/** @file
 * Host-Guest Communication Manager (HGCM) - Service library definitions.
 */

/*
 * 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.
 */

#ifndef ___VBox_hgcm_h
#define ___VBox_hgcm_h

#include <iprt/assert.h>
#include <iprt/string.h>
#include <VBox/cdefs.h>
#include <VBox/types.h>
#include <VBox/err.h>
#ifdef VBOX_TEST_HGCM_PARMS
# include <iprt/test.h>
#endif

/** @todo proper comments. */

/**
 * Service interface version.
 *
 * Includes layout of both VBOXHGCMSVCFNTABLE and VBOXHGCMSVCHELPERS.
 *
 * A service can work with these structures if major version
 * is equal and minor version of service is <= version of the
 * structures.
 *
 * For example when a new helper is added at the end of helpers
 * structure, then the minor version will be increased. All older
 * services still can work because they have their old helpers
 * unchanged.
 *
 * Revision history.
 * 1.1->2.1 Because the pfnConnect now also has the pvClient parameter.
 * 2.1->2.2 Because pfnSaveState and pfnLoadState were added
 * 2.2->3.1 Because pfnHostCall is now synchronous, returns rc, and parameters were changed
 * 3.1->3.2 Because pfnRegisterExtension was added
 * 3.2->3.3 Because pfnDisconnectClient helper was added
 * 3.3->4.1 Because the pvService entry and parameter was added
 * 4.1->4.2 Because the VBOX_HGCM_SVC_PARM_CALLBACK parameter type was added
 * 4.2->5.1 Removed the VBOX_HGCM_SVC_PARM_CALLBACK parameter type, as
 *          this problem is already solved by service extension callbacks
 */
#define VBOX_HGCM_SVC_VERSION_MAJOR (0x0005)
#define VBOX_HGCM_SVC_VERSION_MINOR (0x0001)
#define VBOX_HGCM_SVC_VERSION ((VBOX_HGCM_SVC_VERSION_MAJOR << 16) + VBOX_HGCM_SVC_VERSION_MINOR)


/** Typed pointer to distinguish a call to service. */
struct VBOXHGCMCALLHANDLE_TYPEDEF;
typedef struct VBOXHGCMCALLHANDLE_TYPEDEF *VBOXHGCMCALLHANDLE;

/** Service helpers pointers table. */
typedef struct VBOXHGCMSVCHELPERS
{
    /** The service has processed the Call request. */
    DECLR3CALLBACKMEMBER(void, pfnCallComplete, (VBOXHGCMCALLHANDLE callHandle, int32_t rc));

    void *pvInstance;

    /** The service disconnects the client. */
    DECLR3CALLBACKMEMBER(void, pfnDisconnectClient, (void *pvInstance, uint32_t u32ClientID));
} VBOXHGCMSVCHELPERS;

typedef VBOXHGCMSVCHELPERS *PVBOXHGCMSVCHELPERS;


#define VBOX_HGCM_SVC_PARM_INVALID (0U)
#define VBOX_HGCM_SVC_PARM_32BIT (1U)
#define VBOX_HGCM_SVC_PARM_64BIT (2U)
#define VBOX_HGCM_SVC_PARM_PTR   (3U)

typedef struct VBOXHGCMSVCPARM
{
    /** VBOX_HGCM_SVC_PARM_* values. */
    uint32_t type;

    union
    {
        uint32_t uint32;
        uint64_t uint64;
        struct
        {
            uint32_t size;
            void *addr;
        } pointer;
    } u;
#ifdef __cplusplus
    /** Extract an uint32_t value from an HGCM parameter structure */
    int getUInt32(uint32_t *u32)
    {
        AssertPtrReturn(u32, VERR_INVALID_POINTER);
        int rc = VINF_SUCCESS;
        if (type != VBOX_HGCM_SVC_PARM_32BIT)
            rc = VERR_INVALID_PARAMETER;
        if (RT_SUCCESS(rc))
            *u32 = u.uint32;
        return rc;
    }

