I know MIDI allows me to read the state of a MIDI Foot Controller by catching a MIDI Message indicating a Control Change. But what if the user has not touched/changed the control yet? Am I still able to read the state/value? What would be the way to do that?
This is my code for catching Midi Messages using OSX CoreMIDI
void initMidi()
{
MIDIClientRef midiClient;
MIDIPortRef inputPort;
OSStatus status;
MIDIEndpointRef src;
status = MIDIClientCreate(CFSTR("testing"), NULL, NULL, &midiClient);
if (status != noErr)
NSLog(#"Error creating MIDI client: %d", status);
status = MIDIInputPortCreate(midiClient, CFSTR("Input"), midiInputCallback, NULL, &inputPort);
if (status != noErr)
NSLog(#"Error creating MIDI input port: %d", status);
ItemCount numOfDevices = MIDIGetNumberOfDevices();
// just try to connect to every device
for (ItemCount i = 0; i < numOfDevices; i++) {
src = MIDIGetSource(i);
status = MIDIPortConnectSource(inputPort, src, NULL);
}
}
void midiInputCallback(const MIDIPacketList *list,
void *procRef,
void *srcRef)
{
for (UInt32 i = 0; i < list->numPackets; i++) {
const MIDIPacket *packet = &list->packet[i];
for (UInt16 j = 0, size = 0; j < packet->length; j += size) {
UInt8 status = packet->data[j];
if (status < 0xC0) size = 3;
else if (status < 0xE0) size = 2;
else if (status < 0xF0) size = 3;
else if (status < 0xF3) size = 3;
else if (status == 0xF3) size = 2;
else size = 1;
switch (status & 0xF0) {
case 0xb0:
NSLog(#"MIDI Control Changed: %d %d", packet->data[j + 1], packet->data[j + 2]);
break;
}
}
}
}
If you did not reset the device, and did not change a control, then your program does not know the state of a control until it receives a message.
Some devices might have vendor-specific commands to read the current state of a control, or to dump the entire state.
The short answer is - No - you cannot know until an event occurs
Other answers are correct, if you have IN and OUT connected to a controller that allows interrogation through SysEx messages (Manufacturer specific)
To be more helpful:
The default state of all controllers (you are wanting to use) should be OFF on startup
e.g. Pitch Bend = centered, Modulation = ZERO, Sustain = OFF etc…
This has been the state of play since 1980's so it is not been a real problem
If you have your foot down (on a pedal) before you start your app you will be in sync the moment you release it
Good luck
Related
Here is my audio init code. My app responds when queue buffers are ready, but all data in buffer is zero. Checking sound in system preferences shows that USB Audio CODEC in sound input dialog is active. AudioInit() is called right after app launches.
{
#pragma mark user data struct
typedef struct MyRecorder
{
AudioFileID recordFile;
SInt64 recordPacket;
Float32 *pSampledData;
MorseDecode *pMorseDecoder;
} MyRecorder;
#pragma mark utility functions
void CheckError(OSStatus error, const char *operation)
{
if(error == noErr) return;
char errorString[20];
// see if it appears to be a 4 char code
*(UInt32*)(errorString + 1) = CFSwapInt32HostToBig(error);
if (isprint(errorString[1]) && isprint(errorString[2]) &&
isprint(errorString[3]) && isprint(errorString[4]))
{
errorString[0] = errorString[5] = '\'';
errorString[6] = '\0';
}
else
{
sprintf(errorString, "%d", (int)error);
}
fprintf(stderr, "Error: %s (%s)\n", operation, errorString);
}
OSStatus MyGetDefaultInputDeviceSampleRate(Float64 *outSampleRate)
{
OSStatus error;
AudioDeviceID deviceID = 0;
AudioObjectPropertyAddress propertyAddress;
UInt32 propertySize;
propertyAddress.mSelector = kAudioHardwarePropertyDefaultInputDevice;
propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
propertyAddress.mElement = 0;
propertySize = sizeof(AudioDeviceID);
error = AudioObjectGetPropertyData(kAudioObjectSystemObject,
&propertyAddress,
0,
NULL,
&propertySize,
&deviceID);
if(error)
return error;
propertyAddress.mSelector = kAudioDevicePropertyNominalSampleRate;
propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
propertyAddress.mElement = 0;
propertySize = sizeof(Float64);
error = AudioObjectGetPropertyData(deviceID,
&propertyAddress,
0,
NULL,
&propertySize,
outSampleRate);
return error;
