cppcheck sept 18 redux

[Ben Klein]

2009/9/22 Mike Kaplinskiy <mike.kaplinskiy at gmail.com>:
> On Tue, Sep 22, 2009 at 1:09 AM, Vitaliy Margolen
> <wine-devel at kievinfo.com> wrote:
>>> [/home/cahrendt/wine-git/dlls/wineps.drv/init.c:270]: (error) Possible
>>> null pointer dereference: dmW - otherwise it is redundant to check if
>>> dmW is null at line 272
>>
>> This is a real bug and should be fixed:
>>>     ptrdiff_t off_formname = (const char *)dmW->dmFormName - (const char *)dmW;
>> Does indeed dereference dmW to get the value of dmFormName.
>
> It actually doesn't, it's a tricky case where dmW->dwFormName ==
> &dmW->dwFormName, because dwFormName is an array allocated as part of
> the struct. I made that mistake too the previous cppcheck round.

I thought I'd covered this before. It's complaining about dmW not
being validated before dmW->dmFormName (which de-references dmW to get
at its dmFormName member). In current code, it's not a problem because
dmW is validated before it's run in both cases (lines 369 and 403). It
is right about the redundant test NULL check on 272 though; if dmW is
NULL, the function will segfault.