int main()

in bpf/sampleip_user.c [139:227]
71 lines of code
15 McCabe index (conditional complexity)

int main(int argc, char **argv)
{
	int opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS, error = 1;
	struct bpf_object *obj = NULL;
	struct bpf_program *prog;
	struct bpf_link **links;
	char filename[256];

	/* process arguments */
	while ((opt = getopt(argc, argv, "F:h")) != -1) {
		switch (opt) {
		case 'F':
			freq = atoi(optarg);
			break;
		case 'h':
		default:
			usage();
			return 0;
		}
	}
	if (argc - optind == 1)
		secs = atoi(argv[optind]);
	if (freq == 0 || secs == 0) {
		usage();
		return 1;
	}

	/* initialize kernel symbol translation */
	if (load_kallsyms()) {
		fprintf(stderr, "ERROR: loading /proc/kallsyms\n");
		return 2;
	}

	/* create perf FDs for each CPU */
	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
	links = calloc(nr_cpus, sizeof(struct bpf_link *));
	if (!links) {
		fprintf(stderr, "ERROR: malloc of links\n");
		goto cleanup;
	}

	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
	obj = bpf_object__open_file(filename, NULL);
	if (libbpf_get_error(obj)) {
		fprintf(stderr, "ERROR: opening BPF object file failed\n");
		obj = NULL;
		goto cleanup;
	}

	prog = bpf_object__find_program_by_name(obj, "do_sample");
	if (!prog) {
		fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
		goto cleanup;
	}

	/* load BPF program */
	if (bpf_object__load(obj)) {
		fprintf(stderr, "ERROR: loading BPF object file failed\n");
		goto cleanup;
	}

	map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
	if (map_fd < 0) {
		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
		goto cleanup;
	}

	signal(SIGINT, int_exit);
	signal(SIGTERM, int_exit);

	/* do sampling */
	printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
	       freq, secs);
	if (sampling_start(freq, prog, links) != 0)
		goto cleanup;

	sleep(secs);
	error = 0;

cleanup:
	sampling_end(links);
	/* output sample counts */
	if (!error)
		print_ip_map(map_fd);

	free(links);
	bpf_object__close(obj);
	return error;
}