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