libkern/c++/OSObject.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /* OSObject.cpp created by gvdl on Fri 1998-11-17 */
  24
  25 #include <libkern/c++/OSObject.h>
  26 #include <libkern/c++/OSSerialize.h>
  27 #include <libkern/c++/OSLib.h>
  28 #include <libkern/c++/OSCPPDebug.h>
  29 #include <libkern/OSAtomic.h>
  30
  31 #include <libkern/c++/OSCollection.h>
  32
  33 __BEGIN_DECLS
  34 int debug_ivars_size;
  35 __END_DECLS
  36
  37 #if OSALLOCDEBUG
  38 #define ACCUMSIZE(s) do { debug_ivars_size += (s); } while(0)
  39 #else
  40 #define ACCUMSIZE(s)
  41 #endif
  42
  43 // OSDefineMetaClassAndAbstractStructors(OSObject, 0);
  44 /* Class global data */
  45 OSObject::MetaClass OSObject::gMetaClass;
  46 const OSMetaClass * const OSObject::metaClass = &OSObject::gMetaClass;
  47 const OSMetaClass * const OSObject::superClass = 0;
  48
  49 /* Class member functions - Can't use defaults */
  50 OSObject::OSObject()                    { retainCount = 1; }
  51 OSObject::OSObject(const OSMetaClass *) { retainCount = 1; }
  52 OSObject::~OSObject()                   { }
  53 const OSMetaClass * OSObject::getMetaClass() const
  54     { return &gMetaClass; }
  55 OSObject *OSObject::MetaClass::alloc() const { return 0; }
  56
  57 /* The OSObject::MetaClass constructor */
  58 OSObject::MetaClass::MetaClass()
  59     : OSMetaClass("OSObject", OSObject::superClass, sizeof(OSObject))
  60     { }
  61
  62 // Virtual Padding
  63 OSMetaClassDefineReservedUnused(OSObject,  0);
  64 OSMetaClassDefineReservedUnused(OSObject,  1);
  65 OSMetaClassDefineReservedUnused(OSObject,  2);
  66 OSMetaClassDefineReservedUnused(OSObject,  3);
  67 OSMetaClassDefineReservedUnused(OSObject,  4);
  68 OSMetaClassDefineReservedUnused(OSObject,  5);
  69 OSMetaClassDefineReservedUnused(OSObject,  6);
  70 OSMetaClassDefineReservedUnused(OSObject,  7);
  71 OSMetaClassDefineReservedUnused(OSObject,  8);
  72 OSMetaClassDefineReservedUnused(OSObject,  9);
  73 OSMetaClassDefineReservedUnused(OSObject, 10);
  74 OSMetaClassDefineReservedUnused(OSObject, 11);
  75 OSMetaClassDefineReservedUnused(OSObject, 12);
  76 OSMetaClassDefineReservedUnused(OSObject, 13);
  77 OSMetaClassDefineReservedUnused(OSObject, 14);
  78 OSMetaClassDefineReservedUnused(OSObject, 15);
  79 OSMetaClassDefineReservedUnused(OSObject, 16);
  80 OSMetaClassDefineReservedUnused(OSObject, 17);
  81 OSMetaClassDefineReservedUnused(OSObject, 18);
  82 OSMetaClassDefineReservedUnused(OSObject, 19);
  83 OSMetaClassDefineReservedUnused(OSObject, 20);
  84 OSMetaClassDefineReservedUnused(OSObject, 21);
  85 OSMetaClassDefineReservedUnused(OSObject, 22);
  86 OSMetaClassDefineReservedUnused(OSObject, 23);
  87 OSMetaClassDefineReservedUnused(OSObject, 24);
  88 OSMetaClassDefineReservedUnused(OSObject, 25);
  89 OSMetaClassDefineReservedUnused(OSObject, 26);
  90 OSMetaClassDefineReservedUnused(OSObject, 27);
  91 OSMetaClassDefineReservedUnused(OSObject, 28);
  92 OSMetaClassDefineReservedUnused(OSObject, 29);
  93 OSMetaClassDefineReservedUnused(OSObject, 30);
  94 OSMetaClassDefineReservedUnused(OSObject, 31);
  95
  96 static const char *getClassName(const OSObject *obj)
  97 {
  98     const OSMetaClass *meta = obj->getMetaClass();
  99     return (meta) ? meta->getClassName() : "unknown class?";
 100 }
 101
 102 bool OSObject::init()
 103     { return true; }
 104
 105 #if (!__ppc__) || (__GNUC__ < 3)
 106
 107 // Implemented in assembler in post gcc 3.x systems as we have a problem
 108 // where the destructor in gcc2.95 gets 2 arguments.  The second argument
 109 // appears to be a flag argument.  I have copied the assembler from Puma xnu
 110 // to OSRuntimeSupport.c  So for 2.95 builds use the C
 111 void OSObject::free()
 112 {
 113     const OSMetaClass *meta = getMetaClass();
 114
 115     if (meta)
 116         meta->instanceDestructed();
 117     delete this;
 118 }
 119 #endif /* (!__ppc__) || (__GNUC__ < 3) */
 120
 121 int OSObject::getRetainCount() const
 122 {
 123     return (int) ((UInt16) retainCount);
 124 }
 125
 126 void OSObject::taggedRetain(const void *tag) const
 127 {
 128     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 129     UInt32 inc = 1;
 130     UInt32 origCount;
 131     UInt32 newCount;
 132
 133     // Increment the collection bucket.
