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 static void connection_use(int delta)
  56 {
  57     int result;
  58     if (!g_mutex)
  59         yaz_mutex_create(&g_mutex);
  60     yaz_mutex_enter(g_mutex);
  61     no_connections += delta;
  62     result = no_connection;
  63     if (delta > 0)
  64         total_no_connections += delta;
  65     yaz_mutex_leave(g_mutex);
  66     if (delta == 0)
  67             return result;
  68     yaz_log(YLOG_LOG, "%s connections=%d", delta > 0 ? "INC" : "DEC",
  69             no_connections);
  70     return result;
  71 }
  72
  73 int connections_count() {
  74     return connection_use(0);
  75 }
  76
  77
  78 #else
  79 #define connection_use(x)
  80 #define connections_count(x) 0
  81 #define connections_count_total(x) 0
  82 #endif
  83
  84
  85 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  86  */
  87 struct connection {
  88     IOCHAN iochan;
  89     ZOOM_connection link;
  90     struct host *host;
  91     struct client *client;
  92     char *zproxy;
  93     enum {
  94         Conn_Resolving,
  95         Conn_Connecting,
  96         Conn_Open,
  97         Conn_Dead
  98     } state;
  99     int operation_timeout;
 100     int session_timeout;
 101     struct connection *next; // next for same host or next in free list
 102 };
 103
 104 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
 105
 106 static int connection_is_idle(struct connection *co)
 107 {
 108     ZOOM_connection link = co->link;
 109     int event;
 110
 111     if (co->state != Conn_Open || !link)
 112         return 0;
 113
 114     if (!ZOOM_connection_is_idle(link))
 115         return 0;
 116     event = ZOOM_connection_peek_event(link);
 117     if (event == ZOOM_EVENT_NONE)
 118         return 1;
 119     else
 120         return 0;
 121 }
 122
 123 ZOOM_connection connection_get_link(struct connection *co)
 124 {
 125     return co->link;
 126 }
 127
 128 static void remove_connection_from_host(struct connection *con)
 129 {
 130     struct connection **conp = &con->host->connections;
 131     assert(con);
 132     while (*conp)
 133     {
 134         if (*conp == con)
 135         {
 136             *conp = (*conp)->next;
 137             break;
 138         }
 139         conp = &(*conp)->next;
 140     }
 141     yaz_cond_broadcast(con->host->cond_ready);
 142 }
 143
 144 // Close connection and recycle structure
 145 static void connection_destroy(struct connection *co)
 146 {
 147     if (co->link)
 148     {
 149         ZOOM_connection_destroy(co->link);
 150         iochan_destroy(co->iochan);
 151     }
 152     yaz_log(YLOG_DEBUG, "%p Connection destroy %s", co, co->host->hostport);
 153
 154     if (co->client)
 155     {
 156         client_disconnect(co->client);
 157     }
 158
 159     xfree(co->zproxy);
 160     xfree(co);
 161     connection_use(-1);
 162 }
 163
 164 // Creates a new connection for client, associated with the host of
 165 // client's database
 166 static struct connection *connection_create(struct client *cl,
 167                                             int operation_timeout,
 168                                             int session_timeout,
 169                                             iochan_man_t iochan_man)
 170 {
 171     struct connection *co;
 172     struct host *host = client_get_host(cl);
 173
 174     co = xmalloc(sizeof(*co));
 175     co->host = host;
 176
 177     co->client = cl;
 178     co->zproxy = 0;
 179     client_set_connection(cl, co);
 180     co->link = 0;
 181     co->state = Conn_Resolving;
 182     co->operation_timeout = operation_timeout;
 183     co->session_timeout = session_timeout;
 184     if (host->ipport)
 185         connection_connect(co, iochan_man);
 186
 187     yaz_mutex_enter(host->mutex);
 188     co->next = co->host->connections;
 189     co->host->connections = co;
 190     yaz_mutex_leave(host->mutex);
 191
 192     connection_use(1);
 193     return co;
 194 }
 195
 196 static void non_block_events(struct connection *co)
 197 {
 198     int got_records = 0;
 199     IOCHAN iochan = co->iochan;
 200     ZOOM_connection link = co->link;
 201     while (1)
 202     {
 203         struct client *cl = co->client;
 204         int ev;
 205         int r = ZOOM_event_nonblock(1, &link);
 206         if (!r)
 207             break;
 208         if (!cl)
 209             continue;
 210         ev = ZOOM_connection_last_event(link);
 211
 212 #if 1
 213         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 214 #endif
