A new blog post about developing OpenWRT in QEMU with Eclipse Che

_posts/2024-05-22-developing-openwrt-in-qemu.adoc

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+---
+title: Developing OpenWRT in QEMU with Eclipse Che
+layout: post
+author: Oleksii Orel
+description: >-
+  Developing OpenWRT helloworld package in QEMU machine emulator and virtualizer with Eclipse Che.
+categories: []
+keywords: ['openwrt', 'quemu', 'gdb', 'developing ', 'workspace']
+slug: /@olexii.orel/openwrt-helloworld-package
+---
+
+https://openwrt.org/[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 https://openwrt.org/docs/guide-developer/creating-a-cmake-package-in-openwrt[OpenWRT CMake packages] with Eclipse Che.
+
+In this blog post, we will review developing OpenWRT in https://www.qemu.org/[QEMU] with Eclipse Che in 4 parts:
+
+<<part1>>
+
+<<part2>>
+
+<<part3>>
+
+<<part4>>
+
+
+NOTE: In this blog post, we will use the next devfile:
+[source,yaml]
+----
+schemaVersion: 2.2.2
+metadata:
+  generateName: openwrt-helloworld
+attributes:
+  controller.devfile.io/storage-type: ephemeral
+projects:
+  - name: openwrt-helloworld
+    git:
+      remotes:
+        origin: https://github.com/che-incubator/openwrt-helloworld-package.git
+  - name: openwrt
+    zip:
+      location: https://github.com/openwrt/openwrt/archive/refs/tags/v21.02.3.zip
+components:
+  - name: runtime
+    container:
+      image: quay.io/che-incubator/openwrt-builder:latest
+      memoryLimit: 6656Mi
+      memoryRequest: 512Mi
+      cpuLimit: 10000m
+      cpuRequest: 1000m
+      mountSources: true
+      endpoints:
+        - exposure: public
+          name: file-server
+          protocol: https
+          targetPort: 8080
+          path: /bin/targets
+  - name: qemu
+    container:
+      image: quay.io/che-incubator/openwrt-runner:latest
+      memoryLimit: 1536Mi
+      memoryRequest: 256Mi
+      cpuLimit: 1500m
+      cpuRequest: 500m
+      mountSources: true
+      endpoints:
+        - exposure: public
+          name: luci
+          protocol: https
+          targetPort: 30080
+        - exposure: internal
+          name: ssh
+          protocol: tcp
+          targetPort: 30022
+commands:
+  - id: installpackagedefinitions
+    exec:
+      label: Install all package definitions
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt
+      commandLine: scripts/feeds update -a -f && scripts/feeds install -a -f
+      group:
+        kind: build
+  - id: linkhelloworldpackage
+    exec:
+      label: Link helloworld package
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}
+      commandLine: ln -sr openwrt-helloworld/package/helloworld openwrt/package/
+      group:
+        kind: build
+  - id: unlinkhelloworldpackage
+    exec:
+      label: Unlink helloworld package
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}
+      commandLine: unlink /projects/openwrt/package/helloworld
+      group:
+        kind: build
+  - id: copyconfig
+    exec:
+      label: Copy diff-config to OpenWRT
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}
+      commandLine: cp -f openwrt-helloworld/configs/.x86-generic.config openwrt/.config && cd openwrt && make defconfig
+      group:
+        kind: build
+  - id: savedifconfig
+    exec:
+      label: Save diff-config to openwrt-helloworld
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt
+      commandLine: scripts/diffconfig.sh > /projects/openwrt-helloworld/configs/.x86-generic.config
+      group:
+        kind: build
+  - id: buildhelloworldpackage
+    exec:
+      label: Build helloworld package
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt
+      commandLine: make package/helloworld/compile V=s CONFIG_DEBUG=y
+      group:
+        kind: build
+  - id: prebuiltresources
+    exec:
+      label: Add prebuilt resources
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt-helloworld
+      commandLine: scripts/add-prebuilt-resources.sh
+      group:
+        kind: build
+  - id: buildallpackages
+    exec:
+      label: Build all packages and the kernel
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt-helloworld
+      commandLine: scripts/build.sh
+      group:
+        kind: build
+  - id: qemustart
+    exec:
+      label: Running OpenWRT in a QEMU VM
+      component: qemu
+      workingDir: ${PROJECTS_ROOT}
+      commandLine: /usr/local/bin/prepare-and-run-vm.sh
+  - id: gdbsshstart
+    exec:
+      label: Start remote GDB Server
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt-helloworld
+      commandLine: scripts/start-gdb-server.sh
+  - id: gdbsshaccess
+    exec:
+      label: Remote access to OpenWRT via SSH
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt-helloworld
+      commandLine: scripts/start-ssh.sh
+      group:
+        kind: build
+  - id: serverstart
+    exec:
+      label: Start Http-Server
+      component: runtime
+      workingDir: ${PROJECTS_ROOT}/openwrt
+      commandLine: npx http-server -a 0.0.0.0 -p 8080 -o bin/targets
+      group:
+        kind: build
+----
+
+## PART 1: Quick start with prebuild recourses [[part1]]
+
+Prebuilt resources could be applied for a quick start with Eclipse Che. We could do it 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.
+
+image::/assets/img/developing-openwrt/add-prebuilt-resources.png[Add prebuilt resources]
+{nbsp} +
+
+## PART 2: (optinal)Build all packages and the kernel [[part2]]
+
+After creating a new workspace from https://github.com/che-incubator/openwrt-helloworld-package.git[openwrt-helloworld-package], we need to copy https://github.com/che-incubator/openwrt-helloworld-package/blob/main/configs/.x86-generic.config[`.config`] file, install all package definitions and build all packages and the kernel. We can do it by running the following tasks from the devfile:
+
+1. `Copy diff-config to OpenWRT`
+2. `Install all package definitions`
+3. `Build all packages and the kernel`
+
+NOTE: The build process may take a while. After the build is complete, we can see the `openwrt-*.img.gz` file in the `output` directory.
+
+image::/assets/img/developing-openwrt/build-all-packages-and-the-kernel.png[Build all packages and the kernel, 100%]
+{nbsp} +
+
+## PART 3: Run OpenWRT in QEMU [[part3]]
+
+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.
+
+image::/assets/img/developing-openwrt/running-openwrt-in-qemu-vm.png[Running OpenWRT in a QEMU VM]
+{nbsp} +
+
+We can access the OpenWRT console by running the task `Remote access to OpenWRT via SSH` and start the helloworld package by running:
+
+[source, bash]
+----
+helloworld
+----
+
+image::/assets/img/developing-openwrt/run-helloworld.png[Run helloworld package]
+{nbsp} +
+
+## PART 4: Debugging helloworld package [[part4]]
+
+After starting OpenWRT in a QEMU VM, we need to run a remote gdbserver for debugging. We can do it by running the task `Start remote GDB Server` from the devfile.
+
+image::/assets/img/developing-openwrt/start-remote-gdbserver.png[Start remote gdbserver]
+{nbsp} +
+
+Then, we can debug the helloworld package with IDE:
+
+image::/assets/img/developing-openwrt/remote-debugging.png[Start remote gdbserver]
+{nbsp} +
+
+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.