server/seshigh.c

   1 /*
   2  * Copyright (c) 1995, Index Data
   3  * See the file LICENSE for details.
   4  * Sebastian Hammer, Adam Dickmeiss
   5  *
   6  * $Log: seshigh.c,v $
   7  * Revision 1.28  1995-06-01 11:21:01  quinn
   8  * Attempting to fix a bug in pack-records. replaced break with continue
   9  * for large records, according to standard.
  10  *
  11  * Revision 1.27  1995/05/29  08:12:06  quinn
  12  * Moved oid to util
  13  *
  14  * Revision 1.26  1995/05/18  13:02:12  quinn
  15  * Smallish.
  16  *
  17  * Revision 1.25  1995/05/17  08:42:26  quinn
  18  * Transfer auth info to backend. Allow backend to reject init gracefully.
  19  *
  20  * Revision 1.24  1995/05/16  08:51:04  quinn
  21  * License, documentation, and memory fixes
  22  *
  23  * Revision 1.23  1995/05/15  13:25:10  quinn
  24  * Fixed memory bug.
  25  *
  26  * Revision 1.22  1995/05/15  11:56:39  quinn
  27  * Asynchronous facilities. Restructuring of seshigh code.
  28  *
  29  * Revision 1.21  1995/05/02  08:53:19  quinn
  30  * Trying in vain to fix comm with ISODE
  31  *
  32  * Revision 1.20  1995/04/20  15:13:00  quinn
  33  * Cosmetic
  34  *
  35  * Revision 1.19  1995/04/18  08:15:34  quinn
  36  * Added dynamic memory allocation on encoding (whew). Code is now somewhat
  37  * neater. We'll make the same change for decoding one day.
  38  *
  39  * Revision 1.18  1995/04/17  11:28:25  quinn
  40  * Smallish
  41  *
  42  * Revision 1.17  1995/04/10  10:23:36  quinn
  43  * Some work to add scan and other things.
  44  *
  45  * Revision 1.16  1995/03/31  09:18:55  quinn
  46  * Added logging.
  47  *
  48  * Revision 1.15  1995/03/30  14:03:23  quinn
  49  * Added RFC1006 as separate library
  50  *
  51  * Revision 1.14  1995/03/30  12:18:17  quinn
  52  * Fixed bug.
  53  *
  54  * Revision 1.13  1995/03/30  09:09:24  quinn
  55  * Added state-handle and some support for asynchronous activities.
  56  *
  57  * Revision 1.12  1995/03/29  15:40:16  quinn
  58  * Ongoing work. Statserv is now dynamic by default
  59  *
  60  * Revision 1.11  1995/03/28  09:16:21  quinn
  61  * Added record packing to the search request
  62  *
  63  * Revision 1.10  1995/03/27  08:34:24  quinn
  64  * Added dynamic server functionality.
  65  * Released bindings to session.c (is now redundant)
  66  *
  67  * Revision 1.9  1995/03/22  15:01:26  quinn
  68  * Adjusting record packing.
  69  *
  70  * Revision 1.8  1995/03/22  10:13:21  quinn
  71  * Working on record packer
  72  *
  73  * Revision 1.7  1995/03/21  15:53:31  quinn
  74  * Little changes.
  75  *
  76  * Revision 1.6  1995/03/21  12:30:09  quinn
  77  * Beginning to add support for record packing.
  78  *
  79  * Revision 1.5  1995/03/17  10:44:13  quinn
  80  * Added catch of null-string in makediagrec
  81  *
  82  * Revision 1.4  1995/03/17  10:18:08  quinn
  83  * Added memory management.
  84  *
  85  * Revision 1.3  1995/03/16  17:42:39  quinn
  86  * Little changes
  87  *
  88  * Revision 1.2  1995/03/16  13:29:01  quinn
  89  * Partitioned server.
  90  *
  91  * Revision 1.1  1995/03/15  16:02:10  quinn
  92  * Modded session.c to seshigh.c
  93  *
  94  */
  95
  96 /*
  97  * Frontend server logic.
  98  *
  99  * This code receives incoming APDUs, and handles client requests by means
 100  * of the backend API.
 101  *
 102  * Some of the code is getting quite involved, compared to simpler servers -
 103  * primarily because it is asynchronous both in the communication with
 104  * the user and the backend. We think the complexity will pay off in
 105  * the form of greater flexibility when more asynchronous facilities
 106  * are implemented.
 107  *
 108  * Memory management has become somewhat involved. In the simple case, where
 109  * only one PDU is pending at a time, it will simply reuse the same memory,
 110  * once it has found its working size. When we enable multiple concurrent
 111  * operations, perhaps even with multiple parallel calls to the backend, it
 112  * will maintain a pool of buffers for encoding and decoding, trying to
 113  * minimize memory allocation/deallocation during normal operation.
 114  *
 115  * TODOs include (and will be done in order of public interest):
 116  *
 117  * Support for EXPLAIN - provide simple meta-database system.
 118  * Support for access control.
 119  * Support for resource control.
 120  * Support for extended services - primarily Item Order.
