Docbook XML conversion: manpages

[ira/wip.git] / docs / docbook / projdoc / printer_driver2.sgml

<chapter id="printing">

<chapterinfo>
        &author.jerry;
        <author>
                <firstname>Patrick</firstname><surname>Powell</surname>
                <affiliation>
                        <address><email>papowell@lprng.org</email></address>
                </affiliation>
        </author>
        <pubdate> (3 May 2001) </pubdate>
</chapterinfo>

<title>Printing Support</title>

<sect1>
<title>Introduction</title>
        
<para>Beginning with the 2.2.0 release, Samba supports 
the native Windows NT printing mechanisms implemented via 
MS-RPC (i.e. the SPOOLSS named pipe).  Previous versions of 
Samba only supported LanMan printing calls.</para>

<para>The additional functionality provided by the new 
SPOOLSS support includes:</para>
        
<itemizedlist>
        <listitem><para>Support for downloading printer driver 
        files to Windows 95/98/NT/2000 clients upon demand.
        </para></listitem>
        
        <listitem><para>Uploading of printer drivers via the 
        Windows NT Add Printer Wizard (APW) or the 
        Imprints tool set (refer to <ulink 
        url="http://imprints.sourceforge.net">http://imprints.sourceforge.net</ulink>). 
        </para></listitem>
                
        <listitem><para>Support for the native MS-RPC printing 
        calls such as StartDocPrinter, EnumJobs(), etc...  (See 
        the MSDN documentation at <ulink 
        url="http://msdn.microsoft.com/">http://msdn.microsoft.com/</ulink> 
        for more information on the Win32 printing API)
        </para></listitem>
                
        <listitem><para>Support for NT Access Control Lists (ACL) 
        on printer objects</para></listitem>
        
        <listitem><para>Improved support for printer queue manipulation 
        through the use of an internal databases for spooled job 
        information</para></listitem>
</itemizedlist>

<para>
There has been some initial confusion about what all this means
and whether or not it is a requirement for printer drivers to be 
installed on a Samba host in order to support printing from Windows 
clients. As a side note, Samba does not use these drivers in any way to process 
spooled files.  They are utilized entirely by the clients.
</para>

<para>
The following MS KB article, may be of some help if you are dealing with
Windows 2000 clients:  <emphasis>How to Add Printers with No User 
Interaction in Windows 2000</emphasis>
</para>

<para>
<ulink url="http://support.microsoft.com/support/kb/articles/Q189/1/05.ASP">http://support.microsoft.com/support/kb/articles/Q189/1/05.ASP</ulink>
</para>

</sect1>


<sect1>
<title>Configuration</title>

<warning>
<title>[print$] vs. [printer$]</title>

<para>
Previous versions of Samba recommended using a share named [printer$].  
This name was taken from the printer$ service created by Windows 9x 
clients when a printer was shared.  Windows 9x printer servers always have 
a printer$ service which provides read-only access via no 
password in order to support printer driver downloads.
</para>
        
<para>
However, the initial implementation allowed for a 
parameter named <parameter>printer driver location</parameter> 
to be used on a per share basis to specify the location of 
the driver files associated with that printer.  Another 
parameter named <parameter>printer driver</parameter> provided 
a means of defining the printer driver name to be sent to 
the client.
</para>

</warning>
 
<sect2>
<title>Creating [print$]</title>        

<para>
In order to support the uploading of printer driver 
files, you must first configure a file share named [print$].  
The name of this share is hard coded in Samba's internals so 
the name is very important (print$ is the service used by 
Windows NT print servers to provide support for printer driver 
download).
</para>

<para>You should modify the server's smb.conf file to add the global
parameters and to create the 
following file share (of course, some of the parameter values,
such as 'path' are arbitrary and should be replaced with
appropriate values for your site):</para>

<para><programlisting>
[global]
    ; members of the ntadmin group should be able
    ; to add drivers and set printer properties
    ; root is implicitly a 'printer admin'
    printer admin = @ntadmin

[print$]
    path = /usr/local/samba/printers
    guest ok = yes
    browseable = yes
    read only = yes
    ; since this share is configured as read only, then we need
    ; a 'write list'.  Check the file system permissions to make
    ; sure this account can copy files to the share.  If this
    ; is setup to a non-root account, then it should also exist
    ; as a 'printer admin'
    write list = @ntadmin,root
</programlisting></para>
        
