src/helper.cc

   1 /*
   2  * DEBUG: section 84    Helper process maintenance
   3  * AUTHOR: Harvest Derived?
   4  *
   5  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   6  * ----------------------------------------------------------
   7  *
   8  *  Squid is the result of efforts by numerous individuals from
   9  *  the Internet community; see the CONTRIBUTORS file for full
  10  *  details.   Many organizations have provided support for Squid's
  11  *  development; see the SPONSORS file for full details.  Squid is
  12  *  Copyrighted (C) 2001 by the Regents of the University of
  13  *  California; see the COPYRIGHT file for full details.  Squid
  14  *  incorporates software developed and/or copyrighted by other
  15  *  sources; see the CREDITS file for full details.
  16  *
  17  *  This program is free software; you can redistribute it and/or modify
  18  *  it under the terms of the GNU General Public License as published by
  19  *  the Free Software Foundation; either version 2 of the License, or
  20  *  (at your option) any later version.
  21  *
  22  *  This program is distributed in the hope that it will be useful,
  23  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  *  GNU General Public License for more details.
  26  *
  27  *  You should have received a copy of the GNU General Public License
  28  *  along with this program; if not, write to the Free Software
  29  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  30  *
  31  */
  32
  33 #include "squid.h"
  34 #include "base/AsyncCbdataCalls.h"
  35 #include "comm.h"
  36 #include "comm/Connection.h"
  37 #include "comm/Write.h"
  38 #include "fd.h"
  39 #include "format/Quoting.h"
  40 #include "helper.h"
  41 #include "Mem.h"
  42 #include "MemBuf.h"
  43 #include "SquidIpc.h"
  44 #include "SquidMath.h"
  45 #include "SquidTime.h"
  46 #include "Store.h"
  47 #include "wordlist.h"
  48
  49 #define HELPER_MAX_ARGS 64
  50
  51 /** Initial Squid input buffer size. Helper responses may exceed this, and
  52  * Squid will grow the input buffer as needed, up to ReadBufMaxSize.
  53  */
  54 const size_t ReadBufMinSize(4*1024);
  55
  56 /** Maximum safe size of a helper-to-Squid response message plus one.
  57  * Squid will warn and close the stream if a helper sends a too-big response.
  58  * ssl_crtd helper is known to produce responses of at least 10KB in size.
  59  * Some undocumented helpers are known to produce responses exceeding 8KB.
  60  */
  61 const size_t ReadBufMaxSize(32*1024);
  62
  63 static IOCB helperHandleRead;
  64 static IOCB helperStatefulHandleRead;
  65 static void helperServerFree(helper_server *srv);
  66 static void helperStatefulServerFree(helper_stateful_server *srv);
  67 static void Enqueue(helper * hlp, helper_request *);
  68 static helper_request *Dequeue(helper * hlp);
  69 static helper_stateful_request *StatefulDequeue(statefulhelper * hlp);
  70 static helper_server *GetFirstAvailable(helper * hlp);
  71 static helper_stateful_server *StatefulGetFirstAvailable(statefulhelper * hlp);
  72 static void helperDispatch(helper_server * srv, helper_request * r);
  73 static void helperStatefulDispatch(helper_stateful_server * srv, helper_stateful_request * r);
  74 static void helperKickQueue(helper * hlp);
  75 static void helperStatefulKickQueue(statefulhelper * hlp);
  76 static void helperStatefulServerDone(helper_stateful_server * srv);
  77 static void helperRequestFree(helper_request * r);
  78 static void helperStatefulRequestFree(helper_stateful_request * r);
  79 static void StatefulEnqueue(statefulhelper * hlp, helper_stateful_request * r);
  80 static bool helperStartStats(StoreEntry *sentry, void *hlp, const char *label);
  81
  82 CBDATA_CLASS_INIT(helper);
  83 CBDATA_TYPE(helper_server);
  84 CBDATA_CLASS_INIT(statefulhelper);
  85 CBDATA_TYPE(helper_stateful_server);
  86
  87 void
  88 HelperServerBase::initStats()
  89 {
  90     stats.uses=0;
  91     stats.replies=0;
  92     stats.pending=0;
  93     stats.releases=0;
  94 }
  95
  96 void
  97 HelperServerBase::closePipesSafely()
  98 {
  99 #if _SQUID_WINDOWS_
 100     int no = index + 1;
 101
 102     shutdown(writePipe->fd, SD_BOTH);
 103 #endif
 104
 105     flags.closing = 1;
 106     if (readPipe->fd == writePipe->fd)
 107         readPipe->fd = -1;
 108     else
 109         readPipe->close();
 110     writePipe->close();
 111
 112 #if _SQUID_WINDOWS_
 113     if (hIpc) {
 114         if (WaitForSingleObject(hIpc, 5000) != WAIT_OBJECT_0) {
 115             getCurrentTime();
 116             debugs(84, DBG_IMPORTANT, "WARNING: " << hlp->id_name <<
 117                    " #" << no << " (" << hlp->cmdline->key << "," <<
 118                    (long int)pid << ") didn't exit in 5 seconds");
 119         }
 120         CloseHandle(hIpc);
 121     }
 122 #endif
 123 }
 124
 125 void
 126 HelperServerBase::closeWritePipeSafely()
 127 {
 128 #if _SQUID_WINDOWS_
 129     int no = index + 1;
 130
 131     shutdown(writePipe->fd, (readPipe->fd == writePipe->fd ? SD_BOTH : SD_SEND));
 132 #endif
 133
 134     flags.closing = 1;
 135     if (readPipe->fd == writePipe->fd)
 136         readPipe->fd = -1;
 137     writePipe->close();
 138
 139 #if _SQUID_WINDOWS_
 140     if (hIpc) {
 141         if (WaitForSingleObject(hIpc, 5000) != WAIT_OBJECT_0) {
 142             getCurrentTime();
 143             debugs(84, DBG_IMPORTANT, "WARNING: " << hlp->id_name <<
 144                    " #" << no << " (" << hlp->cmdline->key << "," <<
 145                    (long int)pid << ") didn't exit in 5 seconds");
 146         }
 147         CloseHandle(hIpc);
 148     }
 149 #endif
 150 }
 151
 152 void
 153 helperOpenServers(helper * hlp)
 154 {
 155     char *s;
 156     char *progname;
 157     char *shortname;
 158     char *procname;
 159     const char *args[HELPER_MAX_ARGS+1]; // save space for a NULL terminator
 160     char fd_note_buf[FD_DESC_SZ];
 161     helper_server *srv;
 162     int nargs = 0;
 163     int k;
 164     pid_t pid;
 165     int rfd;
 166     int wfd;
 167     void * hIpc;
 168     wordlist *w;
 169
 170     if (hlp->cmdline == NULL)
 171         return;
 172
 173     progname = hlp->cmdline->key;
 174
 175     if ((s = strrchr(progname, '/')))
 176         shortname = xstrdup(s + 1);
 177     else
 178         shortname = xstrdup(progname);
 179
 180     /* figure out how many new child are actually needed. */
 181     int need_new = hlp->childs.needNew();
 182
 183     debugs(84, DBG_IMPORTANT, "helperOpenServers: Starting " << need_new << "/" << hlp->childs.n_max << " '" << shortname << "' processes");
 184
 185     if (need_new < 1) {
 186         debugs(84, DBG_IMPORTANT, "helperOpenServers: No '" << shortname << "' processes needed.");
 187     }
 188
 189     procname = (char *)xmalloc(strlen(shortname) + 3);
 190
 191     snprintf(procname, strlen(shortname) + 3, "(%s)", shortname);
 192
 193     args[nargs] = procname;
 194     ++nargs;
 195
 196     for (w = hlp->cmdline->next; w && nargs < HELPER_MAX_ARGS; w = w->next) {
 197         args[nargs] = w->key;
 198         ++nargs;
 199     }
 200
 201     args[nargs] = NULL;
 202     ++nargs;
 203
