Path check in kdelibs/plasma/package.cpp ?

[Frank Wilson]

I've been trying out kde 4.2 beta 2 and I have an issue with the way
different wallpapers are loaded.

My problem is that I cannot change my wallpaper to one of the default
directory-packaged wallpapers that come with kde (n.b. single-image
wallpapers are fine!). When I click on the "Picture" drop down box none
of the directory-packaged wallpapers display. When I select
one of the directory-packaged wallpapers the background is set to a
plain colour background and not the wallpaper I asked for.

When I select a directory-packaged wallpaper or display the drop down
list I get messages such as the following:

> plasma(10713)/libplasma Plasma::Package::filePath:
>> "/System/Links/Shared/wallpapers/Vector_Sunset/contents/
>> screenshot.png" does not exist

and when I select a directory-packaged wallpaper I also get:

> QImage::scaled: Image is a null image

I am using GoboLinux, which does not use the FHS. So, on my distro
kde-libs is installed in /Programs/KDE-Libs/Current, kde-base-workspace
in /Programs/KDE-Base-Workspace/Current, etc. Everything is symlinked
under /System/Links/Executables, /System/Links/Shared, etc.

It seems that kde is looking for the wallpapers under 
/System/Links/Shared/wallpapers and it does not like symlinks such as,

/System/Links/Shared/wallpapers/Vector_Sunset

which points to

/Programs/KDE-Base-Workspace/4.1.85/Shared/wallpapers/Vector_Sunset

I know this because when I removed the symbolic link and replaced it 
with a physical copy of the wallpaper, everything worked once again.

I had a look at the code involved and it seems that you are doing
some sort of explicit checks for symbolic links in Package::filePath() 
in the file kdelibs/plasma/package.cpp .

Specifically, this check fails:

     if (canonicalized.startsWith(d->basePath)) { ...

I added a bit more debug output, namely:

     if (QFile::exists(path)) {
         // ensure that we don't return files outside of our base path
         // due to symlink or ../ games
         QDir dir(path);
         QString canonicalized = dir.canonicalPath() + QDir::separator();
		/*** Extra Debug output ***/
                 kDebug() << "canonical path is: " << canonicalized;
                 kDebug() << "base path is: " << d->basePath;
		/**************************/
         if (canonicalized.startsWith(d->basePath)) {
             return path;
         }
     }

Which gave me the following output when I tried to select a
directory-packaged wallpaper:

plasma(10713)/libplasma Plasma::Package::filePath: canonical path is: 
"/Programs/KDE-Base-Workspace/4.1.85/Shared/wallpapers/Vector_Sunset/contents/screenshot.png/"
plasma(10713)/libplasma Plasma::Package::filePath: base path is: 
"/System/Links/Shared/wallpapers/Vector_Sunset/"
plasma(10713)/libplasma Plasma::Package::filePath: 
"/System/Links/Shared/wallpapers/Vector_Sunset/contents/screenshot.png" 
does not exist

I have two questions about this. Firstly, is there some cmake option 
that would allow this check to pass? Secondly, what is the purpose of 
this check?

Thanks,

Frank Wilson