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