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 1.37  1995-06-16 13:16:14  quinn
   8  * Fixed Defaultdiagformat.
   9  *
  10  * Revision 1.36  1995/06/16  10:31:36  quinn
  11  * Added session timeout.
  12  *
  13  * Revision 1.35  1995/06/15  07:45:14  quinn
  14  * Moving to v3.
  15  *
  16  * Revision 1.34  1995/06/14  15:26:46  quinn
  17  * *** empty log message ***
  18  *
  19  * Revision 1.33  1995/06/06  14:57:05  quinn
  20  * Better diagnostics.
  21  *
  22  * Revision 1.32  1995/06/06  08:41:44  quinn
  23  * Better diagnostics.
  24  *
  25  * Revision 1.31  1995/06/06  08:15:37  quinn
  26  * Cosmetic.
  27  *
  28  * Revision 1.30  1995/06/05  10:53:32  quinn
  29  * Added a better SCAN.
  30  *
  31  * Revision 1.29  1995/06/01  11:25:03  quinn
  32  * Smallish.
  33  *
  34  * Revision 1.28  1995/06/01  11:21:01  quinn
  35  * Attempting to fix a bug in pack-records. replaced break with continue
  36  * for large records, according to standard.
  37  *
  38  * Revision 1.27  1995/05/29  08:12:06  quinn
  39  * Moved oid to util
  40  *
  41  * Revision 1.26  1995/05/18  13:02:12  quinn
  42  * Smallish.
  43  *
  44  * Revision 1.25  1995/05/17  08:42:26  quinn
  45  * Transfer auth info to backend. Allow backend to reject init gracefully.
  46  *
  47  * Revision 1.24  1995/05/16  08:51:04  quinn
  48  * License, documentation, and memory fixes
  49  *
  50  * Revision 1.23  1995/05/15  13:25:10  quinn
  51  * Fixed memory bug.
  52  *
  53  * Revision 1.22  1995/05/15  11:56:39  quinn
  54  * Asynchronous facilities. Restructuring of seshigh code.
  55  *
  56  * Revision 1.21  1995/05/02  08:53:19  quinn
  57  * Trying in vain to fix comm with ISODE
  58  *
  59  * Revision 1.20  1995/04/20  15:13:00  quinn
  60  * Cosmetic
  61  *
  62  * Revision 1.19  1995/04/18  08:15:34  quinn
  63  * Added dynamic memory allocation on encoding (whew). Code is now somewhat
  64  * neater. We'll make the same change for decoding one day.
  65  *
  66  * Revision 1.18  1995/04/17  11:28:25  quinn
  67  * Smallish
  68  *
  69  * Revision 1.17  1995/04/10  10:23:36  quinn
  70  * Some work to add scan and other things.
  71  *
  72  * Revision 1.16  1995/03/31  09:18:55  quinn
  73  * Added logging.
  74  *
  75  * Revision 1.15  1995/03/30  14:03:23  quinn
  76  * Added RFC1006 as separate library
  77  *
  78  * Revision 1.14  1995/03/30  12:18:17  quinn
  79  * Fixed bug.
  80  *
  81  * Revision 1.13  1995/03/30  09:09:24  quinn
  82  * Added state-handle and some support for asynchronous activities.
  83  *
  84  * Revision 1.12  1995/03/29  15:40:16  quinn
  85  * Ongoing work. Statserv is now dynamic by default
  86  *
  87  * Revision 1.11  1995/03/28  09:16:21  quinn
  88  * Added record packing to the search request
  89  *
  90  * Revision 1.10  1995/03/27  08:34:24  quinn
  91  * Added dynamic server functionality.
  92  * Released bindings to session.c (is now redundant)
  93  *
  94  * Revision 1.9  1995/03/22  15:01:26  quinn
  95  * Adjusting record packing.
  96  *
  97  * Revision 1.8  1995/03/22  10:13:21  quinn
  98  * Working on record packer
  99  *
 100  * Revision 1.7  1995/03/21  15:53:31  quinn
 101  * Little changes.
 102  *
 103  * Revision 1.6  1995/03/21  12:30:09  quinn
 104  * Beginning to add support for record packing.
 105  *
 106  * Revision 1.5  1995/03/17  10:44:13  quinn
 107  * Added catch of null-string in makediagrec
 108  *
 109  * Revision 1.4  1995/03/17  10:18:08  quinn
 110  * Added memory management.
 111  *
 112  * Revision 1.3  1995/03/16  17:42:39  quinn
 113  * Little changes
 114  *
 115  * Revision 1.2  1995/03/16  13:29:01  quinn
 116  * Partitioned server.
 117  *
 118  * Revision 1.1  1995/03/15  16:02:10  quinn
 119  * Modded session.c to seshigh.c
 120  *
 121  */
 122
 123 /*
 124  * Frontend server logic.
 125  *
 126  * This code receives incoming APDUs, and handles client requests by means
 127  * of the backend API.
 128  *
 129  * Some of the code is getting quite involved, compared to simpler servers -
 130  * primarily because it is asynchronous both in the communication with
 131  * the user and the backend. We think the complexity will pay off in
 132  * the form of greater flexibility when more asynchronous facilities
 133  * are implemented.
 134  *
 135  * Memory management has become somewhat involved. In the simple case, where
 136  * only one PDU is pending at a time, it will simply reuse the same memory,
 137  * once it has found its working size. When we enable multiple concurrent
 138  * operations, perhaps even with multiple parallel calls to the backend, it
 139  * will maintain a pool of buffers for encoding and decoding, trying to
 140  * minimize memory allocation/deallocation during normal operation.
