/* $Id: HGCM.cpp 109079 2016-07-22 19:16:33Z bird $ */
/** @file
 * VBoxGuestLib - Host-Guest Communication Manager.
 *
 * These public functions can be only used by other drivers. They all
 * do an IOCTL to VBoxGuest via IDC.
 */

/*
 * Copyright (C) 2006-2016 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */

/* Entire file is ifdef'ed with !VBGL_VBOXGUEST */
#ifndef VBGL_VBOXGUEST

#include "VBGLInternal.h"

#include <iprt/assert.h>
#include <iprt/semaphore.h>
#include <iprt/string.h>

#define VBGL_HGCM_ASSERT_MSG AssertReleaseMsg

/**
 * Initializes the HGCM VBGL bits.
 *
 * @return VBox status code.
 */
int vbglR0HGCMInit(void)
{
	return RTSemFastMutexCreate(&g_vbgldata.mutexHGCMHandle);
}

/**
 * Initializes the HGCM VBGL bits.
 *
 * @return VBox status code.
 */
int vbglR0HGCMTerminate(void)
{
	RTSemFastMutexDestroy(g_vbgldata.mutexHGCMHandle);
	g_vbgldata.mutexHGCMHandle = NIL_RTSEMFASTMUTEX;

	return VINF_SUCCESS;
}

DECLINLINE(int)vbglHandleHeapEnter(void)
{
	int rc = RTSemFastMutexRequest(g_vbgldata.mutexHGCMHandle);

	VBGL_HGCM_ASSERT_MSG(RT_SUCCESS(rc),
			     ("Failed to request handle heap mutex, rc = %Rrc\n",
			      rc));

	return rc;
}

DECLINLINE(void)vbglHandleHeapLeave(void)
{
	RTSemFastMutexRelease(g_vbgldata.mutexHGCMHandle);
}

struct VBGLHGCMHANDLEDATA *vbglHGCMHandleAlloc(void)
{
	struct VBGLHGCMHANDLEDATA *p = NULL;
	int rc = vbglHandleHeapEnter();
	if (RT_SUCCESS(rc)) {
		uint32_t i;

		/* Simple linear search in array. This will be called not so often, only connect/disconnect. */
	/** @todo bitmap for faster search and other obvious optimizations. */
		for (i = 0; i < RT_ELEMENTS(g_vbgldata.aHGCMHandleData); i++) {
			if (!g_vbgldata.aHGCMHandleData[i].fAllocated) {
				p = &g_vbgldata.aHGCMHandleData[i];
				p->fAllocated = 1;
				break;
			}
		}

		vbglHandleHeapLeave();

		VBGL_HGCM_ASSERT_MSG(p != NULL, ("Not enough HGCM handles.\n"));
	}
	return p;
}

void vbglHGCMHandleFree(struct VBGLHGCMHANDLEDATA *pHandle)
{
	if (pHandle) {
		int rc = vbglHandleHeapEnter();
		if (RT_SUCCESS(rc)) {
			VBGL_HGCM_ASSERT_MSG(pHandle->fAllocated,
					     ("Freeing not allocated handle.\n"));

			RT_ZERO(*pHandle);
			vbglHandleHeapLeave();
		}
	}
}

DECLVBGL(int) VbglHGCMConnect(VBGLHGCMHANDLE * pHandle,
			      VBoxGuestHGCMConnectInfo * pData)
{
	int rc;
	if (pHandle && pData) {
		struct VBGLHGCMHANDLEDATA *pHandleData = vbglHGCMHandleAlloc();
		if (pHandleData) {
			rc = vbglDriverOpen(&pHandleData->driver);
			if (RT_SUCCESS(rc)) {
				rc = vbglDriverIOCtl(&pHandleData->driver,
						     VBOXGUEST_IOCTL_HGCM_CONNECT,
						     pData, sizeof(*pData));
				if (RT_SUCCESS(rc))
					rc = pData->result;
				if (RT_SUCCESS(rc)) {
					*pHandle = pHandleData;
					return rc;
				}

				vbglDriverClose(&pHandleData->driver);
			}

			vbglHGCMHandleFree(pHandleData);
		} else
			rc = VERR_NO_MEMORY;
	} else
		rc = VERR_INVALID_PARAMETER;
	return rc;
}

DECLVBGL(int)VbglHGCMDisconnect(VBGLHGCMHANDLE handle,
				VBoxGuestHGCMDisconnectInfo * pData)
{
	int rc =
	    vbglDriverIOCtl(&handle->driver, VBOXGUEST_IOCTL_HGCM_DISCONNECT,
			    pData, sizeof(*pData));

	vbglDriverClose(&handle->driver);

	vbglHGCMHandleFree(handle);

	return rc;
}

DECLVBGL(int)VbglHGCMCall(VBGLHGCMHANDLE handle, VBoxGuestHGCMCallInfo * pData,
			  uint32_t cbData)
{
	VBGL_HGCM_ASSERT_MSG(cbData >=
			     sizeof(VBoxGuestHGCMCallInfo) +
			     pData->cParms * sizeof(HGCMFunctionParameter),
			     ("cbData = %d, cParms = %d (calculated size %d)\n",
			      cbData, pData->cParms,
			      sizeof(VBoxGuestHGCMCallInfo) +
			      pData->cParms * sizeof(VBoxGuestHGCMCallInfo)));

	return vbglDriverIOCtl(&handle->driver,
			       VBOXGUEST_IOCTL_HGCM_CALL(cbData), pData,
			       cbData);
}

DECLVBGL(int)VbglHGCMCallUserData(VBGLHGCMHANDLE handle,
				  VBoxGuestHGCMCallInfo * pData,
				  uint32_t cbData)
{
	VBGL_HGCM_ASSERT_MSG(cbData >=
			     sizeof(VBoxGuestHGCMCallInfo) +
			     pData->cParms * sizeof(HGCMFunctionParameter),
			     ("cbData = %d, cParms = %d (calculated size %d)\n",
			      cbData, pData->cParms,
			      sizeof(VBoxGuestHGCMCallInfo) +
			      pData->cParms * sizeof(VBoxGuestHGCMCallInfo)));

	return vbglDriverIOCtl(&handle->driver,
			       VBOXGUEST_IOCTL_HGCM_CALL_USERDATA(cbData),
			       pData, cbData);
}

DECLVBGL(int)VbglHGCMCallTimed(VBGLHGCMHANDLE handle,
			       VBoxGuestHGCMCallInfoTimed * pData,
			       uint32_t cbData)
{
	uint32_t cbExpected = sizeof(VBoxGuestHGCMCallInfoTimed)
	    + pData->info.cParms * sizeof(HGCMFunctionParameter);
	VBGL_HGCM_ASSERT_MSG(cbData >= cbExpected,
			     ("cbData = %d, cParms = %d (calculated size %d)\n",
			      cbData, pData->info.cParms, cbExpected));
	NOREF(cbExpected);

	return vbglDriverIOCtl(&handle->driver,
			       VBOXGUEST_IOCTL_HGCM_CALL_TIMED(cbData), pData,
			       cbData);
}

#endif /* !VBGL_VBOXGUEST */
