src/store_client.cc

   1 /*
   2  * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 90    Storage Manager Client-Side Interface */
  10
  11 #include "squid.h"
  12 #include "acl/FilledChecklist.h"
  13 #include "event.h"
  14 #include "globals.h"
  15 #include "HttpReply.h"
  16 #include "HttpRequest.h"
  17 #include "MemBuf.h"
  18 #include "MemObject.h"
  19 #include "mime_header.h"
  20 #include "profiler/Profiler.h"
  21 #include "SquidConfig.h"
  22 #include "StatCounters.h"
  23 #include "Store.h"
  24 #include "store_swapin.h"
  25 #include "StoreClient.h"
  26 #include "StoreMeta.h"
  27 #include "StoreMetaUnpacker.h"
  28 #if USE_DELAY_POOLS
  29 #include "DelayPools.h"
  30 #endif
  31
  32 /*
  33  * NOTE: 'Header' refers to the swapfile metadata header.
  34  *   'OBJHeader' refers to the object header, with cannonical
  35  *   processed object headers (which may derive from FTP/HTTP etc
  36  *   upstream protocols
  37  *       'Body' refers to the swapfile body, which is the full
  38  *        HTTP reply (including HTTP headers and body).
  39  */
  40 static StoreIOState::STRCB storeClientReadBody;
  41 static StoreIOState::STRCB storeClientReadHeader;
  42 static void storeClientCopy2(StoreEntry * e, store_client * sc);
  43 static EVH storeClientCopyEvent;
  44 static bool CheckQuickAbortIsReasonable(StoreEntry * entry);
  45
  46 CBDATA_CLASS_INIT(store_client);
  47
  48 /* StoreClient */
  49
  50 bool
  51 StoreClient::onCollapsingPath() const
  52 {
  53     if (!Config.onoff.collapsed_forwarding)
  54         return false;
  55
  56     if (!Config.accessList.collapsedForwardingAccess)
  57         return true;
  58
  59     ACLFilledChecklist checklist(Config.accessList.collapsedForwardingAccess, nullptr, nullptr);
  60     fillChecklist(checklist);
  61     return checklist.fastCheck().allowed();
  62 }
  63
  64 bool
  65 StoreClient::startCollapsingOn(const StoreEntry &e, const bool doingRevalidation)
  66 {
  67     if (!e.hittingRequiresCollapsing())
  68         return false; // collapsing is impossible due to the entry state
  69
  70     if (!onCollapsingPath())
  71         return false; // collapsing is impossible due to Squid configuration
  72
  73     /* collapsing is possible; the caller must collapse */
  74
  75     if (const auto tags = loggingTags()) {
  76         if (doingRevalidation)
  77             tags->collapsingHistory.revalidationCollapses++;
  78         else
  79             tags->collapsingHistory.otherCollapses++;
  80     }
  81
  82     debugs(85, 5, e << " doingRevalidation=" << doingRevalidation);
  83     return true;
  84 }
  85
  86 void
  87 StoreClient::fillChecklist(ACLFilledChecklist &checklist) const
  88 {
  89     // TODO: Consider moving all CF-related methods into a new dedicated class.
