server/seshigh.c

   1 /*
   2  * Copyright (C) 1994, Index Data I/S
   3  * All rights reserved.
   4  * Sebastian Hammer, Adam Dickmeiss
   5  *
   6  * $Log: seshigh.c,v $
   7  * Revision 1.22  1995-05-15 11:56:39  quinn
   8  * Asynchronous facilities. Restructuring of seshigh code.
   9  *
  10  * Revision 1.21  1995/05/02  08:53:19  quinn
  11  * Trying in vain to fix comm with ISODE
  12  *
  13  * Revision 1.20  1995/04/20  15:13:00  quinn
  14  * Cosmetic
  15  *
  16  * Revision 1.19  1995/04/18  08:15:34  quinn
  17  * Added dynamic memory allocation on encoding (whew). Code is now somewhat
  18  * neater. We'll make the same change for decoding one day.
  19  *
  20  * Revision 1.18  1995/04/17  11:28:25  quinn
  21  * Smallish
  22  *
  23  * Revision 1.17  1995/04/10  10:23:36  quinn
  24  * Some work to add scan and other things.
  25  *
  26  * Revision 1.16  1995/03/31  09:18:55  quinn
  27  * Added logging.
  28  *
  29  * Revision 1.15  1995/03/30  14:03:23  quinn
  30  * Added RFC1006 as separate library
  31  *
  32  * Revision 1.14  1995/03/30  12:18:17  quinn
  33  * Fixed bug.
  34  *
  35  * Revision 1.13  1995/03/30  09:09:24  quinn
  36  * Added state-handle and some support for asynchronous activities.
  37  *
  38  * Revision 1.12  1995/03/29  15:40:16  quinn
  39  * Ongoing work. Statserv is now dynamic by default
  40  *
  41  * Revision 1.11  1995/03/28  09:16:21  quinn
  42  * Added record packing to the search request
  43  *
  44  * Revision 1.10  1995/03/27  08:34:24  quinn
  45  * Added dynamic server functionality.
  46  * Released bindings to session.c (is now redundant)
  47  *
  48  * Revision 1.9  1995/03/22  15:01:26  quinn
  49  * Adjusting record packing.
  50  *
  51  * Revision 1.8  1995/03/22  10:13:21  quinn
  52  * Working on record packer
  53  *
  54  * Revision 1.7  1995/03/21  15:53:31  quinn
  55  * Little changes.
  56  *
  57  * Revision 1.6  1995/03/21  12:30:09  quinn
  58  * Beginning to add support for record packing.
  59  *
  60  * Revision 1.5  1995/03/17  10:44:13  quinn
  61  * Added catch of null-string in makediagrec
  62  *
  63  * Revision 1.4  1995/03/17  10:18:08  quinn
  64  * Added memory management.
  65  *
  66  * Revision 1.3  1995/03/16  17:42:39  quinn
  67  * Little changes
  68  *
  69  * Revision 1.2  1995/03/16  13:29:01  quinn
  70  * Partitioned server.
  71  *
  72  * Revision 1.1  1995/03/15  16:02:10  quinn
  73  * Modded session.c to seshigh.c
  74  *
  75  */
  76
  77 /*
  78  * Frontend server logic.
  79  *
  80  * This code receives incoming APDUs, and handles client requests by means
  81  * of the backend API.
  82  *
  83  * Some of the code is getting quite involved, compared to simpler servers -
  84  * primarily because it is asynchronous both in the communication with
  85  * the user and the backend. We think the complexity will pay off in
  86  * the form of greater flexibility when more asynchronous facilities
  87  * are implemented.
  88  *
  89  * Memory management has become somewhat involved. In the simple case, where
  90  * only one PDU is pending at a time, it will simply reuse the same memory,
  91  * once it has found its working size. When we enable multiple concurrent
  92  * operations, perhaps even with multiple parallel calls to the backend, it
  93  * will maintain a pool of buffers for encoding and decoding, trying to
  94  * minimize memory allocation/deallocation during normal operation.
  95  *
  96  * TODOs include (and will be done in order of public interest):
  97  *
  98  * Support for EXPLAIN - provide simple meta-database system.
  99  * Support for access control.
 100  * Support for resource control.
 101  * Support for extended services - primarily Item Order.