 141  *
 142  * TODOs include (and will be done in order of public interest):
 143  *
 144  * Support for EXPLAIN - provide simple meta-database system.
 145  * Support for access control.
 146  * Support for resource control.
 147  * Support for extended services - primarily Item Order.
 148  * Rest of Z39.50-1994
 149  *
 150  */
 151
 152 #include <stdlib.h>
 153 #include <stdio.h>
 154 #include <unistd.h>
 155 #include <assert.h>
 156
 157 #include <dmalloc.h>
 158 #include <comstack.h>
 159 #include <eventl.h>
 160 #include <session.h>
 161 #include <proto.h>
 162 #include <oid.h>
 163 #include <log.h>
 164 #include <statserv.h>
 165
 166 #include <backend.h>
 167
 168 static int process_request(association *assoc);
 169 void backend_response(IOCHAN i, int event);
 170 static int process_response(association *assoc, request *req, Z_APDU *res);
 171 static Z_APDU *process_initRequest(association *assoc, request *reqb);
 172 static Z_APDU *process_searchRequest(association *assoc, request *reqb,
 173     int *fd);
 174 static Z_APDU *response_searchRequest(association *assoc, request *reqb,
 175     bend_searchresult *bsrt, int *fd);
 176 static Z_APDU *process_presentRequest(association *assoc, request *reqb,
 177     int *fd);
 178 static Z_APDU *process_scanRequest(association *assoc, request *reqb, int *fd);
 179
 180 static FILE *apduf = 0; /* for use in static mode */
 181 static statserv_options_block *control_block = 0;
 182
 183 /*
 184  * Create and initialize a new association-handle.
 185  *  channel  : iochannel for the current line.
 186  *  link     : communications channel.
 187  * Returns: 0 or a new association handle.
 188  */
 189 association *create_association(IOCHAN channel, COMSTACK link)
 190 {
 191     association *new;
 192
 193     if (!control_block)
 194         control_block = statserv_getcontrol();
 195     if (!(new = malloc(sizeof(*new))))
 196         return 0;
 197     new->client_chan = channel;
 198     new->client_link = link;
 199     if (!(new->decode = odr_createmem(ODR_DECODE)) ||
 200         !(new->encode = odr_createmem(ODR_ENCODE)))
 201         return 0;
 202     if (*control_block->apdufile)
 203     {
 204         char filename[256];
 205         FILE *f;
 206
 207         strcpy(filename, control_block->apdufile);
 208         if (!(new->print = odr_createmem(ODR_PRINT)))
 209             return 0;
 210         if (*control_block->apdufile != '-')
 211         {
 212             strcpy(filename, control_block->apdufile);
 213             if (!control_block->dynamic)
 214             {
 215                 if (!apduf)
 216                 {
 217                     if (!(apduf = fopen(filename, "w")))
 218                     {
 219                         logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 220                         return 0;
 221                     }
 222                     setvbuf(apduf, 0, _IONBF, 0);
 223                 }
 224                 f = apduf;
 225             }
 226             else
 227             {
 228                 sprintf(filename + strlen(filename), ".%d", getpid());
 229                 if (!(f = fopen(filename, "w")))
 230                 {
 231                     logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 232                     return 0;
 233                 }
 234                 setvbuf(f, 0, _IONBF, 0);
 235             }
 236             odr_setprint(new->print, f);
 237         }
 238     }
 239     else
 240         new->print = 0;
 241     new->input_buffer = 0;
 242     new->input_buffer_len = 0;
 243     new->backend = 0;
 244     new->rejected = 0;
 245     request_initq(&new->incoming);
 246     request_initq(&new->outgoing);
 247     new->proto = cs_getproto(link);
 248     return new;
 249 }
 250
 251 /*
 252  * Free association and release resources.
 253  */
 254 void destroy_association(association *h)
 255 {
 256     odr_destroy(h->decode);
 257     odr_destroy(h->encode);
 258     if (h->print)
 259         odr_destroy(h->print);
 260     if (h->input_buffer)
 261         free(h->input_buffer);
 262     if (h->backend)
 263         bend_close(h->backend);
 264     while (request_deq(&h->incoming));
 265     while (request_deq(&h->outgoing));
 266     free(h);
 267 }
 268
 269 /*
 270  * This is where PDUs from the client are read and the further
 271  * processing is initiated. Flow of control moves down through the
 272  * various process_* functions below, until the encoded result comes back up
 273  * to the output handler in here.
 274  *
 275  *  h     : the I/O channel that has an outstanding event.
 276  *  event : the current outstanding event.
