xref: /freebsd/sys/kern/kern_procctl.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * Copyright (c) 2014 John Baldwin
3  * Copyright (c) 2014, 2016 The FreeBSD Foundation
4  *
5  * Portions of this software were developed by Konstantin Belousov
6  * under sponsorship from the FreeBSD Foundation.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/param.h>
31 #include <sys/_unrhdr.h>
32 #include <sys/systm.h>
33 #include <sys/capsicum.h>
34 #include <sys/lock.h>
35 #include <sys/mman.h>
36 #include <sys/mutex.h>
37 #include <sys/priv.h>
38 #include <sys/proc.h>
39 #include <sys/procctl.h>
40 #include <sys/sx.h>
41 #include <sys/syscallsubr.h>
42 #include <sys/sysproto.h>
43 #include <sys/taskqueue.h>
44 #include <sys/wait.h>
45 
46 #include <vm/vm.h>
47 #include <vm/pmap.h>
48 #include <vm/vm_map.h>
49 #include <vm/vm_extern.h>
50 
51 static int
52 protect_setchild(struct thread *td, struct proc *p, int flags)
53 {
54 
55 	PROC_LOCK_ASSERT(p, MA_OWNED);
56 	if (p->p_flag & P_SYSTEM || p_cansched(td, p) != 0)
57 		return (0);
58 	if (flags & PPROT_SET) {
59 		p->p_flag |= P_PROTECTED;
60 		if (flags & PPROT_INHERIT)
61 			p->p_flag2 |= P2_INHERIT_PROTECTED;
62 	} else {
63 		p->p_flag &= ~P_PROTECTED;
64 		p->p_flag2 &= ~P2_INHERIT_PROTECTED;
65 	}
66 	return (1);
67 }
68 
69 static int
70 protect_setchildren(struct thread *td, struct proc *top, int flags)
71 {
72 	struct proc *p;
73 	int ret;
74 
75 	p = top;
76 	ret = 0;
77 	sx_assert(&proctree_lock, SX_LOCKED);
78 	for (;;) {
79 		ret |= protect_setchild(td, p, flags);
80 		PROC_UNLOCK(p);
81 		/*
82 		 * If this process has children, descend to them next,
83 		 * otherwise do any siblings, and if done with this level,
84 		 * follow back up the tree (but not past top).
85 		 */
86 		if (!LIST_EMPTY(&p->p_children))
87 			p = LIST_FIRST(&p->p_children);
88 		else for (;;) {
89 			if (p == top) {
90 				PROC_LOCK(p);
91 				return (ret);
92 			}
93 			if (LIST_NEXT(p, p_sibling)) {
94 				p = LIST_NEXT(p, p_sibling);
95 				break;
96 			}
97 			p = p->p_pptr;
98 		}
99 		PROC_LOCK(p);
100 	}
101 }
102 
103 static int
104 protect_set(struct thread *td, struct proc *p, void *data)
105 {
106 	int error, flags, ret;
107 
108 	flags = *(int *)data;
109 	switch (PPROT_OP(flags)) {
110 	case PPROT_SET:
111 	case PPROT_CLEAR:
112 		break;
113 	default:
114 		return (EINVAL);
115 	}
116 
117 	if ((PPROT_FLAGS(flags) & ~(PPROT_DESCEND | PPROT_INHERIT)) != 0)
118 		return (EINVAL);
119 
120 	error = priv_check(td, PRIV_VM_MADV_PROTECT);
121 	if (error)
122 		return (error);
123 
124 	if (flags & PPROT_DESCEND)
125 		ret = protect_setchildren(td, p, flags);
126 	else
127 		ret = protect_setchild(td, p, flags);
128 	if (ret == 0)
129 		return (EPERM);
130 	return (0);
131 }
132 
133 static int
134 reap_acquire(struct thread *td, struct proc *p, void *data __unused)
135 {
136 
137 	sx_assert(&proctree_lock, SX_XLOCKED);
138 	if (p != td->td_proc)
139 		return (EPERM);
140 	if ((p->p_treeflag & P_TREE_REAPER) != 0)
141 		return (EBUSY);
142 	p->p_treeflag |= P_TREE_REAPER;
143 	/*
144 	 * We do not reattach existing children and the whole tree
145 	 * under them to us, since p->p_reaper already seen them.