 102  * Rest of Z39.50-1994
 103  *
 104  */
 105
 106 #include <stdlib.h>
 107 #include <stdio.h>
 108 #include <unistd.h>
 109 #include <assert.h>
 110
 111 #include <dmalloc.h>
 112 #include <comstack.h>
 113 #include <eventl.h>
 114 #include <session.h>
 115 #include <proto.h>
 116 #include <oid.h>
 117 #include <log.h>
 118 #include <statserv.h>
 119
 120 #include <backend.h>
 121
 122 static int process_request(association *assoc);
 123 void backend_response(IOCHAN i, int event);
 124 static int process_response(association *assoc, request *req, Z_APDU *res);
 125 static Z_APDU *process_initRequest(association *assoc, request *reqb);
 126 static Z_APDU *process_searchRequest(association *assoc, request *reqb,
 127     int *fd);
 128 static Z_APDU *response_searchRequest(association *assoc, request *reqb,
 129     bend_searchresult *bsrt, int *fd);
 130 static Z_APDU *process_presentRequest(association *assoc, request *reqb,
 131     int *fd);
 132 static Z_APDU *process_scanRequest(association *assoc, request *reqb, int *fd);
 133
 134 static FILE *apduf = 0; /* for use in static mode */
 135 static statserv_options_block *control_block = 0;
 136
 137 /*
 138  * Create and initialize a new association-handle.
 139  *  channel  : iochannel for the current line.
 140  *  link     : communications channel.
 141  * Returns: 0 or a new association handle.
 142  */
 143 association *create_association(IOCHAN channel, COMSTACK link)
 144 {
 145     association *new;
 146
 147     if (!control_block)
 148         control_block = statserv_getcontrol();
 149     if (!(new = malloc(sizeof(*new))))
 150         return 0;
 151     new->client_chan = channel;
 152     new->client_link = link;
 153     if (!(new->decode = odr_createmem(ODR_DECODE)) ||
 154         !(new->encode = odr_createmem(ODR_ENCODE)))
 155         return 0;
 156     if (*control_block->apdufile)
 157     {
 158         char filename[256];
 159         FILE *f;
 160
 161         if (!(new->print = odr_createmem(ODR_PRINT)))
 162             return 0;
 163         if (*control_block->apdufile != '-')
 164         {
 165             strcpy(filename, control_block->apdufile);
 166             if (!control_block->dynamic)
 167             {
 168                 if (!apduf)
 169                 {
 170                     if (!(apduf = fopen(filename, "w")))
 171                     {
 172                         logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 173                         return 0;
 174                     }
 175                     setvbuf(apduf, 0, _IONBF, 0);
 176                 }
 177                 f = apduf;
 178             }
 179             else
 180             {
 181                 sprintf(filename + strlen(filename), ".%d", getpid());
 182                 if (!(f = fopen(filename, "w")))
 183                 {
 184                     logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 185                     return 0;
 186                 }
 187                 setvbuf(f, 0, _IONBF, 0);
 188             }
 189             odr_setprint(new->print, f);
 190         }
 191     }
 192     else
 193         new->print = 0;
 194     new->input_buffer = 0;
 195     new->input_buffer_len = 0;
 196     new->backend = 0;
 197     request_initq(&new->incoming);
 198     request_initq(&new->outgoing);
 199     if (cs_getproto(link) == CS_Z3950)
 200         new->proto = PROTO_Z3950;
 201     else
 202         new->proto = PROTO_SR;
 203     return new;
 204 }
 205
 206 /*
 207  * Free association and release resources.
 208  */
 209 void destroy_association(association *h)
 210 {
 211     odr_destroy(h->decode);
 212     odr_destroy(h->encode);
 213     if (h->print)
 214         odr_destroy(h->print);
 215     if (h->input_buffer)
 216         free(h->input_buffer);
 217     if (h->backend)
 218         bend_close(h->backend);
 219     while (request_deq(&h->incoming));
 220     while (request_deq(&h->outgoing));
 221     free(h);
 222 }
 223
 224 /*
 225  * This is where PDUs from the client are read and the further
 226  * processing is initiated. Flow of control moves down through the
 227  * various process_* functions below, until the encoded result comes back up
 228  * to the output handler in here.
 229  *
 230  *  h     : the I/O channel that has an outstanding event.
 231  *  event : the current outstanding event.