  90     Must(!"startCollapsingOn() caller must override fillChecklist()");
  91 }
  92
  93 /* store_client */
  94
  95 bool
  96 store_client::memReaderHasLowerOffset(int64_t anOffset) const
  97 {
  98     return getType() == STORE_MEM_CLIENT && copyInto.offset < anOffset;
  99 }
 100
 101 int
 102 store_client::getType() const
 103 {
 104     return type;
 105 }
 106
 107 #if STORE_CLIENT_LIST_DEBUG
 108 static store_client *
 109 storeClientListSearch(const MemObject * mem, void *data)
 110 {
 111     dlink_node *node;
 112     store_client *sc = NULL;
 113
 114     for (node = mem->clients.head; node; node = node->next) {
 115         sc = node->data;
 116
 117         if (sc->owner == data)
 118             return sc;
 119     }
 120
 121     return NULL;
 122 }
 123
 124 int
 125 storeClientIsThisAClient(store_client * sc, void *someClient)
 126 {
 127     return sc->owner == someClient;
 128 }
 129
 130 #endif
 131 #include "HttpRequest.h"
 132
 133 /* add client with fd to client list */
 134 store_client *
 135 storeClientListAdd(StoreEntry * e, void *data)
 136 {
 137     MemObject *mem = e->mem_obj;
 138     store_client *sc;
 139     assert(mem);
 140 #if STORE_CLIENT_LIST_DEBUG
 141
 142     if (storeClientListSearch(mem, data) != NULL)
 143         /* XXX die! */
 144         assert(1 == 0);
 145
 146 #endif
 147
 148     sc = new store_client (e);
 149
 150     mem->addClient(sc);
 151
 152     return sc;
 153 }
 154
 155 void
 156 store_client::callback(ssize_t sz, bool error)
 157 {
 158     size_t bSz = 0;
 159
 160     if (sz >= 0 && !error)
 161         bSz = sz;
 162
 163     StoreIOBuffer result(bSz, 0,copyInto.data);
 164
 165     if (sz < 0 || error)
 166         result.flags.error = 1;
 167
 168     result.offset = cmp_offset;
 169     assert(_callback.pending());
 170     cmp_offset = copyInto.offset + bSz;
 171     STCB *temphandler = _callback.callback_handler;
 172     void *cbdata = _callback.callback_data;
 173     _callback = Callback(NULL, NULL);
 174     copyInto.data = NULL;
 175
 176     if (cbdataReferenceValid(cbdata))
 177         temphandler(cbdata, result);
 178
 179     cbdataReferenceDone(cbdata);
 180 }
 181
 182 static void
 183 storeClientCopyEvent(void *data)
 184 {
 185     store_client *sc = (store_client *)data;
 186     debugs(90, 3, "storeClientCopyEvent: Running");
 187     assert (sc->flags.copy_event_pending);
 188     sc->flags.copy_event_pending = false;
 189
 190     if (!sc->_callback.pending())
 191         return;
 192
 193     storeClientCopy2(sc->entry, sc);
 194 }
 195
 196 store_client::store_client(StoreEntry *e) :
 197     cmp_offset(0),
 198 #if STORE_CLIENT_LIST_DEBUG
 199     owner(cbdataReference(data)),
 200 #endif
 201     entry(e),
 202     type(e->storeClientType()),
 203     object_ok(true)
 204 {
 205     flags.disk_io_pending = false;
 206     flags.store_copying = false;
 207     flags.copy_event_pending = false;
 208     ++ entry->refcount;
 209
 210     if (getType() == STORE_DISK_CLIENT) {
 211         /* assert we'll be able to get the data we want */
 212         /* maybe we should open swapin_sio here */
 213         assert(entry->hasDisk() && !entry->swapoutFailed());
 214     }
 215 }
 216
 217 store_client::~store_client()
 218 {}
 219
 220 /* copy bytes requested by the client */
 221 void
 222 storeClientCopy(store_client * sc,
 223                 StoreEntry * e,
 224                 StoreIOBuffer copyInto,
 225                 STCB * callback,
 226                 void *data)
 227 {
 228     assert (sc != NULL);
 229     sc->copy(e, copyInto,callback,data);
 230 }
 231
 232 void
 233 store_client::copy(StoreEntry * anEntry,
 234                    StoreIOBuffer copyRequest,
 235                    STCB * callback_fn,
 236                    void *data)
 237 {
 238     assert (anEntry == entry);
 239     assert (callback_fn);
 240     assert (data);
 241     assert(!EBIT_TEST(entry->flags, ENTRY_ABORTED));
 242     debugs(90, 3, "store_client::copy: " << entry->getMD5Text() << ", from " <<
 243            copyRequest.offset << ", for length " <<
 244            (int) copyRequest.length << ", cb " << callback_fn << ", cbdata " <<
 245            data);
 246
 247 #if STORE_CLIENT_LIST_DEBUG
 248
 249     assert(this == storeClientListSearch(entry->mem_obj, data));
 250 #endif
 251
 252     assert(!_callback.pending());
 253 #if ONLYCONTIGUOUSREQUESTS
 254
 255     assert(cmp_offset == copyRequest.offset);
 256 #endif
 257     /* range requests will skip into the body */
 258     cmp_offset = copyRequest.offset;
 259     _callback = Callback (callback_fn, cbdataReference(data));
 260     copyInto.data = copyRequest.data;
 261     copyInto.length = copyRequest.length;
 262     copyInto.offset = copyRequest.offset;
 263
 264     static bool copying (false);
 265     assert (!copying);
 266     copying = true;
 267     PROF_start(storeClient_kickReads);
 268     /* we might be blocking comm reads due to readahead limits
 269      * now we have a new offset, trigger those reads...
