1 /*
2 * SysDB - src/frontend/sock.c
3 * Copyright (C) 2013 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #if HAVE_CONFIG_H
29 # include "config.h"
30 #endif /* HAVE_CONFIG_H */
32 #include "sysdb.h"
33 #include "core/object.h"
34 #include "frontend/connection-private.h"
35 #include "frontend/sock.h"
37 #include "utils/channel.h"
38 #include "utils/error.h"
39 #include "utils/llist.h"
40 #include "utils/os.h"
41 #include "utils/strbuf.h"
43 #include <assert.h>
44 #include <errno.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
50 #include <unistd.h>
52 #include <sys/time.h>
53 #include <sys/types.h>
54 #include <sys/select.h>
55 #include <sys/socket.h>
56 #include <sys/un.h>
58 #include <libgen.h>
60 #include <pthread.h>
62 /*
63 * private data types
64 */
66 typedef struct {
67 char *address;
68 int type;
70 int sock_fd;
71 int (*accept)(sdb_conn_t *);
72 } listener_t;
74 typedef struct {
75 int type;
76 const char *prefix;
78 int (*open)(listener_t *);
79 void (*close)(listener_t *);
80 } fe_listener_impl_t;
82 struct sdb_fe_socket {
83 listener_t *listeners;
84 size_t listeners_num;
86 sdb_llist_t *open_connections;
88 /* channel used for communication between main
89 * and connection handler threads */
90 sdb_channel_t *chan;
91 };
93 /*
94 * connection management functions
95 */
97 static int
98 open_unixsock(listener_t *listener)
99 {
100 char *addr_copy;
101 char *base_dir;
102 struct sockaddr_un sa;
103 int status;
105 listener->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
106 if (listener->sock_fd < 0) {
107 char buf[1024];
108 sdb_log(SDB_LOG_ERR, "frontend: Failed to open UNIX socket %s: %s",
109 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
110 return -1;
111 }
113 memset(&sa, 0, sizeof(sa));
114 sa.sun_family = AF_UNIX;
115 strncpy(sa.sun_path, listener->address, sizeof(sa.sun_path));
117 addr_copy = strdup(listener->address);
118 if (! addr_copy) {
119 char errbuf[1024];
120 sdb_log(SDB_LOG_ERR, "frontend: strdup failed: %s",
121 sdb_strerror(errno, errbuf, sizeof(errbuf)));
122 return -1;
123 }
124 base_dir = dirname(addr_copy);
126 /* ensure that the directory exists */
127 if (sdb_mkdir_all(base_dir, 0777)) {
128 char errbuf[1024];
129 sdb_log(SDB_LOG_ERR, "frontend: Failed to create directory '%s': %s",
130 base_dir, sdb_strerror(errno, errbuf, sizeof(errbuf)));
131 free(addr_copy);
132 return -1;
133 }
134 free(addr_copy);
136 if (unlink(listener->address) && (errno != ENOENT)) {
137 char errbuf[1024];
138 sdb_log(SDB_LOG_WARNING, "frontend: Failed to remove stale UNIX "
139 "socket %s: %s", listener->address,
140 sdb_strerror(errno, errbuf, sizeof(errbuf)));
141 }
143 status = bind(listener->sock_fd, (struct sockaddr *)&sa, sizeof(sa));
144 if (status) {
145 char buf[1024];
146 sdb_log(SDB_LOG_ERR, "frontend: Failed to bind to UNIX socket %s: %s",
147 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
148 return -1;
149 }
150 return 0;
151 } /* open_unixsock */
153 static void
154 close_unixsock(listener_t *listener)
155 {
156 assert(listener);
158 if (! listener->address)
159 return;
161 if (listener->sock_fd >= 0)
162 close(listener->sock_fd);
163 listener->sock_fd = -1;
165 unlink(listener->address);
166 } /* close_unixsock */
168 /*
169 * private variables
170 */
172 /* the enum has to be sorted the same as the implementations array
173 * to ensure that the type may be used as index into the array */
174 enum {
175 LISTENER_UNIXSOCK = 0, /* this is the default */
176 };
177 static fe_listener_impl_t listener_impls[] = {
178 { LISTENER_UNIXSOCK, "unix", open_unixsock, close_unixsock },
179 };
181 /*
182 * private helper functions
183 */
185 static int
