Repository: nodejs/node
Pull request: src: fix kill signal on Windows

> On Windows, where POSIX signals do not exist, the signal argument will be ignored, and the process will be killed forcefully and abruptly (similar to 'SIGKILL')

As stated in [the documentation](https://nodejs.org/api/child_process.html#subprocesskillsignal) of Node.js, the `signal` parameter of child process `kill` function is ignored.

However, when we execute `spawn(process.execPath, ['-v']).kill('SIGHUP');`, it throws an exception with the code `ENOSYS`. This is not consistent with the documentation.

I've looked at the implementation in libuv and have seen that only [four signal types](https://github.com/libuv/libuv/blob/d4ab6fbba4669935a6bc23645372dfe4ac29ab39/src/win/process.c#L1285-L1288) are supported to kill a process on Windows. 

This PR fixes this issue by changing the signal to `SIGKILL` if it differs from `SIGQUIT`, `SIGTERM`, `SIGKILL`, and `SIGINT`.  In addition, there is a slight change in the documentation to clarify the `signal` parameter.

Fixes: https://github.com/nodejs/node/issues/42923

<!--
Before submitting a pull request, please read:

- the CONTRIBUTING guide at https://github.com/nodejs/node/blob/HEAD/CONTRIBUTING.md
- the commit message formatting guidelines at
  https://github.com/nodejs/node/blob/HEAD/doc/contributing/pull-requests.md#commit-message-guidelines

For code changes:
1. Include tests for any bug fixes or new features.
2. Update documentation if relevant.
3. Ensure that `make -j4 test` (UNIX), or `vcbuild test` (Windows) passes.

If you believe this PR should be highlighted in the Node.js CHANGELOG
please add the `notable-change` label.

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified
    it.

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.
-->


Changed files:
filename: doc/api/child_process.md
patch: @@ -1700,8 +1700,8 @@ may not actually terminate the process.
 See kill(2) for reference.
 
 On Windows, where POSIX signals do not exist, the `signal` argument will be
-ignored, and the process will be killed forcefully and abruptly (similar to
-`'SIGKILL'`).
+ignored except for `'SIGKILL'`, `'SIGTERM'`, `'SIGINT'` and `'SIGQUIT'`, and the
+process will always be killed forcefully and abruptly (similar to `'SIGKILL'`).
 See [Signal Events][] for more details.
 
 On Linux, child processes of child processes will not be terminated

filename: src/process_wrap.cc
patch: @@ -314,6 +314,12 @@ class ProcessWrap : public HandleWrap {
     ProcessWrap* wrap;
     ASSIGN_OR_RETURN_UNWRAP(&wrap, args.This());
     int signal = args[0]->Int32Value(env->context()).FromJust();
+#ifdef _WIN32
+    if (signal != SIGKILL && signal != SIGTERM && signal != SIGINT &&
+        signal != SIGQUIT) {
+      signal = SIGKILL;
+    }
+#endif
     int err = uv_process_kill(&wrap->process_, signal);
     args.GetReturnValue().Set(err);
   }

filename: test/parallel/test-child-process-kill.js
patch: @@ -39,3 +39,22 @@ assert.strictEqual(cat.signalCode, null);
 assert.strictEqual(cat.killed, false);
 cat.kill();
 assert.strictEqual(cat.killed, true);
+
+// Test different types of kill signals on Windows.
+if (common.isWindows) {
+  for (const sendSignal of ['SIGTERM', 'SIGKILL', 'SIGQUIT', 'SIGINT']) {
+    const process = spawn('cmd');
+    process.on('exit', (code, signal) => {
+      assert.strictEqual(code, null);
+      assert.strictEqual(signal, sendSignal);
+    });
+    process.kill(sendSignal);
+  }
+
+  const process = spawn('cmd');
+  process.on('exit', (code, signal) => {
+    assert.strictEqual(code, null);
+    assert.strictEqual(signal, 'SIGKILL');
+  });
+  process.kill('SIGHUP');
+}