 204     assert(nargs <= HELPER_MAX_ARGS);
 205
 206     for (k = 0; k < need_new; ++k) {
 207         getCurrentTime();
 208         rfd = wfd = -1;
 209         pid = ipcCreate(hlp->ipc_type,
 210                         progname,
 211                         args,
 212                         shortname,
 213                         hlp->addr,
 214                         &rfd,
 215                         &wfd,
 216                         &hIpc);
 217
 218         if (pid < 0) {
 219             debugs(84, DBG_IMPORTANT, "WARNING: Cannot run '" << progname << "' process.");
 220             continue;
 221         }
 222
 223         ++ hlp->childs.n_running;
 224         ++ hlp->childs.n_active;
 225         CBDATA_INIT_TYPE(helper_server);
 226         srv = cbdataAlloc(helper_server);
 227         srv->hIpc = hIpc;
 228         srv->pid = pid;
 229         srv->initStats();
 230         srv->index = k;
 231         srv->addr = hlp->addr;
 232         srv->readPipe = new Comm::Connection;
 233         srv->readPipe->fd = rfd;
 234         srv->writePipe = new Comm::Connection;
 235         srv->writePipe->fd = wfd;
 236         srv->rbuf = (char *)memAllocBuf(ReadBufMinSize, &srv->rbuf_sz);
 237         srv->wqueue = new MemBuf;
 238         srv->roffset = 0;
 239         srv->requests = (helper_request **)xcalloc(hlp->childs.concurrency ? hlp->childs.concurrency : 1, sizeof(*srv->requests));
 240         srv->parent = cbdataReference(hlp);
 241         dlinkAddTail(srv, &srv->link, &hlp->servers);
 242
 243         if (rfd == wfd) {
 244             snprintf(fd_note_buf, FD_DESC_SZ, "%s #%d", shortname, k + 1);
 245             fd_note(rfd, fd_note_buf);
 246         } else {
 247             snprintf(fd_note_buf, FD_DESC_SZ, "reading %s #%d", shortname, k + 1);
 248             fd_note(rfd, fd_note_buf);
 249             snprintf(fd_note_buf, FD_DESC_SZ, "writing %s #%d", shortname, k + 1);
 250             fd_note(wfd, fd_note_buf);
 251         }
 252
 253         commSetNonBlocking(rfd);
 254
 255         if (wfd != rfd)
 256             commSetNonBlocking(wfd);
 257
 258         AsyncCall::Pointer closeCall = asyncCall(5,4, "helperServerFree", cbdataDialer(helperServerFree, srv));
 259         comm_add_close_handler(rfd, closeCall);
 260
 261         AsyncCall::Pointer call = commCbCall(5,4, "helperHandleRead",
 262                                              CommIoCbPtrFun(helperHandleRead, srv));
 263         comm_read(srv->readPipe, srv->rbuf, srv->rbuf_sz - 1, call);
 264     }
 265
 266     hlp->last_restart = squid_curtime;
 267     safe_free(shortname);
 268     safe_free(procname);
 269     helperKickQueue(hlp);
 270 }
 271
 272 /**
 273  * DPW 2007-05-08
 274  *
 275  * helperStatefulOpenServers: create the stateful child helper processes
 276  */
 277 void
 278 helperStatefulOpenServers(statefulhelper * hlp)
 279 {
 280     char *shortname;
 281     const char *args[HELPER_MAX_ARGS+1]; // save space for a NULL terminator
 282     char fd_note_buf[FD_DESC_SZ];
 283     int nargs = 0;
 284
 285     if (hlp->cmdline == NULL)
 286         return;
 287
 288     if (hlp->childs.concurrency)
 289         debugs(84, DBG_CRITICAL, "ERROR: concurrency= is not yet supported for stateful helpers ('" << hlp->cmdline << "')");
 290
 291     char *progname = hlp->cmdline->key;
 292
 293     char *s;
 294     if ((s = strrchr(progname, '/')))
 295         shortname = xstrdup(s + 1);
 296     else
 297         shortname = xstrdup(progname);
 298
 299     /* figure out haw mant new helpers are needed. */
 300     int need_new = hlp->childs.needNew();
 301
 302     debugs(84, DBG_IMPORTANT, "helperOpenServers: Starting " << need_new << "/" << hlp->childs.n_max << " '" << shortname << "' processes");
 303
 304     if (need_new < 1) {
 305         debugs(84, DBG_IMPORTANT, "helperStatefulOpenServers: No '" << shortname << "' processes needed.");
 306     }
 307
 308     char *procname = (char *)xmalloc(strlen(shortname) + 3);
 309
 310     snprintf(procname, strlen(shortname) + 3, "(%s)", shortname);
 311
 312     args[nargs] = procname;
 313     ++nargs;
 314
 315     for (wordlist *w = hlp->cmdline->next; w && nargs < HELPER_MAX_ARGS; w = w->next) {
 316         args[nargs] = w->key;
 317         ++nargs;
 318     }
 319
 320     args[nargs] = NULL;
 321     ++nargs;
 322
 323     assert(nargs <= HELPER_MAX_ARGS);
 324
 325     for (int k = 0; k < need_new; ++k) {
 326         getCurrentTime();
 327         int rfd = -1;
 328         int wfd = -1;
 329         void * hIpc;
 330         pid_t pid = ipcCreate(hlp->ipc_type,
 331                               progname,
 332                               args,
 333                               shortname,
 334                               hlp->addr,
 335                               &rfd,
 336                               &wfd,
 337                               &hIpc);
 338
 339         if (pid < 0) {
 340             debugs(84, DBG_IMPORTANT, "WARNING: Cannot run '" << progname << "' process.");
 341             continue;
 342         }
 343
 344         ++ hlp->childs.n_running;
 345         ++ hlp->childs.n_active;
 346         CBDATA_INIT_TYPE(helper_stateful_server);
 347         helper_stateful_server *srv = cbdataAlloc(helper_stateful_server);
 348         srv->hIpc = hIpc;
 349         srv->pid = pid;
 350         srv->flags.reserved = 0;
 351         srv->initStats();
 352         srv->index = k;
 353         srv->addr = hlp->addr;
 354         srv->readPipe = new Comm::Connection;
 355         srv->readPipe->fd = rfd;
 356         srv->writePipe = new Comm::Connection;
 357         srv->writePipe->fd = wfd;
 358         srv->rbuf = (char *)memAllocBuf(ReadBufMinSize, &srv->rbuf_sz);
 359         srv->roffset = 0;
 360         srv->parent = cbdataReference(hlp);
 361
 362         if (hlp->datapool != NULL)
 363             srv->data = hlp->datapool->alloc();
 364
 365         dlinkAddTail(srv, &srv->link, &hlp->servers);
 366
 367         if (rfd == wfd) {
 368             snprintf(fd_note_buf, FD_DESC_SZ, "%s #%d", shortname, k + 1);
 369             fd_note(rfd, fd_note_buf);
 370         } else {
 371             snprintf(fd_note_buf, FD_DESC_SZ, "reading %s #%d", shortname, k + 1);
 372             fd_note(rfd, fd_note_buf);
 373             snprintf(fd_note_buf, FD_DESC_SZ, "writing %s #%d", shortname, k + 1);
 374             fd_note(wfd, fd_note_buf);
 375         }
 376
 377         commSetNonBlocking(rfd);
 378
 379         if (wfd != rfd)
 380             commSetNonBlocking(wfd);
 381
 382         AsyncCall::Pointer closeCall = asyncCall(5,4, "helperStatefulServerFree", cbdataDialer(helperStatefulServerFree, srv));
 383         comm_add_close_handler(rfd, closeCall);
 384
 385         AsyncCall::Pointer call = commCbCall(5,4, "helperStatefulHandleRead",
 386                                              CommIoCbPtrFun(helperStatefulHandleRead, srv));
 387         comm_read(srv->readPipe, srv->rbuf, srv->rbuf_sz - 1, call);
 388     }
 389
 390     hlp->last_restart = squid_curtime;
 391     safe_free(shortname);
 392     safe_free(procname);
 393     helperStatefulKickQueue(hlp);
 394 }
 395
 396 void
