Syntax highlighting in pagers (eg. like less) using GNU source-highlight
Mar 21st, 2021 by miki

EDIT 2021-08-31: add section about possible unexpected change of behaviour when using the simple (global) setup (fx. git)

There is this nifty OS project, GNU, which has this nifty piece of software for syntax highlighting, source-highlight (aka. src-highlite), together with which is distributed this nifty shell script,, meant for piping arbitrary text through the highlighter selecting and applying a sensible highlight language definition, before being paged in some nifty pager which is able to interpret ANSI escape codes (ISO/IEC 6429 or ECMA-48, previously ANSI X3.64/FIPS PUB 86) like fx. the nifty and ubiquitous less.

Sadly, even after having installed less and source-highlight on modern Ubuntu and Debian systems they are not inter-operating by default. You’d have to feel the itch of syntax highlighting, discover source-highlight and dig its documentation to find out about said script.

TL;DR – quick and simple setup

Below is a quick two-line shell HOW-TO which sets up environment variables for the current user to enable auto-detection of language and subsequent syntax highlighting pr. default in less using GNU source-highlight (here done on Ubuntu 20.04 LTS, should behave similarly on Debian and derived distributions);

$ sudo apt install source-highlight
$ echo -e "\nexport LESSOPEN=\"| /usr/share/source-highlight/ %s\"\nexport LESS=' -R '" >> ~/.bash_aliases


This setup will make fx. some C source code display as below in less.

environment set up for less to enable ANSI color codes and pass any text through source-highlighter for potential ANSI escape code addition

less showing highlighted C code, auto-detected and highlighted by GNU source-highlighter

Complicating TL;DR

One caveat of this global setup being active for any invocation of less, is that most programs will behave accordingly and some maybe different from expectations.

Notably, using the git command line client with the above setup will make git refrain from setting a default LESS=FRX environment (see core.pager of man git config) when invoking less. This turns off the less features “quit-if-one-screen” (F) and “no-init” (X) (see OPTIONS of man less) which usually makes less invisible in git contexts unless paging is actually needed. This could cause confusion for some, making git seemingly take over the terminal on even 1 line outputs (see this bug report on GNU src-hilite and my comment detailing the above).

One solution to this would of course be to add “FX” to the environment, another is making a little more elaborate, more conservative and less transparent setup, as below.

For the conservative

If you’d still like to have a “plain less” not messing with and amending you text unless you ask it to, you could make an alias to use specifically when you want syntax highlighting. Put these somewhere interpreted by you shell (for bash fx. ~/.bash_aliases);

# syntax highlight in less
alias lesssh="LESSOPEN='|/usr/share/source-highlight/ %s' LESS=' -R ' less"
function lessurl() { wget -O- -q $1 |source-highlight -f esc -s html |less -R; }

Line two is a bonus shell function pulling some HTML from a webserver using wget, adding syntax highlighting and showing it in less.

Digging deeper

For the brave, take a tour of the “info source-highlight” (or “man source-highlight”) manuals (also here) to become familiar with the tool. You can use it anywhere you’d like some colour on arbitrary text and where color are supported in various ways and encodings, for example HTML and latex;

source-highlight adding color encoding to C code using HTML and latex encoding

If you are a programmer wanting to add highlighting features to you own application, the command line utilities are building on a highlighting library which you can utilise (API documentation here).

GitHub CLI on Ubuntu LTS (16.04 & 18.04)
Mar 4th, 2020 by miki

Inspired by a John Sullivan (of FSF) tweet asking about opinions on the new and shiny MS(TM) GitHub(TM) CLI(TM) tool named “gh”(TM) I wanted to try it out on one of my Ubuntu LTS systems (16.04).

I’ve always disliked the proprietary and centralised monoculture of github, especially after that thing with MS, so I’ve mostly avoided using the service for code I produce myself. If interested in independence and decentralisation maybe you should read up on that long fabled subject? Thus I’ve never even tried the predecessor “hub”(TM) tool (main page), and exactly how it differs from this new “CLI” thing is not obviously apparent from the communications.

Nevertheless, the “gh” tool, officially dubbed  GitHub CLI, being distributed under MIT license and written in go(lang) (afterwards, found out that this is indeed also applicable to the predecessing “hub” tool) made me curious enough to go see what they’re up to. Maybe its not that sinister a plot and they really just want to improve the independent and freely available mechanisms for source code storage, distribution and maintenance (I wish)?


A fairly recent (2019-09) version of go, >=1.13, is required so some gymnastics are needed to make stuff work on older distros like Ubuntu’s LTS (with 5 years support from Canonical). Anyway, this is what I did to build a useable “gh” ELF executable (20 MiB!, se below), this is from source, no precompiled stuff, no snaps. It was done on Ubuntu 16.04 (xenial) but I’ve been somewhat careful to inspect that things ought to be good for 18.04 (bionic) too. Non-essential output from the commands is largely discarded here. See Gory Details section below for the full monty.

Add go PPA & install packages

$ sudo add-apt-repository ppa:longsleep/golang-backports
$ sudo apt update
$ sudo apt install golang
$ go version
go version go1.13.4 linux/amd64

Clone repo & build

$ cd
$ git clone .githubcli
$ cd .githubcli
$ make

Setup PATH & test

$ echo 'export PATH="$HOME/.githubcli/bin:$PATH"' >> ~/.bash_profile
$ bash --login
$ gh
Work seamlessly with GitHub from the command line.

GitHub CLI is in early stages of development, and we'd love to hear your
feedback at <>

  gh [command]

Available Commands:
  help        Help about any command
  issue       Create and view issues
  pr          Create, view, and checkout pull requests
  repo        Create, clone, fork, and view repositories

      --help              Show help for command
  -R, --repo OWNER/REPO   Select another repository using the OWNER/REPO format
      --version           Show gh version

Use "gh [command] --help" for more information about a command.
subcommand is required

Trying it out

Randomly picked one of my few github repos, it contains some js experiments on parsing NMEA formatted coordinates, rather uninterestingly empty.


user@host:~$ gh repo clone mikini/coordinates 
Notice: authentication required
Press Enter to open in your browser... 

<auth session in browser>

Authentication complete. Press Enter to continue...

Cloning into 'coordinates'...
remote: Enumerating objects: 10, done.
remote: Total 10 (delta 0), reused 0 (delta 0), pack-reused 10
Unpacking objects: 100% (10/10), done.
Checking connectivity... done.

