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() {
  75     return connection_use(0);
  76 }
  77
  78
  79 #else
  80 #define connection_use(x)
  81 #define connections_count(x) 0
  82 #define connections_count_total(x) 0
  83 #endif
  84
  85
  86 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  87  */
  88 struct connection {
  89     IOCHAN iochan;
  90     ZOOM_connection link;
  91     struct host *host;
  92     struct client *client;
  93     char *zproxy;
  94     enum {
  95         Conn_Resolving,
  96         Conn_Connecting,
  97         Conn_Open,
  98         Conn_Dead
  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->hostport);
 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                                             int operation_timeout,
 169                                             int session_timeout,
 170                                             iochan_man_t iochan_man)
 171 {
 172     struct connection *co;
 173     struct host *host = client_get_host(cl);
 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_Resolving;
 183     co->operation_timeout = operation_timeout;
 184     co->session_timeout = session_timeout;
 185     if (host->ipport)
 186         connection_connect(co, iochan_man);
 187
 188     yaz_mutex_enter(host->mutex);
 189     co->next = co->host->connections;
 190     co->host->connections = co;
 191     yaz_mutex_leave(host->mutex);
 192
 193     connection_use(1);
 194     return co;
 195 }
 196
 197 static void non_block_events(struct connection *co)
 198 {
 199     int got_records = 0;
 200     IOCHAN iochan = co->iochan;
 201     ZOOM_connection link = co->link;
 202     while (1)
 203     {
 204         struct client *cl = co->client;
 205         int ev;
 206         int r = ZOOM_event_nonblock(1, &link);
 207         if (!r)
 208             break;
 209         if (!cl)
 210             continue;
 211         ev = ZOOM_connection_last_event(link);
 212
 213 #if 1
 214         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 215 #endif
 216         switch (ev)
 217         {
 218         case ZOOM_EVENT_END:
 219             {
 220                 const char *error, *addinfo;
 221                 int err;
 222                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 223                 {
 224                     yaz_log(YLOG_LOG, "Error %s from %s",
 225                             error, client_get_url(cl));
 226                     client_set_diagnostic(cl, err);
 227                     client_set_state(cl, Client_Error);
 228                 }
 229                 else
 230                 {
 231                     iochan_settimeout(iochan, co->session_timeout);
 232                     client_set_state(cl, Client_Idle);
 233                 }
 234                 yaz_cond_broadcast(co->host->cond_ready);
 235             }
 236             break;
 237         case ZOOM_EVENT_SEND_DATA:
 238             break;
 239         case ZOOM_EVENT_RECV_DATA:
 240             break;
 241         case ZOOM_EVENT_UNKNOWN:
 242             break;
 243         case ZOOM_EVENT_SEND_APDU:
 244             client_set_state(co->client, Client_Working);
 245             iochan_settimeout(iochan, co->operation_timeout);
 246             break;
 247         case ZOOM_EVENT_RECV_APDU:
 248             break;
 249         case ZOOM_EVENT_CONNECT:
 250             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 251             co->state = Conn_Open;
 252             break;
 253         case ZOOM_EVENT_RECV_SEARCH:
 254             client_search_response(cl);
 255             break;
 256         case ZOOM_EVENT_RECV_RECORD:
 257             client_record_response(cl);
 258             got_records = 1;
 259             break;
 260         default:
 261             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 262                     ev, client_get_url(cl));
 263         }
 264     }
 265     if (got_records)
 266     {
 267         struct client *cl = co->client;
 268         if (cl)
 269         {
 270             client_check_preferred_watch(cl);
 271             client_got_records(cl);
 272         }
 273     }
 274 }
 275
 276 void connection_continue(struct connection *co)
 277 {
 278     int r = ZOOM_connection_exec_task(co->link);
 279     if (!r)
 280         yaz_log(YLOG_WARN, "No task was executed for connection");
 281     iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 282     iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 283 }
 284
 285 static void connection_handler(IOCHAN iochan, int event)
 286 {
 287     struct connection *co = iochan_getdata(iochan);
 288     struct client *cl;
 289     struct host *host = co->host;
 290
 291     yaz_mutex_enter(host->mutex);
 292     cl = co->client;
 293     if (!cl)
 294     {
 295         /* no client associated with it.. We are probably getting
 296            a closed connection from the target.. Or, perhaps, an unexpected
 297            package.. We will just close the connection */
 298         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 299         remove_connection_from_host(co);
 300         yaz_mutex_leave(host->mutex);
 301         connection_destroy(co);
 302     }