 397 helperSubmit(helper * hlp, const char *buf, HLPCB * callback, void *data)
 398 {
 399     if (hlp == NULL) {
 400         debugs(84, 3, "helperSubmit: hlp == NULL");
 401         HelperReply nilReply;
 402         callback(data, nilReply);
 403         return;
 404     }
 405
 406     helper_request *r = new helper_request;
 407     helper_server *srv;
 408
 409     r->callback = callback;
 410     r->data = cbdataReference(data);
 411     r->buf = xstrdup(buf);
 412
 413     if ((srv = GetFirstAvailable(hlp)))
 414         helperDispatch(srv, r);
 415     else
 416         Enqueue(hlp, r);
 417
 418     debugs(84, 9, "helperSubmit: " << buf);
 419 }
 420
 421 /// lastserver = "server last used as part of a reserved request sequence"
 422 void
 423 helperStatefulSubmit(statefulhelper * hlp, const char *buf, HLPCB * callback, void *data, helper_stateful_server * lastserver)
 424 {
 425     if (hlp == NULL) {
 426         debugs(84, 3, "helperStatefulSubmit: hlp == NULL");
 427         HelperReply nilReply;
 428         callback(data, nilReply);
 429         return;
 430     }
 431
 432     helper_stateful_request *r = new helper_stateful_request;
 433
 434     r->callback = callback;
 435     r->data = cbdataReference(data);
 436
 437     if (buf != NULL) {
 438         r->buf = xstrdup(buf);
 439         r->placeholder = 0;
 440     } else {
 441         r->buf = NULL;
 442         r->placeholder = 1;
 443     }
 444
 445     if ((buf != NULL) && lastserver) {
 446         debugs(84, 5, "StatefulSubmit with lastserver " << lastserver);
 447         assert(lastserver->flags.reserved);
 448         assert(!(lastserver->request));
 449
 450         debugs(84, 5, "StatefulSubmit dispatching");
 451         helperStatefulDispatch(lastserver, r);
 452     } else {
 453         helper_stateful_server *srv;
 454         if ((srv = StatefulGetFirstAvailable(hlp))) {
 455             helperStatefulDispatch(srv, r);
 456         } else
 457             StatefulEnqueue(hlp, r);
 458     }
 459
 460     debugs(84, 9, "helperStatefulSubmit: placeholder: '" << r->placeholder << "', buf '" << buf << "'.");
 461 }
 462
 463 /**
 464  * DPW 2007-05-08
 465  *
 466  * helperStatefulReleaseServer tells the helper that whoever was
 467  * using it no longer needs its services.
 468  */
 469 void
 470 helperStatefulReleaseServer(helper_stateful_server * srv)
 471 {
 472     debugs(84, 3, HERE << "srv-" << srv->index << " flags.reserved = " << srv->flags.reserved);
 473     if (!srv->flags.reserved)
 474         return;
 475
 476     ++ srv->stats.releases;
 477
 478     srv->flags.reserved = 0;
 479     if (srv->parent->OnEmptyQueue != NULL && srv->data)
 480         srv->parent->OnEmptyQueue(srv->data);
 481
 482     helperStatefulServerDone(srv);
 483 }
 484
 485 /** return a pointer to the stateful routines data area */
 486 void *
 487 helperStatefulServerGetData(helper_stateful_server * srv)
 488 {
 489     return srv->data;
 490 }
 491
 492 /**
 493  * Dump some stats about the helper states to a StoreEntry
 494  */
 495 void
 496 helperStats(StoreEntry * sentry, helper * hlp, const char *label)
 497 {
 498     if (!helperStartStats(sentry, hlp, label))
 499         return;
 500
 501     storeAppendPrintf(sentry, "program: %s\n",
 502                       hlp->cmdline->key);
 503     storeAppendPrintf(sentry, "number active: %d of %d (%d shutting down)\n",
 504                       hlp->childs.n_active, hlp->childs.n_max, (hlp->childs.n_running - hlp->childs.n_active) );
 505     storeAppendPrintf(sentry, "requests sent: %d\n",
 506                       hlp->stats.requests);
 507     storeAppendPrintf(sentry, "replies received: %d\n",
 508                       hlp->stats.replies);
 509     storeAppendPrintf(sentry, "queue length: %d\n",
 510                       hlp->stats.queue_size);
 511     storeAppendPrintf(sentry, "avg service time: %d msec\n",
 512                       hlp->stats.avg_svc_time);
 513     storeAppendPrintf(sentry, "\n");
 514     storeAppendPrintf(sentry, "%7s\t%7s\t%7s\t%11s\t%11s\t%s\t%7s\t%7s\t%7s\n",
 515                       "#",
 516                       "FD",
 517                       "PID",
 518                       "# Requests",
 519                       "# Replies",
 520                       "Flags",
 521                       "Time",
 522                       "Offset",
 523                       "Request");
 524
 525     for (dlink_node *link = hlp->servers.head; link; link = link->next) {
 526         helper_server *srv = (helper_server*)link->data;
 527         double tt = 0.001 * (srv->requests[0] ? tvSubMsec(srv->requests[0]->dispatch_time, current_time) : tvSubMsec(srv->dispatch_time, srv->answer_time));
 528         storeAppendPrintf(sentry, "%7d\t%7d\t%7d\t%11" PRIu64 "\t%11" PRIu64 "%c%c%c%c\t%7.3f\t%7d\t%s\n",
 529                           srv->index + 1,
 530                           srv->readPipe->fd,
 531                           srv->pid,
 532                           srv->stats.uses,
 533                           srv->stats.replies,
 534                           srv->stats.pending ? 'B' : ' ',
 535                           srv->flags.writing ? 'W' : ' ',
 536                           srv->flags.closing ? 'C' : ' ',
 537                           srv->flags.shutdown ? 'S' : ' ',
 538                           tt < 0.0 ? 0.0 : tt,
 539                           (int) srv->roffset,
 540                           srv->requests[0] ? Format::QuoteMimeBlob(srv->requests[0]->buf) : "(none)");
 541     }
 542
 543     storeAppendPrintf(sentry, "\nFlags key:\n\n");
 544     storeAppendPrintf(sentry, "   B = BUSY\n");
 545     storeAppendPrintf(sentry, "   W = WRITING\n");
 546     storeAppendPrintf(sentry, "   C = CLOSING\n");
 547     storeAppendPrintf(sentry, "   S = SHUTDOWN PENDING\n");
 548 }
 549
 550 void
 551 helperStatefulStats(StoreEntry * sentry, statefulhelper * hlp, const char *label)
 552 {
 553     if (!helperStartStats(sentry, hlp, label))
 554         return;
 555
 556     storeAppendPrintf(sentry, "program: %s\n",
 557                       hlp->cmdline->key);
 558     storeAppendPrintf(sentry, "number active: %d of %d (%d shutting down)\n",
 559                       hlp->childs.n_active, hlp->childs.n_max, (hlp->childs.n_running - hlp->childs.n_active) );
 560     storeAppendPrintf(sentry, "requests sent: %d\n",
 561                       hlp->stats.requests);
 562     storeAppendPrintf(sentry, "replies received: %d\n",
 563                       hlp->stats.replies);
 564     storeAppendPrintf(sentry, "queue length: %d\n",
 565                       hlp->stats.queue_size);
 566     storeAppendPrintf(sentry, "avg service time: %d msec\n",
 567                       hlp->stats.avg_svc_time);
 568     storeAppendPrintf(sentry, "\n");
 569     storeAppendPrintf(sentry, "%7s\t%7s\t%7s\t%11s\t%11s\t%6s\t%7s\t%7s\t%7s\n",
 570                       "#",
 571                       "FD",
 572                       "PID",
 573                       "# Requests",
 574                       "# Replies",
 575                       "Flags",
 576                       "Time",
 577                       "Offset",
