src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) 2006-2010 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 0
  52 static YAZ_MUTEX g_mutex = 0;
  53 static int no_connections = 0;
  54
  55 static void connection_use(int delta)
  56 {
  57     if (!g_mutex)
  58         yaz_mutex_create(&g_mutex);
  59     yaz_mutex_enter(g_mutex);
  60     no_connections += delta;
  61     yaz_mutex_leave(g_mutex);
  62     yaz_log(YLOG_LOG, "%s connections=%d", delta > 0 ? "INC" : "DEC",
  63             no_connections);
  64 }
  65 #else
  66 #define connection_use(x)
  67 #endif
  68
  69
  70 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  71  */
  72 struct connection {
  73     IOCHAN iochan;
  74     ZOOM_connection link;
  75     struct host *host;
  76     struct client *client;
  77     char *zproxy;
  78     enum {
  79         Conn_Resolving,
  80         Conn_Connecting,
  81         Conn_Open
  82     } state;
  83     int operation_timeout;
  84     int session_timeout;
  85     struct connection *next; // next for same host or next in free list
  86 };
  87
  88 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
  89
  90 static int connection_is_idle(struct connection *co)
  91 {
  92     ZOOM_connection link = co->link;
  93     int event;
  94
  95     if (co->state != Conn_Open || !link)
  96         return 0;
  97
  98     if (!ZOOM_connection_is_idle(link))
  99         return 0;
 100     event = ZOOM_connection_peek_event(link);
 101     if (event == ZOOM_EVENT_NONE)
 102         return 1;
 103     else
 104         return 0;
 105 }
 106
 107 ZOOM_connection connection_get_link(struct connection *co)
 108 {
 109     return co->link;
 110 }
 111
 112 static void remove_connection_from_host(struct connection *con)
 113 {
 114     struct connection **conp = &con->host->connections;
 115     assert(con);
 116     while (*conp)
 117     {
 118         if (*conp == con)
 119         {
 120             *conp = (*conp)->next;
 121             break;
 122         }
 123         conp = &(*conp)->next;
 124     }
 125     yaz_cond_broadcast(con->host->cond_ready);
 126 }
 127
 128 // Close connection and recycle structure
 129 static void connection_destroy(struct connection *co)
 130 {
 131     if (co->link)
 132     {
 133         ZOOM_connection_destroy(co->link);
 134         iochan_destroy(co->iochan);
 135     }
 136     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 137
 138     if (co->client)
 139     {
 140         client_disconnect(co->client);
 141     }
 142
 143     xfree(co->zproxy);
 144     xfree(co);
 145     connection_use(-1);
 146 }
 147
 148 // Creates a new connection for client, associated with the host of
 149 // client's database
 150 static struct connection *connection_create(struct client *cl,
 151                                             int operation_timeout,
 152                                             int session_timeout,
 153                                             iochan_man_t iochan_man)
 154 {
 155     struct connection *co;
 156     struct host *host = client_get_host(cl);
 157
 158     co = xmalloc(sizeof(*co));
 159     co->host = host;
 160
 161     co->client = cl;
 162     co->zproxy = 0;
 163     client_set_connection(cl, co);
 164     co->link = 0;
 165     co->state = Conn_Resolving;
 166     co->operation_timeout = operation_timeout;
 167     co->session_timeout = session_timeout;
 168     if (host->ipport)
 169         connection_connect(co, iochan_man);
 170
 171     yaz_mutex_enter(host->mutex);
 172     co->next = co->host->connections;
 173     co->host->connections = co;
 174     yaz_mutex_leave(host->mutex);
 175
 176     connection_use(1);
 177     return co;
 178 }
 179
 180 static void non_block_events(struct connection *co)
 181 {
 182     int got_records = 0;
 183     IOCHAN iochan = co->iochan;
 184     ZOOM_connection link = co->link;
 185     while (1)
 186     {
 187         struct client *cl = co->client;
 188         int ev;
 189         int r = ZOOM_event_nonblock(1, &link);
 190         if (!r)
 191             break;
 192         if (!cl)
 193             continue;
 194         ev = ZOOM_connection_last_event(link);
 195
 196 #if 1
 197         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
 198 #endif
 199         switch (ev)
 200         {
 201         case ZOOM_EVENT_END:
 202             {
 203                 const char *error, *addinfo;
 204                 int err;
 205                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 206                 {
 207                     yaz_log(YLOG_LOG, "Error %s from %s",
 208                             error, client_get_url(cl));
 209                     client_set_diagnostic(cl, err);
 210                     client_set_state(cl, Client_Error);
 211                 }
 212                 else
 213                 {
 214                     iochan_settimeout(iochan, co->session_timeout);
 215                     client_set_state(cl, Client_Idle);
 216                 }
 217                 yaz_cond_broadcast(co->host->cond_ready);
 218             }
 219             break;
 220         case ZOOM_EVENT_SEND_DATA:
 221             break;
 222         case ZOOM_EVENT_RECV_DATA:
 223             break;
 224         case ZOOM_EVENT_UNKNOWN:
 225             break;
 226         case ZOOM_EVENT_SEND_APDU:
 227             client_set_state(co->client, Client_Working);
 228             iochan_settimeout(iochan, co->operation_timeout);
 229             break;
 230         case ZOOM_EVENT_RECV_APDU:
 231             break;
 232         case ZOOM_EVENT_CONNECT:
 233             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 234             co->state = Conn_Open;
 235             break;
 236         case ZOOM_EVENT_RECV_SEARCH:
 237             client_search_response(cl);
 238             break;
 239         case ZOOM_EVENT_RECV_RECORD:
