1 /*
2  * Copyright (c) 2020, 2021, 2022, 2023 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "gmid.h"
18 
19 #include <sys/stat.h>
20 
21 #include <errno.h>
22 #include <fcntl.h>
23 #include <getopt.h>
24 #include <locale.h>
25 #include <libgen.h>
26 #include <limits.h>
27 #include <grp.h>
28 #include <pwd.h>
29 #include <signal.h>
30 #include <string.h>
31 #include <syslog.h>
32 #include <vis.h>
33 
34 #include "log.h"
35 #include "proc.h"
36 
37 #ifndef nitems
38 #define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
39 #endif
40 
41 static int main_configure(struct conf *);
42 static void main_configure_done(struct conf *);
43 static void main_reload(struct conf *);
44 static void main_sig_handler(int, short, void *);
45 static int main_dispatch_server(int, struct privsep_proc *, struct imsg *);
46 static int main_dispatch_crypto(int, struct privsep_proc *, struct imsg *);
47 static int main_dispatch_logger(int, struct privsep_proc *, struct imsg *);
48 static void __dead main_shutdown(struct conf *);
49 static void main_print_conf(struct conf *);
50 
51 static struct privsep_proc procs[] = {
52 	{ "server",	PROC_SERVER,	main_dispatch_server, server },
53 	{ "crypto",	PROC_CRYPTO,	main_dispatch_crypto, crypto },
54 	{ "logger",	PROC_LOGGER,	main_dispatch_logger, logger },
55 };
56 
57 static const char	*opts = "c:D:fI:hnP:T:U:VvX:";
58 
59 static const struct option longopts[] = {
60 	{"help",	no_argument,		NULL,	'h'},
61 	{"version",	no_argument,		NULL,	'V'},
62 	{NULL,		0,			NULL,	0},
63 };
64 
65 int sock4, sock6;
66 int privsep_process;
67 int pidfd = -1;
68 
69 int debug, verbose;
70 
71 const char *config_path = SYSCONFDIR "/gmid.conf";
72 const char *pidfile;
73 
74 static void
75 usage(void)
76 {
77 	fprintf(stderr,
78 	    "Version: " GMID_STRING "\n"
79 	    "Usage: %s [-fnv] [-c config] [-D macro=value] [-P pidfile]\n",
80 	    getprogname());
81 }
82 
83 /*
84  * Used by the server process, defined here so gemexp can provide
85  * its own implementation.
86  */
87 void
88 log_request(struct client *c, int code, const char *meta)
89 {
90 	struct conf *conf = c->conf;
91 	char tstamp[64], rfc3339[32];
92 	char cntmp[64], cn[64] = "-";
93 	char b[GEMINI_URL_LEN];
94 	char *fmted;
95 	const char *t;
96 	struct tm *tm;
97 	time_t now;
98 	int ec;
99 
100 	if ((now = time(NULL)) == -1)
101 		fatal("time");
102 	if ((tm = localtime(&now)) == NULL)
103 		fatal("localtime");
104 	if (strftime(tstamp, sizeof(tstamp), "%d/%b%Y:%H:%M:%S %z", tm) == 0)
105 		fatal("strftime");
106 	if (strftime(rfc3339, sizeof(rfc3339), "%FT%T%z", tm) == 0)
107 		fatal("strftime");
108 
109 	if (c->iri.schema != NULL) {
110 		/* serialize the IRI */
111 		strlcpy(b, c->iri.schema, sizeof(b));
112 		strlcat(b, "://", sizeof(b));
113 
114 		/* log the decoded host name, but if it was invalid
115 		 * use the raw one. */
116 		if (*c->domain != '\0')
117 			strlcat(b, c->domain, sizeof(b));
118 		else
119 			strlcat(b, c->iri.host, sizeof(b));
120 
121 		if (*c->iri.path != '/')
122 			strlcat(b, "/", sizeof(b));
123 		strlcat(b, c->iri.path, sizeof(b)); /* TODO: sanitize UTF8 */
124 		if (*c->iri.query != '\0') {	    /* TODO: sanitize UTF8 */
125 			strlcat(b, "?", sizeof(b));
126 			strlcat(b, c->iri.query, sizeof(b));
127 		}
128 	} else {
129 		if ((t = c->req) == NULL)
130 			t = "";
131 		strlcpy(b, t, sizeof(b));
132 	}
133 
134 	if (tls_peer_cert_provided(c->ctx)) {
135 		const char *subj;
136 		char *n;
137 
138 		subj = tls_peer_cert_subject(c->ctx);
139 		if ((n = strstr(subj, "/CN=")) != NULL) {
140 			strlcpy(cntmp, subj + 4, sizeof(cntmp));
141 			if ((n = strchr(cntmp, '/')) != NULL)
142 				*n = '\0';
143 			strnvis(cn, cntmp, sizeof(cn), VIS_WHITE|VIS_DQ);
144 		}
145 	}
146 
147 	switch (conf->log_format) {
148 	case LOG_FORMAT_LEGACY:
149 		ec = asprintf(&fmted, "%s:%s GET %s %d %s", c->rhost,
150 		    c->rserv, b, code, meta);
151 		break;
152 
153 	case LOG_FORMAT_CONDENSED:
154 		/*
155 		 * XXX it should log the size of the request and
156 		 * response.