 578                       "Request");
 579
 580     for (dlink_node *link = hlp->servers.head; link; link = link->next) {
 581         helper_stateful_server *srv = (helper_stateful_server *)link->data;
 582         double tt = 0.001 * tvSubMsec(srv->dispatch_time, srv->flags.busy ? current_time : srv->answer_time);
 583         storeAppendPrintf(sentry, "%7d\t%7d\t%7d\t%11" PRIu64 "\t%11" PRIu64 "\t%c%c%c%c%c\t%7.3f\t%7d\t%s\n",
 584                           srv->index + 1,
 585                           srv->readPipe->fd,
 586                           srv->pid,
 587                           srv->stats.uses,
 588                           srv->stats.replies,
 589                           srv->flags.busy ? 'B' : ' ',
 590                           srv->flags.closing ? 'C' : ' ',
 591                           srv->flags.reserved ? 'R' : ' ',
 592                           srv->flags.shutdown ? 'S' : ' ',
 593                           srv->request ? (srv->request->placeholder ? 'P' : ' ') : ' ',
 594                                   tt < 0.0 ? 0.0 : tt,
 595                                   (int) srv->roffset,
 596                                   srv->request ? Format::QuoteMimeBlob(srv->request->buf) : "(none)");
 597     }
 598
 599     storeAppendPrintf(sentry, "\nFlags key:\n\n");
 600     storeAppendPrintf(sentry, "   B = BUSY\n");
 601     storeAppendPrintf(sentry, "   C = CLOSING\n");
 602     storeAppendPrintf(sentry, "   R = RESERVED\n");
 603     storeAppendPrintf(sentry, "   S = SHUTDOWN PENDING\n");
 604     storeAppendPrintf(sentry, "   P = PLACEHOLDER\n");
 605 }
 606
 607 void
 608 helperShutdown(helper * hlp)
 609 {
 610     dlink_node *link = hlp->servers.head;
 611
 612     while (link) {
 613         helper_server *srv;
 614         srv = (helper_server *)link->data;
 615         link = link->next;
 616
 617         if (srv->flags.shutdown) {
 618             debugs(84, 3, "helperShutdown: " << hlp->id_name << " #" << srv->index + 1 << " has already SHUT DOWN.");
 619             continue;
 620         }
 621
 622         assert(hlp->childs.n_active > 0);
 623         -- hlp->childs.n_active;
 624         srv->flags.shutdown = 1;        /* request it to shut itself down */
 625
 626         if (srv->flags.closing) {
 627             debugs(84, 3, "helperShutdown: " << hlp->id_name << " #" << srv->index + 1 << " is CLOSING.");
 628             continue;
 629         }
 630
 631         if (srv->stats.pending) {
 632             debugs(84, 3, "helperShutdown: " << hlp->id_name << " #" << srv->index + 1 << " is BUSY.");
 633             continue;
 634         }
 635
 636         debugs(84, 3, "helperShutdown: " << hlp->id_name << " #" << srv->index + 1 << " shutting down.");
 637         /* the rest of the details is dealt with in the helperServerFree
 638          * close handler
 639          */
 640         srv->closePipesSafely();
 641     }
 642 }
 643
 644 void
 645 helperStatefulShutdown(statefulhelper * hlp)
 646 {
 647     dlink_node *link = hlp->servers.head;
 648     helper_stateful_server *srv;
 649
 650     while (link) {
 651         srv = (helper_stateful_server *)link->data;
 652         link = link->next;
 653
 654         if (srv->flags.shutdown) {
 655             debugs(84, 3, "helperStatefulShutdown: " << hlp->id_name << " #" << srv->index + 1 << " has already SHUT DOWN.");
 656             continue;
 657         }
 658
 659         assert(hlp->childs.n_active > 0);
 660         -- hlp->childs.n_active;
 661         srv->flags.shutdown = 1;        /* request it to shut itself down */
 662
 663         if (srv->flags.busy) {
 664             debugs(84, 3, "helperStatefulShutdown: " << hlp->id_name << " #" << srv->index + 1 << " is BUSY.");
 665             continue;
 666         }
 667
 668         if (srv->flags.closing) {
 669             debugs(84, 3, "helperStatefulShutdown: " << hlp->id_name << " #" << srv->index + 1 << " is CLOSING.");
 670             continue;
 671         }
 672
 673         if (srv->flags.reserved) {
 674             if (shutting_down) {
 675                 debugs(84, 3, "helperStatefulShutdown: " << hlp->id_name << " #" << srv->index + 1 << " is RESERVED. Closing anyway.");
 676             } else {
 677                 debugs(84, 3, "helperStatefulShutdown: " << hlp->id_name << " #" << srv->index + 1 << " is RESERVED. Not Shutting Down Yet.");
 678                 continue;
 679             }
 680         }
 681
 682         debugs(84, 3, "helperStatefulShutdown: " << hlp->id_name << " #" << srv->index + 1 << " shutting down.");
 683
 684         /* the rest of the details is dealt with in the helperStatefulServerFree
 685          * close handler
 686          */
 687         srv->closePipesSafely();
 688     }
 689 }
 690
 691 helper::~helper()
 692 {
 693     /* note, don't free id_name, it probably points to static memory */
 694
 695     if (queue.head)
 696         debugs(84, DBG_CRITICAL, "WARNING: freeing " << id_name << " helper with " << stats.queue_size << " requests queued");
 697 }
 698
 699 /* ====================================================================== */
 700 /* LOCAL FUNCTIONS */
 701 /* ====================================================================== */
 702
 703 static void
 704 helperServerFree(helper_server *srv)
 705 {
 706     helper *hlp = srv->parent;
 707     helper_request *r;
 708     int i, concurrency = hlp->childs.concurrency;
 709
 710     if (!concurrency)
 711         concurrency = 1;
 712
 713     if (srv->rbuf) {
 714         memFreeBuf(srv->rbuf_sz, srv->rbuf);
 715         srv->rbuf = NULL;
 716     }
 717
 718     srv->wqueue->clean();
 719     delete srv->wqueue;
 720
 721     if (srv->writebuf) {
 722         srv->writebuf->clean();
 723         delete srv->writebuf;
 724         srv->writebuf = NULL;
 725     }
 726
 727     if (Comm::IsConnOpen(srv->writePipe))
 728         srv->closeWritePipeSafely();
 729
 730     dlinkDelete(&srv->link, &hlp->servers);
 731
 732     assert(hlp->childs.n_running > 0);
 733     -- hlp->childs.n_running;
 734
 735     if (!srv->flags.shutdown) {
 736         assert(hlp->childs.n_active > 0);
 737         -- hlp->childs.n_active;
 738         debugs(84, DBG_CRITICAL, "WARNING: " << hlp->id_name << " #" << srv->index + 1 << " exited");
 739
 740         if (hlp->childs.needNew() > 0) {
 741             debugs(80, DBG_IMPORTANT, "Too few " << hlp->id_name << " processes are running (need " << hlp->childs.needNew() << "/" << hlp->childs.n_max << ")");
 742
 743             if (hlp->childs.n_active < hlp->childs.n_startup && hlp->last_restart > squid_curtime - 30) {
 744                 if (srv->stats.replies < 1)
 745                     fatalf("The %s helpers are crashing too rapidly, need help!\n", hlp->id_name);
 746                 else
 747                     debugs(80, DBG_CRITICAL, "ERROR: The " << hlp->id_name << " helpers are crashing too rapidly, need help!");
 748             }
 749
 750             debugs(80, DBG_IMPORTANT, "Starting new helpers");
 751             helperOpenServers(hlp);
 752         }
 753     }
 754
 755     for (i = 0; i < concurrency; ++i) {
 756         // XXX: re-schedule these on another helper?
