[Pkg-cups-devel] Bug#523124: CUPS has stale printers appearing if browsing whith short names is enabled and another host suddently changes its ip

Wed Apr 8 17:15:39 UTC 2009

Package: cups
Version: 1.3.8-1lenny4.1

Context : local cupsd accepts browsing messages, with BrowseShortNames
enabled.

if a remote cupsd server which publishes printers changes suddently its IP a
new printer with a long name (but the same name before '@') is created
locally and old one still exists (this is not the bug).

The problem is that the short name becomes quickly stale in the sense that
it becomes bound to the device URI file:/dev/null, never expires and
survives restarts of cupsd service.

Moreover cupsd still considers these stale printers as valid printers and it
is possible to have jobs waiting to be printed by these non-existant
printers.

The only way to get rid of these entries is to stop cupsd, remove stale
entries from /var/cache/cups/remote.cache and restart cupsd.

The solution would be to allow these stale entries to expire the same way as
normal printers, as any device listed in remote.cache shoud do.

For example, I have on my system two of these stale printers, as lpstat -v
shows :

$ lpstat -v
device for HP_Deskjet_F300_series: /dev/null
device for HP_Deskjet_F300_series at MacBook250Go-2.local: ipp://MacBook250Go-2.local:631/printers/HP_Deskjet_F300_series
device for SONA: ipp://sona/ipp/
device for wifi_HP_Deskjet_F300_series: /dev/null
device for wifi_HP_Deskjet_F300_series at MacBook250Go-2.local: ipp://MacBook250Go-2.local:631/printers/wifi_HP_Deskjet_F300_series

Clearly the address of MacBook250Go-2.local changed at some point of the day
(maybe hours before), but the stale printers did not disappear.

The corresponding /var/cache/cups/remote.cache :
|# Remote cache file for CUPS v1.3.8
|# Written by cupsd on 2009-04-08 18:56
|<Printer HP_Deskjet_F300_series>
|Type 16879620
|BrowseTime 1239199085
|Info HP Deskjet F300 series
|Location Ordinateur de Roberto Mantaci (2)
|DeviceURI file:/dev/null
|State Idle
|Accepting Yes
|JobSheets none none
|</Printer>
|<Printer HP_Deskjet_F300_series at MacBook250Go-2.local>
|Type 16814086
|BrowseTime 1239210058
|Info HP Deskjet F300 series
|MakeModel HP DeskJet F300 Series All in One on MacBook250Go-2.local
|Location Ordinateur de Roberto Mantaci (2)
|DeviceURI ipp://MacBook250Go-2.local:631/printers/HP_Deskjet_F300_series
|State Idle
|Accepting Yes
|JobSheets none none
|Option job-sheets none,none
|Option lease-duration 300
|</Printer>
|<Printer wifi_HP_Deskjet_F300_series>
|Type 16887820
|BrowseTime 1239199085
|Info wifi HP Deskjet F300 series
|Location Base Station 0968e5
|DeviceURI file:/dev/null
|State Idle
|Accepting Yes
|JobSheets none none
|</Printer>
|<Printer wifi_HP_Deskjet_F300_series at MacBook250Go-2.local>
|Type 16822286
|BrowseTime 1239210060
|Info wifi HP Deskjet F300 series
|MakeModel HP Deskjet F2100 series on MacBook250Go-2.local
|Location Base Station 0968e5
|DeviceURI
|ipp://MacBook250Go-2.local:631/printers/wifi_HP_Deskjet_F300_series
|State Idle
|Accepting Yes
|JobSheets none none
|Option job-sheets none,none
|Option lease-duration 300
|</Printer>

Note that stale entries do not have a "Option lease-duration 300", so they
will not expire on the next cupsd start.

My printers.conf:
|# Printer configuration file for CUPS v1.3.8
|# Written by cupsd on 2009-03-30 18:21
|<Printer SONA>
|Info HP laserjet 4350
|Location LIAFA
|DeviceURI ipp://sona/ipp/
|State Idle
|StateTime 1238430050
|Accepting Yes
|Shared No
|JobSheets none none
|QuotaPeriod 0
|PageLimit 0
|KLimit 0
|OpPolicy default
|ErrorPolicy stop-printer
|</Printer>
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