osfmk/ipc/ipc_entry.h

   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,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  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  *      Capabilities can have large names, and a splay tree holds
  84  *      those entries.  The cutoff point between the table and the tree
  85  *      is adjusted dynamically to minimize memory consumption.
  86  *
  87  *      The ie_index field of entries in the table implements
  88  *      a ordered hash table with open addressing and linear probing.
  89  *      This hash table converts (space, object) -> name.
  90  *      It is used independently of the other fields.
  91  *
  92  *      Free (unallocated) entries in the table have null ie_object
  93  *      fields.  The ie_bits field is zero except for IE_BITS_GEN.
  94  *      The ie_next (ie_request) field links free entries into a free list.
  95  *
  96  *      The first entry in the table (index 0) is always free.
  97  *      It is used as the head of the free list.
  98  */
  99
 100 struct ipc_entry {
 101         struct ipc_object *ie_object;
 102         ipc_entry_bits_t ie_bits;
 103         union {
 104                 mach_port_index_t next;         /* next in freelist, or...  */
 105                 ipc_table_index_t request;      /* dead name request notify */
 106         } index;
 107         union {
 108                 mach_port_index_t table;
 109                 struct ipc_tree_entry *tree;
 110         } hash;
 111 };
 112
 113 #define ie_request      index.request
 114 #define ie_next         index.next
 115 #define ie_index        hash.table
 116
 117 #define IE_BITS_UREFS_MASK      0x0000ffff      /* 16 bits of user-reference */
 118 #define IE_BITS_UREFS(bits)     ((bits) & IE_BITS_UREFS_MASK)
 119
 120 #define IE_BITS_TYPE_MASK       0x001f0000      /* 5 bits of capability type */
 121 #define IE_BITS_TYPE(bits)      ((bits) & IE_BITS_TYPE_MASK)
 122
 123 #define IE_BITS_COLLISION       0x00800000      /* 1 bit for collisions */
 124
 125
 126 #ifndef NO_PORT_GEN
 127 #define IE_BITS_GEN_MASK        0xff000000      /* 8 bits for generation */
 128 #define IE_BITS_GEN(bits)       ((bits) & IE_BITS_GEN_MASK)
 129 #define IE_BITS_GEN_ONE         0x04000000      /* low bit of generation */
 130 #define IE_BITS_NEW_GEN(old)    (((old) + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK)
 131 #else
 132 #define IE_BITS_GEN_MASK        0
 133 #define IE_BITS_GEN(bits)       0
 134 #define IE_BITS_GEN_ONE         0
 135 #define IE_BITS_NEW_GEN(old)    (old)
 136 #endif  /* !USE_PORT_GEN */
 137
 138
 139 #define IE_BITS_RIGHT_MASK      0x007fffff      /* relevant to the right */
 140
 141 struct ipc_tree_entry {
 142         struct ipc_entry ite_entry;
 143         mach_port_name_t ite_name;
 144         struct ipc_space *ite_space;
 145         struct ipc_tree_entry *ite_lchild;
 146         struct ipc_tree_entry *ite_rchild;
 147 };
 148
 149 #define ite_bits        ite_entry.ie_bits
 150 #define ite_object      ite_entry.ie_object
 151 #define ite_request     ite_entry.ie_request
 152 #define ite_next        ite_entry.hash.tree
 153
 154 extern zone_t ipc_tree_entry_zone;
 155
 156 #define ite_alloc()     ((ipc_tree_entry_t) zalloc(ipc_tree_entry_zone))
 157 #define ite_free(ite)   zfree(ipc_tree_entry_zone, (ite))
 158
 159 /*
 160  * Exported interfaces
 161  */
 162
 163 /* Search for entry in a space by name */
 164 extern ipc_entry_t ipc_entry_lookup(
 165         ipc_space_t             space,
 166         mach_port_name_t        name);
 167
 168 /* Allocate an entry in a space */
 169 extern kern_return_t ipc_entry_get(
 170         ipc_space_t             space,
 171         mach_port_name_t        *namep,
 172         ipc_entry_t             *entryp);
 173
 174 /* Allocate an entry in a space, growing the space if necessary */
 175 extern kern_return_t ipc_entry_alloc(
 176         ipc_space_t             space,
 177         mach_port_name_t        *namep,
 178         ipc_entry_t             *entryp);
 179
 180 /* Allocate/find an entry in a space with a specific name */
 181 extern kern_return_t ipc_entry_alloc_name(
 182         ipc_space_t             space,
 183         mach_port_name_t        name,
 184         ipc_entry_t             *entryp);
 185
 186 /* Deallocate an entry from a space */
 187 extern void ipc_entry_dealloc(
 188         ipc_space_t             space,
 189         mach_port_name_t        name,
 190         ipc_entry_t             entry);
 191
 192 /* Grow the table in a space */
 193 extern kern_return_t ipc_entry_grow_table(
 194         ipc_space_t             space,
 195         ipc_table_elems_t       target_size);
 196
 197 #endif  /* _IPC_IPC_ENTRY_H_ */