Enumerate removable drives on Linux and macOS - c++

Question

On Windows I am able to enumerate removable drives using FindFirstVolume, FindNextVolume, GetVolumePathNamesForVolumeName and the GetDriveType functions. How can I achieve this on Linux and macOS?

Answer 1

On macOS you need to work with IOKit: https://developer.apple.com/documentation/iokit
It can looks like the following code:
#include <cstdlib>
#include <iostream>
#include <mach/mach_port.h>
#include <IOKit/IOKitLib.h>
#include <IOKit/IOTypes.h>
#include <IOKit/IOKitKeys.h>
#include <IOKit/IOCFPlugIn.h>
#include <IOKit/usb/IOUSBLib.h>
std::string get_descriptor_idx(IOUSBDeviceInterface **dev, UInt8 idx);
int main(int argc, char *argv[]) {
/*
* Get the IO registry
*/
auto entry = IORegistryGetRootEntry(kIOMasterPortDefault);
if (entry == 0)
return EXIT_FAILURE;
io_iterator_t iter{};
auto kret = IORegistryEntryCreateIterator(entry, kIOUSBPlane, kIORegistryIterateRecursively, &iter);
if (kret != KERN_SUCCESS || iter == 0)
return EXIT_FAILURE;
io_service_t service {};
std::cout << std::endl;
while ((service = IOIteratorNext(iter))) {
IOCFPlugInInterface **plug = nullptr;
IOUSBDeviceInterface **dev = nullptr;
io_string_t path;
SInt32 score = 0;
IOReturn ioret;
kret = IOCreatePlugInInterfaceForService(service, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &plug, &score);
IOObjectRelease(service);
if (kret != KERN_SUCCESS || plug == nullptr) {
continue;
}
/*
* USB
*/
ioret = (*plug)->QueryInterface(plug, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID),
static_cast<LPVOID *>((void *) &dev));
(*plug)->Release(plug);
if (ioret != kIOReturnSuccess || dev == nullptr) {
continue;
}
if (IORegistryEntryGetPath(service, kIOServicePlane, path) != KERN_SUCCESS) {
(*dev)->Release(dev);
continue;
}
std::cout << "USB Path: " << path << std::endl;
UInt8 si;
UInt16 u16v;
if ((*dev)->GetDeviceVendor(dev, &u16v) == kIOReturnSuccess)
std::cout << "VID: "<< u16v << std::endl;
if ((*dev)->GetDeviceProduct(dev, &u16v) == kIOReturnSuccess)
std::cout << "PID: "<< u16v << std::endl;
if ((*dev)->USBGetManufacturerStringIndex(dev, &si) == kIOReturnSuccess) {
std::cout << "Manufacturer: " << get_descriptor_idx(dev, si) << std::endl;
}
if ((*dev)->USBGetProductStringIndex(dev, &si) == kIOReturnSuccess) {
std::cout << "Product: " << get_descriptor_idx(dev, si) << std::endl;
}
(*dev)->Release(dev);
std::cout << std::endl;
}
IOObjectRelease(iter);
return 0;
}
/* a quick version */
std::string get_descriptor_idx(IOUSBDeviceInterface **dev, UInt8 idx)
{
IOUSBDevRequest request;
IOReturn ioret;
char buffer[4086] = { 0 };
CFStringRef cfstr;
CFIndex len;
request.bmRequestType = USBmakebmRequestType(kUSBIn, kUSBStandard, kUSBDevice);
request.bRequest = kUSBRqGetDescriptor;
request.wValue = (kUSBStringDesc << 8) | idx;
request.wIndex = 0x409;
request.wLength = sizeof(buffer);
request.pData = buffer;
ioret = (*dev)->DeviceRequest(dev, &request);
if (ioret != kIOReturnSuccess)
return "n/a";
if (request.wLenDone <= 2)
return "n/a";
cfstr = CFStringCreateWithBytes(nullptr, (const UInt8 *)buffer+2, request.wLenDone-2, kCFStringEncodingUTF16LE, 0);
len = CFStringGetMaximumSizeForEncoding(CFStringGetLength(cfstr), kCFStringEncodingUTF8) + 1;
if (len < 0) {
CFRelease(cfstr);
return "n/a";
}
std::string str; str.resize(len);
CFStringGetCString(cfstr, str.data(), len, kCFStringEncodingUTF8);
CFRelease(cfstr);
return str;
}
In my case the result ıs:
USB Path: IOService:/AppleARMPE/arm-io/xxxx/USB2.1 Hub#01100000
VID: 1507
PID: 1552
Manufacturer: GenesysLogic
Product: USB2.1 USB