Signed-off-by: Derek Lesho <dereklesho52@Gmail.com>
---
 dlls/ntoskrnl.exe/ntoskrnl.c        | 18 ++++++++++++++++++
 dlls/ntoskrnl.exe/ntoskrnl.exe.spec |  2 +-
 dlls/ntoskrnl.exe/tests/driver.c    | 18 ++++++++++++++++++
 include/ddk/ntifs.h                 |  1 +
 4 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/dlls/ntoskrnl.exe/ntoskrnl.c b/dlls/ntoskrnl.exe/ntoskrnl.c
index 3789abda35..0ab150ea65 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.c
+++ b/dlls/ntoskrnl.exe/ntoskrnl.c
@@ -3233,6 +3233,24 @@ NTSTATUS WINAPI PsLookupProcessByProcessId(HANDLE processid, PEPROCESS *process)
 }


+/*****************************************************
+ *           PsLookupThreadByThreadId   (NTOSKRNL.EXE.@)
+ */
+NTSTATUS WINAPI PsLookupThreadByThreadId(HANDLE threadid, PETHREAD *thread)
+{
+    NTSTATUS status;
+    HANDLE hThread = OpenThread( THREAD_ALL_ACCESS, FALSE, HandleToUlong(threadid) );
+
+    if (!hThread)
+        return STATUS_INVALID_PARAMETER;
+
+    status = ObReferenceObjectByHandle( hThread, THREAD_ALL_ACCESS, PsThreadType, KernelMode, (void**)thread, NULL );
+
+    NtClose( hThread );
+    return status;
+}
+
+
 /*****************************************************
  *           IoSetThreadHardErrorMode  (NTOSKRNL.EXE.@)
  */
diff --git a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
index 141c8aa639..f965ff55ec 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
+++ b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
@@ -914,7 +914,7 @@
 @ stub PsJobType
 @ stdcall PsLookupProcessByProcessId(ptr ptr)
 @ stub PsLookupProcessThreadByCid
-@ stub PsLookupThreadByThreadId
+@ stdcall PsLookupThreadByThreadId(ptr ptr)
 @ extern PsProcessType
 @ stub PsReferenceImpersonationToken
 @ stub PsReferencePrimaryToken
diff --git a/dlls/ntoskrnl.exe/tests/driver.c b/dlls/ntoskrnl.exe/tests/driver.c
index c3839da3bf..4b846869fc 100644
--- a/dlls/ntoskrnl.exe/tests/driver.c
+++ b/dlls/ntoskrnl.exe/tests/driver.c
@@ -29,6 +29,7 @@
 #include "winternl.h"
 #include "winioctl.h"
 #include "ddk/ntddk.h"
+#include "ddk/ntifs.h"
 #include "ddk/wdm.h"

 #include "driver.h"
@@ -1167,6 +1168,22 @@ static void test_resource(void)
     ok(status == STATUS_SUCCESS, "got status %#x\n", status);
 }

+static void test_lookup_thread(void)
+{
+    NTSTATUS status;
+    PETHREAD thread = NULL;
+
+    status = PsLookupThreadByThreadId(PsGetCurrentThreadId(), &thread);
+    ok(!status, "PsLookupThreadByThreadId failed: %#x\n", status);
+    ok((PKTHREAD)thread == KeGetCurrentThread(), "thread != KeGetCurrentThread\n");
+
+    if (thread)
+        ObDereferenceObject(thread);
+
+    status = PsLookupThreadByThreadId(NULL, &thread);
+    ok(status == STATUS_INVALID_PARAMETER, "PsLookupThreadByThreadId returned %#x\n", status);
+}
+
 static NTSTATUS main_test(DEVICE_OBJECT *device, IRP *irp, IO_STACK_LOCATION *stack, ULONG_PTR *info)
 {
     ULONG length = stack->Parameters.DeviceIoControl.OutputBufferLength;
@@ -1210,6 +1227,7 @@ static NTSTATUS main_test(DEVICE_OBJECT *device, IRP *irp, IO_STACK_LOCATION *st
     test_lookaside_list();
     test_ob_reference(test_input->path);
     test_resource();
+    test_lookup_thread();

     /* print process report */
     if (winetest_debug)
diff --git a/include/ddk/ntifs.h b/include/ddk/ntifs.h
index abe357fbc9..9b57ae7ad7 100644
--- a/include/ddk/ntifs.h
+++ b/include/ddk/ntifs.h
@@ -131,6 +131,7 @@ typedef struct _FS_FILTER_CALLBACKS

 BOOLEAN WINAPI FsRtlIsNameInExpression(PUNICODE_STRING, PUNICODE_STRING, BOOLEAN, PWCH);
 NTSTATUS WINAPI ObQueryNameString(PVOID,POBJECT_NAME_INFORMATION,ULONG,PULONG);
+NTSTATUS WINAPI PsLookupThreadByThreadId(HANDLE,PETHREAD*);
 void WINAPI PsRevertToSelf(void);

 #endif
--
2.20.1