1 /*
2  * Copyright (c) 2016, 2019, 2020-2021 Tracey Emery <tracey@traceyemery.net>
3  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/param.h>
19 #include <sys/queue.h>
20 #include <sys/socket.h>
21 #include <sys/wait.h>
22 
23 #include <net/if.h>
24 #include <netinet/in.h>
25 
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <termios.h>
30 #include <err.h>
31 #include <errno.h>
32 #include <event.h>
33 #include <fcntl.h>
34 #include <imsg.h>
35 #include <pwd.h>
36 #include <signal.h>
37 #include <syslog.h>
38 #include <unistd.h>
39 #include <ctype.h>
40 #include <util.h>
41 
42 #include "got_opentemp.h"
43 #include "got_reference.h"
44 
45 #include "gotwebd.h"
46 
47 __dead void usage(void);
48 
49 int	 main(int, char **);
50 int	 gotwebd_configure(struct gotwebd *);
51 void	 gotwebd_configure_done(struct gotwebd *);
52 void	 gotwebd_sighdlr(int sig, short event, void *arg);
53 void	 gotwebd_shutdown(void);
54 void	 gotwebd_dispatch_sockets(int, short, void *);
55 
56 struct gotwebd	*gotwebd_env;
57 
58 void
59 imsg_event_add(struct imsgev *iev)
60 {
61 	if (iev->handler == NULL) {
62 		imsg_flush(&iev->ibuf);
63 		return;
64 	}
65 
66 	iev->events = EV_READ;
67 	if (iev->ibuf.w.queued)
68 		iev->events |= EV_WRITE;
69 
70 	event_del(&iev->ev);
71 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
72 	event_add(&iev->ev, NULL);
73 }
74 
75 int
76 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
77     pid_t pid, int fd, const void *data, uint16_t datalen)
78 {
79 	int ret;
80 
81 	ret = imsg_compose(&iev->ibuf, type, peerid, pid, fd, data, datalen);
82 	if (ret == -1)
83 		return (ret);
84 	imsg_event_add(iev);
85 	return (ret);
86 }
87 
88 int
89 main_compose_sockets(struct gotwebd *env, uint32_t type, int fd,
90     const void *data, uint16_t len)
91 {
92 	size_t	 i;
93 	int	 ret, d;
94 
95 	for (i = 0; i < env->nserver; ++i) {
96 		d = -1;
97 		if (fd != -1 && (d = dup(fd)) == -1)
98 			return (-1);
99 
100 		ret = imsg_compose_event(&env->iev_server[i], type, 0, -1,
101 		    d, data, len);
102 		if (ret == -1)
103 			return (-1);
104 
105 		/* prevent fd exhaustion */
106 		if (d != -1) {
107 			do {
108 				ret = imsg_flush(&env->iev_server[i].ibuf);
109 			} while (ret == -1 && errno == EAGAIN);
110 			if (ret == -1)
111 				return (-1);
112 			imsg_event_add(&env->iev_server[i]);
113 		}
114 	}
115 
116 	if (fd != -1)
117 		close(fd);
118 
119 	return 0;
120 }
121 
122 int
123 sockets_compose_main(struct gotwebd *env, uint32_t type, const void *d,
124     uint16_t len)
125 {
126 	return (imsg_compose_event(env->iev_parent, type, 0, -1, -1, d, len));
127 }
128 
129 void
130 gotwebd_dispatch_sockets(int fd, short event, void *arg)
131 {
132 	struct imsgev		*iev = arg;
133 	struct imsgbuf		*ibuf;
134 	struct imsg		 imsg;
135 	struct gotwebd		*env = gotwebd_env;
136 	ssize_t			 n;
137 	int			 shut = 0;
138 
139 	ibuf = &iev->ibuf;
140 
141 	if (event & EV_READ) {
142 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
143 			fatal("imsg_read error");
144 		if (n == 0)	/* Connection closed */
145 			shut = 1;
146 	}
147 	if (event & EV_WRITE) {
148 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
149 			fatal("msgbuf_write");
150 		if (n == 0)	/* Connection closed */
151 			shut = 1;
152 	}
153 
154 	for (;;) {
155 		if ((n = imsg_get(ibuf, &imsg)) == -1)
156 			fatal("imsg_get");
157 		if (n == 0)	/* No more messages. */
158 			break;
159 
160 		switch (imsg.hdr.type) {
161 		case IMSG_CFG_DONE:
162 			gotwebd_configure_done(env);
163 			break;
164 		default:
165 			fatalx("%s: unknown imsg type %d", __func__,
166 			    imsg.hdr.type);
167 		}
168 
169 		imsg_free(&imsg);
170 	}
171 
172 	if (!shut)
173 		imsg_event_add(iev);
174 	else {
175 		/* This pipe is dead.  Remove its event handler */
176 		event_del(&iev->ev);
177 		event_loopexit(NULL);
178 	}
179 }
180 
181 void
182 gotwebd_sighdlr(int sig, short event, void *arg)
183 {
184 	/* struct privsep	*ps = arg; */
185 
186 	switch (sig) {
187 	case SIGHUP:
188 		log_info("%s: ignoring SIGHUP", __func__);
189 		break;
190 	case SIGPIPE:
191 		log_info("%s: ignoring SIGPIPE", __func__);
192 		break;
193 	case SIGUSR1:
194 		log_info("%s: ignoring SIGUSR1", __func__);
195 		break;
196 	case SIGTERM:
197 	case SIGINT:
198 		gotwebd_shutdown();
199 		break;
200 	default:
201 		fatalx("unexpected signal");
202 	}
203 }
204 
205 static int
206 spawn_socket_process(struct gotwebd *env, const char *argv0, int n)
207 {
208 	const char	*argv[5];
209 	int		 argc = 0;
210 	int		 p[2];
211 	pid_t		 pid;
212 
213 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, p) == -1)
214 		fatal("socketpair");
215 
216 	switch (pid = fork()) {
217 	case -1:
218 		fatal("fork");
219 	case 0:		/* child */
220 		break;
221 	default:	/* parent */
222 		close(p[0]);
223 		imsg_init(&env->iev_server[n].ibuf, p[1]);
224 		env->iev_server[n].handler = gotwebd_dispatch_sockets;
225 		env->iev_server[n].data = &env->iev_server[n];
226 		event_set(&env->iev_server[n].ev, p[1], EV_READ,
227 		    gotwebd_dispatch_sockets, &env->iev_server[n]);
228 		event_add(&env->iev_server[n].ev, NULL);
229 		return 0;
230 	}
231 
232 	close(p[1]);
233 
234 	argv[argc++] = argv0;
235 	argv[argc++] = "-S";
236 	if (env->gotwebd_debug)
237 		argv[argc++] = "-d";
238 	if (env->gotwebd_verbose)
239 		argv[argc++] = "-v";
240 	argv[argc] = NULL;
241 
242 	if (p[0] != 3) {
243 		if (dup2(p[0], 3) == -1)
244 			fatal("dup2");
245 	} else if (fcntl(p[0], F_SETFD, 0) == -1)
246 		fatal("fcntl");
247 
248 	/* obnoxious cast */
249 	execvp(argv0, (char * const *)argv);
250 	fatal("execvp %s", argv0);
251 }
252 
253 __dead void
254 usage(void)
255 {
256 	fprintf(stderr, "usage: %s [-dnv] [-D macro=value] [-f file]\n",
257 	    getprogname());
258 	exit(1);
259 }
260 
261 int
262 main(int argc, char **argv)
263 {
264 	struct event		 sigint, sigterm, sighup, sigpipe, sigusr1;
265 	struct gotwebd		*env;
266 	struct passwd		*pw;
267 	int			 ch, i;
268 	int			 no_action = 0;
269 	int			 server_proc = 0;
270 	const char		*conffile = GOTWEBD_CONF;
271 	const char		*argv0;
272 
273 	if ((argv0 = argv[0]) == NULL)
274 		argv0 = "gotwebd";
275 
276 	env = calloc(1, sizeof(*env));
277 	if (env == NULL)
278 		fatal("%s: calloc", __func__);
279 	config_init(env);
280 
281 	/* log to stderr until daemonized */
282 	log_init(1, LOG_DAEMON);
283 
284 	while ((ch = getopt(argc, argv, "D:df:nSv")) != -1) {
285 		switch (ch) {
286 		case 'D':
287 			if (cmdline_symset(optarg) < 0)
288 				log_warnx("could not parse macro definition %s",
289 				    optarg);
290 			break;
291 		case 'd':
292 			env->gotwebd_debug = 1;
293 			break;
294 		case 'f':
295 			conffile = optarg;
296 			break;
297 		case 'n':
298 			no_action = 1;
299 			break;
300 		case 'S':
301 			server_proc = 1;
302 			break;
303 		case 'v':
304 			env->gotwebd_verbose++;
305 			break;
306 		default:
307 			usage();
308 		}
309 	}
310 
311 	argc -= optind;
312 	if (argc > 0)
313 		usage();
314 
315 	gotwebd_env = env;
316 	env->gotwebd_conffile = conffile;
317 
318 	if (parse_config(env->gotwebd_conffile, env) == -1)
319 		exit(1);
320 
321 	if (no_action) {
322 		fprintf(stderr, "configuration OK\n");
323 		exit(0);
324 	}
325 
326 	/* check for root privileges */
327 	if (geteuid())
328 		fatalx("need root privileges");
329 
330 	pw = getpwnam(GOTWEBD_USER);
331 	if (pw == NULL)
332 		fatalx("unknown user %s", GOTWEBD_USER);
333 	env->pw = pw;
334 
335 	log_init(env->gotwebd_debug, LOG_DAEMON);
336 	log_setverbose(env->gotwebd_verbose);
337 
338 	if (server_proc) {
339 		setproctitle("sockets");
340 		log_procinit("sockets");
341 
342 		if (chroot(pw->pw_dir) == -1)
343 			fatal("chroot %s", pw->pw_dir);
344 		if (chdir("/") == -1)
345 			fatal("chdir /");
346 		if (setgroups(1, &pw->pw_gid) == -1 ||
