[sane-devel] scanbd ... next steps / questions ...

Wilhelm Meier wilhelm.wm.meier at googlemail.com
Wed May 3 20:58:14 UTC 2017

Am 03.05.2017 um 19:50 schrieb Dr.-Ing. Dieter Jurzitza:
> Hi Axel,
> thank you very much for your feedback - I hope to have more spare time next 
> weekend to dive again into this issue.
> But in general: I had had thought that there is a "generic" dll.conf having 
> only the net - backend enabled that sits in /etc/saned (after configuration of 
> scanbd). This I took from the README.txt:
> *******************************************
> 6) sane config
> All desktop applications should only get access to the scanners via the net
> backend, so edit /etc/sane.d/dll.conf to only contain the net-backend on the 
> desktop machines. 
> example dll.conf:
> ---
> net
> ---
> *******************************************
> but somewhere there is a need to tell sane which physical device to use, so I 
> thought - maybe erratically - that scanbd "hides" other entries / a different 
> dll.conf in /etc/saned from sane and tells sane itself which scanner to use 
> but depicts to the "outer world" that there is nothing but a network scanner. 
> As readily said, this may be totally wrong. If I read your comments it sounds 
> as if the sane - configuration ought to remain "as is", but this is not what 
> the above mentioned entry in README.txt from scanbd tells me.

Please read the ReadMe.txt carefully ;-)

All local scan-applications like xsane e.g. have to use the net-backend.
This is the only way to intercept a scan-request by scanbd. scanbd in
turn has to start saned to perform the real scan. saned itself use the
normal way for configuration: it normally would use the
/etc/sane/dll.conf, but this would be wrong since it leads to an
infinity recursion via the net backend. Therefore scanbd uses the
SANE_CONFIG_DIR to point saned to another location to find an
alternative dll.conf - and this dll.conf should only contain the local
attached scanners (or remote on other machines).

Sounds a bit complicated, but this is the way it is ...


> Regards,
> thanks for all the work
> Dieter Jurzitza
> Am Donnerstag, 27. April 2017, 15:29:09 schrieb Axel Schöner:
>> Am Samstag, 22. April 2017, 19:02:57 CEST schrieb Dr.-Ing. Dieter Jurzitza:
>>> Dear listmembers,
>>> probably these questions have readily been asked over and over again, then
>>> my apologies:
>>> 1.) /etc/scanbd/scripts
>>> which scripts does this refer to? There are some scripts in /etc/scanbd,
>>> those like "scanadf.script" and "test.script" (I am using a spec - file
>>> for
>>> opensuse some other person had had generated)? If I look into
>>> /etc/scanbd/scanbd.conf they ought to reside within /etc/scanbd/scripts,
>>> is
>>> that correct? Is there a configure - option that would print out all
>>> directories in use (or, even better, put this summarizing into config.log
>>> like several other packages do / emacs is a nice example in this regard
>>> ...)?
>> The scripts which are executed while device insertion/removal and by pushing
>> buttons should be located in ${prefix}/etc/scanbd/scripts. We will fix the
>> makefiles... to correct this (in the next days).
>>> 2.) /usr/lib64/scanbd/scanbuttond/backends, is this the directory I should
>>> copy /etc/saned/dll.conf to as well as all the other files from /etc/saned
>>> that are uncommented within *this* dll.conf (except net.conf) in contrast
>>> to /etc/saned/dll.conf that ought to contain no reference but "net"? Is
>>> this what is menat with "backends"?
>> I think these files should be in ${prefix}/etc/saned/. Where do you have
>> this information from?
>>> 3.) SCANBD_DEVICE could be /dev/scanner (if I have such a device?)
>> In most cases there is no such devicenode.
>> It could be something like plustek:libusb:001:003.
>> When you plug in your device it should be detected if there is a supported
>> driver configured. Look at the end of ${prefix}/etc/saned/scanbd.conf
>>> 4.) SCANBD_ACTION - I do not really understand what is about this.
>> This is a variable which represents the actual event (insert, remove, scan,
>> copy, ...) the definitions are in scanbd.conf.
>> It is possible to trigger different scripts based on these events (if you
>> have more then one detected button on your scanner).
>> You can launch scanbd in debug mode to see the values of SCANBD_DEVICE and
>> SCANBD_ACTION: ${prefix}/sbin/scanbd -d7 -f -c
>> ${prefix}/etc/scanbd/scanbd.conf .
>>> From within the "README.txt in the source-directory I did not really
>>> understand what is meant with the variables - would it be too much to
>>> simply ask for an example that would shed some light on the do's and
>>> don'ts of the configuration if the "regular" scanner would be say "hp"
>>> and the
>>> corresponding device would be "/dev/scanner"?
>>> I am trying to set up a spec - file for a rpm - package, but as of now
>>> there is too much understanding missing on my side to get that tracked
>>> down in such a way that I can be satisfied with the results ....
>>> Thank you very much,
>>> regards
>>> Dieter Jurzitza

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