path: root/src/device/device_io_hid.cpp

// Copyright (c) 2017-2023, The Monero Project
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#if defined(HAVE_HIDAPI) 

#include <boost/scope_exit.hpp>
#include "log.hpp"
#include "device_io_hid.hpp"

namespace hw {
  namespace io {
 
    #undef MONERO_DEFAULT_LOG_CATEGORY
    #define MONERO_DEFAULT_LOG_CATEGORY "device.io"
 
    #define ASSERT_X(exp,msg)    CHECK_AND_ASSERT_THROW_MES(exp, msg); 

    #define MAX_BLOCK  64
    
    static std::string safe_hid_error(hid_device *hwdev) {
      if (hwdev) {
        const wchar_t* error_wstr = hid_error(hwdev);
        if (error_wstr == nullptr)
        {
          return "Unknown error";
        }
        std::mbstate_t state{};
        const size_t len_symbols = std::wcsrtombs(nullptr, &error_wstr, 0, &state);
        if (len_symbols == static_cast<std::size_t>(-1))
        {
          return "Failed to convert wide char error";
        }
        std::string error_str(len_symbols + 1, 0);
        std::wcsrtombs(&error_str[0], &error_wstr, error_str.size(), &state);
        return error_str;
      }
      return std::string("NULL device");
    }

    static std::string safe_hid_path(const hid_device_info *hwdev_info) {
      if (hwdev_info && hwdev_info->path) {
        return  std::string(hwdev_info->path);
      }
      return std::string("NULL path");
    }

    device_io_hid::device_io_hid(unsigned short c, unsigned char t, unsigned int ps, unsigned int to) : 
      channel(c), 
      tag(t), 
      packet_size(ps), 
      timeout(to),
      usb_vid(0),
      usb_pid(0),
      usb_device(NULL) {
    }

    device_io_hid::device_io_hid() : device_io_hid(DEFAULT_CHANNEL, DEFAULT_TAG, DEFAULT_PACKET_SIZE, DEFAULT_TIMEOUT) {
    }

    void device_io_hid::io_hid_log(int read, unsigned char* buffer, int block_len) {
      if (hid_verbose) {
        char  strbuffer[1024];
        hw::buffer_to_str(strbuffer, sizeof(strbuffer), (char*)buffer, block_len);
        MDEBUG( "HID " << (read?"<":">") <<" : "<<strbuffer);
      }
    }
 
    void device_io_hid::init() {
      int r;
      r = hid_init();
      ASSERT_X(r>=0, "Unable to init hidapi library. Error "+std::to_string(r)+": "+safe_hid_error(this->usb_device));
    }

    void device_io_hid::connect(void *params) {
      hid_conn_params *p = (struct hid_conn_params*)params;
      if (!this->connect(p->vid, p->pid, p->interface_number, p->usage_page)) {
        ASSERT_X(false, "No device found");
      }
    }

    void device_io_hid::connect(const std::vector<hid_conn_params> &hcpV) {
      for (auto p: hcpV) {
        if (this->connect(p.vid, p.pid, p.interface_number, p.usage_page)) {
          return;
        }        
      }
      ASSERT_X(false, "No device found");
    }

    hid_device_info *device_io_hid::find_device(hid_device_info *devices_list, boost::optional<int> interface_number, boost::optional<unsigned short> usage_page) {
      bool select_any = !interface_number && !usage_page;

      MDEBUG( "Looking for " <<
              (select_any ? "any HID Device" : "HID Device with") <<
              (interface_number ? (" interface_number " + std::to_string(interface_number.value())) : "") <<
              ((interface_number && usage_page) ? " or" : "") <<
              (usage_page ? (" usage_page " + std::to_string(usage_page.value())) : ""));

      hid_device_info *result = nullptr;
      for (; devices_list != nullptr; devices_list = devices_list->next) {
        BOOST_SCOPE_EXIT(&devices_list, &result) {
          MDEBUG( (result == devices_list ? "SELECTED" : "SKIPPED ") <<
                  " HID Device" <<
                  " path " << safe_hid_path(devices_list) <<
                  " interface_number " << devices_list->interface_number <<
                  " usage_page " << devices_list->usage_page);
        }
        BOOST_SCOPE_EXIT_END

        if (result != nullptr) {
          continue;
        }

        if (select_any) {
          result = devices_list;
        } else if (interface_number && devices_list->interface_number == interface_number.value()) {
          result = devices_list;
        } else if (usage_page && devices_list->usage_page == usage_page.value()) {
          result = devices_list;
        }
      }

      return result;
    }

    hid_device  *device_io_hid::connect(unsigned int vid, unsigned  int pid, boost::optional<int> interface_number, boost::optional<unsigned short> usage_page) {
      hid_device_info *hwdev_info_list;
      hid_device      *hwdev;

      this->disconnect();

      hwdev_info_list = hid_enumerate(vid, pid);
      if (!hwdev_info_list) {
        MDEBUG("Unable to enumerate device "+std::to_string(vid)+":"+std::to_string(vid)+  ": "+ safe_hid_error(this->usb_device));
        return NULL;
      }
      hwdev = NULL;
      if (hid_device_info *device = find_device(hwdev_info_list, interface_number, usage_page)) {
        hwdev = hid_open_path(device->path);
      }
      hid_free_enumeration(hwdev_info_list);
      ASSERT_X(hwdev, "Unable to open device "+std::to_string(pid)+":"+std::to_string(vid));
      this->usb_vid = vid;
      this->usb_pid = pid;
      this->usb_device = hwdev;
      return hwdev;
    }


    bool device_io_hid::connected() const {
      return this->usb_device != NULL;
    }

    int device_io_hid::exchange(unsigned char *command, unsigned int cmd_len, unsigned char *response, unsigned int max_resp_len, bool user_input)  {
      unsigned char buffer[400];
      unsigned char padding_buffer[MAX_BLOCK+1];
      unsigned int  result;
               int  hid_ret;
      unsigned int  remaining;
      unsigned int  offset = 0;

      ASSERT_X(this->usb_device,"No device opened");

      //Split command in several HID packet
      memset(buffer, 0, sizeof(buffer));
      result = this->wrapCommand(command, cmd_len, buffer, sizeof(buffer));
      remaining = result;

      while (remaining > 0) {
        int block_size = (remaining > MAX_BLOCK ? MAX_BLOCK : remaining);
        memset(padding_buffer, 0, sizeof(padding_buffer));
        memcpy(padding_buffer+1, buffer + offset, block_size);
        io_hid_log(0, padding_buffer, block_size+1);
        hid_ret = hid_write(this->usb_device, padding_buffer, block_size+1);
        ASSERT_X(hid_ret>=0, "Unable to send hidapi command. Error "+std::to_string(result)+": "+ safe_hid_error(this->usb_device));
        offset += block_size;
        remaining -= block_size;
      }

      //get first response
      memset(buffer, 0, sizeof(buffer));
      if (!user_input) {
        hid_ret = hid_read_timeout(this->usb_device, buffer, MAX_BLOCK, this->timeout);
      } else {
        hid_ret = hid_read(this->usb_device, buffer, MAX_BLOCK);
      }
      ASSERT_X(hid_ret>=0, "Unable to read hidapi response. Error "+std::to_string(result)+": "+ safe_hid_error(this->usb_device));
      result = (unsigned int)hid_ret;
      io_hid_log(1, buffer, result); 
      offset = MAX_BLOCK;
      //parse first response and get others if any
      for (;;) {
        result = this->unwrapReponse(buffer, offset, response, max_resp_len);
        if (result != 0) {
          break;
        }
        hid_ret = hid_read_timeout(this->usb_device, buffer + offset, MAX_BLOCK, this->timeout);
        ASSERT_X(hid_ret>=0, "Unable to receive hidapi response. Error "+std::to_string(result)+": "+ safe_hid_error(this->usb_device));
        result = (unsigned int)hid_ret;
        io_hid_log(1, buffer + offset, result);
        offset += MAX_BLOCK;
      }      
      return result;
    }

    void device_io_hid::disconnect(void)  {
      if (this->usb_device) {
        hid_close(this->usb_device);
      }
      this->usb_vid = 0;
      this->usb_pid = 0;
      this->usb_device = NULL;
    }

    void device_io_hid::release()  {
      /* Do not exit, as the lib context is global*/
      //hid_exit();
    }

    unsigned int device_io_hid::wrapCommand(const unsigned char *command, size_t command_len, unsigned char *out, size_t out_len) {
      unsigned int sequence_idx = 0;
      unsigned int offset = 0;
      unsigned int offset_out = 0;
      unsigned int block_size;

      ASSERT_X(this->packet_size >= 3, "Invalid Packet size: "+std::to_string(this->packet_size)) ;
      ASSERT_X(out_len >= 7,  "out_len too short: "+std::to_string(out_len));

      out_len -= 7;
      out[offset_out++] = ((this->channel >> 8) & 0xff);
      out[offset_out++] = (this->channel & 0xff);
      out[offset_out++] = this->tag;
      out[offset_out++] = ((sequence_idx >> 8) & 0xff);
      out[offset_out++] = (sequence_idx & 0xff);
      sequence_idx++;
      out[offset_out++] = ((command_len >> 8) & 0xff);
      out[offset_out++] = (command_len & 0xff);
      block_size = (command_len > this->packet_size - 7 ? this->packet_size - 7 : command_len);
      ASSERT_X(out_len >= block_size,  "out_len too short: "+std::to_string(out_len));
      out_len -= block_size;
      memcpy(out + offset_out, command + offset, block_size);
      offset_out += block_size;
      offset += block_size;
      while (offset != command_len) {
        ASSERT_X(out_len >= 5,  "out_len too short: "+std::to_string(out_len));
        out_len -= 5;
        out[offset_out++] = ((this->channel >> 8) & 0xff);
        out[offset_out++] = (this->channel & 0xff);
        out[offset_out++] = this->tag;
        out[offset_out++] = ((sequence_idx >> 8) & 0xff);
        out[offset_out++] = (sequence_idx & 0xff);
        sequence_idx++;
        block_size = ((command_len - offset) > this->packet_size - 5 ? this->packet_size - 5 : command_len - offset);
        ASSERT_X(out_len >= block_size,  "out_len too short: "+std::to_string(out_len));
        out_len -= block_size;
        memcpy(out + offset_out, command + offset, block_size);
        offset_out += block_size;
        offset += block_size;
      }
      while ((offset_out % this->packet_size) != 0) {
        ASSERT_X(out_len >= 1,  "out_len too short: "+std::to_string(out_len));
        out_len--;
        out[offset_out++] = 0;
      }
      return offset_out;
    }

    /*
     * return  0 if more data are needed
    *         >0 if response is fully available
     */
    unsigned int device_io_hid::unwrapReponse(const unsigned char *data, size_t data_len, unsigned char *out, size_t out_len) {
      unsigned int sequence_idx = 0;
      unsigned int offset = 0;
      unsigned int offset_out = 0;
      unsigned int response_len;
      unsigned int block_size;
      unsigned int val;

      //end?
      if ((data == NULL) || (data_len < 7 + 5)) { 
        return 0;
      }

      //check hid header
      val = (data[offset]<<8) + data[offset+1];
      offset += 2;
      ASSERT_X(val == this->channel, "Wrong Channel");
      val =  data[offset];
      offset++;
      ASSERT_X(val == this->tag, "Wrong TAG");      
      val = (data[offset]<<8) + data[offset+1];
      offset += 2;
      ASSERT_X(val == sequence_idx, "Wrong sequence_idx");

      //fetch
      response_len = (data[offset++] << 8);
      response_len |= data[offset++];
      ASSERT_X(out_len >= response_len, "Out Buffer too short");
      if (data_len < (7 + response_len)) {
        return 0;
      }
      block_size = (response_len > (this->packet_size - 7) ? this->packet_size - 7 : response_len);
      memcpy(out + offset_out, data + offset, block_size);
      offset += block_size;
      offset_out += block_size;
      while (offset_out != response_len) {
        sequence_idx++;
        if (offset == data_len) {
          return 0;
        }
        val = (data[offset]<<8) + data[offset+1];
        offset += 2;
        ASSERT_X(val == this->channel, "Wrong Channel");
        val =  data[offset];
        offset++;
        ASSERT_X(val == this->tag, "Wrong TAG");      
        val = (data[offset]<<8) + data[offset+1];
        offset += 2;
        ASSERT_X(val == sequence_idx, "Wrong sequence_idx");

        block_size = ((response_len - offset_out) > this->packet_size - 5 ? this->packet_size - 5 : response_len - offset_out);
        if (block_size > (data_len - offset)) {
          return 0;
        }
        memcpy(out + offset_out, data + offset, block_size);
        offset += block_size;
        offset_out += block_size;
      }
      return offset_out;
    }


  }
}

#endif //#if defined(HAVE_HIDAPI)