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Date:: Sat Mar 30 17:21:23 2024 UTC
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1 /*
2  * Copyright (c) 2024 Stefan Sperling <stsp@openbsd.org>
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 "got_compat.h"
18 
19 #include <sys/types.h>
20 #include <sys/queue.h>
21 #include <sys/socket.h>
22 #include <sys/wait.h>
23 
24 #include <errno.h>
25 #include <event.h>
26 #include <limits.h>
27 #include <signal.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <imsg.h>
32 #include <unistd.h>
33 
34 #include "got_error.h"
35 #include "got_path.h"
36 
37 #include "gotd.h"
38 #include "log.h"
39 #include "notify.h"
40 
41 #ifndef nitems
42 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
43 #endif
44 
45 static struct gotd_notify {
46 	pid_t pid;
47 	const char *title;
48 	struct gotd_imsgev parent_iev;
49 	struct gotd_repolist *repos;
50 	const char *default_sender;
51 } gotd_notify;
52 
53 struct gotd_notify_session {
54 	STAILQ_ENTRY(gotd_notify_session) entry;
55 	uint32_t id;
56 	struct gotd_imsgev iev;
57 };
58 STAILQ_HEAD(gotd_notify_sessions, gotd_notify_session);
59 
60 static struct gotd_notify_sessions gotd_notify_sessions[GOTD_CLIENT_TABLE_SIZE];
61 static SIPHASH_KEY sessions_hash_key;
62 
63 static void gotd_notify_shutdown(void);
64 
65 static uint64_t
66 session_hash(uint32_t session_id)
67 {
68 	return SipHash24(&sessions_hash_key, &session_id, sizeof(session_id));
69 }
70 
71 static void
72 add_session(struct gotd_notify_session *session)
73 {
74 	uint64_t slot;
75 
76 	slot = session_hash(session->id) % nitems(gotd_notify_sessions);
77 	STAILQ_INSERT_HEAD(&gotd_notify_sessions[slot], session, entry);
78 }
79 
80 static struct gotd_notify_session *
81 find_session(uint32_t session_id)
82 {
83 	uint64_t slot;
84 	struct gotd_notify_session *s;
85 
86 	slot = session_hash(session_id) % nitems(gotd_notify_sessions);
87 	STAILQ_FOREACH(s, &gotd_notify_sessions[slot], entry) {
88 		if (s->id == session_id)
89 			return s;
90 	}
91 
92 	return NULL;
93 }
94 
95 static struct gotd_notify_session *
96 find_session_by_fd(int fd)
97 {
98 	uint64_t slot;
99 	struct gotd_notify_session *s;
100 
101 	for (slot = 0; slot < nitems(gotd_notify_sessions); slot++) {
102 		STAILQ_FOREACH(s, &gotd_notify_sessions[slot], entry) {
103 			if (s->iev.ibuf.fd == fd)
104 				return s;
105 		}
106 	}
107 
108 	return NULL;
109 }
110 
111 static void
112 remove_session(struct gotd_notify_session *session)
113 {
114 	uint64_t slot;
115 
116 	slot = session_hash(session->id) % nitems(gotd_notify_sessions);
117 	STAILQ_REMOVE(&gotd_notify_sessions[slot], session,
118 	    gotd_notify_session, entry);
119 	free(session);
120 }
121 
122 static uint32_t
123 get_session_id(void)
124 {
125 	int duplicate = 0;
126 	uint32_t id;
127 
128 	do {
129 		id = arc4random();
130 		duplicate = (find_session(id) != NULL);
131 	} while (duplicate || id == 0);
132 
133 	return id;
134 }
135 
136 static void
137 gotd_notify_sighdlr(int sig, short event, void *arg)
138 {
139 	/*
140 	 * Normal signal handler rules don't apply because libevent
141 	 * decouples for us.
