src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) 2006-2011 Index Data
   3
   4 Pazpar2 is free software; you can redistribute it and/or modify it under
   5 the terms of the GNU General Public License as published by the Free
   6 Software Foundation; either version 2, or (at your option) any later
   7 version.
   8
   9 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
  10 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17
  18 */
  19
  20 /** \file connection.c
  21     \brief Z39.50 connection (low-level client)
  22 */
  23
  24 #if HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #if HAVE_SYS_TIME_H
  32 #include <sys/time.h>
  33 #endif
  34 #if HAVE_UNISTD_H
  35 #include <unistd.h>
  36 #endif
  37
  38 #include <signal.h>
  39 #include <assert.h>
  40
  41 #include <yaz/log.h>
  42 #include <yaz/comstack.h>
  43 #include <yaz/tcpip.h>
  44 #include "connection.h"
  45 #include "session.h"
  46 #include "host.h"
  47 #include "client.h"
  48 #include "settings.h"
  49
  50 /* connection counting (1) , disable connection counting (0) */
  51 #if 1
  52 static YAZ_MUTEX g_mutex = 0;
  53 static int no_connections = 0;
  54 static int total_no_connections = 0;
  55
  56 static int connection_use(int delta)
  57 {
  58     int result;
  59     if (!g_mutex)
  60         yaz_mutex_create(&g_mutex);
  61     yaz_mutex_enter(g_mutex);
  62     no_connections += delta;
  63     result = no_connections;
  64     if (delta > 0)
  65         total_no_connections += delta;
  66     yaz_mutex_leave(g_mutex);
  67     if (delta == 0)
  68             return result;
  69     yaz_log(YLOG_LOG, "%s connections=%d", delta > 0 ? "INC" : "DEC",
  70             no_connections);
  71     return result;
  72 }
  73
  74 int connections_count(void)
  75 {
  76     return connection_use(0);
  77 }
  78
  79
  80 #else
  81 #define connection_use(x)
  82 #define connections_count(x) 0
  83 #define connections_count_total(x) 0
  84 #endif
  85
  86
  87 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  88  */
  89 struct connection {
  90     IOCHAN iochan;
  91     ZOOM_connection link;
  92     struct host *host;
  93     struct client *client;
  94     char *zproxy;
  95     enum {
  96         Conn_Closed,
  97         Conn_Connecting,
  98         Conn_Open
  99     } state;
 100     int operation_timeout;
 101     int session_timeout;
 102     struct connection *next; // next for same host or next in free list
 103 };
 104
 105 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
 106
 107 static int connection_is_idle(struct connection *co)
 108 {
 109     ZOOM_connection link = co->link;
 110     int event;
 111
 112     if (co->state != Conn_Open || !link)
 113         return 0;
 114
 115     if (!ZOOM_connection_is_idle(link))
 116         return 0;
 117     event = ZOOM_connection_peek_event(link);
 118     if (event == ZOOM_EVENT_NONE)
 119         return 1;
 120     else
 121         return 0;
 122 }
 123
 124 ZOOM_connection connection_get_link(struct connection *co)
 125 {
 126     return co->link;
 127 }
 128
 129 static void remove_connection_from_host(struct connection *con)
 130 {
 131     struct connection **conp = &con->host->connections;
 132     assert(con);
 133     while (*conp)
 134     {
 135         if (*conp == con)
 136         {
 137             *conp = (*conp)->next;
 138             break;
 139         }
 140         conp = &(*conp)->next;
 141     }
 142     yaz_cond_broadcast(con->host->cond_ready);
 143 }
 144
 145 // Close connection and recycle structure
 146 static void connection_destroy(struct connection *co)
 147 {
 148     if (co->link)
 149     {
 150         ZOOM_connection_destroy(co->link);
 151         iochan_destroy(co->iochan);
 152     }
 153     yaz_log(YLOG_DEBUG, "%p Connection destroy %s", co, co->host->url);
 154
 155     if (co->client)
 156     {
 157         client_disconnect(co->client);
 158     }
 159
 160     xfree(co->zproxy);
 161     xfree(co);
 162     connection_use(-1);
 163 }
 164
 165 // Creates a new connection for client, associated with the host of
 166 // client's database
 167 static struct connection *connection_create(struct client *cl,
 168                                             struct host *host,
 169                                             int operation_timeout,
 170                                             int session_timeout,
 171                                             iochan_man_t iochan_man)
 172 {
 173     struct connection *co;
 174
 175     co = xmalloc(sizeof(*co));
 176     co->host = host;
 177
 178     co->client = cl;
 179     co->zproxy = 0;
 180     client_set_connection(cl, co);
 181     co->link = 0;
 182     co->state = Conn_Closed;
 183     co->operation_timeout = operation_timeout;
 184     co->session_timeout = session_timeout;
 185
 186     if (host->ipport)
 187         connection_connect(co, iochan_man);
 188
 189     yaz_mutex_enter(host->mutex);
 190     co->next = co->host->connections;
 191     co->host->connections = co;
 192     yaz_mutex_leave(host->mutex);
 193
 194     connection_use(1);
 195     return co;
 196 }
 197
