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 = "/etc/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 (conftest) {
324 		if (config_test(conf) == -1)
325 			fatalx("failed to load the configuration");
326 		fprintf(stderr, "config OK\n");
327 		if (conftest > 1)
328 			main_print_conf(conf);
329 		return 0;
330 	}
331 
332 	if ((ps = calloc(1, sizeof(*ps))) == NULL)
333 		fatal("calloc");
334 	ps->ps_env = conf;
335 	conf->ps = ps;
336 	if (*conf->user) {
337 		if (geteuid())
338 			fatalx("need root privileges");
339 		if ((ps->ps_pw = getpwnam(conf->user)) == NULL)
340 			fatalx("unknown user %s", conf->user);
341 		if (*conf->chroot == '\0')
342 			strlcpy(conf->chroot, ps->ps_pw->pw_dir,
343 			    sizeof(conf->chroot));
344 	}
345 
346 	ps->ps_instances[PROC_SERVER] = conf->prefork;
347 	ps->ps_instance = proc_instance;
348 	if (title != NULL)
349 		ps->ps_title[proc_id] = title;
350 
351 	if (*conf->chroot != '\0') {
352 		for (i = 0; i < nitems(procs); ++i)
353 			procs[i].p_chroot = conf->chroot;
354 	}
355 
356 	log_init(debug, LOG_DAEMON);
357 	log_setverbose(verbose);
358 	if (title != NULL)
359 		log_procinit(title);
360 
361 	/* only the parent returns */
362 	proc_init(ps, procs, nitems(procs), debug, argc0, argv, proc_id);
363 
364 	log_procinit("main");
365 	if (!debug && daemon(0, 0) == -1)
366 		fatal("daemon");
367 
368 	pidfd = write_pidfile(pidfile);
369 
370 	sandbox_main_process();
371 
372 	event_init();
373 
374 	signal(SIGPIPE, SIG_IGN);
375 
376 	signal_set(&ps->ps_evsigint, SIGINT, main_sig_handler, ps);
377 	signal_set(&ps->ps_evsigterm, SIGTERM, main_sig_handler, ps);
378 	signal_set(&ps->ps_evsigchld, SIGCHLD, main_sig_handler, ps);
379 	signal_set(&ps->ps_evsighup, SIGHUP, main_sig_handler, ps);
380 	signal_set(&ps->ps_evsigusr1, SIGUSR1, main_sig_handler, ps);
381 
382 	signal_add(&ps->ps_evsigint, NULL);
383 	signal_add(&ps->ps_evsigterm, NULL);
384 	signal_add(&ps->ps_evsigchld, NULL);
385 	signal_add(&ps->ps_evsighup, NULL);
386 	signal_add(&ps->ps_evsigusr1, NULL);
387 
388 	proc_connect(ps);
389 
390 	if (main_configure(conf) == -1)
391 		fatal("configuration failed");
392 
393 	event_dispatch();
394 	main_shutdown(conf);
395 	/* NOTREACHED */
396 	return 0;
397 }
398 
399 static int
400 main_send_logfd(struct conf *conf)
401 {
402 	struct privsep	*ps = conf->ps;
403 	char		 path[PATH_MAX];
404 	int		 r, fd = -1;
405 
406 	if (conf->log_access) {
407 		r = snprintf(path, sizeof(path), "%s%s%s", conf->chroot,
408 		    *conf->chroot == '\0' ? "" : "/", conf->log_access);
409 		if (r < 0 || (size_t)r >= sizeof(path)) {
410 			log_warnx("path too long: %s", conf->log_access);
411 			goto done;
412 		}
413 
414 		fd = open(conf->log_access, O_WRONLY|O_CREAT|O_APPEND, 0600);
415 		if (fd == -1)
416 			log_warn("can't open %s", conf->log_access);
417 	}
418 
419  done:
420 	if (proc_compose_imsg(ps, PROC_LOGGER, -1, IMSG_LOG_ACCESS, -1, fd,
421 	    NULL, 0) == -1)
422 		return -1;
423 	if (proc_compose_imsg(ps, PROC_LOGGER, -1, IMSG_LOG_FACILITY, -1, -1,
424 	    &conf->log_facility, sizeof(conf->log_facility)) == -1)
425 		return -1;
426 	if (proc_compose_imsg(ps, PROC_LOGGER, -1, IMSG_LOG_SYSLOG, -1, -1,
427 	    &conf->log_syslog, sizeof(conf->log_syslog)) == -1)
428 		return -1;
429 	return 0;
430 }
431 
432 static int
433 main_configure(struct conf *conf)
434 {
435 	struct privsep	*ps = conf->ps;
436 
437 	if (main_send_logfd(conf) == -1)
438 		return -1;
439 
440 	conf->reload = conf->prefork + 1; /* servers, crypto */
441 
442 	if (proc_compose(ps, PROC_SERVER, IMSG_RECONF_START, NULL, 0) == -1)
443 		return -1;
444 	if (proc_compose(ps, PROC_CRYPTO, IMSG_RECONF_START, NULL, 0) == -1)