    /** Extract a uint64_t value from an HGCM parameter structure */
    int getUInt64(uint64_t *u64)
    {
        AssertPtrReturn(u64, VERR_INVALID_POINTER);
        int rc = VINF_SUCCESS;
        if (type != VBOX_HGCM_SVC_PARM_64BIT)
            rc = VERR_INVALID_PARAMETER;
        if (RT_SUCCESS(rc))
            *u64 = u.uint64;
        return rc;
    }

    /** Extract a pointer value from an HGCM parameter structure */
    int getPointer(void **ppv, uint32_t *pcb)
    {
        AssertPtrReturn(ppv, VERR_INVALID_POINTER);
        AssertPtrReturn(pcb, VERR_INVALID_POINTER);
        if (type == VBOX_HGCM_SVC_PARM_PTR)
        {
            *ppv = u.pointer.addr;
            *pcb = u.pointer.size;
            return VINF_SUCCESS;
        }

        return VERR_INVALID_PARAMETER;
    }

    /** Extract a constant pointer value from an HGCM parameter structure */
    int getPointer(const void **ppcv, uint32_t *pcb)
    {
        AssertPtrReturn(ppcv, VERR_INVALID_POINTER);
        AssertPtrReturn(pcb, VERR_INVALID_POINTER);
        void *pv;
        int rc = getPointer(&pv, pcb);
        *ppcv = pv;
        return rc;
    }

    /** Extract a pointer value to a non-empty buffer from an HGCM parameter
     * structure */
    int getBuffer(void **ppv, uint32_t *pcb)
    {
        AssertPtrReturn(ppv, VERR_INVALID_POINTER);
        AssertPtrReturn(pcb, VERR_INVALID_POINTER);
        void *pv = NULL;
        uint32_t cb = 0;
        int rc = getPointer(&pv, &cb);
        if (   RT_SUCCESS(rc)
            && VALID_PTR(pv)
            && cb > 0)
        {
            *ppv = pv;
            *pcb = cb;
            return VINF_SUCCESS;
        }

        return VERR_INVALID_PARAMETER;
    }

    /** Extract a pointer value to a non-empty constant buffer from an HGCM
     * parameter structure */
    int getBuffer(const void **ppcv, uint32_t *pcb)
    {
        AssertPtrReturn(ppcv, VERR_INVALID_POINTER);
        AssertPtrReturn(pcb, VERR_INVALID_POINTER);
        void *pcv = NULL;
        int rc = getBuffer(&pcv, pcb);
        *ppcv = pcv;
        return rc;
    }

    /** Extract a string value from an HGCM parameter structure */
    int getString(char **ppch, uint32_t *pcb)
    {
        uint32_t cb = 0;
        char *pch = NULL;
        int rc = getBuffer((void **)&pch, &cb);
        if (RT_FAILURE(rc))
        {
            *ppch = NULL;
            *pcb = 0;
            return rc;
        }
        rc = RTStrValidateEncodingEx(pch, cb,
                                     RTSTR_VALIDATE_ENCODING_ZERO_TERMINATED);
        *ppch = pch;
        *pcb = cb;
        return rc;
    }

    /** Extract a constant string value from an HGCM parameter structure */
    int getString(const char **ppch, uint32_t *pcb)
    {
        char *pch = NULL;
        int rc = getString(&pch, pcb);
        *ppch = pch;
        return rc;
    }

    /** Set a uint32_t value to an HGCM parameter structure */
    void setUInt32(uint32_t u32)
    {
        type = VBOX_HGCM_SVC_PARM_32BIT;
        u.uint32 = u32;
    }

    /** Set a uint64_t value to an HGCM parameter structure */
    void setUInt64(uint64_t u64)
    {
        type = VBOX_HGCM_SVC_PARM_64BIT;
        u.uint64 = u64;
    }

    /** Set a pointer value to an HGCM parameter structure */
    void setPointer(void *pv, uint32_t cb)
    {
        type = VBOX_HGCM_SVC_PARM_PTR;
        u.pointer.addr = pv;
        u.pointer.size = cb;
    }