 232  */
 233 void ir_session(IOCHAN h, int event)
 234 {
 235     int res;
 236     association *assoc = iochan_getdata(h);
 237     COMSTACK conn = assoc->client_link;
 238     request *req;
 239
 240     assert(h && conn && assoc);
 241     if (event & EVENT_INPUT || event & EVENT_WORK) /* input */
 242     {
 243         if (event & EVENT_INPUT)
 244         {
 245             logf(LOG_DEBUG, "ir_session (input)");
 246             assert(assoc && conn);
 247             if ((res = cs_get(conn, &assoc->input_buffer,
 248                 &assoc->input_buffer_len)) <= 0)
 249             {
 250                 logf(LOG_LOG, "Connection closed by client");
 251                 cs_close(conn);
 252                 destroy_association(assoc);
 253                 iochan_destroy(h);
 254                 return;
 255             }
 256             else if (res == 1) /* incomplete read - wait for more  */
 257                 return;
 258             if (cs_more(conn)) /* more stuff - call us again later, please */
 259                 iochan_setevent(h, EVENT_INPUT);
 260
 261             /* we got a complete PDU. Let's decode it */
 262             req = request_get(); /* get a new request structure */
 263             odr_reset(assoc->decode);
 264             odr_setbuf(assoc->decode, assoc->input_buffer,
 265                 assoc->input_apdu_len, 0);
 266             if (!z_APDU(assoc->decode, &req->request, 0))
 267             {
 268                 logf(LOG_WARN, "ODR error: %s",
 269                     odr_errlist[odr_geterror(assoc->decode)]);
 270                 cs_close(conn);
 271                 destroy_association(assoc);
 272                 iochan_destroy(h);
 273                 return;
 274             }
 275             req->request_mem = odr_extract_mem(assoc->decode);
 276             if (assoc->print && !z_APDU(assoc->print, &req->request, 0))
 277             {
 278                 logf(LOG_WARN, "ODR print error: %s",
 279                     odr_errlist[odr_geterror(assoc->print)]);
 280                 odr_reset(assoc->print);
 281             }
 282             request_enq(&assoc->incoming, req);
 283         }
 284
 285         /* can we do something yet? */
 286         req = request_head(&assoc->incoming);
 287         if (req->state == REQUEST_IDLE)
 288             if (process_request(assoc) < 0)
 289             {
 290                 cs_close(conn);
 291                 destroy_association(assoc);
 292                 iochan_destroy(h);
 293             }
 294     }
 295     if (event & EVENT_OUTPUT)
 296     {
 297         request *req = request_head(&assoc->outgoing);
 298
 299         logf(LOG_DEBUG, "ir_session (output)");
 300         req->state = REQUEST_PENDING;
 301         switch (res = cs_put(conn, req->response, req->len_response))
 302         {
 303             case -1:
 304                 logf(LOG_LOG, "Connection closed by client");
 305                 cs_close(conn);
 306                 destroy_association(assoc);
 307                 iochan_destroy(h);
 308                 break;
 309             case 0: /* all sent - release the request structure */
 310                 odr_release_mem(req->request_mem);
 311                 request_deq(&assoc->outgoing);
 312                 request_release(req);
 313                 if (!request_head(&assoc->outgoing))
 314                     iochan_clearflag(h, EVENT_OUTPUT);
 315                 break;
 316             /* value of 1 -- partial send -- is simply ignored */
 317         }
 318     }
 319     if (event & EVENT_EXCEPT)
 320     {
 321         logf(LOG_DEBUG, "ir_session (exception)");
 322         cs_close(conn);
 323         destroy_association(assoc);
 324         iochan_destroy(h);
 325     }
 326 }
 327
 328 /*
 329  * Initiate request processing.
 330  */
 331 static int process_request(association *assoc)
 332 {
 333     request *req = request_head(&assoc->incoming);
 334     int fd = -1;
 335     Z_APDU *res;
 336
 337     logf(LOG_DEBUG, "process_request");
 338     assert(req && req->state == REQUEST_IDLE);
 339     switch (req->request->which)
 340     {
 341         case Z_APDU_initRequest:
 342             res = process_initRequest(assoc, req); break;
 343         case Z_APDU_searchRequest:
 344             res = process_searchRequest(assoc, req, &fd); break;
 345         case Z_APDU_presentRequest:
 346             res = process_presentRequest(assoc, req, &fd); break;
 347         case Z_APDU_scanRequest:
 348             res = process_scanRequest(assoc, req, &fd); break;
 349         default:
 350             logf(LOG_WARN, "Bad APDU");
 351             return -1;
 352     }
 353     if (res)
 354     {
 355         logf(LOG_DEBUG, "  result immediately available");
 356         return process_response(assoc, req, res);
 357     }
 358     else if (fd < 0)
 359     {
 360         logf(LOG_WARN, "   bad result");
 361         return -1;
 362     }
 363     else /* no result yet - one will be provided later */
 364     {
 365         IOCHAN chan;
 366
 367         /* Set up an I/O handler for the fd supplied by the backend */
 368
 369         logf(LOG_DEBUG, "   establishing handler for result");
 370         req->state = REQUEST_PENDING;
 371         if (!(chan = iochan_create(fd, backend_response, EVENT_INPUT)))
 372             abort();
 373         iochan_setdata(chan, assoc);
 374         return 0;
 375     }
 376 }
 377
 378 /*
 379  * Handle message from the backend.
