server/encomsp_main.c

 
#include <freerdp/config.h>
 
#include <winpr/crt.h>
#include <winpr/print.h>
#include <winpr/stream.h>
 
#include <freerdp/freerdp.h>
#include <freerdp/channels/log.h>
 
#include "encomsp_main.h"
 
#define TAG CHANNELS_TAG("encomsp.server")
 
static UINT encomsp_read_header(wStream* s, ENCOMSP_ORDER_HEADER* header)
{
  if (!Stream_CheckAndLogRequiredLength(TAG, s, ENCOMSP_ORDER_HEADER_SIZE))
    return ERROR_INVALID_DATA;
 
  Stream_Read_UINT16(s, header->Type);   /* Type (2 bytes) */
  Stream_Read_UINT16(s, header->Length); /* Length (2 bytes) */
  return CHANNEL_RC_OK;
}
 
static UINT encomsp_recv_change_participant_control_level_pdu(EncomspServerContext* context,
                                                              wStream* s,
                                                              const ENCOMSP_ORDER_HEADER* header)
{
  ENCOMSP_CHANGE_PARTICIPANT_CONTROL_LEVEL_PDU pdu = WINPR_C_ARRAY_INIT;
  UINT error = CHANNEL_RC_OK;
 
  const size_t pos = Stream_GetPosition(s);
  if (pos < ENCOMSP_ORDER_HEADER_SIZE)
    return ERROR_INVALID_PARAMETER;
 
  const size_t beg = pos - ENCOMSP_ORDER_HEADER_SIZE;
  CopyMemory(&pdu, header, sizeof(ENCOMSP_ORDER_HEADER));
 
  if (!Stream_CheckAndLogRequiredLength(TAG, s, 6))
    return ERROR_INVALID_DATA;
 
  Stream_Read_UINT16(s, pdu.Flags);         /* Flags (2 bytes) */
  Stream_Read_UINT32(s, pdu.ParticipantId); /* ParticipantId (4 bytes) */
  const size_t end = Stream_GetPosition(s);
 
  if ((beg + header->Length) < end)
  {
    WLog_ERR(TAG, "Not enough data!");
    return ERROR_INVALID_DATA;
  }
 
  if ((beg + header->Length) > end)
  {
    if (!Stream_CheckAndLogRequiredLength(TAG, s, (size_t)((beg + header->Length) - end)))
      return ERROR_INVALID_DATA;
 
    if (!Stream_SetPosition(s, (beg + header->Length)))
      return ERROR_INVALID_DATA;
  }
 
  IFCALLRET(context->ChangeParticipantControlLevel, error, context, &pdu);
 
  if (error)
    WLog_ERR(TAG, "context->ChangeParticipantControlLevel failed with error %" PRIu32 "",
             error);
 
  return error;
}
 
static UINT encomsp_server_receive_pdu(EncomspServerContext* context, wStream* s)
{
  UINT error = CHANNEL_RC_OK;
 
  while (Stream_GetRemainingLength(s) > 0)
  {
    ENCOMSP_ORDER_HEADER header = WINPR_C_ARRAY_INIT;
    if ((error = encomsp_read_header(s, &header)))
    {
      WLog_ERR(TAG, "encomsp_read_header failed with error %" PRIu32 "!", error);
      return error;
    }
 
    WLog_INFO(TAG, "EncomspReceive: Type: %" PRIu16 " Length: %" PRIu16 "", header.Type,
              header.Length);
 
    switch (header.Type)
    {
      case ODTYPE_PARTICIPANT_CTRL_CHANGED:
        if ((error =
                 encomsp_recv_change_participant_control_level_pdu(context, s, &header)))
        {
          WLog_ERR(TAG,
                   "encomsp_recv_change_participant_control_level_pdu failed with error "
                   "%" PRIu32 "!",
                   error);
          return error;
        }
 
        break;
 
      default:
        WLog_ERR(TAG, "header.Type unknown %" PRIu16 "!", header.Type);
        return ERROR_INVALID_DATA;
    }
  }
 
  return error;
}
 
static DWORD WINAPI encomsp_server_thread(LPVOID arg)
{
  wStream* s = nullptr;
  DWORD nCount = 0;
  void* buffer = nullptr;
  HANDLE events[8];
  HANDLE ChannelEvent = nullptr;
  DWORD BytesReturned = 0;
  ENCOMSP_ORDER_HEADER* header = nullptr;
  EncomspServerContext* context = nullptr;
  UINT error = CHANNEL_RC_OK;
  DWORD status = 0;
  context = (EncomspServerContext*)arg;
 
  buffer = nullptr;
  BytesReturned = 0;
  ChannelEvent = nullptr;
  s = Stream_New(nullptr, 4096);
 
  if (!s)
  {
    WLog_ERR(TAG, "Stream_New failed!");
    error = CHANNEL_RC_NO_MEMORY;
    goto out;
  }
 
  if (WTSVirtualChannelQuery(context->priv->ChannelHandle, WTSVirtualEventHandle, &buffer,
                             &BytesReturned) == TRUE)
  {
    if (BytesReturned == sizeof(HANDLE))
      ChannelEvent = *(HANDLE*)buffer;
 
    WTSFreeMemory(buffer);
  }
 
  nCount = 0;
  events[nCount++] = ChannelEvent;
  events[nCount++] = context->priv->StopEvent;
 
  while (1)
  {
    status = WaitForMultipleObjects(nCount, events, FALSE, INFINITE);
 
    if (status == WAIT_FAILED)
    {
      error = GetLastError();
      WLog_ERR(TAG, "WaitForMultipleObjects failed with error %" PRIu32 "", error);
      break;
    }
 
    status = WaitForSingleObject(context->priv->StopEvent, 0);
 
    if (status == WAIT_FAILED)
    {
      error = GetLastError();
      WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "", error);
      break;
    }
 
    if (status == WAIT_OBJECT_0)
    {
      break;
    }
 
    if (!WTSVirtualChannelRead(context->priv->ChannelHandle, 0, nullptr, 0, &BytesReturned))
    {
      WLog_ERR(TAG, "WTSVirtualChannelRead failed!");
      error = ERROR_INTERNAL_ERROR;
      break;
    }
 
    if (BytesReturned < 1)
      continue;
 
    if (!Stream_EnsureRemainingCapacity(s, BytesReturned))
    {
      WLog_ERR(TAG, "Stream_EnsureRemainingCapacity failed!");
      error = CHANNEL_RC_NO_MEMORY;
      break;
    }
 
    const size_t cap = Stream_Capacity(s);
    if ((cap > UINT32_MAX) ||
        !WTSVirtualChannelRead(context->priv->ChannelHandle, 0, Stream_BufferAs(s, char),
                               (ULONG)cap, &BytesReturned))
    {
      WLog_ERR(TAG, "WTSVirtualChannelRead failed!");
      error = ERROR_INTERNAL_ERROR;
      break;
    }
 
    if (Stream_GetPosition(s) >= ENCOMSP_ORDER_HEADER_SIZE)
    {
      header = Stream_BufferAs(s, ENCOMSP_ORDER_HEADER);
 
      if (header->Length >= Stream_GetPosition(s))
      {
        Stream_SealLength(s);
        Stream_ResetPosition(s);
 
        if ((error = encomsp_server_receive_pdu(context, s)))
        {
          WLog_ERR(TAG, "encomsp_server_receive_pdu failed with error %" PRIu32 "!",
                   error);
          break;
        }
 
        Stream_ResetPosition(s);
      }
    }
  }
 
  Stream_Free(s, TRUE);
out:
 
  if (error && context->rdpcontext)
    setChannelError(context->rdpcontext, error, "encomsp_server_thread reported an error");
 
  ExitThread(error);
  return error;
}
 
static UINT encomsp_server_start(EncomspServerContext* context)
{
  context->priv->ChannelHandle =
      WTSVirtualChannelOpen(context->vcm, WTS_CURRENT_SESSION, ENCOMSP_SVC_CHANNEL_NAME);
 
  if (!context->priv->ChannelHandle)
    return CHANNEL_RC_BAD_CHANNEL;
 
  if (!(context->priv->StopEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr)))
  {
    WLog_ERR(TAG, "CreateEvent failed!");
    return ERROR_INTERNAL_ERROR;
  }
 
  if (!(context->priv->Thread =
            CreateThread(nullptr, 0, encomsp_server_thread, (void*)context, 0, nullptr)))
  {
    WLog_ERR(TAG, "CreateThread failed!");
    (void)CloseHandle(context->priv->StopEvent);
    context->priv->StopEvent = nullptr;
    return ERROR_INTERNAL_ERROR;
  }
 
  return CHANNEL_RC_OK;
}
 
static UINT encomsp_server_stop(EncomspServerContext* context)
{
  UINT error = CHANNEL_RC_OK;
  (void)SetEvent(context->priv->StopEvent);
 
  if (WaitForSingleObject(context->priv->Thread, INFINITE) == WAIT_FAILED)
  {
    error = GetLastError();
    WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "", error);
    return error;
  }
 
  (void)CloseHandle(context->priv->Thread);
  (void)CloseHandle(context->priv->StopEvent);
  return error;
}
 
EncomspServerContext* encomsp_server_context_new(HANDLE vcm)
{
  EncomspServerContext* context = nullptr;
  context = (EncomspServerContext*)calloc(1, sizeof(EncomspServerContext));
 
  if (context)
  {
    context->vcm = vcm;
    context->Start = encomsp_server_start;
    context->Stop = encomsp_server_stop;
    context->priv = (EncomspServerPrivate*)calloc(1, sizeof(EncomspServerPrivate));
 
    if (!context->priv)
    {
      WLog_ERR(TAG, "calloc failed!");
      free(context);
      return nullptr;
    }
  }
 
  return context;
}
 
void encomsp_server_context_free(EncomspServerContext* context)
{
  if (context)
  {
    if (context->priv->ChannelHandle != INVALID_HANDLE_VALUE)
      (void)WTSVirtualChannelClose(context->priv->ChannelHandle);
 
    free(context->priv);
    free(context);
  }
}