src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) 2006-2013 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     char *url;
  96     enum {
  97         Conn_Closed,
  98         Conn_Connecting,
  99         Conn_Open
 100     } state;
 101     int operation_timeout;
 102     int session_timeout;
 103     struct connection *next; // next for same host or next in free list
 104 };
 105
 106 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
 107
 108 static int connection_is_idle(struct connection *co)
 109 {
 110     ZOOM_connection link = co->link;
 111     int event;
 112
 113     if (co->state != Conn_Open || !link)
 114         return 0;
 115
 116     if (!ZOOM_connection_is_idle(link))
 117         return 0;
 118     event = ZOOM_connection_peek_event(link);
 119     if (event == ZOOM_EVENT_NONE)
 120         return 1;
 121     else
 122         return 0;
 123 }
 124
 125 ZOOM_connection connection_get_link(struct connection *co)
 126 {
 127     return co->link;
 128 }
 129
 130 static void remove_connection_from_host(struct connection *con)
 131 {
 132     struct connection **conp = &con->host->connections;
 133     assert(con);
 134     while (*conp)
 135     {
 136         if (*conp == con)
 137         {
 138             *conp = (*conp)->next;
 139             break;
 140         }
 141         conp = &(*conp)->next;
 142     }
 143     yaz_cond_broadcast(con->host->cond_ready);
 144 }
 145
 146 // Close connection and recycle structure
 147 static void connection_destroy(struct connection *co)
 148 {
 149     if (co->link)
 150     {
 151         ZOOM_connection_destroy(co->link);
 152         iochan_destroy(co->iochan);
 153     }
 154     yaz_log(YLOG_DEBUG, "%p Connection destroy %s", co, co->url);
 155
 156     if (co->client)
 157     {
 158         client_disconnect(co->client);
 159     }
 160
 161     xfree(co->zproxy);
 162     xfree(co->url);
 163     xfree(co);
 164     connection_use(-1);
 165 }
 166
 167 // Creates a new connection for client, associated with the host of
 168 // client's database
 169 static struct connection *connection_create(struct client *cl,
 170                                             const char *url,
 171                                             struct host *host,
 172                                             int operation_timeout,
 173                                             int session_timeout,
 174                                             iochan_man_t iochan_man)
 175 {
 176     struct connection *co;
 177
 178     co = xmalloc(sizeof(*co));
 179     co->host = host;
 180
 181     co->client = cl;
 182     co->url = xstrdup(url);
 183     co->zproxy = 0;
 184     client_set_connection(cl, co);
 185     co->link = 0;
 186     co->state = Conn_Closed;
 187     co->operation_timeout = operation_timeout;
 188     co->session_timeout = session_timeout;
 189
 190     if (host->ipport)
 191         connection_connect(co, iochan_man);
 192
 193     yaz_mutex_enter(host->mutex);
 194     co->next = co->host->connections;
 195     co->host->connections = co;
 196     yaz_mutex_leave(host->mutex);
 197
 198     connection_use(1);
 199     return co;
 200 }
 201
 202 static void non_block_events(struct connection *co)
 203 {
 204     int got_records = 0;
 205     IOCHAN iochan = co->iochan;
 206     ZOOM_connection link = co->link;
 207     while (1)
 208     {
 209         struct client *cl = co->client;
 210         int ev;
 211         int r = ZOOM_event_nonblock(1, &link);
 212         if (!r)
 213             break;
 214         if (!cl)
 215             continue;
 216         ev = ZOOM_connection_last_event(link);
 217
 218 #if 1
 219         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 220 #endif
 221         switch (ev)
 222         {
 223         case ZOOM_EVENT_TIMEOUT:
 224             break;
 225         case ZOOM_EVENT_END:
 226             {
 227                 const char *error, *addinfo;
 228                 int err;
 229                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 230                 {
 231                     yaz_log(YLOG_LOG, "Error %s from %s",
 232                             error, client_get_id(cl));
 233                     client_set_diagnostic(cl, err, error, addinfo);
 234                     client_set_state(cl, Client_Error);
 235                 }
 236                 else
 237                 {
 238                     iochan_settimeout(iochan, co->session_timeout);
 239                     client_set_state(cl, Client_Idle);
