xref: /freebsd/sys/kern/kern_procctl.c (revision 25038e8de6b4e5f2ffca821565b50a633eea499a)
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 "opt_ktrace.h"
31 
32 #include <sys/param.h>
33 #include <sys/_unrhdr.h>
34 #include <sys/systm.h>
35 #include <sys/capsicum.h>
36 #include <sys/lock.h>
37 #include <sys/mman.h>
38 #include <sys/mutex.h>
39 #include <sys/priv.h>
40 #include <sys/proc.h>
41 #include <sys/procctl.h>
42 #include <sys/sx.h>
43 #include <sys/syscallsubr.h>
44 #include <sys/sysproto.h>
45 #include <sys/taskqueue.h>
46 #include <sys/wait.h>
47 
48 #include <vm/vm.h>
49 #include <vm/pmap.h>
50 #include <vm/vm_map.h>
51 #include <vm/vm_extern.h>
52 
53 static int
54 protect_setchild(struct thread *td, struct proc *p, int flags)
55 {
56 
57 	PROC_LOCK_ASSERT(p, MA_OWNED);
58 	if (p->p_flag & P_SYSTEM || p_cansched(td, p) != 0)
59 		return (0);
60 	if (flags & PPROT_SET) {
61 		p->p_flag |= P_PROTECTED;
62 		if (flags & PPROT_INHERIT)
63 			p->p_flag2 |= P2_INHERIT_PROTECTED;
64 	} else {
65 		p->p_flag &= ~P_PROTECTED;
66 		p->p_flag2 &= ~P2_INHERIT_PROTECTED;
67 	}
68 	return (1);
69 }
70 
71 static int
72 protect_setchildren(struct thread *td, struct proc *top, int flags)
73 {
74 	struct proc *p;
75 	int ret;
76 
77 	p = top;
78 	ret = 0;
79 	sx_assert(&proctree_lock, SX_LOCKED);
80 	for (;;) {
81 		ret |= protect_setchild(td, p, flags);
82 		PROC_UNLOCK(p);
83 		/*
84 		 * If this process has children, descend to them next,
85 		 * otherwise do any siblings, and if done with this level,
86 		 * follow back up the tree (but not past top).
87 		 */
88 		if (!LIST_EMPTY(&p->p_children))
89 			p = LIST_FIRST(&p->p_children);
90 		else for (;;) {
91 			if (p == top) {
92 				PROC_LOCK(p);
93 				return (ret);
94 			}
95 			if (LIST_NEXT(p, p_sibling)) {
96 				p = LIST_NEXT(p, p_sibling);
97 				break;
98 			}
99 			p = p->p_pptr;
100 		}
101 		PROC_LOCK(p);
102 	}
103 }
104 
105 static int
106 protect_set(struct thread *td, struct proc *p, void *data)
107 {
108 	int error, flags, ret;
109 
110 	flags = *(int *)data;
111 	switch (PPROT_OP(flags)) {
112 	case PPROT_SET:
113 	case PPROT_CLEAR:
114 		break;
115 	default:
116 		return (EINVAL);
117 	}
118 
119 	if ((PPROT_FLAGS(flags) & ~(PPROT_DESCEND | PPROT_INHERIT)) != 0)
120 		return (EINVAL);
121 
122 	error = priv_check(td, PRIV_VM_MADV_PROTECT);
123 	if (error)
124 		return (error);
125 
126 	if (flags & PPROT_DESCEND)
127 		ret = protect_setchildren(td, p, flags);
128 	else
129 		ret = protect_setchild(td, p, flags);
130 	if (ret == 0)
131 		return (EPERM);
132 	return (0);
133 }
134 
135 static int
136 reap_acquire(struct thread *td, struct proc *p, void *data __unused)
137 {
138 
139 	sx_assert(&proctree_lock, SX_XLOCKED);
140 	if (p != td->td_proc)
141 		return (EPERM);
142 	if ((p->p_treeflag & P_TREE_REAPER) != 0)
143 		return (EBUSY);
144 	p->p_treeflag |= P_TREE_REAPER;
145 	/*
146 	 * We do not reattach existing children and the whole tree
147 	 * under them to us, since p->p_reaper already seen them.
