On Tue, Sep 22, 2009 at 3:06 AM, Ben Klein shacklein@gmail.com wrote:
2009/9/22 Mike Kaplinskiy mike.kaplinskiy@gmail.com:
On Tue, Sep 22, 2009 at 1:09 AM, Vitaliy Margolen wine-devel@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.
It actually does not dereference anything. Try passing null into the function - it will work just fine. This is a special case because the array isn't dynamically allocated but is part of the struct, which means that dmW->dmFormName == (dmW+__offset of dmFormName) and not *(dmW+__offset of dmFormName). You can try writing a test program yourself - it will run just fine.
Mike.