Using IOSleep in socket filtering kernel extension - objective-c

Question

I'm developing a kernel extension which processes every socket is build on system and waits in user space to get confirmation from user to allow or deny that socket.
I'm using IOSleep to apply the wait i mentioned above but it gives this error when loading kernel extension.
"the following symbols are unresolved for this kext:
_IOSleep"
First of all , i want to know am i correct about using IOSleep to make waiting ?
If not , how should i apply desired waiting to cover time interval that i need to get user confirmation about allowing or rejecting a specific socket connection?
Thanks in advance for any useful response.

Answer 1

IOSleep is perfectly fine in a kernel extension. The error you see is because libraries are linked to kexts at load time, not compile time.
When you add functions to your code that require linking against new libraries, you must call kextlibs on the compiled binary in order to find out what you need to add to the plist file. This is explained in the Add Library Declarations section of the Generic Kernel Extension tutorial in the Mac Developer Library, but it's easy to forget to do this after the first time.
The basic steps are:
Build your kext
Run the command kextlibs -xml MyKext.kext in the Terminal
Replace the <key>OSBundleLibraries</key><dict>...</dict> part of your kext's Info.plist file with the printout from the above
Rebuild your kext
It should now link correctly when you load it with kextload.