 757         if ((r = srv->requests[i])) {
 758             void *cbdata;
 759
 760             if (cbdataReferenceValidDone(r->data, &cbdata)) {
 761                 HelperReply nilReply;
 762                 r->callback(cbdata, nilReply);
 763             }
 764
 765             helperRequestFree(r);
 766
 767             srv->requests[i] = NULL;
 768         }
 769     }
 770     safe_free(srv->requests);
 771
 772     cbdataReferenceDone(srv->parent);
 773     cbdataFree(srv);
 774 }
 775
 776 static void
 777 helperStatefulServerFree(helper_stateful_server *srv)
 778 {
 779     statefulhelper *hlp = srv->parent;
 780     helper_stateful_request *r;
 781
 782     if (srv->rbuf) {
 783         memFreeBuf(srv->rbuf_sz, srv->rbuf);
 784         srv->rbuf = NULL;
 785     }
 786
 787 #if 0
 788     srv->wqueue->clean();
 789
 790     delete srv->wqueue;
 791
 792 #endif
 793
 794     /* TODO: walk the local queue of requests and carry them all out */
 795     if (Comm::IsConnOpen(srv->writePipe))
 796         srv->closeWritePipeSafely();
 797
 798     dlinkDelete(&srv->link, &hlp->servers);
 799
 800     assert(hlp->childs.n_running > 0);
 801     -- hlp->childs.n_running;
 802
 803     if (!srv->flags.shutdown) {
 804         assert( hlp->childs.n_active > 0);
 805         -- hlp->childs.n_active;
 806         debugs(84, DBG_CRITICAL, "WARNING: " << hlp->id_name << " #" << srv->index + 1 << " exited");
 807
 808         if (hlp->childs.needNew() > 0) {
 809             debugs(80, DBG_IMPORTANT, "Too few " << hlp->id_name << " processes are running (need " << hlp->childs.needNew() << "/" << hlp->childs.n_max << ")");
 810
 811             if (hlp->childs.n_active < hlp->childs.n_startup && hlp->last_restart > squid_curtime - 30) {
 812                 if (srv->stats.replies < 1)
 813                     fatalf("The %s helpers are crashing too rapidly, need help!\n", hlp->id_name);
 814                 else
 815                     debugs(80, DBG_CRITICAL, "ERROR: The " << hlp->id_name << " helpers are crashing too rapidly, need help!");
 816             }
 817
 818             debugs(80, DBG_IMPORTANT, "Starting new helpers");
 819             helperStatefulOpenServers(hlp);
 820         }
 821     }
 822
 823     if ((r = srv->request)) {
 824         void *cbdata;
 825
 826         if (cbdataReferenceValidDone(r->data, &cbdata)) {
 827             HelperReply nilReply;
 828             nilReply.whichServer = srv;
 829             r->callback(cbdata, nilReply);
 830         }
 831
 832         helperStatefulRequestFree(r);
 833
 834         srv->request = NULL;
 835     }
 836
 837     if (srv->data != NULL)
 838         hlp->datapool->freeOne(srv->data);
 839
 840     cbdataReferenceDone(srv->parent);
 841
 842     cbdataFree(srv);
 843 }
 844
 845 /// Calls back with a pointer to the buffer with the helper output
 846 static void
 847 helperReturnBuffer(int request_number, helper_server * srv, helper * hlp, char * msg, char * msg_end)
 848 {
 849     helper_request *r = srv->requests[request_number];
 850     if (r) {
 851 // TODO: parse the reply into new helper reply object
 852 // pass that to the callback instead of msg
 853
 854         HLPCB *callback = r->callback;
 855
 856         srv->requests[request_number] = NULL;
 857
 858         r->callback = NULL;
 859
 860         void *cbdata = NULL;
 861         if (cbdataReferenceValidDone(r->data, &cbdata)) {
 862             HelperReply response(msg, (msg_end-msg));
 863             callback(cbdata, response);
 864         }
 865
 866         -- srv->stats.pending;
 867         ++ srv->stats.replies;
 868
 869         ++ hlp->stats.replies;
 870
 871         srv->answer_time = current_time;
 872
 873         srv->dispatch_time = r->dispatch_time;
 874
 875         hlp->stats.avg_svc_time =
 876             Math::intAverage(hlp->stats.avg_svc_time,
 877                              tvSubMsec(r->dispatch_time, current_time),
 878                              hlp->stats.replies, REDIRECT_AV_FACTOR);
 879
 880         helperRequestFree(r);
 881     } else {
 882         debugs(84, DBG_IMPORTANT, "helperHandleRead: unexpected reply on channel " <<
 883                request_number << " from " << hlp->id_name << " #" << srv->index + 1 <<
 884                " '" << srv->rbuf << "'");
 885     }
 886     srv->roffset -= (msg_end - srv->rbuf);
 887     memmove(srv->rbuf, msg_end, srv->roffset + 1);
 888
 889     if (!srv->flags.shutdown) {
 890         helperKickQueue(hlp);
 891     } else if (!srv->flags.closing && !srv->stats.pending) {
 892         srv->flags.closing=1;
 893         srv->writePipe->close();
 894         return;
 895     }
 896 }
 897
 898 static void
 899 helperHandleRead(const Comm::ConnectionPointer &conn, char *buf, size_t len, comm_err_t flag, int xerrno, void *data)
 900 {
 901     char *t = NULL;
 902     helper_server *srv = (helper_server *)data;
