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 1.31  1995-06-06 08:15:37  quinn
   8  * Cosmetic.
   9  *
  10  * Revision 1.30  1995/06/05  10:53:32  quinn
  11  * Added a better SCAN.
  12  *
  13  * Revision 1.29  1995/06/01  11:25:03  quinn
  14  * Smallish.
  15  *
  16  * Revision 1.28  1995/06/01  11:21:01  quinn
  17  * Attempting to fix a bug in pack-records. replaced break with continue
  18  * for large records, according to standard.
  19  *
  20  * Revision 1.27  1995/05/29  08:12:06  quinn
  21  * Moved oid to util
  22  *
  23  * Revision 1.26  1995/05/18  13:02:12  quinn
  24  * Smallish.
  25  *
  26  * Revision 1.25  1995/05/17  08:42:26  quinn
  27  * Transfer auth info to backend. Allow backend to reject init gracefully.
  28  *
  29  * Revision 1.24  1995/05/16  08:51:04  quinn
  30  * License, documentation, and memory fixes
  31  *
  32  * Revision 1.23  1995/05/15  13:25:10  quinn
  33  * Fixed memory bug.
  34  *
  35  * Revision 1.22  1995/05/15  11:56:39  quinn
  36  * Asynchronous facilities. Restructuring of seshigh code.
  37  *
  38  * Revision 1.21  1995/05/02  08:53:19  quinn
  39  * Trying in vain to fix comm with ISODE
  40  *
  41  * Revision 1.20  1995/04/20  15:13:00  quinn
  42  * Cosmetic
  43  *
  44  * Revision 1.19  1995/04/18  08:15:34  quinn
  45  * Added dynamic memory allocation on encoding (whew). Code is now somewhat
  46  * neater. We'll make the same change for decoding one day.
  47  *
  48  * Revision 1.18  1995/04/17  11:28:25  quinn
  49  * Smallish
  50  *
  51  * Revision 1.17  1995/04/10  10:23:36  quinn
  52  * Some work to add scan and other things.
  53  *
  54  * Revision 1.16  1995/03/31  09:18:55  quinn
  55  * Added logging.
  56  *
  57  * Revision 1.15  1995/03/30  14:03:23  quinn
  58  * Added RFC1006 as separate library
  59  *
  60  * Revision 1.14  1995/03/30  12:18:17  quinn
  61  * Fixed bug.
  62  *
  63  * Revision 1.13  1995/03/30  09:09:24  quinn
  64  * Added state-handle and some support for asynchronous activities.
  65  *
  66  * Revision 1.12  1995/03/29  15:40:16  quinn
  67  * Ongoing work. Statserv is now dynamic by default
  68  *
  69  * Revision 1.11  1995/03/28  09:16:21  quinn
  70  * Added record packing to the search request
  71  *
  72  * Revision 1.10  1995/03/27  08:34:24  quinn
  73  * Added dynamic server functionality.
  74  * Released bindings to session.c (is now redundant)
  75  *
  76  * Revision 1.9  1995/03/22  15:01:26  quinn
  77  * Adjusting record packing.
  78  *
  79  * Revision 1.8  1995/03/22  10:13:21  quinn
  80  * Working on record packer
  81  *
  82  * Revision 1.7  1995/03/21  15:53:31  quinn
  83  * Little changes.
  84  *
  85  * Revision 1.6  1995/03/21  12:30:09  quinn
  86  * Beginning to add support for record packing.
  87  *
  88  * Revision 1.5  1995/03/17  10:44:13  quinn
  89  * Added catch of null-string in makediagrec
  90  *
  91  * Revision 1.4  1995/03/17  10:18:08  quinn
  92  * Added memory management.
  93  *
  94  * Revision 1.3  1995/03/16  17:42:39  quinn
  95  * Little changes
  96  *
  97  * Revision 1.2  1995/03/16  13:29:01  quinn
  98  * Partitioned server.
  99  *
 100  * Revision 1.1  1995/03/15  16:02:10  quinn
 101  * Modded session.c to seshigh.c
 102  *
 103  */
 104
 105 /*
 106  * Frontend server logic.
 107  *
 108  * This code receives incoming APDUs, and handles client requests by means
 109  * of the backend API.
