Elevated Processes

Objective-c is an insecure language. Although the feature is being deprecated (I believe starting with Snow Leopard), a user may override a program's code.

An application that needs to perform a restricted action can prompt the user for Administrator password using the Security framework. However, for security reasons, the best methodology is to have a helper application, and launch it using the authorization obtained. This raises issues of setting +s on the helper tool and interprocess communication. Allegedly, all of these are very straightforward, but the Apple-provided BetterAuthorizationSample project is written in somewhat arcane C (there are goto statements!), and I find it very difficult to understand what's going on.

I would appreciate assistance, especially in the form of a non-Apple tutorial or documentation, indicating how to set up communication with an executable that is a secondary target in the same xcodeproj.

EDIT: Have now gotten helper application to launch. There was a typo in the filepath I passed to AEWP.

FSGetCatalogInfoBulk

I use this call to iterate over directory contents with fewer system calls. Sometimes, I delete files, and I need to open the iterator with kFSIterateDelete. The implementation is such that kFSIterateFlat was supposed to be able to permit such a delete-file operation, but does not in fact.
While testing the code, we commented out the actual delete, and found that the last n files in the directory were improperly processed. When we commented the delete back in, everything was cleared up.
The moral here is clear: When you open an FSIterator with the kFSIterateDelete flag, make sure to delete the files!

core foundation file manager

It's fun to reduce one problem to an already-solved problem.
I was working to remove all uses of the NSFileManager and replace them with faster CF file manager calls. I have one last function to fix, and even that is done (sans debugging) except that it relies on being able to determine if a file exists at a path held in a CFStringRef. I have a function

bool MyClass::fileExistsAtPath(NSString *filePath)
{
  return [[NSFileManager defaultManager] fileExistsAtPath:filePath];
}

but I want it to be

bool MyClass::fileExistsAtPath(CFStringRef path)
{
  return ???;
}

I have been searching the documentation, and I thought I could use a CFURL for this, but so far, I don't see any API that will tell me whether the url is valid.