 240                 }
 241                 yaz_cond_broadcast(co->host->cond_ready);
 242             }
 243             break;
 244         case ZOOM_EVENT_SEND_DATA:
 245             break;
 246         case ZOOM_EVENT_RECV_DATA:
 247             break;
 248         case ZOOM_EVENT_UNKNOWN:
 249             break;
 250         case ZOOM_EVENT_SEND_APDU:
 251             client_set_state(co->client, Client_Working);
 252             iochan_settimeout(iochan, co->operation_timeout);
 253             break;
 254         case ZOOM_EVENT_RECV_APDU:
 255             break;
 256         case ZOOM_EVENT_CONNECT:
 257             yaz_log(YLOG_LOG, "Connected to %s", client_get_id(cl));
 258             co->state = Conn_Open;
 259             break;
 260         case ZOOM_EVENT_RECV_SEARCH:
 261             client_search_response(cl);
 262             break;
 263         case ZOOM_EVENT_RECV_RECORD:
 264             client_record_response(cl, &got_records);
 265             break;
 266         default:
 267             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 268                     ev, client_get_id(cl));
 269             break;
 270         }
 271     }
 272     if (got_records)
 273     {
 274         struct client *cl = co->client;
 275         if (cl)
 276         {
 277             client_check_preferred_watch(cl);
 278             client_got_records(cl);
 279         }
 280     }
 281 }
 282
 283 void connection_continue(struct connection *co)
 284 {
 285     int r = ZOOM_connection_exec_task(co->link);
 286     if (!r)
 287         non_block_events(co);
 288     else
 289     {
 290         iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 291         iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 292     }
 293 }
 294
 295 static void connection_handler(IOCHAN iochan, int event)
 296 {
 297     struct connection *co = iochan_getdata(iochan);
 298     struct client *cl;
 299     struct host *host = co->host;
 300
 301     yaz_mutex_enter(host->mutex);
 302     cl = co->client;
 303     if (!cl)
 304     {
 305         /* no client associated with it.. We are probably getting
 306            a closed connection from the target.. Or, perhaps, an unexpected
 307            package.. We will just close the connection */
 308         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 309         remove_connection_from_host(co);
 310         yaz_mutex_leave(host->mutex);
 311         connection_destroy(co);
 312     }
 313     else if (event & EVENT_TIMEOUT)
 314     {
 315         ZOOM_connection_fire_event_timeout(co->link);
 316         client_lock(cl);
 317         non_block_events(co);
 318         client_unlock(cl);
 319
 320         remove_connection_from_host(co);
 321         yaz_mutex_leave(host->mutex);
 322         connection_destroy(co);
 323     }
 324     else
 325     {
 326         yaz_mutex_leave(host->mutex);
 327
 328         client_lock(cl);
 329         non_block_events(co);
 330
 331         ZOOM_connection_fire_event_socket(co->link, event);
 332
 333         non_block_events(co);
 334         client_unlock(cl);
 335
 336         if (co->link)
 337         {
 338             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 339             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 340         }
 341     }
 342 }
 343
 344
 345 // Disassociate connection from client
 346 static void connection_release(struct connection *co)
 347 {
 348     struct client *cl = co->client;
 349
 350     if (!cl)
 351         return;
 352     client_set_connection(cl, 0);
 353     co->client = 0;
 354 }
 355
 356 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 357 {
 358     struct connection *con;
 359
 360     yaz_mutex_enter(host->mutex);
 361     con = host->connections;
 362     while (con)
 363     {
 364         if (con->state == Conn_Closed)
 365         {
 366             if (!host->ipport || !con->client) /* unresolved or no client */
 367             {
 368                 remove_connection_from_host(con);
 369                 yaz_mutex_leave(host->mutex);
 370                 connection_destroy(con);
 371             }
 372             else
 373             {
 374                 struct session_database *sdb = client_get_database(con->client);
 375                 if (sdb)
 376                 {
 377                     yaz_mutex_leave(host->mutex);
 378                     connection_connect(con, iochan_man);
 379                     client_start_search(con->client);
