src/cbdata.cc

   1
   2 /*
   3  * $Id: cbdata.cc,v 1.77 2008/02/26 21:49:34 amosjeffries Exp $
   4  *
   5  * DEBUG: section 45    Callback Data Registry
   6  * ORIGINAL AUTHOR: Duane Wessels
   7  * Modified by Moez Mahfoudh (08/12/2000)
   8  * History added by Robert Collins (2002-10-25)
   9  *
  10  * SQUID Web Proxy Cache          http://www.squid-cache.org/
  11  * ----------------------------------------------------------
  12  *
  13  *  Squid is the result of efforts by numerous individuals from
  14  *  the Internet community; see the CONTRIBUTORS file for full
  15  *  details.   Many organizations have provided support for Squid's
  16  *  development; see the SPONSORS file for full details.  Squid is
  17  *  Copyrighted (C) 2001 by the Regents of the University of
  18  *  California; see the COPYRIGHT file for full details.  Squid
  19  *  incorporates software developed and/or copyrighted by other
  20  *  sources; see the CREDITS file for full details.
  21  *
  22  *  This program is free software; you can redistribute it and/or modify
  23  *  it under the terms of the GNU General Public License as published by
  24  *  the Free Software Foundation; either version 2 of the License, or
  25  *  (at your option) any later version.
  26  *
  27  *  This program is distributed in the hope that it will be useful,
  28  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  *  GNU General Public License for more details.
  31  *
  32  *  You should have received a copy of the GNU General Public License
  33  *  along with this program; if not, write to the Free Software
  34  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  35  *
  36  */
  37
  38 /**
  39  \defgroup CBDATAInternal Callback Data Allocator Internals
  40  \ingroup CBDATAAPI
  41  *
  42  * These routines manage a set of registered callback data pointers.
  43  * One of the easiest ways to make Squid coredump is to issue a
  44  * callback to for some data structure which has previously been
  45  * freed.  With these routines, we register (add) callback data
  46  * pointers, lock them just before registering the callback function,
  47  * validate them before issuing the callback, and then free them
  48  * when finished.
  49  */
  50
  51 #include "cbdata.h"
  52 #include "CacheManager.h"
  53 #include "Store.h"
  54 #if CBDATA_DEBUG
  55 #include "Stack.h"
  56 #endif
  57 #include "Generic.h"
  58
  59 #if WITH_VALGRIND
  60 #define HASHED_CBDATA 1
  61 #endif
  62
  63 static int cbdataCount = 0;
  64 #if CBDATA_DEBUG
  65 dlink_list cbdataEntries;
  66 #endif
  67
  68 #if CBDATA_DEBUG
  69
  70 class CBDataCall
  71 {
  72
  73 public:
  74     CBDataCall (char const *callLabel, char const *aFile, int aLine) : label(callLabel), file(aFile), line(aLine){}
  75
  76     char const *label;
  77     char const *file;
  78     int line;
  79 };
  80
  81 #endif
  82
  83 /// \ingroup CBDATAInternal
  84 #define OFFSET_OF(TYPE, MEMBER) ((size_t) &(((TYPE) *)0)->(MEMBER))
  85
  86 /// \ingroup CBDATAInternal
  87 class cbdata
  88 {
  89     /** \todo examine making cbdata templated on this - so we get type
  90      * safe access to data - RBC 20030902 */
  91 public:
  92 #if HASHED_CBDATA
  93     hash_link hash;     // Must be first
  94 #endif
  95
  96 #if CBDATA_DEBUG
  97
  98     void dump(StoreEntry *)const;
  99 #endif
 100
 101 #if !HASHED_CBDATA
 102     void *operator new(size_t size, void *where);
 103     void operator delete(void *where, void *where2);
 104 #else
 105     MEMPROXY_CLASS(cndata);
 106 #endif
 107
 108     ~cbdata();
 109     int valid;
 110     int locks;
 111     cbdata_type type;
 112 #if CBDATA_DEBUG
 113
 114     void addHistory(char const *label, char const *file, int line)
 115     {
 116         if (calls.size() > 1000)
 117             return;
 118
 119         calls.push_back(new CBDataCall(label, file, line));
 120     }
 121
 122     dlink_node link;
 123     const char *file;
 124     int line;
 125     Stack<CBDataCall*> calls;
 126 #endif
 127
 128     /* cookie used while debugging */
 129     long cookie;
 130     void check(int line) const {assert(cookie == ((long)this ^ Cookie));}
 131     static const long Cookie;
 132
 133 #if !HASHED_CBDATA
 134     size_t dataSize() const { return sizeof(data);}
 135     static long MakeOffset();
 136     static const long Offset;
 137     /* MUST be the last per-instance member */
 138     void *data;
 139 #endif
 140
 141 };
 142
 143 const long cbdata::Cookie((long)0xDEADBEEF);
 144 #if !HASHED_CBDATA
 145 const long cbdata::Offset(MakeOffset());
 146
 147 void *
 148 cbdata::operator new(size_t size, void *where)
 149 {
 150     // assert (size == sizeof(cbdata));
 151     return where;
 152 }
 153
 154 /**
 155  * Only ever invoked when placement new throws
 156  * an exception. Used to prevent an incorrect
 157  * free.