 277  */
 278 void ir_session(IOCHAN h, int event)
 279 {
 280     int res;
 281     association *assoc = iochan_getdata(h);
 282     COMSTACK conn = assoc->client_link;
 283     request *req;
 284
 285     assert(h && conn && assoc);
 286     if (event == EVENT_TIMEOUT)
 287     {
 288         logf(LOG_LOG, "Timeout - closing connection.");
 289         cs_close(conn);
 290         destroy_association(assoc);
 291         iochan_destroy(h);
 292         return;
 293     }
 294     if (event & EVENT_INPUT || event & EVENT_WORK) /* input */
 295     {
 296         if (event & EVENT_INPUT)
 297         {
 298             logf(LOG_DEBUG, "ir_session (input)");
 299             assert(assoc && conn);
 300             /* We aren't speaking to this fellow */
 301             if (assoc->rejected)
 302             {
 303                 logf(LOG_LOG, "Closed connection after reject");
 304                 cs_close(conn);
 305                 destroy_association(assoc);
 306                 iochan_destroy(h);
 307                 return;
 308             }
 309             if ((res = cs_get(conn, &assoc->input_buffer,
 310                 &assoc->input_buffer_len)) <= 0)
 311             {
 312                 logf(LOG_LOG, "Connection closed by client");
 313                 cs_close(conn);
 314                 destroy_association(assoc);
 315                 iochan_destroy(h);
 316                 return;
 317             }
 318             else if (res == 1) /* incomplete read - wait for more  */
 319                 return;
 320             if (cs_more(conn)) /* more stuff - call us again later, please */
 321                 iochan_setevent(h, EVENT_INPUT);
 322
 323             /* we got a complete PDU. Let's decode it */
 324             logf(LOG_DEBUG, "Got PDU, %d bytes", res);
 325             req = request_get(); /* get a new request structure */
 326             odr_reset(assoc->decode);
 327             odr_setbuf(assoc->decode, assoc->input_buffer, res, 0);
 328             if (!z_APDU(assoc->decode, &req->request, 0))
 329             {
 330                 logf(LOG_WARN, "ODR error: %s",
 331                     odr_errlist[odr_geterror(assoc->decode)]);
 332                 cs_close(conn);
 333                 destroy_association(assoc);
 334                 iochan_destroy(h);
 335                 return;
 336             }
 337             req->request_mem = odr_extract_mem(assoc->decode);
 338             if (assoc->print && !z_APDU(assoc->print, &req->request, 0))
 339             {
 340                 logf(LOG_WARN, "ODR print error: %s",
 341                     odr_errlist[odr_geterror(assoc->print)]);
 342                 odr_reset(assoc->print);
 343             }
 344             request_enq(&assoc->incoming, req);
 345         }
 346
 347         /* can we do something yet? */
 348         req = request_head(&assoc->incoming);
 349         if (req->state == REQUEST_IDLE)
 350             if (process_request(assoc) < 0)
 351             {
 352                 cs_close(conn);
 353                 destroy_association(assoc);
 354                 iochan_destroy(h);
 355             }
 356     }
 357     if (event & EVENT_OUTPUT)
 358     {
 359         request *req = request_head(&assoc->outgoing);
 360
 361         logf(LOG_DEBUG, "ir_session (output)");
 362         req->state = REQUEST_PENDING;
 363         switch (res = cs_put(conn, req->response, req->len_response))
 364         {
 365             case -1:
 366                 logf(LOG_LOG, "Connection closed by client");
 367                 cs_close(conn);
 368                 destroy_association(assoc);
 369                 iochan_destroy(h);
 370                 break;
 371             case 0: /* all sent - release the request structure */
 372                 logf(LOG_DEBUG, "Wrote PDU, %d bytes", req->len_response);
 373                 odr_release_mem(req->request_mem);
 374                 request_deq(&assoc->outgoing);
 375                 request_release(req);
 376                 if (!request_head(&assoc->outgoing))
 377                     iochan_clearflag(h, EVENT_OUTPUT);
 378                 break;
 379             /* value of 1 -- partial send -- is simply ignored */
 380         }
 381     }
 382     if (event & EVENT_EXCEPT)
 383     {
 384         logf(LOG_DEBUG, "ir_session (exception)");
 385         cs_close(conn);
 386         destroy_association(assoc);
 387         iochan_destroy(h);
 388     }
 389 }
 390
 391 /*
 392  * Initiate request processing.
 393  */
 394 static int process_request(association *assoc)
 395 {
 396     request *req = request_head(&assoc->incoming);
 397     int fd = -1;
 398     Z_APDU *res;
 399
 400     logf(LOG_DEBUG, "process_request");
 401     assert(req && req->state == REQUEST_IDLE);
 402     switch (req->request->which)
 403     {
 404         case Z_APDU_initRequest:
 405             res = process_initRequest(assoc, req); break;
 406         case Z_APDU_searchRequest:
 407             res = process_searchRequest(assoc, req, &fd); break;
 408         case Z_APDU_presentRequest:
 409             res = process_presentRequest(assoc, req, &fd); break;
 410         case Z_APDU_scanRequest:
 411             res = process_scanRequest(assoc, req, &fd); break;
 412         default:
 413             logf(LOG_WARN, "Bad APDU received");
 414             return -1;
 415     }
 416     if (res)
 417     {
 418         logf(LOG_DEBUG, "  result immediately available");
 419         return process_response(assoc, req, res);
 420     }
 421     else if (fd < 0)
 422     {
 423         logf(LOG_WARN, "   bad result");
 424         return -1;
 425     }
 426     else /* no result yet - one will be provided later */
 427     {
 428         IOCHAN chan;
 429
 430         /* Set up an I/O handler for the fd supplied by the backend */
 431
 432         logf(LOG_DEBUG, "   establishing handler for result");
 433         req->state = REQUEST_PENDING;
 434         if (!(chan = iochan_create(fd, backend_response, EVENT_INPUT)))
 435             abort();
 436         iochan_setdata(chan, assoc);
 437         return 0;
 438     }
 439 }
 440
 441 /*
 442  * Handle message from the backend.
 443  */
 444 void backend_response(IOCHAN i, int event)
 445 {
 446     association *assoc = iochan_getdata(i);
 447     request *req = request_head(&assoc->incoming);
 448     Z_APDU *res;
 449     int fd;
 450
 451     logf(LOG_DEBUG, "backend_response");
 452     assert(assoc && req && req->state != REQUEST_IDLE);
 453     /* determine what it is we're waiting for */
 454     switch (req->request->which)
 455     {
 456         case Z_APDU_searchRequest:
 457             res = response_searchRequest(assoc, req, 0, &fd); break;
 458 #if 0
 459         case Z_APDU_presentRequest:
 460             res = response_presentRequest(assoc, req, 0, &fd); break;
 461         case Z_APDU_scanRequest:
 462             res = response_scanRequest(assoc, req, 0, &fd); break;
 463 #endif
 464         default:
 465             logf(LOG_WARN, "Serious programmer's lapse or bug");
 466             abort();
 467     }
 468     if ((res && process_response(assoc, req, res) < 0) || fd < 0)
 469     {
 470         logf(LOG_LOG, "Fatal error when talking to backend");
 471         cs_close(assoc->client_link);
 472         destroy_association(assoc);
 473         iochan_destroy(assoc->client_chan);
 474         iochan_destroy(i);
 475         return;
 476     }
 477     else if (!res) /* no result yet - try again later */
 478     {
 479         logf(LOG_DEBUG, "   no result yet");
 480         iochan_setfd(i, fd); /* in case fd has changed */
 481     }
 482 }
 483
 484 /*
 485  * Encode response, and transfer the request structure to the outgoing queue.
 486  */
 487 static int process_response(association *assoc, request *req, Z_APDU *res)
 488 {
 489     odr_setbuf(assoc->encode, req->response, req->size_response, 1);
 490     if (!z_APDU(assoc->encode, &res, 0))
 491     {
 492         logf(LOG_WARN, "ODR error when encoding response: %s",
 493             odr_errlist[odr_geterror(assoc->decode)]);
 494         return -1;
 495     }
 496     req->response = odr_getbuf(assoc->encode, &req->len_response,
 497         &req->size_response);
 498     odr_setbuf(assoc->encode, 0, 0, 0); /* don't free if we abort later */
 499     odr_reset(assoc->encode);
 500     if (assoc->print && !z_APDU(assoc->print, &res, 0))
 501     {
 502         logf(LOG_WARN, "ODR print error: %s",
 503             odr_errlist[odr_geterror(assoc->print)]);
 504         odr_reset(assoc->print);
 505     }
 506     /* change this when we make the backend reentrant */
 507     assert(req == request_head(&assoc->incoming));
 508     req->state = REQUEST_IDLE;
 509     request_deq(&assoc->incoming);
 510     request_enq(&assoc->outgoing, req);
 511     /* turn the work over to the ir_session handler */
 512     iochan_setflag(assoc->client_chan, EVENT_OUTPUT);
 513     /* Is there more work to be done? give that to the input handler too */
 514     if (request_head(&assoc->incoming))
 515         iochan_setevent(assoc->client_chan, EVENT_WORK);
 516     return 0;
 517 }
 518
 519 /*
 520  * Handle init request.
 521  * At the moment, we don't check the protocol version or the options
 522  * anywhere else in the code - we just try not to do anything that would
 523  * break a naive client. We'll toss 'em into the association block when
 524  * we need them there.
 525  */
 526 static Z_APDU *process_initRequest(association *assoc, request *reqb)
 527 {
 528     Z_InitRequest *req = reqb->request->u.initRequest;
 529     Z_APDU *apdu = zget_APDU(assoc->encode, Z_APDU_initResponse);
 530     Z_InitResponse *resp = apdu->u.initResponse;
 531     bend_initrequest binitreq;
 532     bend_initresult *binitres;
 533
 534     logf(LOG_LOG, "Got initRequest");
 535     if (req->implementationId)
 536         logf(LOG_LOG, "Id:        %s", req->implementationId);
 537     if (req->implementationName)
 538         logf(LOG_LOG, "Name:      %s", req->implementationName);
 539     if (req->implementationVersion)
 540         logf(LOG_LOG, "Version:   %s", req->implementationVersion);
 541
 542     binitreq.configname = "default-config";
 543     binitreq.auth = req->idAuthentication;
 544     if (!(binitres = bend_init(&binitreq)))
 545     {
 546         logf(LOG_WARN, "Bad response from backend.");
 547         return 0;
 548     }
 549
 550     assoc->backend = binitres->handle;
 551     resp->referenceId = req->referenceId;
 552     /* let's tell the client what we can do */
 553     if (ODR_MASK_GET(req->options, Z_Options_search))
 554         ODR_MASK_SET(resp->options, Z_Options_search);
 555     if (ODR_MASK_GET(req->options, Z_Options_present))
 556         ODR_MASK_SET(resp->options, Z_Options_present);
 557 #if 0
 558     if (ODR_MASK_GET(req->options, Z_Options_delSet))
 559         ODR_MASK_SET(&options, Z_Options_delSet);
 560 #endif
 561     if (ODR_MASK_GET(req->options, Z_Options_namedResultSets))
 562         ODR_MASK_SET(resp->options, Z_Options_namedResultSets);
 563     if (ODR_MASK_GET(req->options, Z_Options_scan))
 564         ODR_MASK_SET(resp->options, Z_Options_scan);
 565     if (ODR_MASK_GET(req->options, Z_Options_concurrentOperations))
 566         ODR_MASK_SET(resp->options, Z_Options_concurrentOperations);
 567
 568     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_1))
 569         ODR_MASK_SET(resp->protocolVersion, Z_ProtocolVersion_1);
 570     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_2))
 571         ODR_MASK_SET(resp->protocolVersion, Z_ProtocolVersion_2);
 572     assoc->maximumRecordSize = *req->maximumRecordSize;
 573     if (assoc->maximumRecordSize > control_block->maxrecordsize)
 574         assoc->maximumRecordSize = control_block->maxrecordsize;
 575     assoc->preferredMessageSize = *req->preferredMessageSize;
 576     if (assoc->preferredMessageSize > assoc->maximumRecordSize)
 577         assoc->preferredMessageSize = assoc->maximumRecordSize;
 578     resp->preferredMessageSize = &assoc->preferredMessageSize;
 579     resp->maximumRecordSize = &assoc->maximumRecordSize;
 580     resp->implementationName = "Index Data/YAZ Generic Frontend Server";
 581     if (binitres->errcode)
 582     {
 583         logf(LOG_LOG, "Connection rejected by backend.");
 584         *resp->result = 0;
 585         assoc->rejected = 1;
 586     }
 587     return apdu;
 588 }
 589
 590 /*
 591  * These functions should be merged.
