livm — Linux in a Virtual Machine

LiVM is a minimal Linux in a Virtual Machine. It is created to automate testing of low-level utilities like setfont.

It consists of:

1. The Linux Kernel,
2. The GNU C Library,
3. Busybox,
4. The Dropbear SSH Server.

There is nothing more inside, but glibc and scp is a good foundation to bootstrap anything you want. :)

Installation

$ wget https://github.com/dmage/livm/releases/download/v0.2.0/livm-0.2.0.tar.gz
$ tar -xf livm-0.2.0.tar.gz -C /usr/local

Usage

$ livm start ./vm1
$ touch foo && livm scpto ./vm1 ./foo .
$ livm ssh ./vm1 'exec >/dev/tty0; clear; ls -la'
$ livm screenshot ./vm1 screenshot.ppm
$ livm stop ./vm1

Building from the source code

$ if [ "$(uname -s)" == "Darwin" ]; then eval `docker-machine env`; fi
$ make
$ ./bin/livm start ./vm1
$ ./bin/livm ssh ./vm1
$ ./bin/livm stop ./vm1

Error: could not set up host forwarding rule 'tcp:127.0.0.1:2222-:22'

By default, it binds to the host port 2222. If it's already in use by another program or you want to run multiple machines simultaneously, you can choose a different port:

$ LIVM_SSH_PORT=8022 livm start ./vm

Can I run it on macOS?

Yes, all you need is a POSIX shell and QEMU.

Can I build it on macOS?

Yes, but you need Docker.

How to get into a virtual machine if dropbear failed to start?

$ LIVM_DEBUG=1 livm start ./vm

How to enable a framebuffer console?

$ LIVM_VGA=0x303 livm start ./vm

How to get possible values for the VGA parameter?

$ LIVM_DEBUG=1 LIVM_VGA=ask livm start ./vm

How to reconfigure the kernel?

$ make kernel-menuconfig
$ make

How to upgrade the kernel?

Upgrading to X.Y:

$ sed -i.bak -e 's/^\(KERNEL_VERSION =\).*/\1 X.Y/' ./mkinclude/kernel.mk
$ make kernel-menuconfig KERNEL_MENUCONFIG=oldconfig
$ make share/boot/vmlinuz