xref: /openbsd-src/usr.sbin/snmpd/proc.c (revision 6676295ff107abd6850f48ae428e19963f4b1dc5)
1 /*	$OpenBSD: proc.c,v 1.39 2024/11/21 13:38:45 claudio 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/socket.h>
21 #include <sys/wait.h>
22 
23 #include <fcntl.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <stdint.h>
27 #include <unistd.h>
28 #include <string.h>
29 #include <errno.h>
30 #include <signal.h>
31 #include <paths.h>
32 #include <pwd.h>
33 #include <event.h>
34 #include <imsg.h>
35 
36 #include "log.h"
37 #include "snmpd.h"
38 
39 void	 proc_exec(struct privsep *, struct privsep_proc *, unsigned int, int,
40 	    char **);
41 void	 proc_setup(struct privsep *, struct privsep_proc *, unsigned int);
42 void	 proc_open(struct privsep *, int, int);
43 void	 proc_accept(struct privsep *, int, enum privsep_procid,
44 	    unsigned int);
45 void	 proc_close(struct privsep *);
46 void	 proc_shutdown(struct privsep_proc *);
47 void	 proc_sig_handler(int, short, void *);
48 void	 proc_range(struct privsep *, enum privsep_procid, int *, int *);
49 int	 proc_dispatch_null(int, struct privsep_proc *, struct imsg *);
50 
51 enum privsep_procid
52 proc_getid(struct privsep_proc *procs, unsigned int nproc,
53     const char *proc_name)
54 {
55 	struct privsep_proc	*p;
56 	unsigned int		 proc;
57 
58 	for (proc = 0; proc < nproc; proc++) {
59 		p = &procs[proc];
60 		if (strcmp(p->p_title, proc_name))
61 			continue;
62 
63 		return (p->p_id);
64 	}
65 
66 	return (PROC_MAX);
67 }
68 
69 void
70 proc_exec(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc,
71     int argc, char **argv)
72 {
73 	unsigned int		 proc, nargc, i, proc_i;
74 	char			**nargv;
75 	struct privsep_proc	*p;
76 	char			 num[32];
77 	int			 fd;
78 
79 	/* Prepare the new process argv. */
80 	nargv = calloc(argc + 5, sizeof(char *));
81 	if (nargv == NULL)
82 		fatal("%s: calloc", __func__);
83 
84 	/* Copy call argument first. */
85 	nargc = 0;
86 	nargv[nargc++] = argv[0];
87 
88 	/* Set process name argument and save the position. */
89 	nargv[nargc++] = "-P";
90 	proc_i = nargc;
91 	nargc++;
92 
93 	/* Point process instance arg to stack and copy the original args. */
94 	nargv[nargc++] = "-I";
95 	nargv[nargc++] = num;
96 	for (i = 1; i < (unsigned int) argc; i++)
97 		nargv[nargc++] = argv[i];
98 
99 	nargv[nargc] = NULL;
100 
101 	for (proc = 0; proc < nproc; proc++) {
102 		p = &procs[proc];
103 
104 		/* Update args with process title. */
105 		nargv[proc_i] = (char *)(uintptr_t)p->p_title;
106 
107 		/* Fire children processes. */
108 		for (i = 0; i < ps->ps_instances[p->p_id]; i++) {
109 			/* Update the process instance number. */
110 			snprintf(num, sizeof(num), "%u", i);
111 
112 			fd = ps->ps_pipes[p->p_id][i].pp_pipes[PROC_PARENT][0];
113 			ps->ps_pipes[p->p_id][i].pp_pipes[PROC_PARENT][0] = -1;
114 
115 			switch (fork()) {
116 			case -1:
117 				fatal("%s: fork", __func__);
118 				break;
119 			case 0:
120 				/* Prepare parent socket. */