 592  */
 593
 594 /*
 595  * nonsurrogate diagnostic record.
 596  */
 597 static Z_Records *diagrec(oid_proto proto, int error, char *addinfo)
 598 {
 599     static Z_Records rec;
 600     oident bib1;
 601     static int err;
 602 #ifdef Z_95
 603     static Z_DiagRec drec;
 604     static Z_DefaultDiagFormat dr;
 605 #else
 606     static Z_DiagRec dr;
 607 #endif
 608
 609     bib1.proto = proto;
 610     bib1.class = CLASS_DIAGSET;
 611     bib1.value = VAL_BIB1;
 612
 613     logf(LOG_DEBUG, "Diagnostic: %d -- %s", error, addinfo ? addinfo :
 614         "NULL");
 615     err = error;
 616     rec.which = Z_Records_NSD;
 617 #ifdef Z_95
 618     rec.u.nonSurrogateDiagnostic = &drec;
 619     drec.which = Z_DiagRec_defaultFormat;
 620     drec.u.defaultFormat = &dr;
 621 #else
 622     rec.u.nonSurrogateDiagnostic = &dr;
 623 #endif
 624     dr.diagnosticSetId = oid_getoidbyent(&bib1);
 625     dr.condition = &err;
 626     dr.which = Z_DiagForm_v2AddInfo;
 627     dr.addinfo = addinfo ? addinfo : "";
 628     return &rec;
 629 }
 630
 631 /*
 632  * surrogate diagnostic.
 633  */
 634 static Z_NamePlusRecord *surrogatediagrec(oid_proto proto, char *dbname,
 635                                             int error, char *addinfo)
 636 {
 637     static Z_NamePlusRecord rec;
 638     static int err;
 639     oident bib1;
 640 #ifdef Z_95
 641     static Z_DiagRec drec;
 642     static Z_DefaultDiagFormat dr;
 643 #else
 644     static Z_DiagRec dr;
 645 #endif
 646
 647     bib1.proto = proto;
 648     bib1.class = CLASS_DIAGSET;
 649     bib1.value = VAL_BIB1;
 650
 651     logf(LOG_DEBUG, "SurrogateDiagnotic: %d -- %s", error, addinfo);
 652     err = error;
 653     rec.databaseName = dbname;
 654     rec.which = Z_NamePlusRecord_surrogateDiagnostic;
 655 #ifdef Z_95
 656     rec.u.surrogateDiagnostic = &drec;
 657     drec.which = Z_DiagRec_defaultFormat;
 658     drec.u.defaultFormat = &dr;
 659 #else
 660     rec.u.surrogateDiagnostic = &dr;
 661 #endif
 662     dr.diagnosticSetId = oid_getoidbyent(&bib1);
 663     dr.condition = &err;
 664     dr.which = Z_DiagForm_v2AddInfo;
 665     dr.addinfo = addinfo ? addinfo : "";
 666     return &rec;
 667 }
 668
 669 /*
 670  * multiple nonsurrogate diagnostics.