 270      */
 271     entry->mem_obj->kickReads();
 272     PROF_stop(storeClient_kickReads);
 273     copying = false;
 274
 275     anEntry->lock("store_client::copy"); // see deletion note below
 276
 277     storeClientCopy2(entry, this);
 278
 279     // Bug 3480: This store_client object may be deleted now if, for example,
 280     // the client rejects the hit response copied above. Use on-stack pointers!
 281
 282 #if USE_ADAPTATION
 283     anEntry->kickProducer();
 284 #endif
 285     anEntry->unlock("store_client::copy");
 286
 287     // Add no code here. This object may no longer exist.
 288 }
 289
 290 /// Whether there is (or will be) more entry data for us.
 291 bool
 292 store_client::moreToSend() const
 293 {
 294     if (entry->store_status == STORE_PENDING)
 295         return true; // there may be more coming
 296
 297     /* STORE_OK, including aborted entries: no more data is coming */
 298
 299     const int64_t len = entry->objectLen();
 300
 301     // If we do not know the entry length, then we have to open the swap file.
 302     const bool canSwapIn = entry->hasDisk();
 303     if (len < 0)
 304         return canSwapIn;
 305
 306     if (copyInto.offset >= len)
 307         return false; // sent everything there is
 308
 309     if (canSwapIn)
 310         return true; // if we lack prefix, we can swap it in
 311
 312     // If we cannot swap in, make sure we have what we want in RAM. Otherwise,
 313     // scheduleRead calls scheduleDiskRead which asserts without a swap file.
 314     const MemObject *mem = entry->mem_obj;
 315     return mem &&
 316            mem->inmem_lo <= copyInto.offset && copyInto.offset < mem->endOffset();
 317 }
 318
 319 static void
 320 storeClientCopy2(StoreEntry * e, store_client * sc)
 321 {
 322     /* reentrancy not allowed  - note this could lead to
 323      * dropped events
 324      */
 325
 326     if (sc->flags.copy_event_pending) {
 327         return;
 328     }
 329
 330     if (sc->flags.store_copying) {
 331         sc->flags.copy_event_pending = true;
 332         debugs(90, 3, "storeClientCopy2: Queueing storeClientCopyEvent()");
 333         eventAdd("storeClientCopyEvent", storeClientCopyEvent, sc, 0.0, 0);
 334         return;
 335     }
 336
 337     debugs(90, 3, "storeClientCopy2: " << e->getMD5Text());
 338     assert(sc->_callback.pending());
 339     /*
 340      * We used to check for ENTRY_ABORTED here.  But there were some
 341      * problems.  For example, we might have a slow client (or two) and
 342      * the peer server is reading far ahead and swapping to disk.  Even
 343      * if the peer aborts, we want to give the client(s)
 344      * everything we got before the abort condition occurred.
 345      */
 346     /* Warning: doCopy may indirectly free itself in callbacks,
 347      * hence the lock to keep it active for the duration of
 348      * this function
 349      * XXX: Locking does not prevent calling sc destructor (it only prevents
 350      * freeing sc memory) so sc may become invalid from C++ p.o.v.