}
static int MyComputeRecordBufferSize(const AudioStreamBasicDescription *format,
AudioQueueRef queue,
float seconds)
{
int packets, frames, bytes;
frames = (int)ceil(seconds * format->mSampleRate);
if(format->mBytesPerFrame > 0)
{
bytes = frames * format->mBytesPerFrame;
}
else
{
UInt32 maxPacketSize;
if(format->mBytesPerPacket > 0)
{
// constant packet size
maxPacketSize = format->mBytesPerPacket;
}
else
{
// get the largest single packet size possible
UInt32 propertySize = sizeof(maxPacketSize);
CheckError(AudioQueueGetProperty(queue,
kAudioConverterPropertyMaximumOutputPacketSize,
&maxPacketSize,
&propertySize),
"Couldn't get queues max output packet size");
}
if(format->mFramesPerPacket > 0)
packets = frames / format->mFramesPerPacket;
else
// worst case scenario: 1 frame in a packet
packets = frames;
// sanity check
if(packets == 0)
packets = 1;
bytes = packets * maxPacketSize;
}
return bytes;
}
extern void bridgeToMainThread(MorseDecode *pDecode);
static int callBacks = 0;
// ---------------------------------------------
static void MyAQInputCallback(void *inUserData,
AudioQueueRef inQueue,
AudioQueueBufferRef inBuffer,
const AudioTimeStamp *inStartTime,
UInt32 inNumPackets,
const AudioStreamPacketDescription *inPacketDesc)
{
MyRecorder *recorder = (MyRecorder*)inUserData;
Float32 *pAudioData = (Float32*)(inBuffer->mAudioData);
recorder->pMorseDecoder->pBuffer = pAudioData;
recorder->pMorseDecoder->bufferSize = inNumPackets;
bridgeToMainThread(recorder->pMorseDecoder);
CheckError(AudioQueueEnqueueBuffer(inQueue,
inBuffer,
0,
NULL),
"AudioQueueEnqueueBuffer failed");
printf("packets = %ld, bytes = %ld\n",(long)inNumPackets,(long)inBuffer->mAudioDataByteSize);
callBacks++;
//printf("\ncallBacks = %d\n",callBacks);
//if(callBacks == 0)
//audioStop();
}
static AudioQueueRef queue = {0};
static MyRecorder recorder = {0};
static AudioStreamBasicDescription recordFormat;
void audioInit()
{
// set up format
memset(&recordFormat,0,sizeof(recordFormat));
recordFormat.mFormatID = kAudioFormatLinearPCM;
recordFormat.mChannelsPerFrame = 2;
recordFormat.mBitsPerChannel = 32;
recordFormat.mBytesPerPacket = recordFormat.mBytesPerFrame = recordFormat.mChannelsPerFrame * sizeof(Float32);
recordFormat.mFramesPerPacket = 1;
//recordFormat.mFormatFlags = kAudioFormatFlagsCanonical;
recordFormat.mFormatFlags = kAudioFormatFlagsNativeFloatPacked;
MyGetDefaultInputDeviceSampleRate(&recordFormat.mSampleRate);
UInt32 propSize = sizeof(recordFormat);
CheckError(AudioFormatGetProperty(kAudioFormatProperty_FormatInfo,
0,
NULL,
&propSize,
&recordFormat),
"AudioFormatProperty failed");
recorder.pMorseDecoder = MorseDecode::pInstance();
recorder.pMorseDecoder->m_sampleRate = recordFormat.mSampleRate;
// recorder.pMorseDecoder->setCircularBuffer();
//set up queue
CheckError(AudioQueueNewInput(&recordFormat,
MyAQInputCallback,
&recorder,
NULL,
kCFRunLoopCommonModes,
0,
&queue),
"AudioQueueNewInput failed");
UInt32 size = sizeof(recordFormat);
CheckError(AudioQueueGetProperty(queue,
kAudioConverterCurrentOutputStreamDescription,
&recordFormat,
&size), "Couldn't get queue's format");
// set up buffers and enqueue
const int kNumberRecordBuffers = 3;
int bufferByteSize = MyComputeRecordBufferSize(&recordFormat, queue, AUDIO_BUFFER_DURATION);
for(int bufferIndex = 0; bufferIndex < kNumberRecordBuffers; bufferIndex++)
{
AudioQueueBufferRef buffer;
CheckError(AudioQueueAllocateBuffer(queue,
bufferByteSize,
&buffer),
"AudioQueueAllocateBuffer failed");
CheckError(AudioQueueEnqueueBuffer(queue,
buffer,
0,
NULL),
"AudioQueueEnqueueBuffer failed");
}
}
void audioRun()
{
CheckError(AudioQueueStart(queue, NULL), "AudioQueueStart failed");
}
void audioStop()
{
CheckError(AudioQueuePause(queue), "AudioQueuePause failed");
}
}
This sounds like the new macOS 'microphone privacy' setting, which, if set to 'no access' for your app, will cause precisely this behaviour. So:
Open the System Preferences pane.
Click on 'Security and Privacy'.
Select the Privacy tab.
Click on 'Microphone' in the left-hand pane.
Locate your app in the right-hand pane and tick the checkbox next to it.
Then restart your app and test it.
Tedious, no?