 903     helper *hlp = srv->parent;
 904     assert(cbdataReferenceValid(data));
 905
 906     /* Bail out early on COMM_ERR_CLOSING - close handlers will tidy up for us */
 907
 908     if (flag == COMM_ERR_CLOSING) {
 909         return;
 910     }
 911
 912     assert(conn->fd == srv->readPipe->fd);
 913
 914     debugs(84, 5, "helperHandleRead: " << len << " bytes from " << hlp->id_name << " #" << srv->index + 1);
 915
 916     if (flag != COMM_OK || len == 0) {
 917         srv->closePipesSafely();
 918         return;
 919     }
 920
 921     srv->roffset += len;
 922     srv->rbuf[srv->roffset] = '\0';
 923     debugs(84, 9, "helperHandleRead: '" << srv->rbuf << "'");
 924
 925     if (!srv->stats.pending) {
 926         /* someone spoke without being spoken to */
 927         debugs(84, DBG_IMPORTANT, "helperHandleRead: unexpected read from " <<
 928                hlp->id_name << " #" << srv->index + 1 << ", " << (int)len <<
 929                " bytes '" << srv->rbuf << "'");
 930
 931         srv->roffset = 0;
 932         srv->rbuf[0] = '\0';
 933     }
 934
 935     while ((t = strchr(srv->rbuf, hlp->eom))) {
 936         /* end of reply found */
 937         char *msg = srv->rbuf;
 938         int i = 0;
 939         debugs(84, 3, "helperHandleRead: end of reply found");
 940
 941         if (t > srv->rbuf && t[-1] == '\r' && hlp->eom == '\n')
 942             t[-1] = '\0';
 943
 944         *t = '\0';
 945
 946         if (hlp->childs.concurrency) {
 947             i = strtol(msg, &msg, 10);
 948
 949             while (*msg && xisspace(*msg))
 950                 ++msg;
 951         }
 952
 953         helperReturnBuffer(i, srv, hlp, msg, t);
 954         // only skip off the \0 _after_ passing its location to helperReturnBuffer
 955         ++t;
 956     }
 957
 958     if (Comm::IsConnOpen(srv->readPipe)) {
 959         int spaceSize = srv->rbuf_sz - srv->roffset - 1;
 960         assert(spaceSize >= 0);
 961
 962         // grow the input buffer if needed and possible
 963         if (!spaceSize && srv->rbuf_sz + 4096 <= ReadBufMaxSize) {
 964             srv->rbuf = (char *)memReallocBuf(srv->rbuf, srv->rbuf_sz + 4096, &srv->rbuf_sz);
 965             debugs(84, 3, HERE << "Grew read buffer to " << srv->rbuf_sz);
 966             spaceSize = srv->rbuf_sz - srv->roffset - 1;
 967             assert(spaceSize >= 0);
 968         }
 969
 970         // quit reading if there is no space left
 971         if (!spaceSize) {
 972             debugs(84, DBG_IMPORTANT, "ERROR: Disconnecting from a " <<
 973                    "helper that overflowed " << srv->rbuf_sz << "-byte " <<
 974                    "Squid input buffer: " << hlp->id_name << " #" <<
 975                    (srv->index + 1));
 976             srv->closePipesSafely();
 977             return;
 978         }
 979
 980         AsyncCall::Pointer call = commCbCall(5,4, "helperHandleRead",
 981                                              CommIoCbPtrFun(helperHandleRead, srv));
 982         comm_read(srv->readPipe, srv->rbuf + srv->roffset, spaceSize, call);
 983     }
 984 }
 985
 986 static void
 987 helperStatefulHandleRead(const Comm::ConnectionPointer &conn, char *buf, size_t len, comm_err_t flag, int xerrno, void *data)
 988 {
 989     char *t = NULL;
 990     helper_stateful_server *srv = (helper_stateful_server *)data;
 991     helper_stateful_request *r;
 992     statefulhelper *hlp = srv->parent;
 993     assert(cbdataReferenceValid(data));
 994
 995     /* Bail out early on COMM_ERR_CLOSING - close handlers will tidy up for us */
 996
 997     if (flag == COMM_ERR_CLOSING) {
 998         return;
 999     }
1000
1001     assert(conn->fd == srv->readPipe->fd);
1002
1003     debugs(84, 5, "helperStatefulHandleRead: " << len << " bytes from " <<
1004            hlp->id_name << " #" << srv->index + 1);
1005
1006     if (flag != COMM_OK || len == 0) {
1007         srv->closePipesSafely();
1008         return;
1009     }
1010
1011     srv->roffset += len;
1012     srv->rbuf[srv->roffset] = '\0';
1013     r = srv->request;
1014
1015     if (r == NULL) {
1016         /* someone spoke without being spoken to */
1017         debugs(84, DBG_IMPORTANT, "helperStatefulHandleRead: unexpected read from " <<
1018                hlp->id_name << " #" << srv->index + 1 << ", " << (int)len <<
1019                " bytes '" << srv->rbuf << "'");
1020
1021         srv->roffset = 0;
1022     }
1023
1024     if ((t = strchr(srv->rbuf, hlp->eom))) {
1025         /* end of reply found */
1026         int called = 1;
1027         int skip = 1;
1028         debugs(84, 3, "helperStatefulHandleRead: end of reply found");
1029
1030         if (t > srv->rbuf && t[-1] == '\r' && hlp->eom == '\n') {
1031             *t = '\0';
1032             // rewind to the \r octet which is the real terminal now
1033             // and remember that we have to skip forward 2 places now.
