414c90775657294c0408ffb1e8c1eaea78ae8f0d
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 #include "sysdb.h"
29 #include "core/error.h"
30 #include "core/object.h"
31 #include "frontend/sock.h"
33 #include "utils/channel.h"
34 #include "utils/llist.h"
36 #include <assert.h>
38 #include <errno.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
44 #include <unistd.h>
46 #include <fcntl.h>
48 #include <sys/time.h>
49 #include <sys/types.h>
50 #include <sys/select.h>
51 #include <sys/socket.h>
52 #include <sys/un.h>
54 #include <pthread.h>
56 /* name of connection objects */
57 #define CONN_FD_PREFIX "conn#"
58 #define CONN_FD_PLACEHOLDER "XXXXXXX"
60 /*
61 * private data types
62 */
64 typedef struct {
65 int fd;
66 struct sockaddr_storage client_addr;
67 socklen_t client_addr_len;
68 } connection_t;
70 typedef struct {
71 sdb_object_t super;
72 connection_t conn;
73 } connection_obj_t;
74 #define CONN(obj) ((connection_obj_t *)(obj))
76 typedef struct {
77 char *address;
78 int type;
80 int sock_fd;
81 } listener_t;
83 typedef struct {
84 int type;
85 const char *prefix;
87 int (*opener)(listener_t *);
88 } fe_listener_impl_t;
90 struct sdb_fe_socket {
91 listener_t *listeners;
92 size_t listeners_num;
94 sdb_llist_t *open_connections;
96 /* channel used for communication between main
97 * and connection handler threads */
98 sdb_channel_t *chan;
99 };
101 /*
102 * connection management functions
103 */
105 static int
106 open_unix_sock(listener_t *listener)
107 {
108 struct sockaddr_un sa;
109 int status;
111 listener->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
112 if (listener->sock_fd < 0) {
113 char buf[1024];
114 sdb_log(SDB_LOG_ERR, "frontend: Failed to open UNIX socket %s: %s",
115 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
116 return -1;
117 }
119 memset(&sa, 0, sizeof(sa));
120 sa.sun_family = AF_UNIX;
121 strncpy(sa.sun_path, listener->address + strlen("unix:"),
122 sizeof(sa.sun_path));
124 status = bind(listener->sock_fd, (struct sockaddr *)&sa, sizeof(sa));
125 if (status) {
126 char buf[1024];
127 sdb_log(SDB_LOG_ERR, "frontend: Failed to bind to UNIX socket %s: %s",
128 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
129 return -1;
130 }
131 return 0;
132 } /* open_unix_sock */
134 /*
135 * private variables
136 */
138 /* the enum has to be sorted the same as the implementations array
139 * to ensure that the type may be used as index into the array */
140 enum {
141 LISTENER_UNIXSOCK = 0,
142 };
143 static fe_listener_impl_t listener_impls[] = {
144 { LISTENER_UNIXSOCK, "unix", open_unix_sock },
145 };
147 /*
148 * private helper functions
149 */
151 static int
152 get_type(const char *address)
153 {
154 char *sep;
155 size_t len;
156 size_t i;
158 sep = strchr(address, (int)':');
159 if (! sep)
160 return -1;
162 assert(sep > address);
163 len = (size_t)(sep - address);
165 for (i = 0; i < SDB_STATIC_ARRAY_LEN(listener_impls); ++i) {
166 fe_listener_impl_t *impl = listener_impls + i;
168 if (!strncmp(address, impl->prefix, len)) {
169 assert(impl->type == (int)i);
170 return impl->type;
171 }
172 }
173 return -1;
174 } /* get_type */
176 static void
177 listener_destroy(listener_t *listener)
178 {
179 if (! listener)
180 return;
182 if (listener->sock_fd >= 0)
183 close(listener->sock_fd);
184 listener->sock_fd = -1;
186 if (listener->address)
187 free(listener->address);
188 } /* listener_destroy */
190 static listener_t *
191 listener_create(sdb_fe_socket_t *sock, const char *address)
192 {
193 listener_t *listener;
194 int type;
196 type = get_type(address);
197 if (type < 0) {
198 sdb_log(SDB_LOG_ERR, "frontend: Unsupported address type specified "