 121  * Rest of Z39.50-1994
 122  *
 123  */
 124
 125 #include <stdlib.h>
 126 #include <stdio.h>
 127 #include <unistd.h>
 128 #include <assert.h>
 129
 130 #include <dmalloc.h>
 131 #include <comstack.h>
 132 #include <eventl.h>
 133 #include <session.h>
 134 #include <proto.h>
 135 #include <oid.h>
 136 #include <log.h>
 137 #include <statserv.h>
 138 #include "../version.h"
 139
 140 #include <backend.h>
 141
 142 static int process_request(association *assoc);
 143 void backend_response(IOCHAN i, int event);
 144 static int process_response(association *assoc, request *req, Z_APDU *res);
 145 static Z_APDU *process_initRequest(association *assoc, request *reqb);
 146 static Z_APDU *process_searchRequest(association *assoc, request *reqb,
 147     int *fd);
 148 static Z_APDU *response_searchRequest(association *assoc, request *reqb,
 149     bend_searchresult *bsrt, int *fd);
 150 static Z_APDU *process_presentRequest(association *assoc, request *reqb,
 151     int *fd);
 152 static Z_APDU *process_scanRequest(association *assoc, request *reqb, int *fd);
 153
 154 static FILE *apduf = 0; /* for use in static mode */
 155 static statserv_options_block *control_block = 0;
 156
 157 /*
 158  * Create and initialize a new association-handle.
 159  *  channel  : iochannel for the current line.
 160  *  link     : communications channel.
 161  * Returns: 0 or a new association handle.
 162  */
 163 association *create_association(IOCHAN channel, COMSTACK link)
 164 {
 165     association *new;
 166
 167     if (!control_block)
 168         control_block = statserv_getcontrol();
 169     if (!(new = malloc(sizeof(*new))))
 170         return 0;
 171     new->client_chan = channel;
 172     new->client_link = link;
 173     if (!(new->decode = odr_createmem(ODR_DECODE)) ||
 174         !(new->encode = odr_createmem(ODR_ENCODE)))
 175         return 0;
 176     if (*control_block->apdufile)
 177     {
 178         char filename[256];
 179         FILE *f;
 180
 181         strcpy(filename, control_block->apdufile);
 182         if (!(new->print = odr_createmem(ODR_PRINT)))
 183             return 0;
 184         if (*control_block->apdufile != '-')
 185         {
 186             strcpy(filename, control_block->apdufile);
 187             if (!control_block->dynamic)
 188             {
 189                 if (!apduf)
 190                 {
 191                     if (!(apduf = fopen(filename, "w")))
 192                     {
 193                         logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 194                         return 0;
 195                     }
 196                     setvbuf(apduf, 0, _IONBF, 0);
 197                 }
 198                 f = apduf;
 199             }
 200             else
 201             {
 202                 sprintf(filename + strlen(filename), ".%d", getpid());
 203                 if (!(f = fopen(filename, "w")))
 204                 {
 205                     logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 206                     return 0;
 207                 }
 208                 setvbuf(f, 0, _IONBF, 0);
 209             }
 210             odr_setprint(new->print, f);
 211         }
 212     }
 213     else
 214         new->print = 0;
 215     new->input_buffer = 0;
 216     new->input_buffer_len = 0;
 217     new->backend = 0;
 218     new->rejected = 0;
 219     request_initq(&new->incoming);
 220     request_initq(&new->outgoing);
 221     new->proto = cs_getproto(link);
 222     return new;
 223 }
 224
 225 /*
 226  * Free association and release resources.
 227  */
 228 void destroy_association(association *h)
 229 {
 230     odr_destroy(h->decode);
 231     odr_destroy(h->encode);
 232     if (h->print)
 233         odr_destroy(h->print);
 234     if (h->input_buffer)
 235         free(h->input_buffer);
 236     if (h->backend)
 237         bend_close(h->backend);
 238     while (request_deq(&h->incoming));
 239     while (request_deq(&h->outgoing));
 240     free(h);
 241 }
 242
 243 /*
 244  * This is where PDUs from the client are read and the further
 245  * processing is initiated. Flow of control moves down through the
 246  * various process_* functions below, until the encoded result comes back up
 247  * to the output handler in here.
 248  *
 249  *  h     : the I/O channel that has an outstanding event.
 250  *  event : the current outstanding event.