 380  */
 381 void backend_response(IOCHAN i, int event)
 382 {
 383     association *assoc = iochan_getdata(i);
 384     request *req = request_head(&assoc->incoming);
 385     Z_APDU *res;
 386     int fd;
 387
 388     logf(LOG_DEBUG, "backend_response");
 389     assert(assoc && req && req->state != REQUEST_IDLE);
 390     /* determine what it is we're waiting for */
 391     switch (req->request->which)
 392     {
 393         case Z_APDU_searchRequest:
 394             res = response_searchRequest(assoc, req, 0, &fd); break;
 395 #if 0
 396         case Z_APDU_presentRequest:
 397             res = response_presentRequest(assoc, req, 0, &fd); break;
 398         case Z_APDU_scanRequest:
 399             res = response_scanRequest(assoc, req, 0, &fd); break;
 400 #endif
 401         default:
 402             logf(LOG_WARN, "Serious programmer's lapse or bug");
 403             abort();
 404     }
 405     if ((res && process_response(assoc, req, res) < 0) || fd < 0)
 406     {
 407         logf(LOG_LOG, "Fatal error when talking to backend");
 408         cs_close(assoc->client_link);
 409         destroy_association(assoc);
 410         iochan_destroy(assoc->client_chan);
 411         iochan_destroy(i);
 412         return;
 413     }
 414     else if (!res) /* no result yet - try again later */
 415     {
 416         logf(LOG_DEBUG, "   no result yet");
 417         iochan_setfd(i, fd); /* in case fd has changed */
 418     }
 419 }
 420
 421 /*
 422  * Encode response, and transfer the request structure to the outgoing queue.
 423  */
 424 static int process_response(association *assoc, request *req, Z_APDU *res)
 425 {
 426     odr_setbuf(assoc->encode, req->response, req->size_response, 1);
 427     if (!z_APDU(assoc->encode, &res, 0))
 428     {
 429         logf(LOG_WARN, "ODR error when encoding response: %s",
 430             odr_errlist[odr_geterror(assoc->decode)]);
 431         return -1;
 432     }
 433     req->response = odr_getbuf(assoc->encode, &req->len_response,
 434         &req->size_response);
 435     odr_reset(assoc->encode);
 436     /* change this when we make the backend reentrant */
 437     assert(req == request_head(&assoc->incoming));
 438     req->state = REQUEST_IDLE;
 439     request_deq(&assoc->incoming);
 440     request_enq(&assoc->outgoing, req);
 441     /* turn the work over to the ir_session handler */
 442     iochan_setflag(assoc->client_chan, EVENT_OUTPUT);
 443     /* Is there more work to be done? */
 444     if (request_head(&assoc->incoming))
 445         iochan_setevent(assoc->client_chan, EVENT_WORK);
 446     return 0;
 447 }
 448
 449 static Z_APDU *process_initRequest(association *assoc, request *reqb)
 450 {
 451     Z_InitRequest *req = reqb->request->u.initRequest;
 452     static Z_APDU apdu;
 453     static Z_InitResponse resp;
 454     static bool_t result = 1;
 455     static Odr_bitmask options, protocolVersion;
 456     bend_initrequest binitreq;
 457     bend_initresult *binitres;
 458
 459     logf(LOG_LOG, "Got initRequest");
 460     if (req->implementationId)
 461         logf(LOG_LOG, "Id:        %s", req->implementationId);
 462     if (req->implementationName)
 463         logf(LOG_LOG, "Name:      %s", req->implementationName);
 464     if (req->implementationVersion)
 465         logf(LOG_LOG, "Version:   %s", req->implementationVersion);
 466
 467     binitreq.configname = "default-config";
 468     if (!(binitres = bend_init(&binitreq)) || binitres->errcode)
 469     {
 470         logf(LOG_WARN, "Negative response from backend");
 471         return 0;
 472     }
 473
 474     assoc->backend = binitres->handle;
 475     apdu.which = Z_APDU_initResponse;
 476     apdu.u.initResponse = &resp;
 477     resp.referenceId = req->referenceId;
 478     /* let's tell the client what we can do */
 479     ODR_MASK_ZERO(&options);
 480     if (ODR_MASK_GET(req->options, Z_Options_search))
 481         ODR_MASK_SET(&options, Z_Options_search);
 482     if (ODR_MASK_GET(req->options, Z_Options_present))
 483         ODR_MASK_SET(&options, Z_Options_present);
 484 #if 0
 485     if (ODR_MASK_GET(req->options, Z_Options_delSet))
 486         ODR_MASK_SET(&options, Z_Options_delSet);
 487 #endif
 488     if (ODR_MASK_GET(req->options, Z_Options_namedResultSets))
 489         ODR_MASK_SET(&options, Z_Options_namedResultSets);
 490     if (ODR_MASK_GET(req->options, Z_Options_scan))
 491         ODR_MASK_SET(&options, Z_Options_scan);
 492     if (ODR_MASK_GET(req->options, Z_Options_concurrentOperations))
 493         ODR_MASK_SET(&options, Z_Options_concurrentOperations);
 494     resp.options = &options;
