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 "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 connect_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;
  72
  73 static int connection_connect(struct connection *con);
  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 connect_timeout,
 138                                             int session_timeout)
 139 {
 140     struct connection *new;
 141     struct host *host = client_get_host(cl);
 142
 143     if ((new = connection_freelist))
 144         connection_freelist = new->next;
 145     else
 146     {
 147         new = xmalloc(sizeof (struct connection));
 148         new->ibuf = 0;
 149         new->ibufsize = 0;
 150     }
 151     new->host = host;
 152     new->next = new->host->connections;
 153     new->host->connections = new;
 154     new->client = cl;
 155     new->zproxy = 0;
 156     client_set_connection(cl, new);
 157     new->link = 0;
 158     new->state = Conn_Resolving;
 159     new->connect_timeout = connect_timeout;
 160     new->session_timeout = session_timeout;
 161     if (host->ipport)
 162         connection_connect(new);
 163     return new;
 164 }
 165
 166 static void non_block_events(struct connection *co)
 167 {
 168     struct client *cl = co->client;
 169     IOCHAN iochan = co->iochan;
 170     ZOOM_connection link = co->link;
 171     while (1)
 172     {
 173         int ev;
 174         int r = ZOOM_event_nonblock(1, &link);
 175         if (!r)
 176             break;
 177         ev = ZOOM_connection_last_event(link);
 178 #if 0
 179         yaz_log(YLOG_LOG, "ZOOM_EVENT_%s", ZOOM_get_event_str(ev));
 180 #endif
 181         switch (ev)
 182         {
 183         case ZOOM_EVENT_END:
 184             {
 185                 const char *error, *addinfo;
 186                 if (ZOOM_connection_error(link, &error, &addinfo))
 187                 {
 188                     yaz_log(YLOG_LOG, "Error %s from %s",
 189                             error, client_get_url(cl));
 190                 }
 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             break;
 203         case ZOOM_EVENT_RECV_APDU:
 204             break;
 205         case ZOOM_EVENT_CONNECT:
 206             yaz_log(YLOG_LOG, "Connected to %s", client_get_url(cl));
 207             co->state = Conn_Open;
 208             iochan_settimeout(iochan, co->session_timeout);
 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)
 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);
 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)
 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 *sru;
 347     const char *sru_version = 0;
 348     char ipport[512] = "";
 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     if (zproxy && *zproxy)
 361     {
 362         con->zproxy = xstrdup(zproxy);
 363         ZOOM_options_set(zoptions, "proxy", zproxy);
 364     }
 365     if (apdulog && *apdulog)
 366         ZOOM_options_set(zoptions, "apdulog", apdulog);
 367
 368     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
 369         ZOOM_options_set(zoptions, "user", auth);
 370     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
 371         ZOOM_options_set(zoptions, "sru", sru);
 372     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
 373         && *sru_version)
 374         ZOOM_options_set(zoptions, "sru_version", sru_version);
 375
 376     if (!(link = ZOOM_connection_create(zoptions)))
 377     {
 378         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
 379         ZOOM_options_destroy(zoptions);
 380         return -1;
 381     }
 382
 383     if (sru && *sru)
 384         strcpy(ipport, "http://");
 385     strcat(ipport, host->ipport);
 386
 387     ZOOM_connection_connect(link, ipport, 0);
 388
 389     con->link = link;
 390     con->iochan = iochan_create(0, connection_handler, 0);
 391     con->state = Conn_Connecting;
 392     iochan_settimeout(con->iochan, con->connect_timeout);
 393     iochan_setdata(con->iochan, con);
 394     iochan_setsocketfun(con->iochan, socketfun);
 395     iochan_setmaskfun(con->iochan, maskfun);
 396     pazpar2_add_channel(con->iochan);
 397
 398     /* this fragment is bad DRY: from client_prep_connection */
 399     client_set_state(con->client, Client_Connecting);
 400     ZOOM_options_destroy(zoptions);
 401     return 0;
 402 }
 403
 404 const char *connection_get_url(struct connection *co)
 405 {
 406     return client_get_url(co->client);
 407 }
 408
 409 // Ensure that client has a connection associated
 410 int client_prep_connection(struct client *cl,
 411                            int connect_timeout, int session_timeout)
 412 {
 413     struct connection *co;
 414     struct session *se = client_get_session(cl);
 415     struct host *host = client_get_host(cl);
 416     struct session_database *sdb = client_get_database(cl);
 417     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
 418
 419     if (zproxy && zproxy[0] == '\0')
 420         zproxy = 0;
 421
 422     if (!host)
 423         return 0;
 424
 425     co = client_get_connection(cl);
 426
 427     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 428
 429     if (!co)
 430     {
 431         // See if someone else has an idle connection
 432         // We should look at timestamps here to select the longest-idle connection
 433         for (co = host->connections; co; co = co->next)
 434             if (connection_is_idle(co) &&
 435                 (!co->client || client_get_session(co->client) != se) &&
 436                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 437                         session_setting_oneval(client_get_database(cl),
 438                                                PZ_AUTHENTICATION)))
 439             {
 440                 if (zproxy == 0 && co->zproxy == 0)
 441                     break;
 442                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 443                     break;
 444             }
 445         if (co)
 446         {
 447             connection_release(co);
 448             client_set_connection(cl, co);
 449             co->client = cl;
 450             /* tells ZOOM to reconnect if necessary. Disabled becuase
 451                the ZOOM_connection_connect flushes the task queue */
 452             co->connect_timeout = connect_timeout;
 453             co->session_timeout = session_timeout;
 454             ZOOM_connection_connect(co->link, 0, 0);
 455         }
 456         else
 457         {
 458             co = connection_create(cl, connect_timeout, session_timeout);
 459         }
 460     }
 461
 462     if (co && co->link)
 463         return 1;
 464     else
 465         return 0;
 466 }
 467
 468 /*
 469  * Local variables:
 470  * c-basic-offset: 4
 471  * c-file-style: "Stroustrup"
 472  * indent-tabs-mode: nil
 473  * End:
 474  * vim: shiftwidth=4 tabstop=8 expandtab
 475  */
 476