 240             client_record_response(cl);
 241             got_records = 1;
 242             break;
 243         default:
 244             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 245                     ev, client_get_url(cl));
 246         }
 247     }
 248     if (got_records)
 249     {
 250         struct client *cl = co->client;
 251         if (cl)
 252         {
 253             client_check_preferred_watch(cl);
 254             client_got_records(cl);
 255         }
 256     }
 257 }
 258
 259 void connection_continue(struct connection *co)
 260 {
 261     int r = ZOOM_connection_exec_task(co->link);
 262     if (!r)
 263         yaz_log(YLOG_WARN, "No task was executed for connection");
 264     iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
 265     iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
 266 }
 267
 268 static void connection_handler(IOCHAN iochan, int event)
 269 {
 270     struct connection *co = iochan_getdata(iochan);
 271     struct client *cl;
 272     struct host *host = co->host;
 273
 274     yaz_mutex_enter(host->mutex);
 275     cl = co->client;
 276     if (!cl)
 277     {
 278         /* no client associated with it.. We are probably getting
 279            a closed connection from the target.. Or, perhaps, an unexpected
 280            package.. We will just close the connection */
 281         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 282         remove_connection_from_host(co);
 283         yaz_mutex_leave(host->mutex);
 284         connection_destroy(co);
 285     }
 286     else if (event & EVENT_TIMEOUT)
 287     {
 288         if (co->state == Conn_Connecting)
 289         {
 290             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 291
 292             client_set_state(cl, Client_Error);
 293             connection_destroy(co);
 294         }
 295         else
 296         {
 297             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 298             connection_destroy(co);
 299         }
 300         yaz_mutex_leave(host->mutex);
 301     }
 302     else
 303     {
 304         yaz_mutex_leave(host->mutex);
 305
 306         client_lock(cl);
 307         non_block_events(co);
 308
 309         ZOOM_connection_fire_event_socket(co->link, event);
 310
 311         non_block_events(co);
 312         client_unlock(cl);
 313
 314         if (co->link)
 315         {
 316             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
 317             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
 318         }
 319     }
 320 }
 321
 322
 323 // Disassociate connection from client
 324 static void connection_release(struct connection *co)
 325 {
 326     struct client *cl = co->client;
 327
 328     if (!cl)
 329         return;
 330     client_set_connection(cl, 0);
 331     co->client = 0;
 332 }
 333
 334 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 335 {
 336     struct connection *con;
 337
 338 start:
 339     yaz_mutex_enter(host->mutex);
 340     con = host->connections;
 341     while (con)
 342     {
 343         if (con->state == Conn_Resolving)
 344         {
 345             if (!host->ipport) /* unresolved */
 346             {
 347                 remove_connection_from_host(con);
 348                 yaz_mutex_leave(host->mutex);
 349                 connection_destroy(con);
 350                 goto start;
 351                 /* start all over .. at some point it will be NULL */
 352             }
 353             else if (!con->client)
 354             {
 355                 remove_connection_from_host(con);
 356                 yaz_mutex_leave(host->mutex);
 357                 connection_destroy(con);
 358                 /* start all over .. at some point it will be NULL */
 359                 goto start;
 360             }
 361             else
 362             {
 363                 yaz_mutex_leave(host->mutex);
 364                 connection_connect(con, iochan_man);
 365                 client_start_search(con->client);
 366                 goto start;
 367             }
 368         }
 369         else
 370         {
 371             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 372             con = con->next;
 373         }
 374     }
 375     yaz_mutex_leave(host->mutex);
 376 }
 377
 378 static struct host *connection_get_host(struct connection *con)
 379 {
 380     return con->host;
 381 }
 382
 383 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 384 {
 385     ZOOM_connection link = 0;
 386     struct host *host = connection_get_host(con);
 387     ZOOM_options zoptions = ZOOM_options_create();
 388     const char *auth;
 389     const char *charset;
 390     const char *sru;
 391     const char *sru_version = 0;
 392
 393     struct session_database *sdb = client_get_database(con->client);
 394     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 395     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 396
 397     assert(host->ipport);
 398     assert(con);
 399
 400     ZOOM_options_set(zoptions, "async", "1");
 401     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 402     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 403
 404     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 405         ZOOM_options_set(zoptions, "charset", charset);
 406
 407     if (zproxy && *zproxy)
 408     {
 409         con->zproxy = xstrdup(zproxy);
 410         ZOOM_options_set(zoptions, "proxy", zproxy);
 411     }
 412     if (apdulog && *apdulog)
 413         ZOOM_options_set(zoptions, "apdulog", apdulog);
 414
 415     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 416         ZOOM_options_set(zoptions, "user", auth);
 417     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 418         ZOOM_options_set(zoptions, "sru", sru);
 419     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 420         && *sru_version)
