[sane-devel] improve scanbd for Debian

[Wilhelm]

Am 17.12.2014 um 17:01 schrieb Rolf Leggewie:
> Wilhelm,
> 
> thank you for your reply.
> 
> On 17.12.2014 22:34, Wilhelm wrote:
>>>> The dll.conf files were not
>>>> set up according to above requirements but when I changed them that
>>>> way everything stopped working, including scanbd from the command
>>>> line or even "scanimage -L".  
>>
>> what stopped working?
> 
> The scanner isn't found anymore.
> 
>>>> sane-find-scanner would continue to
>>>> find the device, though.
>>
>> without SANE_CONFIG_DIR=/etc/scanbd? should not happen (s. ReadMe), but
>>
>> SANE_CONFIG_DIR=/etc/scanbd scanimage -L
>>
>> should list the scanner.
> 
> See above, "scanimage -L" no longer worked.  sane-find-scanner does not
> seem to affected by SANE_CONFIG_DIR at all.  Why did you ask?

because it is essential that it works!

$ SANE_CONFIG_DIR=/etc/scanbd scanimage -L

must list the scanner and must not(!) use the net-backend (-> poosible loop)

> 
>>>> Before I attempted to change things, /etc/scanbd/dll.conf contained
>>>> ONLY the net backend 
>>
>> wrong
>>
>>>> and /etc/sane.d/dll.conf contained a whole bunch
>>>> of backends including genesys and net.
>>
>> wrong: should only contain net backend
> 
> Of course.  I know this now.  But again, see above, when I did the
> configuration according to the (long) README the situation so far only
> got worse.
> 
> I am currently trying to get network scanning with saned working which
> seems to be a prerequisite step before for scanbd config (except that of
> course, scanbd works fine from the command-line, go figure).

but don't start saned from init, it is started from scanbd


> Couple of questions.  Should I see scanbm or "scanbd -m" in the list of
> running processes?  What I get here is "/usr/sbin/scanbd -c
> /etc/scanbd/scanbd.conf".  

Thats ok.

> Am I correct to assume that scanning over the
> network (even if the network is only 127.0.0.1) is a prerequisite before
> everything else?

yes (but see above), thats the reason to only include the net-backend in
/etc/sane.d/dll.conf

> I have now temporarily set /etc/sane.d/dll.conf to contain only the net
> backend.  net.conf in the same directory defines saned hosts at
> localhost and 127.0.0.1.  "nmap localhost" shows the sane-port at 6566
> to be open.  

Looks like saned ist started directly or via inetd, that would wrong.

But "SANE_CONFIG_DIR=/etc/sane.d scanimage -L" either
> crashes outright or does not find any scanner.  

If scanbd is running at the very same moment, that is expected! The
basis test to see if the scanner is recognized can only run if scanbd
isn't running at the same moment, because both would try to open the
device, and thats not possible (libsane-limitation).


> The strange thing having
> both the net and genesys backend in there results in either a crash or
> 
> $ SANE_CONFIG_DIR=/etc/sane.d scanimage -L
> device `genesys:libusb:002:011' is a Canon LiDE 35/40/50 flatbed scanner
> device `net:127.0.0.1:genesys:libusb:002:011' is a Canon LiDE 35/40/50
> flatbed scanner
> device `net:localhost:genesys:libusb:002:011' is a Canon LiDE 35/40/50
> flatbed scanner

If scanbd isn't running, nothing should be found, iff scanbd is running,
only the net:localhost entry should be found.

> 
> I am starting to wonder if the version 1.0.23 in trusty is simply
> terribly buggy to the point of being unusable.

I don't think so! (see above)


-- 
Wilhelm
w.meier at unix.net