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Commit f430140f authored by Yan Han's avatar Yan Han
Browse files

Validate all messages on construction 

Refactors message validation in preparation for letting messages have
their own class:
- HdmiCecMessage is now built using a static factory method, which
validates the message and stores the result in an instance variable.
- HdmiCecMessageValidator is now static to remove its dependence on
HdmiControlService and allow HdmiCecMessage construction to use it.
- To achieve this, validation steps that are dependent on a
HdmiControlService instance are now done in HdmiControlService instead.
These are really verification steps instead of validation steps, as they
depend on the state a specific CEC network - for example, they include
checks for whether a physical address has a valid port on a local TV
device.

Change-Id: I5e8c0bbeb7069e3b5cc797d6fe98470ecddda438
Bug: 207359637
Test: atest com.android.server.hdmi
parent abbbf2ae

services/core/java/com/android/server/hdmi/HdmiCecController.java

+14 −1
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ import libcore.util.EmptyArray; 


import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Date;

import java.util.LinkedList;

import java.util.List;
@@ -694,7 +695,19 @@ final class HdmiCecController { 
    @ServiceThreadOnly

    private void handleIncomingCecCommand(int srcAddress, int dstAddress, byte[] body) {

        assertRunOnServiceThread();

        HdmiCecMessage command = HdmiCecMessageBuilder.of(srcAddress, dstAddress, body);



        if (body.length == 0) {

            Slog.e(TAG, "Message with empty body received.");

            return;

        }



        HdmiCecMessage command = HdmiCecMessage.build(srcAddress, dstAddress, body[0],

                Arrays.copyOfRange(body, 1, body.length));



        if (command.getValidationResult() != HdmiCecMessageValidator.OK) {

            Slog.e(TAG, "Invalid message received: " + command);

        }



        HdmiLogger.debug("[R]:" + command);

        addCecMessageToHistory(true /* isReceived */, command);

services/core/java/com/android/server/hdmi/HdmiCecMessage.java

+71 −10
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 


package com.android.server.hdmi;



import static com.android.server.hdmi.HdmiCecMessageValidator.ValidationResult;



import android.annotation.Nullable;



import com.android.server.hdmi.Constants.FeatureOpcode;
@@ -26,11 +28,13 @@ import java.util.Arrays; 
import java.util.Objects;



/**

 * A class to encapsulate HDMI-CEC message used for the devices connected via

 * HDMI cable to communicate with one another. A message is defined by its

 * source and destination address, command (or opcode), and optional parameters.

 * Encapsulates the data that defines an HDMI-CEC message: source and destination address,

 * command (or opcode), and optional parameters. Also stores the result of validating the message.

 *

 * Subclasses of this class represent specific messages that have been validated, and expose their

 * parsed parameters.

 */

public final class HdmiCecMessage {

public class HdmiCecMessage {

    public static final byte[] EMPTY_PARAM = EmptyArray.BYTE;



    private final int mSource;
@@ -39,24 +43,53 @@ public final class HdmiCecMessage { 
    private final int mOpcode;

    private final byte[] mParams;



    private final int mValidationResult;



    /**

     * Constructor.

     * Constructor that allows the caller to provide the validation result.

     * Must only be called by subclasses; other callers should use {@link #build}.

     */

    public HdmiCecMessage(int source, int destination, int opcode, byte[] params) {

    protected HdmiCecMessage(int source, int destination, int opcode, byte[] params,

            @ValidationResult int validationResult) {

        mSource = source;

        mDestination = destination;

        mOpcode = opcode & 0xFF;

        mParams = Arrays.copyOf(params, params.length);

        mValidationResult = validationResult;

    }



    private HdmiCecMessage(int source, int destination, int opcode, byte[] params) {

        this(source, destination, opcode, params,

                HdmiCecMessageValidator.validate(source, destination, opcode & 0xFF, params));

    }



    /**

     * Constructs and validates a message. The result of validation will be accessible via

     * {@link #getValidationResult}.

     *

     * Intended for parsing incoming messages, as it takes raw bytes as message parameters.

     *

     * If the opcode has its own subclass of this one, this method will instead validate and build

     * the message using the logic in that class. If successful, it will return a validated

     * instance of that class that exposes parsed parameters.

     */

    static HdmiCecMessage build(int source, int destination, int opcode, byte[] params) {

        return new HdmiCecMessage(source, destination, opcode, params);

    }



    static HdmiCecMessage build(int source, int destination, int opcode) {

        return new HdmiCecMessage(source, destination, opcode, EMPTY_PARAM);

    }



    @Override

    public boolean equals(@Nullable Object message) {

        if (message instanceof HdmiCecMessage) {

            HdmiCecMessage that = (HdmiCecMessage) message;

            return this.mSource == that.getSource() &&

                this.mDestination == that.getDestination() &&

                this.mOpcode == that.getOpcode() &&

                Arrays.equals(this.mParams, that.getParams());

            return this.mSource == that.getSource()

                    && this.mDestination == that.getDestination()

                    && this.mOpcode == that.getOpcode()

                    && Arrays.equals(this.mParams, that.getParams())

                    && this.mValidationResult == that.getValidationResult();

        }

        return false;

    }
@@ -111,6 +144,13 @@ public final class HdmiCecMessage { 
        return mParams;

    }



    /**

     * Returns the validation result of the message.

     */

    public int getValidationResult() {

        return mValidationResult;

    }



    @Override

    public String toString() {

        StringBuilder s = new StringBuilder();
@@ -129,9 +169,30 @@ public final class HdmiCecMessage { 
                }

            }

        }

        if (mValidationResult != HdmiCecMessageValidator.OK) {

            s.append(String.format(" <Validation error: %s>",

                    validationResultToString(mValidationResult)));

        }

        return s.toString();

    }



    private static String validationResultToString(@ValidationResult int validationResult) {

        switch (validationResult) {

            case HdmiCecMessageValidator.OK:

                return "ok";

            case HdmiCecMessageValidator.ERROR_SOURCE:

                return "invalid source";

            case HdmiCecMessageValidator.ERROR_DESTINATION:

                return "invalid destination";

            case HdmiCecMessageValidator.ERROR_PARAMETER:

                return "invalid parameters";

            case HdmiCecMessageValidator.ERROR_PARAMETER_SHORT:

                return "short parameters";

            default:

                return "unknown error";

        }

    }



    private static String opcodeToString(@FeatureOpcode int opcode) {

        switch (opcode) {

            case Constants.MESSAGE_FEATURE_ABORT:

services/core/java/com/android/server/hdmi/HdmiCecMessageBuilder.java

+56 −88

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services/core/java/com/android/server/hdmi/HdmiCecMessageValidator.java

+106 −105

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services/core/java/com/android/server/hdmi/HdmiControlService.java

+88 −18

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