Customizing Printing Services (Task Map)

Task	Description	For Instructions
Add a terminfo entry of an unsupported printer.	Add an entry to the terminfo database to initialize an unsupported printer and establish required settings.	How to Add a terminfo Entry for an Unsupported Printer
Set up a custom printer interface program.	You can furnish a custom printer interface program if you have a printer that is not supported by the standard printer interface program.	How to Set Up a Custom Printer Interface Program
Adjust the printer port characteristics.	Make printer port characteristics the are set by the LP print service compatible with the printer communication settings.	How to Adjust the Printer Port Characteristics

Adjusting Printer Port Characteristics

The printer port characteristics set by the LP print service must be compatible with the printer communication settings. If the default printer port settings provided by the LP print service do not work with a printer, refer to the printer manual from the manufacturer to determine what settings the printer requires from the LP print service. Use the stty command to set and display printer communication settings.

The following table shows the default stty settings that are used by the LP print service.

Table 7-1 Default stty Settings Used by the LP Print Service

Option	Description
-9600	Sets baud to 9600
-cs8	Sets 8-bit bytes
-cstopb	Sends one stop bit per byte
-parity	Does not generate parity
-ixon	Enables XON/XOFF (also known as START/STOP or DC1/DC3)
-opost	Does “output post-processing” using all the settings that follow in this table
-olcuc	Do not map lowercase to uppercase
-onlcr	Changes linefeed to carriage return/linefeed
-ocrnl	Does not change carriage returns into linefeeds
-onocr	Outputs carriage returns even at column 0
-n10	Provides no delay after linefeeds
-cr0	Provides no delay after carriage returns
-tab0	Provides no delay after tabs
-bs0	Provides no delay after backspace characters
-vt0	Provides no delay after vertical tabs
-ff0	Provides no delay after form feeds

How to Adjust the Printer Port Characteristics

1. Log in as superuser, lp, or assume an equivalent role on the print server.
2. Adjust the printer port characteristics.

   # lpadmin -p printer-name -o "stty=options"

   -p

   Specifies the name of the printer for which you are adjusting the port characteristics.

   -o “stty=options”

   Sets the port characteristic (stty option) specified by options. You can change more than one stty option setting with this command. Enclose each option in single quotation marks, and use a space to separate the options. For a complete list of options, see thestty(1) man page. Table 7-1 shows the default stty settings used by the LP print service.

3. Verify that the printer port characteristics have been changed.

   # lpstat -p printer-name -l

Example 7-1 Adjusting the Printer Port Characteristics

This example shows how to set the port characteristics for the printer luna. The parenb option enables parity checking/generation. The parodd option sets odd parity generation. The cs7 option sets the character size to 7 bits.

# lpadmin -p luna -o "stty='parenb parodd cs7'"

Example 7-2 Setting the Terminal Baud Rate

This example shows how to set the terminal baud rate to 19200 for the printer venus.

# lpadmin -p venus -o "stty=19200"

Adding a terminfo Entry for an Unsupported Printer

The LP print service uses an interface program and the terminfo database to initialize each printer and establish the following:

• Selected page size

• Character pitch

• Line pitch

• Character set

Each printer is identified in the terminfo database with a short name. The short name required by the terminfo database is identical to the name used to set the TERM shell variable. This name is also the printer type that you specify when setting up a printer. For example, the entries for different types of PostScript printers are in the /usr/share/lib/terminfo/P directory. The default entries provided with the SunOS software release are PS (for PostScript) and PSR (for PostScript Reverse).

If you cannot find a terminfo entry for your printer, you still might be able to use the printer with the LP print service without the automatic selection of page size, pitch, and character sets. However, you might have trouble keeping the printer set in the correct modes for each print request.

If no terminfo entry exists for your type of printer and you want to keep the printer set in the correct modes, you can do one of the following:

• Customize the interface program used with the printer.

• Add an entry to the terminfo database.

A terminal or printer entry in the terminfo database contains and defines hundreds of items. The LP print service, however, uses fewer than 50 of these items. The following table lists the required terminfo items for a printer.