An ordinary OAuth request was spawned for authentication on The javascript executed in the browser seemed to interact with the gh tool through a local TCP connection on localhost:45454 which was the redirection target on authorisation (URL parameter: “redirect_uri=http://localhost:45454/callback”). The socket was rightfully not bound after the authentication had succeeded but this is definitely an attack vector, albeit hopefully only for locally running processes.

Listing issues & prs

user@host:~$ cd coordinates/
user@host:~$:~/coordinates$ gh issue list

Issues for mikini/coordinates

There are no open issues
miki@vcas-miki2:~/coordinates$ gh pr view
no open pull requests found for branch "master"

Creating issues

miki@vcas-miki2:~/coordinates$ gh issue create

Creating issue in mikini/coordinates

? Title Testing gh
? Body <Received>
? What's next? Preview in browser
Opening in your browser.

miki@vcas-miki2:~/coordinates$ gh issue create

Creating issue in mikini/coordinates

? Title Testing gh tool
? Body <Received>
? What's next? [Use arrows to move, type to filter]
> Preview in browser

On the first issue creation interaction I selected “preview in browser” which opened a draft issue in the browser, and dumped me back into the shell on the command line. The second interaction actually resulted in #1.

Gory Details

PPA options

The golang-backports PPA is maintained independently by Simon Eisenmann (credits: ~longsleep, @github, and carries packages up to:

There’s also an official PPA from the golang project (~gophers) which however only carries packages up to 1.11 for both.

Full (mostly) installation dump

Add go PPA, install packages

user@host:~$ sudo add-apt-repository ppa:longsleep/golang-backports
Golang 1.8, 1.9, 1.10, 1.11, 1.12, 1.13 and 1.14 PPA for Ubuntu
 More info:
Press [ENTER] to continue or ctrl-c to cancel adding it

gpg: keyring `/tmp/tmpvnuym97a/secring.gpg' created
gpg: keyring `/tmp/tmpvnuym97a/pubring.gpg' created
gpg: requesting key 56A3D45E from hkp server
gpg: /tmp/tmpvnuym97a/trustdb.gpg: trustdb created
gpg: key 56A3D45E: public key "Launchpad PPA for Simon Eisenmann" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)

user@host:~$ sudo apt update
Hit:1 xenial InRelease
Get:2 xenial-updates InRelease [109 kB] 
Get:37 xenial-security/universe DEP-11 64x64 Icons [194 kB]
Get:38 xenial-security/multiverse amd64 DEP-11 Metadata [2.468 B]
Fetched 7.614 kB in 3s (2.346 kB/s) 
Reading package lists... Done
Building dependency tree 
Reading state information... Done
419 packages can be upgraded. Run 'apt list --upgradable' to see them.

user@host:~$ apt list --upgradeable golang -a
Listing... Done
golang/xenial,xenial 2:1.13~1longsleep1+xenial all [upgradable from: 2:1.6-1ubuntu4]
golang/xenial,xenial,now 2:1.6-1ubuntu4 all [installed,upgradable to: 2:1.13~1longsleep1+xenial]


user@host:~$ sudo apt install golang
Reading package lists... Done
Building dependency tree 
Reading state information... Done
The following packages were automatically installed and are no longer required:
golang-1.6 golang-1.6-doc golang-1.6-go golang-1.6-src
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
golang-1.13 golang-1.13-doc golang-1.13-go golang-1.13-src golang-doc golang-go golang-src
Recommended packages:
The following NEW packages will be installed
golang-1.13 golang-1.13-doc golang-1.13-go golang-1.13-src
The following packages will be upgraded:
golang golang-doc golang-go golang-src
4 to upgrade, 4 to newly install, 0 to remove and 413 not to upgrade.
Need to get 60,2 MB of archives.
After this operation, 322 MB of additional disk space will be used.
Do you want to continue? [Y/n] 
Get:1 xenial/main amd64 golang-1.13-src amd64 1.13.4-1longsleep1+xenial [12,7 MB]
Get:2 xenial/main amd64 golang-1.13-go amd64 1.13.4-1longsleep1+xenial [44,9 MB]
Get:3 xenial/main amd64 golang-1.13-doc all 1.13.4-1longsleep1+xenial [2.542 kB]
Get:4 xenial/main amd64 golang-1.13 all 1.13.4-1longsleep1+xenial [25,2 kB]
Get:5 xenial/main amd64 golang-src amd64 2:1.13~1longsleep1+xenial [3.838 B]
Get:6 xenial/main amd64 golang-go amd64 2:1.13~1longsleep1+xenial [23,0 kB]
Get:7 xenial/main amd64 golang-doc all 2:1.13~1longsleep1+xenial [3.880 B]
Get:8 xenial/main amd64 golang all 2:1.13~1longsleep1+xenial [3.826 B]
Fetched 60,2 MB in 5s (10,8 MB/s) 
Selecting previously unselected package golang-1.13-src.
(Reading database ... 460737 files and directories currently installed.)
Preparing to unpack .../golang-1.13-src_1.13.4-1longsleep1+xenial_amd64.deb ...
Unpacking golang-1.13-src (1.13.4-1longsleep1+xenial) ...
Selecting previously unselected package golang-1.13-go.
Preparing to unpack .../golang-1.13-go_1.13.4-1longsleep1+xenial_amd64.deb ...
Unpacking golang-1.13-go (1.13.4-1longsleep1+xenial) ...
Selecting previously unselected package golang-1.13-doc.
Preparing to unpack .../golang-1.13-doc_1.13.4-1longsleep1+xenial_all.deb ...
Unpacking golang-1.13-doc (1.13.4-1longsleep1+xenial) ...
Selecting previously unselected package golang-1.13.
Preparing to unpack .../golang-1.13_1.13.4-1longsleep1+xenial_all.deb ...
Unpacking golang-1.13 (1.13.4-1longsleep1+xenial) ...
Preparing to unpack .../golang-src_2%3a1.13~1longsleep1+xenial_amd64.deb ...
Unpacking golang-src (2:1.13~1longsleep1+xenial) over (2:1.6-1ubuntu4) ...
Preparing to unpack .../golang-go_2%3a1.13~1longsleep1+xenial_amd64.deb ...
Unpacking golang-go (2:1.13~1longsleep1+xenial) over (2:1.6-1ubuntu4) ...
Preparing to unpack .../golang-doc_2%3a1.13~1longsleep1+xenial_all.deb ...
Unpacking golang-doc (2:1.13~1longsleep1+xenial) over (2:1.6-1ubuntu4) ...
Preparing to unpack .../golang_2%3a1.13~1longsleep1+xenial_all.deb ...
Unpacking golang (2:1.13~1longsleep1+xenial) over (2:1.6-1ubuntu4) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up golang-1.13-src (1.13.4-1longsleep1+xenial) ...
Setting up golang-1.13-go (1.13.4-1longsleep1+xenial) ...
Setting up golang-1.13-doc (1.13.4-1longsleep1+xenial) ...
Setting up golang-1.13 (1.13.4-1longsleep1+xenial) ...
Setting up golang-src (2:1.13~1longsleep1+xenial) ...
Setting up golang-go (2:1.13~1longsleep1+xenial) ...
Setting up golang-doc (2:1.13~1longsleep1+xenial) ...
Setting up golang (2:1.13~1longsleep1+xenial) ...