 421         ZOOM_options_set(zoptions, "sru_version", sru_version);
 422
 423     if (!(link = ZOOM_connection_create(zoptions)))
 424     {
 425         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 426         ZOOM_options_destroy(zoptions);
 427         return -1;
 428     }
 429
 430     if (sru && *sru)
 431     {
 432         char http_hostport[512];
 433         strcpy(http_hostport, "http://");
 434         strcat(http_hostport, host->hostport);
 435         ZOOM_connection_connect(link, http_hostport, 0);
 436     }
 437     else if (zproxy && *zproxy)
 438         ZOOM_connection_connect(link, host->hostport, 0);
 439     else
 440         ZOOM_connection_connect(link, host->ipport, 0);
 441
 442     con->link = link;
 443     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
 444     con->state = Conn_Connecting;
 445     iochan_settimeout(con->iochan, con->operation_timeout);
 446     iochan_setdata(con->iochan, con);
 447     iochan_add(iochan_man, con->iochan);
 448
 449     /* this fragment is bad DRY: from client_prep_connection */
 450     client_set_state(con->client, Client_Connecting);
 451     ZOOM_options_destroy(zoptions);
 452     return 0;
 453 }
 454
 455 // Ensure that client has a connection associated
 456 int client_prep_connection(struct client *cl,
 457                            int operation_timeout, int session_timeout,
 458                            iochan_man_t iochan_man,
 459                            const struct timeval *abstime)
 460 {
 461     struct connection *co;
 462     struct host *host = client_get_host(cl);
 463     struct session_database *sdb = client_get_database(cl);
 464     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 465
 466     if (zproxy && zproxy[0] == '\0')
 467         zproxy = 0;
 468
 469     if (!host)
 470         return 0;
 471
 472     co = client_get_connection(cl);
 473
 474     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 475
 476     if (!co)
 477     {
 478         int max_connections = 0;
 479         int reuse_connections = 1;
 480         const char *v = session_setting_oneval(client_get_database(cl),
 481                                                PZ_MAX_CONNECTIONS);
 482         if (v && *v)
 483             max_connections = atoi(v);
 484
 485         v = session_setting_oneval(client_get_database(cl),
 486                 PZ_REUSE_CONNECTIONS);
 487         if (v && *v)
 488             reuse_connections = atoi(v);
 489
 490         // See if someone else has an idle connection
 491         // We should look at timestamps here to select the longest-idle connection
 492         yaz_mutex_enter(host->mutex);
 493         while (1)
 494         {
 495             int num_connections = 0;
 496             for (co = host->connections; co; co = co->next)
 497                 num_connections++;
 498             if (reuse_connections) {
 499                 for (co = host->connections; co; co = co->next)
 500                 {
 501                     if (connection_is_idle(co) &&
 502                         (!co->client || client_get_state(co->client) == Client_Idle) &&
 503                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
 504                                 session_setting_oneval(client_get_database(cl),
 505                                                        PZ_AUTHENTICATION)))
 506                     {
 507                         if (zproxy == 0 && co->zproxy == 0)
 508                             break;
 509                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 510                             break;
 511                     }
 512                 }
 513                 if (co)
 514                 {
 515                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
 516                     break;
 517                 }
 518             }
 519             if (max_connections <= 0 || num_connections < max_connections)
 520             {
 521                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
 522                         num_connections, max_connections);
 523                 break;
 524             }
 525             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
 526                     num_connections, max_connections);
 527             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
 528             {
 529                 yaz_log(YLOG_LOG, "out of connections %s", client_get_url(cl));
 530                 client_set_state(cl, Client_Error);
 531                 yaz_mutex_leave(host->mutex);
 532                 return 0;
 533             }
 534         }
 535         if (co)
 536         {
 537             connection_release(co);
 538             client_set_connection(cl, co);
 539             co->client = cl;
 540             /* ensure that connection is only assigned to this client
 541                by marking the client non Idle */
 542             client_set_state(cl, Client_Working);
 543             yaz_mutex_leave(host->mutex);
 544             co->operation_timeout = operation_timeout;
 545             co->session_timeout = session_timeout;
 546             /* tells ZOOM to reconnect if necessary. Disabled becuase
 547                the ZOOM_connection_connect flushes the task queue */
 548             ZOOM_connection_connect(co->link, 0, 0);
 549         }
 550         else
 551         {
 552             yaz_mutex_leave(host->mutex);
 553             co = connection_create(cl, operation_timeout, session_timeout,
 554                                    iochan_man);
 555         }
 556     }
 557
 558     if (co && co->link)
 559         return 1;
 560     else
 561         return 0;
 562 }
 563
 564 /*
 565  * Local variables:
 566  * c-basic-offset: 4
 567  * c-file-style: "Stroustrup"
 568  * indent-tabs-mode: nil
 569  * End:
 570  * vim: shiftwidth=4 tabstop=8 expandtab
 571  */
 572