修改设备驱动程序属性

3环：

//
//  main.c
//  DriverIterator
//

#include <CoreFoundation/CoreFoundation.h>
#include <IOKit/IOKitLib.h>


int main (int argc, const char * argv[])
{
	CFDictionaryRef		matchingDict = NULL;
	io_iterator_t		iter = 0;
	io_service_t		service = 0;
	kern_return_t		kr;
	
	matchingDict = IOServiceMatching("com_osxkernel_driver_IOKitTest");
	kr = IOServiceGetMatchingServices(kIOMasterPortDefault, matchingDict, &iter);
	if (kr != KERN_SUCCESS)
		return -1;
	
	//迭代所有匹配的对象
	while ((service = IOIteratorNext(iter)) != 0)
	{
		IORegistryEntrySetCFProperty(service, CFSTR("StopMessage"), CFSTR("The driver has stopped"));
		IOObjectRelease(service);
	}
	IOObjectRelease(iter);
	
	return 0;
}

0环： //IOKitTest.h

#include <IOKit/IOService.h>

class com_osxkernel_driver_IOKitTest : public IOService
{
	OSDeclareDefaultStructors(com_osxkernel_driver_IOKitTest)
	
public:	
	virtual bool	init (OSDictionary* dictionary = NULL);
	virtual void	free (void);
	
	virtual IOService*	probe (IOService* provider, SInt32* score);
	virtual bool	start (IOService* provider);
	virtual void	stop (IOService* provider);
	
	virtual IOReturn	setProperties (OSObject* properties);
};

//IOKitTest.cpp

#include "IOKitTest.h"
#include <IOKit/IOLib.h>

#define super IOService

OSDefineMetaClassAndStructors(com_osxkernel_driver_IOKitTest, IOService)


bool com_osxkernel_driver_IOKitTest::init (OSDictionary* dict)
{
	bool res = super::init(dict);
	IOLog("IOKitTest::init\n");
	return res;
}

void com_osxkernel_driver_IOKitTest::free (void)
{
	IOLog("IOKitTest::free\n");
	super::free();
}

IOService* com_osxkernel_driver_IOKitTest::probe (IOService* provider, SInt32* score)
{
	IOService *res = super::probe(provider, score);
	IOLog("IOKitTest::probe\n");
	return res;
}

bool com_osxkernel_driver_IOKitTest::start (IOService *provider)
{
	bool res = super::start(provider);
	IOLog("IOKitTest::start\n");
	return res;
}

void com_osxkernel_driver_IOKitTest::stop (IOService *provider)
{
	OSString*	stopMessage;
	
	//从驱动程序属性表读取可能自定义字符串并输出
	stopMessage = OSDynamicCast(OSString, getProperty("StopMessage"));
    IOLog("IOKitTest::stop\n");
	if (stopMessage)
		IOLog("%s\n", stopMessage->getCStringNoCopy());
	
	super::stop(provider);
}

IOReturn com_osxkernel_driver_IOKitTest::setProperties (OSObject* properties)
{
	OSDictionary*	propertyDict;
	
	//提供的属性对象应该是一个OSDictionary对象
	propertyDict = OSDynamicCast(OSDictionary, properties);
	if (propertyDict != NULL)
	{
		OSObject*		theValue;
		OSString*		theString;
		
		//从字典读取对应的StopMessage键值
		theValue = propertyDict->getObject("StopMessage");
		theString = OSDynamicCast(OSString, theValue);
		if (theString != NULL)
		{
			//将该值添加到驱动程序的属性列表
			setProperty("StopMessage", theString);
			return kIOReturnSuccess;
		}
	}
	
	return kIOReturnUnsupported;
}