445 		return -1;
446 
447 	if (config_send(conf) == -1)
448 		return -1;
449 
450 	if (proc_compose(ps, PROC_SERVER, IMSG_RECONF_END, NULL, 0) == -1)
451 		return -1;
452 	if (proc_compose(ps, PROC_CRYPTO, IMSG_RECONF_END, NULL, 0) == -1)
453 		return -1;
454 
455 	return 0;
456 }
457 
458 static void
459 main_configure_done(struct conf *conf)
460 {
461 	if (conf->reload == 0) {
462 		log_warnx("configuration already done");
463 		return;
464 	}
465 
466 	conf->reload--;
467 	/* send IMSG_CTL_START? */
468 }
469 
470 static void
471 main_reload(struct conf *conf)
472 {
473 	if (conf->reload) {
474 		log_debug("%s: already in progress: %d pending",
475 		    __func__, conf->reload);
476 		return;
477 	}
478 
479 	log_debug("%s: config file %s", __func__, config_path);
480 	config_purge(conf);
481 
482 	if (parse_conf(conf, config_path) == -1) {
483 		log_warnx("failed to parse the config");
484 		return;
485 	}
486 
487 	main_configure(conf);
488 }
489 
490 static void
491 main_sig_handler(int sig, short ev, void *arg)
492 {
493 	struct privsep	*ps = arg;
494 
495 	/*
496 	 * Normal signal handler rules don't apply here because libevent
497 	 * decouples for us.
498 	 */
499 
500 	switch (sig) {
501 	case SIGHUP:
502 		if (privsep_process != PROC_PARENT)
503 			return;
504 		log_info("reload requested with SIGHUP");
505 		main_reload(ps->ps_env);
506 		break;
507 	case SIGCHLD:
508 		log_warnx("one child died, quitting");
509 		/* fallthrough */
510 	case SIGTERM:
511 	case SIGINT:
512 		main_shutdown(ps->ps_env);
513 		break;
514 	case SIGUSR1:
515 		main_send_logfd(ps->ps_env);
516 		break;
517 	default:
518 		fatalx("unexpected signal %d", sig);
519 	}
520 }
521 
522 static int
523 main_dispatch_server(int fd, struct privsep_proc *p, struct imsg *imsg)
524 {
525 	struct privsep	*ps = p->p_ps;
526 	struct conf	*conf = ps->ps_env;
527 
528 	switch (imsg->hdr.type) {
529 	case IMSG_RECONF_DONE:
530 		main_configure_done(conf);
531 		break;
532 	default:
533 		return -1;
534 	}
535 
536 	return 0;
537 }
538 
539 static int
540 main_dispatch_crypto(int fd, struct privsep_proc *p, struct imsg *imsg)
541 {
542 	struct privsep	*ps = p->p_ps;
543 	struct conf	*conf = ps->ps_env;
544 
545 	switch (imsg->hdr.type) {
546 	case IMSG_RECONF_DONE:
547 		main_configure_done(conf);
548 		break;
549 	default:
550 		return -1;
551 	}
552 
553 	return 0;
554 }
555 
556 static int
557 main_dispatch_logger(int fd, struct privsep_proc *p, struct imsg *imsg)
558 {
559 	struct privsep	*ps = p->p_ps;
560 	struct conf	*conf = ps->ps_env;
561 
562 	switch (imsg->hdr.type) {
563 	case IMSG_RECONF_DONE:
564 		main_configure_done(conf);
565 		break;
566 	default:
567 		return -1;
568 	}
569 
570 	return 0;
571 }
572 
573 static void __dead
574 main_shutdown(struct conf *conf)
575 {
576 	proc_kill(conf->ps);
577 	config_purge(conf);
578 	free(conf->ps);
579 	/* free(conf); */
580 
581 	log_info("parent terminating, pid %d", getpid());
582 
583 	if (pidfd != -1)
584 		close(pidfd);
585 
586 	exit(0);
587 }
588 
589 static void
590 main_print_conf(struct conf *conf)
591 {
592 	struct vhost	*h;
593 	/* struct location	*l; */
594 	/* struct envlist	*e; */
595 	/* struct alist	*a; */
596 
597 	if (*conf->chroot != '\0')
598 		printf("chroot \"%s\"\n", conf->chroot);
599 	/* XXX: defined mimes? */
600 	printf("prefork %d\n", conf->prefork);
601 	/* XXX: protocols? */
602 	if (*conf->user != '\0')
603 		printf("user \"%s\"\n", conf->user);
604 
605 	TAILQ_FOREACH(h, &conf->hosts, vhosts) {
606 		printf("\nserver \"%s\" {\n", h->domain);
607 		printf("	cert \"%s\"\n", h->cert);
608 		printf("	key \"%s\"\n", h->key);
609 		/* TODO: print locations... */
610 		printf("}\n");
611 	}
612 }