1 /*
2  * Copyright (c) 2010 - 2016 Reyk Floeter <reyk@openbsd.org>
3  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@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 #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 <fcntl.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <unistd.h>
28 #include <string.h>
29 #include <errno.h>
30 #include <signal.h>
31 #include <pwd.h>
32 #include <event.h>
33 
34 #include "proc.h"
35 
36 void	 proc_exec(struct privsep *, struct privsep_proc *, unsigned int,
37 	    int, char **);
38 void	 proc_setup(struct privsep *, struct privsep_proc *, unsigned int);
39 void	 proc_open(struct privsep *, int, int);
40 void	 proc_accept(struct privsep *, int, enum privsep_procid,
41 	    unsigned int);
42 void	 proc_close(struct privsep *);
43 int	 proc_ispeer(struct privsep_proc *, unsigned int, enum privsep_procid);
44 void	 proc_shutdown(struct privsep_proc *);
45 void	 proc_sig_handler(int, short, void *);
46 int	 proc_dispatch_null(int, struct privsep_proc *, struct imsg *);
47 
48 enum privsep_procid privsep_process;
49 
50 int
51 proc_ispeer(struct privsep_proc *procs, unsigned int nproc,
52     enum privsep_procid type)
53 {
54 	unsigned int i;
55 
56 	for (i = 0; i < nproc; i++)
57 		if (procs[i].p_id == type)
58 			return (1);
59 
60 	return (0);
61 }
62 
63 enum privsep_procid
64 proc_getid(struct privsep_proc *procs, unsigned int nproc,
65     const char *proc_name)
66 {
67 	struct privsep_proc *p;
68 	unsigned int proc;
69 
70 	for (proc = 0; proc < nproc; proc++) {
71 		p = &procs[proc];
72 		if (strcmp(p->p_title, proc_name))
73 			continue;
74 
75 		return (p->p_id);
76 	}
77 
78 	return (PROC_MAX);
79 }
80 
81 void
82 proc_exec(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc,
83     int argc, char **argv)
84 {
85 	unsigned int proc, nargc, i, proc_i;
86 	char **nargv;
87 	struct privsep_proc *p;
88 	char num[32];
89 	int fd;
90 
91 	/* Prepare the new process argv. */
92 	nargv = calloc(argc + 5, sizeof(char *));
93 	if (nargv == NULL)
94 		fatal("%s: calloc", __func__);
95 
96 	/* Copy call argument first. */
97 	nargc = 0;
98 	nargv[nargc++] = argv[0];
99 
100 	/* Set process name argument and save the position. */
101 	nargv[nargc] = strdup("-P");
102 	if (nargv[nargc] == NULL)
103 		fatal("%s: strdup", __func__);
104 	nargc++;
105 	proc_i = nargc;
106 	nargc++;
107 
108 	/* Point process instance arg to stack and copy the original args. */
109 	nargv[nargc] = strdup("-I");
110 	if (nargv[nargc] == NULL)
111 		fatal("%s: strdup", __func__);
112 	nargc++;
113 	nargv[nargc++] = num;
114 	for (i = 1; i < (unsigned int) argc; i++)
115 		nargv[nargc++] = argv[i];
116 
117 	nargv[nargc] = NULL;
118 
119 	for (proc = 0; proc < nproc; proc++) {
120 		p = &procs[proc];
121 
122 		/* Update args with process title. */
123 		nargv[proc_i] = (char *)(uintptr_t)p->p_title;
124 
125 		/* Fire children processes. */
126 		for (i = 0; i < ps->ps_instances[p->p_id]; i++) {
127 			/* Update the process instance number. */
128 			snprintf(num, sizeof(num), "%u", i);
129 
