High level ELF write API

[konstin]

We're currently using two libraries for patching ELF files (PyO3/maturin#2932): Goblin for "linting" build artifacts and reading the RPATH, where it has convenient high-level functions, and object for adjusting RPATH/SONAME/etc. through arwen. I've been looking at the faerie example for writing ELF files, but it seems there's no typed, safe ELF write API, with which we could replace parsing with both goblin and object with using goblin specifically for ELF files.

[m4b]

Yea sounds interesting! Do you imagine the high level writer api lives in goblin? Generally I would prefer more niche things to be a separate crate and provide all the apis you’d need to write it, eg adding the pwrite support to all/most of the elf and macho structures, etc so faerie could be written.

Anyway let me know what you’re thinking !

[konstin]

I'm impartial to where it lives, if there's an api to modify and write goblin::elf::Elf in another crate, I'm happy :) I'd assume the more difficult part is keeping the offset and invariants in an goblin::elf::Elf instance intact when e.g. adding a DT_NEEDED entry.

[philipc]

Have a look at https://github.com/wolfv/goblin-ext. It's new, and I've only glanced at it, but it appears to cover much of what you want.