libkern/c++/OSObject.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /* OSObject.cpp created by gvdl on Fri 1998-11-17 */
  31
  32 #include <libkern/c++/OSObject.h>
  33 #include <libkern/c++/OSSerialize.h>
  34 #include <libkern/c++/OSLib.h>
  35 #include <libkern/c++/OSCPPDebug.h>
  36 #include <libkern/OSAtomic.h>
  37
  38 #include <libkern/c++/OSCollection.h>
  39
  40 __BEGIN_DECLS
  41 int debug_ivars_size;
  42 __END_DECLS
  43
  44 #if OSALLOCDEBUG
  45 #define ACCUMSIZE(s) do { debug_ivars_size += (s); } while(0)
  46 #else
  47 #define ACCUMSIZE(s)
  48 #endif
  49
  50 // OSDefineMetaClassAndAbstractStructors(OSObject, 0);
  51 /* Class global data */
  52 OSObject::MetaClass OSObject::gMetaClass;
  53 const OSMetaClass * const OSObject::metaClass = &OSObject::gMetaClass;
  54 const OSMetaClass * const OSObject::superClass = 0;
  55
  56 /* Class member functions - Can't use defaults */
  57 OSObject::OSObject()                    { retainCount = 1; }
  58 OSObject::OSObject(const OSMetaClass *) { retainCount = 1; }
  59 OSObject::~OSObject()                   { }
  60 const OSMetaClass * OSObject::getMetaClass() const
  61     { return &gMetaClass; }
  62 OSObject *OSObject::MetaClass::alloc() const { return 0; }
  63
  64 /* The OSObject::MetaClass constructor */
  65 OSObject::MetaClass::MetaClass()
  66     : OSMetaClass("OSObject", OSObject::superClass, sizeof(OSObject))
  67     { }
  68
  69 // Virtual Padding
  70 OSMetaClassDefineReservedUnused(OSObject,  0);
  71 OSMetaClassDefineReservedUnused(OSObject,  1);
  72 OSMetaClassDefineReservedUnused(OSObject,  2);
  73 OSMetaClassDefineReservedUnused(OSObject,  3);
  74 OSMetaClassDefineReservedUnused(OSObject,  4);
  75 OSMetaClassDefineReservedUnused(OSObject,  5);
  76 OSMetaClassDefineReservedUnused(OSObject,  6);
  77 OSMetaClassDefineReservedUnused(OSObject,  7);
  78 OSMetaClassDefineReservedUnused(OSObject,  8);
  79 OSMetaClassDefineReservedUnused(OSObject,  9);
  80 OSMetaClassDefineReservedUnused(OSObject, 10);
  81 OSMetaClassDefineReservedUnused(OSObject, 11);
  82 OSMetaClassDefineReservedUnused(OSObject, 12);
  83 OSMetaClassDefineReservedUnused(OSObject, 13);
  84 OSMetaClassDefineReservedUnused(OSObject, 14);
  85 OSMetaClassDefineReservedUnused(OSObject, 15);
  86 OSMetaClassDefineReservedUnused(OSObject, 16);
  87 OSMetaClassDefineReservedUnused(OSObject, 17);
  88 OSMetaClassDefineReservedUnused(OSObject, 18);
  89 OSMetaClassDefineReservedUnused(OSObject, 19);
  90 OSMetaClassDefineReservedUnused(OSObject, 20);
  91 OSMetaClassDefineReservedUnused(OSObject, 21);
  92 OSMetaClassDefineReservedUnused(OSObject, 22);
  93 OSMetaClassDefineReservedUnused(OSObject, 23);
  94 OSMetaClassDefineReservedUnused(OSObject, 24);
  95 OSMetaClassDefineReservedUnused(OSObject, 25);
  96 OSMetaClassDefineReservedUnused(OSObject, 26);
  97 OSMetaClassDefineReservedUnused(OSObject, 27);
  98 OSMetaClassDefineReservedUnused(OSObject, 28);
  99 OSMetaClassDefineReservedUnused(OSObject, 29);
 100 OSMetaClassDefineReservedUnused(OSObject, 30);
 101 OSMetaClassDefineReservedUnused(OSObject, 31);
 102
 103 static const char *getClassName(const OSObject *obj)
 104 {
 105     const OSMetaClass *meta = obj->getMetaClass();
 106     return (meta) ? meta->getClassName() : "unknown class?";
 107 }
 108
 109 bool OSObject::init()
 110     { return true; }
 111
 112 #if (!__ppc__) || (__GNUC__ < 3)
 113
 114 // Implemented in assembler in post gcc 3.x systems as we have a problem
 115 // where the destructor in gcc2.95 gets 2 arguments.  The second argument
 116 // appears to be a flag argument.  I have copied the assembler from Puma xnu
 117 // to OSRuntimeSupport.c  So for 2.95 builds use the C
 118 void OSObject::free()
 119 {
 120     const OSMetaClass *meta = getMetaClass();
 121
 122     if (meta)
 123         meta->instanceDestructed();
 124     delete this;
 125 }
 126 #endif /* (!__ppc__) || (__GNUC__ < 3) */
 127
 128 int OSObject::getRetainCount() const
 129 {
 130     return (int) ((UInt16) retainCount);
 131 }
 132
 133 void OSObject::taggedRetain(const void *tag) const
 134 {
 135     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 136     UInt32 inc = 1;
 137     UInt32 origCount;
 138     UInt32 newCount;
 139
 140     // Increment the collection bucket.
