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 }
 126
 127 // Close connection and recycle structure
 128 static void connection_destroy(struct connection *co)
 129 {
 130     if (co->link)
 131     {
 132         ZOOM_connection_destroy(co->link);
 133         iochan_destroy(co->iochan);
 134     }
 135     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 136
 137     if (co->client)
 138     {
 139         client_disconnect(co->client);
 140     }
 141
 142     remove_connection_from_host(co);
 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 0
 197         yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", 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                 }
 210                 iochan_settimeout(iochan, co->session_timeout);
 211                 client_set_diagnostic(cl, err);
 212                 client_set_state(cl, Client_Idle);
 213             }
 214             break;
 215         case ZOOM_EVENT_SEND_DATA:
 216             break;
 217         case ZOOM_EVENT_RECV_DATA:
 218             break;
 219         case ZOOM_EVENT_UNKNOWN:
 220             break;
 221         case ZOOM_EVENT_SEND_APDU:
 222             client_set_state(co->client, Client_Working);
 223             iochan_settimeout(iochan, co->operation_timeout);
 224             break;
 225         case ZOOM_EVENT_RECV_APDU:
 226             break;
 227         case ZOOM_EVENT_CONNECT:
 228             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 229             co->state = Conn_Open;
 230             break;
 231         case ZOOM_EVENT_RECV_SEARCH:
 232             client_search_response(cl);
 233             break;
 234         case ZOOM_EVENT_RECV_RECORD:
 235             client_record_response(cl);
 236             got_records = 1;
 237             break;
 238         default:
 239             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 240                     ev, client_get_url(cl));
 241         }
 242     }
 243     if (got_records)
 244     {
 245         struct client *cl = co->client;
 246         if (cl)
 247         {
 248             client_got_records(cl);
 249         }
 250     }
 251 }
 252
 253 void connection_continue(struct connection *co)
 254 {
 255     int r = ZOOM_connection_exec_task(co->link);
 256     if (!r)
 257         yaz_log(YLOG_WARN, "No task was executed for connection");
 258 }
 259
 260 static void connection_handler(IOCHAN iochan, int event)
 261 {
 262     struct connection *co = iochan_getdata(iochan);
 263     struct client *cl;
 264     struct host *host = co->host;
 265
 266     yaz_mutex_enter(host->mutex);
 267     cl = co->client;
 268     if (!cl)
 269     {
 270         /* no client associated with it.. We are probably getting
 271            a closed connection from the target.. Or, perhaps, an unexpected
 272            package.. We will just close the connection */
 273         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
 274         connection_destroy(co);
 275         yaz_mutex_leave(host->mutex);
 276     }
 277     else if (event & EVENT_TIMEOUT)
 278     {
 279         if (co->state == Conn_Connecting)
 280         {
 281             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 282
 283             client_set_state(cl, Client_Error);
 284             connection_destroy(co);
 285         }
 286         else if (client_get_state(co->client) == Client_Idle)
 287         {
 288             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 289             connection_destroy(co);
 290         }
 291         else
 292         {
 293             yaz_log(YLOG_LOG,  "ignore timeout %s", client_get_url(cl));
 294         }
 295         yaz_mutex_leave(host->mutex);
 296     }
 297     else
 298     {
 299         yaz_mutex_leave(host->mutex);
 300
 301         client_lock(cl);
 302         non_block_events(co);
 303
 304         ZOOM_connection_fire_event_socket(co->link, event);
 305
 306         non_block_events(co);
 307         client_unlock(cl);
 308     }
 309 }
 310
 311
 312 // Disassociate connection from client
 313 static void connection_release(struct connection *co)
 314 {
 315     struct client *cl = co->client;
 316
 317     if (!cl)
 318         return;
 319     client_set_connection(cl, 0);
 320     co->client = 0;
 321 }
 322
 323 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 324 {
 325     struct connection *con;
 326
 327 start:
 328     yaz_mutex_enter(host->mutex);
 329     con = host->connections;
 330     while (con)
 331     {
 332         if (con->state == Conn_Resolving)
 333         {
 334             if (!host->ipport) /* unresolved */
 335             {
 336                 yaz_mutex_leave(host->mutex);
 337                 connection_destroy(con);
 338                 goto start;
 339                 /* start all over .. at some point it will be NULL */
 340             }
 341             else if (!con->client)
 342             {
 343                 yaz_mutex_leave(host->mutex);
 344                 connection_destroy(con);
 345                 /* start all over .. at some point it will be NULL */
 346                 goto start;
 347             }
 348             else
 349             {
 350                 yaz_mutex_leave(host->mutex);
 351                 connection_connect(con, iochan_man);
 352                 client_start_search(con->client);
 353                 goto start;
 354             }
 355         }
 356         else
 357         {
 358             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 359             con = con->next;
 360         }
 361     }
 362     yaz_mutex_leave(host->mutex);
 363 }
 364
 365 static struct host *connection_get_host(struct connection *con)
 366 {
 367     return con->host;
 368 }
 369
 370 // Callback for use by event loop
 371 // We do this because ZOOM connections don't always have (the same) sockets
 372 static int socketfun(IOCHAN c)
 373 {
 374     struct connection *co = iochan_getdata(c);
 375     if (!co->link)
 376         return -1;
 377     return ZOOM_connection_get_socket(co->link);
 378 }
 379
 380 // Because ZOOM always knows what events it is interested in; we may not
 381 static int maskfun(IOCHAN c)
 382 {
 383     struct connection *co = iochan_getdata(c);
 384     if (!co->link)
 385         return 0;
 386
 387     // This is cheating a little, and assuming that eventl mask IDs are always
 388     // the same as ZOOM-C's.