 110  *
 111  * Some of the code is getting quite involved, compared to simpler servers -
 112  * primarily because it is asynchronous both in the communication with
 113  * the user and the backend. We think the complexity will pay off in
 114  * the form of greater flexibility when more asynchronous facilities
 115  * are implemented.
 116  *
 117  * Memory management has become somewhat involved. In the simple case, where
 118  * only one PDU is pending at a time, it will simply reuse the same memory,
 119  * once it has found its working size. When we enable multiple concurrent
 120  * operations, perhaps even with multiple parallel calls to the backend, it
 121  * will maintain a pool of buffers for encoding and decoding, trying to
 122  * minimize memory allocation/deallocation during normal operation.
 123  *
 124  * TODOs include (and will be done in order of public interest):
 125  *
 126  * Support for EXPLAIN - provide simple meta-database system.
 127  * Support for access control.
 128  * Support for resource control.
 129  * Support for extended services - primarily Item Order.
 130  * Rest of Z39.50-1994
 131  *
 132  */
 133
 134 #include <stdlib.h>
 135 #include <stdio.h>
 136 #include <unistd.h>
 137 #include <assert.h>
 138
 139 #include <dmalloc.h>
 140 #include <comstack.h>
 141 #include <eventl.h>
 142 #include <session.h>
 143 #include <proto.h>
 144 #include <oid.h>
 145 #include <log.h>
 146 #include <statserv.h>
 147 #include "../version.h"
 148
 149 #include <backend.h>
 150
 151 static int process_request(association *assoc);
 152 void backend_response(IOCHAN i, int event);
 153 static int process_response(association *assoc, request *req, Z_APDU *res);
 154 static Z_APDU *process_initRequest(association *assoc, request *reqb);
 155 static Z_APDU *process_searchRequest(association *assoc, request *reqb,
 156     int *fd);
 157 static Z_APDU *response_searchRequest(association *assoc, request *reqb,
 158     bend_searchresult *bsrt, int *fd);
 159 static Z_APDU *process_presentRequest(association *assoc, request *reqb,
 160     int *fd);
 161 static Z_APDU *process_scanRequest(association *assoc, request *reqb, int *fd);
 162
 163 static FILE *apduf = 0; /* for use in static mode */
 164 static statserv_options_block *control_block = 0;
 165
 166 /*
 167  * Create and initialize a new association-handle.
 168  *  channel  : iochannel for the current line.
 169  *  link     : communications channel.
 170  * Returns: 0 or a new association handle.
 171  */
 172 association *create_association(IOCHAN channel, COMSTACK link)
 173 {
 174     association *new;
 175
 176     if (!control_block)
 177         control_block = statserv_getcontrol();
 178     if (!(new = malloc(sizeof(*new))))
 179         return 0;
 180     new->client_chan = channel;
 181     new->client_link = link;
 182     if (!(new->decode = odr_createmem(ODR_DECODE)) ||
 183         !(new->encode = odr_createmem(ODR_ENCODE)))
 184         return 0;
 185     if (*control_block->apdufile)
 186     {
 187         char filename[256];
 188         FILE *f;
 189
 190         strcpy(filename, control_block->apdufile);
 191         if (!(new->print = odr_createmem(ODR_PRINT)))
 192             return 0;
 193         if (*control_block->apdufile != '-')
 194         {
 195             strcpy(filename, control_block->apdufile);
 196             if (!control_block->dynamic)
 197             {
 198                 if (!apduf)
 199                 {
 200                     if (!(apduf = fopen(filename, "w")))
 201                     {
 202                         logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 203                         return 0;
 204                     }
 205                     setvbuf(apduf, 0, _IONBF, 0);
 206                 }
 207                 f = apduf;
 208             }
 209             else
 210             {
 211                 sprintf(filename + strlen(filename), ".%d", getpid());
 212                 if (!(f = fopen(filename, "w")))
 213                 {
 214                     logf(LOG_WARN|LOG_ERRNO, "%s", filename);
 215                     return 0;
 216                 }
 217                 setvbuf(f, 0, _IONBF, 0);
 218             }
 219             odr_setprint(new->print, f);
 220         }
 221     }
 222     else
 223         new->print = 0;
 224     new->input_buffer = 0;
 225     new->input_buffer_len = 0;
 226     new->backend = 0;
 227     new->rejected = 0;
 228     request_initq(&new->incoming);
 229     request_initq(&new->outgoing);
 230     new->proto = cs_getproto(link);
 231     return new;
 232 }
 233
 234 /*
 235  * Free association and release resources.
 236  */
 237 void destroy_association(association *h)
 238 {
 239     odr_destroy(h->decode);
 240     odr_destroy(h->encode);
 241     if (h->print)
 242         odr_destroy(h->print);
 243     if (h->input_buffer)
 244         free(h->input_buffer);
 245     if (h->backend)
 246         bend_close(h->backend);
 247     while (request_deq(&h->incoming));
 248     while (request_deq(&h->outgoing));
 249     free(h);
 250 }
 251
 252 /*
 253  * This is where PDUs from the client are read and the further
 254  * processing is initiated. Flow of control moves down through the
 255  * various process_* functions below, until the encoded result comes back up
 256  * to the output handler in here.
 257  *
 258  *  h     : the I/O channel that has an outstanding event.
 259  *  event : the current outstanding event.
 260  */
 261 void ir_session(IOCHAN h, int event)
 262 {
 263     int res;
 264     association *assoc = iochan_getdata(h);
 265     COMSTACK conn = assoc->client_link;
 266     request *req;
 267
 268     assert(h && conn && assoc);
 269     if (event & EVENT_INPUT || event & EVENT_WORK) /* input */
 270     {
 271         if (event & EVENT_INPUT)
 272         {
 273             logf(LOG_DEBUG, "ir_session (input)");
 274             assert(assoc && conn);
 275             /* We aren't speaking to this fellow */
 276             if (assoc->rejected)
 277             {
 278                 logf(LOG_LOG, "Closed connection after reject");
 279                 cs_close(conn);
 280                 destroy_association(assoc);
 281                 iochan_destroy(h);
 282                 return;
 283             }
 284             if ((res = cs_get(conn, &assoc->input_buffer,
 285                 &assoc->input_buffer_len)) <= 0)
 286             {
 287                 logf(LOG_LOG, "Connection closed by client");
 288                 cs_close(conn);
 289                 destroy_association(assoc);
 290                 iochan_destroy(h);
 291                 return;
 292             }
 293             else if (res == 1) /* incomplete read - wait for more  */
 294                 return;
 295             if (cs_more(conn)) /* more stuff - call us again later, please */
 296                 iochan_setevent(h, EVENT_INPUT);
 297
 298             /* we got a complete PDU. Let's decode it */
 299             logf(LOG_DEBUG, "Got PDU, %d bytes", res);
 300             req = request_get(); /* get a new request structure */
 301             odr_reset(assoc->decode);
 302             odr_setbuf(assoc->decode, assoc->input_buffer, res, 0);
 303             if (!z_APDU(assoc->decode, &req->request, 0))
 304             {
 305                 logf(LOG_WARN, "ODR error: %s",
 306                     odr_errlist[odr_geterror(assoc->decode)]);
 307                 cs_close(conn);
 308                 destroy_association(assoc);
 309                 iochan_destroy(h);
 310                 return;
 311             }
 312             req->request_mem = odr_extract_mem(assoc->decode);
 313             if (assoc->print && !z_APDU(assoc->print, &req->request, 0))
 314             {
 315                 logf(LOG_WARN, "ODR print error: %s",
 316                     odr_errlist[odr_geterror(assoc->print)]);
 317                 odr_reset(assoc->print);
 318             }
 319             request_enq(&assoc->incoming, req);
 320         }
 321
 322         /* can we do something yet? */
 323         req = request_head(&assoc->incoming);
 324         if (req->state == REQUEST_IDLE)
 325             if (process_request(assoc) < 0)
 326             {
 327                 cs_close(conn);
 328                 destroy_association(assoc);
 329                 iochan_destroy(h);
 330             }
 331     }
 332     if (event & EVENT_OUTPUT)
 333     {
 334         request *req = request_head(&assoc->outgoing);
 335
 336         logf(LOG_DEBUG, "ir_session (output)");
 337         req->state = REQUEST_PENDING;
 338         switch (res = cs_put(conn, req->response, req->len_response))
 339         {
 340             case -1:
 341                 logf(LOG_LOG, "Connection closed by client");
 342                 cs_close(conn);
 343                 destroy_association(assoc);
 344                 iochan_destroy(h);
 345                 break;
 346             case 0: /* all sent - release the request structure */
 347                 logf(LOG_DEBUG, "Wrote PDU, %d bytes", req->len_response);
 348                 odr_release_mem(req->request_mem);
 349                 request_deq(&assoc->outgoing);
 350                 request_release(req);
 351                 if (!request_head(&assoc->outgoing))
 352                     iochan_clearflag(h, EVENT_OUTPUT);
 353                 break;
 354             /* value of 1 -- partial send -- is simply ignored */
 355         }
 356     }
 357     if (event & EVENT_EXCEPT)
 358     {
 359         logf(LOG_DEBUG, "ir_session (exception)");
 360         cs_close(conn);
 361         destroy_association(assoc);
 362         iochan_destroy(h);
 363     }
 364 }
 365
 366 /*
 367  * Initiate request processing.
 368  */
 369 static int process_request(association *assoc)
 370 {
 371     request *req = request_head(&assoc->incoming);
 372     int fd = -1;
 373     Z_APDU *res;
 374
 375     logf(LOG_DEBUG, "process_request");
 376     assert(req && req->state == REQUEST_IDLE);
 377     switch (req->request->which)
 378     {
 379         case Z_APDU_initRequest:
 380             res = process_initRequest(assoc, req); break;
 381         case Z_APDU_searchRequest:
 382             res = process_searchRequest(assoc, req, &fd); break;
 383         case Z_APDU_presentRequest:
 384             res = process_presentRequest(assoc, req, &fd); break;
 385         case Z_APDU_scanRequest:
 386             res = process_scanRequest(assoc, req, &fd); break;
 387         default:
 388             logf(LOG_WARN, "Bad APDU received");
 389             return -1;
 390     }
 391     if (res)
 392     {
 393         logf(LOG_DEBUG, "  result immediately available");
 394         return process_response(assoc, req, res);
 395     }
 396     else if (fd < 0)
 397     {
 398         logf(LOG_WARN, "   bad result");
 399         return -1;
 400     }
 401     else /* no result yet - one will be provided later */
 402     {
 403         IOCHAN chan;
 404
 405         /* Set up an I/O handler for the fd supplied by the backend */
 406
 407         logf(LOG_DEBUG, "   establishing handler for result");
 408         req->state = REQUEST_PENDING;
 409         if (!(chan = iochan_create(fd, backend_response, EVENT_INPUT)))
 410             abort();
 411         iochan_setdata(chan, assoc);
 412         return 0;
 413     }
 414 }
 415
 416 /*
 417  * Handle message from the backend.
 418  */
 419 void backend_response(IOCHAN i, int event)
 420 {
 421     association *assoc = iochan_getdata(i);
 422     request *req = request_head(&assoc->incoming);
 423     Z_APDU *res;
 424     int fd;
 425
 426     logf(LOG_DEBUG, "backend_response");
 427     assert(assoc && req && req->state != REQUEST_IDLE);
 428     /* determine what it is we're waiting for */
 429     switch (req->request->which)
 430     {
 431         case Z_APDU_searchRequest:
 432             res = response_searchRequest(assoc, req, 0, &fd); break;
 433 #if 0
 434         case Z_APDU_presentRequest:
 435             res = response_presentRequest(assoc, req, 0, &fd); break;
 436         case Z_APDU_scanRequest:
 437             res = response_scanRequest(assoc, req, 0, &fd); break;
 438 #endif
 439         default:
 440             logf(LOG_WARN, "Serious programmer's lapse or bug");
 441             abort();
 442     }
 443     if ((res && process_response(assoc, req, res) < 0) || fd < 0)
 444     {
 445         logf(LOG_LOG, "Fatal error when talking to backend");
 446         cs_close(assoc->client_link);
 447         destroy_association(assoc);
 448         iochan_destroy(assoc->client_chan);
 449         iochan_destroy(i);
 450         return;
 451     }
 452     else if (!res) /* no result yet - try again later */
 453     {
 454         logf(LOG_DEBUG, "   no result yet");
 455         iochan_setfd(i, fd); /* in case fd has changed */
 456     }
 457 }
 458
 459 /*
 460  * Encode response, and transfer the request structure to the outgoing queue.
 461  */
 462 static int process_response(association *assoc, request *req, Z_APDU *res)
 463 {
 464     odr_setbuf(assoc->encode, req->response, req->size_response, 1);
 465     if (!z_APDU(assoc->encode, &res, 0))
 466     {
 467         logf(LOG_WARN, "ODR error when encoding response: %s",
 468             odr_errlist[odr_geterror(assoc->decode)]);
 469         return -1;
 470     }
 471     req->response = odr_getbuf(assoc->encode, &req->len_response,
 472         &req->size_response);
 473     odr_setbuf(assoc->encode, 0, 0, 0); /* don't free if we abort later */
 474     odr_reset(assoc->encode);
 475     if (assoc->print && !z_APDU(assoc->print, &res, 0))
 476     {
 477         logf(LOG_WARN, "ODR print error: %s",
 478             odr_errlist[odr_geterror(assoc->print)]);
 479         odr_reset(assoc->print);
 480     }
 481     /* change this when we make the backend reentrant */
 482     assert(req == request_head(&assoc->incoming));
 483     req->state = REQUEST_IDLE;
 484     request_deq(&assoc->incoming);
 485     request_enq(&assoc->outgoing, req);
 486     /* turn the work over to the ir_session handler */
 487     iochan_setflag(assoc->client_chan, EVENT_OUTPUT);
 488     /* Is there more work to be done? give that to the input handler too */
 489     if (request_head(&assoc->incoming))
 490         iochan_setevent(assoc->client_chan, EVENT_WORK);
 491     return 0;
 492 }
 493
 494 /*
 495  * Handle init request.
 496  * At the moment, we don't check the protocol version or the options
 497  * anywhere else in the code - we just try not to do anything that would
 498  * break a naive client. We'll toss 'em into the association block when
 499  * we need them there.
 500  */
 501 static Z_APDU *process_initRequest(association *assoc, request *reqb)
 502 {
 503     Z_InitRequest *req = reqb->request->u.initRequest;
 504     Z_APDU *apdu = zget_APDU(assoc->encode, Z_APDU_initResponse);
 505     Z_InitResponse *resp = apdu->u.initResponse;
 506     bend_initrequest binitreq;
 507     bend_initresult *binitres;
 508
 509     logf(LOG_LOG, "Got initRequest");
 510     if (req->implementationId)
 511         logf(LOG_LOG, "Id:        %s", req->implementationId);
 512     if (req->implementationName)
 513         logf(LOG_LOG, "Name:      %s", req->implementationName);
 514     if (req->implementationVersion)
 515         logf(LOG_LOG, "Version:   %s", req->implementationVersion);
 516
 517     binitreq.configname = "default-config";
 518     binitreq.auth = req->idAuthentication;
 519     if (!(binitres = bend_init(&binitreq)))
 520     {
 521         logf(LOG_WARN, "Bad response from backend.");
 522         return 0;
 523     }
 524
 525     assoc->backend = binitres->handle;
 526     resp->referenceId = req->referenceId;
 527     /* let's tell the client what we can do */
 528     if (ODR_MASK_GET(req->options, Z_Options_search))
 529         ODR_MASK_SET(resp->options, Z_Options_search);
 530     if (ODR_MASK_GET(req->options, Z_Options_present))
 531         ODR_MASK_SET(resp->options, Z_Options_present);
 532 #if 0
 533     if (ODR_MASK_GET(req->options, Z_Options_delSet))
 534         ODR_MASK_SET(&options, Z_Options_delSet);
 535 #endif
 536     if (ODR_MASK_GET(req->options, Z_Options_namedResultSets))
 537         ODR_MASK_SET(resp->options, Z_Options_namedResultSets);
 538     if (ODR_MASK_GET(req->options, Z_Options_scan))
 539         ODR_MASK_SET(resp->options, Z_Options_scan);
 540     if (ODR_MASK_GET(req->options, Z_Options_concurrentOperations))
 541         ODR_MASK_SET(resp->options, Z_Options_concurrentOperations);
 542
 543     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_1))
 544         ODR_MASK_SET(resp->protocolVersion, Z_ProtocolVersion_1);
 545     if (ODR_MASK_GET(req->protocolVersion, Z_ProtocolVersion_2))
 546         ODR_MASK_SET(resp->protocolVersion, Z_ProtocolVersion_2);
 547     assoc->maximumRecordSize = *req->maximumRecordSize;
 548     if (assoc->maximumRecordSize > control_block->maxrecordsize)
 549         assoc->maximumRecordSize = control_block->maxrecordsize;
 550     assoc->preferredMessageSize = *req->preferredMessageSize;