146 	 */
147 	return (0);
148 }
149 
150 static int
151 reap_release(struct thread *td, struct proc *p, void *data __unused)
152 {
153 
154 	sx_assert(&proctree_lock, SX_XLOCKED);
155 	if (p != td->td_proc)
156 		return (EPERM);
157 	if (p == initproc)
158 		return (EINVAL);
159 	if ((p->p_treeflag & P_TREE_REAPER) == 0)
160 		return (EINVAL);
161 	reaper_abandon_children(p, false);
162 	return (0);
163 }
164 
165 static int
166 reap_status(struct thread *td, struct proc *p, void *data)
167 {
168 	struct proc *reap, *p2, *first_p;
169 	struct procctl_reaper_status *rs;
170 
171 	rs = data;
172 	sx_assert(&proctree_lock, SX_LOCKED);
173 	if ((p->p_treeflag & P_TREE_REAPER) == 0) {
174 		reap = p->p_reaper;
175 	} else {
176 		reap = p;
177 		rs->rs_flags |= REAPER_STATUS_OWNED;
178 	}
179 	if (reap == initproc)
180 		rs->rs_flags |= REAPER_STATUS_REALINIT;
181 	rs->rs_reaper = reap->p_pid;
182 	rs->rs_descendants = 0;
183 	rs->rs_children = 0;
184 	if (!LIST_EMPTY(&reap->p_reaplist)) {
185 		first_p = LIST_FIRST(&reap->p_children);
186 		if (first_p == NULL)
187 			first_p = LIST_FIRST(&reap->p_reaplist);
188 		rs->rs_pid = first_p->p_pid;
189 		LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
190 			if (proc_realparent(p2) == reap)
191 				rs->rs_children++;
192 			rs->rs_descendants++;
193 		}
194 	} else {
195 		rs->rs_pid = -1;
196 	}
197 	return (0);
198 }
199 
200 static int
201 reap_getpids(struct thread *td, struct proc *p, void *data)
202 {
203 	struct proc *reap, *p2;
204 	struct procctl_reaper_pidinfo *pi, *pip;
205 	struct procctl_reaper_pids *rp;
206 	u_int i, n;
207 	int error;
208 
209 	rp = data;
210 	sx_assert(&proctree_lock, SX_LOCKED);
211 	PROC_UNLOCK(p);
212 	reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
213 	n = i = 0;
214 	error = 0;
215 	LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling)
216 		n++;
217 	sx_unlock(&proctree_lock);
218 	if (rp->rp_count < n)
219 		n = rp->rp_count;
220 	pi = malloc(n * sizeof(*pi), M_TEMP, M_WAITOK);
221 	sx_slock(&proctree_lock);
222 	LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
223 		if (i == n)
224 			break;
225 		pip = &pi[i];
226 		bzero(pip, sizeof(*pip));
227 		pip->pi_pid = p2->p_pid;
228 		pip->pi_subtree = p2->p_reapsubtree;
229 		pip->pi_flags = REAPER_PIDINFO_VALID;
230 		if (proc_realparent(p2) == reap)
231 			pip->pi_flags |= REAPER_PIDINFO_CHILD;
232 		if ((p2->p_treeflag & P_TREE_REAPER) != 0)
233 			pip->pi_flags |= REAPER_PIDINFO_REAPER;
234 		if ((p2->p_flag & P_STOPPED) != 0)
235 			pip->pi_flags |= REAPER_PIDINFO_STOPPED;
236 		if (p2->p_state == PRS_ZOMBIE)
237 			pip->pi_flags |= REAPER_PIDINFO_ZOMBIE;
238 		else if ((p2->p_flag & P_WEXIT) != 0)
239 			pip->pi_flags |= REAPER_PIDINFO_EXITING;
240 		i++;
241 	}
242 	sx_sunlock(&proctree_lock);
243 	error = copyout(pi, rp->rp_pids, i * sizeof(*pi));
244 	free(pi, M_TEMP);
245 	sx_slock(&proctree_lock);
246 	PROC_LOCK(p);
247 	return (error);
248 }
249 
250 struct reap_kill_proc_work {
251 	struct ucred *cr;
252 	struct proc *target;
253 	ksiginfo_t *ksi;
254 	struct procctl_reaper_kill *rk;
255 	int *error;
256 	struct task t;
257 };
258 
259 static void
260 reap_kill_proc_locked(struct reap_kill_proc_work *w)
261 {
262 	int error1;
263 	bool need_stop;
264 
265 	PROC_LOCK_ASSERT(w->target, MA_OWNED);
266 	PROC_ASSERT_HELD(w->target);
267 
268 	error1 = cr_cansignal(w->cr, w->target, w->rk->rk_sig);
269 	if (error1 != 0) {
270 		if (*w->error == ESRCH) {
271 			w->rk->rk_fpid = w->target->p_pid;
272 			*w->error = error1;
273 		}
274 		return;
275 	}
276 
277 	/*
278 	 * The need_stop indicates if the target process needs to be
279 	 * suspended before being signalled.  This is needed when we
280 	 * guarantee that all processes in subtree are signalled,
281 	 * avoiding the race with some process not yet fully linked
282 	 * into all structures during fork, ignored by iterator, and
283 	 * then escaping signalling.
284 	 *
285 	 * The thread cannot usefully stop itself anyway, and if other
286 	 * thread of the current process forks while the current
287 	 * thread signals the whole subtree, it is an application
288 	 * race.
289 	 */
290 	if ((w->target->p_flag & (P_KPROC | P_SYSTEM | P_STOPPED)) == 0)
291 		need_stop = thread_single(w->target, SINGLE_ALLPROC) == 0;
292 	else
293 		need_stop = false;
294 
295 	(void)pksignal(w->target, w->rk->rk_sig, w->ksi);
296 	w->rk->rk_killed++;
297 	*w->error = error1;
298 
299 	if (need_stop)
300 		thread_single_end(w->target, SINGLE_ALLPROC);
301 }
302 
303 static void
304 reap_kill_proc_work(void *arg, int pending __unused)
305 {
306 	struct reap_kill_proc_work *w;
307 
308 	w = arg;
309 	PROC_LOCK(w->target);
310 	if ((w->target->p_flag2 & P2_WEXIT) == 0)
311 		reap_kill_proc_locked(w);
312 	PROC_UNLOCK(w->target);
313 
314 	sx_xlock(&proctree_lock);
315 	w->target = NULL;
316 	wakeup(&w->target);
317 	sx_xunlock(&proctree_lock);
318 }
319 
320 struct reap_kill_tracker {
321 	struct proc *parent;
322 	TAILQ_ENTRY(reap_kill_tracker) link;
323 };
324 
325 TAILQ_HEAD(reap_kill_tracker_head, reap_kill_tracker);
326 
327 static void
328 reap_kill_sched(struct reap_kill_tracker_head *tracker, struct proc *p2)
329 {
330 	struct reap_kill_tracker *t;
331 
332 	PROC_LOCK(p2);
333 	if ((p2->p_flag2 & P2_WEXIT) != 0) {
334 		PROC_UNLOCK(p2);
335 		return;
336 	}
337 	_PHOLD_LITE(p2);
338 	PROC_UNLOCK(p2);
339 	t = malloc(sizeof(struct reap_kill_tracker), M_TEMP, M_WAITOK);
340 	t->parent = p2;
341 	TAILQ_INSERT_TAIL(tracker, t, link);
342 }
343 
344 static void
345 reap_kill_sched_free(struct reap_kill_tracker *t)
346 {
347 	PRELE(t->parent);
348 	free(t, M_TEMP);
349 }
350 
351 static void
352 reap_kill_children(struct thread *td, struct proc *reaper,
353     struct procctl_reaper_kill *rk, ksiginfo_t *ksi, int *error)
354 {
355 	struct proc *p2;
356 	int error1;
357 
358 	LIST_FOREACH(p2, &reaper->p_children, p_sibling) {
359 		PROC_LOCK(p2);
360 		if ((p2->p_flag2 & P2_WEXIT) == 0) {
361 			error1 = p_cansignal(td, p2, rk->rk_sig);
362 			if (error1 != 0) {
363 				if (*error == ESRCH) {
364 					rk->rk_fpid = p2->p_pid;
365 					*error = error1;
366 				}
367 
368 				/*
369 				 * Do not end the loop on error,
370 				 * signal everything we can.
