int main()

in bpf/xdp_sample_pkts_user.c [111:197]
72 lines of code
17 McCabe index (conditional complexity)

int main(int argc, char **argv)
{
	const char *optstr = "FS";
	int prog_fd, map_fd, opt;
	struct bpf_program *prog;
	struct bpf_object *obj;
	struct bpf_map *map;
	char filename[256];
	int ret, err;

	while ((opt = getopt(argc, argv, optstr)) != -1) {
		switch (opt) {
		case 'F':
			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
			break;
		case 'S':
			xdp_flags |= XDP_FLAGS_SKB_MODE;
			break;
		default:
			usage(basename(argv[0]));
			return 1;
		}
	}

	if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
		xdp_flags |= XDP_FLAGS_DRV_MODE;

	if (optind == argc) {
		usage(basename(argv[0]));
		return 1;
	}

	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);

	obj = bpf_object__open_file(filename, NULL);
	if (libbpf_get_error(obj))
		return 1;

	prog = bpf_object__next_program(obj, NULL);
	bpf_program__set_type(prog, BPF_PROG_TYPE_XDP);

	err = bpf_object__load(obj);
	if (err)
		return 1;

	prog_fd = bpf_program__fd(prog);

	map = bpf_object__next_map(obj, NULL);
	if (!map) {
		printf("finding a map in obj file failed\n");
		return 1;
	}
	map_fd = bpf_map__fd(map);

	if_idx = if_nametoindex(argv[optind]);
	if (!if_idx)
		if_idx = strtoul(argv[optind], NULL, 0);

	if (!if_idx) {
		fprintf(stderr, "Invalid ifname\n");
		return 1;
	}
	if_name = argv[optind];
	err = do_attach(if_idx, prog_fd, if_name);
	if (err)
		return err;

	if (signal(SIGINT, sig_handler) ||
	    signal(SIGHUP, sig_handler) ||
	    signal(SIGTERM, sig_handler)) {
		perror("signal");
		return 1;
	}

	pb = perf_buffer__new(map_fd, 8, print_bpf_output, NULL, NULL, NULL);
	err = libbpf_get_error(pb);
	if (err) {
		perror("perf_buffer setup failed");
		return 1;
	}

	while ((ret = perf_buffer__poll(pb, 1000)) >= 0) {
	}

	kill(0, SIGINT);
	return ret;
}