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     }
 254     else if (event & EVENT_TIMEOUT)
 255     {
 256         if (co->state == Conn_Connecting)
 257         {
 258             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 259
 260             connection_destroy(co);
 261             client_set_state(cl, Client_Error);
 262         }
 263         else if (client_get_state(co->client) == Client_Idle)
 264         {
 265             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 266             connection_destroy(co);
 267         }
 268         else
 269         {
 270             yaz_log(YLOG_LOG,  "ignore timeout %s", client_get_url(cl));
 271         }
 272     }
 273     else
 274     {
 275         non_block_events(co);
 276
 277         ZOOM_connection_fire_event_socket(co->link, event);
 278
 279         non_block_events(co);
 280     }
 281     yaz_mutex_leave(host->mutex);
 282 }
 283
 284
 285 // Disassociate connection from client
 286 void connection_release(struct connection *co)
 287 {
 288     struct client *cl = co->client;
 289
 290     if (!cl)
 291         return;
 292     client_set_connection(cl, 0);
 293     co->client = 0;
 294 }
 295
 296 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 297 {
 298     struct connection *con;
 299
 300 start:
 301     yaz_mutex_enter(host->mutex);
 302     con = host->connections;
 303     while (con)
 304     {
 305         if (con->state == Conn_Resolving)
 306         {
 307             if (!host->ipport) /* unresolved */
 308             {
 309                 yaz_mutex_leave(host->mutex);
 310                 connection_destroy(con);
 311                 goto start;
 312                 /* start all over .. at some point it will be NULL */
 313             }
 314             else if (!con->client)
 315             {
 316                 yaz_mutex_leave(host->mutex);
 317                 connection_destroy(con);
 318                 /* start all over .. at some point it will be NULL */
 319                 goto start;
 320             }
 321             else
 322             {
 323                 yaz_mutex_leave(host->mutex);
 324                 connection_connect(con, iochan_man);
 325                 client_start_search(con->client);
 326                 goto start;
 327             }
 328         }
 329         else
 330         {
 331             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 332             con = con->next;
 333         }
 334     }
 335     yaz_mutex_leave(host->mutex);
 336 }
 337
 338 static struct host *connection_get_host(struct connection *con)
 339 {
 340     return con->host;
 341 }
 342
 343 // Callback for use by event loop
 344 // We do this because ZOOM connections don't always have (the same) sockets
 345 static int socketfun(IOCHAN c)
 346 {
 347     struct connection *co = iochan_getdata(c);
 348     if (!co->link)
 349         return -1;
 350     return ZOOM_connection_get_socket(co->link);
 351 }
 352
 353 // Because ZOOM always knows what events it is interested in; we may not
 354 static int maskfun(IOCHAN c)
 355 {
 356     struct connection *co = iochan_getdata(c);
 357     if (!co->link)
 358         return 0;
 359
 360     // This is cheating a little, and assuming that eventl mask IDs are always
 361     // the same as ZOOM-C's.