 389     return ZOOM_connection_get_mask(co->link);
 390 }
 391
 392 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 393 {
 394     ZOOM_connection link = 0;
 395     struct host *host = connection_get_host(con);
 396     ZOOM_options zoptions = ZOOM_options_create();
 397     const char *auth;
 398     const char *charset;
 399     const char *sru;
 400     const char *sru_version = 0;
 401
 402     struct session_database *sdb = client_get_database(con->client);
 403     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 404     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 405
 406     assert(host->ipport);
 407     assert(con);
 408
 409     ZOOM_options_set(zoptions, "async", "1");
 410     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 411     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 412
 413     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 414         ZOOM_options_set(zoptions, "charset", charset);
 415
 416     if (zproxy && *zproxy)
 417     {
 418         con->zproxy = xstrdup(zproxy);
 419         ZOOM_options_set(zoptions, "proxy", zproxy);
 420     }
 421     if (apdulog && *apdulog)
 422         ZOOM_options_set(zoptions, "apdulog", apdulog);
 423
 424     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 425         ZOOM_options_set(zoptions, "user", auth);
 426     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 427         ZOOM_options_set(zoptions, "sru", sru);
 428     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 429         && *sru_version)
 430         ZOOM_options_set(zoptions, "sru_version", sru_version);
 431
 432     if (!(link = ZOOM_connection_create(zoptions)))
 433     {
 434         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 435         ZOOM_options_destroy(zoptions);
 436         return -1;
 437     }
 438
 439     if (sru && *sru)
 440     {
 441         char http_hostport[512];
 442         strcpy(http_hostport, "http://");
 443         strcat(http_hostport, host->hostport);
 444         ZOOM_connection_connect(link, http_hostport, 0);
 445     }
 446     else
 447         ZOOM_connection_connect(link, host->ipport, 0);
 448
 449     con->link = link;
 450     con->iochan = iochan_create(0, connection_handler, 0, "connection_socket");
 451     con->state = Conn_Connecting;
 452     iochan_settimeout(con->iochan, con->operation_timeout);
 453     iochan_setdata(con->iochan, con);
 454     iochan_setsocketfun(con->iochan, socketfun);
 455     iochan_setmaskfun(con->iochan, maskfun);
 456     iochan_add(iochan_man, con->iochan);
 457
 458     /* this fragment is bad DRY: from client_prep_connection */
 459     client_set_state(con->client, Client_Connecting);
 460     ZOOM_options_destroy(zoptions);
 461     return 0;
 462 }
 463
 464 // Ensure that client has a connection associated
 465 int client_prep_connection(struct client *cl,
 466                            int operation_timeout, int session_timeout,
 467                            iochan_man_t iochan_man)
 468 {
 469     struct connection *co;
 470     struct host *host = client_get_host(cl);
 471     struct session_database *sdb = client_get_database(cl);
 472     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 473
 474     if (zproxy && zproxy[0] == '\0')
 475         zproxy = 0;
 476
 477     if (!host)
 478         return 0;
 479
 480     co = client_get_connection(cl);
 481
 482     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 483
 484     if (!co)
 485     {
 486         // See if someone else has an idle connection
 487         // We should look at timestamps here to select the longest-idle connection
 488         yaz_mutex_enter(host->mutex);
 489         for (co = host->connections; co; co = co->next)
 490             if (connection_is_idle(co) &&
 491                 (!co->client || client_get_state(co->client) == Client_Idle) &&
 492                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 493                         session_setting_oneval(client_get_database(cl),
 494                                                PZ_AUTHENTICATION)))
 495             {
 496                 if (zproxy == 0 && co->zproxy == 0)
 497                     break;
 498                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 499                     break;
 500             }
 501         if (co)
 502         {
 503             connection_release(co);
 504             client_set_connection(cl, co);
 505             co->client = cl;
 506             /* ensure that connection is only assigned to this client
 507                by marking the client non Idle */
 508             client_set_state(cl, Client_Working);
 509             yaz_mutex_leave(host->mutex);
 510             co->operation_timeout = operation_timeout;
 511             co->session_timeout = session_timeout;
 512             /* tells ZOOM to reconnect if necessary. Disabled becuase
 513                the ZOOM_connection_connect flushes the task queue */
 514             ZOOM_connection_connect(co->link, 0, 0);
 515         }
 516         else
 517         {
 518             yaz_mutex_leave(host->mutex);
 519             co = connection_create(cl, operation_timeout, session_timeout,
 520                                    iochan_man);
 521         }
 522     }
 523
 524     if (co && co->link)
 525         return 1;
 526     else
 527         return 0;
 528 }
 529
 530 /*
 531  * Local variables:
 532  * c-basic-offset: 4
 533  * c-file-style: "Stroustrup"
 534  * indent-tabs-mode: nil
 535  * End:
 536  * vim: shiftwidth=4 tabstop=8 expandtab
 537  */
 538