Edit: As stated in the comments, you can't directly request microphone access, but you can detect whether it has been granted to your app or not by calling [AVCaptureDevice authorizationStatusForMediaType: AVMediaTypeAudio].
In Linux, I have a USB hub with the 'register' shown in the image below. This register is supposed to disable power on a certain port on the hub.
I tried to use LibUSB ( my code is shown below ) to write the register, 0x0A, with all zeros to disable all ports. The problem is, the hub is controlled by the standard Linux USB Hub driver and so the Kernel driver is detached. The write also fails. The failure messages are shown below.
Error messages:
$ /mnt/apps/UsbPowerControl
5 Devices in list.
Vendor:Device = 1908:1320
Vendor:Device = 0403:6001
Vendor:Device = 289d:0010
Vendor:Device = 0424:2513
Vendor:Device = 1d6b:0002
Opening Device = 0424:2513
Device Opened
Kernel Driver Active
Kernel Driver Detached!
Claimed Interface
Data-><-
Writing Data...
libusb: error [submit_bulk_transfer] submiturb failed error -1 errno=2
Write Error
Released Interface
How can I use LibUSB to write this Hub register, to dynamically disable and enable the ports, without unregistering the Linux driver and having my write fail?
#include <iostream>
#include <cassert>
#include <libusb-1.0/libusb.h>
using namespace std;
#define VENDOR_ID 0x0424
#define PRODUCT_ID 0x2513
int main() {
libusb_device **devs; //pointer to pointer of device, used to retrieve a list of devices
libusb_device_handle *dev_handle; //a device handle
libusb_context *ctx = NULL; //a libusb session
int r; //for return values
ssize_t cnt; //holding number of devices in list
r = libusb_init(&ctx); //initialize the library for the session we just declared
if(r < 0) {
cout<<"Init Error "<<r<<endl; //there was an error
return 1;
}
libusb_set_debug(ctx, 3); //set verbosity level to 3, as suggested in the documentation
cnt = libusb_get_device_list(ctx, &devs); //get the list of devices
if(cnt < 0) {
cout<<"Get Device Error"<<endl; //there was an error
return 1;
}
cout<<cnt<<" Devices in list."<<endl;
for (size_t idx = 0; idx < cnt; ++idx) {
libusb_device *device = devs[idx];
libusb_device_descriptor desc = {0};
int rc = libusb_get_device_descriptor(device, &desc);
assert(rc == 0);
printf("Vendor:Device = %04x:%04x\n", desc.idVendor, desc.idProduct);
}
printf("Opening Device = %04x:%04x\n", VENDOR_ID, PRODUCT_ID);
dev_handle = libusb_open_device_with_vid_pid(ctx, VENDOR_ID, PRODUCT_ID); //these are vendorID and productID I found for my usb device
if(dev_handle == NULL)
cout<<"Cannot open device"<<endl;
else
cout<<"Device Opened"<<endl;
libusb_free_device_list(devs, 1); //free the list, unref the devices in it
unsigned char *data = new unsigned char[1]; //data to write
data[0]=0b00000000;
int actual; //used to find out how many bytes were written
if(libusb_kernel_driver_active(dev_handle, 0) == 1) { //find out if kernel driver is attached
cout<<"Kernel Driver Active"<<endl;
if(libusb_detach_kernel_driver(dev_handle, 0) == 0) //detach it
cout<<"Kernel Driver Detached!"<<endl;
}
r = libusb_claim_interface(dev_handle, 0); //claim interface 0 (the first) of device (mine had jsut 1)
if(r < 0) {
cout<<"Cannot Claim Interface"<<endl;
return 1;
}
cout<<"Claimed Interface"<<endl;
cout<<"Data->"<<data<<"<-"<<endl; //just to see the data we want to write : abcd
cout<<"Writing Data..."<<endl;
r = libusb_bulk_transfer(dev_handle, (0x0A | LIBUSB_ENDPOINT_OUT), data, 1, &actual, 0); //my device's out endpoint was 2, found with trial- the device had 2 endpoints: 2 and 129
if(r == 0 && actual == 1) //we wrote the 1 bytes successfully
cout<<"Writing Successful!"<<endl;
else
cout<<"Write Error"<<endl;
r = libusb_release_interface(dev_handle, 0); //release the claimed interface
if(r!=0) {
cout<<"Cannot Release Interface"<<endl;
return 1;
}
cout<<"Released Interface"<<endl;
libusb_close(dev_handle); //close the device we opened
libusb_exit(ctx); //needs to be called to end the
delete[] data; //delete the allocated memory for data
return 0;
}
int libusb_detach_kernel_driver ( libusb_device_handle * dev,
int interface_number
)
...
If successful, you will then be able to claim the interface and perform I/O.
...
int libusb_kernel_driver_active ( libusb_device_handle * dev,
int interface_number
)
...
