41e693c52403406ada3dee92c9a4fd05c4aca833
[pazpar2-moved-to-github.git] / src / connection.c
1 /* This file is part of Pazpar2.
2    Copyright (C) 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     {
288         struct client *cl = co->client;
289
290         client_lock(cl);
291         non_block_events(co);
292         client_unlock(cl);
293     }
294     else
295     {
296         iochan_setflags(co->iochan, ZOOM_connection_get_mask(co->link));
297         iochan_setfd(co->iochan, ZOOM_connection_get_socket(co->link));
298     }
299 }
300
301 static void connection_handler(IOCHAN iochan, int event)
302 {
303     struct connection *co = iochan_getdata(iochan);
304     struct client *cl;
305     struct host *host = co->host;
306
307     yaz_mutex_enter(host->mutex);
308     cl = co->client;
309     if (!cl)
310     {
311         /* no client associated with it.. We are probably getting
312            a closed connection from the target.. Or, perhaps, an unexpected
313            package.. We will just close the connection */
314         yaz_log(YLOG_LOG, "timeout connection %p event=%d", co, event);
315         remove_connection_from_host(co);
316         yaz_mutex_leave(host->mutex);
317         connection_destroy(co);
318     }
319     else if (event & EVENT_TIMEOUT)
320     {
321         ZOOM_connection_fire_event_timeout(co->link);
322         client_lock(cl);
323         non_block_events(co);
324         client_unlock(cl);
325
326         remove_connection_from_host(co);
327         yaz_mutex_leave(host->mutex);
328         connection_destroy(co);
329     }
330     else
331     {
332         yaz_mutex_leave(host->mutex);
333
334         client_lock(cl);
335         non_block_events(co);
336
337         ZOOM_connection_fire_event_socket(co->link, event);
338
339         non_block_events(co);
340         client_unlock(cl);
341
342         if (co->link)
343         {
344             iochan_setflags(iochan, ZOOM_connection_get_mask(co->link));
345             iochan_setfd(iochan, ZOOM_connection_get_socket(co->link));
346         }
347     }
348 }
349
350
351 // Disassociate connection from client
352 static void connection_release(struct connection *co)
353 {
354     struct client *cl = co->client;
355
356     if (!cl)
357         return;
358     client_set_connection(cl, 0);
359     co->client = 0;
360 }
361
362 void connect_resolver_host(struct host *host, iochan_man_t iochan_man)
363 {
364     struct connection *con;
365
366     yaz_mutex_enter(host->mutex);
367     con = host->connections;
368     while (con)
369     {
370         if (con->state == Conn_Closed)
371         {
372             if (!host->ipport || !con->client) /* unresolved or no client */
373             {
374                 remove_connection_from_host(con);
375                 yaz_mutex_leave(host->mutex);
376                 connection_destroy(con);
377             }
378             else
379             {
380                 struct session_database *sdb = client_get_database(con->client);
381                 if (sdb)
382                 {
383                     yaz_mutex_leave(host->mutex);
384                     client_start_search(con->client);
385                 }
386                 else
387                 {
388                     remove_connection_from_host(con);
389                     yaz_mutex_leave(host->mutex);
390                     connection_destroy(con);
391                 }
392             }
393             /* start all over .. at some point it will be NULL */
394             yaz_mutex_enter(host->mutex);
395             con = host->connections;
396         }
397         else
398         {
399             con = con->next;
400         }
401     }
402     yaz_mutex_leave(host->mutex);
403 }
404
405 static struct host *connection_get_host(struct connection *con)
406 {
407     return con->host;
408 }
409
410 static int connection_connect(struct connection *con, iochan_man_t iochan_man)
411 {
412     struct host *host = connection_get_host(con);
413     ZOOM_options zoptions = ZOOM_options_create();
414     const char *auth;
415     const char *charset;
416     const char *sru;
417     const char *sru_version = 0;
418     const char *value;
419     WRBUF w;
420
421     struct session_database *sdb = client_get_database(con->client);
422     const char *apdulog = session_setting_oneval(sdb, PZ_APDULOG);
423     const char *memcached = session_setting_oneval(sdb, PZ_MEMCACHED);
424
425     assert(con);
426
