static int probe_prog_load()

in contrib/libbpf/src/libbpf_probes.c [103:200]

• 94 lines of code
• 42 McCabe index (conditional complexity)

static int probe_prog_load(enum bpf_prog_type prog_type,
			   const struct bpf_insn *insns, size_t insns_cnt,
			   char *log_buf, size_t log_buf_sz)
{
	LIBBPF_OPTS(bpf_prog_load_opts, opts,
		.log_buf = log_buf,
		.log_size = log_buf_sz,
		.log_level = log_buf ? 1 : 0,
	);
	int fd, err, exp_err = 0;
	const char *exp_msg = NULL;
	char buf[4096];

	switch (prog_type) {
	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
		opts.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
		break;
	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
		opts.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
		break;
	case BPF_PROG_TYPE_SK_LOOKUP:
		opts.expected_attach_type = BPF_SK_LOOKUP;
		break;
	case BPF_PROG_TYPE_KPROBE:
		opts.kern_version = get_kernel_version();
		break;
	case BPF_PROG_TYPE_LIRC_MODE2:
		opts.expected_attach_type = BPF_LIRC_MODE2;
		break;
	case BPF_PROG_TYPE_TRACING:
	case BPF_PROG_TYPE_LSM:
		opts.log_buf = buf;
		opts.log_size = sizeof(buf);
		opts.log_level = 1;
		if (prog_type == BPF_PROG_TYPE_TRACING)
			opts.expected_attach_type = BPF_TRACE_FENTRY;
		else
			opts.expected_attach_type = BPF_MODIFY_RETURN;
		opts.attach_btf_id = 1;

		exp_err = -EINVAL;
		exp_msg = "attach_btf_id 1 is not a function";
		break;
	case BPF_PROG_TYPE_EXT:
		opts.log_buf = buf;
		opts.log_size = sizeof(buf);
		opts.log_level = 1;
		opts.attach_btf_id = 1;

		exp_err = -EINVAL;
		exp_msg = "Cannot replace kernel functions";
		break;
	case BPF_PROG_TYPE_SYSCALL:
		opts.prog_flags = BPF_F_SLEEPABLE;
		break;
	case BPF_PROG_TYPE_STRUCT_OPS:
		exp_err = -524; /* -ENOTSUPP */
		break;
	case BPF_PROG_TYPE_UNSPEC:
	case BPF_PROG_TYPE_SOCKET_FILTER:
	case BPF_PROG_TYPE_SCHED_CLS:
	case BPF_PROG_TYPE_SCHED_ACT:
	case BPF_PROG_TYPE_TRACEPOINT:
	case BPF_PROG_TYPE_XDP:
	case BPF_PROG_TYPE_PERF_EVENT:
	case BPF_PROG_TYPE_CGROUP_SKB:
	case BPF_PROG_TYPE_CGROUP_SOCK:
	case BPF_PROG_TYPE_LWT_IN:
	case BPF_PROG_TYPE_LWT_OUT:
	case BPF_PROG_TYPE_LWT_XMIT:
	case BPF_PROG_TYPE_SOCK_OPS:
	case BPF_PROG_TYPE_SK_SKB:
	case BPF_PROG_TYPE_CGROUP_DEVICE:
	case BPF_PROG_TYPE_SK_MSG:
	case BPF_PROG_TYPE_RAW_TRACEPOINT:
	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
	case BPF_PROG_TYPE_SK_REUSEPORT:
	case BPF_PROG_TYPE_FLOW_DISSECTOR:
	case BPF_PROG_TYPE_CGROUP_SYSCTL:
		break;
	default:
		return -EOPNOTSUPP;
	}

	fd = bpf_prog_load(prog_type, NULL, "GPL", insns, insns_cnt, &opts);
	err = -errno;
	if (fd >= 0)
		close(fd);
	if (exp_err) {
		if (fd >= 0 || err != exp_err)
			return 0;
		if (exp_msg && !strstr(buf, exp_msg))
			return 0;
		return 1;
	}
	return fd >= 0 ? 1 : 0;
}