 215         switch (ev)
 216         {
 217         case ZOOM_EVENT_END:
 218             {
 219                 const char *error, *addinfo;
 220                 int err;
 221                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 222                 {
 223                     yaz_log(YLOG_LOG, "Error %s from %s",
 224                             error, client_get_url(cl));
 225                     client_set_diagnostic(cl, err);
 226                     client_set_state(cl, Client_Error);
 227                 }
 228                 else
 229                 {
 230                     iochan_settimeout(iochan, co->session_timeout);
 231                     client_set_state(cl, Client_Idle);
 232                 }
 233                 yaz_cond_broadcast(co->host->cond_ready);
 234             }
 235             break;
 236         case ZOOM_EVENT_SEND_DATA:
 237             break;
 238         case ZOOM_EVENT_RECV_DATA:
 239             break;
 240         case ZOOM_EVENT_UNKNOWN:
 241             break;
 242         case ZOOM_EVENT_SEND_APDU:
 243             client_set_state(co->client, Client_Working);
 244             iochan_settimeout(iochan, co->operation_timeout);
 245             break;
 246         case ZOOM_EVENT_RECV_APDU:
 247             break;
 248         case ZOOM_EVENT_CONNECT:
 249             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 250             co->state = Conn_Open;
 251             break;
 252         case ZOOM_EVENT_RECV_SEARCH:
 253             client_search_response(cl);
 254             break;
 255         case ZOOM_EVENT_RECV_RECORD:
 256             client_record_response(cl);
 257             got_records = 1;
 258             break;
 259         default:
 260             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 261                     ev, client_get_url(cl));
 262         }
 263     }
 264     if (got_records)
 265     {
 266         struct client *cl = co->client;
 267         if (cl)
 268         {
 269             client_check_preferred_watch(cl);
 270             client_got_records(cl);
 271         }
 272     }
 273 }
 274
 275 void connection_continue(struct connection *co)
 276 {
 277     int r = ZOOM_connection_exec_task(co->link);
 278     if (!r)
 279         yaz_log(YLOG_WARN, "No task was executed for connection");
 280     iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 281     iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 282 }
 283
 284 static void connection_handler(IOCHAN iochan, int event)
 285 {
 286     struct connection *co = iochan_getdata(iochan);
 287     struct client *cl;
 288     struct host *host = co->host;
 289
 290     yaz_mutex_enter(host->mutex);
 291     cl = co->client;
 292     if (!cl)
 293     {
 294         /* no client associated with it.. We are probably getting
 295            a closed connection from the target.. Or, perhaps, an unexpected
 296            package.. We will just close the connection */
 297         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 298         remove_connection_from_host(co);
 299         yaz_mutex_leave(host->mutex);
 300         connection_destroy(co);
 301     }
 302     else if (event & EVENT_TIMEOUT)
 303     {
 304         if (co->state == Conn_Connecting)
 305         {
 306             yaz_log(YLOG_WARN, "%p connect timeout %s", co, client_get_url(cl));
 307
 308             client_set_state(cl, Client_Error);
 309             remove_connection_from_host(co);
 310             yaz_mutex_leave(host->mutex);
 311             connection_destroy(co);
 312         }
 313         else
 314         {
 315             yaz_log(YLOG_LOG,  "%p Connection idle timeout %s", co, client_get_url(cl));
 316             remove_connection_from_host(co);
 317             yaz_mutex_leave(host->mutex);
 318             connection_destroy(co);
 319         }
 320     }
 321     else
 322     {
 323         yaz_mutex_leave(host->mutex);
 324
 325         client_lock(cl);
 326         non_block_events(co);
 327
 328         ZOOM_connection_fire_event_socket(co->link, event);
 329
 330         non_block_events(co);
 331         client_unlock(cl);
 332
 333         if (co->link)
 334         {
 335             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 336             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 337         }
 338     }
 339 }
 340
 341
 342 // Disassociate connection from client
 343 static void connection_release(struct connection *co)
 344 {
 345     struct client *cl = co->client;
 346