371 				 */
372 			} else {
373 				(void)pksignal(p2, rk->rk_sig, ksi);
374 				rk->rk_killed++;
375 			}
376 		}
377 		PROC_UNLOCK(p2);
378 	}
379 }
380 
381 static bool
382 reap_kill_subtree_once(struct thread *td, struct proc *p, struct proc *reaper,
383     struct unrhdr *pids, struct reap_kill_proc_work *w)
384 {
385 	struct reap_kill_tracker_head tracker;
386 	struct reap_kill_tracker *t;
387 	struct proc *p2;
388 	int r, xlocked;
389 	bool res, st;
390 
391 	res = false;
392 	TAILQ_INIT(&tracker);
393 	reap_kill_sched(&tracker, reaper);
394 	while ((t = TAILQ_FIRST(&tracker)) != NULL) {
395 		TAILQ_REMOVE(&tracker, t, link);
396 
397 		/*
398 		 * Since reap_kill_proc() drops proctree_lock sx, it
399 		 * is possible that the tracked reaper is no longer.
400 		 * In this case the subtree is reparented to the new
401 		 * reaper, which should handle it.
402 		 */
403 		if ((t->parent->p_treeflag & P_TREE_REAPER) == 0) {
404 			reap_kill_sched_free(t);
405 			res = true;
406 			continue;
407 		}
408 
409 		LIST_FOREACH(p2, &t->parent->p_reaplist, p_reapsibling) {
410 			if (t->parent == reaper &&
411 			    (w->rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
412 			    p2->p_reapsubtree != w->rk->rk_subtree)
413 				continue;
414 			if ((p2->p_treeflag & P_TREE_REAPER) != 0)
415 				reap_kill_sched(&tracker, p2);
416 
417 			/*
418 			 * Handle possible pid reuse.  If we recorded
419 			 * p2 as killed but its p_flag2 does not
420 			 * confirm it, that means that the process
421 			 * terminated and its id was reused by other
422 			 * process in the reaper subtree.
423 			 *
424 			 * Unlocked read of p2->p_flag2 is fine, it is
425 			 * our thread that set the tested flag.
426 			 */
427 			if (alloc_unr_specific(pids, p2->p_pid) != p2->p_pid &&
428 			    (atomic_load_int(&p2->p_flag2) &
429 			    (P2_REAPKILLED | P2_WEXIT)) != 0)
430 				continue;
431 
432 			if (p2 == td->td_proc) {
433 				if ((p2->p_flag & P_HADTHREADS) != 0 &&
434 				    (p2->p_flag2 & P2_WEXIT) == 0) {
435 					xlocked = sx_xlocked(&proctree_lock);
436 					sx_unlock(&proctree_lock);
437 					st = true;
438 				} else {
439 					st = false;
440 				}
441 				PROC_LOCK(p2);
442 				/*
443 				 * sapblk ensures that only one thread
444 				 * in the system sets this flag.
445 				 */
446 				p2->p_flag2 |= P2_REAPKILLED;
447 				if (st)
448 					r = thread_single(p2, SINGLE_NO_EXIT);
449 				(void)pksignal(p2, w->rk->rk_sig, w->ksi);
450 				w->rk->rk_killed++;
451 				if (st && r == 0)
452 					thread_single_end(p2, SINGLE_NO_EXIT);
453 				PROC_UNLOCK(p2);
454 				if (st) {
455 					if (xlocked)
456 						sx_xlock(&proctree_lock);
457 					else
458 						sx_slock(&proctree_lock);
459 				}
460 			} else {
461 				PROC_LOCK(p2);
462 				if ((p2->p_flag2 & P2_WEXIT) == 0) {
463 					_PHOLD_LITE(p2);
464 					p2->p_flag2 |= P2_REAPKILLED;
465 					PROC_UNLOCK(p2);
466 					w->target = p2;
467 					taskqueue_enqueue(taskqueue_thread,
468 					    &w->t);
469 					while (w->target != NULL) {
470 						sx_sleep(&w->target,
471 						    &proctree_lock, PWAIT,
472 						    "reapst", 0);
473 					}
474 					PROC_LOCK(p2);
475 					_PRELE(p2);
476 				}
477 				PROC_UNLOCK(p2);
478 			}
479 			res = true;
480 		}
481 		reap_kill_sched_free(t);
482 	}
483 	return (res);
484 }
485 
486 static void
487 reap_kill_subtree(struct thread *td, struct proc *p, struct proc *reaper,
488     struct reap_kill_proc_work *w)
489 {
490 	struct unrhdr pids;
491 	void *ihandle;
492 	struct proc *p2;
493 	int pid;
494 
495 	/*
496 	 * pids records processes which were already signalled, to
497 	 * avoid doubling signals to them if iteration needs to be
498 	 * repeated.
499 	 */
500 	init_unrhdr(&pids, 1, PID_MAX, UNR_NO_MTX);
501 	PROC_LOCK(td->td_proc);
502 	if ((td->td_proc->p_flag2 & P2_WEXIT) != 0) {
503 		PROC_UNLOCK(td->td_proc);
504 		goto out;
505 	}
506 	PROC_UNLOCK(td->td_proc);
507 	while (reap_kill_subtree_once(td, p, reaper, &pids, w))
508 	       ;
509 
510 	ihandle = create_iter_unr(&pids);
511 	while ((pid = next_iter_unr(ihandle)) != -1) {
512 		p2 = pfind(pid);
513 		if (p2 != NULL) {
514 			p2->p_flag2 &= ~P2_REAPKILLED;
515 			PROC_UNLOCK(p2);
516 		}
517 	}
518 	free_iter_unr(ihandle);
519 
520 out:
521 	clean_unrhdr(&pids);
522 	clear_unrhdr(&pids);
523 }
524 
525 static bool
526 reap_kill_sapblk(struct thread *td __unused, void *data)
527 {
528 	struct procctl_reaper_kill *rk;
529 
530 	rk = data;
531 	return ((rk->rk_flags & REAPER_KILL_CHILDREN) == 0);
532 }
533 
534 static int
535 reap_kill(struct thread *td, struct proc *p, void *data)
536 {
537 	struct reap_kill_proc_work w;
538 	struct proc *reaper;
539 	ksiginfo_t ksi;
540 	struct procctl_reaper_kill *rk;
541 	int error;
542 
543 	rk = data;
544 	sx_assert(&proctree_lock, SX_LOCKED);
545 	if (IN_CAPABILITY_MODE(td))
546 		return (ECAPMODE);
547 	if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG ||
548 	    (rk->rk_flags & ~(REAPER_KILL_CHILDREN |
549 	    REAPER_KILL_SUBTREE)) != 0 || (rk->rk_flags &
550 	    (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE)) ==
551 	    (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE))
552 		return (EINVAL);
553 	PROC_UNLOCK(p);
554 	reaper = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
555 	ksiginfo_init(&ksi);
556 	ksi.ksi_signo = rk->rk_sig;
557 	ksi.ksi_code = SI_USER;
558 	ksi.ksi_pid = td->td_proc->p_pid;
559 	ksi.ksi_uid = td->td_ucred->cr_ruid;
560 	error = ESRCH;
561 	rk->rk_killed = 0;
562 	rk->rk_fpid = -1;
563 	if ((rk->rk_flags & REAPER_KILL_CHILDREN) != 0) {
564 		reap_kill_children(td, reaper, rk, &ksi, &error);
565 	} else {
566 		w.cr = crhold(td->td_ucred);
567 		w.ksi = &ksi;
568 		w.rk = rk;
569 		w.error = &error;
570 		TASK_INIT(&w.t, 0, reap_kill_proc_work, &w);
571 
572 		/*
573 		 * Prevent swapout, since w, ksi, and possibly rk, are
574 		 * allocated on the stack.  We sleep in
575 		 * reap_kill_subtree_once() waiting for task to
576 		 * complete single-threading.
577 		 */
578 		PHOLD(td->td_proc);
579 
580 		reap_kill_subtree(td, p, reaper, &w);
581 		PRELE(td->td_proc);
582 		crfree(w.cr);
583 	}
584 	PROC_LOCK(p);
585 	return (error);
586 }
587 
588 static int
589 trace_ctl(struct thread *td, struct proc *p, void *data)
590 {
591 	int state;
592 
593 	PROC_LOCK_ASSERT(p, MA_OWNED);
594 	state = *(int *)data;
595 
596 	/*
597 	 * Ktrace changes p_traceflag from or to zero under the
598 	 * process lock, so the test does not need to acquire ktrace
599 	 * mutex.
600 	 */
601 	if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0)
602 		return (EBUSY);
603 
604 	switch (state) {
605 	case PROC_TRACE_CTL_ENABLE:
606 		if (td->td_proc != p)
607 			return (EPERM);
608 		p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC);
609 		break;
610 	case PROC_TRACE_CTL_DISABLE_EXEC:
611 		p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE;
612 		break;
613 	case PROC_TRACE_CTL_DISABLE:
614 		if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) {
615 			KASSERT((p->p_flag2 & P2_NOTRACE) != 0,
616 			    ("dandling P2_NOTRACE_EXEC"));
617 			if (td->td_proc != p)
618 				return (EPERM);
619 			p->p_flag2 &= ~P2_NOTRACE_EXEC;
620 		} else {
621 			p->p_flag2 |= P2_NOTRACE;
622 		}
623 		break;
624 	default:
625 		return (EINVAL);
626 	}
627 	return (0);
628 }
629 
630 static int
631 trace_status(struct thread *td, struct proc *p, void *data)
632 {
633 	int *status;
634 
635 	status = data;
636 	if ((p->p_flag2 & P2_NOTRACE) != 0) {
637 		KASSERT((p->p_flag & P_TRACED) == 0,
638 		    ("%d traced but tracing disabled", p->p_pid));
639 		*status = -1;
640 	} else if ((p->p_flag & P_TRACED) != 0) {
641 		*status = p->p_pptr->p_pid;
642 	} else {
643 		*status = 0;
644 	}
645 	return (0);
646 }
647 
648 static int
649 trapcap_ctl(struct thread *td, struct proc *p, void *data)
650 {
651 	int state;
652 
653 	PROC_LOCK_ASSERT(p, MA_OWNED);
654 	state = *(int *)data;
655 
656 	switch (state) {
657 	case PROC_TRAPCAP_CTL_ENABLE:
658 		p->p_flag2 |= P2_TRAPCAP;
659 		break;
660 	case PROC_TRAPCAP_CTL_DISABLE:
661 		p->p_flag2 &= ~P2_TRAPCAP;
662 		break;
663 	default:
664 		return (EINVAL);
665 	}
666 	return (0);
667 }
668 
669 static int
670 trapcap_status(struct thread *td, struct proc *p, void *data)
671 {
672 	int *status;
673 
674 	status = data;
675 	*status = (p->p_flag2 & P2_TRAPCAP) != 0 ? PROC_TRAPCAP_CTL_ENABLE :
676 	    PROC_TRAPCAP_CTL_DISABLE;
677 	return (0);
678 }
679 
680 static int
681 no_new_privs_ctl(struct thread *td, struct proc *p, void *data)
682 {
683 	int state;
684 
685 	PROC_LOCK_ASSERT(p, MA_OWNED);
686 	state = *(int *)data;
687 
688 	if (state != PROC_NO_NEW_PRIVS_ENABLE)
689 		return (EINVAL);
690 	p->p_flag2 |= P2_NO_NEW_PRIVS;
691 	return (0);
692 }
693 
694 static int
695 no_new_privs_status(struct thread *td, struct proc *p, void *data)
696 {
697 
698 	*(int *)data = (p->p_flag2 & P2_NO_NEW_PRIVS) != 0 ?
