1 /*
2  * Copyright (c) 2016, 2019, 2020-2021 Tracey Emery <tracey@traceyemery.net>
3  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
4  * Copyright (c) 2013 David Gwynne <dlg@openbsd.org>
5  * Copyright (c) 2013 Florian Obser <florian@openbsd.org>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include <sys/param.h>
21 #include <sys/ioctl.h>
22 #include <sys/queue.h>
23 #include <sys/wait.h>
24 #include <sys/uio.h>
25 #include <sys/resource.h>
26 #include <sys/socket.h>
27 #include <sys/stat.h>
28 #include <sys/time.h>
29 #include <sys/types.h>
30 #include <sys/mman.h>
31 #include <sys/un.h>
32 
33 #include <net/if.h>
34 #include <netinet/in.h>
35 
36 #include <errno.h>
37 #include <event.h>
38 #include <fcntl.h>
39 #include <ifaddrs.h>
40 #include <imsg.h>
41 #include <limits.h>
42 #include <netdb.h>
43 #include <poll.h>
44 #include <pwd.h>
45 #include <stddef.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <unistd.h>
50 #include <util.h>
51 
52 #include "got_error.h"
53 #include "got_opentemp.h"
54 
55 #include "proc.h"
56 #include "gotwebd.h"
57 
58 #define SOCKS_BACKLOG 5
59 #define MAXIMUM(a, b)	(((a) > (b)) ? (a) : (b))
60 
61 
62 volatile int client_cnt;
63 
64 struct timeval	timeout = { TIMEOUT_DEFAULT, 0 };
65 
66 void	 sockets_sighdlr(int, short, void *);
67 void	 sockets_run(struct privsep *, struct privsep_proc *, void *);
68 void	 sockets_launch(void);
69 void	 sockets_purge(struct gotwebd *);
70 void	 sockets_accept_paused(int, short, void *);
71 void	 sockets_dup_new_socket(struct socket *, struct socket *);
72 void	 sockets_rlimit(int);
73 
74 
75 int	 sockets_dispatch_gotwebd(int, struct privsep_proc *, struct imsg *);
76 int	 sockets_unix_socket_listen(struct privsep *, struct socket *);
77 int	 sockets_create_socket(struct addresslist *, in_port_t);
78 int	 sockets_accept_reserve(int, struct sockaddr *, socklen_t *, int,
79 	    volatile int *);
80 
81 struct socket
82 	*sockets_conf_new_socket(struct gotwebd *, struct server *, int, int,
83 	    int);
84 
85 int cgi_inflight = 0;
86 
87 static struct privsep_proc procs[] = {
88 	{ "gotwebd",	PROC_GOTWEBD,	sockets_dispatch_gotwebd  },
89 };
90 
91 void
92 sockets(struct privsep *ps, struct privsep_proc *p)
93 {
94 	proc_run(ps, p, procs, nitems(procs), sockets_run, NULL);
95 }
96 
97 void
98 sockets_run(struct privsep *ps, struct privsep_proc *p, void *arg)
99 {
100 	if (config_init(ps->ps_env) == -1)
101 		fatal("failed to initialize configuration");
102 
103 	p->p_shutdown = sockets_shutdown;
104 
105 	sockets_rlimit(-1);
106 
107 	signal_del(&ps->ps_evsigchld);
108 	signal_set(&ps->ps_evsigchld, SIGCHLD, sockets_sighdlr, ps);
109 	signal_add(&ps->ps_evsigchld, NULL);
110 
111 #ifndef PROFILE
112 	if (pledge("stdio rpath wpath cpath inet recvfd proc exec sendfd",
113 	    NULL) == -1)
114 		fatal("pledge");
115 #endif
116 }
117 
118 void
119 sockets_parse_sockets(struct gotwebd *env)
120 {
121 	struct server *srv;
122 	struct socket *sock, *new_sock = NULL;
123 	struct address *a;