 158  */
 159 void
 160 cbdata::operator delete(void *where, void *where2)
 161 {
 162     ; // empty.
 163 }
 164
 165 long
 166 cbdata::MakeOffset()
 167 {
 168     cbdata *zero = (cbdata *)0L;
 169     void **dataOffset = &zero->data;
 170     return (long)dataOffset;
 171 }
 172 #else
 173 MEMPROXY_CLASS_INLINE(cbdata);
 174 #endif
 175
 176 static OBJH cbdataDump;
 177 #ifdef CBDATA_DEBUG
 178 static OBJH cbdataDumpHistory;
 179 #endif
 180
 181 /// \ingroup CBDATAInternal
 182 struct CBDataIndex
 183 {
 184     MemAllocator *pool;
 185     FREE *free_func;
 186 }
 187 *cbdata_index = NULL;
 188
 189 /// \ingroup CBDATAInternal
 190 int cbdata_types = 0;
 191
 192 #if HASHED_CBDATA
 193 static hash_table *cbdata_htable = NULL;
 194
 195 static int
 196 cbdata_cmp(const void *p1, const void *p2)
 197 {
 198     return (char *) p1 - (char *) p2;
 199 }
 200
 201 static unsigned int
 202 cbdata_hash(const void *p, unsigned int mod)
 203 {
 204     return ((unsigned long) p >> 8) % mod;
 205 }
 206 #endif
 207
 208
 209 cbdata::~cbdata()
 210 {
 211 #if CBDATA_DEBUG
 212     CBDataCall *aCall;
 213
 214     while ((aCall = calls.pop()))
 215         delete aCall;
 216
 217 #endif
 218
 219     FREE *free_func = cbdata_index[type].free_func;
 220
 221 #if HASHED_CBDATA
 222     void *p = hash.key;
 223 #else
 224     void *p = &data;
 225 #endif
 226
 227     if (free_func)
 228         free_func(p);
 229 }
 230
 231 static void
 232 cbdataInternalInitType(cbdata_type type, const char *name, int size, FREE * free_func)
 233 {
 234     char *label;
 235     assert (type == cbdata_types + 1);
 236
 237     cbdata_index = (CBDataIndex *)xrealloc(cbdata_index, (type + 1) * sizeof(*cbdata_index));
 238     memset(&cbdata_index[type], 0, sizeof(*cbdata_index));
 239     cbdata_types = type;
 240
 241     label = (char *)xmalloc(strlen(name) + 20);
 242
 243     snprintf(label, strlen(name) + 20, "cbdata %s (%d)", name, (int) type);
 244
 245 #if !HASHED_CBDATA
 246     assert((size_t)cbdata::Offset == (sizeof(cbdata) - ((cbdata *)NULL)->dataSize()));
 247     size += cbdata::Offset;
 248 #endif
 249
 250     cbdata_index[type].pool = memPoolCreate(label, size);
 251
 252     cbdata_index[type].free_func = free_func;
 253
 254 #if HASHED_CBDATA
 255     if (!cbdata_htable)
 256         cbdata_htable = hash_create(cbdata_cmp, 1 << 12, cbdata_hash);
 257 #endif
 258 }
 259
 260 cbdata_type
 261 cbdataInternalAddType(cbdata_type type, const char *name, int size, FREE * free_func)
 262 {
 263     if (type)
 264         return type;
 265
 266     type = (cbdata_type)(cbdata_types + 1);
 267
 268     cbdataInternalInitType(type, name, size, free_func);
 269
 270     return type;
 271 }
 272
 273 void
 274 cbdataRegisterWithCacheManager(CacheManager & manager)
 275 {
 276     manager.registerAction("cbdata",