Table 7-2 Required terminfo Items for a Printer (Booleans)

Item		Description
Booleans:
	cpix	Changing character pitch changes resolution
	daisy	Printer requires an operator to change character set
	lpix	Changing line pitch changes resolution

Table 7-3 Required terminfo Items for a Printer (Numbers)

Item		Description
Numbers:
	bufsx	Number of bytes buffered before printing
	cols	Number of columns in a line
	cps	Average print rate in characters per second
	it	Tabs initially every n spaces
	lines	Number of lines on a page
	orc	Horizontal resolution, in units per character
	orhi	Horizontal resolution, in units per inch
	orl	Vertical resolution, in units per line
	orvi	Vertical resolution, in units per inch

Table 7-4 Required terminfo Items for a Printer (Strings)

Item		Description
Strings:
	chr	Changes horizontal resolution
	cpi	Changes number of characters per inch
	cr	Carriage return
	csnm	List of character set names
	cudl	Moves carriage down one line
	cud	Moves carriage down n lines
	cuf	Moves carriage to the right n columns
	cvr	Changes vertical resolution
	ff	Ejects page
	hpa	Horizontal position absolute
	ht	Tabs to next 8-space tab stop
	if	Is the name of initialization file
	iprog	Is the path name of initialization program
	is1	Is a printer initialization string
	is2	Is a printer initialization string
	is3	Is a printer initialization string
	lpi	Changes number of lines per inch
	mgc	Clears all margins (top, bottom, and sides)
	rep	Repeats a character n times
	rwidm	Disables double-wide printing
	scs	Selects character set
	scsd	Starts definition of a character set
	slines	Set page length to n lines per page
	smgl	Sets left margin at current column
	smglp	Set left margin
	smgr	Sets right margin at current column
	smgrp	Sets right margin
	smglr	Sets both left and right margins
	msgt	Sets top margin at current line
	smgtp	Sets top margin
	smgb	Sets bottom margin at current line
	smgbp	Sets bottom margin
	smgtb	Sets both top and bottom margins
	swidm	Enables double-wide printing
	vpa	Sets vertical position to absolute

How to Add a terminfo Entry for an Unsupported Printer

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Note - Before you create a terminfo entry for a printer, make sure that none of the existing terminfo entries will support the printer. To do so, try to set up the printer with an entry for a similar printer, if a similar printer exists.

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1. Log in as superuser, lp, or assume an equivalent role on the print server.
2. Determine a terminfo entry name for the printer.

   The directories in the /usr/share/lib/terminfo directory contain all the valid terminfo entries. Use these entries as a guide for choosing a name for the printer.

3. Create a terminfo entry file for the printer.

   Table 7-2 shows the items you must define in the terminfo entry to add a new printer to the LP print service. For more details about the structure of the terminfo database, see the terminfo(4) man page.

   To help you start writing a new terminfo entry, use the infocmp command to save an existing terminfo entry to a file. This command is helpful if there is a terminfo entry that is similar to entry you want to create. For example, the following command saves the ps entry to the ps_cust file, which will become the new terminfo entry.

   infocmp ps > ps_cust

4. Compile the terminfo entry file into the terminfo database.

   # tic terminfo_entry

   where terminfo-entry variable is the terminfo entry file you created.

5. Check for the new terminfo entry file in the /usr/share/lib/terminfo directory.

Customizing the Printer Interface Program

If you have a printer that is not supported by the standard printer interface program, you can furnish your own printer interface program. You can copy the standard program and then tell the LP print service to use it for a specified printer. First, you need to understand what is in the standard program. The following section describes the standard program.

A printer interface program should perform the following tasks:

• Initialize the printer port, if necessary. The standard printer interface program uses the stty command to initialize the printer port.

• Initialize the printer hardware. The standard printer interface program receives the control sequences from the terminfo database and the TERM shell variable.

• Print a banner page, if necessary.

• Print the number of copies that are specified by the print request.

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Caution - If you have a printer interface program from a release of UNIX System V prior to release 3.2, it will probably work with the Solaris Express, SunOS 5.10, or compatible LP print service. However, several -o options have been standardized in the Solaris Express, SunOS 5.10, or compatible LP print service. These options will be passed to every printer interface program. These options might interfere with similarly named options used by the old interface.

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The LP print service, not a printer interface program, is responsible for opening the printer port. The printer port is given to the printer interface program as standard output. In addition, the printer is identified as the “controlling terminal” for the printer interface program so that a “hang-up” of the port causes a SIGHUP signal to be sent to the printer interface program.

The Standard Printer Interface Program

The standard (model) printer interface program is /usr/lib/lp/model/standard. This program is used by the LP print service to set the printing defaults shown in the following table.

Table 7-5 Default Printer Port Characteristics

Characteristic	Default Setting
Default filter	None
Character pitch	None
Line pitch	None
Page width	None
Page length	None
Character set	None
stty options	9600 cs8 -cstopb -parenb -parodd ixon -ixany opost -olcuc onlcr -ocrnl -onocr -onlret -ofill nl0 cr0 tab0 bs0 vt0 ff0
Exit code	0

Customizing stty Modes

If you need to change the terminal characteristics, such as baud rate or output options, find the section of the standard printer interface program that begins with the following comment:

## Initialize the printer port

For more information, see the Adjusting Printer Port Characteristics.

