Merge the WSL Container SDK DLL project into the main feature branch by 1wizkid · Pull Request #14172 · microsoft/WSL

1wizkid · 2026-02-06T20:42:49Z

this adds a new project src/windows/wslcsdk and the necessary .h and cpp files to build the WSLCSDK.DLL.

Copilot

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benhillis · 2026-02-06T21:51:57Z

I've updated the target branch.

Copilot

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 24 comments.

Copilot · 2026-02-06T23:05:52Z

src/windows/WslcSDK/wslcsdk.h

+#include <windows.h>
+#include <stdint.h>
+#include <winsock2.h>


Including <windows.h> before <winsock2.h> can cause Winsock header conflicts for consumers of this public SDK header (unless they happen to define _WINSOCKAPI_ first). Consider including <winsock2.h> before <windows.h> (or define _WINSOCKAPI_/use a lean include strategy) to make the header safe to include standalone.

Suggested change

#include <windows.h>

#include <stdint.h>

#include <winsock2.h>

#include <winsock2.h>

#include <windows.h>

#include <stdint.h>

Copilot · 2026-02-06T23:05:52Z

src/windows/WslcSDK/wslcsdk.h

+STDAPI WslcSessionSettingsVHD(_In_ WslcSessionSettings sessionSettings,
+                                 _In_ WSLC_VHD_REQUIREMENTS vhdRequirements);
+
+STDAPI WslcSessionSettingsTimeout(_In_ WslcSessionSettings sessionSettings,
+                                  uint32_t timeoutMS);
+
+
+STDAPI WslcSessionSettingsFlags(_In_ WslcSessionSettings sessionSettings,
+                                   _In_ WSLC_SESSION_FLAGS flags);
+
+// Pass in Null for callback to clear the termination callback
+STDAPI WslcSessionSettingsTerminateCallback(_In_ WslcSessionSettings sessionSettings,


The optional “settings” mutator APIs take the settings structs by value (e.g., WslcSessionSettingsTimeout(_In_ WslcSessionSettings sessionSettings, ...)). Since WslcSessionSettings/WslcContainerSettings/WslcProcessSettings are opaque byte blobs, passing by value means changes cannot propagate back to the caller, making these functions ineffective. These should take an _Inout_ pointer to the settings (and similarly for the container/process settings mutators).

Suggested change

STDAPI WslcSessionSettingsVHD(_In_ WslcSessionSettings sessionSettings,

_In_ WSLC_VHD_REQUIREMENTS vhdRequirements);

STDAPI WslcSessionSettingsTimeout(_In_ WslcSessionSettings sessionSettings,

uint32_t timeoutMS);

STDAPI WslcSessionSettingsFlags(_In_ WslcSessionSettings sessionSettings,

_In_ WSLC_SESSION_FLAGS flags);

// Pass in Null for callback to clear the termination callback

STDAPI WslcSessionSettingsTerminateCallback(_In_ WslcSessionSettings sessionSettings,

STDAPI WslcSessionSettingsVHD(_Inout_ WslcSessionSettings* sessionSettings,

_In_ WSLC_VHD_REQUIREMENTS vhdRequirements);

STDAPI WslcSessionSettingsTimeout(_Inout_ WslcSessionSettings* sessionSettings,

uint32_t timeoutMS);

STDAPI WslcSessionSettingsFlags(_Inout_ WslcSessionSettings* sessionSettings,

_In_ WSLC_SESSION_FLAGS flags);

// Pass in Null for callback to clear the termination callback

STDAPI WslcSessionSettingsTerminateCallback(_Inout_ WslcSessionSettings* sessionSettings,

Copilot · 2026-02-06T23:05:52Z

src/windows/WslcSDK/wslcsdk.h

+STDAPI WslcSessionInitSettings(_In_ PCWSTR storagePath,
+                               _In_ uint32_t cpuCount,
+                               _In_ uint64_t memoryMb,
+                               _In_ WslcSessionSettings* sessionSettings);


WslcSessionInitSettings writes to sessionSettings, but it is annotated as _In_. This should be an _Out_/_Inout_ annotation (and ideally a size-aware annotation) to match the function’s behavior and avoid incorrect static analysis.

Suggested change

_In_ WslcSessionSettings* sessionSettings);

_Out_ WslcSessionSettings* sessionSettings);

Copilot · 2026-02-06T23:05:53Z

src/windows/WslcSDK/wslcsdk.h

+//PROCESS MANAGEMENT
+
+STDAPI WslcProcessGetPid(_In_ WslcProcess process,
+                         _Out_ const UINT32* pid);


WslcProcessGetPid declares the out parameter as const UINT32*, which prevents the function from writing the PID. This should be a non-const output pointer (e.g., UINT32*) to match the intent of an out parameter.