<para>The <ulink url="smb.conf.5.html#WRITELIST"><parameter>
write list</parameter></ulink> is used to allow administrative 
level user accounts to have write access in order to update files 
on the share.  See the <ulink url="smb.conf.5.html">smb.conf(5) 
man page</ulink> for more information on configuring file shares.</para>
        
<para>The requirement for <ulink url="smb.conf.5.html#GUESTOK"><command>guest 
ok = yes</command></ulink> depends upon how your
site is configured.  If users will be guaranteed to have 
an account on the Samba host, then this is a non-issue.</para>

<note>  
<title>Author's Note</title>

<para>
The non-issue is that if all your Windows NT users are guaranteed to be 
authenticated by the Samba server (such as a domain member server and the NT 
user has already been validated by the Domain Controller in 
order to logon to the Windows NT console), then guest access 
is not necessary.  Of course, in a workgroup environment where 
you just want to be able to print without worrying about 
silly accounts and security, then configure the share for 
guest access.  You'll probably want to add <ulink 
url="smb.conf.5.html#MAPTOGUEST"><command>map to guest = Bad User
</command></ulink> in the [global] section as well.  Make sure 
you understand what this parameter does before using it 
though. --jerry
</para>
</note>

<para>In order for a Windows NT print server to support 
the downloading of driver files by multiple client architectures,
it must create subdirectories within the [print$] service
which correspond to each of the supported client architectures.
Samba follows this model as well.</para>

<para>Next create the directory tree below the [print$] share 
for each architecture you wish to support.</para>

<para><computeroutput>
[print$]-----
        |-W32X86           ; "Windows NT x86"
        |-WIN40            ; "Windows 95/98"
        |-W32ALPHA         ; "Windows NT Alpha_AXP"
        |-W32MIPS          ; "Windows NT R4000"
        |-W32PPC           ; "Windows NT PowerPC"
</computeroutput></para>

<warning>
<title>ATTENTION!  REQUIRED PERMISSIONS</title>
        
<para>
In order to currently add a new driver to you Samba host, 
one of two conditions must hold true:
</para>
                
<itemizedlist>
        <listitem><para>The account used to connect to the Samba host 
        must have a uid of 0 (i.e. a root account)</para></listitem>
                
        <listitem><para>The account used to connect to the Samba host
        must be a member of the <ulink 
        url="smb.conf.5.html#PRINTERADMIN"><parameter>printer 
        admin</parameter></ulink> list.</para></listitem>
</itemizedlist>

<para>
Of course, the connected account must still possess access
to add files to the subdirectories beneath [print$]. Remember
that all file shares are set to 'read only' by default.
</para>
</warning>


<para>
Once you have created the required [print$] service and 
associated subdirectories, simply log onto the Samba server using 
a root (or <parameter>printer admin</parameter>) account
from a Windows NT 4.0/2k client.  Open "Network Neighbourhood" or
"My Network Places" and browse for the Samba host.  Once you have located
the server, navigate to the "Printers..." folder.
You should see an initial listing of printers
that matches the printer shares defined on your Samba host.
</para>
</sect2>

<sect2>
<title>Setting Drivers for Existing Printers</title>

<para>The initial listing of printers in the Samba host's 
Printers folder will have no real printer driver assigned 
to them. This defaults to a NULL string to allow the use
of the local Add Printer Wizard on NT/2000 clients.
Attempting to view the printer properties for a printer
which has this default driver assigned will result in 
the error message:</para>

<para>
<emphasis>Device settings cannot be displayed.  The driver 
for the specified printer is not installed, only spooler 
properties will be displayed.  Do you want to install the 
driver now?</emphasis>
</para>

<para>
Click "No" in the error dialog and you will be presented with
the printer properties window.  The way to assign a driver to a 
printer is to either
</para>
        
<itemizedlist>
        <listitem><para>Use the "New Driver..." button to install 
        a new printer driver, or</para></listitem>
        
        <listitem><para>Select a driver from the popup list of 
        installed drivers.  Initially this list will be empty.</para>
        </listitem>
</itemizedlist>
        