186 listener_listen(listener_t *listener)
187 {
188 assert(listener);
190 /* try to reopen */
191 if (listener->sock_fd < 0)
192 if (listener_impls[listener->type].open(listener))
193 return -1;
194 assert(listener->sock_fd >= 0);
196 if (listen(listener->sock_fd, /* backlog = */ 32)) {
197 char buf[1024];
198 sdb_log(SDB_LOG_ERR, "frontend: Failed to listen on socket %s: %s",
199 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
200 return -1;
201 }
202 return 0;
203 } /* listener_listen */
205 static void
206 listener_close(listener_t *listener)
207 {
208 assert(listener);
210 if (listener_impls[listener->type].close)
211 listener_impls[listener->type].close(listener);
213 if (listener->sock_fd >= 0)
214 close(listener->sock_fd);
215 listener->sock_fd = -1;
216 } /* listener_close */
218 static int
219 get_type(const char *address)
220 {
221 char *sep;
222 size_t len;
223 size_t i;
225 sep = strchr(address, (int)':');
226 if (! sep)
227 return listener_impls[0].type;
229 assert(sep > address);
230 len = (size_t)(sep - address);
232 for (i = 0; i < SDB_STATIC_ARRAY_LEN(listener_impls); ++i) {
233 fe_listener_impl_t *impl = listener_impls + i;
235 if (!strncmp(address, impl->prefix, len)) {
236 assert(impl->type == (int)i);
237 return impl->type;
238 }
239 }
240 return -1;
241 } /* get_type */
243 static void
244 listener_destroy(listener_t *listener)
245 {
246 if (! listener)
247 return;
249 listener_close(listener);
251 if (listener->address)
252 free(listener->address);
253 listener->address = NULL;
254 } /* listener_destroy */
256 static listener_t *
257 listener_create(sdb_fe_socket_t *sock, const char *address)
258 {
259 listener_t *listener;
260 size_t len;
261 int type;
263 type = get_type(address);
264 if (type < 0) {
265 sdb_log(SDB_LOG_ERR, "frontend: Unsupported address type specified "
266 "in listen address '%s'", address);
267 return NULL;
268 }
270 listener = realloc(sock->listeners,
271 (sock->listeners_num + 1) * sizeof(*sock->listeners));
272 if (! listener) {
273 char buf[1024];
274 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
275 sdb_strerror(errno, buf, sizeof(buf)));
276 return NULL;
277 }
279 sock->listeners = listener;
280 listener = sock->listeners + sock->listeners_num;
282 len = strlen(listener_impls[type].prefix);
283 if ((! strncmp(address, listener_impls[type].prefix, len))
284 && (address[len] == ':'))
285 address += strlen(listener_impls[type].prefix) + 1;
287 listener->sock_fd = -1;
288 listener->address = strdup(address);
289 if (! listener->address) {
290 char buf[1024];
291 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
292 sdb_strerror(errno, buf, sizeof(buf)));
293 listener_destroy(listener);
294 return NULL;
295 }
296 listener->type = type;
297 listener->accept = NULL;
299 if (listener_impls[type].open(listener)) {
300 /* prints error */
301 listener_destroy(listener);
302 return NULL;
303 }
305 ++sock->listeners_num;
306 return listener;
307 } /* listener_create */
309 static void
310 socket_clear(sdb_fe_socket_t *sock)
311 {
312 size_t i;
314 assert(sock);
315 for (i = 0; i < sock->listeners_num; ++i)
316 listener_destroy(sock->listeners + i);
317 if (sock->listeners)
318 free(sock->listeners);
319 sock->listeners = NULL;
320 sock->listeners_num = 0;
321 } /* socket_clear */
323 static void
324 socket_close(sdb_fe_socket_t *sock)
325 {
326 size_t i;
328 assert(sock);
329 for (i = 0; i < sock->listeners_num; ++i)
330 listener_close(sock->listeners + i);
331 } /* socket_close */
333 /*
334 * connection handler functions
335 */
337 static void *
338 connection_handler(void *data)
339 {
340 sdb_fe_socket_t *sock = data;
342 assert(sock);