347 		    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1 ||
348 		    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
349 			fatal("failed to drop privileges");
350 
351 		sockets(env, 3);
352 		return 1;
353 	}
354 
355 	if (!env->gotwebd_debug && daemon(0, 0) == -1)
356 		fatal("daemon");
357 
358 	event_init();
359 
360 	env->nserver = env->prefork_gotwebd;
361 	env->iev_server = calloc(env->nserver, sizeof(*env->iev_server));
362 	if (env->iev_server == NULL)
363 		fatal("calloc");
364 
365 	for (i = 0; i < env->nserver; ++i) {
366 		if (spawn_socket_process(env, argv0, i) == -1)
367 			fatal("spawn_socket_process");
368 	}
369 
370 	log_procinit("gotwebd");
371 
372 	log_info("%s startup", getprogname());
373 
374 	signal_set(&sigint, SIGINT, gotwebd_sighdlr, env);
375 	signal_set(&sigterm, SIGTERM, gotwebd_sighdlr, env);
376 	signal_set(&sighup, SIGHUP, gotwebd_sighdlr, env);
377 	signal_set(&sigpipe, SIGPIPE, gotwebd_sighdlr, env);
378 	signal_set(&sigusr1, SIGUSR1, gotwebd_sighdlr, env);
379 
380 	signal_add(&sigint, NULL);
381 	signal_add(&sigterm, NULL);
382 	signal_add(&sighup, NULL);
383 	signal_add(&sigpipe, NULL);
384 	signal_add(&sigusr1, NULL);
385 
386 	if (gotwebd_configure(env) == -1)
387 		fatalx("configuration failed");
388 
389 #ifdef PROFILE
390 	if (unveil("gmon.out", "rwc") != 0)
391 		err(1, "gmon.out");
392 #endif
393 
394 	if (unveil(env->httpd_chroot, "r") == -1)
395 		err(1, "unveil");
396 
397 	if (unveil(GOTWEBD_CONF, "r") == -1)
398 		err(1, "unveil");
399 
400 	if (unveil(NULL, NULL) != 0)
401 		err(1, "unveil");
402 
403 #ifndef PROFILE
404 	if (pledge("stdio", NULL) == -1)
405 		err(1, "pledge");
406 #endif
407 
408 	event_dispatch();
409 
410 	log_debug("%s gotwebd exiting", getprogname());
411 
412 	return (0);
413 }
414 
415 int
416 gotwebd_configure(struct gotwebd *env)
417 {
418 	struct server *srv;
419 	struct socket *sock;
420 
421 	/* gotweb need to reload its config. */
422 	env->gotwebd_reload = env->prefork_gotwebd;
423 
424 	/* send our gotweb servers */
425 	TAILQ_FOREACH(srv, &env->servers, entry) {
426 		if (config_setserver(env, srv) == -1)
427 			fatalx("%s: send server error", __func__);
428 	}
429 
430 	/* send our sockets */
431 	TAILQ_FOREACH(sock, &env->sockets, entry) {
432 		if (config_setsock(env, sock) == -1)
433 			fatalx("%s: send socket error", __func__);
434 		if (config_setfd(env, sock) == -1)
435 			fatalx("%s: send priv_fd error", __func__);
436 	}
437 
438 	if (main_compose_sockets(env, IMSG_CFG_DONE, -1, NULL, 0) == -1)
439 		fatal("main_compose_sockets IMSG_CFG_DONE");
440 
441 	return (0);
442 }
443 
444 void
445 gotwebd_configure_done(struct gotwebd *env)
446 {
447 	if (env->gotwebd_reload == 0) {
448 		log_warnx("%s: configuration already finished", __func__);
449 		return;
450 	}
451 
452 	env->gotwebd_reload--;
453 	if (env->gotwebd_reload == 0 &&
454 	    main_compose_sockets(env, IMSG_CTL_START, -1, NULL, 0) == -1)
455 		fatal("main_compose_sockets IMSG_CTL_START");
456 }
457 
458 void
459 gotwebd_shutdown(void)
460 {
461 	struct gotwebd	*env = gotwebd_env;
462 	pid_t		 pid;
463 	int		 i, status;
464 
465 	for (i = 0; i < env->nserver; ++i) {
466 		event_del(&env->iev_server[i].ev);
467 		imsg_clear(&env->iev_server[i].ibuf);
468 		close(env->iev_server[i].ibuf.fd);
469 		env->iev_server[i].ibuf.fd = -1;
470 	}
471 
472 	do {
473 		pid = waitpid(WAIT_ANY, &status, 0);
474 		if (pid <= 0)
475 			continue;
476 
477 		if (WIFSIGNALED(status))
478 			log_warnx("lost child: pid %u terminated; signal %d",
479 			    pid, WTERMSIG(status));
480 		else if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
481 			log_warnx("lost child: pid %u exited abnormally",
482 			    pid);
483 	} while (pid != -1 || (pid == -1 && errno == EINTR));
484 
485 	free(gotwebd_env);
486 
487 	log_warnx("gotwebd terminating");
488 	exit(0);
489 }