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 *ibuf;
  59     int ibufsize;
  60     char *zproxy;
  61     enum {
  62         Conn_Resolving,
  63         Conn_Connecting,
  64         Conn_Open
  65     } state;
  66     int operation_timeout;
  67     int session_timeout;
  68     struct connection *next; // next for same host or next in free list
  69 };
  70
  71 static struct connection *connection_freelist = 0; /* thread pr */
  72
  73 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
  74
  75 static int connection_is_idle(struct connection *co)
  76 {
  77     ZOOM_connection link = co->link;
  78     int event;
  79
  80     if (co->state != Conn_Open || !link)
  81         return 0;
  82
  83     if (!ZOOM_connection_is_idle(link))
  84         return 0;
  85     event = ZOOM_connection_peek_event(link);
  86     if (event == ZOOM_EVENT_NONE || event == ZOOM_EVENT_END)
  87         return 1;
  88     else
  89         return 0;
  90 }
  91
  92 ZOOM_connection connection_get_link(struct connection *co)
  93 {
  94     return co->link;
  95 }
  96
  97 static void remove_connection_from_host(struct connection *con)
  98 {
  99     struct connection **conp = &con->host->connections;
 100     assert(con);
 101     while (*conp)
 102     {
 103         if (*conp == con)
 104         {
 105             *conp = (*conp)->next;
 106             return;
 107         }
 108         conp = &(*conp)->next;
 109     }
 110     assert(*conp == 0);
 111 }
 112
 113 // Close connection and recycle structure
 114 void connection_destroy(struct connection *co)
 115 {
 116     if (co->link)
 117     {
 118         ZOOM_connection_destroy(co->link);
 119         iochan_destroy(co->iochan);
 120     }
 121     yaz_log(YLOG_DEBUG, "Connection destroy %s", co->host->hostport);
 122
 123     remove_connection_from_host(co);
 124     if (co->client)
 125     {
 126         client_disconnect(co->client);
 127     }
 128     xfree(co->zproxy);
 129     co->zproxy = 0;
 130     co->next = connection_freelist;
 131     connection_freelist = co;
 132 }
 133
 134 // Creates a new connection for client, associated with the host of
 135 // client's database
 136 static struct connection *connection_create(struct client *cl,
 137                                             int operation_timeout,
 138                                             int session_timeout,
 139                                             iochan_man_t iochan_man)
 140 {
 141     struct connection *new;
 142     struct host *host = client_get_host(cl);
 143
 144     if ((new = connection_freelist))
 145         connection_freelist = new->next;
 146     else
 147     {
 148         new = xmalloc(sizeof (struct connection));
 149         new->ibuf = 0;
 150         new->ibufsize = 0;
 151     }
 152     new->host = host;
 153     new->next = new->host->connections;
 154     new->host->connections = new;
 155     new->client = cl;
 156     new->zproxy = 0;
 157     client_set_connection(cl, new);
 158     new->link = 0;
 159     new->state = Conn_Resolving;
 160     new->operation_timeout = operation_timeout;
 161     new->session_timeout = session_timeout;
 162     if (host->ipport)
 163         connection_connect(new, iochan_man);
 164     return new;
 165 }
 166
 167 static void non_block_events(struct connection *co)
 168 {
 169     struct client *cl = co->client;
 170     IOCHAN iochan = co->iochan;
 171     ZOOM_connection link = co->link;
 172     while (1)
 173     {
 174         int ev;
 175         int r = ZOOM_event_nonblock(1, &link);
 176         if (!r)
 177             break;
 178         ev = ZOOM_connection_last_event(link);
 179 #if 0
 180         yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", ZOOM_get_event_str(ev));
 181 #endif
 182         switch (ev)
 183         {
 184         case ZOOM_EVENT_END:
 185             {
 186                 const char *error, *addinfo;
 187                 int err;
 188                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 189                 {
 190                     yaz_log(YLOG_LOG, "Error %s from %s",
 191                             error, client_get_url(cl));
 192                 }
 193                 iochan_settimeout(iochan, co->session_timeout);
 194                 client_set_diagnostic(cl, err);
 195                 client_set_state(cl, Client_Idle);