121 				if (fd != PROC_PARENT_SOCK_FILENO) {
122 					if (dup2(fd, PROC_PARENT_SOCK_FILENO)
123 					    == -1)
124 						fatal("dup2");
125 				} else if (fcntl(fd, F_SETFD, 0) == -1)
126 					fatal("fcntl");
127 
128 				execvp(argv[0], nargv);
129 				fatal("%s: execvp", __func__);
130 				break;
131 			default:
132 				/* Close child end. */
133 				close(fd);
134 				break;
135 			}
136 		}
137 	}
138 	free(nargv);
139 }
140 
141 void
142 proc_connect(struct privsep *ps)
143 {
144 	struct imsgev		*iev;
145 	unsigned int		 src, dst, inst;
146 
147 	/* Don't distribute any sockets if we are not really going to run. */
148 	if (ps->ps_noaction)
149 		return;
150 
151 	for (dst = 0; dst < PROC_MAX; dst++) {
152 		/* We don't communicate with ourselves. */
153 		if (dst == PROC_PARENT)
154 			continue;
155 
156 		for (inst = 0; inst < ps->ps_instances[dst]; inst++) {
157 			iev = &ps->ps_ievs[dst][inst];
158 			if (imsgbuf_init(&iev->ibuf,
159 			    ps->ps_pp->pp_pipes[dst][inst]) == -1)
160 				fatal("imsgbuf_init");
161 			imsgbuf_allow_fdpass(&iev->ibuf);
162 			event_set(&iev->ev, iev->ibuf.fd, iev->events,
163 			    iev->handler, iev->data);
164 			event_add(&iev->ev, NULL);
165 		}
166 	}
167 
168 	/* Distribute the socketpair()s for everyone. */
169 	for (src = 0; src < PROC_MAX; src++)
170 		for (dst = src; dst < PROC_MAX; dst++) {
171 			/* Parent already distributed its fds. */
172 			if (src == PROC_PARENT || dst == PROC_PARENT)
173 				continue;
174 
175 			proc_open(ps, src, dst);
176 		}
177 }
178 
179 void
180 proc_init(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc,
181     int debug, int argc, char **argv, enum privsep_procid proc_id)
182 {
183 	struct privsep_proc	*p = NULL;
184 	struct privsep_pipes	*pa, *pb;
185 	unsigned int		 proc;
186 	unsigned int		 dst;
187 	int			 fds[2];
188 
189 	/* Don't initiate anything if we are not really going to run. */
190 	if (ps->ps_noaction)
191 		return;
192 
193 	if (proc_id == PROC_PARENT) {
194 		privsep_process = PROC_PARENT;
195 		proc_setup(ps, procs, nproc);
196 
197 		if (!debug && daemon(0, 0) == -1)
198 			fatal("failed to daemonize");
199 
200 		/*
201 		 * Create the children sockets so we can use them
202 		 * to distribute the rest of the socketpair()s using
203 		 * proc_connect() later.
204 		 */
205 		for (dst = 0; dst < PROC_MAX; dst++) {
206 			/* Don't create socket for ourselves. */
207 			if (dst == PROC_PARENT)
208 				continue;
209 
210 			for (proc = 0; proc < ps->ps_instances[dst]; proc++) {
211 				pa = &ps->ps_pipes[PROC_PARENT][0];
212 				pb = &ps->ps_pipes[dst][proc];
213 				if (socketpair(AF_UNIX,
214 				    SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
215 				    PF_UNSPEC, fds) == -1)
216 					fatal("%s: socketpair", __func__);
217 
218 				pa->pp_pipes[dst][proc] = fds[0];
219 				pb->pp_pipes[PROC_PARENT][0] = fds[1];
220 			}
221 		}
222 
223 		/* Engage! */
224 		proc_exec(ps, procs, nproc, argc, argv);
225 		return;
226 	}
227 