user@host:~$ go version
go version go1.13.4 linux/amd64

Clone repo & build

user@host:~$ git clone .githubcli
Cloning into '.githubcli'...
remote: Enumerating objects: 168, done.
remote: Counting objects: 100% (168/168), done.
remote: Compressing objects: 100% (100/100), done.
remote: Total 5577 (delta 93), reused 122 (delta 67), pack-reused 5409
Receiving objects: 100% (5577/5577), 7.53 MiB | 2.61 MiB/s, done.
Resolving deltas: 100% (3269/3269), done.
Checking connectivity... done.

user@host:~$ cd .githubcli
user@host:~/.githubcli (master=)$ make
go: downloading v0.0.0-20191202100458-e7afc7fbc510
go: downloading v1.1.0
go: downloading v0.1.6
go: downloading v0.0.6
go: downloading v3.0.0-20200121175148-a6ecf24a6d71
go: downloading v0.0.12
go: downloading v0.3.2
go: extracting v1.1.0
go: extracting v0.1.6
go: extracting v0.0.0-20191202100458-e7afc7fbc510
go: extracting v0.0.6
go: extracting v0.0.12
go: downloading v0.0.0-20200223170610-d5e6a3e2c0ae
go: downloading v0.0.0-20200219234226-1ad67e1f0ef4
go: downloading v0.0.0-20170206155736-9520e82c474b
go: downloading v1.9.0
go: extracting v3.0.0-20200121175148-a6ecf24a6d71
go: downloading v1.2.0
go: downloading v1.0.5
go: downloading v2.0.7
go: downloading v0.0.0-20180428030007-95032a82bc51
go: downloading v0.1.1-0.20200304134224-7e5c90143acc
go: extracting v0.0.0-20170206155736-9520e82c474b
go: extracting v1.0.5
go: extracting v1.2.0
go: downloading v2.2.8
go: downloading v2.0.0
go: downloading v0.0.4
go: extracting v0.0.0-20180428030007-95032a82bc51
go: extracting v1.9.0
go: extracting v2.0.7
go: downloading v1.7.0
go: extracting v0.1.1-0.20200304134224-7e5c90143acc
go: downloading v1.1.24
go: downloading v1.0.2
go: extracting v2.2.8
go: extracting v0.0.4
go: downloading v0.0.4
go: downloading v0.1.0
go: extracting v1.7.0
go: extracting v1.0.2
go: extracting v2.0.0
go: extracting v0.0.0-20200223170610-d5e6a3e2c0ae
go: extracting v0.1.0
go: extracting v0.0.4
go: downloading v0.0.0-20200219183655-46282727080f
go: extracting v1.1.24
go: downloading v0.7.2-0.20200304075647-34d9c7143bf5
go: downloading v0.0.8
go: downloading v0.4.0
go: downloading v2.0.1
go: extracting v0.0.0-20200219234226-1ad67e1f0ef4
go: extracting v0.0.8
go: extracting v2.0.1
go: downloading v1.0.0
go: extracting v0.7.2-0.20200304075647-34d9c7143bf5
go: extracting v1.0.0
go: extracting v0.4.0
go: downloading v1.2.0
go: downloading v1.0.3
go: downloading v0.0.0-20190703233501-fc88cf888a3f
go: downloading v0.0.0-20160403171240-cbb64ac3d964
go: extracting v0.3.2
go: extracting v0.0.0-20190703233501-fc88cf888a3f
go: extracting v0.0.0-20160403171240-cbb64ac3d964
go: extracting v0.0.0-20200219183655-46282727080f
go: extracting v1.0.3
go: extracting v1.2.0
go: finding v0.0.6
go: finding v2.0.7
go: finding v0.0.4
go: finding v0.0.0-20191202100458-e7afc7fbc510
go: finding v0.0.0-20170206155736-9520e82c474b
go: finding v3.0.0-20200121175148-a6ecf24a6d71
go: finding v1.0.5
go: finding v1.2.0
go: finding v1.1.0
go: finding v1.9.0
go: finding v0.3.2
go: finding v2.0.0
go: finding v0.1.1-0.20200304134224-7e5c90143acc
go: finding v0.0.0-20180428030007-95032a82bc51
go: finding v0.1.6
go: finding v2.2.8
go: finding v2.0.1
go: finding v0.0.12
go: finding v1.7.0
go: finding v0.0.0-20200219234226-1ad67e1f0ef4
go: finding v0.4.0
go: finding v0.0.0-20200223170610-d5e6a3e2c0ae
go: finding v1.0.0
go: finding v1.1.24
go: finding v0.7.2-0.20200304075647-34d9c7143bf5
go: finding v0.0.0-20190703233501-fc88cf888a3f
go: finding v1.2.0
go: finding v1.0.3
go: finding v0.1.0
go: finding v1.0.2
go: finding v0.0.0-20160403171240-cbb64ac3d964
go: finding v0.0.4
go: finding v0.0.8
go: finding v0.0.0-20200219183655-46282727080f
user@host:~/.githubcli (master=)$ 

