Engineering and technology notes

Reverse Proxy Configuration — Nextcloud 11 Server Administration Manual 11 alpha documentation

<?php
$CONFIG = array (
  "trusted_proxies"   => ['10.0.0.1'],
  "overwritehost"     => "ssl-proxy.tld",
  "overwriteprotocol" => "https",
  "overwritewebroot"  => "/domain.tld/nextcloud",
  "overwritecondaddr" => "^10\.0\.0\.1$",
);

https://docs.nextcloud.com/server/11/admin_manual/configuration_server/reverse_proxy_configuration.html#example

Reverse Proxy Configuration — Nextcloud 11 Server Administration Manual 11 alpha documentation was last modified: March 29th, 2020 by Jovan Stosic

Canon Printers and CUPS: ARM drivers availabile?

Re: Canon Printers and CUPS: ARM drivers availabile?

Wed Feb 22, 2017 5:17 pm

Update: The canon imageCLASS MF4570dn printer now prints from CUPS on the raspberry pi. I originally learned about this process from here: https://www.lhinderberger.de/pi/2016/01 … ivers.html and here http://orange314.com/Run_x86_code_on_OPI

First you need to have binfmt-support and qemu-i386 installed to run x86 drivers, binaries, etc:

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sudo apt-get install binfmt-support qemu-user

Enable the kernel to automatically hand x86 programs to qemu:

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sudo echo ':i386:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff:/usr/bin/qemu-i386-static:' > /proc/sys/fs/binfmt_misc/register

Then you’re going to create the default directory for the qemu i386 library files and link it to the other default directory for qemu i386 libraries:

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mkdir -p /etc/qemu-binfmt/i386
ln -s /etc/qemu-binfmt/i386 /usr/gnemul/qemu-i386

Next, you’ll install the 32-bit driver common and ufr2 deb files manually:

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ar x cndrvcups-common_3.70-1_i386.deb data.tar.xz && mkdir common-data && mv data.tar.xz common-data/data.tar.xz
ar x cndrvcups-common_3.70-1_i386.deb control.tar.xz && tar xvf control.tar.xz ./postinst && mv postinst common-data/postinst.sh && chmod 777 postinst.sh
ar x cndrvcups-ufr2-us_3.30-1_i386.deb data.tar.xz && mkdir ufr2-data && mv data.tar.xz ufr2-data/data.tar.xz 
ar x cndrvcups-ufr2-us_3.30-1_i386.deb control.tar.xz && tar xvf control.tar.xz ./postinst && mv postinst ufr2-data/postinst.sh && chmod 777 postinst.sh
sudo su
pushd common-data
tar xvC /etc/qemu-binfmt/i386 -f data.tar.xz ./lib ./usr/lib 
tar xvC / -f data.tar.xz ./usr/bin ./usr/include ./usr/share ./usr/lib/cups ./etc 
popd
pushd ufr2-data
tar xvC /etc/qemu-binfmt/i386 -f data.tar.xz ./lib ./usr/lib 
tar xvC / -f data.tar.xz ./usr/bin ./usr/include ./usr/share ./usr/lib/cups ./etc 
popd
./common-data/postinst.sh
./ufr2-data/postinst.sh

Now, the fun part – manually downloading and installing all the dependency libraries. Here’s how to extract one library manually to our default library folder:

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pushd /tmp && mkdir libraryname && cd libraryname
wget http://url-to-tar.gz-file
ar x tar.gz-file data.tar.xz --OR-- ar x tar.gz-file data.tar.gz
tar xvC /etc/qemu-binfmt/i386 -f data.tar.xz ./etc ./lib ./usr/lib --OR -- tar xvC /etc/qemu-binfmt/i386 -f data.tar.gz ./etc ./lib ./usr/lib
popd

Finally, since the proprietary cups filter pstoufr2cpca calls ghostscript with an x86 driver/shared library, we also need to download and install the x86 version of ghostscript and all of it’s library dependencies as well following the convention above. You may be wondering, “I have two different copies of the ghostscript program now. How do I tell pstoufr2cpca to use the x86 one instead of the arm one?” Not so lucky for us, pstoufr2cpca calls the ghostscript program by full path “/usr/bin/gs”. We’ll need to create a bash script that replaces “/usr/bin/gs” and allow the bash script to call the correct ghostscript program. Here’s the contents of the bash script that I made. I renamed the ghostscript programs to “gs-i386” and “gs-arm” and put them in /usr/bin. This script must also be given execute permission by using chmod.

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#!/bin/bash
PARENT_COMMAND=$(ps --no-headers -o command $PPID)
if [[ $PARENT_COMMAND == *"pstoufr2"* ]]; then
        /usr/bin/gs-i386 "$@"
else
        /usr/bin/gs-arm "$@"
fi

You can test the process that cups uses to print a test page by issuing the commands manually. The last command is the important command. If this runs successfully and pstoout.out contains binary code, your printer will print this document.

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export PPD=/usr/share/cups/model/CNCUPSMF4500ZS.ppd
/usr/lib/cups/filter/bannertopdf 1 me '' 1 '' < /usr/share/cups/data/testprint > bannertopdf.pdf
/usr/lib/cups/filter/pdftopdf 1 me '' 1 '' < bannertopdf.pdf > pdftopdf.pdf
/usr/lib/cups/filter/pdftops 1 me '' 1 '' < pdftopdf.pdf > pdftops.ps
/usr/lib/cups/filter/pstoufr2cpca 1 me '' 1 '' < pdftops.ps > pstoout.out

If this produces errors, you’ll need to check if qemu is running the cups filter, is the correct ghostscript program running, and do you have all the dependency x86 libraries installed, etc.

Canon Printers and CUPS: ARM drivers availabile? was last modified: March 27th, 2020 by Jovan Stosic