From 901ec06ae8e1cda57d4223365c5c1e3f8e7bdee3 Mon Sep 17 00:00:00 2001
From: Pooja Trivedi <trivedipooja@microsoft.com>
Date: Mon, 8 Dec 2025 19:46:23 -0500
Subject: [PATCH] Implement Stop Container

---
 src/windows/wslaservice/exe/WSLAContainer.cpp | 33 ++++++++++++++++++-
 test/windows/WSLATests.cpp                    | 33 +++++++++++++++++++
 2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/src/windows/wslaservice/exe/WSLAContainer.cpp b/src/windows/wslaservice/exe/WSLAContainer.cpp
index 3b770e9..c82cf78 100644
--- a/src/windows/wslaservice/exe/WSLAContainer.cpp
+++ b/src/windows/wslaservice/exe/WSLAContainer.cpp
@@ -69,9 +69,40 @@ HRESULT WSLAContainer::Start()
 }
 
 HRESULT WSLAContainer::Stop(int Signal, ULONG TimeoutMs)
+try
 {
-    return E_NOTIMPL;
+    std::lock_guard lock{m_lock};
+
+    /* 'nerdctl stop ...'
+     *   returns success and <containerId> on stdout if the container is running or already stopped
+     *   returns error "No such container: <containerId>" on stderr if the container is in 'Created' state or does not exist
+     *
+     * For our case, we consider stopping a container that is not running or does not exist as a no-op and return success.
+     * TODO: Discuss and return stdout/stderr or corresponding HRESULT from nerdctl stop for better diagnostics.
+     */
+
+    if (m_state == WslaContainerStateExited)
+    {
+        return S_OK;
+    }
+    // Validate that the container is in the exited state.
+    RETURN_HR_IF_MSG(
+        HRESULT_FROM_WIN32(ERROR_INVALID_STATE),
+        m_state != WslaContainerStateRunning,
+        "No such running or exited container '%hs', state: %i",
+        m_name.c_str(),
+        m_state);
+    ServiceProcessLauncher launcher(nerdctlPath, {nerdctlPath, "stop", m_name});
+    // TODO: Figure out how we want to handle custom signals and timeout values.
+    // nerdctl stop has a --time and a --signal option that can be used
+    // By default, it uses SIGTERM and a default timeout of 10 seconds.
+    auto result = launcher.Launch(*m_parentVM).Wait();
+    THROW_HR_IF(E_FAIL, result.first != 0);
+
+    m_state = WslaContainerStateExited;
+    return S_OK;
 }
+CATCH_RETURN();
 
 HRESULT WSLAContainer::Delete()
 try
diff --git a/test/windows/WSLATests.cpp b/test/windows/WSLATests.cpp
index 031611c..1af0543 100644
--- a/test/windows/WSLATests.cpp
+++ b/test/windows/WSLATests.cpp
@@ -1233,6 +1233,32 @@ class WSLATests
             VERIFY_SUCCEEDED(container.Get().Delete());
         }
 
+        // Test StopContainer
+        {
+            // Create a container
+            WSLAContainerLauncher launcher(
+                "debian:latest", "test-container-2", "/bin/cat", {}, {}, ProcessFlags::Stdin | ProcessFlags::Stdout | ProcessFlags::Stderr);
+
+            auto container = launcher.Launch(*session);
+
+            // Verify that the container is in running state.
+            VERIFY_ARE_EQUAL(container.State(), WslaContainerStateRunning);
+
+            VERIFY_SUCCEEDED(container.Get().Stop(9, 10000));
+
+            expectContainerList(
+                {{"exited-container", "debian:latest", WslaContainerStateExited},
+                 {"test-container-2", "debian:latest", WslaContainerStateExited}});
+
+            // Verify that the container is in exited state.
+            VERIFY_ARE_EQUAL(container.State(), WslaContainerStateExited);
+
+            // Verify that deleting a container stopped via Stop() works.
+            VERIFY_SUCCEEDED(container.Get().Delete());
+
+            expectContainerList({{"exited-container", "debian:latest", WslaContainerStateExited}});
+        }
+
         // Verify that trying to open a non existing container fails.
         {
             wil::com_ptr<IWSLAContainer> sameContainer;
@@ -1274,9 +1300,16 @@ class WSLATests
                 {{"exited-container", "debian:latest", WslaContainerStateExited},
                  {"test-unique-name", "debian:latest", WslaContainerStateExited}});
 
+            // Verify that calling Stop() on exited containers is a no-op and state remains as WslaContainerStateExited.
+            VERIFY_SUCCEEDED(container.Get().Stop(15, 1000));
+            VERIFY_ARE_EQUAL(container.State(), WslaContainerStateExited);
+
             // Verify that stopped containers can be deleted.
             VERIFY_SUCCEEDED(container.Get().Delete());
 
+            // Verify that stopping a deleted container returns ERROR_INVALID_STATE.
+            VERIFY_ARE_EQUAL(container.Get().Stop(15, 1000), HRESULT_FROM_WIN32(ERROR_INVALID_STATE));
+
             // Verify that deleted containers can't be deleted again.
             VERIFY_ARE_EQUAL(container.Get().Delete(), HRESULT_FROM_WIN32(ERROR_INVALID_STATE));