source: vbox/trunk/include/VBox/HostServices/GuestPropertySvc.h@ 68667

/** @file
 * Guest property service:
 * Common header for host service and guest clients.
 */

/*
 * 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_HostService_GuestPropertyService_h
#define ___VBox_HostService_GuestPropertyService_h

#include <VBox/VMMDevCoreTypes.h>
#include <VBox/VBoxGuestCoreTypes.h>
#include <VBox/log.h>
#include <VBox/hgcmsvc.h>
#include <iprt/assert.h>
#include <iprt/string.h>

/** Everything defined in this file lives in this namespace. */
namespace guestProp {

/******************************************************************************
* Typedefs, constants and inlines                                             *
******************************************************************************/

/** Maximum length for property names */
enum { MAX_NAME_LEN = 64 };
/** Maximum length for property values */
enum { MAX_VALUE_LEN = 128 };
/** Maximum number of properties per guest */
enum { MAX_PROPS = 256 };
/** Maximum size for enumeration patterns */
enum { MAX_PATTERN_LEN = 1024 };
/** Maximum number of changes we remember for guest notifications */
enum { MAX_GUEST_NOTIFICATIONS = 256 };

/**
 * The guest property flag values which are currently accepted.
 */
enum ePropFlags
{
    NILFLAG          = 0,
    /** Transient until VM gets shut down. */
    TRANSIENT        = RT_BIT(1),
    RDONLYGUEST      = RT_BIT(2),
    RDONLYHOST       = RT_BIT(3),
    /** Transient until VM gets a reset / restarts.
     *  Implies TRANSIENT. */
    TRANSRESET       = RT_BIT(4),
    READONLY         = RDONLYGUEST | RDONLYHOST,
    ALLFLAGS         = TRANSIENT | READONLY | TRANSRESET
};

/**
 * Get the name of a flag as a string.
 * @returns the name, or NULL if fFlag is invalid.
 * @param   fFlag  the flag.  Must be a value from the ePropFlags enumeration
 *                 list.
 */
DECLINLINE(const char *) flagName(uint32_t fFlag)
{
    switch (fFlag)
    {
        case TRANSIENT:
            return "TRANSIENT";
        case RDONLYGUEST:
            return "RDONLYGUEST";
        case RDONLYHOST:
            return "RDONLYHOST";
        case READONLY:
            return "READONLY";
        case TRANSRESET:
            return "TRANSRESET";
        default:
            break;
    }
    return NULL;
}

/**
 * Get the length of a flag name as returned by flagName.
 * @returns the length, or 0 if fFlag is invalid.
 * @param   fFlag  the flag.  Must be a value from the ePropFlags enumeration
 *                 list.
 */
DECLINLINE(size_t) flagNameLen(uint32_t fFlag)
{
    const char *pcszName = flagName(fFlag);
    return RT_LIKELY(pcszName != NULL) ? strlen(pcszName) : 0;
}

/**
 * Maximum length for the property flags field.  We only ever return one of
 * RDONLYGUEST, RDONLYHOST and RDONLY
 */
enum { MAX_FLAGS_LEN = sizeof("TRANSIENT, RDONLYGUEST, TRANSRESET") };

/**
 * Parse a guest properties flags string for flag names and make sure that
 * there is no junk text in the string.
 * @returns  IPRT status code
 * @returns  VERR_INVALID_PARAM if the flag string is not valid
 * @param    pcszFlags  the flag string to parse
 * @param    pfFlags    where to store the parse result.  May not be NULL.
 * @note     This function is also inline because it must be accessible from
 *           several modules and it does not seem reasonable to put it into
 *           its own library.
 */
DECLINLINE(int) validateFlags(const char *pcszFlags, uint32_t *pfFlags)
{
    static const uint32_t s_aFlagList[] =
    {
        TRANSIENT, READONLY, RDONLYGUEST, RDONLYHOST, TRANSRESET
    };
    const char *pcszNext = pcszFlags;
    int rc = VINF_SUCCESS;
    uint32_t fFlags = 0;
    AssertLogRelReturn(VALID_PTR(pfFlags), VERR_INVALID_POINTER);

    if (pcszFlags)
    {
        while (' ' == *pcszNext)
            ++pcszNext;
        while ((*pcszNext != '\0') && RT_SUCCESS(rc))
        {
            unsigned i = 0;
            for (; i < RT_ELEMENTS(s_aFlagList); ++i)
                if (RTStrNICmp(pcszNext, flagName(s_aFlagList[i]),
                               flagNameLen(s_aFlagList[i])) == 0)
                    break;
            if (RT_ELEMENTS(s_aFlagList) == i)
                rc = VERR_PARSE_ERROR;
            else
            {
                fFlags |= s_aFlagList[i];
                pcszNext += flagNameLen(s_aFlagList[i]);
                while (' ' == *pcszNext)
                    ++pcszNext;
                if (',' == *pcszNext)
                    ++pcszNext;
                else if (*pcszNext != '\0')
                    rc = VERR_PARSE_ERROR;
                while (' ' == *pcszNext)
                    ++pcszNext;
            }
        }
    }
    if (RT_SUCCESS(rc))
        *pfFlags = fFlags;
    return rc;
}

/**
 * Write out flags to a string.
 * @returns  IPRT status code
 * @param    fFlags    the flags to write out
 * @param    pszFlags  where to write the flags string.  This must point to
 *                     a buffer of size (at least) MAX_FLAGS_LEN.
 */
DECLINLINE(int) writeFlags(uint32_t fFlags, char *pszFlags)
{
    /* Putting READONLY before the other RDONLY flags keeps the result short. */
    static const uint32_t s_aFlagList[] =
    {
        TRANSIENT, READONLY, RDONLYGUEST, RDONLYHOST, TRANSRESET
    };
    int rc = VINF_SUCCESS;

    AssertLogRelReturn(VALID_PTR(pszFlags), VERR_INVALID_POINTER);
    if ((fFlags & ~ALLFLAGS) == NILFLAG)
    {
        /* TRANSRESET implies TRANSIENT.  For compatability with old clients we
           always set TRANSIENT when TRANSRESET appears. */
        if (fFlags & TRANSRESET)
            fFlags |= TRANSIENT;

        char *pszNext = pszFlags;
        for (unsigned i = 0; i < RT_ELEMENTS(s_aFlagList); ++i)
        {
            if (s_aFlagList[i] == (fFlags & s_aFlagList[i]))
            {
                strcpy(pszNext, flagName(s_aFlagList[i]));
                pszNext += flagNameLen(s_aFlagList[i]);
                fFlags &= ~s_aFlagList[i];
                if (fFlags != NILFLAG)
                {
                    strcpy(pszNext, ", ");
                    pszNext += 2;
                }
            }
        }
        *pszNext = '\0';

        Assert(fFlags == NILFLAG); /* bad s_aFlagList */
    }
    else
        rc = VERR_INVALID_PARAMETER;
    return rc;
}

/**
 * The service functions which are callable by host.
 */
enum eHostFn
{
    /**
     * Set properties in a block.  The parameters are pointers to
     * NULL-terminated arrays containing the parameters.  These are, in order,
     * name, value, timestamp, flags.  Strings are stored as pointers to
     * mutable utf8 data.  All parameters must be supplied.
     */
    SET_PROPS_HOST = 1,
    /**
     * Get the value attached to a guest property
     * The parameter format matches that of GET_PROP.
     */
    GET_PROP_HOST = 2,
    /**
     * Set the value attached to a guest property
     * The parameter format matches that of SET_PROP.
     */
    SET_PROP_HOST = 3,
    /**
     * Set the value attached to a guest property
     * The parameter format matches that of SET_PROP_VALUE.
     */
    SET_PROP_VALUE_HOST = 4,
    /**
     * Remove a guest property.
     * The parameter format matches that of DEL_PROP.
     */
    DEL_PROP_HOST = 5,
    /**
     * Enumerate guest properties.
     * The parameter format matches that of ENUM_PROPS.
     */
    ENUM_PROPS_HOST = 6,

    /**
     * Set global flags for the service.  Currently RDONLYGUEST is supported.
     * Takes one 32-bit unsigned integer parameter for the flags.
     */
    SET_GLOBAL_FLAGS_HOST = 7,

    /**
     * Return the pointer to a debug info function enumerating all guest properties.
     */
    GET_DBGF_INFO_FN = 8
};

/**
 * The service functions which are called by guest.  The numbers may not change,
 * so we hardcode them.
 */
enum eGuestFn
{
    /** Get a guest property */
    GET_PROP = 1,
    /** Set a guest property */
    SET_PROP = 2,
    /** Set just the value of a guest property */
    SET_PROP_VALUE = 3,
    /** Delete a guest property */
    DEL_PROP = 4,
    /** Enumerate guest properties */
    ENUM_PROPS = 5,
    /** Poll for guest notifications */
    GET_NOTIFICATION = 6
};

/**
 * Data structure to pass to the service extension callback.  We use this to
 * notify the host of changes to properties.
 */
typedef struct _HOSTCALLBACKDATA
{
    /** Magic number to identify the structure */
    uint32_t u32Magic;
    /** The name of the property that was changed */
    const char *pcszName;
    /** The new property value, or NULL if the property was deleted */
    const char *pcszValue;
    /** The timestamp of the modification */
    uint64_t u64Timestamp;
    /** The flags field of the modified property */
    const char *pcszFlags;
} HOSTCALLBACKDATA, *PHOSTCALLBACKDATA;

enum
{
    /** Magic number for sanity checking the HOSTCALLBACKDATA structure */
    HOSTCALLBACKMAGIC = 0x69c87a78
};

/**
 * HGCM parameter structures.  Packing is explicitly defined as this is a wire format.
 */
#pragma pack (1)
/** The guest is requesting the value of a property */
typedef struct _GetProperty
{
    VBGLIOCHGCMCALL hdr;

    /**
     * The property name (IN pointer)
     * This must fit to a number of criteria, namely
     *  - Only Utf8 strings are allowed
     *  - Less than or equal to MAX_NAME_LEN bytes in length
     *  - Zero terminated
     */
    HGCMFunctionParameter name;

    /**
     * The returned string data will be placed here.  (OUT pointer)
     * This call returns two null-terminated strings which will be placed one
     * after another: value and flags.
     */
    HGCMFunctionParameter buffer;

    /**
     * The property timestamp.  (OUT uint64_t)
     */
    HGCMFunctionParameter timestamp;

    /**
     * If the buffer provided was large enough this will contain the size of
     * the returned data.  Otherwise it will contain the size of the buffer
     * needed to hold the data and VERR_BUFFER_OVERFLOW will be returned.
     * (OUT uint32_t)
     */
    HGCMFunctionParameter size;
} GetProperty;

/** The guest is requesting to change a property */
typedef struct _SetProperty
{
    VBGLIOCHGCMCALL hdr;

    /**
     * The property name.  (IN pointer)
     * This must fit to a number of criteria, namely
     *  - Only Utf8 strings are allowed
     *  - Less than or equal to MAX_NAME_LEN bytes in length
     *  - Zero terminated
     */
    HGCMFunctionParameter name;

    /**
     * The value of the property (IN pointer)
     * Criteria as for the name parameter, but with length less than or equal to
     * MAX_VALUE_LEN.
     */
    HGCMFunctionParameter value;

    /**
     * The property flags (IN pointer)
     * This is a comma-separated list of the format flag=value
     * The length must be less than or equal to MAX_FLAGS_LEN and only
     * known flag names and values will be accepted.
     */
    HGCMFunctionParameter flags;
} SetProperty;

/** The guest is requesting to change the value of a property */
typedef struct _SetPropertyValue
{
    VBGLIOCHGCMCALL hdr;

    /**
     * The property name.  (IN pointer)
     * This must fit to a number of criteria, namely
     *  - Only Utf8 strings are allowed
     *  - Less than or equal to MAX_NAME_LEN bytes in length
     *  - Zero terminated
     */
    HGCMFunctionParameter name;

    /**
     * The value of the property (IN pointer)
     * Criteria as for the name parameter, but with length less than or equal to
     * MAX_VALUE_LEN.
     */
    HGCMFunctionParameter value;
} SetPropertyValue;

/** The guest is requesting to remove a property */
typedef struct _DelProperty
{
    VBGLIOCHGCMCALL hdr;

    /**
     * The property name.  This must fit to a number of criteria, namely
     *  - Only Utf8 strings are allowed
     *  - Less than or equal to MAX_NAME_LEN bytes in length
     *  - Zero terminated
     */
    HGCMFunctionParameter name;
} DelProperty;

/** The guest is requesting to enumerate properties */
typedef struct _EnumProperties
{
    VBGLIOCHGCMCALL hdr;

    /**
     * Array of patterns to match the properties against, separated by '|'
     * characters.  For backwards compatibility, '\\0' is also accepted
     * as a separater.
     * (IN pointer)
     * If only a single, empty pattern is given then match all.
     */
    HGCMFunctionParameter patterns;
    /**
     * On success, null-separated array of strings in which the properties are
     * returned.  (OUT pointer)
     * The number of strings in the array is always a multiple of four,
     * and in sequences of name, value, timestamp (hexadecimal string) and the
     * flags as a comma-separated list in the format "name=value".  The list
     * is terminated by an empty string after a "flags" entry (or at the
     * start).
     */
    HGCMFunctionParameter strings;
    /**
     * On success, the size of the returned data.  If the buffer provided is
     * too small, the size of buffer needed.  (OUT uint32_t)
     */
    HGCMFunctionParameter size;
} EnumProperties;

/**
 * The guest is polling for notifications on changes to properties, specifying
 * a set of patterns to match the names of changed properties against and
 * optionally the timestamp of the last notification seen.
 * On success, VINF_SUCCESS will be returned and the buffer will contain
 * details of a property notification.  If no new notification is available
 * which matches one of the specified patterns, the call will block until one
 * is.
 * If the last notification could not be found by timestamp, VWRN_NOT_FOUND
 * will be returned and the oldest available notification will be returned.
 * If a zero timestamp is specified, the call will always wait for a new
 * notification to arrive.
 * If the buffer supplied was not large enough to hold the notification,
 * VERR_BUFFER_OVERFLOW will be returned and the size parameter will contain
 * the size of the buffer needed.
 *
 * The protocol for a guest to obtain notifications is to call
 * GET_NOTIFICATION in a loop.  On the first call, the ingoing timestamp
 * parameter should be set to zero.  On subsequent calls, it should be set to
 * the outgoing timestamp from the previous call.
 */
typedef struct _GetNotification
{
    VBGLIOCHGCMCALL hdr;

    /**
     * A list of patterns to match the guest event name against, separated by
     * vertical bars (|) (IN pointer)
     * An empty string means match all.
     */
    HGCMFunctionParameter patterns;
    /**
     * The timestamp of the last change seen (IN uint64_t)
     * This may be zero, in which case the oldest available change will be
     * sent.  If the service does not remember an event matching the
     * timestamp, then VWRN_NOT_FOUND will be returned, and the guest should
     * assume that it has missed a certain number of notifications.
     *
     * The timestamp of the change being notified of (OUT uint64_t)
     * Undefined on failure.
     */
    HGCMFunctionParameter timestamp;

    /**
     * The returned data, if any, will be placed here.  (OUT pointer)
     * This call returns three null-terminated strings which will be placed
     * one after another: name, value and flags.  For a delete notification,
     * value and flags will be empty strings.  Undefined on failure.
     */
    HGCMFunctionParameter buffer;

    /**
     * On success, the size of the returned data.  (OUT uint32_t)
     * On buffer overflow, the size of the buffer needed to hold the data.
     * Undefined on failure.
     */
    HGCMFunctionParameter size;
} GetNotification;
#pragma pack ()

} /* namespace guestProp */

#endif  /* !___VBox_HostService_GuestPropertySvc_h */