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