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/strbuf.h"
42 #include <assert.h>
43 #include <errno.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
49 #include <unistd.h>
51 #include <sys/time.h>
52 #include <sys/types.h>
53 #include <sys/select.h>
54 #include <sys/socket.h>
55 #include <sys/un.h>
57 #include <pthread.h>
59 /*
60 * private data types
61 */
63 typedef struct {
64 char *address;
65 int type;
67 int sock_fd;
68 } listener_t;
70 typedef struct {
71 int type;
72 const char *prefix;
74 int (*opener)(listener_t *);
75 void (*closer)(listener_t *);
76 } fe_listener_impl_t;
78 struct sdb_fe_socket {
79 listener_t *listeners;
80 size_t listeners_num;
82 sdb_llist_t *open_connections;
84 /* channel used for communication between main
85 * and connection handler threads */
86 sdb_channel_t *chan;
87 };
89 /*
90 * connection management functions
91 */
93 static int
94 open_unix_sock(listener_t *listener)
95 {
96 struct sockaddr_un sa;
97 int status;
99 listener->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
100 if (listener->sock_fd < 0) {
101 char buf[1024];
102 sdb_log(SDB_LOG_ERR, "frontend: Failed to open UNIX socket %s: %s",
103 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
104 return -1;
105 }
107 memset(&sa, 0, sizeof(sa));
108 sa.sun_family = AF_UNIX;
109 strncpy(sa.sun_path, listener->address + strlen("unix:"),
110 sizeof(sa.sun_path));
112 if (unlink(listener->address + strlen("unix:")) && (errno != ENOENT)) {
113 char errbuf[1024];
114 sdb_log(SDB_LOG_WARNING, "frontend: Failed to remove stale UNIX "
115 "socket %s: %s", listener->address + strlen("unix:"),
116 sdb_strerror(errno, errbuf, sizeof(errbuf)));
117 }
119 status = bind(listener->sock_fd, (struct sockaddr *)&sa, sizeof(sa));
120 if (status) {
121 char buf[1024];
122 sdb_log(SDB_LOG_ERR, "frontend: Failed to bind to UNIX socket %s: %s",
123 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
124 return -1;
125 }
126 return 0;
127 } /* open_unix_sock */
129 static void
130 close_unix_sock(listener_t *listener)
131 {
132 assert(listener);
133 if (! listener->address)
134 return;
136 if (listener->sock_fd >= 0)
137 close(listener->sock_fd);
138 listener->sock_fd = -1;
140 unlink(listener->address + strlen("unix:"));
141 } /* close_unix_sock */
143 /*
144 * private variables
145 */
147 /* the enum has to be sorted the same as the implementations array
148 * to ensure that the type may be used as index into the array */
149 enum {
150 LISTENER_UNIXSOCK = 0,
151 };
152 static fe_listener_impl_t listener_impls[] = {
153 { LISTENER_UNIXSOCK, "unix", open_unix_sock, close_unix_sock },
154 };
156 /*
157 * private helper functions
158 */
160 static int
161 listener_listen(listener_t *listener)
162 {
163 assert(listener);
165 /* try to reopen */
166 if (listener->sock_fd < 0)
167 if (listener_impls[listener->type].opener(listener))
168 return -1;
169 assert(listener->sock_fd >= 0);
171 if (listen(listener->sock_fd, /* backlog = */ 32)) {
172 char buf[1024];
173 sdb_log(SDB_LOG_ERR, "frontend: Failed to listen on socket %s: %s",
174 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
175 return -1;
176 }
177 return 0;
178 } /* listener_listen */
180 static void
181 listener_close(listener_t *listener)
182 {
183 assert(listener);
185 if (listener_impls[listener->type].closer)
186 listener_impls[listener->type].closer(listener);
188 if (listener->sock_fd >= 0)
189 close(listener->sock_fd);
190 listener->sock_fd = -1;
191 } /* listener_close */
193 static int
194 get_type(const char *address)
195 {
196 char *sep;
197 size_t len;
198 size_t i;
200 sep = strchr(address, (int)':');
201 if (! sep)
202 return -1;
204 assert(sep > address);
205 len = (size_t)(sep - address);
207 for (i = 0; i < SDB_STATIC_ARRAY_LEN(listener_impls); ++i) {
208 fe_listener_impl_t *impl = listener_impls + i;
210 if (!strncmp(address, impl->prefix, len)) {
211 assert(impl->type == (int)i);
212 return impl->type;
213 }
214 }
215 return -1;
216 } /* get_type */
218 static void
219 listener_destroy(listener_t *listener)
220 {
221 if (! listener)
222 return;
224 listener_close(listener);
226 if (listener->address)
227 free(listener->address);
228 listener->address = NULL;
229 } /* listener_destroy */
