mem.h

最新的LINUX平台上的DHCP服务器|客户端|代理

/*
 * Copyright (C) 2004-2007  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1997-2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: mem.h,v 1.2 2007/11/16 11:04:11 shane Exp $ */

#ifndef ISC_MEM_H
#define ISC_MEM_H 1

/*! \file isc/mem.h */

#include <stdio.h>

#include <isc-dhcp/lang.h>
/*#include <isc-dhcp/mutex.h>*/
/*#include <isc-dhcp/platform.h>*/
#include <isc-dhcp/types.h>
/*#include <isc-dhcp/xml.h>*/
#include <isc-dhcp/result.h>

ISC_LANG_BEGINDECLS

#define ISC_MEM_LOWATER 0
#define ISC_MEM_HIWATER 1
typedef void (*isc_mem_water_t)(void *, int);

typedef void * (*isc_memalloc_t)(void *, size_t);
typedef void (*isc_memfree_t)(void *, void *);

/*%
 * Define ISC_MEM_DEBUG=1 to make all functions that free memory
 * set the pointer being freed to NULL after being freed.
 * This is the default; set ISC_MEM_DEBUG=0 to disable it.
 */
#ifndef ISC_MEM_DEBUG
#define ISC_MEM_DEBUG 1
#endif

/*%
 * Define ISC_MEM_TRACKLINES=1 to turn on detailed tracing of memory
 * allocation and freeing by file and line number.
 */
#ifndef ISC_MEM_TRACKLINES
#define ISC_MEM_TRACKLINES 1
#endif

/*%
 * Define ISC_MEM_CHECKOVERRUN=1 to turn on checks for using memory outside
 * the requested space.  This will increase the size of each allocation.
 */
#ifndef ISC_MEM_CHECKOVERRUN
#define ISC_MEM_CHECKOVERRUN 1
#endif

/*%
 * Define ISC_MEM_FILL=1 to fill each block of memory returned to the system
 * with the byte string '0xbe'.  This helps track down uninitialized pointers
 * and the like.  On freeing memory, the space is filled with '0xde' for
 * the same reasons.
 */
#ifndef ISC_MEM_FILL
#define ISC_MEM_FILL 1
#endif

/*%
 * Define ISC_MEMPOOL_NAMES=1 to make memory pools store a symbolic
 * name so that the leaking pool can be more readily identified in
 * case of a memory leak.
 */
#ifndef ISC_MEMPOOL_NAMES
#define ISC_MEMPOOL_NAMES 1
#endif

extern unsigned int isc_mem_debugging;
/*@{*/
#define ISC_MEM_DEBUGTRACE		0x00000001U
#define ISC_MEM_DEBUGRECORD		0x00000002U
#define ISC_MEM_DEBUGUSAGE		0x00000004U
#define ISC_MEM_DEBUGSIZE		0x00000008U
#define ISC_MEM_DEBUGCTX		0x00000010U
#define ISC_MEM_DEBUGALL		0x0000001FU
/*!<
 * The variable isc_mem_debugging holds a set of flags for
 * turning certain memory debugging options on or off at
 * runtime.  Its is intialized to the value ISC_MEM_DEGBUGGING,
 * which is 0 by default but may be overridden at compile time.
 * The following flags can be specified:
 *
 * \li #ISC_MEM_DEBUGTRACE
 *	Log each allocation and free to isc_lctx.
 *
 * \li #ISC_MEM_DEBUGRECORD
 *	Remember each allocation, and match them up on free.
 *	Crash if a free doesn't match an allocation.
 *
 * \li #ISC_MEM_DEBUGUSAGE
 *	If a hi_water mark is set, print the maximium inuse memory
 *	every time it is raised once it exceeds the hi_water mark.
 *
 * \li #ISC_MEM_DEBUGSIZE
 *	Check the size argument being passed to isc_mem_put() matches
 *	that passed to isc_mem_get().
 *
 * \li #ISC_MEM_DEBUGCTX
 *	Check the mctx argument being passed to isc_mem_put() matches
 *	that passed to isc_mem_get().
 */
/*@}*/

#if ISC_MEM_TRACKLINES
#define _ISC_MEM_FILELINE	, __FILE__, __LINE__
#define _ISC_MEM_FLARG		, const char *, int
#else
#define _ISC_MEM_FILELINE
#define _ISC_MEM_FLARG
#endif

/*!
 * Define ISC_MEM_USE_INTERNAL_MALLOC=1 to use the internal malloc()
 * implementation in preference to the system one.  The internal malloc()
 * is very space-efficient, and quite fast on uniprocessor systems.  It
 * performs poorly on multiprocessor machines.
 * JT: we can overcome the performance issue on multiprocessor machines
 * by carefully separating memory contexts.
 */

#ifndef ISC_MEM_USE_INTERNAL_MALLOC
#define ISC_MEM_USE_INTERNAL_MALLOC 1
#endif

/*
 * Flags for isc_mem_create2()calls.
 */
#define ISC_MEMFLAG_NOLOCK	0x00000001	 /* no lock is necessary */
#define ISC_MEMFLAG_INTERNAL	0x00000002	 /* use internal malloc */
#if ISC_MEM_USE_INTERNAL_MALLOC
#define ISC_MEMFLAG_DEFAULT 	ISC_MEMFLAG_INTERNAL
#else
#define ISC_MEMFLAG_DEFAULT 	0
#endif