 196             }
 197             break;
 198         case ZOOM_EVENT_SEND_DATA:
 199             break;
 200         case ZOOM_EVENT_RECV_DATA:
 201             break;
 202         case ZOOM_EVENT_UNKNOWN:
 203             break;
 204         case ZOOM_EVENT_SEND_APDU:
 205             client_set_state(co->client, Client_Working);
 206             iochan_settimeout(iochan, co->operation_timeout);
 207             break;
 208         case ZOOM_EVENT_RECV_APDU:
 209             break;
 210         case ZOOM_EVENT_CONNECT:
 211             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 212             co->state = Conn_Open;
 213             break;
 214         case ZOOM_EVENT_RECV_SEARCH:
 215             client_search_response(cl);
 216             break;
 217         case ZOOM_EVENT_RECV_RECORD:
 218             client_record_response(cl);
 219             break;
 220         default:
 221             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 222                     ev, client_get_url(cl));
 223         }
 224     }
 225 }
 226
 227 void connection_continue(struct connection *co)
 228 {
 229     non_block_events(co);
 230 }
 231
 232 static void connection_handler(IOCHAN iochan, int event)
 233 {
 234     struct connection *co = iochan_getdata(iochan);
 235     struct client *cl = co->client;
 236     struct session *se = 0;
 237
 238     if (cl)
 239         se = client_get_session(cl);
 240     else
 241     {
 242         connection_destroy(co);
 243         return;
 244     }
 245
 246     if (event & EVENT_TIMEOUT)
 247     {
 248         if (co->state == Conn_Connecting)
 249         {
 250             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 251             client_fatal(cl);
 252         }
 253         else
 254         {
 255             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 256             connection_destroy(co);
 257         }
 258     }
 259     else
 260     {
 261         non_block_events(co);
 262
 263         ZOOM_connection_fire_event_socket(co->link, event);
 264
 265         non_block_events(co);
 266     }
 267 }
 268
 269
 270 // Disassociate connection from client
 271 void connection_release(struct connection *co)
 272 {
 273     struct client *cl = co->client;
 274
 275     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 276     if (!cl)
 277         return;
 278     client_set_connection(cl, 0);
 279     co->client = 0;
 280 }
 281
 282 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 283 {
 284     struct connection *con = host->connections;
 285     while (con)
 286     {
 287         if (con->state == Conn_Resolving)
 288         {
 289             if (!host->ipport) /* unresolved */
 290             {
 291                 connection_destroy(con);
 292                 /* start all over .. at some point it will be NULL */
 293                 con = host->connections;
 294                 continue;
 295             }
 296             else if (!con->client)
 297             {
 298                 connection_destroy(con);
 299                 /* start all over .. at some point it will be NULL */
 300                 con = host->connections;
 301                 continue;
 302             }
 303             else
 304             {
 305                 connection_connect(con, iochan_man);
 306                 client_start_search(con->client);
 307             }
 308         }
 309         else
 310         {
 311             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 312         }
 313         con = con->next;
 314     }
 315 }
 316
 317 static struct host *connection_get_host(struct connection *con)
 318 {
 319     return con->host;
 320 }
 321
 322 // Callback for use by event loop
 323 // We do this because ZOOM connections don't always have (the same) sockets
 324 static int socketfun(IOCHAN c)
 325 {
 326     struct connection *co = iochan_getdata(c);
 327     if (!co->link)
 328         return -1;
 329     return ZOOM_connection_get_socket(co->link);
 330 }
 331
 332 // Because ZOOM always knows what events it is interested in; we may not
 333 static int maskfun(IOCHAN c)
 334 {
 335     struct connection *co = iochan_getdata(c);
 336     if (!co->link)
 337         return 0;
 338
 339     // This is cheating a little, and assuming that eventl mask IDs are always
 340     // the same as ZOOM-C's.
