51468c4fb8c7cbce9f24054e5370d91388070665
[pazpar2-moved-to-github.git] / src / connection.c
1 /* This file is part of Pazpar2.
2    Copyright (C) 2006-2013 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 /* connection counting (1) , disable connection counting (0) */
51 #if 1
52 static YAZ_MUTEX g_mutex = 0;
53 static int no_connections = 0;
54 static int total_no_connections = 0;
55
56 static int connection_use(int delta)
57 {
58     int result;
59     if (!g_mutex)
60         yaz_mutex_create(&g_mutex);
61     yaz_mutex_enter(g_mutex);
62     no_connections += delta;
63     result = no_connections;
64     if (delta > 0)
65         total_no_connections += delta;
66     yaz_mutex_leave(g_mutex);
67     if (delta == 0)
68             return result;
69     yaz_log(YLOG_LOG, "%s connections=%d", delta > 0 ? "INC" : "DEC",
70             no_connections);
71     return result;
72 }
73
74 int connections_count(void)
75 {
76     return connection_use(0);
77 }
78
79
80 #else
81 #define connection_use(x)
82 #define connections_count(x) 0
83 #define connections_count_total(x) 0
84 #endif
85
86
87 /** \brief Represents a physical, reusable  connection to a remote Z39.50 host
88  */
89 struct connection {
90     IOCHAN iochan;
91     ZOOM_connection link;
92     struct host *host;
93     struct client *client;
94     char *zproxy;
95     char *url;
96     enum {
97         Conn_Closed,
98         Conn_Connecting,
99         Conn_Open
100     } state;
101     int operation_timeout;
102     int session_timeout;
103     struct connection *next; // next for same host or next in free list
104 };
105
106 static int connection_connect(struct connection *con, iochan_man_t iochan_man);
107
108 static int connection_is_idle(struct connection *co)
109 {
110     ZOOM_connection link = co->link;
111     int event;
112
113     if (co->state != Conn_Open || !link)
114         return 0;
115
116     if (!ZOOM_connection_is_idle(link))
117         return 0;
118     event = ZOOM_connection_peek_event(link);
119     if (event == ZOOM_EVENT_NONE)
120         return 1;
121     else
122         return 0;
123 }
124
125 ZOOM_connection connection_get_link(struct connection *co)
126 {
127     return co->link;
128 }
129
130 static void remove_connection_from_host(struct connection *con)
131 {
132     struct connection **conp = &con->host->connections;
133     assert(con);
134     while (*conp)
135     {
136         if (*conp == con)
137         {
138             *conp = (*conp)->next;
139             break;
140         }
141         conp = &(*conp)->next;
142     }
143     yaz_cond_broadcast(con->host->cond_ready);
144 }
145
146 // Close connection and recycle structure
147 static void connection_destroy(struct connection *co)
148 {
149     if (co->link)
150     {
151         ZOOM_connection_destroy(co->link);
152         iochan_destroy(co->iochan);
153     }
154     yaz_log(YLOG_DEBUG, "%p Connection destroy %s", co, co->url);
155
156     if (co->client)
157     {
158         client_disconnect(co->client);
159     }
160
161     xfree(co->zproxy);
162     xfree(co->url);
163     xfree(co);
164     connection_use(-1);
165 }
166
167 // Creates a new connection for client, associated with the host of
168 // client's database
169 static struct connection *connection_create(struct client *cl,
170                                             const char *url,
171                                             struct host *host,
172                                             int operation_timeout,
173                                             int session_timeout,
174                                             iochan_man_t iochan_man)
175 {
176     struct connection *co;
177
178     co = xmalloc(sizeof(*co));
179     co->host = host;
180
181     co->client = cl;
182     co->url = xstrdup(url);
183     co->zproxy = 0;
184     client_set_connection(cl, co);
185     co->link = 0;
186     co->state = Conn_Closed;
187     co->operation_timeout = operation_timeout;
188     co->session_timeout = session_timeout;
189
190     if (host->ipport)
191         connection_connect(co, iochan_man);
192
193     yaz_mutex_enter(host->mutex);
194     co->next = co->host->connections;
195     co->host->connections = co;
196     yaz_mutex_leave(host->mutex);
197
198     connection_use(1);
199     return co;
200 }
201
202 static void non_block_events(struct connection *co)
203 {
204     int got_records = 0;
205     IOCHAN iochan = co->iochan;
206     ZOOM_connection link = co->link;
207     while (1)
208     {
209         struct client *cl = co->client;
210         int ev;
211         int r = ZOOM_event_nonblock(1, &link);
212         if (!r)
213             break;
214         if (!cl)
215             continue;
216         ev = ZOOM_connection_last_event(link);
217
218 #if 1
219         yaz_log(YLOG_DEBUG, "%p Connection ZOOM_EVENT_%s", co, ZOOM_get_event_str(ev));
220 #endif
221         switch (ev)
222         {
223         case ZOOM_EVENT_TIMEOUT:
224             break;
225         case ZOOM_EVENT_END:
226             {
227                 const char *error, *addinfo;
228                 int err;
229                 if ((err = ZOOM_connection_error(link, &error, &addinfo)))
230                 {
231                     yaz_log(YLOG_LOG, "Error %s from %s",
232                             error, client_get_id(cl));
233                     client_set_diagnostic(cl, err, error, addinfo);
234                     client_set_state(cl, Client_Error);
235                 }
236                 else
237                 {
238                     iochan_settimeout(iochan, co->session_timeout);
239                     client_set_state(cl, Client_Idle);
240                 }
241                 yaz_cond_broadcast(co->host->cond_ready);
242             }
243             break;
244         case ZOOM_EVENT_SEND_DATA:
245             break;
246         case ZOOM_EVENT_RECV_DATA:
247             break;
248         case ZOOM_EVENT_UNKNOWN:
249             break;
250         case ZOOM_EVENT_SEND_APDU:
251             client_set_state(co->client, Client_Working);
252             iochan_settimeout(iochan, co->operation_timeout);
253             break;
254         case ZOOM_EVENT_RECV_APDU:
255             break;
256         case ZOOM_EVENT_CONNECT:
257             yaz_log(YLOG_LOG, "Connected to %s", client_get_id(cl));
258             co->state = Conn_Open;
259             break;
260         case ZOOM_EVENT_RECV_SEARCH:
261             client_search_response(cl);
262             break;
263         case ZOOM_EVENT_RECV_RECORD:
264             client_record_response(cl, &got_records);
265             break;
266         default:
267             yaz_log(YLOG_LOG, "Unhandled event (%d) from %s",
268                     ev, client_get_id(cl));
269             break;
270         }
271     }
272     if (got_records)
273     {
274         struct client *cl = co->client;
275         if (cl)
276         {
277             client_check_preferred_watch(cl);
278             client_got_records(cl);
279         }
280     }
281 }
282
283 void connection_continue(struct connection *co)
284 {
285     int r = ZOOM_connection_exec_task(co->link);
286     if (!r)
287         non_block_events(co);
288     else
289     {
290         iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
291         iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
292     }
293 }
294
295 static void connection_handler(IOCHAN iochan, int event)
296 {
297     struct connection *co = iochan_getdata(iochan);
298     struct client *cl;
299     struct host *host = co->host;
300
301     yaz_mutex_enter(host->mutex);
302     cl = co->client;
303     if (!cl)
304     {
305         /* no client associated with it.. We are probably getting
306            a closed connection from the target.. Or, perhaps, an unexpected
307            package.. We will just close the connection */
308         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
309         remove_connection_from_host(co);
310         yaz_mutex_leave(host->mutex);
311         connection_destroy(co);
312     }
313     else if (event & EVENT_TIMEOUT)
314     {
315         ZOOM_connection_fire_event_timeout(co->link);
316         client_lock(cl);
317         non_block_events(co);
318         client_unlock(cl);
319
320         remove_connection_from_host(co);
321         yaz_mutex_leave(host->mutex);
322         connection_destroy(co);
323     }
324     else
325     {
326         yaz_mutex_leave(host->mutex);
327
328         client_lock(cl);
329         non_block_events(co);
330
331         ZOOM_connection_fire_event_socket(co->link, event);
332
333         non_block_events(co);
334         client_unlock(cl);
335
336         if (co->link)
337         {
338             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
339             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
340         }
341     }
342 }
343
344
345 // Disassociate connection from client
346 static void connection_release(struct connection *co)
347 {
348     struct client *cl = co->client;
349
350     if (!cl)
351         return;
352     client_set_connection(cl, 0);
353     co->client = 0;
354 }
355
356 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
357 {
358     struct connection *con;
359
360     yaz_mutex_enter(host->mutex);
361     con = host->connections;
362     while (con)
363     {
364         if (con->state == Conn_Closed)
365         {
366             if (!host->ipport || !con->client) /* unresolved or no client */
367             {
368                 remove_connection_from_host(con);
369                 yaz_mutex_leave(host->mutex);
370                 connection_destroy(con);
371             }
372             else