228 	/* Initialize a child */
229 	for (proc = 0; proc < nproc; proc++) {
230 		if (procs[proc].p_id != proc_id)
231 			continue;
232 		p = &procs[proc];
233 		break;
234 	}
235 	if (p == NULL || p->p_init == NULL)
236 		fatalx("%s: process %d missing process initialization",
237 		    __func__, proc_id);
238 
239 	p->p_init(ps, p);
240 
241 	fatalx("failed to initiate child process");
242 }
243 
244 void
245 proc_accept(struct privsep *ps, int fd, enum privsep_procid dst,
246     unsigned int n)
247 {
248 	struct privsep_pipes	*pp = ps->ps_pp;
249 	struct imsgev		*iev;
250 
251 	if (ps->ps_ievs[dst] == NULL) {
252 #if DEBUG > 1
253 		log_debug("%s: %s src %d %d to dst %d %d not connected",
254 		    __func__, ps->ps_title[privsep_process],
255 		    privsep_process, ps->ps_instance + 1,
256 		    dst, n + 1);
257 #endif
258 		close(fd);
259 		return;
260 	}
261 
262 	if (pp->pp_pipes[dst][n] != -1) {
263 		log_warnx("%s: duplicated descriptor", __func__);
264 		close(fd);
265 		return;
266 	} else
267 		pp->pp_pipes[dst][n] = fd;
268 
269 	iev = &ps->ps_ievs[dst][n];
270 	if (imsgbuf_init(&iev->ibuf, fd) == -1)
271 		fatal("imsgbuf_init");
272 	imsgbuf_allow_fdpass(&iev->ibuf);
273 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
274 	event_add(&iev->ev, NULL);
275 }
276 
277 void
278 proc_setup(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc)
279 {
280 	unsigned int		 i, j, src, dst, id;
281 	struct privsep_pipes	*pp;
282 
283 	/* Initialize parent title, ps_instances and procs. */
284 	ps->ps_title[PROC_PARENT] = "parent";
285 
286 	for (src = 0; src < PROC_MAX; src++)
287 		/* Default to 1 process instance */
288 		if (ps->ps_instances[src] < 1)
289 			ps->ps_instances[src] = 1;
290 
291 	for (src = 0; src < nproc; src++) {
292 		procs[src].p_ps = ps;
293 		if (procs[src].p_cb == NULL)
294 			procs[src].p_cb = proc_dispatch_null;
295 
296 		id = procs[src].p_id;
297 		ps->ps_title[id] = procs[src].p_title;
298 		if ((ps->ps_ievs[id] = calloc(ps->ps_instances[id],
299 		    sizeof(struct imsgev))) == NULL)
300 			fatal("%s: calloc", __func__);
301 
302 		/* With this set up, we are ready to call imsgbuf_init(). */
303 		for (i = 0; i < ps->ps_instances[id]; i++) {
304 			ps->ps_ievs[id][i].handler = proc_dispatch;
305 			ps->ps_ievs[id][i].events = EV_READ;
306 			ps->ps_ievs[id][i].proc = &procs[src];
307 			ps->ps_ievs[id][i].data = &ps->ps_ievs[id][i];
308 		}
309 	}
310 
311 	/*
312 	 * Allocate pipes for all process instances (incl. parent)
313 	 *
314 	 * - ps->ps_pipes: N:M mapping
315 	 * N source processes connected to M destination processes:
316 	 * [src][instances][dst][instances], for example
317 	 * [PROC_RELAY][3][PROC_CA][3]
318 	 *
319 	 * - ps->ps_pp: per-process 1:M part of ps->ps_pipes
320 	 * Each process instance has a destination array of socketpair fds:
321 	 * [dst][instances], for example
322 	 * [PROC_PARENT][0]
323 	 */
324 	for (src = 0; src < PROC_MAX; src++) {
325 		/* Allocate destination array for each process */
