path: root/include/VBox/HostServices/GuestPropertySvc.h

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

/*
 * Copyright (C) 2006-2022 Oracle and/or its affiliates.
 *
 * This file is part of VirtualBox base platform packages, as
 * available from https://www.virtualbox.org.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, in version 3 of the
 * License.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <https://www.gnu.org/licenses>.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
 * in the VirtualBox 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.
 *
 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
 */

#ifndef VBOX_INCLUDED_HostServices_GuestPropertySvc_h
#define VBOX_INCLUDED_HostServices_GuestPropertySvc_h
#ifndef RT_WITHOUT_PRAGMA_ONCE
# pragma once
#endif

#include <VBox/VMMDevCoreTypes.h>
#include <VBox/VBoxGuestCoreTypes.h>
#include <VBox/log.h>
#include <iprt/err.h>
#include <iprt/assertcompile.h>
#include <iprt/string.h>


/** Maximum size for property names (including the terminator). */
#define GUEST_PROP_MAX_NAME_LEN             64
/** Maximum size for property values (including the terminator). */
#define GUEST_PROP_MAX_VALUE_LEN            1024
/** Maximum number of properties per guest. */
#define GUEST_PROP_MAX_PROPS                256
/** Maximum size for enumeration patterns (including the terminators). */
#define GUEST_PROP_MAX_PATTERN_LEN          1024
/** Maximum number of changes we remember for guest notifications. */
#define GUEST_PROP_MAX_GUEST_NOTIFICATIONS  256
/** Maximum number of current pending waits per client. */
#define GUEST_PROP_MAX_GUEST_CONCURRENT_WAITS 16


/** @name GUEST_PROP_F_XXX - The guest property flag values which are currently accepted.
 * @{
 */
#define GUEST_PROP_F_NILFLAG          UINT32_C(0)
/** Transient until VM gets shut down. */
#define GUEST_PROP_F_TRANSIENT        RT_BIT_32(1)
#define GUEST_PROP_F_RDONLYGUEST      RT_BIT_32(2)
#define GUEST_PROP_F_RDONLYHOST       RT_BIT_32(3)
/** Transient until VM gets a reset / restarts.
 *  Implies TRANSIENT. */
#define GUEST_PROP_F_TRANSRESET       RT_BIT_32(4)
#define GUEST_PROP_F_READONLY         (GUEST_PROP_F_RDONLYGUEST | GUEST_PROP_F_RDONLYHOST)
#define GUEST_PROP_F_ALLFLAGS         (GUEST_PROP_F_TRANSIENT | GUEST_PROP_F_READONLY | GUEST_PROP_F_TRANSRESET)
/** @} */

/**
 * Check that a string fits our criteria for a property name.
 *
 * @returns IPRT status code
 * @param   pszName   The string to check, must be valid Utf8
 * @param   cbName    The number of bytes @a pszName points to, including the
 *                    terminating character.
 */
DECLINLINE(int) GuestPropValidateName(const char *pszName, size_t cbName)
{
    /* Property name is expected to be at least 1 charecter long plus terminating character. */
    AssertReturn(cbName >= 2, VERR_INVALID_PARAMETER);
    AssertReturn(cbName <= GUEST_PROP_MAX_NAME_LEN, VERR_INVALID_PARAMETER);

    AssertPtrReturn(pszName, VERR_INVALID_POINTER);

    AssertReturn(memchr(pszName, '*', cbName) == NULL, VERR_INVALID_PARAMETER);
    AssertReturn(memchr(pszName, '?', cbName) == NULL, VERR_INVALID_PARAMETER);
    AssertReturn(memchr(pszName, '|', cbName) == NULL, VERR_INVALID_PARAMETER);

    return VINF_SUCCESS;
}

/**
 * Check a string fits our criteria for the value of a guest property.
 *
 * @returns IPRT status code
 * @retval  VINF_SUCCESS if guest property value corresponds to all criteria.
 * @retval  VERR_TOO_MUCH_DATA if guest property value size exceeds limits.
 * @retval  VERR_INVALID_PARAMETER if guest property does not correspond to all other criteria.
 * @param   pszValue  The string to check, must be valid utf-8.
 * @param   cbValue   The size of of @a pszValue in bytes, including the
 *                    terminator.
 * @thread  HGCM
 */
DECLINLINE(int) GuestPropValidateValue(const char *pszValue, size_t cbValue)
{
    AssertPtrReturn(pszValue, VERR_INVALID_POINTER);