 277                            "Callback Data Registry Contents",
 278                            cbdataDump, 0, 1);
 279 #if CBDATA_DEBUG
 280
 281     manager.registerAction("cbdatahistory",
 282                            "Detailed call history for all current cbdata contents",
 283                            cbdataDumpHistory, 0, 1);
 284 #endif
 285 }
 286
 287 void *
 288 #if CBDATA_DEBUG
 289 cbdataInternalAllocDbg(cbdata_type type, const char *file, int line)
 290 #else
 291 cbdataInternalAlloc(cbdata_type type)
 292 #endif
 293 {
 294     cbdata *c;
 295     void *p;
 296     assert(type > 0 && type <= cbdata_types);
 297     /* placement new: the pool alloc gives us cbdata + user type memory space
 298      * and we init it with cbdata at the start of it
 299      */
 300 #if HASHED_CBDATA
 301     c = new cbdata;
 302     p = cbdata_index[type].pool->alloc();
 303     c->hash.key = p;
 304     hash_join(cbdata_htable, &c->hash);
 305 #else
 306     c = new (cbdata_index[type].pool->alloc()) cbdata;
 307     p = (void *)&c->data;
 308 #endif
 309
 310     c->type = type;
 311     c->valid = 1;
 312     c->locks = 0;
 313     c->cookie = (long) c ^ cbdata::Cookie;
 314     cbdataCount++;
 315 #if CBDATA_DEBUG
 316
 317     c->file = file;
 318     c->line = line;
 319     c->calls = Stack<CBDataCall *> ();
 320     c->addHistory("Alloc", file, line);
 321     dlinkAdd(c, &c->link, &cbdataEntries);
 322     debugs(45, 3, "cbdataAlloc: " << p << " " << file << ":" << line);
 323 #endif
 324
 325     return p;
 326 }
 327
 328 void *
 329 #if CBDATA_DEBUG
 330 cbdataInternalFreeDbg(void *p, const char *file, int line)
 331 #else
 332 cbdataInternalFree(void *p)
 333 #endif
 334 {
 335     cbdata *c;
 336 #if HASHED_CBDATA
 337     c = (cbdata *) hash_lookup(cbdata_htable, p);
 338 #else
 339     c = (cbdata *) (((char *) p) - cbdata::Offset);
 340 #endif
 341 #if CBDATA_DEBUG
 342
 343     debugs(45, 3, "cbdataFree: " << p << " " << file << ":" << line);
 344 #else
 345
 346     debugs(45, 9, "cbdataFree: " << p);
 347 #endif
 348
 349     c->check(__LINE__);
 350     assert(c->valid);
 351     c->valid = 0;
 352 #if CBDATA_DEBUG
 353
 354     c->addHistory("Free", file, line);
 355 #endif
 356
 357     if (c->locks) {
 358         debugs(45, 9, "cbdataFree: " << p << " has " << c->locks << " locks, not freeing");
 359         return NULL;
 360     }
 361
 362     cbdataCount--;
 363     debugs(45, 9, "cbdataFree: Freeing " << p);
 364 #if CBDATA_DEBUG
 365
 366     dlinkDelete(&c->link, &cbdataEntries);
 367 #endif
 368
 369     /* This is ugly. But: operator delete doesn't get
 370      * the type parameter, so we can't use that
 371      * to free the memory.
 372      * So, we free it ourselves.
 373      * Note that this means a non-placement
 374      * new would be a seriously bad idea.