326 		if ((ps->ps_pipes[src] = calloc(ps->ps_instances[src],
327 		    sizeof(struct privsep_pipes))) == NULL)
328 			fatal("%s: calloc", __func__);
329 
330 		for (i = 0; i < ps->ps_instances[src]; i++) {
331 			pp = &ps->ps_pipes[src][i];
332 
333 			for (dst = 0; dst < PROC_MAX; dst++) {
334 				/* Allocate maximum fd integers */
335 				if ((pp->pp_pipes[dst] =
336 				    calloc(ps->ps_instances[dst],
337 				    sizeof(int))) == NULL)
338 					fatal("%s: calloc", __func__);
339 
340 				/* Mark fd as unused */
341 				for (j = 0; j < ps->ps_instances[dst]; j++)
342 					pp->pp_pipes[dst][j] = -1;
343 			}
344 		}
345 	}
346 
347 	ps->ps_pp = &ps->ps_pipes[privsep_process][ps->ps_instance];
348 }
349 
350 void
351 proc_kill(struct privsep *ps)
352 {
353 	char		*cause;
354 	pid_t		 pid;
355 	int		 len, status;
356 
357 	if (privsep_process != PROC_PARENT)
358 		return;
359 
360 	proc_close(ps);
361 
362 	do {
363 		pid = waitpid(WAIT_ANY, &status, 0);
364 		if (pid <= 0)
365 			continue;
366 
367 		if (WIFSIGNALED(status)) {
368 			len = asprintf(&cause, "terminated; signal %d",
369 			    WTERMSIG(status));
370 		} else if (WIFEXITED(status)) {
371 			if (WEXITSTATUS(status) != 0)
372 				len = asprintf(&cause, "exited abnormally");
373 			else
374 				len = 0;
375 		} else
376 			len = -1;
377 
378 		if (len == 0) {
379 			/* child exited OK, don't print a warning message */
380 		} else if (len != -1) {
381 			log_warnx("lost child: pid %u %s", pid, cause);
382 			free(cause);
383 		} else
384 			log_warnx("lost child: pid %u", pid);
385 	} while (pid != -1 || (pid == -1 && errno == EINTR));
386 }
387 
388 void
389 proc_open(struct privsep *ps, int src, int dst)
390 {
391 	struct privsep_pipes	*pa, *pb;
392 	struct privsep_fd	 pf;
393 	int			 fds[2];
394 	unsigned int		 i, j;
395 
396 	/* Exchange pipes between process. */
397 	for (i = 0; i < ps->ps_instances[src]; i++) {
398 		for (j = 0; j < ps->ps_instances[dst]; j++) {
399 			/* Don't create sockets for ourself. */
400 			if (src == dst && i == j)
401 				continue;
402 
403 			pa = &ps->ps_pipes[src][i];
404 			pb = &ps->ps_pipes[dst][j];
405 			if (socketpair(AF_UNIX,
406 			    SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
407 			    PF_UNSPEC, fds) == -1)
408 				fatal("%s: socketpair", __func__);
409 
410 			pa->pp_pipes[dst][j] = fds[0];
411 			pb->pp_pipes[src][i] = fds[1];
412 
413 			pf.pf_procid = src;
414 			pf.pf_instance = i;
415 			if (proc_compose_imsg(ps, dst, j, IMSG_CTL_PROCFD,
416 			    -1, pb->pp_pipes[src][i], &pf, sizeof(pf)) == -1)
417 				fatal("%s: proc_compose_imsg", __func__);
418 
419 			pf.pf_procid = dst;
420 			pf.pf_instance = j;
421 			if (proc_compose_imsg(ps, src, i, IMSG_CTL_PROCFD,
422 			    -1, pa->pp_pipes[dst][j], &pf, sizeof(pf)) == -1)
423 				fatal("%s: proc_compose_imsg", __func__);
424 
425 			/*
426 			 * We have to flush to send the descriptors and close
427 			 * them to avoid the fd ramp on startup.
428 			 */
429 			if (proc_flush_imsg(ps, src, i) == -1 ||
430 			    proc_flush_imsg(ps, dst, j) == -1)
431 				fatal("%s: proc_flush_imsg", __func__);
432 		}
433 	}
434 }
435 
436 void
437 proc_close(struct privsep *ps)
438 {
439 	unsigned int		 dst, n;
440 	struct privsep_pipes	*pp;
441 
442 	if (ps == NULL)
443 		return;
444 
445 	pp = ps->ps_pp;
446 
447 	for (dst = 0; dst < PROC_MAX; dst++) {
448 		if (ps->ps_ievs[dst] == NULL)
449 			continue;
450 
451 		for (n = 0; n < ps->ps_instances[dst]; n++) {
452 			if (pp->pp_pipes[dst][n] == -1)
453 				continue;
454 
455 			/* Cancel the fd, close and invalidate the fd */
456 			event_del(&(ps->ps_ievs[dst][n].ev));
457 			imsgbuf_clear(&(ps->ps_ievs[dst][n].ibuf));
458 			close(pp->pp_pipes[dst][n]);
459 			pp->pp_pipes[dst][n] = -1;
460 		}
461 		free(ps->ps_ievs[dst]);
462 	}
463 }
464 
465 void
466 proc_shutdown(struct privsep_proc *p)
467 {
468 	struct privsep	*ps = p->p_ps;
469 
470 	if (p->p_shutdown != NULL)
471 		(*p->p_shutdown)();
472 
473 	proc_close(ps);
474 
475 	log_info("%s exiting, pid %d", p->p_title, getpid());
476 
477 	exit(0);
478 }
479 
480 void
481 proc_sig_handler(int sig, short event, void *arg)
482 {
483 	struct privsep_proc	*p = arg;
484 
485 	switch (sig) {
486 	case SIGINT:
487 	case SIGTERM:
488 		proc_shutdown(p);
489 		break;
490 	case SIGCHLD:
491 	case SIGHUP:
492 	case SIGPIPE:
493 	case SIGUSR1:
494 		/* ignore */
495 		break;
496 	default:
497 		fatalx("%s: unexpected signal", __func__);
498 		/* NOTREACHED */
499 	}
500 }
501 
502 void
503 proc_run(struct privsep *ps, struct privsep_proc *p,
504     struct privsep_proc *procs, unsigned int nproc,
505     void (*run)(struct privsep *, struct privsep_proc *, void *), void *arg)
506 {
507 	struct passwd		*pw;
508 	const char		*root;
509 
510 	log_procinit(p->p_title);
511 
512 	/* Use non-standard user */
513 	if (p->p_pw != NULL)
514 		pw = p->p_pw;
515 	else
516 		pw = ps->ps_pw;
517 
518 	/* Change root directory */
519 	if (p->p_chroot != NULL)
520 		root = p->p_chroot;
521 	else
522 		root = pw->pw_dir;
523 
524 	if (chroot(root) == -1)
525 		fatal("%s: chroot", __func__);
526 	if (chdir("/") == -1)
527 		fatal("%s: chdir(\"/\")", __func__);
528 
529 	privsep_process = p->p_id;
530 
531 	setproctitle("%s", p->p_title);
532 
533 	if (setgroups(1, &pw->pw_gid) ||
534 	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
535 	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
536 		fatal("%s: cannot drop privileges", __func__);
537 
538 	event_init();
539 
540 	signal_set(&ps->ps_evsigint, SIGINT, proc_sig_handler, p);
541 	signal_set(&ps->ps_evsigterm, SIGTERM, proc_sig_handler, p);
542 	signal_set(&ps->ps_evsigchld, SIGCHLD, proc_sig_handler, p);
543 	signal_set(&ps->ps_evsighup, SIGHUP, proc_sig_handler, p);
544 	signal_set(&ps->ps_evsigpipe, SIGPIPE, proc_sig_handler, p);
545 	signal_set(&ps->ps_evsigusr1, SIGUSR1, proc_sig_handler, p);
546 
547 	signal_add(&ps->ps_evsigint, NULL);
548 	signal_add(&ps->ps_evsigterm, NULL);
549 	signal_add(&ps->ps_evsigchld, NULL);
550 	signal_add(&ps->ps_evsighup, NULL);
551 	signal_add(&ps->ps_evsigpipe, NULL);
552 	signal_add(&ps->ps_evsigusr1, NULL);
