[Pkg-cups-devel] Bug#644205: "Backend /usr/lib/cups/backend/parallel does not exist!" - but it does...

ael law_ence.dev at ntlworld.com
Mon Oct 3 22:05:08 UTC 2011


Package: cups
Version: 1.5.0-8
Severity: normal

Dear Maintainer,
*** Please consider answering these questions, where appropiate ***

   * What led up to the situation?
   * What exactly did you do (or not do) that was effective (or
     ineffective)?
   * What was the outcome of this action?
   * What outcome did you expect instead?
----------------------------------------------------------------------

I have a parallel laser printer which has worked very well for several
years under cups.

But now, printing is impossible because the printer is paused
with the message 
 Backend /usr/lib/cups/backend/parallel does not exist!

However, it does exist:

$ ls -l /usr/lib/cups/backend/parallel 
-r-xr-xr-x 2 root root 30116 Sep 27 14:14 /usr/lib/cups/backend/parallel

The error message is written to /etc/printers.conf:
# Printer configuration file for CUPS v1.5.0
# Written by cupsd
# DO NOT EDIT THIS FILE WHEN CUPSD IS RUNNING
<Printer HL1250>
UUID urn:uuid:04b22af5-e55f-39b4-61c8-01cd8f0201f1
Info Brother HL1250
Location CR
MakeModel Brother HL-1250 Foomatic/hl1250 (recommended)
DeviceURI parallel:/dev/lp0
State Stopped
StateMessage Backend /usr/lib/cups/backend/parallel does not exist!   <====
StateTime 1248035586
Reason paused
Type 8433668
Accepting Yes
Shared Yes
JobSheets none none
QuotaPeriod 0
PageLimit 0
KLimit 0
OpPolicy default
ErrorPolicy stop-printer
</Printer>
......
-----------------------------------------------------------

I can write data to the printer with cat "testing \n" > /dev/lp0, so 
that part of the system is fine.

I can run "parallel" as root as follows:

# /usr/lib/cups/backend/parallel 
direct parallel:/dev/lp0 "unknown" "LPT #1" "" ""

/etc/cupsd.conf:-
--------------------------------------------
LogLevel info

# Deactivate CUPS' internal logrotating, as we provide a better one, especially
# LogLevel debug2 gets usable now
MaxLogSize 0

SystemGroup lpadmin
# Allow remote access
Port 631
Listen /var/run/cups/cups.sock
# Enable printer sharing and shared printers.
Browsing On
BrowseOrder allow,deny
BrowseAllow all

BrowseAddress @LOCAL
DefaultAuthType Basic
<Location />
  Allow all
  # Allow shared printing...
  Order allow,deny
  Allow @LOCAL
</Location>
<Location /admin>
  Encryption Required
  Allow localhost
  # Restrict access to the admin pages...
  Order allow,deny
</Location>

# Restrict access to configuration files...

<Location /admin/conf>
  AuthType Basic
  Require user @SYSTEM
  Allow localhost
  # Restrict access to the configuration files...
  Order allow,deny
</Location>

# Set the default printer/job policies...
<Policy default>
  <Limit Send-Document Send-URI Hold-Job Release-Job Restart-Job Purge-Jobs Set-Job-Attributes Create-Job-Subscription Renew-Subscription Cancel-Subscription Get-Notifications Reprocess-Job Cancel-Current-Job Suspend-Current-Job Resume-Job CUPS-Move-Job CUPS-Get-Document>
    Require user @OWNER @SYSTEM
    Order deny,allow
  </Limit>

 # All administration operations require an administrator to authenticate..
  <Limit CUPS-Add-Modify-Printer CUPS-Delete-Printer CUPS-Add-Modify-Class CUPS-Delete-Class CUPS-Set-Default CUPS-Get-Devices>
    AuthType Default
    Require user @SYSTEM
    Order deny,allow
  </Limit>

  # All printer operations require a printer operator to authenticate...

  <Limit Pause-Printer Resume-Printer Set-Printer-Attributes Enable-Printer Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs Release-Held-New-Jobs Deactivate-Printer Activate-Printer Restart-Printer Shutdown-Printer Startup-Printer Promote-Job Schedule-Job-After CUPS-Add-Printer CUPS-Delete-Printer CUPS-Add-Class CUPS-Delete-Class CUPS-Accept-Jobs CUPS-Reject-Jobs CUPS-Set-Default>
    AuthType Basic
    Require user @SYSTEM
    Order deny,allow
  </Limit>

  <Limit CUPS-Authenticate-Job>
    Require user @OWNER @SYSTEM
    Order deny,allow
  </Limit>

 # Only the owner or an administrator can cancel or authenticate a job...
<Limit Cancel-Job CUPS-Authenticate-Job>
    Require user @OWNER @SYSTEM
    Order deny,allow
  </Limit>

