osfmk/ipc/ipc_table.c

   1 /*
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   3  *
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  13  * terms of an Apple operating system software license agreement.
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  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
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  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_table.c
  60  *      Author: Rich Draves
  61  *      Date:   1989
  62  *
  63  *      Functions to manipulate tables of IPC capabilities.
  64  */
  65
  66 #include <mach/kern_return.h>
  67 #include <mach/vm_param.h>
  68 #include <ipc/ipc_table.h>
  69 #include <ipc/ipc_port.h>
  70 #include <ipc/ipc_entry.h>
  71 #include <kern/kalloc.h>
  72 #include <vm/vm_kern.h>
  73
  74 ipc_table_size_t ipc_table_entries = NULL;
  75 unsigned int ipc_table_entries_size = CONFIG_IPC_TABLE_ENTRIES_STEPS;
  76
  77 ipc_table_size_t ipc_table_requests;
  78 unsigned int ipc_table_requests_size = 64;
  79
  80 static void
  81 ipc_table_fill(
  82         ipc_table_size_t        its,         /* array to fill */
  83         unsigned int            num,         /* size of array */
  84         unsigned int            min,         /* at least this many elements */
  85         vm_size_t               elemsize)    /* size of elements */
  86 {
  87         unsigned int index;
  88         vm_size_t minsize = min * elemsize;
  89         vm_size_t size;
  90         vm_size_t incrsize;
  91
  92         /* first use powers of two, up to the page size */
  93
  94         for (index = 0, size = 1;
  95             (index < num) && (size < PAGE_MAX_SIZE);
  96             size <<= 1) {
  97                 if (size >= minsize) {
  98                         its[index].its_size = (ipc_table_elems_t)(size / elemsize);
  99                         index++;
 100                 }
 101         }
 102
 103         /* then increments of a page, then two pages, etc. */
 104
 105         for (incrsize = PAGE_MAX_SIZE; index < num;) {
 106                 unsigned int period;
 107
 108                 for (period = 0;
 109                     (period < 15) && (index < num);
 110                     period++, size += incrsize) {
 111                         if (size >= minsize) {
 112                                 its[index].its_size = (ipc_table_elems_t)(size / elemsize);
 113                                 index++;
 114                         }
 115                 }
 116                 if (incrsize < (vm_size_t)(PAGE_MAX_SIZE << 3)) {
 117                         incrsize <<= 1;
 118                 }
 119         }
 120 }
 121
 122 void
 123 ipc_table_init(void)
 124 {
 125         ipc_table_entries = (ipc_table_size_t)
 126             kalloc(sizeof(struct ipc_table_size) *
 127             ipc_table_entries_size);
 128         assert(ipc_table_entries != ITS_NULL);
 129
 130         ipc_table_fill(ipc_table_entries, ipc_table_entries_size - 1,
 131             16, sizeof(struct ipc_entry));
 132
 133         /* the last two elements should have the same size */
 134
 135         ipc_table_entries[ipc_table_entries_size - 1].its_size =
 136             ipc_table_entries[ipc_table_entries_size - 2].its_size;
 137
 138         /* make sure the robin hood hashing in ipc hash will work */
 139         assert(ipc_table_entries[ipc_table_entries_size - 1].its_size <=
 140             IPC_ENTRY_INDEX_MAX);
 141
 142         ipc_table_requests = (ipc_table_size_t)
 143             kalloc(sizeof(struct ipc_table_size) *
 144             ipc_table_requests_size);
 145         assert(ipc_table_requests != ITS_NULL);
 146
 147         ipc_table_fill(ipc_table_requests, ipc_table_requests_size - 1,
 148             2, sizeof(struct ipc_port_request));
 149
 150         /* the last element should have zero size */
 151
 152         ipc_table_requests[ipc_table_requests_size - 1].its_size = 0;
 153 }
 154
 155
 156 /*
 157  *      Routine: ipc_table_max_entries
 158  *      Purpose:
 159  *              returns the maximum number of entries an IPC space
 160  *              is allowed to contain (the maximum size to which it will grow)
 161  *      Conditions:
 162  *              none
 163  */
 164 unsigned int
 165 ipc_table_max_entries(void)
 166 {
 167         if (!ipc_table_entries || ipc_table_entries_size < 2) {
 168                 return 0;
 169         }
 170         return (unsigned int)ipc_table_entries[ipc_table_entries_size - 1].its_size;
 171 }
 172
 173
 174 /*
 175  *      Routine: ipc_table_max_requests
 176  *      Purpose:
 177  *              returns the maximum number of requests an IPC request table
 178  *              is allowed to contain (the maximum size to which it will grow)
 179  *      Conditions:
 180  *              none
 181  */
 182 unsigned int
 183 ipc_table_max_requests(void)
 184 {
 185         if (!ipc_table_requests || ipc_table_requests_size < 2) {
 186                 return 0;
 187         }
 188         return (unsigned int)ipc_table_requests[ipc_table_requests_size - 2].its_size;
 189 }
 190
 191
 192 /*
 193  *      Routine:        ipc_table_alloc
 194  *      Purpose:
 195  *              Allocate a table.
 196  *      Conditions:
 197  *              May block.
 198  */
 199
 200 void *
 201 ipc_table_alloc(
 202         vm_size_t       size)
 203 {
 204         return kalloc(size);
 205 }
 206
 207
 208 /*
 209  *      Routine:        ipc_table_free
 210  *      Purpose:
 211  *              Free a table allocated with ipc_table_alloc.
 212  *      Conditions:
 213  *              May block.
 214  */
 215
 216 void
 217 ipc_table_free(
 218         vm_size_t       size,
 219         void *          table)
 220 {
 221         kfree(table, size);
 222 }