Cursory inspection of exec

user@host:~/.githubcli (master=)$ ls -l bin/gh
-rwxrwxr-x 1 user user 21097487 Mar  4 18:03 bin/gh
user@host:~/.githubcli (master=)$ 

user@host:~/.githubcli (master=)$ file bin/gh
bin/gh: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/l, not stripped
user@host:~/.githubcli (master=)$ 

user@host:~/.githubcli (master=)$ ldd bin/gh =>  (0x00007ffdc4329000) => /lib/x86_64-linux-gnu/ (0x00007fb1018c2000) => /lib/x86_64-linux-gnu/ (0x00007fb1014f8000)
	/lib64/ (0x00007fb101adf000)
user@host:~/.githubcli (master=)$ 

user@host:~/.githubcli (master=)$ nm -D bin/gh
                 U abort
00000000004fd140 T _cgo_panic
000000000045bf10 T _cgo_topofstack
00000000004fd190 T crosscall2
                 U __errno_location
                 U __fprintf_chk
                 U fputc
                 U free
                 U freeaddrinfo
                 U fwrite
                 U gai_strerror
                 U getaddrinfo
                 U getnameinfo
                 U malloc
                 U mmap
                 U munmap
                 U nanosleep
                 U pthread_attr_destroy
                 U pthread_attr_getstacksize
                 U pthread_attr_init
                 U pthread_cond_broadcast
                 U pthread_cond_wait
                 U pthread_create
                 U pthread_detach
                 U pthread_mutex_lock
                 U pthread_mutex_unlock
                 U pthread_sigmask
                 U setenv
                 U sigaction
                 U sigaddset
                 U sigemptyset
                 U sigfillset
                 U sigismember
                 U __stack_chk_fail
                 U stderr
                 U strerror
                 U unsetenv
                 U __vfprintf_chk
user@host:~/.githubcli (master=)$ 

Setup PATH & test

user@host:~/.githubcli (master=)$ cd
user@host:~$ echo 'export PATH="$HOME/.githubcli/bin:$PATH"' >> ~/.bash_profile
user@host:~$ bash --login
user@host:~$ gh
Work seamlessly with GitHub from the command line.

GitHub CLI is in early stages of development, and we'd love to hear your
feedback at <>

  gh [command]

Available Commands:
  help        Help about any command
  issue       Create and view issues
  pr          Create, view, and checkout pull requests
  repo        Create, clone, fork, and view repositories

      --help              Show help for command
  -R, --repo OWNER/REPO   Select another repository using the OWNER/REPO format
      --version           Show gh version

Use "gh [command] --help" for more information about a command.
subcommand is required
Ubuntu 18.04 Tweaks for a 16.04 User
Jun 24th, 2019 by miki

This post will detail some stuff I’ve done to a plain Ubuntu 18.04 Desktop (bionic) to make me feel a little more at home in the transition from my daily driver for years the 16.04 release using Canoncial’s Unity as the primary desktop interface to the GNOME Shell of 18.04. Canonical abandoned the former after shifting focus from the convergence and personal device market to cloud and IoT in 2017 leaving development of its mobile OS, Ubuntu Touch which Unity is a part of, to the community formed UBports project (Unity8 is now known as Lomiri). I’ve been putting off this transition exactly because I knew it would require me to make some tweaks to my daily routines, but this system is not one I use on a daily basis so it will make the transition a gentle ride.

The intention is to update this as the experience progresses.

EDIT 2021-08-25: clean up and publish dormant draft post

Browsing GNOME Extensions

To be able to install GNOME Extensions directly from a browser while perusing the directory at, add the GNOME Shell Integration extension/add-on to your browser (Firefox add-on, Chrome Web Store), then install the Integration extension in GNOME to communicate with the browser extension:

sudo apt install chrome-gnome-shell

After this you can go to to see, configure and update installed extensions.

Useful GNOME Extensions

Time Keeping

World/Alarm/Stopwatch/Timer application

GNOME includes a nice Clock application which is available in the package repository but not installed by default;

sudo apt install gnome-clocks

Installing the Alarm Clock extension described above, will also show the application’s alarms in the notification area.

Notification bar

I like both the date and seconds to be displayed in the head of the desktop, so to format the text a couple of extensions are available;

Itch: eog core dump on Galaxy 7 panorama image
Jun 10th, 2019 by miki

  • Took some photos with my Galaxy 7. Some were panoramas.
  • EOG crashed while loading them.
  • Memory was low.
  • Maybe related to previously experienced missing EOI marker issue with Samsung camera application.

Will investigate later and amend the post (promise!).

Commandline Dump

$ free; find . -size +25M -exec bash -c 'ls -l {}; eog {}; echo' \;; free
              total        used        free      shared  buff/cache   available
Mem:        7746692     5767656      843228      317764     1135808     1271048
Swap:       7950332     5113012     2837320
-rw-rw-r-- 1 miki miki 39926496 Jun 10 19:25 ./20190609_184124.jpg

** (eog:23320): CRITICAL **: eog_reload_plugin_activate: assertion 'G_IS_MENU (model)' failed
eog: ../../../../src/cairo-xlib-surface-shm.c:619: _cairo_xlib_shm_pool_create: Assertion `*ptr != ((void *)0)' failed.
bash: line 1: 23320 Aborted                 (core dumped) eog ./20190609_184124.jpg

-rw-rw-r-- 1 miki miki 38286099 Jun 10 19:26 ./20190609_183714.jpg

** (eog:23332): CRITICAL **: eog_reload_plugin_activate: assertion 'G_IS_MENU (model)' failed
eog: ../../../../src/cairo-xlib-surface-shm.c:619: _cairo_xlib_shm_pool_create: Assertion `*ptr != ((void *)0)' failed.
bash: line 1: 23332 Aborted                 (core dumped) eog ./20190609_183714.jpg

-rw-rw-r-- 1 miki miki 36181801 Jun  9 17:13 ./20190609_160437.jpg

** (eog:23343): CRITICAL **: eog_reload_plugin_activate: assertion 'G_IS_MENU (model)' failed

** (eog:23343): CRITICAL **: eog_reload_plugin_deactivate: assertion 'G_IS_MENU (menu)' failed

-rw-rw-r-- 1 miki miki 39059177 Jun 10 19:25 ./20190609_184146.jpg

** (eog:23354): CRITICAL **: eog_reload_plugin_activate: assertion 'G_IS_MENU (model)' failed
eog: ../../../../src/cairo-xlib-surface-shm.c:619: _cairo_xlib_shm_pool_create: Assertion `*ptr != ((void *)0)' failed.
bash: line 1: 23354 Aborted                 (core dumped) eog ./20190609_184146.jpg

              total        used        free      shared  buff/cache   available
Mem:        7746692     5773448      495604      659944     1477640      922956
Swap:       7950332     5112700     2837632


[Danish] S&S: Android-x86 og Chromebook
Jun 8th, 2019 by miki

Lidt flere dråber i Spørgsmål&Svar-kategorien fra Facebook.

