static int bpf_prog_load()

in lcc/glcc/lib/ebpf/ebpf.c [1281:1402]

• 79 lines of code
• 27 McCabe index (conditional complexity)

static int bpf_prog_load(union bpf_attr *attr)
{
	enum bpf_prog_type type = attr->prog_type;
	struct bpf_prog *prog;
	int err;
	char license[128];
	bool is_gpl;

	/* RHEL7 - allow only following types */
	if (type != BPF_PROG_TYPE_KPROBE &&
	    type != BPF_PROG_TYPE_TRACEPOINT &&
	    type != BPF_PROG_TYPE_PERF_EVENT &&
	    !is_test_type(type))
		return -EINVAL;

	if (CHECK_ATTR(BPF_PROG_LOAD))
		return -EINVAL;

	if (attr->prog_flags & ~BPF_F_STRICT_ALIGNMENT)
		return -EINVAL;
	/* copy eBPF program license from user space */
	if (strncpy_from_user(license, u64_to_user_ptr(attr->license),
			      sizeof(license) - 1) < 0)
		return -EFAULT;
	license[sizeof(license) - 1] = 0;

	/* eBPF programs must be GPL compatible to use GPL-ed functions */
	is_gpl = license_is_gpl_compatible(license);

	if (attr->insn_cnt == 0 || attr->insn_cnt > BPF_MAXINSNS)
		return -E2BIG;

	if (type == BPF_PROG_TYPE_KPROBE &&
	    attr->kern_version != LINUX_VERSION_CODE)
		return -EINVAL;

	if (type != BPF_PROG_TYPE_SOCKET_FILTER &&
	    type != BPF_PROG_TYPE_CGROUP_SKB &&
	    !capable(CAP_SYS_ADMIN))
		return -EPERM;

	if (bpf_prog_load_check_attach_type(type, attr->expected_attach_type))
		return -EINVAL;

	/* plain bpf_prog allocation */
	prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
	if (!prog)
		return -ENOMEM;
	prog->expected_attach_type = attr->expected_attach_type;

	// err = security_bpf_prog_alloc(prog->aux);
	// if (err)
	// 	goto free_prog_nouncharge;

	err = bpf_prog_charge_memlock(prog);
	if (err)
		goto free_prog_sec;

	prog->len = attr->insn_cnt;

	err = -EFAULT;
	if (copy_from_user(prog->insns, u64_to_user_ptr(attr->insns),
			   bpf_prog_insn_size(prog)) != 0)
		goto free_prog;

	prog->orig_prog = NULL;
	prog->jited = 0;

	atomic_set(&prog->aux->refcnt, 1);
	prog->gpl_compatible = is_gpl ? 1 : 0;

	/* find program type: socket_filter vs tracing_filter */
	err = find_prog_type(type, prog);
	if (err < 0)
		goto free_prog;

	// prog->aux->load_time = ktime_get_boot_ns();
	err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name);
	if (err)
		goto free_prog;

	/* run eBPF verifier */
	err = bpf_check(&prog, attr);
	if (err < 0)
		goto free_used_maps;

	/* eBPF program is ready to be JITed */
	if (!prog->bpf_func)
		prog = bpf_prog_select_runtime(prog, &err);
	if (err < 0)
		goto free_used_maps;

	err = bpf_prog_alloc_id(prog);
	if (err)
		goto free_used_maps;

	err = bpf_prog_new_fd(prog);
	if (err < 0) {
		/* failed to allocate fd.
		 * bpf_prog_put() is needed because the above
		 * bpf_prog_alloc_id() has published the prog
		 * to the userspace and the userspace may
		 * have refcnt-ed it through BPF_PROG_GET_FD_BY_ID.
		 */
		bpf_prog_put(prog);
		return err;
	}

	// bpf_prog_kallsyms_add(prog);
	return err;

free_used_maps:
	// bpf_prog_kallsyms_del_subprogs(prog);
	free_used_maps(prog->aux);
free_prog:
	bpf_prog_uncharge_memlock(prog);
free_prog_sec:
	// security_bpf_prog_free(prog->aux);
free_prog_nouncharge:
	bpf_prog_free(prog);
	return err;
}