699 	    PROC_NO_NEW_PRIVS_ENABLE : PROC_NO_NEW_PRIVS_DISABLE;
700 	return (0);
701 }
702 
703 static int
704 protmax_ctl(struct thread *td, struct proc *p, void *data)
705 {
706 	int state;
707 
708 	PROC_LOCK_ASSERT(p, MA_OWNED);
709 	state = *(int *)data;
710 
711 	switch (state) {
712 	case PROC_PROTMAX_FORCE_ENABLE:
713 		p->p_flag2 &= ~P2_PROTMAX_DISABLE;
714 		p->p_flag2 |= P2_PROTMAX_ENABLE;
715 		break;
716 	case PROC_PROTMAX_FORCE_DISABLE:
717 		p->p_flag2 |= P2_PROTMAX_DISABLE;
718 		p->p_flag2 &= ~P2_PROTMAX_ENABLE;
719 		break;
720 	case PROC_PROTMAX_NOFORCE:
721 		p->p_flag2 &= ~(P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE);
722 		break;
723 	default:
724 		return (EINVAL);
725 	}
726 	return (0);
727 }
728 
729 static int
730 protmax_status(struct thread *td, struct proc *p, void *data)
731 {
732 	int d;
733 
734 	switch (p->p_flag2 & (P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE)) {
735 	case 0:
736 		d = PROC_PROTMAX_NOFORCE;
737 		break;
738 	case P2_PROTMAX_ENABLE:
739 		d = PROC_PROTMAX_FORCE_ENABLE;
740 		break;
741 	case P2_PROTMAX_DISABLE:
742 		d = PROC_PROTMAX_FORCE_DISABLE;
743 		break;
744 	}
745 	if (kern_mmap_maxprot(p, PROT_READ) == PROT_READ)
746 		d |= PROC_PROTMAX_ACTIVE;
747 	*(int *)data = d;
748 	return (0);
749 }
750 
751 static int
752 aslr_ctl(struct thread *td, struct proc *p, void *data)
753 {
754 	int state;
755 
756 	PROC_LOCK_ASSERT(p, MA_OWNED);
757 	state = *(int *)data;
758 
759 	switch (state) {
760 	case PROC_ASLR_FORCE_ENABLE:
761 		p->p_flag2 &= ~P2_ASLR_DISABLE;
762 		p->p_flag2 |= P2_ASLR_ENABLE;
763 		break;
764 	case PROC_ASLR_FORCE_DISABLE:
765 		p->p_flag2 |= P2_ASLR_DISABLE;
766 		p->p_flag2 &= ~P2_ASLR_ENABLE;
767 		break;
768 	case PROC_ASLR_NOFORCE:
769 		p->p_flag2 &= ~(P2_ASLR_ENABLE | P2_ASLR_DISABLE);
770 		break;
771 	default:
772 		return (EINVAL);
773 	}
774 	return (0);
775 }
776 
777 static int
778 aslr_status(struct thread *td, struct proc *p, void *data)
779 {
780 	struct vmspace *vm;
781 	int d;
782 
783 	switch (p->p_flag2 & (P2_ASLR_ENABLE | P2_ASLR_DISABLE)) {
784 	case 0:
785 		d = PROC_ASLR_NOFORCE;
786 		break;
787 	case P2_ASLR_ENABLE:
788 		d = PROC_ASLR_FORCE_ENABLE;
789 		break;
790 	case P2_ASLR_DISABLE:
791 		d = PROC_ASLR_FORCE_DISABLE;
792 		break;
793 	}
794 	if ((p->p_flag & P_WEXIT) == 0) {
795 		_PHOLD(p);
796 		PROC_UNLOCK(p);
797 		vm = vmspace_acquire_ref(p);
798 		if (vm != NULL) {
799 			if ((vm->vm_map.flags & MAP_ASLR) != 0)
800 				d |= PROC_ASLR_ACTIVE;
801 			vmspace_free(vm);
802 		}
803 		PROC_LOCK(p);
804 		_PRELE(p);
805 	}
806 	*(int *)data = d;
807 	return (0);
808 }
809 
810 static int
811 stackgap_ctl(struct thread *td, struct proc *p, void *data)
812 {
813 	int state;
814 
815 	PROC_LOCK_ASSERT(p, MA_OWNED);
816 	state = *(int *)data;
817 
818 	if ((state & ~(PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE |
819 	    PROC_STACKGAP_ENABLE_EXEC | PROC_STACKGAP_DISABLE_EXEC)) != 0)
820 		return (EINVAL);
821 	switch (state & (PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE)) {
822 	case PROC_STACKGAP_ENABLE:
823 		if ((p->p_flag2 & P2_STKGAP_DISABLE) != 0)
824 			return (EINVAL);
825 		break;
826 	case PROC_STACKGAP_DISABLE:
827 		p->p_flag2 |= P2_STKGAP_DISABLE;
828 		break;
829 	case 0:
830 		break;
831 	default:
832 		return (EINVAL);
833 	}
834 	switch (state & (PROC_STACKGAP_ENABLE_EXEC |
835 	    PROC_STACKGAP_DISABLE_EXEC)) {
836 	case PROC_STACKGAP_ENABLE_EXEC:
837 		p->p_flag2 &= ~P2_STKGAP_DISABLE_EXEC;
838 		break;
839 	case PROC_STACKGAP_DISABLE_EXEC:
840 		p->p_flag2 |= P2_STKGAP_DISABLE_EXEC;
841 		break;
842 	case 0:
843 		break;
844 	default:
845 		return (EINVAL);
846 	}
847 	return (0);
848 }
849 
850 static int
851 stackgap_status(struct thread *td, struct proc *p, void *data)
852 {
853 	int d;
854 
855 	PROC_LOCK_ASSERT(p, MA_OWNED);
856 
857 	d = (p->p_flag2 & P2_STKGAP_DISABLE) != 0 ? PROC_STACKGAP_DISABLE :
858 	    PROC_STACKGAP_ENABLE;
859 	d |= (p->p_flag2 & P2_STKGAP_DISABLE_EXEC) != 0 ?
