Assembly language on OpenBSD, using bhyve for FreeBSD development, FreeBSD Gaming, FreeBSD for Thanksgiving, no space left on Dragonfly’s hammer2, and more.

##Headlines

This is a short introduction to assembly language programming on OpenBSD/amd64+arm64. Because of security features in the kernel, I have had to rethink a series of tutorials covering Aarch64 assembly language on OpenBSD, and therefore this will serve as a placeholder-cum-reminder.

OpenBSD, like many UNIX and unix-like operating systems, now uses the Executable and Linkable Format (ELF) for its binary libraries and executables. Although the structure of this format is beyond the scope of this short introduction, it is necessary for me to explain part of one of the headers.

Within the program header there are sections known as PT_NOTE that OpenBSD and other systems use to distinguish their ELF executables - OpenBSD looks for this section to check if it should attempt to execute the program or not.

It’s often a good idea to prototype your assembly programs in a high level language such as C - it can then double up as both a set of notes and a working program that you can debug and compile into assembly language to compare with your own asm code.

###Using bhyve for FreeBSD Development

The bhyve hypervisor requires a 64-bit x86 processor with hardware support for virtualization. This requirement allows for a simple, clean hypervisor implementation, but it does require a fairly recent

See the article for the very technical breakdown of the following:

Network Setup

Bridged Configuration

Private Network with NAT

Using dnsmasq with a Private Network

Running Guests via vmrun.sh

Configuring Guests

Using a bhyve Guest as a Target

Conclusion

The bhyve hypervisor is a nice addition to a FreeBSD developer’s toolbox. Guests can be used both to develop new features and to test merges to stable branches. The hypervisor has a wide variety of uses beyond developing FreeBSD as well.

##News Roundup

What do all programmers like to do after work? Ok, what do most programers like to do after work? The answer is simple: play a good game! Recently at the Polish BSD User Group meetup mulander was telling us how you can play games on OpenBSD. Today let’s discuss how this looks in the FreeBSD world using the “server only” operating system.

One of the ways of playing natively is to play indie games which use XNA. XNA is a framework from Microsoft which uses .NET, for creating games. Fortunately, in the BSD world we have Mono, an open source implementation of Microsoft’s .NET Framework which you can use to run games. There is also FNA framework which is a reimplementation of XNA which allows you to run the games under Linux. Thomas Frohwein, from OpenBSD, prepared a script, fnaify. Fnaify translate all dependencies used by an FNA game to OpenBSD dependencies.

I didn’t test it with many games, but I don’t see any reason why it shouldn’t work with all the games tested by the OpenBSD guys. For example, with:

Cryptark

Rouge Legacy

Apotheon

Escape Goat

Bastion

CrossCode

Atom Zombie Smasher

Open-Source games

In FreeBSD and OpenBSD we also will find popular games which were open sourced. For example, I spend a lot of time playing in Quake 3 Arena on my FreeBSD machine. You can very simply install it using pkg: # pkg install ioquake3

Then move the files for the skins and maps to the .ioquake3 directory from your copy of Quake. In the past I also played UrbanTerror which is a fully open source shooter based on the Quake 3 Arena engine. It’s is also very easy to install it from ports: # pkg install iourbanterror

In the ports tree in the games directory you can find over 1000 directories, many of them with fully implemented games. I didn’t test many games in this category, but you can find some interesting titles like:

All those titles are simply installed through the packages. In that case I don’t think FreeBSD has any difference from OpenBSD.

One of the big advantages of FreeBSD over OpenBSD is that FreeBSD supports wine. Wine allows you to run Windows applications under other operating systems (including mac). If you are a FreeBSD 11 user, you can simply fetch wine from packages: # pkg install i386-wine

To run Windows games, you need to have a 32-bit wine because most of the games on Windows are built on 32-bits (maybe this has changed – I don’t play so much these days). In my case, because I run FreeBSD-CURRENT I needed to build wine from ports. It wasn’t nice, but it also wasn’t unpleasant. The whole step-by-step building process of a wine from ports can be found here.

As you can see there are many titles available for *BSDs. Thanks to the FNA and fnaify, OpenBSD and FreeBSD can work with indie games which use the XNA framework. There are many interesting games implemented using this framework. Open source is not only for big server machines, and there are many re-implementations of popular games like Theme Hospital or RollerCoaster Tycoon 2. The biggest market is still enabled through wine, although its creates a lot of problems to run the games. Also, if you are an OpenBSD user only this option is not available for you. Please also note that we didn’t discuss any other emulators besides wine. In OpenBSD and FreeBSD there are many of them for GameBoy, SNES, NeoGeo and other games consoles.

###FreeBSD For Thanksgiving

I’ve been working on FreeBSD for Intel for almost 6 months now. In the world of programmers, I am considered an old dog, and these 6 months have been all about learning new tricks. Luckily, I’ve found myself in a remarkably inclusive and receptive community whose patience seems plentiful. As I get ready to take some time off for the holidays, and move into that retrospective time of year, I thought I’d beat the rush a bit and update on the progress

vandamme 13.0-CURRENT FreeBSD 13.0-CURRENT #45 881fee072ff(hwp)-dirty: Mon Nov 19 16:19:32 PST 2018 bwidawsk@vandamme:/usr/home/bwidawsk/usr/obj/usr/home/bwidawsk/usr/src/amd64.amd64/sys/DEVMACHINE amd64

6 months later, I feel a lot less uncertain about making the right decision. In fact, I think both opportunities would be great, and I’m thankful this Thanksgiving that this is my life and career. I have more plans and things I want to get done. I’m looking forward to being thankful again next year.

###hammer2: no space left on device on Dragonfly BSD

hammer2 does not actually delete a file when you rm or unlink it. Since recovery of the file is possible (this is the design of hammer2), there will still be an entry taking up data. It’s similar to how git works.

If you have a recent enough version of the rescue ramdisk installed, on bootup you can press ‘r’ and access the rescue ramdisk. Your provider will have to offer some sort of remote interface for interacting with the operating system before it boots, like VNC or IPMI. You can then mount your filesystem using:

[root@ ~]# mkdir /tmp/fs

If you receive an error that /sbin/hammer2 is not found, then your rescue ramdisk is not up to date enough. In that scenario, download the latest 5.2 iso from dragonflybsd.org and boot from the cd-rom on your virtual machine or physical device. Just login as root instead of installer.

[root@ ~]# /sbin/hammer2 bulkfree /tmp/fs

If you do not have enough memory on your machine, you may need to mount swap. Add your swap partition to the /etc/fstab and then do:

[root@ ~]# swapon -a

Once you have ran the bulkfree command twice, the usage reported by df -h will be correct. However, there is a chance on reboot that a core dump will be placed in /var/crash/ so be prepared to have plenty of space free in case that happens. You should also delete any files you can and run the bulkfree operation twice afterwards to clear up additional space.

##Beastie Bits

##Feedback/Questions