<para>If you wish to install printer drivers for client 
operating systems other than "Windows NT x86", you will need 
to use the "Sharing" tab of the printer properties dialog.</para>

<para>Assuming you have connected with a root account, you 
will also be able modify other printer properties such as 
ACLs and device settings using this dialog box.</para>

<para>A few closing comments for this section, it is possible 
on a Windows NT print server to have printers
listed in the Printers folder which are not shared.  Samba does
not make this distinction.  By definition, the only printers of
which Samba is aware are those which are specified as shares in
<filename>smb.conf</filename>.</para>
  
<para>Another interesting side note is that Windows NT clients do
not use the SMB printer share, but rather can print directly 
to any printer on another Windows NT host using MS-RPC.  This
of course assumes that the printing client has the necessary
privileges on the remote host serving the printer.  The default
permissions assigned by Windows NT to a printer gives the "Print"
permissions to the "Everyone" well-known group.
</para>

</sect2>        


<sect2>
<title>Support a large number of printers</title>
                
<para>One issue that has arisen during the development
phase of Samba 2.2 is the need to support driver downloads for
100's of printers.  Using the Windows NT APW is somewhat 
awkward to say the list.  If more than one printer are using the 
same driver, the <ulink url="rpcclient.1.html"><command>rpcclient's
setdriver command</command></ulink> can be used to set the driver
associated with an installed driver.  The following is example
of how this could be accomplished:</para>
                
<para>
<prompt>$ </prompt><userinput>rpcclient pogo -U root%secret -c "enumdrivers"</userinput>
<programlisting> 
Domain=[NARNIA] OS=[Unix] Server=[Samba 2.2.0-alpha3]
 
[Windows NT x86]
Printer Driver Info 1:
     Driver Name: [HP LaserJet 4000 Series PS]
 
Printer Driver Info 1:
     Driver Name: [HP LaserJet 2100 Series PS]
 
Printer Driver Info 1:
     Driver Name: [HP LaserJet 4Si/4SiMX PS]
</programlisting>                                 
<prompt>$ </prompt><userinput>rpcclient pogo -U root%secret -c "enumprinters"</userinput>
<programlisting>
Domain=[NARNIA] OS=[Unix] Server=[Samba 2.2.0-alpha3]
     flags:[0x800000]
     name:[\\POGO\hp-print]
     description:[POGO\\POGO\hp-print,NO DRIVER AVAILABLE FOR THIS PRINTER,]
     comment:[]
                                  
</programlisting>
<prompt>$ </prompt><userinput>rpcclient pogo -U root%secret -c "setdriver hp-print \"HP LaserJet 4000 Series PS\""</userinput>
<programlisting>
Domain=[NARNIA] OS=[Unix] Server=[Samba 2.2.0-alpha3]
Successfully set hp-print to driver HP LaserJet 4000 Series PS.
</programlisting></para>
</sect2>



<sect2>
<title>Adding New Printers via the Windows NT APW</title>
        
<para>
By default, Samba offers all printer shares defined in <filename>smb.conf</filename>
in the "Printers..." folder.  Also existing in this folder is the Windows NT 
Add Printer Wizard icon.  The APW will be show only if
</para>

<itemizedlist>
        <listitem><para>The connected user is able to successfully
        execute an OpenPrinterEx(\\server) with administrative
        privileges (i.e. root or <parameter>printer admin</parameter>).
        </para></listitem>
        
        <listitem><para><ulink url="smb.conf.5.html#SHOWADDPRINTERWIZARD"><parameter>show 
        add printer wizard = yes</parameter></ulink> (the default).
        </para></listitem>
</itemizedlist>

<para>
In order to be able to use the APW to successfully add a printer to a Samba 
server, the <ulink url="smb.conf.5.html#ADDPRINTERCOMMAND"><parameter>add 
printer command</parameter></ulink> must have a defined value.  The program
hook must successfully add the printer to the system (i.e. 
<filename>/etc/printcap</filename> or appropriate files) and 
<filename>smb.conf</filename> if necessary.
</para>

