src/connection.c

   1 /* This file is part of Pazpar2.
   2    Copyright (C) 2006-2009 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 "eventl.h"
  46 #include "pazpar2.h"
  47 #include "host.h"
  48 #include "client.h"
  49 #include "settings.h"
  50 #include "parameters.h"
  51
  52
  53 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
  54  */
  55 struct connection {
  56     IOCHAN iochan;
  57     ZOOM_connection link;
  58     struct host *host;
  59     struct client *client;
  60     char *ibuf;
  61     int ibufsize;
  62     char *zproxy;
  63     enum {
  64         Conn_Resolving,
  65         Conn_Connecting,
  66         Conn_Open
  67     } state;
  68     int connect_timeout;
  69     int session_timeout;
  70     struct connection *next; // next for same host or next in free list
  71 };
  72
  73 static struct connection *connection_freelist = 0;
  74
  75 static int connection_connect(struct connection *con);
  76
  77 static int connection_is_idle(struct connection *co)
  78 {
  79     ZOOM_connection link = co->link;
  80     int event;
  81
  82     if (co->state != Conn_Open || !link)
  83         return 0;
  84
  85     if (!ZOOM_connection_is_idle(link))
  86         return 0;
  87     event = ZOOM_connection_peek_event(link);
  88     if (event == ZOOM_EVENT_NONE || event == ZOOM_EVENT_END)
  89         return 1;
  90     else
  91         return 0;
  92 }
  93
  94 ZOOM_connection connection_get_link(struct connection *co)
  95 {
  96     return co->link;
  97 }
  98
  99 static void remove_connection_from_host(struct connection *con)
 100 {
 101     struct connection **conp = &con->host->connections;
 102     assert(con);
 103     while (*conp)
 104     {
 105         if (*conp == con)
 106         {
 107             *conp = (*conp)->next;
 108             return;
 109         }
 110         conp = &(*conp)->next;
 111     }
 112     assert(*conp == 0);
 113 }
 114
 115 // Close connection and recycle structure
 116 void connection_destroy(struct connection *co)
 117 {
 118     if (co->link)
 119     {
 120         ZOOM_connection_destroy(co->link);
 121         iochan_destroy(co->iochan);
 122     }
 123     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 124
 125     remove_connection_from_host(co);
 126     if (co->client)
 127     {
 128         client_disconnect(co->client);
 129     }
 130     xfree(co->zproxy);
 131     co->zproxy = 0;
 132     co->next = connection_freelist;
 133     connection_freelist = co;
 134 }
 135
 136 // Creates a new connection for client, associated with the host of
 137 // client's database
 138 static struct connection *connection_create(struct client *cl,
 139                                             int connect_timeout,
 140                                             int session_timeout)
 141 {
 142     struct connection *new;
 143     struct host *host = client_get_host(cl);
 144
 145     if ((new = connection_freelist))
 146         connection_freelist = new->next;
 147     else
 148     {
 149         new = xmalloc(sizeof (struct connection));
 150         new->ibuf = 0;
 151         new->ibufsize = 0;
 152     }
 153     new->host = host;
 154     new->next = new->host->connections;
 155     new->host->connections = new;
 156     new->client = cl;
 157     new->zproxy = 0;
 158     client_set_connection(cl, new);
 159     new->link = 0;
 160     new->state = Conn_Resolving;
 161     new->connect_timeout = connect_timeout;
 162     new->session_timeout = session_timeout;
 163     if (host->ipport)
 164         connection_connect(new);
 165     return new;
 166 }
 167
 168 static void non_block_events(struct connection *co)
 169 {
 170     struct client *cl = co->client;
 171     IOCHAN iochan = co->iochan;
 172     ZOOM_connection link = co->link;
 173     while (1)
 174     {
 175         int ev;
 176         int r = ZOOM_event_nonblock(1, &link);
 177         if (!r)
 178             break;
 179         ev = ZOOM_connection_last_event(link);
 180 #if 0
 181         yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", ZOOM_get_event_str(ev));
 182 #endif
 183         switch (ev)
 184         {
 185         case ZOOM_EVENT_END:
 186             {
 187                 const char *error, *addinfo;
 188                 if (ZOOM_connection_error(link, &error, &addinfo))
 189                 {
