xref: /openbsd/usr.sbin/httpd/proc.c (revision 04617fab)
1 /*	$OpenBSD: proc.c,v 1.33 2016/10/10 21:53:46 rzalamena 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/socket.h>
23 #include <sys/wait.h>
24 
25 #include <fcntl.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <unistd.h>
29 #include <string.h>
30 #include <errno.h>
31 #include <signal.h>
32 #include <pwd.h>
33 #include <event.h>
34 #include <imsg.h>
35 
36 #include "httpd.h"
37 
38 void	 proc_exec(struct privsep *, struct privsep_proc *, unsigned int,
39 	    int, char **);
40 void	 proc_setup(struct privsep *, struct privsep_proc *, unsigned int);
41 void	 proc_open(struct privsep *, int, int);
42 void	 proc_accept(struct privsep *, int, enum privsep_procid,
43 	    unsigned int);
44 void	 proc_close(struct privsep *);
45 int	 proc_ispeer(struct privsep_proc *, unsigned int, enum privsep_procid);
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 int
52 proc_ispeer(struct privsep_proc *procs, unsigned int nproc,
53     enum privsep_procid type)
54 {
55 	unsigned int	i;
56 
57 	for (i = 0; i < nproc; i++)
58 		if (procs[i].p_id == type)
59 			return (1);
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++] = "-P";
102 	proc_i = nargc;
103 	nargc++;
104 
105 	/* Point process instance arg to stack and copy the original args. */
106 	nargv[nargc++] = "-I";
107 	nargv[nargc++] = num;
108 	for (i = 1; i < (unsigned int) argc; i++)
109 		nargv[nargc++] = argv[i];
110 
111 	nargv[nargc] = NULL;
112 
113 	for (proc = 0; proc < nproc; proc++) {
114 		p = &procs[proc];
115 
116 		/* Update args with process title. */
117 		nargv[proc_i] = (char *)(uintptr_t)p->p_title;
118 
119 		/* Fire children processes. */
120 		for (i = 0; i < ps->ps_instances[p->p_id]; i++) {
121 			/* Update the process instance number. */
122 			snprintf(num, sizeof(num), "%u", i);
123 
124 			fd = ps->ps_pipes[p->p_id][i].pp_pipes[PROC_PARENT][0];
125 			ps->ps_pipes[p->p_id][i].pp_pipes[PROC_PARENT][0] = -1;
126 
127 			switch (fork()) {
128 			case -1:
129 				fatal("%s: fork", __func__);
130 				break;
131 			case 0:
132 				/* First create a new session */
133 				if (setsid() == -1)
134 					fatal("setsid");
135 
136 				/* Prepare parent socket. */
137 				if (fd != PROC_PARENT_SOCK_FILENO) {
138 					if (dup2(fd, PROC_PARENT_SOCK_FILENO)
139 					    == -1)
140 						fatal("dup2");
141 				} else if (fcntl(fd, F_SETFD, 0) == -1)
142 					fatal("fcntl");
143 
144 				execvp(argv[0], nargv);
145 				fatal("%s: execvp", __func__);
146 				break;
147 			default:
148 				/* Close child end. */
149 				close(fd);
150 				break;
151 			}
152 		}
153 	}
154 	free(nargv);
155 }
156 
157 void
158 proc_connect(struct privsep *ps)
159 {
160 	struct imsgev		*iev;
161 	unsigned int		 src, dst, inst;
162 
163 	/* Don't distribute any sockets if we are not really going to run. */
164 	if (ps->ps_noaction)
165 		return;
166 
167 	for (dst = 0; dst < PROC_MAX; dst++) {
168 		/* We don't communicate with ourselves. */
