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 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;
  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 operation_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->operation_timeout = operation_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                 iochan_settimeout(iochan, co->session_timeout);
 192                 client_set_state(cl, Client_Idle);
 193             }
 194             break;
 195         case ZOOM_EVENT_SEND_DATA:
 196             break;
 197         case ZOOM_EVENT_RECV_DATA:
 198             break;
 199         case ZOOM_EVENT_UNKNOWN:
 200             break;
 201         case ZOOM_EVENT_SEND_APDU:
 202             client_set_state(co->client, Client_Working);
 203             iochan_settimeout(iochan, co->operation_timeout);
 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             break;
 211         case ZOOM_EVENT_RECV_SEARCH:
 212             client_search_response(cl);
 213             break;
 214         case ZOOM_EVENT_RECV_RECORD:
 215             client_record_response(cl);
 216             break;
 217         default:
 218             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
 219                     ev, client_get_url(cl));
 220         }
 221     }
 222 }
 223
 224 void connection_continue(struct connection *co)
 225 {
 226     non_block_events(co);
 227 }
 228
 229 static void connection_handler(IOCHAN iochan, int event)
 230 {
 231     struct connection *co = iochan_getdata(iochan);
 232     struct client *cl = co->client;
 233     struct session *se = 0;
 234
 235     if (cl)
 236         se = client_get_session(cl);
 237     else
 238     {
 239         connection_destroy(co);
 240         return;
 241     }
 242
 243     if (event & EVENT_TIMEOUT)
 244     {
 245         if (co->state == Conn_Connecting)
 246         {
 247             yaz_log(YLOG_WARN,  "connect timeout %s", client_get_url(cl));
 248             client_fatal(cl);
 249         }
 250         else
 251         {
 252             yaz_log(YLOG_LOG,  "idle timeout %s", client_get_url(cl));
 253             connection_destroy(co);
 254         }
 255     }
 256     else
 257     {
 258         non_block_events(co);
 259
 260         ZOOM_connection_fire_event_socket(co->link, event);
 261
 262         non_block_events(co);
 263     }
 264 }
 265
 266
 267 // Disassociate connection from client
 268 void connection_release(struct connection *co)
 269 {
 270     struct client *cl = co->client;
 271
 272     yaz_log(YLOG_DEBUG, "Connection release %s", co->host->hostport);
 273     if (!cl)
 274         return;
 275     client_set_connection(cl, 0);
 276     co->client = 0;
 277 }
 278
 279 void connect_resolver_host(struct host *host)
 280 {
 281     struct connection *con = host->connections;
 282     while (con)
 283     {
 284         if (con->state == Conn_Resolving)
 285         {
 286             if (!host->ipport) /* unresolved */
 287             {
 288                 connection_destroy(con);
 289                 /* start all over .. at some point it will be NULL */
 290                 con = host->connections;
 291                 continue;
 292             }
 293             else if (!con->client)
 294             {
 295                 connection_destroy(con);
 296                 /* start all over .. at some point it will be NULL */
 297                 con = host->connections;
 298                 continue;
 299             }
 300             else
 301             {
 302                 connection_connect(con);
 303                 client_start_search(con->client);
 304             }
 305         }
 306         else
 307         {
 308             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
 309         }
 310         con = con->next;
 311     }
 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)
 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 *sru;
 348     const char *sru_version = 0;
 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     {
 385         char http_hostport[512];
 386         strcpy(http_hostport, "http://");
 387         strcat(http_hostport, host->hostport);
 388         ZOOM_connection_connect(link, http_hostport, 0);
 389     }
 390     else
 391         ZOOM_connection_connect(link, host->ipport, 0);
 392
 393     con->link = link;
 394     con->iochan = iochan_create(0, connection_handler, 0);
 395     con->state = Conn_Connecting;
 396     iochan_settimeout(con->iochan, con->operation_timeout);
 397     iochan_setdata(con->iochan, con);
 398     iochan_setsocketfun(con->iochan, socketfun);
 399     iochan_setmaskfun(con->iochan, maskfun);
 400     pazpar2_add_channel(con->iochan);
 401
 402     /* this fragment is bad DRY: from client_prep_connection */
 403     client_set_state(con->client, Client_Connecting);
 404     ZOOM_options_destroy(zoptions);
 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 operation_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     if (!host)
 427         return 0;
 428
 429     co = client_get_connection(cl);
 430
 431     yaz_log(YLOG_DEBUG, "Client prep %s", client_get_url(cl));
 432
 433     if (!co)
 434     {
 435         // See if someone else has an idle connection
 436         // We should look at timestamps here to select the longest-idle connection
 437         for (co = host->connections; co; co = co->next)
 438             if (connection_is_idle(co) &&
 439                 (!co->client || client_get_session(co->client) != se) &&
 440                 !strcmp(ZOOM_connection_option_get(co->link, "user"),
 441                         session_setting_oneval(client_get_database(cl),
 442                                                PZ_AUTHENTICATION)))
 443             {
 444                 if (zproxy == 0 && co->zproxy == 0)
 445                     break;
 446                 if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
 447                     break;
 448             }
 449         if (co)
 450         {
 451             connection_release(co);
 452             client_set_connection(cl, co);
 453             co->client = cl;
 454             co->operation_timeout = operation_timeout;
 455             co->session_timeout = session_timeout;
 456             /* tells ZOOM to reconnect if necessary. Disabled becuase
 457                the ZOOM_connection_connect flushes the task queue */
 458             ZOOM_connection_connect(co->link, 0, 0);
 459         }
 460         else
 461         {
 462             co = connection_create(cl, operation_timeout, session_timeout);
 463         }
 464     }
 465
 466     if (co && co->link)
 467         return 1;
 468     else
 469         return 0;
 470 }
 471
 472 /*
 473  * Local variables:
 474  * c-basic-offset: 4
 475  * c-file-style: "Stroustrup"
 476  * indent-tabs-mode: nil
 477  * End:
 478  * vim: shiftwidth=4 tabstop=8 expandtab
 479  */
 480