Når jeg endelig forvilder mig derind, og går på opdagelse i de tekniske grupper, ender det ofte med at får jeg skrevet en fristil i forsøget på at hjælpe.

Denne gang en snak om Android på “PC”, og basale digitale processeringsbehov for den almindelige dansker.


Stillet i gruppen “Danske Android Brugere “:

Er der nogen som ved, om man kan få en pc med Android system?


Mit svar:

Som andre omtaler, kan der fås en uofficiel variant af det frie styresystem Android til x86-arkitekturen (den gængse Intel/AMD-baserede computer kendt som “personlig computer”).

Det projekt lever på Installationsvejledning på engelsk er på Man kan både installere som multiboot på samme disk som et eksisterende operativsystem, starte fra en ekstern disk (USB-medie, cd/dvdrom e.l.) eller evt. køre i en virtuel maskine på et eksisterende operativsystem (VirtualBox,QEMU/KVM, VMware Player/Workstation).

Jeg har kun erfaring med livedisk boot fra USB og VM, og der synes jeg ikke altid tingene spiller perfekt, så forvent ikke en helt problemfri oplevelse.

“Android på PC” er på kanten af noget understøttet, hvor man ofte er på egen hånd. Nogle af folkene bag Andoid-x86 forsøgte at lave en kommerciel forretning på det, hvor det var tanken at sælge det som færdige hardwareenheder, RemixOS –, men det gik ikke så godt og er lukket ned igen.

Hvis behovet bare er “en bærbar computer uden for meget vrøvl”, så er en færdig Chromebook med Chrome OS (der ligesom Android også er bygget på GNU/Linux) eller noget af det der dyre Frugt-udstyr nok det mest tilgængelige (men jeg fornemmer at pris også kunne være en faktor?). Til forskel fra traditionelle operativsystemer til computere, er Chrome OS dog møntet specifikt på at få dig til at bruge Googles webbaserede tjenester (mere om softwaren bag på, så hverken software eller hardware er beregnet til at lagre data på selve enheden, og der er sjældent meget diskplads tilgængelig til f.eks. billeder.

Et hurtigt kig på markedet identificerer Acer Chromebook 15 ( og Lenovo S330 ( som populære Chromebook i 2k kr.-klassen, men kender ikke maskinerne specifikt.

God jagt :).

Libreboot’ing an X200 using a CH341a based programmer
Jun 4th, 2019 by miki

Here’s a preliminary HOWTO from my recent external flashing of the BIOS ROM on a Lenovo X200 thinkpad (Wikipedia). The particular firmware flashed was a Libreboot build for this machine (instructions for X200 and details of the external flashing procedure) but anything goes (but anything may not be useful, though).

I’ll amend this HOWTO with more detailed instructions and pictures in the following days (warning: a prediction) to hopefully make it more complete and useful for the vary inhabitants of LibreBootLand.

Some parts

A programmer kit was bought on AliExpress for $4.20 containing a USB programmer board and an SOIC-8 clip which ended up not being used as the particular X200 had a SOIC-16 chip so a separately ordered SOIC-16 chip ($3.11)  was used.

“MinProgramment” aka. CH341a Programmer

Buy: @ $4.20

The programmer is based on the WCH CH341a chip which is an USB <-> seriel/parallel/uart interface. The manufacturer WCH being  WinChipHead aka. WCH (Nanjing QinHeng Electronics Co.,Ltd) (maybe also aka. WCH-IC (Jiangsu Qinheng Co., Ltd)). There are lots of options for buying board varieties based on the CH341a chip, to get you started here is a BangGood search and an AliExpress search.

Boards like this has also been described by others including a deduced schematic, EEVblog critique of the I/O pin power on similar boards (not yet confirmed whether that is true for this programmer too, I guess so, but at least one flashing done without damage) and a mention on hackaday of other board types.

There are a bunch of downloads from the WCH site regarding the chip including  a Chinese datasheet, no English language documentation seems to be available from the manufacturer however. There are some English editions of the datasheet to be found, of unknown origin. They seem plausible enough to use, though. Somebody has attempted to collect documentation about the chip in a Git repository.

The SOIC-16 Clip (aka. Pomona 5252)

Buy: @ $3.11

To attach physically to the Macronix MX25L6405D flash memory chip in a SOIC-16 package present on the X200 in question (words are that this is the norm although the board can be populated with a SOIC-8 too) a clip that matches the pins of the SOIC-16 package is needed. I bought the one mentioned above for $3.11 at random from AliExpress and this worked fine. In the pictures the wiring is hooked up correctly to the programmer to allow for flashing as described below.


WARNING: Below is still a draft made from mental notes! Ask me if you need more information or check back soon (I promise).


6405 <-> CH341a

MISO<->MIOS (label error, should be MISO)



CS <-> SS


First tried driving the the flash chip from VDD on ch341a but this was unsuccessful, no chip could be found, so the 6405 was hooked up to external 3.3v power supply with supply GND connected to GND on CH341a to align the ground potential between ch341a I/O supply and 6405 supply (important!).


Machine being flashed

Update Embedded Controller

To get the latest ECP (Embedded Controller Program) from Lenovo (no free alternative exists) containing software for the MCU controlling low level hardware like battery charging/keyboard/backlight stuff you need to update the BIOS which also updates the ECP. Most recent version for X200 is “BIOS: 3.22 / ECP: 1.07“. This is not needed if you already have these versions on the machine, check current versions by pressing ThinkVantage during boot and choosing “Enter Setup”.

If your system has a Windows installation download and run the “BIOS Update Utility“executeable. Else you’ll need to get the “BIOS Update Bootable CD” and somehow get it on a CD and find a CD-ROM drive. Alternatively on a Linux system the CD file system can be extracted and added to Grub to be directly bootable. Below was done on an Ubuntu 16.04 system:

$ sudo apt install genisoimage syslinux
$ wget -q
$ geteltorito 6duj48us.iso > 6duj48us.img
Booting catalog starts at sector: 20
Manufacturer of CD: NERO BURNING ROM
Image architecture: x86
Boot media type is: harddisk
El Torito image starts at sector 27 and has 75776 sector(s) of 512 Bytes
Image has been written to stdout ….
$ sudo cp /boot
$ sudo cp /usr/lib/syslinux/memdisk /boot
$ sudo nano /etc/grub.d/40_custom
<add lines below to the end of file, preserve the “exec tail…” line>
menuentry “BIOS Update” {
linux16 /memdisk
initrd16 /
$ sudo update-grub

Reboot, press <left shift> key while booting to access Grub, choose BIOS Update menu entry and follow the Lenovo update procedure. To start flashing it requires both a connected power supply and also a working, non-exhausted battery (!) mounted in the machine. This is tiresome for owners of worn out batteries…

Some notes about the flashing process can be found in the documentation of a patch set for the Lenovo BIOS.