169 		if (dst == PROC_PARENT)
170 			continue;
171 
172 		for (inst = 0; inst < ps->ps_instances[dst]; inst++) {
173 			iev = &ps->ps_ievs[dst][inst];
174 			imsg_init(&iev->ibuf, ps->ps_pp->pp_pipes[dst][inst]);
175 			event_set(&iev->ev, iev->ibuf.fd, iev->events,
176 			    iev->handler, iev->data);
177 			event_add(&iev->ev, NULL);
178 		}
179 	}
180 
181 	/* Distribute the socketpair()s for everyone. */
182 	for (src = 0; src < PROC_MAX; src++)
183 		for (dst = src; dst < PROC_MAX; dst++) {
184 			/* Parent already distributed its fds. */
185 			if (src == PROC_PARENT || dst == PROC_PARENT)
186 				continue;
187 
188 			proc_open(ps, src, dst);
189 		}
190 }
191 
192 void
193 proc_init(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc,
194     int argc, char **argv, enum privsep_procid proc_id)
195 {
196 	struct privsep_proc	*p = NULL;
197 	struct privsep_pipes	*pa, *pb;
198 	unsigned int		 proc;
199 	unsigned int		 dst;
200 	int			 fds[2];
201 
202 	/* Don't initiate anything if we are not really going to run. */
203 	if (ps->ps_noaction)
204 		return;
205 
206 	if (proc_id == PROC_PARENT) {
207 		privsep_process = PROC_PARENT;
208 		proc_setup(ps, procs, nproc);
209 
210 		/*
211 		 * Create the children sockets so we can use them
212 		 * to distribute the rest of the socketpair()s using
213 		 * proc_connect() later.
214 		 */
215 		for (dst = 0; dst < PROC_MAX; dst++) {
216 			/* Don't create socket for ourselves. */
217 			if (dst == PROC_PARENT)
218 				continue;
219 
220 			for (proc = 0; proc < ps->ps_instances[dst]; proc++) {
221 				pa = &ps->ps_pipes[PROC_PARENT][0];
222 				pb = &ps->ps_pipes[dst][proc];
223 				if (socketpair(AF_UNIX,
224 				    SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
225 				    PF_UNSPEC, fds) == -1)
226 					fatal("%s: socketpair", __func__);
227 
228 				pa->pp_pipes[dst][proc] = fds[0];
229 				pb->pp_pipes[PROC_PARENT][0] = fds[1];
230 			}
231 		}
232 
233 		/* Engage! */
234 		proc_exec(ps, procs, nproc, argc, argv);
235 		return;
236 	}
237 
238 	/* Initialize a child */
239 	for (proc = 0; proc < nproc; proc++) {
240 		if (procs[proc].p_id != proc_id)
241 			continue;
242 		p = &procs[proc];
243 		break;
244 	}
245 	if (p == NULL || p->p_init == NULL)
246 		fatalx("%s: process %d missing process initialization",
247 		    __func__, proc_id);
248 
249 	p->p_init(ps, p);
250 
251 	fatalx("failed to initiate child process");
252 }
253 
254 void
255 proc_accept(struct privsep *ps, int fd, enum privsep_procid dst,
256     unsigned int n)
257 {
258 	struct privsep_pipes	*pp = ps->ps_pp;
259 	struct imsgev		*iev;
260 
261 	if (ps->ps_ievs[dst] == NULL) {
262 #if DEBUG > 1
263 		log_debug("%s: %s src %d %d to dst %d %d not connected",
264 		    __func__, ps->ps_title[privsep_process],
265 		    privsep_process, ps->ps_instance + 1,
266 		    dst, n + 1);
267 #endif
268 		close(fd);
269 		return;
270 	}
271 
272 	if (pp->pp_pipes[dst][n] != -1) {