   <Limit All>
    Order deny,allow
  </Limit>
</Policy>

# Set the authenticated printer/job policies...
<Policy authenticated>
  # Job-related operations must be done by the owner or an administrator...
  <Limit Create-Job Print-Job Print-URI>
    AuthType Default
    Order deny,allow
  </Limit>

  <Limit Send-Document Send-URI Hold-Job Release-Job Restart-Job Purge-Jobs Set-Job-Attributes Create-Job-Subscription Renew-Subscription Cancel-Subscription Get-Notifications Reprocess-Job Cancel-Current-Job Suspend-Current-Job Resume-Job CUPS-Move-Job CUPS-Get-Document>
    AuthType Default
    Require user @OWNER @SYSTEM
    Order deny,allow
  </Limit>

  # All administration operations require an administrator to authenticate...
  <Limit CUPS-Add-Modify-Printer CUPS-Delete-Printer CUPS-Add-Modify-Class CUPS-Delete-Class CUPS-Set-Default>
    AuthType Default
    Require user @SYSTEM
    Order deny,allow
  </Limit>

  # All printer operations require a printer operator to authenticate...
  <Limit Pause-Printer Resume-Printer Enable-Printer Disable-Printer Pause-Printer-After-Current-Job Hold-New-Jobs Release-Held-New-Jobs Deactivate-Printer Activate-Printer Restart-Printer Shutdown-Printer Startup-Printer Promote-Job Schedule-Job-After CUPS-Accept-Jobs CUPS-Reject-Jobs>
    AuthType Default
    Require user @SYSTEM
    Order deny,allow
  </Limit>

  # Only the owner or an administrator can cancel or authenticate a job...
  <Limit Cancel-Job CUPS-Authenticate-Job>
    AuthType Default
    Require user @OWNER @SYSTEM
    Order deny,allow
  </Limit>

  <Limit All>
    Order deny,allow
  </Limit>
</Policy>

Printcap /var/run/cups/printcap

-----------------------------------------------------

So I am not sure where to go from here, unless it is a simple
permission error.

I have been away for a period, so I am not quite sure which cups
upgrade introduced this bug, but it is fairly recent. Perhaps
1.4.8-2 -> 1.5.0-8 or more likely 1.4.7-1 -> 1.4.8-2 .


-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (990, 'testing')
Architecture: i386 (i686)

Kernel: Linux 3.0.0-rc4+ (PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_GB.UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages cups depends on:
ii  adduser                3.113           
ii  bc                     1.06.95-2       
ii  cups-client            1.5.0-8         
ii  cups-common            1.5.0-8         
ii  cups-ppdc              1.5.0-8         
ii  debconf [debconf-2.0]  1.5.40          
ii  ghostscript            9.02~dfsg-3     
ii  libavahi-client3       0.6.30-5        
ii  libavahi-common3       0.6.30-5        
ii  libc6                  2.13-21         
ii  libcups2               1.5.0-8         
ii  libcupscgi1            1.5.0-8         
ii  libcupsdriver1         1.5.0-8         
ii  libcupsimage2          1.5.0-8         
ii  libcupsmime1           1.5.0-8         
ii  libcupsppdc1           1.5.0-8         
ii  libdbus-1-3            1.4.16-1        
ii  libgcc1                1:4.6.1-4       
ii  libgnutls26            2.12.10-2       
ii  libgssapi-krb5-2       1.9.1+dfsg-1    
ii  libijs-0.35            0.35-8          
ii  libkrb5-3              1.9.1+dfsg-1    
ii  liblcms1               1.19.dfsg-1     
ii  libldap-2.4-2          2.4.25-3        
ii  libpam0g               1.1.3-2         
ii  libpaper1              1.1.24+nmu1     
ii  libpoppler13           0.16.7-2+b1     
ii  libslp1                1.2.1-7.8       
ii  libstdc++6             4.6.1-4         
ii  libusb-0.1-4           2:0.1.12-19     
ii  lsb-base               3.2-28          
ii  poppler-utils          0.16.7-2+b1     
ii  procps                 1:3.2.8-11      
ii  ssl-cert               1.0.28          
ii  ttf-freefont           20100919-1      
ii  zlib1g                 1:1.2.3.4.dfsg-3

Versions of packages cups recommends:
ii  avahi-daemon            0.6.30-5   
ii  colord                  0.1.11-1   
ii  cups-driver-gutenprint  5.2.7-2    
ii  foomatic-filters        4.0.9-1    
ii  ghostscript-cups        9.02~dfsg-3

Versions of packages cups suggests:
ii  cups-bsd     1.5.0-8        
ii  cups-pdf     <none>         
ii  foomatic-db  20110803-3     
ii  hplip        <none>         
ii  smbclient    2:3.5.11~dfsg-1
ii  udev         172-1          

-- Configuration Files:
/etc/cups/cupsd.conf [Errno 13] Permission denied: u'/etc/cups/cupsd.conf'

-- debconf information:
* cupsys/backend: ipp, parallel, socket
* cupsys/raw-print: false





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