553 
554 	proc_setup(ps, procs, nproc);
555 	proc_accept(ps, PROC_PARENT_SOCK_FILENO, PROC_PARENT, 0);
556 	DPRINTF("%s: %s %d/%d, pid %d", __func__, p->p_title,
557 	    ps->ps_instance + 1, ps->ps_instances[p->p_id], getpid());
558 
559 	if (run != NULL)
560 		run(ps, p, arg);
561 
562 	event_dispatch();
563 
564 	proc_shutdown(p);
565 }
566 
567 void
568 proc_dispatch(int fd, short event, void *arg)
569 {
570 	struct imsgev		*iev = arg;
571 	struct privsep_proc	*p = iev->proc;
572 	struct privsep		*ps = p->p_ps;
573 	struct imsgbuf		*ibuf;
574 	struct imsg		 imsg;
575 	ssize_t			 n;
576 	int			 verbose;
577 	const char		*title;
578 	struct privsep_fd	 pf;
579 
580 	title = ps->ps_title[privsep_process];
581 	ibuf = &iev->ibuf;
582 
583 	if (event & EV_READ) {
584 		if ((n = imsgbuf_read(ibuf)) == -1)
585 			fatal("%s: imsgbuf_read", __func__);
586 		if (n == 0) {
587 			/* this pipe is dead, so remove the event handler */
588 			event_del(&iev->ev);
589 			event_loopexit(NULL);
590 			return;
591 		}
592 	}
593 
594 	if (event & EV_WRITE) {
595 		if (imsgbuf_write(ibuf) == -1) {
596 			if (errno == EPIPE) {
597 				/* this pipe is dead, remove the handler */
598 				event_del(&iev->ev);
599 				event_loopexit(NULL);
600 				return;
601 			}
602 			fatal("%s: imsgbuf_write", __func__);
603 		}
604 	}
605 
606 	for (;;) {
607 		if ((n = imsg_get(ibuf, &imsg)) == -1)
608 			fatal("%s: imsg_get", __func__);
609 		if (n == 0)
610 			break;
611 
612 #if DEBUG > 1
613 		log_debug("%s: %s %d got imsg %d peerid %d from %s %d",
614 		    __func__, title, ps->ps_instance + 1,
615 		    imsg.hdr.type, imsg.hdr.peerid, p->p_title, imsg.hdr.pid);
616 #endif
617 
618 		/*
619 		 * Check the message with the program callback
620 		 */
621 		if ((p->p_cb)(fd, p, &imsg) == 0) {
622 			/* Message was handled by the callback, continue */
623 			imsg_free(&imsg);
624 			continue;
625 		}
626 
627 		/*
628 		 * Generic message handling
629 		 */
630 		switch (imsg.hdr.type) {
631 		case IMSG_CTL_VERBOSE:
632 			IMSG_SIZE_CHECK(&imsg, &verbose);
633 			memcpy(&verbose, imsg.data, sizeof(verbose));
634 			log_setverbose(verbose);
635 			break;
636 		case IMSG_CTL_PROCFD:
637 			IMSG_SIZE_CHECK(&imsg, &pf);
638 			memcpy(&pf, imsg.data, sizeof(pf));
639 			proc_accept(ps, imsg_get_fd(&imsg), pf.pf_procid,
640 			    pf.pf_instance);
641 			break;
642 		default:
643 			fatalx("%s: %s %d got invalid imsg %d peerid %d "
644 			    "from %s %d",
645 			    __func__, title, ps->ps_instance + 1,
646 			    imsg.hdr.type, imsg.hdr.peerid,
647 			    p->p_title, imsg.hdr.pid);
648 		}
649 		imsg_free(&imsg);
650 	}
651 	imsg_event_add(iev);
652 }
653 
654 int
655 proc_dispatch_null(int fd, struct privsep_proc *p, struct imsg *imsg)
656 {
657 	return (-1);
658 }
659 
660 /*
661  * imsg helper functions
662  */
663 
664 void
665 imsg_event_add(struct imsgev *iev)
666 {
667 	if (iev->handler == NULL) {
668 		imsgbuf_flush(&iev->ibuf);
669 		return;
670 	}
671 
672 	iev->events = EV_READ;
673 	if (imsgbuf_queuelen(&iev->ibuf) > 0)
674 		iev->events |= EV_WRITE;
675 
676 	event_del(&iev->ev);
677 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