 134     if ((const void *) OSTypeID(OSCollection) == tag)
 135         inc |= (1UL<<16);
 136
 137     do {
 138         origCount = *countP;
 139         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 140             const char *msg;
 141             if (origCount & 0x1) {
 142                 // If count == 0xffff that means we are freeing now so we can
 143                 // just return obviously somebody is cleaning up dangling
 144                 // references.
 145                 msg = "Attempting to retain a freed object";
 146             }
 147             else {
 148                 // If count == 0xfffe then we have wrapped our reference count.
 149                 // We should stop counting now as this reference must be
 150                 // leaked rather than accidently wrapping around the clock and
 151                 // freeing a very active object later.
 152
 153 #if !DEBUG
 154                 break;  // Break out of update loop which pegs the reference
 155 #else DEBUG
 156                 // @@@ gvdl: eventually need to make this panic optional
 157                 // based on a boot argument i.e. debug= boot flag
 158                 msg = "About to wrap the reference count, reference leak?";
 159 #endif /* !DEBUG */
 160             }
 161             panic("OSObject::refcount: %s", msg);
 162         }
 163
 164         newCount = origCount + inc;
 165     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 166 }
 167
 168 void OSObject::taggedRelease(const void *tag) const
 169 {
 170     taggedRelease(tag, 1);
 171 }
 172
 173 void OSObject::taggedRelease(const void *tag, const int when) const
 174 {
 175     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 176     UInt32 dec = 1;
 177     UInt32 origCount;
 178     UInt32 newCount;
 179     UInt32 actualCount;
 180
 181     // Increment the collection bucket.
 182     if ((const void *) OSTypeID(OSCollection) == tag)
 183         dec |= (1UL<<16);
 184
 185     do {
 186         origCount = *countP;
 187
 188         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 189             if (origCount & 0x1) {
 190                 // If count == 0xffff that means we are freeing now so we can
 191                 // just return obviously somebody is cleaning up some dangling
 192                 // references.  So we blow out immediately.
 193                 return;
 194             }
 195             else {
 196                 // If count == 0xfffe then we have wrapped our reference
 197                 // count.  We should stop counting now as this reference must be
 198                 // leaked rather than accidently freeing an active object later.
 199
 200 #if !DEBUG
 201                 return; // return out of function which pegs the reference
 202 #else DEBUG
 203                 // @@@ gvdl: eventually need to make this panic optional
 204                 // based on a boot argument i.e. debug= boot flag
 205                 panic("OSObject::refcount: %s",
 206                       "About to unreference a pegged object, reference leak?");
 207 #endif /* !DEBUG */
 208             }
 209         }
 210         actualCount = origCount - dec;
 211         if ((UInt16) actualCount < when)
 212             newCount = 0xffff;
 213         else
 214             newCount = actualCount;
 215
 216     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 217
 218     //
 219     // This panic means that we have just attempted to release an object
 220     // who's retain count has gone to less than the number of collections
 221     // it is a member off.  Take a panic immediately.
 222     // In Fact the panic MAY not be a registry corruption but it is
 223     // ALWAYS the wrong thing to do.  I call it a registry corruption 'cause
 224     // the registry is the biggest single use of a network of collections.
 225     //
 226     if ((UInt16) actualCount < (actualCount >> 16))
 227         panic("A driver releasing a(n) %s has corrupted the registry\n",
 228             getClassName(this));
 229
 230     // Check for a 'free' condition and that if we are first through
 231     if (newCount == 0xffff)
 232         ((OSObject *) this)->free();
 233 }
 234
 235 void OSObject::release() const
 236 {
 237     taggedRelease(0);
 238 }
 239
 240 void OSObject::retain() const
 241 {
 242     taggedRetain(0);
 243 }
 244
 245 void OSObject::release(int when) const
 246 {
 247     taggedRelease(0, when);
 248 }
 249
 250 bool OSObject::serialize(OSSerialize *s) const
 251 {
 252     if (s->previouslySerialized(this)) return true;
 253
 254     if (!s->addXMLStartTag(this, "string")) return false;
 255
 256     if (!s->addString(getClassName(this))) return false;
 257     if (!s->addString(" is not serializable")) return false;
 258
 259     return s->addXMLEndTag("string");
 260 }
 261
 262 void *OSObject::operator new(size_t size)
 263 {
 264     void *mem = (void *) kalloc(size);
 265     assert(mem);
 266     bzero(mem, size);
 267
 268     ACCUMSIZE(size);
 269
 270     return mem;
 271 }
 272
 273 void OSObject::operator delete(void *mem, size_t size)
 274 {
 275     kfree((vm_offset_t) mem, size);
 276
 277     ACCUMSIZE(-size);
 278 }