## PHP extension seg-faulting

29th March 2021

Task at hand: Call Cobol (=GnuCOBOL) from PHP. I used FFI for this: <?php $cbl = FFI::cdef("int phpsqrt(void); void cob_init_nomain(int,char**); int cob_tidy(void);", "/srv/http/phpsqrt.so");$ffj0 = FFI::cdef("double j0(double);",…

15th March 2021

Problem at hand: There are multiple machines running SSHGuard. Each of these machines accumulates different sets of blacklists. Task: Add disjoint IP addresses from one machine to another machine's blacklist. 1. Copy from "master" machine: scp -p master:/var/db/sshguard/blacklist.db…

## Lesser Known Static Site Generators

7th March 2021

Well known static site generators are Hugo (written in Go), Pelican (written in Python), Grav (written in PHP), or Eleventy (written in JavaScript). For a list of static site generators see Jamstack (322 generators listed) or Static Site Generators (460 generators listed). The following three…

## Testing J-Pilot feature-gtk3 branch

2nd March 2021

J-Pilot 1.8 still relies on GTK+ 2, which is heading towards planned deprecation. The entire work to migrate to GTK+ 3 is done by volunteers, Judd Montgomery and David Malia. This post is about testing this new experimental branch feature-gtk3 from GitHub. Installing this branch is…

## Analysis And Usage of SSHGuard

28th February 2021

To ban annoying ssh access to your Linux box you can use fail2ban. Or, alternatively, you can use SSHGuard. SSHGuard's installed size is 1.3 MB on Arch Linux. Its source code, including all C-files, headers, manuals, configuration, and makefiles is 8 KLines. In contrast, for fail2ban just the…

## ssh as SOCKS server

21st February 2021

Assume three computers A, B, and C. A can connect to B via ssh, but A cannot connect to C, but B can connect to C. A -> B -> C On A open ssh as SOCKS-server with ssh -N -D 9020 user@B Now on A one can use brave --proxy-server="socks5://localhost:9020" The browser will then show…

## Poisson Log-Normal Distributed Random Numbers

9th February 2021

Task at hand: Generate random numbers which follow a lognormal distribution, but this drawing is governed by a Poisson distribution. I.e., the Poisson distribution governs how many lognormal random values are drawn. Input to the program are $$\lambda$$ of the Poisson distribution, modal value and…

## Performance comparison Ryzen vs. Intel vs. Bulldozer vs. ARM

1st February 2021