Hi!
A few days ago I sent 2 patches for gdi32 to wine-patches that passed unnoticed. I would like if someone could give me some feedback on them.
Let me first give you some background about these patches. There is an application called "Compumap" that is a street map of some Argentine cities. It is rather popular here because some years ago it was distributed with a newspaper.
The program works quite well under Wine (although the installer still has some problems), but when you try to print a map it crashes.
A few weeks ago I had some free time and I decided to try to find out why it crashes. I run it through the Wine Debugger and also under a debugger in Windows XP.
The problem happened to be two API calls with incomplete/invalid parameters. Windows XP returned NULL or ignore the wrong data, while Wine crashes.
1) gdi32: Protect against short sized LOGPALETTE in CreatePalette. http://www.winehq.org/pipermail/wine-patches/2008-February/050354.html
This crash was caused by "CreatePalette(HDC, LOGPALETTE)" being called with a short allocated palette. Windows XP returned NULL in that case. I tried to reproduce that behavior by first checking the parameter with "IsBadReadPtr()" function.
2) gdi32: StartDocA support for legacy apps with incomplete DOCINFOA parameter. http://www.winehq.org/pipermail/wine-patches/2008-February/050357.html
This issue was a call to "StartDocA(HDC, DOCINFOA)" with structure DOCINFOA not completely initialized (there is garbage in the last 2 fields). I debugged this API and found that Windows XP ignored those fields when the data "seems to be invalid". I think that the last 2 fields were introduced in Win32 and some applications ported from Win16 "forget" to clear them. I simulated Windows XP behaviour by putting some safe checks on those fields.
With those 2 fixes, the application is able to print under Wine. Both patches are short and rather easy to review. I will appreciate if someone could give me some feedback on them.
Thanks ...
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Daniel Mario Vega