osfmk/ipc/ipc_entry.h

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * @OSF_COPYRIGHT@
  25  */
  26 /*
  27  * Mach Operating System
  28  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  29  * All Rights Reserved.
  30  *
  31  * Permission to use, copy, modify and distribute this software and its
  32  * documentation is hereby granted, provided that both the copyright
  33  * notice and this permission notice appear in all copies of the
  34  * software, derivative works or modified versions, and any portions
  35  * thereof, and that both notices appear in supporting documentation.
  36  *
  37  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  38  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  39  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  40  *
  41  * Carnegie Mellon requests users of this software to return to
  42  *
  43  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  44  *  School of Computer Science
  45  *  Carnegie Mellon University
  46  *  Pittsburgh PA 15213-3890
  47  *
  48  * any improvements or extensions that they make and grant Carnegie Mellon
  49  * the rights to redistribute these changes.
  50  */
  51 /*
  52  */
  53 /*
  54  *      File:   ipc/ipc_entry.h
  55  *      Author: Rich Draves
  56  *      Date:   1989
  57  *
  58  *      Definitions for translation entries, which represent
  59  *      tasks' capabilities for ports and port sets.
  60  */
  61
  62 #ifndef _IPC_IPC_ENTRY_H_
  63 #define _IPC_IPC_ENTRY_H_
  64
  65 #include <mach/mach_types.h>
  66 #include <mach/port.h>
  67 #include <mach/kern_return.h>
  68
  69 #include <kern/kern_types.h>
  70 #include <kern/zalloc.h>
  71
  72 #include <ipc/ipc_types.h>
  73
  74 /*
  75  *      Spaces hold capabilities for ipc_object_t's.
  76  *      Each ipc_entry_t records a capability.  Most capabilities have
  77  *      small names, and the entries are elements of a table.
  78  *      Capabilities can have large names, and a splay tree holds
  79  *      those entries.  The cutoff point between the table and the tree
  80  *      is adjusted dynamically to minimize memory consumption.
  81  *
  82  *      The ie_index field of entries in the table implements
  83  *      a ordered hash table with open addressing and linear probing.
  84  *      This hash table converts (space, object) -> name.
  85  *      It is used independently of the other fields.
  86  *
  87  *      Free (unallocated) entries in the table have null ie_object
  88  *      fields.  The ie_bits field is zero except for IE_BITS_GEN.
  89  *      The ie_next (ie_request) field links free entries into a free list.
  90  *
  91  *      The first entry in the table (index 0) is always free.
  92  *      It is used as the head of the free list.
  93  */
  94
  95 struct ipc_entry {
  96         struct ipc_object *ie_object;
  97         ipc_entry_bits_t ie_bits;
  98         union {
  99                 mach_port_index_t next;         /* next in freelist, or...  */
 100                 ipc_table_index_t request;      /* dead name request notify */
 101         } index;
 102         union {
 103                 mach_port_index_t table;
 104                 struct ipc_tree_entry *tree;
 105         } hash;
 106 };
 107
 108 #define ie_request      index.request
 109 #define ie_next         index.next
 110 #define ie_index        hash.table
 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 #define IE_BITS_COLLISION       0x00800000      /* 1 bit for collisions */
 119
 120
 121 #ifndef NO_PORT_GEN
 122 #define IE_BITS_GEN_MASK        0xff000000      /* 8 bits for generation */
 123 #define IE_BITS_GEN(bits)       ((bits) & IE_BITS_GEN_MASK)
 124 #define IE_BITS_GEN_ONE         0x04000000      /* low bit of generation */
 125 #define IE_BITS_NEW_GEN(old)    (((old) + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK)
 126 #else
 127 #define IE_BITS_GEN_MASK        0
 128 #define IE_BITS_GEN(bits)       0
 129 #define IE_BITS_GEN_ONE         0
 130 #define IE_BITS_NEW_GEN(old)    (old)
 131 #endif  /* !USE_PORT_GEN */
 132
 133
 134 #define IE_BITS_RIGHT_MASK      0x007fffff      /* relevant to the right */
 135
 136 struct ipc_tree_entry {
 137         struct ipc_entry ite_entry;
 138         mach_port_name_t ite_name;
 139         struct ipc_space *ite_space;
 140         struct ipc_tree_entry *ite_lchild;
 141         struct ipc_tree_entry *ite_rchild;
 142 };
 143
 144 #define ite_bits        ite_entry.ie_bits
 145 #define ite_object      ite_entry.ie_object
 146 #define ite_request     ite_entry.ie_request
 147 #define ite_next        ite_entry.hash.tree
 148
 149 extern zone_t ipc_tree_entry_zone;
 150
 151 #define ite_alloc()     ((ipc_tree_entry_t) zalloc(ipc_tree_entry_zone))
 152 #define ite_free(ite)   zfree(ipc_tree_entry_zone, (ite))
 153
 154 /*
 155  * Exported interfaces
 156  */
 157
 158 /* Search for entry in a space by name */
 159 extern ipc_entry_t ipc_entry_lookup(
 160         ipc_space_t             space,
 161         mach_port_name_t        name);
 162
 163 /* Allocate an entry in a space */
 164 extern kern_return_t ipc_entry_get(
 165         ipc_space_t             space,
 166         mach_port_name_t        *namep,
 167         ipc_entry_t             *entryp);
 168
 169 /* Allocate an entry in a space, growing the space if necessary */
 170 extern kern_return_t ipc_entry_alloc(
 171         ipc_space_t             space,
 172         mach_port_name_t        *namep,
 173         ipc_entry_t             *entryp);
 174
 175 /* Allocate/find an entry in a space with a specific name */
 176 extern kern_return_t ipc_entry_alloc_name(
 177         ipc_space_t             space,
 178         mach_port_name_t        name,
 179         ipc_entry_t             *entryp);
 180
 181 /* Deallocate an entry from a space */
 182 extern void ipc_entry_dealloc(
 183         ipc_space_t             space,
 184         mach_port_name_t        name,
 185         ipc_entry_t             entry);
 186
 187 /* Grow the table in a space */
 188 extern kern_return_t ipc_entry_grow_table(
 189         ipc_space_t             space,
 190         ipc_table_elems_t       target_size);
 191
 192 #endif  /* _IPC_IPC_ENTRY_H_ */