server: Fix for possible desktop variable being NULL when set_process_default_desktop is called

[Robert Shearman]

Alexandre Julliard wrote:

>Robert Shearman <rob at codeweavers.com> writes:
>
>  
>
>>ChangeLog:
>>The desktop variable could be NULL when set_process_default_desktop is
>>called, so check for this. (Found by Coverity).
>>    
>>
>
>I don't see how this could happen. Did I miss something?
>

See below.

>void connect_process_winstation( *struct* process *process, *struct* thread *parent )
>{
>    *struct* winstation *winstation = NULL;
>    *struct* desktop *desktop = NULL;
>    obj_handle_t handle;
>
>    //* check for an inherited winstation handle (don't ask...) *//
>    *if* ((handle = find_inherited_handle( process, &winstation_ops )))
>    {
>        winstation = (*struct* winstation *)get_handle_obj( process, handle, 0, &winstation_ops );
>    }
>    *else* *if* (parent && parent->process->winstation)
>    {
>        handle = duplicate_handle( parent->process, parent->process->winstation,
>                                   process, 0, 0, DUP_HANDLE_SAME_ACCESS );
>        winstation = (*struct* winstation *)get_handle_obj( process, handle, 0, &winstation_ops );
>    }
>    *if* (!winstation) *goto* done;
>    process->winstation = handle;
>  
>

Handle is non-NULL here.

>    *if* ((handle = find_inherited_handle( process, &desktop_ops )))
>    {
>        desktop = get_desktop_obj( process, handle, 0 );
>        *if* (!desktop || desktop->winstation != winstation) *goto* done;
>    }
>    *else* *if* (parent && parent->desktop)
>    {
>        desktop = get_desktop_obj( parent->process, parent->desktop, 0 );
>        *if* (!desktop || desktop->winstation != winstation) *goto* done;
>        handle = duplicate_handle( parent->process, parent->desktop,
>                                   process, 0, 0, DUP_HANDLE_SAME_ACCESS );
>    }
>  
>

If the process neither has desktop nor its parent has a desktop then 
handle will be non-NULL here, yet desktop will be NULL.

>    *if* (handle) set_process_default_desktop( process, desktop, handle );
>
>done:
>    *if* (desktop) release_object( desktop );
>    *if* (winstation) release_object( winstation );
>    clear_error();
>}
>  
>


-- 
Rob Shearman