373             {
374                 struct session_database *sdb = client_get_database(con->client);
375                 if (sdb)
376                 {
377                     yaz_mutex_leave(host->mutex);
378                     client_start_search(con->client);
379                 }
380                 else
381                 {
382                     remove_connection_from_host(con);
383                     yaz_mutex_leave(host->mutex);
384                     connection_destroy(con);
385                 }
386             }
387             /* start all over .. at some point it will be NULL */
388             yaz_mutex_enter(host->mutex);
389             con = host->connections;
390         }
391         else
392         {
393             yaz_log(YLOG_LOG, "connect_resolver_host: state=%d", con->state);
394             con = con->next;
395         }
396     }
397     yaz_mutex_leave(host->mutex);
398 }
399
400 static struct host *connection_get_host(struct connection *con)
401 {
402     return con->host;
403 }
404
405 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
406 {
407     struct host *host = connection_get_host(con);
408     ZOOM_options zoptions = ZOOM_options_create();
409     const char *auth;
410     const char *charset;
411     const char *sru;
412     const char *sru_version = 0;
413     WRBUF w;
414
415     struct session_database *sdb = client_get_database(con->client);
416     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
417
418     assert(con);
419
420     ZOOM_options_set(zoptions, "async", "1");
421     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
422     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
423
424     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
425         ZOOM_options_set(zoptions, "charset", charset);
426
427     assert(host->ipport);
428     if (host->proxy)
429     {
430         yaz_log(YLOG_LOG, "proxy=%s", host->ipport);
431         ZOOM_options_set(zoptions, "proxy", host->ipport);
432     }
433     else
434     {
435         assert(host->tproxy);
436         yaz_log(YLOG_LOG, "tproxy=%s", host->ipport);
437         ZOOM_options_set(zoptions, "tproxy", host->ipport);
438     }
439
440     if (apdulog && *apdulog)
441         ZOOM_options_set(zoptions, "apdulog", apdulog);
442
443     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
444     {
445         const char *cp1 = strchr(auth, ' ');
446         if (!cp1)
447             ZOOM_options_set(zoptions, "user", auth);
448         else
449         {
450             const char *cp2 = strchr(cp1 + 1, ' ');
451
452             ZOOM_options_setl(zoptions, "user", auth, cp1 - auth);
453             if (!cp2)
454                 ZOOM_options_set(zoptions, "password", cp1 + 1);
455             else
456             {
457                 ZOOM_options_setl(zoptions, "group", cp1 + 1, cp2 - cp1 - 1);
458                 ZOOM_options_set(zoptions, "password", cp2 + 1);
459             }
460         }
461     }
462     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
463         ZOOM_options_set(zoptions, "sru", sru);
464     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
465         && *sru_version)
466         ZOOM_options_set(zoptions, "sru_version", sru_version);
467     if (!(con->link = ZOOM_connection_create(zoptions)))
468     {
469         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
470         ZOOM_options_destroy(zoptions);
471         return -1;
472     }
473
474     w = wrbuf_alloc();
475     if (sru && *sru && !strstr(con->url, "://"))
476         wrbuf_puts(w, "http://");
477     if (strchr(con->url, '#'))
478     {
479         const char *cp = strchr(con->url, '#');
480         wrbuf_write(w, con->url, cp - con->url);
481     }
482     else
483         wrbuf_puts(w, con->url);
484
485     ZOOM_connection_connect(con->link, wrbuf_cstr(w), 0);
486
487     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
488     con->state = Conn_Connecting;
489     iochan_settimeout(con->iochan, con->operation_timeout);
490     iochan_setdata(con->iochan, con);
491     iochan_add(iochan_man, con->iochan);
492
493     client_set_state(con->client, Client_Connecting);
494     ZOOM_options_destroy(zoptions);
495     wrbuf_destroy(w);
496     return 0;
497 }
498
499 // Ensure that client has a connection associated
500 int client_prep_connection(struct client *cl,
501                            int operation_timeout, int session_timeout,
502                            iochan_man_t iochan_man,
503                            const struct timeval *abstime)
504 {
505     struct connection *co;
506     struct session_database *sdb = client_get_database(cl);
507     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
508     const char *url = session_setting_oneval(sdb, PZ_URL);
509     const char *sru = session_setting_oneval(sdb, PZ_SRU);