    /* Zero-length values are possible, however buffer should contain terminating character at least. */
    AssertReturn(cbValue > 0, VERR_INVALID_PARAMETER);
    AssertReturn(cbValue <= GUEST_PROP_MAX_VALUE_LEN, VERR_TOO_MUCH_DATA);

    return VINF_SUCCESS;
}

/**
 * Get the name of a flag as a string.
 * @returns the name, or NULL if fFlag is invalid.
 * @param   fFlag       The flag, GUEST_PROP_F_XXX.
 * @param   pcchName    Where to return the name length.
 */
DECLINLINE(const char *) GuestPropFlagNameAndLen(uint32_t fFlag, size_t *pcchName)
{
    switch (fFlag)
    {
        case GUEST_PROP_F_TRANSIENT:
            *pcchName = sizeof("TRANSIENT") - 1;
            return "TRANSIENT";
        case GUEST_PROP_F_RDONLYGUEST:
            *pcchName = sizeof("RDONLYGUEST") - 1;
            return "RDONLYGUEST";
        case GUEST_PROP_F_RDONLYHOST:
            *pcchName = sizeof("RDONLYHOST") - 1;
            return "RDONLYHOST";
        case GUEST_PROP_F_READONLY:
            *pcchName = sizeof("READONLY") - 1;
            return "READONLY";
        case GUEST_PROP_F_TRANSRESET:
            *pcchName = sizeof("TRANSRESET") - 1;
            return "TRANSRESET";
        default:
            *pcchName = 0;
            return NULL;
    }
}

/**
 * Maximum length for the property flags field.  We only ever return one of
 * RDONLYGUEST, RDONLYHOST and RDONLY
 */
#define GUEST_PROP_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
 * @retval   VERR_INVALID_PARAMETER 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) GuestPropValidateFlags(const char *pcszFlags, uint32_t *pfFlags)
{
    static const uint32_t s_aFlagList[] =
    {
        GUEST_PROP_F_TRANSIENT, GUEST_PROP_F_READONLY, GUEST_PROP_F_RDONLYGUEST, GUEST_PROP_F_RDONLYHOST, GUEST_PROP_F_TRANSRESET
    };
    const char *pcszNext = pcszFlags;
    int rc = VINF_SUCCESS;
    uint32_t fFlags = 0;
    AssertLogRelReturn(RT_VALID_PTR(pfFlags), VERR_INVALID_POINTER);

    if (pcszFlags)
    {
        while (*pcszNext == ' ')
            ++pcszNext;
        while ((*pcszNext != '\0') && RT_SUCCESS(rc))
        {
            unsigned i;
            rc = VERR_PARSE_ERROR;
            for (i = 0; i < RT_ELEMENTS(s_aFlagList); ++i)
            {
                size_t      cchFlagName;
                const char *pszFlagName = GuestPropFlagNameAndLen(s_aFlagList[i], &cchFlagName);
                if (RTStrNICmpAscii(pcszNext, pszFlagName, cchFlagName) == 0)
                {
                    char ch;
                    fFlags |= s_aFlagList[i];
                    pcszNext += cchFlagName;
                    while ((ch = *pcszNext) == ' ')
                        ++pcszNext;
                    rc = VINF_SUCCESS;
                    if (ch == ',')
                    {
                        ++pcszNext;
                        while (*pcszNext == ' ')
                            ++pcszNext;
                    }
                    else if (ch != '\0')
                        rc = VERR_PARSE_ERROR;
                    break;
                }
            }
        }
    }
    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) GUEST_PROP_MAX_FLAGS_LEN.
 */
DECLINLINE(int) GuestPropWriteFlags(uint32_t fFlags, char *pszFlags)
{
    /* Putting READONLY before the other RDONLY flags keeps the result short. */
    static const uint32_t s_aFlagList[] =
    {
        GUEST_PROP_F_TRANSIENT, GUEST_PROP_F_READONLY, GUEST_PROP_F_RDONLYGUEST, GUEST_PROP_F_RDONLYHOST, GUEST_PROP_F_TRANSRESET
    };
    int rc = VINF_SUCCESS;

    AssertLogRelReturn(RT_VALID_PTR(pszFlags), VERR_INVALID_POINTER);
    if ((fFlags & ~GUEST_PROP_F_ALLFLAGS) == GUEST_PROP_F_NILFLAG)
    {
        char *pszNext;
        unsigned i;

        /* TRANSRESET implies TRANSIENT.  For compatability with old clients we
           always set TRANSIENT when TRANSRESET appears. */
        if (fFlags & GUEST_PROP_F_TRANSRESET)
            fFlags |= GUEST_PROP_F_TRANSIENT;

        pszNext = pszFlags;
        for (i = 0; i < RT_ELEMENTS(s_aFlagList); ++i)
        {
            if (s_aFlagList[i] == (fFlags & s_aFlagList[i]))
            {
                size_t      cchFlagName;
                const char *pszFlagName = GuestPropFlagNameAndLen(s_aFlagList[i], &cchFlagName);
                memcpy(pszNext, pszFlagName, cchFlagName);
                pszNext += cchFlagName;
                fFlags &= ~s_aFlagList[i];
                if (fFlags != GUEST_PROP_F_NILFLAG)
                {
                    *pszNext++ = ',';
                    *pszNext++ = ' ';
                }
            }
        }
        *pszNext = '\0';