427     ZOOM_options_set(zoptions, "async", "1");
428     ZOOM_options_set(zoptions, "implementationName", PACKAGE_NAME);
429     ZOOM_options_set(zoptions, "implementationVersion", VERSION);
430
431     if ((charset = session_setting_oneval(sdb, PZ_NEGOTIATION_CHARSET)))
432         ZOOM_options_set(zoptions, "charset", charset);
433     if (memcached && *memcached)
434         ZOOM_options_set(zoptions, "memcached", memcached);
435
436     assert(host->ipport);
437     if (host->proxy)
438     {
439         yaz_log(YLOG_LOG, "proxy=%s", host->ipport);
440         ZOOM_options_set(zoptions, "proxy", host->ipport);
441     }
442     else
443     {
444         assert(host->tproxy);
445         yaz_log(YLOG_LOG, "tproxy=%s", host->ipport);
446         ZOOM_options_set(zoptions, "tproxy", host->ipport);
447     }
448
449     if (apdulog && *apdulog)
450         ZOOM_options_set(zoptions, "apdulog", apdulog);
451
452
453     if ((sru = session_setting_oneval(sdb, PZ_SRU)) && *sru)
454         ZOOM_options_set(zoptions, "sru", sru);
455     if ((sru_version = session_setting_oneval(sdb, PZ_SRU_VERSION))
456         && *sru_version)
457         ZOOM_options_set(zoptions, "sru_version", sru_version);
458
459     if ((auth = session_setting_oneval(sdb, PZ_AUTHENTICATION)))
460     {
461         /* allow splitting user and reset with a blank always */
462         const char *cp1 = strchr(auth, ' ');
463         if (!cp1 && sru && *sru)
464             cp1 =  strchr(auth, '/');
465         if (!cp1)
466         {
467             /* Z39.50 user/password style, or no password for SRU */
468             ZOOM_options_set(zoptions, "user", auth);
469         }
470         else
471         {
472             /* now consider group as well */
473             const char *cp2 = strchr(cp1 + 1, ' ');
474
475             ZOOM_options_setl(zoptions, "user", auth, cp1 - auth);
476             if (!cp2)
477                 ZOOM_options_set(zoptions, "password", cp1 + 1);
478             else
479             {
480                 ZOOM_options_setl(zoptions, "group", cp1 + 1, cp2 - cp1 - 1);
481                 ZOOM_options_set(zoptions, "password", cp2 + 1);
482             }
483         }
484     }
485
486     value = session_setting_oneval(sdb, PZ_AUTHENTICATION_MODE);
487     if (value && *value)
488         ZOOM_options_set(zoptions, "authenticationMode", value);
489
490     if (!(con->link = ZOOM_connection_create(zoptions)))
491     {
492         yaz_log(YLOG_FATAL|YLOG_ERRNO, "Failed to create ZOOM Connection");
493         ZOOM_options_destroy(zoptions);
494         return -1;
495     }
496
497     w = wrbuf_alloc();
498     if (sru && *sru && !strstr(con->url, "://"))
499         wrbuf_puts(w, "http://");
500     if (strchr(con->url, '#'))
501     {
502         const char *cp = strchr(con->url, '#');
503         wrbuf_write(w, con->url, cp - con->url);
504     }
505     else
506         wrbuf_puts(w, con->url);
507
508     ZOOM_connection_connect(con->link, wrbuf_cstr(w), 0);
509
510     con->iochan = iochan_create(-1, connection_handler, 0, "connection_socket");
511     con->state = Conn_Connecting;
512     iochan_settimeout(con->iochan, con->operation_timeout);
513     iochan_setdata(con->iochan, con);
514     iochan_add(iochan_man, con->iochan);
515
516     client_set_state(con->client, Client_Connecting);
517     ZOOM_options_destroy(zoptions);
518     wrbuf_destroy(w);
519     return 0;
520 }
521
522 // Ensure that client has a connection associated
523 int client_prep_connection(struct client *cl,
524                            int operation_timeout, int session_timeout,
525                            iochan_man_t iochan_man,
526                            const struct timeval *abstime)
527 {
528     struct connection *co;
529     struct session_database *sdb = client_get_database(cl);
530     const char *zproxy = session_setting_oneval(sdb, PZ_ZPROXY);
531     const char *url = session_setting_oneval(sdb, PZ_URL);
532     const char *sru = session_setting_oneval(sdb, PZ_SRU);
533     struct host *host = 0;
534     int default_port = *sru ? 80 : 210;
535
536     if (zproxy && zproxy[0] == '\0')
537         zproxy = 0;
538
539     if (!url || !*url)
540         url = sdb->database->id;
541
542     host = find_host(client_get_session(cl)->service->server->database_hosts,
543                      url, zproxy, default_port, iochan_man);
544
545     yaz_log(YLOG_DEBUG, "client_prep_connection: target=%s url=%s",