 495
 496     ODR_MASK_ZERO(&protocolVersion);
 497     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_1))
 498         ODR_MASK_SET(&protocolVersion, Z_ProtocolVersion_1);
 499     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_2))
 500         ODR_MASK_SET(&protocolVersion, Z_ProtocolVersion_2);
 501     resp.protocolVersion = &protocolVersion;
 502     assoc->maximumRecordSize = *req->maximumRecordSize;
 503     if (assoc->maximumRecordSize > control_block->maxrecordsize)
 504         assoc->maximumRecordSize = control_block->maxrecordsize;
 505     assoc->preferredMessageSize = *req->preferredMessageSize;
 506     if (assoc->preferredMessageSize > assoc->maximumRecordSize)
 507         assoc->preferredMessageSize = assoc->maximumRecordSize;
 508     resp.preferredMessageSize = &assoc->preferredMessageSize;
 509     resp.maximumRecordSize = &assoc->maximumRecordSize;
 510     resp.result = &result;
 511     resp.implementationId = "YAZ";
 512     resp.implementationName = "Index Data/YAZ Generic Frontend Server";
 513     resp.implementationVersion = "$Revision: 1.22 $";
 514     resp.userInformationField = 0;
 515     return &apdu;
 516 }
 517
 518 static Z_Records *diagrec(oid_proto proto, int error, char *addinfo)
 519 {
 520     static Z_Records rec;
 521     oident bib1;
 522     static Z_DiagRec dr;
 523     static int err;
 524
 525     bib1.proto = proto;
 526     bib1.class = CLASS_DIAGSET;
 527     bib1.value = VAL_BIB1;
 528
 529     logf(LOG_DEBUG, "Diagnostic: %d -- %s", error, addinfo ? addinfo :
 530         "NULL");
 531     err = error;
 532     rec.which = Z_Records_NSD;
 533     rec.u.nonSurrogateDiagnostic = &dr;
 534     dr.diagnosticSetId = oid_getoidbyent(&bib1);
 535     dr.condition = &err;
 536     dr.addinfo = addinfo ? addinfo : "";
 537     return &rec;
 538 }
 539
 540 static Z_NamePlusRecord *surrogatediagrec(oid_proto proto, char *dbname,
 541                                             int error, char *addinfo)
 542 {
 543     static Z_NamePlusRecord rec;
 544     static Z_DiagRec dr;
 545     static int err;
 546     oident bib1;
 547
 548     bib1.proto = proto;
 549     bib1.class = CLASS_DIAGSET;
 550     bib1.value = VAL_BIB1;
 551
 552     logf(LOG_DEBUG, "SurrogateDiagnotic: %d -- %s", error, addinfo);
 553     err = error;
 554     rec.databaseName = dbname;
 555     rec.which = Z_NamePlusRecord_surrogateDiagnostic;
 556     rec.u.surrogateDiagnostic = &dr;
 557     dr.diagnosticSetId = oid_getoidbyent(&bib1);
 558     dr.condition = &err;
 559     dr.addinfo = addinfo ? addinfo : "";
 560     return &rec;
 561 }
 562
 563 static Z_DiagRecs *diagrecs(oid_proto proto, int error, char *addinfo)
 564 {
 565     static Z_DiagRecs recs;
 566     static Z_DiagRec *recp[1], rec;
 567     static int err;
 568     oident bib1;
 569
 570     logf(LOG_DEBUG, "DiagRecs: %d -- %s", error, addinfo);
 571     bib1.proto = proto;
 572     bib1.class = CLASS_DIAGSET;
 573     bib1.value = VAL_BIB1;
 574
 575     err = error;
 576     recs.num_diagRecs = 1;
 577     recs.diagRecs = recp;
 578     recp[0] = &rec;
 579     rec.diagnosticSetId = oid_getoidbyent(&bib1);
 580     rec.condition = &err;
 581     rec.addinfo = addinfo ? addinfo : "";
 582     return &recs;
 583 }
 584
 585 #define MAX_RECORDS 256
 586
 587 static Z_Records *pack_records(association *a, char *setname, int start,
 588                                 int *num, Z_ElementSetNames *esn,
 589                                 int *next, int *pres)
 590 {
 591     int recno, total_length = 0, toget = *num;
 592     static Z_Records records;
 593     static Z_NamePlusRecordList reclist;
 594     static Z_NamePlusRecord *list[MAX_RECORDS];
 595     oident recform;
 596     Odr_oid *oid;
 597
 598     records.which = Z_Records_DBOSD;
 599     records.u.databaseOrSurDiagnostics = &reclist;
 600     reclist.num_records = 0;
 601     reclist.records = list;
 602     *pres = Z_PRES_SUCCESS;
 603     *num = 0;
 604     *next = 0;
 605
 606     recform.proto = a->proto;
 607     recform.class = CLASS_RECSYN;
 608     recform.value = VAL_USMARC;
 609     if (!(oid = odr_oiddup(a->encode, oid_getoidbyent(&recform))))
 610         return 0;
 611
 612     logf(LOG_DEBUG, "Request to pack %d+%d", start, toget);
 613     logf(LOG_DEBUG, "pms=%d, mrs=%d", a->preferredMessageSize,
 614         a->maximumRecordSize);
 615     for (recno = start; reclist.num_records < toget; recno++)
 616     {
 617         bend_fetchrequest freq;
 618         bend_fetchresult *fres;
 619         Z_NamePlusRecord *thisrec;
 620         Z_DatabaseRecord *thisext;
 621
