MCP GDB Server

Instructions

Implementation Reference

• src/index.ts:501-558 (handler)

  The handler function that executes the gdb_load tool logic: loads a program into an existing GDB session using the 'file' GDB command and sets program arguments if provided.
  private async handleGdbLoad(args: any) { const { sessionId, program, arguments: programArgs = [] } = args; if (!activeSessions.has(sessionId)) { return { content: [ { type: 'text', text: `No active GDB session with ID: ${sessionId}` } ], isError: true }; } const session = activeSessions.get(sessionId)!; try { // Normalize path if working directory is set const normalizedPath = session.workingDir && !path.isAbsolute(program) ? path.resolve(session.workingDir, program) : program; // Update session target session.target = normalizedPath; // Execute file command to load program const loadCommand = `file "${normalizedPath}"`; const loadOutput = await this.executeGdbCommand(session, loadCommand); // Set program arguments if provided let argsOutput = ''; if (programArgs.length > 0) { const argsCommand = `set args ${programArgs.join(' ')}`; argsOutput = await this.executeGdbCommand(session, argsCommand); } return { content: [ { type: 'text', text: `Program loaded: ${normalizedPath}\n\nOutput:\n${loadOutput}${argsOutput ? '\n' + argsOutput : ''}` } ] }; } catch (error) { const errorMessage = error instanceof Error ? error.message : String(error); return { content: [ { type: 'text', text: `Failed to load program: ${errorMessage}` } ], isError: true }; } }
• src/index.ts:79-101 (schema)

  Tool schema definition including name, description, and input schema with required sessionId and program, optional arguments array.
  name: 'gdb_load', description: 'Load a program into GDB', inputSchema: { type: 'object', properties: { sessionId: { type: 'string', description: 'GDB session ID' }, program: { type: 'string', description: 'Path to the program to debug' }, arguments: { type: 'array', items: { type: 'string' }, description: 'Command-line arguments for the program (optional)' } }, required: ['sessionId', 'program'] }
• src/index.ts:361-362 (registration)

  Registration of the gdb_load tool handler in the CallToolRequestSchema switch statement.
  case 'gdb_load': return await this.handleGdbLoad(request.params.arguments);
• src/index.ts:1159-1217 (helper)

  Helper function executeGdbCommand used by gdb_load to send commands to GDB and capture output.
  private executeGdbCommand(session: GdbSession, command: string): Promise<string> { return new Promise<string>((resolve, reject) => { if (!session.ready) { reject(new Error('GDB session is not ready')); return; } // Write command to GDB's stdin if (session.process.stdin) { session.process.stdin.write(command + '\n'); } else { reject(new Error('GDB stdin is not available')); return; } let output = ''; let responseComplete = false; // Create a one-time event handler for GDB output const onLine = (line: string) => { output += line + '\n'; // Check if this line indicates the end of the GDB response if (line.includes('(gdb)') || line.includes('^done') || line.includes('^error')) { responseComplete = true; // If we've received the complete response, resolve the promise if (responseComplete) { // Remove the listener to avoid memory leaks session.rl.removeListener('line', onLine); resolve(output); } } }; // Add the line handler to the readline interface session.rl.on('line', onLine); // Set a timeout to prevent hanging const timeout = setTimeout(() => { session.rl.removeListener('line', onLine); reject(new Error('GDB command timed out')); }, 10000); // 10 second timeout // Handle GDB errors const errorHandler = (data: Buffer) => { const errorText = data.toString(); output += `[stderr] ${errorText}\n`; }; // Add error handler if (session.process.stderr) { session.process.stderr.once('data', errorHandler); } // Clean up event handlers when the timeout expires timeout.unref(); }); }