camera_device_enumerator_main.c

 
#include <winpr/cast.h>
 
#include <freerdp/config.h>
 
#include <freerdp/freerdp.h>
#include <freerdp/channels/log.h>
#include <freerdp/server/rdpecam-enumerator.h>
 
#define TAG CHANNELS_TAG("rdpecam-enumerator.server")
 
typedef enum
{
  ENUMERATOR_INITIAL,
  ENUMERATOR_OPENED,
} eEnumeratorChannelState;
 
typedef struct
{
  CamDevEnumServerContext context;
 
  HANDLE stopEvent;
 
  HANDLE thread;
  void* enumerator_channel;
 
  DWORD SessionId;
 
  BOOL isOpened;
  BOOL externalThread;
 
  /* Channel state */
  eEnumeratorChannelState state;
 
  wStream* buffer;
} enumerator_server;
 
static UINT enumerator_server_initialize(CamDevEnumServerContext* context, BOOL externalThread)
{
  UINT error = CHANNEL_RC_OK;
  enumerator_server* enumerator = (enumerator_server*)context;
 
  WINPR_ASSERT(enumerator);
 
  if (enumerator->isOpened)
  {
    WLog_WARN(TAG, "Application error: Camera Device Enumerator channel already initialized, "
                   "calling in this state is not possible!");
    return ERROR_INVALID_STATE;
  }
 
  enumerator->externalThread = externalThread;
 
  return error;
}
 
static UINT enumerator_server_open_channel(enumerator_server* enumerator)
{
  CamDevEnumServerContext* context = &enumerator->context;
  DWORD Error = ERROR_SUCCESS;
  HANDLE hEvent = NULL;
  DWORD BytesReturned = 0;
  PULONG pSessionId = NULL;
  UINT32 channelId = 0;
  BOOL status = TRUE;
 
  WINPR_ASSERT(enumerator);
 
  if (WTSQuerySessionInformationA(enumerator->context.vcm, WTS_CURRENT_SESSION, WTSSessionId,
                                  (LPSTR*)&pSessionId, &BytesReturned) == FALSE)
  {
    WLog_ERR(TAG, "WTSQuerySessionInformationA failed!");
    return ERROR_INTERNAL_ERROR;
  }
 
  enumerator->SessionId = (DWORD)*pSessionId;
  WTSFreeMemory(pSessionId);
  hEvent = WTSVirtualChannelManagerGetEventHandle(enumerator->context.vcm);
 
  if (WaitForSingleObject(hEvent, 1000) == WAIT_FAILED)
  {
    Error = GetLastError();
    WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "!", Error);
    return Error;
  }
 
  enumerator->enumerator_channel = WTSVirtualChannelOpenEx(
      enumerator->SessionId, RDPECAM_CONTROL_DVC_CHANNEL_NAME, WTS_CHANNEL_OPTION_DYNAMIC);
  if (!enumerator->enumerator_channel)
  {
    Error = GetLastError();
    WLog_ERR(TAG, "WTSVirtualChannelOpenEx failed with error %" PRIu32 "!", Error);
    return Error;
  }
 
  channelId = WTSChannelGetIdByHandle(enumerator->enumerator_channel);
 
  IFCALLRET(context->ChannelIdAssigned, status, context, channelId);
  if (!status)
  {
    WLog_ERR(TAG, "context->ChannelIdAssigned failed!");
    return ERROR_INTERNAL_ERROR;
  }
 
  return Error;
}
 
static UINT enumerator_server_handle_select_version_request(CamDevEnumServerContext* context,
                                                            wStream* s,
                                                            const CAM_SHARED_MSG_HEADER* header)
{
  CAM_SELECT_VERSION_REQUEST pdu = { 0 };
  UINT error = CHANNEL_RC_OK;
 
  WINPR_ASSERT(context);
  WINPR_ASSERT(header);
 
  pdu.Header = *header;
 
