libkern/c++/OSObject.cpp

   1 /*
   2  * Copyright (c) 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,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* OSObject.cpp created by gvdl on Fri 1998-11-17 */
  29
  30 #include <libkern/c++/OSObject.h>
  31 #include <libkern/c++/OSSerialize.h>
  32 #include <libkern/c++/OSLib.h>
  33 #include <libkern/c++/OSCPPDebug.h>
  34 #include <libkern/OSAtomic.h>
  35
  36 #include <libkern/c++/OSCollection.h>
  37
  38 __BEGIN_DECLS
  39 int debug_ivars_size;
  40 __END_DECLS
  41
  42 #if OSALLOCDEBUG
  43 #define ACCUMSIZE(s) do { debug_ivars_size += (s); } while(0)
  44 #else
  45 #define ACCUMSIZE(s)
  46 #endif
  47
  48 // OSDefineMetaClassAndAbstractStructors(OSObject, 0);
  49 /* Class global data */
  50 OSObject::MetaClass OSObject::gMetaClass;
  51 const OSMetaClass * const OSObject::metaClass = &OSObject::gMetaClass;
  52 const OSMetaClass * const OSObject::superClass = 0;
  53
  54 /* Class member functions - Can't use defaults */
  55 OSObject::OSObject()                    { retainCount = 1; }
  56 OSObject::OSObject(const OSMetaClass *) { retainCount = 1; }
  57 OSObject::~OSObject()                   { }
  58 const OSMetaClass * OSObject::getMetaClass() const
  59     { return &gMetaClass; }
  60 OSObject *OSObject::MetaClass::alloc() const { return 0; }
  61
  62 /* The OSObject::MetaClass constructor */
  63 OSObject::MetaClass::MetaClass()
  64     : OSMetaClass("OSObject", OSObject::superClass, sizeof(OSObject))
  65     { }
  66
  67 // Virtual Padding
  68 OSMetaClassDefineReservedUnused(OSObject,  0);
  69 OSMetaClassDefineReservedUnused(OSObject,  1);
  70 OSMetaClassDefineReservedUnused(OSObject,  2);
  71 OSMetaClassDefineReservedUnused(OSObject,  3);
  72 OSMetaClassDefineReservedUnused(OSObject,  4);
  73 OSMetaClassDefineReservedUnused(OSObject,  5);
  74 OSMetaClassDefineReservedUnused(OSObject,  6);
  75 OSMetaClassDefineReservedUnused(OSObject,  7);
  76 OSMetaClassDefineReservedUnused(OSObject,  8);
  77 OSMetaClassDefineReservedUnused(OSObject,  9);
  78 OSMetaClassDefineReservedUnused(OSObject, 10);
  79 OSMetaClassDefineReservedUnused(OSObject, 11);
  80 OSMetaClassDefineReservedUnused(OSObject, 12);
  81 OSMetaClassDefineReservedUnused(OSObject, 13);
  82 OSMetaClassDefineReservedUnused(OSObject, 14);
  83 OSMetaClassDefineReservedUnused(OSObject, 15);
  84 OSMetaClassDefineReservedUnused(OSObject, 16);
  85 OSMetaClassDefineReservedUnused(OSObject, 17);
  86 OSMetaClassDefineReservedUnused(OSObject, 18);
  87 OSMetaClassDefineReservedUnused(OSObject, 19);
  88 OSMetaClassDefineReservedUnused(OSObject, 20);
  89 OSMetaClassDefineReservedUnused(OSObject, 21);
  90 OSMetaClassDefineReservedUnused(OSObject, 22);
  91 OSMetaClassDefineReservedUnused(OSObject, 23);
  92 OSMetaClassDefineReservedUnused(OSObject, 24);
  93 OSMetaClassDefineReservedUnused(OSObject, 25);
  94 OSMetaClassDefineReservedUnused(OSObject, 26);
  95 OSMetaClassDefineReservedUnused(OSObject, 27);
  96 OSMetaClassDefineReservedUnused(OSObject, 28);
  97 OSMetaClassDefineReservedUnused(OSObject, 29);
  98 OSMetaClassDefineReservedUnused(OSObject, 30);
  99 OSMetaClassDefineReservedUnused(OSObject, 31);
 100
 101 static const char *getClassName(const OSObject *obj)
 102 {
 103     const OSMetaClass *meta = obj->getMetaClass();
 104     return (meta) ? meta->getClassName() : "unknown class?";
 105 }
 106
 107 bool OSObject::init()
 108     { return true; }
 109
 110 #if (!__ppc__) || (__GNUC__ < 3)
 111
 112 // Implemented in assembler in post gcc 3.x systems as we have a problem
 113 // where the destructor in gcc2.95 gets 2 arguments.  The second argument
 114 // appears to be a flag argument.  I have copied the assembler from Puma xnu
 115 // to OSRuntimeSupport.c  So for 2.95 builds use the C
 116 void OSObject::free()
 117 {
 118     const OSMetaClass *meta = getMetaClass();
 119
 120     if (meta)
 121         meta->instanceDestructed();
 122     delete this;
 123 }
 124 #endif /* (!__ppc__) || (__GNUC__ < 3) */
 125
 126 int OSObject::getRetainCount() const
 127 {
 128     return (int) ((UInt16) retainCount);
 129 }
 130
 131 void OSObject::taggedRetain(const void *tag) const
 132 {
 133     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 134     UInt32 inc = 1;
 135     UInt32 origCount;
 136     UInt32 newCount;
 137
 138     // Increment the collection bucket.
