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_Resolving,
  97         Conn_Connecting,
  98         Conn_Open,
  99         Conn_Dead
 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->host->hostport);
 155
 156     if (co->client)
 157     {
 158         client_disconnect(co->client);
 159     }
 160
 161     xfree(co->zproxy);
 162     xfree(co);
 163     connection_use(-1);
 164 }
 165
 166 // Creates a new connection for client, associated with the host of
 167 // client's database
 168 static struct connection *connection_create(struct client *cl,
 169                                             struct host *host,
 170                                             int operation_timeout,
 171                                             int session_timeout,
 172                                             iochan_man_t iochan_man)
 173 {
 174     struct connection *co;
 175
 176     co = xmalloc(sizeof(*co));
 177     co->host = host;
 178
 179     co->client = cl;
 180     co->zproxy = 0;
 181     client_set_connection(cl, co);
 182     co->link = 0;
 183     co->state = Conn_Resolving;
 184     co->operation_timeout = operation_timeout;
 185     co->session_timeout = session_timeout;
 186
 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_END:
 220             {
 221                 const char *error, *addinfo;
 222                 int err;
 223                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 224                 {
 225                     yaz_log(YLOG_LOG, "Error %s from %s",
 226                             error, client_get_url(cl));
 227                     client_set_diagnostic(cl, err);
 228                     client_set_state(cl, Client_Error);
 229                 }
 230                 else
 231                 {
 232                     iochan_settimeout(iochan, co->session_timeout);
 233                     client_set_state(cl, Client_Idle);
 234                 }
 235                 yaz_cond_broadcast(co->host->cond_ready);
 236             }
 237             break;
 238         case ZOOM_EVENT_SEND_DATA:
 239             break;
 240         case ZOOM_EVENT_RECV_DATA:
 241             break;
 242         case ZOOM_EVENT_UNKNOWN:
 243             break;
 244         case ZOOM_EVENT_SEND_APDU:
 245             client_set_state(co->client, Client_Working);
 246             iochan_settimeout(iochan, co->operation_timeout);
 247             break;
 248         case ZOOM_EVENT_RECV_APDU:
 249             break;
 250         case ZOOM_EVENT_CONNECT:
 251             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 252             co->state = Conn_Open;
 253             break;
 254         case ZOOM_EVENT_RECV_SEARCH:
 255             client_search_response(cl);
 256             break;
 257         case ZOOM_EVENT_RECV_RECORD:
 258             client_record_response(cl);
 259             got_records = 1;
 260             break;
 261         default:
 262             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 263                     ev, client_get_url(cl));
 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         yaz_log(YLOG_WARN, "No task was executed for connection");
 282     iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 283     iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 284 }
 285
 286 static void connection_handler(IOCHAN iochan, int event)
 287 {
 288     struct connection *co = iochan_getdata(iochan);
 289     struct client *cl;
 290     struct host *host = co->host;
 291
 292     yaz_mutex_enter(host->mutex);
 293     cl = co->client;
 294     if (!cl)
 295     {
 296         /* no client associated with it.. We are probably getting
 297            a closed connection from the target.. Or, perhaps, an unexpected
 298            package.. We will just close the connection */
 299         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 300         remove_connection_from_host(co);
 301         yaz_mutex_leave(host->mutex);
 302         connection_destroy(co);
 303     }
 304     else if (event & EVENT_TIMEOUT)
 305     {
 306         if (co->state == Conn_Connecting)
 307         {
 308             yaz_log(YLOG_WARN, "%p connect timeout %s", co, client_get_url(cl));
 309
 310             client_set_state(cl, Client_Error);
 311             remove_connection_from_host(co);
 312             yaz_mutex_leave(host->mutex);
 313             connection_destroy(co);
 314         }
 315         else
 316         {
 317             yaz_log(YLOG_LOG,  "%p Connection idle timeout %s", co, client_get_url(cl));
 318             remove_connection_from_host(co);
 319             yaz_mutex_leave(host->mutex);
 320             connection_destroy(co);
 321         }
 322     }
 323     else
 324     {
 325         yaz_mutex_leave(host->mutex);
 326
 327         client_lock(cl);
 328         non_block_events(co);
 329
 330         ZOOM_connection_fire_event_socket(co->link, event);
 331
 332         non_block_events(co);
 333         client_unlock(cl);
 334
 335         if (co->link)
 336         {
 337             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 338             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 339         }
 340     }
 341 }
 342
 343
 344 // Disassociate connection from client
 345 static void connection_release(struct connection *co)
 346 {
 347     struct client *cl = co->client;
 348
 349     if (!cl)
 350         return;
 351     client_set_connection(cl, 0);
 352     co->client = 0;
 353 }
 354
 355 static struct host *connection_get_host(struct connection *con)
 356 {
 357     return con->host;
 358 }
 359
 360 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 361 {
 362     ZOOM_connection link = 0;
 363     struct host *host = connection_get_host(con);
 364     ZOOM_options zoptions = ZOOM_options_create();
 365     const char *auth;
 366     const char *charset;
 367     const char *sru;
 368     const char *sru_version = 0;
 369
 370     struct session_database *sdb = client_get_database(con->client);
 371     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 372     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 373
 374     assert(con);
 375
 376     ZOOM_options_set(zoptions, "async", "1");
 377     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 378     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 379
 380     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 381         ZOOM_options_set(zoptions, "charset", charset);
 382
 383     if (zproxy && *zproxy)
 384     {
 385         con->zproxy = xstrdup(zproxy);
 386         ZOOM_options_set(zoptions, "proxy", zproxy);
 387     }
 388     if (apdulog && *apdulog)
 389         ZOOM_options_set(zoptions, "apdulog", apdulog);
 390