124 	int sock_id = 0, ipv4 = 0, ipv6 = 0;
125 
126 	TAILQ_FOREACH(srv, env->servers, entry) {
127 		if (srv->unix_socket) {
128 			sock_id++;
129 			new_sock = sockets_conf_new_socket(env, srv,
130 			    sock_id, UNIX, 0);
131 			TAILQ_INSERT_TAIL(env->sockets, new_sock, entry);
132 		}
133 
134 		if (srv->fcgi_socket) {
135 			sock_id++;
136 			new_sock = sockets_conf_new_socket(env, srv,
137 			    sock_id, FCGI, 0);
138 			TAILQ_INSERT_TAIL(env->sockets, new_sock, entry);
139 
140 			/* add ipv6 children */
141 			TAILQ_FOREACH(sock, env->sockets, entry) {
142 				ipv4 = ipv6 = 0;
143 
144 				TAILQ_FOREACH(a, sock->conf.al, entry) {
145 					if (a->ss.ss_family == AF_INET)
146 						ipv4 = 1;
147 					if (a->ss.ss_family == AF_INET6)
148 						ipv6 = 1;
149 				}
150 
151 				/* create ipv6 sock */
152 				if (ipv4 == 1 && ipv6 == 1) {
153 					sock_id++;
154 					sock->conf.child_id = sock_id;
155 					new_sock = sockets_conf_new_socket(env,
156 					    srv, sock_id, FCGI, 1);
157 					sockets_dup_new_socket(sock, new_sock);
158 					TAILQ_INSERT_TAIL(env->sockets,
159 					    new_sock, entry);
160 					continue;
161 				}
162 			}
163 		}
164 	}
165 }
166 
167 void
168 sockets_dup_new_socket(struct socket *p_sock, struct socket *sock)
169 {
170 	struct address *a, *acp;
171 	int n;
172 
173 	sock->conf.parent_id = p_sock->conf.id;
174 	sock->conf.ipv4 = 0;
175 	sock->conf.ipv6 = 1;
176 
177 	memcpy(&sock->conf.srv_name, p_sock->conf.srv_name,
178 	    sizeof(sock->conf.srv_name));
179 
180 	n = snprintf(sock->conf.name, GOTWEBD_MAXTEXT, "%s_child",
181 	    p_sock->conf.srv_name);
182 	if (n < 0) {
183 		free(p_sock->conf.al);
184 		free(p_sock);
185 		free(sock->conf.al);
186 		free(sock);
187 		fatalx("%s: snprintf", __func__);
188 	}
189 
190 	TAILQ_FOREACH(a, p_sock->conf.al, entry) {
191 		if (a->ss.ss_family == AF_INET)
192 			continue;
193 
194 		if ((acp = calloc(1, sizeof(*acp))) == NULL)
195 			fatal("%s: calloc", __func__);
196 		memcpy(&acp->ss, &a->ss, sizeof(acp->ss));
197 		acp->ipproto = a->ipproto;
198 		acp->prefixlen = a->prefixlen;
199 		acp->port = a->port;
200 		if (strlen(a->ifname) != 0) {
201 			if (strlcpy(acp->ifname, a->ifname,
202 			    sizeof(acp->ifname)) >= sizeof(acp->ifname)) {
203 				fatalx("%s: interface name truncated",
204 				    __func__);
205 			}
206 		}
207 
208 		TAILQ_INSERT_TAIL(sock->conf.al, acp, entry);
209 	}
210 }
211 
212 struct socket *
213 sockets_conf_new_socket(struct gotwebd *env, struct server *srv, int id,
214     int type, int is_dup)
215 {
216 	struct socket *sock;
217 	struct address *a, *acp;
218 	int n;
219 
220 	if ((sock = calloc(1, sizeof(*sock))) == NULL)
221 		fatalx("%s: calloc", __func__);
222 
223 	if ((sock->conf.al = calloc(1, sizeof(*sock->conf.al))) == NULL) {
224 		free(sock);
225 		fatalx("%s: calloc", __func__);
226 	}
227 	TAILQ_INIT(sock->conf.al);
228 
229 	sock->conf.parent_id = 0;
230 	sock->conf.id = id;
231 
232 	sock->fd = -1;
233 
234 	sock->conf.type = type;
235 
236 	if (type == UNIX) {
