OSX:如何从IOUSBDeviceInterface或位置ID获取卷名(或BSD名)
题
我试图写与它的体积或BSD名称相关联的特定USB字符串描述符(USB大容量存储设备的)的应用程序。
因此,代码经过所有的连接的USB设备时,获取字符串描述符,并从它们中的一个中提取信息。我想获得这些USB设备的卷名。我无法找到合适的API来做到这一点。 我试图做的是:
DASessionRef session = DASessionCreate(kCFAllocatorDefault);
DADiskRef disk_ref = DADiskCreateFromIOMedia(kCFAllocatorDefault,
session,
usb_device_ref);
const char* name = DADiskGetBSDName(disk_ref);
但DADiskCreateFromIOMedia函数返回零,我假设我通过不符合该函数期待io_service_t兼容usb_device_ref。
所以,我怎么能得到一个USB设备的卷名?
我能使用位置ID这样做呢?
感谢阅读。 -L
FOO_Result result = FOO_SUCCESS;
mach_port_t master_port;
kern_return_t k_result;
io_iterator_t iterator = 0;
io_service_t usb_device_ref;
CFMutableDictionaryRef matching_dictionary = NULL;
// first create a master_port
if (FOO_FAILED(k_result = IOMasterPort(MACH_PORT_NULL, &master_port))) {
fprintf(stderr, "could not create master port, err = %d\n", k_result);
goto cleanup;
}
if ((matching_dictionary = IOServiceMatching(kIOUSBDeviceClassName)) == NULL)
{
fprintf(stderr, "could not create matching dictionary, err = %d\n", k_result);
goto cleanup;
}
if (FOO_FAILED(k_result = IOServiceGetMatchingServices(master_port, matching_dictionary, &iterator))) {
fprintf(stderr, "could not find any matching services, err = %d\n", k_result);
goto cleanup;
}
while (usb_device_ref = IOIteratorNext(iterator))
{
IOReturn err;
IOCFPlugInInterface **iodev; // requires <IOKit/IOCFPlugIn.h>
IOUSBDeviceInterface **dev;
SInt32 score;
err = IOCreatePlugInInterfaceForService(usb_device_ref, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &iodev, &score);
if (err || !iodev)
{
printf("dealWithDevice: unable to create plugin. ret = %08x, iodev = %p\n", err, iodev);
return;
}
err = (*iodev)->QueryInterface(iodev,
CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID),
(LPVOID*)&dev);
(*iodev)->Release(iodev); // done with this
FOO_String string_value;
UInt8 string_index = 0x1;
FOO_Result result = FOO_SUCCESS;
CFStringRef device_name_as_cf_string;
do {
if (FOO_SUCCEEDED(result = FOO_GetStringDescriptor(dev, string_index, 0, string_value))) {
printf("String at index %i is %s\n", string_index, string_value.GetChars());
// extract the command code if it is the FOO string
if (string_value.CompareN("FOO:", 4) == 0) {
FOO_Byte code = 0;
FOO_HexToByte(string_value.GetChars() + 4, code);
// Get other relevant information from the device
io_name_t device_name;
UInt32 location_id = 0;
// Get the USB device's name.
err = IORegistryEntryGetName(usb_device_ref, device_name);
device_name_as_cf_string = CFStringCreateWithCString(kCFAllocatorDefault, device_name,
kCFStringEncodingASCII);
err = (*dev)->GetLocationID(dev, &location_id);
// TODO: get volume or BSD name
// add the device to the list
break;
}
}
string_index++;
} while (FOO_SUCCEEDED(result));
err = (*dev)->USBDeviceClose(dev);
if (err)
{
printf("dealWithDevice: error closing device - %08x\n", err);
(*dev)->Release(dev);
return;
}
err = (*dev)->Release(dev);
if (err)
{
printf("dealWithDevice: error releasing device - %08x\n", err);
return;
}
IOObjectRelease(usb_device_ref); // no longer need this reference
}
解决方案
一旦你的io_service_t,您可以通过IORegistry递归找到BSD名称。你并不需要真正创建一个接口。
#import <IOKit/IOBSD.h>
CFStringRef bsdName = ( CFStringRef ) IORegistryEntrySearchCFProperty ( usbDevice,
kIOServicePlane,
CFSTR ( kIOBSDNameKey ),
kCFAllocatorDefault,
kIORegistryIterateRecursively );
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