 303     else if (event & EVENT_TIMEOUT)
 304     {
 305         if (co->state == Conn_Connecting)
 306         {
 307             yaz_log(YLOG_WARN, "%p connect timeout %s", co, client_get_url(cl));
 308
 309             client_set_state(cl, Client_Error);
 310             remove_connection_from_host(co);
 311             yaz_mutex_leave(host->mutex);
 312             connection_destroy(co);
 313         }
 314         else
 315         {
 316             yaz_log(YLOG_LOG,  "%p Connection idle timeout %s", co, client_get_url(cl));
 317             remove_connection_from_host(co);
 318             yaz_mutex_leave(host->mutex);
 319             connection_destroy(co);
 320         }
 321     }
 322     else
 323     {
 324         yaz_mutex_leave(host->mutex);
 325
 326         client_lock(cl);
 327         non_block_events(co);
 328
 329         ZOOM_connection_fire_event_socket(co->link, event);
 330
 331         non_block_events(co);
 332         client_unlock(cl);
 333
 334         if (co->link)
 335         {
 336             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 337             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 338         }
 339     }
 340 }
 341
 342
 343 // Disassociate connection from client
 344 static void connection_release(struct connection *co)
 345 {
 346     struct client *cl = co->client;
 347
 348     if (!cl)
 349         return;
 350     client_set_connection(cl, 0);
 351     co->client = 0;
 352 }
 353
 354 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 355 {
 356     struct connection *con;
 357
 358 start:
 359     yaz_mutex_enter(host->mutex);
 360     con = host->connections;
 361     while (con)
 362     {
 363         if (con->state == Conn_Resolving)
 364         {
 365             if (!host->ipport) /* unresolved */
 366             {
 367                 remove_connection_from_host(con);
 368                 yaz_mutex_leave(host->mutex);
 369                 connection_destroy(con);
 370                 goto start;
 371                 /* start all over .. at some point it will be NULL */
 372             }
 373             else if (!con->client)
 374             {
 375                 remove_connection_from_host(con);
 376                 yaz_mutex_leave(host->mutex);
 377                 connection_destroy(con);
 378                 /* start all over .. at some point it will be NULL */
 379                 goto start;
 380             }
 381             else
 382             {
 383                 yaz_mutex_leave(host->mutex);
 384                 connection_connect(con, iochan_man);
 385                 client_start_search(con->client);
 386                 goto start;
 387             }
 388         }
 389         else
 390         {
 391             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 392             con = con->next;
 393         }
 394     }
 395     yaz_mutex_leave(host->mutex);
 396 }
 397
 398 static struct host *connection_get_host(struct connection *con)
 399 {
 400     return con->host;
 401 }
 402
 403 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 404 {
 405     ZOOM_connection link = 0;
 406     struct host *host = connection_get_host(con);
 407     ZOOM_options zoptions = ZOOM_options_create();
 408     const char *auth;
 409     const char *charset;
 410     const char *sru;
 411     const char *sru_version = 0;
 412
 413     struct session_database *sdb = client_get_database(con->client);
 414     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 415     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 416
 417     assert(host->ipport);
 418     assert(con);
 419
 420     ZOOM_options_set(zoptions, "async", "1");
 421     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 422     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 423
 424     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 425         ZOOM_options_set(zoptions, "charset", charset);
 426
 427     if (zproxy && *zproxy)
 428     {
 429         con->zproxy = xstrdup(zproxy);
 430         ZOOM_options_set(zoptions, "proxy", zproxy);
 431     }
 432     if (apdulog && *apdulog)
 433         ZOOM_options_set(zoptions, "apdulog", apdulog);
 434
 435     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 436         ZOOM_options_set(zoptions, "user", auth);
 437     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 438         ZOOM_options_set(zoptions, "sru", sru);
 439     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 440         && *sru_version)
 441         ZOOM_options_set(zoptions, "sru_version", sru_version);
 442     if (!(link = ZOOM_connection_create(zoptions)))
 443     {
 444         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 445         ZOOM_options_destroy(zoptions);
 446         return -1;
 447     }
 448
 449     if (sru && *sru)
 450     {
 451         char http_hostport[512];
 452         strcpy(http_hostport, "http://");
 453         strcat(http_hostport, host->hostport);
 454         ZOOM_connection_connect(link, http_hostport, 0);
 455     }
 456     else if (zproxy && *zproxy)
 457         ZOOM_connection_connect(link, host->hostport, 0);
 458     else
 459         ZOOM_connection_connect(link, host->ipport, 0);
