fix(agent): bound CLI subprocess execution

src/cli/executeCliCommand.ts

@@ -0,0 +1,196 @@
+import { spawn } from "node:child_process";
+
+import { type RuntimeSessionContext } from "../runtime/sessionContext.js";
+
+type OutputStream = "stdout" | "stderr";
+
+export type CliExecutionResult = {
+  outcome: "completed" | "timeout" | "output_limit";
+  exitCode: number | null;
+  signal: NodeJS.Signals | null;
+  status: number;
+  stderr: string;
+  stdout: string;
+  exceededStream?: OutputStream;
+};
+
+type ExecuteCliCommandOptions = {
+  apiBaseUrl: string;
+  cliPath: string;
+  maxOutputBytes: number;
+  terminationGraceMs?: number;
+};
+
+const getCompletedStatus = (exitCode: number | null, stdout: string) => {
+  let errorCode = "";
+  try {
+    const payload = JSON.parse(stdout) as { error?: { code?: unknown } };
+    errorCode =
+      typeof payload.error?.code === "string" ? payload.error.code : "";
+  } catch {
+    errorCode = "";
+  }
+
+  if (errorCode === "HTTP_401" || errorCode === "UNAUTHENTICATED") {
+    return 401;
+  }
+  if (errorCode === "HTTP_403") {
+    return 403;
+  }
+  return exitCode === 0 ? 200 : 502;
+};
+
+export const executeCliCommand = async (
+  context: RuntimeSessionContext,
+  command: string,
+  timeoutSec: number,
+  options: ExecuteCliCommandOptions,
+): Promise<CliExecutionResult> => {
+  const maxOutputBytes = options.maxOutputBytes;
+  if (!Number.isSafeInteger(maxOutputBytes) || maxOutputBytes <= 0) {
+    throw new Error("maxOutputBytes must be a positive safe integer");
+  }
+
+  const child = spawn(
+    options.cliPath,
+    ["--auth-stdin", ...command.split(/\s+/).filter(Boolean)],
+    { stdio: ["pipe", "pipe", "pipe"] },
+  );
+  const stdoutChunks: Buffer[] = [];
+  const stderrChunks: Buffer[] = [];
+  let stdoutBytes = 0;
+  let stderrBytes = 0;
+  let terminationReason:
+    | "timeout"
+    | "output_limit"
+    | "execution_error"
+    | null = null;
+  let exceededStream: OutputStream | undefined;
+  let terminationStarted = false;
+  let settled = false;
+  let executionError: Error | null = null;
+  let forceKillTimer: ReturnType<typeof setTimeout> | undefined;
+
+  const result = await new Promise<CliExecutionResult>((resolve, reject) => {
+    const cleanup = () => {
+      clearTimeout(timeoutTimer);
+      if (forceKillTimer) {
+        clearTimeout(forceKillTimer);
+      }
+    };
+
+    const terminate = (
+      reason: "timeout" | "output_limit" | "execution_error",
+    ) => {
+      if (terminationStarted) {
+        return;
+      }
+      terminationStarted = true;
+      terminationReason = reason;
+
+      if (child.exitCode === null && child.signalCode === null) {
+        child.kill("SIGTERM");
+      }
+      forceKillTimer = setTimeout(() => {
+        if (child.exitCode === null && child.signalCode === null) {
+          child.kill("SIGKILL");
+        }
+      }, options.terminationGraceMs ?? 1500);
+    };
+
+    const capture = (stream: OutputStream, data: Buffer) => {
+      if (terminationReason) {
+        return;
+      }
+      const chunks = stream === "stdout" ? stdoutChunks : stderrChunks;
+      const bytes = stream === "stdout" ? stdoutBytes : stderrBytes;
+      if (bytes + data.length > maxOutputBytes) {
+        exceededStream = stream;
+        terminate("output_limit");
+        return;
+      }
+      chunks.push(data);
+      if (stream === "stdout") {
+        stdoutBytes += data.length;
+      } else {
+        stderrBytes += data.length;
+      }
+    };
+
+    const timeoutTimer = setTimeout(() => {
+      if (child.exitCode === null && child.signalCode === null) {
+        terminate("timeout");
+      }
+    }, timeoutSec * 1000);
+
+    child.stdout.on("data", (data: Buffer) => capture("stdout", data));
+    child.stderr.on("data", (data: Buffer) => capture("stderr", data));
+    child.stdin.on("error", (error) => {
+      if (terminationReason === null) {
+        executionError = error;
+        terminate("execution_error");
+      }
+    });
+    child.on("error", (error) => {
+      if (terminationReason === null) {
+        executionError = error;
+        terminate("execution_error");
+      }
+    });
+    child.on("close", (exitCode, signal) => {
+      if (settled) {
+        return;
+      }
+      settled = true;
+      cleanup();
+      if (terminationReason === "timeout") {
+        resolve({
+          outcome: "timeout",
+          exitCode,
+          signal,
+          status: 504,
+          stderr: "",
+          stdout: "",
+        });
+        return;
+      }
+      if (executionError) {
+        reject(executionError);
+        return;
+      }
+      if (terminationReason === "output_limit") {
+        resolve({
+          outcome: "output_limit",
+          exceededStream,
+          exitCode,
+          signal,
+          status: 502,
+          stderr: "",
+          stdout: "",
+        });
+        return;
+      }
+
+      const stdout = Buffer.concat(stdoutChunks, stdoutBytes).toString("utf-8");
+      const stderr = Buffer.concat(stderrChunks, stderrBytes).toString("utf-8");
+      resolve({
+        outcome: "completed",
+        exitCode,
+        signal,
+        status: getCompletedStatus(exitCode, stdout),
+        stderr,
+        stdout,
+      });
+    });
+
+    child.stdin.end(
+      JSON.stringify({
+        server: options.apiBaseUrl,
+        access_token: context.accessToken,
+        project_id: context.projectId,
+      }),
+    );
+  });
+
+  return result;
+};