860 	    PROC_STACKGAP_DISABLE_EXEC : PROC_STACKGAP_ENABLE_EXEC;
861 	*(int *)data = d;
862 	return (0);
863 }
864 
865 static int
866 wxmap_ctl(struct thread *td, struct proc *p, void *data)
867 {
868 	struct vmspace *vm;
869 	vm_map_t map;
870 	int state;
871 
872 	PROC_LOCK_ASSERT(p, MA_OWNED);
873 	if ((p->p_flag & P_WEXIT) != 0)
874 		return (ESRCH);
875 	state = *(int *)data;
876 
877 	switch (state) {
878 	case PROC_WX_MAPPINGS_PERMIT:
879 		p->p_flag2 |= P2_WXORX_DISABLE;
880 		_PHOLD(p);
881 		PROC_UNLOCK(p);
882 		vm = vmspace_acquire_ref(p);
883 		if (vm != NULL) {
884 			map = &vm->vm_map;
885 			vm_map_lock(map);
886 			map->flags &= ~MAP_WXORX;
887 			vm_map_unlock(map);
888 			vmspace_free(vm);
889 		}
890 		PROC_LOCK(p);
891 		_PRELE(p);
892 		break;
893 	case PROC_WX_MAPPINGS_DISALLOW_EXEC:
894 		p->p_flag2 |= P2_WXORX_ENABLE_EXEC;
895 		break;
896 	default:
897 		return (EINVAL);
898 	}
899 
900 	return (0);
901 }
902 
903 static int
904 wxmap_status(struct thread *td, struct proc *p, void *data)
905 {
906 	struct vmspace *vm;
907 	int d;
908 
909 	PROC_LOCK_ASSERT(p, MA_OWNED);
910 	if ((p->p_flag & P_WEXIT) != 0)
911 		return (ESRCH);
912 
913 	d = 0;
914 	if ((p->p_flag2 & P2_WXORX_DISABLE) != 0)
915 		d |= PROC_WX_MAPPINGS_PERMIT;
916 	if ((p->p_flag2 & P2_WXORX_ENABLE_EXEC) != 0)
917 		d |= PROC_WX_MAPPINGS_DISALLOW_EXEC;
918 	_PHOLD(p);
919 	PROC_UNLOCK(p);
920 	vm = vmspace_acquire_ref(p);
921 	if (vm != NULL) {
922 		if ((vm->vm_map.flags & MAP_WXORX) != 0)
923 			d |= PROC_WXORX_ENFORCE;
924 		vmspace_free(vm);
925 	}
926 	PROC_LOCK(p);
927 	_PRELE(p);
928 	*(int *)data = d;
929 	return (0);
930 }
931 
932 static int
933 pdeathsig_ctl(struct thread *td, struct proc *p, void *data)
934 {
935 	int signum;
936 
937 	signum = *(int *)data;
938 	if (p != td->td_proc || (signum != 0 && !_SIG_VALID(signum)))
939 		return (EINVAL);
940 	p->p_pdeathsig = signum;
941 	return (0);
942 }
943 
944 static int
945 pdeathsig_status(struct thread *td, struct proc *p, void *data)
946 {
947 	if (p != td->td_proc)
948 		return (EINVAL);
949 	*(int *)data = p->p_pdeathsig;
950 	return (0);
951 }
952 
953 enum {
954 	PCTL_SLOCKED,
955 	PCTL_XLOCKED,
956 	PCTL_UNLOCKED,
957 };
958 
959 struct procctl_cmd_info {
960 	int lock_tree;
961 	bool one_proc : 1;
962 	bool esrch_is_einval : 1;
963 	bool copyout_on_error : 1;
964 	bool no_nonnull_data : 1;
965 	bool need_candebug : 1;
966 	int copyin_sz;
967 	int copyout_sz;
968 	int (*exec)(struct thread *, struct proc *, void *);
969 	bool (*sapblk)(struct thread *, void *);
970 };
971 static const struct procctl_cmd_info procctl_cmds_info[] = {
972 	[PROC_SPROTECT] =
973 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
974 	      .esrch_is_einval = false, .no_nonnull_data = false,
975 	      .need_candebug = false,
976 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
977 	      .exec = protect_set, .copyout_on_error = false, },
978 	[PROC_REAP_ACQUIRE] =
979 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
980 	      .esrch_is_einval = false, .no_nonnull_data = true,
981 	      .need_candebug = false,
982 	      .copyin_sz = 0, .copyout_sz = 0,
983 	      .exec = reap_acquire, .copyout_on_error = false, },
984 	[PROC_REAP_RELEASE] =
985 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
986 	      .esrch_is_einval = false, .no_nonnull_data = true,
987 	      .need_candebug = false,
988 	      .copyin_sz = 0, .copyout_sz = 0,
989 	      .exec = reap_release, .copyout_on_error = false, },
990 	[PROC_REAP_STATUS] =
991 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
992 	      .esrch_is_einval = false, .no_nonnull_data = false,
993 	      .need_candebug = false,
994 	      .copyin_sz = 0,
995 	      .copyout_sz = sizeof(struct procctl_reaper_status),
996 	      .exec = reap_status, .copyout_on_error = false, },
997 	[PROC_REAP_GETPIDS] =
998 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
999 	      .esrch_is_einval = false, .no_nonnull_data = false,
1000 	      .need_candebug = false,
1001 	      .copyin_sz = sizeof(struct procctl_reaper_pids),
1002 	      .copyout_sz = 0,
1003 	      .exec = reap_getpids, .copyout_on_error = false, },
1004 	[PROC_REAP_KILL] =
1005 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1006 	      .esrch_is_einval = false, .no_nonnull_data = false,
1007 	      .need_candebug = false,
1008 	      .copyin_sz = sizeof(struct procctl_reaper_kill),
1009 	      .copyout_sz = sizeof(struct procctl_reaper_kill),
1010 	      .exec = reap_kill, .copyout_on_error = true,
1011 	      .sapblk = reap_kill_sapblk, },
1012 	[PROC_TRACE_CTL] =
