osfmk/ipc/ipc_entry.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  */
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  31  * All Rights Reserved.
  32  *
  33  * Permission to use, copy, modify and distribute this software and its
  34  * documentation is hereby granted, provided that both the copyright
  35  * notice and this permission notice appear in all copies of the
  36  * software, derivative works or modified versions, and any portions
  37  * thereof, and that both notices appear in supporting documentation.
  38  *
  39  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  40  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  41  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  42  *
  43  * Carnegie Mellon requests users of this software to return to
  44  *
  45  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  46  *  School of Computer Science
  47  *  Carnegie Mellon University
  48  *  Pittsburgh PA 15213-3890
  49  *
  50  * any improvements or extensions that they make and grant Carnegie Mellon
  51  * the rights to redistribute these changes.
  52  */
  53 /*
  54  */
  55 /*
  56  *      File:   ipc/ipc_entry.h
  57  *      Author: Rich Draves
  58  *      Date:   1989
  59  *
  60  *      Definitions for translation entries, which represent
  61  *      tasks' capabilities for ports and port sets.
  62  */
  63
  64 #ifndef _IPC_IPC_ENTRY_H_
  65 #define _IPC_IPC_ENTRY_H_
  66
  67 #include <mach/port.h>
  68 #include <mach/kern_return.h>
  69 #include <kern/zalloc.h>
  70 #include <ipc/port.h>
  71 #include <ipc/ipc_table.h>
  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 typedef natural_t ipc_entry_bits_t;
  96 typedef ipc_table_elems_t ipc_entry_num_t;      /* number of entries */
  97
  98 typedef struct ipc_entry {
  99         struct ipc_object *ie_object;
 100         ipc_entry_bits_t ie_bits;
 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         union {
 106                 mach_port_index_t table;
 107                 struct ipc_tree_entry *tree;
 108         } hash;
 109 } *ipc_entry_t;
 110
 111 #define IE_NULL         ((ipc_entry_t) 0)
 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 typedef 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 } *ipc_tree_entry_t;
 148
 149 #define ITE_NULL        ((ipc_tree_entry_t) 0)
 150
 151 #define ite_bits        ite_entry.ie_bits
 152 #define ite_object      ite_entry.ie_object
 153 #define ite_request     ite_entry.ie_request
 154 #define ite_next        ite_entry.hash.tree
 155
 156 extern zone_t ipc_tree_entry_zone;
 157
 158 #define ite_alloc()     ((ipc_tree_entry_t) zalloc(ipc_tree_entry_zone))
 159 #define ite_free(ite)   zfree(ipc_tree_entry_zone, (vm_offset_t) (ite))
 160
 161 /*
 162  * Exported interfaces
 163  */
 164
 165 /* Search for entry in a space by name */
 166 extern ipc_entry_t ipc_entry_lookup(
 167         ipc_space_t             space,
 168         mach_port_name_t        name);
 169
 170 /* Allocate an entry in a space */
 171 extern kern_return_t ipc_entry_get(
 172         ipc_space_t             space,
 173         mach_port_name_t        *namep,
 174         ipc_entry_t             *entryp);
 175
 176 /* Allocate an entry in a space, growing the space if necessary */
 177 extern kern_return_t ipc_entry_alloc(
 178         ipc_space_t             space,
 179         mach_port_name_t        *namep,
 180         ipc_entry_t             *entryp);
 181
 182 /* Allocate/find an entry in a space with a specific name */
 183 extern kern_return_t ipc_entry_alloc_name(
 184         ipc_space_t             space,
 185         mach_port_name_t        name,
 186         ipc_entry_t             *entryp);
 187
 188 /* Deallocate an entry from a space */
 189 extern void ipc_entry_dealloc(
 190         ipc_space_t             space,
 191         mach_port_name_t        name,
 192         ipc_entry_t             entry);
 193
 194 /* Grow the table in a space */
 195 extern kern_return_t ipc_entry_grow_table(
 196         ipc_space_t     space,
 197         int             target_size);
 198
 199 #endif  /* _IPC_IPC_ENTRY_H_ */