int bpf_prog_load_v0_6_0()

in compile/remote-compile/lbc/libbpf/src/bpf.c [240:383]

• 112 lines of code
• 28 McCabe index (conditional complexity)

int bpf_prog_load_v0_6_0(enum bpf_prog_type prog_type,
		         const char *prog_name, const char *license,
		         const struct bpf_insn *insns, size_t insn_cnt,
		         const struct bpf_prog_load_opts *opts)
{
	void *finfo = NULL, *linfo = NULL;
	const char *func_info, *line_info;
	__u32 log_size, log_level, attach_prog_fd, attach_btf_obj_fd;
	__u32 func_info_rec_size, line_info_rec_size;
	int fd, attempts;
	union bpf_attr attr;
	char *log_buf;

	if (!OPTS_VALID(opts, bpf_prog_load_opts))
		return libbpf_err(-EINVAL);

	attempts = OPTS_GET(opts, attempts, 0);
	if (attempts < 0)
		return libbpf_err(-EINVAL);
	if (attempts == 0)
		attempts = PROG_LOAD_ATTEMPTS;

	memset(&attr, 0, sizeof(attr));

	attr.prog_type = prog_type;
	attr.expected_attach_type = OPTS_GET(opts, expected_attach_type, 0);

	attr.prog_btf_fd = OPTS_GET(opts, prog_btf_fd, 0);
	attr.prog_flags = OPTS_GET(opts, prog_flags, 0);
	attr.prog_ifindex = OPTS_GET(opts, prog_ifindex, 0);
	attr.kern_version = OPTS_GET(opts, kern_version, 0);

	if (prog_name)
		strncat(attr.prog_name, prog_name, sizeof(attr.prog_name) - 1);
	attr.license = ptr_to_u64(license);

	if (insn_cnt > UINT_MAX)
		return libbpf_err(-E2BIG);

	attr.insns = ptr_to_u64(insns);
	attr.insn_cnt = (__u32)insn_cnt;

	attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
	attach_btf_obj_fd = OPTS_GET(opts, attach_btf_obj_fd, 0);

	if (attach_prog_fd && attach_btf_obj_fd)
		return libbpf_err(-EINVAL);

	attr.attach_btf_id = OPTS_GET(opts, attach_btf_id, 0);
	if (attach_prog_fd)
		attr.attach_prog_fd = attach_prog_fd;
	else
		attr.attach_btf_obj_fd = attach_btf_obj_fd;

	log_buf = OPTS_GET(opts, log_buf, NULL);
	log_size = OPTS_GET(opts, log_size, 0);
	log_level = OPTS_GET(opts, log_level, 0);

	if (!!log_buf != !!log_size)
		return libbpf_err(-EINVAL);
	if (log_level > (4 | 2 | 1))
		return libbpf_err(-EINVAL);
	if (log_level && !log_buf)
		return libbpf_err(-EINVAL);

	attr.log_level = log_level;
	attr.log_buf = ptr_to_u64(log_buf);
	attr.log_size = log_size;

	func_info_rec_size = OPTS_GET(opts, func_info_rec_size, 0);
	func_info = OPTS_GET(opts, func_info, NULL);
	attr.func_info_rec_size = func_info_rec_size;
	attr.func_info = ptr_to_u64(func_info);
	attr.func_info_cnt = OPTS_GET(opts, func_info_cnt, 0);

	line_info_rec_size = OPTS_GET(opts, line_info_rec_size, 0);
	line_info = OPTS_GET(opts, line_info, NULL);
	attr.line_info_rec_size = line_info_rec_size;
	attr.line_info = ptr_to_u64(line_info);
	attr.line_info_cnt = OPTS_GET(opts, line_info_cnt, 0);

	attr.fd_array = ptr_to_u64(OPTS_GET(opts, fd_array, NULL));

	fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
	if (fd >= 0)
		return fd;

	/* After bpf_prog_load, the kernel may modify certain attributes
	 * to give user space a hint how to deal with loading failure.
	 * Check to see whether we can make some changes and load again.
	 */
	while (errno == E2BIG && (!finfo || !linfo)) {
		if (!finfo && attr.func_info_cnt &&
		    attr.func_info_rec_size < func_info_rec_size) {
			/* try with corrected func info records */
			finfo = alloc_zero_tailing_info(func_info,
							attr.func_info_cnt,
							func_info_rec_size,
							attr.func_info_rec_size);
			if (!finfo) {
				errno = E2BIG;
				goto done;
			}

			attr.func_info = ptr_to_u64(finfo);
			attr.func_info_rec_size = func_info_rec_size;
		} else if (!linfo && attr.line_info_cnt &&
			   attr.line_info_rec_size < line_info_rec_size) {
			linfo = alloc_zero_tailing_info(line_info,
							attr.line_info_cnt,
							line_info_rec_size,
							attr.line_info_rec_size);
			if (!linfo) {
				errno = E2BIG;
				goto done;
			}

			attr.line_info = ptr_to_u64(linfo);
			attr.line_info_rec_size = line_info_rec_size;
		} else {
			break;
		}

		fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
		if (fd >= 0)
			goto done;
	}

	if (log_level || !log_buf)
		goto done;

	/* Try again with log */
	log_buf[0] = 0;
	attr.log_buf = ptr_to_u64(log_buf);
	attr.log_size = log_size;
	attr.log_level = 1;

	fd = sys_bpf_prog_load(&attr, sizeof(attr), attempts);
done:
	/* free() doesn't affect errno, so we don't need to restore it */
	free(finfo);
	free(linfo);
	return libbpf_err_errno(fd);
}