#define isc_mem_get(c, s)	isc__mem_get((c), (s) _ISC_MEM_FILELINE)
#define isc_mem_allocate(c, s)	isc__mem_allocate((c), (s) _ISC_MEM_FILELINE)
#define isc_mem_strdup(c, p)	isc__mem_strdup((c), (p) _ISC_MEM_FILELINE)
#define isc_mempool_get(c)	isc__mempool_get((c) _ISC_MEM_FILELINE)

/*% 
 * isc_mem_putanddetach() is a convienence function for use where you
 * have a structure with an attached memory context.
 *
 * Given:
 *
 * \code
 * struct {
 *	...
 *	isc_mem_t *mctx;
 *	...
 * } *ptr;
 *
 * isc_mem_t *mctx;
 *
 * isc_mem_putanddetach(&ptr->mctx, ptr, sizeof(*ptr));
 * \endcode
 *
 * is the equivalent of:
 *
 * \code
 * mctx = NULL;
 * isc_mem_attach(ptr->mctx, &mctx);
 * isc_mem_detach(&ptr->mctx);
 * isc_mem_put(mctx, ptr, sizeof(*ptr));
 * isc_mem_detach(&mctx);
 * \endcode
 */

#if ISC_MEM_DEBUG
#define isc_mem_put(c, p, s) \
	do { \
		isc__mem_put((c), (p), (s) _ISC_MEM_FILELINE); \
		(p) = NULL; \
	} while (0)
#define isc_mem_putanddetach(c, p, s) \
	do { \
		isc__mem_putanddetach((c), (p), (s) _ISC_MEM_FILELINE); \
		(p) = NULL; \
	} while (0)
#define isc_mem_free(c, p) \
	do { \
		isc__mem_free((c), (p) _ISC_MEM_FILELINE); \
		(p) = NULL; \
	} while (0)
#define isc_mempool_put(c, p) \
	do { \
		isc__mempool_put((c), (p) _ISC_MEM_FILELINE); \
		(p) = NULL; \
	} while (0)
#else
#define isc_mem_put(c, p, s)	isc__mem_put((c), (p), (s) _ISC_MEM_FILELINE)
#define isc_mem_putanddetach(c, p, s) \
	isc__mem_putanddetach((c), (p), (s) _ISC_MEM_FILELINE)
#define isc_mem_free(c, p)	isc__mem_free((c), (p) _ISC_MEM_FILELINE)
#define isc_mempool_put(c, p)	isc__mempool_put((c), (p) _ISC_MEM_FILELINE)
#endif

/*@{*/
isc_result_t 
isc_mem_create(size_t max_size, size_t target_size,
	       isc_mem_t **mctxp);

isc_result_t
isc_mem_create2(size_t max_size, size_t target_size,
		isc_mem_t **mctxp, unsigned int flags);

isc_result_t 
isc_mem_createx(size_t max_size, size_t target_size,
		isc_memalloc_t memalloc, isc_memfree_t memfree,
		void *arg, isc_mem_t **mctxp);

isc_result_t 
isc_mem_createx2(size_t max_size, size_t target_size,
		 isc_memalloc_t memalloc, isc_memfree_t memfree,
		 void *arg, isc_mem_t **mctxp, unsigned int flags);

/*!<
 * \brief Create a memory context.
 *
 * 'max_size' and 'target_size' are tuning parameters.  When
 * ISC_MEMFLAG_INTERNAL is set, allocations smaller than 'max_size'
 * will be satisfied by getting blocks of size 'target_size' from the
 * system allocator and breaking them up into pieces; larger allocations
 * will use the system allocator directly. If 'max_size' and/or
 * 'target_size' are zero, default values will be * used.  When
 * ISC_MEMFLAG_INTERNAL is not set, 'target_size' is ignored.
 *
 * 'max_size' is also used to size the statistics arrays and the array
 * used to record active memory when ISC_MEM_DEBUGRECORD is set.  Settin
 * 'max_size' too low can have detrimental effects on performance.
 *
 * A memory context created using isc_mem_createx() will obtain
 * memory from the system by calling 'memalloc' and 'memfree',
 * passing them the argument 'arg'.  A memory context created
 * using isc_mem_create() will use the standard library malloc()
 * and free().
 *
 * If ISC_MEMFLAG_NOLOCK is set in 'flags', the corresponding memory context
 * will be accessed without locking.  The user who creates the context must
 * ensure there be no race.  Since this can be a source of bug, it is generally
 * inadvisable to use this flag unless the user is very sure about the race
 * condition and the access to the object is highly performance sensitive.
 *
 * Requires:
 * mctxp != NULL && *mctxp == NULL */
/*@}*/

/*@{*/
void 
isc_mem_attach(isc_mem_t *, isc_mem_t **);
void 
isc_mem_detach(isc_mem_t **);
/*!<
 * \brief Attach to / detach from a memory context.
 *
 * This is intended for applications that use multiple memory contexts