 351      */
 352     CbcPointer<store_client> tmpLock = sc;
 353     assert (!sc->flags.store_copying);
 354     sc->doCopy(e);
 355     assert(!sc->flags.store_copying);
 356 }
 357
 358 void
 359 store_client::doCopy(StoreEntry *anEntry)
 360 {
 361     assert (anEntry == entry);
 362     flags.store_copying = true;
 363     MemObject *mem = entry->mem_obj;
 364
 365     debugs(33, 5, "store_client::doCopy: co: " <<
 366            copyInto.offset << ", hi: " <<
 367            mem->endOffset());
 368
 369     if (!moreToSend()) {
 370         /* There is no more to send! */
 371         debugs(33, 3, HERE << "There is no more to send!");
 372         callback(0);
 373         flags.store_copying = false;
 374         return;
 375     }
 376
 377     /* Check that we actually have data */
 378     if (anEntry->store_status == STORE_PENDING && copyInto.offset >= mem->endOffset()) {
 379         debugs(90, 3, "store_client::doCopy: Waiting for more");
 380         flags.store_copying = false;
 381         return;
 382     }
 383
 384     /*
 385      * Slight weirdness here.  We open a swapin file for any
 386      * STORE_DISK_CLIENT, even if we can copy the requested chunk
 387      * from memory in the next block.  We must try to open the
 388      * swapin file before sending any data to the client side.  If
 389      * we postpone the open, and then can not open the file later
 390      * on, the client loses big time.  Its transfer just gets cut
 391      * off.  Better to open it early (while the client side handler
 392      * is clientCacheHit) so that we can fall back to a cache miss
 393      * if needed.
 394      */
 395
 396     if (STORE_DISK_CLIENT == getType() && swapin_sio == NULL) {
 397         if (!startSwapin())
 398             return; // failure
 399     }
 400     scheduleRead();
 401 }
 402
 403 /// opens the swapin "file" if possible; otherwise, fail()s and returns false
 404 bool
 405 store_client::startSwapin()
 406 {
 407     debugs(90, 3, "store_client::doCopy: Need to open swap in file");
 408     /* gotta open the swapin file */
 409
 410     if (storeTooManyDiskFilesOpen()) {
 411         /* yuck -- this causes a TCP_SWAPFAIL_MISS on the client side */
 412         fail();
 413         flags.store_copying = false;
 414         return false;
 415     } else if (!flags.disk_io_pending) {
 416         /* Don't set store_io_pending here */
 417         storeSwapInStart(this);
 418
 419         if (swapin_sio == NULL) {
 420             fail();
 421             flags.store_copying = false;
 422             return false;
 423         }
 424
 425         return true;
 426     } else {
 427         debugs(90, DBG_IMPORTANT, "WARNING: Averted multiple fd operation (1)");
 428         flags.store_copying = false;
 429         return false;
 430     }
 431 }
 432
 433 void
 434 store_client::scheduleRead()
 435 {
 436     MemObject *mem = entry->mem_obj;
 437
 438     if (copyInto.offset >= mem->inmem_lo && copyInto.offset < mem->endOffset())
 439         scheduleMemRead();
 440     else
 441         scheduleDiskRead();
 442 }
 443
 444 void
 445 store_client::scheduleDiskRead()
 446 {
 447     /* What the client wants is not in memory. Schedule a disk read */
 448     if (getType() == STORE_DISK_CLIENT) {
 449         // we should have called startSwapin() already
 450         assert(swapin_sio != NULL);
 451     } else if (!swapin_sio && !startSwapin()) {
 452         debugs(90, 3, "bailing after swapin start failure for " << *entry);
 453         assert(!flags.store_copying);
 454         return;
 455     }
 456
 457     assert(!flags.disk_io_pending);
 458
 459     debugs(90, 3, "reading " << *entry << " from disk");
 460
 461     fileRead();
 462
 463     flags.store_copying = false;
 464 }
 465
 466 void
 467 store_client::scheduleMemRead()
 468 {
 469     /* What the client wants is in memory */
 470     /* Old style */
 471     debugs(90, 3, "store_client::doCopy: Copying normal from memory");
 472     size_t sz = entry->mem_obj->data_hdr.copy(copyInto);
