fi
  rm -f "$errlog"
  exit 0
}


# Set up a trap for finish() on exit and SIGINT
trap finish 0 2

# Copy standard error into a file. We duplicate file descriptor 2 as 3 because
# stderr can be appended to a log file by the 'lf' field in printcap and we
# should like to be able to have both, a cumulative log file for the
# administrator and a job-specific mail message to the user.
exec 3>&2
exec 2> "$errlog"

#******************************************************************************

# Process options. Most are irrelevant for gs and this filter.
print_controls=no  # print control characters instead of interpreting them
host=		# host name of job owner
user=		# user name of job owner
length=0	# page length in lines
indentation=0	# amount of indentation in characters
width=0		# page width in characters
while getopts ch:i:l:n:w: option; do
  case "$option" in
  c)
    print_controls=yes;;
  h)
    host="$OPTARG";;
  i)
    indentation="$OPTARG";;
  l)
    length="$OPTARG";;
  n)
    user="$OPTARG";;