 391     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 392         ZOOM_options_set(zoptions, "user", auth);
 393     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 394         ZOOM_options_set(zoptions, "sru", sru);
 395     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 396         && *sru_version)
 397         ZOOM_options_set(zoptions, "sru_version", sru_version);
 398     if (!(link = ZOOM_connection_create(zoptions)))
 399     {
 400         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 401         ZOOM_options_destroy(zoptions);
 402         return -1;
 403     }
 404
 405     if (sru && *sru)
 406     {
 407         char http_hostport[512];
 408         strcpy(http_hostport, "http://");
 409         strcat(http_hostport, host->hostport);
 410         ZOOM_connection_connect(link, http_hostport, 0);
 411     }
 412     else
 413     {
 414         ZOOM_connection_connect(link, host->hostport, 0);
 415     }
 416
 417     con->link = link;
 418     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 419     con->state = Conn_Connecting;
 420     iochan_settimeout(con->iochan, con->operation_timeout);
 421     iochan_setdata(con->iochan, con);
 422     iochan_add(iochan_man, con->iochan);
 423
 424     /* this fragment is bad DRY: from client_prep_connection */
 425     client_set_state(con->client, Client_Connecting);
 426     ZOOM_options_destroy(zoptions);
 427     return 0;
 428 }
 429
 430 // Ensure that client has a connection associated
 431 int client_prep_connection(struct client *cl,
 432                            int operation_timeout, int session_timeout,
 433                            iochan_man_t iochan_man,
 434                            const struct timeval *abstime)
 435 {
 436     struct connection *co;
 437     struct session_database *sdb = client_get_database(cl);
 438     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 439     const char *url = session_setting_oneval(sdb, PZ_URL);
 440     struct host *host = 0;
 441
 442     if (zproxy && zproxy[0] == '\0')
 443         zproxy = 0;
 444
 445     if (!url || !*url)
 446         url = sdb->database->id;
 447
 448     host = find_host(client_get_session(cl)->service->server->database_hosts,
 449                      url);
 450
 451     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
 452             client_get_url(cl), url);
 453
 454     co = client_get_connection(cl);
 455
 456     if (co)
 457     {
 458         assert(co->host);
 459         if (co->host == host)
 460             ;  /* reusing connection. It's ours! */
 461         else
 462         {
 463             client_incref(cl);
 464             connection_release(co);
 465             co = 0;
 466         }
 467     }
 468     if (!co)
 469     {
 470         int max_connections = 0;
 471         int reuse_connections = 1;
 472         const char *v = session_setting_oneval(client_get_database(cl),
 473                                                PZ_MAX_CONNECTIONS);
 474         if (v && *v)
 475             max_connections = atoi(v);
 476
 477         v = session_setting_oneval(client_get_database(cl),
 478                 PZ_REUSE_CONNECTIONS);
 479         if (v && *v)
 480             reuse_connections = atoi(v);
 481
 482         // See if someone else has an idle connection
 483         // We should look at timestamps here to select the longest-idle connection
 484         yaz_mutex_enter(host->mutex);
 485         while (1)
 486         {
 487             int num_connections = 0;
 488             for (co = host->connections; co; co = co->next)
 489                 num_connections++;
 490             if (reuse_connections)
 491             {
 492                 for (co = host->connections; co; co = co->next)
 493                 {
 494                     if (connection_is_idle(co) &&
 495                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 496                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 497                                 session_setting_oneval(client_get_database(cl),
 498                                                        PZ_AUTHENTICATION)))
 499                     {
 500                         if (zproxy == 0 && co->zproxy == 0)
 501                             break;
 502                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 503                             break;
 504                     }
 505                 }
 506                 if (co)
 507                 {
 508                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 509                     break;
 510                 }
 511             }
 512             if (max_connections <= 0 || num_connections < max_connections)
 513             {
 514                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 515                         num_connections, max_connections);
 516                 break;
 517             }
 518             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 519                     num_connections, max_connections);
 520             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 521             {
 522                 yaz_log(YLOG_LOG, "out of connections %s", client_get_url(cl));
 523                 client_set_state(cl, Client_Error);
 524                 yaz_mutex_leave(host->mutex);
 525                 return 0;
 526             }
 527         }
 528         if (co)
 529         {
 530             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
 531             connection_release(co);
 532             client_set_connection(cl, co);
 533             co->client = cl;
 534             /* ensure that connection is only assigned to this client
 535                by marking the client non Idle */
 536             client_set_state(cl, Client_Working);
 537             yaz_mutex_leave(host->mutex);
 538             co->operation_timeout = operation_timeout;
 539             co->session_timeout = session_timeout;
 540             /* tells ZOOM to reconnect if necessary. Disabled becuase
 541                the ZOOM_connection_connect flushes the task queue */
 542             ZOOM_connection_connect(co->link, 0, 0);
 543         }
 544         else
 545         {
 546             yaz_mutex_leave(host->mutex);
 547             co = connection_create(cl, host, operation_timeout, session_timeout,
 548                                    iochan_man);
 549         }
 550         assert(co->host);
 551     }
 552
 553     if (co && co->link)
 554         return 1;
 555     else
 556         return 0;
 557 }
 558
 559 /*
 560  * Local variables:
 561  * c-basic-offset: 4
 562  * c-file-style: "Stroustrup"
 563  * indent-tabs-mode: nil
 564  * End:
 565  * vim: shiftwidth=4 tabstop=8 expandtab
 566  */
 567