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  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52 /*
  53  *      File:   ipc/ipc_entry.h
  54  *      Author: Rich Draves
  55  *      Date:   1989
  56  *
  57  *      Definitions for translation entries, which represent
  58  *      tasks' capabilities for ports and port sets.
  59  */
  60
  61 #ifndef _IPC_IPC_ENTRY_H_
  62 #define _IPC_IPC_ENTRY_H_
  63
  64 #include <mach/mach_types.h>
  65 #include <mach/port.h>
  66 #include <mach/kern_return.h>
  67
  68 #include <kern/kern_types.h>
  69 #include <kern/zalloc.h>
  70
  71 #include <ipc/ipc_types.h>
  72
  73 /*
  74  *      Spaces hold capabilities for ipc_object_t's.
  75  *      Each ipc_entry_t records a capability.  Most capabilities have
  76  *      small names, and the entries are elements of a table.
  77  *      Capabilities can have large names, and a splay tree holds
  78  *      those entries.  The cutoff point between the table and the tree
  79  *      is adjusted dynamically to minimize memory consumption.
  80  *
  81  *      The ie_index field of entries in the table implements
  82  *      a ordered hash table with open addressing and linear probing.
  83  *      This hash table converts (space, object) -> name.
  84  *      It is used independently of the other fields.
  85  *
  86  *      Free (unallocated) entries in the table have null ie_object
  87  *      fields.  The ie_bits field is zero except for IE_BITS_GEN.
  88  *      The ie_next (ie_request) field links free entries into a free list.
  89  *
  90  *      The first entry in the table (index 0) is always free.
  91  *      It is used as the head of the free list.
  92  */
  93
  94 struct ipc_entry {
  95         struct ipc_object *ie_object;
  96         ipc_entry_bits_t ie_bits;
  97         union {
  98                 mach_port_index_t next;         /* next in freelist, or...  */
  99                 ipc_table_index_t request;      /* dead name request notify */
 100         } index;
 101         union {
 102                 mach_port_index_t table;
 103                 struct ipc_tree_entry *tree;
 104         } hash;
 105 };
 106
 107 #define ie_request      index.request
 108 #define ie_next         index.next
 109 #define ie_index        hash.table
 110
 111 #define IE_BITS_UREFS_MASK      0x0000ffff      /* 16 bits of user-reference */
 112 #define IE_BITS_UREFS(bits)     ((bits) & IE_BITS_UREFS_MASK)
 113
 114 #define IE_BITS_TYPE_MASK       0x001f0000      /* 5 bits of capability type */
 115 #define IE_BITS_TYPE(bits)      ((bits) & IE_BITS_TYPE_MASK)
 116
 117 #define IE_BITS_COLLISION       0x00800000      /* 1 bit for collisions */
 118
 119
 120 #ifndef NO_PORT_GEN
 121 #define IE_BITS_GEN_MASK        0xff000000      /* 8 bits for generation */
 122 #define IE_BITS_GEN(bits)       ((bits) & IE_BITS_GEN_MASK)
 123 #define IE_BITS_GEN_ONE         0x04000000      /* low bit of generation */
 124 #define IE_BITS_NEW_GEN(old)    (((old) + IE_BITS_GEN_ONE) & IE_BITS_GEN_MASK)
 125 #else
 126 #define IE_BITS_GEN_MASK        0
 127 #define IE_BITS_GEN(bits)       0
 128 #define IE_BITS_GEN_ONE         0
 129 #define IE_BITS_NEW_GEN(old)    (old)
 130 #endif  /* !USE_PORT_GEN */
 131
 132
 133 #define IE_BITS_RIGHT_MASK      0x007fffff      /* relevant to the right */
 134
 135 struct ipc_tree_entry {
 136         struct ipc_entry ite_entry;
 137         mach_port_name_t ite_name;
 138         struct ipc_space *ite_space;
 139         struct ipc_tree_entry *ite_lchild;
 140         struct ipc_tree_entry *ite_rchild;
 141 };
 142
 143 #define ite_bits        ite_entry.ie_bits
 144 #define ite_object      ite_entry.ie_object
 145 #define ite_request     ite_entry.ie_request
 146 #define ite_next        ite_entry.hash.tree
 147
 148 extern zone_t ipc_tree_entry_zone;
 149
 150 #define ite_alloc()     ((ipc_tree_entry_t) zalloc(ipc_tree_entry_zone))
 151 #define ite_free(ite)   zfree(ipc_tree_entry_zone, (ite))
 152
 153 /*
 154  * Exported interfaces
 155  */
 156
 157 /* Search for entry in a space by name */
 158 extern ipc_entry_t ipc_entry_lookup(
 159         ipc_space_t             space,
 160         mach_port_name_t        name);
 161
 162 /* Allocate an entry in a space */
 163 extern kern_return_t ipc_entry_get(
 164         ipc_space_t             space,
 165         mach_port_name_t        *namep,
 166         ipc_entry_t             *entryp);
 167
 168 /* Allocate an entry in a space, growing the space if necessary */
 169 extern kern_return_t ipc_entry_alloc(
 170         ipc_space_t             space,
 171         mach_port_name_t        *namep,
 172         ipc_entry_t             *entryp);
 173
 174 /* Allocate/find an entry in a space with a specific name */
 175 extern kern_return_t ipc_entry_alloc_name(
 176         ipc_space_t             space,
 177         mach_port_name_t        name,
 178         ipc_entry_t             *entryp);
 179
 180 /* Deallocate an entry from a space */
 181 extern void ipc_entry_dealloc(
 182         ipc_space_t             space,
 183         mach_port_name_t        name,
 184         ipc_entry_t             entry);
 185
 186 /* Grow the table in a space */
 187 extern kern_return_t ipc_entry_grow_table(
 188         ipc_space_t             space,
 189         ipc_table_elems_t       target_size);
 190
 191 #endif  /* _IPC_IPC_ENTRY_H_ */