1/*
2 * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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23 * Please see the License for the specific language governing rights and
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25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*
29 * @OSF_COPYRIGHT@
30 */
31/*
32 * Mach Operating System
33 * Copyright (c) 1991,1990,1989 Carnegie Mellon University
34 * All Rights Reserved.
35 *
36 * Permission to use, copy, modify and distribute this software and its
37 * documentation is hereby granted, provided that both the copyright
38 * notice and this permission notice appear in all copies of the
39 * software, derivative works or modified versions, and any portions
40 * thereof, and that both notices appear in supporting documentation.
41 *
42 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45 *
46 * Carnegie Mellon requests users of this software to return to
47 *
48 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
49 * School of Computer Science
50 * Carnegie Mellon University
51 * Pittsburgh PA 15213-3890
52 *
53 * any improvements or extensions that they make and grant Carnegie Mellon
54 * the rights to redistribute these changes.
55 */
56/*
57 */
58/*
59 * File: ipc/ipc_entry.h
60 * Author: Rich Draves
61 * Date: 1989
62 *
63 * Definitions for translation entries, which represent
64 * tasks' capabilities for ports and port sets.
65 */
66
67#ifndef _IPC_IPC_ENTRY_H_
68#define _IPC_IPC_ENTRY_H_
69
70#include <mach/mach_types.h>
71#include <mach/port.h>
72#include <mach/kern_return.h>
73
74#include <kern/kern_types.h>
75#include <kern/zalloc.h>
76
77#include <ipc/ipc_types.h>
78
79/*
80 * Spaces hold capabilities for ipc_object_t's.
81 * Each ipc_entry_t records a capability. Most capabilities have
82 * small names, and the entries are elements of a table.
83 *
84 * The ie_index field of entries in the table implements
85 * a ordered hash table with open addressing and linear probing.
86 * This hash table converts (space, object) -> name.
87 * It is used independently of the other fields.
88 *
89 * Free (unallocated) entries in the table have null ie_object
90 * fields. The ie_bits field is zero except for IE_BITS_GEN.
91 * The ie_next (ie_request) field links free entries into a free list.
92 *
93 * The first entry in the table (index 0) is always free.
94 * It is used as the head of the free list.
95 */
96
97struct ipc_entry {
98 struct ipc_object *ie_object;
99 ipc_entry_bits_t ie_bits;
100 mach_port_index_t ie_index;
101 union {
102 mach_port_index_t next; /* next in freelist, or... */
103 ipc_table_index_t request; /* dead name request notify */
104 } index;
105};
106
107#define ie_request index.request
108#define ie_next index.next
109
110#define IE_REQ_NONE 0 /* no request */
111
112#define IE_BITS_UREFS_MASK 0x0000ffff /* 16 bits of user-reference */
113#define IE_BITS_UREFS(bits) ((bits) & IE_BITS_UREFS_MASK)
114
115#define IE_BITS_TYPE_MASK 0x001f0000 /* 5 bits of capability type */
116#define IE_BITS_TYPE(bits) ((bits) & IE_BITS_TYPE_MASK)
117
118#ifndef NO_PORT_GEN
119#define IE_BITS_GEN_MASK 0xff000000 /* 8 bits for generation */
120#define IE_BITS_GEN(bits) ((bits) & IE_BITS_GEN_MASK)
121#define IE_BITS_GEN_ONE 0x04000000 /* low bit of generation */
122#define IE_BITS_ROLL_POS 22 /* LSB pos of generation rollover */
123#define IE_BITS_ROLL_BITS 2 /* number of generation rollover bits */
124#define IE_BITS_ROLL_MASK (((1 << IE_BITS_ROLL_BITS) - 1) << IE_BITS_ROLL_POS)
125#define IE_BITS_ROLL(bits) ((((bits) & IE_BITS_ROLL_MASK) << 8) ^ IE_BITS_GEN_MASK)
126
127/*
128 * Restart a generation counter with the specified bits for the rollover point.