1013 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1014 	      .esrch_is_einval = false, .no_nonnull_data = false,
1015 	      .need_candebug = true,
1016 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1017 	      .exec = trace_ctl, .copyout_on_error = false, },
1018 	[PROC_TRACE_STATUS] =
1019 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1020 	      .esrch_is_einval = false, .no_nonnull_data = false,
1021 	      .need_candebug = false,
1022 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1023 	      .exec = trace_status, .copyout_on_error = false, },
1024 	[PROC_TRAPCAP_CTL] =
1025 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1026 	      .esrch_is_einval = false, .no_nonnull_data = false,
1027 	      .need_candebug = true,
1028 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1029 	      .exec = trapcap_ctl, .copyout_on_error = false, },
1030 	[PROC_TRAPCAP_STATUS] =
1031 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1032 	      .esrch_is_einval = false, .no_nonnull_data = false,
1033 	      .need_candebug = false,
1034 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1035 	      .exec = trapcap_status, .copyout_on_error = false, },
1036 	[PROC_PDEATHSIG_CTL] =
1037 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1038 	      .esrch_is_einval = true, .no_nonnull_data = false,
1039 	      .need_candebug = false,
1040 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1041 	      .exec = pdeathsig_ctl, .copyout_on_error = false, },
1042 	[PROC_PDEATHSIG_STATUS] =
1043 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1044 	      .esrch_is_einval = true, .no_nonnull_data = false,
1045 	      .need_candebug = false,
1046 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1047 	      .exec = pdeathsig_status, .copyout_on_error = false, },
1048 	[PROC_ASLR_CTL] =
1049 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1050 	      .esrch_is_einval = false, .no_nonnull_data = false,
1051 	      .need_candebug = true,
1052 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1053 	      .exec = aslr_ctl, .copyout_on_error = false, },
1054 	[PROC_ASLR_STATUS] =
1055 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1056 	      .esrch_is_einval = false, .no_nonnull_data = false,
1057 	      .need_candebug = false,
1058 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1059 	      .exec = aslr_status, .copyout_on_error = false, },
1060 	[PROC_PROTMAX_CTL] =
1061 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1062 	      .esrch_is_einval = false, .no_nonnull_data = false,
1063 	      .need_candebug = true,
1064 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1065 	      .exec = protmax_ctl, .copyout_on_error = false, },
1066 	[PROC_PROTMAX_STATUS] =
1067 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1068 	      .esrch_is_einval = false, .no_nonnull_data = false,
1069 	      .need_candebug = false,
1070 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1071 	      .exec = protmax_status, .copyout_on_error = false, },
1072 	[PROC_STACKGAP_CTL] =
1073 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1074 	      .esrch_is_einval = false, .no_nonnull_data = false,
1075 	      .need_candebug = true,
1076 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1077 	      .exec = stackgap_ctl, .copyout_on_error = false, },
1078 	[PROC_STACKGAP_STATUS] =
1079 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1080 	      .esrch_is_einval = false, .no_nonnull_data = false,
1081 	      .need_candebug = false,
1082 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1083 	      .exec = stackgap_status, .copyout_on_error = false, },
1084 	[PROC_NO_NEW_PRIVS_CTL] =
1085 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1086 	      .esrch_is_einval = false, .no_nonnull_data = false,
1087 	      .need_candebug = true,
1088 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1089 	      .exec = no_new_privs_ctl, .copyout_on_error = false, },
1090 	[PROC_NO_NEW_PRIVS_STATUS] =
1091 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1092 	      .esrch_is_einval = false, .no_nonnull_data = false,
1093 	      .need_candebug = false,
1094 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1095 	      .exec = no_new_privs_status, .copyout_on_error = false, },
1096 	[PROC_WXMAP_CTL] =
1097 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1098 	      .esrch_is_einval = false, .no_nonnull_data = false,
1099 	      .need_candebug = true,
1100 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1101 	      .exec = wxmap_ctl, .copyout_on_error = false, },
1102 	[PROC_WXMAP_STATUS] =
1103 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1104 	      .esrch_is_einval = false, .no_nonnull_data = false,
1105 	      .need_candebug = false,
1106 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1107 	      .exec = wxmap_status, .copyout_on_error = false, },
1108 };
1109 
1110 int
1111 sys_procctl(struct thread *td, struct procctl_args *uap)
1112 {
1113 	union {
1114 		struct procctl_reaper_status rs;
1115 		struct procctl_reaper_pids rp;
1116 		struct procctl_reaper_kill rk;
1117 		int flags;
1118 	} x;
1119 	const struct procctl_cmd_info *cmd_info;
1120 	int error, error1;
1121 
1122 	if (uap->com >= PROC_PROCCTL_MD_MIN)
1123 		return (cpu_procctl(td, uap->idtype, uap->id,
1124 		    uap->com, uap->data));
1125 	if (uap->com == 0 || uap->com >= nitems(procctl_cmds_info))
1126 		return (EINVAL);
1127 	cmd_info = &procctl_cmds_info[uap->com];
1128 	bzero(&x, sizeof(x));
1129 
1130 	if (cmd_info->copyin_sz > 0) {
1131 		error = copyin(uap->data, &x, cmd_info->copyin_sz);
1132 		if (error != 0)
1133 			return (error);
1134 	} else if (cmd_info->no_nonnull_data && uap->data != NULL) {
1135 		return (EINVAL);
1136 	}
1137 
1138 	error = kern_procctl(td, uap->idtype, uap->id, uap->com, &x);
1139 
1140 	if (cmd_info->copyout_sz > 0 && (error == 0 ||
1141 	    cmd_info->copyout_on_error)) {
1142 		error1 = copyout(&x, uap->data, cmd_info->copyout_sz);
1143 		if (error == 0)
1144 			error = error1;
1145 	}
1146 	return (error);
1147 }
1148 
1149 static int
1150 kern_procctl_single(struct thread *td, struct proc *p, int com, void *data)
1151 {
1152 
1153 	PROC_LOCK_ASSERT(p, MA_OWNED);
1154 	return (procctl_cmds_info[com].exec(td, p, data));
1155 }
1156 
1157 int
1158 kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data)
1159 {
1160 	struct pgrp *pg;
1161 	struct proc *p;
1162 	const struct procctl_cmd_info *cmd_info;
1163 	int error, first_error, ok;
1164 	bool sapblk;
1165 
1166 	MPASS(com > 0 && com < nitems(procctl_cmds_info));
1167 	cmd_info = &procctl_cmds_info[com];
1168 	if (idtype != P_PID && cmd_info->one_proc)
1169 		return (EINVAL);
1170 
1171 	sapblk = false;
1172 	if (cmd_info->sapblk != NULL) {
1173 		sapblk = cmd_info->sapblk(td, data);
1174 		if (sapblk && !stop_all_proc_block())
1175 			return (ERESTART);
1176 	}
1177 
1178 	switch (cmd_info->lock_tree) {
1179 	case PCTL_XLOCKED:
1180 		sx_xlock(&proctree_lock);
1181 		break;
1182 	case PCTL_SLOCKED:
1183 		sx_slock(&proctree_lock);
1184 		break;
1185 	default:
1186 		break;
1187 	}
1188 
1189 	switch (idtype) {
1190 	case P_PID:
1191 		if (id == 0) {
1192 			p = td->td_proc;
1193 			error = 0;
1194 			PROC_LOCK(p);
1195 		} else {
1196 			p = pfind(id);
1197 			if (p == NULL) {
1198 				error = cmd_info->esrch_is_einval ?
1199 				    EINVAL : ESRCH;
1200 				break;
1201 			}
1202 			error = cmd_info->need_candebug ? p_candebug(td, p) :
1203 			    p_cansee(td, p);
1204 		}
1205 		if (error == 0)
1206 			error = kern_procctl_single(td, p, com, data);
1207 		PROC_UNLOCK(p);
1208 		break;
1209 	case P_PGID:
1210 		/*
1211 		 * Attempt to apply the operation to all members of the
1212 		 * group.  Ignore processes in the group that can't be
1213 		 * seen.  Ignore errors so long as at least one process is
1214 		 * able to complete the request successfully.
1215 		 */
1216 		pg = pgfind(id);
1217 		if (pg == NULL) {
1218 			error = ESRCH;
1219 			break;
1220 		}
1221 		PGRP_UNLOCK(pg);
1222 		ok = 0;
1223 		first_error = 0;
1224 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
1225 			PROC_LOCK(p);
1226 			if (p->p_state == PRS_NEW ||
1227 			    p->p_state == PRS_ZOMBIE ||
1228 			    (cmd_info->need_candebug ? p_candebug(td, p) :
1229 			    p_cansee(td, p)) != 0) {
1230 				PROC_UNLOCK(p);
1231 				continue;
1232 			}
1233 			error = kern_procctl_single(td, p, com, data);
1234 			PROC_UNLOCK(p);
1235 			if (error == 0)
1236 				ok = 1;
1237 			else if (first_error == 0)
1238 				first_error = error;
1239 		}
1240 		if (ok)
1241 			error = 0;
1242 		else if (first_error != 0)
1243 			error = first_error;
1244 		else
1245 			/*
1246 			 * Was not able to see any processes in the
1247 			 * process group.
1248 			 */
1249 			error = ESRCH;
1250 		break;
1251 	default:
1252 		error = EINVAL;
1253 		break;
1254 	}
1255 
1256 	switch (cmd_info->lock_tree) {
1257 	case PCTL_XLOCKED:
1258 		sx_xunlock(&proctree_lock);
1259 		break;
1260 	case PCTL_SLOCKED:
1261 		sx_sunlock(&proctree_lock);
1262 		break;
1263 	default:
1264 		break;
1265 	}
1266 	if (sapblk)
1267 		stop_all_proc_unblock();
1268 	return (error);
1269 }
1270