    /** Set a const string value to an HGCM parameter structure */
    void setString(const char *psz)
    {
        type = VBOX_HGCM_SVC_PARM_PTR;
        u.pointer.addr = (void *)psz;
        u.pointer.size = (uint32_t)strlen(psz) + 1;
    }

#ifdef ___iprt_cpp_ministring_h
    /** Set a const string value to an HGCM parameter structure */
    void setCppString(const RTCString &rString)
    {
        type = VBOX_HGCM_SVC_PARM_PTR;
        u.pointer.addr = (void *)rString.c_str();
        u.pointer.size = (uint32_t)rString.length() + 1;
    }
#endif

#ifdef VBOX_TEST_HGCM_PARMS
    /** Test the getString member function.  Indirectly tests the getPointer
     * and getBuffer APIs.
     * @param  hTest  an running IPRT test
     * @param  aType  the type that the parameter should be set to before
     *                calling getString
     * @param  apcc   the value that the parameter should be set to before
     *                calling getString, and also the address (!) which we
     *                expect getString to return.  Stricter than needed of
     *                course, but I was feeling lazy.
     * @param  acb    the size that the parameter should be set to before
     *                calling getString, and also the size which we expect
     *                getString to return.
     * @param  rcExp  the expected return value of the call to getString.
     */
    void doTestGetString(RTTEST hTest, uint32_t aType, const char *apcc,
                         uint32_t acb, int rcExp)
    {
        /* An RTTest API like this, which would print out an additional line
         * of context if a test failed, would be nice.  This is because the
         * line number alone doesn't help much here, given that this is a
         * subroutine called many times. */
        /*
        RTTestContextF(hTest,
                       ("doTestGetString, aType=%u, apcc=%p, acp=%u, rcExp=%Rrc",
                        aType, apcc, acp, rcExp));
         */
        setPointer((void *)apcc, acb);
        type = aType;  /* in case we don't want VBOX_HGCM_SVC_PARM_PTR */
        const char *pcc = NULL;
        uint32_t cb = 0;
        int rc = getString(&pcc, &cb);
        RTTEST_CHECK_RC(hTest, rc, rcExp);
        if (RT_SUCCESS(rcExp))
        {
            RTTEST_CHECK_MSG_RETV(hTest, (pcc == apcc),
                                  (hTest, "expected %p, got %p", apcc, pcc));
            RTTEST_CHECK_MSG_RETV(hTest, (cb == acb),
                                  (hTest, "expected %u, got %u", acb, cb));
        }
    }

    /** Run some unit tests on the getString method and indirectly test
     * getPointer and getBuffer as well. */
    void testGetString(RTTEST hTest)
    {
        RTTestSub(hTest, "HGCM string parameter handling");
        doTestGetString(hTest, VBOX_HGCM_SVC_PARM_32BIT, "test", 3,
                        VERR_INVALID_PARAMETER);
        doTestGetString(hTest, VBOX_HGCM_SVC_PARM_PTR, "test", 5,
                        VINF_SUCCESS);
        doTestGetString(hTest, VBOX_HGCM_SVC_PARM_PTR, "test", 3,
                        VERR_BUFFER_OVERFLOW);
        doTestGetString(hTest, VBOX_HGCM_SVC_PARM_PTR, "test\xf0", 6,
                        VERR_INVALID_UTF8_ENCODING);
        doTestGetString(hTest, VBOX_HGCM_SVC_PARM_PTR, "test", 0,
                        VERR_INVALID_PARAMETER);
        doTestGetString(hTest, VBOX_HGCM_SVC_PARM_PTR, (const char *)0x1, 5,
                        VERR_INVALID_PARAMETER);
        RTTestSubDone(hTest);
    }
#endif

    VBOXHGCMSVCPARM() : type(VBOX_HGCM_SVC_PARM_INVALID) {}
#endif
} VBOXHGCMSVCPARM;

typedef VBOXHGCMSVCPARM *PVBOXHGCMSVCPARM;

#ifdef VBOX_WITH_CRHGSMI
typedef void * HGCMCVSHANDLE;

typedef DECLCALLBACK(void) HGCMHOSTFASTCALLCB (int32_t result, uint32_t u32Function, PVBOXHGCMSVCPARM pParam, void *pvContext);
typedef HGCMHOSTFASTCALLCB *PHGCMHOSTFASTCALLCB;
#endif


