iokit/Kernel/IOSharedDataQueue.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  10  * may not be used to create, or enable the creation or redistribution of,
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  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 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     UInt32            headOffset;
 162     UInt32            tailOffset;
 163
 164     if (!dataQueue) {
 165         return NULL;
 166     }
 167
 168     // Read head and tail with acquire barrier
 169     headOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_RELAXED);
 170     tailOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->tail, __ATOMIC_ACQUIRE);
 171
 172     if (headOffset != tailOffset) {
 173         IODataQueueEntry *  head        = 0;
 174         UInt32              headSize    = 0;
 175         UInt32              headOffset  = dataQueue->head;
 176         UInt32              queueSize   = getQueueSize();
 177
 178         if (headOffset >= queueSize) {
 179             return NULL;
 180         }
 181
 182         head         = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
 183         headSize     = head->size;
 184
 185         // Check if there's enough room before the end of the queue for a header.
 186         // If there is room, check if there's enough room to hold the header and
 187         // the data.
 188
 189         if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 190             (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
 191             (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
 192             (headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
 193             // No room for the header or the data, wrap to the beginning of the queue.
 194             // Note: wrapping even with the UINT32_MAX checks, as we have to support
 195             // queueSize of UINT32_MAX
 196             entry = dataQueue->queue;
 197         } else {
 198             entry = head;
 199         }
 200     }
 201
 202     return entry;
 203 }
 204
 205 Boolean IOSharedDataQueue::enqueue(void * data, UInt32 dataSize)
 206 {
 207     UInt32             head;
 208     UInt32             tail;
 209     UInt32             newTail;
 210     const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 211     IODataQueueEntry * entry;
 212
 213     // Force a single read of head and tail
 214     head = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_RELAXED);
 215     tail = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->tail, __ATOMIC_RELAXED);
 216
 217     // Check for overflow of entrySize
 218     if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
 219         return false;
 220     }
 221     // Check for underflow of (getQueueSize() - tail)
 222     if (getQueueSize() < tail || getQueueSize() < head) {
 223         return false;
 224     }
 225
 226     if ( tail >= head )
 227     {
 228         // Is there enough room at the end for the entry?
 229         if ((entrySize <= UINT32_MAX - tail) &&
 230             ((tail + entrySize) <= getQueueSize()) )
 231         {
 232             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 233
 234             entry->size = dataSize;
 235             memcpy(&entry->data, data, dataSize);
 236
 237             // The tail can be out of bound when the size of the new entry
 238             // exactly matches the available space at the end of the queue.
 239             // The tail can range from 0 to dataQueue->queueSize inclusive.
 240
 241             newTail = tail + entrySize;
 242         }
 243         else if ( head > entrySize )     // Is there enough room at the beginning?
 244         {
 245             // Wrap around to the beginning, but do not allow the tail to catch
 246             // up to the head.
 247
 248             dataQueue->queue->size = dataSize;
 249
 250             // We need to make sure that there is enough room to set the size before
 251             // doing this. The user client checks for this and will look for the size
 252             // at the beginning if there isn't room for it at the end.
 253
 254             if ( ( getQueueSize() - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
 255             {
 256                 ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
 257             }
 258
 259             memcpy(&dataQueue->queue->data, data, dataSize);
 260             newTail = entrySize;
 261         }
 262         else
 263         {
 264             return false;    // queue is full
 265         }
 266     }
 267     else
 268     {
 269         // Do not allow the tail to catch up to the head when the queue is full.
 270         // That's why the comparison uses a '>' rather than '>='.
 271
 272         if ( (head - tail) > entrySize )
 273         {
 274             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 275
 276             entry->size = dataSize;
 277             memcpy(&entry->data, data, dataSize);
 278             newTail = tail + entrySize;
 279         }
 280         else
 281         {
 282             return false;    // queue is full
 283         }
 284     }
 285
 286     // Update tail with release barrier
 287     __c11_atomic_store((_Atomic UInt32 *)&dataQueue->tail, newTail, __ATOMIC_RELEASE);
 288
 289     // Send notification (via mach message) that data is available.