Machine doing the programming

Install Flashrom

sudo apt install flashrom

ch341a support in flashrom



Download the stable LibreBoot firmware:

The brave will of course want to compile it themselves.

$ cd
$ wget
--2019-06-07 07:35:21--
Resolving (, 2001:630:341:12::184
Connecting to (||:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1632800 (1,6M) [application/x-xz]
Saving to: ‘libreboot_r20160907_grub_x200_8mb.tar.xz’

libreboot_r20160907_grub_x200_8mb.tar.xz 100%[================================================================================>]   1,56M  --.-KB/s    in 0,1s    

2019-06-07 07:35:21 (13,9 MB/s) - ‘libreboot_r20160907_grub_x200_8mb.tar.xz’ saved [1632800/1632800]
$ tar tf libreboot_r20160907_grub_x200_8mb.tar.xz 

Customise MAC address

As the MAC address of the ethnernet PHY is stored in the flash, yo have your X200 ethernet MAC address correspond to the sticker on the back of the machine, and also avoid a potential but improbable DHCP/ARP conflict, the MAC address from the label/ifconfig from the existing system must be embedded into the flash file that we are going to program into the flash chip.

For this a tool called ich9gen is needed, this is a part of the libreboot repository and we need to build it ourselves.

Build ich9gen

$ git clone
Cloning into 'libreboot'...
remote: Counting objects: 29080, done.
remote: Compressing objects: 100% (9855/9855), done.
remote: Total 29080 (delta 18748), reused 27899 (delta 18057)
Receiving objects: 100% (29080/29080), 63.90 MiB | 11.13 MiB/s, done.
Resolving deltas: 100% (18748/18748), done.
Checking connectivity... done.
$ cd libreboot/projects/ich9gen/sources
$ make
gcc -I. -Wall -Wextra -g -std=c99 -c src/ich9deblob.c -o obj/ich9deblob.o
gcc -I. -Wall -Wextra -g -std=c99 -c src/common/descriptor_gbe.c -o obj/common/descriptor_gbe.o
gcc -I. -Wall -Wextra -g -std=c99 -c src/descriptor/descriptor.c -o obj/descriptor/descriptor.o
gcc -I. -Wall -Wextra -g -std=c99 -c src/gbe/gbe.c -o obj/gbe/gbe.o
gcc -I. -Wall -Wextra -g -std=c99 -c src/common/x86compatibility.c -o obj/common/x86compatibility.o
gcc -I. -Wall -Wextra -g -std=c99 obj/ich9deblob.o obj/common/descriptor_gbe.o \
	obj/common/x86compatibility.o obj/descriptor/descriptor.o obj/gbe/gbe.o \
	 -o ich9deblob
gcc -I. -Wall -Wextra -g -std=c99 -c src/ich9gen.c -o obj/ich9gen.o
gcc -I. -Wall -Wextra -g -std=c99 -c src/ich9gen/mkdescriptor.c -o obj/ich9gen/mkdescriptor.o
gcc -I. -Wall -Wextra -g -std=c99 -c src/ich9gen/mkgbe.c -o obj/ich9gen/mkgbe.o
gcc -I. -Wall -Wextra -g -std=c99 obj/ich9gen.o obj/ich9gen/mkdescriptor.o obj/ich9gen/mkgbe.o \
 obj/common/descriptor_gbe.o \
	obj/common/x86compatibility.o obj/descriptor/descriptor.o obj/gbe/gbe.o \
	 -o ich9gen
gcc -I. -Wall -Wextra -g -std=c99 -c src/demefactory.c -o obj/demefactory.o
gcc -I. -Wall -Wextra -g -std=c99 obj/demefactory.o obj/common/descriptor_gbe.o \
	obj/common/x86compatibility.o obj/descriptor/descriptor.o obj/gbe/gbe.o \
	 -o demefactory

Run ich9gen

Running ich9gen itself generates the flash descriptor (fd) header including possible configuration section where the MAC address is stored for the gigabit ethernet (gbe) PHY onboard the ICH9 chipset. When run six 12 KiB files for respectively 4, 8 and 16 MiB binary images and chipsets including (gbe) and excluding (nogbe) gigabit ethernet PHY are generated.

“aa:bb:cc:dd:ee:ff” in the commandline should be replaced with the actual 12 hex digits from the label on the machine or by running ifconfig on the machine using the existing Lenovo BIOS.

$ cd ~/libreboot_r20160907_grub_x200_8mb/
$ ~/libreboot/projects/ich9gen/sources/ich9gen --macaddress aa:bb:cc:dd:ee:ff
You selected to change the MAC address in the Gbe section. This has been done.

The modified gbe region has also been dumped as src files: mkgbe.c, mkgbe.h
To use these in ich9gen, place them in src/ich9gen/ and re-build ich9gen.

descriptor and gbe successfully written to the file: ich9fdgbe_4m.bin
Now do: dd if=ich9fdgbe_4m.bin of=libreboot.rom bs=1 count=12k conv=notrunc
(in other words, add the modified descriptor+gbe to your ROM image)

descriptor and gbe successfully written to the file: ich9fdgbe_8m.bin
Now do: dd if=ich9fdgbe_8m.bin of=libreboot.rom bs=1 count=12k conv=notrunc
(in other words, add the modified descriptor+gbe to your ROM image)

descriptor and gbe successfully written to the file: ich9fdgbe_16m.bin
Now do: dd if=ich9fdgbe_16m.bin of=libreboot.rom bs=1 count=12k conv=notrunc
(in other words, add the modified descriptor+gbe to your ROM image)

descriptor successfully written to the file: ich9fdnogbe_4m.bin
Now do: dd if=ich9fdnogbe_4m.bin of=yourrom.rom bs=1 count=4k conv=notrunc
(in other words, add the modified descriptor to your ROM image)

descriptor successfully written to the file: ich9fdnogbe_8m.bin
Now do: dd if=ich9fdnogbe_8m.bin of=yourrom.rom bs=1 count=4k conv=notrunc
(in other words, add the modified descriptor to your ROM image)

descriptor successfully written to the file: ich9fdnogbe_16m.bin
Now do: dd if=ich9fdnogbe_16m.bin of=yourrom.rom bs=1 count=4k conv=notrunc
(in other words, add the modified descriptor to your ROM image)