 141     if ((const void *) OSTypeID(OSCollection) == tag)
 142         inc |= (1UL<<16);
 143
 144     do {
 145         origCount = *countP;
 146         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 147             const char *msg;
 148             if (origCount & 0x1) {
 149                 // If count == 0xffff that means we are freeing now so we can
 150                 // just return obviously somebody is cleaning up dangling
 151                 // references.
 152                 msg = "Attempting to retain a freed object";
 153             }
 154             else {
 155                 // If count == 0xfffe then we have wrapped our reference count.
 156                 // We should stop counting now as this reference must be
 157                 // leaked rather than accidently wrapping around the clock and
 158                 // freeing a very active object later.
 159
 160 #if !DEBUG
 161                 break;  // Break out of update loop which pegs the reference
 162 #else DEBUG
 163                 // @@@ gvdl: eventually need to make this panic optional
 164                 // based on a boot argument i.e. debug= boot flag
 165                 msg = "About to wrap the reference count, reference leak?";
 166 #endif /* !DEBUG */
 167             }
 168             panic("OSObject::refcount: %s", msg);
 169         }
 170
 171         newCount = origCount + inc;
 172     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 173 }
 174
 175 void OSObject::taggedRelease(const void *tag) const
 176 {
 177     taggedRelease(tag, 1);
 178 }
 179
 180 void OSObject::taggedRelease(const void *tag, const int when) const
 181 {
 182     volatile UInt32 *countP = (volatile UInt32 *) &retainCount;
 183     UInt32 dec = 1;
 184     UInt32 origCount;
 185     UInt32 newCount;
 186     UInt32 actualCount;
 187
 188     // Increment the collection bucket.
 189     if ((const void *) OSTypeID(OSCollection) == tag)
 190         dec |= (1UL<<16);
 191
 192     do {
 193         origCount = *countP;
 194
 195         if ( ((UInt16) origCount | 0x1) == 0xffff ) {
 196             if (origCount & 0x1) {
 197                 // If count == 0xffff that means we are freeing now so we can
 198                 // just return obviously somebody is cleaning up some dangling
 199                 // references.  So we blow out immediately.
 200                 return;
 201             }
 202             else {
 203                 // If count == 0xfffe then we have wrapped our reference
 204                 // count.  We should stop counting now as this reference must be
 205                 // leaked rather than accidently freeing an active object later.
 206
 207 #if !DEBUG
 208                 return; // return out of function which pegs the reference
 209 #else DEBUG
 210                 // @@@ gvdl: eventually need to make this panic optional
 211                 // based on a boot argument i.e. debug= boot flag
 212                 panic("OSObject::refcount: %s",
 213                       "About to unreference a pegged object, reference leak?");
 214 #endif /* !DEBUG */
 215             }
 216         }
 217         actualCount = origCount - dec;
 218         if ((UInt16) actualCount < when)
 219             newCount = 0xffff;
 220         else
 221             newCount = actualCount;
 222
 223     } while (!OSCompareAndSwap(origCount, newCount, (UInt32 *) countP));
 224
 225     //
 226     // This panic means that we have just attempted to release an object
 227     // who's retain count has gone to less than the number of collections
 228     // it is a member off.  Take a panic immediately.
 229     // In Fact the panic MAY not be a registry corruption but it is
 230     // ALWAYS the wrong thing to do.  I call it a registry corruption 'cause
 231     // the registry is the biggest single use of a network of collections.
 232     //
 233     if ((UInt16) actualCount < (actualCount >> 16))
 234         panic("A driver releasing a(n) %s has corrupted the registry\n",
 235             getClassName(this));
 236
 237     // Check for a 'free' condition and that if we are first through
 238     if (newCount == 0xffff)
 239         ((OSObject *) this)->free();
 240 }
 241
 242 void OSObject::release() const
 243 {
 244     taggedRelease(0);
 245 }
 246
 247 void OSObject::retain() const
 248 {
 249     taggedRetain(0);
 250 }
 251
 252 void OSObject::release(int when) const
 253 {
 254     taggedRelease(0, when);
 255 }
 256
 257 bool OSObject::serialize(OSSerialize *s) const
 258 {
 259     if (s->previouslySerialized(this)) return true;
 260
 261     if (!s->addXMLStartTag(this, "string")) return false;
 262
 263     if (!s->addString(getClassName(this))) return false;
 264     if (!s->addString(" is not serializable")) return false;
 265
 266     return s->addXMLEndTag("string");
 267 }
 268
 269 void *OSObject::operator new(size_t size)
 270 {
 271     void *mem = (void *) kalloc(size);
 272     assert(mem);
 273     bzero(mem, size);
 274
 275     ACCUMSIZE(size);
 276
 277     return mem;
 278 }
 279
 280 void OSObject::operator delete(void *mem, size_t size)
 281 {
 282     kfree((vm_offset_t) mem, size);
 283
 284     ACCUMSIZE(-size);
 285 }