Need a way to modify the section name for a read program object

["Eelco Chaudron" <echaudro@xxxxxxxxxx>]

Hi All,

I'm trying to write an xdpdump like utility and have some missing part 
in libbpf to change the fentry/FUNCTION section name before loading the 
trace program.

In short, I have an eBPF program that has a section name like 
"fentry/FUNCTION" where FUNCTION needs to be replaced by the name of the 
XDP program loaded in the interfaces its start function.

The code for loading the ftrace part is something like:

	open_opts.attach_prog_fd = bpf_prog_get_fd_by_id(info.id);
	trace_obj = bpf_object__open_file("xdpdump_bpf.o", &open_opts);

	trace_prog_fentry = bpf_object__find_program_by_title(trace_obj, 
"fentry/FUNCTION");

	/* Here I need to replace the trace_prog_fentry->section_name = 
"fentry/<INTERFACE PROG NAME> */

	bpf_object__load(trace_obj);
	trace_link_fentry = bpf_program__attach_trace(trace_prog_fentry);


See the above, I would like to change the section_name but there is no 
API to do this, and of course, the struct bpf_program is 
implementation-specific.

Any idea how I would work around this, or what extension to libbpf can 
be suggested to support this?

Cheers,

Eelco