If a kernel driver is active, you cannot claim the interface, and libusb will be unable to perform I/O.
...
Due to what is written above, the short answer to the question "How to do I/O without detaching driver" is "You can't".
Why write fails? This is another matter. I'd suggest looking into a number of things:
Check out the value returned from libusb_bulk_transfer, maybe it will give you the idea of what is happening.
Sounds stupid, but I always check it out before anything else: process privileges.
Also, I can suggest another way of approaching the solution, namely sysfs.
I assume that your device(am I right?) supports EEPROM and SMBus access. It means that this support should be manifested in the kernel somewhere around /sys/bus/i2c/devices/[some_device_id]/eeprom (probably another device number, another directory position, etc, because it is all driver-related), but if it can be found and read just as any other file (which is likely, unless something is wrong with the device), then it probably should be able to write into it as well. If the read works, then I suggest to compare the hexdump -C of the found file to the datasheet, and if the data seems legit, try writing directly into your register(file offset).
Anyway, accessing character device files and sysfs files is a general way of accessing drivers' data in linux. Probably you don't even need to use libusb's API to write that single byte.
I am developing an application that reads data from a named pipe on Windows 7 at around 800 Mbps. I have to develop it with several threads since the FIFO at the other side of the pipe overflows if I am not able to read at the given speed. The performance though is really pitifull and I cannot understand why. I already read several things I tried to split the memory to avoid bad memory sharing.
At the beginning I has thinking I could be a problem with contiguous memory possitions, but the memory sections are queued in a list the main thread is not using them any more after queue it. The amount of memory are huge so I don't thing they lay on same pages or so.
This is the threaded function:
void splitMessage(){
char* bufferMSEO;
char* bufferMDO;
std::list<struct msgBufferStr*> localBufferList;
while(1)
{
long bytesProcessed = 0;
{
std::unique_lock<std::mutex> lk(bufferMutex);
while(bufferList.empty())
{
// Wait until the map has data
listReady.wait(lk);
}
//Extract the data from the list and copy to the local list
localBufferList.splice(localBufferList.end(),bufferList);
//Unlock the mutex and notify
// Manual unlocking is done before notifying, to avoid waking up
// the waiting thread only to block again (see notify_one for details)
lk.unlock();
//listReady.notify_one();
}
for(auto nextBuffer = localBufferList.begin(); nextBuffer != localBufferList.end(); nextBuffer++)
{
//nextBuffer = it->second();
bufferMDO = (*nextBuffer)->MDO;
bufferMSEO = (*nextBuffer)->MSEO;
bytesProcessed += (*nextBuffer)->size;
//Process the data Stream
for(int k=0; k<(*nextBuffer)->size; k++)
{
}
//localBufferList.remove(*nextBuffer);
free(bufferMDO);
free(bufferMSEO);
free(*nextBuffer);
}
localBufferList.clear();
}
}
And here the thread that reads the data and queue them:
DWORD WINAPI InstanceThread(LPVOID lpvParam)
// This routine is a thread processing function to read from and reply to a client
// via the open pipe connection passed from the main loop. Note this allows
// the main loop to continue executing, potentially creating more threads of
// of this procedure to run concurrently, depending on the number of incoming
// client connections.
{
HANDLE hHeap = GetProcessHeap();
TCHAR* pchRequest = (TCHAR*)HeapAlloc(hHeap, 0, BUFSIZE*sizeof(TCHAR));
DWORD cbBytesRead = 0, cbReplyBytes = 0, cbWritten = 0;
BOOL fSuccess = FALSE;
HANDLE hPipe = NULL;
double totalRxData = 0;
char* bufferPnt;
char* bufferMDO;
char* bufferMSEO;
char* destPnt;
// Do some extra error checking since the app will keep running even if this
// thread fails.
if (lpvParam == NULL)
{
printf( "\nERROR - Pipe Server Failure:\n");
printf( " InstanceThread got an unexpected NULL value in lpvParam.\n");
printf( " InstanceThread exitting.\n");
if (pchRequest != NULL) HeapFree(hHeap, 0, pchRequest);
return (DWORD)-1;
}
if (pchRequest == NULL)
{
printf( "\nERROR - Pipe Server Failure:\n");
printf( " InstanceThread got an unexpected NULL heap allocation.\n");
printf( " InstanceThread exitting.\n");
return (DWORD)-1;
}
// Print verbose messages. In production code, this should be for debugging only.
printf("InstanceThread created, receiving and processing messages.\n");
// The thread's parameter is a handle to a pipe object instance.
hPipe = (HANDLE) lpvParam;
try
{
msgSplitter = std::thread(&splitMessage);
//msgSplitter.detach();
}
catch(...)