129 * There are 4 different rollover points:
130 * bits rollover period
131 * 0 0 64
132 * 0 1 48
133 * 1 0 32
134 * 1 1 16
135 */
136static inline ipc_entry_bits_t ipc_entry_new_rollpoint(
137 ipc_entry_bits_t rollbits)
138{
139 rollbits = (rollbits << IE_BITS_ROLL_POS) & IE_BITS_ROLL_MASK;
140 ipc_entry_bits_t newgen = IE_BITS_GEN_MASK + IE_BITS_GEN_ONE;
141 return (newgen | rollbits);
142}
143
144/*
145 * Get the next gencount, modulo the entry's rollover point. If the sum rolls over,
146 * the caller should re-start the generation counter with a different rollpoint.
147 */
148static inline ipc_entry_bits_t ipc_entry_new_gen(
149 ipc_entry_bits_t oldgen)
150{
151 ipc_entry_bits_t sum = (oldgen + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK;
152 ipc_entry_bits_t roll = oldgen & IE_BITS_ROLL_MASK;
153 ipc_entry_bits_t newgen = (sum % IE_BITS_ROLL(oldgen)) | roll;
154 return newgen;
155}
156
157/* Determine if a gencount has rolled over or not. */
158static inline boolean_t ipc_entry_gen_rolled(
159 ipc_entry_bits_t oldgen,
160 ipc_entry_bits_t newgen)
161{
162 return (oldgen & IE_BITS_GEN_MASK) > (newgen & IE_BITS_GEN_MASK);
163}
164
165#else
166#define IE_BITS_GEN_MASK 0
167#define IE_BITS_GEN(bits) 0
168#define IE_BITS_GEN_ONE 0
169#define IE_BITS_ROLL_POS 0
170#define IE_BITS_ROLL_MASK 0
171#define IE_BITS_ROLL(bits) (bits)
172
173static inline ipc_entry_bits_t ipc_entry_new_rollpoint(
174 ipc_entry_bits_t rollbits)
175{
176 return 0;
177}
178
179static inline ipc_entry_bits_t ipc_entry_new_gen(
180 ipc_entry_bits_t oldgen)
181{
182 return 0;
183}
184
185static inline boolean_t ipc_entry_gen_rolled(
186 ipc_entry_bits_t oldgen,
187 ipc_entry_bits_t newgen)
188{
189 return FALSE;
190}
191
192#endif /* !USE_PORT_GEN */
193
194#define IE_BITS_RIGHT_MASK 0x007fffff /* relevant to the right */
195/*
196 * Exported interfaces
197 */
198
199/* Search for entry in a space by name */
200extern ipc_entry_t ipc_entry_lookup(
201 ipc_space_t space,
202 mach_port_name_t name);
203
204/* Hold a number of entries in a locked space */
205extern kern_return_t ipc_entries_hold(
206 ipc_space_t space,
207 natural_t count);
208
209/* claim and initialize a held entry in a locked space */
210extern kern_return_t ipc_entry_claim(
211 ipc_space_t space,
212 mach_port_name_t *namep,
213 ipc_entry_t *entryp);
214
215/* Allocate an entry in a space */
216extern kern_return_t ipc_entry_get(
217 ipc_space_t space,
218 mach_port_name_t *namep,
219 ipc_entry_t *entryp);
220
221/* Allocate an entry in a space, growing the space if necessary */
222extern kern_return_t ipc_entry_alloc(
223 ipc_space_t space,
224 mach_port_name_t *namep,
225 ipc_entry_t *entryp);
226
227/* Allocate/find an entry in a space with a specific name */
228extern kern_return_t ipc_entry_alloc_name(
229 ipc_space_t space,
230 mach_port_name_t name,
231 ipc_entry_t *entryp);
232
233/* Deallocate an entry from a space */
234extern void ipc_entry_dealloc(
235 ipc_space_t space,
236 mach_port_name_t name,
237 ipc_entry_t entry);
238
239/* Mark and entry modified in a space */
240extern void ipc_entry_modified(
241 ipc_space_t space,
242 mach_port_name_t name,
243 ipc_entry_t entry);
244
245/* Grow the table in a space */
246extern kern_return_t ipc_entry_grow_table(
247 ipc_space_t space,
248 ipc_table_elems_t target_size);
249
250/* mask on/off default entry generation bits */
251extern mach_port_name_t ipc_entry_name_mask(
252 mach_port_name_t name);
253#endif /* _IPC_IPC_ENTRY_H_ */
254