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->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                                             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     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_id(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_id(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_id(cl));
 263             break;
 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 static struct host *connection_get_host(struct connection *con)
 372 {
 373     return con->host;
 374 }
 375
 376 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 377 {
 378     struct host *host = connection_get_host(con);
 379     ZOOM_options zoptions = ZOOM_options_create();
 380     const char *auth;
 381     const char *charset;
 382     const char *sru;
 383     const char *sru_version = 0;
 384
 385     struct session_database *sdb = client_get_database(con->client);
 386     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 387     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 388
 389     assert(con);
 390
 391     ZOOM_options_set(zoptions, "async", "1");
 392     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 393     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 394
 395     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 396         ZOOM_options_set(zoptions, "charset", charset);
 397
 398     if (zproxy && *zproxy)
 399     {
 400         con->zproxy = xstrdup(zproxy);
 401         ZOOM_options_set(zoptions, "proxy", zproxy);
 402     }
 403     if (apdulog && *apdulog)
 404         ZOOM_options_set(zoptions, "apdulog", apdulog);
 405
 406     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 407         ZOOM_options_set(zoptions, "user", auth);
 408     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 409         ZOOM_options_set(zoptions, "sru", sru);
 410     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 411         && *sru_version)
 412         ZOOM_options_set(zoptions, "sru_version", sru_version);
 413     if (!(con->link = ZOOM_connection_create(zoptions)))
 414     {
 415         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 416         ZOOM_options_destroy(zoptions);
 417         return -1;
 418     }
 419
 420     if (sru && *sru)
 421     {
 422         char http_hostport[512];
 423         strcpy(http_hostport, "http://");
 424         strcat(http_hostport, host->hostport);
 425         ZOOM_connection_connect(con->link, http_hostport, 0);
 426     }
 427     else
 428     {
 429         ZOOM_connection_connect(con->link, host->hostport, 0);
 430     }
 431
 432     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 433     con->state = Conn_Connecting;
 434     iochan_settimeout(con->iochan, con->operation_timeout);
 435     iochan_setdata(con->iochan, con);
 436     iochan_add(iochan_man, con->iochan);
 437
 438     client_set_state(con->client, Client_Connecting);
 439     ZOOM_options_destroy(zoptions);
 440     return 0;
 441 }
 442
 443 // Ensure that client has a connection associated
 444 int client_prep_connection(struct client *cl,
 445                            int operation_timeout, int session_timeout,
 446                            iochan_man_t iochan_man,
 447                            const struct timeval *abstime)
 448 {
 449     struct connection *co;
 450     struct session_database *sdb = client_get_database(cl);
 451     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 452     const char *url = session_setting_oneval(sdb, PZ_URL);
 453     struct host *host = 0;
 454
 455     if (zproxy && zproxy[0] == '\0')
 456         zproxy = 0;
 457
 458     if (!url || !*url)
 459         url = sdb->database->id;
 460
 461     host = find_host(client_get_session(cl)->service->server->database_hosts,
 462                      url);
 463
 464     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
 465             client_get_id(cl), url);
 466
 467     co = client_get_connection(cl);
 468
 469     if (co)
 470     {
 471         assert(co->host);
 472         if (co->host == host)
 473             ;  /* reusing connection. It's ours! */
 474         else
 475         {
 476             client_incref(cl);
 477             connection_release(co);
 478             co = 0;
 479         }
 480     }
 481     if (!co)
 482     {
 483         int max_connections = 0;
 484         int reuse_connections = 1;
 485         const char *v = session_setting_oneval(client_get_database(cl),
 486                                                PZ_MAX_CONNECTIONS);
 487         if (v && *v)
 488             max_connections = atoi(v);
 489
 490         v = session_setting_oneval(client_get_database(cl),
 491                 PZ_REUSE_CONNECTIONS);
 492         if (v && *v)
 493             reuse_connections = atoi(v);
 494
 495         // See if someone else has an idle connection
 496         // We should look at timestamps here to select the longest-idle connection
 497         yaz_mutex_enter(host->mutex);
 498         while (1)
 499         {
 500             int num_connections = 0;
 501             for (co = host->connections; co; co = co->next)
 502                 num_connections++;
 503             if (reuse_connections)
 504             {
 505                 for (co = host->connections; co; co = co->next)
 506                 {
 507                     if (connection_is_idle(co) &&
 508                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 509                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 510                                 session_setting_oneval(client_get_database(cl),
 511                                                        PZ_AUTHENTICATION)))
 512                     {
 513                         if (zproxy == 0 && co->zproxy == 0)
 514                             break;
 515                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 516                             break;
 517                     }
 518                 }
 519                 if (co)
 520                 {
 521                     yaz_log(YLOG_LOG, "Host %s: num_connections = %d (reusing)", host->hostport, num_connections);
 522                     break;
 523                 }
 524             }
 525             if (max_connections <= 0 || num_connections < max_connections)
 526             {
 527                 yaz_log(YLOG_LOG, "Host %s: num_connections = %d (new); max = %d",
 528                         host->hostport, num_connections, max_connections);
 529                 break;
 530             }
 531             yaz_log(YLOG_LOG, "Host %s: num_connections = %d (waiting) max = %d",
 532                     host->hostport, num_connections, max_connections);
 533             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 534             {
 535                 yaz_log(YLOG_LOG, "Host %s: out of connections %s", host->hostport, client_get_id(cl));
 536                 client_set_state(cl, Client_Error);
 537                 yaz_mutex_leave(host->mutex);
 538                 return 0;
 539             }
 540         }
 541         if (co)
 542         {
 543             yaz_log(YLOG_LOG,  "Host %s: %p Connection reuse. state: %d", host->hostport, co, co->state);
 544             connection_release(co);
 545             client_set_connection(cl, co);
 546             co->client = cl;
 547             /* ensure that connection is only assigned to this client
 548                by marking the client non Idle */
 549             client_set_state(cl, Client_Working);
 550             yaz_mutex_leave(host->mutex);
 551             co->operation_timeout = operation_timeout;
 552             co->session_timeout = session_timeout;
 553             /* tells ZOOM to reconnect if necessary. Disabled becuase
 554                the ZOOM_connection_connect flushes the task queue */
 555             ZOOM_connection_connect(co->link, 0, 0);
 556         }
 557         else
 558         {
 559             yaz_mutex_leave(host->mutex);
 560             co = connection_create(cl, host, operation_timeout, session_timeout, iochan_man);
 561             yaz_log(YLOG_LOG, "Host %s: %p Connection new", host->hostport, co);
 562
 563         }
 564         assert(co->host);
 565     }
 566
 567     if (co && co->link)
 568         return 1;
 569     else
 570         return 0;
 571 }
 572
 573 /*
 574  * Local variables:
 575  * c-basic-offset: 4
 576  * c-file-style: "Stroustrup"
 577  * indent-tabs-mode: nil
 578  * End:
 579  * vim: shiftwidth=4 tabstop=8 expandtab
 580  */
 581