Suggested change

_Out_ const UINT32* pid);

_Out_ UINT32* pid);

Copilot · 2026-02-06T23:05:53Z

src/windows/WslcSDK/wslcsdk.h

+typedef struct WLSC_PULL_IMAGE_OPTIONS
+{
+    _In_z_ PCSTR uri; // e.g. "my.registry.io/hello-world:latest" or just "hello-world:latest" which will default to docker
+    _In_opt_ WslcContainerImageProgressCallback progressCallback;
+    _In_opt_ PVOID progressCallbackContext;
+    _In_opt_ WSLC_REGISTRY_AUTHENTICATION_INFORMATION authInfo;
+} WLSC_PULL_IMAGE_OPTIONS;
+
+
+STDAPI WslcSessionImagePull(_In_ WslcSession session,
+                            _In_ const WLSC_PULL_IMAGE_OPTIONS* options,


In WLSC_PULL_IMAGE_OPTIONS, the type name prefix is WLSC_... while the rest of the API uses WSLC_..., which looks inconsistent/typo-prone for a public SDK. Also authInfo is marked _In_opt_ but is a by-value struct (cannot be optional); consider making it a pointer or adding an explicit hasAuthInfo flag.

Suggested change

typedef struct WLSC_PULL_IMAGE_OPTIONS

{

_In_z_ PCSTR uri; // e.g. "my.registry.io/hello-world:latest" or just "hello-world:latest" which will default to docker

_In_opt_ WslcContainerImageProgressCallback progressCallback;

_In_opt_ PVOID progressCallbackContext;

_In_opt_ WSLC_REGISTRY_AUTHENTICATION_INFORMATION authInfo;

} WLSC_PULL_IMAGE_OPTIONS;

STDAPI WslcSessionImagePull(_In_ WslcSession session,

_In_ const WLSC_PULL_IMAGE_OPTIONS* options,

typedef struct WSLC_PULL_IMAGE_OPTIONS

{

_In_z_ PCSTR uri; // e.g. "my.registry.io/hello-world:latest" or just "hello-world:latest" which will default to docker

_In_opt_ WslcContainerImageProgressCallback progressCallback;

_In_opt_ PVOID progressCallbackContext;

_In_opt_ const WSLC_REGISTRY_AUTHENTICATION_INFORMATION* authInfo;

} WSLC_PULL_IMAGE_OPTIONS;

STDAPI WslcSessionImagePull(_In_ WslcSession session,

_In_ const WSLC_PULL_IMAGE_OPTIONS* options,

Copilot · 2026-02-06T23:05:56Z

src/windows/WslcSDK/wslcsdk.h

+    // if you want to override the default binding address
+    _In_opt_ struct sockaddr_storage windowsAddress; // accepts ipv4/6


windowsAddress is declared as a by-value sockaddr_storage but annotated _In_opt_ and described as optional. A non-pointer field cannot be null/optional. Consider changing this to a pointer (with an explicit length/family) or add an explicit flag indicating whether the address is present, and update the SAL accordingly.

Suggested change

// if you want to override the default binding address

_In_opt_ struct sockaddr_storage windowsAddress; // accepts ipv4/6

// Optional override for the default binding address. If NULL, the default

// address will be used. The buffer must point to a valid sockaddr (IPv4 or

// IPv6) of length windowsAddressLength bytes.

_In_reads_bytes_opt_(windowsAddressLength) const struct sockaddr* windowsAddress;

_In_ INT windowsAddressLength;

Copilot · 2026-02-06T23:05:57Z

src/windows/WslcSDK/wslcsdk.h

+// Pass in Null for stdIOCallback to clear the callback for the given handle
+STDAPI WslcProcessSettingsIoCallback(_In_ WslcProcessSettings processSettings,
+                                     _In_ WSLC_PROCESS_IO_HANDLE ioHandle,
+                                     _In_ WslcStdIOCallback stdIOCallback);


WslcProcessSettingsIoCallback documents passing NULL to clear the callback, but the parameter is annotated _In_ (non-optional). Mark the callback parameter as optional and ensure the implementation handles a null callback consistently.

