iokit/Kernel/IOSharedDataQueue.cpp

   1 /*
   2  * Copyright (c) 1998-2000 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
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  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,
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  23  * Please see the License for the specific language governing rights and
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  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <IOKit/IOSharedDataQueue.h>
  30 #include <IOKit/IODataQueueShared.h>
  31 #include <IOKit/IOLib.h>
  32 #include <IOKit/IOMemoryDescriptor.h>
  33
  34 #ifdef dequeue
  35 #undef dequeue
  36 #endif
  37
  38 #define super IODataQueue
  39
  40 OSDefineMetaClassAndStructors(IOSharedDataQueue, IODataQueue)
  41
  42 IOSharedDataQueue *IOSharedDataQueue::withCapacity(UInt32 size)
  43 {
  44     IOSharedDataQueue *dataQueue = new IOSharedDataQueue;
  45
  46     if (dataQueue) {
  47         if  (!dataQueue->initWithCapacity(size)) {
  48             dataQueue->release();
  49             dataQueue = 0;
  50         }
  51     }
  52
  53     return dataQueue;
  54 }
  55
  56 IOSharedDataQueue *IOSharedDataQueue::withEntries(UInt32 numEntries, UInt32 entrySize)
  57 {
  58     IOSharedDataQueue *dataQueue = new IOSharedDataQueue;
  59
  60     if (dataQueue) {
  61         if (!dataQueue->initWithEntries(numEntries, entrySize)) {
  62             dataQueue->release();
  63             dataQueue = 0;
  64         }
  65     }
  66
  67     return dataQueue;
  68 }
  69
  70 Boolean IOSharedDataQueue::initWithCapacity(UInt32 size)
  71 {
  72     IODataQueueAppendix *   appendix;
  73
  74     if (!super::init()) {
  75         return false;
  76     }
  77
  78     dataQueue = (IODataQueueMemory *)IOMallocAligned(round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE), PAGE_SIZE);
  79     if (dataQueue == 0) {
  80         return false;
  81     }
  82
  83     dataQueue->queueSize    = size;
  84     dataQueue->head         = 0;
  85     dataQueue->tail         = 0;
  86
  87     appendix            = (IODataQueueAppendix *)((UInt8 *)dataQueue + size + DATA_QUEUE_MEMORY_HEADER_SIZE);
  88     appendix->version   = 0;
  89     notifyMsg           = &(appendix->msgh);
  90     setNotificationPort(MACH_PORT_NULL);
  91
  92     return true;
  93 }
  94
  95 void IOSharedDataQueue::free()
  96 {
  97     if (dataQueue) {
  98         IOFreeAligned(dataQueue, round_page(dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE));
  99         dataQueue = NULL;
 100     }
 101
 102     super::free();
 103 }
 104
 105 IOMemoryDescriptor *IOSharedDataQueue::getMemoryDescriptor()
 106 {
 107     IOMemoryDescriptor *descriptor = 0;
 108
 109     if (dataQueue != 0) {
 110         descriptor = IOMemoryDescriptor::withAddress(dataQueue, dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE, kIODirectionOutIn);
 111     }
 112
 113     return descriptor;
 114 }
 115
 116
 117 IODataQueueEntry * IOSharedDataQueue::peek()
 118 {
 119     IODataQueueEntry *entry = 0;
 120
 121     if (dataQueue && (dataQueue->head != dataQueue->tail)) {
 122         IODataQueueEntry *  head                = 0;
 123         UInt32              headSize    = 0;
 124         UInt32              headOffset  = dataQueue->head;
 125         UInt32              queueSize   = dataQueue->queueSize;
 126
 127         head            = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
 128         headSize        = head->size;
 129
 130                 // Check if there's enough room before the end of the queue for a header.
 131         // If there is room, check if there's enough room to hold the header and
 132         // the data.
 133
 134         if ((headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
 135             ((headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE) > queueSize))
 136         {
 137             // No room for the header or the data, wrap to the beginning of the queue.
 138             entry = dataQueue->queue;
 139         } else {
 140             entry = head;
 141         }
 142     }
 143
 144     return entry;
 145 }
 146
 147 Boolean IOSharedDataQueue::dequeue(void *data, UInt32 *dataSize)
 148 {
 149     Boolean             retVal          = TRUE;
 150     IODataQueueEntry *  entry           = 0;
 151     UInt32              entrySize       = 0;
 152     UInt32              newHeadOffset   = 0;
 153
 154     if (dataQueue) {
 155         if (dataQueue->head != dataQueue->tail) {
 156             IODataQueueEntry *  head            = 0;
 157             UInt32              headSize    = 0;
 158             UInt32              headOffset  = dataQueue->head;
 159             UInt32              queueSize   = dataQueue->queueSize;
 160
 161             head                = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
 162             headSize    = head->size;
 163
 164             // we wraped around to beginning, so read from there
 165                         // either there was not even room for the header
 166                         if ((headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
 167                                 // or there was room for the header, but not for the data
 168                                 ((headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE) > queueSize)) {
 169                 entry           = dataQueue->queue;
 170                 entrySize       = entry->size;
 171                 newHeadOffset   = entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 172             // else it is at the end
 173             } else {
 174                 entry           = head;
 175                 entrySize       = entry->size;
 176                 newHeadOffset   = headOffset + entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 177             }
 178         }
 179
 180         if (entry) {
 181             if (data) {
 182                 if (dataSize) {
 183                     if (entrySize <= *dataSize) {
 184                         memcpy(data, &(entry->data), entrySize);
 185                         dataQueue->head = newHeadOffset;
 186                     } else {
 187                         retVal = FALSE;
 188                     }
 189                 } else {
 190                     retVal = FALSE;
 191                 }
 192             } else {
 193                 dataQueue->head = newHeadOffset;
 194             }
 195
 196             if (dataSize) {
 197                 *dataSize = entrySize;
 198             }
 199         } else {
 200             retVal = FALSE;
 201         }
 202     } else {
 203         retVal = FALSE;
 204     }
 205
 206     return retVal;
 207 }
 208
 209
 210 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 0);
 211 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 1);
 212 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 2);
 213 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 3);
 214 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 4);
 215 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 5);
 216 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 6);
 217 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 7);