 473     callback(sz);
 474     flags.store_copying = false;
 475 }
 476
 477 void
 478 store_client::fileRead()
 479 {
 480     MemObject *mem = entry->mem_obj;
 481
 482     assert(_callback.pending());
 483     assert(!flags.disk_io_pending);
 484     flags.disk_io_pending = true;
 485
 486     if (mem->swap_hdr_sz != 0)
 487         if (entry->swappingOut())
 488             assert(mem->swapout.sio->offset() > copyInto.offset + (int64_t)mem->swap_hdr_sz);
 489
 490     storeRead(swapin_sio,
 491               copyInto.data,
 492               copyInto.length,
 493               copyInto.offset + mem->swap_hdr_sz,
 494               mem->swap_hdr_sz == 0 ? storeClientReadHeader
 495               : storeClientReadBody,
 496               this);
 497 }
 498
 499 void
 500 store_client::readBody(const char *, ssize_t len)
 501 {
 502     int parsed_header = 0;
 503
 504     // Don't assert disk_io_pending here.. may be called by read_header
 505     flags.disk_io_pending = false;
 506     assert(_callback.pending());
 507     debugs(90, 3, "storeClientReadBody: len " << len << "");
 508
 509     if (len < 0)
 510         return fail();
 511
 512     const auto rep = entry->mem_obj ? &entry->mem().baseReply() : nullptr;
 513     if (copyInto.offset == 0 && len > 0 && rep && rep->sline.status() == Http::scNone) {
 514         /* Our structure ! */
 515         if (!entry->mem_obj->adjustableBaseReply().parseCharBuf(copyInto.data, headersEnd(copyInto.data, len))) {
 516             debugs(90, DBG_CRITICAL, "Could not parse headers from on disk object");
 517         } else {
 518             parsed_header = 1;
 519         }
 520     }
 521
 522     if (len > 0 && rep && entry->mem_obj->inmem_lo == 0 && entry->objectLen() <= (int64_t)Config.Store.maxInMemObjSize && Config.onoff.memory_cache_disk) {
 523         storeGetMemSpace(len);
 524         // The above may start to free our object so we need to check again
 525         if (entry->mem_obj->inmem_lo == 0) {
 526             /* Copy read data back into memory.
 527              * copyInto.offset includes headers, which is what mem cache needs
 528              */
 529             int64_t mem_offset = entry->mem_obj->endOffset();
 530             if ((copyInto.offset == mem_offset) || (parsed_header && mem_offset == rep->hdr_sz)) {
 531                 entry->mem_obj->write(StoreIOBuffer(len, copyInto.offset, copyInto.data));
 532             }
 533         }
 534     }
 535
 536     callback(len);
 537 }
 538
 539 void
 540 store_client::fail()
 541 {
 542     object_ok = false;
 543     /* synchronous open failures callback from the store,
 544      * before startSwapin detects the failure.
 545      * TODO: fix this inconsistent behaviour - probably by
 546      * having storeSwapInStart become a callback functions,
 547      * not synchronous
 548      */
 549
 550     if (_callback.pending())
 551         callback(0, true);
 552 }
 553
 554 static void
 555 storeClientReadHeader(void *data, const char *buf, ssize_t len, StoreIOState::Pointer)
 556 {
 557     store_client *sc = (store_client *)data;
 558     sc->readHeader(buf, len);
 559 }
 560
 561 static void
 562 storeClientReadBody(void *data, const char *buf, ssize_t len, StoreIOState::Pointer)
 563 {
 564     store_client *sc = (store_client *)data;
 565     sc->readBody(buf, len);
 566 }
 567
 568 bool
 569 store_client::unpackHeader(char const *buf, ssize_t len)
 570 {
 571     debugs(90, 3, "store_client::unpackHeader: len " << len << "");
 572     assert(len >= 0);
 573
 574     int swap_hdr_sz = 0;
 575     tlv *tlv_list = nullptr;
 576     try {
 577         StoreMetaUnpacker aBuilder(buf, len, &swap_hdr_sz);
 578         tlv_list = aBuilder.createStoreMeta();
 579     } catch (const std::exception &e) {
 580         debugs(90, DBG_IMPORTANT, "WARNING: failed to unpack metadata because " << e.what());
 581         return false;
 582     }
 583     assert(tlv_list);
 584
 585     /*
 586      * Check the meta data and make sure we got the right object.
