🏷️ unix  🏷️ openbsd  🏷️ tech 
📆 2020-09-05

OpenBSD on the Desktop (Part I)

Basic Setup with Xorg and dwm

Let’s install OpenBSD on a Lenovo Thinkpad X270. I used this computer for my computer science studies. It has both Arch Linux and Windows 10 installed as dual boot. Now that I’m no longer required to run Windows, I can ditch the dual boot and install an operating system of my choice.

Preparation

First, I grab my work Thinkpad running Arch Linux and some USB dongle big enough for the amd64 miniroot image (roughly five megabytes, that is). This small image does not include the file sets, which will be downloaded during installation instead. I also download the SHA256 checksums from the Swiss mirror, and verify the downloaded image, before I copy it on my dongle:

$ sha256sum -c --ignore-missing SHA256 
miniroot67.fs: OK
$ sudo dd if=miniroot67.fs of=/dev/sda bs=1M

Installation

The Thinkpad X270 is connected to my network through Ethernet. The WiFi firmware usually needs to be installed separately, so only Ethernet will work out of the box. The BIOS has UEFI activated. OpenBSD and UEFI has issues on older hardware (at least on a 2014 Dell laptop I have), but let’s try it on this laptop, anyway.

I plug in the dongle prepared before, and start the computer. I interrupt the regular boot with Enter and pick an alternative boot method by pressing F12. Now I pick my USB dongle. After roughly a minute, the installer has been started. Now I follow these steps:

First Boot

I now restart my laptop, and OpenBSD boots. This takes more time than booting Arch Linux, which uses systemd, whereas OpenBSD uses rc, which performs the startup tasks sequentially.

There’s a message showing up that various firmware (intel-firmware, iwm-firmware, inteldrm-firmware, uvideo-firmware, and vmm-firmware) has been installed automatically. Very nice, indeed.

WiFi Connection

Now that the iwm-firmware has been installed, I can connect right away to my WiFi network frzbxpdb5. I create a file called /etc/hostname.iwm0, wich hostname being a literal string, and iwm0 being the WiFi network card. The connection to my WiFi network consists of a single line:

dhcp nwid frzbxpdb5 wpakey [my-wpakey]

Whereas frzbxpdb5 is my WiFi network’s ESSID, and [my-wpakey] needs to be replaced by the actual WPA key.

Then the networking can be restarted for that device:

# sh /etc/netstart iwm0

This script is kind enough to set the file permissions of /etc/hostname.iwm0 to 640, and then connects to my WiFi network.

I unplug the Ethernet cable and ping openbsd.org, which works fine, even after a restart.

Installing the GUI

My GUI on Unix-like systems is based on the Dynamic Window Manager (dwm) and a couple of other tools, such as dmenu, st, slstatus, slock, all created and maintained by the Suckless community.

This software doesn’t come with configuration facilities, but needs to be configured in the respective C header file config.h, and then re-compiled. Even though OpenBSD offers dwm as a package, customizing and configuring that window manager requires to build it from source.

Building dwm and Friends

First, I need to install git to fetch the source code:

# pkg_add git

Then I fetch the source code for dwm, dmenu, st, and slstatus from Suckless:

$ git clone https://git.suckless.org/dwm
$ git clone https://git.suckless.org/dmenu
$ git clone https://git.suckless.org/st
$ git clone https://git.suckless.org/slstatus

Building dwm

Next, I try to build dwm:

$ cd dwm
$ make

This fails with an error message ('ft2build.h' file not found), which reminds me of building dwm on FreeBSD roughly a month before. Since I can finde the header file at another location:

# find / -type f -name ft2build.h
/usr/X11R6/include/freetype2/ft2build.h

I simply can modify the config.mk accordingly by changing

FREETYPEINC = /usr/include/freetype2

to

FREETYPEINC = $(X11INC}/freetype2

Actually, I only need to comment the above line, and uncomment the line below

# OpenBSD (uncomment)

The Suckless folks obviously are friendly towards OpenBSD, which is also noticable in other places (more evidence to be shown further below).

