libkern/c++/OSObject.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* OSObject.cpp created by gvdl on Fri 1998-11-17 */
  23
  24 #include <libkern/c++/OSObject.h>
  25 #include <libkern/c++/OSSerialize.h>
  26 #include <libkern/c++/OSLib.h>
  27 #include <libkern/c++/OSCPPDebug.h>
  28 #include <libkern/OSAtomic.h>
  29
  30 #include <libkern/c++/OSCollection.h>
  31
  32 __BEGIN_DECLS
  33 int debug_ivars_size;
  34 __END_DECLS
  35
  36 #if OSALLOCDEBUG
  37 #define ACCUMSIZE(s) do { debug_ivars_size += (s); } while(0)
  38 #else
  39 #define ACCUMSIZE(s)
  40 #endif
  41
  42 // OSDefineMetaClassAndAbstractStructors(OSObject, 0);
  43 /* Class global data */
  44 OSObject::MetaClass OSObject::gMetaClass;
  45 const OSMetaClass * const OSObject::metaClass = &OSObject::gMetaClass;
  46 const OSMetaClass * const OSObject::superClass = 0;
  47
  48 /* Class member functions - Can't use defaults */
  49 OSObject::OSObject()                    { retainCount = 1; }
  50 OSObject::OSObject(const OSMetaClass *) { retainCount = 1; }
  51 OSObject::~OSObject()                   { }
  52 const OSMetaClass * OSObject::getMetaClass() const
  53     { return &gMetaClass; }
  54 OSObject *OSObject::MetaClass::alloc() const { return 0; }
  55
  56 /* The OSObject::MetaClass constructor */
  57 OSObject::MetaClass::MetaClass()
  58     : OSMetaClass("OSObject", OSObject::superClass, sizeof(OSObject))
  59     { }
  60
  61 // Virtual Padding
  62 OSMetaClassDefineReservedUnused(OSObject,  0);
  63 OSMetaClassDefineReservedUnused(OSObject,  1);
  64 OSMetaClassDefineReservedUnused(OSObject,  2);
  65 OSMetaClassDefineReservedUnused(OSObject,  3);
  66 OSMetaClassDefineReservedUnused(OSObject,  4);
  67 OSMetaClassDefineReservedUnused(OSObject,  5);
  68 OSMetaClassDefineReservedUnused(OSObject,  6);
  69 OSMetaClassDefineReservedUnused(OSObject,  7);
  70 OSMetaClassDefineReservedUnused(OSObject,  8);
  71 OSMetaClassDefineReservedUnused(OSObject,  9);
  72 OSMetaClassDefineReservedUnused(OSObject, 10);
  73 OSMetaClassDefineReservedUnused(OSObject, 11);
  74 OSMetaClassDefineReservedUnused(OSObject, 12);
  75 OSMetaClassDefineReservedUnused(OSObject, 13);
  76 OSMetaClassDefineReservedUnused(OSObject, 14);
  77 OSMetaClassDefineReservedUnused(OSObject, 15);
  78
  79 #ifdef __ppc__
  80 OSMetaClassDefineReservedUnused(OSObject, 16);
  81 OSMetaClassDefineReservedUnused(OSObject, 17);
  82 OSMetaClassDefineReservedUnused(OSObject, 18);
  83 OSMetaClassDefineReservedUnused(OSObject, 19);
  84 OSMetaClassDefineReservedUnused(OSObject, 20);
  85 OSMetaClassDefineReservedUnused(OSObject, 21);
  86 OSMetaClassDefineReservedUnused(OSObject, 22);
  87 OSMetaClassDefineReservedUnused(OSObject, 23);
  88 OSMetaClassDefineReservedUnused(OSObject, 24);
  89 OSMetaClassDefineReservedUnused(OSObject, 25);
  90 OSMetaClassDefineReservedUnused(OSObject, 26);
  91 OSMetaClassDefineReservedUnused(OSObject, 27);
  92 OSMetaClassDefineReservedUnused(OSObject, 28);
  93 OSMetaClassDefineReservedUnused(OSObject, 29);
  94 OSMetaClassDefineReservedUnused(OSObject, 30);
  95 OSMetaClassDefineReservedUnused(OSObject, 31);
  96 #endif
  97
  98 static const char *getClassName(const OSObject *obj)
  99 {
 100     const OSMetaClass *meta = obj->getMetaClass();
 101     return (meta) ? meta->getClassName() : "unknown class?";
 102 }
 103
 104 bool OSObject::init()
 105     { return true; }
 106
 107 #if (!__ppc__) || (__GNUC__ < 3)
 108
 109 // Implemented in assembler in post gcc 3.x systems as we have a problem
 110 // where the destructor in gcc2.95 gets 2 arguments.  The second argument
 111 // appears to be a flag argument.  I have copied the assembler from Puma xnu
 112 // to OSRuntimeSupport.c  So for 2.95 builds use the C
 113 void OSObject::free()
 114 {
 115     const OSMetaClass *meta = getMetaClass();
 116
 117     if (meta)
 118         meta->instanceDestructed();
 119     delete this;
 120 }
 121 #endif /* (!__ppc__) || (__GNUC__ < 3) */
 122
 123 int OSObject::getRetainCount() const
 124 {
 125     return (int) ((UInt16) retainCount);
 126 }
 127
 128 void OSObject::taggedRetain(const void *tag) const
 129 {
 130     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 131     UInt32 inc = 1;
 132     UInt32 origCount;
 133     UInt32 newCount;
 134
 135     // Increment the collection bucket.