237 		if (strlcpy(sock->conf.unix_socket_name,
238 		    srv->unix_socket_name,
239 		    sizeof(sock->conf.unix_socket_name)) >=
240 		    sizeof(sock->conf.unix_socket_name)) {
241 			free(sock->conf.al);
242 			free(sock);
243 			fatalx("%s: strlcpy", __func__);
244 		}
245 	} else
246 		sock->conf.ipv4 = 1;
247 
248 	sock->conf.fcgi_socket_port = srv->fcgi_socket_port;
249 
250 	if (is_dup)
251 		goto done;
252 
253 	n = snprintf(sock->conf.name, GOTWEBD_MAXTEXT, "%s_parent",
254 	    srv->name);
255 	if (n < 0) {
256 		free(sock->conf.al);
257 		free(sock);
258 		fatalx("%s: snprintf", __func__);
259 	}
260 
261 	if (strlcpy(sock->conf.srv_name, srv->name,
262 	    sizeof(sock->conf.srv_name)) >= sizeof(sock->conf.srv_name)) {
263 		free(sock->conf.al);
264 		free(sock);
265 		fatalx("%s: strlcpy", __func__);
266 	}
267 
268 	TAILQ_FOREACH(a, srv->al, entry) {
269 		if ((acp = calloc(1, sizeof(*acp))) == NULL) {
270 			free(sock->conf.al);
271 			free(sock);
272 			fatal("%s: calloc", __func__);
273 		}
274 		memcpy(&acp->ss, &a->ss, sizeof(acp->ss));
275 		acp->ipproto = a->ipproto;
276 		acp->prefixlen = a->prefixlen;
277 		acp->port = a->port;
278 		if (strlen(a->ifname) != 0) {
279 			if (strlcpy(acp->ifname, a->ifname,
280 			    sizeof(acp->ifname)) >= sizeof(acp->ifname)) {
281 				fatalx("%s: interface name truncated",
282 				    __func__);
283 			}
284 		}
285 
286 		TAILQ_INSERT_TAIL(sock->conf.al, acp, entry);
287 	}
288 done:
289 	return (sock);
290 }
291 
292 void
293 sockets_launch(void)
294 {
295 	struct socket *sock;
296 
297 	TAILQ_FOREACH(sock, gotwebd_env->sockets, entry) {
298 		log_debug("%s: configuring socket %d (%d)", __func__,
299 		    sock->conf.id, sock->fd);
300 
301 		event_set(&sock->ev, sock->fd, EV_READ | EV_PERSIST,
302 		    sockets_socket_accept, sock);
303 
304 		if (event_add(&sock->ev, NULL))
305 			fatalx("event add sock");
306 
307 		evtimer_set(&sock->pause, sockets_accept_paused, sock);
308 
309 		log_debug("%s: running socket listener %d", __func__,
310 		    sock->conf.id);
311 	}
312 }
313 
314 void
315 sockets_purge(struct gotwebd *env)
316 {
317 	struct socket *sock, *tsock;
318 
319 	/* shutdown and remove sockets */
320 	TAILQ_FOREACH_SAFE(sock, env->sockets, entry, tsock) {
321 		if (event_initialized(&sock->ev))
322 			event_del(&sock->ev);
323 		if (evtimer_initialized(&sock->evt))
324 			evtimer_del(&sock->evt);
325 		if (evtimer_initialized(&sock->pause))
326 			evtimer_del(&sock->pause);
327 		if (sock->fd != -1)
328 			close(sock->fd);
329 		TAILQ_REMOVE(env->sockets, sock, entry);
330 	}
331 }
332 
333 int
334 sockets_dispatch_gotwebd(int fd, struct privsep_proc *p, struct imsg *imsg)
335 {
336 	struct privsep *ps = p->p_ps;
337 	int res = 0, cmd = 0, verbose;
338 
339 	switch (imsg->hdr.type) {
340 	case IMSG_CFG_SRV:
341 		config_getserver(gotwebd_env, imsg);
342 		break;
343 	case IMSG_CFG_SOCK:
344 		config_getsock(gotwebd_env, imsg);
345 		break;
346 	case IMSG_CFG_FD:
347 		config_getfd(gotwebd_env, imsg);
348 		break;
