Libbpf userspace function bpf_program__insns
Gives read-only access to BPF program's underlying BPF instructions.
Definition
const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog);
Parameters
prog: BPF program for which to return instructions
Return
A pointer to an array of BPF instructions that belong to the specified BPF program
Usage
Returned pointer is always valid and not NULL. Number of struct bpf_insn pointed to can be fetched using bpf_program__insn_cnt API.
Keep in mind, libbpf can modify and append/delete BPF program's instructions as it processes BPF object file and prepares everything for uploading into the kernel. So depending on the point in BPF object lifetime, bpf_program__insns can return different sets of instructions. As an example, during BPF object load phase BPF program instructions will be CO-RE-relocated, BPF subprograms instructions will be appended, ldimm64 instructions will have file descriptors embedded, etc. So instructions returned before bpf_object__load and after it might be quite different.
Example
Docs could be improved
This part of the docs is incomplete, contributions are very welcome