iokit/Kernel/IOSharedDataQueue.cpp

   1 /*
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  28
  29 #include <IOKit/IOSharedDataQueue.h>
  30 #include <IOKit/IODataQueueShared.h>
  31 #include <IOKit/IOLib.h>
  32 #include <IOKit/IOMemoryDescriptor.h>
  33
  34 #ifdef enqueue
  35 #undef enqueue
  36 #endif
  37
  38 #ifdef dequeue
  39 #undef dequeue
  40 #endif
  41
  42 #define super IODataQueue
  43
  44 OSDefineMetaClassAndStructors(IOSharedDataQueue, IODataQueue)
  45
  46 IOSharedDataQueue *IOSharedDataQueue::withCapacity(UInt32 size)
  47 {
  48     IOSharedDataQueue *dataQueue = new IOSharedDataQueue;
  49
  50     if (dataQueue) {
  51         if  (!dataQueue->initWithCapacity(size)) {
  52             dataQueue->release();
  53             dataQueue = 0;
  54         }
  55     }
  56
  57     return dataQueue;
  58 }
  59
  60 IOSharedDataQueue *IOSharedDataQueue::withEntries(UInt32 numEntries, UInt32 entrySize)
  61 {
  62     IOSharedDataQueue *dataQueue = new IOSharedDataQueue;
  63
  64     if (dataQueue) {
  65         if (!dataQueue->initWithEntries(numEntries, entrySize)) {
  66             dataQueue->release();
  67             dataQueue = 0;
  68         }
  69     }
  70
  71     return dataQueue;
  72 }
  73
  74 Boolean IOSharedDataQueue::initWithCapacity(UInt32 size)
  75 {
  76     IODataQueueAppendix *   appendix;
  77     vm_size_t               allocSize;
  78
  79     if (!super::init()) {
  80         return false;
  81     }
  82
  83     _reserved = (ExpansionData *)IOMalloc(sizeof(struct ExpansionData));
  84     if (!_reserved) {
  85         return false;
  86     }
  87
  88     if (size > UINT32_MAX - DATA_QUEUE_MEMORY_HEADER_SIZE - DATA_QUEUE_MEMORY_APPENDIX_SIZE) {
  89         return false;
  90     }
  91
  92     allocSize = round_page(size + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE);
  93
  94     if (allocSize < size) {
  95         return false;
  96     }
  97
  98     dataQueue = (IODataQueueMemory *)IOMallocAligned(allocSize, PAGE_SIZE);
  99     if (dataQueue == 0) {
 100         return false;
 101     }
 102     bzero(dataQueue, allocSize);
 103
 104     dataQueue->queueSize    = size;
 105 //  dataQueue->head         = 0;
 106 //  dataQueue->tail         = 0;
 107
 108     if (!setQueueSize(size)) {
 109         return false;
 110     }
 111
 112     appendix            = (IODataQueueAppendix *)((UInt8 *)dataQueue + size + DATA_QUEUE_MEMORY_HEADER_SIZE);
 113     appendix->version   = 0;
 114
 115     if (!notifyMsg) {
 116         notifyMsg = IOMalloc(sizeof(mach_msg_header_t));
 117         if (!notifyMsg)
 118             return false;
 119     }
 120     bzero(notifyMsg, sizeof(mach_msg_header_t));
 121
 122     setNotificationPort(MACH_PORT_NULL);
 123
 124     return true;
 125 }
 126
 127 void IOSharedDataQueue::free()
 128 {
 129     if (dataQueue) {
 130         IOFreeAligned(dataQueue, round_page(getQueueSize() + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE));
 131         dataQueue = NULL;
 132         if (notifyMsg) {
 133             IOFree(notifyMsg, sizeof(mach_msg_header_t));
 134             notifyMsg = NULL;
 135         }
 136     }
 137
 138     if (_reserved) {
 139         IOFree (_reserved, sizeof(struct ExpansionData));
 140         _reserved = NULL;
 141     }
 142
 143     super::free();
 144 }
 145
 146 IOMemoryDescriptor *IOSharedDataQueue::getMemoryDescriptor()
 147 {
 148     IOMemoryDescriptor *descriptor = 0;
 149
 150     if (dataQueue != 0) {
 151         descriptor = IOMemoryDescriptor::withAddress(dataQueue, getQueueSize() + DATA_QUEUE_MEMORY_HEADER_SIZE + DATA_QUEUE_MEMORY_APPENDIX_SIZE, kIODirectionOutIn);
 152     }
 153
 154     return descriptor;
 155 }
 156
 157
 158 IODataQueueEntry * IOSharedDataQueue::peek()
 159 {
 160     IODataQueueEntry *entry = 0;
 161
 162     if (dataQueue && (dataQueue->head != dataQueue->tail)) {
 163         IODataQueueEntry *  head        = 0;
 164         UInt32              headSize    = 0;
 165         UInt32              headOffset  = dataQueue->head;
 166         UInt32              queueSize   = getQueueSize();
 167
 168         if (headOffset >= queueSize) {
 169             return NULL;
 170         }
 171
 172         head         = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
 173         headSize     = head->size;
 174
 175         // Check if there's enough room before the end of the queue for a header.
 176         // If there is room, check if there's enough room to hold the header and
 177         // the data.
 178
 179         if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 180             (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
 181             (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
 182             (headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
 183             // No room for the header or the data, wrap to the beginning of the queue.
