mem.c

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	if ((ctx->flags & ISC_MEMFLAG_INTERNAL) != 0) {
		MCTXLOCK(ctx, &ctx->lock);
		si = isc__mem_allocateunlocked(ctx, size);
	} else {
		si = isc__mem_allocateunlocked(ctx, size);
		MCTXLOCK(ctx, &ctx->lock);
		if (si != NULL)
			mem_getstats(ctx, si[-1].u.size);
	}

#if ISC_MEM_TRACKLINES
	ADD_TRACE(ctx, si, si[-1].u.size, file, line);
#endif
	if (ctx->hi_water != 0U && !ctx->hi_called &&
	    ctx->inuse > ctx->hi_water) {
		ctx->hi_called = ISC_TRUE;
		call_water = ISC_TRUE;
	}
	if (ctx->inuse > ctx->maxinuse) {
		ctx->maxinuse = ctx->inuse;
		if (ctx->hi_water != 0U && ctx->inuse > ctx->hi_water &&
		    (isc_mem_debugging & ISC_MEM_DEBUGUSAGE) != 0)
			fprintf(stderr, "maxinuse = %lu\n",
				(unsigned long)ctx->inuse);
	}
	MCTXUNLOCK(ctx, &ctx->lock);

	if (call_water)
		(ctx->water)(ctx->water_arg, ISC_MEM_HIWATER);

	return (si);
}

void
isc__mem_free(isc_mem_t *ctx, void *ptr FLARG) {
	size_info *si;
	size_t size;
	isc_boolean_t call_water= ISC_FALSE;

	REQUIRE(VALID_CONTEXT(ctx));
	REQUIRE(ptr != NULL);

	if ((isc_mem_debugging & ISC_MEM_DEBUGCTX) != 0) {
		si = &(((size_info *)ptr)[-2]);
		REQUIRE(si->u.ctx == ctx);
		size = si[1].u.size;
	} else {
		si = &(((size_info *)ptr)[-1]);
		size = si->u.size;
	}

	if ((ctx->flags & ISC_MEMFLAG_INTERNAL) != 0) {
		MCTXLOCK(ctx, &ctx->lock);
		mem_putunlocked(ctx, si, size);
	} else {
		mem_put(ctx, si, size);
		MCTXLOCK(ctx, &ctx->lock);
		mem_putstats(ctx, si, size);
	}

	DELETE_TRACE(ctx, ptr, size, file, line);

	/*
	 * The check against ctx->lo_water == 0 is for the condition
	 * when the context was pushed over hi_water but then had
	 * isc_mem_setwater() called with 0 for hi_water and lo_water.
	 */
	if (ctx->hi_called && 
	    (ctx->inuse < ctx->lo_water || ctx->lo_water == 0U)) {
		ctx->hi_called = ISC_FALSE;

		if (ctx->water != NULL)
			call_water = ISC_TRUE;
	}
	MCTXUNLOCK(ctx, &ctx->lock);

	if (call_water)
		(ctx->water)(ctx->water_arg, ISC_MEM_LOWATER);
}


/*
 * Other useful things.
 */

char *
isc__mem_strdup(isc_mem_t *mctx, const char *s FLARG) {
	size_t len;
	char *ns;

	REQUIRE(VALID_CONTEXT(mctx));
	REQUIRE(s != NULL);

	len = strlen(s);

	ns = isc__mem_allocate(mctx, len + 1 FLARG_PASS);

	if (ns != NULL)
		strncpy(ns, s, len + 1);

	return (ns);
}

void
isc_mem_setdestroycheck(isc_mem_t *ctx, isc_boolean_t flag) {
	REQUIRE(VALID_CONTEXT(ctx));
	MCTXLOCK(ctx, &ctx->lock);

	ctx->checkfree = flag;

	MCTXUNLOCK(ctx, &ctx->lock);
}

/*
 * Quotas
 */

void
isc_mem_setquota(isc_mem_t *ctx, size_t quota) {
	REQUIRE(VALID_CONTEXT(ctx));
	MCTXLOCK(ctx, &ctx->lock);

	ctx->quota = quota;

	MCTXUNLOCK(ctx, &ctx->lock);
}

size_t
isc_mem_getquota(isc_mem_t *ctx) {
	size_t quota;

	REQUIRE(VALID_CONTEXT(ctx));
	MCTXLOCK(ctx, &ctx->lock);

	quota = ctx->quota;

