kernel32: Fix CancelIoEx return value.

In commit 27ecc6b ("ntdll: Fix iosb handling in NtCancelIoFile()"),
NtCancelIoFile(Ex) was updated to return its status rather than
unconditionally setting it in io_status->u.Status (though the write
was retained in the success case). As a result, in the error case,
the kernelbase wrappers now interpret unitialized memory as an error
code, since io_status->u.Status is never written.

Signed-off-by: Keno Fischer <keno@juliacomputing.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>

dlls/kernel32/tests/pipe.c

@@ -2941,6 +2941,7 @@ static void test_blocking_rw(HANDLE writer, HANDLE reader, DWORD buf_size, BOOL
     OVERLAPPED read_overlapped, read_overlapped2, write_overlapped, write_overlapped2;
     char buf[10000], read_buf[10000];
     HANDLE flush_thread;
+    BOOL res;
 
     memset(buf, 0xaa, sizeof(buf));
 
@@ -3074,6 +3075,17 @@ static void test_blocking_rw(HANDLE writer, HANDLE reader, DWORD buf_size, BOOL
     overlapped_write_sync(writer, buf, 1);
     test_overlapped_result(reader, &read_overlapped, 1, FALSE);
 
+    /* Test that canceling the same operation twice gives a sensible error */
+    SetLastError(0xdeadbeef);
+    overlapped_read_async(reader, read_buf, 1, &read_overlapped2);
+    res = pCancelIoEx(reader, &read_overlapped2);
+    ok(res, "CancelIoEx failed with error %d\n", GetLastError());
+    res = pCancelIoEx(reader, &read_overlapped2);
+    ok(!res, "CancelIOEx succeeded unexpectedly");
+    ok(GetLastError() == ERROR_NOT_FOUND,
+        "In CancelIoEx failure, expected ERROR_NOT_FOUND, got %d\n", GetLastError());
+    test_overlapped_failure(reader, &read_overlapped2, ERROR_OPERATION_ABORTED);
+
     /* make two async writes, cancel the first one and make sure that we read from the second one */
     overlapped_write_async(writer, buf, buf_size+2000, &write_overlapped);
     overlapped_write_async(writer, buf, 1, &write_overlapped2);

dlls/kernelbase/file.c

@@ -2872,8 +2872,7 @@ BOOL WINAPI DECLSPEC_HOTPATCH CancelIo( HANDLE handle )
 {
     IO_STATUS_BLOCK io;
 
-    NtCancelIoFile( handle, &io );
-    return set_ntstatus( io.u.Status );
+    return set_ntstatus( NtCancelIoFile( handle, &io ) );
 }
 
 
@@ -2884,8 +2883,7 @@ BOOL WINAPI DECLSPEC_HOTPATCH CancelIoEx( HANDLE handle, LPOVERLAPPED overlapped
 {
     IO_STATUS_BLOCK io;
 
-    NtCancelIoFileEx( handle, (PIO_STATUS_BLOCK)overlapped, &io );
-    return set_ntstatus( io.u.Status );
+    return set_ntstatus( NtCancelIoFileEx( handle, (PIO_STATUS_BLOCK)overlapped, &io ) );
 }