Suggested change

_In_ WslcStdIOCallback stdIOCallback);

_In_opt_ WslcStdIOCallback stdIOCallback);

Copilot · 2026-02-06T23:05:57Z

src/windows/WslcSDK/wslcsdk.h

+                                        _In_ const WSLC_CONTAINER_PORT_MAPPING* portMappings);
+
+                              // Add the container volume to the volumes array
+STDAPI WslcContainerSettingsVolume(_In_ WslcContainerSettings containerSettings, _In_ const WSLC_CONTAINER_VOLUME* volumes);
+
+
+


WslcContainerSettingsPortMapping/WslcContainerSettingsVolume accept a pointer to mappings/volumes but provide no count/length and no documented terminator convention. Since the internal options struct tracks portsCount/volumesCount, the public API needs a way to specify the number of entries (or clearly document a sentinel-terminated array) to avoid undefined reads.

Suggested change

_In_ const WSLC_CONTAINER_PORT_MAPPING* portMappings);

// Add the container volume to the volumes array

STDAPI WslcContainerSettingsVolume(_In_ WslcContainerSettings containerSettings, _In_ const WSLC_CONTAINER_VOLUME* volumes);

_In_reads_(portMappingsCount) const WSLC_CONTAINER_PORT_MAPPING* portMappings,

_In_ UINT32 portMappingsCount);

// Add the container volume to the volumes array

STDAPI WslcContainerSettingsVolume(_In_ WslcContainerSettings containerSettings,

_In_reads_(volumesCount) const WSLC_CONTAINER_VOLUME* volumes,

_In_ UINT32 volumesCount);

Copilot · 2026-02-06T23:05:57Z

src/windows/WslcSDK/wslcsdk.cpp

+STDAPI WslcSessionSettingsDisplayName(_In_ WslcSessionSettings sessionSettings,
+                                      _In_ PCWSTR displayName)
+{
+    UNREFERENCED_PARAMETER(displayName);
+    UNREFERENCED_PARAMETER(sessionSettings);
+    return E_NOTIMPL;


WslcSessionSettingsDisplayName is exported in the .def file, but it isn’t declared in wslcsdk.h. Because of that, this definition will be emitted with C++ name mangling (no prior extern "C" declaration), and the .def export WslcSessionSettingsDisplayName will fail to link. Add the declaration under EXTERN_C_START in wslcsdk.h (or wrap this definition in EXTERN_C_START/END).

Copilot · 2026-02-06T23:05:57Z

src/windows/WslcSDK/cmakelists.txt

+set(SOURCES wslcsdk.cpp)
+set(HEADERS
+    wslcsdk.h
+    wslcsdkprivate.h
+)
+
+add_library(wslcsdk SHARED ${SOURCES} ${HEADERS} wslcsdk.def)
+set_target_properties(wslcsdk PROPERTIES EXCLUDE_FROM_ALL FALSE)
+add_dependencies(wslcsdk wslaserviceidl)
+target_link_libraries(wslcsdk ${COMMON_LINK_LIBRARIES} legacy_stdio_definitions common)
+target_precompile_headers(wslcsdk REUSE_FROM common)
+set_target_properties(wslcsdk PROPERTIES FOLDER windows)


This file is named cmakelists.txt, but CMake only auto-loads CMakeLists.txt in an add_subdirectory() directory. As-is, CMake will fail to configure this target unless the file is renamed to CMakeLists.txt (matching exact casing).

OneBlue

Thank you for doing this. Added a couple comments, most of the copilot comments seem to be accurate

OneBlue · 2026-02-06T23:35:56Z

src/windows/WslcSDK/wslcsdk.cpp

+    UNREFERENCED_PARAMETER(session);
+    return E_NOTIMPL;
+}
+STDAPI WslcContainerSettingsNetworkingMode(_In_ WslcContainerSettings containerSettings,


nit: I'd rename to WslcContainerSettingsSetNetworkingMode (same for below method) to follow the get / set naming

OneBlue · 2026-02-06T23:37:35Z

src/windows/WslcSDK/wslcsdk.cpp

+    return E_NOTIMPL;
+}
+STDAPI WslcContainerSettingsHostName(_In_ WslcContainerSettings containerSettings,
+                                     _In_ const PCSTR hostName)


nit: const is not needed here (already in PCSTR)`

Also I recommend using the long pointer version (LPCSTR) since that's what modern Windows APIs do

OneBlue · 2026-02-06T23:40:45Z

src/windows/WslcSDK/wslcsdk.cpp

+
+
+// SESSION DEFINITIONS
+STDAPI WslcSessionInitSettings(_In_ PCWSTR storagePath,


This method can't fail, since I recommend returning the sessions by copy to simplify things. This also remove the need for the "release" method for settings