142 	 */
143 
144 	switch (sig) {
145 	case SIGHUP:
146 		log_info("%s: ignoring SIGHUP", __func__);
147 		break;
148 	case SIGUSR1:
149 		log_info("%s: ignoring SIGUSR1", __func__);
150 		break;
151 	case SIGTERM:
152 	case SIGINT:
153 		gotd_notify_shutdown();
154 		/* NOTREACHED */
155 		break;
156 	default:
157 		fatalx("unexpected signal");
158 	}
159 }
160 
161 static void
162 run_notification_helper(const char *prog, const char **argv, int fd)
163 {
164 	const struct got_error *err = NULL;
165 	pid_t pid;
166 	int child_status;
167 
168 	pid = fork();
169 	if (pid == -1) {
170 		err = got_error_from_errno("fork");
171 		log_warn("%s", err->msg);
172 		return;
173 	} else if (pid == 0) {
174 		signal(SIGQUIT, SIG_DFL);
175 		signal(SIGINT, SIG_DFL);
176 		signal(SIGCHLD, SIG_DFL);
177 
178 		if (dup2(fd, STDIN_FILENO) == -1) {
179 			fprintf(stderr, "%s: dup2: %s\n", getprogname(),
180 			    strerror(errno));
181 			_exit(1);
182 		}
183 
184 		closefrom(STDERR_FILENO + 1);
185 
186 		if (execv(prog, (char *const *)argv) == -1) {
187 			fprintf(stderr, "%s: exec %s: %s\n", getprogname(),
188 			    prog, strerror(errno));
189 			_exit(1);
190 		}
191 
192 		/* not reached */
193 	}
194 
195 	if (waitpid(pid, &child_status, 0) == -1) {
196 		err = got_error_from_errno("waitpid");
197 		goto done;
198 	}
199 
200 	if (!WIFEXITED(child_status)) {
201 		err = got_error(GOT_ERR_PRIVSEP_DIED);
202 		goto done;
203 	}
204 
205 	if (WEXITSTATUS(child_status) != 0)
206 		err = got_error(GOT_ERR_PRIVSEP_EXIT);
207 done:
208 	if (err)
209 		log_warnx("%s: child %s pid %d: %s", gotd_notify.title,
210 		    prog, pid, err->msg);
211 }
212 
213 static void
214 notify_email(struct gotd_notification_target *target, const char *subject_line,
215     int fd)
216 {
217 	const char *argv[13];
218 	int i = 0;
219 
220 	argv[i++] = GOTD_PATH_PROG_NOTIFY_EMAIL;
221 
222 	argv[i++] = "-f";
223 	if (target->conf.email.sender)
224 		argv[i++] = target->conf.email.sender;
225 	else
226 		argv[i++] = gotd_notify.default_sender;
227 
228 	if (target->conf.email.responder) {
229 		argv[i++] = "-r";
230 		argv[i++] = target->conf.email.responder;
231 	}
232 
233 	if (target->conf.email.hostname) {
234 		argv[i++] = "-h";
235 		argv[i++] = target->conf.email.hostname;
236 	}
237 	
238 	if (target->conf.email.port) {
239 		argv[i++] = "-p";
240 		argv[i++] = target->conf.email.port;
241 	}
242 
243 	argv[i++] = "-s";
244 	argv[i++] = subject_line;
245 
246 	argv[i++] = target->conf.email.recipient;
247 
248 	argv[i] = NULL;
249 
250 	run_notification_helper(GOTD_PATH_PROG_NOTIFY_EMAIL, argv, fd);
251 }
252 
253 static void
254 notify_http(struct gotd_notification_target *target, const char *subject_line,
255     int fd)
256 {
257 	const char *argv[10] = { 0 }; /* TODO */
258 
259 	run_notification_helper(GOTD_PATH_PROG_NOTIFY_HTTP, argv, fd);
260 }
261 
262 static const struct got_error *
263 send_notification(struct imsg *imsg, struct gotd_imsgev *iev)
264 {
265 	const struct got_error *err = NULL;
266 	struct gotd_imsg_notify inotify;
267 	size_t datalen;
268 	struct gotd_repo *repo;
269 	struct gotd_notification_target *target;
270 	int fd;
271 
272 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