	MCTXUNLOCK(ctx, &ctx->lock);

	return (quota);
}

size_t
isc_mem_inuse(isc_mem_t *ctx) {
	size_t inuse;

	REQUIRE(VALID_CONTEXT(ctx));
	MCTXLOCK(ctx, &ctx->lock);

	inuse = ctx->inuse;

	MCTXUNLOCK(ctx, &ctx->lock);

	return (inuse);
}

void
isc_mem_setwater(isc_mem_t *ctx, isc_mem_water_t water, void *water_arg,
                 size_t hiwater, size_t lowater)
{
	isc_boolean_t callwater = ISC_FALSE;
	isc_mem_water_t oldwater;
	void *oldwater_arg;

	REQUIRE(VALID_CONTEXT(ctx));
	REQUIRE(hiwater >= lowater);

	MCTXLOCK(ctx, &ctx->lock);
	oldwater = ctx->water;
	oldwater_arg = ctx->water_arg;
	if (water == NULL) {
		callwater = ctx->hi_called;
		ctx->water = NULL;
		ctx->water_arg = NULL;
		ctx->hi_water = 0;
		ctx->lo_water = 0;
		ctx->hi_called = ISC_FALSE;
	} else {
		if (ctx->hi_called &&
		    (ctx->water != water || ctx->water_arg != water_arg ||
		     ctx->inuse < lowater || lowater == 0U))
			callwater = ISC_TRUE;
		ctx->water = water;
		ctx->water_arg = water_arg;
		ctx->hi_water = hiwater;
		ctx->lo_water = lowater;
		ctx->hi_called = ISC_FALSE;
	}
	MCTXUNLOCK(ctx, &ctx->lock);
	
	if (callwater && oldwater != NULL)
		(oldwater)(oldwater_arg, ISC_MEM_LOWATER);
}

/*
 * Memory pool stuff
 */

isc_result_t
isc_mempool_create(isc_mem_t *mctx, size_t size, isc_mempool_t **mpctxp) {
	isc_mempool_t *mpctx;

	REQUIRE(VALID_CONTEXT(mctx));
	REQUIRE(size > 0U);
	REQUIRE(mpctxp != NULL && *mpctxp == NULL);

	/*
	 * Allocate space for this pool, initialize values, and if all works
	 * well, attach to the memory context.
	 */
	mpctx = isc_mem_get(mctx, sizeof(isc_mempool_t));
	if (mpctx == NULL)
		return (ISC_R_NOMEMORY);

	mpctx->magic = MEMPOOL_MAGIC;
	mpctx->lock = NULL;
	mpctx->mctx = mctx;
	mpctx->size = size;
	mpctx->maxalloc = UINT_MAX;
	mpctx->allocated = 0;
	mpctx->freecount = 0;
	mpctx->freemax = 1;
	mpctx->fillcount = 1;
	mpctx->gets = 0;
#if ISC_MEMPOOL_NAMES
	mpctx->name[0] = 0;
#endif
	mpctx->items = NULL;

	*mpctxp = mpctx;

	MCTXLOCK(mctx, &mctx->lock);
	ISC_LIST_INITANDAPPEND(mctx->pools, mpctx, link);
	MCTXUNLOCK(mctx, &mctx->lock);

	return (ISC_R_SUCCESS);
}

void
isc_mempool_setname(isc_mempool_t *mpctx, const char *name) {
	REQUIRE(name != NULL);

#if ISC_MEMPOOL_NAMES
	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	strncpy(mpctx->name, name, sizeof(mpctx->name) - 1);
	mpctx->name[sizeof(mpctx->name) - 1] = '\0';

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);
#else
	UNUSED(mpctx);
	UNUSED(name);
#endif
}

void
isc_mempool_destroy(isc_mempool_t **mpctxp) {
	isc_mempool_t *mpctx;
	isc_mem_t *mctx;
	isc_mutex_t *lock;
	element *item;

	REQUIRE(mpctxp != NULL);
	mpctx = *mpctxp;
	REQUIRE(VALID_MEMPOOL(mpctx));
#if ISC_MEMPOOL_NAMES
	if (mpctx->allocated > 0)
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_mempool_destroy(): mempool %s "
				 "leaked memory",
				 mpctx->name);
#endif
	REQUIRE(mpctx->allocated == 0);

	mctx = mpctx->mctx;

	lock = mpctx->lock;

	if (lock != NULL)
		LOCK(lock);