 671  */
 672 static Z_DiagRecs *diagrecs(oid_proto proto, int error, char *addinfo)
 673 {
 674     static Z_DiagRecs recs;
 675     static int err;
 676     oident bib1;
 677 #ifdef Z_95
 678     static Z_DiagRec *recp[1], drec;
 679     static Z_DefaultDiagFormat rec;
 680 #else
 681     static Z_DiagRec *recp[1], rec;
 682 #endif
 683
 684     logf(LOG_DEBUG, "DiagRecs: %d -- %s", error, addinfo);
 685     bib1.proto = proto;
 686     bib1.class = CLASS_DIAGSET;
 687     bib1.value = VAL_BIB1;
 688
 689     err = error;
 690     recs.num_diagRecs = 1;
 691     recs.diagRecs = recp;
 692 #ifdef Z_95
 693     recp[0] = &drec;
 694     drec.which = Z_DiagRec_defaultFormat;
 695     drec.u.defaultFormat = &rec;
 696 #else
 697     recp[0] = &rec;
 698 #endif
 699     rec.diagnosticSetId = oid_getoidbyent(&bib1);
 700     rec.condition = &err;
 701     rec.which = Z_DiagForm_v2AddInfo;
 702     rec.addinfo = addinfo ? addinfo : "";
 703     return &recs;
 704 }
 705
 706 #define MAX_RECORDS 256
 707
 708 static Z_Records *pack_records(association *a, char *setname, int start,
 709                                 int *num, Z_ElementSetNames *esn,
 710                                 int *next, int *pres)
 711 {
 712     int recno, total_length = 0, toget = *num;
 713     static Z_Records records;
 714     static Z_NamePlusRecordList reclist;
 715     static Z_NamePlusRecord *list[MAX_RECORDS];
 716     oident recform;
 717     Odr_oid *oid;
 718
 719     records.which = Z_Records_DBOSD;
 720     records.u.databaseOrSurDiagnostics = &reclist;
 721     reclist.num_records = 0;
 722     reclist.records = list;
 723     *pres = Z_PRES_SUCCESS;
 724     *num = 0;
 725     *next = 0;
 726
 727     recform.proto = a->proto;
 728     recform.class = CLASS_RECSYN;
 729     recform.value = VAL_USMARC;
 730     if (!(oid = odr_oiddup(a->encode, oid_getoidbyent(&recform))))
 731         return 0;
 732
 733     logf(LOG_DEBUG, "Request to pack %d+%d", start, toget);
 734     logf(LOG_DEBUG, "pms=%d, mrs=%d", a->preferredMessageSize,
 735         a->maximumRecordSize);
 736     for (recno = start; reclist.num_records < toget; recno++)
 737     {
 738         bend_fetchrequest freq;
 739         bend_fetchresult *fres;
 740         Z_NamePlusRecord *thisrec;
 741         Z_DatabaseRecord *thisext;
 742
 743         if (reclist.num_records == MAX_RECORDS - 1)
 744         {
 745             *pres = Z_PRES_PARTIAL_2;
 746             break;
 747         }
 748         freq.setname = setname;
 749         freq.number = recno;
 750         if (!(fres = bend_fetch(a->backend, &freq, 0)))
 751         {
 752             *pres = Z_PRES_FAILURE;
 753             return diagrec(a->proto, 2, "Backend interface problem");
 754         }
 755         /* backend should be able to signal whether error is system-wide
 756            or only pertaining to current record */
 757         if (fres->errcode)
 758         {
 759             *pres = Z_PRES_FAILURE;
 760             return diagrec(a->proto, fres->errcode, fres->errstring);
 761         }
 762         logf(LOG_DEBUG, "  fetched record, len=%d, total=%d",
 763             fres->len, total_length);
 764         if (fres->len + total_length > a->preferredMessageSize)
 765         {
 766             /* record is small enough, really */
 767             if (fres->len <= a->preferredMessageSize)
 768             {
 769                 logf(LOG_DEBUG, "  Dropped last normal-sized record");
 770                 *pres = Z_PRES_PARTIAL_2;
 771                 break;
 772             }
 773             /* record can only be fetched by itself */
 774             if (fres->len < a->maximumRecordSize)
 775             {
 776                 logf(LOG_DEBUG, "  Record > prefmsgsz");
 777                 if (toget > 1)
 778                 {
 779                     logf(LOG_DEBUG, "  Dropped it");
 780                     reclist.records[reclist.num_records] =
 781                          surrogatediagrec(a->proto, fres->basename, 16, 0);
 782                     reclist.num_records++;
 783                     total_length += 10; /* totally arbitrary */
 784                     continue;
 785                 }
 786             }
 787             else /* too big entirely */
 788             {
 789                 logf(LOG_DEBUG, "Record > maxrcdsz");
 790                 reclist.records[reclist.num_records] =
 791                     surrogatediagrec(a->proto, fres->basename, 17, 0);
 792                 reclist.num_records++;
 793                 total_length += 10; /* totally arbitrary */
 794                 continue;
 795             }
 796         }
 797         if (!(thisrec = odr_malloc(a->encode, sizeof(*thisrec))))
 798             return 0;
 799         if (!(thisrec->databaseName = odr_malloc(a->encode,
 800             strlen(fres->basename) + 1)))
 801             return 0;
 802         strcpy(thisrec->databaseName, fres->basename);
 803         thisrec->which = Z_NamePlusRecord_databaseRecord;
 804         if (!(thisrec->u.databaseRecord = thisext = odr_malloc(a->encode,
 805             sizeof(Z_DatabaseRecord))))
 806             return 0;
 807         thisext->direct_reference = oid; /* should be OID for current MARC */
 808         thisext->indirect_reference = 0;
 809         thisext->descriptor = 0;
 810         thisext->which = ODR_EXTERNAL_octet;
 811         if (!(thisext->u.octet_aligned = odr_malloc(a->encode,
 812             sizeof(Odr_oct))))
 813             return 0;
 814         if (!(thisext->u.octet_aligned->buf = odr_malloc(a->encode, fres->len)))
 815             return 0;
 816         memcpy(thisext->u.octet_aligned->buf, fres->record, fres->len);
 817         thisext->u.octet_aligned->len = thisext->u.octet_aligned->size =
 818             fres->len;
 819         reclist.records[reclist.num_records] = thisrec;
 820         reclist.num_records++;
 821         total_length += fres->len;
 822         *next = fres->last_in_set ? 0 : recno + 1;
 823     }
 824     *num = reclist.num_records;
 825     return &records;
 826 }
 827
 828 static Z_APDU *process_searchRequest(association *assoc, request *reqb,
 829     int *fd)
 830 {
 831     Z_SearchRequest *req = reqb->request->u.searchRequest;
 832     bend_searchrequest bsrq;
 833     bend_searchresult *bsrt;
 834
 835     logf(LOG_LOG, "Got SearchRequest.");
 836
 837     bsrq.setname = req->resultSetName;
 838     bsrq.replace_set = *req->replaceIndicator;
 839     bsrq.num_bases = req->num_databaseNames;
 840     bsrq.basenames = req->databaseNames;
 841     bsrq.query = req->query;
 842
 843     if (!(bsrt = bend_search(assoc->backend, &bsrq, fd)))
 844         return 0;
 845     return response_searchRequest(assoc, reqb, bsrt, fd);
 846 }
 847
 848 bend_searchresult *bend_searchresponse(void *handle) {return 0;}
 849
 850 /*
 851  * Prepare a searchresponse based on the backend results. We probably want
 852  * to look at making the fetching of records nonblocking as well, but
 853  * so far, we'll keep things simple.
