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