510     struct host *host = 0;
511     int default_port = *sru ? 80 : 210;
512
513     if (zproxy && zproxy[0] == '\0')
514         zproxy = 0;
515
516     if (!url || !*url)
517         url = sdb->database->id;
518
519     host = find_host(client_get_session(cl)->service->server->database_hosts,
520                      url, zproxy, default_port, iochan_man);
521
522     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
523             client_get_id(cl), url);
524     if (!host)
525         return 0;
526
527     co = client_get_connection(cl);
528     if (co)
529     {
530         assert(co->host);
531         if (co->host == host && client_get_state(cl) == Client_Idle)
532         {
533             return 2;
534         }
535         connection_release(co);
536         co = 0;
537     }
538     if (!co)
539     {
540         int max_connections = 0;
541         int reuse_connections = 1;
542         const char *v = session_setting_oneval(client_get_database(cl),
543                                                PZ_MAX_CONNECTIONS);
544         if (v && *v)
545             max_connections = atoi(v);
546
547         v = session_setting_oneval(client_get_database(cl),
548                 PZ_REUSE_CONNECTIONS);
549         if (v && *v)
550             reuse_connections = atoi(v);
551
552         // See if someone else has an idle connection
553         // We should look at timestamps here to select the longest-idle connection
554         yaz_mutex_enter(host->mutex);
555         while (1)
556         {
557             int num_connections = 0;
558             for (co = host->connections; co; co = co->next)
559                 num_connections++;
560             if (reuse_connections)
561             {
562                 for (co = host->connections; co; co = co->next)
563                 {
564                     if (connection_is_idle(co) &&
565                         !strcmp(url, co->url) &&
566                         (!co->client || client_get_state(co->client) == Client_Idle) &&
567                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
568                                 session_setting_oneval(client_get_database(cl),
569                                                        PZ_AUTHENTICATION)))
570                     {
571                         if (zproxy == 0 && co->zproxy == 0)
572                             break;
573                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
574                             break;
575                     }
576                 }
577                 if (co)
578                 {
579                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
580                     break;
581                 }
582             }
583             if (max_connections <= 0 || num_connections < max_connections)
584             {
585                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
586                         num_connections, max_connections);
587                 break;
588             }
589             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
590                     num_connections, max_connections);
591             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
592             {
593                 yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
594                 client_set_state(cl, Client_Error);
595                 yaz_mutex_leave(host->mutex);
596                 return 0;
597             }
598         }
599         if (co)
600         {
601             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
602             connection_release(co);
603             client_set_connection(cl, co);
604             co->client = cl;
605             /* ensure that connection is only assigned to this client
606                by marking the client non Idle */
607             client_set_state(cl, Client_Working);
608             yaz_mutex_leave(host->mutex);
609             co->operation_timeout = operation_timeout;
610             co->session_timeout = session_timeout;
611             /* tells ZOOM to reconnect if necessary. Disabled becuase
612                the ZOOM_connection_connect flushes the task queue */
613             ZOOM_connection_connect(co->link, 0, 0);
614         }
615         else
616         {
617             yaz_mutex_leave(host->mutex);
618             co = connection_create(cl, url, host,
619                                    operation_timeout, session_timeout,
620                                    iochan_man);
621         }
622         assert(co->host);
623     }
624
625     if (co && co->link)
626         return 1;
627     else
628         return 0;
629 }
630
631 /*
632  * Local variables:
633  * c-basic-offset: 4
634  * c-file-style: "Stroustrup"
635  * indent-tabs-mode: nil
636  * End:
637  * vim: shiftwidth=4 tabstop=8 expandtab
638  */
639