 854  * If bsrt is null, that means we're called in response to a communications
 855  * event, and we'll have to get the response for ourselves.
 856  */
 857 static Z_APDU *response_searchRequest(association *assoc, request *reqb,
 858     bend_searchresult *bsrt, int *fd)
 859 {
 860     Z_SearchRequest *req = reqb->request->u.searchRequest;
 861     static Z_APDU apdu;
 862     static Z_SearchResponse resp;
 863     static int nulint = 0;
 864     static bool_t sr = 1;
 865     static int next = 0;
 866     static int none = Z_RES_NONE;
 867
 868     apdu.which = Z_APDU_searchResponse;
 869     apdu.u.searchResponse = &resp;
 870     resp.referenceId = req->referenceId;
 871 #ifdef Z_95
 872     resp.additionalSearchInfo = 0;
 873     resp.otherInfo = 0;
 874 #endif
 875     *fd = -1;
 876     if (!bsrt && !(bsrt = bend_searchresponse(assoc->backend)))
 877     {
 878         logf(LOG_FATAL, "Bad result from backend");
 879         return 0;
 880     }
 881     else if (bsrt->errcode)
 882     {
 883         resp.records = diagrec(assoc->proto, bsrt->errcode,
 884             bsrt->errstring);
 885         resp.resultCount = &nulint;
 886         resp.numberOfRecordsReturned = &nulint;
 887         resp.nextResultSetPosition = &nulint;
 888         resp.searchStatus = &nulint;
 889         resp.resultSetStatus = &none;
 890         resp.presentStatus = 0;
 891     }
 892     else
 893     {
 894         int toget;
 895         Z_ElementSetNames *setnames;
 896         int presst = 0;
 897
 898         resp.records = 0;
 899         resp.resultCount = &bsrt->hits;
 900
 901         /* how many records does the user agent want, then? */
 902         if (bsrt->hits <= *req->smallSetUpperBound)
 903         {
 904             toget = bsrt->hits;
 905             setnames = req->smallSetElementSetNames;
 906         }
 907         else if (bsrt->hits < *req->largeSetLowerBound)
 908         {
 909             toget = *req->mediumSetPresentNumber;
 910             if (toget > bsrt->hits)
 911                 toget = bsrt->hits;
 912             setnames = req->mediumSetElementSetNames;
 913         }
 914         else
 915             toget = 0;
 916
 917         if (toget && !resp.records)
 918         {
 919             resp.records = pack_records(assoc, req->resultSetName, 1,
 920                 &toget, setnames, &next, &presst);
 921             if (!resp.records)
 922                 return 0;
 923             resp.numberOfRecordsReturned = &toget;
 924             resp.nextResultSetPosition = &next;
 925             resp.searchStatus = &sr;
 926             resp.resultSetStatus = 0;
 927             resp.presentStatus = &presst;
 928         }
 929         else
 930         {
 931             resp.numberOfRecordsReturned = &nulint;
 932             resp.nextResultSetPosition = &next;
 933             resp.searchStatus = &sr;
 934             resp.resultSetStatus = 0;
 935             resp.presentStatus = 0;
 936         }
 937     }
 938     return &apdu;
 939 }
 940
 941 /*
 942  * Maybe we got a little over-friendly when we designed bend_fetch to
 943  * get only one record at a time. Some backends can optimise multiple-record
 944  * fetches, and at any rate, there is some overhead involved in
 945  * all that selecting and hopping around. Problem is, of course, that the
 946  * frontend can't know ahead of time how many records it'll need to
 947  * fill the negotiated PDU size. Annoying. Segmentation or not, Z/SR
 948  * is downright lousy as a bulk data transfer protocol.
 949  *
 950  * To start with, we'll do the fetching of records from the backend
 951  * in one operation: To save some trips in and out of the event-handler,
 952  * and to simplify the interface to pack_records. At any rate, asynch
 953  * operation is more fun in operations that have an unpredictable execution
 954  * speed - which is normally more true for search than for present.