  IFCALLRET(context->SelectVersionRequest, error, context, &pdu);
  if (error)
    WLog_ERR(TAG, "context->SelectVersionRequest failed with error %" PRIu32 "", error);
 
  return error;
}
 
static UINT enumerator_server_recv_device_added_notification(CamDevEnumServerContext* context,
                                                             wStream* s,
                                                             const CAM_SHARED_MSG_HEADER* header)
{
  CAM_DEVICE_ADDED_NOTIFICATION pdu;
  UINT error = CHANNEL_RC_OK;
  size_t remaining_length = 0;
  WCHAR* channel_name_start = 0;
 
  WINPR_ASSERT(context);
  WINPR_ASSERT(header);
 
  pdu.Header = *header;
 
  /*
   * RequiredLength 4:
   *
   * Nullterminator DeviceName (2),
   * VirtualChannelName (>= 1),
   * Nullterminator VirtualChannelName (1)
   */
  if (!Stream_CheckAndLogRequiredLength(TAG, s, 4))
    return ERROR_NO_DATA;
 
  pdu.DeviceName = Stream_Pointer(s);
 
  remaining_length = Stream_GetRemainingLength(s);
  channel_name_start = Stream_Pointer(s);
 
  /* Search for null terminator of DeviceName */
  size_t i = 0;
  for (; i < remaining_length; i += sizeof(WCHAR), ++channel_name_start)
  {
    if (*channel_name_start == L'\0')
      break;
  }
 
  if (*channel_name_start != L'\0')
  {
    WLog_ERR(TAG, "enumerator_server_recv_device_added_notification: Invalid DeviceName!");
    return ERROR_INVALID_DATA;
  }
 
  pdu.VirtualChannelName = (char*)++channel_name_start;
  ++i;
 
  if (i >= remaining_length || *pdu.VirtualChannelName == '\0')
  {
    WLog_ERR(TAG,
             "enumerator_server_recv_device_added_notification: Invalid VirtualChannelName!");
    return ERROR_INVALID_DATA;
  }
 
  char* tmp = pdu.VirtualChannelName;
  for (; i < remaining_length; ++i, ++tmp)
  {
    if (*tmp == '\0')
      break;
  }
 
  if (*tmp != '\0')
  {
    WLog_ERR(TAG,
             "enumerator_server_recv_device_added_notification: Invalid VirtualChannelName!");
    return ERROR_INVALID_DATA;
  }
 
  IFCALLRET(context->DeviceAddedNotification, error, context, &pdu);
  if (error)
    WLog_ERR(TAG, "context->DeviceAddedNotification failed with error %" PRIu32 "", error);
 
  return error;
}
 
static UINT enumerator_server_recv_device_removed_notification(CamDevEnumServerContext* context,
                                                               wStream* s,
                                                               const CAM_SHARED_MSG_HEADER* header)
{
  CAM_DEVICE_REMOVED_NOTIFICATION pdu;
  UINT error = CHANNEL_RC_OK;
  size_t remaining_length = 0;
 
  WINPR_ASSERT(context);
  WINPR_ASSERT(header);
 
  pdu.Header = *header;
 
  if (!Stream_CheckAndLogRequiredLength(TAG, s, 2))
    return ERROR_NO_DATA;
 
  pdu.VirtualChannelName = Stream_Pointer(s);
 
  remaining_length = Stream_GetRemainingLength(s);
  char* tmp = pdu.VirtualChannelName + 1;
 
  for (size_t i = 1; i < remaining_length; ++i, ++tmp)
  {
    if (*tmp == '\0')
      break;
  }
 
  if (*tmp != '\0')
  {
    WLog_ERR(TAG,
             "enumerator_server_recv_device_removed_notification: Invalid VirtualChannelName!");
    return ERROR_INVALID_DATA;
  }
 
