112 lines
4.4 KiB
JavaScript
112 lines
4.4 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.GDBProtocolWriter = exports.GDBProtocolReader = exports.GDBProtocolClient = void 0;
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const Debug = require("debug");
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const protocol_1 = require("./protocol");
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const debug = Debug('native-run:ios:lib:protocol:gdb');
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const ACK_SUCCESS = '+'.charCodeAt(0);
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class GDBProtocolClient extends protocol_1.ProtocolClient {
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constructor(socket) {
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super(socket, new protocol_1.ProtocolReaderFactory(GDBProtocolReader), new GDBProtocolWriter());
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}
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}
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exports.GDBProtocolClient = GDBProtocolClient;
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class GDBProtocolReader extends protocol_1.ProtocolReader {
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constructor(callback) {
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super(1 /* "Header" is '+' or '-' */, callback);
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}
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onData(data) {
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// the GDB protocol does not support body length in its header so we cannot rely on
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// the parent implementation to determine when a payload is complete
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try {
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// if there's data, add it to the existing buffer
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this.buffer = data ? Buffer.concat([this.buffer, data]) : this.buffer;
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// do we have enough bytes to proceed
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if (this.buffer.length < this.headerSize) {
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return; // incomplete header, wait for more
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}
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// first, check the header
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if (this.parseHeader(this.buffer) === -1) {
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// we have a valid header so check the body. GDB packets will always be a leading '$', data bytes,
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// a trailing '#', and a two digit checksum. minimum valid body is the empty response '$#00'
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// https://developer.apple.com/library/archive/documentation/DeveloperTools/gdb/gdb/gdb_33.html
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const packetData = this.buffer.toString().match('\\$.*#[0-9a-f]{2}');
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if (packetData == null) {
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return; // incomplete body, wait for more
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}
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// extract the body and update the buffer
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const body = Buffer.from(packetData[0]);
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this.buffer = this.buffer.slice(this.headerSize + body.length);
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// parse the payload and recurse if there is more data to process
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this.callback(this.parseBody(body));
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if (this.buffer.length) {
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this.onData();
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}
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}
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}
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catch (err) {
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this.callback(null, err);
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}
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}
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parseHeader(data) {
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if (data[0] !== ACK_SUCCESS) {
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throw new Error('Unsuccessful debugserver response');
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} // TODO: retry?
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return -1;
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}
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parseBody(buffer) {
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debug(`Response body: ${buffer.toString()}`);
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// check for checksum
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const checksum = buffer.slice(-3).toString();
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if (checksum.match(/#[0-9a-f]{2}/)) {
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// remove '$' prefix and checksum
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const msg = buffer.slice(1, -3).toString();
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if (validateChecksum(checksum, msg)) {
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return msg;
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}
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else {
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throw new Error('Invalid checksum received from debugserver');
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}
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}
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else {
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throw new Error("Didn't receive checksum");
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}
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}
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}
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exports.GDBProtocolReader = GDBProtocolReader;
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class GDBProtocolWriter {
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write(socket, msg) {
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const { cmd, args } = msg;
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debug(`Socket write: ${cmd}, args: ${args}`);
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// hex encode and concat all args
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const encodedArgs = args
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.map((arg) => Buffer.from(arg).toString('hex'))
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.join()
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.toUpperCase();
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const checksumStr = calculateChecksum(cmd + encodedArgs);
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const formattedCmd = `$${cmd}${encodedArgs}#${checksumStr}`;
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socket.write(formattedCmd);
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}
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}
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exports.GDBProtocolWriter = GDBProtocolWriter;
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// hex value of (sum of cmd chars mod 256)
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function calculateChecksum(cmdStr) {
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let checksum = 0;
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for (let i = 0; i < cmdStr.length; i++) {
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checksum += cmdStr.charCodeAt(i);
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}
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let result = (checksum % 256).toString(16);
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// pad if necessary
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if (result.length === 1) {
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result = `0${result}`;
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}
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return result;
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}
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function validateChecksum(checksum, msg) {
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// remove '#' from checksum
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const checksumVal = checksum.slice(1);
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// remove '$' from msg and calculate its checksum
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const computedChecksum = calculateChecksum(msg);
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debug(`Checksum: ${checksumVal}, computed checksum: ${computedChecksum}`);
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return checksumVal === computedChecksum;
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}
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