iokit/Kernel/IODataQueue.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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   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.
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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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  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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  23  * Please see the License for the specific language governing rights and
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  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     UInt32             head;
 160     UInt32             tail;
 161     UInt32             newTail;
 162     const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 163     UInt32             queueSize;
 164     IODataQueueEntry * entry;
 165
 166     // Check for overflow of entrySize
 167     if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
 168         return false;
 169     }
 170
 171     // Force a single read of head and tail
 172     // See rdar://problem/40780584 for an explanation of relaxed/acquire barriers
 173     tail = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->tail, __ATOMIC_RELAXED);
 174     head = __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_ACQUIRE);
 175
 176     // Check for underflow of (dataQueue->queueSize - tail)
 177     queueSize = ((IODataQueueInternal *) notifyMsg)->queueSize;
 178     if ((queueSize < tail) || (queueSize < head)) {
 179         return false;
 180     }
 181
 182     if ( tail >= head )
 183     {
 184         // Is there enough room at the end for the entry?
 185         if ((entrySize <= UINT32_MAX - tail) &&
 186             ((tail + entrySize) <= queueSize) )
 187         {
 188             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 189
 190             entry->size = dataSize;
 191             memcpy(&entry->data, data, dataSize);
 192
 193             // The tail can be out of bound when the size of the new entry
 194             // exactly matches the available space at the end of the queue.
 195             // The tail can range from 0 to dataQueue->queueSize inclusive.
 196
 197             newTail = tail + entrySize;
 198         }
 199         else if ( head > entrySize )     // Is there enough room at the beginning?
 200         {
 201             // Wrap around to the beginning, but do not allow the tail to catch
 202             // up to the head.
 203
 204             dataQueue->queue->size = dataSize;
 205
 206             // We need to make sure that there is enough room to set the size before
 207             // doing this. The user client checks for this and will look for the size
 208             // at the beginning if there isn't room for it at the end.
 209
 210             if ( ( queueSize - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
 211             {
 212                 ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
 213             }
 214
 215             memcpy(&dataQueue->queue->data, data, dataSize);
 216             newTail = entrySize;
 217         }
 218         else
 219         {
 220             return false;    // queue is full
 221         }
 222     }
 223     else
 224     {
 225         // Do not allow the tail to catch up to the head when the queue is full.
 226         // That's why the comparison uses a '>' rather than '>='.
 227
 228         if ( (head - tail) > entrySize )
 229         {
 230             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 231
 232             entry->size = dataSize;
 233             memcpy(&entry->data, data, dataSize);
 234             newTail = tail + entrySize;
 235         }
 236         else
 237         {
 238             return false;    // queue is full
 239         }
 240     }
 241
 242     // Store tail with a release memory barrier
 243     __c11_atomic_store((_Atomic UInt32 *)&dataQueue->tail, newTail, __ATOMIC_RELEASE);
 244
 245     // Send notification (via mach message) that data is available.
 246
 247     if ( ( head == tail )                /* queue was empty prior to enqueue() */
 248     ||   ( tail == __c11_atomic_load((_Atomic UInt32 *)&dataQueue->head, __ATOMIC_ACQUIRE) ) )   /* queue was emptied during enqueue() */
 249     {
 250         sendDataAvailableNotification();
 251     }
 252
 253     return true;
 254 }
 255
 256 void IODataQueue::setNotificationPort(mach_port_t port)
 257 {
 258     mach_msg_header_t * msgh;
 259
 260     msgh = &((IODataQueueInternal *) notifyMsg)->msg;
 261         bzero(msgh, sizeof(mach_msg_header_t));
 262         msgh->msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
 263         msgh->msgh_size = sizeof(mach_msg_header_t);
 264         msgh->msgh_remote_port = port;
 265 }
 266
 267 void IODataQueue::sendDataAvailableNotification()
 268 {
 269     kern_return_t       kr;
 270     mach_msg_header_t * msgh;
 271
 272     msgh = &((IODataQueueInternal *) notifyMsg)->msg;
 273     if (msgh->msgh_remote_port) {
 274         kr = mach_msg_send_from_kernel_with_options(msgh, msgh->msgh_size, MACH_SEND_TIMEOUT, MACH_MSG_TIMEOUT_NONE);
 275         switch(kr) {
 276             case MACH_SEND_TIMED_OUT:    // Notification already sent
 277             case MACH_MSG_SUCCESS:
 278             case MACH_SEND_NO_BUFFER:
 279                 break;
 280             default:
 281                 IOLog("%s: dataAvailableNotification failed - msg_send returned: %d\n", /*getName()*/"IODataQueue", kr);
 282                 break;
 283         }
 284     }
 285 }
 286
 287 IOMemoryDescriptor *IODataQueue::getMemoryDescriptor()
 288 {
 289     IOMemoryDescriptor *descriptor = 0;
 290     UInt32              queueSize;
 291
 292     queueSize = ((IODataQueueInternal *) notifyMsg)->queueSize;
 293     if (dataQueue != 0) {
 294         descriptor = IOMemoryDescriptor::withAddress(dataQueue, queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE, kIODirectionOutIn);
 295     }
 296
 297     return descriptor;
 298 }
 299
 300