157 		 */
158 		ec = asprintf(&fmted, "%s %s %s %s %s 0 0 %d %s", rfc3339,
159 		    c->rhost, cn, *c->domain == '\0' ? c->iri.host : c->domain,
160 		    b, code, meta);
161 		break;
162 
163 	/*
164 	 * Attempt to be compatible with the default Apache httpd'
165 	 * LogFormat "%h %l %u %t \"%r\" %>s %b"
166 	 * see <https://httpd.apache.org/docs/current/mod/mod_log_config.html>
167 	 */
168 	case LOG_FORMAT_COMMON:
169 		/*
170 		 * XXX it should log the size of the response.
171 		 */
172 		ec = asprintf(&fmted, "%s %s - %s %s \"%s\" %d 0",
173 		    *c->domain == '\0' ? c->iri.host : c->domain,
174 		    c->rhost, cn, tstamp, b, code);
175 		break;
176 
177 	/*
178 	 * Attempt to be compatible with the default nginx' log_format
179 	 * combined:
180 	 * '$remote_addr - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent"';
181 	 */
182 	case LOG_FORMAT_COMBINED:
183 	default:
184 		/*
185 		 * XXX it should log the size of the response.
186 		 */
187 		ec = asprintf(&fmted, "%s - %s [%s] \"%s\" %d 0 \"-\" \"\"",
188 		    c->rhost, cn, tstamp, b, code);
189 		break;
190 	}
191 
192 	if (ec == -1)
193 		fatal("asprintf");
194 
195 	if (debug)
196 		fprintf(stderr, "%s\n", fmted);
197 
198 	proc_compose(conf->ps, PROC_LOGGER, IMSG_LOG_REQUEST,
199 	    fmted, ec + 1);
200 
201 	free(fmted);
202 }
203 
204 static int
205 write_pidfile(const char *pidfile)
206 {
207 	struct flock	lock;
208 	int		fd;
209 
210 	if (pidfile == NULL)
211 		return -1;
212 
213 	if ((fd = open(pidfile, O_WRONLY|O_CREAT|O_CLOEXEC, 0600)) == -1)
214 		fatal("can't open pidfile %s", pidfile);
215 
216 	lock.l_start = 0;
217 	lock.l_len = 0;
218 	lock.l_type = F_WRLCK;
219 	lock.l_whence = SEEK_SET;
220 
221 	if (fcntl(fd, F_SETLK, &lock) == -1)
222 		fatalx("can't lock %s, gmid is already running?", pidfile);
223 
224 	if (ftruncate(fd, 0) == -1)
225 		fatal("ftruncate %s", pidfile);
226 
227 	dprintf(fd, "%d\n", getpid());
228 
229 	return fd;
230 }
231 
232 int
233 main(int argc, char **argv)
234 {
235 	struct conf *conf;
236 	struct privsep *ps;
237 	const char *errstr, *title = NULL;
238 	const char *user = NULL, *chroot = NULL;
239 	size_t i;
240 	int ch, conftest = 0;
241 	int proc_instance = 0;
242 	int proc_id = PROC_PARENT;
243 	int argc0 = argc;
244 
245 	setlocale(LC_CTYPE, "");
246 
247 	/* log to stderr until daemonized */
248 	log_init(1, LOG_DAEMON);
249 
250 	while ((ch = getopt_long(argc, argv, opts, longopts, NULL)) != -1) {
251 		switch (ch) {
252 		case 'c':
253 			config_path = absolutify_path(optarg);
254 			break;
255 		case 'D':
256 			if (cmdline_symset(optarg) == -1)
257 				fatalx("could not parse macro definition: %s",
258 				    optarg);
259 			break;
260 		case 'f':
261 			debug = 1;
262 			break;
263 		case 'h':
264 			usage();
265 			return 0;
266 		case 'I':
267 			proc_instance = strtonum(optarg, 0, PROC_MAX_INSTANCES,
268 			    &errstr);
269 			if (errstr != NULL)
270 				fatalx("invalid process instance");
271 			break;
272 		case 'n':