<para>
When using the APW from a client, if the named printer share does 
not exist, <command>smbd</command> will execute the <parameter>add printer 
command</parameter> and reparse to the <filename>smb.conf</filename>
to attempt to locate the new printer share.  If the share is still not defined,
an error of "Access Denied" is returned to the client.  Note that the 
<parameter>add printer program</parameter> is executed under the context
of the connected user, not necessarily a root account.
</para>

<para>
There is a complementary <ulink url="smb.conf.5.html#DELETEPRINTERCOMMAND"><parameter>delete
printer command</parameter></ulink> for removing entries from the "Printers..."
folder.
</para>

<para>
The following is an example <ulink url="smb.conf.5.html#ADDPRINTERCOMMAN"><parameter>add printer command</parameter></ulink> script. It adds the appropriate entries to <filename>/etc/printcap.local</filename> (change that to what you need) and returns a line of 'Done' which is needed for the whole process to work.
</para>

<programlisting>
#!/bin/sh

# Script to insert a new printer entry into printcap.local
#
# $1, printer name, used as the descriptive name
# $2, share name, used as the printer name for Linux
# $3, port name
# $4, driver name
# $5, location, used for the device file of the printer
# $6, win9x location

#
# Make sure we use the location that RedHat uses for local printer defs
PRINTCAP=/etc/printcap.local
DATE=`date +%Y%m%d-%H%M%S`
LP=lp
RESTART="service lpd restart"

# Keep a copy
cp $PRINTCAP $PRINTCAP.$DATE
# Add the printer to $PRINTCAP
echo ""                                                 >> $PRINTCAP
echo "$2|$1:\\"                                         >> $PRINTCAP
echo "  :sd=/var/spool/lpd/$2:\\"                       >> $PRINTCAP
echo "  :mx=0:ml=0:sh:\\"                               >> $PRINTCAP
echo "  :lp=/usr/local/samba/var/print/$5.prn:"         >> $PRINTCAP

touch "/usr/local/samba/var/print/$5.prn" >> /tmp/printadd.$$ 2>&amp;1
chown $LP "/usr/local/samba/var/print/$5.prn" >> /tmp/printadd.$$ 2>&amp;1

mkdir /var/spool/lpd/$2
chmod 700 /var/spool/lpd/$2
chown $LP /var/spool/lpd/$2
#echo $1 >> "/usr/local/samba/var/print/$5.prn"
#echo $2 >> "/usr/local/samba/var/print/$5.prn"
#echo $3 >> "/usr/local/samba/var/print/$5.prn"
#echo $4 >> "/usr/local/samba/var/print/$5.prn"
#echo $5 >> "/usr/local/samba/var/print/$5.prn"
#echo $6 >> "/usr/local/samba/var/print/$5.prn"
$RESTART >> "/usr/local/samba/var/print/$5.prn"
# Not sure if this is needed
touch /usr/local/samba/lib/smb.conf
#
# You need to return a value, but I am not sure what it means.
#
echo "Done"
exit 0
</programlisting>

</sect2>


<sect2>
<title>Samba and Printer Ports</title>

<para>
Windows NT/2000 print servers associate a port with each printer.  These normally
take the form of LPT1:, COM1:, FILE:, etc...  Samba must also support the
concept of ports associated with a printer.  By default, only one printer port,
named "Samba Printer Port", exists on a system.  Samba does not really a port in
order to print, rather it is a requirement of Windows clients.  
</para>

<para>
Note that Samba does not support the concept of "Printer Pooling" internally 
either.  This is when a logical printer is assigned to multiple ports as 
a form of load balancing or fail over.
</para>

<para>
If you require that multiple ports be defined for some reason,
<filename>smb.conf</filename> possesses a <ulink 
url="smb.conf.5.html#ENUMPORTSCOMMAND"><parameter>enumports 
command</parameter></ulink> which can be used to define an external program 
that generates a listing of ports on a system.
</para>

</sect2>

</sect1>


<sect1>
        <title>The Imprints Toolset</title>
        
        <para>The Imprints tool set provides a UNIX equivalent of the 
        Windows NT Add Printer Wizard.  For complete information, please 
        refer to the Imprints web site at <ulink url="http://imprints.sourceforge.net/">
        http://imprints.sourceforge.net/</ulink> as well as the documentation 
        included with the imprints source distribution.  This section will 
        only provide a brief introduction to the features of Imprints.</para>
        
