Issue with building kern side of code.

[0xMimir]

To build kern side of bpf debugger, this build script is used,

First part of script which is commented out executes this command:

CARGO_TARGET_DIR=target/bpf cargo +nightly-2022-10-10 rustc --package=bpf-recorder --bin=bpf-recorder-kern --features=kern --no-default-features --target=bpfel-unknown-none -Z build-std=core --release -- -Cdebuginfo=2 -Clink-arg=--disable-memory-builtins -Clink-arg=--keep-btf

Second part of script executes this command:

sed -i s/ty__/type/g bpfel-unknown-none/release/bpf-recorder-kern

First part being commented out, means that sed command can be ran on outdated code, or that it doesn't get ran on new code,
This can lead to following error:

libbpf: map 'event_queue': unknown field 'ty__'.
libbpf: failed to initialize skeleton BPF object 'bpf-recorder': -95
thread 'main' panicked at bpf-recorder/src/main.rs:1184:32:
failed to open bpf: -95
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Simple fix is to add following line to build.rs

println!("cargo:rerun-if-changed={}", target_dir);

But better solution would be to fix first step, which currently works when ran outside script but not in it.