	/*
	 * Return any items on the free list
	 */
	MCTXLOCK(mctx, &mctx->lock);
	while (mpctx->items != NULL) {
		INSIST(mpctx->freecount > 0);
		mpctx->freecount--;
		item = mpctx->items;
		mpctx->items = item->next;

		if ((mctx->flags & ISC_MEMFLAG_INTERNAL) != 0) {
			mem_putunlocked(mctx, item, mpctx->size);
		} else {
			mem_put(mctx, item, mpctx->size);
			mem_putstats(mctx, item, mpctx->size);
		}
	}
	MCTXUNLOCK(mctx, &mctx->lock);

	/*
	 * Remove our linked list entry from the memory context.
	 */
	MCTXLOCK(mctx, &mctx->lock);
	ISC_LIST_UNLINK(mctx->pools, mpctx, link);
	MCTXUNLOCK(mctx, &mctx->lock);

	mpctx->magic = 0;

	isc_mem_put(mpctx->mctx, mpctx, sizeof(isc_mempool_t));

	if (lock != NULL)
		UNLOCK(lock);

	*mpctxp = NULL;
}

void
isc_mempool_associatelock(isc_mempool_t *mpctx, isc_mutex_t *lock) {
	REQUIRE(VALID_MEMPOOL(mpctx));
	REQUIRE(mpctx->lock == NULL);
	REQUIRE(lock != NULL);

	mpctx->lock = lock;
}

void *
isc__mempool_get(isc_mempool_t *mpctx FLARG) {
	element *item;
	isc_mem_t *mctx;
	unsigned int i;

	REQUIRE(VALID_MEMPOOL(mpctx));

	mctx = mpctx->mctx;

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	/*
	 * Don't let the caller go over quota
	 */
	if (mpctx->allocated >= mpctx->maxalloc) {
		item = NULL;
		goto out;
	}

	/*
	 * if we have a free list item, return the first here
	 */
	item = mpctx->items;
	if (item != NULL) {
		mpctx->items = item->next;
		INSIST(mpctx->freecount > 0);
		mpctx->freecount--;
		mpctx->gets++;
		mpctx->allocated++;
		goto out;
	}

	/*
	 * We need to dip into the well.  Lock the memory context here and
	 * fill up our free list.
	 */
	MCTXLOCK(mctx, &mctx->lock);
	for (i = 0; i < mpctx->fillcount; i++) {
		if ((mctx->flags & ISC_MEMFLAG_INTERNAL) != 0) {
			item = mem_getunlocked(mctx, mpctx->size);
		} else {
			item = mem_get(mctx, mpctx->size);
			if (item != NULL)
				mem_getstats(mctx, mpctx->size);
		}
		if (item == NULL)
			break;
		item->next = mpctx->items;
		mpctx->items = item;
		mpctx->freecount++;
	}
	MCTXUNLOCK(mctx, &mctx->lock);

	/*
	 * If we didn't get any items, return NULL.
	 */
	item = mpctx->items;
	if (item == NULL)
		goto out;

	mpctx->items = item->next;
	mpctx->freecount--;
	mpctx->gets++;
	mpctx->allocated++;

 out:
	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);

#if ISC_MEM_TRACKLINES
	if (item != NULL) {
		MCTXLOCK(mctx, &mctx->lock);
		ADD_TRACE(mctx, item, mpctx->size, file, line);
		MCTXUNLOCK(mctx, &mctx->lock);
	}
#endif /* ISC_MEM_TRACKLINES */

	return (item);
}

void
isc__mempool_put(isc_mempool_t *mpctx, void *mem FLARG) {
	isc_mem_t *mctx;
	element *item;

	REQUIRE(VALID_MEMPOOL(mpctx));
	REQUIRE(mem != NULL);

	mctx = mpctx->mctx;

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	INSIST(mpctx->allocated > 0);
	mpctx->allocated--;

#if ISC_MEM_TRACKLINES
	MCTXLOCK(mctx, &mctx->lock);
	DELETE_TRACE(mctx, mem, mpctx->size, file, line);
	MCTXUNLOCK(mctx, &mctx->lock);
#endif /* ISC_MEM_TRACKLINES */

