The values in the LPRng configuration file
(default: /etc/lpd.conf)
override the compile time default values for printcap options.
See the
Index To All The Configuration and Printcap Options
for an index to a complete list of configuration options.
The LPRng distribution contains a template lpd.conf file
which can be installed as
/etc/lpd.conf.
The configuration file has the following format:
# lpd.conf generated from on Wed Apr 7 07:59:48 PDT 1999
# The values in this file are the default values.
# If you modify the file, set the value to something other than the default
# For example, '# default force_localhost' means the 'force_localhost' option
# change this to 'force_localhost@' to have the opposite effect.
# Purpose: always print banner, ignore lpr -h option
# default ab@
# change ---
ab
# Purpose: query accounting server when connected
# default achk@
# Purpose: accounting at end (see also af, la, ar, as)
# default ae=jobend $H $n $P $k $b $t
# Purpose: name of accounting file (see also la, ar)
# default af=
...
The options are set exactly as for a printcap file, but do not require a leading colon (:).
To change the default value of an option, remove the comment character and edit the entry as shown in the above example.
To force the lpd server to use the new options,
use the lpc reread command.
In order to protect system security,
the
/etc/lpd.conf
and
/etc/printcap
files should be read only.
For testing purposes
when LPRng is compiled with the -DGET_ENV option
LPRng uses the value of the LPD_CONF environment variable
as the path to the lpd.conf file.
This is a security loophole,
and should not be used when running SETUID ROOT or as ROOT.
The following variables are used to set default behavior for the LPRng software, or are commonly used for configuration of LPRng operations.
Default format for printing.
Usually,
default_format=f,
but setting it to
default_format=l will cause all files spooled by lpr
to be spooled as binary files.
The default permissions to use when checking for printing or other permissions.
The default priority for a print job.
The default lpd server host.
The default directory for temporary files.
This option can be used to specify a default printer. If no value is given (default), the first printer in the printcap file will be used when no printer is specified.
You will only need to set this if LPRng can't determine your hosts domain name itself. This is usually a desperation option when DNS or some other database system is not available. The value of the $USER environment variable will be used as the return address.
Options used:
qq Insert queue name into control fileuse_queuename (alias for qq)force_queuename= Queuename to be usedThe printcap information consists of the printer name and aliases; when a job is spooled to a printer alias, it is actually spooled to the main printer entry.
The
qq
use queuename option or its
alias
use_queuename
tells
LPRng to record the queue name that a job was queued to,
and make it available to other software for processing.
The
force_queuename=...
entry forces this name to be used.
This capability has some interesting possibilities,
as shown below.
pr1_landscape|pr1_portrait|pr_raw:lp=pr@host:qq
If a job is printed using
lpr -Ppr1_landscape,
then
pr1_landscape will be recorded as the spool queue name
by the LPRng software.
Later,
when the job is processed by a filter,
the filter will be invoked with a
-Qpr1_landscape
command line option.
The filter can use the name of the queue to enable say,
landscape,
portrait,
or raw
orientations.
john|tom|frank:lp=pr@host:force_queuename=office
This printcap entry forces the queuename to be office;
this information could be used by a central routing facility to
process the information is a suitable manner.
Options used:
check_for_nonprintable LPR checks for non-printable file ml= minimum number of printable characters Normally, lpr
checks an f format file
for non-printable characters (i.e., escape characters) at the start
of the print file.
Disabling this check allows you to print executable files,
etc., which can cause extreme abuse of your printer.
Disabling can be done on a single printcap basis, or you can do this on a global basis by modifying the configuration information (see lpd.conf).
The ml value specifies the number of characters that
are to be checked.
Clearly, if it is 0, none will be checked.
Options used:
rg=Restricted group listThe rg value specifies a list of groups.
If this value is present use of a printer or operation is restricted to only
users in a particular group.
This was a wimpy attempt to do restrictions on print facilities.
The -Ppr@host option overrides this check,
unless the rg value is put in the LPRng defaults.
However,
it does provide a simple tool to have clients do some form of permissions
checking that only the lpd server could normally do.
Options used:
fx=supported formats for printingThe fx option restricts the formats supported by
a spool queue.
The lpr program uses these to check if a requested format
is supported.
By default, all formats are supported.
Options used:
safe_chars=additional safe characters for control file RFC1179 defines a simple protocol and standard for print jobs to be interchanged between print spooling systems. Unfortunately, there were some major mistakes in not specifying the exact form that text would take when placed in the control file.
