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Developers’ Weblog

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I’ve been debugging a weird problem at work – after upgrading a complex system from lenny to wheezy, some https clients failed to connect: GNU wget and Debian’s version of lynx(1) which is linked against libgnutls26 fail. NSS applications continue to work, as does cURL; wget and lynx on MirBSD (linked with OpenSSL of course) work. Even Debian’s gnutls-cli tools from both gnutls26 and gnutls28 work. Huh. The error_log shows renegotiation problems, yet setting the new Apache 2 configuration option to “use insecure renegotiation” doesn’t help either. (The option is a total #FAIL: its only other value is “use secure TLSv1.x renegotiation”, but I don’t want/need SSL renegortiation at all, anyway.) Natureshadow told me this was a hot issue on Debianforum at the moment, yet, nobody had a clue or enough information to file a formal bugreport against (initially) apache2, as that’s what changed. I tracked it down on a new VM with no configuration otherwise, and here are my findings so others don’t run into it.

Tracking down the problem, this can be reduced to the following configuration (minimised, to show the problem) in /etc/apache2/sites-enabled/1one:

	<VirtualHost *:443>
		RedirectMatch permanent .
		SSLEngine on
		SSLCertificateFile /etc/ssl/W_lan_tarent_de.cer
		SSLCertificateKeyFile /etc/ssl/private/W_lan_tarent_de.key
		SSLCertificateChainFile /etc/ssl/

Do not mind the actual content, this is a very stripped-down demo on a not-actually-set-up-yet box.

Same is valid for the companion configuration file /etc/apache2/sites-enabled/2two:

	NameVirtualHost *:443

	<VirtualHost *:443>
		SSLEngine on
		# workaround for BEAST (CVE-2011-3389), short-term
		SSLCipherSuite RC4-SHA
		SSLCertificateFile /etc/ssl/W_lan_tarent_de.cer
		SSLCertificateKeyFile /etc/ssl/private/W_lan_tarent_de.key
		SSLCertificateChainFile /etc/ssl/
		SSLProtocol TLSv1

Turns out the BEAST workaround was at fault here: the differing SSLCipherSuites between the vhosts (on the same Legacy IP / TCP Port tuple, as we use Wildcard SSL Certificates) made Apache 2 want to renegotiate, so either commenting it on 2two or, better, adding it to 1one helped. Interestingly enough, the SSLProtocol directive did not matter (in my tests).

So, keep SSL settings synchronised between vhosts. In fact, those were already from include files, but 2two was from the “Evolvis 5” generation, whereas we added to 1one an Include of the file generated by the previous releases of EvolvisForge and had not switched those legacy vhosts to the new configuration, as everything worked on lenny.

This wlog entry brought to you by the system administrators of tarent solutions GmbH and the Evolvis Project, based on FusionForge.

Update 17.05.2013 – Absolutely do not use RC4-SHA for SSL/TLS (https)! It can leak over 200 initial plaintext bytes easily. (arc4random(3) is not affected from this, especially on MirBSD, nor arc4random(9).)

Originally posted by bubulle on Planet Debian, a shell prompt that displays the current git branch, in colour on some terminals, after the current working directory. The following snippet does similar things for mksh users, except it doesn’t redefine your prompt but amend it – just throw it at the bottom of your ~/.mkshrc before that last line beginning with a colon (copy from /etc/skel/.mkshrc if you haven’t done that yet):

	function parse_git_branch {
		git branch 2>/dev/null | sed -n '/^\* \(.*\)/s//(\1)/p'

	function amend_prompt_with_git {
		local p q='$(parse_git_branch)' r

		if [[ $TERM = @(xterm-color|xterm|screen*) ]]; then
			if [[ ${PS1:1:1} = $'\r' ]]; then

		p=${PS1%%*( )[#$]*( )}
		if [[ $p != "$PS1" ]]; then
			# prompt ends with space + #-or-$ + space, we can amend
			r=${PS1: ${#p}}
	unset -f amend_prompt_with_git

The indirection by use of a function is not strictly necessary but allows the use of locals. I took the liberty of adding an asterisk after “screen” to match the GNU/Linux nonsense of having TERM=screen.xterm or somesuch.