 251  */
 252 void ir_session(IOCHAN h, int event)
 253 {
 254     int res;
 255     association *assoc = iochan_getdata(h);
 256     COMSTACK conn = assoc->client_link;
 257     request *req;
 258
 259     assert(h && conn && assoc);
 260     if (event & EVENT_INPUT || event & EVENT_WORK) /* input */
 261     {
 262         if (event & EVENT_INPUT)
 263         {
 264             logf(LOG_DEBUG, "ir_session (input)");
 265             assert(assoc && conn);
 266             if (assoc->rejected)
 267             {
 268                 logf(LOG_LOG, "Closed connection after reject");
 269                 cs_close(conn);
 270                 destroy_association(assoc);
 271                 iochan_destroy(h);
 272                 return;
 273             }
 274             if ((res = cs_get(conn, &assoc->input_buffer,
 275                 &assoc->input_buffer_len)) <= 0)
 276             {
 277                 logf(LOG_LOG, "Connection closed by client");
 278                 cs_close(conn);
 279                 destroy_association(assoc);
 280                 iochan_destroy(h);
 281                 return;
 282             }
 283             else if (res == 1) /* incomplete read - wait for more  */
 284                 return;
 285             if (cs_more(conn)) /* more stuff - call us again later, please */
 286                 iochan_setevent(h, EVENT_INPUT);
 287
 288             /* we got a complete PDU. Let's decode it */
 289             req = request_get(); /* get a new request structure */
 290             odr_reset(assoc->decode);
 291             odr_setbuf(assoc->decode, assoc->input_buffer, res, 0);
 292             if (!z_APDU(assoc->decode, &req->request, 0))
 293             {
 294                 logf(LOG_WARN, "ODR error: %s",
 295                     odr_errlist[odr_geterror(assoc->decode)]);
 296                 cs_close(conn);
 297                 destroy_association(assoc);
 298                 iochan_destroy(h);
 299                 return;
 300             }
 301             req->request_mem = odr_extract_mem(assoc->decode);
 302             if (assoc->print && !z_APDU(assoc->print, &req->request, 0))
 303             {
 304                 logf(LOG_WARN, "ODR print error: %s",
 305                     odr_errlist[odr_geterror(assoc->print)]);
 306                 odr_reset(assoc->print);
 307             }
 308             request_enq(&assoc->incoming, req);
 309         }
 310
 311         /* can we do something yet? */
 312         req = request_head(&assoc->incoming);
 313         if (req->state == REQUEST_IDLE)
 314             if (process_request(assoc) < 0)
 315             {
 316                 cs_close(conn);
 317                 destroy_association(assoc);
 318                 iochan_destroy(h);
 319             }
 320     }
 321     if (event & EVENT_OUTPUT)
 322     {
 323         request *req = request_head(&assoc->outgoing);
 324
 325         logf(LOG_DEBUG, "ir_session (output)");
 326         req->state = REQUEST_PENDING;
 327         switch (res = cs_put(conn, req->response, req->len_response))
 328         {
 329             case -1:
 330                 logf(LOG_LOG, "Connection closed by client");
 331                 cs_close(conn);
 332                 destroy_association(assoc);
 333                 iochan_destroy(h);
 334                 break;
 335             case 0: /* all sent - release the request structure */
 336                 odr_release_mem(req->request_mem);
 337                 request_deq(&assoc->outgoing);
 338                 request_release(req);
 339                 if (!request_head(&assoc->outgoing))
 340                     iochan_clearflag(h, EVENT_OUTPUT);
 341                 break;
 342             /* value of 1 -- partial send -- is simply ignored */
 343         }
 344     }
 345     if (event & EVENT_EXCEPT)
 346     {
 347         logf(LOG_DEBUG, "ir_session (exception)");
 348         cs_close(conn);
 349         destroy_association(assoc);
 350         iochan_destroy(h);
 351     }
 352 }
 353
 354 /*
 355  * Initiate request processing.
 356  */
 357 static int process_request(association *assoc)
 358 {
 359     request *req = request_head(&assoc->incoming);
 360     int fd = -1;
 361     Z_APDU *res;
 362
 363     logf(LOG_DEBUG, "process_request");
 364     assert(req && req->state == REQUEST_IDLE);
 365     switch (req->request->which)
 366     {
 367         case Z_APDU_initRequest:
 368             res = process_initRequest(assoc, req); break;
 369         case Z_APDU_searchRequest:
 370             res = process_searchRequest(assoc, req, &fd); break;
 371         case Z_APDU_presentRequest:
 372             res = process_presentRequest(assoc, req, &fd); break;
 373         case Z_APDU_scanRequest:
 374             res = process_scanRequest(assoc, req, &fd); break;
 375         default:
 376             logf(LOG_WARN, "Bad APDU");
 377             return -1;
 378     }
 379     if (res)
 380     {
 381         logf(LOG_DEBUG, "  result immediately available");
 382         return process_response(assoc, req, res);
 383     }
 384     else if (fd < 0)
 385     {
 386         logf(LOG_WARN, "   bad result");
 387         return -1;
 388     }
 389     else /* no result yet - one will be provided later */
 390     {
 391         IOCHAN chan;
 392
 393         /* Set up an I/O handler for the fd supplied by the backend */
 394
 395         logf(LOG_DEBUG, "   establishing handler for result");
 396         req->state = REQUEST_PENDING;
 397         if (!(chan = iochan_create(fd, backend_response, EVENT_INPUT)))
 398             abort();
 399         iochan_setdata(chan, assoc);
 400         return 0;
 401     }
 402 }
 403
 404 /*
 405  * Handle message from the backend.
