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,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
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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
 103     dataQueue->queueSize    = size;
 104     dataQueue->head         = 0;
 105     dataQueue->tail         = 0;
 106
 107     if (!notifyMsg) {
 108         notifyMsg = IOMalloc(sizeof(mach_msg_header_t));
 109         if (!notifyMsg)
 110             return false;
 111     }
 112     bzero(notifyMsg, sizeof(mach_msg_header_t));
 113
 114     return true;
 115 }
 116
 117 Boolean IODataQueue::initWithEntries(UInt32 numEntries, UInt32 entrySize)
 118 {
 119     // Checking overflow for (numEntries + 1)*(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE):
 120     //  check (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE)
 121     if ((entrySize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) ||
 122         //  check (numEntries + 1)
 123         (numEntries > UINT32_MAX-1) ||
 124         //  check (numEntries + 1)*(entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE)
 125         (entrySize + DATA_QUEUE_ENTRY_HEADER_SIZE > UINT32_MAX/(numEntries+1))) {
 126         return false;
 127     }
 128
 129     return (initWithCapacity((numEntries + 1) * (DATA_QUEUE_ENTRY_HEADER_SIZE + entrySize)));
 130 }
 131
 132 void IODataQueue::free()
 133 {
 134     if (dataQueue) {
 135         IOFreeAligned(dataQueue, round_page(dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE));
 136         dataQueue = NULL;
 137
 138         if (notifyMsg) {
 139             IOFree(notifyMsg, sizeof(mach_msg_header_t));
 140             notifyMsg = NULL;
 141         }
 142     }
 143
 144     super::free();
 145
 146     return;
 147 }
 148
 149 Boolean IODataQueue::enqueue(void * data, UInt32 dataSize)
 150 {
 151     const UInt32       head      = dataQueue->head;  // volatile
 152     const UInt32       tail      = dataQueue->tail;
 153     const UInt32       entrySize = dataSize + DATA_QUEUE_ENTRY_HEADER_SIZE;
 154     IODataQueueEntry * entry;
 155
 156     // Check for overflow of entrySize
 157     if (dataSize > UINT32_MAX - DATA_QUEUE_ENTRY_HEADER_SIZE) {
 158         return false;
 159     }
 160     // Check for underflow of (dataQueue->queueSize - tail)
 161     if (dataQueue->queueSize < tail) {
 162         return false;
 163     }
 164
 165     if ( tail >= head )
 166     {
 167         // Is there enough room at the end for the entry?
 168         if ((entrySize <= UINT32_MAX - tail) &&
 169             ((tail + entrySize) <= dataQueue->queueSize) )
 170         {
 171             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 172
 173             entry->size = dataSize;
 174             memcpy(&entry->data, data, dataSize);
 175
 176             // The tail can be out of bound when the size of the new entry
 177             // exactly matches the available space at the end of the queue.
 178             // The tail can range from 0 to dataQueue->queueSize inclusive.
 179
 180             OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
 181         }
 182         else if ( head > entrySize )     // Is there enough room at the beginning?
 183         {
 184             // Wrap around to the beginning, but do not allow the tail to catch
 185             // up to the head.
 186
 187             dataQueue->queue->size = dataSize;
 188
 189             // We need to make sure that there is enough room to set the size before
 190             // doing this. The user client checks for this and will look for the size
 191             // at the beginning if there isn't room for it at the end.
 192
 193             if ( ( dataQueue->queueSize - tail ) >= DATA_QUEUE_ENTRY_HEADER_SIZE )
 194             {
 195                 ((IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail))->size = dataSize;
 196             }
 197
 198             memcpy(&dataQueue->queue->data, data, dataSize);
 199             OSCompareAndSwap(dataQueue->tail, entrySize, &dataQueue->tail);
 200         }
 201         else
 202         {
 203             return false;    // queue is full
 204         }
 205     }
 206     else
 207     {
 208         // Do not allow the tail to catch up to the head when the queue is full.
 209         // That's why the comparison uses a '>' rather than '>='.
 210
 211         if ( (head - tail) > entrySize )
 212         {
 213             entry = (IODataQueueEntry *)((UInt8 *)dataQueue->queue + tail);
 214
 215             entry->size = dataSize;
 216             memcpy(&entry->data, data, dataSize);
 217             OSAddAtomic(entrySize, (SInt32 *)&dataQueue->tail);
 218         }
 219         else
 220         {
 221             return false;    // queue is full
 222         }
 223     }
 224
 225     // Send notification (via mach message) that data is available.
 226
 227     if ( ( head == tail )                                                   /* queue was empty prior to enqueue() */
 228     ||   ( dataQueue->head == tail ) )   /* queue was emptied during enqueue() */
 229     {
 230         sendDataAvailableNotification();
 231     }
 232
 233     return true;
 234 }
 235
 236 void IODataQueue::setNotificationPort(mach_port_t port)
 237 {
 238     mach_msg_header_t * msgh = (mach_msg_header_t *) notifyMsg;
 239
 240     if (msgh) {
 241         bzero(msgh, sizeof(mach_msg_header_t));
 242         msgh->msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0);
 243         msgh->msgh_size = sizeof(mach_msg_header_t);
 244         msgh->msgh_remote_port = port;
 245     }
 246 }
 247
 248 void IODataQueue::sendDataAvailableNotification()
 249 {
 250     kern_return_t       kr;
 251     mach_msg_header_t * msgh;
 252
 253     msgh = (mach_msg_header_t *) notifyMsg;
 254     if (msgh && msgh->msgh_remote_port) {
 255         kr = mach_msg_send_from_kernel_with_options(msgh, msgh->msgh_size, MACH_SEND_TIMEOUT, MACH_MSG_TIMEOUT_NONE);
 256         switch(kr) {
 257             case MACH_SEND_TIMED_OUT:    // Notification already sent
 258             case MACH_MSG_SUCCESS:
 259             case MACH_SEND_NO_BUFFER:
 260                 break;
 261             default:
 262                 IOLog("%s: dataAvailableNotification failed - msg_send returned: %d\n", /*getName()*/"IODataQueue", kr);
 263                 break;
 264         }
 265     }
 266 }
 267
 268 IOMemoryDescriptor *IODataQueue::getMemoryDescriptor()
 269 {
 270     IOMemoryDescriptor *descriptor = 0;
 271
 272     if (dataQueue != 0) {
 273         descriptor = IOMemoryDescriptor::withAddress(dataQueue, dataQueue->queueSize + DATA_QUEUE_MEMORY_HEADER_SIZE, kIODirectionOutIn);
 274     }
 275
 276     return descriptor;
 277 }
 278
 279