Portable started as the safe, efficient WeChat sandbox at 10th November, 2024. We have released over 132 tags and the first birthday of Portable is creeping close. I felt the urge to write a brief summary of what’s included in the upcoming X release, and the future road map of this project.

What’s inside X

Much faster performance

We have exploited the bash’s concurrency feature to an extent. Most features like detecting your graphics configuration, starting the D-Bus proxy and setting up the protected environment has been offloaded from the main process. Together with the new readiness notifier system, this allows a 30%+ increase of pure startup performance. On a system with many cores, for example a Core i9 14900HX the new release will yield much more performance increase, up to 30% faster observed on my machine. Some efforts (but not all) are listed below:

- Dropped the DOCUMENTS dir query
- Rewritten the command line parser
- Delegated the folder setup process to a background process
- Optimised readiness notifier
- The helper now delegates readiness notify to a background process
- Optimised the random number generation process to use bash's built-in `$RANDOM` variable which returns a value <32767

Rewritten cmdline parser

The old command line parser was great, but it was not perfect. We have rewritten it to make it faster, safer and more reliable.

Pools and Portable no longer executes in a sandbox

This feature was added to prevent scripts from creating another sandbox which will obviously fail in a portable sandbox. Since the service manager isn’t reachable, the D-Bus proxy always fail and block the entire process.

Read-only, private cgroup FS mounted in sandbox

To prepare for the possible, upcoming standard of identifying sandboxed processes via attributes on cgroup, we have instructed systemd to mount a private copy of cgroup fs and explicitly tell bubblewrap to mount /sys/fs/cgroup to read-only, of which prevents sandboxed applications from doing weird stuff to the host and escape in some extent.

GStreamer VA now works in Portable.

This is primarily done for sandboxing Epiphany (or GNOME Web). GStreamer VA requires the respective renderer node under /sys/class/drm in addition to /dev/dri. We have rewritten some portion of the code to always make that happen. Note that GStreamer VAAPI still does not work and we do not have a plan of fixing since it’s replaced by VA.

Homed users no longer see a crash on some apps

systemd-homed has a socket io.systemd.Home under /run/systemd/userdb/io.systemd.Home. Some applications (WeChat) will query user information and the absence of such socket on a homed system causes a crash on startup. We now expose them read-only to prevent such issue.

Exposed the global font cache

Generally I see no reason not to do it.

That is a glimpse of what Portable X enhances. The ninth release to celebrate the birthday of Portable project.

What’s next?

Some ideas are listed for future implementations:

Better multi-GPU support:

We are planning to co-operate with the potentially new, upcoming gpu-daemon (presentation file here) to enhance our GPU selection and binding logic, make it more configurable, robust and easy for users, with better desktop integration.

For document editors: detect when file paths are passed, and automatically pass them into the sandbox.
Further performance optimisations.
Zypak-like wrapper for Chromium applications, or allow nested namespaces.
Implement process identifying through CGroups, when specs are ready. (Source here)