273 			conftest++;
274 			break;
275 		case 'P':
276 			pidfile = absolutify_path(optarg);
277 			break;
278 		case 'T':
279 			title = optarg;
280 			proc_id = proc_getid(procs, nitems(procs), title);
281 			if (proc_id == PROC_MAX)
282 				fatalx("invalid process name");
283 			break;
284 		case 'U':
285 			user = optarg;
286 			break;
287 		case 'V':
288 			puts("Version: " GMID_STRING);
289 			return 0;
290 		case 'v':
291 			verbose = 1;
292 			break;
293 		case 'X':
294 			chroot = optarg;
295 			break;
296 		default:
297 			usage();
298 			return 1;
299 		}
300 	}
301 
302 	if (argc - optind != 0)
303 		usage();
304 
305 	conf = config_new();
306 
307 	/*
308 	 * Only the parent loads the config, the others get user and
309 	 * chroot via flags and the rest via imsg.
310 	 */
311 	if (proc_id == PROC_PARENT) {
312 		if (parse_conf(conf, config_path) == -1)
313 			fatalx("failed to load configuration file");
314 		if (*conf->chroot != '\0' && *conf->user == '\0')
315 			fatalx("can't chroot without a user to switch to.");
316 	} else {
317 		if (user)
318 			strlcpy(conf->user, user, sizeof(conf->user));
319 		if (chroot)
320 			strlcpy(conf->chroot, chroot, sizeof(conf->chroot));
321 	}
322 
323 	if ((ps = calloc(1, sizeof(*ps))) == NULL)
324 		fatal("calloc");
325 	ps->ps_env = conf;
326 	conf->ps = ps;
327 	if (*conf->user) {
328 		if (geteuid())
329 			fatalx("need root privileges");
330 		if ((ps->ps_pw = getpwnam(conf->user)) == NULL)
331 			fatalx("unknown user %s", conf->user);
332 		if (*conf->chroot == '\0')
333 			strlcpy(conf->chroot, ps->ps_pw->pw_dir,
334 			    sizeof(conf->chroot));
335 	}
336 
337 	if (conftest) {
338 		conf->conftest = 1;
339 		if (config_test(conf) == -1)
340 			fatalx("failed to load the configuration");
341 		fprintf(stderr, "config OK\n");
342 		if (conftest > 1)
343 			main_print_conf(conf);
344 		return 0;
345 	}
346 
347 	ps->ps_instances[PROC_SERVER] = conf->prefork;
348 	ps->ps_instance = proc_instance;
349 	if (title != NULL)
350 		ps->ps_title[proc_id] = title;
351 
352 	if (*conf->chroot != '\0') {
353 		for (i = 0; i < nitems(procs); ++i)
354 			procs[i].p_chroot = conf->chroot;
355 	}
356 
357 	log_init(debug, LOG_DAEMON);
358 	log_setverbose(verbose);
359 	if (title != NULL)
360 		log_procinit(title);
361 
362 	/* only the parent returns */
363 	proc_init(ps, procs, nitems(procs), debug, argc0, argv, proc_id);
364 
365 	log_procinit("main");
366 	if (!debug && daemon(0, 0) == -1)
367 		fatal("daemon");
368 
369 	pidfd = write_pidfile(pidfile);
370 
371 	sandbox_main_process();
372 
373 	event_init();
374 
375 	signal(SIGPIPE, SIG_IGN);
376 
377 	signal_set(&ps->ps_evsigint, SIGINT, main_sig_handler, ps);
378 	signal_set(&ps->ps_evsigterm, SIGTERM, main_sig_handler, ps);
379 	signal_set(&ps->ps_evsigchld, SIGCHLD, main_sig_handler, ps);
380 	signal_set(&ps->ps_evsighup, SIGHUP, main_sig_handler, ps);
381 	signal_set(&ps->ps_evsigusr1, SIGUSR1, main_sig_handler, ps);
382 
383 	signal_add(&ps->ps_evsigint, NULL);