 955  */
 956 static Z_APDU *process_presentRequest(association *assoc, request *reqb,
 957     int *fd)
 958 {
 959     Z_PresentRequest *req = reqb->request->u.presentRequest;
 960     static Z_APDU apdu;
 961     static Z_PresentResponse resp;
 962     static int presst, next, num;
 963
 964     logf(LOG_LOG, "Got PresentRequest.");
 965     apdu.which = Z_APDU_presentResponse;
 966     apdu.u.presentResponse = &resp;
 967     resp.referenceId = req->referenceId;
 968 #ifdef Z_95
 969     resp.otherInfo = 0;
 970 #endif
 971
 972     num = *req->numberOfRecordsRequested;
 973     resp.records = pack_records(assoc, req->resultSetId,
 974         *req->resultSetStartPoint, &num, 0, &next, &presst);
 975     if (!resp.records)
 976         return 0;
 977     resp.numberOfRecordsReturned = &num;
 978     resp.presentStatus = &presst;
 979     resp.nextResultSetPosition = &next;
 980
 981     return &apdu;
 982 }
 983
 984 /*
 985  * Scan was implemented rather in a hurry, and with support for only the basic
 986  * elements of the service in the backend API. Suggestions are welcome.
 987  */
 988 static Z_APDU *process_scanRequest(association *assoc, request *reqb, int *fd)
 989 {
 990     Z_ScanRequest *req = reqb->request->u.scanRequest;
 991     static Z_APDU apdu;
 992     static Z_ScanResponse res;
 993     static int scanStatus = Z_Scan_failure;
 994     static int numberOfEntriesReturned = 0;
 995     oident *attent;
 996     static Z_ListEntries ents;
 997 #define SCAN_MAX_ENTRIES 200
 998     static Z_Entry *tab[SCAN_MAX_ENTRIES];
 999     bend_scanrequest srq;
1000     bend_scanresult *srs;
1001
1002     logf(LOG_LOG, "Got scanrequest");
1003     apdu.which = Z_APDU_scanResponse;
1004     apdu.u.scanResponse = &res;
1005     res.referenceId = req->referenceId;
1006     res.stepSize = 0;
1007     res.scanStatus = &scanStatus;
1008     res.numberOfEntriesReturned = &numberOfEntriesReturned;
1009     res.positionOfTerm = 0;
1010     res.entries = &ents;
1011     ents.which = Z_ListEntries_nonSurrogateDiagnostics;
1012     res.attributeSet = 0;
1013 #ifdef Z_95
1014     res.otherInfo = 0;
1015 #endif
1016
1017     if (req->attributeSet && (!(attent = oid_getentbyoid(req->attributeSet)) ||
1018         attent->class != CLASS_ATTSET || attent->value != VAL_BIB1))
1019         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 121, 0);
1020     else if (req->stepSize && *req->stepSize > 0)
1021         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 205, 0);
1022     else
1023     {
1024         if (req->termListAndStartPoint->term->which == Z_Term_general)
1025             logf(LOG_DEBUG, " term: '%.*s'",
1026                 req->termListAndStartPoint->term->u.general->len,
1027                 req->termListAndStartPoint->term->u.general->buf);
1028         srq.num_bases = req->num_databaseNames;
1029         srq.basenames = req->databaseNames;
1030         srq.num_entries = *req->numberOfTermsRequested;
1031         srq.term = req->termListAndStartPoint;
1032         srq.term_position = req->preferredPositionInResponse ?
1033             *req->preferredPositionInResponse : 1;
1034         if (!(srs = bend_scan(assoc->backend, &srq, 0)))
1035             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 2, 0);
1036         else if (srs->errcode)
1037             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto,
1038                 srs->errcode, srs->errstring);
1039         else
1040         {
1041             int i;
1042             static Z_Entries list;
1043
1044             if (srs->status == BEND_SCAN_PARTIAL)
1045                 scanStatus = Z_Scan_partial_5;
1046             else
1047                 scanStatus = Z_Scan_success;
1048             ents.which = Z_ListEntries_entries;
1049             ents.u.entries = &list;
1050             list.entries = tab;
1051             for (i = 0; i < srs->num_entries; i++)
1052             {
1053                 Z_Entry *e;
1054                 Z_TermInfo *t;
1055                 Odr_oct *o;
1056
1057                 if (i >= SCAN_MAX_ENTRIES)
1058                 {
1059                     scanStatus = Z_Scan_partial_4;
1060                     break;
1061                 }
1062                 list.entries[i] = e = odr_malloc(assoc->encode, sizeof(*e));
1063                 e->which = Z_Entry_termInfo;
1064                 e->u.termInfo = t = odr_malloc(assoc->encode, sizeof(*t));
1065                 t->suggestedAttributes = 0;
1066                 t->alternativeTerm = 0;
1067                 t->byAttributes = 0;
1068                 t->globalOccurrences = &srs->entries[i].occurrences;
1069                 t->term = odr_malloc(assoc->encode, sizeof(*t->term));
1070                 t->term->which = Z_Term_general;
1071                 t->term->u.general = o = odr_malloc(assoc->encode,
1072                     sizeof(Odr_oct));
1073                 o->buf = odr_malloc(assoc->encode, o->len = o->size =
1074                     strlen(srs->entries[i].term));
1075                 memcpy(o->buf, srs->entries[i].term, o->len);
1076                 logf(LOG_DEBUG, "  term #%d: '%s' (%d)", i,
1077                     srs->entries[i].term, srs->entries[i].occurrences);
1078             }
1079             list.num_entries = i;
1080             res.numberOfEntriesReturned = &list.num_entries;
1081             res.positionOfTerm = &srs->term_position;
1082         }
1083     }
1084
1085     return &apdu;
1086 }