        
        <sect2>
                <title>What is Imprints?</title>

                <para>Imprints is a collection of tools for supporting the goals 
                of</para>
                
                <itemizedlist>
                        <listitem><para>Providing a central repository information 
                        regarding Windows NT and 95/98 printer driver packages</para>
                        </listitem>
                        
                        <listitem><para>Providing the tools necessary for creating 
                        the Imprints printer driver packages.</para></listitem>
                        
                        <listitem><para>Providing an installation client which 
                        will obtain and install printer drivers on remote Samba 
                        and Windows NT 4 print servers.</para></listitem>
                </itemizedlist>
                
        </sect2>
        
        
        <sect2>
                <title>Creating Printer Driver Packages</title>
                
                <para>The process of creating printer driver packages is beyond
                the scope of this document (refer to Imprints.txt also included
                with the Samba distribution for more information).  In short,
                an Imprints driver package is a gzipped tarball containing the
                driver files, related INF files, and a control file needed by the
                installation client.</para>
        </sect2>
        
        
        <sect2>
                <title>The Imprints server</title>
                
                <para>The Imprints server is really a database server that 
                may be queried via standard HTTP mechanisms.  Each printer 
                entry in the database has an associated URL for the actual
                downloading of the package.  Each package is digitally signed
                via GnuPG which can be used to verify that package downloaded
                is actually the one referred in the Imprints database.  It is 
                <emphasis>not</emphasis> recommended that this security check 
                be disabled.</para>
        </sect2>
        
        <sect2>
                <title>The Installation Client</title>

                <para>More information regarding the Imprints installation client 
                is available in the <filename>Imprints-Client-HOWTO.ps</filename> 
                file included with the imprints source package.</para>

                <para>The Imprints installation client comes in two forms.</para>

                <itemizedlist>
                        <listitem><para>a set of command line Perl scripts</para>
                        </listitem>
                        
                        <listitem><para>a GTK+ based graphical interface to 
                        the command line perl scripts</para></listitem>
                </itemizedlist>
                
                <para>The installation client (in both forms) provides a means
                of querying the Imprints database server for a matching
                list of known printer model names as well as a means to 
                download and install the drivers on remote Samba and Windows
                NT print servers.</para>

                <para>The basic installation process is in four steps and 
                perl code is wrapped around <command>smbclient</command> 
                and <command>rpcclient</command>.</para>

<para><programlisting>  
foreach (supported architecture for a given driver)
{
     1.  rpcclient: Get the appropriate upload directory 
         on the remote server
     2.  smbclient: Upload the driver files
     3.  rpcclient: Issues an AddPrinterDriver() MS-RPC
}
        
4.  rpcclient: Issue an AddPrinterEx() MS-RPC to actually
    create the printer
</programlisting></para>
                
                <para>One of the problems encountered when implementing 
                the Imprints tool set was the name space issues between 
                various supported client architectures.  For example, Windows 
                NT includes a driver named "Apple LaserWriter II NTX v51.8" 
                and Windows 95 calls its version of this driver "Apple 
                LaserWriter II NTX"</para>
                
                <para>The problem is how to know what client drivers have 
                been uploaded for a printer.  As astute reader will remember 
                that the Windows NT Printer Properties dialog only includes 
                space for one printer driver name.  A quick look in the 
                Windows NT 4.0 system registry at</para>
        
                <para><filename>HKLM\System\CurrentControlSet\Control\Print\Environment
                </filename></para>
                
                <para>will reveal that Windows NT always uses the NT driver 
                name.  This is ok as Windows NT always requires that at least 
                the Windows NT version of the printer driver is present.  
                However, Samba does not have the requirement internally.  
                Therefore, how can you use the NT driver name if is has not 
                already been installed?</para>
                
                <para>The way of sidestepping this limitation is to require 
                that all Imprints printer driver packages include both the Intel 
                Windows NT and 95/98 printer drivers and that NT driver is 
                installed first.</para>
        </sect2>
        
</sect1>

<!--

  This comment from rpc_server/srv_spoolss_nt.c:_spoolss_open_printer_ex()
  needs to be added into a section probably.  This is to remind me it needs 
  to be done.  -jerry