  IFCALLRET(context->DeviceRemovedNotification, error, context, &pdu);
  if (error)
    WLog_ERR(TAG, "context->DeviceRemovedNotification failed with error %" PRIu32 "", error);
 
  return error;
}
 
static UINT enumerator_process_message(enumerator_server* enumerator)
{
  BOOL rc = 0;
  UINT error = ERROR_INTERNAL_ERROR;
  ULONG BytesReturned = 0;
  CAM_SHARED_MSG_HEADER header = { 0 };
  wStream* s = NULL;
 
  WINPR_ASSERT(enumerator);
  WINPR_ASSERT(enumerator->enumerator_channel);
 
  s = enumerator->buffer;
  WINPR_ASSERT(s);
 
  Stream_SetPosition(s, 0);
  rc = WTSVirtualChannelRead(enumerator->enumerator_channel, 0, NULL, 0, &BytesReturned);
  if (!rc)
    goto out;
 
  if (BytesReturned < 1)
  {
    error = CHANNEL_RC_OK;
    goto out;
  }
 
  if (!Stream_EnsureRemainingCapacity(s, BytesReturned))
  {
    WLog_ERR(TAG, "Stream_EnsureRemainingCapacity failed!");
    error = CHANNEL_RC_NO_MEMORY;
    goto out;
  }
 
  if (WTSVirtualChannelRead(enumerator->enumerator_channel, 0, Stream_BufferAs(s, char),
                            (ULONG)Stream_Capacity(s), &BytesReturned) == FALSE)
  {
    WLog_ERR(TAG, "WTSVirtualChannelRead failed!");
    goto out;
  }
 
  Stream_SetLength(s, BytesReturned);
  if (!Stream_CheckAndLogRequiredLength(TAG, s, CAM_HEADER_SIZE))
    return ERROR_NO_DATA;
 
  Stream_Read_UINT8(s, header.Version);
  Stream_Read_UINT8(s, header.MessageId);
 
  switch (header.MessageId)
  {
    case CAM_MSG_ID_SelectVersionRequest:
      error =
          enumerator_server_handle_select_version_request(&enumerator->context, s, &header);
      break;
    case CAM_MSG_ID_DeviceAddedNotification:
      error =
          enumerator_server_recv_device_added_notification(&enumerator->context, s, &header);
      break;
    case CAM_MSG_ID_DeviceRemovedNotification:
      error = enumerator_server_recv_device_removed_notification(&enumerator->context, s,
                                                                 &header);
      break;
    default:
      WLog_ERR(TAG, "enumerator_process_message: unknown or invalid MessageId %" PRIu8 "",
               header.MessageId);
      break;
  }
 
out:
  if (error)
    WLog_ERR(TAG, "Response failed with error %" PRIu32 "!", error);
 
  return error;
}
 
static UINT enumerator_server_context_poll_int(CamDevEnumServerContext* context)
{
  enumerator_server* enumerator = (enumerator_server*)context;
  UINT error = ERROR_INTERNAL_ERROR;
 
  WINPR_ASSERT(enumerator);
 
  switch (enumerator->state)
  {
    case ENUMERATOR_INITIAL:
      error = enumerator_server_open_channel(enumerator);
      if (error)
        WLog_ERR(TAG, "enumerator_server_open_channel failed with error %" PRIu32 "!",
                 error);
      else
        enumerator->state = ENUMERATOR_OPENED;
      break;
    case ENUMERATOR_OPENED:
      error = enumerator_process_message(enumerator);
      break;
    default:
      break;
  }
 
  return error;
}
 
static HANDLE enumerator_server_get_channel_handle(enumerator_server* enumerator)
{
  void* buffer = NULL;
  DWORD BytesReturned = 0;
  HANDLE ChannelEvent = NULL;
 
  WINPR_ASSERT(enumerator);
 
  if (WTSVirtualChannelQuery(enumerator->enumerator_channel, WTSVirtualEventHandle, &buffer,
                             &BytesReturned) == TRUE)
  {
    if (BytesReturned == sizeof(HANDLE))
      ChannelEvent = *(HANDLE*)buffer;
 