 406  */
 407 void backend_response(IOCHAN i, int event)
 408 {
 409     association *assoc = iochan_getdata(i);
 410     request *req = request_head(&assoc->incoming);
 411     Z_APDU *res;
 412     int fd;
 413
 414     logf(LOG_DEBUG, "backend_response");
 415     assert(assoc && req && req->state != REQUEST_IDLE);
 416     /* determine what it is we're waiting for */
 417     switch (req->request->which)
 418     {
 419         case Z_APDU_searchRequest:
 420             res = response_searchRequest(assoc, req, 0, &fd); break;
 421 #if 0
 422         case Z_APDU_presentRequest:
 423             res = response_presentRequest(assoc, req, 0, &fd); break;
 424         case Z_APDU_scanRequest:
 425             res = response_scanRequest(assoc, req, 0, &fd); break;
 426 #endif
 427         default:
 428             logf(LOG_WARN, "Serious programmer's lapse or bug");
 429             abort();
 430     }
 431     if ((res && process_response(assoc, req, res) < 0) || fd < 0)
 432     {
 433         logf(LOG_LOG, "Fatal error when talking to backend");
 434         cs_close(assoc->client_link);
 435         destroy_association(assoc);
 436         iochan_destroy(assoc->client_chan);
 437         iochan_destroy(i);
 438         return;
 439     }
 440     else if (!res) /* no result yet - try again later */
 441     {
 442         logf(LOG_DEBUG, "   no result yet");
 443         iochan_setfd(i, fd); /* in case fd has changed */
 444     }
 445 }
 446
 447 /*
 448  * Encode response, and transfer the request structure to the outgoing queue.
 449  */
 450 static int process_response(association *assoc, request *req, Z_APDU *res)
 451 {
 452     odr_setbuf(assoc->encode, req->response, req->size_response, 1);
 453     if (!z_APDU(assoc->encode, &res, 0))
 454     {
 455         logf(LOG_WARN, "ODR error when encoding response: %s",
 456             odr_errlist[odr_geterror(assoc->decode)]);
 457         return -1;
 458     }
 459     req->response = odr_getbuf(assoc->encode, &req->len_response,
 460         &req->size_response);
 461     odr_setbuf(assoc->encode, 0, 0, 0); /* don't free if we abort later */
 462     odr_reset(assoc->encode);
 463     if (assoc->print && !z_APDU(assoc->print, &res, 0))
 464     {
 465         logf(LOG_WARN, "ODR print error: %s",
 466             odr_errlist[odr_geterror(assoc->print)]);
 467         odr_reset(assoc->print);
 468     }
 469     /* change this when we make the backend reentrant */
 470     assert(req == request_head(&assoc->incoming));
 471     req->state = REQUEST_IDLE;
 472     request_deq(&assoc->incoming);
 473     request_enq(&assoc->outgoing, req);
 474     /* turn the work over to the ir_session handler */
 475     iochan_setflag(assoc->client_chan, EVENT_OUTPUT);
 476     /* Is there more work to be done? give that to the input handler too */
 477     if (request_head(&assoc->incoming))
 478         iochan_setevent(assoc->client_chan, EVENT_WORK);
 479     return 0;
 480 }
 481
 482 /*
 483  * Handle init request.
 484  * At the moment, we don't check the protocol version or the options
 485  * anywhere else in the code - we just don't do anything that would
 486  * break a naive client.
 487  */
 488 static Z_APDU *process_initRequest(association *assoc, request *reqb)
 489 {
 490     Z_InitRequest *req = reqb->request->u.initRequest;
 491     static Z_APDU apdu;
 492     static Z_InitResponse resp;
 493     static bool_t result = 1;
 494     static Odr_bitmask options, protocolVersion;
 495     bend_initrequest binitreq;
 496     bend_initresult *binitres;
 497
 498     logf(LOG_LOG, "Got initRequest");
 499     if (req->implementationId)
 500         logf(LOG_LOG, "Id:        %s", req->implementationId);
 501     if (req->implementationName)
 502         logf(LOG_LOG, "Name:      %s", req->implementationName);
 503     if (req->implementationVersion)
 504         logf(LOG_LOG, "Version:   %s", req->implementationVersion);
 505
 506     binitreq.configname = "default-config";
 507     binitreq.auth = req->idAuthentication;
 508     if (!(binitres = bend_init(&binitreq)))
 509     {
