Support for personality(2)?

[woodruffw]

Hi there! Thanks a ton for these bindings, they're a pleasure to use.

Would the nix team be interested in support for the (Linux-specific) personality(2) syscall? It's currently supported in the libc crate but doesn't have higher level bindings to turn the persona argument into a bitflags! enum or to map the return value into a Result.

It's something I'm interested in (and capable of) implementing, if desired.

[asomers]

What's the main use? It seems to me like this should only be done by the ELF loader.

[woodruffw]

I don't think the current dynamic linker/loader on Linux actually calls personality(2), although it may have in the past. Here are a few uses that I can think of:

• Implementing a setarch(8)-style utility in Rust.

• Allowing more fine-grained process spawning. This is my current use case: I want to disable ASLR on a few specific child processes for unit testing purposes.

• Exposing an exec-safe piece of process state -- KRF currently uses personality(2) to signal to the kernel that a particular tree of processes should be instrumented. It's useful to be able to do that outside of the dynamic linker.

[woodruffw]

🎉