 139     if ((const void *) OSTypeID(OSCollection) == tag)
 140         inc |= (1UL<<16);
 141
 142     do {
 143         origCount = *countP;
 144         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 145             const char *msg;
 146             if (origCount & 0x1) {
 147                 // If count == 0xffff that means we are freeing now so we can
 148                 // just return obviously somebody is cleaning up dangling
 149                 // references.
 150                 msg = "Attempting to retain a freed object";
 151             }
 152             else {
 153                 // If count == 0xfffe then we have wrapped our reference count.
 154                 // We should stop counting now as this reference must be
 155                 // leaked rather than accidently wrapping around the clock and
 156                 // freeing a very active object later.
 157
 158 #if !DEBUG
 159                 break;  // Break out of update loop which pegs the reference
 160 #else DEBUG
 161                 // @@@ gvdl: eventually need to make this panic optional
 162                 // based on a boot argument i.e. debug= boot flag
 163                 msg = "About to wrap the reference count, reference leak?";
 164 #endif /* !DEBUG */
 165             }
 166             panic("OSObject::refcount: %s", msg);
 167         }
 168
 169         newCount = origCount + inc;
 170     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 171 }
 172
 173 void OSObject::taggedRelease(const void *tag) const
 174 {
 175     taggedRelease(tag, 1);
 176 }
 177
 178 void OSObject::taggedRelease(const void *tag, const int when) const
 179 {
 180     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 181     UInt32 dec = 1;
 182     UInt32 origCount;
 183     UInt32 newCount;
 184     UInt32 actualCount;
 185
 186     // Increment the collection bucket.
 187     if ((const void *) OSTypeID(OSCollection) == tag)
 188         dec |= (1UL<<16);
 189
 190     do {
 191         origCount = *countP;
 192
 193         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 194             if (origCount & 0x1) {
 195                 // If count == 0xffff that means we are freeing now so we can
 196                 // just return obviously somebody is cleaning up some dangling
 197                 // references.  So we blow out immediately.
 198                 return;
 199             }
 200             else {
 201                 // If count == 0xfffe then we have wrapped our reference
 202                 // count.  We should stop counting now as this reference must be
 203                 // leaked rather than accidently freeing an active object later.
 204
 205 #if !DEBUG
 206                 return; // return out of function which pegs the reference
 207 #else DEBUG
 208                 // @@@ gvdl: eventually need to make this panic optional
 209                 // based on a boot argument i.e. debug= boot flag
 210                 panic("OSObject::refcount: %s",
 211                       "About to unreference a pegged object, reference leak?");
 212 #endif /* !DEBUG */
 213             }
 214         }
 215         actualCount = origCount - dec;
 216         if ((UInt16) actualCount < when)
 217             newCount = 0xffff;
 218         else
 219             newCount = actualCount;
 220
 221     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 222
 223     //
 224     // This panic means that we have just attempted to release an object
 225     // who's retain count has gone to less than the number of collections
 226     // it is a member off.  Take a panic immediately.
 227     // In Fact the panic MAY not be a registry corruption but it is
 228     // ALWAYS the wrong thing to do.  I call it a registry corruption 'cause
 229     // the registry is the biggest single use of a network of collections.
 230     //
 231     if ((UInt16) actualCount < (actualCount >> 16))
 232         panic("A driver releasing a(n) %s has corrupted the registry\n",
 233             getClassName(this));
 234
 235     // Check for a 'free' condition and that if we are first through
 236     if (newCount == 0xffff)
 237         ((OSObject *) this)->free();
 238 }
 239
 240 void OSObject::release() const
 241 {
 242     taggedRelease(0);
 243 }
 244
 245 void OSObject::retain() const
 246 {
 247     taggedRetain(0);
 248 }
 249
 250 void OSObject::release(int when) const
 251 {
 252     taggedRelease(0, when);
 253 }
 254
 255 bool OSObject::serialize(OSSerialize *s) const
 256 {
 257     if (s->previouslySerialized(this)) return true;
 258
 259     if (!s->addXMLStartTag(this, "string")) return false;
 260
 261     if (!s->addString(getClassName(this))) return false;
 262     if (!s->addString(" is not serializable")) return false;
 263
 264     return s->addXMLEndTag("string");
 265 }
 266
 267 void *OSObject::operator new(size_t size)
 268 {
 269     void *mem = (void *) kalloc(size);
 270     assert(mem);
 271     bzero(mem, size);
 272
 273     ACCUMSIZE(size);
 274
 275     return mem;
 276 }
 277
 278 void OSObject::operator delete(void *mem, size_t size)
 279 {
 280     kfree((vm_offset_t) mem, size);
 281
 282     ACCUMSIZE(-size);
 283 }