KiBi is my hero of the day. I’ve long wondered why I couldn’t select fixed-misc as font on my workstation at the dayjob, which is running K?buntu Hardon Heroin. (Luckily, I managed to avoid upgrading to Prolonged Pain.) Now I guess that’ll work again.

My work laptop (running testing) also has got this thingy. My keyboard layout now has got a grml branch (named after the person who first cursed about the insane idea of those toy-breaking boys to rearrange the keycodes) that works with it. Since Debian is marginally more sane than K?buntu, in contrast to the gnu branch I use on my orkstation, the grml branch still has Meta on the left Alt key, not Mode_switch, as it still works in uxterm, which reduces the diff between the MAIN branch (HEAD) on XFree86® and this beast.

And finally: defaults to a black screen and disabled mouse pointer until an application first requests it. Totally unacceptable for evilwm(1) users, and letting people think it crashed, to boot. The Arch Linux guys found this, among others; the fix is: startx(1) users edit /etc/X11/xinit/xserverrc to add -retro behind the X, or copy the file to ~/.xserverrc and change it there:


	exec /usr/bin/X -retro -nolisten tcp "$@"

For display managers, similar files exist in /etc/kde4/kdm and related places.

Update: Also, newer xterm(1) justify an update to ~/.Xresources for we can finally get rid of cut buffers, and get a blinking underline cursor to boot!

On the other front, worked on Debian packaging, and upstream on pax(1) and jupp, with more things to follow (especially in mksh). Also fixed about ⅔ Linux klibc architectures and learned why I’m a BSD developer despite all the bad parts of it ☺ and fixed fakeroot with pax(1) on Hurd… incidentally in code originally designed to support the Linux pax. My dayjob’s keeping me busy, but I’ve got plans to run mksh(1) through Sonar, in addition to the static code analysēs done by (once again, thanks!) Coverity (commits to mksh pending) and Clang/LLVM scan-build. Uhm, what can I say more, grab me in IRC if you need it. Ah, and some other mksh things coming up that may be of interest to people needing to support legacy scripts.

While wtf(1) always has been a bit central to MirBSD, and the acronym database has been accessible by CVSweb, what we never had was a DAU compatible (and shellsnippets compatible) lookup. This has now changed: the above link to the acronyms file is a persistent link to its latest version (well, latest when the website was last recompiled), tooltips may very well follow soon, and we’ve got an online WTF lookup service.
Contributions to the acronym database are welcome, of course; just eMail them to

Not to stop there, our online HTML manpage search is also new, shiny, and should replace the “!mbsdman” DuckDuckGo hash-bang shortly. (Both of these services offer a DDG search as fallback. Note that DDG is an external service included herein by linking, under their request to spread it, and not affiliated with The MirOS Project. They do, however, donate some advertising money to Debian.)
For all those who didn’t know: only manpages for software in the MirOS BSD base system and for the MirPorts Framework package tools are listed, not for third-party applications installable using ports or, recently, pkgsrc®. Still, if you want to have a peek at a modern classic BSD’s documentation, you’re welcome. (Not to mention content like re_format(7) and style(9) and that some of our documentation is much more legible than others.)

And because writing all that perl(1) made me ill, not to mention I don’t even know that language, I’ve hacked a bit more in the mirmake(1) and mksh(1) parts of the MirWebsite, finally implementing pointing out where in the navigation sidebar the visitor currently is.

We also have exciting mksh porting news involving RT trying a larger number of ancient platforms than I dare count, me fixing bugs in Linux klibc and diving into other things, learning more about why I consider me lucky for hacking a BSD operating system… sorry, I want to keep this short as it’s mostly an announcement.

