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 OSMetaClassDefineReservedUnused(OSObject, 16);
  79 OSMetaClassDefineReservedUnused(OSObject, 17);
  80 OSMetaClassDefineReservedUnused(OSObject, 18);
  81 OSMetaClassDefineReservedUnused(OSObject, 19);
  82 OSMetaClassDefineReservedUnused(OSObject, 20);
  83 OSMetaClassDefineReservedUnused(OSObject, 21);
  84 OSMetaClassDefineReservedUnused(OSObject, 22);
  85 OSMetaClassDefineReservedUnused(OSObject, 23);
  86 OSMetaClassDefineReservedUnused(OSObject, 24);
  87 OSMetaClassDefineReservedUnused(OSObject, 25);
  88 OSMetaClassDefineReservedUnused(OSObject, 26);
  89 OSMetaClassDefineReservedUnused(OSObject, 27);
  90 OSMetaClassDefineReservedUnused(OSObject, 28);
  91 OSMetaClassDefineReservedUnused(OSObject, 29);
  92 OSMetaClassDefineReservedUnused(OSObject, 30);
  93 OSMetaClassDefineReservedUnused(OSObject, 31);
  94
  95 static const char *getClassName(const OSObject *obj)
  96 {
  97     const OSMetaClass *meta = obj->getMetaClass();
  98     return (meta) ? meta->getClassName() : "unknown class?";
  99 }
 100
 101 bool OSObject::init()
 102     { return true; }
 103
 104 #if (!__ppc__) || (__GNUC__ < 3)
 105
 106 // Implemented in assembler in post gcc 3.x systems as we have a problem
 107 // where the destructor in gcc2.95 gets 2 arguments.  The second argument
 108 // appears to be a flag argument.  I have copied the assembler from Puma xnu
 109 // to OSRuntimeSupport.c  So for 2.95 builds use the C
 110 void OSObject::free()
 111 {
 112     const OSMetaClass *meta = getMetaClass();
 113
 114     if (meta)
 115         meta->instanceDestructed();
 116     delete this;
 117 }
 118 #endif /* (!__ppc__) || (__GNUC__ < 3) */
 119
 120 int OSObject::getRetainCount() const
 121 {
 122     return (int) ((UInt16) retainCount);
 123 }
 124
 125 void OSObject::taggedRetain(const void *tag) const
 126 {
 127     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 128     UInt32 inc = 1;
 129     UInt32 origCount;
 130     UInt32 newCount;
 131
 132     // Increment the collection bucket.
 133     if ((const void *) OSTypeID(OSCollection) == tag)
 134         inc |= (1UL<<16);
 135
 136     do {
 137         origCount = *countP;
 138         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 139             const char *msg;
 140             if (origCount & 0x1) {
 141                 // If count == 0xffff that means we are freeing now so we can
 142                 // just return obviously somebody is cleaning up dangling
 143                 // references.
 144                 msg = "Attempting to retain a freed object";
 145             }
 146             else {
 147                 // If count == 0xfffe then we have wrapped our reference count.
 148                 // We should stop counting now as this reference must be
 149                 // leaked rather than accidently wrapping around the clock and
 150                 // freeing a very active object later.
 151
 152 #if !DEBUG
 153                 break;  // Break out of update loop which pegs the reference
 154 #else DEBUG
 155                 // @@@ gvdl: eventually need to make this panic optional
 156                 // based on a boot argument i.e. debug= boot flag
 157                 msg = "About to wrap the reference count, reference leak?";
 158 #endif /* !DEBUG */
 159             }
 160             panic("OSObject::refcount: %s", msg);
 161         }
 162
 163         newCount = origCount + inc;
 164     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 165 }
 166
 167 void OSObject::taggedRelease(const void *tag) const
 168 {
 169     taggedRelease(tag, 1);
 170 }
 171
 172 void OSObject::taggedRelease(const void *tag, const int when) const
 173 {
 174     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 175     UInt32 dec = 1;
 176     UInt32 origCount;
 177     UInt32 newCount;
 178     UInt32 actualCount;
 179
 180     // Increment the collection bucket.
 181     if ((const void *) OSTypeID(OSCollection) == tag)
 182         dec |= (1UL<<16);
 183
 184     do {
 185         origCount = *countP;
 186
 187         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 188             if (origCount & 0x1) {
 189                 // If count == 0xffff that means we are freeing now so we can
 190                 // just return obviously somebody is cleaning up some dangling
 191                 // references.  So we blow out immediately.
 192                 return;
 193             }
 194             else {
 195                 // If count == 0xfffe then we have wrapped our reference
 196                 // count.  We should stop counting now as this reference must be
 197                 // leaked rather than accidently freeing an active object later.
 198
 199 #if !DEBUG
 200                 return; // return out of function which pegs the reference
 201 #else DEBUG
 202                 // @@@ gvdl: eventually need to make this panic optional
 203                 // based on a boot argument i.e. debug= boot flag
 204                 panic("OSObject::refcount: %s",
 205                       "About to unreference a pegged object, reference leak?");
 206 #endif /* !DEBUG */
 207             }
 208         }
 209         actualCount = origCount - dec;
 210         if ((UInt16) actualCount < when)
 211             newCount = 0xffff;
 212         else
 213             newCount = actualCount;
 214
 215     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 216
 217     //
 218     // This panic means that we have just attempted to release an object
 219     // who's retain count has gone to less than the number of collections
 220     // it is a member off.  Take a panic immediately.
 221     // In Fact the panic MAY not be a registry corruption but it is
 222     // ALWAYS the wrong thing to do.  I call it a registry corruption 'cause
 223     // the registry is the biggest single use of a network of collections.
 224     //
 225     if ((UInt16) actualCount < (actualCount >> 16))
 226         panic("A driver releasing a(n) %s has corrupted the registry\n",
 227             getClassName(this));
 228
 229     // Check for a 'free' condition and that if we are first through
 230     if (newCount == 0xffff)
 231         ((OSObject *) this)->free();
 232 }
 233
 234 void OSObject::release() const
 235 {
 236     taggedRelease(0);
 237 }
 238
 239 void OSObject::retain() const
 240 {
 241     taggedRetain(0);
 242 }
 243
 244 void OSObject::release(int when) const
 245 {
 246     taggedRelease(0, when);
 247 }
 248
 249 bool OSObject::serialize(OSSerialize *s) const
 250 {
 251     if (s->previouslySerialized(this)) return true;
 252
 253     if (!s->addXMLStartTag(this, "string")) return false;
 254
 255     if (!s->addString(getClassName(this))) return false;
 256     if (!s->addString(" is not serializable")) return false;
 257
 258     return s->addXMLEndTag("string");
 259 }
 260
 261 void *OSObject::operator new(size_t size)
 262 {
 263     void *mem = (void *) kalloc(size);
 264     assert(mem);
 265     bzero(mem, size);
 266
 267     ACCUMSIZE(size);
 268
 269     return mem;
 270 }
 271
 272 void OSObject::operator delete(void *mem, size_t size)
 273 {
 274     kfree((vm_offset_t) mem, size);
 275
 276     ACCUMSIZE(-size);
 277 }