 551     if (assoc->preferredMessageSize > assoc->maximumRecordSize)
 552         assoc->preferredMessageSize = assoc->maximumRecordSize;
 553     resp->preferredMessageSize = &assoc->preferredMessageSize;
 554     resp->maximumRecordSize = &assoc->maximumRecordSize;
 555     resp->implementationName = "Index Data/YAZ Generic Frontend Server";
 556     if (binitres->errcode)
 557     {
 558         logf(LOG_LOG, "Connection rejected by backend.");
 559         *resp->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     logf(LOG_LOG, "Got scanrequest");
 935     apdu.which = Z_APDU_scanResponse;
 936     apdu.u.scanResponse = &res;
 937     res.referenceId = req->referenceId;
 938     res.stepSize = 0;
 939     res.scanStatus = &scanStatus;
 940     res.numberOfEntriesReturned = &numberOfEntriesReturned;
 941     res.positionOfTerm = 0;
 942     res.entries = &ents;
 943     ents.which = Z_ListEntries_nonSurrogateDiagnostics;
 944     res.attributeSet = 0;
 945
 946     if (req->attributeSet && (!(attent = oid_getentbyoid(req->attributeSet)) ||
 947         attent->class != CLASS_ATTSET || attent->value != VAL_BIB1))
 948         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 121, 0);
 949     else if (req->stepSize && *req->stepSize > 0)
 950         ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 205, 0);
 951     else
 952     {
 953         srq.num_bases = req->num_databaseNames;
 954         srq.basenames = req->databaseNames;
 955         srq.num_entries = *req->numberOfTermsRequested;
 956         srq.term = req->termListAndStartPoint;
 957         srq.term_position = req->preferredPositionInResponse ?
 958             *req->preferredPositionInResponse : 1;
 959         if (req->termListAndStartPoint->term->which == Z_Term_general)
 960             logf(LOG_DEBUG, "  term: %.*s",
 961                 req->termListAndStartPoint->term->u.general->len,
 962                 req->termListAndStartPoint->term->u.general->buf);
 963         if (!(srs = bend_scan(assoc->backend, &srq, 0)))
 964             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto, 2, 0);
 965         else if (srs->errcode)
 966             ents.u.nonSurrogateDiagnostics = diagrecs(assoc->proto,
 967                 srs->errcode, srs->errstring);
 968         else
 969         {
 970             int i;
 971             static Z_Entries list;
 972
 973             if (srs->status == BEND_SCAN_PARTIAL)
 974                 scanStatus = Z_Scan_partial_5;
 975             else
 976                 scanStatus = Z_Scan_success;
 977             ents.which = Z_ListEntries_entries;
 978             ents.u.entries = &list;
 979             list.entries = tab;
 980             for (i = 0; i < srs->num_entries; i++)
 981             {
 982                 Z_Entry *e;
 983                 Z_TermInfo *t;
 984                 Odr_oct *o;
 985
 986                 if (i >= SCAN_MAX_ENTRIES)
 987                 {
 988                     scanStatus = Z_Scan_partial_4;
 989                     break;
 990                 }
 991                 list.entries[i] = e = odr_malloc(assoc->encode, sizeof(*e));
 992                 e->which = Z_Entry_termInfo;
 993                 e->u.termInfo = t = odr_malloc(assoc->encode, sizeof(*t));
 994                 t->suggestedAttributes = 0;
 995                 t->alternativeTerm = 0;
 996                 t->byAttributes = 0;
 997                 t->globalOccurrences = &srs->entries[i].occurrences;
 998                 t->term = odr_malloc(assoc->encode, sizeof(*t->term));
 999                 t->term->which = Z_Term_general;
1000                 t->term->u.general = o = odr_malloc(assoc->encode,
1001                     sizeof(Odr_oct));
1002                 o->buf = odr_malloc(assoc->encode, o->len = o->size =
1003                     strlen(srs->entries[i].term));
1004                 memcpy(o->buf, srs->entries[i].term, o->len);
1005             }
1006             list.num_entries = i;
1007             res.numberOfEntriesReturned = &list.num_entries;
1008             res.positionOfTerm = &srs->term_position;
1009         }
1010     }
1011
1012     return &apdu;
1013 }