273 	if (datalen != sizeof(inotify))
274 		return got_error(GOT_ERR_PRIVSEP_LEN);
275 
276 	memcpy(&inotify, imsg->data, datalen);
277 
278 	repo = gotd_find_repo_by_name(inotify.repo_name, gotd_notify.repos);
279 	if (repo == NULL)
280 		return got_error(GOT_ERR_PRIVSEP_MSG);
281 
282 	fd = imsg_get_fd(imsg);
283 	if (fd == -1)
284 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
285 
286 	if (lseek(fd, 0, SEEK_SET) == -1) {
287 		err = got_error_from_errno("lseek");
288 		goto done;
289 	}
290 
291 	STAILQ_FOREACH(target, &repo->notification_targets, entry) {
292 		switch (target->type) {
293 		case GOTD_NOTIFICATION_VIA_EMAIL:
294 			notify_email(target, inotify.subject_line, fd);
295 			break;
296 		case GOTD_NOTIFICATION_VIA_HTTP:
297 			notify_http(target, inotify.subject_line, fd);
298 			break;
299 		}
300 	}
301 
302 	if (gotd_imsg_compose_event(iev, GOTD_IMSG_NOTIFICATION_SENT,
303 	    PROC_NOTIFY, -1, NULL, 0) == -1) {
304 		err = got_error_from_errno("imsg compose NOTIFY");
305 		goto done;
306 	}
307 done:
308 	close(fd);
309 	return err;
310 }
311 
312 static void
313 notify_dispatch_session(int fd, short event, void *arg)
314 {
315 	struct gotd_imsgev *iev = arg;
316 	struct imsgbuf *ibuf = &iev->ibuf;
317 	ssize_t n;
318 	int shut = 0;
319 	struct imsg imsg;
320 
321 	if (event & EV_READ) {
322 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
323 			fatal("imsg_read error");
324 		if (n == 0) {
325 			/* Connection closed. */
326 			shut = 1;
327 			goto done;
328 		}
329 	}
330 
331 	if (event & EV_WRITE) {
332 		n = msgbuf_write(&ibuf->w);
333 		if (n == -1 && errno != EAGAIN)
334 			fatal("msgbuf_write");
335 		if (n == 0) {
336 			/* Connection closed. */
337 			shut = 1;
338 			goto done;
339 		}
340 	}
341 
342 	for (;;) {
343 		const struct got_error *err = NULL;
344 
345 		if ((n = imsg_get(ibuf, &imsg)) == -1)
346 			fatal("%s: imsg_get error", __func__);
347 		if (n == 0)	/* No more messages. */
348 			break;
349 
350 		switch (imsg.hdr.type) {
351 		case GOTD_IMSG_NOTIFY:
352 			err = send_notification(&imsg, iev);
353 			break;
354 		default:
355 			log_debug("unexpected imsg %d", imsg.hdr.type);
356 			break;
357 		}
358 		imsg_free(&imsg);
359 
360 		if (err)
361 			log_warnx("%s: %s", __func__, err->msg);
362 	}
363 done:
364 	if (!shut) {
365 		gotd_imsg_event_add(iev);
366 	} else {
367 		struct gotd_notify_session *session;
368 
369 		/* This pipe is dead. Remove its event handler */
370 		event_del(&iev->ev);
371 		imsg_clear(&iev->ibuf);
372 
373 		session = find_session_by_fd(fd);
374 		if (session)
375 			remove_session(session);
376 	}
377 }
378 
379 static const struct got_error *
380 recv_session(struct imsg *imsg)
381 {
382 	struct gotd_notify_session *session;
383 	size_t datalen;
384 	int fd;
385 
386 	datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
387 	if (datalen != 0)
388 		return got_error(GOT_ERR_PRIVSEP_LEN);
389 
390 	fd = imsg_get_fd(imsg);
391 	if (fd == -1)
392 		return got_error(GOT_ERR_PRIVSEP_NO_FD);
393 
394 	session = calloc(1, sizeof(*session));
395 	if (session == NULL)
396 		return got_error_from_errno("calloc");
397 
398 	session->id = get_session_id();
399 	imsg_init(&session->iev.ibuf, fd);
400 	session->iev.handler = notify_dispatch_session;