 136     if ((const void *) OSTypeID(OSCollection) == tag)
 137         inc |= (1UL<<16);
 138
 139     do {
 140         origCount = *countP;
 141         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 142             const char *msg;
 143             if (origCount & 0x1) {
 144                 // If count == 0xffff that means we are freeing now so we can
 145                 // just return obviously somebody is cleaning up dangling
 146                 // references.
 147                 msg = "Attempting to retain a freed object";
 148             }
 149             else {
 150                 // If count == 0xfffe then we have wrapped our reference count.
 151                 // We should stop counting now as this reference must be
 152                 // leaked rather than accidently wrapping around the clock and
 153                 // freeing a very active object later.
 154
 155 #if !DEBUG
 156                 break;  // Break out of update loop which pegs the reference
 157 #else DEBUG
 158                 // @@@ gvdl: eventually need to make this panic optional
 159                 // based on a boot argument i.e. debug= boot flag
 160                 msg = "About to wrap the reference count, reference leak?";
 161 #endif /* !DEBUG */
 162             }
 163             panic("OSObject::refcount: %s", msg);
 164         }
 165
 166         newCount = origCount + inc;
 167     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 168 }
 169
 170 void OSObject::taggedRelease(const void *tag) const
 171 {
 172     taggedRelease(tag, 1);
 173 }
 174
 175 void OSObject::taggedRelease(const void *tag, const int when) const
 176 {
 177     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 178     UInt32 dec = 1;
 179     UInt32 origCount;
 180     UInt32 newCount;
 181     UInt32 actualCount;
 182
 183     // Increment the collection bucket.
 184     if ((const void *) OSTypeID(OSCollection) == tag)
 185         dec |= (1UL<<16);
 186
 187     do {
 188         origCount = *countP;
 189
 190         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 191             if (origCount & 0x1) {
 192                 // If count == 0xffff that means we are freeing now so we can
 193                 // just return obviously somebody is cleaning up some dangling
 194                 // references.  So we blow out immediately.
 195                 return;
 196             }
 197             else {
 198                 // If count == 0xfffe then we have wrapped our reference
 199                 // count.  We should stop counting now as this reference must be
 200                 // leaked rather than accidently freeing an active object later.
 201
 202 #if !DEBUG
 203                 return; // return out of function which pegs the reference
 204 #else DEBUG
 205                 // @@@ gvdl: eventually need to make this panic optional
 206                 // based on a boot argument i.e. debug= boot flag
 207                 panic("OSObject::refcount: %s",
 208                       "About to unreference a pegged object, reference leak?");
 209 #endif /* !DEBUG */
 210             }
 211         }
 212         actualCount = origCount - dec;
 213         if ((UInt16) actualCount < when)
 214             newCount = 0xffff;
 215         else
 216             newCount = actualCount;
 217
 218     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 219
 220     //
 221     // This panic means that we have just attempted to release an object
 222     // who's retain count has gone to less than the number of collections
 223     // it is a member off.  Take a panic immediately.
 224     // In Fact the panic MAY not be a registry corruption but it is
 225     // ALWAYS the wrong thing to do.  I call it a registry corruption 'cause
 226     // the registry is the biggest single use of a network of collections.
 227     //
 228     if ((UInt16) actualCount < (actualCount >> 16))
 229         panic("A driver releasing a(n) %s has corrupted the registry\n",
 230             getClassName(this));
 231
 232     // Check for a 'free' condition and that if we are first through
 233     if (newCount == 0xffff)
 234         ((OSObject *) this)->free();
 235 }
 236
 237 void OSObject::release() const
 238 {
 239     taggedRelease(0);
 240 }
 241
 242 void OSObject::retain() const
 243 {
 244     taggedRetain(0);
 245 }
 246
 247 void OSObject::release(int when) const
 248 {
 249     taggedRelease(0, when);
 250 }
 251
 252 bool OSObject::serialize(OSSerialize *s) const
 253 {
 254     if (s->previouslySerialized(this)) return true;
 255
 256     if (!s->addXMLStartTag(this, "string")) return false;
 257
 258     if (!s->addString(getClassName(this))) return false;
 259     if (!s->addString(" is not serializable")) return false;
 260
 261     return s->addXMLEndTag("string");
 262 }
 263
 264 void *OSObject::operator new(size_t size)
 265 {
 266     void *mem = (void *) kalloc(size);
 267     assert(mem);
 268     bzero(mem, size);
 269
 270     ACCUMSIZE(size);
 271
 272     return mem;
 273 }
 274
 275 void OSObject::operator delete(void *mem, size_t size)
 276 {
 277     kfree(mem, size);
 278
 279     ACCUMSIZE(-size);
 280 }