349 	case IMSG_CFG_DONE:
350 		config_getcfg(gotwebd_env, imsg);
351 		break;
352 	case IMSG_CTL_START:
353 		sockets_launch();
354 		break;
355 	case IMSG_CTL_VERBOSE:
356 		IMSG_SIZE_CHECK(imsg, &verbose);
357 		memcpy(&verbose, imsg->data, sizeof(verbose));
358 		log_setverbose(verbose);
359 		break;
360 	default:
361 		return -1;
362 	}
363 
364 	switch (cmd) {
365 	case 0:
366 		break;
367 	default:
368 		if (proc_compose_imsg(ps, PROC_GOTWEBD, -1, cmd,
369 		    imsg->hdr.peerid, -1, &res, sizeof(res)) == -1)
370 			return -1;
371 		break;
372 	}
373 
374 	return 0;
375 }
376 
377 void
378 sockets_sighdlr(int sig, short event, void *arg)
379 {
380 	switch (sig) {
381 	case SIGHUP:
382 		log_info("%s: ignoring SIGHUP", __func__);
383 		break;
384 	case SIGPIPE:
385 		log_info("%s: ignoring SIGPIPE", __func__);
386 		break;
387 	case SIGUSR1:
388 		log_info("%s: ignoring SIGUSR1", __func__);
389 		break;
390 	case SIGCHLD:
391 		break;
392 	default:
393 		log_info("SIGNAL: %d", sig);
394 		fatalx("unexpected signal");
395 	}
396 }
397 
398 void
399 sockets_shutdown(void)
400 {
401 	struct server *srv, *tsrv;
402 	struct socket *sock, *tsock;
403 
404 	sockets_purge(gotwebd_env);
405 
406 	/* clean sockets */
407 	TAILQ_FOREACH_SAFE(sock, gotwebd_env->sockets, entry, tsock) {
408 		TAILQ_REMOVE(gotwebd_env->sockets, sock, entry);
409 		close(sock->fd);
410 		free(sock);
411 	}
412 
413 	/* clean servers */
414 	TAILQ_FOREACH_SAFE(srv, gotwebd_env->servers, entry, tsrv)
415 		free(srv);
416 
417 	free(gotwebd_env->sockets);
418 	free(gotwebd_env->servers);
419 	free(gotwebd_env);
420 }
421 
422 int
423 sockets_privinit(struct gotwebd *env, struct socket *sock)
424 {
425 	struct privsep *ps = env->gotwebd_ps;
426 
427 	if (sock->conf.type == UNIX) {
428 		log_debug("%s: initializing unix socket %s", __func__,
429 		    sock->conf.unix_socket_name);
430 		sock->fd = sockets_unix_socket_listen(ps, sock);
431 		if (sock->fd == -1) {
432 			log_warnx("%s: create unix socket failed", __func__);
433 			return -1;
434 		}
435 	}
436 
437 	if (sock->conf.type == FCGI) {
438 		log_debug("%s: initializing fcgi socket for %s", __func__,
439 		    sock->conf.name);
440 		sock->fd = sockets_create_socket(sock->conf.al,
441 		    sock->conf.fcgi_socket_port);
442 		if (sock->fd == -1) {
443 			log_warnx("%s: create unix socket failed", __func__);
444 			return -1;
445 		}
446 	}
447 
448 	return 0;
449 }
450 
451 int
452 sockets_unix_socket_listen(struct privsep *ps, struct socket *sock)
453 {
454 	struct gotwebd *env = ps->ps_env;
455 	struct sockaddr_un sun;
456 	struct socket *tsock;
457 	int u_fd = -1;
458 	mode_t old_umask, mode;
459 
460 	TAILQ_FOREACH(tsock, env->sockets, entry) {
461 		if (strcmp(tsock->conf.unix_socket_name,
462 		    sock->conf.unix_socket_name) == 0 &&
463 		    tsock->fd != -1)
464 			return (tsock->fd);
465 	}
466 
467 	u_fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK| SOCK_CLOEXEC, 0);
468 	if (u_fd == -1) {
469 		log_warn("%s: socket", __func__);
470 		return -1;
