src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) 2006-2012 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->url);
 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     if (host->ipport)
 187         connection_connect(co, iochan_man);
 188
 189     yaz_mutex_enter(host->mutex);
 190     co->next = co->host->connections;
 191     co->host->connections = co;
 192     yaz_mutex_leave(host->mutex);
 193
 194     connection_use(1);
 195     return co;
 196 }
 197
 198 static void non_block_events(struct connection *co)
 199 {
 200     int got_records = 0;
 201     IOCHAN iochan = co->iochan;
 202     ZOOM_connection link = co->link;
 203     while (1)
 204     {
 205         struct client *cl = co->client;
 206         int ev;
 207         int r = ZOOM_event_nonblock(1, &link);
 208         if (!r)
 209             break;
 210         if (!cl)
 211             continue;
 212         ev = ZOOM_connection_last_event(link);
 213
 214 #if 1
 215         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 216 #endif
 217         switch (ev)
 218         {
 219         case ZOOM_EVENT_TIMEOUT:
 220             break;
 221         case ZOOM_EVENT_END:
 222             {
 223                 const char *error, *addinfo;
 224                 int err;
 225                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 226                 {
 227                     yaz_log(YLOG_LOG, "Error %s from %s",
 228                             error, client_get_id(cl));
 229                     client_set_diagnostic(cl, err, error, addinfo);
 230                     client_set_state(cl, Client_Error);
 231                 }
 232                 else
 233                 {
 234                     iochan_settimeout(iochan, co->session_timeout);
 235                     client_set_state(cl, Client_Idle);
 236                 }
 237                 yaz_cond_broadcast(co->host->cond_ready);
 238             }
 239             break;
 240         case ZOOM_EVENT_SEND_DATA:
 241             break;
 242         case ZOOM_EVENT_RECV_DATA:
 243             break;
 244         case ZOOM_EVENT_UNKNOWN:
 245             break;
 246         case ZOOM_EVENT_SEND_APDU:
 247             client_set_state(co->client, Client_Working);
 248             iochan_settimeout(iochan, co->operation_timeout);
 249             break;
 250         case ZOOM_EVENT_RECV_APDU:
 251             break;
 252         case ZOOM_EVENT_CONNECT:
 253             yaz_log(YLOG_LOG, "Connected to %s", client_get_id(cl));
 254             co->state = Conn_Open;
 255             break;
 256         case ZOOM_EVENT_RECV_SEARCH:
 257             client_search_response(cl);
 258             break;
 259         case ZOOM_EVENT_RECV_RECORD:
 260             client_record_response(cl);
 261             got_records = 1;
 262             break;
 263         default:
 264             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 265                     ev, client_get_id(cl));
 266             break;
 267         }
 268     }
 269     if (got_records)
 270     {
 271         struct client *cl = co->client;
 272         if (cl)
 273         {
 274             client_check_preferred_watch(cl);
 275             client_got_records(cl);
 276         }
 277     }
 278 }
 279
 280 void connection_continue(struct connection *co)
 281 {
 282     int r = ZOOM_connection_exec_task(co->link);
 283     if (!r)
 284     {
 285         const char *error, *addinfo;
 286         int err;
 287         if ((err = ZOOM_connection_error(co->link, &error, &addinfo)))
 288         {
 289             if (co->client)
 290             {
 291                 yaz_log(YLOG_LOG, "Error %s from %s",
 292                         error, client_get_id(co->client));
 293                 client_set_diagnostic(co->client, err, error, addinfo);
 294                 client_set_state_nb(co->client, Client_Error);
 295             }
 296         }
 297     }
 298     else
 299     {
 300         iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 301         iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 302     }
 303 }
 304
 305 static void connection_handler(IOCHAN iochan, int event)
 306 {
 307     struct connection *co = iochan_getdata(iochan);
 308     struct client *cl;
 309     struct host *host = co->host;
 310
 311     yaz_mutex_enter(host->mutex);
 312     cl = co->client;
 313     if (!cl)
 314     {
 315         /* no client associated with it.. We are probably getting
 316            a closed connection from the target.. Or, perhaps, an unexpected
 317            package.. We will just close the connection */
 318         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 319         remove_connection_from_host(co);
 320         yaz_mutex_leave(host->mutex);
 321         connection_destroy(co);
 322     }
 323     else if (event & EVENT_TIMEOUT)
 324     {
 325         ZOOM_connection_fire_event_timeout(co->link);
 326         client_lock(cl);
 327         non_block_events(co);
 328         client_unlock(cl);
 329
 330         remove_connection_from_host(co);
 331         yaz_mutex_leave(host->mutex);
 332         connection_destroy(co);
 333     }
 334     else
 335     {
 336         yaz_mutex_leave(host->mutex);
 337
 338         client_lock(cl);
 339         non_block_events(co);
 340
 341         ZOOM_connection_fire_event_socket(co->link, event);
 342
 343         non_block_events(co);
 344         client_unlock(cl);
 345
 346         if (co->link)
 347         {
 348             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 349             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 350         }
 351     }
 352 }
 353
 354
 355 // Disassociate connection from client
 356 static void connection_release(struct connection *co)
 357 {
 358     struct client *cl = co->client;
 359
 360     if (!cl)
 361         return;
 362     client_set_connection(cl, 0);
 363     co->client = 0;
 364 }
 365
 366 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 367 {
 368     struct connection *con;
 369
 370 start:
 371     yaz_mutex_enter(host->mutex);
 372     con = host->connections;
 373     while (con)
 374     {
 375         if (con->state == Conn_Closed)
 376         {
 377             if (!host->ipport) /* unresolved */
 378             {
 379                 remove_connection_from_host(con);
 380                 yaz_mutex_leave(host->mutex);
 381                 connection_destroy(con);
 382                 goto start;
 383                 /* start all over .. at some point it will be NULL */
 384             }
 385             else if (!con->client)
 386             {
 387                 remove_connection_from_host(con);
 388                 yaz_mutex_leave(host->mutex);
 389                 connection_destroy(con);
 390                 /* start all over .. at some point it will be NULL */