 347     if (!cl)
 348         return;
 349     client_set_connection(cl, 0);
 350     co->client = 0;
 351 }
 352
 353 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 354 {
 355     struct connection *con;
 356
 357 start:
 358     yaz_mutex_enter(host->mutex);
 359     con = host->connections;
 360     while (con)
 361     {
 362         if (con->state == Conn_Resolving)
 363         {
 364             if (!host->ipport) /* unresolved */
 365             {
 366                 remove_connection_from_host(con);
 367                 yaz_mutex_leave(host->mutex);
 368                 connection_destroy(con);
 369                 goto start;
 370                 /* start all over .. at some point it will be NULL */
 371             }
 372             else if (!con->client)
 373             {
 374                 remove_connection_from_host(con);
 375                 yaz_mutex_leave(host->mutex);
 376                 connection_destroy(con);
 377                 /* start all over .. at some point it will be NULL */
 378                 goto start;
 379             }
 380             else
 381             {
 382                 yaz_mutex_leave(host->mutex);
 383                 connection_connect(con, iochan_man);
 384                 client_start_search(con->client);
 385                 goto start;
 386             }
 387         }
 388         else
 389         {
 390             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 391             con = con->next;
 392         }
 393     }
 394     yaz_mutex_leave(host->mutex);
 395 }
 396
 397 static struct host *connection_get_host(struct connection *con)
 398 {
 399     return con->host;
 400 }
 401
 402 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 403 {
 404     ZOOM_connection link = 0;
 405     struct host *host = connection_get_host(con);
 406     ZOOM_options zoptions = ZOOM_options_create();
 407     const char *auth;
 408     const char *charset;
 409     const char *sru;
 410     const char *sru_version = 0;
 411
 412     struct session_database *sdb = client_get_database(con->client);
 413     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 414     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 415
 416     assert(host->ipport);
 417     assert(con);
 418
 419     ZOOM_options_set(zoptions, "async", "1");
 420     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 421     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 422
 423     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 424         ZOOM_options_set(zoptions, "charset", charset);
 425
 426     if (zproxy && *zproxy)
 427     {
 428         con->zproxy = xstrdup(zproxy);
 429         ZOOM_options_set(zoptions, "proxy", zproxy);
 430     }
 431     if (apdulog && *apdulog)
 432         ZOOM_options_set(zoptions, "apdulog", apdulog);
 433
 434     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 435         ZOOM_options_set(zoptions, "user", auth);
 436     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 437         ZOOM_options_set(zoptions, "sru", sru);
 438     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 439         && *sru_version)
 440         ZOOM_options_set(zoptions, "sru_version", sru_version);
 441     if (!(link = ZOOM_connection_create(zoptions)))
 442     {
 443         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 444         ZOOM_options_destroy(zoptions);
 445         return -1;
 446     }
 447
 448     if (sru && *sru)
 449     {
 450         char http_hostport[512];
 451         strcpy(http_hostport, "http://");
 452         strcat(http_hostport, host->hostport);
 453         ZOOM_connection_connect(link, http_hostport, 0);
 454     }
 455     else if (zproxy && *zproxy)
 456         ZOOM_connection_connect(link, host->hostport, 0);
 457     else
 458         ZOOM_connection_connect(link, host->ipport, 0);
 459
 460     con->link = link;
 461     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 462     con->state = Conn_Connecting;
 463     iochan_settimeout(con->iochan, con->operation_timeout);
 464     iochan_setdata(con->iochan, con);
 465     iochan_add(iochan_man, con->iochan);
 466
 467     /* this fragment is bad DRY: from client_prep_connection */
 468     client_set_state(con->client, Client_Connecting);
 469     ZOOM_options_destroy(zoptions);
 470     return 0;
 471 }
 472
 473 // Ensure that client has a connection associated
 474 int client_prep_connection(struct client *cl,
 475                            int operation_timeout, int session_timeout,
 476                            iochan_man_t iochan_man,
 477                            const struct timeval *abstime)
 478 {
 479     struct connection *co;
 480     struct host *host = client_get_host(cl);
 481     struct session_database *sdb = client_get_database(cl);
 482     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 483
 484     if (zproxy && zproxy[0] == '\0')
 485         zproxy = 0;
 486
 487     if (!host)
 488         return 0;
 489
 490     co = client_get_connection(cl);
 491
 492     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 493
 494     if (!co)
 495     {
 496         int max_connections = 0;
 497         int reuse_connections = 1;
 498         const char *v = session_setting_oneval(client_get_database(cl),
 499                                                PZ_MAX_CONNECTIONS);
 500         if (v && *v)
 501             max_connections = atoi(v);
 502
 503         v = session_setting_oneval(client_get_database(cl),
 504                 PZ_REUSE_CONNECTIONS);
 505         if (v && *v)
 506             reuse_connections = atoi(v);
 507
 508         // See if someone else has an idle connection
 509         // We should look at timestamps here to select the longest-idle connection
 510         yaz_mutex_enter(host->mutex);
 511         while (1)
 512         {
 513             int num_connections = 0;
 514             for (co = host->connections; co; co = co->next)
 515                 num_connections++;
 516             if (reuse_connections) {
 517                 for (co = host->connections; co; co = co->next)
 518                 {
 519                     if (connection_is_idle(co) &&
 520                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 521                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 522                                 session_setting_oneval(client_get_database(cl),
 523                                                        PZ_AUTHENTICATION)))
 524                     {
 525                         if (zproxy == 0 && co->zproxy == 0)
 526                             break;
 527                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 528                             break;
 529                     }
 530                 }
 531                 if (co)
 532                 {
 533                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 534                     break;
 535                 }
 536             }
 537             if (max_connections <= 0 || num_connections < max_connections)
 538             {
 539                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 540                         num_connections, max_connections);
 541                 break;
 542             }
 543             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 544                     num_connections, max_connections);
 545             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 546             {
 547                 yaz_log(YLOG_LOG, "out of connections %s", client_get_url(cl));
 548                 client_set_state(cl, Client_Error);
 549                 yaz_mutex_leave(host->mutex);
 550                 return 0;
 551             }
 552         }
 553         if (co)
 554         {
 555             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 556             connection_release(co);
 557             client_set_connection(cl, co);
 558             co->client = cl;
 559             /* ensure that connection is only assigned to this client
 560                by marking the client non Idle */
 561             client_set_state(cl, Client_Working);
 562             yaz_mutex_leave(host->mutex);
 563             co->operation_timeout = operation_timeout;
 564             co->session_timeout = session_timeout;
 565             /* tells ZOOM to reconnect if necessary. Disabled becuase
 566                the ZOOM_connection_connect flushes the task queue */
 567             ZOOM_connection_connect(co->link, 0, 0);
 568         }
 569         else
 570         {
 571             yaz_mutex_leave(host->mutex);
 572             co = connection_create(cl, operation_timeout, session_timeout,
 573                                    iochan_man);
 574         }
 575     }
 576
 577     if (co && co->link)
 578         return 1;
 579     else
 580         return 0;
 581 }
 582
 583 /*
 584  * Local variables:
 585  * c-basic-offset: 4
 586  * c-file-style: "Stroustrup"
 587  * indent-tabs-mode: nil
 588  * End:
 589  * vim: shiftwidth=4 tabstop=8 expandtab
 590  */
 591