 587      */
 588     for (tlv *t = tlv_list; t; t = t->next) {
 589         if (!t->checkConsistency(entry)) {
 590             storeSwapTLVFree(tlv_list);
 591             return false;
 592         }
 593     }
 594
 595     storeSwapTLVFree(tlv_list);
 596
 597     assert(swap_hdr_sz >= 0);
 598     entry->mem_obj->swap_hdr_sz = swap_hdr_sz;
 599     if (entry->swap_file_sz > 0) { // collapsed hits may not know swap_file_sz
 600         assert(entry->swap_file_sz >= static_cast<uint64_t>(swap_hdr_sz));
 601         entry->mem_obj->object_sz = entry->swap_file_sz - swap_hdr_sz;
 602     }
 603     debugs(90, 5, "store_client::unpackHeader: swap_file_sz=" <<
 604            entry->swap_file_sz << "( " << swap_hdr_sz << " + " <<
 605            entry->mem_obj->object_sz << ")");
 606     return true;
 607 }
 608
 609 void
 610 store_client::readHeader(char const *buf, ssize_t len)
 611 {
 612     MemObject *const mem = entry->mem_obj;
 613
 614     assert(flags.disk_io_pending);
 615     flags.disk_io_pending = false;
 616     assert(_callback.pending());
 617
 618     // abort if we fail()'d earlier
 619     if (!object_ok)
 620         return;
 621
 622     if (len < 0)
 623         return fail();
 624
 625     if (!unpackHeader(buf, len)) {
 626         fail();
 627         return;
 628     }
 629
 630     /*
 631      * If our last read got some data the client wants, then give
 632      * it to them, otherwise schedule another read.
 633      */
 634     size_t body_sz = len - mem->swap_hdr_sz;
 635
 636     if (copyInto.offset < static_cast<int64_t>(body_sz)) {
 637         /*
 638          * we have (part of) what they want
 639          */
 640         size_t copy_sz = min(copyInto.length, body_sz);
 641         debugs(90, 3, "storeClientReadHeader: copying " << copy_sz << " bytes of body");
 642         memmove(copyInto.data, copyInto.data + mem->swap_hdr_sz, copy_sz);
 643
 644         readBody(copyInto.data, copy_sz);
 645
 646         return;
 647     }
 648
 649     /*
 650      * we don't have what the client wants, but at least we now
 651      * know the swap header size.
 652      */
 653     fileRead();
 654 }
 655
 656 int
 657 storeClientCopyPending(store_client * sc, StoreEntry * e, void *data)
 658 {
 659 #if STORE_CLIENT_LIST_DEBUG
 660     assert(sc == storeClientListSearch(e->mem_obj, data));
 661 #endif
 662 #ifndef SILLY_CODE
 663
 664     assert(sc);
 665 #endif
 666
 667     assert(sc->entry == e);
 668 #if SILLY_CODE
 669
 670     if (sc == NULL)
 671         return 0;
 672
 673 #endif
 674
 675     if (!sc->_callback.pending())
 676         return 0;
 677
 678     return 1;
 679 }
 680
 681 /*
 682  * This routine hasn't been optimised to take advantage of the
 683  * passed sc. Yet.
 684  */
 685 int
 686 storeUnregister(store_client * sc, StoreEntry * e, void *data)
 687 {
 688     MemObject *mem = e->mem_obj;
 689 #if STORE_CLIENT_LIST_DEBUG
 690
 691     assert(sc == storeClientListSearch(e->mem_obj, data));
 692 #endif
 693
 694     if (mem == NULL)
 695         return 0;
 696
 697     debugs(90, 3, "storeUnregister: called for '" << e->getMD5Text() << "'");
 698
 699     if (sc == NULL) {
 700         debugs(90, 3, "storeUnregister: No matching client for '" << e->getMD5Text() << "'");
 701         return 0;
 702     }
 703
 704     if (mem->clientCount() == 0) {
 705         debugs(90, 3, "storeUnregister: Consistency failure - store client being unregistered is not in the mem object's list for '" << e->getMD5Text() << "'");
 706         return 0;
 707     }
 708
 709     dlinkDelete(&sc->node, &mem->clients);
 710     -- mem->nclients;
 711
 712     const auto swapoutFinished = e->swappedOut() || e->swapoutFailed();
 713     if (e->store_status == STORE_OK && !swapoutFinished)
 714         e->swapOut();
 715
 716     if (sc->swapin_sio != NULL) {
 717         storeClose(sc->swapin_sio, StoreIOState::readerDone);
 718         sc->swapin_sio = NULL;
 719         ++statCounter.swap.ins;
 720     }
 721
 722     if (sc->_callback.pending()) {
 723         /* callback with ssize = -1 to indicate unexpected termination */
 724         debugs(90, 3, "store_client for " << *e << " has a callback");
 725         sc->fail();
 726     }
 727
 728 #if STORE_CLIENT_LIST_DEBUG
 729     cbdataReferenceDone(sc->owner);
 730
 731 #endif
 732
 733     delete sc;
 734
 735     assert(e->locked());
 736     // An entry locked by others may be unlocked (and destructed) by others, so
 737     // we must lock again to safely dereference e after CheckQuickAbortIsReasonable().
