C# development in a FreeBSD jail?
05 Oct 2024While VSCode and DotNet generally works on FreeBSD, the “C# Dev Kit” does not due to the following issue: FreeBSD build of C# Dev Kit
Knowing that FreeBSD jails support running an almost full features linux system and also X11 apps, I was curious whether it would be possible to run VSCode including “C# Dev Kit” in a jail.
Here is what I learned.
Setting up the Jail
For the basic linux jail setup I mostly followed this great article:
Setting up a (Debian) Linux jail on FreeBSD
After several attempts, this is the jail configuration I finally used for my experiments
devuan {
host.hostname = "${name}.jail";
interface = re0;
ip4.addr= 192.168.0.113;
allow.raw_sockets=1;
allow.sysvipc;
path = "/opt/jails/${name}";
exec.start = "/etc/init.d/rc 3";
exec.poststart = "jexec ${name} mkdir /tmp/.X11-unix; jexec ${name} chmod 777 /tmp/.X11-unix; mount_nullfs /tmp/.X11-unix /opt/jails/${name}/tmp/.X11-unix";
exec.stop = "/etc/init.d/rc 0";
exec.poststop = "umount -f /opt/jails/${name}/tmp/.X11-unix; umount -f -a -F /opt/jails/${name}.fstab";
persist;
allow.mount;
allow.mount.procfs;
allow.mount.linsysfs;
allow.mount.tmpfs;
allow.mount.devfs;
allow.mlock;
mount.fstab = "/opt/jails/${name}.fstab";
}
To simplify the network setup, I decided for direct network access. I also learned that “devfs” needs to be mounted via fstab to also support “/dev/shm”.
I used “exec.poststart” and “exec.poststop” to automatically setup unix socket for X11 and also to unmount the fstab entries as this didn’t happen automatically when shutting down the jail.
It also took me several attempts to finally come up with this fstab.
# Dev Mountpoint FS Options Dump/Check
devfs /opt/jails/devuan/dev devfs rw,late 0 0
tmpfs /opt/jails/devuan/dev/shm tmpfs rw,late,mode=1777 0 0
fdescfs /opt/jails/devuan/dev/fd fdescfs rw,late,linrdlnk 0 0
linprocfs /opt/jails/devuan/proc linprocfs rw,late 0 0
linsysfs /opt/jails/devuan/sys linsysfs rw,late 0 0
tmpfs /opt/jails/devuan/tmp tmpfs rw,late,mode=1777 0 0
Setting up X11
For setting up X11 I mostly followed this article: Jailing GUI Applications
I set up a non root user as follows:
adduser dev1
usermod -aG video,audio,input,plugdev dev1
Additionally to the Unix socket setup (see jail.conf) I ran xhost + on the host to allow X11 access.
I also had to copy the “.Xauthority” from my home directory at the host system and then added the following lines to “/home/dev1/.profile”
export DISPLAY=:0.0
export XAUTHORITY=/home/dev1/.Xauthority
To run X11 apps it is important to enter the jail without root permission:
jexec devuan su - dev1
I tried the X11 setup by running “mousepad” which, apart from some warnings, worked pretty well!
(mousepad:3416): dconf-WARNING **: 10:43:01.335: failed to commit changes to dconf: Could not connect: Connection refused
Setting up VSCode
I downloaded the “deb” package from the VSCode home page and used apt install to install it.
The first attempt failed. I had to adjust the apt cache by adding the following line to “/etc/apt/apt.conf”:
APT::Cache-Start "104857600";
After running apt-get update, I succeeded installing VSCode.
The first attempt to run VSCode failed:
dev1@devuan:~$ code --verbose
/usr/share/code/code: error while loading shared libraries: libffmpeg.so: cannot open shared object file: No such file or directory
[3476:0922/104437.119547:FATAL:zygote_host_impl_linux.cc(198)] Check failed: . : Invalid argument (22)
To fix these issues I installed ffmpeg and added the following configuration for the dynamic linker:
echo "/usr/share/code" > /etc/ld.so.conf.d/vscode.conf
During my research I found hints to try running VSCode using “–no-sandbox” option.
Second attempt
But also the second attempt failed:
dev1@devuan:/usr/share/code$ code --no-sandbox --verbose
[4701:0922/105600.213686:ERROR:file_path_watcher_inotify.cc(890)] Failed to read /proc/sys/fs/inotify/max_user_watches
[4700:0922/105600.213687:ERROR:file_path_watcher_inotify.cc(890)] Failed to read /proc/sys/fs/inotify/max_user_watches
[4699:0922/105600.214927:ERROR:bus.cc(407)] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
[4699:0922/105600.452318:ERROR:bus.cc(407)] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
[4699:0922/105600.452390:ERROR:bus.cc(407)] Failed to connect to the bus: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory
[4699:0922/105600.453678:ERROR:bus.cc(407)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[4699:0922/105600.453740:ERROR:bus.cc(407)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[4699:0922/105600.453766:ERROR:bus.cc(407)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[4699:0922/105600.453988:ERROR:file_path_watcher_inotify.cc(337)] inotify_init() failed: Function not implemented (38)
[4699:0922/105600.454940:ERROR:bus.cc(407)] Failed to connect to the bus: Could not parse server address: Unknown address type (examples of valid types are "tcp" and on UNIX "unix")
[4699:0922/105600.455001:ERROR:platform_shared_memory_region_posix.cc(214)] Creating shared memory in /dev/shm/.org.chromium.Chromium.x7kIrq failed: No such file or directory (2)
[4699:0922/105600.455029:ERROR:platform_shared_memory_region_posix.cc(217)] Unable to access(W_OK|X_OK) /dev/shm: No such file or directory (2)
[4699:0922/105600.455043:FATAL:platform_shared_memory_region_posix.cc(219)] This is frequently caused by incorrect permissions on /dev/shm. Try 'sudo chmod 1777 /dev/shm' to fix.
At this point I updated the fstab to support “/dev/shm”.
To make “DBus” running I removed the following check from “/etc/init.d/dbus”:
if ! mountpoint -q /proc/ ; then
log_failure_msg "Can't start $DESC - /proc is not mounted"
return
fi
Third attempt
Finally, I was able to launch VSCode with the following command:
code --no-sandbox --disable-file-watcher --verbose
It worked, but the terminal was still flooded with warnings and errors.
Installing DotNet SDK
I followed Microsoft’s guide to install the .NET SDK: https://learn.microsoft.com/en-us/dotnet/core/install/linux-debian
But apt-get update caused the following error
W: Failed to fetch https://packages.microsoft.com/debian/12/prod/dists/bookworm/InRelease Bad header line Bad header data [IP: 13.107.246.45 443]
To fix this problem I ran:
curl -fsSL https://packages.microsoft.com/keys/microsoft.asc | gpg --dearmor -o /usr/share/keyrings/microsoft-prod.gpg
rm -rf /var/lib/apt/lists/*
apt-get update
Then the installation succeeded:
apt-get install -y dotnet-sdk-8.0
Installing “C# Dev Kit” VSCode extension
The installation of “C# Dev Kit” extension finished without any visible error from the extension manager but the in the logs i found:
The .NET Core SDK cannot be located: Error running dotnet --info: Error: Command failed: dotnet --info
Failed to create CoreCLR, HRESULT: 0x8007FF02
I continued my research and found the following issue: https://github.com/dotnet/runtime/issues/44417
After having added “allow.mlock” to the jail configuration I could successfully run
dotnet new
but when I tried
dotnet new console
I got the following error:
The template "Console App" was created successfully.
Processing post-creation actions...
Restoring /home/dev1/ws/test/test.csproj:
MSBUILD : error : This is an unhandled exception in MSBuild -- PLEASE UPVOTE AN EXISTING ISSUE OR FILE A NEW ONE AT https://aka.ms/msbuild/unhandled
MSBUILD : error : System.Threading.ThreadStateException: Unable to set thread priority.
MSBUILD : error : at System.Threading.Thread.SetPriorityNative(Int32 priority)
MSBUILD : error : at System.Threading.Thread.set_Priority(ThreadPriority value)
MSBUILD : error : at Microsoft.Build.BackEnd.RequestBuilder.SetCommonWorkerThreadParameters()
MSBUILD : error : at Microsoft.Build.BackEnd.RequestBuilder.RequestThreadProc(Boolean setThreadParameters)
Restore failed.
Post action failed.
Manual instructions: Run 'dotnet restore'
Despite extensive research, I couldn’t find a workaround for this issue. At this point I stopped the experiment.
Conclusion
It seems FreeBSD jails are not suitable for C# development. I hope Microsoft fixes the issue in the “C# Dev Kit” soon. In the mean time I will start a new experiment: Arch Linux in bhyve