Apply Flash Descriptor to Binary

$ cd ~/libreboot_r20160907_grub_x200_8mb/
$ cp -v x200_8mb_usqwerty_vesafb{,_customised}.rom
'x200_8mb_usqwerty_vesafb.rom' -> 'x200_8mb_usqwerty_vesafb_customised.rom'
$ dd if=ich9fdgbe_8m.bin of=x200_8mb_usqwerty_vesafb_customised.rom bs=1 count=12k conv=notrunc
12288+0 records in
12288+0 records out
12288 bytes (12 kB, 12 KiB) copied, 0,0299453 s, 410 kB/s


Programmer Setup Validation / Lenovo BIOS backup

flashrom -p ch341a_spi -c MX25L6405D -r rom1.bin

flashrom -p ch341a_spi -c MX25L6405D -r rom2.bin

flashrom -p ch341a_spi -c MX25L6405D -r rom3.bin

flashrom -p ch341a_spi -c MX25L6405D -r rom4.bin

flashrom -p ch341a_spi -c MX25L6405D -r rom5.bin

cmp rom{1,2}.bin

cmp rom{1,3}.bin

cmp rom{1,4}.bin

cmp rom{1,5}.bin


$ sudo flashrom -p ch341a_spi -c MX25L6405D -w ~/libreboot_r20160907_grub_x200_8mb/x200_8mb_usqwerty_vesafb_customised.rom

Accounts of LibreBoot Flashing

Embedded Controller (EC) information

[Danish] Stallman til Danmark i Maj 2019!
Apr 7th, 2019 by miki

Update: Jeg mødte Richard i Odense, fik lov at sponsorere FSF og fik en GNU med hjem!

Mikkel & RMS (og GNU)
SDU, Odense

Rygterne har lydt noget tid, men nu er det officielt at formand for og stifter af Free Software Foundation, den ideologiske ophavsmand til GNU-projektet og højlydt fortaler for softwarebrugeres frihed og privatliv i den digitale verden, Richard Stallman besøger Danmark med en række åbne og gratis foredrag dette forår.

Det er Stallmans dedikerede arbejde med fri software og GNU-projektet fra starten af 1980’erne, herunder udformning af softwarelicenser som GNU GPL og udviklingsværktøjer som GNU Compiler Collection (GCC) og GNU Emacs, der er grundlaget for en stor del af det der i offentligheden i dag bedst kendes som “open source”. I Stallmans og GNUs terminologi benævnes det dog retteligt “fri software” (på engelsk: “free software”) for at fremhæve at etablering og bevarelse af softwarens, og slutbrugeren af dens, frihed er det egentlige rationale for at give kildekoden fri.

Kernen Linux er frigivet under GNU GPL og er både inspireret af og anvender GNU-projektets arbejde direkte, og er en vigtig del af et komplet GNU-system (også kendt som GNU/Linux eller en “Linux-distribution”).

Stallman kommer på en veritabel Danmarksturne med start i Aalborg mandag d. 6. maj 2019 og ender i København fredag d. 10.  maj 2019. Foredragsrækken er arrangeret af innovationsnetværket for IT, InfiniIT, som inkluderer de store IT-universiteter i Danmark.

Den samlede foredragsrække er som følger:

Tidspunkt Lokation Begivenhed hos FSF Begivenhed hos InfinIT Anden omtale
Mandag d. 6. maj 2019


Aalborg Universitet
Auditoriet, Lokale 1.12
Niels Jernes Vej 8A
9220 Aalborg SØVejviser:

Richard Stallman – “Free software and your freedom” Free Software, Free Society – Richard Stallman og den frie software-bevægelse (AAU)
Tirsdag d. 7. maj 2019


Syddansk Universitet
Lokale U170
Bygning 44
Campusvej 55
5230 OdenseVejviser:

Richard Stallman – “The dangers of mass surveillance” A Free Digital Society – Richard Stallman og den frie software-bevægelse
Onsdag d. 8. maj 2019


IT-Universitetet i København
Rued Langgaards Vej 7
2300 København SVejviser:

Richard Stallman – “Free software and your freedom in computing” A Free Digital Society – Richard Stallman og den frie software-bevægelse
Torsdag d. 9. maj 2019


Københavns Universitet
Københavns Biocenter
Lundbeckfond Auditorium Ole Maaløes Vej 5
2200 København NVejviser

Richard Stallman – “Computing, freedom, and privacy” Free Software, Free Society – Richard Stallman og den frie software-bevægelse (KU)
Fredag d. 10. maj 2019


Danmarks Tekniske Universitet
Auditorium 116/81 (bygning 116)
Ved Bygningstorvet på Knuth-Wintherfeldts Allé
2800 Kongens LyngbyVejviser:

Richard Stallman – “Copyright vs Community”

(ændrede lokationsoplysninger ikke opdaterede her)

Copyright vs Community Richard Stallman og den frie software-bevægelse

Kilder: FSF: Where in the world is Richard Stallman?, InfinIT-arrangementer, IDA-søgning, PROSA-arrangementer

Begivenhederne er også tilføjet den åbne kalender GriCal:

Information om Richard/GNU/FSF

De primære kilder er hovedsageligt på engelsk:

Kilder på dansk


Anden omtale

Micro:bit – Official Android mobile application maturity and future
Jan 31st, 2019 by miki

The support request replicated below was posted as ticket #20427 on Micro:bit support on 2019-01-31 22:19 CET spawned by discussion in F-Droid RFP #662 about inclusion of the official Micro:bit Android Companion application in the free software application store F-Droid.

Hi at Micro:bit Educational Foundation.

We are wondering a bit in the F-Droid free software community ( whether it is worthwhile for us to try to loosen the official Android companion application ( from its non-free dependencies to make it available in the free software application store F-Droid (

This leads to a couple of questions you can hopefully help answering;

1) Do you regard the application as alive and supported?