 184             // Note: wrapping even with the UINT32_MAX checks, as we have to support
 185             // queueSize of UINT32_MAX
 186             entry = dataQueue->queue;
 187         } else {
 188             entry = head;
 189         }
 190     }
 191
 192     return entry;
 193 }
 194
 195 Boolean IOSharedDataQueue::enqueue(void * data, UInt32 dataSize)
 196 {
 197     const UInt32       head      = dataQueue->head;  // volatile
 198     const UInt32       tail      = dataQueue->tail;
 199     const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 200     IODataQueueEntry * entry;
 201
 202     // Check for overflow of entrySize
 203     if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
 204         return false;
 205     }
 206     // Check for underflow of (getQueueSize() - tail)
 207     if (getQueueSize() < tail || getQueueSize() < head) {
 208         return false;
 209     }
 210
 211     if ( tail >= head )
 212     {
 213         // Is there enough room at the end for the entry?
 214         if ((entrySize <= UINT32_MAX - tail) &&
 215             ((tail + entrySize) <= getQueueSize()) )
 216         {
 217             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 218
 219             entry->size = dataSize;
 220             memcpy(&entry->data, data, dataSize);
 221
 222             // The tail can be out of bound when the size of the new entry
 223             // exactly matches the available space at the end of the queue.
 224             // The tail can range from 0 to dataQueue->queueSize inclusive.
 225
 226             OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
 227         }
 228         else if ( head > entrySize )     // Is there enough room at the beginning?
 229         {
 230             // Wrap around to the beginning, but do not allow the tail to catch
 231             // up to the head.
 232
 233             dataQueue->queue->size = dataSize;
 234
 235             // We need to make sure that there is enough room to set the size before
 236             // doing this. The user client checks for this and will look for the size
 237             // at the beginning if there isn't room for it at the end.
 238
 239             if ( ( getQueueSize() - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
 240             {
 241                 ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
 242             }
 243
 244             memcpy(&dataQueue->queue->data, data, dataSize);
 245             OSCompareAndSwap(dataQueue->tail, entrySize, &dataQueue->tail);
 246         }
 247         else
 248         {
 249             return false;    // queue is full
 250         }
 251     }
 252     else
 253     {
 254         // Do not allow the tail to catch up to the head when the queue is full.
 255         // That's why the comparison uses a '>' rather than '>='.
 256
 257         if ( (head - tail) > entrySize )
 258         {
 259             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 260
 261             entry->size = dataSize;
 262             memcpy(&entry->data, data, dataSize);
 263             OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
 264         }
 265         else
 266         {
 267             return false;    // queue is full
 268         }
 269     }
 270
 271     // Send notification (via mach message) that data is available.
 272
 273     if ( ( head == tail )                                                   /* queue was empty prior to enqueue() */
 274         ||   ( dataQueue->head == tail ) )   /* queue was emptied during enqueue() */
 275     {
 276         sendDataAvailableNotification();
 277     }
 278
 279     return true;
 280 }
 281
 282 Boolean IOSharedDataQueue::dequeue(void *data, UInt32 *dataSize)
 283 {
 284     Boolean             retVal          = TRUE;
 285     IODataQueueEntry *  entry           = 0;
 286     UInt32              entrySize       = 0;
 287     UInt32              newHeadOffset   = 0;
 288
 289     if (dataQueue) {
 290         if (dataQueue->head != dataQueue->tail) {
 291             IODataQueueEntry *  head        = 0;
 292             UInt32              headSize    = 0;
 293             UInt32              headOffset  = dataQueue->head;
 294             UInt32              queueSize   = getQueueSize();
 295
 296             if (headOffset > queueSize) {
 297                 return false;
 298             }
 299
 300             head         = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
 301             headSize     = head->size;
 302
 303             // we wrapped around to beginning, so read from there
 304             // either there was not even room for the header
 305             if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 306                 (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
 307                 // or there was room for the header, but not for the data
 308                 (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
 309                 (headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
 310                 // Note: we have to wrap to the beginning even with the UINT32_MAX checks
 311                 // because we have to support a queueSize of UINT32_MAX.
 312                 entry           = dataQueue->queue;
 313                 entrySize       = entry->size;
 314                 if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 315                     (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
 316                     return false;
 317                 }
 318                 newHeadOffset   = entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 319                 // else it is at the end
 320             } else {
 321                 entry           = head;
 322                 entrySize       = entry->size;
 323                 if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 324                     (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headOffset) ||
 325                     (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE + headOffset > queueSize)) {
 326                     return false;
 327                 }
 328                 newHeadOffset   = headOffset + entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 329             }
 330         }
 331
 332         if (entry) {
 333             if (data) {
 334                 if (dataSize) {
 335                     if (entrySize <= *dataSize) {
 336                         memcpy(data, &(entry->data), entrySize);
 337                         OSCompareAndSwap( dataQueue->head, newHeadOffset, (SInt32 *)&dataQueue->head);
 338                     } else {
 339                         retVal = FALSE;
 340                     }
 341                 } else {
 342                     retVal = FALSE;
 343                 }
 344             } else {
 345                 OSCompareAndSwap( dataQueue->head, newHeadOffset, (SInt32 *)&dataQueue->head);
 346             }
 347
 348             if (dataSize) {
 349                 *dataSize = entrySize;
 350             }
 351         } else {
 352             retVal = FALSE;
 353         }
 354     } else {
 355         retVal = FALSE;
 356     }
 357
 358     return retVal;
 359 }
 360
 361 UInt32 IOSharedDataQueue::getQueueSize()
 362 {
 363     if (!_reserved) {
 364         return 0;
 365     }
 366     return _reserved->queueSize;
 367 }
 368
 369 Boolean IOSharedDataQueue::setQueueSize(UInt32 size)
 370 {
 371     if (!_reserved) {
 372         return false;
 373     }
 374     _reserved->queueSize = size;
 375     return true;
 376 }
 377
 378 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 0);
 379 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 1);
 380 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 2);
 381 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 3);
 382 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 4);
 383 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 5);
 384 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 6);
 385 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 7);