                /*
                 * If the openprinterex rpc call contains a devmode,
                 * it's a per-user one. This per-user devmode is derivated
                 * from the global devmode. Openprinterex() contains a per-user
                 * devmode for when you do EMF printing and spooling.
                 * In the EMF case, the NT workstation is only doing half the job
                 * of rendering the page. The other half is done by running the printer
                 * driver on the server.
                 * The EMF file doesn't contain the page description (paper size, orientation, ...).
                 * The EMF file only contains what is to be printed on the page.
                 * So in order for the server to know how to print, the NT client sends
                 * a devicemode attached to the openprinterex call.
                 * But this devicemode is short lived, it's only valid for the current print job.
                 *
                 * If Samba would have supported EMF spooling, this devicemode would
                 * have been attached to the handle, to sent it to the driver to correctly
                 * rasterize the EMF file.
                 *
                 * As Samba only supports RAW spooling, we only receive a ready-to-print file,
                 * we just act as a pass-thru between windows and the printer.
                 *
                 * In order to know that Samba supports only RAW spooling, NT has to call
                 * getprinter() at level 2 (attribute field) or NT has to call startdoc()
                 * and until NT sends a RAW job, we refuse it.
                 *
                 * But to call getprinter() or startdoc(), you first need a valid handle,
                 * and to get an handle you have to call openprintex(). Hence why you have
                 * a devicemode in the openprinterex() call.
                 *
                 *
                 * Differences between NT4 and NT 2000.
                 * NT4:
                 * 
                 * On NT4, you only have a global devicemode. This global devicemode can be changed
                 * by the administrator (or by a user with enough privs). Every time a user
                 * wants to print, the devicemode is reset to the default. In Word, every time
                 * you print, the printer's characteristics are always reset to the global devicemode.
                 *
                 * NT 2000:
                 * 
                 * In W2K, there is the notion of per-user devicemode. The first time you use
                 * a printer, a per-user devicemode is build from the global devicemode.
                 * If you change your per-user devicemode, it is saved in the registry, under the
                 * H_KEY_CURRENT_KEY sub_tree. So that every time you print, you have your default
                 * printer preferences available.
                 *
                 * To change the per-user devicemode: it's the "Printing Preferences ..." button
                 * on the General Tab of the printer properties windows.
                 *
                 * To change the global devicemode: it's the "Printing Defaults..." button
                 * on the Advanced Tab of the printer properties window.
-->

<sect1>
<title>Diagnosis</title>

<sect2>
<title>Introduction</title>

<para>
This is a short description of how to debug printing problems with
Samba. This describes how to debug problems with printing from a SMB
client to a Samba server, not the other way around. For the reverse
see the examples/printing directory.
</para>

<para>
Ok, so you want to print to a Samba server from your PC. The first
thing you need to understand is that Samba does not actually do any
printing itself, it just acts as a middleman between your PC client
and your Unix printing subsystem. Samba receives the file from the PC
then passes the file to a external "print command". What print command
you use is up to you.
</para>

<para>
The whole things is controlled using options in smb.conf. The most
relevant options (which you should look up in the smb.conf man page)
are:
</para>

<para><programlisting>
      [global]
        print command     - send a file to a spooler
        lpq command       - get spool queue status
        lprm command      - remove a job
      [printers]
        path = /var/spool/lpd/samba
</programlisting></para>

<para>
The following are nice to know about:
</para>

<para><programlisting>
        queuepause command   - stop a printer or print queue
        queueresume command  - start a printer or print queue
</programlisting></para>

<para>
Example:
</para>

<para><programlisting>
        print command = /usr/bin/lpr -r -P%p %s
        lpq command   = /usr/bin/lpq    -P%p %s
        lprm command  = /usr/bin/lprm   -P%p %j
        queuepause command = /usr/sbin/lpc -P%p stop
        queuepause command = /usr/sbin/lpc -P%p start
</programlisting></para>

<para>
Samba should set reasonable defaults for these depending on your
system type, but it isn't clairvoyant. It is not uncommon that you
have to tweak these for local conditions.  The commands should
always have fully specified pathnames,  as the smdb may not have
the correct PATH values.
</para>

