Spill the beans

In my previous article, I showed a way to setup and jump into a root file system in order to test a software in this environment.

Using PRoot, such task looks really easy and does not require any privileges. We will now finish this setup in order to build and test VLC media player in this new root file system.

Setting up the RootFS

In the previous article we had downloaded and configured a Debian root file system ready to be used with PRoot.

In order to build and test VLC media player in this environment, we must install VLC dependencies. For instance in a Debian system, I already explain the procedure in an article about the compilation for Linux users.

The first step is to install theses dependencies using apt-get:

#!/bin/sh
% proot -b /etc/resolv.conf -b /dev -b /proc \
        -b /sys -0 debian-6.0-x86_64 /bin/bash
~ echo "deb-src ftp.debian.org/debian squeeze main contrib non-free" >> /etc/apt/sources.list
~ apt-get update
Hit security.debian.org squeeze/updates Release.gpg
Hit ftp.debian.org squeeze Release.gpg
Ign security.debian.org/ squeeze/updates/contrib Translation-en
[...]
Fetched 4655 kB in 2s (1955 kB/s)
Reading package lists... Done
~ apt-get build-dep vlc
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
[...]
[a long list of packages]
[...]
0 upgraded, 410 newly installed, 0 to remove and 0 not upgraded.
Need to get 195 MB of archives.
After this operation, 611 MB of additional disk space will be used.
Do you want to continue [Y/n]?

Pay attention to some packages, like dbus or x11-common, that could not be installed without the right bindings. In fact dbus install script require access to /var/run/dbus/, while x11-common require to not bind /tmp with a working X11 process as it contains files that belong to root and that should be modified during installation.

In order to complete the previous command, you should:

• bind /var/run/dbus
• NOT bind /tmp

apt-get will install a list of packages that were required to compile the version of VLC media player normally installed in the host distribution (vlc version 1.1.3). This mean that some library will be missing. The following packages are also needed:

• git
• autoconf
• libspeexdsp-dev
• libxcb-composite0-dev

Building VLC

You need the code source of VLC media player in this host root file system. I'm personally a bit lazy and I already have the sources somewhere else on my computer so I just bind it in the host root file system:

#!/bin/sh
% proot -b /etc/resolv.conf -b /dev -b /proc \
        -b /sys -b /path/to/vlc/git:/media/vlc.git \
        debian-6.0-x86_64 /bin/bash
~ cd somewhere
~ git clone /media/vlc.git vlc
Cloning into vlc...
done.
~ cd vlc
~ ls
AUTHORS    configure.ac  include      modules	src
autotools  contrib	 INSTALL      NEWS	test
bin	   COPYING	 lib	      po	THANKS
bindings   COPYING.LIB	 m4	      projects
bootstrap  doc		 make-alias   README
compat	   extras	 Makefile.am  share

We should now bootstrap, configure and build VLC media player the usual way:

#!/bin/sh
~ ./bootstrap
generating modules/**/Makefile.am
.....................................................
+ echo
+ cp -f INSTALL INSTALL.git
[...]
+ echo
+ mv -f INSTALL.git INSTALL
+ rm -f 'stamp-h*'
+ set +x
Successfully bootstrapped

Then configure VLC media player in a sub-directory:

#!/bin/sh
~ mkdir build
~ cd build
~ ../configure ..
checking build system type... x86_64-unknown-linux-gnu
checking host system type... x86_64-unknown-linux-gnu
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... yes
checking how to create a ustar tar archive... gnutar
checking whether to enable maintainer-specific portions of Makefiles... yes
checking for style of include used by make... GNU
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
[...]
libvlc configuration
--------------------
version               : 2.1.0-git
system                : linux
architecture          : x86_64 mmx sse sse2
optimizations         : yes
vlc aliases           : cvlc rvlc qvlc svlc nvlc
To build vlc and its plugins, type `make', or `./compile' if you like nice colors.

We disabled mkv and avcodec as libeml and libavcodec versions provided by Debian (in this version of the distribution) are too old.

In order to correctly test VLC, you would want to compile ffmpeg yourself and to give it to the configure script. This is already explained in the article about compilation for Linux users.

Then compiling VLC media player:

#/bin/sh
~ make -j4
[...]

Testing VLC

Running VLC media player under PRoot does not change the way you will test it. In fact most of the tests works the same way in the host root file system or in the guest file system.

You can for example run the VLC automatic tests:

#!/bin/sh
~ make check
[...]

Future work

In the two first article we looked at a way to setup a root file system in order to compile and test a software in this environment.

In the following articles we will extend the possibilities of this method thanks to Qemu. Using Qemu along with PRoot we will be able to test softwares compiled for a different processor like ARM or SH4.