/** Service specific extension callback.
 *  This callback is called by the service to perform service specific operation.
 *
 * @param pvExtension The extension pointer.
 * @param u32Function What the callback is supposed to do.
 * @param pvParm      The function parameters.
 * @param cbParm      The size of the function parameters.
 */
typedef DECLCALLBACK(int) FNHGCMSVCEXT(void *pvExtension, uint32_t u32Function, void *pvParm, uint32_t cbParms);
typedef FNHGCMSVCEXT *PFNHGCMSVCEXT;

/** The Service DLL entry points.
 *
 *  HGCM will call the DLL "VBoxHGCMSvcLoad"
 *  function and the DLL must fill in the VBOXHGCMSVCFNTABLE
 *  with function pointers.
 */

/* The structure is used in separately compiled binaries so an explicit packing is required. */
#pragma pack(1) /** @todo r=bird: The pragma pack(1) is not at all required!! */
typedef struct VBOXHGCMSVCFNTABLE
{
    /** @name Filled by HGCM
     * @{ */

    /** Size of the structure. */
    uint32_t                 cbSize;

    /** Version of the structure, including the helpers. */
    uint32_t                 u32Version;

    PVBOXHGCMSVCHELPERS      pHelpers;
    /** @} */

    /** @name Filled in by the service.
     * @{ */

    /** Size of client information the service want to have. */
    uint32_t                 cbClient;
#if ARCH_BITS == 64
    /** Ensure that the following pointers are properly aligned on 64-bit system. */
    uint32_t                 u32Alignment0;
#endif

    /** Uninitialize service */
    DECLR3CALLBACKMEMBER(int, pfnUnload, (void *pvService));

    /** Inform the service about a client connection. */
    DECLR3CALLBACKMEMBER(int, pfnConnect, (void *pvService, uint32_t u32ClientID, void *pvClient));

    /** Inform the service that the client wants to disconnect. */
    DECLR3CALLBACKMEMBER(int, pfnDisconnect, (void *pvService, uint32_t u32ClientID, void *pvClient));

    /** Service entry point.
     *  Return code is passed to pfnCallComplete callback.
     */
    DECLR3CALLBACKMEMBER(void, pfnCall, (void *pvService, VBOXHGCMCALLHANDLE callHandle, uint32_t u32ClientID, void *pvClient, uint32_t function, uint32_t cParms, VBOXHGCMSVCPARM paParms[]));

    /** Host Service entry point meant for privileged features invisible to the guest.
     *  Return code is passed to pfnCallComplete callback.
     */
    DECLR3CALLBACKMEMBER(int, pfnHostCall, (void *pvService, uint32_t function, uint32_t cParms, VBOXHGCMSVCPARM paParms[]));

    /** Inform the service about a VM save operation. */
    DECLR3CALLBACKMEMBER(int, pfnSaveState, (void *pvService, uint32_t u32ClientID, void *pvClient, PSSMHANDLE pSSM));

    /** Inform the service about a VM load operation. */
    DECLR3CALLBACKMEMBER(int, pfnLoadState, (void *pvService, uint32_t u32ClientID, void *pvClient, PSSMHANDLE pSSM));

    /** Register a service extension callback. */
    DECLR3CALLBACKMEMBER(int, pfnRegisterExtension, (void *pvService, PFNHGCMSVCEXT pfnExtension, void *pvExtension));

    /** User/instance data pointer for the service. */
    void *pvService;

    /** @} */
} VBOXHGCMSVCFNTABLE;
#pragma pack()


/** Service initialization entry point. */
typedef DECLCALLBACK(int) VBOXHGCMSVCLOAD(VBOXHGCMSVCFNTABLE *ptable);
typedef VBOXHGCMSVCLOAD *PFNVBOXHGCMSVCLOAD;
#define VBOX_HGCM_SVCLOAD_NAME "VBoxHGCMSvcLoad"

#endif