 460
 461     con->link = link;
 462     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 463     con->state = Conn_Connecting;
 464     iochan_settimeout(con->iochan, con->operation_timeout);
 465     iochan_setdata(con->iochan, con);
 466     iochan_add(iochan_man, con->iochan);
 467
 468     /* this fragment is bad DRY: from client_prep_connection */
 469     client_set_state(con->client, Client_Connecting);
 470     ZOOM_options_destroy(zoptions);
 471     return 0;
 472 }
 473
 474 // Ensure that client has a connection associated
 475 int client_prep_connection(struct client *cl,
 476                            int operation_timeout, int session_timeout,
 477                            iochan_man_t iochan_man,
 478                            const struct timeval *abstime)
 479 {
 480     struct connection *co;
 481     struct host *host = client_get_host(cl);
 482     struct session_database *sdb = client_get_database(cl);
 483     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 484
 485     if (zproxy && zproxy[0] == '\0')
 486         zproxy = 0;
 487
 488     if (!host)
 489         return 0;
 490
 491     co = client_get_connection(cl);
 492
 493     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 494
 495     if (!co)
 496     {
 497         int max_connections = 0;
 498         int reuse_connections = 1;
 499         const char *v = session_setting_oneval(client_get_database(cl),
 500                                                PZ_MAX_CONNECTIONS);
 501         if (v && *v)
 502             max_connections = atoi(v);
 503
 504         v = session_setting_oneval(client_get_database(cl),
 505                 PZ_REUSE_CONNECTIONS);
 506         if (v && *v)
 507             reuse_connections = atoi(v);
 508
 509         // See if someone else has an idle connection
 510         // We should look at timestamps here to select the longest-idle connection
 511         yaz_mutex_enter(host->mutex);
 512         while (1)
 513         {
 514             int num_connections = 0;
 515             for (co = host->connections; co; co = co->next)
 516                 num_connections++;
 517             if (reuse_connections) {
 518                 for (co = host->connections; co; co = co->next)
 519                 {
 520                     if (connection_is_idle(co) &&
 521                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 522                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 523                                 session_setting_oneval(client_get_database(cl),
 524                                                        PZ_AUTHENTICATION)))
 525                     {
 526                         if (zproxy == 0 && co->zproxy == 0)
 527                             break;
 528                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 529                             break;
 530                     }
 531                 }
 532                 if (co)
 533                 {
 534                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 535                     break;
 536                 }
 537             }
 538             if (max_connections <= 0 || num_connections < max_connections)
 539             {
 540                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 541                         num_connections, max_connections);
 542                 break;
 543             }
 544             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 545                     num_connections, max_connections);
 546             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 547             {
 548                 yaz_log(YLOG_LOG, "out of connections %s", client_get_url(cl));
 549                 client_set_state(cl, Client_Error);
 550                 yaz_mutex_leave(host->mutex);
 551                 return 0;
 552             }
 553         }
 554         if (co)
 555         {
 556             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 557             connection_release(co);
 558             client_set_connection(cl, co);
 559             co->client = cl;
 560             /* ensure that connection is only assigned to this client
 561                by marking the client non Idle */
 562             client_set_state(cl, Client_Working);
 563             yaz_mutex_leave(host->mutex);
 564             co->operation_timeout = operation_timeout;
 565             co->session_timeout = session_timeout;
 566             /* tells ZOOM to reconnect if necessary. Disabled becuase
 567                the ZOOM_connection_connect flushes the task queue */
 568             ZOOM_connection_connect(co->link, 0, 0);
 569         }
 570         else
 571         {
 572             yaz_mutex_leave(host->mutex);
 573             co = connection_create(cl, operation_timeout, session_timeout,
 574                                    iochan_man);
 575         }
 576     }
 577
 578     if (co && co->link)
 579         return 1;
 580     else
 581         return 0;
 582 }
 583
 584 /*
 585  * Local variables:
 586  * c-basic-offset: 4
 587  * c-file-style: "Stroustrup"
 588  * indent-tabs-mode: nil
 589  * End:
 590  * vim: shiftwidth=4 tabstop=8 expandtab
 591  */
 592