 290
 291     if ( ( tail == head )                                                   /* queue was empty prior to enqueue() */
 292       || ( tail == __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_RELAXED) ) )   /* queue was emptied during enqueue() */
 293     {
 294         sendDataAvailableNotification();
 295     }
 296
 297     return true;
 298 }
 299
 300 Boolean IOSharedDataQueue::dequeue(void *data, UInt32 *dataSize)
 301 {
 302     Boolean             retVal          = TRUE;
 303     IODataQueueEntry *  entry           = 0;
 304     UInt32              entrySize       = 0;
 305     UInt32              headOffset      = 0;
 306     UInt32              tailOffset      = 0;
 307     UInt32              newHeadOffset   = 0;
 308
 309     if (!dataQueue) {
 310         return false;
 311     }
 312
 313     // Read head and tail with acquire barrier
 314     tailOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->tail, __ATOMIC_RELAXED);
 315     headOffset = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_ACQUIRE);
 316
 317     if (headOffset != tailOffset) {
 318         IODataQueueEntry *  head        = 0;
 319         UInt32              headSize    = 0;
 320         UInt32              queueSize   = getQueueSize();
 321
 322         if (headOffset > queueSize) {
 323             return false;
 324         }
 325
 326         head         = (IODataQueueEntry *)((char *)dataQueue->queue + headOffset);
 327         headSize     = head->size;
 328
 329         // we wrapped around to beginning, so read from there
 330         // either there was not even room for the header
 331         if ((headOffset > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 332             (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize) ||
 333             // or there was room for the header, but not for the data
 334             (headOffset + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headSize) ||
 335             (headOffset + headSize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
 336             // Note: we have to wrap to the beginning even with the UINT32_MAX checks
 337             // because we have to support a queueSize of UINT32_MAX.
 338             entry           = dataQueue->queue;
 339             entrySize       = entry->size;
 340             if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 341                 (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > queueSize)) {
 342                 return false;
 343             }
 344             newHeadOffset   = entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 345             // else it is at the end
 346         } else {
 347             entry           = head;
 348             entrySize       = entry->size;
 349             if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 350                 (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX - headOffset) ||
 351                 (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE + headOffset > queueSize)) {
 352                 return false;
 353             }
 354             newHeadOffset   = headOffset + entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 355         }
 356     }
 357
 358     if (entry) {
 359         if (data) {
 360             if (dataSize) {
 361                 if (entrySize <= *dataSize) {
 362                     memcpy(data, &(entry->data), entrySize);
 363                     __c11_atomic_store((_Atomic UInt32 *)&dataQueue->head, newHeadOffset, __ATOMIC_RELEASE);
 364                 } else {
 365                     retVal = FALSE;
 366                 }
 367             } else {
 368                 retVal = FALSE;
 369             }
 370         } else {
 371             __c11_atomic_store((_Atomic UInt32 *)&dataQueue->head, newHeadOffset, __ATOMIC_RELEASE);
 372         }
 373
 374         if (dataSize) {
 375             *dataSize = entrySize;
 376         }
 377     } else {
 378         retVal = FALSE;
 379     }
 380
 381     return retVal;
 382 }
 383
 384 UInt32 IOSharedDataQueue::getQueueSize()
 385 {
 386     if (!_reserved) {
 387         return 0;
 388     }
 389     return _reserved->queueSize;
 390 }
 391
 392 Boolean IOSharedDataQueue::setQueueSize(UInt32 size)
 393 {
 394     if (!_reserved) {
 395         return false;
 396     }
 397     _reserved->queueSize = size;
 398     return true;
 399 }
 400
 401 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 0);
 402 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 1);
 403 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 2);
 404 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 3);
 405 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 4);
 406 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 5);
 407 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 6);
 408 OSMetaClassDefineReservedUnused(IOSharedDataQueue, 7);