199 "in listen address '%s'", address);
200 return NULL;
201 }
203 listener = realloc(sock->listeners,
204 sock->listeners_num * sizeof(*sock->listeners));
205 if (! listener) {
206 char buf[1024];
207 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
208 sdb_strerror(errno, buf, sizeof(buf)));
209 return NULL;
210 }
212 sock->listeners = listener;
213 listener = sock->listeners + sock->listeners_num;
215 listener->sock_fd = -1;
216 listener->address = strdup(address);
217 if (! listener->address) {
218 char buf[1024];
219 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate memory: %s",
220 sdb_strerror(errno, buf, sizeof(buf)));
221 listener_destroy(listener);
222 return NULL;
223 }
224 listener->type = type;
226 if (listener_impls[type].opener(listener)) {
227 /* prints error */
228 listener_destroy(listener);
229 return NULL;
230 }
232 ++sock->listeners_num;
233 return listener;
234 } /* listener_create */
236 static int
237 listener_listen(listener_t *listener)
238 {
239 assert(listener);
241 /* try to reopen */
242 if (listener->sock_fd < 0)
243 if (listener_impls[listener->type].opener(listener))
244 return -1;
245 assert(listener->sock_fd >= 0);
247 if (listen(listener->sock_fd, /* backlog = */ 32)) {
248 char buf[1024];
249 sdb_log(SDB_LOG_ERR, "frontend: Failed to listen on socket %s: %s",
250 listener->address, sdb_strerror(errno, buf, sizeof(buf)));
251 return -1;
252 }
253 return 0;
254 } /* listener_listen */
256 static void
257 listener_close(listener_t *listener)
258 {
259 assert(listener);
261 if (listener->sock_fd < 0)
262 return;
264 close(listener->sock_fd);
265 listener->sock_fd = -1;
266 } /* listener_close */
268 static void
269 socket_close(sdb_fe_socket_t *sock)
270 {
271 size_t i;
273 assert(sock);
274 for (i = 0; i < sock->listeners_num; ++i)
275 listener_close(sock->listeners + i);
276 } /* socket_close */
278 /*
279 * private data types
280 */
282 static int
283 connection_init(sdb_object_t *obj, va_list ap)
284 {
285 connection_t *conn;
286 int sock_fd;
287 int sock_fl;
289 assert(obj);
290 conn = &CONN(obj)->conn;
292 sock_fd = va_arg(ap, int);
294 conn->client_addr_len = sizeof(conn->client_addr);
295 conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
296 &conn->client_addr_len);
298 if (conn->fd < 0) {
299 char buf[1024];
300 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
301 "connection: %s", sdb_strerror(errno,
302 buf, sizeof(buf)));
303 return -1;
304 }
306 if (conn->client_addr.ss_family != AF_UNIX) {
307 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
308 "unexpected family type %d", conn->client_addr.ss_family);
309 return -1;
310 }
312 sock_fl = fcntl(conn->fd, F_GETFL);
313 if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
314 char buf[1024];
315 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
316 "to non-blocking mode: %s", conn->fd,
317 sdb_strerror(errno, buf, sizeof(buf)));
318 return -1;
319 }
321 sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
322 conn->fd);
324 /* update the object name */
325 snprintf(obj->name + strlen(CONN_FD_PREFIX),
326 strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
327 return 0;
328 } /* connection_init */
330 static void
331 connection_destroy(sdb_object_t *obj)
332 {
333 connection_t *conn;
335 assert(obj);
336 conn = &CONN(obj)->conn;
338 sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection on fd=%i", conn->fd);
339 close(conn->fd);
340 conn->fd = -1;
341 } /* connection_destroy */
343 static sdb_type_t connection_type = {
344 /* size = */ sizeof(connection_obj_t),
345 /* init = */ connection_init,
346 /* destroy = */ connection_destroy,