{
_tprintf(TEXT("CreateThread failed, GLE=%d.\n"), GetLastError());
return -1;
}
while (1)
{
struct msgBufferStr *newBuffer = (struct msgBufferStr* )malloc(sizeof(struct msgBufferStr));
// Read client requests from the pipe. This simplistic code only allows messages
// up to BUFSIZE characters in length.
fSuccess = ReadFile(
hPipe, // handle to pipe
pchRequest, // buffer to receive data
BUFSIZE*sizeof(TCHAR), // size of buffer
&cbBytesRead, // number of bytes read
NULL); // not overlapped I/O
if (!fSuccess || cbBytesRead == 0)
{
if (GetLastError() == ERROR_BROKEN_PIPE)
{
_tprintf(TEXT("InstanceThread: client disconnected.\n"), GetLastError());
break;
}
else if (GetLastError() == ERROR_MORE_DATA)
{
}
else
{
_tprintf(TEXT("InstanceThread ReadFile failed, GLE=%d.\n"), GetLastError());
}
}
//timeStart = omp_get_wtime();
bufferPnt = (char*)pchRequest;
totalRxData += ((double)cbBytesRead)/1000000;
bufferMDO = (char*) malloc(cbBytesRead);
bufferMSEO = (char*) malloc(cbBytesRead/3);
destPnt = bufferMDO;
//#pragma omp parallel for
for(int i = 0; i < cbBytesRead/12; i++)
{
msgCounter++;
if(*(bufferPnt + (i * 12)) == 0) continue;
if(*(bufferPnt + (i * 12)) == 8)
{
errorCounter++;
continue;
}
//Use 64 bits variables in order to make less operations
unsigned long long *sourceAddrLong = (unsigned long long*) (bufferPnt + (i * 12));
unsigned long long *destPntLong = (unsigned long long*) (destPnt + (i * 8));
//Copy the data bytes from source to destination
*destPntLong = *sourceAddrLong;
//Copy and prepare the MSEO lines for the data processing
bufferMSEO[i*4]=(bufferPnt[(i * 12) + 8] & 0x03);
bufferMSEO[i*4 + 1]=(bufferPnt[(i * 12) + 8] & 0x0C) >> 2;
bufferMSEO[i*4 + 2]=(bufferPnt[(i * 12) + 8] & 0x30) >> 4;
bufferMSEO[i*4 + 3]=(bufferPnt[(i * 12) + 8] & 0xC0) >> 6;
}
newBuffer->size = cbBytesRead/3;
newBuffer->MDO = bufferMDO;
newBuffer->MSEO = bufferMSEO;
{
//lock the mutex
std::lock_guard<std::mutex> lk(bufferMutex);
//add data to the list
bufferList.push_back(newBuffer);
} // bufferMutex is automatically released when lk goes out of scope
//Notify
listReady.notify_one();
}
// Flush the pipe to allow the client to read the pipe's contents
// before disconnecting. Then disconnect the pipe, and close the
// handle to this pipe instance.
FlushFileBuffers(hPipe);
DisconnectNamedPipe(hPipe);
CloseHandle(hPipe);
HeapFree(hHeap, 0, pchRequest);
//Show memory leak isues
_CrtDumpMemoryLeaks();
//TODO: Join thread
printf("InstanceThread exitting.\n");
return 1;
}
The think that really blows my mind is that I a let it like this the splitMessage thread takes minutes to read the data even though the first thread finished reading the data long ago. I mean the read thread reads like 1,5Gb or information in seconds and waits for more data from the pipe. This data are processed by the split thread (the only one really "doing" something in almost one minute or more). The CPU is moreover only to less than 20% percent used. (It is a i7 labtop with 16 Gb RAM and 8 cores!)
On the other hand, if I just comment the for loop in the process thread:
for(int k=0; k<(*nextBuffer)->size; k++)
Then the data are read slowly and the FIFO on the other side of the pipe overflows. With 8 processors and at more than 2 GHz should be fast enought to go throw the buffers without many problems, isn't it? I think it has to be a memory access issue or that the scheduler is sending the thread somehow to sleep but I cannot figure out why!!. Other possibility is that the iteration throw the linked list with the iterator is not optimal.
Any help would be geat because I am trying to understand it since a couple of days, I made several changes in the code and tried to simplified at the maximum and I am getting crazy :).
best regards,
Manuel
I need to determine is there hardware keylogger that was plugged to PC with USB keyboard. It needs to be done via software method, from user-land. However wiki says that it is impossible to detect HKL using soft, there are several methods exists. The best and I think only one overiew that present in net relating that theme is "Detecting Hardware Keyloggers, by Fabian Mihailowitsch - youtube".
Using this overview I am developing a tool to detect USB hardware keyloggers. The sources for detecting PS/2 keyloggers was already shared by author and available here. So my task is to make it worked for USB only.
As suggested I am using libusb library to interfere with USB devices in system.
So, there are methods I had choosen in order to detect HKL:
Find USB keyboard that bugged by HKL. Note that HKL is usually
invisible from device list in system or returned by libusb.