 190                     yaz_log(YLOG_LOG, "Error %s from %s",
 191                             error, client_get_url(cl));
 192                 }
 193                 client_set_state(cl, Client_Idle);
 194             }
 195             break;
 196         case ZOOM_EVENT_SEND_DATA:
 197             break;
 198         case ZOOM_EVENT_RECV_DATA:
 199             break;
 200         case ZOOM_EVENT_UNKNOWN:
 201             break;
 202         case ZOOM_EVENT_SEND_APDU:
 203             client_set_state(co->client, Client_Working);
 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             iochan_settimeout(iochan, co->session_timeout);
 211             break;
 212         case ZOOM_EVENT_RECV_SEARCH:
 213             client_search_response(cl);
 214             break;
 215         case ZOOM_EVENT_RECV_RECORD:
 216             client_record_response(cl);
 217             break;
 218         default:
 219             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 220                     ev, client_get_url(cl));
 221         }
 222     }
 223 }
 224
 225 void connection_continue(struct connection *co)
 226 {
 227     non_block_events(co);
 228 }
 229
 230 static void connection_handler(IOCHAN iochan, int event)
 231 {
 232     struct connection *co = iochan_getdata(iochan);
 233     struct client *cl = co->client;
 234     struct session *se = 0;
 235
 236     if (cl)
 237         se = client_get_session(cl);
 238     else
 239     {
 240         connection_destroy(co);
 241         return;
 242     }
 243
 244     if (event & EVENT_TIMEOUT)
 245     {
 246         if (co->state == Conn_Connecting)
 247         {
 248             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 249             client_fatal(cl);
 250         }
 251         else
 252         {
 253             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 254             connection_destroy(co);
 255         }
 256     }
 257     else
 258     {
 259         non_block_events(co);
 260
 261         ZOOM_connection_fire_event_socket(co->link, event);
 262
 263         non_block_events(co);
 264     }
 265 }
 266
 267
 268 // Disassociate connection from client
 269 void connection_release(struct connection *co)
 270 {
 271     struct client *cl = co->client;
 272
 273     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 274     if (!cl)
 275         return;
 276     client_set_connection(cl, 0);
 277     co->client = 0;
 278 }
 279
 280 void connect_resolver_host(struct host *host)
 281 {
 282     struct connection *con = host->connections;
 283     while (con)
 284     {
 285         if (con->state == Conn_Resolving)
 286         {
 287             if (!host->ipport) /* unresolved */
 288             {
 289                 connection_destroy(con);
 290                 /* start all over .. at some point it will be NULL */
 291                 con = host->connections;
 292                 continue;
 293             }
 294             else if (!con->client)
 295             {
 296                 connection_destroy(con);
 297                 /* start all over .. at some point it will be NULL */
 298                 con = host->connections;
 299                 continue;
 300             }
 301             else
 302             {
 303                 connection_connect(con);
 304                 client_start_search(con->client);
 305             }
 306         }
 307         else
 308         {
 309             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 310         }
 311         con = con->next;
 312     }
 313 }
 314
 315 static struct host *connection_get_host(struct connection *con)
 316 {
 317     return con->host;
 318 }
 319
 320 // Callback for use by event loop
 321 // We do this because ZOOM connections don't always have (the same) sockets
 322 static int socketfun(IOCHAN c)
 323 {
 324     struct connection *co = iochan_getdata(c);
 325     if (!co->link)
 326         return -1;
 327     return ZOOM_connection_get_socket(co->link);
 328 }
 329
 330 // Because ZOOM always knows what events it is interested in; we may not
 331 static int maskfun(IOCHAN c)
 332 {
 333     struct connection *co = iochan_getdata(c);
 334     if (!co->link)
 335         return 0;
 336
 337     // This is cheating a little, and assuming that eventl mask IDs are always
 338     // the same as ZOOM-C's.
