lib: add trace-sigint APIs

Author: theanarkh

doc/api/process.md

@@ -4059,6 +4059,16 @@ This property refers to the value of underlying file descriptor of
 `process.stderr`. The value is fixed at `2`. In [`Worker`][] threads,
 this field does not exist.
 
+## `process.setTraceSigInt(enable)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `enable` {boolean}
+
+Enable or disable printing a stack trace on `SIGINT`. The API is only available on the main thread.
+
 ## `process.stdin`
 
 * {Stream}

lib/internal/process/pre_execution.js

@@ -382,14 +382,28 @@ function setupCodeCoverage() {
   }
 }
 
+
+let sigintWatchdog;
+function getSigintWatchdog() {
+  if (!sigintWatchdog) {
+    const { SigintWatchdog } = require('internal/watchdog');
+    sigintWatchdog = new SigintWatchdog();
+  }
+  return sigintWatchdog;
+}
+
 function setupStacktracePrinterOnSigint() {
+  process.setTraceSigInt = function(enable) {
+    if (enable) {
+      getSigintWatchdog().start();
+    } else {
+      getSigintWatchdog().stop();
+    }
+  };
   if (!getOptionValue('--trace-sigint')) {
     return;
   }
-  const { SigintWatchdog } = require('internal/watchdog');
-
-  const watchdog = new SigintWatchdog();
-  watchdog.start();
+  process.setTraceSigInt(true);
 }
 
 function initializeReport() {

lib/internal/watchdog.js

@@ -53,7 +53,6 @@ class SigintWatchdog extends TraceSigintWatchdog {
   }
 }
 
-
 module.exports = {
   SigintWatchdog,
 };

test/parallel/test-start-trace-sigint.js

@@ -0,0 +1,32 @@
+'use strict';
+
+const { mustCall } = require('../common');
+const childProcess = require('child_process');
+const assert = require('assert');
+
+if (!process.env.CHILD) {
+  const cp = childProcess.spawn(
+    process.execPath,
+    [__filename],
+    {
+      env: { ...process.env, CHILD: '1' },
+    });
+  let data;
+  cp.stderr.on('data', (chunk) => {
+    data = data ? data + chunk : chunk;
+  });
+  cp.stderr.on('end', () => {
+    console.log(data);
+    assert.strictEqual(/SIGINT/.test(data.toString()), true);
+  });
+  cp.on('exit', mustCall((code, signal) => {
+    assert.strictEqual(signal, 'SIGINT');
+    assert.strictEqual(code, null);
+  }));
+} else {
+  process.setTraceSigInt(true);
+  // Deactivate colors even if the tty does support colors.
+  process.env.NODE_DISABLE_COLORS = '1';
+  process.kill(process.pid, 'SIGINT');
+  while (true);
+}

test/parallel/test-stop-trace-sigint.js

@@ -0,0 +1,33 @@
+'use strict';
+
+const { mustCall } = require('../common');
+const childProcess = require('child_process');
+const assert = require('assert');
+
+if (!process.env.CHILD) {
+  {
+    const cp = childProcess.spawn(
+      process.execPath,
+      ['--trace-sigint', __filename],
+      {
+        env: { ...process.env, CHILD: '1' },
+      });
+    let data;
+    cp.stderr.on('data', (chunk) => {
+      data = data ? data + chunk : chunk;
+    });
+    cp.stderr.on('end', () => {
+      assert.strictEqual(data === undefined, true);
+    });
+    cp.on('exit', mustCall((code, signal) => {
+      assert.strictEqual(signal, 'SIGINT');
+      assert.strictEqual(code, null);
+    }));
+  }
+} else {
+  process.setTraceSigInt(false);
+  // Deactivate colors even if the tty does support colors.
+  process.env.NODE_DISABLE_COLORS = '1';
+  process.kill(process.pid, 'SIGINT');
+  while (true);
+}