 341     return ZOOM_connection_get_mask(co->link);
 342 }
 343
 344 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 345 {
 346     ZOOM_connection link = 0;
 347     struct host *host = connection_get_host(con);
 348     ZOOM_options zoptions = ZOOM_options_create();
 349     const char *auth;
 350     const char *charset;
 351     const char *sru;
 352     const char *sru_version = 0;
 353
 354     struct session_database *sdb = client_get_database(con->client);
 355     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 356     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 357
 358     assert(host->ipport);
 359     assert(con);
 360
 361     ZOOM_options_set(zoptions, "async", "1");
 362     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 363     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 364
 365     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 366         ZOOM_options_set(zoptions, "charset", charset);
 367
 368     if (zproxy && *zproxy)
 369     {
 370         con->zproxy = xstrdup(zproxy);
 371         ZOOM_options_set(zoptions, "proxy", zproxy);
 372     }
 373     if (apdulog && *apdulog)
 374         ZOOM_options_set(zoptions, "apdulog", apdulog);
 375
 376     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 377         ZOOM_options_set(zoptions, "user", auth);
 378     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 379         ZOOM_options_set(zoptions, "sru", sru);
 380     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 381         && *sru_version)
 382         ZOOM_options_set(zoptions, "sru_version", sru_version);
 383
 384     if (!(link = ZOOM_connection_create(zoptions)))
 385     {
 386         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 387         ZOOM_options_destroy(zoptions);
 388         return -1;
 389     }
 390
 391     if (sru && *sru)
 392     {
 393         char http_hostport[512];
 394         strcpy(http_hostport, "http://");
 395         strcat(http_hostport, host->hostport);
 396         ZOOM_connection_connect(link, http_hostport, 0);
 397     }
 398     else
 399         ZOOM_connection_connect(link, host->ipport, 0);
 400
 401     con->link = link;
 402     con->iochan = iochan_create(0, connection_handler, 0);
 403     con->state = Conn_Connecting;
 404     iochan_settimeout(con->iochan, con->operation_timeout);
 405     iochan_setdata(con->iochan, con);
 406     iochan_setsocketfun(con->iochan, socketfun);
 407     iochan_setmaskfun(con->iochan, maskfun);
 408     iochan_add(iochan_man, con->iochan);
 409
 410     /* this fragment is bad DRY: from client_prep_connection */
 411     client_set_state(con->client, Client_Connecting);
 412     ZOOM_options_destroy(zoptions);
 413     return 0;
 414 }
 415
 416 const char *connection_get_url(struct connection *co)
 417 {
 418     return client_get_url(co->client);
 419 }
 420
 421 // Ensure that client has a connection associated
 422 int client_prep_connection(struct client *cl,
 423                            int operation_timeout, int session_timeout,
 424                            iochan_man_t iochan_man)
 425 {
 426     struct connection *co;
 427     struct session *se = client_get_session(cl);
 428     struct host *host = client_get_host(cl);
 429     struct session_database *sdb = client_get_database(cl);
 430     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 431
 432     if (zproxy && zproxy[0] == '\0')
 433         zproxy = 0;
 434
 435     if (!host)
 436         return 0;
 437
 438     co = client_get_connection(cl);
 439
 440     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 441
 442     if (!co)
 443     {
 444         // See if someone else has an idle connection
 445         // We should look at timestamps here to select the longest-idle connection
 446         for (co = host->connections; co; co = co->next)
 447             if (connection_is_idle(co) &&
 448                 (!co->client || client_get_session(co->client) != se) &&
 449                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 450                         session_setting_oneval(client_get_database(cl),
 451                                                PZ_AUTHENTICATION)))
 452             {
 453                 if (zproxy == 0 && co->zproxy == 0)
 454                     break;
 455                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 456                     break;
 457             }
 458         if (co)
 459         {
 460             connection_release(co);
 461             client_set_connection(cl, co);
 462             co->client = cl;
 463             co->operation_timeout = operation_timeout;
 464             co->session_timeout = session_timeout;
 465             /* tells ZOOM to reconnect if necessary. Disabled becuase
 466                the ZOOM_connection_connect flushes the task queue */
 467             ZOOM_connection_connect(co->link, 0, 0);
 468         }
 469         else
 470         {
 471             co = connection_create(cl, operation_timeout, session_timeout,
 472                                    iochan_man);
 473         }
 474     }
 475
 476     if (co && co->link)
 477         return 1;
 478     else
 479         return 0;
 480 }
 481
 482 /*
 483  * Local variables:
 484  * c-basic-offset: 4
 485  * c-file-style: "Stroustrup"
 486  * indent-tabs-mode: nil
 487  * End:
 488  * vim: shiftwidth=4 tabstop=8 expandtab
 489  */
 490