347 };
349 /*
350 * connection handler functions
351 */
353 /* returns negative value on error, 0 on EOF, number of packets else */
354 static int
355 connection_read(int fd)
356 {
357 int n = 0;
359 while (42) {
360 int32_t cmd;
361 ssize_t status;
363 errno = 0;
364 status = read(fd, &cmd, sizeof(cmd));
365 if (status < 0) {
366 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
367 return n + 1;
368 return (int)status;
369 }
370 else if (! status) /* EOF */
371 return 0;
373 /* XXX */
374 sdb_log(SDB_LOG_DEBUG, "frontend: read command %i from fd=%i",
375 cmd, fd);
376 ++n;
377 }
379 return n + 1;
380 } /* connection_read */
382 static void *
383 connection_handler(void *data)
384 {
385 sdb_fe_socket_t *sock = data;
387 assert(sock);
389 while (42) {
390 struct timespec timeout = { 0, 500000000 }; /* .5 seconds */
391 connection_obj_t *conn;
392 int status;
394 errno = 0;
395 status = sdb_channel_select(sock->chan, /* read */ NULL, &conn,
396 /* write */ NULL, NULL, &timeout);
397 if (status) {
398 char buf[1024];
400 if (errno == ETIMEDOUT)
401 continue;
402 if (errno == EBADF) /* channel shut down */
403 break;
405 sdb_log(SDB_LOG_ERR, "frontend: Failed to read from channel: %s",
406 sdb_strerror(errno, buf, sizeof(buf)));
407 continue;
408 }
410 status = connection_read(conn->conn.fd);
411 if (status <= 0) {
412 /* error or EOF -> close connection */
413 sdb_object_deref(SDB_OBJ(conn));
414 }
415 else {
416 if (sdb_llist_append(sock->open_connections, SDB_OBJ(conn))) {
417 sdb_log(SDB_LOG_ERR, "frontend: Failed to re-append "
418 "connection %s to list of open connections",
419 SDB_OBJ(conn)->name);
420 }
422 /* pass ownership back to list; or destroy in case of an error */
423 sdb_object_deref(SDB_OBJ(conn));
424 }
425 }
426 return NULL;
427 } /* connection_handler */
429 static int
430 connection_accept(sdb_fe_socket_t *sock, listener_t *listener)
431 {
432 sdb_object_t *obj;
434 /* the placeholder will be replaced with the accepted file
435 * descriptor when initializing the object */
436 obj = sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
437 connection_type, listener->sock_fd);
438 if (! obj)
439 return -1;
441 if (sdb_llist_append(sock->open_connections, obj)) {
442 sdb_log(SDB_LOG_ERR, "frontend: Failed to append "
443 "connection %s to list of open connections",
444 obj->name);
445 sdb_object_deref(obj);
446 return -1;
447 }
449 /* hand ownership over to the list */
450 sdb_object_deref(obj);
451 return 0;
452 } /* connection_accept */
454 static int
455 socket_handle_incoming(sdb_fe_socket_t *sock,
456 fd_set *ready, fd_set *exceptions)
457 {
458 sdb_llist_iter_t *iter;
459 size_t i;
461 for (i = 0; i < sock->listeners_num; ++i) {
462 listener_t *listener = sock->listeners + i;
463 if (FD_ISSET(listener->sock_fd, ready))
464 if (connection_accept(sock, listener))
465 continue;
466 }
468 iter = sdb_llist_get_iter(sock->open_connections);
469 if (! iter) {
470 sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
471 "for open connections");
472 return -1;
473 }
475 while (sdb_llist_iter_has_next(iter)) {
476 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
478 if (FD_ISSET(CONN(obj)->conn.fd, exceptions))
479 sdb_log(SDB_LOG_INFO, "Exception on fd %d",
480 CONN(obj)->conn.fd);
482 if (FD_ISSET(CONN(obj)->conn.fd, ready)) {
483 sdb_llist_iter_remove_current(iter);
484 sdb_channel_write(sock->chan, &obj);
485 }
486 }
487 sdb_llist_iter_destroy(iter);
488 return 0;
489 } /* socket_handle_incoming */
491 /*
492 * public API
493 */
495 sdb_fe_socket_t *
496 sdb_fe_sock_create(void)
497 {
498 sdb_fe_socket_t *sock;
500 sock = calloc(1, sizeof(*sock));
501 if (! sock)