130 			fd = ps->ps_pipes[p->p_id][i].pp_pipes[PROC_GOTWEBD][0];
131 			ps->ps_pipes[p->p_id][i].pp_pipes[PROC_GOTWEBD][0] = -1;
132 
133 			switch (fork()) {
134 			case -1:
135 				fatal("%s: fork", __func__);
136 				break;
137 			case 0:
138 				/* First create a new session */
139 				if (setsid() == -1)
140 					fatal("setsid");
141 
142 				/* Prepare parent socket. */
143 				if (fd != PROC_GOTWEBD_SOCK_FILENO) {
144 					if (dup2(fd, PROC_GOTWEBD_SOCK_FILENO)
145 					    == -1)
146 						fatal("dup2");
147 				} else if (fcntl(fd, F_SETFD, 0) == -1)
148 					fatal("fcntl");
149 
150 				execvp(argv[0], nargv);
151 				fatal("%s: execvp", __func__);
152 				break;
153 			default:
154 				/* Close child end. */
155 				close(fd);
156 				break;
157 			}
158 		}
159 	}
160 
161 	free(nargv);
162 }
163 
164 void
165 proc_connect(struct privsep *ps)
166 {
167 	struct imsgev *iev;
168 	unsigned int src, dst, inst;
169 
170 	/* Don't distribute any sockets if we are not really going to run. */
171 	if (ps->ps_noaction)
172 		return;
173 
174 	for (dst = 0; dst < PROC_MAX; dst++) {
175 		/* We don't communicate with ourselves. */
176 		if (dst == PROC_GOTWEBD)
177 			continue;
178 
179 		for (inst = 0; inst < ps->ps_instances[dst]; inst++) {
180 			iev = &ps->ps_ievs[dst][inst];
181 			imsg_init(&iev->ibuf, ps->ps_pp->pp_pipes[dst][inst]);
182 			event_set(&iev->ev, iev->ibuf.fd, iev->events,
183 			    iev->handler, iev->data);
184 			event_add(&iev->ev, NULL);
185 		}
186 	}
187 
188 	/* Distribute the socketpair()s for everyone. */
189 	for (src = 0; src < PROC_MAX; src++)
190 		for (dst = src; dst < PROC_MAX; dst++) {
191 			/* Parent already distributed its fds. */
192 			if (src == PROC_GOTWEBD || dst == PROC_GOTWEBD)
193 				continue;
194 
195 			proc_open(ps, src, dst);
196 		}
197 }
198 
199 void
200 proc_init(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc,
201     int argc, char **argv, enum privsep_procid proc_id)
202 {
203 	struct privsep_proc *p = NULL;
204 	struct privsep_pipes *pa, *pb;
205 	unsigned int proc;
206 	unsigned int dst;
207 	int fds[2];
208 
209 	/* Don't initiate anything if we are not really going to run. */
210 	if (ps->ps_noaction)
211 		return;
212 
213 	if (proc_id == PROC_GOTWEBD) {
214 		privsep_process = PROC_GOTWEBD;
215 		proc_setup(ps, procs, nproc);
216 
217 		/*
218 		 * Create the children sockets so we can use them
219 		 * to distribute the rest of the socketpair()s using
220 		 * proc_connect() later.
221 		 */
222 		for (dst = 0; dst < PROC_MAX; dst++) {
223 			/* Don't create socket for ourselves. */
224 			if (dst == PROC_GOTWEBD)
225 				continue;
226 
227 			for (proc = 0; proc < ps->ps_instances[dst]; proc++) {
228 				pa = &ps->ps_pipes[PROC_GOTWEBD][0];
229 				pb = &ps->ps_pipes[dst][proc];
230 				int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
231 #ifdef SOCK_CLOEXEC
232 				sock_flags |= SOCK_CLOEXEC;
233 #endif
234 				if (socketpair(AF_UNIX, sock_flags,
235 				    PF_UNSPEC, fds) == -1)
236 					fatal("%s: socketpair", __func__);
237 
238 				pa->pp_pipes[dst][proc] = fds[0];