 380                 }
 381                 else
 382                 {
 383                     remove_connection_from_host(con);
 384                     yaz_mutex_leave(host->mutex);
 385                     connection_destroy(con);
 386                 }
 387             }
 388             /* start all over .. at some point it will be NULL */
 389             yaz_mutex_enter(host->mutex);
 390             con = host->connections;
 391         }
 392         else
 393         {
 394             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 395             con = con->next;
 396         }
 397     }
 398     yaz_mutex_leave(host->mutex);
 399 }
 400
 401 static struct host *connection_get_host(struct connection *con)
 402 {
 403     return con->host;
 404 }
 405
 406 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 407 {
 408     struct host *host = connection_get_host(con);
 409     ZOOM_options zoptions = ZOOM_options_create();
 410     const char *auth;
 411     const char *charset;
 412     const char *sru;
 413     const char *sru_version = 0;
 414
 415     struct session_database *sdb = client_get_database(con->client);
 416     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 417
 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     assert(host->ipport);
 428     if (host->proxy)
 429     {
 430         yaz_log(YLOG_LOG, "proxy=%s", host->ipport);
 431         ZOOM_options_set(zoptions, "proxy", host->ipport);
 432     }
 433     else
 434     {
 435         assert(host->tproxy);
 436         yaz_log(YLOG_LOG, "tproxy=%s", host->ipport);
 437         ZOOM_options_set(zoptions, "tproxy", host->ipport);
 438     }
 439
 440     if (apdulog && *apdulog)
 441         ZOOM_options_set(zoptions, "apdulog", apdulog);
 442
 443     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 444         ZOOM_options_set(zoptions, "user", auth);
 445     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 446         ZOOM_options_set(zoptions, "sru", sru);
 447     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 448         && *sru_version)
 449         ZOOM_options_set(zoptions, "sru_version", sru_version);
 450     if (!(con->link = ZOOM_connection_create(zoptions)))
 451     {
 452         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 453         ZOOM_options_destroy(zoptions);
 454         return -1;
 455     }
 456
 457     if (sru && *sru && !strstr(con->url, "://"))
 458     {
 459         WRBUF w = wrbuf_alloc();
 460         wrbuf_puts(w, "http://");
 461         wrbuf_puts(w, con->url);
 462         ZOOM_connection_connect(con->link, wrbuf_cstr(w), 0);
 463         wrbuf_destroy(w);
 464     }
 465     else if (strchr(con->url, '#'))
 466     {
 467         const char *cp = strchr(con->url, '#');
 468         WRBUF w = wrbuf_alloc();
 469         wrbuf_write(w, con->url, cp - con->url);
 470         ZOOM_connection_connect(con->link, wrbuf_cstr(w), 0);
 471         wrbuf_destroy(w);
 472     }
 473     else
 474     {
 475         ZOOM_connection_connect(con->link, con->url, 0);
 476     }
 477     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 478     con->state = Conn_Connecting;
 479     iochan_settimeout(con->iochan, con->operation_timeout);
 480     iochan_setdata(con->iochan, con);
 481     iochan_add(iochan_man, con->iochan);
 482
 483     client_set_state(con->client, Client_Connecting);
 484     ZOOM_options_destroy(zoptions);
 485     return 0;
 486 }
 487
 488 // Ensure that client has a connection associated
 489 int client_prep_connection(struct client *cl,
 490                            int operation_timeout, int session_timeout,
 491                            iochan_man_t iochan_man,
 492                            const struct timeval *abstime)
 493 {
 494     struct connection *co;
 495     struct session_database *sdb = client_get_database(cl);
 496     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 497     const char *url = session_setting_oneval(sdb, PZ_URL);
 498     const char *sru = session_setting_oneval(sdb, PZ_SRU);
 499     struct host *host = 0;
 500     int default_port = *sru ? 80 : 210;
 501
 502     if (zproxy && zproxy[0] == '\0')
 503         zproxy = 0;
 504
 505     if (!url || !*url)
 506         url = sdb->database->id;
 507
 508     host = find_host(client_get_session(cl)->service->server->database_hosts,
 509                      url, zproxy, default_port, iochan_man);
 510
 511     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