231 static listener_t *
232 listener_create(sdb_fe_socket_t *sock, const char *address)
233 {
234 listener_t *listener;
235 int type;
237 type = get_type(address);
238 if (type < 0) {
239 sdb_log(SDB_LOG_ERR, "frontend: Unsupported address type specified "
240 "in listen address '%s'", address);
241 return NULL;
242 }
244 listener = realloc(sock->listeners,
245 (sock->listeners_num + 1) * sizeof(*sock->listeners));
246 if (! listener) {
247 char buf[1024];
248 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
249 sdb_strerror(errno, buf, sizeof(buf)));
250 return NULL;
251 }
253 sock->listeners = listener;
254 listener = sock->listeners + sock->listeners_num;
256 listener->sock_fd = -1;
257 listener->address = strdup(address);
258 if (! listener->address) {
259 char buf[1024];
260 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
261 sdb_strerror(errno, buf, sizeof(buf)));
262 listener_destroy(listener);
263 return NULL;
264 }
265 listener->type = type;
267 if (listener_impls[type].opener(listener)) {
268 /* prints error */
269 listener_destroy(listener);
270 return NULL;
271 }
273 ++sock->listeners_num;
274 return listener;
275 } /* listener_create */
277 static void
278 socket_close(sdb_fe_socket_t *sock)
279 {
280 size_t i;
282 assert(sock);
283 for (i = 0; i < sock->listeners_num; ++i)
284 listener_close(sock->listeners + i);
285 } /* socket_close */
287 /*
288 * connection handler functions
289 */
291 static void *
292 connection_handler(void *data)
293 {
294 sdb_fe_socket_t *sock = data;
296 assert(sock);
298 while (42) {
299 struct timespec timeout = { 0, 500000000 }; /* .5 seconds */
300 sdb_conn_t *conn;
301 int status;
303 errno = 0;
304 status = sdb_channel_select(sock->chan, /* read */ NULL, &conn,
305 /* write */ NULL, NULL, &timeout);
306 if (status) {
307 char buf[1024];
309 if (errno == ETIMEDOUT)
310 continue;
311 if (errno == EBADF) /* channel shut down */
312 break;
314 sdb_log(SDB_LOG_ERR, "frontend: Failed to read from channel: %s",
315 sdb_strerror(errno, buf, sizeof(buf)));
316 continue;
317 }
319 status = (int)sdb_connection_read(conn);
320 if (status <= 0) {
321 /* error or EOF -> close connection */
322 sdb_object_deref(SDB_OBJ(conn));
323 continue;
324 }
326 /* return the connection to the main loop */
327 if (sdb_llist_append(sock->open_connections, SDB_OBJ(conn))) {
328 sdb_log(SDB_LOG_ERR, "frontend: Failed to re-append "
329 "connection %s to list of open connections",
330 SDB_OBJ(conn)->name);
331 }
333 /* pass ownership back to list; or destroy in case of an error */
334 sdb_object_deref(SDB_OBJ(conn));
335 }
336 return NULL;
337 } /* connection_handler */
339 static int
340 connection_accept(sdb_fe_socket_t *sock, listener_t *listener)
341 {
342 sdb_object_t *obj;
343 int status;
345 obj = SDB_OBJ(sdb_connection_accept(listener->sock_fd));
346 if (! obj)
347 return -1;
349 status = sdb_llist_append(sock->open_connections, obj);
350 if (status)
351 sdb_log(SDB_LOG_ERR, "frontend: Failed to append "
352 "connection %s to list of open connections",
353 obj->name);
355 /* hand ownership over to the list; or destroy in case of an error */
356 sdb_object_deref(obj);
357 return status;
358 } /* connection_accept */
360 static int
361 socket_handle_incoming(sdb_fe_socket_t *sock,
362 fd_set *ready, fd_set *exceptions)
363 {
364 sdb_llist_iter_t *iter;
365 size_t i;
367 for (i = 0; i < sock->listeners_num; ++i) {
368 listener_t *listener = sock->listeners + i;
369 if (FD_ISSET(listener->sock_fd, ready))
370 if (connection_accept(sock, listener))
371 continue;
372 }
374 iter = sdb_llist_get_iter(sock->open_connections);
375 if (! iter) {
376 sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
377 "for open connections");
378 return -1;
379 }
381 while (sdb_llist_iter_has_next(iter)) {
382 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
384 if (FD_ISSET(CONN(obj)->fd, exceptions))
385 sdb_log(SDB_LOG_INFO, "Exception on fd %d",
386 CONN(obj)->fd);
388 if (FD_ISSET(CONN(obj)->fd, ready)) {
389 sdb_llist_iter_remove_current(iter);
390 sdb_channel_write(sock->chan, &obj);
391 }
392 }
393 sdb_llist_iter_destroy(iter);
394 return 0;
395 } /* socket_handle_incoming */
397 /*
398 * public API
399 */
401 sdb_fe_socket_t *
402 sdb_fe_sock_create(void)
