/** @file * IPRT - Handle Tables. */ /* * Copyright (C) 2008-2020 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 IPRT_INCLUDED_handletable_h #define IPRT_INCLUDED_handletable_h #ifndef RT_WITHOUT_PRAGMA_ONCE # pragma once #endif #include #include RT_C_DECLS_BEGIN /** @defgroup grp_rt_handletable RTHandleTable - Handle Tables * @ingroup grp_rt * @{ */ /** * Callback for retaining an object during the lookup and free calls. * * This callback is executed when a handle is being looked up in one * way or another from behind the handle table lock. This allows you * to increase the reference (or some equivalent thing) during the * handle lookup and thereby eliminate any race with anyone trying * to free the handle. * * Note that there is no counterpart to this callback, so if you make * use of this you'll have to release the object manually of course. * * Another use of this callback is to do some extra access checking. * Use the return code to indicate whether the lookup should fail * or not (no object is returned on faliure, naturally). * * @returns IPRT status code for the lookup (the caller won't see this). * * @param hHandleTable The handle table handle. * @param pvObj The object which has been looked up. * @param pvCtx The context argument if the handle table was created with the * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL. * @param pvUser The user context argument specified when creating the table. */ typedef DECLCALLBACKTYPE(int, FNRTHANDLETABLERETAIN,(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, void *pvUser)); /** Pointer to a FNHANDLETABLERETAIN. */ typedef FNRTHANDLETABLERETAIN *PFNRTHANDLETABLERETAIN; /** * Callback for deleting a left over object during RTHandleTableDestroy. * * @param hHandleTable The handle table handle. * @param h The handle. * @param pvObj The object. * @param pvCtx The context argument if the handle table was created with the * RTHANDLETABLE_FLAGS_CONTEXT set. Otherwise NULL. * @param pvUser The user context argument specified when creating the table. * */ typedef DECLCALLBACKTYPE(void, FNRTHANDLETABLEDELETE,(RTHANDLETABLE hHandleTable, uint32_t h, void *pvObj, void *pvCtx, void *pvUser)); /** Pointer to a FNRTHANDLETABLEDELETE. */ typedef FNRTHANDLETABLEDELETE *PFNRTHANDLETABLEDELETE; /** @name RTHandleTableCreateEx flags * @{ */ /** Whether the handle table entries takes a context or not. * * This can be useful for associating a handle with for instance a process or * similar in order to prevent anyone but the owner from using the handle. * * Setting this means you will have to use the WithCtx functions to do the * handle management. */ #define RTHANDLETABLE_FLAGS_CONTEXT RT_BIT_32(0) /** Whether the handle table should take care of the serialization (IRQ unsafe). * If not specified the caller will have to take care of that. */ #define RTHANDLETABLE_FLAGS_LOCKED RT_BIT_32(1) /** Like RTHANDLETABLE_FLAGS_LOCKED, except it's IRQ safe. * A side-effect is that callbacks may be called with IRQs disabled. */ #define RTHANDLETABLE_FLAGS_LOCKED_IRQ_SAFE RT_BIT_32(2) /** The mask of valid flags. */ #define RTHANDLETABLE_FLAGS_MASK UINT32_C(0x00000007) /** @} */ /** * Creates a handle table. * * The handle table translates a 32-bit handle into an object pointer, * optionally calling you back so you can retain the object without * racing RTHandleTableFree. * * @returns IPRT status code and on success a handle table handle will be stored at the * location phHandleTable points at. * * @param phHandleTable Where to store the handle table handle on success. * @param fFlags Flags, see RTHANDLETABLE_FLAGS_*. * @param uBase The handle base value. This is the value of the * first handle to be returned. * @param cMax The max number of handles. When exceeded the RTHandleTableAlloc * or RTHandleTableAllocWithCtx calls will fail. Note that this * number will be rounded up to a multiple of the sub-table size, * or if it's too close to UINT32_MAX it will be rounded down. * @param pfnRetain Optional retain callback that will be called from behind the * lock (if any) during lookup. * @param pvUser The user argument to the retain callback. */ RTDECL(int) RTHandleTableCreateEx(PRTHANDLETABLE phHandleTable, uint32_t fFlags, uint32_t uBase, uint32_t cMax, PFNRTHANDLETABLERETAIN pfnRetain, void *pvUser); /** * A simplified version of the RTHandleTableCreateEx API. * * It assumes a max of about 64K handles with 1 being the base. The table * access will serialized (RTHANDLETABLE_FLAGS_LOCKED). * * @returns IPRT status code and *phHandleTable. * * @param phHandleTable Where to store the handle table handle on success. */ RTDECL(int) RTHandleTableCreate(PRTHANDLETABLE phHandleTable); /** * Destroys a handle table. * * If any entries are still in used the pfnDelete callback will be invoked * on each of them (if specfied) to allow to you clean things up. * * @returns IPRT status code * * @param hHandleTable The handle to the handle table. * @param pfnDelete Function to be called back on each handle still in use. Optional. * @param pvUser The user argument to pfnDelete. */ RTDECL(int) RTHandleTableDestroy(RTHANDLETABLE hHandleTable, PFNRTHANDLETABLEDELETE pfnDelete, void *pvUser); /** * Allocates a handle from the handle table. * * @returns IPRT status code, almost any. * @retval VINF_SUCCESS on success. * @retval VERR_NO_MEMORY if we failed to extend the handle table. * @retval VERR_NO_MORE_HANDLES if we're out of handles. * * @param hHandleTable The handle to the handle table. * @param pvObj The object to associate with the new handle. * This must be aligned on a 4 byte boundary. * @param ph Where to return the handle on success. * * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation. */ RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void *pvObj, uint32_t *ph); /** * Looks up a handle. * * @returns The object pointer on success. NULL on failure. * * @param hHandleTable The handle to the handle table. * @param h The handle to lookup. * * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation. */ RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h); /** * Looks up and frees a handle. * * @returns The object pointer on success. NULL on failure. * * @param hHandleTable The handle to the handle table. * @param h The handle to lookup. * * @remarks Do not call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation. */ RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h); /** * Allocates a handle from the handle table. * * @returns IPRT status code, almost any. * @retval VINF_SUCCESS on success. * @retval VERR_NO_MEMORY if we failed to extend the handle table. * @retval VERR_NO_MORE_HANDLES if we're out of handles. * * @param hHandleTable The handle to the handle table. * @param pvObj The object to associate with the new handle. * This must be aligned on a 4 byte boundary. * @param pvCtx The context to associate with the new handle. * @param ph Where to return the handle on success. * * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation. */ RTDECL(int) RTHandleTableAllocWithCtx(RTHANDLETABLE hHandleTable, void *pvObj, void *pvCtx, uint32_t *ph); /** * Looks up a handle. * * @returns The object pointer on success. NULL on failure. * * @param hHandleTable The handle to the handle table. * @param h The handle to lookup. * @param pvCtx The handle context, this must match what was given on allocation. * * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation. */ RTDECL(void *) RTHandleTableLookupWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx); /** * Looks up and frees a handle. * * @returns The object pointer on success. NULL on failure. * * @param hHandleTable The handle to the handle table. * @param h The handle to lookup. * @param pvCtx The handle context, this must match what was given on allocation. * * @remarks Call this if RTHANDLETABLE_FLAGS_CONTEXT was used during creation. */ RTDECL(void *) RTHandleTableFreeWithCtx(RTHANDLETABLE hHandleTable, uint32_t h, void *pvCtx); /** @} */ RT_C_DECLS_END #endif /* !IPRT_INCLUDED_handletable_h */