1 /*	$OpenBSD: proc.c,v 1.41 2021/12/04 06:52:58 florian Exp $	*/
2 
3 /*
4  * Copyright (c) 2010 - 2016 Reyk Floeter <reyk@openbsd.org>
5  * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
6  *
7  * Permission to use, copy, modify, and distribute this software for any
8  * purpose with or without fee is hereby granted, provided that the above
9  * copyright notice and this permission notice appear in all copies.
10  *
11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18  */
19 
20 #include <sys/types.h>
21 #include <sys/queue.h>
22 #include <sys/tree.h>
23 #include <sys/socket.h>
24 #include <sys/wait.h>
25 
26 #include <fcntl.h>
27 #include <grp.h>
28 #include <limits.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <unistd.h>
32 #include <string.h>
33 #include <errno.h>
34 #include <signal.h>
35 #include <paths.h>
36 #include <pwd.h>
37 #include <event.h>
38 #include <imsg.h>
39 
40 #include "log.h"
41 #include "proc.h"
42 
43 #include "galileo.h"
44 
45 void	 proc_exec(struct privsep *, struct privsep_proc *, unsigned int, int,
46 	    int, char **);
47 void	 proc_setup(struct privsep *, struct privsep_proc *, unsigned int);
48 void	 proc_open(struct privsep *, int, int);
49 void	 proc_accept(struct privsep *, int, enum privsep_procid,
50 	    unsigned int);
51 void	 proc_close(struct privsep *);
52 void	 proc_shutdown(struct privsep_proc *);
53 void	 proc_sig_handler(int, short, void *);
54 void	 proc_range(struct privsep *, enum privsep_procid, int *, int *);
55 int	 proc_dispatch_null(int, struct privsep_proc *, struct imsg *);
56 
57 enum privsep_procid
58 proc_getid(struct privsep_proc *procs, unsigned int nproc,
59     const char *proc_name)
60 {
61 	struct privsep_proc	*p;
62 	unsigned int		 proc;
63 
64 	for (proc = 0; proc < nproc; proc++) {
65 		p = &procs[proc];
66 		if (strcmp(p->p_title, proc_name))
67 			continue;
68 
69 		return (p->p_id);
70 	}
71 
72 	return (PROC_MAX);
73 }
74 
75 void
76 proc_exec(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc,
77     int debug, int argc, char **argv)
78 {
79 	unsigned int		 proc, nargc, i, proc_i;
80 	char			**nargv;
81 	struct privsep_proc	*p;
82 	char			 num[32];
83 	int			 fd;
84 
85 	/* Prepare the new process argv. */
86 	nargv = calloc(argc + 5, sizeof(char *));
87 	if (nargv == NULL)
88 		fatal("%s: calloc", __func__);
89 
90 	/* Copy call argument first. */
91 	nargc = 0;
92 	nargv[nargc++] = argv[0];
93 
94 	/* Set process name argument and save the position. */
95 	nargv[nargc++] = "-P";
96 	proc_i = nargc;
97 	nargc++;
98 
99 	/* Point process instance arg to stack and copy the original args. */
100 	nargv[nargc++] = "-I";
101 	nargv[nargc++] = num;
102 	for (i = 1; i < (unsigned int) argc; i++)
103 		nargv[nargc++] = argv[i];
104 
105 	nargv[nargc] = NULL;
106 
107 	for (proc = 0; proc < nproc; proc++) {
108 		p = &procs[proc];
109 
110 		/* Update args with process title. */
111 		nargv[proc_i] = (char *)(uintptr_t)p->p_title;
112 
113 		/* Fire children processes. */
114 		for (i = 0; i < ps->ps_instances[p->p_id]; i++) {
115 			/* Update the process instance number. */
116 			snprintf(num, sizeof(num), "%u", i);
117 
118 			fd = ps->ps_pipes[p->p_id][i].pp_pipes[PROC_PARENT][0];
119 			ps->ps_pipes[p->p_id][i].pp_pipes[PROC_PARENT][0] = -1;
120 
121 			switch (fork()) {
122 			case -1:
123 				fatal("%s: fork", __func__);
124 				break;
125 			case 0:
126 				/* First create a new session */
127 				if (setsid() == -1)
128 					fatal("setsid");
129 
130 				/* Prepare parent socket. */
131 				if (fd != PROC_PARENT_SOCK_FILENO) {
132 					if (dup2(fd, PROC_PARENT_SOCK_FILENO)
133 					    == -1)
134 						fatal("dup2");
135 				} else if (fcntl(fd, F_SETFD, 0) == -1)
136 					fatal("fcntl");
137 
138 				/* Daemons detach from terminal. */
139 				if (!debug && (fd =
140 				    open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
141 					(void)dup2(fd, STDIN_FILENO);
142 					(void)dup2(fd, STDOUT_FILENO);
143 					(void)dup2(fd, STDERR_FILENO);
144 					if (fd > 2)
145 						(void)close(fd);
146 				}
147 
148 				execvp(argv[0], nargv);
149 				fatal("%s: execvp", __func__);
150 				break;
151 			default:
152 				/* Close child end. */
153 				close(fd);
154 				break;
155 			}
156 		}
157 	}
158 	free(nargv);
159 }
160 
161 void
162 proc_connect(struct privsep *ps)
163 {
164 	struct imsgev		*iev;
165 	unsigned int		 src, dst, inst;
166 
167 	/* Don't distribute any sockets if we are not really going to run. */
168 	if (ps->ps_noaction)
169 		return;
170 
171 	for (dst = 0; dst < PROC_MAX; dst++) {
172 		/* We don't communicate with ourselves. */
173 		if (dst == PROC_PARENT)
174 			continue;
175 
176 		for (inst = 0; inst < ps->ps_instances[dst]; inst++) {
177 			iev = &ps->ps_ievs[dst][inst];
178 			imsg_init(&iev->ibuf, ps->ps_pp->pp_pipes[dst][inst]);
179 			event_set(&iev->ev, iev->ibuf.fd, iev->events,
180 			    iev->handler, iev->data);
181 			event_add(&iev->ev, NULL);
182 		}
183 	}
184 
185 	/* Distribute the socketpair()s for everyone. */
186 	for (src = 0; src < PROC_MAX; src++)
187 		for (dst = src; dst < PROC_MAX; dst++) {
188 			/* Parent already distributed its fds. */
189 			if (src == PROC_PARENT || dst == PROC_PARENT)
190 				continue;
191 
192 			proc_open(ps, src, dst);
193 		}
194 }
195 
196 void
197 proc_init(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc,
198     int debug, int argc, char **argv, enum privsep_procid proc_id)
199 {
200 	struct privsep_proc	*p = NULL;
201 	struct privsep_pipes	*pa, *pb;
202 	unsigned int		 proc;
203 	unsigned int		 dst;
204 	int			 fds[2];
205 
206 	/* Don't initiate anything if we are not really going to run. */
207 	if (ps->ps_noaction)
208 		return;
209 
210 	if (proc_id == PROC_PARENT) {
211 		privsep_process = PROC_PARENT;
212 		proc_setup(ps, procs, nproc);
213 
214 		/*
215 		 * Create the children sockets so we can use them
216 		 * to distribute the rest of the socketpair()s using
217 		 * proc_connect() later.
218 		 */
219 		for (dst = 0; dst < PROC_MAX; dst++) {
220 			/* Don't create socket for ourselves. */
221 			if (dst == PROC_PARENT)
222 				continue;
223 
224 			for (proc = 0; proc < ps->ps_instances[dst]; proc++) {
225 				pa = &ps->ps_pipes[PROC_PARENT][0];
226 				pb = &ps->ps_pipes[dst][proc];
227 				if (socketpair(AF_UNIX,
228 				    SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
229 				    PF_UNSPEC, fds) == -1)
230 					fatal("%s: socketpair", __func__);
231 
232 				pa->pp_pipes[dst][proc] = fds[0];
233 				pb->pp_pipes[PROC_PARENT][0] = fds[1];
234 			}
235 		}
236 
237 		/* Engage! */
238 		proc_exec(ps, procs, nproc, debug, argc, argv);
239 		return;
240 	}
241 
242 	/* Initialize a child */
243 	for (proc = 0; proc < nproc; proc++) {
244 		if (procs[proc].p_id != proc_id)
245 			continue;
246 		p = &procs[proc];
247 		break;
248 	}
249 	if (p == NULL || p->p_init == NULL)
250 		fatalx("%s: process %d missing process initialization",
251 		    __func__, proc_id);
252 
253 	p->p_init(ps, p);
254 
255 	fatalx("failed to initiate child process");
256 }
257 
258 void
259 proc_accept(struct privsep *ps, int fd, enum privsep_procid dst,
260     unsigned int n)
261 {
262 	struct privsep_pipes	*pp = ps->ps_pp;
263 	struct imsgev		*iev;
264 
265 	if (ps->ps_ievs[dst] == NULL) {
266 #if DEBUG > 1
267 		log_debug("%s: %s src %d %d to dst %d %d not connected",
268 		    __func__, ps->ps_title[privsep_process],
269 		    privsep_process, ps->ps_instance + 1,
270 		    dst, n + 1);
271 #endif
272 		close(fd);
273 		return;
274 	}
275 
276 	if (pp->pp_pipes[dst][n] != -1) {
277 		log_warnx("%s: duplicated descriptor", __func__);
278 		close(fd);
279 		return;
280 	} else
281 		pp->pp_pipes[dst][n] = fd;
282 
283 	iev = &ps->ps_ievs[dst][n];
284 	imsg_init(&iev->ibuf, fd);
285 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
286 	event_add(&iev->ev, NULL);
287 }
288 
289 void
290 proc_setup(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc)
291 {
292 	unsigned int		 i, j, src, dst, id;
293 	struct privsep_pipes	*pp;
294 
295 	/* Initialize parent title, ps_instances and procs. */
296 	ps->ps_title[PROC_PARENT] = "parent";
297 
298 	for (src = 0; src < PROC_MAX; src++)
299 		/* Default to 1 process instance */
300 		if (ps->ps_instances[src] < 1)
301 			ps->ps_instances[src] = 1;
302 
303 	for (src = 0; src < nproc; src++) {
304 		procs[src].p_ps = ps;
305 		if (procs[src].p_cb == NULL)
306 			procs[src].p_cb = proc_dispatch_null;
307 
308 		id = procs[src].p_id;
309 		ps->ps_title[id] = procs[src].p_title;
310 		if ((ps->ps_ievs[id] = calloc(ps->ps_instances[id],
311 		    sizeof(struct imsgev))) == NULL)
312 			fatal("%s: calloc", __func__);
313 
314 		/* With this set up, we are ready to call imsg_init(). */
315 		for (i = 0; i < ps->ps_instances[id]; i++) {
316 			ps->ps_ievs[id][i].handler = proc_dispatch;
317 			ps->ps_ievs[id][i].events = EV_READ;
318 			ps->ps_ievs[id][i].proc = &procs[src];
319 			ps->ps_ievs[id][i].data = &ps->ps_ievs[id][i];
320 		}
321 	}
322 
323 	/*
324 	 * Allocate pipes for all process instances (incl. parent)
325 	 *
326 	 * - ps->ps_pipes: N:M mapping
327 	 * N source processes connected to M destination processes:
328 	 * [src][instances][dst][instances], for example
329 	 * [PROC_RELAY][3][PROC_CA][3]
330 	 *
331 	 * - ps->ps_pp: per-process 1:M part of ps->ps_pipes
332 	 * Each process instance has a destination array of socketpair fds:
333 	 * [dst][instances], for example
334 	 * [PROC_PARENT][0]
335 	 */
336 	for (src = 0; src < PROC_MAX; src++) {
337 		/* Allocate destination array for each process */
338 		if ((ps->ps_pipes[src] = calloc(ps->ps_instances[src],
339 		    sizeof(struct privsep_pipes))) == NULL)
340 			fatal("%s: calloc", __func__);
341 
342 		for (i = 0; i < ps->ps_instances[src]; i++) {
343 			pp = &ps->ps_pipes[src][i];
344 
345 			for (dst = 0; dst < PROC_MAX; dst++) {
346 				/* Allocate maximum fd integers */
347 				if ((pp->pp_pipes[dst] =
348 				    calloc(ps->ps_instances[dst],
349 				    sizeof(int))) == NULL)
350 					fatal("%s: calloc", __func__);
351 
352 				/* Mark fd as unused */
353 				for (j = 0; j < ps->ps_instances[dst]; j++)
354 					pp->pp_pipes[dst][j] = -1;
355 			}
356 		}
357 	}
358 
359 	ps->ps_pp = &ps->ps_pipes[privsep_process][ps->ps_instance];
360 }
361 
362 void
363 proc_kill(struct privsep *ps)
364 {
365 	char		*cause;
366 	pid_t		 pid;
367 	int		 len, status;
368 
369 	if (privsep_process != PROC_PARENT)
370 		return;
371 
372 	proc_close(ps);
373 
374 	do {
375 		pid = waitpid(WAIT_ANY, &status, 0);
376 		if (pid <= 0)
377 			continue;
378 
379 		if (WIFSIGNALED(status)) {
380 			len = asprintf(&cause, "terminated; signal %d",
381 			    WTERMSIG(status));
382 		} else if (WIFEXITED(status)) {
383 			if (WEXITSTATUS(status) != 0)
384 				len = asprintf(&cause, "exited abnormally");
385 			else
386 				len = 0;
387 		} else
388 			len = -1;
389 
390 		if (len == 0) {
391 			/* child exited OK, don't print a warning message */
392 		} else if (len != -1) {
393 			log_warnx("lost child: pid %u %s", pid, cause);
394 			free(cause);
395 		} else
396 			log_warnx("lost child: pid %u", pid);
397 	} while (pid != -1 || errno == EINTR);
398 }
399 
400 void
401 proc_open(struct privsep *ps, int src, int dst)
402 {
403 	struct privsep_pipes	*pa, *pb;
404 	struct privsep_fd	 pf;
405 	int			 fds[2];
406 	unsigned int		 i, j;
407 
408 	/* Exchange pipes between process. */
409 	for (i = 0; i < ps->ps_instances[src]; i++) {
410 		for (j = 0; j < ps->ps_instances[dst]; j++) {
411 			/* Don't create sockets for ourself. */
412 			if (src == dst && i == j)
413 				continue;
414 
415 			/* Proxies don't talk to each other. */
416 			if (src == PROC_PROXY && dst == PROC_PROXY)
417 				continue;
418 
419 			pa = &ps->ps_pipes[src][i];
420 			pb = &ps->ps_pipes[dst][j];
421 			if (socketpair(AF_UNIX,
422 			    SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
423 			    PF_UNSPEC, fds) == -1)
424 				fatal("%s: socketpair", __func__);
425 
426 			pa->pp_pipes[dst][j] = fds[0];
427 			pb->pp_pipes[src][i] = fds[1];
428 
429 			pf.pf_procid = src;
430 			pf.pf_instance = i;
431 			if (proc_compose_imsg(ps, dst, j, IMSG_CTL_PROCFD,
432 			    -1, pb->pp_pipes[src][i], &pf, sizeof(pf)) == -1)
433 				fatal("%s: proc_compose_imsg", __func__);
434 
435 			pf.pf_procid = dst;
436 			pf.pf_instance = j;
437 			if (proc_compose_imsg(ps, src, i, IMSG_CTL_PROCFD,
438 			    -1, pa->pp_pipes[dst][j], &pf, sizeof(pf)) == -1)
439 				fatal("%s: proc_compose_imsg", __func__);
440 
441 			/*
442 			 * We have to flush to send the descriptors and close
443 			 * them to avoid the fd ramp on startup.
444 			 */
445 			if (proc_flush_imsg(ps, src, i) == -1 ||
446 			    proc_flush_imsg(ps, dst, j) == -1)
447 				fatal("%s: imsg_flush", __func__);
448 		}
449 	}
450 }
451 
452 void
453 proc_close(struct privsep *ps)
454 {
455 	unsigned int		 dst, n;
456 	struct privsep_pipes	*pp;
457 
458 	if (ps == NULL)
459 		return;
460 
461 	pp = ps->ps_pp;
462 
463 	for (dst = 0; dst < PROC_MAX; dst++) {
464 		if (ps->ps_ievs[dst] == NULL)
465 			continue;
466 
467 		for (n = 0; n < ps->ps_instances[dst]; n++) {
468 			if (pp->pp_pipes[dst][n] == -1)
469 				continue;
470 
471 			/* Cancel the fd, close and invalidate the fd */
472 			event_del(&(ps->ps_ievs[dst][n].ev));
473 			imsg_clear(&(ps->ps_ievs[dst][n].ibuf));
474 			close(pp->pp_pipes[dst][n]);
475 			pp->pp_pipes[dst][n] = -1;
476 		}
477 		free(ps->ps_ievs[dst]);
478 	}
479 }
480 
481 void
482 proc_shutdown(struct privsep_proc *p)
483 {
484 	struct privsep	*ps = p->p_ps;
485 
486 	if (p->p_shutdown != NULL)
487 		(*p->p_shutdown)();
488 
489 	proc_close(ps);
490 
491 	log_info("%s exiting, pid %d", p->p_title, getpid());
492 
493 	exit(0);
494 }
495 
496 void
497 proc_sig_handler(int sig, short event, void *arg)
498 {
499 	struct privsep_proc	*p = arg;
500 
501 	switch (sig) {
502 	case SIGINT:
503 	case SIGTERM:
504 		proc_shutdown(p);
505 		break;
506 	case SIGCHLD:
507 	case SIGHUP:
508 		/* ignore */
509 		break;
510 	default:
511 		fatalx("%s: unexpected signal", __func__);
512 		/* NOTREACHED */
513 	}
514 }
515 
516 void
517 proc_run(struct privsep *ps, struct privsep_proc *p,
518     struct privsep_proc *procs, unsigned int nproc,
519     void (*run)(struct privsep *, struct privsep_proc *, void *), void *arg)
520 {
521 	struct passwd		*pw;
522 	const char		*root;
523 
524 	log_procinit(p->p_title);
525 
526 	/* Set the process group of the current process */
527 	setpgid(0, 0);
528 
529 	/* Use non-standard user */
530 	if (p->p_pw != NULL)
531 		pw = p->p_pw;
532 	else
533 		pw = ps->ps_pw;
534 
535 	/* Change root directory */
536 	if (p->p_chroot != NULL)
537 		root = p->p_chroot;
538 	else
539 		root = pw->pw_dir;
540 
541 	if (chroot(root) == -1)
542 		fatal("%s: chroot", __func__);
543 	if (chdir("/") == -1)
544 		fatal("%s: chdir(\"/\")", __func__);
545 
546 	privsep_process = p->p_id;
547 
548 	setproctitle("%s", p->p_title);
549 
550 	if (setgroups(1, &pw->pw_gid) ||
551 	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
552 	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
553 		fatal("%s: cannot drop privileges", __func__);
554 
555 	event_init();
556 
557 	signal(SIGPIPE, SIG_IGN);
558 
559 	signal_set(&ps->ps_evsigint, SIGINT, proc_sig_handler, p);
560 	signal_set(&ps->ps_evsigterm, SIGTERM, proc_sig_handler, p);
561 	signal_set(&ps->ps_evsigchld, SIGCHLD, proc_sig_handler, p);
562 	signal_set(&ps->ps_evsighup, SIGHUP, proc_sig_handler, p);
563 
564 	signal_add(&ps->ps_evsigint, NULL);
565 	signal_add(&ps->ps_evsigterm, NULL);
566 	signal_add(&ps->ps_evsigchld, NULL);
567 	signal_add(&ps->ps_evsighup, NULL);
568 
569 	proc_setup(ps, procs, nproc);
570 	proc_accept(ps, PROC_PARENT_SOCK_FILENO, PROC_PARENT, 0);
571 
572 	log_debug("%s: %s %d/%d, pid %d", __func__, p->p_title,
573 	    ps->ps_instance + 1, ps->ps_instances[p->p_id], getpid());
574 
575 	if (run != NULL)
576 		run(ps, p, arg);
577 
578 	event_dispatch();
579 
580 	proc_shutdown(p);
581 }
582 
583 void
584 proc_dispatch(int fd, short event, void *arg)
585 {
586 	struct imsgev		*iev = arg;
587 	struct privsep_proc	*p = iev->proc;
588 	struct privsep		*ps = p->p_ps;
589 	struct imsgbuf		*ibuf;
590 	struct imsg		 imsg;
591 	ssize_t			 n;
592 	const char		*title;
593 	struct privsep_fd	 pf;
594 
595 	title = ps->ps_title[privsep_process];
596 	ibuf = &iev->ibuf;
597 
598 	if (event & EV_READ) {
599 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
600 			fatal("%s: imsg_read", __func__);
601 		if (n == 0) {
602 			/* this pipe is dead, so remove the event handler */
603 			event_del(&iev->ev);
604 			event_loopexit(NULL);
605 			return;
606 		}
607 	}
608 
609 	if (event & EV_WRITE) {
610 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
611 			fatal("%s: msgbuf_write", __func__);
612 		if (n == 0) {
613 			/* this pipe is dead, so remove the event handler */
614 			event_del(&iev->ev);
615 			event_loopexit(NULL);
616 			return;
617 		}
618 	}
619 
620 	for (;;) {
621 		if ((n = imsg_get(ibuf, &imsg)) == -1)
622 			fatal("%s: imsg_get", __func__);
623 		if (n == 0)
624 			break;
625 
626 #if DEBUG > 1
627 		log_debug("%s: %s %d got imsg %d peerid %d from %s %d",
628 		    __func__, title, ps->ps_instance + 1,
629 		    imsg.hdr.type, imsg.hdr.peerid, p->p_title, imsg.hdr.pid);
630 #endif
631 
632 		/*
633 		 * Check the message with the program callback
634 		 */
635 		if ((p->p_cb)(fd, p, &imsg) == 0) {
636 			/* Message was handled by the callback, continue */
637 			imsg_free(&imsg);
638 			continue;
639 		}
640 
641 		/*
642 		 * Generic message handling
643 		 */
644 		switch (imsg.hdr.type) {
645 		case IMSG_CTL_PROCFD:
646 			IMSG_SIZE_CHECK(&imsg, &pf);
647 			memcpy(&pf, imsg.data, sizeof(pf));
648 			proc_accept(ps, imsg.fd, pf.pf_procid,
649 			    pf.pf_instance);
650 			break;
651 		default:
652 			fatalx("%s: %s %d got invalid imsg %d peerid %d "
653 			    "from %s %d",
654 			    __func__, title, ps->ps_instance + 1,
655 			    imsg.hdr.type, imsg.hdr.peerid,
656 			    p->p_title, imsg.hdr.pid);
657 		}
658 		imsg_free(&imsg);
659 	}
660 	imsg_event_add(iev);
661 }
662 
663 int
664 proc_dispatch_null(int fd, struct privsep_proc *p, struct imsg *imsg)
665 {
666 	return (-1);
667 }
668 
669 /*
670  * imsg helper functions
671  */
672 
673 void
674 imsg_event_add(struct imsgev *iev)
675 {
676 	if (iev->handler == NULL) {
677 		imsg_flush(&iev->ibuf);
678 		return;
679 	}
680 
681 	iev->events = EV_READ;
682 	if (iev->ibuf.w.queued)
683 		iev->events |= EV_WRITE;
684 
685 	event_del(&iev->ev);
686 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
687 	event_add(&iev->ev, NULL);
688 }
689 
690 int
691 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
692     pid_t pid, int fd, void *data, uint16_t datalen)
693 {
694 	int	ret;
695 
696 	if ((ret = imsg_compose(&iev->ibuf, type, peerid,
697 	    pid, fd, data, datalen)) == -1)
698 		return (ret);
699 	imsg_event_add(iev);
700 	return (ret);
701 }
702 
703 int
704 imsg_composev_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
705     pid_t pid, int fd, const struct iovec *iov, int iovcnt)
706 {
707 	int	ret;
708 
709 	if ((ret = imsg_composev(&iev->ibuf, type, peerid,
710 	    pid, fd, iov, iovcnt)) == -1)
711 		return (ret);
712 	imsg_event_add(iev);
713 	return (ret);
714 }
715 
716 void
717 proc_range(struct privsep *ps, enum privsep_procid id, int *n, int *m)
718 {
719 	if (*n == -1) {
720 		/* Use a range of all target instances */
721 		*n = 0;
722 		*m = ps->ps_instances[id];
723 	} else {
724 		/* Use only a single slot of the specified peer process */
725 		*m = *n + 1;
726 	}
727 }
728 
729 int
730 proc_compose_imsg(struct privsep *ps, enum privsep_procid id, int n,
731     uint16_t type, uint32_t peerid, int fd, void *data, uint16_t datalen)
732 {
733 	int	 m;
734 
735 	proc_range(ps, id, &n, &m);
736 	for (; n < m; n++) {
737 		if (imsg_compose_event(&ps->ps_ievs[id][n],
738 		    type, peerid, ps->ps_instance + 1, fd, data, datalen) == -1)
739 			return (-1);
740 	}
741 
742 	return (0);
743 }
744 
745 int
746 proc_compose(struct privsep *ps, enum privsep_procid id,
747     uint16_t type, void *data, uint16_t datalen)
748 {
749 	return (proc_compose_imsg(ps, id, -1, type, -1, -1, data, datalen));
750 }
751 
752 int
753 proc_composev_imsg(struct privsep *ps, enum privsep_procid id, int n,
754     uint16_t type, uint32_t peerid, int fd, const struct iovec *iov, int iovcnt)
755 {
756 	int	 m;
757 
758 	proc_range(ps, id, &n, &m);
759 	for (; n < m; n++)
760 		if (imsg_composev_event(&ps->ps_ievs[id][n],
761 		    type, peerid, ps->ps_instance + 1, fd, iov, iovcnt) == -1)
762 			return (-1);
763 
764 	return (0);
765 }
766 
767 int
768 proc_composev(struct privsep *ps, enum privsep_procid id,
769     uint16_t type, const struct iovec *iov, int iovcnt)
770 {
771 	return (proc_composev_imsg(ps, id, -1, type, -1, -1, iov, iovcnt));
772 }
773 
774 int
775 proc_forward_imsg(struct privsep *ps, struct imsg *imsg,
776     enum privsep_procid id, int n)
777 {
778 	return (proc_compose_imsg(ps, id, n, imsg->hdr.type,
779 	    imsg->hdr.peerid, imsg->fd, imsg->data, IMSG_DATA_SIZE(imsg)));
780 }
781 
782 struct imsgbuf *
783 proc_ibuf(struct privsep *ps, enum privsep_procid id, int n)
784 {
785 	int	 m;
786 
787 	proc_range(ps, id, &n, &m);
788 	return (&ps->ps_ievs[id][n].ibuf);
789 }
790 
791 struct imsgev *
792 proc_iev(struct privsep *ps, enum privsep_procid id, int n)
793 {
794 	int	 m;
795 
796 	proc_range(ps, id, &n, &m);
797 	return (&ps->ps_ievs[id][n]);
798 }
799 
800 /* This function should only be called with care as it breaks async I/O */
801 int
802 proc_flush_imsg(struct privsep *ps, enum privsep_procid id, int n)
803 {
804 	struct imsgbuf	*ibuf;
805 	int		 m, ret = 0;
806 
807 	proc_range(ps, id, &n, &m);
808 	for (; n < m; n++) {
809 		if ((ibuf = proc_ibuf(ps, id, n)) == NULL)
810 			return (-1);
811 		do {
812 			ret = imsg_flush(ibuf);
813 		} while (ret == -1 && errno == EAGAIN);
814 		if (ret == -1)
815 			break;
816 		imsg_event_add(&ps->ps_ievs[id][n]);
817 	}
818 
819 	return (ret);
820 }