 510         logf(LOG_WARN, "Bad response from backend.");
 511         return 0;
 512     }
 513
 514     assoc->backend = binitres->handle;
 515     apdu.which = Z_APDU_initResponse;
 516     apdu.u.initResponse = &resp;
 517     resp.referenceId = req->referenceId;
 518     /* let's tell the client what we can do */
 519     ODR_MASK_ZERO(&options);
 520     if (ODR_MASK_GET(req->options, Z_Options_search))
 521         ODR_MASK_SET(&options, Z_Options_search);
 522     if (ODR_MASK_GET(req->options, Z_Options_present))
 523         ODR_MASK_SET(&options, Z_Options_present);
 524 #if 0
 525     if (ODR_MASK_GET(req->options, Z_Options_delSet))
 526         ODR_MASK_SET(&options, Z_Options_delSet);
 527 #endif
 528     if (ODR_MASK_GET(req->options, Z_Options_namedResultSets))
 529         ODR_MASK_SET(&options, Z_Options_namedResultSets);
 530     if (ODR_MASK_GET(req->options, Z_Options_scan))
 531         ODR_MASK_SET(&options, Z_Options_scan);
 532     if (ODR_MASK_GET(req->options, Z_Options_concurrentOperations))
 533         ODR_MASK_SET(&options, Z_Options_concurrentOperations);
 534     resp.options = &options;
 535
 536     ODR_MASK_ZERO(&protocolVersion);
 537     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_1))
 538         ODR_MASK_SET(&protocolVersion, Z_ProtocolVersion_1);
 539     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_2))
 540         ODR_MASK_SET(&protocolVersion, Z_ProtocolVersion_2);
 541     resp.protocolVersion = &protocolVersion;
 542     assoc->maximumRecordSize = *req->maximumRecordSize;
 543     if (assoc->maximumRecordSize > control_block->maxrecordsize)
 544         assoc->maximumRecordSize = control_block->maxrecordsize;
 545     assoc->preferredMessageSize = *req->preferredMessageSize;
 546     if (assoc->preferredMessageSize > assoc->maximumRecordSize)
 547         assoc->preferredMessageSize = assoc->maximumRecordSize;
 548     resp.preferredMessageSize = &assoc->preferredMessageSize;
 549     resp.maximumRecordSize = &assoc->maximumRecordSize;
 550     resp.result = &result;
 551     resp.implementationId = "YAZ";
 552     resp.implementationName = "Index Data/YAZ Generic Frontend Server";
 553     resp.implementationVersion = YAZ_VERSION;
 554     resp.userInformationField = 0;
 555     if (binitres->errcode)
 556     {
 557         logf(LOG_LOG, "Connection rejected by backend.");
 558         result = 0;
 559         assoc->rejected = 1;
 560     }
 561     return &apdu;
 562 }
 563
 564 /*
 565  * These functions should be merged.
 566  */
 567
 568 /*
 569  * nonsurrogate diagnostic record.
 570  */
 571 static Z_Records *diagrec(oid_proto proto, int error, char *addinfo)
 572 {
 573     static Z_Records rec;
 574     oident bib1;
 575     static Z_DiagRec dr;
 576     static int err;
 577
 578     bib1.proto = proto;
 579     bib1.class = CLASS_DIAGSET;
 580     bib1.value = VAL_BIB1;
 581
 582     logf(LOG_DEBUG, "Diagnostic: %d -- %s", error, addinfo ? addinfo :
 583         "NULL");
 584     err = error;
 585     rec.which = Z_Records_NSD;
 586     rec.u.nonSurrogateDiagnostic = &dr;
 587     dr.diagnosticSetId = oid_getoidbyent(&bib1);
 588     dr.condition = &err;
 589     dr.addinfo = addinfo ? addinfo : "";
 590     return &rec;
 591 }
 592
 593 /*
 594  * surrogate diagnostic.
 595  */
 596 static Z_NamePlusRecord *surrogatediagrec(oid_proto proto, char *dbname,
 597                                             int error, char *addinfo)
 598 {
 599     static Z_NamePlusRecord rec;
 600     static Z_DiagRec dr;
 601     static int err;
 602     oident bib1;
 603
 604     bib1.proto = proto;
 605     bib1.class = CLASS_DIAGSET;
 606     bib1.value = VAL_BIB1;
 607
 608     logf(LOG_DEBUG, "SurrogateDiagnotic: %d -- %s", error, addinfo);
 609     err = error;
 610     rec.databaseName = dbname;
 611     rec.which = Z_NamePlusRecord_surrogateDiagnostic;
 612     rec.u.surrogateDiagnostic = &dr;
 613     dr.diagnosticSetId = oid_getoidbyent(&bib1);
 614     dr.condition = &err;
 615     dr.addinfo = addinfo ? addinfo : "";
 616     return &rec;
 617 }
 618
 619 /*
 620  * multiple nonsurrogate diagnostics.
 621  */
 622 static Z_DiagRecs *diagrecs(oid_proto proto, int error, char *addinfo)
 623 {
 624     static Z_DiagRecs recs;
 625     static Z_DiagRec *recp[1], rec;
 626     static int err;
 627     oident bib1;
 628
 629     logf(LOG_DEBUG, "DiagRecs: %d -- %s", error, addinfo);
 630     bib1.proto = proto;
 631     bib1.class = CLASS_DIAGSET;
 632     bib1.value = VAL_BIB1;
 633
 634     err = error;
 635     recs.num_diagRecs = 1;
 636     recs.diagRecs = recp;
 637     recp[0] = &rec;
 638     rec.diagnosticSetId = oid_getoidbyent(&bib1);
 639     rec.condition = &err;
 640     rec.addinfo = addinfo ? addinfo : "";
 641     return &recs;
 642 }
 643
 644 #define MAX_RECORDS 256
 645
 646 static Z_Records *pack_records(association *a, char *setname, int start,
 647                                 int *num, Z_ElementSetNames *esn,
 648                                 int *next, int *pres)
 649 {
 650     int recno, total_length = 0, toget = *num;
 651     static Z_Records records;
 652     static Z_NamePlusRecordList reclist;
 653     static Z_NamePlusRecord *list[MAX_RECORDS];
 654     oident recform;
 655     Odr_oid *oid;
 656
 657     records.which = Z_Records_DBOSD;
 658     records.u.databaseOrSurDiagnostics = &reclist;
 659     reclist.num_records = 0;
 660     reclist.records = list;
 661     *pres = Z_PRES_SUCCESS;
 662     *num = 0;
 663     *next = 0;
 664
 665     recform.proto = a->proto;
 666     recform.class = CLASS_RECSYN;
 667     recform.value = VAL_USMARC;
 668     if (!(oid = odr_oiddup(a->encode, oid_getoidbyent(&recform))))
 669         return 0;
 670
 671     logf(LOG_DEBUG, "Request to pack %d+%d", start, toget);
 672     logf(LOG_DEBUG, "pms=%d, mrs=%d", a->preferredMessageSize,
 673         a->maximumRecordSize);
 674     for (recno = start; reclist.num_records < toget; recno++)
 675     {
 676         bend_fetchrequest freq;
 677         bend_fetchresult *fres;
 678         Z_NamePlusRecord *thisrec;
 679         Z_DatabaseRecord *thisext;
 680
 681         if (reclist.num_records == MAX_RECORDS - 1)
 682         {
 683             *pres = Z_PRES_PARTIAL_2;
 684             break;
 685         }
 686         freq.setname = setname;
 687         freq.number = recno;
 688         if (!(fres = bend_fetch(a->backend, &freq, 0)))
 689         {
 690             *pres = Z_PRES_FAILURE;
 691             return diagrec(a->proto, 2, "Backend interface problem");
 692         }
 693         /* backend should be able to signal whether error is system-wide
 694            or only pertaining to current record */
 695         if (fres->errcode)
 696         {
 697             *pres = Z_PRES_FAILURE;
 698             return diagrec(a->proto, fres->errcode, fres->errstring);
 699         }
 700         logf(LOG_DEBUG, "  fetched record, len=%d, total=%d",
 701             fres->len, total_length);
 702         if (fres->len + total_length > a->preferredMessageSize)
 703         {
 704             /* record is small enough, really */
 705             if (fres->len <= a->preferredMessageSize)
 706             {
 707                 logf(LOG_DEBUG, "  Dropped last normal-sized record");
 708                 *pres = Z_PRES_PARTIAL_2;
 709                 break;
 710             }
 711             /* record can only be fetched by itself */
 712             if (fres->len < a->maximumRecordSize)
 713             {
 714                 logf(LOG_DEBUG, "  Record > prefmsgsz");
 715                 if (toget > 1)
 716                 {
 717                     logf(LOG_DEBUG, "  Dropped it");
 718                     reclist.records[reclist.num_records] =
 719                          surrogatediagrec(a->proto, fres->basename, 16, 0);
 720                     reclist.num_records++;
 721                     total_length += 10; /* totally arbitrary */
 722                     continue;
 723                 }
 724             }
 725             else /* too big entirely */
 726             {
 727                 logf(LOG_DEBUG, "Record > maxrcdsz");
 728                 reclist.records[reclist.num_records] =
 729                     surrogatediagrec(a->proto, fres->basename, 17, 0);
 730                 reclist.num_records++;
 731                 total_length += 10; /* totally arbitrary */
 732                 continue;
 733             }
 734         }
 735         if (!(thisrec = odr_malloc(a->encode, sizeof(*thisrec))))
 736             return 0;
 737         if (!(thisrec->databaseName = odr_malloc(a->encode,
 738             strlen(fres->basename) + 1)))
 739             return 0;
 740         strcpy(thisrec->databaseName, fres->basename);
 741         thisrec->which = Z_NamePlusRecord_databaseRecord;
 742         if (!(thisrec->u.databaseRecord = thisext = odr_malloc(a->encode,
 743             sizeof(Z_DatabaseRecord))))
 744             return 0;
 745         thisext->direct_reference = oid; /* should be OID for current MARC */
 746         thisext->indirect_reference = 0;
 747         thisext->descriptor = 0;
 748         thisext->which = ODR_EXTERNAL_octet;
 749         if (!(thisext->u.octet_aligned = odr_malloc(a->encode,
 750             sizeof(Odr_oct))))
 751             return 0;
 752         if (!(thisext->u.octet_aligned->buf = odr_malloc(a->encode, fres->len)))
 753             return 0;
 754         memcpy(thisext->u.octet_aligned->buf, fres->record, fres->len);
 755         thisext->u.octet_aligned->len = thisext->u.octet_aligned->size =
 756             fres->len;
 757         reclist.records[reclist.num_records] = thisrec;
 758         reclist.num_records++;
 759         total_length += fres->len;
 760         *next = fres->last_in_set ? 0 : recno + 1;
 761     }
 762     *num = reclist.num_records;
 763     return &records;
 764 }
 765
 766 static Z_APDU *process_searchRequest(association *assoc, request *reqb,
 767     int *fd)
 768 {
 769     Z_SearchRequest *req = reqb->request->u.searchRequest;
 770     bend_searchrequest bsrq;
 771     bend_searchresult *bsrt;
 772
 773     logf(LOG_LOG, "Got SearchRequest.");
 774
 775     bsrq.setname = req->resultSetName;
 776     bsrq.replace_set = *req->replaceIndicator;
 777     bsrq.num_bases = req->num_databaseNames;
 778     bsrq.basenames = req->databaseNames;
 779     bsrq.query = req->query;
 780
 781     if (!(bsrt = bend_search(assoc->backend, &bsrq, fd)))
 782         return 0;
 783     return response_searchRequest(assoc, reqb, bsrt, fd);
 784 }
 785
 786 bend_searchresult *bend_searchresponse(void *handle) {return 0;}
 787
 788 /*
 789  * Prepare a searchresponse based on the backend results. We probably want
 790  * to look at making the fetching of records nonblocking as well, but
 791  * so far, we'll keep things simple.
