static int qmi_decode()

in qcom/qmi_encdec.c [593:702]

• 96 lines of code
• 24 McCabe index (conditional complexity)

static int qmi_decode(struct qmi_elem_info *ei_array, void *out_c_struct,
		      const void *in_buf, u32 in_buf_len,
		      int dec_level)
{
	struct qmi_elem_info *temp_ei = ei_array;
	u8 opt_flag_value = 1;
	u32 data_len_value = 0, data_len_sz = 0;
	u8 *buf_dst = out_c_struct;
	const u8 *tlv_pointer;
	u32 tlv_len = 0;
	u32 tlv_type;
	u32 decoded_bytes = 0;
	const void *buf_src = in_buf;
	int rc;

	while (decoded_bytes < in_buf_len) {
		if (dec_level >= 2 && temp_ei->data_type == QMI_EOTI)
			return decoded_bytes;

		if (dec_level == 1) {
			tlv_pointer = buf_src;
			QMI_ENCDEC_DECODE_TLV(&tlv_type,
					      &tlv_len, tlv_pointer);
			buf_src += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
			decoded_bytes += (TLV_TYPE_SIZE + TLV_LEN_SIZE);
			temp_ei = find_ei(ei_array, tlv_type);
			if (!temp_ei && tlv_type < OPTIONAL_TLV_TYPE_START) {
				pr_err("%s: Inval element info\n", __func__);
				return -EINVAL;
			} else if (!temp_ei) {
				UPDATE_DECODE_VARIABLES(buf_src,
							decoded_bytes, tlv_len);
				continue;
			}
		} else {
			/*
			 * No length information for elements in nested
			 * structures. So use remaining decodable buffer space.
			 */
			tlv_len = in_buf_len - decoded_bytes;
		}

		buf_dst = out_c_struct + temp_ei->offset;
		if (temp_ei->data_type == QMI_OPT_FLAG) {
			memcpy(buf_dst, &opt_flag_value, sizeof(u8));
			temp_ei = temp_ei + 1;
			buf_dst = out_c_struct + temp_ei->offset;
		}

		if (temp_ei->data_type == QMI_DATA_LEN) {
			data_len_sz = temp_ei->elem_size == sizeof(u8) ?
					sizeof(u8) : sizeof(u16);
			rc = qmi_decode_basic_elem(&data_len_value, buf_src,
						   1, data_len_sz);
			memcpy(buf_dst, &data_len_value, sizeof(u32));
			temp_ei = temp_ei + 1;
			buf_dst = out_c_struct + temp_ei->offset;
			tlv_len -= data_len_sz;
			UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
		}

		if (temp_ei->array_type == NO_ARRAY) {
			data_len_value = 1;
		} else if (temp_ei->array_type == STATIC_ARRAY) {
			data_len_value = temp_ei->elem_len;
		} else if (data_len_value > temp_ei->elem_len) {
			pr_err("%s: Data len %d > max spec %d\n",
			       __func__, data_len_value, temp_ei->elem_len);
			return -ETOOSMALL;
		}

		switch (temp_ei->data_type) {
		case QMI_UNSIGNED_1_BYTE:
		case QMI_UNSIGNED_2_BYTE:
		case QMI_UNSIGNED_4_BYTE:
		case QMI_UNSIGNED_8_BYTE:
		case QMI_SIGNED_2_BYTE_ENUM:
		case QMI_SIGNED_4_BYTE_ENUM:
			rc = qmi_decode_basic_elem(buf_dst, buf_src,
						   data_len_value,
						   temp_ei->elem_size);
			UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
			break;

		case QMI_STRUCT:
			rc = qmi_decode_struct_elem(temp_ei, buf_dst, buf_src,
						    data_len_value, tlv_len,
						    dec_level + 1);
			if (rc < 0)
				return rc;
			UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
			break;

		case QMI_STRING:
			rc = qmi_decode_string_elem(temp_ei, buf_dst, buf_src,
						    tlv_len, dec_level);
			if (rc < 0)
				return rc;
			UPDATE_DECODE_VARIABLES(buf_src, decoded_bytes, rc);
			break;

		default:
			pr_err("%s: Unrecognized data type\n", __func__);
			return -EINVAL;
		}
		temp_ei = temp_ei + 1;
	}

	return decoded_bytes;
}