OneBlue · 2026-02-06T23:41:36Z

src/windows/WslcSDK/wslcsdk.cpp

+    UNREFERENCED_PARAMETER(containerSettings);
+    return E_NOTIMPL;
+}
+STDAPI WslcContainerSettingsRuntimeName(_In_ WslcContainerSettings containerSettings,


I'd just use WslcContainerSettingsSetName (runtime is implied)

OneBlue · 2026-02-06T23:41:58Z

src/windows/WslcSDK/wslcsdk.cpp

+    return E_NOTIMPL;
+}
+
+STDAPI WslcContainerExecProcess(_In_ WslcContainer container,


I recommend just WslcContainerExec here

OneBlue · 2026-02-07T01:29:18Z

src/windows/WslcSDK/wslcsdk.h

+    WSLA_VhdTypeFixed,       // Fully allocated VHDX
+} WSLC_VhdType;
+
+typedef struct WSLC_VHD_REQUIREMENTS


I recommend using the same casing for all enum and structures (WSLCVhdRequirements)

Same for below enums

OneBlue · 2026-02-07T01:31:56Z

src/windows/WslcSDK/wslcsdk.h

+
+typedef struct WSLC_CONTAINER_PORT_MAPPING
+{
+    _In_ UINT16 windowsPort;          // Port on Windows host


Let's use uint16_t to match the rest of the API

OneBlue · 2026-02-07T01:35:10Z

src/windows/WslcSDK/wslcsdk.h

+typedef __callback VOID(CALLBACK WslcStdIOCallback)(_In_reads_bytes_(dataSize) const BYTE* data, _In_ UINT32 dataSize, _In_opt_ PVOID context);
+typedef enum WSLC_PROCESS_IO_HANDLE
+{
+    stdIn = 0,


This will conflicts with predefined std handles. I recommend prefixing the enum values with the enum type name (for all enums)

OneBlue · 2026-02-07T01:36:20Z

src/windows/WslcSDK/WslcsdkPrivate.h

+//#include <wil/result.h>   // error handling
+
+// SESSION DEFINITIONS
+typedef struct WSLC_SESSION_OPTIONS_INTERNAL


Let's make this a C++ header (no need for typedef struct)

OneBlue · 2026-02-07T01:36:55Z

src/windows/WslcSDK/WslcsdkPrivate.h

+    PVOID terminationCallbackContext;
+} WSLC_SESSION_OPTIONS_INTERNAL;
+
+typedef char WSLC_SESSION_OPTIONS_INTERNAL_SIZE_ASSERT[sizeof(WSLC_SESSION_OPTIONS_INTERNAL)];//size = 80


I recommend static_assert instead of this

richfr added 3 commits February 6, 2026 12:28

add the WSL Container SDK API DLL wslcsdk.dll

6c1746b

Add internal sdk header file

5076336

update primary cmakelists file with wslc sdk build

6802d4f

1wizkid requested a review from a team as a code owner February 6, 2026 20:42

1wizkid requested review from Brian-Perkins, OneBlue, benhillis, Copilot and craigloewen-msft February 6, 2026 20:42

Copilot AI reviewed Feb 6, 2026

View reviewed changes

benhillis changed the base branch from master to feature/wsl-for-apps February 6, 2026 21:51

benhillis requested a review from a team as a code owner February 6, 2026 21:51

benhillis requested review from Copilot and removed request for a team, Brian-Perkins and craigloewen-msft February 6, 2026 22:58

Copilot started reviewing on behalf of benhillis February 6, 2026 22:58 View session

Copilot AI reviewed Feb 6, 2026

View reviewed changes

OneBlue requested changes Feb 7, 2026

View reviewed changes

	_In_ WslcSessionSettings* sessionSettings);
	_Out_ WslcSessionSettings* sessionSettings);

		// if you want to override the default binding address
		_In_opt_ struct sockaddr_storage windowsAddress; // accepts ipv4/6

-    // if you want to override the default binding address
-    _In_opt_ struct sockaddr_storage windowsAddress; // accepts ipv4/6
+    // Optional override for the default binding address. If NULL, the default
+    // address will be used. The buffer must point to a valid sockaddr (IPv4 or
+    // IPv6) of length windowsAddressLength bytes.
+    _In_reads_bytes_opt_(windowsAddressLength) const struct sockaddr* windowsAddress;
+    _In_ INT windowsAddressLength;

	_In_ WslcStdIOCallback stdIOCallback);
	_In_opt_ WslcStdIOCallback stdIOCallback);



		// SESSION DEFINITIONS
		STDAPI WslcSessionInitSettings(_In_ PCWSTR storagePath,

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