 738     e->lock("storeUnregister");
 739
 740     if (CheckQuickAbortIsReasonable(e))
 741         e->abort();
 742     else
 743         mem->kickReads();
 744
 745 #if USE_ADAPTATION
 746     e->kickProducer();
 747 #endif
 748
 749     e->unlock("storeUnregister");
 750     return 1;
 751 }
 752
 753 /* Call handlers waiting for  data to be appended to E. */
 754 void
 755 StoreEntry::invokeHandlers()
 756 {
 757     if (EBIT_TEST(flags, DELAY_SENDING)) {
 758         debugs(90, 3, "DELAY_SENDING is on, exiting " << *this);
 759         return;
 760     }
 761     if (EBIT_TEST(flags, ENTRY_FWD_HDR_WAIT)) {
 762         debugs(90, 3, "ENTRY_FWD_HDR_WAIT is on, exiting " << *this);
 763         return;
 764     }
 765
 766     /* Commit what we can to disk, if appropriate */
 767     swapOut();
 768     int i = 0;
 769     store_client *sc;
 770     dlink_node *nx = NULL;
 771     dlink_node *node;
 772
 773     PROF_start(InvokeHandlers);
 774
 775     debugs(90, 3, "InvokeHandlers: " << getMD5Text()  );
 776     /* walk the entire list looking for valid callbacks */
 777
 778     for (node = mem_obj->clients.head; node; node = nx) {
 779         sc = (store_client *)node->data;
 780         nx = node->next;
 781         debugs(90, 3, "StoreEntry::InvokeHandlers: checking client #" << i  );
 782         ++i;
 783
 784         if (!sc->_callback.pending())
 785             continue;
 786
 787         if (sc->flags.disk_io_pending)
 788             continue;
 789
 790         storeClientCopy2(this, sc);
 791     }
 792     PROF_stop(InvokeHandlers);
 793 }
 794
 795 // Does not account for remote readers/clients.
 796 int
 797 storePendingNClients(const StoreEntry * e)
 798 {
 799     MemObject *mem = e->mem_obj;
 800     int npend = NULL == mem ? 0 : mem->nclients;
 801     debugs(90, 3, "storePendingNClients: returning " << npend);
 802     return npend;
 803 }
 804
 805 /* return true if the request should be aborted */
 806 static bool
 807 CheckQuickAbortIsReasonable(StoreEntry * entry)
 808 {
 809     assert(entry);
 810     debugs(90, 3, "entry=" << *entry);
 811
 812     if (storePendingNClients(entry) > 0) {
 813         debugs(90, 3, "quick-abort? NO storePendingNClients() > 0");
 814         return false;
 815     }
 816
 817     if (!shutting_down && Store::Root().transientReaders(*entry)) {
 818         debugs(90, 3, "quick-abort? NO still have one or more transient readers");
 819         return false;
 820     }
 821
 822     if (entry->store_status != STORE_PENDING) {
 823         debugs(90, 3, "quick-abort? NO store_status != STORE_PENDING");
 824         return false;
 825     }
 826
 827     if (EBIT_TEST(entry->flags, ENTRY_SPECIAL)) {
 828         debugs(90, 3, "quick-abort? NO ENTRY_SPECIAL");
 829         return false;
 830     }
 831
 832     MemObject * const mem = entry->mem_obj;
 833     assert(mem);
 834     debugs(90, 3, "mem=" << mem);
 835
 836     if (mem->request && !mem->request->flags.cachable) {
 837         debugs(90, 3, "quick-abort? YES !mem->request->flags.cachable");
 838         return true;
 839     }
 840
 841     if (EBIT_TEST(entry->flags, KEY_PRIVATE)) {
 842         debugs(90, 3, "quick-abort? YES KEY_PRIVATE");
 843         return true;
 844     }
 845
 846     const auto &reply = mem->baseReply();
 847
 848     if (reply.hdr_sz <= 0) {
 849         // TODO: Check whether this condition works for HTTP/0 responses.