 792  * If bsrt is null, that means we're called in response to a communications
 793  * event, and we'll have to get the response for ourselves.
 794  */
 795 static Z_APDU *response_searchRequest(association *assoc, request *reqb,
 796     bend_searchresult *bsrt, int *fd)
 797 {
 798     Z_SearchRequest *req = reqb->request->u.searchRequest;
 799     static Z_APDU apdu;
 800     static Z_SearchResponse resp;
 801     static int nulint = 0;
 802     static bool_t sr = 1;
 803     static int next = 0;
 804     static int none = Z_RES_NONE;
 805
 806     apdu.which = Z_APDU_searchResponse;
 807     apdu.u.searchResponse = &resp;
 808     resp.referenceId = req->referenceId;
 809     *fd = -1;
 810     if (!bsrt && !(bsrt = bend_searchresponse(assoc->backend)))
 811     {
 812         logf(LOG_FATAL, "Bad result from backend");
 813         return 0;
 814     }
 815     else if (bsrt->errcode)
 816     {
 817         resp.records = diagrec(assoc->proto, bsrt->errcode,
 818             bsrt->errstring);
 819         resp.resultCount = &nulint;
 820         resp.numberOfRecordsReturned = &nulint;
 821         resp.nextResultSetPosition = &nulint;
 822         resp.searchStatus = &nulint;
 823         resp.resultSetStatus = &none;
 824         resp.presentStatus = 0;
 825     }
 826     else
 827     {
 828         int toget;
 829         Z_ElementSetNames *setnames;
 830         int presst = 0;
 831
 832         resp.records = 0;
 833         resp.resultCount = &bsrt->hits;
 834
 835         /* how many records does the user agent want, then? */
 836         if (bsrt->hits <= *req->smallSetUpperBound)
 837         {
 838             toget = bsrt->hits;
 839             setnames = req->smallSetElementSetNames;
 840         }
 841         else if (bsrt->hits < *req->largeSetLowerBound)
 842         {
 843             toget = *req->mediumSetPresentNumber;
 844             if (toget > bsrt->hits)
 845                 toget = bsrt->hits;
 846             setnames = req->mediumSetElementSetNames;
 847         }
 848         else
 849             toget = 0;
 850
 851         if (toget && !resp.records)
 852         {
 853             resp.records = pack_records(assoc, req->resultSetName, 1,
 854                 &toget, setnames, &next, &presst);
 855             if (!resp.records)
 856                 return 0;
 857             resp.numberOfRecordsReturned = &toget;
 858             resp.nextResultSetPosition = &next;
 859             resp.searchStatus = &sr;
 860             resp.resultSetStatus = 0;
 861             resp.presentStatus = &presst;
 862         }
 863         else
 864         {
 865             resp.numberOfRecordsReturned = &nulint;
 866             resp.nextResultSetPosition = &next;
 867             resp.searchStatus = &sr;
 868             resp.resultSetStatus = 0;
 869             resp.presentStatus = 0;
 870         }
 871     }
 872     return &apdu;
 873 }
 874
 875 /*
 876  * Maybe we got a little over-friendly when we designed bend_fetch to
 877  * get only one record at a time. Some backends can optimise multiple-record
 878  * fetches, and at any rate, there is some overhead involved in
 879  * all that selecting and hopping around. Problem is, of course, that the
 880  * frontend can't know ahead of time how many records it'll need to
 881  * fill the negotiated PDU size. Annoying. Segmentation or not, Z/SR
 882  * is downright lousy as a bulk data transfer protocol.
 883  *
 884  * To start with, we'll do the fetching of records from the backend
 885  * in one operation: To save some trips in and out of the event-handler,
 886  * and to simplify the interface to pack_records. At any rate, asynch
 887  * operation is more fun in operations that have an unpredictable execution
 888  * speed - which is normally more true for search than for present.
