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     if (co->client)
 121     {
 122         client_disconnect(co->client);
 123     }
 124
 125     remove_connection_from_host(co);
 126     xfree(co->zproxy);
 127     xfree(co);
 128 }
 129
 130 // Creates a new connection for client, associated with the host of
 131 // client's database
 132 static struct connection *connection_create(struct client *cl,
 133                                             int operation_timeout,
 134                                             int session_timeout,
 135                                             iochan_man_t iochan_man)
 136 {
 137     struct connection *new;
 138     struct host *host = client_get_host(cl);
 139
 140     new = xmalloc(sizeof(*new));
 141     new->host = host;
 142
 143     yaz_mutex_enter(host->mutex);
 144     new->next = new->host->connections;
 145     new->host->connections = new;
 146     yaz_mutex_leave(host->mutex);
 147
 148     new->client = cl;
 149     new->zproxy = 0;
 150     client_set_connection(cl, new);
 151     new->link = 0;
 152     new->state = Conn_Resolving;
 153     new->operation_timeout = operation_timeout;
 154     new->session_timeout = session_timeout;
 155     if (host->ipport)
 156         connection_connect(new, iochan_man);
 157     return new;
 158 }
 159
 160 static void non_block_events(struct connection *co)
 161 {
 162     int got_records = 0;
 163     IOCHAN iochan = co->iochan;
 164     ZOOM_connection link = co->link;
 165     while (1)
 166     {
 167         struct client *cl = co->client;
 168         int ev;
 169         int r = ZOOM_event_nonblock(1, &link);
 170         if (!r)
 171             break;
 172         if (!cl)
 173             continue;
 174         ev = ZOOM_connection_last_event(link);
 175
 176         client_incref(cl);
 177 #if 0
 178         yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", ZOOM_get_event_str(ev));
 179 #endif
 180         switch (ev)
 181         {
 182         case ZOOM_EVENT_END:
 183             {
 184                 const char *error, *addinfo;
 185                 int err;
 186                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
 187                 {
 188                     yaz_log(YLOG_LOG, "Error %s from %s",
 189                             error, client_get_url(cl));
 190                 }
 191                 iochan_settimeout(iochan, co->session_timeout);
 192                 client_set_diagnostic(cl, err);
 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             iochan_settimeout(iochan, co->operation_timeout);
 205             break;
 206         case ZOOM_EVENT_RECV_APDU:
 207             break;
 208         case ZOOM_EVENT_CONNECT:
 209             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 210             co->state = Conn_Open;
 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             got_records = 1;
 218             break;
 219         default:
 220             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 221                     ev, client_get_url(cl));
 222         }
 223         client_destroy(cl);
 224     }
 225     if (got_records)
 226     {
 227         struct client *cl = co->client;
 228         if (cl)
 229         {
 230             client_incref(cl);
 231             client_got_records(cl);
 232             client_destroy(cl);
 233         }
 234     }
 235 }
 236
 237 void connection_continue(struct connection *co)
 238 {
 239     non_block_events(co);
 240 }
 241
 242 static void connection_handler(IOCHAN iochan, int event)
 243 {
 244     struct connection *co = iochan_getdata(iochan);
 245     struct client *cl = co->client;
 246
 247     if (!cl)
 248     {
 249         /* no client associated with it.. We are probably getting
 250            a closed connection from the target.. Or, perhaps, an unexpected
 251            package.. We will just close the connection */
 252         connection_destroy(co);
 253         return;
 254     }
 255     if (event & EVENT_TIMEOUT)
 256     {
 257         if (co->state == Conn_Connecting)
 258         {
 259             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 260             client_fatal(cl);
 261         }
 262         else
 263         {
 264             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 265             connection_destroy(co);
 266         }
 267     }
 268     else
 269     {
 270         non_block_events(co);
 271
 272         ZOOM_connection_fire_event_socket(co->link, event);
 273
 274         non_block_events(co);
 275     }
 276 }
 277
 278
 279 // Disassociate connection from client
 280 void connection_release(struct connection *co)
 281 {
 282     struct client *cl = co->client;
 283
 284     if (!cl)
 285         return;
 286     client_set_connection(cl, 0);
 287     co->client = 0;
 288 }
 289
 290 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
 291 {
 292     struct connection *con;
 293
 294 start:
 295     yaz_mutex_enter(host->mutex);
 296     con = host->connections;
 297     while (con)
 298     {
 299         if (con->state == Conn_Resolving)
 300         {
 301             if (!host->ipport) /* unresolved */
 302             {
 303                 yaz_mutex_leave(host->mutex);
 304                 connection_destroy(con);
 305                 goto start;
 306                 /* start all over .. at some point it will be NULL */
 307             }
 308             else if (!con->client)
 309             {
 310                 yaz_mutex_leave(host->mutex);
 311                 connection_destroy(con);
 312                 /* start all over .. at some point it will be NULL */
 313                 goto start;
 314             }
 315             else
 316             {
 317                 yaz_mutex_leave(host->mutex);
 318                 connection_connect(con, iochan_man);
 319                 client_start_search(con->client);
 320                 goto start;
 321             }
 322         }
 323         else
 324         {
 325             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 326             con = con->next;
 327         }
 328     }
 329     yaz_mutex_leave(host->mutex);
 330 }
 331
 332 static struct host *connection_get_host(struct connection *con)
 333 {
 334     return con->host;
 335 }
 336
 337 // Callback for use by event loop
 338 // We do this because ZOOM connections don't always have (the same) sockets
 339 static int socketfun(IOCHAN c)
 340 {
 341     struct connection *co = iochan_getdata(c);
 342     if (!co->link)
 343         return -1;
 344     return ZOOM_connection_get_socket(co->link);
 345 }
 346
 347 // Because ZOOM always knows what events it is interested in; we may not
 348 static int maskfun(IOCHAN c)
 349 {
 350     struct connection *co = iochan_getdata(c);
 351     if (!co->link)
 352         return 0;
 353
 354     // This is cheating a little, and assuming that eventl mask IDs are always
 355     // the same as ZOOM-C's.