384 	signal_add(&ps->ps_evsigterm, NULL);
385 	signal_add(&ps->ps_evsigchld, NULL);
386 	signal_add(&ps->ps_evsighup, NULL);
387 	signal_add(&ps->ps_evsigusr1, NULL);
388 
389 	proc_connect(ps);
390 
391 	if (main_configure(conf) == -1)
392 		fatal("configuration failed");
393 
394 	event_dispatch();
395 	main_shutdown(conf);
396 	/* NOTREACHED */
397 	return 0;
398 }
399 
400 static int
401 main_send_logfd(struct conf *conf)
402 {
403 	struct privsep	*ps = conf->ps;
404 	char		 path[PATH_MAX];
405 	int		 r, fd = -1;
406 
407 	if (conf->log_access) {
408 		r = snprintf(path, sizeof(path), "%s%s%s", conf->chroot,
409 		    *conf->chroot == '\0' ? "" : "/", conf->log_access);
410 		if (r < 0 || (size_t)r >= sizeof(path)) {
411 			log_warnx("path too long: %s", conf->log_access);
412 			goto done;
413 		}
414 
415 		fd = open(path, O_WRONLY|O_CREAT|O_APPEND, 0600);
416 		if (fd == -1)
417 			log_warn("can't open %s", conf->log_access);
418 	}
419 
420  done:
421 	if (proc_compose_imsg(ps, PROC_LOGGER, -1, IMSG_LOG_ACCESS, -1, fd,
422 	    NULL, 0) == -1)
423 		return -1;
424 	if (proc_compose_imsg(ps, PROC_LOGGER, -1, IMSG_LOG_FACILITY, -1, -1,
425 	    &conf->log_facility, sizeof(conf->log_facility)) == -1)
426 		return -1;
427 	if (proc_compose_imsg(ps, PROC_LOGGER, -1, IMSG_LOG_SYSLOG, -1, -1,
428 	    &conf->log_syslog, sizeof(conf->log_syslog)) == -1)
429 		return -1;
430 	return 0;
431 }
432 
433 static int
434 main_configure(struct conf *conf)
435 {
436 	struct privsep	*ps = conf->ps;
437 
438 	if (main_send_logfd(conf) == -1)
439 		return -1;
440 
441 	conf->reload = conf->prefork + 1; /* servers, crypto */
442 
443 	if (proc_compose(ps, PROC_SERVER, IMSG_RECONF_START, NULL, 0) == -1)
444 		return -1;
445 	if (proc_compose(ps, PROC_CRYPTO, IMSG_RECONF_START, NULL, 0) == -1)
446 		return -1;
447 
448 	if (config_send(conf) == -1)
449 		return -1;
450 
451 	if (proc_compose(ps, PROC_SERVER, IMSG_RECONF_END, NULL, 0) == -1)
452 		return -1;
453 	if (proc_compose(ps, PROC_CRYPTO, IMSG_RECONF_END, NULL, 0) == -1)
454 		return -1;
455 
456 	return 0;
457 }
458 
459 static void
460 main_configure_done(struct conf *conf)
461 {
462 	if (conf->reload == 0) {
463 		log_warnx("configuration already done");
464 		return;
465 	}
466 
467 	conf->reload--;
468 	/* send IMSG_CTL_START? */
469 }
470 
471 static void
472 main_reload(struct conf *conf)
473 {
474 	if (conf->reload) {
475 		log_debug("%s: already in progress: %d pending",
476 		    __func__, conf->reload);
477 		return;
478 	}
479 
480 	log_debug("%s: config file %s", __func__, config_path);
481 	config_purge(conf);
482 
483 	if (parse_conf(conf, config_path) == -1) {
484 		log_warnx("failed to parse the config");
485 		return;
486 	}
487 
488 	main_configure(conf);
489 }
490 
491 static void
492 main_sig_handler(int sig, short ev, void *arg)
493 {
494 	struct privsep	*ps = arg;
495 
496 	/*
497 	 * Normal signal handler rules don't apply here because libevent
498 	 * decouples for us.