273 		log_warnx("%s: duplicated descriptor", __func__);
274 		close(fd);
275 		return;
276 	} else
277 		pp->pp_pipes[dst][n] = fd;
278 
279 	iev = &ps->ps_ievs[dst][n];
280 	imsg_init(&iev->ibuf, fd);
281 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
282 	event_add(&iev->ev, NULL);
283 }
284 
285 void
286 proc_setup(struct privsep *ps, struct privsep_proc *procs, unsigned int nproc)
287 {
288 	unsigned int		 i, j, src, dst, id;
289 	struct privsep_pipes	*pp;
290 
291 	/* Initialize parent title, ps_instances and procs. */
292 	ps->ps_title[PROC_PARENT] = "parent";
293 
294 	for (src = 0; src < PROC_MAX; src++)
295 		/* Default to 1 process instance */
296 		if (ps->ps_instances[src] < 1)
297 			ps->ps_instances[src] = 1;
298 
299 	for (src = 0; src < nproc; src++) {
300 		procs[src].p_ps = ps;
301 		if (procs[src].p_cb == NULL)
302 			procs[src].p_cb = proc_dispatch_null;
303 
304 		id = procs[src].p_id;
305 		ps->ps_title[id] = procs[src].p_title;
306 		if ((ps->ps_ievs[id] = calloc(ps->ps_instances[id],
307 		    sizeof(struct imsgev))) == NULL)
308 			fatal("%s: calloc", __func__);
309 
310 		/* With this set up, we are ready to call imsg_init(). */
311 		for (i = 0; i < ps->ps_instances[id]; i++) {
312 			ps->ps_ievs[id][i].handler = proc_dispatch;
313 			ps->ps_ievs[id][i].events = EV_READ;
314 			ps->ps_ievs[id][i].proc = &procs[src];
315 			ps->ps_ievs[id][i].data = &ps->ps_ievs[id][i];
316 		}
317 	}
318 
319 	/*
320 	 * Allocate pipes for all process instances (incl. parent)
321 	 *
322 	 * - ps->ps_pipes: N:M mapping
323 	 * N source processes connected to M destination processes:
324 	 * [src][instances][dst][instances], for example
325 	 * [PROC_RELAY][3][PROC_CA][3]
326 	 *
327 	 * - ps->ps_pp: per-process 1:M part of ps->ps_pipes
328 	 * Each process instance has a destination array of socketpair fds:
329 	 * [dst][instances], for example
330 	 * [PROC_PARENT][0]
331 	 */
332 	for (src = 0; src < PROC_MAX; src++) {
333 		/* Allocate destination array for each process */
334 		if ((ps->ps_pipes[src] = calloc(ps->ps_instances[src],
335 		    sizeof(struct privsep_pipes))) == NULL)
336 			fatal("%s: calloc", __func__);
337 
338 		for (i = 0; i < ps->ps_instances[src]; i++) {
339 			pp = &ps->ps_pipes[src][i];
340 
341 			for (dst = 0; dst < PROC_MAX; dst++) {
342 				/* Allocate maximum fd integers */
343 				if ((pp->pp_pipes[dst] =
344 				    calloc(ps->ps_instances[dst],
345 				    sizeof(int))) == NULL)
346 					fatal("%s: calloc", __func__);
347 
348 				/* Mark fd as unused */
349 				for (j = 0; j < ps->ps_instances[dst]; j++)
350 					pp->pp_pipes[dst][j] = -1;
351 			}
352 		}
353 	}
354 
355 	ps->ps_pp = &ps->ps_pipes[privsep_process][ps->ps_instance];
356 }
357 
358 void
359 proc_kill(struct privsep *ps)
360 {
361 	char		*cause;
362 	pid_t		 pid;
363 	int		 len, status;
364 
365 	if (privsep_process != PROC_PARENT)
366 		return;
367 
368 	proc_close(ps);
369 
370 	do {
371 		pid = waitpid(WAIT_ANY, &status, 0);
372 		if (pid <= 0)