<para>
When you send a job to Samba to be printed,  it will make a temporary
copy of it in the directory specified in the [printers] section.
and it should be periodically cleaned out.  The lpr -r option
requests that the temporary copy be removed after printing; If
printing fails then you might find leftover files in this directory,
and it should be periodically cleaned out.  Samba used the lpq
command to determine the "job number" assigned to your print job
by the spooler.
</para>

<para>
The %&gt;letter&lt; are "macros" that get dynamically replaced with appropriate
values when they are used. The %s gets replaced with the name of the spool
file that Samba creates and the %p gets replaced with the name of the
printer. The %j gets replaced with the "job number" which comes from
the lpq output.
</para>

</sect2>

<sect2>
<title>Debugging printer problems</title>

<para>
One way to debug printing problems is to start by replacing these
command with shell scripts that record the arguments and the contents
of the print file. A simple example of this kind of things might
be:
</para>

<para><programlisting>
        print command = /tmp/saveprint %p %s

    #!/bin/saveprint
    # we make sure that we are the right user
    /usr/bin/id -p >/tmp/tmp.print
    # we run the command and save the error messages
    # replace the command with the one appropriate for your system
    /usr/bin/lpr -r -P$1 $2 2>>&amp;/tmp/tmp.print
</programlisting></para>

<para>
Then you print a file and try removing it.  You may find that the
print queue needs to be stopped in order to see the queue status
and remove the job:
</para>

<para><programlisting>

h4: {42} % echo hi >/tmp/hi
h4: {43} % smbclient //localhost/lw4
added interface ip=10.0.0.4 bcast=10.0.0.255 nmask=255.255.255.0
Password: 
Domain=[ASTART] OS=[Unix] Server=[Samba 2.0.7]
smb: \> print /tmp/hi
putting file /tmp/hi as hi-17534 (0.0 kb/s) (average 0.0 kb/s)
smb: \> queue
1049     3            hi-17534
smb: \> cancel 1049
Error cancelling job 1049 : code 0
smb: \> cancel 1049
Job 1049 cancelled
smb: \> queue
smb: \> exit
</programlisting></para>

<para>
The 'code 0' indicates that the job was removed.  The comment
by the  smbclient is a bit misleading on this.
You can observe the command output and then and look at the
/tmp/tmp.print file to see what the results are.  You can quickly
find out if the problem is with your printing system.  Often people
have problems with their /etc/printcap file or permissions on
various print queues.
</para>
</sect2>

<sect2>
<title>What printers do I have?</title>

<para>
You can use the 'testprns' program to check to see if the printer
name you are using is recognized by Samba.  For example,  you can
use:
</para>

<para><programlisting>
    testprns printer /etc/printcap
</programlisting></para>

<para>
Samba can get its printcap information from a file or from a program.
You can try the following to see the format of the extracted
information:
</para>

<para><programlisting>
    testprns -a printer /etc/printcap

    testprns -a printer '|/bin/cat printcap'
</programlisting></para>

</sect2>

<sect2>
<title>Setting up printcap and print servers</title>

<para>
You may need to set up some printcaps for your Samba system to use.
It is strongly recommended that you use the facilities provided by
the print spooler to set up queues and printcap information.
</para>

<para>
Samba requires either a printcap or program to deliver printcap
information.  This printcap information has the format:
</para>

<para><programlisting>
  name|alias1|alias2...:option=value:...
</programlisting></para>

<para>
For almost all printing systems, the printer 'name' must be composed
only of alphanumeric or underscore '_' characters.  Some systems also
allow hyphens ('-') as well.  An alias is an alternative name for the
printer,  and an alias with a space in it is used as a 'comment'
about the printer.  The printcap format optionally uses a \ at the end of lines
to extend the printcap to multiple lines.
</para>

<para>
Here are some examples of printcap files:
</para>

<para>
<orderedlist>
<listitem><para>
pr              just printer name
</para></listitem>
<listitem><para>
pr|alias        printer name and alias
</para></listitem>
<listitem><para>
pr|My Printer   printer name, alias used as comment
</para></listitem>
<listitem><para>
pr:sh:\        Same as pr:sh:cm= testing
  :cm= \ 
  testing
</para></listitem>
<listitem><para>
pr:sh           Same as pr:sh:cm= testing
  :cm= testing
</para></listitem>
</orderedlist>
</para>