The latest release of the application was v2.0 2017-01-17 ( and the publicly available code base ( seems to have been completely abandoned. Only two commits were ever made by Samsung and no involvement with the community has been seen at all.

2) How come the big difference in maturity between the iOS and Android mobile applications?

It seems like the iOS application has received some more attention seeing regular updates through to v3.0.2 released 2018-11-01 ( Also it appears to have a much wider fetaureset ( developed along the way by Insight Resources (

The Android application appears to have been more of a one-off project from Samsung having all sorts of issues especially with Bluetooth that has never been attended to (,

3) Is there a plan to bring the application in better shape?

Some activity can be seen in repository forks and branches from the original Samsung committer ailrohit (…ailrohit:school_project) and microbit-sam (…microbit-sam:partial-flash) identifying as being from the foundation but none of this work seem to be included in releases yet.

4) If a freed fork is made for inclusion in F-Droid would you be willing and able to integrate the changes into the official sources?

F-Droid prefers an upstream source which can be directly built without non-free dependencies using an appropriate set of build options. This greatly simplifies maintenance and build efforts. A forked repository is already in place at the foundation’s Github organization ( but is at the moment even with the stale Samsung repository.

Thanks for any clarifications you can provide.


Stallman in 2012: Denmark supposedly a free country, still valid
Mar 3rd, 2017 by miki

Stumbled upon this slightly dated talk by Richard M. Stallman (aka. RMS) of GNU and FSF fame, in which my home country of Denmark is sadly referenced as only a “supposedly free country”.


“But censorship is wrong, of course, whether it is done on the internet or not. We used to think that the internet would protect us from censorship because it was too hard to censor the internet. But thanks to the efforts of various companies in the US, The UK, France and so on, it is now possible for governments to censor the internet and also surveil it completely, they just need to put enough effort in. And this is not limited to obvious tyrannies such as China and Iran. We see a lot of supposedly free countries imposing censorship on the internet.

For instance, Denmark several years ago imposed filtering on the internet blocking a secret list of sites. The list was leaked and posted on WikiLeaks. Hooray for WikiLeaks! Whereupon Denmark blocked access to that page too. So everyone else could know what internet users in Denmark were blocked from seeing except those people.”

Sadly since this time it has not gotten any better. Most of the points RMS makes (the whole talk is worth a listen) are still valid and a grave concern from my perspective. The Danish internet (really DNS) blocking system has been broadened and the slippage that was feared has become a reality. Even though this issue has gotten some attention in the IT and rights communities the general public just doesn’t care.

The actual block is technically done through DNS blacklists that Danish ISP are legally required to implement. The list of blocked sites is available from the telecom trade organization “Telekommunikationsindustrien i Danmark” (English: Telecommunication’s Industry Association in Denmark) at and currently has 111 sites (csv) on active block.

As it being DNS based if you are impacted, workarounds do exist. However, my guess is that they will soon be able to actively shut down services physically located in Denmark.

Full talk

Below are links to the full talk, and an inline/embedded player courtesey of youtube. Start time of all links are at starting point of above transcript.


Generating passwords for Mosquitto MQTT broker using PHP
Jan 13th, 2017 by miki

EDIT 2021-07-11: prompted by an email from a reader the approach described below was refined into a script which can be used as a (sort of) drop-in replacement for mosquitto_passwd, find it on sourcehut in my hometools repository as mosquitto_passwd.php (first edition also on Even though it generates a pre-2.0 plain hash using SHA512 this is still parsable by 2.0 and later. However, 2.0 adds support for PBKDF2 aka. RFC2898 on top of SHA512 with 20.000 iterations which is also the default generated by 2.0+ mosquitto_passwd, but the broker is still able to parse previous SHA512 hashes (notice the algorithm identifier after <username>:$, 6 for SHA512, 7 for PBKDF2-SHA512, similar to common /etc/shadow convention and extensions to implementations of POSIX crypt()).

Here is a delayed write-up of my involvement in a question posted to the liberally licensed MQTT broker (server) Mosquitto’s developer list list about how to generate authentication tokens programmatically. It kicked the curious cat in me which propelled a journey into the backyards of the C code for the mosquitto_passwd tool which normally is used for this purpose. This resulted in the proof of concept PHP implementation outlined in my answer on the list which is reproduced below.

MQTT (once Message Queue Telemetry Transport) is a lightweight publish/subscribe protocol intended for communication between low power, low bandwidth embedded devices. These days it is commonly hyped as a holy grail in the religion of IoT. The protocol was originally developed by IBM but is now a standard overseen by the OASIS standardization organization which also has the OpenDocument standard (ODF, think Open/Libre-Office) under its wings. According to Wikipedia MQTT is used behind the scenes of Facebook Messenger, OpenStack and Amazon’s IoT services.

For further practical use of the concept outlined you would need to produce a random 16 byte base64 encoded salt to feed into the hasher, that could be done using something like; $salt_base64=base64_encode(openssl_random_pseudo_bytes(12));

If your need a shrink wrapped solution to this you could try to ping me.

Hi Srinivas.

On 2016-07-26 12:49, Srinivas Pokala wrote:
> Username successfully created using linux command with: 
> "mosquitto_passwd /etc/mosquitto/passwd guest".
> I need to create same with php or javascript how?

Looking at the source of mosquitto_passwd
basically all it does to generate the resulting line you see in the
password file is:

1) draw a random 12 byte binary salt
2) hash the combination of password and salt using sha512
3) write username, base64 encoded salt, base64 encoded hash in one line

A PHP implementation would use something like this ($salt is fixed for
demonstration purposes, it ought to be random in production);

$hash=hash("sha512",$password.$salt, true);

Comparing against mosquitto_passwd using a one-liner (uses the base64
salt from output to be able to correlate the two);

$ mosquitto_passwd -b ~/mosq_passwd_test Bitten Insect
$ cat ~/mosq_passwd_test

$ php -r '$username="Bitten"; $password="Insect";
$salt_base64="mfJ0Eq3rIDLKG33r"; $salt=base64_decode($salt_base64);
$hash=hash("sha512",$password.$salt, true);

As can be seen, the PHP generated password line are identical to the
mosquitto_passwd generated.

I have also successfully tested authentication against the mosquitto
broker with PHP generated users. One caveat is that the above can
generate a salt of arbitrary length, but the broker must see a 12 byte
binary salt (16 byte base64) or authentication will fail.

Note however, that this hasn't been tested on more than a few
username/password pairs, there might be other issues lurking.

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