对于我来说，通过USB迭代以下方式在OSX工作：
void scanUsbMassStorage()
{
CFMutableDictionaryRef matchingDictionary = IOServiceMatching(kIOUSBInterfaceClassName);
//now specify class and subclass to iterate only through USB mass storage devices:
CFNumberRef cfValue;
SInt32 deviceClassNum = kUSBMassStorageInterfaceClass;
cfValue = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &deviceClassNum);
CFDictionaryAddValue(matchingDictionary, CFSTR(kUSBInterfaceClass), cfValue);
CFRelease(cfValue);
SInt32 deviceSubClassNum = kUSBMassStorageSCSISubClass;
cfValue = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &deviceSubClassNum);
CFDictionaryAddValue(matchingDictionary, CFSTR(kUSBInterfaceSubClass), cfValue);
CFRelease(cfValue);
//NOTE: if you will specify only device class and will not specify subclass, it will return an empty iterator,
//and I don't know how to say that we need any subclass.
//BUT: all the devices I've check had kUSBMassStorageSCSISubClass
io_iterator_t foundIterator = 0;
io_service_t usbInterface;
IOServiceGetMatchingServices(kIOMasterPortDefault, matchingDictionary, &foundIterator);
//iterate through USB mass storage devices
for(usbInterface = IOIteratorNext(foundIterator); usbInterface; usbInterface = IOIteratorNext(foundIterator))
{
CFTypeRef bsdName = IORegistryEntrySearchCFProperty(usbInterface,
kIOServicePlane,
CFSTR(kIOBSDNameKey),
kCFAllocatorDefault,
kIORegistryIterateRecursively);
CFTypeRef serial = IORegistryEntrySearchCFProperty(usbInterface,
kIOServicePlane,
CFSTR(kUsbSerialPropertyName),
kCFAllocatorDefault,
kIORegistryIterateRecursively|kIORegistryIterateParents);
CFTypeRef pid = IORegistryEntrySearchCFProperty(usbInterface,
kIOServicePlane,
CFSTR(kUsbPidPropertyName),
kCFAllocatorDefault,
kIORegistryIterateRecursively|kIORegistryIterateParents);
CFTypeRef vid = IORegistryEntrySearchCFProperty(usbInterface,
kIOServicePlane,
CFSTR(kUsbVidPropertyName),
kCFAllocatorDefault,
kIORegistryIterateRecursively|kIORegistryIterateParents);
//now we can perform checks and casts from CFTypeRef like this:
std::string filePathStr;
std::string serialStr;
uint16_t pidInt;
uint16_t vidInt;
//getMountPathByBSDName - see below
bool stillOk = getMountPathByBSDName(bsdName, filePath);
if (stillOk)
{
stillOk = CFTypeRef2AsciiString(serial, serialStr);
}
if (stillOk)
{
stillOk = CFTypeRef2uint16(pid, pidInt);
}
if (stillOk)
{
stillOk = CFTypeRef2uint16(vid, vidInt);
}
if (stillOK)
{
//can do something with the values here
}
}
充分利用BSD名称安装路径，虽然是意外棘手对我而言，如果有人知道更好的方法，请分享它。这是我的方法。有大量的代码，但至少这个工作在几个不同版本的OSX：
bool getMountPathByBSDName(CFTypeRef bsdName, std::string& dest)
{
std::list<std::string> bsdNames;
//for getChildBsdNames - see below =)
getChildBsdNames(bsdName, bsdNames);
DASessionRef session = DASessionCreate(kCFAllocatorDefault);
if (!session)
{
return false;
}
for (const auto& bsdNameStr : bsdNames)
{
DADiskRef disk = DADiskCreateFromBSDName(kCFAllocatorDefault, session, bsdNameStr.c_str());
if (disk)
{
CFDictionaryRef diskInfo = DADiskCopyDescription(disk);
if (diskInfo)
{
char buf[1024];
CFURLRef fspath = (CFURLRef)CFDictionaryGetValue(diskInfo, kDADiskDescriptionVolumePathKey);
if (CFURLGetFileSystemRepresentation(fspath, false, (UInt8 *)buf, 1024))
{
//for now, return the first found partition
dest = std::string(buf);
return true;
}
}
}
}
return false;
}
最后 - getChildBsdNames功能：
void getChildBsdNames(CFTypeRef bsdName, std::list<std::string>& tgtList)
{
std::string bsdNameStr;
if(!CFTypeRef2AsciiString(bsdName, bsdNameStr))
{
return;
}
CFDictionaryRef matchingDictionary = IOBSDNameMatching(kIOMasterPortDefault, 0, bsdNameStr.c_str());
io_iterator_t it;
IOServiceGetMatchingServices(kIOMasterPortDefault, matchingDictionary, &it);
io_object_t service;
while ((service = IOIteratorNext(it)))
{
io_iterator_t children;
io_registry_entry_t child;
IORegistryEntryGetChildIterator(service, kIOServicePlane, &children);
while((child = IOIteratorNext(children)))
{
CFTypeRef bsdNameChild = IORegistryEntrySearchCFProperty(child,
kIOServicePlane,
CFSTR (kIOBSDNameKey),
kCFAllocatorDefault,
kIORegistryIterateRecursively);
std::string bsdNameChildStr;
if (CFTypeRef2AsciiString(bsdNameChild, bsdNameChildStr))
{
tgtList.push_back(bsdNameChildStr);
}
}
}
/**
* The device could get name 'disk1s1, or just 'disk1'. In first case, the original bsd name would be
* 'disk1', and the child bsd name would be 'disk1s1'. In second case, there would be no child bsd names,
* but the original one is valid for further work (obtaining various properties).
*/
if (tgtList.empty())
{
tgtList.push_back(bsdNameStr);
}
}
附：有一个基于事件的机制，但由于某些原因，这不是一个解决方案。我选择了轮询，但修改此代码以使其基于事件并不难。但是要小心，甚至可能会早于设备的安装时间。