In addition, there are some simple coding errors that have been made, but due to their wide distribution in major vendors software, need to be accommodated. See reverse_lpq_format for an example.
By default, LPRng will brutally convert a non-conforming RFC1179 control file into one that is acceptible to most, if not all, existing RFC1179 implementation.
In order to prevent problems with
LPRng ruthlessly purges all characters but
upper and lower case letters,
spaces, tabs, and -_.@/:()=,+-% from the control file,
replacing suspicious characters with '_'.
For some installations,
the default set of safe characters may be overly restrictive.
For example,
vintage software may generate files with # characters
in the J line of the control file.
The replacement of this character may cause other things to stop
working.
The safe_chars option allows the user to specify an additional
set of safe characters in the lpd.conf configuration file(s).
For example, safe_chars=#" would allow the
#
and
"
characters to appear in the control file.
In addition, LPRng will ruthlessly regenerate control file entries and data file names so that they are compliant with all known RFC1179 implementations.
Options:
bk Berkeley compatible control filecontrol_filter=Control file filterOne of the more serious problems is when a print spooler (LPR) program does not generate print jobs in a manner compatible with a remote system.
While LPRng performs checks for improper implementations of RFC1179, it will try to accept a job even under the most severe abuse of the protocol. However, other spoolers are not so forgiving.
Some spoolers require that the contents of the control file be in exactly the order that the original 1988 BSD LPR software generated them. While some entries can be missing, all the entries present in the file must be in an explicit order.
The bk (Berkeley LPD compatible control file) option
causes LPR and LPD to reformat the control file,
removing objectionable entries.
The control file of a job being sent to
a remote printer will have its control file entries restricted to
letters in (and the same order) as HPJCLIMWT1234.
However,
there are some very odd commercial implementations that require
more information than is present.
To assist with this,
the control_filter option can be used.
This specifies a program that will process the control file
before it is sent to a remote destination.
See
Filters for details on filter
operation,
and
Control Filters for details on the
point during job processing when the
control_filter
is used.
The control_filter program is run with the standard set of filter options.
STDIN is attached to the control file and
the STDOUT will be used as the control file value
sent to the remote host.
The
control_filter
can rewrite the control file.
The only restriction is that it cannot modify the
names or delete datafiles.
Here is a small snip of PERL code that shows how to
rewrite the control file:
# you need to get PERL to do a 'dup' call on FD 0
$status = 0;
@cf_lines = <STDIN>;
# mess about with the control file
foreach $line (@cf_lines) {
# or whatever you want
print STDOUT $line;
}
exit $status;
The exit code of the
control_filter
is used to determine whether to proceed in processing.
See
Errorcodes for details.
Options used:
mc#maximum copies The mc value specifies the maximum number of
copies of a job that can be printed on a printer using the
lpr -Knn or
lpr -#nn option.
Options used:
minfree=Size in KbytesIf this value is non-zero,
then the lpd receiving server checks to see that there is the
specified number of Kbytes of file space available before
accepting a job.
Options used:
debugging=debugging optionsfull_time full or extended time formatms_time_resolution millisecond time resolutionsyslog_device=syslog alternative deviceuse_date put date information in control fileuse_info_cache cache printcap and other informationThe LPRng software has a very powerful debugging capability. Since most printing problems occur on remote systems where it is impossible to run debuggers, and since most systems do not do core dumps of SETUID ROOT programs, the LPRng software provides a very verbose set of log file trace messages.
First,
serious errors or other information are logged using the
syslog() facilities.
If these are not present on a system,
then the messages are logged to the device specified by
syslog_device.
For client programs, the debugging options are specified on the command
line and output is directed to STDERR.
For the lpd server,
debugging commands can be specified on the command line OR as the
db=options printcap value.
Output is directed to the log file (lf option value, default log).
A typical debug entry has the format 2,network+1,database.
This sets the general
debugging level to 2, network debugging to 1 and the database debugging level
to the default. The following debugging options and levels are supported.
The full_time flag forces the logging and other information
which has timestamps to have a full (year, month, day, etc.) timestamp.
The
ms_time_resolution flag forces millisecond time resolution
in the time stamp.
The
use_date flag forces a date value to be placed in a control file
if there is none.
The use_info_cache (default ON) causes lpd
to cache printcap and configuration information.