401 	session->iev.events = EV_READ;
402 	session->iev.handler_arg = NULL;
403 	event_set(&session->iev.ev, session->iev.ibuf.fd, EV_READ,
404 	    notify_dispatch_session, &session->iev);
405 	gotd_imsg_event_add(&session->iev);
406 	add_session(session);
407 
408 	return NULL;
409 }
410 
411 static void
412 notify_dispatch(int fd, short event, void *arg)
413 {
414 	struct gotd_imsgev *iev = arg;
415 	struct imsgbuf *ibuf = &iev->ibuf;
416 	ssize_t n;
417 	int shut = 0;
418 	struct imsg imsg;
419 
420 	if (event & EV_READ) {
421 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
422 			fatal("imsg_read error");
423 		if (n == 0) {
424 			/* Connection closed. */
425 			shut = 1;
426 			goto done;
427 		}
428 	}
429 
430 	if (event & EV_WRITE) {
431 		n = msgbuf_write(&ibuf->w);
432 		if (n == -1 && errno != EAGAIN)
433 			fatal("msgbuf_write");
434 		if (n == 0) {
435 			/* Connection closed. */
436 			shut = 1;
437 			goto done;
438 		}
439 	}
440 
441 	for (;;) {
442 		const struct got_error *err = NULL;
443 
444 		if ((n = imsg_get(ibuf, &imsg)) == -1)
445 			fatal("%s: imsg_get error", __func__);
446 		if (n == 0)	/* No more messages. */
447 			break;
448 
449 		switch (imsg.hdr.type) {
450 		case GOTD_IMSG_CONNECT_SESSION:
451 			err = recv_session(&imsg);
452 			break;
453 		default:
454 			log_debug("unexpected imsg %d", imsg.hdr.type);
455 			break;
456 		}
457 		imsg_free(&imsg);
458 
459 		if (err)
460 			log_warnx("%s: %s", __func__, err->msg);
461 	}
462 done:
463 	if (!shut) {
464 		gotd_imsg_event_add(iev);
465 	} else {
466 		/* This pipe is dead. Remove its event handler */
467 		event_del(&iev->ev);
468 		event_loopexit(NULL);
469 	}
470 
471 }
472 
473 void
474 notify_main(const char *title, struct gotd_repolist *repos,
475     const char *default_sender)
476 {
477 	const struct got_error *err = NULL;
478 	struct event evsigint, evsigterm, evsighup, evsigusr1;
479 
480 	arc4random_buf(&sessions_hash_key, sizeof(sessions_hash_key));
481 
482 	gotd_notify.title = title;
483 	gotd_notify.repos = repos;
484 	gotd_notify.default_sender = default_sender;
485 	gotd_notify.pid = getpid();
486 
487 	signal_set(&evsigint, SIGINT, gotd_notify_sighdlr, NULL);
488 	signal_set(&evsigterm, SIGTERM, gotd_notify_sighdlr, NULL);
489 	signal_set(&evsighup, SIGHUP, gotd_notify_sighdlr, NULL);
490 	signal_set(&evsigusr1, SIGUSR1, gotd_notify_sighdlr, NULL);
491 	signal(SIGPIPE, SIG_IGN);
492 
493 	signal_add(&evsigint, NULL);
494 	signal_add(&evsigterm, NULL);
495 	signal_add(&evsighup, NULL);
496 	signal_add(&evsigusr1, NULL);
497 
498 	imsg_init(&gotd_notify.parent_iev.ibuf, GOTD_FILENO_MSG_PIPE);
499 	gotd_notify.parent_iev.handler = notify_dispatch;
500 	gotd_notify.parent_iev.events = EV_READ;
501 	gotd_notify.parent_iev.handler_arg = NULL;
502 	event_set(&gotd_notify.parent_iev.ev, gotd_notify.parent_iev.ibuf.fd,
503 	    EV_READ, notify_dispatch, &gotd_notify.parent_iev);
504 	gotd_imsg_event_add(&gotd_notify.parent_iev);
505 
506 	event_dispatch();
507 
508 	if (err)
509 		log_warnx("%s: %s", title, err->msg);
510 	gotd_notify_shutdown();
511 }
512 
513 void
514 gotd_notify_shutdown(void)
515 {
516 	log_debug("%s: shutting down", gotd_notify.title);
517 	exit(0);
518 }