How do you sandbox /proc by the way? So that the app doesn't crash due to missing /proc/self/exe link or /proc/ID/stat file, but cannot read my private information (like /proc/cmdline, /proc/mounts etc)? Things like bind mounts do not work on /proc.

I ended up with writing a FUSE-based emulation in Python, but there are lot of issues with permissions and namespaces:

- I could run my /proc emulator in the same PID namespace as the target, but in a different mount namespace so that I can mount real /proc there. This is not safe because the target could send signals or ptrace my emulator and gain access to the real /proc. Especially if it is an AI agent, they are pretty capable.

- I could run the emulator in a different mount and PID namespaces but then the emulator needs to translate PIDs into the target namespace, and for this I need to know the format of all files and where they contain PIDs and it is a pain

- running the poorly coded emulator as a root is not an option. The sandbox must work without root.

- ideally the emulator should run as a different user because Linux provides the strongest isolation for processes of different users, but in this case I won't be able to access target's /proc entries.

Also, running a program is the most basic functionality of an OS and you suggest that I need to write my own sandbox to do this because it is not included with Linux. Maybe that is why this year still is not the year of Linux on desktop.