Exit Codes

When printing is complete, your interface program should exit with a code that shows the status of the print job. The exit code is the last entry in the printer interface program.

The following table shows the exit codes and how they are interpreted by the LP print service.

Table 7-6 Printer Interface Program Exit Codes

Exit Code	Meaning to the LP Print Service
0	The print request has been successfully completed. If a printer fault occurred, it has been cleared.
1 to 127	A problem was encountered when printing a request. For example, there were too many nonprintable characters or the request exceeds the printer's capabilities. The LP print service notifies the person who submitted the request that an error occurred when printing it. This error does not affect future print requests. If a printer fault has occurred, it has been cleared.
128	This code is reserved for use by the LP print service. Interface programs must not exit with this code.
129	A printer fault was encountered when printing the request. This fault does affect future print requests. If the fault recovery for the printer directs the LP print service to wait for the administrator to correct the problem, the LP print service disables the printer. If the fault recovery is to continue printing, the LP print service does not disable the printer. However, the print service will try printing again in a few minutes.
>129	These codes are reserved for use by the LP print service. Interface programs must not exit with codes in this range.

If the program exits with a code of 129, root is alerted of a printer fault. The LP print service must also reprint the request from the beginning, after the fault has been cleared. If you do not want the entire request to be reprinted, you can have the interface program send a fault message to the LP print service. (First wait for the fault to be cleared.) When the fault is cleared, the interface program can resume printing the file. When printing is finished, the printer interface program can give a 0 exit code, just as if the fault had never occurred. An added advantage of this approach: The interface program can detect when the fault is cleared automatically. Thus, the administrator does not need to re-enable the printer.

Fault Messages

You can use the lp.tell program to send fault messages to the LP print service. This program is referenced by the LPTELL shell variable in the standard printer interface code. The program takes standard input and sends it to the LP print service. The LP print service puts standard input into the message that alerts the administrator to the printer fault. If its standard input is empty, the lp.tell program does not initiate an alert. For an example of how the lp.tell program is used, examine the standard printer interface code immediately after the following comment:

# Set up the $LPTELL program to capture fault messages here

If you use the special exit code 129 or the lp.tell program, the printer interface program does not need to disable the printer itself. The interface program can disable the printer directly. However, doing so overrides the fault-alerting mechanism. Alerts are sent only if the LP print service detects that the printer has a fault, and the special exit code and the lp.tell program are its main detection tools.

If the LP print service has to interrupt printing of a file at any time, it kills the interface program with a signal TERM (trap number 15). For more information, see the kill(1) and signal(3C) man pages. If the printer interface program dies from receipt of any other signal, the LP print service assumes that future print requests are not be affected. As a result, the LP print service continues to use the printer. The LP print service notifies the user who submitted the request that the request has not been finished successfully.

When the interface is first invoked, the signals HUP, INT, QUIT, and PIPE (trap numbers 1, 2, 3, and 13) are ignored. The standard interface changes this default behavior, so that the signals are trapped at appropriate times. The standard interface interprets receipt of these signals as warnings that the printer has a problem. When the standard interface receives a signal, it issues a fault alert.

Using a Customized Printer Interface Program

You can create a customized printer interface program and use it instead of the standard printer interface program on the print server. To do so, you use the lpadmin command to register the program with the LP print service for a specific printer.

How to Set Up a Custom Printer Interface Program

1. Log in as superuser, lp, or assume an equivalent role on the print server.
2. Copy the standard printer interface program.

   # cp /var/spool/lp/model/standard  custom-interface

3. (Optional) If you already have a custom printer interface program, go to Step 5
4. Change the copy of the standard printer interface program to meet your needs.

   Refer to the description of the program in The Standard Printer Interface Program to determine what you need to change.

5. Set up the custom printer interface program for a specific printer.

   # lpadmin -p printer-name -i custom-interface

   -p

   Specifies the printer that will use the custom printer interface program.

   -i

   Is the name of the custom printer interface program.

   The custom printer interface program is registered with the LP print service, and will be used by that printer when users submit print requests.

6. Verify that the custom printer interface program has been added in the /etc/lp/printers/printer-name/configuration file.

Example 7-3 Setting Up a Custom Printer Interface Program

This example shows how to set up a custom printer interface program named custom for the printer luna.

# lpadmin -p luna -i custom

Example 7-4 Copying a Custom Printer Interface Program

This example shows how to copy a custom printer interface program from the printer venus to the printer asteroid.

# lpadmin -p asteroid -e venus