373 			continue;
374 
375 		if (WIFSIGNALED(status)) {
376 			len = asprintf(&cause, "terminated; signal %d",
377 			    WTERMSIG(status));
378 		} else if (WIFEXITED(status)) {
379 			if (WEXITSTATUS(status) != 0)
380 				len = asprintf(&cause, "exited abnormally");
381 			else
382 				len = 0;
383 		} else
384 			len = -1;
385 
386 		if (len == 0) {
387 			/* child exited OK, don't print a warning message */
388 		} else if (len != -1) {
389 			log_warnx("lost child: pid %u %s", pid, cause);
390 			free(cause);
391 		} else
392 			log_warnx("lost child: pid %u", pid);
393 	} while (pid != -1 || (pid == -1 && errno == EINTR));
394 }
395 
396 void
397 proc_open(struct privsep *ps, int src, int dst)
398 {
399 	struct privsep_pipes	*pa, *pb;
400 	struct privsep_fd	 pf;
401 	int			 fds[2];
402 	unsigned int		 i, j;
403 
404 	/* Exchange pipes between process. */
405 	for (i = 0; i < ps->ps_instances[src]; i++) {
406 		for (j = 0; j < ps->ps_instances[dst]; j++) {
407 			/* Don't create sockets for ourself. */
408 			if (src == dst && i == j)
409 				continue;
410 
411 			pa = &ps->ps_pipes[src][i];
412 			pb = &ps->ps_pipes[dst][j];
413 			if (socketpair(AF_UNIX,
414 			    SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC,
415 			    PF_UNSPEC, fds) == -1)
416 				fatal("%s: socketpair", __func__);
417 
418 			pa->pp_pipes[dst][j] = fds[0];
419 			pb->pp_pipes[src][i] = fds[1];
420 
421 			pf.pf_procid = src;
422 			pf.pf_instance = i;
423 			if (proc_compose_imsg(ps, dst, j, IMSG_CTL_PROCFD,
424 			    -1, pb->pp_pipes[src][i], &pf, sizeof(pf)) == -1)
425 				fatal("%s: proc_compose_imsg", __func__);
426 
427 			pf.pf_procid = dst;
428 			pf.pf_instance = j;
429 			if (proc_compose_imsg(ps, src, i, IMSG_CTL_PROCFD,
430 			    -1, pa->pp_pipes[dst][j], &pf, sizeof(pf)) == -1)
431 				fatal("%s: proc_compose_imsg", __func__);
432 
433 			/*
434 			 * We have to flush to send the descriptors and close
435 			 * them to avoid the fd ramp on startup.
436 			 */
437 			if (imsg_flush(&ps->ps_ievs[src][i].ibuf) == -1 ||
438 			    imsg_flush(&ps->ps_ievs[dst][j].ibuf) == -1)
439 				fatal("%s: imsg_flush", __func__);
440 
441 			imsg_event_add(&ps->ps_ievs[src][i]);
442 			imsg_event_add(&ps->ps_ievs[dst][j]);
443 		}
444 	}
445 }
446 
447 void
448 proc_close(struct privsep *ps)
449 {
450 	unsigned int		 dst, n;
451 	struct privsep_pipes	*pp;
452 
453 	if (ps == NULL)
454 		return;
455 
456 	pp = ps->ps_pp;
457 
458 	for (dst = 0; dst < PROC_MAX; dst++) {
459 		if (ps->ps_ievs[dst] == NULL)
460 			continue;
461 
462 		for (n = 0; n < ps->ps_instances[dst]; n++) {
463 			if (pp->pp_pipes[dst][n] == -1)
464 				continue;
465 
466 			/* Cancel the fd, close and invalidate the fd */
467 			event_del(&(ps->ps_ievs[dst][n].ev));
468 			imsg_clear(&(ps->ps_ievs[dst][n].ibuf));
469 			close(pp->pp_pipes[dst][n]);
470 			pp->pp_pipes[dst][n] = -1;
471 		}
472 		free(ps->ps_ievs[dst]);
473 	}
474 }
475 
476 void
477 proc_shutdown(struct privsep_proc *p)
478 {
479 	struct privsep	*ps = p->p_ps;
480 
481 	if (p->p_id == PROC_CONTROL && ps)
482 		control_cleanup(&ps->ps_csock);
483 
484 	if (p->p_shutdown != NULL)
485 		(*p->p_shutdown)();
486 
487 	proc_close(ps);
488 
489 	log_info("%s exiting, pid %d", p->p_title, getpid());
490 
491 	exit(0);
492 }
493 
494 void
495 proc_sig_handler(int sig, short event, void *arg)
496 {
497 	struct privsep_proc	*p = arg;
498 
499 	switch (sig) {
500 	case SIGINT:
501 	case SIGTERM:
502 		proc_shutdown(p);
503 		break;
504 	case SIGCHLD:
505 	case SIGHUP:
506 	case SIGPIPE:
507 	case SIGUSR1:
508 		/* ignore */
509 		break;
510 	default:
511 		fatalx("proc_sig_handler: unexpected signal");
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 	struct control_sock	*rcs;
524 
525 	log_procinit(p->p_title);
526 
527 	/* Set the process group of the current process */
528 	setpgid(0, 0);
529 
530 	if (p->p_id == PROC_CONTROL && ps->ps_instance == 0) {
531 		if (control_init(ps, &ps->ps_csock) == -1)
532 			fatalx("%s: control_init", __func__);
533 		TAILQ_FOREACH(rcs, &ps->ps_rcsocks, cs_entry)
534 			if (control_init(ps, rcs) == -1)
535 				fatalx("%s: control_init", __func__);
536 	}
537 
538 	/* Use non-standard user */
539 	if (p->p_pw != NULL)
540 		pw = p->p_pw;
541 	else
542 		pw = ps->ps_pw;
543 
544 	/* Change root directory */
545 	if (p->p_chroot != NULL)
546 		root = p->p_chroot;
547 	else
548 		root = pw->pw_dir;
549 
550 	if (chroot(root) == -1)
551 		fatal("proc_run: chroot");
552 	if (chdir("/") == -1)
553 		fatal("proc_run: chdir(\"/\")");
554 
555 	privsep_process = p->p_id;
556 
557 	setproctitle("%s", p->p_title);
558 
559 	if (setgroups(1, &pw->pw_gid) ||
560 	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
561 	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
562 		fatal("proc_run: cannot drop privileges");
563 
564 	event_init();
565 
566 	signal_set(&ps->ps_evsigint, SIGINT, proc_sig_handler, p);
567 	signal_set(&ps->ps_evsigterm, SIGTERM, proc_sig_handler, p);
568 	signal_set(&ps->ps_evsigchld, SIGCHLD, proc_sig_handler, p);
569 	signal_set(&ps->ps_evsighup, SIGHUP, proc_sig_handler, p);
570 	signal_set(&ps->ps_evsigpipe, SIGPIPE, proc_sig_handler, p);
571 	signal_set(&ps->ps_evsigusr1, SIGUSR1, proc_sig_handler, p);
572 
573 	signal_add(&ps->ps_evsigint, NULL);
574 	signal_add(&ps->ps_evsigterm, NULL);
575 	signal_add(&ps->ps_evsigchld, NULL);
576 	signal_add(&ps->ps_evsighup, NULL);
577 	signal_add(&ps->ps_evsigpipe, NULL);
578 	signal_add(&ps->ps_evsigusr1, NULL);
579 
580 	proc_setup(ps, procs, nproc);
581 	proc_accept(ps, PROC_PARENT_SOCK_FILENO, PROC_PARENT, 0);
582 	if (p->p_id == PROC_CONTROL && ps->ps_instance == 0) {
583 		TAILQ_INIT(&ctl_conns);
584 		if (control_listen(&ps->ps_csock) == -1)
585 			fatalx("%s: control_listen", __func__);
586 		TAILQ_FOREACH(rcs, &ps->ps_rcsocks, cs_entry)
587 			if (control_listen(rcs) == -1)
588 				fatalx("%s: control_listen", __func__);
589 	}
590 
591 	DPRINTF("%s: %s %d/%d, pid %d", __func__, p->p_title,
592 	    ps->ps_instance + 1, ps->ps_instances[p->p_id], getpid());
593 
594 	if (run != NULL)
595 		run(ps, p, arg);
596 
597 	event_dispatch();
598 
599 	proc_shutdown(p);
600 }
601 
602 void
603 proc_dispatch(int fd, short event, void *arg)
604 {
605 	struct imsgev		*iev = arg;
606 	struct privsep_proc	*p = iev->proc;
607 	struct privsep		*ps = p->p_ps;
608 	struct imsgbuf		*ibuf;
609 	struct imsg		 imsg;
610 	ssize_t			 n;
611 	int			 verbose;
612 	const char		*title;
613 	struct privsep_fd	 pf;
614 
615 	title = ps->ps_title[privsep_process];
616 	ibuf = &iev->ibuf;
617 
618 	if (event & EV_READ) {
619 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
620 			fatal("%s: imsg_read", __func__);
621 		if (n == 0) {
622 			/* this pipe is dead, so remove the event handler */
623 			event_del(&iev->ev);
624 			event_loopexit(NULL);
625 			return;
626 		}
627 	}
628 
629 	if (event & EV_WRITE) {
630 		if ((n = msgbuf_write(&ibuf->w)) == -1 && errno != EAGAIN)
631 			fatal("%s: msgbuf_write", __func__);
632 		if (n == 0) {
633 			/* this pipe is dead, so remove the event handler */
634 			event_del(&iev->ev);
635 			event_loopexit(NULL);
636 			return;
637 		}
638 	}
639 
640 	for (;;) {
641 		if ((n = imsg_get(ibuf, &imsg)) == -1)
642 			fatal("%s: imsg_get", __func__);
643 		if (n == 0)
644 			break;
645 
646 #if DEBUG > 1
647 		log_debug("%s: %s %d got imsg %d peerid %d from %s %d",
648 		    __func__, title, ps->ps_instance + 1,
649 		    imsg.hdr.type, imsg.hdr.peerid, p->p_title, imsg.hdr.pid);
650 #endif
651 
652 		/*
653 		 * Check the message with the program callback
654 		 */
655 		if ((p->p_cb)(fd, p, &imsg) == 0) {
656 			/* Message was handled by the callback, continue */
657 			imsg_free(&imsg);
658 			continue;
659 		}
660 
661 		/*
662 		 * Generic message handling
663 		 */
664 		switch (imsg.hdr.type) {
665 		case IMSG_CTL_VERBOSE:
666 			IMSG_SIZE_CHECK(&imsg, &verbose);
667 			memcpy(&verbose, imsg.data, sizeof(verbose));
668 			log_verbose(verbose);
669 			break;
670 		case IMSG_CTL_PROCFD:
671 			IMSG_SIZE_CHECK(&imsg, &pf);
672 			memcpy(&pf, imsg.data, sizeof(pf));
673 			proc_accept(ps, imsg.fd, pf.pf_procid,
674 			    pf.pf_instance);
675 			break;
676 		default:
677 			fatalx("%s: %s %d got invalid imsg %d peerid %d "
678 			    "from %s %d",
679 			    __func__, title, ps->ps_instance + 1,
680 			    imsg.hdr.type, imsg.hdr.peerid,
681 			    p->p_title, imsg.hdr.pid);
682 		}
683 		imsg_free(&imsg);
684 	}
685 	imsg_event_add(iev);
686 }
687 
688 int
689 proc_dispatch_null(int fd, struct privsep_proc *p, struct imsg *imsg)
690 {
691 	return (-1);
692 }
693 
694 /*
695  * imsg helper functions
696  */
697 
698 void
699 imsg_event_add(struct imsgev *iev)
700 {
701 	if (iev->handler == NULL) {
702 		imsg_flush(&iev->ibuf);
703 		return;
704 	}
705 
706 	iev->events = EV_READ;
707 	if (iev->ibuf.w.queued)
708 		iev->events |= EV_WRITE;
709 
710 	event_del(&iev->ev);
711 	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
712 	event_add(&iev->ev, NULL);
713 }
714 
715 int
716 imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
717     pid_t pid, int fd, void *data, uint16_t datalen)
718 {
719 	int	ret;
720 
721 	if ((ret = imsg_compose(&iev->ibuf, type, peerid,
722 	    pid, fd, data, datalen)) == -1)
723 		return (ret);
724 	imsg_event_add(iev);
725 	return (ret);
726 }
727 
728 int
729 imsg_composev_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
730     pid_t pid, int fd, const struct iovec *iov, int iovcnt)
731 {
732 	int	ret;
733 
734 	if ((ret = imsg_composev(&iev->ibuf, type, peerid,
735 	    pid, fd, iov, iovcnt)) == -1)
736 		return (ret);
737 	imsg_event_add(iev);
738 	return (ret);
739 }
740 
741 void
742 proc_range(struct privsep *ps, enum privsep_procid id, int *n, int *m)
743 {
744 	if (*n == -1) {
745 		/* Use a range of all target instances */
746 		*n = 0;
747 		*m = ps->ps_instances[id];
748 	} else {
749 		/* Use only a single slot of the specified peer process */
750 		*m = *n + 1;
751 	}
752 }
753 
754 int
755 proc_compose_imsg(struct privsep *ps, enum privsep_procid id, int n,
756     uint16_t type, uint32_t peerid, int fd, void *data, uint16_t datalen)
757 {
758 	int	 m;
759 
760 	proc_range(ps, id, &n, &m);
761 	for (; n < m; n++) {
762 		if (imsg_compose_event(&ps->ps_ievs[id][n],
763 		    type, peerid, ps->ps_instance + 1, fd, data, datalen) == -1)
764 			return (-1);
765 	}
766 
767 	return (0);
768 }
769 
770 int
771 proc_compose(struct privsep *ps, enum privsep_procid id,
772     uint16_t type, void *data, uint16_t datalen)
773 {
774 	return (proc_compose_imsg(ps, id, -1, type, -1, -1, data, datalen));
775 }
776 
777 int
778 proc_composev_imsg(struct privsep *ps, enum privsep_procid id, int n,
779     uint16_t type, uint32_t peerid, int fd, const struct iovec *iov, int iovcnt)
780 {
781 	int	 m;
782 
783 	proc_range(ps, id, &n, &m);
784 	for (; n < m; n++)
785 		if (imsg_composev_event(&ps->ps_ievs[id][n],
786 		    type, peerid, ps->ps_instance + 1, fd, iov, iovcnt) == -1)
787 			return (-1);
788 
789 	return (0);
790 }
791 
792 int
793 proc_composev(struct privsep *ps, enum privsep_procid id,
794     uint16_t type, const struct iovec *iov, int iovcnt)
795 {
796 	return (proc_composev_imsg(ps, id, -1, type, -1, -1, iov, iovcnt));
797 }
798 
799 int
800 proc_forward_imsg(struct privsep *ps, struct imsg *imsg,
801     enum privsep_procid id, int n)
802 {
803 	return (proc_compose_imsg(ps, id, n, imsg->hdr.type,
804 	    imsg->hdr.peerid, imsg->fd, imsg->data, IMSG_DATA_SIZE(imsg)));
805 }
806 
807 struct imsgbuf *
808 proc_ibuf(struct privsep *ps, enum privsep_procid id, int n)
809 {
810 	int	 m;
811 
812 	proc_range(ps, id, &n, &m);
813 	return (&ps->ps_ievs[id][n].ibuf);
814 }
815 
816 struct imsgev *
817 proc_iev(struct privsep *ps, enum privsep_procid id, int n)
818 {
819 	int	 m;
820 
821 	proc_range(ps, id, &n, &m);
822 	return (&ps->ps_ievs[id][n]);
823 }
824