[Samba] Print limiting

Fri Nov 22 16:29:02 GMT 2002

On Fri, Nov 22, 2002 at 11:44:31AM +0200, Vasco Macaringue wrote on Samba-Digest:

> Message: 12 
> Date: Fri, 22 Nov 2002 07:18:34 -0500 
> From: Joel Hammer <Joel at HammersHome.com> 
> To: Vasco Macaringue <macaring at nambu.uem.mz>, samba at lists.samba.org 
> Subject: Re: [Samba] Print limiting 
> 
> I have never seen that feature discussed on this board. I may have missed it. 
> It would be doubtful if samba could do what you want. Samba is a rather brain 
> dead print server. All it does is: 
> 1. Accepts a filtered print job from the client. 
> 2. Invokes the server's printing command to print it. I don't think samba can 
> tell how many pages are in the document. I suspect you will have to delve into 
> the workings of your server's printing software to find a solution 
> Joel 

The feature you want is dependent on the real print subsystem
you're using. Samba's part is always to receive the job files
from the clients (filtered *or* unfiltered) and hand it over
to this printing subsystem.

Of course one could "hack" things with one's own scripts.

But there is CUPS (Common Unix Printing System). CUPS supports "quotas".
Quotas can be based on sizes of jobs or on the number of pages or both,
and are spanning any time period you want.

This is an example command how root would set a print quota in CUPS,
assuming an existing printer named "quotaprinter":

  lpadmin -p quotaprinter -o job-quota-period=604800 -o job-k-limit=1024 -o job-page-limit=100

This would limit every single user to print 100 pages or 1024 KB of
data (whichever comes first) within the last 604.800 seconds ( = 1 week).

For CUPS to count correctly, the printfile needs to pass the CUPS
"pstops" filter, otherwise it uses a "dummy" count of "1". (Some
printfiles don't pass it -- f.e. image files -- but then those are
mostly 1 page jobs anyway). This also means, proprietary drivers for
the target printer running on the client computers and CUPS/Samba
then spooling these files as "raw" (i.e. leaving them untouched, not
filtering them), will be counted as "1-pagers" too!

You need to send PostScript from the clients (i.e. run a PostScript
driver there) for having the chance to get accounting done. If the
printer is a non-PostScript model, you need to let CUPS do the job to
convert the file to a print-ready format for the target printer. This
will be working for currently ~1.000 different printer models, see

     http://www.linuxprinting.org/printer_list.cgi

Before CUPS-1.1.16 your only option was to use the Adobe PostScript
Driver on the Windows clients. The output of this driver was not always
passed thru the "pstops" filter on the CUPS/Samba side, and therefor was
not counted correctly (the reason is that it often --- depending on the
"PPD" being used --- did write a "PJL"-header in front of the real
PostScript which made CUPS to skip the pstops and go directy to
the "pstoraster" stage).

 From CUPS-1.1.16 onward you can use the "CUPS PostScript Driver
for Windows NT/2K/XP clients" (it is tagged in the download area of
http://www.cups.org/ as the "cups-samba-1.1.16.tar.gz" package).
It is *not* working for Win9x/ME clients. But it....

   ...it guarantees to not write an PJL-header;
   ...it guarantees to still read and support all PJL-options named
      in the driver PPD with its own means;
   ...it guarantees the file going thru the "pstops" filter on the
      CUPS/Samba server;
   ...it guarantees to page-count correctly the printfile...

You can read more about the setup of this combination in the
manpage for "cupsaddsmb" (only present with CUPS installed, only
current with CUPS 1.1.16).

These are the items CUPS logs in the "page_log" for every single
*page* of a job:

* Printer name
* User name
* Job ID
* Time of printing
* the page number
* the number of copies
* a billing info string (optional)

Here is an extract of my CUPS server's page_log file to illustrate
the format and included items:

infotec_IS2027 kurt 40 [22/Nov/2002:13:18:03 +0100] 1 2  #marketing
infotec_IS2027 kurt 40 [22/Nov/2002:13:18:03 +0100] 2 2  #marketing
infotec_IS2027 kurt 40 [22/Nov/2002:13:18:03 +0100] 3 2  #marketing
infotec_IS2027 kurt 40 [22/Nov/2002:13:18:03 +0100] 4 2  #marketing
infotec_IS2027 kurt 40 [22/Nov/2002:13:18:03 +0100] 5 2  #marketing
infotec_IS2027 kurt 40 [22/Nov/2002:13:18:03 +0100] 6 2  #marketing

This was Job ID "40", printed on "infotec_IS2027" by user "kurt",
a 6-page job printed in 2 copies and billed to "#marketing"...

Which flaws or shortcomings are there?

  * the ones named above;
  * CUPS really counts the job pages being *processsed in software*
    (going thru the "RIP") rather than the physical sheets successfully
    leaving the printing device -- if there is a jam while printing
    the 5th sheet out of 1000 and the job is aborted by the printer,
    the "page count" will still show the figure of 1000 for that
    job;
  * all quotas are the same for all users (no flexibility to
    give the boss a higher quota than the clerk)
  * no support for groups;
  * no means to read out the current balance or "used-up"
    number of current quota;
  * a user having used up 99 sheets of 100 quota will still be
    able to send and print a 1.000 sheet job;
  * a user being denied a job because of a filled-up quota
    doesn't get a meaningful error message from CUPS other than
    "client-error-not-possible".

But this is the best system out there currently. And there are
huge improvements under development:

--> page counting will go into the "backends" (these talk directly
     to the printer and will increase the count in sync with the
     actual printing process  -- a jam at the 5th sheet will lead
     to a stop in the counting...)

--> quotas will be handled more flexibly;

--> probably there will be support for users to inquire their
     "accounts" in advance;

--> probably there will be support for some other tools around
     this topic...

Other than the current stage of the CUPS development, I don't
know any other ready-to-use tool which you could consider.

I hope this clarifies the options.

Cheers,
Kurt

> On Fri, Nov 22, 2002 at 11:44:31AM +0200, Vasco Macaringue wrote:
> 
>> Hi all
>> This is my first time writting to samba
>> 
>> I'd like to get a quickly help in this:
>> Where can I find a program or how can I configure my samba server in order
>> to limit the number of pages to be printed by users.
>> 
>> Best regards
>> 
>> 
>> 
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