678 	event_add(&iev->ev, NULL);
679 }
680 
681 int
682 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
683     pid_t pid, int fd, void *data, uint16_t datalen)
684 {
685 	int	ret;
686 
687 	if ((ret = imsg_compose(&iev->ibuf, type, peerid,
688 	    pid, fd, data, datalen)) == -1)
689 		return (ret);
690 	imsg_event_add(iev);
691 	return (ret);
692 }
693 
694 int
695 imsg_composev_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
696     pid_t pid, int fd, const struct iovec *iov, int iovcnt)
697 {
698 	int	ret;
699 
700 	if ((ret = imsg_composev(&iev->ibuf, type, peerid,
701 	    pid, fd, iov, iovcnt)) == -1)
702 		return (ret);
703 	imsg_event_add(iev);
704 	return (ret);
705 }
706 
707 void
708 proc_range(struct privsep *ps, enum privsep_procid id, int *n, int *m)
709 {
710 	if (*n == -1) {
711 		/* Use a range of all target instances */
712 		*n = 0;
713 		*m = ps->ps_instances[id];
714 	} else {
715 		/* Use only a single slot of the specified peer process */
716 		*m = *n + 1;
717 	}
718 }
719 
720 int
721 proc_compose_imsg(struct privsep *ps, enum privsep_procid id, int n,
722     uint16_t type, uint32_t peerid, int fd, void *data, uint16_t datalen)
723 {
724 	int	 m;
725 
726 	proc_range(ps, id, &n, &m);
727 	for (; n < m; n++) {
728 		if (imsg_compose_event(&ps->ps_ievs[id][n],
729 		    type, peerid, ps->ps_instance + 1, fd, data, datalen) == -1)
730 			return (-1);
731 	}
732 
733 	return (0);
734 }
735 
736 int
737 proc_compose(struct privsep *ps, enum privsep_procid id,
738     uint16_t type, void *data, uint16_t datalen)
739 {
740 	return (proc_compose_imsg(ps, id, -1, type, -1, -1, data, datalen));
741 }
742 
743 int
744 proc_composev_imsg(struct privsep *ps, enum privsep_procid id, int n,
745     uint16_t type, uint32_t peerid, int fd, const struct iovec *iov, int iovcnt)
746 {
747 	int	 m;
748 
749 	proc_range(ps, id, &n, &m);
750 	for (; n < m; n++)
751 		if (imsg_composev_event(&ps->ps_ievs[id][n],
752 		    type, peerid, ps->ps_instance + 1, fd, iov, iovcnt) == -1)
753 			return (-1);
754 
755 	return (0);
756 }
757 
758 int
759 proc_composev(struct privsep *ps, enum privsep_procid id,
760     uint16_t type, const struct iovec *iov, int iovcnt)
761 {
762 	return (proc_composev_imsg(ps, id, -1, type, -1, -1, iov, iovcnt));
763 }
764 
765 struct imsgbuf *
766 proc_ibuf(struct privsep *ps, enum privsep_procid id, int n)
767 {
768 	int	 m;
769 
770 	proc_range(ps, id, &n, &m);
771 	return (&ps->ps_ievs[id][n].ibuf);
772 }
773 
774 struct imsgev *
775 proc_iev(struct privsep *ps, enum privsep_procid id, int n)
776 {
777 	int	 m;
778 
779 	proc_range(ps, id, &n, &m);
780 	return (&ps->ps_ievs[id][n]);
781 }
782 
783 /* This function should only be called with care as it breaks async I/O */
784 int
785 proc_flush_imsg(struct privsep *ps, enum privsep_procid id, int n)
786 {
787 	struct imsgbuf	*ibuf;
788 	int		 m, ret = 0;
789 
790 	proc_range(ps, id, &n, &m);
791 	for (; n < m; n++) {
792 		if ((ibuf = proc_ibuf(ps, id, n)) == NULL)
793 			return (-1);
794 		if ((ret = imsgbuf_flush(ibuf)) == -1)
795 			break;
796 		imsg_event_add(&ps->ps_ievs[id][n]);
797 	}
798 
799 	return (ret);
800 }
801