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 struct connection *connection_freelist = 0; /* thread pr */
  70
  71 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
  72
  73 static int connection_is_idle(struct connection *co)
  74 {
  75     ZOOM_connection link = co->link;
  76     int event;
  77
  78     if (co->state != Conn_Open || !link)
  79         return 0;
  80
  81     if (!ZOOM_connection_is_idle(link))
  82         return 0;
  83     event = ZOOM_connection_peek_event(link);
  84     if (event == ZOOM_EVENT_NONE || event == ZOOM_EVENT_END)
  85         return 1;
  86     else
  87         return 0;
  88 }
  89
  90 ZOOM_connection connection_get_link(struct connection *co)
  91 {
  92     return co->link;
  93 }
  94
  95 static void remove_connection_from_host(struct connection *con)
  96 {
  97     struct connection **conp = &con->host->connections;
  98     assert(con);
  99     while (*conp)
 100     {
 101         if (*conp == con)
 102         {
 103             *conp = (*conp)->next;
 104             return;
 105         }
 106         conp = &(*conp)->next;
 107     }
 108     assert(*conp == 0);
 109 }
 110
 111 // Close connection and recycle structure
 112 void connection_destroy(struct connection *co)
 113 {
 114     if (co->link)
 115     {
 116         ZOOM_connection_destroy(co->link);
 117         iochan_destroy(co->iochan);
 118     }
 119     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 120
 121     remove_connection_from_host(co);
 122     if (co->client)
 123     {
 124         client_disconnect(co->client);
 125     }
 126     xfree(co->zproxy);
 127     co->zproxy = 0;
 128     co->next = connection_freelist;
 129     connection_freelist = co;
 130 }
 131
 132 // Creates a new connection for client, associated with the host of
 133 // client's database
 134 static struct connection *connection_create(struct client *cl,
 135                                             int operation_timeout,
 136                                             int session_timeout,
 137                                             iochan_man_t iochan_man)
 138 {
 139     struct connection *new;
 140     struct host *host = client_get_host(cl);
 141
 142     if ((new = connection_freelist))
 143         connection_freelist = new->next;
 144     else
 145     {
 146         new = xmalloc(sizeof (struct connection));
 147     }
 148     new->host = host;
 149     new->next = new->host->connections;
 150     new->host->connections = new;
 151     new->client = cl;
 152     new->zproxy = 0;
 153     client_set_connection(cl, new);
 154     new->link = 0;
 155     new->state = Conn_Resolving;
 156     new->operation_timeout = operation_timeout;
 157     new->session_timeout = session_timeout;
 158     if (host->ipport)
 159         connection_connect(new, iochan_man);
 160     return new;
 161 }
 162
 163 static void non_block_events(struct connection *co)
 164 {
 165     struct client *cl = co->client;
 166     IOCHAN iochan = co->iochan;
 167     ZOOM_connection link = co->link;
 168     while (1)
 169     {
 170         int ev;
 171         int r = ZOOM_event_nonblock(1, &link);
 172         if (!r)
 173             break;
 174         ev = ZOOM_connection_last_event(link);
 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             break;
 216         default:
 217             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 218                     ev, client_get_url(cl));
 219         }
 220     }
 221 }
 222
 223 void connection_continue(struct connection *co)
 224 {
 225     non_block_events(co);
 226 }
 227
 228 static void connection_handler(IOCHAN iochan, int event)
 229 {
 230     struct connection *co = iochan_getdata(iochan);
 231     struct client *cl = co->client;
 232     struct session *se = 0;
 233
 234     if (cl)
 235         se = client_get_session(cl);
 236     else
 237     {
 238         connection_destroy(co);
 239         return;
 240     }
 241
 242     if (event & EVENT_TIMEOUT)
 243     {
 244         if (co->state == Conn_Connecting)
 245         {
 246             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 247             client_fatal(cl);
 248         }
 249         else
 250         {
 251             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 252             connection_destroy(co);
 253         }
 254     }
 255     else
 256     {
 257         non_block_events(co);
 258
 259         ZOOM_connection_fire_event_socket(co->link, event);
 260
 261         non_block_events(co);
 262     }
 263 }
 264
 265
 266 // Disassociate connection from client
 267 void connection_release(struct connection *co)
 268 {
 269     struct client *cl = co->client;
 270
 271     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 272     if (!cl)
 273         return;
 274     client_set_connection(cl, 0);
 275     co->client = 0;
 276 }
 277
 278 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 279 {
 280     struct connection *con = host->connections;
 281     while (con)
 282     {
 283         if (con->state == Conn_Resolving)
 284         {
 285             if (!host->ipport) /* unresolved */
 286             {
 287                 connection_destroy(con);
 288                 /* start all over .. at some point it will be NULL */
 289                 con = host->connections;
 290                 continue;
 291             }
 292             else if (!con->client)
 293             {
 294                 connection_destroy(con);
 295                 /* start all over .. at some point it will be NULL */
 296                 con = host->connections;
 297                 continue;
 298             }
 299             else
 300             {
 301                 connection_connect(con, iochan_man);
 302                 client_start_search(con->client);
 303             }
 304         }
 305         else
 306         {
 307             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 308         }
 309         con = con->next;
 310     }
 311 }
 312
 313 static struct host *connection_get_host(struct connection *con)
 314 {
 315     return con->host;
 316 }
 317
 318 // Callback for use by event loop
 319 // We do this because ZOOM connections don't always have (the same) sockets
 320 static int socketfun(IOCHAN c)
 321 {
 322     struct connection *co = iochan_getdata(c);
 323     if (!co->link)
 324         return -1;
 325     return ZOOM_connection_get_socket(co->link);
 326 }
 327
 328 // Because ZOOM always knows what events it is interested in; we may not
 329 static int maskfun(IOCHAN c)
 330 {
 331     struct connection *co = iochan_getdata(c);
 332     if (!co->link)
 333         return 0;
 334
 335     // This is cheating a little, and assuming that eventl mask IDs are always
 336     // the same as ZOOM-C's.
 337     return ZOOM_connection_get_mask(co->link);
 338 }
 339
 340 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 341 {
 342     ZOOM_connection link = 0;
 343     struct host *host = connection_get_host(con);
 344     ZOOM_options zoptions = ZOOM_options_create();
 345     const char *auth;
 346     const char *charset;
 347     const char *sru;
 348     const char *sru_version = 0;
 349
 350     struct session_database *sdb = client_get_database(con->client);
 351     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 352     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 353
 354     assert(host->ipport);
 355     assert(con);
 356
 357     ZOOM_options_set(zoptions, "async", "1");
 358     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 359     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 360
 361     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 362         ZOOM_options_set(zoptions, "charset", charset);
 363
 364     if (zproxy && *zproxy)
 365     {
 366         con->zproxy = xstrdup(zproxy);
 367         ZOOM_options_set(zoptions, "proxy", zproxy);
 368     }
 369     if (apdulog && *apdulog)
 370         ZOOM_options_set(zoptions, "apdulog", apdulog);
 371
 372     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 373         ZOOM_options_set(zoptions, "user", auth);
 374     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 375         ZOOM_options_set(zoptions, "sru", sru);
 376     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 377         && *sru_version)
 378         ZOOM_options_set(zoptions, "sru_version", sru_version);
 379
 380     if (!(link = ZOOM_connection_create(zoptions)))
 381     {
 382         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 383         ZOOM_options_destroy(zoptions);
 384         return -1;
 385     }
 386
 387     if (sru && *sru)
 388     {
 389         char http_hostport[512];
 390         strcpy(http_hostport, "http://");
 391         strcat(http_hostport, host->hostport);
 392         ZOOM_connection_connect(link, http_hostport, 0);
 393     }
 394     else
 395         ZOOM_connection_connect(link, host->ipport, 0);
 396
 397     con->link = link;
 398     con->iochan = iochan_create(0, connection_handler, 0);
 399     con->state = Conn_Connecting;
 400     iochan_settimeout(con->iochan, con->operation_timeout);
 401     iochan_setdata(con->iochan, con);
 402     iochan_setsocketfun(con->iochan, socketfun);
 403     iochan_setmaskfun(con->iochan, maskfun);
 404     iochan_add(iochan_man, con->iochan);
 405
 406     /* this fragment is bad DRY: from client_prep_connection */
 407     client_set_state(con->client, Client_Connecting);
 408     ZOOM_options_destroy(zoptions);
 409     return 0;
 410 }
 411
 412 const char *connection_get_url(struct connection *co)
 413 {
 414     return client_get_url(co->client);
 415 }
 416
 417 // Ensure that client has a connection associated
 418 int client_prep_connection(struct client *cl,
 419                            int operation_timeout, int session_timeout,
 420                            iochan_man_t iochan_man)
 421 {
 422     struct connection *co;
 423     struct session *se = client_get_session(cl);
 424     struct host *host = client_get_host(cl);
 425     struct session_database *sdb = client_get_database(cl);
 426     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 427
 428     if (zproxy && zproxy[0] == '\0')
 429         zproxy = 0;
 430
 431     if (!host)
 432         return 0;
 433
 434     co = client_get_connection(cl);
 435
 436     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 437
 438     if (!co)
 439     {
 440         // See if someone else has an idle connection
 441         // We should look at timestamps here to select the longest-idle connection
 442         for (co = host->connections; co; co = co->next)
 443             if (connection_is_idle(co) &&
 444                 (!co->client || client_get_session(co->client) != se) &&
 445                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 446                         session_setting_oneval(client_get_database(cl),
 447                                                PZ_AUTHENTICATION)))
 448             {
 449                 if (zproxy == 0 && co->zproxy == 0)
 450                     break;
 451                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 452                     break;
 453             }
 454         if (co)
 455         {
 456             connection_release(co);
 457             client_set_connection(cl, co);
 458             co->client = cl;
 459             co->operation_timeout = operation_timeout;
 460             co->session_timeout = session_timeout;
 461             /* tells ZOOM to reconnect if necessary. Disabled becuase
 462                the ZOOM_connection_connect flushes the task queue */
 463             ZOOM_connection_connect(co->link, 0, 0);
 464         }
 465         else
 466         {
 467             co = connection_create(cl, operation_timeout, session_timeout,
 468                                    iochan_man);
 469         }
 470     }
 471
 472     if (co && co->link)
 473         return 1;
 474     else
 475         return 0;
 476 }
 477
 478 /*
 479  * Local variables:
 480  * c-basic-offset: 4
 481  * c-file-style: "Stroustrup"
 482  * indent-tabs-mode: nil
 483  * End:
 484  * vim: shiftwidth=4 tabstop=8 expandtab
 485  */
 486