 512             client_get_id(cl), url);
 513     if (!host)
 514         return 0;
 515
 516     co = client_get_connection(cl);
 517     if (co)
 518     {
 519         assert(co->host);
 520         if (co->host == host && client_get_state(cl) == Client_Idle)
 521         {
 522             return 2;
 523         }
 524         connection_release(co);
 525         co = 0;
 526     }
 527     if (!co)
 528     {
 529         int max_connections = 0;
 530         int reuse_connections = 1;
 531         const char *v = session_setting_oneval(client_get_database(cl),
 532                                                PZ_MAX_CONNECTIONS);
 533         if (v && *v)
 534             max_connections = atoi(v);
 535
 536         v = session_setting_oneval(client_get_database(cl),
 537                 PZ_REUSE_CONNECTIONS);
 538         if (v && *v)
 539             reuse_connections = atoi(v);
 540
 541         // See if someone else has an idle connection
 542         // We should look at timestamps here to select the longest-idle connection
 543         yaz_mutex_enter(host->mutex);
 544         while (1)
 545         {
 546             int num_connections = 0;
 547             for (co = host->connections; co; co = co->next)
 548                 num_connections++;
 549             if (reuse_connections)
 550             {
 551                 for (co = host->connections; co; co = co->next)
 552                 {
 553                     if (connection_is_idle(co) &&
 554                         !strcmp(url, co->url) &&
 555                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 556                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 557                                 session_setting_oneval(client_get_database(cl),
 558                                                        PZ_AUTHENTICATION)))
 559                     {
 560                         if (zproxy == 0 && co->zproxy == 0)
 561                             break;
 562                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 563                             break;
 564                     }
 565                 }
 566                 if (co)
 567                 {
 568                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 569                     break;
 570                 }
 571             }
 572             if (max_connections <= 0 || num_connections < max_connections)
 573             {
 574                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 575                         num_connections, max_connections);
 576                 break;
 577             }
 578             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 579                     num_connections, max_connections);
 580             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 581             {
 582                 yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
 583                 client_set_state(cl, Client_Error);
 584                 yaz_mutex_leave(host->mutex);
 585                 return 0;
 586             }
 587         }
 588         if (co)
 589         {
 590             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 591             connection_release(co);
 592             client_set_connection(cl, co);
 593             co->client = cl;
 594             /* ensure that connection is only assigned to this client
 595                by marking the client non Idle */
 596             client_set_state(cl, Client_Working);
 597             yaz_mutex_leave(host->mutex);
 598             co->operation_timeout = operation_timeout;
 599             co->session_timeout = session_timeout;
 600             /* tells ZOOM to reconnect if necessary. Disabled becuase
 601                the ZOOM_connection_connect flushes the task queue */
 602             ZOOM_connection_connect(co->link, 0, 0);
 603         }
 604         else
 605         {
 606             yaz_mutex_leave(host->mutex);
 607             co = connection_create(cl, url, host,
 608                                    operation_timeout, session_timeout,
 609                                    iochan_man);
 610         }
 611         assert(co->host);
 612     }
 613
 614     if (co && co->link)
 615         return 1;
 616     else
 617         return 0;
 618 }
 619
 620 /*
 621  * Local variables:
 622  * c-basic-offset: 4
 623  * c-file-style: "Stroustrup"
 624  * indent-tabs-mode: nil
 625  * End:
 626  * vim: shiftwidth=4 tabstop=8 expandtab
 627  */
 628