The next compilation attempt succeeds:

$ make

So let’s install dwm, too:

# make install

By default, and as to be seen in config.h, the keyboard combination [Alt]+[Shift]+[Enter] (deeply engraved into the muscle memories of many dwm users) starts the st terminal. This will be built in a while. However, I prefer to use the Super or Windows key instead of Alt, since the former is of no use in OpenBSD, and the latter still comes in handy when working with the emacs readline mode. Therefore, I change the MODKEY from

#define MODKEY Mod1Mask

to

#define MODKEY Mod4Mask

Then I rebuild and reinstall dwm:

# make install

Building st

Let’s switch over to the st source directory and just try to compile it:

$ cd ../st
$ make

Here, we get a warning that the function pledge (an OpenBSD mitigation, which is built into the master branch, but surrounded by an ifdef preprocessor statement, so that it will only be compiled for OpenBSD) is imported implicitly. Let’s just ignore this warning for now.

What’s worse, the compilation fails with the error message:

ld: error: unable to find library -lrt

Here, the FAQ comes in handy, stating that

If you want to compile st for OpenBSD you have to remove -lrt from
config.mk, ...

Having done so in config.mk, st compiles without any further issues, and, thus, can be rebuilt and installed:

# make install

Building dmenu

Even OpenBSD users with Suckless tools have to open another GUI application than a terminal emulator once in a while. For this purpose, Suckless offers dmenu. Let’s switch over to it and compile it:

$ cd ../dmenu
$ make

Again, we have the issue with ft2build.h, which can be resolved as above with dwm: by using the proper path for FREETYPEINC in config.mk. Afterwards, the build succeeds, and dmenu can be installed:

# make install

Building slstatus

dwm has a status bar on the top right, which can be used to show various information. I used to write some shell commands in .xinitrc to compose such a status line, and then set it by xset -b once every five seconds or so. This approach generates a multitude of processes every couple of seconds.

slstatus is a C programm that is capable of showing various kinds of more or less useful information. Let’s switch over to slstatus and see, what is available in config.def.h:

$ cd ../slstatus
$ less config.def.h

The comments section lists different functions (battery_perc for the battery percentage, datetime for date and time information, temp for thermal information, etc.). I usually display the CPU load, the battery percentage, the memory usage, the current keyboard layout, and the current date and time.

Before configuring those, let’s try to compile slstatus:

$ make

This worked fine, so let’s configure the information to be displayed in config.h:

static const struct arg args[] = {
    /* function    format    argument */
    { datetime,    "%s",     "%F %T" },
};

This renders the current date as follows:

$ date +"%F %T"
2020-09-05 19:26:38

I also like to have the weekday included, but not the seconds, so I define a different argument string:

$ date +"%a %Y-%m-%d %H:%M"
Sat 2020-09-05 19:27

That’s better, so let’s use it in config.h (surrounded with some spaces in the format string):

static const struct arg args[] = {
    /* function    format    argument */
    { datetime,    " %s ",   "%a %Y-%m-%d %H:%M" },
};

The other settings I like to have do not require any arguments, at least not on OpenBSD, so I only need to define a decent format string (with | as a seperator) for those:

static const struct arg args[] = {
    /* function    format           argument */
    { cpu_perc,     " cpu: %s%% |", NULL },
    { battery_perc, " bat: %s%% |", NULL },
    { ram_used,     " mem: %s |",   NULL },
    { keymap,       " %s |"         NULL },
    { datetime,     " %s ",         "%a %Y-%m-%d %H:%M" },
};

This actually compiles, so let’s install it:

# make install

Configuring X Startup

Now that all software is compiled and installed, let’s run X. To do so, a file .xinitrc in the user’s directory is required (/home/patrick/.xinitrc):

setxkbmap ch
slstatus &
exec dwm

This sets the keyboard map for X to Swiss German, starts slstatus in the background, and then executes dwm.

X can now be started by typing startx. This is a bit cumbersome to type every time, so let’s define a symbolic link to it:

# ln -s "$(which startx)" /usr/bin/x

Now let’s start X:

$ x

If everything was configured properly, dwm shows up, and the status line says that the whole system only uses roughly 60 megabytes of RAM. That’s slim. The keyboard combinations to open st and dmenu work, too.

Conclusion

Installing a basic GUI with Suckless software was a rather smooth experience on OpenBSD. (For FreeBSD, I deliberately have chosen a rather fine-grained approach to installing X packages, which caused some additional work.) However, various settings require additional tweaking. I also didn’t use audio yet, which require the volume buttons to be configured accordingly in dwm.

I’ll also need to setup sudo or doas. As a regular Linux user, I’m used to sudo, of course, but the simplicity of doas is a good argument to try it as an alternative.

But those are things I’d like to cover in an upcoming article.