 622         if (reclist.num_records == MAX_RECORDS - 1)
 623         {
 624             *pres = Z_PRES_PARTIAL_2;
 625             break;
 626         }
 627         freq.setname = setname;
 628         freq.number = recno;
 629         if (!(fres = bend_fetch(a->backend, &freq, 0)))
 630         {
 631             *pres = Z_PRES_FAILURE;
 632             return diagrec(a->proto, 2, "Backend interface problem");
 633         }
 634         /* backend should be able to signal whether error is system-wide
 635            or only pertaining to current record */
 636         if (fres->errcode)
 637         {
 638             *pres = Z_PRES_FAILURE;
 639             return diagrec(a->proto, fres->errcode, fres->errstring);
 640         }
 641         logf(LOG_DEBUG, "  fetched record, len=%d, total=%d",
 642             fres->len, total_length);
 643         if (fres->len + total_length > a->preferredMessageSize)
 644         {
 645             /* record is small enough, really */
 646             if (fres->len <= a->preferredMessageSize)
 647             {
 648                 logf(LOG_DEBUG, "  Dropped last normal-sized record");
 649                 *pres = Z_PRES_PARTIAL_2;
 650                 break;
 651             }
 652             /* record can only be fetched by itself */
 653             if (fres->len < a->maximumRecordSize)
 654             {
 655                 logf(LOG_DEBUG, "  Record > prefmsgsz");
 656                 if (toget > 1)
 657                 {
 658                     logf(LOG_DEBUG, "  Dropped it");
 659                     reclist.records[reclist.num_records] =
 660                          surrogatediagrec(a->proto, fres->basename, 16, 0);
 661                     reclist.num_records++;
 662                     *pres = Z_PRES_PARTIAL_2;
 663                     break;
 664                 }
 665             }
 666             else /* too big entirely */
 667             {
 668                 logf(LOG_DEBUG, "Record > maxrcdsz");
 669                 reclist.records[reclist.num_records] =
 670                     surrogatediagrec(a->proto, fres->basename, 17, 0);
 671                 reclist.num_records++;
 672                 *pres = Z_PRES_PARTIAL_2;
 673                 break;
 674             }
 675         }
 676         if (!(thisrec = odr_malloc(a->encode, sizeof(*thisrec))))
 677             return 0;
 678         if (!(thisrec->databaseName = odr_malloc(a->encode,
 679             strlen(fres->basename) + 1)))
 680             return 0;
 681         strcpy(thisrec->databaseName, fres->basename);
 682         thisrec->which = Z_NamePlusRecord_databaseRecord;
 683         if (!(thisrec->u.databaseRecord = thisext = odr_malloc(a->encode,
 684             sizeof(Z_DatabaseRecord))))
 685             return 0;
 686         thisext->direct_reference = oid; /* should be OID for current MARC */
 687         thisext->indirect_reference = 0;
 688         thisext->descriptor = 0;
 689         thisext->which = ODR_EXTERNAL_octet;
 690         if (!(thisext->u.octet_aligned = odr_malloc(a->encode,
 691             sizeof(Odr_oct))))
 692             return 0;
 693         if (!(thisext->u.octet_aligned->buf = odr_malloc(a->encode, fres->len)))
 694             return 0;
 695         memcpy(thisext->u.octet_aligned->buf, fres->record, fres->len);
 696         thisext->u.octet_aligned->len = thisext->u.octet_aligned->size =
 697             fres->len;
 698         reclist.records[reclist.num_records] = thisrec;
 699         reclist.num_records++;
 700         total_length += fres->len;
 701         (*num)++;
 702         *next = fres->last_in_set ? 0 : recno + 1;
 703     }
 704     return &records;
 705 }
 706
 707 static Z_APDU *process_searchRequest(association *assoc, request *reqb,
 708     int *fd)
 709 {
 710     Z_SearchRequest *req = reqb->request->u.searchRequest;
 711     bend_searchrequest bsrq;
 712     bend_searchresult *bsrt;
 713
 714     logf(LOG_LOG, "Got SearchRequest.");
 715
 716     bsrq.setname = req->resultSetName;
 717     bsrq.replace_set = *req->replaceIndicator;
 718     bsrq.num_bases = req->num_databaseNames;
 719     bsrq.basenames = req->databaseNames;
 720     bsrq.query = req->query;
 721
 722     if (!(bsrt = bend_search(assoc->backend, &bsrq, fd)))
 723         return 0;
 724     return response_searchRequest(assoc, reqb, bsrt, fd);
 725 }
 726
 727 bend_searchresult *bend_searchresponse(void *handle) {return 0;}
 728
 729 /*
 730  * Prepare a searchresponse based on the backend results. We probably want
 731  * to look at making the fetching of records nonblocking as well, but
 732  * so far, we'll keep things simple.
