iokit/Kernel/IODataQueue.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 #define DISABLE_DATAQUEUE_WARNING
  30
  31 #include <IOKit/IODataQueue.h>
  32
  33 #undef DISABLE_DATAQUEUE_WARNING
  34
  35 #include <IOKit/IODataQueueShared.h>
  36 #include <IOKit/IOLib.h>
  37 #include <IOKit/IOMemoryDescriptor.h>
  38 #include <libkern/OSAtomic.h>
  39
  40 struct IODataQueueInternal
  41 {
  42     mach_msg_header_t msg;
  43     UInt32            queueSize;
  44 };
  45
  46 #ifdef enqueue
  47 #undef enqueue
  48 #endif
  49
  50 #ifdef dequeue
  51 #undef dequeue
  52 #endif
  53
  54 #define super OSObject
  55
  56 OSDefineMetaClassAndStructors(IODataQueue, OSObject)
  57
  58 IODataQueue *IODataQueue::withCapacity(UInt32 size)
  59 {
  60     IODataQueue *dataQueue = new IODataQueue;
  61
  62     if (dataQueue) {
  63         if  (!dataQueue->initWithCapacity(size)) {
  64             dataQueue->release();
  65             dataQueue = 0;
  66         }
  67     }
  68
  69     return dataQueue;
  70 }
  71
  72 IODataQueue *IODataQueue::withEntries(UInt32 numEntries, UInt32 entrySize)
  73 {
  74     IODataQueue *dataQueue = new IODataQueue;
  75
  76     if (dataQueue) {
  77         if (!dataQueue->initWithEntries(numEntries, entrySize)) {
  78             dataQueue->release();
  79             dataQueue = 0;
  80         }
  81     }
  82
  83     return dataQueue;
  84 }
  85
  86 Boolean IODataQueue::initWithCapacity(UInt32 size)
  87 {
  88     vm_size_t allocSize = 0;
  89
  90     if (!super::init()) {
  91         return false;
  92     }
  93
  94     if (size > UINT32_MAX - DATA_QUEUE_MEMORY_HEADER_SIZE) {
  95         return false;
  96     }
  97
  98     allocSize = round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE);
  99
 100     if (allocSize < size) {
 101         return false;
 102     }
 103
 104     assert(!notifyMsg);
 105     notifyMsg = IONew(IODataQueueInternal, 1);
 106         if (!notifyMsg) {
 107                 return false;
 108         }
 109     bzero(notifyMsg, sizeof(IODataQueueInternal));
 110     ((IODataQueueInternal *)notifyMsg)->queueSize = size;
 111
 112     dataQueue = (IODataQueueMemory *)IOMallocAligned(allocSize, PAGE_SIZE);
 113     if (dataQueue == 0) {
 114         return false;
 115     }
 116     bzero(dataQueue, allocSize);
 117
 118     dataQueue->queueSize    = size;
 119 //  dataQueue->head         = 0;
 120 //  dataQueue->tail         = 0;
 121
 122     return true;
 123 }
 124
 125 Boolean IODataQueue::initWithEntries(UInt32 numEntries, UInt32 entrySize)
 126 {
 127     // Checking overflow for (numEntries + 1)*(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE):
 128     //  check (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE)
 129     if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 130         //  check (numEntries + 1)
 131         (numEntries > UINT32_MAX-1) ||
 132         //  check (numEntries + 1)*(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE)
 133         (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX/(numEntries+1))) {
 134         return false;
 135     }
 136
 137     return (initWithCapacity((numEntries + 1) * (DATA_QUEUE_ENTRY_HEADER_SIZE + entrySize)));
 138 }
 139
 140 void IODataQueue::free()
 141 {
 142         if (notifyMsg) {
 143                 if (dataQueue) {
 144                         IOFreeAligned(dataQueue, round_page(((IODataQueueInternal *)notifyMsg)->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE));
 145                         dataQueue = NULL;
 146                 }
 147
 148                 IODelete(notifyMsg, IODataQueueInternal, 1);
 149                 notifyMsg = NULL;
 150     }
 151
 152     super::free();
 153
 154     return;
 155 }
 156
 157 Boolean IODataQueue::enqueue(void * data, UInt32 dataSize)
 158 {
 159     const UInt32       head      = dataQueue->head;  // volatile
 160     const UInt32       tail      = dataQueue->tail;
 161     const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 162     UInt32             queueSize;
 163     IODataQueueEntry * entry;
 164
 165     // Check for overflow of entrySize
 166     if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
 167         return false;
 168     }
 169
 170     // Check for underflow of (dataQueue->queueSize - tail)
 171     queueSize = ((IODataQueueInternal *) notifyMsg)->queueSize;
 172     if ((queueSize < tail) || (queueSize < head)) {
 173         return false;
 174     }
 175
 176     if ( tail >= head )
 177     {
 178         // Is there enough room at the end for the entry?
 179         if ((entrySize <= UINT32_MAX - tail) &&
 180             ((tail + entrySize) <= queueSize) )
 181         {
 182             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 183
 184             entry->size = dataSize;
 185             memcpy(&entry->data, data, dataSize);
 186
 187             // The tail can be out of bound when the size of the new entry
 188             // exactly matches the available space at the end of the queue.
 189             // The tail can range from 0 to dataQueue->queueSize inclusive.
 190
 191             OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
 192         }
 193         else if ( head > entrySize )     // Is there enough room at the beginning?
 194         {
 195             // Wrap around to the beginning, but do not allow the tail to catch
 196             // up to the head.
 197
 198             dataQueue->queue->size = dataSize;
 199
 200             // We need to make sure that there is enough room to set the size before
 201             // doing this. The user client checks for this and will look for the size
 202             // at the beginning if there isn't room for it at the end.
 203
 204             if ( ( queueSize - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
 205             {
 206                 ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
 207             }
 208
 209             memcpy(&dataQueue->queue->data, data, dataSize);
 210             OSCompareAndSwap(dataQueue->tail, entrySize, &dataQueue->tail);
 211         }
 212         else
 213         {
 214             return false;    // queue is full
 215         }
 216     }
 217     else
 218     {
 219         // Do not allow the tail to catch up to the head when the queue is full.
 220         // That's why the comparison uses a '>' rather than '>='.
 221
 222         if ( (head - tail) > entrySize )
 223         {
 224             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 225
 226             entry->size = dataSize;
 227             memcpy(&entry->data, data, dataSize);
 228             OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
 229         }
 230         else
 231         {
 232             return false;    // queue is full
 233         }
 234     }
 235
 236     // Send notification (via mach message) that data is available.
 237
 238     if ( ( head == tail )                                                   /* queue was empty prior to enqueue() */
 239     ||   ( dataQueue->head == tail ) )   /* queue was emptied during enqueue() */
 240     {
 241         sendDataAvailableNotification();
 242     }
 243
 244     return true;
 245 }
 246
 247 void IODataQueue::setNotificationPort(mach_port_t port)
 248 {
 249     mach_msg_header_t * msgh;
 250
 251     msgh = &((IODataQueueInternal *) notifyMsg)->msg;
 252         bzero(msgh, sizeof(mach_msg_header_t));
 253         msgh->msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
 254         msgh->msgh_size = sizeof(mach_msg_header_t);
 255         msgh->msgh_remote_port = port;
 256 }
 257
 258 void IODataQueue::sendDataAvailableNotification()
 259 {
 260     kern_return_t       kr;
 261     mach_msg_header_t * msgh;
 262
 263     msgh = &((IODataQueueInternal *) notifyMsg)->msg;
 264     if (msgh->msgh_remote_port) {
 265         kr = mach_msg_send_from_kernel_with_options(msgh, msgh->msgh_size, MACH_SEND_TIMEOUT, MACH_MSG_TIMEOUT_NONE);
 266         switch(kr) {
 267             case MACH_SEND_TIMED_OUT:    // Notification already sent
 268             case MACH_MSG_SUCCESS:
 269             case MACH_SEND_NO_BUFFER:
 270                 break;
 271             default:
 272                 IOLog("%s: dataAvailableNotification failed - msg_send returned: %d\n", /*getName()*/"IODataQueue", kr);
 273                 break;
 274         }
 275     }
 276 }
 277
 278 IOMemoryDescriptor *IODataQueue::getMemoryDescriptor()
 279 {
 280     IOMemoryDescriptor *descriptor = 0;
 281     UInt32              queueSize;
 282
 283     queueSize = ((IODataQueueInternal *) notifyMsg)->queueSize;
 284     if (dataQueue != 0) {
 285         descriptor = IOMemoryDescriptor::withAddress(dataQueue, queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE, kIODirectionOutIn);
 286     }
 287
 288     return descriptor;
 289 }
 290
 291