The MirWebsite source code is, of course, also available. Improvements welcome. Except for these three CGIs, our website is fully statically precompiled, and that’s a good thing. Please help in making the CGIs secure.

blog @ TNF

20.03.2012 by bsiegert@

So now I am even posting over at TNF on Julian Fagir made new NetBSD flyers, and I committed them to the TNF website.

I know that I should write more here but there is not much new on the MirBSD front.

I updated the showcase to NetBSD-6_BETA on the Dom0, and now X refuses to start. Oh well. X does start when using a GENERIC kernel. This is very bad for showcase use, of course :(. pkgsrc is going into freeze very soon, and I did not do a whole lot of MirBSD fixes this time around. This is due to illness, searching for a new job, and working on the Go programming language, which is expected to hit version 1.0 Real Soon Now(TM).

I brushed up my Algorithms and Data Structures a bit by reading the third volume of TAOCP. Fantastic book.

This weekend, the FOSDEM 2012 took place in Brussels. We gave away DVDs with the latest MirOS BSD snapshot and about 3 GiB of binary packages for pkgsrc.

I gave a talk entitled “pkgsrc on MirBSD”. It gives a short introduction to both MirBSD and pkgsrc and details how we managed to get MirBSD supported as a platform, including some details on the new-developer process at the NetBSD foundation. The slides are now available on slideshare or as a PDF for download. —

The showcase is doing strange things. The NetBSD-current kernel panics reproducibly when the network card, an alc, does not have a link. Thus, I put it on a switch with no other connection to “fix” the problem. Furthermore, I have a half-finished pkg_rolling-replace on the NetBSD side; various things now give Memory Errors, including running xfce4-session. Oh well. WindowMaker to the rescue … I am planning on redoing the setup on this machine anyway, once NetBSD-6-alpha will have been branched. I would also like to use LVM to set up the partitions for the Xen domains, to avoid going through a vnd(4) device.

Courtesy of Rob Pike on Google+ and Richard Kettlewell in the comments:

In Plan 9 and Research Unix, rm(1) also removes empty directories. Why doesn't it in Unix? In V7 Unix, only privileged users could unlink() a directory. Thus, rmdir(1) was a setuid executable. rm(1) actually called rmdir(1) via fork()+exec() in its recursive mode. Of course, there were some bugs in rmdir ...

On MirBSD and other sane OSes, you can just press ^T (Ctrl-T) when dd(1) runs; this sends it a SIGINFO (cf. sigaction(2)) which asks it to display (progress) information to the tty. This includes kFreeBSD, btw.

Update 07.01.2012 – this also works on Hurd. Linux neither has SIGINFO nor (cooked mode tty) support for it.

There’s also pv:

	dd if=/dev/mapper/vg01-${customername}--hudson bs=1048576 | \
	    pv -pter -B 1048576 -s 85899345920 | \
	    xz -0 >/mnt/ci-${customername}-snap-20120105-lenny.img.xz

I used this At wOrk today to back up a Jenkins VM before upgrading its underlying operating system for evaluation. Here, the -s flag is the total size (in bytes; don’t forget to multiply by 1024 when reading from Linux’ /proc/partitions) so pv can calculate a total and an ETA; -B is the same as bs; and xz is the currently best compressor to use, in any situation, unless you must stay compatible to gzip(1)-only systems. (Except that it’s not under an Open Source licence.)

clpbar might also be worth looking into. XTaran points out sid has this as bar.

PSA: Last of June, 2012, will be a leap second.

Quick! A webserver!

04.01.2012 by bsiegert@
Tags: golang tip

If, like me, you occasionally want to transfer some files via http—like the sets for a MirOS installation—but are much too lazy to set up apache, here is a simple web server in nine lines of Go:

	package main

	import (
		. "net/http"

	func main() {
		Handle("/", FileServer(Dir(".")))
		log.Fatal(ListenAndServe(":8080", nil))

It simply exports the current directory via http on port 8080. Neat!

What’s going on in MirOS Project land? Other than all developers being buried in dayjob work, of course… (sorry for that, guys; even tg@ has now succumbed to an ever-growing backlog but will be back, some time)

tg@ uploaded a new MirBSD-current/i386 snapshot (20111228) plus a full set of HTML manpages for all architectures (so they all are in the new amber style), and redid the usual combined i386+sparc cdrom10.iso Midi-ISO as well as the kit. Older binary packages may no longer be supported: the old libgcc_s DLL is no longer provided in fixes10.ngz, and it may be time to reduce the amount of packages in MirPorts to concentrate on those worth the effort and receiving enough care.

Thanks to bsiegert@’s amazing work, the pkgsrc® kit of anno 2007 could finally be deleted. The page about pkgsrc® on MirOS describes instructions to use instead. At some point, we may release a binary bootstrap kit along with the snapshots as set ready for pickup by the installer.

No MirGRML based on the latest Grml 2011.12 release will be made. We’ll be investigating a possible solution for a flavour of the popular GNU/Linux OS to accompany full Triforce Live CDs in the future (for now, we’ll keep the old MirGRML 2009.10 on them).

We hope to be able to return to investing more spare (heh…) time into development some time. For now, we apologise for the slowed down development and reaction even in important subprojects such as mksh. Occasionally, they do have updates, e.g. the latest Jupp/Win32 release, or fixes in CVS.

This is a very late announcement. Binary packages for pkgsrc-2011Q3 are now available on The repository contains 5330 packages built on MirOS-current. Any MirOS BSD version from 2011 should work.

The packages are self-contained in /usr/pkg: The VARBASE has been set to /usr/pkg/var, and the package database is in /usr/pkg/db. This matches the MirPorts defaults and facilitates using pkgsrc and MirPorts side by side.

In this quarterly release, the new default for MirBSD is to use “modular” X11, i.e. install Xorg libraries and programs as packages instead of using the system X libs. This improves the compatibility with many newer programs, which expect for example that the X libraries have pkg-config files. This should not change anything for the user, however.

For more information on how to use these packages, consult the pkgsrc page on or the relevant section of the pkgsrc guide.

This is both a release announcement for the next installment of The MirBSD Korn Shell, mksh R40b, and a follow-up to Sune’s article about small tools of various degrees of usefulness.

I hope I don’t need to say too much about the first part; mksh(1) is packaged in a gazillion of operating environments (dear Planet readers, that of course includes Debian, which occasionally gets a development snapshot; I’ll wait uploading R40c until that two month fixed gcc bug will finally find its way into the packages for armel and armhf). Ah, we’re getting Arch Linux (after years) to include mksh now. (Probably because they couldn’t stand the teasing that Arch Hurd included it one day after having been told about its existence, wondering why it built without needing patches on Hurd…) MSYS is a supposedly supported target now, people are working on WinAPI and DJGPP in their spare time, and Cygwin and Debian packagers have deprecated pdksh in favour of mksh (thanks!). So, everything looking well on that front.

I’ve started a collection of shell snippets some time ago, where most of “those small things” of mine ends up. Even stuff I write at work – we’re an Open Source company and can generally publish under (currently) AGPLv3 or (if extending existing code) that code’s licence. I chose git as SCM in that FusionForge instance so that people would hopefully use it and contribute to it without fear, as it’s hosted on my current money source’s servers. (Can just clone it.) Feel free to register and ask for membership, to extend it (only if your shell-fu is up to the task, KNOPPIX-style scripts would be a bad style(9) example as the primary goal of the project is to give good examples to people who learn shell coding by looking at other peoples’ code).

Maybe you like my editor, too? At OpenRheinRuhr, the Atari people sure liked it as it uses WordStar® like key combinations, standardised across a lot of platforms and vendors (DR DOS Editor, Turbo Pascal, Borland C++ for Windows, …)

ObPromise: a posting to raise the level of ferrophility on the Planet aggregators this wlog reaches (got pix)

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