This document aims to explain how to develop on devices running the reference Apertis images.

Which image to choose

The APT-based fixedfunction and hmi images are the ones providing all the flexibility needed for development, letting developers install and remove packages, and otherwise customize the rootfs.

The OSTree-based images are tailored as a reference for product deployments: their constraints make installing and removing packages impossible, and the more care must be taken to get write access to the rootfs managed by OSTree.

Making a device suitable for development

Apertis device images come with some restriction out-of-the-box when trying to develop directly on them:

  • only the target APT repository is enabled by default, while most of the useful development tools are in the `development` repository
  • the rootfs is mounted read-only
  • some utilities are kept to a older, less featureful versions since the newer ones switched to GPLv3
  • target images deliberately don’t have development/debugging tools installed

To easily overcome these issues, Apertis images ship the apertis-dev tool. To get a basic set of development tools (somewhere between the official target and development images) you can log in on the serial console or use the xterm, and run:

$ sudo apertis-dev --help
usage: sudo apertis-dev [OPTIONS]
Enable debugging and basic development.
    -b|--build: install basic build tools
    -d|--build-dep PACKAGE: install build-deps of PACKAGE
    -g|--debug: install basic debugging tools
    -3|--gpl3: install GPL3 versions of tar, coreutils
    --enable-debug: enable debug logging from applications
    --disable-debug: disable debug logging from applications
For developer use only: do not do this in production.

For instance, to install gdbserver, run:

$ sudo apertis-dev
$ sudo apt install gdbserver

Please note that a machine where this has been done is not a “pure” target image; if a bug was reported for target images, please confirm the fix on a target image without these development tools.

Using SSH

Accessing the device via SSH is generally more convenient than using a serial console or xterm. To do so, add the following to your ~/.ssh/config file:

Match host apertis*
    User user
    IdentityFile ~/.ssh/apertis.ssh
    IdentitiesOnly yes
    StrictHostKeyChecking no
    UserKnownHostsFile /dev/null

Generate a new key which you will use for connecting to all Apertis target images:

$ ssh-keygen -t rsa -N "" -f ~/.ssh/apertis.ssh

Then, for each new target image installation you have, set up the key, replacing $hostname with the board’s hostname:

$ ssh-copy-id -i ~/.ssh/ user@$hostname

You should then be able to SSH in using:

$ ssh $hostname

Building software

The recommended environment to build platform packages and application bundles is the Apertis SDK.

However, it is also possible to build software on the devices directly with the preparation steps below:

$ sudo apertis-dev --build --gpl3
$ sudo apt install apertis-dev-tools