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