Question

I want to create a bundle from an arbitrary bundle identifier
e.g. com.apple.iokit.IOStorageFamily

It’s not an unreasonable thing to do as bundle IDs are supposed
to be unique, however the obvious code does not work:

NSString* bID = @"com.apple.iokit.IOStorageFamily";
NSBundle* bundle = [NSBundle bundleWithIdentifier:bID];

This code only works for bundles you’ve already loaded
(hello, chicken and egg problem), and in fact, you have
to know a little more than you’d like about the the identifier
before you can do anything. For the above style of ID
I grep out the final component and tranform it into
/System/Library/Extensions/IOStorageFamily.kext
which I then load by path.

Is this the state of the art or is there a more general way?

Answer 1

Just recently Andrew Myrick answered a similar question on the darwin-dev mailing list:

KextManagerCreateURLForBundleIdentifier()
in <IOKit/kext/KextManager.h> may be
of use, though I believe it only works
for kexts that are either 1) loaded,
or 2) in /S/L/E/. Here is the Snow
Leopard headerdoc:

/*!
 * @function KextManagerCreateURLForBundleIdentifier
 * @abstract Create a URL locating a kext with a given bundle identifier.
 *
 * @param    allocator
 *           The allocator to use to allocate memory for the new object.
 *           Pass <code>NULL</code> or <code>kCFAllocatorDefault</code>
 *           to use the current default allocator.
 * @param    kextIdentifier
 *           The bundle identifier to look up.
 *
 * @result
 * A CFURLRef locating a kext with the requested bundle identifier.
 * Returns <code>NULL</code> if the kext cannot be found, or on error.
 *
 * @discussion
 * Kexts are looked up first by whether they are loaded, second by version.
 * Specifically, if <code>kextIdentifier</code> identifies a kext
 * that is currently loaded,
 * the returned URL will locate that kext if it's still present on disk.
 * If the requested kext is not loaded,
 * or if its bundle is not at the location it was originally loaded from,
 * the returned URL will locate the latest version of the desired kext,
 * if one can be found within the system extensions folder.
 * If no version of the kext can be found, <code>NULL</code> is returned.
 */
CFURLRef KextManagerCreateURLForBundleIdentifier(
    CFAllocatorRef allocator,
    CFStringRef    kextIdentifier);

Note that prior to Snow Leopard, it
may only work for kexts in /S/L/E; the
API existed, but there was no
headerdoc describing its behavior.

For me this worked really well on Mac OS X 10.5.