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 "pazpar2.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 || event == ZOOM_EVENT_END)
  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             return;
 103         }
 104         conp = &(*conp)->next;
 105     }
 106     assert(*conp == 0);
 107 }
 108
 109 // Close connection and recycle structure
 110 void connection_destroy(struct connection *co)
 111 {
 112     if (co->link)
 113     {
 114         ZOOM_connection_destroy(co->link);
 115         iochan_destroy(co->iochan);
 116     }
 117     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 118
 119     remove_connection_from_host(co);
 120     if (co->client)
 121     {
 122         client_disconnect(co->client);
 123     }
 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     new->next = new->host->connections;
 141     new->host->connections = new;
 142     new->client = cl;
 143     new->zproxy = 0;
 144     client_set_connection(cl, new);
 145     new->link = 0;
 146     new->state = Conn_Resolving;
 147     new->operation_timeout = operation_timeout;
 148     new->session_timeout = session_timeout;
 149     if (host->ipport)
 150         connection_connect(new, iochan_man);
 151     return new;
 152 }
 153
 154 static void non_block_events(struct connection *co)
 155 {
 156     struct client *cl = co->client;
 157     IOCHAN iochan = co->iochan;
 158     ZOOM_connection link = co->link;
 159     while (1)
 160     {
 161         int ev;
 162         int r = ZOOM_event_nonblock(1, &link);
 163         if (!r)
 164             break;
 165         ev = ZOOM_connection_last_event(link);
 166 #if 0
 167         yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", ZOOM_get_event_str(ev));
 168 #endif
 169         switch (ev)
 170         {
 171         case ZOOM_EVENT_END:
 172             {
 173                 const char *error, *addinfo;
 174                 int err;
 175                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 176                 {
 177                     yaz_log(YLOG_LOG, "Error %s from %s",
 178                             error, client_get_url(cl));
 179                 }
 180                 iochan_settimeout(iochan, co->session_timeout);
 181                 client_set_diagnostic(cl, err);
 182                 client_set_state(cl, Client_Idle);
 183             }
 184             break;
 185         case ZOOM_EVENT_SEND_DATA:
 186             break;
 187         case ZOOM_EVENT_RECV_DATA:
 188             break;
 189         case ZOOM_EVENT_UNKNOWN:
 190             break;
 191         case ZOOM_EVENT_SEND_APDU:
 192             client_set_state(co->client, Client_Working);
 193             iochan_settimeout(iochan, co->operation_timeout);
 194             break;
 195         case ZOOM_EVENT_RECV_APDU:
 196             break;
 197         case ZOOM_EVENT_CONNECT:
 198             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 199             co->state = Conn_Open;
 200             break;
 201         case ZOOM_EVENT_RECV_SEARCH:
 202             client_search_response(cl);
 203             break;
 204         case ZOOM_EVENT_RECV_RECORD:
 205             client_record_response(cl);
 206             break;
 207         default:
 208             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 209                     ev, client_get_url(cl));
 210         }
 211     }
 212 }
 213
 214 void connection_continue(struct connection *co)
 215 {
 216     non_block_events(co);
 217 }
 218
 219 static void connection_handler(IOCHAN iochan, int event)
 220 {
 221     struct connection *co = iochan_getdata(iochan);
 222     struct client *cl = co->client;
 223     struct session *se = 0;
 224
 225     if (cl)
 226         se = client_get_session(cl);
 227     else
 228     {
 229         connection_destroy(co);
 230         return;
 231     }
 232
 233     if (event & EVENT_TIMEOUT)
 234     {
 235         if (co->state == Conn_Connecting)
 236         {
 237             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 238             client_fatal(cl);
 239         }
 240         else
 241         {
 242             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 243             connection_destroy(co);
 244         }
 245     }
 246     else
 247     {
 248         non_block_events(co);
 249
 250         ZOOM_connection_fire_event_socket(co->link, event);
 251
 252         non_block_events(co);
 253     }
 254 }
 255
 256
 257 // Disassociate connection from client
 258 void connection_release(struct connection *co)
 259 {
 260     struct client *cl = co->client;
 261
 262     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 263     if (!cl)
 264         return;
 265     client_set_connection(cl, 0);
 266     co->client = 0;
 267 }
 268
 269 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 270 {
 271     struct connection *con = host->connections;
 272     while (con)
 273     {
 274         if (con->state == Conn_Resolving)
 275         {
 276             if (!host->ipport) /* unresolved */
 277             {
 278                 connection_destroy(con);
 279                 /* start all over .. at some point it will be NULL */
 280                 con = host->connections;
 281                 continue;
 282             }
 283             else if (!con->client)
 284             {
 285                 connection_destroy(con);
 286                 /* start all over .. at some point it will be NULL */
 287                 con = host->connections;
 288                 continue;
 289             }
 290             else
 291             {
 292                 connection_connect(con, iochan_man);
 293                 client_start_search(con->client);
 294             }
 295         }
 296         else
 297         {
 298             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 299         }
 300         con = con->next;
 301     }
 302 }
 303
 304 static struct host *connection_get_host(struct connection *con)
 305 {
 306     return con->host;
 307 }
 308
 309 // Callback for use by event loop
 310 // We do this because ZOOM connections don't always have (the same) sockets
 311 static int socketfun(IOCHAN c)
 312 {
 313     struct connection *co = iochan_getdata(c);
 314     if (!co->link)
 315         return -1;
 316     return ZOOM_connection_get_socket(co->link);
 317 }
 318
 319 // Because ZOOM always knows what events it is interested in; we may not
 320 static int maskfun(IOCHAN c)
 321 {
 322     struct connection *co = iochan_getdata(c);
 323     if (!co->link)
 324         return 0;
 325
 326     // This is cheating a little, and assuming that eventl mask IDs are always
 327     // the same as ZOOM-C's.