 362     return ZOOM_connection_get_mask(co->link);
 363 }
 364
 365 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 366 {
 367     ZOOM_connection link = 0;
 368     struct host *host = connection_get_host(con);
 369     ZOOM_options zoptions = ZOOM_options_create();
 370     const char *auth;
 371     const char *charset;
 372     const char *sru;
 373     const char *sru_version = 0;
 374
 375     struct session_database *sdb = client_get_database(con->client);
 376     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 377     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 378
 379     assert(host->ipport);
 380     assert(con);
 381
 382     ZOOM_options_set(zoptions, "async", "1");
 383     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 384     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 385
 386     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 387         ZOOM_options_set(zoptions, "charset", charset);
 388
 389     if (zproxy && *zproxy)
 390     {
 391         con->zproxy = xstrdup(zproxy);
 392         ZOOM_options_set(zoptions, "proxy", zproxy);
 393     }
 394     if (apdulog && *apdulog)
 395         ZOOM_options_set(zoptions, "apdulog", apdulog);
 396
 397     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 398         ZOOM_options_set(zoptions, "user", auth);
 399     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 400         ZOOM_options_set(zoptions, "sru", sru);
 401     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 402         && *sru_version)
 403         ZOOM_options_set(zoptions, "sru_version", sru_version);
 404
 405     if (!(link = ZOOM_connection_create(zoptions)))
 406     {
 407         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 408         ZOOM_options_destroy(zoptions);
 409         return -1;
 410     }
 411
 412     if (sru && *sru)
 413     {
 414         char http_hostport[512];
 415         strcpy(http_hostport, "http://");
 416         strcat(http_hostport, host->hostport);
 417         ZOOM_connection_connect(link, http_hostport, 0);
 418     }
 419     else
 420         ZOOM_connection_connect(link, host->ipport, 0);
 421
 422     con->link = link;
 423     con->iochan = iochan_create(0, connection_handler, 0, "connection_socket");
 424     con->state = Conn_Connecting;
 425     iochan_settimeout(con->iochan, con->operation_timeout);
 426     iochan_setdata(con->iochan, con);
 427     iochan_setsocketfun(con->iochan, socketfun);
 428     iochan_setmaskfun(con->iochan, maskfun);
 429     iochan_add(iochan_man, con->iochan);
 430
 431     /* this fragment is bad DRY: from client_prep_connection */
 432     client_set_state(con->client, Client_Connecting);
 433     ZOOM_options_destroy(zoptions);
 434     return 0;
 435 }
 436
 437 const char *connection_get_url(struct connection *co)
 438 {
 439     return client_get_url(co->client);
 440 }
 441
 442 // Ensure that client has a connection associated
 443 int client_prep_connection(struct client *cl,
 444                            int operation_timeout, int session_timeout,
 445                            iochan_man_t iochan_man)
 446 {
 447     struct connection *co;
 448     struct host *host = client_get_host(cl);
 449     struct session_database *sdb = client_get_database(cl);
 450     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 451
 452     if (zproxy && zproxy[0] == '\0')
 453         zproxy = 0;
 454
 455     if (!host)
 456         return 0;
 457
 458     co = client_get_connection(cl);
 459
 460     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 461
 462     if (!co)
 463     {
 464         // See if someone else has an idle connection
 465         // We should look at timestamps here to select the longest-idle connection
 466         yaz_mutex_enter(host->mutex);
 467         for (co = host->connections; co; co = co->next)
 468             if (connection_is_idle(co) &&
 469                 (!co->client || client_get_state(co->client) == Client_Idle) &&
 470                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 471                         session_setting_oneval(client_get_database(cl),
 472                                                PZ_AUTHENTICATION)))
 473             {
 474                 if (zproxy == 0 && co->zproxy == 0)
 475                     break;
 476                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 477                     break;
 478             }
 479         if (co)
 480         {
 481             connection_release(co);
 482             client_set_connection(cl, co);
 483             co->client = cl;
 484             /* ensure that connection is only assigned to this client
 485                by marking the client non Idle */
 486             client_set_state(cl, Client_Working);
 487             yaz_mutex_leave(host->mutex);
 488             co->operation_timeout = operation_timeout;
 489             co->session_timeout = session_timeout;
 490             /* tells ZOOM to reconnect if necessary. Disabled becuase
 491                the ZOOM_connection_connect flushes the task queue */
 492             ZOOM_connection_connect(co->link, 0, 0);
 493         }
 494         else
 495         {
 496             yaz_mutex_leave(host->mutex);
 497             co = connection_create(cl, operation_timeout, session_timeout,
 498                                    iochan_man);
 499         }
 500     }
 501
 502     if (co && co->link)
 503         return 1;
 504     else
 505         return 0;
 506 }
 507
 508 /*
 509  * Local variables:
 510  * c-basic-offset: 4
 511  * c-file-style: "Stroustrup"
 512  * indent-tabs-mode: nil
 513  * End:
 514  * vim: shiftwidth=4 tabstop=8 expandtab
 515  */
 516