 889  */
 890 static Z_APDU *process_presentRequest(association *assoc, request *reqb,
 891     int *fd)
 892 {
 893     Z_PresentRequest *req = reqb->request->u.presentRequest;
 894     static Z_APDU apdu;
 895     static Z_PresentResponse resp;
 896     static int presst, next, num;
 897
 898     logf(LOG_LOG, "Got PresentRequest.");
 899     apdu.which = Z_APDU_presentResponse;
 900     apdu.u.presentResponse = &resp;
 901     resp.referenceId = req->referenceId;
 902
 903     num = *req->numberOfRecordsRequested;
 904     resp.records = pack_records(assoc, req->resultSetId,
 905         *req->resultSetStartPoint, &num, req->elementSetNames, &next, &presst);
 906     if (!resp.records)
 907         return 0;
 908     resp.numberOfRecordsReturned = &num;
 909     resp.presentStatus = &presst;
 910     resp.nextResultSetPosition = &next;
 911
 912     return &apdu;
 913 }
 914
 915 /*
 916  * Scan was implemented rather in a hurry, and with support for only the basic
 917  * elements of the service in the backend API. Suggestions are welcome.
 918  */
 919 static Z_APDU *process_scanRequest(association *assoc, request *reqb, int *fd)
 920 {
 921     Z_ScanRequest *req = reqb->request->u.scanRequest;
 922     static Z_APDU apdu;
 923     static Z_ScanResponse res;
 924     static int scanStatus = Z_Scan_failure;
 925     static int numberOfEntriesReturned = 0;
 926     oident *attent;
 927     static Z_ListEntries ents;
 928 #define SCAN_MAX_ENTRIES 200
 929     static Z_Entry *tab[SCAN_MAX_ENTRIES];
 930     bend_scanrequest srq;
 931     bend_scanresult *srs;
 932
 933     apdu.which = Z_APDU_scanResponse;
 934     apdu.u.scanResponse = &res;
 935     res.referenceId = req->referenceId;
 936     res.stepSize = 0;
 937     res.scanStatus = &scanStatus;
 938     res.numberOfEntriesReturned = &numberOfEntriesReturned;
 939     res.positionOfTerm = 0;
 940     res.entries = &ents;
 941     ents.which = Z_ListEntries_nonSurrogateDiagnostics;
 942     res.attributeSet = 0;
 943
 944     if (req->attributeSet && (!(attent = oid_getentbyoid(req->attributeSet)) ||
 945         attent->class != CLASS_ATTSET || attent->value != VAL_BIB1))
 946         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 121, 0);
 947     else if (req->stepSize && *req->stepSize > 0)
 948         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 205, 0);
 949     else
 950     {
 951         srq.num_bases = req->num_databaseNames;
 952         srq.basenames = req->databaseNames;
 953         srq.num_entries = *req->numberOfTermsRequested;
 954         srq.term = req->termListAndStartPoint;
 955         srq.term_position = req->preferredPositionInResponse ?
 956             *req->preferredPositionInResponse : 1;
 957         if (!(srs = bend_scan(assoc->backend, &srq, 0)))
 958             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 2, 0);
 959         else if (srs->errcode)
 960             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto,
 961                 srs->errcode, srs->errstring);
 962         else
 963         {
 964             int i;
 965             static Z_Entries list;
 966
 967             if (srs->status == BEND_SCAN_PARTIAL)
 968                 scanStatus = Z_Scan_partial_5;
 969             else
 970                 scanStatus = Z_Scan_success;
 971             ents.which = Z_ListEntries_entries;
 972             ents.u.entries = &list;
 973             list.entries = tab;
 974             for (i = 0; i < srs->num_entries; i++)
 975             {
 976                 Z_Entry *e;
 977                 Z_TermInfo *t;
 978                 Odr_oct *o;
 979
 980                 if (i >= SCAN_MAX_ENTRIES)
 981                 {
 982                     scanStatus = Z_Scan_partial_4;
 983                     break;
 984                 }
 985                 list.entries[i] = e = odr_malloc(assoc->encode, sizeof(*e));
 986                 e->which = Z_Entry_termInfo;
 987                 e->u.termInfo = t = odr_malloc(assoc->encode, sizeof(*t));
 988                 t->suggestedAttributes = 0;
 989                 t->alternativeTerm = 0;
 990                 t->byAttributes = 0;
 991                 t->globalOccurrences = &srs->entries[i].occurrences;
 992                 t->term = odr_malloc(assoc->encode, sizeof(*t->term));
 993                 t->term->which = Z_Term_general;
 994                 t->term->u.general = o = odr_malloc(assoc->encode,
 995                     sizeof(Odr_oct));
 996                 o->buf = odr_malloc(assoc->encode, o->len = o->size =
 997                     strlen(srs->entries[i].term));
 998                 memcpy(o->buf, srs->entries[i].term, o->len);
 999             }
1000             list.num_entries = i;
1001             res.numberOfEntriesReturned = &list.num_entries;
1002             res.positionOfTerm = &srs->term_position;
1003         }
1004     }
1005
1006     return &apdu;
1007 }