1034             skip = 2;
1035             --t;
1036         }
1037
1038         *t = '\0';
1039
1040         if (r && cbdataReferenceValid(r->data)) {
1041             HelperReply res(srv->rbuf, (t - srv->rbuf));
1042             res.whichServer = srv;
1043             r->callback(r->data, res);
1044         } else {
1045             debugs(84, DBG_IMPORTANT, "StatefulHandleRead: no callback data registered");
1046             called = 0;
1047         }
1048         // only skip off the \0's _after_ passing its location in HelperReply above
1049         t += skip;
1050
1051         srv->flags.busy = 0;
1052         srv->roffset = 0;
1053         helperStatefulRequestFree(r);
1054         srv->request = NULL;
1055
1056         -- srv->stats.pending;
1057         ++ srv->stats.replies;
1058
1059         ++ hlp->stats.replies;
1060         srv->answer_time = current_time;
1061         hlp->stats.avg_svc_time =
1062             Math::intAverage(hlp->stats.avg_svc_time,
1063                              tvSubMsec(srv->dispatch_time, current_time),
1064                              hlp->stats.replies, REDIRECT_AV_FACTOR);
1065
1066         if (called)
1067             helperStatefulServerDone(srv);
1068         else
1069             helperStatefulReleaseServer(srv);
1070     }
1071
1072     if (Comm::IsConnOpen(srv->readPipe)) {
1073         int spaceSize = srv->rbuf_sz - srv->roffset - 1;
1074         assert(spaceSize >= 0);
1075
1076         // grow the input buffer if needed and possible
1077         if (!spaceSize && srv->rbuf_sz + 4096 <= ReadBufMaxSize) {
1078             srv->rbuf = (char *)memReallocBuf(srv->rbuf, srv->rbuf_sz + 4096, &srv->rbuf_sz);
1079             debugs(84, 3, HERE << "Grew read buffer to " << srv->rbuf_sz);
1080             spaceSize = srv->rbuf_sz - srv->roffset - 1;
1081             assert(spaceSize >= 0);
1082         }
1083
1084         // quit reading if there is no space left
1085         if (!spaceSize) {
1086             debugs(84, DBG_IMPORTANT, "ERROR: Disconnecting from a " <<
1087                    "helper that overflowed " << srv->rbuf_sz << "-byte " <<
1088                    "Squid input buffer: " << hlp->id_name << " #" <<
1089                    (srv->index + 1));
1090             srv->closePipesSafely();
1091             return;
1092         }
1093
1094         AsyncCall::Pointer call = commCbCall(5,4, "helperStatefulHandleRead",
1095                                              CommIoCbPtrFun(helperStatefulHandleRead, srv));
1096         comm_read(srv->readPipe, srv->rbuf + srv->roffset, spaceSize, call);
1097     }
1098 }
1099
1100 static void
1101 Enqueue(helper * hlp, helper_request * r)
1102 {
1103     dlink_node *link = (dlink_node *)memAllocate(MEM_DLINK_NODE);
1104     dlinkAddTail(r, link, &hlp->queue);
1105     ++ hlp->stats.queue_size;
1106
1107     /* do this first so idle=N has a chance to grow the child pool before it hits critical. */
1108     if (hlp->childs.needNew() > 0) {
1109         debugs(84, DBG_CRITICAL, "Starting new " << hlp->id_name << " helpers...");
1110         helperOpenServers(hlp);
1111         return;
1112     }
1113
1114     if (hlp->stats.queue_size < (int)hlp->childs.n_running)
1115         return;
1116
1117     if (squid_curtime - hlp->last_queue_warn < 600)
1118         return;
1119
1120     if (shutting_down || reconfiguring)
1121         return;
1122
1123     hlp->last_queue_warn = squid_curtime;
1124
1125     debugs(84, DBG_CRITICAL, "WARNING: All " << hlp->childs.n_active << "/" << hlp->childs.n_max << " " << hlp->id_name << " processes are busy.");
1126     debugs(84, DBG_CRITICAL, "WARNING: " << hlp->stats.queue_size << " pending requests queued");
1127     debugs(84, DBG_CRITICAL, "WARNING: Consider increasing the number of " << hlp->id_name << " processes in your config file.");
1128
1129     if (hlp->stats.queue_size > (int)hlp->childs.n_running * 2)
1130         fatalf("Too many queued %s requests", hlp->id_name);
1131 }
1132
1133 static void
1134 StatefulEnqueue(statefulhelper * hlp, helper_stateful_request * r)
1135 {
1136     dlink_node *link = (dlink_node *)memAllocate(MEM_DLINK_NODE);
1137     dlinkAddTail(r, link, &hlp->queue);
1138     ++ hlp->stats.queue_size;
1139
1140     /* do this first so idle=N has a chance to grow the child pool before it hits critical. */
1141     if (hlp->childs.needNew() > 0) {
1142         debugs(84, DBG_CRITICAL, "Starting new " << hlp->id_name << " helpers...");
1143         helperStatefulOpenServers(hlp);
1144         return;
1145     }
1146
1147     if (hlp->stats.queue_size < (int)hlp->childs.n_running)
1148         return;
1149
1150     if (hlp->stats.queue_size > (int)hlp->childs.n_running * 2)
1151         fatalf("Too many queued %s requests", hlp->id_name);
1152
1153     if (squid_curtime - hlp->last_queue_warn < 600)
1154         return;
1155
1156     if (shutting_down || reconfiguring)
1157         return;
1158
1159     hlp->last_queue_warn = squid_curtime;
1160
1161     debugs(84, DBG_CRITICAL, "WARNING: All " << hlp->childs.n_active << "/" << hlp->childs.n_max << " " << hlp->id_name << " processes are busy.");
1162     debugs(84, DBG_CRITICAL, "WARNING: " << hlp->stats.queue_size << " pending requests queued");
1163     debugs(84, DBG_CRITICAL, "WARNING: Consider increasing the number of " << hlp->id_name << " processes in your config file.");
1164 }
1165
1166 static helper_request *
1167 Dequeue(helper * hlp)
1168 {
1169     dlink_node *link;
1170     helper_request *r = NULL;
1171
1172     if ((link = hlp->queue.head)) {
1173         r = (helper_request *)link->data;
1174         dlinkDelete(link, &hlp->queue);
1175         memFree(link, MEM_DLINK_NODE);
1176         -- hlp->stats.queue_size;
1177     }
1178
1179     return r;
1180 }
1181
1182 static helper_stateful_request *
1183 StatefulDequeue(statefulhelper * hlp)
1184 {
1185     dlink_node *link;
1186     helper_stateful_request *r = NULL;
1187
1188     if ((link = hlp->queue.head)) {
1189         r = (helper_stateful_request *)link->data;
1190         dlinkDelete(link, &hlp->queue);
1191         memFree(link, MEM_DLINK_NODE);
1192         -- hlp->stats.queue_size;
1193     }
1194
1195     return r;
1196 }
1197
1198 static helper_server *
1199 GetFirstAvailable(helper * hlp)
1200 {
1201     dlink_node *n;
1202     helper_server *srv;
1203     helper_server *selected = NULL;
1204     debugs(84, 5, "GetFirstAvailable: Running servers " << hlp->childs.n_running);
1205
1206     if (hlp->childs.n_running == 0)
1207         return NULL;
1208
1209     /* Find "least" loaded helper (approx) */
1210     for (n = hlp->servers.head; n != NULL; n = n->next) {
1211         srv = (helper_server *)n->data;
1212
1213         if (selected && selected->stats.pending <= srv->stats.pending)
1214             continue;
1215
1216         if (srv->flags.shutdown)
1217             continue;
1218
1219         if (!srv->stats.pending)
1220             return srv;
1221
1222         if (selected) {
1223             selected = srv;
1224             break;
1225         }
1226
1227         selected = srv;
1228     }
1229
1230     /* Check for overload */
1231     if (!selected) {
1232         debugs(84, 5, "GetFirstAvailable: None available.");
1233         return NULL;
1234     }
1235
1236     if (selected->stats.pending >= (hlp->childs.concurrency ? hlp->childs.concurrency : 1)) {
1237         debugs(84, 3, "GetFirstAvailable: Least-loaded helper is overloaded!");
1238         return NULL;
1239     }
1240
1241     debugs(84, 5, "GetFirstAvailable: returning srv-" << selected->index);
1242     return selected;
1243 }
1244
1245 static helper_stateful_server *