 733  * If bsrt is null, that means we're called in response to a communications
 734  * event, and we'll have to get the response for ourselves.
 735  */
 736 static Z_APDU *response_searchRequest(association *assoc, request *reqb,
 737     bend_searchresult *bsrt, int *fd)
 738 {
 739     Z_SearchRequest *req = reqb->request->u.searchRequest;
 740     static Z_APDU apdu;
 741     static Z_SearchResponse resp;
 742     static int nulint = 0;
 743     static bool_t sr = 1;
 744     static int next = 0;
 745     static int none = Z_RES_NONE;
 746
 747     apdu.which = Z_APDU_searchResponse;
 748     apdu.u.searchResponse = &resp;
 749     resp.referenceId = req->referenceId;
 750     *fd = -1;
 751     if (!bsrt && !(bsrt = bend_searchresponse(assoc->backend)))
 752     {
 753         logf(LOG_FATAL, "Bad result from backend");
 754         return 0;
 755     }
 756     else if (bsrt->errcode)
 757     {
 758         resp.records = diagrec(assoc->proto, bsrt->errcode,
 759             bsrt->errstring);
 760         resp.resultCount = &nulint;
 761         resp.numberOfRecordsReturned = &nulint;
 762         resp.nextResultSetPosition = &nulint;
 763         resp.searchStatus = &nulint;
 764         resp.resultSetStatus = &none;
 765         resp.presentStatus = 0;
 766     }
 767     else
 768     {
 769         int toget;
 770         Z_ElementSetNames *setnames;
 771         int presst = 0;
 772
 773         resp.records = 0;
 774         resp.resultCount = &bsrt->hits;
 775
 776         /* how many records does the user agent want, then? */
 777         if (bsrt->hits <= *req->smallSetUpperBound)
 778         {
 779             toget = bsrt->hits;
 780             setnames = req->smallSetElementSetNames;
 781         }
 782         else if (bsrt->hits < *req->largeSetLowerBound)
 783         {
 784             toget = *req->mediumSetPresentNumber;
 785             if (toget > bsrt->hits)
 786                 toget = bsrt->hits;
 787             setnames = req->mediumSetElementSetNames;
 788         }
 789         else
 790             toget = 0;
 791
 792         if (toget && !resp.records)
 793         {
 794             resp.records = pack_records(assoc, req->resultSetName, 1,
 795                 &toget, setnames, &next, &presst);
 796             if (!resp.records)
 797                 return 0;
 798             resp.numberOfRecordsReturned = &toget;
 799             resp.nextResultSetPosition = &next;
 800             resp.searchStatus = &sr;
 801             resp.resultSetStatus = 0;
 802             resp.presentStatus = &presst;
 803         }
 804         else
 805         {
 806             resp.numberOfRecordsReturned = &nulint;
 807             resp.nextResultSetPosition = &next;
 808             resp.searchStatus = &sr;
 809             resp.resultSetStatus = 0;
 810             resp.presentStatus = 0;
 811         }
 812     }
 813     return &apdu;
 814 }
 815
 816 /*
 817  * Maybe we got a little over-friendly when we designed bend_fetch to
 818  * get only one record at a time. Some backends can optimise multiple-record
 819  * fetches, and at any rate, there is some overhead involved in
 820  * all that selecting and hopping around. Problem is, of course, that the
 821  * frontend can't know ahead of time how many records it'll need to
 822  * fill the negotiated PDU size. Annoying. Segmentation or not, Z/SR
 823  * is downright lousy as a bulk data transfer protocol.
 824  *
 825  * To start with, we'll do the fetching of records from the backend
 826  * in one operation: To save some trips in and out of the event-handler,
 827  * and to simplify the interface to pack_records. At any rate, asynch
 828  * operation is more fun in operations that have an unpredictable execution
 829  * speed - which is normally more true for search than for present.
