获取有关 USB 设备（OSX、C++）的信息，IOCreatePlugInInterfaceForService 失败

Question

我正在尝试遍历 USB 设备以查找 USB 大容量存储并获取 PID 和 VID。为此，我试图在 IOUSBDeviceInterface 上获得参考，但 IOCreatePlugInInterfaceForService 失败并出现奇怪的错误代码：0x2C7 - “不支持的功能”。有人可以告诉我，我做错了什么吗？这是我的代码：

#include <iostream>
#include <IOKit/IOkitLib.h>
#include <IOKit/usb/IOUSBLib.h>
#include <IOKit/IOCFPlugIn.h>
#include <IOKit/usb/USBSpec.h>
#include <CoreFoundation/CoreFoundation.h>

int main(int argc, const char * argv[]) 
{
CFMutableDictionaryRef matchingDictionary = NULL;
io_iterator_t foundIterator = 0;
io_service_t usbDevice;
matchingDictionary = IOServiceMatching(kIOUSBDeviceClassName);

IOServiceGetMatchingServices(kIOMasterPortDefault, matchingDictionary, &foundIterator);

for(usbDevice = IOIteratorNext(foundIterator); usbDevice; usbDevice = IOIteratorNext(foundIterator))
{
    IOCFPlugInInterface** plugin = NULL;
    SInt32 theScore=0;
    IOReturn err;
    err = IOCreatePlugInInterfaceForService(usbDevice, kIOUSBInterfaceUserClientTypeID, kIOCFPlugInInterfaceID, &plugin, &theScore);
    if (err!= 0){
        //for all the devices (including Mass Storage), I get the same 
        //error: system 0x38 (IOKit), code: 0x2C7 (unsupported function) 
        std::cout<<"error, error code: "<<err_get_code(err) <<std::endl;
    }
    else if (plugin && *plugin)
    {
        //never happens
        IOUSBDeviceInterface** usbInterface = NULL;
        (*plugin)->QueryInterface(plugin, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID),(LPVOID*)&usbInterface);
        (*plugin)->Release(plugin);
        if (usbInterface && *usbInterface)
        {
             //other actions with usbInterface
        }       

    }

}
IOObjectRelease(foundIterator);
return 0;
}

Answer 1

您正在匹配IOUSBDevice 服务，但尝试连接IOUSBInterfaceUserClient。如果要连接到IOUSBDevice 服务，用户客户端类型必须是kIOUSBDeviceUserClientTypeID。如果你想要一个IOUSBInterfaceUserClient，你需要匹配IOUSBInterface服务。