 356     return ZOOM_connection_get_mask(co->link);
 357 }
 358
 359 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 360 {
 361     ZOOM_connection link = 0;
 362     struct host *host = connection_get_host(con);
 363     ZOOM_options zoptions = ZOOM_options_create();
 364     const char *auth;
 365     const char *charset;
 366     const char *sru;
 367     const char *sru_version = 0;
 368
 369     struct session_database *sdb = client_get_database(con->client);
 370     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 371     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
 372
 373     assert(host->ipport);
 374     assert(con);
 375
 376     ZOOM_options_set(zoptions, "async", "1");
 377     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
 378     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
 379
 380     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
 381         ZOOM_options_set(zoptions, "charset", charset);
 382
 383     if (zproxy && *zproxy)
 384     {
 385         con->zproxy = xstrdup(zproxy);
 386         ZOOM_options_set(zoptions, "proxy", zproxy);
 387     }
 388     if (apdulog && *apdulog)
 389         ZOOM_options_set(zoptions, "apdulog", apdulog);
 390
 391     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 392         ZOOM_options_set(zoptions, "user", auth);
 393     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 394         ZOOM_options_set(zoptions, "sru", sru);
 395     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 396         && *sru_version)
 397         ZOOM_options_set(zoptions, "sru_version", sru_version);
 398
 399     if (!(link = ZOOM_connection_create(zoptions)))
 400     {
 401         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 402         ZOOM_options_destroy(zoptions);
 403         return -1;
 404     }
 405
 406     if (sru && *sru)
 407     {
 408         char http_hostport[512];
 409         strcpy(http_hostport, "http://");
 410         strcat(http_hostport, host->hostport);
 411         ZOOM_connection_connect(link, http_hostport, 0);
 412     }
 413     else
 414         ZOOM_connection_connect(link, host->ipport, 0);
 415
 416     con->link = link;
 417     con->iochan = iochan_create(0, connection_handler, 0);
 418     con->state = Conn_Connecting;
 419     iochan_settimeout(con->iochan, con->operation_timeout);
 420     iochan_setdata(con->iochan, con);
 421     iochan_setsocketfun(con->iochan, socketfun);
 422     iochan_setmaskfun(con->iochan, maskfun);
 423     iochan_add(iochan_man, con->iochan);
 424
 425     /* this fragment is bad DRY: from client_prep_connection */
 426     client_set_state(con->client, Client_Connecting);
 427     ZOOM_options_destroy(zoptions);
 428     return 0;
 429 }
 430
 431 const char *connection_get_url(struct connection *co)
 432 {
 433     return client_get_url(co->client);
 434 }
 435
 436 // Ensure that client has a connection associated
 437 int client_prep_connection(struct client *cl,
 438                            int operation_timeout, int session_timeout,
 439                            iochan_man_t iochan_man)
 440 {
 441     struct connection *co;
 442     struct host *host = client_get_host(cl);
 443     struct session_database *sdb = client_get_database(cl);
 444     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 445
 446     if (zproxy && zproxy[0] == '\0')
 447         zproxy = 0;
 448
 449     if (!host)
 450         return 0;
 451
 452     co = client_get_connection(cl);
 453
 454     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 455
 456     if (!co)
 457     {
 458         // See if someone else has an idle connection
 459         // We should look at timestamps here to select the longest-idle connection
 460         yaz_mutex_enter(host->mutex);
 461         for (co = host->connections; co; co = co->next)
 462             if (connection_is_idle(co) &&
 463                 (!co->client || client_get_state(co->client) == Client_Idle) &&
 464                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 465                         session_setting_oneval(client_get_database(cl),
 466                                                PZ_AUTHENTICATION)))
 467             {
 468                 if (zproxy == 0 && co->zproxy == 0)
 469                     break;
 470                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 471                     break;
 472             }
 473         if (co)
 474         {
 475             connection_release(co);
 476             client_set_connection(cl, co);
 477             co->client = cl;
 478             yaz_mutex_leave(host->mutex);
 479             co->operation_timeout = operation_timeout;
 480             co->session_timeout = session_timeout;
 481             /* tells ZOOM to reconnect if necessary. Disabled becuase
 482                the ZOOM_connection_connect flushes the task queue */
 483             ZOOM_connection_connect(co->link, 0, 0);
 484         }
 485         else
 486         {
 487             yaz_mutex_leave(host->mutex);
 488             co = connection_create(cl, operation_timeout, session_timeout,
 489                                    iochan_man);
 490         }
 491     }
 492
 493     if (co && co->link)
 494         return 1;
 495     else
 496         return 0;
 497 }
 498
 499 /*
 500  * Local variables:
 501  * c-basic-offset: 4
 502  * c-file-style: "Stroustrup"
 503  * indent-tabs-mode: nil
 504  * End:
 505  * vim: shiftwidth=4 tabstop=8 expandtab
 506  */
 507