239 				pb->pp_pipes[PROC_GOTWEBD][0] = fds[1];
240 			}
241 		}
242 
243 		/* Engage! */
244 		proc_exec(ps, procs, nproc, argc, argv);
245 		return;
246 	}
247 
248 	/* Initialize a child */
249 	for (proc = 0; proc < nproc; proc++) {
250 		if (procs[proc].p_id != proc_id)
251 			continue;
252 		p = &procs[proc];
253 		break;
254 	}
255 	if (p == NULL || p->p_init == NULL)
256 		fatalx("%s: process %d missing process initialization",
257 		    __func__, proc_id);
258 
259 	p->p_init(ps, p);
260 
261 	fatalx("failed to initiate child process");
262 }
263 
264 void
265 proc_accept(struct privsep *ps, int fd, enum privsep_procid dst,
266     unsigned int n)
267 {
268 	struct privsep_pipes *pp = ps->ps_pp;
269 	struct imsgev *iev;
270 
271 	if (ps->ps_ievs[dst] == NULL) {
272 #if DEBUG > 1
273 		log_debug("%s: %s src %d %d to dst %d %d not connected",
274 		    __func__, ps->ps_title[privsep_process],
275 		    privsep_process, ps->ps_instance + 1,
276 		    dst, n + 1);
277 #endif
278 		close(fd);
279 		return;
280 	}
281 
282 	if (pp->pp_pipes[dst][n] != -1) {
283 		log_warnx("%s: duplicated descriptor", __func__);
284 		close(fd);
285 		return;
286 	} else
287 		pp->pp_pipes[dst][n] = fd;
288 
289 	iev = &ps->ps_ievs[dst][n];
290 	imsg_init(&iev->ibuf, fd);
291 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
292 	event_add(&iev->ev, NULL);
293 }
294 
295 void
296 proc_setup(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc)
297 {
298 	unsigned int i, j, src, dst, id;
299 	struct privsep_pipes *pp;
300 
301 	/* Initialize parent title, ps_instances and procs. */
302 	ps->ps_title[PROC_GOTWEBD] = "parent";
303 
304 	for (src = 0; src < PROC_MAX; src++)
305 		/* Default to 1 process instance */
306 		if (ps->ps_instances[src] < 1)
307 			ps->ps_instances[src] = 1;
308 
309 	for (src = 0; src < nproc; src++) {
310 		procs[src].p_ps = ps;
311 		if (procs[src].p_cb == NULL)
312 			procs[src].p_cb = proc_dispatch_null;
313 
314 		id = procs[src].p_id;
315 		ps->ps_title[id] = procs[src].p_title;
316 		ps->ps_ievs[id] = calloc(ps->ps_instances[id],
317 		    sizeof(struct imsgev));
318 		if (ps->ps_ievs[id] == NULL)
319 			fatal("%s: calloc", __func__);
320 
321 		/* With this set up, we are ready to call imsg_init(). */
322 		for (i = 0; i < ps->ps_instances[id]; i++) {
323 			ps->ps_ievs[id][i].handler = proc_dispatch;
324 			ps->ps_ievs[id][i].events = EV_READ;
325 			ps->ps_ievs[id][i].proc = &procs[src];
326 			ps->ps_ievs[id][i].data = &ps->ps_ievs[id][i];
327 		}
328 	}
329 
330 	/*
331 	 * Allocate pipes for all process instances (incl. parent)
332 	 *
333 	 * - ps->ps_pipes: N:M mapping
334 	 * N source processes connected to M destination processes:
335 	 * [src][instances][dst][instances], for example
336 	 * [PROC_RELAY][3][PROC_CA][3]
337 	 *
338 	 * - ps->ps_pp: per-process 1:M part of ps->ps_pipes
339 	 * Each process instance has a destination array of socketpair fds:
340 	 * [dst][instances], for example
341 	 * [PROC_GOTWEBD][0]
342 	 */
343 	for (src = 0; src < PROC_MAX; src++) {
344 		/* Allocate destination array for each process */
345 		ps->ps_pipes[src] = calloc(ps->ps_instances[src],
346 		    sizeof(struct privsep_pipes));
347 		if (ps->ps_pipes[src] == NULL)
348 			fatal("%s: calloc", __func__);
349 
350 		for (i = 0; i < ps->ps_instances[src]; i++) {
351 			pp = &ps->ps_pipes[src][i];
352 
353 			for (dst = 0; dst < PROC_MAX; dst++) {
354 				/* Allocate maximum fd integers */
355 				pp->pp_pipes[dst] =
356 				    calloc(ps->ps_instances[dst],
357 				    sizeof(int));
358 				if (pp->pp_pipes[dst] == NULL)
359 					fatal("%s: calloc", __func__);
360 
361 				/* Mark fd as unused */
362 				for (j = 0; j < ps->ps_instances[dst]; j++)
363 					pp->pp_pipes[dst][j] = -1;
364 			}
365 		}
366 	}
367 
368 	ps->ps_pp = &ps->ps_pipes[privsep_process][ps->ps_instance];
369 }
370 
371 void
372 proc_kill(struct privsep *ps)
373 {
374 	char *cause;
375 	pid_t pid;
376 	int len, status;
377 
378 	if (privsep_process != PROC_GOTWEBD)
379 		return;
380 
381 	proc_close(ps);
382 
383 	do {
384 		pid = waitpid(WAIT_ANY, &status, 0);
385 		if (pid <= 0)
386 			continue;
387 
388 		if (WIFSIGNALED(status)) {
389 			len = asprintf(&cause, "terminated; signal %d",
390 			    WTERMSIG(status));
391 		} else if (WIFEXITED(status)) {
392 			if (WEXITSTATUS(status) != 0)
393 				len = asprintf(&cause, "exited abnormally");
394 			else
395 				len = 0;
396 		} else
397 			len = -1;
398 
399 		if (len == 0) {
400 			/* child exited OK, don't print a warning message */
401 		} else if (len != -1) {
402 			log_warnx("lost child: pid %u %s", pid, cause);
403 			free(cause);
404 		} else
405 			log_warnx("lost child: pid %u", pid);
406 	} while (pid != -1 || (pid == -1 && errno == EINTR));
407 }
408 
409 void
410 proc_open(struct privsep *ps, int src, int dst)
411 {
412 	struct privsep_pipes *pa, *pb;
413 	struct privsep_fd pf;
414 	int fds[2];
415 	unsigned int i, j;
416 
417 	/* Exchange pipes between process. */
418 	for (i = 0; i < ps->ps_instances[src]; i++) {
419 		for (j = 0; j < ps->ps_instances[dst]; j++) {
420 			/* Don't create sockets for ourself. */
421 			if (src == dst && i == j)
422 				continue;
423 
424 			pa = &ps->ps_pipes[src][i];
425 			pb = &ps->ps_pipes[dst][j];
426 			int sock_flags = SOCK_STREAM | SOCK_NONBLOCK;
427 #ifdef SOCK_CLOEXEC
428 			sock_flags |= SOCK_CLOEXEC;
429 #endif
430 			if (socketpair(AF_UNIX, sock_flags,
431 			    PF_UNSPEC, fds) == -1)
432 				fatal("%s: socketpair", __func__);
433 
434 			pa->pp_pipes[dst][j] = fds[0];
435 			pb->pp_pipes[src][i] = fds[1];
436 
437 			pf.pf_procid = src;
438 			pf.pf_instance = i;
439 			if (proc_compose_imsg(ps, dst, j, IMSG_CTL_PROCFD,
440 			    -1, pb->pp_pipes[src][i], &pf, sizeof(pf)) == -1)
441 				fatal("%s: proc_compose_imsg", __func__);
442 
443 			pf.pf_procid = dst;
444 			pf.pf_instance = j;
445 			if (proc_compose_imsg(ps, src, i, IMSG_CTL_PROCFD,
446 			    -1, pa->pp_pipes[dst][j], &pf, sizeof(pf)) == -1)
447 				fatal("%s: proc_compose_imsg", __func__);
448 
449 			/*
450 			 * We have to flush to send the descriptors and close
451 			 * them to avoid the fd ramp on startup.
452 			 */
453 			if (proc_flush_imsg(ps, src, i) == -1 ||
454 			    proc_flush_imsg(ps, dst, j) == -1)
455 				fatal("%s: imsg_flush", __func__);
456 		}
457 	}
458 }
459 
460 void
461 proc_close(struct privsep *ps)
462 {
463 	unsigned int dst, n;
464 	struct privsep_pipes *pp;
465 
466 	if (ps == NULL)
467 		return;
468 
469 	pp = ps->ps_pp;
470 
471 	for (dst = 0; dst < PROC_MAX; dst++) {
472 		if (ps->ps_ievs[dst] == NULL)
473 			continue;
474 
475 		for (n = 0; n < ps->ps_instances[dst]; n++) {
476 			if (pp->pp_pipes[dst][n] == -1)
477 				continue;
478 
479 			/* Cancel the fd, close and invalidate the fd */
480 			event_del(&(ps->ps_ievs[dst][n].ev));
481 			imsg_clear(&(ps->ps_ievs[dst][n].ibuf));
482 			close(pp->pp_pipes[dst][n]);
483 			pp->pp_pipes[dst][n] = -1;
484 		}
485 		free(ps->ps_ievs[dst]);
486 	}
487 }
488 
489 void
490 proc_shutdown(struct privsep_proc *p)
491 {
492 	struct privsep *ps = p->p_ps;
493 
494 	if (p->p_shutdown != NULL)
495 		(*p->p_shutdown)();
496 
497 	proc_close(ps);
498 
499 	log_info("%s, %s exiting, pid %d", getprogname(), p->p_title, getpid());
500 
501 	exit(0);
502 }
503 
504 void
505 proc_sig_handler(int sig, short event, void *arg)
506 {
507 	struct privsep_proc *p = arg;
508 
509 	switch (sig) {
510 	case SIGINT:
511 	case SIGTERM:
512 		proc_shutdown(p);
513 		break;
514 	case SIGCHLD:
515 	case SIGHUP:
516 	case SIGPIPE:
517 	case SIGUSR1:
518 		/* ignore */
519 		break;
520 	default:
521 		fatalx("proc_sig_handler: unexpected signal");
522 		/* NOTREACHED */
523 	}
524 }
525 
526 void
527 proc_run(struct privsep *ps, struct privsep_proc *p,
528     struct privsep_proc *procs, unsigned int nproc,
529     void (*run)(struct privsep *, struct privsep_proc *, void *), void *arg)
530 {
531 	struct passwd *pw;
532 	const char *root;
533 
534 	log_procinit(p->p_title);
535 
536 	/* Set the process group of the current process */
537 	setpgid(0, 0);
538 
539 	/* Use non-standard user */
540 	if (p->p_pw != NULL)
541 		pw = p->p_pw;
542 	else
543 		pw = ps->ps_pw;
544 
545 	/* Change root directory */
546 	if (p->p_chroot != NULL)
547 		root = p->p_chroot;
548 	else
549 		root = pw->pw_dir;
550 
551 	if (chroot(root) == -1)
552 		fatal("proc_run: chroot");
553 	if (chdir("/") == -1)
554 		fatal("proc_run: chdir(\"/\")");
555 
556 	privsep_process = p->p_id;
557 
558 	setproctitle("%s", p->p_title);
559 
560 	if (setgroups(1, &pw->pw_gid) ||
561 	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
562 	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
563 		fatal("proc_run: cannot drop privileges");
564 
565 	event_init();
566 
567 	signal_set(&ps->ps_evsigint, SIGINT, proc_sig_handler, p);
568 	signal_set(&ps->ps_evsigterm, SIGTERM, proc_sig_handler, p);
569 	signal_set(&ps->ps_evsigchld, SIGCHLD, proc_sig_handler, p);
570 	signal_set(&ps->ps_evsighup, SIGHUP, proc_sig_handler, p);
571 	signal_set(&ps->ps_evsigpipe, SIGPIPE, proc_sig_handler, p);
572 	signal_set(&ps->ps_evsigusr1, SIGUSR1, proc_sig_handler, p);
573 
574 	signal_add(&ps->ps_evsigint, NULL);
575 	signal_add(&ps->ps_evsigterm, NULL);
576 	signal_add(&ps->ps_evsigchld, NULL);
577 	signal_add(&ps->ps_evsighup, NULL);
578 	signal_add(&ps->ps_evsigpipe, NULL);
579 	signal_add(&ps->ps_evsigusr1, NULL);
580 
581 	proc_setup(ps, procs, nproc);
582 	proc_accept(ps, PROC_GOTWEBD_SOCK_FILENO, PROC_GOTWEBD, 0);
583 
584 	DPRINTF("%s: %s %d/%d, pid %d", __func__, p->p_title,
585 	    ps->ps_instance + 1, ps->ps_instances[p->p_id], getpid());
586 
587 	if (run != NULL)
588 		run(ps, p, arg);
589 
590 	event_dispatch();
591 
592 	proc_shutdown(p);
593 }
594 
595 void
596 proc_dispatch(int fd, short event, void *arg)
597 {
598 	struct imsgev *iev = arg;
599 	struct privsep_proc *p = iev->proc;
600 	struct privsep *ps = p->p_ps;
601 	struct imsgbuf *ibuf;
602 	struct imsg imsg;
603 	ssize_t n;
604 	int verbose;
605 	const char *title;
606 	struct privsep_fd pf;
607 
608 	title = ps->ps_title[privsep_process];
609 	ibuf = &iev->ibuf;
610 
611 	if (event & EV_READ) {
612 		n = imsg_read(ibuf);
613 		if (n == -1 && errno != EAGAIN)
614 			fatal("%s: imsg_read", __func__);
615 		if (n == 0) {
616 			/* this pipe is dead, so remove the event handler */
617 			event_del(&iev->ev);
618 			event_loopexit(NULL);
619 			return;
620 		}
621 	}
622 
623 	if (event & EV_WRITE) {
624 		n = msgbuf_write(&ibuf->w);
625 		if (n == -1 && errno != EAGAIN)
626 			fatal("%s: msgbuf_write", __func__);
627 		if (n == 0) {
628 			/* this pipe is dead, so remove the event handler */
629 			event_del(&iev->ev);
630 			event_loopexit(NULL);
631 			return;
632 		}
633 	}
634 
635 	for (;;) {
636 		n = imsg_get(ibuf, &imsg);
637 		if (n == -1)
638 			fatal("%s: imsg_get", __func__);
639 		if (n == 0)
640 			break;
641 
642 #if DEBUG > 1
643 		log_debug("%s: %s %d got imsg %d peerid %d from %s %d",
644 		    __func__, title, ps->ps_instance + 1,
645 		    imsg.hdr.type, imsg.hdr.peerid, p->p_title, imsg.hdr.pid);
646 #endif
647 
648 		/*
649 		 * Check the message with the program callback
650 		 */
651 		if ((p->p_cb)(fd, p, &imsg) == 0) {
652 			/* Message was handled by the callback, continue */
653 			imsg_free(&imsg);
654 			continue;
655 		}
656 
657 		/*
658 		 * Generic message handling
659 		 */
660 		switch (imsg.hdr.type) {
661 		case IMSG_CTL_VERBOSE:
662 			log_info("%s", __func__);
663 			IMSG_SIZE_CHECK(&imsg, &verbose);
664 			memcpy(&verbose, imsg.data, sizeof(verbose));
665 			log_setverbose(verbose);
666 			break;
667 		case IMSG_CTL_PROCFD:
668 			IMSG_SIZE_CHECK(&imsg, &pf);
669 			memcpy(&pf, imsg.data, sizeof(pf));
670 			proc_accept(ps, imsg.fd, pf.pf_procid,
671 			    pf.pf_instance);
672 			break;
673 		default:
674 			log_warnx("%s: %s %d got invalid imsg %d peerid %d "
675 			    "from %s %d",
676 			    __func__, title, ps->ps_instance + 1,
677 			    imsg.hdr.type, imsg.hdr.peerid,
678 			    p->p_title, imsg.hdr.pid);
679 		}
680 		imsg_free(&imsg);
681 	}
682 	imsg_event_add(iev);
683 }
684 
685 int
686 proc_dispatch_null(int fd, struct privsep_proc *p, struct imsg *imsg)
687 {
688 	return (-1);
689 }
690 
691 /*
692  * imsg helper functions
693  */
694 
695 void
696 imsg_event_add(struct imsgev *iev)
697 {
698 	if (iev->handler == NULL) {
699 		imsg_flush(&iev->ibuf);
700 		return;
701 	}
702 
703 	iev->events = EV_READ;
704 	if (iev->ibuf.w.queued)
705 		iev->events |= EV_WRITE;
706 
707 	event_del(&iev->ev);
708 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
709 	event_add(&iev->ev, NULL);
710 }
711 
712 int
713 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
714     pid_t pid, int fd, void *data, uint16_t datalen)
715 {
716 	int ret;
717 
718 	ret = imsg_compose(&iev->ibuf, type, peerid, pid, fd, data, datalen);
719 	if (ret == -1)
720 		return (ret);
721 	imsg_event_add(iev);
722 	return (ret);
723 }
724 
725 int
726 imsg_composev_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
727     pid_t pid, int fd, const struct iovec *iov, int iovcnt)
728 {
729 	int ret;
730 
731 	ret = imsg_composev(&iev->ibuf, type, peerid, pid, fd, iov, iovcnt);
732 	if (ret == -1)
733 		return (ret);
734 	imsg_event_add(iev);
735 	return (ret);
736 }
737 
738 void
739 proc_range(struct privsep *ps, enum privsep_procid id, int *n, int *m)
740 {
741 	if (*n == -1) {
742 		/* Use a range of all target instances */
743 		*n = 0;
744 		*m = ps->ps_instances[id];
745 	} else {
746 		/* Use only a single slot of the specified peer process */
747 		*m = *n + 1;
748 	}
749 }
750 
751 int
752 proc_compose_imsg(struct privsep *ps, enum privsep_procid id, int n,
753     uint16_t type, uint32_t peerid, int fd, void *data, uint16_t datalen)
754 {
755 	int m;
756 
757 	proc_range(ps, id, &n, &m);
758 	for (; n < m; n++) {
759 		if (imsg_compose_event(&ps->ps_ievs[id][n],
760 		    type, peerid, ps->ps_instance + 1, fd, data, datalen) == -1)
761 			return (-1);
762 	}
763 
764 	return (0);
765 }
766 
767 int
768 proc_compose(struct privsep *ps, enum privsep_procid id,
769     uint16_t type, void *data, uint16_t datalen)
770 {
771 	return (proc_compose_imsg(ps, id, -1, type, -1, -1, data, datalen));
772 }
773 
774 int
775 proc_composev_imsg(struct privsep *ps, enum privsep_procid id, int n,
776     uint16_t type, uint32_t peerid, int fd, const struct iovec *iov, int iovcnt)
777 {
778 	int m;
779 
780 	proc_range(ps, id, &n, &m);
781 	for (; n < m; n++)
782 		if (imsg_composev_event(&ps->ps_ievs[id][n],
783 		    type, peerid, ps->ps_instance + 1, fd, iov, iovcnt) == -1)
784 			return (-1);
785 
786 	return (0);
787 }
788 
789 int
790 proc_composev(struct privsep *ps, enum privsep_procid id,
791     uint16_t type, const struct iovec *iov, int iovcnt)
792 {
793 	return (proc_composev_imsg(ps, id, -1, type, -1, -1, iov, iovcnt));
794 }
795 
796 int
797 proc_forward_imsg(struct privsep *ps, struct imsg *imsg,
798     enum privsep_procid id, int n)
799 {
800 	return (proc_compose_imsg(ps, id, n, imsg->hdr.type,
801 	    imsg->hdr.peerid, imsg->fd, imsg->data, IMSG_DATA_SIZE(imsg)));
802 }
803 
804 struct imsgbuf *
805 proc_ibuf(struct privsep *ps, enum privsep_procid id, int n)
806 {
807 	int m;
808 
809 	proc_range(ps, id, &n, &m);
810 	return (&ps->ps_ievs[id][n].ibuf);
811 }
812 
813 struct imsgev *
814 proc_iev(struct privsep *ps, enum privsep_procid id, int n)
815 {
816 	int m;
817 
818 	proc_range(ps, id, &n, &m);
819 	return (&ps->ps_ievs[id][n]);
820 }
821 
822 /* This function should only be called with care as it breaks async I/O */
823 int
824 proc_flush_imsg(struct privsep *ps, enum privsep_procid id, int n)
825 {
826 	struct imsgbuf *ibuf;
827 	int m, ret = 0;
828 
829 	proc_range(ps, id, &n, &m);
830 	for (; n < m; n++) {
831 		ibuf = proc_ibuf(ps, id, n);
832 		if (ibuf == NULL)
833 			return (-1);
834 		do {
835 			ret = imsg_flush(ibuf);
836 		} while (ret == -1 && errno == EAGAIN);
837 		if (ret == -1)
838 			break;
839 		imsg_event_add(&ps->ps_ievs[id][n]);
840 	}
841 
842 	return (ret);
843 }