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macoscocoakernel-extension

Detect if OS X kernel extension is loadable

I'm attempting to write an application that talks to a custom USB device. We have written a driver (kext) that is automatically loaded when the USB device is attached to the computer. It is installed into the appropriate location (/System/Library/Extensions & /Library/Extensions) during the installation process.

In my application (.app), I need to be able to confirm that this kext is installed and is loadable on the user's computer.

My initial thought was to use the "System" command and get the result of "kextstat | grep mykext". However, kextstat only shows the kernel extensions that are loaded. (It's possible the application can be launched before the user has attached the USB device).

The only other thing that I can think of is to use "kextfind | grep mykext" to determine if the kext exists, however, I don't know if it is loadable or not. (ie. it could exist, but someone messed with the plist file, and now the signature fails, so it won't ever be loaded)

I know that it's possible, because Apple's System Profiler is able to list all of the extensions, if they are loaded, and if they are loadable.
System Profiler

Solution

  • From the kextutil man page:

    kextutil prints diagnostic information about kexts by default, but some options cause certain tests to be skipped. To ensure that all tests are performed, use the -print-diagnostics (-t) option. The -print-diagnostics option is typically used with -no-load (-n) after a load failure to pinpoint a problem. It can be used with any other set of options, however.

    Note: when the -no-load (-n) option is used then sudo (root user) isn't required.