<para>
Samba reads the printcap information when first started.  If you make
changes in the printcap information, then you must do the following:
</para>

<orderedlist>

<listitem><para>
make sure that the print spooler is aware of these changes.
The LPRng system uses the 'lpc reread' command to do this.
</para></listitem>

<listitem><para>
make sure that the spool queues, etc., exist and have the
correct permissions.  The LPRng system uses the 'checkpc -f'
command to do this.
</para></listitem>

<listitem><para>
You now should send a SIGHUP signal to the smbd server to have
it reread the printcap information.
</para></listitem>
</orderedlist>

</sect2>

<sect2>
<title>Job sent, no output</title>

<para>
This is the most frustrating part of printing.  You may have sent the
job,  verified that the job was forwarded,  set up a wrapper around
the command to send the file,  but there was no output from the printer.
</para>

<para>
First,  check to make sure that the job REALLY is getting to the
right print queue.  If you are using a BSD or LPRng print spooler,
you can temporarily stop the printing of jobs.  Jobs can still be
submitted, but they will not be printed.  Use:
</para>

<para><programlisting>
  lpc -Pprinter stop
</programlisting></para>

<para>
Now submit a print job and then use 'lpq -Pprinter' to see if the
job is in the print queue.  If it is not in the print queue then
you will have to find out why it is not being accepted for printing.
</para>

<para>
Next, you may want to check to see what the format of the job really
was.  With the assistance of the system administrator you can view
the submitted jobs files.  You may be surprised to find that these
are not in what you would expect to call a printable format.
You can use the UNIX 'file' utitily to determine what the job
format actually is:
</para>

<para><programlisting>
    cd /var/spool/lpd/printer   # spool directory of print jobs
    ls                          # find job files
    file dfA001myhost
</programlisting></para>

<para>
You should make sure that your printer supports this format OR that
your system administrator has installed a 'print filter' that will
convert the file to a format appropriate for your printer.
</para>

</sect2>

<sect2>
<title>Job sent, strange output</title>

<para>
Once you have the job printing, you can then start worrying about
making it print nicely.
</para>

<para>
The most common problem is extra pages of output: banner pages
OR blank pages at the end.
</para>

<para>
If you are getting banner pages,  check and make sure that the
printcap option or printer option is configured for no banners.
If you have a printcap,  this is the :sh (suppress header or banner
page) option.  You should have the following in your printer.
</para>

<para><programlisting>
   printer: ... :sh
</programlisting></para>

<para>
If you have this option and are still getting banner pages,  there
is a strong chance that your printer is generating them for you
automatically.  You should make sure that banner printing is disabled
for the printer.  This usually requires using the printer setup software
or procedures supplied by the printer manufacturer.
</para>

<para>
If you get an extra page of output,  this could be due to problems
with your job format,  or if you are generating PostScript jobs,
incorrect setting on your printer driver on the MicroSoft client.
For example, under Win95 there is a option:
</para>

<para><programlisting>
  Printers|Printer Name|(Right Click)Properties|Postscript|Advanced|
</programlisting></para>

<para>
that allows you to choose if a Ctrl-D is appended to all jobs.
This is a very bad thing to do, as most spooling systems will
automatically add a ^D to the end of the job if it is detected as
PostScript.  The multiple ^D may cause an additional page of output.
</para>

</sect2>

<sect2>
<title>Raw PostScript printed</title>

<para>
This is a problem that is usually caused by either the print spooling
system putting information at the start of the print job that makes
the printer think the job is a text file, or your printer simply
does not support PostScript.  You may need to enable 'Automatic
Format Detection' on your printer.
</para>

</sect2>

<sect2>
<title>Advanced Printing</title>

<para>
Note that you can do some pretty magic things by using your
imagination with the "print command" option and some shell scripts.
Doing print accounting is easy by passing the %U option to a print
command shell script. You could even make the print command detect
the type of output and its size and send it to an appropriate
printer.
</para>

</sect2>

<sect2>
<title>Real debugging</title>

<para>
If the above debug tips don't help, then maybe you need to bring in
the bug guns, system tracing. See Tracing.txt in this directory.
</para>
</sect2>
</sect1>

</chapter>