403 {
404 sdb_fe_socket_t *sock;
406 sock = calloc(1, sizeof(*sock));
407 if (! sock)
408 return NULL;
410 sock->open_connections = sdb_llist_create();
411 if (! sock->open_connections) {
412 sdb_fe_sock_destroy(sock);
413 return NULL;
414 }
415 return sock;
416 } /* sdb_fe_sock_create */
418 void
419 sdb_fe_sock_destroy(sdb_fe_socket_t *sock)
420 {
421 size_t i;
423 if (! sock)
424 return;
426 for (i = 0; i < sock->listeners_num; ++i) {
427 listener_destroy(sock->listeners + i);
428 }
429 if (sock->listeners)
430 free(sock->listeners);
431 sock->listeners = NULL;
433 sdb_llist_destroy(sock->open_connections);
434 sock->open_connections = NULL;
435 free(sock);
436 } /* sdb_fe_sock_destroy */
438 int
439 sdb_fe_sock_add_listener(sdb_fe_socket_t *sock, const char *address)
440 {
441 listener_t *listener;
443 if ((! sock) || (! address))
444 return -1;
446 listener = listener_create(sock, address);
447 if (! listener)
448 return -1;
449 return 0;
450 } /* sdb_fe_sock_add_listener */
452 int
453 sdb_fe_sock_listen_and_serve(sdb_fe_socket_t *sock, sdb_fe_loop_t *loop)
454 {
455 fd_set sockets;
456 int max_listen_fd = 0;
457 size_t i;
459 pthread_t handler_threads[loop->num_threads];
460 size_t num_threads;
462 if ((! sock) || (! sock->listeners_num) || sock->chan
463 || (! loop) || (loop->num_threads <= 0))
464 return -1;
466 if (! loop->do_loop)
467 return 0;
469 FD_ZERO(&sockets);
470 for (i = 0; i < sock->listeners_num; ++i) {
471 listener_t *listener = sock->listeners + i;
473 if (listener_listen(listener)) {
474 socket_close(sock);
475 return -1;
476 }
478 FD_SET(listener->sock_fd, &sockets);
479 if (listener->sock_fd > max_listen_fd)
480 max_listen_fd = listener->sock_fd;
481 }
483 sock->chan = sdb_channel_create(1024, sizeof(sdb_conn_t *));
484 if (! sock->chan) {
485 socket_close(sock);
486 return -1;
487 }
489 sdb_log(SDB_LOG_INFO, "frontend: Starting %d connection "
490 "handler thread%s managing %d listener%s",
491 loop->num_threads, loop->num_threads == 1 ? "" : "s",
492 sock->listeners_num, sock->listeners_num == 1 ? "" : "s");
494 num_threads = loop->num_threads;
495 memset(&handler_threads, 0, sizeof(handler_threads));
496 for (i = 0; i < num_threads; ++i) {
497 errno = 0;
498 if (pthread_create(&handler_threads[i], /* attr = */ NULL,
499 connection_handler, /* arg = */ sock)) {
500 char errbuf[1024];
501 sdb_log(SDB_LOG_ERR, "frontend: Failed to create "
502 "connection handler thread: %s",
503 sdb_strerror(errno, errbuf, sizeof(errbuf)));
504 num_threads = i;
505 break;
506 }
507 }
509 while (loop->do_loop && num_threads) {
510 struct timeval timeout = { 1, 0 }; /* one second */
511 sdb_llist_iter_t *iter;
513 int max_fd = max_listen_fd;
514 fd_set ready;
515 fd_set exceptions;
516 int n;
518 FD_ZERO(&ready);
519 FD_ZERO(&exceptions);
521 ready = sockets;
523 iter = sdb_llist_get_iter(sock->open_connections);
524 if (! iter) {
525 sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
526 "for open connections");
527 break;
528 }
530 while (sdb_llist_iter_has_next(iter)) {
531 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
532 FD_SET(CONN(obj)->fd, &ready);
533 FD_SET(CONN(obj)->fd, &exceptions);
535 if (CONN(obj)->fd > max_fd)
536 max_fd = CONN(obj)->fd;
537 }
538 sdb_llist_iter_destroy(iter);
540 errno = 0;
541 n = select(max_fd + 1, &ready, NULL, &exceptions, &timeout);
542 if (n < 0) {
543 char buf[1024];
545 if (errno == EINTR)
546 continue;
548 sdb_log(SDB_LOG_ERR, "frontend: Failed to monitor sockets: %s",
549 sdb_strerror(errno, buf, sizeof(buf)));
550 break;
551 }
552 else if (! n)
553 continue;
555 /* handle new and open connections */
556 if (socket_handle_incoming(sock, &ready, &exceptions))
557 break;
558 }
560 socket_close(sock);
562 sdb_log(SDB_LOG_INFO, "frontend: Waiting for connection handler threads "
563 "to terminate");
564 if (! sdb_channel_shutdown(sock->chan))
565 for (i = 0; i < num_threads; ++i)
566 pthread_join(handler_threads[i], NULL);
567 /* else: we tried our best; let the operating system clean up */
569 sdb_channel_destroy(sock->chan);
570 sock->chan = NULL;
572 if (! num_threads)
573 return -1;
574 return 0;
575 } /* sdb_fe_sock_listen_and_server */
577 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */