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         }
 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     {
 281         const char *error, *addinfo;
 282         int err;
 283         if ((err = ZOOM_connection_error(co->link, &error, &addinfo)))
 284         {
 285             if (co->client)
 286             {
 287                 yaz_log(YLOG_LOG, "Error %s from %s",
 288                         error, client_get_id(co->client));
 289                 client_set_diagnostic(co->client, err);
 290                 client_set_state_nb(co->client, Client_Error);
 291             }
 292         }
 293     }
 294     else
 295     {
 296         iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 297         iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 298     }
 299 }
 300
 301 static void connection_handler(IOCHAN iochan, int event)
 302 {
 303     struct connection *co = iochan_getdata(iochan);
 304     struct client *cl;
 305     struct host *host = co->host;
 306
 307     yaz_mutex_enter(host->mutex);
 308     cl = co->client;
 309     if (!cl)
 310     {
 311         /* no client associated with it.. We are probably getting
 312            a closed connection from the target.. Or, perhaps, an unexpected
 313            package.. We will just close the connection */
 314         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 315         remove_connection_from_host(co);
 316         yaz_mutex_leave(host->mutex);
 317         connection_destroy(co);
 318     }
 319     else if (event & EVENT_TIMEOUT)
 320     {
 321         if (co->state == Conn_Connecting)
 322         {
 323             yaz_log(YLOG_WARN, "%p connect timeout %s", co, client_get_id(cl));
 324
 325             client_set_state(cl, Client_Error);
 326             remove_connection_from_host(co);
 327             yaz_mutex_leave(host->mutex);
 328             connection_destroy(co);
 329         }
 330         else
 331         {
 332             yaz_log(YLOG_LOG,  "%p Connection idle timeout %s", co, client_get_id(cl));
 333             remove_connection_from_host(co);
 334             yaz_mutex_leave(host->mutex);
 335             connection_destroy(co);
 336         }
 337     }
 338     else
 339     {
 340         yaz_mutex_leave(host->mutex);
 341
 342         client_lock(cl);
 343         non_block_events(co);
 344
 345         ZOOM_connection_fire_event_socket(co->link, event);
 346
 347         non_block_events(co);
 348         client_unlock(cl);
 349
 350         if (co->link)
 351         {
 352             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 353             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 354         }
 355     }
 356 }
 357
 358
 359 // Disassociate connection from client
 360 static void connection_release(struct connection *co)
 361 {
 362     struct client *cl = co->client;
 363
 364     if (!cl)
 365         return;
 366     client_set_connection(cl, 0);
 367     co->client = 0;
 368 }
 369
 370 static struct host *connection_get_host(struct connection *con)
 371 {
 372     return con->host;
 373 }
 374
 375 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 376 {
 377     struct host *host = connection_get_host(con);
 378     ZOOM_options zoptions = ZOOM_options_create();
 379     const char *auth;
 380     const char *charset;
 381     const char *sru;
 382     const char *sru_version = 0;
 383
 384     struct session_database *sdb = client_get_database(con->client);
 385     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 386     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 387
 388     assert(con);
 389
 390     ZOOM_options_set(zoptions, "async", "1");
 391     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 392     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 393
 394     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 395         ZOOM_options_set(zoptions, "charset", charset);
 396
 397     if (zproxy && *zproxy)
 398     {
 399         con->zproxy = xstrdup(zproxy);
 400         ZOOM_options_set(zoptions, "proxy", zproxy);
 401     }
 402     if (apdulog && *apdulog)
 403         ZOOM_options_set(zoptions, "apdulog", apdulog);
 404
 405     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 406         ZOOM_options_set(zoptions, "user", auth);
 407     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 408         ZOOM_options_set(zoptions, "sru", sru);
 409     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 410         && *sru_version)
 411         ZOOM_options_set(zoptions, "sru_version", sru_version);
 412     if (!(con->link = ZOOM_connection_create(zoptions)))
 413     {
 414         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 415         ZOOM_options_destroy(zoptions);
 416         return -1;
 417     }
 418
 419     if (sru && *sru)
 420     {
 421         char http_hostport[512];
 422         strcpy(http_hostport, "http://");
 423         strcat(http_hostport, host->hostport);
 424         ZOOM_connection_connect(con->link, http_hostport, 0);
 425     }
 426     else
 427     {
 428         ZOOM_connection_connect(con->link, host->hostport, 0);
 429     }
 430
 431     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 432     con->state = Conn_Connecting;
 433     iochan_settimeout(con->iochan, con->operation_timeout);
 434     iochan_setdata(con->iochan, con);
 435     iochan_add(iochan_man, con->iochan);
 436
 437     client_set_state(con->client, Client_Connecting);
 438     ZOOM_options_destroy(zoptions);
 439     return 0;
 440 }
 441
 442 // Ensure that client has a connection associated
 443 int client_prep_connection(struct client *cl,
 444                            int operation_timeout, int session_timeout,
 445                            iochan_man_t iochan_man,
 446                            const struct timeval *abstime)
 447 {
 448     struct connection *co;
 449     struct session_database *sdb = client_get_database(cl);
 450     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 451     const char *url = session_setting_oneval(sdb, PZ_URL);
 452     struct host *host = 0;
 453
 454     if (zproxy && zproxy[0] == '\0')
 455         zproxy = 0;
 456
 457     if (!url || !*url)
 458         url = sdb->database->id;
 459
 460     host = find_host(client_get_session(cl)->service->server->database_hosts,
 461                      url);
 462
 463     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
 464             client_get_id(cl), url);
 465
 466     co = client_get_connection(cl);
 467
 468     if (co)
 469     {
 470         assert(co->host);
 471         if (co->host == host)
 472             ;  /* reusing connection. It's ours! */
 473         else
 474         {
 475             client_incref(cl);
 476             connection_release(co);
 477             co = 0;
 478         }
 479     }
 480     if (!co)
 481     {
 482         int max_connections = 0;
 483         int reuse_connections = 1;
 484         const char *v = session_setting_oneval(client_get_database(cl),
 485                                                PZ_MAX_CONNECTIONS);
 486         if (v && *v)
 487             max_connections = atoi(v);
 488
 489         v = session_setting_oneval(client_get_database(cl),
 490                 PZ_REUSE_CONNECTIONS);
 491         if (v && *v)
 492             reuse_connections = atoi(v);
 493
 494         // See if someone else has an idle connection
 495         // We should look at timestamps here to select the longest-idle connection
 496         yaz_mutex_enter(host->mutex);
 497         while (1)
 498         {
 499             int num_connections = 0;
 500             for (co = host->connections; co; co = co->next)
 501                 num_connections++;
 502             if (reuse_connections)
 503             {
 504                 for (co = host->connections; co; co = co->next)
 505                 {
 506                     if (connection_is_idle(co) &&
 507                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 508                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 509                                 session_setting_oneval(client_get_database(cl),
 510                                                        PZ_AUTHENTICATION)))
 511                     {
 512                         if (zproxy == 0 && co->zproxy == 0)
 513                             break;
 514                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 515                             break;
 516                     }
 517                 }
 518                 if (co)
 519                 {
 520                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 521                     break;
 522                 }
 523             }
 524             if (max_connections <= 0 || num_connections < max_connections)
 525             {
 526                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 527                         num_connections, max_connections);
 528                 break;
 529             }
 530             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 531                     num_connections, max_connections);
 532             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 533             {
 534                 yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
 535                 client_set_state(cl, Client_Error);
 536                 yaz_mutex_leave(host->mutex);
 537                 return 0;
 538             }
 539         }
 540         if (co)
 541         {
 542             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 543             connection_release(co);
 544             client_set_connection(cl, co);
 545             co->client = cl;
 546             /* ensure that connection is only assigned to this client
 547                by marking the client non Idle */
 548             client_set_state(cl, Client_Working);
 549             yaz_mutex_leave(host->mutex);
 550             co->operation_timeout = operation_timeout;
 551             co->session_timeout = session_timeout;
 552             /* tells ZOOM to reconnect if necessary. Disabled becuase
 553                the ZOOM_connection_connect flushes the task queue */
 554             ZOOM_connection_connect(co->link, 0, 0);
 555         }
 556         else
 557         {
 558             yaz_mutex_leave(host->mutex);
 559             co = connection_create(cl, host, operation_timeout, session_timeout,
 560                                    iochan_man);
 561         }
 562         assert(co->host);
 563     }
 564
 565     if (co && co->link)
 566         return 1;
 567     else
 568         return 0;
 569 }
 570
 571 /*
 572  * Local variables:
 573  * c-basic-offset: 4
 574  * c-file-style: "Stroustrup"
 575  * indent-tabs-mode: nil
 576  * End:
 577  * vim: shiftwidth=4 tabstop=8 expandtab
 578  */
 579