 391                 goto start;
 392             }
 393             else
 394             {
 395                 yaz_mutex_leave(host->mutex);
 396                 connection_connect(con, iochan_man);
 397                 client_start_search(con->client);
 398                 goto start;
 399             }
 400         }
 401         else
 402         {
 403             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 404             con = con->next;
 405         }
 406     }
 407     yaz_mutex_leave(host->mutex);
 408 }
 409
 410 static struct host *connection_get_host(struct connection *con)
 411 {
 412     return con->host;
 413 }
 414
 415 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 416 {
 417     struct host *host = connection_get_host(con);
 418     ZOOM_options zoptions = ZOOM_options_create();
 419     const char *auth;
 420     const char *charset;
 421     const char *sru;
 422     const char *sru_version = 0;
 423
 424     struct session_database *sdb = client_get_database(con->client);
 425     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 426
 427     assert(con);
 428
 429     ZOOM_options_set(zoptions, "async", "1");
 430     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 431     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 432
 433     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 434         ZOOM_options_set(zoptions, "charset", charset);
 435
 436     assert(host->ipport);
 437     if (host->proxy)
 438     {
 439         yaz_log(YLOG_LOG, "proxy=%s", host->ipport);
 440         ZOOM_options_set(zoptions, "proxy", host->ipport);
 441     }
 442     else
 443     {
 444         assert(host->tproxy);
 445         yaz_log(YLOG_LOG, "tproxy=%s", host->ipport);
 446         ZOOM_options_set(zoptions, "tproxy", host->ipport);
 447     }
 448
 449     if (apdulog && *apdulog)
 450         ZOOM_options_set(zoptions, "apdulog", apdulog);
 451
 452     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 453         ZOOM_options_set(zoptions, "user", auth);
 454     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 455         ZOOM_options_set(zoptions, "sru", sru);
 456     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 457         && *sru_version)
 458         ZOOM_options_set(zoptions, "sru_version", sru_version);
 459     if (!(con->link = ZOOM_connection_create(zoptions)))
 460     {
 461         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 462         ZOOM_options_destroy(zoptions);
 463         return -1;
 464     }
 465
 466     if (sru && *sru && !strstr(host->url, "://"))
 467     {
 468         char http_hostport[512];
 469         strcpy(http_hostport, "http://");
 470         strcat(http_hostport, host->url);
 471         ZOOM_connection_connect(con->link, http_hostport, 0);
 472     }
 473     else
 474     {
 475         ZOOM_connection_connect(con->link, host->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
 518     if (co)
 519     {
 520         assert(co->host);
 521         if (co->host == host && client_get_state(cl) == Client_Idle)
 522         {
 523             return 2;
 524         }
 525         client_incref(cl);
 526         connection_release(co);
 527         co = 0;
 528     }
 529     if (!co)
 530     {
 531         int max_connections = 0;
 532         int reuse_connections = 1;
 533         const char *v = session_setting_oneval(client_get_database(cl),
 534                                                PZ_MAX_CONNECTIONS);
 535         if (v && *v)
 536             max_connections = atoi(v);
 537
 538         v = session_setting_oneval(client_get_database(cl),
 539                 PZ_REUSE_CONNECTIONS);
 540         if (v && *v)
 541             reuse_connections = atoi(v);
 542
 543         // See if someone else has an idle connection
 544         // We should look at timestamps here to select the longest-idle connection
 545         yaz_mutex_enter(host->mutex);
 546         while (1)
 547         {
 548             int num_connections = 0;
 549             for (co = host->connections; co; co = co->next)
 550                 num_connections++;
 551             if (reuse_connections)
 552             {
 553                 for (co = host->connections; co; co = co->next)
 554                 {
 555                     if (connection_is_idle(co) &&
 556                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 557                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 558                                 session_setting_oneval(client_get_database(cl),
 559                                                        PZ_AUTHENTICATION)))
 560                     {
 561                         if (zproxy == 0 && co->zproxy == 0)
 562                             break;
 563                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 564                             break;
 565                     }
 566                 }
 567                 if (co)
 568                 {
 569                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 570                     break;
 571                 }
 572             }
 573             if (max_connections <= 0 || num_connections < max_connections)
 574             {
 575                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 576                         num_connections, max_connections);
 577                 break;
 578             }
 579             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 580                     num_connections, max_connections);
 581             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 582             {
 583                 yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
 584                 client_set_state(cl, Client_Error);
 585                 yaz_mutex_leave(host->mutex);
 586                 return 0;
 587             }
 588         }
 589         if (co)
 590         {
 591             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 592             connection_release(co);
 593             client_set_connection(cl, co);
 594             co->client = cl;
 595             /* ensure that connection is only assigned to this client
 596                by marking the client non Idle */
 597             client_set_state(cl, Client_Working);
 598             yaz_mutex_leave(host->mutex);
 599             co->operation_timeout = operation_timeout;
 600             co->session_timeout = session_timeout;
 601             /* tells ZOOM to reconnect if necessary. Disabled becuase
 602                the ZOOM_connection_connect flushes the task queue */
 603             ZOOM_connection_connect(co->link, 0, 0);
 604         }
 605         else
 606         {
 607             yaz_mutex_leave(host->mutex);
 608             co = connection_create(cl, host, 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