 375      * Lastly, if we where a templated class,
 376      * we could use the normal delete operator
 377      * and it would Just Work. RBC 20030902
 378      */
 379     cbdata_type theType = c->type;
 380 #if HASHED_CBDATA
 381     hash_remove_link(cbdata_htable, &c->hash);
 382     delete c;
 383     cbdata_index[theType].pool->free((void *)p);
 384 #else
 385     c->cbdata::~cbdata();
 386     cbdata_index[theType].pool->free(c);
 387 #endif
 388     return NULL;
 389 }
 390
 391 void
 392 #if CBDATA_DEBUG
 393 cbdataInternalLockDbg(const void *p, const char *file, int line)
 394 #else
 395 cbdataInternalLock(const void *p)
 396 #endif
 397 {
 398     cbdata *c;
 399
 400     if (p == NULL)
 401         return;
 402
 403 #if HASHED_CBDATA
 404     c = (cbdata *) hash_lookup(cbdata_htable, p);
 405 #else
 406     c = (cbdata *) (((char *) p) - cbdata::Offset);
 407 #endif
 408
 409 #if CBDATA_DEBUG
 410
 411     debugs(45, 3, "cbdataLock: " << p << "=" << (c ? c->locks + 1 : -1) << " " << file << ":" << line);
 412
 413     c->addHistory("Reference", file, line);
 414
 415 #else
 416
 417     debugs(45, 9, "cbdataLock: " << p << "=" << (c ? c->locks + 1 : -1));
 418
 419 #endif
 420
 421     c->check(__LINE__);
 422
 423     assert(c->locks < 65535);
 424
 425     c->locks++;
 426 }
 427
 428 void
 429 #if CBDATA_DEBUG
 430 cbdataInternalUnlockDbg(const void *p, const char *file, int line)
 431 #else
 432 cbdataInternalUnlock(const void *p)
 433 #endif
 434 {
 435     cbdata *c;
 436
 437     if (p == NULL)
 438         return;
 439
 440 #if HASHED_CBDATA
 441     c = (cbdata *) hash_lookup(cbdata_htable, p);
 442 #else
 443     c = (cbdata *) (((char *) p) - cbdata::Offset);
 444 #endif
 445
 446 #if CBDATA_DEBUG
 447
 448     debugs(45, 3, "cbdataUnlock: " << p << "=" << (c ? c->locks - 1 : -1) << " " << file << ":" << line);
 449
 450     c->addHistory("Dereference", file, line);
 451
 452 #else
 453
 454     debugs(45, 9, "cbdataUnlock: " << p << "=" << (c ? c->locks - 1 : -1));
 455
 456 #endif
 457
 458     c->check(__LINE__);
 459
 460     assert(c != NULL);
 461
 462     assert(c->locks > 0);
 463
 464     c->locks--;
 465
 466     if (c->valid || c->locks)
 467         return;
 468
 469     cbdataCount--;
 470
 471     debugs(45, 9, "cbdataUnlock: Freeing " << p);
 472
 473 #if CBDATA_DEBUG
 474
 475     dlinkDelete(&c->link, &cbdataEntries);
 476
 477 #endif
 478
 479     /* This is ugly. But: operator delete doesn't get
 480      * the type parameter, so we can't use that
 481      * to free the memory.
 482      * So, we free it ourselves.
 483      * Note that this means a non-placement
 484      * new would be a seriously bad idea.
 485      * Lastly, if we where a templated class,
 486      * we could use the normal delete operator
 487      * and it would Just Work. RBC 20030902
 488      */
 489     cbdata_type theType = c->type;
 490 #if HASHED_CBDATA
 491     hash_remove_link(cbdata_htable, &c->hash);
 492     delete c;
 493     cbdata_index[theType].pool->free((void *)p);
 494 #else
 495     c->cbdata::~cbdata();
 496     cbdata_index[theType].pool->free(c);
 497 #endif
 498 }
 499
 500 int
 501 cbdataReferenceValid(const void *p)
 502 {
 503     cbdata *c;
 504
 505     if (p == NULL)
 506         return 1;               /* A NULL pointer cannot become invalid */
 507
 508     debugs(45, 9, "cbdataReferenceValid: " << p);
 509
 510 #if HASHED_CBDATA
 511     c = (cbdata *) hash_lookup(cbdata_htable, p);
 512 #else
 513     c = (cbdata *) (((char *) p) - cbdata::Offset);
 514 #endif
 515
 516     c->check(__LINE__);
 517
 518     assert(c->locks > 0);
 519
 520     return c->valid;
 521 }
 522
 523 int
 524 #if CBDATA_DEBUG