Detect Keyghost HKL by: Interrupt read from USB HID device, send usb reset (libusb_reset_device), read interrupt again. If data returned on last read is not nulls then keylogger detected. It is described on page 45 of Mihailowitsch's presentation
Time measurement. The idea is measure time of send/receive packets using control transfer for original keyboard for thousands times. In case HKL has been plugged, program will measure time again and then compare the time with the original value. For HKL it have to be much(or not so much) greater.
Algorithm is:
Send an output report to Keyboard(as Control transfer) (HID_REPORT_TYPE_OUTPUT 0x02 )
Wait for ACKed packet
Repeat Loop (10.000 times)
Measure time
Below is my code according to steps of detection.
1. Find USB keyboard
libusb_device * UsbKeyboard::GetSpecifiedDevice(PredicateType pred)
{
if (_usbDevices == nullptr) return nullptr;
int i = 0;
libusb_device *dev = nullptr;
while ((dev = _usbDevices[i++]) != NULL)
{
struct libusb_device_descriptor desc;
int r = libusb_get_device_descriptor(dev, &desc);
if (r >= 0)
{
if (pred(desc))
return dev;
}
}
return nullptr;
}
libusb_device * UsbKeyboard::FindKeyboard()
{
return GetSpecifiedDevice([&](libusb_device_descriptor &desc) {
bool isKeyboard = false;
auto dev_handle = libusb_open_device_with_vid_pid(_context, desc.idVendor, desc.idProduct);
if (dev_handle != nullptr)
{
unsigned char buf[255] = "";
// product description contains 'Keyboard', usually string is 'USB Keyboard'
if (libusb_get_string_descriptor_ascii(dev_handle, desc.iProduct, buf, sizeof(buf)) >= 0)
isKeyboard = strstr((char*)buf, "Keyboard") != nullptr;
libusb_close(dev_handle);
}
return isKeyboard;
});
}
Here we're iterating through all USB devices in system and checks their Product string. In my system this string for keyboard is 'USB keyboard' (obviously).
Is it stable way to detect keyboard through Product string? Is there other ways?
2. Detect Keyghost HKL using Interrupt read
int UsbKeyboard::DetectKeyghost(libusb_device *kbdev)
{
int r, i;
int transferred;
unsigned char answer[PACKET_INT_LEN];
unsigned char question[PACKET_INT_LEN];
for (i = 0; i < PACKET_INT_LEN; i++) question[i] = 0x40 + i;
libusb_device_handle *devh = nullptr;
if ((r = libusb_open(kbdev, &devh)) < 0)
{
ShowError("Error open device", r);
return r;
}
r = libusb_set_configuration(devh, 1);
if (r < 0)
{
ShowError("libusb_set_configuration error ", r);
goto out;
}
printf("Successfully set usb configuration 1\n");
r = libusb_claim_interface(devh, 0);
if (r < 0)
{
ShowError("libusb_claim_interface error ", r);
goto out;
}
r = libusb_interrupt_transfer(devh, 0x81 , answer, PACKET_INT_LEN,
&transferred, TIMEOUT);
if (r < 0)
{
ShowError("Interrupt read error ", r);
goto out;
}
if (transferred < PACKET_INT_LEN)
{
ShowError("Interrupt transfer short read %", r);
goto out;
}
for (i = 0; i < PACKET_INT_LEN; i++) {
if (i % 8 == 0)
printf("\n");
printf("%02x, %02x; ", question[i], answer[i]);
}
printf("\n");
out:
libusb_close(devh);
return 0;
}
I've got such error on libusb_interrupt_transfer:
libusb: error [hid_submit_bulk_transfer] HID transfer failed: [5] Access denied
Interrupt read error - Input/Output Error (LIBUSB_ERROR_IO) (GetLastError() - 1168)
No clue why 'access denied', then IO error, and GetLastError() returns 1168, which means - Element not found (What element?). Looking for help here.
Time measurement. Send output report and wait for ACK packet.
int UsbKeyboard::SendOutputReport(libusb_device *kbdev)
{
const int PACKET_INT_LEN = 1;
int r, i;
unsigned char answer[PACKET_INT_LEN];
unsigned char question[PACKET_INT_LEN];
for (i = 0; i < PACKET_INT_LEN; i++) question[i] = 0x30 + i;
for (i = 1; i < PACKET_INT_LEN; i++) answer[i] = 0;
libusb_device_handle *devh = nullptr;
if ((r = libusb_open(kbdev, &devh)) < 0)
{
ShowError("Error open device", r);
return r;
}
r = libusb_set_configuration(devh, 1);
if (r < 0)
{
ShowError("libusb_set_configuration error ", r);
goto out;
}
printf("Successfully set usb configuration 1\n");
r = libusb_claim_interface(devh, 0);
if (r < 0)
{
ShowError("libusb_claim_interface error ", r);
goto out;
}
printf("Successfully claim interface\n");
r = libusb_control_transfer(devh, CTRL_OUT, HID_SET_REPORT, (HID_REPORT_TYPE_OUTPUT << 8) | 0x00, 0, question, PACKET_INT_LEN, TIMEOUT);
if (r < 0) {
ShowError("Control Out error ", r);
goto out;
}
r = libusb_control_transfer(devh, CTRL_IN, HID_GET_REPORT, (HID_REPORT_TYPE_INPUT << 8) | 0x00, 0, answer, PACKET_INT_LEN, TIMEOUT);
if (r < 0) {
ShowError("Control In error ", r);
goto out;
}
out:
libusb_close(devh);
return 0;
}
Error the same as for read interrupt:
Control Out error - Input/Output Error (LIBUSB_ERROR_IO) (GetLastError() - 1168
)
How to fix please? Also how to wait for ACK packet?
Thank you.
UPDATE:
I've spent a day on searching and debbuging. So currently my problem is only to
send Output report via libusb_control_transfer. The 2nd method with interrupt read is unnecessary to implement because of Windows denies access to read from USB device using ReadFile.
It is only libusb stuff left, here is the code I wanted to make work (from 3rd example):
// sending Output report (LED)
// ...
unsigned char buf[65];
buf[0] = 1; // First byte is report number
buf[1] = 0x80;
r = libusb_control_transfer(devh, CTRL_OUT,
HID_SET_REPORT/*0x9*/, (HID_REPORT_TYPE_OUTPUT/*0x2*/ << 8) | 0x00,
0, buf, (uint16_t)2, 1000);
...
The error I've got:
[ 0.309018] [00001c0c] libusb: debug [_hid_set_report] Failed to Write HID Output Report: [1] Incorrect function
Control Out error - Input/Output Error (LIBUSB_ERROR_IO) (GetLastError() - 1168)
This error occures right after DeviceIoControl call in libusb internals.
What means "Incorrect function" there?
I am having a problem with a Serial Port communication between Arduino Nano and C++, even though the problem is in C++ side. Basically I want to send integers (or long,...) from the Arduino to a C++ program to be processed.
First I did a test sending information from the Arduino to the computer using Matlab. The Arduino code is pretty simple:
int i = 0;
void setup() {
// start serial port at 9600 bps:
Serial.begin(9600);
establishContact();
}
void loop() {
Serial.println(i);
i=i+1;
delay(10);
}
void establishContact() {
while (Serial.available() <= 0) {
Serial.println('A', BYTE);
delay(10);
}
}
The Matlab side is also simple:
clc;
clear all;
numSec=2;
t=[];
v=[];
s1 = serial('COM3'); % define serial port
s1.BaudRate=9600; % define baud rate
set(s1, 'terminator', 'LF'); % define the terminator for println
fopen(s1);
try % use try catch to ensure fclose
% signal the arduino to start collection
w=fscanf(s1,'%s'); % must define the input % d or %s, etc.
if (w=='A')
display(['Collecting data']);
fprintf(s1,'%s\n','A'); % establishContact just wants
% something in the buffer
end
i=0;
t0=tic;
while (toc(t0)<=numSec)
i=i+1;
t(i)=toc(t0);
t(i)=t(i)-t(1);
v(i)=fscanf(s1,'%d');
end
fclose(s1);
plot(t,v,'*r')
catch me
fclose(s1);
end
My goal is, with C++, do the same that is done in Matlab using fscanf(s1, '%d').
Here is the current code that I am using (C++ code):
void main()
{
HANDLE hSerial;
hSerial = CreateFile(TEXT("COM3"),
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,//FILE_FLAG_OVERLAPPED,
NULL);
if ( hSerial == INVALID_HANDLE_VALUE)
{
printf("Error initializing handler");
}
else
{
// Set the parameters of the handler to the serial port.
DCB dcb = {0};
dcb.DCBlength = sizeof(dcb);
if ( !GetCommState(hSerial, &dcb) )
{
printf("Error setting parameters");
}
FillMemory(&dcb, sizeof(dcb), 0);
dcb.BaudRate = CBR_9600;
dcb.ByteSize = 8;
dcb.StopBits = ONESTOPBIT;
dcb.Parity = NOPARITY;
if ( !SetCommState(hSerial, &dcb) )
{
// error setting serial port state.
}
// Tell the program not to wait for data to show up
COMMTIMEOUTS timeouts = {0};
timeouts.ReadIntervalTimeout = 0;//20;
timeouts.ReadTotalTimeoutConstant = 0;//20;
timeouts.ReadTotalTimeoutMultiplier = 0;//50;
timeouts.WriteTotalTimeoutConstant = 0;//100;
timeouts.WriteTotalTimeoutMultiplier = 0;//100;
if ( !SetCommTimeouts(hSerial, &timeouts) )
{
printf("Error setting the timeouts");
}
char szBuff[5] = "";
DWORD dwBytesRead = 0;
int i = 0;
char test[] = "B\n";
int maxSamples = 10;
DWORD dwCommStatus;
WriteFile(hSerial, test, 2, &dwBytesRead, NULL);
SetCommMask(hSerial,EV_RXCHAR);
while (i < maxSamples)
{
WaitCommEvent (hSerial, &dwCommStatus, 0);
if (dwCommStatus & EV_RXCHAR)
{
memset(szBuff,0,sizeof(szBuff));
ReadFile(hSerial, LPVOID(szBuff), 4, &dwBytesRead, NULL);
cout<<szBuff;
printf(" - %d - \n", atoi(szBuff));
}
i++;
}
scanf("%d", &i);
CloseHandle(hSerial);
}
}
The goal of my code would be something like num = ReadSerialCOM(hSerial, "%d");
My current C++ code reads the information from the buffer, but there is not an accepted end of line, which implies that my numbers (integers) are received cut.
Eg:
I send 8889 from the Arduino, which places it in the COM port. And the command ReadFile saves '88' into szBuff. At the next iteration '89\n' is saved into sZBuff. Basically I want to avoid to post-process sZBuff to concat '88' and '89\n'.
Anyone?
Thanks!
If I understand your question correctly, one way to avoid having to 'post-process' is to move the pointer passed to ReadFile to the end of the available data, so the ReadFile call is appending to the buffer, instead of overwriting.
Essentially, you would have two pointers. One to the buffer, the other to the end of the data in the buffer. So when your program starts, both pointers will be the same. Now, you read the first 2 bytes. You increment the end-of-data pointer by 2. You do another read, but instead of szBuff, you pass a pointer to the end of the previously read data. You read the next three bytes and you have the complete entry in szBuff.
If you need to wait until some delimiter to mark the end of an entry is received, you could just search the received data for it. If it's not there, you keep reading until you find it. If it is there, you can just return.
// Fill the buffer with 0
char szBuff[256] = {0};
// We have no data in the buffer, so the end of data points to the beginning
// of the buffer.
char* szEndOfData = szBuff;
while (i < maxSamples)
{
WaitCommEvent (hSerial, &dwCommStatus, 0);
if (dwCommStatus & EV_RXCHAR)
{
// Append up to 4 bytes from the serial port to the buffer
ReadFile(hSerial, LPVOID(szEndOfData), 4, &dwBytesRead, NULL);
// Increment the end of data pointer, so it points to the end of the
// data available in the buffer.
szEndOfData += dwBytesRead;
cout<<szBuff;
printf(" - %d - \n", atoi(szBuff));
}
i++;
}
// Output, assuming what you mentioned happens:
// - 88 -
// - 8889 -
If this approach is acceptable to you, it will require a bit more work. For example, you would have to ensure you don't overflow your buffer. When you remove data from the buffer, you'll have to move all of the data after the removed segment to the beginning, and fix the end of data pointer. Alternatively, you could use a circular buffer.
As Hans Passant and dauphic pointed, it doesn't seem to be a general solution for my question. I am writing, though, the code that I was trying to avoid, just in case somebody finds it useful or face the same problem that I had:
int i = 0;
DWORD dwBytesRead = 0;
DWORD dwCommStatus = 0;
char szBuff[2] = "";
int maxRead = 20;
int sizeNum = 1;
int *num = (int*)malloc(maxRead*sizeof(int));
char *currNum;
char *pastNum;
// Write something into the Serial Port to start receive
// information from the Arduino
WriteFile(hSerial, (LPCVOID)"A\0", 1, &dwBytesRead, NULL);
SetCommMask(hSerial, EV_RXCHAR);
// Start reading from the Serial Port
while ( i < maxRead )
{
WaitCommEvent (hSerial, &dwCommStatus, 0);
if (dwCommStatus & EV_RXCHAR) // if a char is received in the serial port
{
ReadFile(hSerial, LPVOID(szBuff), 1, &dwBytesRead, NULL);
if ( szBuff[0] > 47 && szBuff[0] < 58 )
{
sizeNum++;
if (sizeNum ==2)
{
currNum = (char*)malloc(sizeNum*sizeof(char));
strcpy(currNum, szBuff);
} else
{
if (pastNum != NULL)
free(pastNum);
pastNum = currNum;
currNum = (char*)malloc(sizeNum*sizeof(char));
strcpy(currNum, pastNum);
strcpy(currNum+(sizeNum-2)*sizeof(char), szBuff);
}
cout << szBuff<<endl;
} else if (szBuff[0] == '\n' && sizeNum > 1) // end of number
{
num[i] = atoi(currNum);
i++;
sizeNum = 1;
if (currNum!=NULL)
free(currNum);
}
}
}