	/*
	 * If our free list is full, return this to the mctx directly.
	 */
	if (mpctx->freecount >= mpctx->freemax) {
		if ((mctx->flags & ISC_MEMFLAG_INTERNAL) != 0) {
			MCTXLOCK(mctx, &mctx->lock);
			mem_putunlocked(mctx, mem, mpctx->size);
			MCTXUNLOCK(mctx, &mctx->lock);
		} else {
			mem_put(mctx, mem, mpctx->size);
			MCTXLOCK(mctx, &mctx->lock);
			mem_putstats(mctx, mem, mpctx->size);
			MCTXUNLOCK(mctx, &mctx->lock);
		}
		if (mpctx->lock != NULL)
			UNLOCK(mpctx->lock);
		return;
	}

	/*
	 * Otherwise, attach it to our free list and bump the counter.
	 */
	mpctx->freecount++;
	item = (element *)mem;
	item->next = mpctx->items;
	mpctx->items = item;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);
}

/*
 * Quotas
 */

void
isc_mempool_setfreemax(isc_mempool_t *mpctx, unsigned int limit) {
	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	mpctx->freemax = limit;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);
}

unsigned int
isc_mempool_getfreemax(isc_mempool_t *mpctx) {
	unsigned int freemax;

	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	freemax = mpctx->freemax;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);

	return (freemax);
}

unsigned int
isc_mempool_getfreecount(isc_mempool_t *mpctx) {
	unsigned int freecount;

	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	freecount = mpctx->freecount;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);

	return (freecount);
}

void
isc_mempool_setmaxalloc(isc_mempool_t *mpctx, unsigned int limit) {
	REQUIRE(limit > 0);

	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	mpctx->maxalloc = limit;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);
}

unsigned int
isc_mempool_getmaxalloc(isc_mempool_t *mpctx) {
	unsigned int maxalloc;

	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	maxalloc = mpctx->maxalloc;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);

	return (maxalloc);
}

unsigned int
isc_mempool_getallocated(isc_mempool_t *mpctx) {
	unsigned int allocated;

	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	allocated = mpctx->allocated;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);

	return (allocated);
}

void
isc_mempool_setfillcount(isc_mempool_t *mpctx, unsigned int limit) {
	REQUIRE(limit > 0);
	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	mpctx->fillcount = limit;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);
}

unsigned int
isc_mempool_getfillcount(isc_mempool_t *mpctx) {
	unsigned int fillcount;

	REQUIRE(VALID_MEMPOOL(mpctx));

	if (mpctx->lock != NULL)
		LOCK(mpctx->lock);

	fillcount = mpctx->fillcount;

	if (mpctx->lock != NULL)
		UNLOCK(mpctx->lock);

	return (fillcount);
}

void
isc_mem_printactive(isc_mem_t *ctx, FILE *file) {

	REQUIRE(VALID_CONTEXT(ctx));
	REQUIRE(file != NULL);

#if !ISC_MEM_TRACKLINES
	UNUSED(ctx);
	UNUSED(file);
#else
	print_active(ctx, file);
#endif
}

void
isc_mem_printallactive(FILE *file) {
#if !ISC_MEM_TRACKLINES
	UNUSED(file);
#else
	isc_mem_t *ctx;

	RUNTIME_CHECK(isc_once_do(&once, initialize_action) == ISC_R_SUCCESS);

	LOCK(&lock);
	for (ctx = ISC_LIST_HEAD(contexts);
	     ctx != NULL;
	     ctx = ISC_LIST_NEXT(ctx, link)) {
		fprintf(file, "context: %p\n", ctx);
		print_active(ctx, file);
	}
	UNLOCK(&lock);
#endif
}

void    
isc_mem_checkdestroyed(FILE *file) {

	RUNTIME_CHECK(isc_once_do(&once, initialize_action) == ISC_R_SUCCESS);

	LOCK(&lock);
	if (!ISC_LIST_EMPTY(contexts))  {
#if ISC_MEM_TRACKLINES
		isc_mem_t *ctx;

		for (ctx = ISC_LIST_HEAD(contexts);
		     ctx != NULL;
		     ctx = ISC_LIST_NEXT(ctx, link)) {
			fprintf(file, "context: %p\n", ctx);
			print_active(ctx, file);
		}
		fflush(file);
#endif
		INSIST(1);
	}
	UNLOCK(&lock);
}