 328     return ZOOM_connection_get_mask(co->link);
 329 }
 330
 331 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 332 {
 333     ZOOM_connection link = 0;
 334     struct host *host = connection_get_host(con);
 335     ZOOM_options zoptions = ZOOM_options_create();
 336     const char *auth;
 337     const char *charset;
 338     const char *sru;
 339     const char *sru_version = 0;
 340
 341     struct session_database *sdb = client_get_database(con->client);
 342     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 343     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 344
 345     assert(host->ipport);
 346     assert(con);
 347
 348     ZOOM_options_set(zoptions, "async", "1");
 349     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 350     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 351
 352     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 353         ZOOM_options_set(zoptions, "charset", charset);
 354
 355     if (zproxy && *zproxy)
 356     {
 357         con->zproxy = xstrdup(zproxy);
 358         ZOOM_options_set(zoptions, "proxy", zproxy);
 359     }
 360     if (apdulog && *apdulog)
 361         ZOOM_options_set(zoptions, "apdulog", apdulog);
 362
 363     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 364         ZOOM_options_set(zoptions, "user", auth);
 365     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 366         ZOOM_options_set(zoptions, "sru", sru);
 367     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 368         && *sru_version)
 369         ZOOM_options_set(zoptions, "sru_version", sru_version);
 370
 371     if (!(link = ZOOM_connection_create(zoptions)))
 372     {
 373         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 374         ZOOM_options_destroy(zoptions);
 375         return -1;
 376     }
 377
 378     if (sru && *sru)
 379     {
 380         char http_hostport[512];
 381         strcpy(http_hostport, "http://");
 382         strcat(http_hostport, host->hostport);
 383         ZOOM_connection_connect(link, http_hostport, 0);
 384     }
 385     else
 386         ZOOM_connection_connect(link, host->ipport, 0);
 387
 388     con->link = link;
 389     con->iochan = iochan_create(0, connection_handler, 0);
 390     con->state = Conn_Connecting;
 391     iochan_settimeout(con->iochan, con->operation_timeout);
 392     iochan_setdata(con->iochan, con);
 393     iochan_setsocketfun(con->iochan, socketfun);
 394     iochan_setmaskfun(con->iochan, maskfun);
 395     iochan_add(iochan_man, con->iochan);
 396
 397     /* this fragment is bad DRY: from client_prep_connection */
 398     client_set_state(con->client, Client_Connecting);
 399     ZOOM_options_destroy(zoptions);
 400     return 0;
 401 }
 402
 403 const char *connection_get_url(struct connection *co)
 404 {
 405     return client_get_url(co->client);
 406 }
 407
 408 // Ensure that client has a connection associated
 409 int client_prep_connection(struct client *cl,
 410                            int operation_timeout, int session_timeout,
 411                            iochan_man_t iochan_man)
 412 {
 413     struct connection *co;
 414     struct session *se = client_get_session(cl);
 415     struct host *host = client_get_host(cl);
 416     struct session_database *sdb = client_get_database(cl);
 417     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 418
 419     if (zproxy && zproxy[0] == '\0')
 420         zproxy = 0;
 421
 422     if (!host)
 423         return 0;
 424
 425     co = client_get_connection(cl);
 426
 427     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 428
 429     if (!co)
 430     {
 431         // See if someone else has an idle connection
 432         // We should look at timestamps here to select the longest-idle connection
 433         for (co = host->connections; co; co = co->next)
 434             if (connection_is_idle(co) &&
 435                 (!co->client || client_get_session(co->client) != se) &&
 436                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 437                         session_setting_oneval(client_get_database(cl),
 438                                                PZ_AUTHENTICATION)))
 439             {
 440                 if (zproxy == 0 && co->zproxy == 0)
 441                     break;
 442                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 443                     break;
 444             }
 445         if (co)
 446         {
 447             connection_release(co);
 448             client_set_connection(cl, co);
 449             co->client = cl;
 450             co->operation_timeout = operation_timeout;
 451             co->session_timeout = session_timeout;
 452             /* tells ZOOM to reconnect if necessary. Disabled becuase
 453                the ZOOM_connection_connect flushes the task queue */
 454             ZOOM_connection_connect(co->link, 0, 0);
 455         }
 456         else
 457         {
 458             co = connection_create(cl, operation_timeout, session_timeout,
 459                                    iochan_man);
 460         }
 461     }
 462
 463     if (co && co->link)
 464         return 1;
 465     else
 466         return 0;
 467 }
 468
 469 /*
 470  * Local variables:
 471  * c-basic-offset: 4
 472  * c-file-style: "Stroustrup"
 473  * indent-tabs-mode: nil
 474  * End:
 475  * vim: shiftwidth=4 tabstop=8 expandtab
 476  */
 477