This is desirable except when trying to change values in printcap files and
test the results.
By using use_info_cache@ in the configuration information,
you can get immediate responses.
Also, see
lpc reread
for another method.
Options used:
ipv6 use IPV6 Network facilities lockfile=lpd server lock filereport_server_as=server name for status reportsspool_dir_perms#spool directory permissions spool_file_perms#spool file permissions spread_jobs#job number spreadThese options are usually LPD specific.
For example,
the ipv6 specifies that the IPV6 protocol,
rather than IPV4 will be used.
In future versions, this may not be necessary.
The lockfile specifies the location of the
lock file used by the lpd server.
The spool_dir_perms and spool_file_perms
(default 0700 and 0600 respectively)
values are the (numeric) permissions for the spool directory and
spool files.
The spread_jobs option is obsolete.
The spread_jobs option was a desperation fix to handle
difficulties with the arrival of a large number of jobs with the same or
close job number. The LPD server would fork children,
each of whom tried to lock the job files. The spread value randomly
chose a new number in the range about the original job number.
However,
it is still preserved for legacy systems which still have problems with
file locking.
The report_server_as option allows an administrator to
masquerade a server with another name.
This could be useful if various load sharing activities are
being carried out, or if there are problems reconfiguring DNS
to cause the correct server name to be reported.
The following arguments have been provided for compatibility with legacy systems.
Options used:
allow_duplicate_args allow lpr to have duplicate arguments Some users would like duplicate LPR and LPRM command line
arguments to override earlier ones,
i.e. -
lpr -a x -a y should be equivalent to
lpr -a y
The allow_duplicate_args option
allows the various client programs to have duplicate arguments.
The last specified argument on the command line will override
previous values.
Options used:
class_in_status show class name in statusSetting the class_in_status option causes the class name rather
than priority to be displayed in the status information.
Options used:
reverse_lpq_format= reverse LPQ status format for specified remote systemsVarious Solaris and other System V implementations support an RFC1179 interface to remote printers. Unfortunately, there is a problem in that when they send a status request, the status format is reversed. That is, when LONG status format is wanted, they send SHORT, and vice versa.
The reverse_lpq_format= specifies a list of printers or IP addresses
for which the lpd server will return LONG status when SHORT is
requested,
and vice versa.
For example:
reverse_lpq_format=*.eng.com,130.192.0.0/16
will cause hosts whose Fully Qualified Domain Name (FQDN) ends in
eng.com or from subnet 130.192.0.0 to have reversed
status returned.
Options used:
return_short_status= return short LPQ status for specified remote systemsshort_status_length# short LPQ status length in linesIn order to be compatible with non-LPRng client programs,
some administrators would like lpd to return a short or brief
status to normal status queries.
The return_short_status= specifies a list of printers or IP addresses
for which the lpd server will return an abbreviated
status when LONG status is requested.
For example:
return_short_status=*.eng.com,130.192.0.0/16
short_status_length#3
will cause hosts whose Fully Qualified Domain Name (FQDN) ends in
eng.com or from subnet 130.192.0.0 to get only
3 lines of detailed status returned.
Options used:
force_lpq_status= force LPQ status format for specified remote systemsIn order to be compatible with non-LPRng client programs which are totally unpredictable, this allows the administrator to specify the format for LPQ status when requests arrrive.
The force_lpq_status= specifies a list of formats
and printers or IP addresses
for which the lpd server will return status
in the sepcified format.
The entry has the format
KEY=list;KEY=list... where
KEY is
s for short and
l for long format,
and list is a list of hosts or IP addresses.
For example:
force_lpq_status=s=pc*.eng.com,130.192.12.0/24,l=sun*.eng.com
will cause hosts whose Fully Qualified Domain Name (FQDN) matches
pc*eng.com or from subnet 130.192.12.0 to get short
status returned and hosts which match sun*.eng.com get
long status.
Options used:
ignore_requested_user_priorityprevent users from queue jumpingforce_fqdn_hostnameforce FQDN hostname in control fileSome students... um... users... will request a high priority for their job
in order to jump the queue of waiting jobs.
This option will cause the lpd server to ignore the
requested user priority.
However, the topq operation will still be effective.
Similarly, some print spoolers do not put a FQDN host name in their control file.
The force_fqdn_hostname flag will cause lpd to put a FQDN
host name in.
This will force the lpr -m (send mail to user)
option not to take an arguement, as in the BSD lpr.