546             client_get_id(cl), url);
547     if (!host)
548         return 0;
549
550     co = client_get_connection(cl);
551     if (co)
552     {
553         assert(co->host);
554         if (co->host == host && client_get_state(cl) == Client_Idle)
555         {
556             return 2;
557         }
558         connection_release(co);
559         co = 0;
560     }
561     if (!co)
562     {
563         int max_connections = 0;
564         int reuse_connections = 1;
565         const char *v = session_setting_oneval(client_get_database(cl),
566                                                PZ_MAX_CONNECTIONS);
567         if (v && *v)
568             max_connections = atoi(v);
569
570         v = session_setting_oneval(client_get_database(cl),
571                 PZ_REUSE_CONNECTIONS);
572         if (v && *v)
573             reuse_connections = atoi(v);
574
575         // See if someone else has an idle connection
576         // We should look at timestamps here to select the longest-idle connection
577         yaz_mutex_enter(host->mutex);
578         while (1)
579         {
580             int num_connections = 0;
581             for (co = host->connections; co; co = co->next)
582                 num_connections++;
583             if (reuse_connections)
584             {
585                 for (co = host->connections; co; co = co->next)
586                 {
587                     if (connection_is_idle(co) &&
588                         !strcmp(url, co->url) &&
589                         (!co->client || client_get_state(co->client) == Client_Idle) &&
590                         !strcmp(ZOOM_connection_option_get(co->link, "user"),
591                                 session_setting_oneval(client_get_database(cl),
592                                                        PZ_AUTHENTICATION)))
593                     {
594                         if (zproxy == 0 && co->zproxy == 0)
595                             break;
596                         if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
597                             break;
598                     }
599                 }
600                 if (co)
601                 {
602                     yaz_log(YLOG_LOG, "num_connections = %d (reusing)", num_connections);
603                     break;
604                 }
605             }
606             if (max_connections <= 0 || num_connections < max_connections)
607             {
608                 yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
609                         num_connections, max_connections);
610                 break;
611             }
612             yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
613                     num_connections, max_connections);
614             if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
615             {
616                 yaz_log(YLOG_LOG, "out of connections %s", client_get_id(cl));
617                 client_set_state(cl, Client_Error);
618                 yaz_mutex_leave(host->mutex);
619                 return 0;
620             }
621         }
622         if (co)
623         {
624             yaz_log(YLOG_LOG,  "%p Connection reuse. state: %d", co, co->state);
625             connection_release(co);
626             client_set_connection(cl, co);
627             co->client = cl;
628             /* ensure that connection is only assigned to this client
629                by marking the client non Idle */
630             client_set_state(cl, Client_Working);
631             yaz_mutex_leave(host->mutex);
632             co->operation_timeout = operation_timeout;
633             co->session_timeout = session_timeout;
634             /* tells ZOOM to reconnect if necessary. Disabled becuase
635                the ZOOM_connection_connect flushes the task queue */
636             ZOOM_connection_connect(co->link, 0, 0);
637         }
638         else
639         {
640             yaz_mutex_leave(host->mutex);
641             co = connection_create(cl, url, host,
642                                    operation_timeout, session_timeout,
643                                    iochan_man);
644         }
645         assert(co->host);
646     }
647
648     if (co && co->link)
649         return 1;
650     else
651         return 0;
652 }
653
654 /*
655  * Local variables:
656  * c-basic-offset: 4
657  * c-file-style: "Stroustrup"
658  * indent-tabs-mode: nil
659  * End:
660  * vim: shiftwidth=4 tabstop=8 expandtab
661  */
662