471 	}
472 
473 	sun.sun_family = AF_UNIX;
474 	if (strlcpy(sun.sun_path, sock->conf.unix_socket_name,
475 	    sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
476 		log_warn("%s: %s name too long", __func__,
477 		    sock->conf.unix_socket_name);
478 		close(u_fd);
479 		return -1;
480 	}
481 
482 	if (unlink(sock->conf.unix_socket_name) == -1) {
483 		if (errno != ENOENT) {
484 			log_warn("%s: unlink %s", __func__,
485 			    sock->conf.unix_socket_name);
486 			close(u_fd);
487 			return -1;
488 		}
489 	}
490 
491 	old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
492 	mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP;
493 
494 	if (bind(u_fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
495 		log_warn("%s: bind: %s", __func__, sock->conf.unix_socket_name);
496 		close(u_fd);
497 		(void)umask(old_umask);
498 		return -1;
499 	}
500 
501 	(void)umask(old_umask);
502 
503 	if (chmod(sock->conf.unix_socket_name, mode) == -1) {
504 		log_warn("%s: chmod", __func__);
505 		close(u_fd);
506 		(void)unlink(sock->conf.unix_socket_name);
507 		return -1;
508 	}
509 
510 	if (chown(sock->conf.unix_socket_name, ps->ps_pw->pw_uid,
511 	    ps->ps_pw->pw_gid) == -1) {
512 		log_warn("%s: chown", __func__);
513 		close(u_fd);
514 		(void)unlink(sock->conf.unix_socket_name);
515 		return -1;
516 	}
517 
518 	if (listen(u_fd, SOCKS_BACKLOG) == -1) {
519 		log_warn("%s: listen", __func__);
520 		return -1;
521 	}
522 
523 	return u_fd;
524 }
525 
526 int
527 sockets_create_socket(struct addresslist *al, in_port_t port)
528 {
529 	struct addrinfo hints;
530 	struct address *a;
531 	int fd = -1, o_val = 1, flags;
532 
533 	memset(&hints, 0, sizeof(hints));
534 	hints.ai_family = AF_UNSPEC;
535 	hints.ai_socktype = SOCK_STREAM;
536 	hints.ai_flags |= AI_PASSIVE;
537 
538 	TAILQ_FOREACH(a, al, entry) {
539 		switch (a->ss.ss_family) {
540 		case AF_INET:
541 			((struct sockaddr_in *)(&a->ss))->sin_port = port;
542 			break;
543 		case AF_INET6:
544 			((struct sockaddr_in6 *)(&a->ss))->sin6_port = port;
545 			break;
546 		default:
547 			log_warnx("%s: unknown address family", __func__);
548 			goto fail;
549 		}
550 
551 		fd = socket(a->ss.ss_family, hints.ai_socktype,
552 		    a->ipproto);
553 			log_debug("%s: opening socket (%d) for %s", __func__,
554 			    fd, a->ifname);
555 
556 		if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &o_val,
557 		    sizeof(int)) == -1) {
558 			log_warn("%s: setsockopt error", __func__);
559 			return -1;
560 		}
561 
562 		/* non-blocking */
563 		flags = fcntl(fd, F_GETFL);
564 		flags |= O_NONBLOCK;
565 		fcntl(fd, F_SETFL, flags);
566 
567 		if (bind(fd, (struct sockaddr *)&a->ss, a->ss.ss_len) == -1) {
568 			close(fd);
569 			log_info("%s: can't bind to port %d", __func__,
570 			    ntohs(port));
571 			goto fail;
572 		}
573 
574 		if (listen(fd, SOMAXCONN) == -1) {
575 			log_warn("%s, unable to listen on socket", __func__);
576 			goto fail;
577 		}
578 	}
579 
580 	free(a);
581 	return (fd);
582 fail:
583 	free(a);
584 	return -1;
585 }
586 
587 int
588 sockets_accept_reserve(int sockfd, struct sockaddr *addr, socklen_t *addrlen,
589     int reserve, volatile int *counter)
590 {
591 	int ret;
592 
593 	if (getdtablecount() + reserve +
594 	    ((*counter + 1) * FD_NEEDED) >= getdtablesize()) {
595 		log_debug("inflight fds exceeded");
596 		errno = EMFILE;
597 		return -1;
598 	}
599 
600 	if ((ret = accept4(sockfd, addr, addrlen,
601 	    SOCK_NONBLOCK | SOCK_CLOEXEC)) > -1) {
602 		(*counter)++;
603 		log_debug("inflight incremented, now %d", *counter);
604 	}
605 
606 	return ret;
607 }
608 
609 void
610 sockets_accept_paused(int fd, short events, void *arg)
611 {
612 	struct socket *sock = (struct socket *)arg;
613 
614 	event_add(&sock->ev, NULL);
615 }
616 
617 void
618 sockets_socket_accept(int fd, short event, void *arg)
619 {
620 	struct socket *sock = (struct socket *)arg;
621 	struct sockaddr_storage ss;
622 	struct timeval backoff;
623 	struct request *c = NULL;
624 	socklen_t len;
625 	int s;
626 
627 	backoff.tv_sec = 1;
628 	backoff.tv_usec = 0;
629 
630 	event_add(&sock->ev, NULL);
631 	if (event & EV_TIMEOUT)
632 		return;
633 
634 	len = sizeof(ss);
635 
636 	s = sockets_accept_reserve(fd, (struct sockaddr *)&ss, &len,
637 	    FD_RESERVE, &cgi_inflight);
638 
639 	if (s == -1) {
640 		switch (errno) {
641 		case EINTR:
642 		case EWOULDBLOCK:
643 		case ECONNABORTED:
644 			return;
645 		case EMFILE:
646 		case ENFILE:
647 			event_del(&sock->ev);
648 			evtimer_add(&sock->pause, &backoff);
649 			return;
650 		default:
651 			log_warn("%s: accept", __func__);
652 		}
653 	}
654 
655 	if (client_cnt > GOTWEBD_MAXCLIENTS)
656 		goto err;
657 
658 	c = calloc(1, sizeof(struct request));
659 	if (c == NULL) {
660 		log_warn("%s", __func__);
661 		close(s);
662 		cgi_inflight--;
663 		return;
664 	}
665 
666 	c->fd = s;
667 	c->sock = sock;
668 	memcpy(c->priv_fd, sock->priv_fd, sizeof(c->priv_fd));
669 	c->buf_pos = 0;
670 	c->buf_len = 0;
671 	c->request_started = 0;
672 	c->sock->client_status = CLIENT_CONNECT;
673 
674 	event_set(&c->ev, s, EV_READ, fcgi_request, c);
675 	event_add(&c->ev, NULL);
676 
677 	evtimer_set(&c->tmo, fcgi_timeout, c);
678 	evtimer_add(&c->tmo, &timeout);
679 
680 	client_cnt++;
681 
682 	return;
683 err:
684 	cgi_inflight--;
685 	close(s);
686 	if (c != NULL)
687 		free(c);
688 }
689 
690 void
691 sockets_rlimit(int maxfd)
692 {
693 	struct rlimit rl;
694 
695 	if (getrlimit(RLIMIT_NOFILE, &rl) == -1)
696 		fatal("%s: failed to get resource limit", __func__);
697 	log_debug("%s: max open files %llu", __func__,
698 	    (unsigned long long)rl.rlim_max);
699 
700 	/*
701 	 * Allow the maximum number of open file descriptors for this
702 	 * login class (which should be the class "daemon" by default).
703 	 */
704 	if (maxfd == -1)
705 		rl.rlim_cur = rl.rlim_max;
706 	else
707 		rl.rlim_cur = MAXIMUM(rl.rlim_max, (rlim_t)maxfd);
708 	if (setrlimit(RLIMIT_NOFILE, &rl) == -1)
709 		fatal("%s: failed to set resource limit", __func__);
710 }