    WTSFreeMemory(buffer);
  }
 
  return ChannelEvent;
}
 
static DWORD WINAPI enumerator_server_thread_func(LPVOID arg)
{
  DWORD nCount = 0;
  HANDLE events[2] = { 0 };
  enumerator_server* enumerator = (enumerator_server*)arg;
  UINT error = CHANNEL_RC_OK;
  DWORD status = 0;
 
  WINPR_ASSERT(enumerator);
 
  nCount = 0;
  events[nCount++] = enumerator->stopEvent;
 
  while ((error == CHANNEL_RC_OK) && (WaitForSingleObject(events[0], 0) != WAIT_OBJECT_0))
  {
    switch (enumerator->state)
    {
      case ENUMERATOR_INITIAL:
        error = enumerator_server_context_poll_int(&enumerator->context);
        if (error == CHANNEL_RC_OK)
        {
          events[1] = enumerator_server_get_channel_handle(enumerator);
          nCount = 2;
        }
        break;
      case ENUMERATOR_OPENED:
        status = WaitForMultipleObjects(nCount, events, FALSE, INFINITE);
        switch (status)
        {
          case WAIT_OBJECT_0:
            break;
          case WAIT_OBJECT_0 + 1:
          case WAIT_TIMEOUT:
            error = enumerator_server_context_poll_int(&enumerator->context);
            break;
 
          case WAIT_FAILED:
          default:
            error = ERROR_INTERNAL_ERROR;
            break;
        }
        break;
      default:
        break;
    }
  }
 
  (void)WTSVirtualChannelClose(enumerator->enumerator_channel);
  enumerator->enumerator_channel = NULL;
 
  if (error && enumerator->context.rdpcontext)
    setChannelError(enumerator->context.rdpcontext, error,
                    "enumerator_server_thread_func reported an error");
 
  ExitThread(error);
  return error;
}
 
static UINT enumerator_server_open(CamDevEnumServerContext* context)
{
  enumerator_server* enumerator = (enumerator_server*)context;
 
  WINPR_ASSERT(enumerator);
 
  if (!enumerator->externalThread && (enumerator->thread == NULL))
  {
    enumerator->stopEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
    if (!enumerator->stopEvent)
    {
      WLog_ERR(TAG, "CreateEvent failed!");
      return ERROR_INTERNAL_ERROR;
    }
 
    enumerator->thread =
        CreateThread(NULL, 0, enumerator_server_thread_func, enumerator, 0, NULL);
    if (!enumerator->thread)
    {
      WLog_ERR(TAG, "CreateThread failed!");
      (void)CloseHandle(enumerator->stopEvent);
      enumerator->stopEvent = NULL;
      return ERROR_INTERNAL_ERROR;
    }
  }
  enumerator->isOpened = TRUE;
 
  return CHANNEL_RC_OK;
}
 
static UINT enumerator_server_close(CamDevEnumServerContext* context)
{
  UINT error = CHANNEL_RC_OK;
  enumerator_server* enumerator = (enumerator_server*)context;
 
  WINPR_ASSERT(enumerator);
 
  if (!enumerator->externalThread && enumerator->thread)
  {
    (void)SetEvent(enumerator->stopEvent);
 
    if (WaitForSingleObject(enumerator->thread, INFINITE) == WAIT_FAILED)
    {
      error = GetLastError();
      WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "", error);
      return error;
    }
 
    (void)CloseHandle(enumerator->thread);
    (void)CloseHandle(enumerator->stopEvent);
    enumerator->thread = NULL;
    enumerator->stopEvent = NULL;
  }
  if (enumerator->externalThread)
  {
    if (enumerator->state != ENUMERATOR_INITIAL)
    {
      (void)WTSVirtualChannelClose(enumerator->enumerator_channel);
      enumerator->enumerator_channel = NULL;
      enumerator->state = ENUMERATOR_INITIAL;
    }
  }
  enumerator->isOpened = FALSE;
 
  return error;
}
 
static UINT enumerator_server_context_poll(CamDevEnumServerContext* context)
{
  enumerator_server* enumerator = (enumerator_server*)context;
 
  WINPR_ASSERT(enumerator);
 
  if (!enumerator->externalThread)
    return ERROR_INTERNAL_ERROR;
 
  return enumerator_server_context_poll_int(context);
}
 
static BOOL enumerator_server_context_handle(CamDevEnumServerContext* context, HANDLE* handle)
{
  enumerator_server* enumerator = (enumerator_server*)context;
 
  WINPR_ASSERT(enumerator);
  WINPR_ASSERT(handle);
 
  if (!enumerator->externalThread)
    return FALSE;
  if (enumerator->state == ENUMERATOR_INITIAL)
    return FALSE;
 
  *handle = enumerator_server_get_channel_handle(enumerator);
 
  return TRUE;
}
 
static UINT enumerator_server_packet_send(CamDevEnumServerContext* context, wStream* s)
{
  enumerator_server* enumerator = (enumerator_server*)context;
  UINT error = CHANNEL_RC_OK;
  ULONG written = 0;
 
  const size_t len = Stream_GetPosition(s);
  WINPR_ASSERT(len <= UINT32_MAX);
  if (!WTSVirtualChannelWrite(enumerator->enumerator_channel, Stream_BufferAs(s, char),
                              (UINT32)len, &written))
  {
    WLog_ERR(TAG, "WTSVirtualChannelWrite failed!");
    error = ERROR_INTERNAL_ERROR;
    goto out;
  }
 
  if (written < Stream_GetPosition(s))
  {
    WLog_WARN(TAG, "Unexpected bytes written: %" PRIu32 "/%" PRIuz "", written,
              Stream_GetPosition(s));
  }
 
out:
  Stream_Free(s, TRUE);
  return error;
}
 
static UINT enumerator_send_select_version_response_pdu(
    CamDevEnumServerContext* context, const CAM_SELECT_VERSION_RESPONSE* selectVersionResponse)
{
  wStream* s = NULL;
 
  s = Stream_New(NULL, CAM_HEADER_SIZE);
  if (!s)
  {
    WLog_ERR(TAG, "Stream_New failed!");
    return ERROR_NOT_ENOUGH_MEMORY;
  }
 
  Stream_Write_UINT8(s, selectVersionResponse->Header.Version);
  Stream_Write_UINT8(s,
                     WINPR_ASSERTING_INT_CAST(uint8_t, selectVersionResponse->Header.MessageId));
 
  return enumerator_server_packet_send(context, s);
}
 
CamDevEnumServerContext* cam_dev_enum_server_context_new(HANDLE vcm)
{
  enumerator_server* enumerator = (enumerator_server*)calloc(1, sizeof(enumerator_server));
 
  if (!enumerator)
    return NULL;
 
  enumerator->context.vcm = vcm;
  enumerator->context.Initialize = enumerator_server_initialize;
  enumerator->context.Open = enumerator_server_open;
  enumerator->context.Close = enumerator_server_close;
  enumerator->context.Poll = enumerator_server_context_poll;
  enumerator->context.ChannelHandle = enumerator_server_context_handle;
 
  enumerator->context.SelectVersionResponse = enumerator_send_select_version_response_pdu;
 
  enumerator->buffer = Stream_New(NULL, 4096);
  if (!enumerator->buffer)
    goto fail;
 
  return &enumerator->context;
fail:
  WINPR_PRAGMA_DIAG_PUSH
  WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC
  cam_dev_enum_server_context_free(&enumerator->context);
  WINPR_PRAGMA_DIAG_POP
  return NULL;
}
 
void cam_dev_enum_server_context_free(CamDevEnumServerContext* context)
{
  enumerator_server* enumerator = (enumerator_server*)context;
 
  if (enumerator)
  {
    enumerator_server_close(context);
    Stream_Free(enumerator->buffer, TRUE);
  }
 
  free(enumerator);
}