Developing OpenWRT in QEMU with Eclipse Che

OpenWrt is a highly extensible GNU/Linux distribution for embedded devices (typically wireless routers). OpenWrt is built from the ground up to be a full-featured, easily modifiable operating system for embedded devices. You can have all the features you need with no bloat, powered by a modern Linux kernel.

We can create and develop OpenWRT CMake packages with Eclipse Che.

In this blog post, we will review developing OpenWRT in QEMU with Eclipse Che in 4 parts:

PART 1: Quick start with prebuild resources

PART 2: (optional) Build all packages and the kernel

PART 3: Run OpenWRT in QEMU

PART 4: Debugging helloworld package

Note	In this blog post, we will use OpenWrt HelloWorld package.

First of all, we need to create a new workspace from the repo openwrt-helloworld-package with Eclipse Che. The easiest way to do this is to use Eclipse Che hosted by Red Hat and create a workspace by navigating to the following URL - https://workspaces.openshift.com#https://github.com/che-incubator/openwrt-helloworld-package.

PART 1: Quick start with prebuild resources

Prebuilt resources could be applied for a quick start with Eclipse Che. We could do this by running the next tasks from the devfile:

1. Add prebuilt resources

Note	After adding prebuilt resources, we should see the openwrt-*.img.gz file in the output directory. Prebuilt resources were added to the runtime image during the last successful GitHub image build action.

 

PART 2: (optional) Build all packages and the kernel

Instead of using prebuilt resources from STEP 1, we can install all package definitions, copy .config file and build all packages and the kernel. We can do this by running the following tasks from the devfile:

1. Install all package definitions

2. Copy diff-config to OpenWRT

3. Build all packages and the kernel

Note	The build process may take a while, which is why using prebuilt resources from STEP 1 could be more desirable for getting started quickly. After the build is complete, we can see the openwrt-*.img.gz file in the output directory.

 

PART 3: Run OpenWRT in QEMU

After adding prebuilt resources or building all packages and the kernel, OpenWRT could be run in the QEMU VM by running the following tasks from the devfile:

1. Running OpenWRT in a QEMU VM

After running the task, we see the OpenWRT booting in the QEMU machine emulator and virtualizer.

 

We can access the OpenWRT console by running the task Remote access to OpenWRT via SSH and start the helloworld package by running:

helloworld

 

PART 4: Debugging helloworld package

After starting OpenWRT in a QEMU VM, we need to run a remote gdbserver for debugging. We can do this by running the task Start remote GDB Server from the devfile.

 

Then, we can debug the helloworld package with IDE:

 

Note	The task Start remote GDB Server should be run before each new debug session.

Thank you for reading. I hope you found this article helpful.