 525 cbdataInternalReferenceDoneValidDbg(void **pp, void **tp, const char *file, int line)
 526 #else
 527 cbdataInternalReferenceDoneValid(void **pp, void **tp)
 528 #endif
 529 {
 530     void *p = (void *) *pp;
 531     int valid = cbdataReferenceValid(p);
 532     *pp = NULL;
 533 #if CBDATA_DEBUG
 534
 535     cbdataInternalUnlockDbg(p, file, line);
 536 #else
 537
 538     cbdataInternalUnlock(p);
 539 #endif
 540
 541     if (valid) {
 542         *tp = p;
 543         return 1;
 544     } else {
 545         *tp = NULL;
 546         return 0;
 547     }
 548 }
 549
 550 #if CBDATA_DEBUG
 551 void
 552 cbdata::dump(StoreEntry *sentry) const
 553 {
 554 #if HASHED_CBDATA
 555     void *p = (void *)hash.key;
 556 #else
 557     void *p = (void *)&data;
 558 #endif
 559     storeAppendPrintf(sentry, "%c%p\t%d\t%d\t%20s:%-5d\n", valid ? ' ' :
 560                       '!', p, type, locks, file, line);
 561 }
 562
 563 struct CBDataDumper : public unary_function<cbdata, void>
 564 {
 565     CBDataDumper(StoreEntry *anEntry):where(anEntry){}
 566
 567     void operator()(cbdata const &x)
 568     {
 569         x.dump(where);
 570     }
 571
 572     StoreEntry *where;
 573 };
 574
 575 #endif
 576
 577 static void
 578 cbdataDump(StoreEntry * sentry)
 579 {
 580     storeAppendPrintf(sentry, "%d cbdata entries\n", cbdataCount);
 581 #if CBDATA_DEBUG
 582
 583     storeAppendPrintf(sentry, "Pointer\tType\tLocks\tAllocated by\n");
 584     CBDataDumper dumper(sentry);
 585     for_each (cbdataEntries, dumper);
 586     storeAppendPrintf(sentry, "\n");
 587     storeAppendPrintf(sentry, "types\tsize\tallocated\ttotal\n");
 588
 589     for (int i = 1; i < cbdata_types; i++) {
 590         MemAllocator *pool = cbdata_index[i].pool;
 591
 592         if (pool) {
 593 #if HASHED_CBDATA
 594             int obj_size = pool->objectSize();
 595 #else
 596             int obj_size = pool->objectSize() - cbdata::Offset;
 597 #endif
 598             storeAppendPrintf(sentry, "%s\t%d\t%ld\t%ld\n", pool->objectType() + 7, obj_size, (long int)pool->getMeter().inuse.level, (long int)obj_size * pool->getMeter().inuse.level);
 599         }
 600     }
 601
 602 #else
 603     storeAppendPrintf(sentry, "detailed allocation information only available when compiled with CBDATA_DEBUG\n");
 604
 605 #endif
 606
 607     storeAppendPrintf(sentry, "\nsee also \"Memory utilization\" for detailed per type statistics\n");
 608 }
 609
 610 CBDATA_CLASS_INIT(generic_cbdata);
 611
 612 #if CBDATA_DEBUG
 613
 614 struct CBDataCallDumper : public unary_function<CBDataCall, void>
 615 {
 616     CBDataCallDumper (StoreEntry *anEntry):where(anEntry){}
 617
 618     void operator()(CBDataCall const &x)
 619     {
 620         storeAppendPrintf(where, "%s\t%s\t%d\n", x.label, x.file, x.line);
 621     }
 622
 623     StoreEntry *where;
 624 };
 625
 626 struct CBDataHistoryDumper : public CBDataDumper
 627 {
 628     CBDataHistoryDumper(StoreEntry *anEntry):CBDataDumper(anEntry),where(anEntry), callDumper(anEntry){}
 629
 630     void operator()(cbdata const &x)
 631     {
 632         CBDataDumper::operator()(x);
 633         storeAppendPrintf(where, "\n");
 634         storeAppendPrintf(where, "Action\tFile\tLine\n");
 635         for_each (x.calls,callDumper);
 636         storeAppendPrintf(where, "\n");
 637     }
 638
 639     StoreEntry *where;
 640     CBDataCallDumper callDumper;
 641 };
 642
 643 void
 644 cbdataDumpHistory(StoreEntry *sentry)
 645 {
 646     storeAppendPrintf(sentry, "%d cbdata entries\n", cbdataCount);
 647     storeAppendPrintf(sentry, "Pointer\tType\tLocks\tAllocated by\n");
 648     CBDataHistoryDumper dumper(sentry);
 649     for_each (cbdataEntries, dumper);
 650 }
 651
 652 #endif