344 while (42) {
345 struct timespec timeout = { 0, 500000000 }; /* .5 seconds */
346 sdb_conn_t *conn;
347 int status;
349 errno = 0;
350 status = sdb_channel_select(sock->chan, /* read */ NULL, &conn,
351 /* write */ NULL, NULL, &timeout);
352 if (status) {
353 char buf[1024];
355 if (errno == ETIMEDOUT)
356 continue;
357 if (errno == EBADF) /* channel shut down */
358 break;
360 sdb_log(SDB_LOG_ERR, "frontend: Failed to read from channel: %s",
361 sdb_strerror(errno, buf, sizeof(buf)));
362 continue;
363 }
365 status = (int)sdb_connection_handle(conn);
366 if (status <= 0) {
367 /* error or EOF -> close connection */
368 sdb_object_deref(SDB_OBJ(conn));
369 continue;
370 }
372 /* return the connection to the main loop */
373 if (sdb_llist_append(sock->open_connections, SDB_OBJ(conn))) {
374 sdb_log(SDB_LOG_ERR, "frontend: Failed to re-append "
375 "connection %s to list of open connections",
376 SDB_OBJ(conn)->name);
377 }
379 /* pass ownership back to list; or destroy in case of an error */
380 sdb_object_deref(SDB_OBJ(conn));
381 }
382 return NULL;
383 } /* connection_handler */
385 static int
386 connection_accept(sdb_fe_socket_t *sock, listener_t *listener)
387 {
388 sdb_object_t *obj;
389 int status;
391 obj = SDB_OBJ(sdb_connection_accept(listener->sock_fd));
392 if (! obj)
393 return -1;
395 if (listener->accept && listener->accept(CONN(obj))) {
396 /* accept() is expected to log an error */
397 sdb_object_deref(obj);
398 return -1;
399 }
401 status = sdb_llist_append(sock->open_connections, obj);
402 if (status)
403 sdb_log(SDB_LOG_ERR, "frontend: Failed to append "
404 "connection %s to list of open connections",
405 obj->name);
407 /* hand ownership over to the list; or destroy in case of an error */
408 sdb_object_deref(obj);
409 return status;
410 } /* connection_accept */
412 static int
413 socket_handle_incoming(sdb_fe_socket_t *sock,
414 fd_set *ready, fd_set *exceptions)
415 {
416 sdb_llist_iter_t *iter;
417 size_t i;
419 for (i = 0; i < sock->listeners_num; ++i) {
420 listener_t *listener = sock->listeners + i;
421 if (FD_ISSET(listener->sock_fd, ready))
422 if (connection_accept(sock, listener))
423 continue;
424 }
426 iter = sdb_llist_get_iter(sock->open_connections);
427 if (! iter) {
428 sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
429 "for open connections");
430 return -1;
431 }
433 while (sdb_llist_iter_has_next(iter)) {
434 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
436 if (FD_ISSET(CONN(obj)->fd, exceptions)) {
437 sdb_log(SDB_LOG_INFO, "Exception on fd %d",
438 CONN(obj)->fd);
439 /* close the connection */
440 sdb_llist_iter_remove_current(iter);
441 sdb_object_deref(obj);
442 continue;
443 }
445 if (FD_ISSET(CONN(obj)->fd, ready)) {
446 sdb_llist_iter_remove_current(iter);
447 sdb_channel_write(sock->chan, &obj);
448 }
449 }
450 sdb_llist_iter_destroy(iter);
451 return 0;
452 } /* socket_handle_incoming */
454 /*
455 * public API
456 */
458 sdb_fe_socket_t *
459 sdb_fe_sock_create(void)
460 {
461 sdb_fe_socket_t *sock;
463 sock = calloc(1, sizeof(*sock));
464 if (! sock)
465 return NULL;
467 sock->open_connections = sdb_llist_create();
468 if (! sock->open_connections) {
469 sdb_fe_sock_destroy(sock);
470 return NULL;
471 }
472 return sock;
473 } /* sdb_fe_sock_create */
475 void
476 sdb_fe_sock_destroy(sdb_fe_socket_t *sock)
477 {
478 if (! sock)
479 return;
481 socket_clear(sock);
483 sdb_llist_destroy(sock->open_connections);
484 sock->open_connections = NULL;
485 free(sock);
486 } /* sdb_fe_sock_destroy */
488 int
489 sdb_fe_sock_add_listener(sdb_fe_socket_t *sock, const char *address)
490 {
491 listener_t *listener;
493 if ((! sock) || (! address))