 198 static void non_block_events(struct connection *co)
 199 {
 200     int got_records = 0;
 201     IOCHAN iochan = co->iochan;
 202     ZOOM_connection link = co->link;
 203     while (1)
 204     {
 205         struct client *cl = co->client;
 206         int ev;
 207         int r = ZOOM_event_nonblock(1, &link);
 208         if (!r)
 209             break;
 210         if (!cl)
 211             continue;
 212         ev = ZOOM_connection_last_event(link);
 213
 214 #if 1
 215         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 216 #endif
 217         switch (ev)
 218         {
 219         case ZOOM_EVENT_END:
 220             {
 221                 const char *error, *addinfo;
 222                 int err;
 223                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 224                 {
 225                     yaz_log(YLOG_LOG, "Error %s from %s",
 226                             error, client_get_id(cl));
 227                     client_set_diagnostic(cl, err);
 228                     client_set_state(cl, Client_Error);
 229                 }
 230                 else
 231                 {
 232                     iochan_settimeout(iochan, co->session_timeout);
 233                     client_set_state(cl, Client_Idle);
 234                 }
 235                 yaz_cond_broadcast(co->host->cond_ready);
 236             }
 237             break;
 238         case ZOOM_EVENT_SEND_DATA:
 239             break;
 240         case ZOOM_EVENT_RECV_DATA:
 241             break;
 242         case ZOOM_EVENT_UNKNOWN:
 243             break;
 244         case ZOOM_EVENT_SEND_APDU:
 245             client_set_state(co->client, Client_Working);
 246             iochan_settimeout(iochan, co->operation_timeout);
 247             break;
 248         case ZOOM_EVENT_RECV_APDU:
 249             break;
 250         case ZOOM_EVENT_CONNECT:
 251             yaz_log(YLOG_LOG, "Connected to %s", client_get_id(cl));
 252             co->state = Conn_Open;
 253             break;
 254         case ZOOM_EVENT_RECV_SEARCH:
 255             client_search_response(cl);
 256             break;
 257         case ZOOM_EVENT_RECV_RECORD:
 258             client_record_response(cl);
 259             got_records = 1;
 260             break;
 261         default:
 262             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 263                     ev, client_get_id(cl));
 264         }
 265     }
 266     if (got_records)
 267     {
 268         struct client *cl = co->client;
 269         if (cl)
 270         {
 271             client_check_preferred_watch(cl);
 272             client_got_records(cl);
 273         }
 274     }
 275 }
 276
 277 void connection_continue(struct connection *co)
 278 {
 279     int r = ZOOM_connection_exec_task(co->link);
 280     if (!r)
 281     {
 282         const char *error, *addinfo;
 283         int err;
 284         if ((err = ZOOM_connection_error(co->link, &error, &addinfo)))
 285         {
 286             if (co->client)
 287             {
 288                 yaz_log(YLOG_LOG, "Error %s from %s",
 289                         error, client_get_id(co->client));
 290                 client_set_diagnostic(co->client, err);
 291                 client_set_state_nb(co->client, Client_Error);
 292             }
 293         }
 294     }
 295     else
 296     {
 297         iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 298         iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 299     }
 300 }
 301
 302 static void connection_handler(IOCHAN iochan, int event)
 303 {
 304     struct connection *co = iochan_getdata(iochan);
 305     struct client *cl;
 306     struct host *host = co->host;
 307
 308     yaz_mutex_enter(host->mutex);
 309     cl = co->client;
 310     if (!cl)
 311     {
 312         /* no client associated with it.. We are probably getting
 313            a closed connection from the target.. Or, perhaps, an unexpected
 314            package.. We will just close the connection */
 315         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 316         remove_connection_from_host(co);
 317         yaz_mutex_leave(host->mutex);
 318         connection_destroy(co);
 319     }
 320     else if (event & EVENT_TIMEOUT)
 321     {
 322         if (co->state == Conn_Connecting)
 323         {
 324             yaz_log(YLOG_WARN, "%p connect timeout %s", co, client_get_id(cl));
 325
 326             client_set_state(cl, Client_Error);
 327             remove_connection_from_host(co);
 328             yaz_mutex_leave(host->mutex);
 329             connection_destroy(co);
 330         }
 331         else
 332         {
 333             yaz_log(YLOG_LOG,  "%p Connection idle timeout %s", co, client_get_id(cl));
 334             remove_connection_from_host(co);
 335             yaz_mutex_leave(host->mutex);
 336             connection_destroy(co);
 337         }
 338     }
 339     else
 340     {
 341         yaz_mutex_leave(host->mutex);
 342
 343         client_lock(cl);
 344         non_block_events(co);
 345
 346         ZOOM_connection_fire_event_socket(co->link, event);
 347
 348         non_block_events(co);
 349         client_unlock(cl);
 350
 351         if (co->link)
 352         {
 353             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 354             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 355         }
 356     }
 357 }
 358
 359
 360 // Disassociate connection from client
 361 static void connection_release(struct connection *co)
 362 {
 363     struct client *cl = co->client;
 364
 365     if (!cl)
 366         return;
 367     client_set_connection(cl, 0);
 368     co->client = 0;
 369 }
 370
 371 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 372 {
 373     struct connection *con;
 374
 375 start:
 376     yaz_mutex_enter(host->mutex);
 377     con = host->connections;
 378     while (con)
 379     {
 380         if (con->state == Conn_Closed)
 381         {
 382             if (!host->ipport) /* unresolved */
 383             {
 384                 remove_connection_from_host(con);
 385                 yaz_mutex_leave(host->mutex);
 386                 connection_destroy(con);
 387                 goto start;
 388                 /* start all over .. at some point it will be NULL */
 389             }
 390             else if (!con->client)
 391             {
 392                 remove_connection_from_host(con);
 393                 yaz_mutex_leave(host->mutex);
 394                 connection_destroy(con);
 395                 /* start all over .. at some point it will be NULL */
 396                 goto start;
 397             }
 398             else
 399             {
 400                 yaz_mutex_leave(host->mutex);
 401                 connection_connect(con, iochan_man);
 402                 client_start_search(con->client);
 403                 goto start;
 404             }
 405         }
 406         else
 407         {
 408             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 409             con = con->next;
 410         }
 411     }
 412     yaz_mutex_leave(host->mutex);
 413 }
 414
 415 static struct host *connection_get_host(struct connection *con)
 416 {
 417     return con->host;
 418 }
 419
 420 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 421 {
 422     struct host *host = connection_get_host(con);
 423     ZOOM_options zoptions = ZOOM_options_create();
 424     const char *auth;
 425     const char *charset;
 426     const char *sru;
 427     const char *sru_version = 0;
 428
 429     struct session_database *sdb = client_get_database(con->client);
 430     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 431
 432     assert(con);
 433
 434     ZOOM_options_set(zoptions, "async", "1");
 435     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 436     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 437
 438     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 439         ZOOM_options_set(zoptions, "charset", charset);
 440
 441     assert(host->ipport);
 442     if (host->proxy)
 443     {
 444         yaz_log(YLOG_LOG, "proxy=%s", host->ipport);
 445         ZOOM_options_set(zoptions, "proxy", host->ipport);
 446     }
 447     else
 448     {
 449         assert(host->tproxy);
 450         yaz_log(YLOG_LOG, "tproxy=%s", host->ipport);
 451         ZOOM_options_set(zoptions, "tproxy", host->ipport);
 452     }
 453
 454     if (apdulog && *apdulog)
 455         ZOOM_options_set(zoptions, "apdulog", apdulog);
 456
 457     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 458         ZOOM_options_set(zoptions, "user", auth);
 459     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 460         ZOOM_options_set(zoptions, "sru", sru);
 461     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 462         && *sru_version)
 463         ZOOM_options_set(zoptions, "sru_version", sru_version);
 464     if (!(con->link = ZOOM_connection_create(zoptions)))
 465     {
 466         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 467         ZOOM_options_destroy(zoptions);
 468         return -1;
 469     }
 470
 471     if (sru && *sru)
 472     {
 473         char http_hostport[512];
 474         strcpy(http_hostport, "http://");
 475         strcat(http_hostport, host->url);
 476         yaz_log(YLOG_LOG, "SRU connect to : %s", http_hostport);
 477         ZOOM_connection_connect(con->link, http_hostport, 0);
 478     }
 479     else
 480     {
 481         ZOOM_connection_connect(con->link, host->url, 0);
 482     }
 483     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 484     con->state = Conn_Connecting;
 485     iochan_settimeout(con->iochan, con->operation_timeout);
 486     iochan_setdata(con->iochan, con);
 487     iochan_add(iochan_man, con->iochan);
 488
 489     client_set_state(con->client, Client_Connecting);
 490     ZOOM_options_destroy(zoptions);
 491     return 0;
 492 }
 493
 494 // Ensure that client has a connection associated
 495 int client_prep_connection(struct client *cl,
 496                            int operation_timeout, int session_timeout,
 497                            iochan_man_t iochan_man,
 498                            const struct timeval *abstime)
 499 {
 500     struct connection *co;