1246 StatefulGetFirstAvailable(statefulhelper * hlp)
1247 {
1248     dlink_node *n;
1249     helper_stateful_server *srv = NULL;
1250     debugs(84, 5, "StatefulGetFirstAvailable: Running servers " << hlp->childs.n_running);
1251
1252     if (hlp->childs.n_running == 0)
1253         return NULL;
1254
1255     for (n = hlp->servers.head; n != NULL; n = n->next) {
1256         srv = (helper_stateful_server *)n->data;
1257
1258         if (srv->flags.busy)
1259             continue;
1260
1261         if (srv->flags.reserved)
1262             continue;
1263
1264         if (srv->flags.shutdown)
1265             continue;
1266
1267         if ((hlp->IsAvailable != NULL) && (srv->data != NULL) && !(hlp->IsAvailable(srv->data)))
1268             continue;
1269
1270         debugs(84, 5, "StatefulGetFirstAvailable: returning srv-" << srv->index);
1271         return srv;
1272     }
1273
1274     debugs(84, 5, "StatefulGetFirstAvailable: None available.");
1275     return NULL;
1276 }
1277
1278 static void
1279 helperDispatchWriteDone(const Comm::ConnectionPointer &conn, char *buf, size_t len, comm_err_t flag, int xerrno, void *data)
1280 {
1281     helper_server *srv = (helper_server *)data;
1282
1283     srv->writebuf->clean();
1284     delete srv->writebuf;
1285     srv->writebuf = NULL;
1286     srv->flags.writing = 0;
1287
1288     if (flag != COMM_OK) {
1289         /* Helper server has crashed */
1290         debugs(84, DBG_CRITICAL, "helperDispatch: Helper " << srv->parent->id_name << " #" << srv->index + 1 << " has crashed");
1291         return;
1292     }
1293
1294     if (!srv->wqueue->isNull()) {
1295         srv->writebuf = srv->wqueue;
1296         srv->wqueue = new MemBuf;
1297         srv->flags.writing = 1;
1298         AsyncCall::Pointer call = commCbCall(5,5, "helperDispatchWriteDone",
1299                                              CommIoCbPtrFun(helperDispatchWriteDone, srv));
1300         Comm::Write(srv->writePipe, srv->writebuf->content(), srv->writebuf->contentSize(), call, NULL);
1301     }
1302 }
1303
1304 static void
1305 helperDispatch(helper_server * srv, helper_request * r)
1306 {
1307     helper *hlp = srv->parent;
1308     helper_request **ptr = NULL;
1309     unsigned int slot;
1310
1311     if (!cbdataReferenceValid(r->data)) {
1312         debugs(84, DBG_IMPORTANT, "helperDispatch: invalid callback data");
1313         helperRequestFree(r);
1314         return;
1315     }
1316
1317     for (slot = 0; slot < (hlp->childs.concurrency ? hlp->childs.concurrency : 1); ++slot) {
1318         if (!srv->requests[slot]) {
1319             ptr = &srv->requests[slot];
1320             break;
1321         }
1322     }
1323
1324     assert(ptr);
1325     *ptr = r;
1326     r->dispatch_time = current_time;
1327
1328     if (srv->wqueue->isNull())
1329         srv->wqueue->init();
1330
1331     if (hlp->childs.concurrency)
1332         srv->wqueue->Printf("%d %s", slot, r->buf);
1333     else
1334         srv->wqueue->append(r->buf, strlen(r->buf));
1335
1336     if (!srv->flags.writing) {
1337         assert(NULL == srv->writebuf);
1338         srv->writebuf = srv->wqueue;
1339         srv->wqueue = new MemBuf;
1340         srv->flags.writing = 1;
1341         AsyncCall::Pointer call = commCbCall(5,5, "helperDispatchWriteDone",
1342                                              CommIoCbPtrFun(helperDispatchWriteDone, srv));
1343         Comm::Write(srv->writePipe, srv->writebuf->content(), srv->writebuf->contentSize(), call, NULL);
1344     }
1345
1346     debugs(84, 5, "helperDispatch: Request sent to " << hlp->id_name << " #" << srv->index + 1 << ", " << strlen(r->buf) << " bytes");
1347
1348     ++ srv->stats.uses;
1349     ++ srv->stats.pending;
1350     ++ hlp->stats.requests;
1351 }
1352
1353 static void
1354 helperStatefulDispatchWriteDone(const Comm::ConnectionPointer &conn, char *buf, size_t len, comm_err_t flag,
1355                                 int xerrno, void *data)
1356 {
1357     /* nothing! */
1358 }
1359
1360 static void
1361 helperStatefulDispatch(helper_stateful_server * srv, helper_stateful_request * r)
1362 {
1363     statefulhelper *hlp = srv->parent;
1364
1365     if (!cbdataReferenceValid(r->data)) {
1366         debugs(84, DBG_IMPORTANT, "helperStatefulDispatch: invalid callback data");
1367         helperStatefulRequestFree(r);
1368         helperStatefulReleaseServer(srv);
1369         return;
1370     }
1371
1372     debugs(84, 9, "helperStatefulDispatch busying helper " << hlp->id_name << " #" << srv->index + 1);
1373
1374     if (r->placeholder == 1) {
1375         /* a callback is needed before this request can _use_ a helper. */
1376         /* we don't care about releasing this helper. The request NEVER
1377          * gets to the helper. So we throw away the return code */
1378         HelperReply nilReply;
1379         nilReply.whichServer = srv;
1380         r->callback(r->data, nilReply);
1381         /* throw away the placeholder */
1382         helperStatefulRequestFree(r);
1383         /* and push the queue. Note that the callback may have submitted a new
1384          * request to the helper which is why we test for the request */
1385
1386         if (srv->request == NULL)
1387             helperStatefulServerDone(srv);
1388
1389         return;
1390     }
1391
1392     srv->flags.busy = 1;
1393     srv->flags.reserved = 1;
1394     srv->request = r;
1395     srv->dispatch_time = current_time;
1396     AsyncCall::Pointer call = commCbCall(5,5, "helperStatefulDispatchWriteDone",
1397                                          CommIoCbPtrFun(helperStatefulDispatchWriteDone, hlp));
1398     Comm::Write(srv->writePipe, r->buf, strlen(r->buf), call, NULL);
1399     debugs(84, 5, "helperStatefulDispatch: Request sent to " <<
1400            hlp->id_name << " #" << srv->index + 1 << ", " <<
1401            (int) strlen(r->buf) << " bytes");
1402
1403     ++ srv->stats.uses;
1404     ++ srv->stats.pending;
1405     ++ hlp->stats.requests;
1406 }
1407
1408 static void
1409 helperKickQueue(helper * hlp)
1410 {
1411     helper_request *r;
1412     helper_server *srv;
1413
1414     while ((srv = GetFirstAvailable(hlp)) && (r = Dequeue(hlp)))
1415         helperDispatch(srv, r);
1416 }
1417
1418 static void
1419 helperStatefulKickQueue(statefulhelper * hlp)
1420 {
1421     helper_stateful_request *r;
1422     helper_stateful_server *srv;
1423
1424     while ((srv = StatefulGetFirstAvailable(hlp)) && (r = StatefulDequeue(hlp)))
1425         helperStatefulDispatch(srv, r);
1426 }
1427
1428 static void
1429 helperStatefulServerDone(helper_stateful_server * srv)
1430 {
1431     if (!srv->flags.shutdown) {
1432         helperStatefulKickQueue(srv->parent);
1433     } else if (!srv->flags.closing && !srv->flags.reserved && !srv->flags.busy) {
1434         srv->closeWritePipeSafely();
1435         return;
1436     }
1437 }
1438
1439 static void
1440 helperRequestFree(helper_request * r)
1441 {
1442     cbdataReferenceDone(r->data);
1443     xfree(r->buf);
1444     delete r;
1445 }
1446
1447 static void
1448 helperStatefulRequestFree(helper_stateful_request * r)
1449 {
1450     if (r) {
1451         cbdataReferenceDone(r->data);
1452         xfree(r->buf);
1453         delete r;
1454     }
1455 }
1456
1457 // TODO: should helper_ and helper_stateful_ have a common parent?
1458 static bool
1459 helperStartStats(StoreEntry *sentry, void *hlp, const char *label)
1460 {
1461     if (!hlp) {
1462         if (label)
1463             storeAppendPrintf(sentry, "%s: unavailable\n", label);
1464         return false;
1465     }
1466
1467     if (label)
1468         storeAppendPrintf(sentry, "%s:\n", label);
1469
1470     return true;
1471 }