 850         debugs(90, 3, "quick-abort? YES no object data received yet");
 851         return true;
 852     }
 853
 854     if (Config.quickAbort.min < 0) {
 855         debugs(90, 3, "quick-abort? NO disabled");
 856         return false;
 857     }
 858
 859     if (mem->request && mem->request->range && mem->request->getRangeOffsetLimit() < 0) {
 860         // the admin has configured "range_offset_limit none"
 861         debugs(90, 3, "quick-abort? NO admin configured range replies to full-download");
 862         return false;
 863     }
 864
 865     if (reply.content_length < 0) {
 866         // XXX: cf.data.pre does not document what should happen in this case
 867         // We know that quick_abort is enabled, but no limit can be applied.
 868         debugs(90, 3, "quick-abort? YES unknown content length");
 869         return true;
 870     }
 871     const auto expectlen = reply.hdr_sz + reply.content_length;
 872
 873     int64_t curlen =  mem->endOffset();
 874
 875     if (curlen > expectlen) {
 876         debugs(90, 3, "quick-abort? YES bad content length (" << curlen << " of " << expectlen << " bytes received)");
 877         return true;
 878     }
 879
 880     if ((expectlen - curlen) < (Config.quickAbort.min << 10)) {
 881         debugs(90, 3, "quick-abort? NO only a little more object left to receive");
 882         return false;
 883     }
 884
 885     if ((expectlen - curlen) > (Config.quickAbort.max << 10)) {
 886         debugs(90, 3, "quick-abort? YES too much left to go");
 887         return true;
 888     }
 889
 890     // XXX: This is absurd! TODO: For positives, "a/(b/c) > d" is "a*c > b*d".
 891     if (expectlen < 100) {
 892         debugs(90, 3, "quick-abort? NO avoid FPE");
 893         return false;
 894     }
 895
 896     if ((curlen / (expectlen / 100)) > (Config.quickAbort.pct)) {
 897         debugs(90, 3, "quick-abort? NO past point of no return");
 898         return false;
 899     }
 900
 901     debugs(90, 3, "quick-abort? YES default");
 902     return true;
 903 }
 904
 905 void
 906 store_client::dumpStats(MemBuf * output, int clientNumber) const
 907 {
 908     if (_callback.pending())
 909         return;
 910
 911     output->appendf("\tClient #%d, %p\n", clientNumber, _callback.callback_data);
 912     output->appendf("\t\tcopy_offset: %" PRId64 "\n", copyInto.offset);
 913     output->appendf("\t\tcopy_size: %" PRIuSIZE "\n", copyInto.length);
 914     output->append("\t\tflags:", 8);
 915
 916     if (flags.disk_io_pending)
 917         output->append(" disk_io_pending", 16);
 918
 919     if (flags.store_copying)
 920         output->append(" store_copying", 14);
 921
 922     if (flags.copy_event_pending)
 923         output->append(" copy_event_pending", 19);
 924
 925     output->append("\n",1);
 926 }
 927
 928 bool
 929 store_client::Callback::pending() const
 930 {
 931     return callback_handler && callback_data;
 932 }
 933
 934 store_client::Callback::Callback(STCB *function, void *data) : callback_handler(function), callback_data (data) {}
 935
 936 #if USE_DELAY_POOLS
 937 void
 938 store_client::setDelayId(DelayId delay_id)
 939 {
 940     delayId = delay_id;
 941 }
 942 #endif
 943