xnu-2782.10.72.tar.gz

[apple/xnu.git] / osfmk / ipc / ipc_table.c

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 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
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/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 */
/*
 *	File:	ipc/ipc_table.c
 *	Author:	Rich Draves
 *	Date:	1989
 *
 *	Functions to manipulate tables of IPC capabilities.
 */

#include <mach/kern_return.h>
#include <mach/vm_param.h>
#include <ipc/ipc_table.h>
#include <ipc/ipc_port.h>
#include <ipc/ipc_entry.h>
#include <kern/kalloc.h>
#include <vm/vm_kern.h>

/*
 * Forward declarations
 */
void ipc_table_fill(
	ipc_table_size_t	its,
	unsigned int		num,
	unsigned int		min,
	vm_size_t		elemsize);

/*
 *	We borrow the kalloc map, rather than creating
 *	yet another submap of the kernel map.
 */

extern vm_map_t kalloc_map;

ipc_table_size_t ipc_table_entries;
unsigned int ipc_table_entries_size = 512;

ipc_table_size_t ipc_table_requests;
unsigned int ipc_table_requests_size = 64;

void
ipc_table_fill(
	ipc_table_size_t	its,	     /* array to fill */
	unsigned int		num,	     /* size of array */
	unsigned int		min,	     /* at least this many elements */
	vm_size_t		elemsize)    /* size of elements */
{
	unsigned int index;
	vm_size_t minsize = min * elemsize;
	vm_size_t size;
	vm_size_t incrsize;

	/* first use powers of two, up to the page size */

	for (index = 0, size = 1;
	     (index < num) && (size < PAGE_SIZE);
	     size <<= 1) {
		if (size >= minsize) {
			its[index].its_size = (ipc_table_elems_t)(size / elemsize);
			index++;
		}
	}

	/* then increments of a page, then two pages, etc. */

	for (incrsize = PAGE_SIZE; index < num;) {
		unsigned int period;

		for (period = 0;
		     (period < 15) && (index < num);
		     period++, size += incrsize) {
			if (size >= minsize) {
				its[index].its_size = (ipc_table_elems_t)(size / elemsize);
				index++;
			}
		}
		if (incrsize < (vm_size_t)(PAGE_SIZE << 3))
			incrsize <<= 1;
	}
}

void
ipc_table_init(void)
{
	ipc_table_entries = (ipc_table_size_t)
		kalloc(sizeof(struct ipc_table_size) *
		       ipc_table_entries_size);
	assert(ipc_table_entries != ITS_NULL);

	ipc_table_fill(ipc_table_entries, ipc_table_entries_size - 1,
		       16, sizeof(struct ipc_entry));

	/* the last two elements should have the same size */

	ipc_table_entries[ipc_table_entries_size - 1].its_size =
		ipc_table_entries[ipc_table_entries_size - 2].its_size;


	ipc_table_requests = (ipc_table_size_t)
		kalloc(sizeof(struct ipc_table_size) *
		       ipc_table_requests_size);
	assert(ipc_table_requests != ITS_NULL);

	ipc_table_fill(ipc_table_requests, ipc_table_requests_size - 1,
		       2, sizeof(struct ipc_port_request));

	/* the last element should have zero size */

	ipc_table_requests[ipc_table_requests_size - 1].its_size = 0;
}

/*
 *	Routine:	ipc_table_alloc
 *	Purpose:
 *		Allocate a table.
 *	Conditions:
 *		May block.
 */

void *
ipc_table_alloc(
	vm_size_t	size)
{
	vm_offset_t table;

	if (size < PAGE_SIZE)
		return kalloc(size);

	if (kmem_alloc(kalloc_map, &table, size) != KERN_SUCCESS)
		table = 0;

	return (void *)table;
}


/*
 *	Routine:	ipc_table_free
 *	Purpose:
 *		Free a table allocated with ipc_table_alloc or
 *		ipc_table_realloc.
 *	Conditions:
 *		May block.
 */

void
ipc_table_free(
	vm_size_t	size,
	void *		table)
{
	if (size < PAGE_SIZE)
		kfree(table, size);
	else
		kmem_free(kalloc_map, (vm_offset_t)table, size);
}