499 	 */
500 
501 	switch (sig) {
502 	case SIGHUP:
503 		if (privsep_process != PROC_PARENT)
504 			return;
505 		log_info("reload requested with SIGHUP");
506 		main_reload(ps->ps_env);
507 		break;
508 	case SIGCHLD:
509 		log_warnx("one child died, quitting");
510 		/* fallthrough */
511 	case SIGTERM:
512 	case SIGINT:
513 		main_shutdown(ps->ps_env);
514 		break;
515 	case SIGUSR1:
516 		main_send_logfd(ps->ps_env);
517 		break;
518 	default:
519 		fatalx("unexpected signal %d", sig);
520 	}
521 }
522 
523 static int
524 main_dispatch_server(int fd, struct privsep_proc *p, struct imsg *imsg)
525 {
526 	struct privsep	*ps = p->p_ps;
527 	struct conf	*conf = ps->ps_env;
528 
529 	switch (imsg_get_type(imsg)) {
530 	case IMSG_RECONF_DONE:
531 		main_configure_done(conf);
532 		break;
533 	default:
534 		return -1;
535 	}
536 
537 	return 0;
538 }
539 
540 static int
541 main_dispatch_crypto(int fd, struct privsep_proc *p, struct imsg *imsg)
542 {
543 	struct privsep	*ps = p->p_ps;
544 	struct conf	*conf = ps->ps_env;
545 
546 	switch (imsg_get_type(imsg)) {
547 	case IMSG_RECONF_DONE:
548 		main_configure_done(conf);
549 		break;
550 	default:
551 		return -1;
552 	}
553 
554 	return 0;
555 }
556 
557 static int
558 main_dispatch_logger(int fd, struct privsep_proc *p, struct imsg *imsg)
559 {
560 	struct privsep	*ps = p->p_ps;
561 	struct conf	*conf = ps->ps_env;
562 
563 	switch (imsg_get_type(imsg)) {
564 	case IMSG_RECONF_DONE:
565 		main_configure_done(conf);
566 		break;
567 	default:
568 		return -1;
569 	}
570 
571 	return 0;
572 }
573 
574 static void __dead
575 main_shutdown(struct conf *conf)
576 {
577 	proc_kill(conf->ps);
578 	config_purge(conf);
579 	free(conf->ps);
580 	/* free(conf); */
581 
582 	log_info("parent terminating, pid %d", getpid());
583 
584 	if (pidfd != -1)
585 		close(pidfd);
586 
587 	exit(0);
588 }
589 
590 static void
591 main_print_conf(struct conf *conf)
592 {
593 	struct vhost	*h;
594 	/* struct location	*l; */
595 	/* struct envlist	*e; */
596 	/* struct alist	*a; */
597 
598 	if (*conf->chroot != '\0')
599 		printf("chroot \"%s\"\n", conf->chroot);
600 	/* XXX: defined mimes? */
601 	printf("prefork %d\n", conf->prefork);
602 	/* XXX: protocols? */
603 	if (*conf->user != '\0')
604 		printf("user \"%s\"\n", conf->user);
605 
606 	TAILQ_FOREACH(h, &conf->hosts, vhosts) {
607 		printf("\nserver \"%s\" {\n", h->domain);
608 		printf("	cert \"%s\"\n", h->cert);
609 		printf("	key \"%s\"\n", h->key);
610 		/* TODO: print locations... */
611 		printf("}\n");
612 	}
613 }