        Assert((uintptr_t)(pszNext - pszFlags) < GUEST_PROP_MAX_FLAGS_LEN);
        Assert(fFlags == GUEST_PROP_F_NILFLAG); /* bad s_aFlagList */
    }
    else
        rc = VERR_INVALID_PARAMETER;
    return rc;
}


/** @name The service functions which are callable by host.
 * @{
 */
/** 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. */
#define GUEST_PROP_FN_HOST_SET_PROPS        1
/** Get the value attached to a guest property.
 * The parameter format matches that of GET_PROP. */
#define GUEST_PROP_FN_HOST_GET_PROP         2
/** Set the value attached to a guest property.
 * The parameter format matches that of SET_PROP. */
#define GUEST_PROP_FN_HOST_SET_PROP         3
/** Set the value attached to a guest property.
 * The parameter format matches that of SET_PROP_VALUE. */
#define GUEST_PROP_FN_HOST_SET_PROP_VALUE   4
/** Remove a guest property.
 * The parameter format matches that of DEL_PROP. */
#define GUEST_PROP_FN_HOST_DEL_PROP         5
/** Enumerate guest properties.
 * The parameter format matches that of ENUM_PROPS. */
#define GUEST_PROP_FN_HOST_ENUM_PROPS       6
/** Set global flags for the service.
 * Currently RDONLYGUEST is supported.  Takes one 32-bit unsigned integer
 * parameter for the flags. */
#define GUEST_PROP_FN_HOST_SET_GLOBAL_FLAGS 7
/** @} */


/** @name The service functions which are called by guest.
 *
 * @note The numbers may not change!
 * @{
 */
/** Get a guest property */
#define GUEST_PROP_FN_GET_PROP              1
/** Set a guest property */
#define GUEST_PROP_FN_SET_PROP              2
/** Set just the value of a guest property */
#define GUEST_PROP_FN_SET_PROP_VALUE        3
/** Delete a guest property */
#define GUEST_PROP_FN_DEL_PROP              4
/** Enumerate guest properties */
#define GUEST_PROP_FN_ENUM_PROPS            5
/** Poll for guest notifications */
#define GUEST_PROP_FN_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 GUESTPROPHOSTCALLBACKDATA
{
    /** Magic number to identify the structure (GUESTPROPHOSTCALLBACKDATA_MAGIC). */
    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;
} GUESTPROPHOSTCALLBACKDATA;
/** Poitner to a data structure to pass to the service extension callback. */
typedef GUESTPROPHOSTCALLBACKDATA *PGUESTPROPHOSTCALLBACKDATA;

/** Magic number for sanity checking the HOSTCALLBACKDATA structure */
#define GUESTPROPHOSTCALLBACKDATA_MAGIC     UINT32_C(0x69c87a78)

/**
 * HGCM parameter structures.  Packing is explicitly defined as this is a wire format.
 */
/** The guest is requesting the value of a property */
typedef struct GuestPropMsgGetProperty
{
    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;
} GuestPropMsgGetProperty;
AssertCompileSize(GuestPropMsgGetProperty, 40 + 4 * (ARCH_BITS == 64 ? 16 : 12));

/** The guest is requesting to change a property */
typedef struct GuestPropMsgSetProperty
{
    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 GUEST_PROP_MAX_FLAGS_LEN and only
     * known flag names and values will be accepted.
     */
    HGCMFunctionParameter flags;
} GuestPropMsgSetProperty;
AssertCompileSize(GuestPropMsgSetProperty, 40 + 3 * (ARCH_BITS == 64 ? 16 : 12));

/** The guest is requesting to change the value of a property */
typedef struct GuestPropMsgSetPropertyValue
{
    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;
} GuestPropMsgSetPropertyValue;
AssertCompileSize(GuestPropMsgSetPropertyValue, 40 + 2 * (ARCH_BITS == 64 ? 16 : 12));

/** The guest is requesting to remove a property */
typedef struct GuestPropMsgDelProperty
{
    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;
} GuestPropMsgDelProperty;
AssertCompileSize(GuestPropMsgDelProperty, 40 + 1 * (ARCH_BITS == 64 ? 16 : 12));

/** The guest is requesting to enumerate properties */
typedef struct GuestPropMsgEnumProperties
{
    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;
} GuestPropMsgEnumProperties;
AssertCompileSize(GuestPropMsgEnumProperties, 40 + 3 * (ARCH_BITS == 64 ? 16 : 12));

/**
 * 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 GuestPropMsgGetNotification
{
    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;
} GuestPropMsgGetNotification;
AssertCompileSize(GuestPropMsgGetNotification, 40 + 4 * (ARCH_BITS == 64 ? 16 : 12));


#endif /* !VBOX_INCLUDED_HostServices_GuestPropertySvc_h */