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