[cups] Still conceptually possible to use SCSI backend in latest CUPS?

[Protea Wines Japan]

On Fri, Feb 19, 2021 at 4:01 PM Johannes Meixner <jsmeix at suse.de> wrote:

>
> Hello,
>
> On 2021-02-18 18:20, Protea Wines Japan wrote (excerpt):
> > Is it conceptually still possible to compile
> > the old scsi.c backend in CUPS 1.2
>
> conceptually a CUPS backend is an arbitrary program
> that gets data and sends it to a recipient, see
>
> https://en.opensuse.org/SDB:Using_Your_Own_Backends_to_Print_with_CUPS


Many thanks Johannes, I could tell from your document that there is nothing
specifically preventing the SCSI backend from being used, provided it uses
the right commands to the SCSI high-level driver.
I spent some time reading up on the SCSI subsystem in linux again, and the
sg3 high-level driver.
It looks like the scsi.c file should still be compilable and usable as is,
since it uses the sg_io_hdr which is what is currently used in sg3 also.

I ran into a problem with compiling though. I wonder if you or anyone
familiar with the current (forked?) CUPS code can help:

hase at hase:~/src/CUPS-SCSI-Backend$ gcc -o scsi-backend scsi.c
In file included from scsi.c:59:
/usr/include/cups/i18n.h:18:12: fatal error: config.h: No such file or
directory
   18 | #  include "config.h"
      |            ^~~~~~~~~~
compilation terminated.

It looks like the CUPS header file config.h is missing. I am not sure where
I should find this, I have all available development packages installed I
think. Even downloading the Debian CUPS source package does not find this
file although there are 2 config.h files in subsystem source trees:
hase at hase:~/src/CUPS-SCSI-Backend/cups-2.3.3op2$ find . -name config.h
./vcnet/config.h
./xcode/config.h

As for linux, there are 2 config.h files in the source tree (none in the
common headers):
hase at hase:~/src/CUPS-SCSI-Backend/cups-2.3.3op2$ find
/usr/src/linux-headers-5.10.0-3-amd64 -name config.h
/usr/src/linux-headers-5.10.0-3-amd64/include/config/snd/intel/dsp/config.h
/usr/src/linux-headers-5.10.0-3-amd64/include/config/pci/lockless/config.h

Best regards,
Gernot Hassenpflug