502 return NULL;
504 sock->open_connections = sdb_llist_create();
505 if (! sock->open_connections) {
506 sdb_fe_sock_destroy(sock);
507 return NULL;
508 }
509 return sock;
510 } /* sdb_fe_sock_create */
512 void
513 sdb_fe_sock_destroy(sdb_fe_socket_t *sock)
514 {
515 size_t i;
517 if (! sock)
518 return;
520 for (i = 0; i < sock->listeners_num; ++i) {
521 listener_destroy(sock->listeners + i);
522 }
523 if (sock->listeners)
524 free(sock->listeners);
525 sock->listeners = NULL;
527 sdb_llist_destroy(sock->open_connections);
528 sock->open_connections = NULL;
529 free(sock);
530 } /* sdb_fe_sock_destroy */
532 int
533 sdb_fe_sock_add_listener(sdb_fe_socket_t *sock, const char *address)
534 {
535 listener_t *listener;
537 if ((! sock) || (! address))
538 return -1;
540 listener = listener_create(sock, address);
541 if (! listener)
542 return -1;
543 return 0;
544 } /* sdb_fe_sock_add_listener */
546 int
547 sdb_fe_sock_listen_and_serve(sdb_fe_socket_t *sock, sdb_fe_loop_t *loop)
548 {
549 fd_set sockets;
550 int max_listen_fd = 0;
551 size_t i;
553 /* XXX: make the number of threads configurable */
554 pthread_t handler_threads[5];
556 if ((! sock) || (! sock->listeners_num) || (! loop) || sock->chan)
557 return -1;
559 FD_ZERO(&sockets);
560 for (i = 0; i < sock->listeners_num; ++i) {
561 listener_t *listener = sock->listeners + i;
563 if (listener_listen(listener)) {
564 socket_close(sock);
565 return -1;
566 }
568 FD_SET(listener->sock_fd, &sockets);
569 if (listener->sock_fd > max_listen_fd)
570 max_listen_fd = listener->sock_fd;
571 }
573 sock->chan = sdb_channel_create(1024, sizeof(connection_obj_t *));
574 if (! sock->chan) {
575 socket_close(sock);
576 return -1;
577 }
579 memset(&handler_threads, 0, sizeof(handler_threads));
580 /* XXX: error handling */
581 for (i = 0; i < SDB_STATIC_ARRAY_LEN(handler_threads); ++i)
582 pthread_create(&handler_threads[i], /* attr = */ NULL,
583 connection_handler, /* arg = */ sock);
585 while (loop->do_loop) {
586 struct timeval timeout = { 1, 0 }; /* one second */
587 sdb_llist_iter_t *iter;
589 int max_fd = max_listen_fd;
590 fd_set ready;
591 fd_set exceptions;
592 int n;
594 FD_ZERO(&ready);
595 FD_ZERO(&exceptions);
597 ready = sockets;
599 iter = sdb_llist_get_iter(sock->open_connections);
600 if (! iter) {
601 sdb_log(SDB_LOG_ERR, "frontend: Failed to acquire iterator "
602 "for open connections");
603 break;
604 }
606 while (sdb_llist_iter_has_next(iter)) {
607 sdb_object_t *obj = sdb_llist_iter_get_next(iter);
608 FD_SET(CONN(obj)->conn.fd, &ready);
609 FD_SET(CONN(obj)->conn.fd, &exceptions);
611 if (CONN(obj)->conn.fd > max_fd)
612 max_fd = CONN(obj)->conn.fd;
613 }
614 sdb_llist_iter_destroy(iter);
616 errno = 0;
617 n = select(max_fd + 1, &ready, NULL, &exceptions, &timeout);
618 if (n < 0) {
619 char buf[1024];
621 if (errno == EINTR)
622 continue;
624 sdb_log(SDB_LOG_ERR, "frontend: Failed to monitor sockets: %s",
625 sdb_strerror(errno, buf, sizeof(buf)));
626 break;
627 }
628 else if (! n)
629 continue;
631 /* handle new and open connections */
632 if (socket_handle_incoming(sock, &ready, &exceptions))
633 break;
634 }
636 socket_close(sock);
638 sdb_log(SDB_LOG_INFO, "frontend: Waiting for connection handler threads "
639 "to terminate");
640 if (! sdb_channel_shutdown(sock->chan))
641 for (i = 0; i < SDB_STATIC_ARRAY_LEN(handler_threads); ++i)
642 pthread_join(handler_threads[i], NULL);
643 /* else: we tried our best; let the operating system clean up */
645 sdb_channel_destroy(sock->chan);
646 sock->chan = NULL;
647 return 0;
648 } /* sdb_fe_sock_listen_and_server */
650 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */