We have seen in the previous session how difficult can be to port a simple application to Unikraft. This is an effort that does not scale well, as we don't want to go through the effort of porting every time we want to use a new application. Even more, if we want to use a closed-source application, we might not be able to port it since we can not make changes to the source code.
In order to fix this, we ported an elfloader application, that can load a binary application along with it's libraries and run it.
This makes it a lot easier to port applications, since all we have to do is create a filesystem with the application binary and it's required libraries, on our usual Linux setup.
We need to pass the filesystem to the Unikraft application at runtime.
We will do that by creating a cpio archive.
Also, we will give the program name that we want to run as an argument to elfloader, using -append.
helloworld in Bincompat Mode#Follow the instructions from the README file of elfloader and run a simple application.
The application code that will be compiled and run will be placed in rootfs/.
helloworld Applications#Make some changes in the code from rootfs/.
Make the application more complex, change it however you want.
You can add more source files, but make sure to add them to the Makefile.
Aplications that need networking will need some extra libraries.
Follow the instructions in the README file.
For this, we will use the elfloader-net application.
As in the prevoius sessions, the IP address of the application will be 172.44.0.2.
Choose an application from your system.
You can use something similar to what we used in the last session, ls, id, echo, cat, etc.
Everything that does not have to do with processes should work.
Try as many applications as possible.
If networking is needed, use the elfloader-net application as a starting base.
Feel free to ask questions, report issues, and meet new people.