494 return -1;
496 listener = listener_create(sock, address);
497 if (! listener)
498 return -1;
499 return 0;
500 } /* sdb_fe_sock_add_listener */
502 void
503 sdb_fe_sock_clear_listeners(sdb_fe_socket_t *sock)
504 {
505 if (! sock)
506 return;
508 socket_clear(sock);
509 } /* sdb_fe_sock_clear_listeners */
511 int
512 sdb_fe_sock_listen_and_serve(sdb_fe_socket_t *sock, sdb_fe_loop_t *loop)
513 {
514 fd_set sockets;
515 int max_listen_fd = 0;
516 size_t i;
518 pthread_t handler_threads[loop->num_threads];
519 size_t num_threads;
521 if ((! sock) || (! sock->listeners_num) || sock->chan
522 || (! loop) || (loop->num_threads <= 0))
523 return -1;
525 if (! loop->do_loop)
526 return 0;
528 FD_ZERO(&sockets);
529 for (i = 0; i < sock->listeners_num; ++i) {
530 listener_t *listener = sock->listeners + i;
532 if (listener_listen(listener)) {
533 socket_close(sock);
534 return -1;
535 }
537 FD_SET(listener->sock_fd, &sockets);
538 if (listener->sock_fd > max_listen_fd)
539 max_listen_fd = listener->sock_fd;
540 }
542 sock->chan = sdb_channel_create(1024, sizeof(sdb_conn_t *));
543 if (! sock->chan) {
544 socket_close(sock);
545 return -1;
546 }
548 sdb_log(SDB_LOG_INFO, "frontend: Starting %zu connection "
549 "handler thread%s managing %zu listener%s",
550 loop->num_threads, loop->num_threads == 1 ? "" : "s",
551 sock->listeners_num, sock->listeners_num == 1 ? "" : "s");
553 num_threads = loop->num_threads;
554 memset(&handler_threads, 0, sizeof(handler_threads));
555 for (i = 0; i < num_threads; ++i) {
556 errno = 0;
557 if (pthread_create(&handler_threads[i], /* attr = */ NULL,
558 connection_handler, /* arg = */ sock)) {
559 char errbuf[1024];
560 sdb_log(SDB_LOG_ERR, "frontend: Failed to create "
561 "connection handler thread: %s",
562 sdb_strerror(errno, errbuf, sizeof(errbuf)));
563 num_threads = i;
564 break;
565 }
566 }
568 while (loop->do_loop && num_threads) {
569 struct timeval timeout = { 1, 0 }; /* one second */
570 sdb_llist_iter_t *iter;
572 int max_fd = max_listen_fd;
573 fd_set ready;
574 fd_set exceptions;
575 int n;
577 FD_ZERO(&ready);
578 FD_ZERO(&exceptions);
580 ready = sockets;
582 iter = sdb_llist_get_iter(sock->open_connections);
583 if (! iter) {
584 sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
585 "for open connections");
586 break;
587 }
589 while (sdb_llist_iter_has_next(iter)) {
590 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
592 if (CONN(obj)->fd < 0) {
593 sdb_llist_iter_remove_current(iter);
594 sdb_object_deref(obj);
595 continue;
596 }
598 FD_SET(CONN(obj)->fd, &ready);
599 FD_SET(CONN(obj)->fd, &exceptions);
601 if (CONN(obj)->fd > max_fd)
602 max_fd = CONN(obj)->fd;
603 }
604 sdb_llist_iter_destroy(iter);
606 errno = 0;
607 n = select(max_fd + 1, &ready, NULL, &exceptions, &timeout);
608 if (n < 0) {
609 char buf[1024];
611 if (errno == EINTR)
612 continue;
614 sdb_log(SDB_LOG_ERR, "frontend: Failed to monitor sockets: %s",
615 sdb_strerror(errno, buf, sizeof(buf)));
616 break;
617 }
618 else if (! n)
619 continue;
621 /* handle new and open connections */
622 if (socket_handle_incoming(sock, &ready, &exceptions))
623 break;
624 }
626 socket_close(sock);
628 sdb_log(SDB_LOG_INFO, "frontend: Waiting for connection handler threads "
629 "to terminate");
630 if (! sdb_channel_shutdown(sock->chan))
631 for (i = 0; i < num_threads; ++i)
632 pthread_join(handler_threads[i], NULL);
633 /* else: we tried our best; let the operating system clean up */
635 sdb_channel_destroy(sock->chan);
636 sock->chan = NULL;
638 if (! num_threads)
639 return -1;
640 return 0;
641 } /* sdb_fe_sock_listen_and_server */
643 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */