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