XDR encoded nvpairs sample code

nvs_xdr_nvpair.c

static int
nvs_xdr_nvpair(nvstream_t *nvs, nvpair_t *nvp, size_t *size)
{
	XDR 	*xdr = nvs->nvs_private;
	int32_t	encode_len, decode_len;

	switch (nvs->nvs_op) {
	case NVS_OP_ENCODE: {
		size_t nvsize;

		if (nvs_xdr_nvp_size(nvs, nvp, &nvsize) != 0)
			return (EFAULT);

		decode_len = nvp->nvp_size;
		encode_len = nvsize;
		if (!xdr_int(xdr, &encode_len) || !xdr_int(xdr, &decode_len))
			return (EFAULT);

		return (nvs_xdr_nvp_op(nvs, nvp));
	}
	case NVS_OP_DECODE: {
		struct xdr_bytesrec bytesrec;

		/* get the encode and decode size */
		if (!xdr_int(xdr, &encode_len) || !xdr_int(xdr, &decode_len))
			return (EFAULT);
		*size = decode_len;

		/* are we at the end of the stream? */
		if (*size == 0)
			return (0);

		/* sanity check the size parameter */
		if (!xdr_control(xdr, XDR_GET_BYTES_AVAIL, &bytesrec))
			return (EFAULT);

		if (*size > NVS_XDR_MAX_LEN(bytesrec.xc_num_avail))
			return (EFAULT);
		break;
	}

	default:
		return (EINVAL);
	}
	return (0);
}