 501     struct session_database *sdb = client_get_database(cl);
 502     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 503     const char *url = session_setting_oneval(sdb, PZ_URL);
 504     const char *sru = session_setting_oneval(sdb, PZ_SRU);
 505     struct host *host = 0;
 506     int default_port = *sru ? 80 : 210;
 507
 508     if (zproxy && zproxy[0] == '\0')
 509         zproxy = 0;
 510
 511     if (!url || !*url)
 512         url = sdb->database->id;
 513
 514     host = find_host(client_get_session(cl)->service->server->database_hosts,
 515                      url, zproxy, default_port, iochan_man);
 516
 517     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
 518             client_get_id(cl), url);
 519     if (!host)
 520         return 0;
 521
 522     co = client_get_connection(cl);
 523
 524     if (co)
 525     {
 526         assert(co->host);
 527         if (co->host == host)
 528             ;  /* reusing connection. It's ours! */
 529         else
 530         {
 531             client_incref(cl);
 532             connection_release(co);
 533             co = 0;
 534         }
 535     }
 536     if (!co)
 537     {
 538         int max_connections = 0;
 539         int reuse_connections = 1;
 540         const char *v = session_setting_oneval(client_get_database(cl),
 541                                                PZ_MAX_CONNECTIONS);
 542         if (v && *v)
 543             max_connections = atoi(v);
 544
 545         v = session_setting_oneval(client_get_database(cl),
 546                 PZ_REUSE_CONNECTIONS);
 547         if (v && *v)
 548             reuse_connections = atoi(v);
 549
 550         // See if someone else has an idle connection
 551         // We should look at timestamps here to select the longest-idle connection
 552         yaz_mutex_enter(host->mutex);
 553         while (1)
 554         {
 555             int num_connections = 0;
 556             for (co = host->connections; co; co = co->next)
 557                 num_connections++;
 558             if (reuse_connections)
 559             {
 560                 for (co = host->connections; co; co = co->next)
 561                 {
 562                     if (connection_is_idle(co) &&
 563                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 564                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 565                                 session_setting_oneval(client_get_database(cl),
 566                                                        PZ_AUTHENTICATION)))
 567                     {
 568                         if (zproxy == 0 && co->zproxy == 0)
 569                             break;
 570                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 571                             break;
 572                     }
 573                 }
 574                 if (co)
 575                 {
 576                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 577                     break;
 578                 }
 579             }
 580             if (max_connections <= 0 || num_connections < max_connections)
 581             {
 582                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 583                         num_connections, max_connections);
 584                 break;
 585             }
 586             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 587                     num_connections, max_connections);
 588             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 589             {
 590                 yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
 591                 client_set_state(cl, Client_Error);
 592                 yaz_mutex_leave(host->mutex);
 593                 return 0;
 594             }
 595         }
 596         if (co)
 597         {
 598             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 599             connection_release(co);
 600             client_set_connection(cl, co);
 601             co->client = cl;
 602             /* ensure that connection is only assigned to this client
 603                by marking the client non Idle */
 604             client_set_state(cl, Client_Working);
 605             yaz_mutex_leave(host->mutex);
 606             co->operation_timeout = operation_timeout;
 607             co->session_timeout = session_timeout;
 608             /* tells ZOOM to reconnect if necessary. Disabled becuase
 609                the ZOOM_connection_connect flushes the task queue */
 610             ZOOM_connection_connect(co->link, 0, 0);
 611         }
 612         else
 613         {
 614             yaz_mutex_leave(host->mutex);
 615             co = connection_create(cl, host, operation_timeout, session_timeout,
 616                                    iochan_man);
 617         }
 618         assert(co->host);
 619     }
 620
 621     if (co && co->link)
 622         return 1;
 623     else
 624         return 0;
 625 }
 626
 627 /*
 628  * Local variables:
 629  * c-basic-offset: 4
 630  * c-file-style: "Stroustrup"
 631  * indent-tabs-mode: nil
 632  * End:
 633  * vim: shiftwidth=4 tabstop=8 expandtab
 634  */
 635