 339     return ZOOM_connection_get_mask(co->link);
 340 }
 341
 342 static int connection_connect(struct connection *con)
 343 {
 344     ZOOM_connection link = 0;
 345     struct host *host = connection_get_host(con);
 346     ZOOM_options zoptions = ZOOM_options_create();
 347     const char *auth;
 348     const char *sru;
 349     const char *sru_version = 0;
 350     char ipport[512] = "";
 351
 352     struct session_database *sdb = client_get_database(con->client);
 353     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 354     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 355
 356     assert(host->ipport);
 357     assert(con);
 358
 359     ZOOM_options_set(zoptions, "async", "1");
 360     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 361     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 362     if (zproxy && *zproxy)
 363     {
 364         con->zproxy = xstrdup(zproxy);
 365         ZOOM_options_set(zoptions, "proxy", zproxy);
 366     }
 367     if (apdulog && *apdulog)
 368         ZOOM_options_set(zoptions, "apdulog", apdulog);
 369
 370     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 371         ZOOM_options_set(zoptions, "user", auth);
 372     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 373         ZOOM_options_set(zoptions, "sru", sru);
 374     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 375         && *sru_version)
 376         ZOOM_options_set(zoptions, "sru_version", sru_version);
 377
 378     if (!(link = ZOOM_connection_create(zoptions)))
 379     {
 380         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 381         ZOOM_options_destroy(zoptions);
 382         return -1;
 383     }
 384
 385     if (sru && *sru)
 386         strcpy(ipport, "http://");
 387     strcat(ipport, host->ipport);
 388
 389     ZOOM_connection_connect(link, ipport, 0);
 390
 391     con->link = link;
 392     con->iochan = iochan_create(0, connection_handler, 0);
 393     con->state = Conn_Connecting;
 394     iochan_settimeout(con->iochan, con->connect_timeout);
 395     iochan_setdata(con->iochan, con);
 396     iochan_setsocketfun(con->iochan, socketfun);
 397     iochan_setmaskfun(con->iochan, maskfun);
 398     pazpar2_add_channel(con->iochan);
 399
 400     /* this fragment is bad DRY: from client_prep_connection */
 401     client_set_state(con->client, Client_Connecting);
 402     ZOOM_options_destroy(zoptions);
 403     // This creates the connection
 404     ZOOM_connection_process(link);
 405     return 0;
 406 }
 407
 408 const char *connection_get_url(struct connection *co)
 409 {
 410     return client_get_url(co->client);
 411 }
 412
 413 // Ensure that client has a connection associated
 414 int client_prep_connection(struct client *cl,
 415                            int connect_timeout, int session_timeout)
 416 {
 417     struct connection *co;
 418     struct session *se = client_get_session(cl);
 419     struct host *host = client_get_host(cl);
 420     struct session_database *sdb = client_get_database(cl);
 421     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 422
 423     if (zproxy && zproxy[0] == '\0')
 424         zproxy = 0;
 425
 426     co = client_get_connection(cl);
 427
 428     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 429
 430     if (!co)
 431     {
 432         // See if someone else has an idle connection
 433         // We should look at timestamps here to select the longest-idle connection
 434         for (co = host->connections; co; co = co->next)
 435             if (connection_is_idle(co) &&
 436                 (!co->client || client_get_session(co->client) != se) &&
 437                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 438                         session_setting_oneval(client_get_database(cl),
 439                                                PZ_AUTHENTICATION)))
 440             {
 441                 if (zproxy == 0 && co->zproxy == 0)
 442                     break;
 443                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 444                     break;
 445             }
 446         if (co)
 447         {
 448             connection_release(co);
 449             client_set_connection(cl, co);
 450             co->client = cl;
 451             /* tells ZOOM to reconnect if necessary. Disabled becuase
 452                the ZOOM_connection_connect flushes the task queue */
 453             co->connect_timeout = connect_timeout;
 454             co->session_timeout = session_timeout;
 455             ZOOM_connection_connect(co->link, 0, 0);
 456         }
 457         else
 458         {
 459             co = connection_create(cl, connect_timeout, session_timeout);
 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