 830  */
 831 static Z_APDU *process_presentRequest(association *assoc, request *reqb,
 832     int *fd)
 833 {
 834     Z_PresentRequest *req = reqb->request->u.presentRequest;
 835     static Z_APDU apdu;
 836     static Z_PresentResponse resp;
 837     static int presst, next, num;
 838
 839     logf(LOG_LOG, "Got PresentRequest.");
 840     apdu.which = Z_APDU_presentResponse;
 841     apdu.u.presentResponse = &resp;
 842     resp.referenceId = req->referenceId;
 843
 844     num = *req->numberOfRecordsRequested;
 845     resp.records = pack_records(assoc, req->resultSetId,
 846         *req->resultSetStartPoint, &num, req->elementSetNames, &next, &presst);
 847     if (!resp.records)
 848         return 0;
 849     resp.numberOfRecordsReturned = &num;
 850     resp.presentStatus = &presst;
 851     resp.nextResultSetPosition = &next;
 852
 853     return &apdu;
 854 }
 855
 856 /*
 857  * Scan was implemented rather in a hurry, and with support for only the basic
 858  * elements of the service in the backend API. Suggestions are welcome.
 859  */
 860 static Z_APDU *process_scanRequest(association *assoc, request *reqb, int *fd)
 861 {
 862     Z_ScanRequest *req = reqb->request->u.scanRequest;
 863     static Z_APDU apdu;
 864     static Z_ScanResponse res;
 865     static int scanStatus = Z_Scan_failure;
 866     static int numberOfEntriesReturned = 0;
 867     oident *attent;
 868     static Z_ListEntries ents;
 869 #define SCAN_MAX_ENTRIES 200
 870     static Z_Entry *tab[SCAN_MAX_ENTRIES];
 871     bend_scanrequest srq;
 872     bend_scanresult *srs;
 873
 874     apdu.which = Z_APDU_scanResponse;
 875     apdu.u.scanResponse = &res;
 876     res.referenceId = req->referenceId;
 877     res.stepSize = 0;
 878     res.scanStatus = &scanStatus;
 879     res.numberOfEntriesReturned = &numberOfEntriesReturned;
 880     res.positionOfTerm = 0;
 881     res.entries = &ents;
 882     ents.which = Z_ListEntries_nonSurrogateDiagnostics;
 883     res.attributeSet = 0;
 884
 885     if (req->attributeSet && (!(attent = oid_getentbyoid(req->attributeSet)) ||
 886         attent->class != CLASS_ATTSET || attent->value != VAL_BIB1))
 887         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 121, 0);
 888     else if (req->stepSize && *req->stepSize > 0)
 889         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 205, 0);
 890     else
 891     {
 892         srq.num_bases = req->num_databaseNames;
 893         srq.basenames = req->databaseNames;
 894         srq.num_entries = *req->numberOfTermsRequested;
 895         srq.term = req->termListAndStartPoint;
 896         srq.term_position = req->preferredPositionInResponse ?
 897             *req->preferredPositionInResponse : 1;
 898         if (!(srs = bend_scan(assoc->backend, &srq, 0)))
 899             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 2, 0);
 900         else if (srs->errcode)
 901             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto,
 902                 srs->errcode, srs->errstring);
 903         else
 904         {
 905             int i;
 906             static Z_Entries list;
 907
 908             if (srs->status == BEND_SCAN_PARTIAL)
 909                 scanStatus = Z_Scan_partial_5;
 910             else
 911                 scanStatus = Z_Scan_success;
 912             ents.which = Z_ListEntries_entries;
 913             ents.u.entries = &list;
 914             list.entries = tab;
 915             for (i = 0; i < srs->num_entries; i++)
 916             {
 917                 Z_Entry *e;
 918                 Z_TermInfo *t;
 919                 Odr_oct *o;
 920
 921                 if (i >= SCAN_MAX_ENTRIES)
 922                 {
 923                     scanStatus = Z_Scan_partial_4;
 924                     break;
 925                 }
 926                 list.entries[i] = e = odr_malloc(assoc->encode, sizeof(*e));
 927                 e->which = Z_Entry_termInfo;
 928                 e->u.termInfo = t = odr_malloc(assoc->encode, sizeof(*t));
 929                 t->suggestedAttributes = 0;
 930                 t->alternativeTerm = 0;
 931                 t->byAttributes = 0;
 932                 t->globalOccurrences = &srs->entries[i].occurrences;
 933                 t->term = odr_malloc(assoc->encode, sizeof(*t->term));
 934                 t->term->which = Z_Term_general;
 935                 t->term->u.general = o = odr_malloc(assoc->encode,
 936                     sizeof(Odr_oct));
 937                 o->buf = odr_malloc(assoc->encode, o->len = o->size =
 938                     strlen(srs->entries[i].term));
 939                 memcpy(o->buf, srs->entries[i].term, o->len);
 940             }
 941             list.num_entries = i;
 942             res.numberOfEntriesReturned = &list.num_entries;
 943             res.positionOfTerm = &srs->term_position;
 944         }
 945     }
 946
 947     return &apdu;
 948 }