148 	 */
149 	return (0);
150 }
151 
152 static int
153 reap_release(struct thread *td, struct proc *p, void *data __unused)
154 {
155 
156 	sx_assert(&proctree_lock, SX_XLOCKED);
157 	if (p != td->td_proc)
158 		return (EPERM);
159 	if (p == initproc)
160 		return (EINVAL);
161 	if ((p->p_treeflag & P_TREE_REAPER) == 0)
162 		return (EINVAL);
163 	reaper_abandon_children(p, false);
164 	return (0);
165 }
166 
167 static int
168 reap_status(struct thread *td, struct proc *p, void *data)
169 {
170 	struct proc *reap, *p2, *first_p;
171 	struct procctl_reaper_status *rs;
172 
173 	rs = data;
174 	sx_assert(&proctree_lock, SX_LOCKED);
175 	if ((p->p_treeflag & P_TREE_REAPER) == 0) {
176 		reap = p->p_reaper;
177 	} else {
178 		reap = p;
179 		rs->rs_flags |= REAPER_STATUS_OWNED;
180 	}
181 	if (reap == initproc)
182 		rs->rs_flags |= REAPER_STATUS_REALINIT;
183 	rs->rs_reaper = reap->p_pid;
184 	rs->rs_descendants = 0;
185 	rs->rs_children = 0;
186 	if (!LIST_EMPTY(&reap->p_reaplist)) {
187 		first_p = LIST_FIRST(&reap->p_children);
188 		if (first_p == NULL)
189 			first_p = LIST_FIRST(&reap->p_reaplist);
190 		rs->rs_pid = first_p->p_pid;
191 		LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
192 			if (proc_realparent(p2) == reap)
193 				rs->rs_children++;
194 			rs->rs_descendants++;
195 		}
196 	} else {
197 		rs->rs_pid = -1;
198 	}
199 	return (0);
200 }
201 
202 static int
203 reap_getpids(struct thread *td, struct proc *p, void *data)
204 {
205 	struct proc *reap, *p2;
206 	struct procctl_reaper_pidinfo *pi, *pip;
207 	struct procctl_reaper_pids *rp;
208 	u_int i, n;
209 	int error;
210 
211 	rp = data;
212 	sx_assert(&proctree_lock, SX_LOCKED);
213 	PROC_UNLOCK(p);
214 	reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
215 	n = i = 0;
216 	error = 0;
217 	LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling)
218 		n++;
219 	sx_unlock(&proctree_lock);
220 	if (rp->rp_count < n)
221 		n = rp->rp_count;
222 	pi = malloc(n * sizeof(*pi), M_TEMP, M_WAITOK);
223 	sx_slock(&proctree_lock);
224 	LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
225 		if (i == n)
226 			break;
227 		pip = &pi[i];
228 		bzero(pip, sizeof(*pip));
229 		pip->pi_pid = p2->p_pid;
230 		pip->pi_subtree = p2->p_reapsubtree;
231 		pip->pi_flags = REAPER_PIDINFO_VALID;
232 		if (proc_realparent(p2) == reap)
233 			pip->pi_flags |= REAPER_PIDINFO_CHILD;
234 		if ((p2->p_treeflag & P_TREE_REAPER) != 0)
235 			pip->pi_flags |= REAPER_PIDINFO_REAPER;
236 		if ((p2->p_flag & P_STOPPED) != 0)
237 			pip->pi_flags |= REAPER_PIDINFO_STOPPED;
238 		if (p2->p_state == PRS_ZOMBIE)
239 			pip->pi_flags |= REAPER_PIDINFO_ZOMBIE;
240 		else if ((p2->p_flag & P_WEXIT) != 0)
241 			pip->pi_flags |= REAPER_PIDINFO_EXITING;
242 		i++;
243 	}
244 	sx_sunlock(&proctree_lock);
245 	error = copyout(pi, rp->rp_pids, i * sizeof(*pi));
246 	free(pi, M_TEMP);
247 	sx_slock(&proctree_lock);
248 	PROC_LOCK(p);
249 	return (error);
250 }
251 
252 struct reap_kill_proc_work {
253 	struct ucred *cr;
254 	struct proc *target;
255 	ksiginfo_t *ksi;
256 	struct procctl_reaper_kill *rk;
257 	int *error;
258 	struct task t;
259 };
260 
261 static void
262 reap_kill_proc_locked(struct reap_kill_proc_work *w)
263 {
264 	int error1;
265 	bool need_stop;
266 
267 	PROC_LOCK_ASSERT(w->target, MA_OWNED);
268 	PROC_ASSERT_HELD(w->target);
269 
270 	error1 = cr_cansignal(w->cr, w->target, w->rk->rk_sig);
271 	if (error1 != 0) {
272 		if (*w->error == ESRCH) {
273 			w->rk->rk_fpid = w->target->p_pid;
274 			*w->error = error1;
275 		}
276 		return;
277 	}
278 
279 	/*
280 	 * The need_stop indicates if the target process needs to be
281 	 * suspended before being signalled.  This is needed when we
282 	 * guarantee that all processes in subtree are signalled,
283 	 * avoiding the race with some process not yet fully linked
284 	 * into all structures during fork, ignored by iterator, and
285 	 * then escaping signalling.
286 	 *
287 	 * The thread cannot usefully stop itself anyway, and if other
288 	 * thread of the current process forks while the current
289 	 * thread signals the whole subtree, it is an application
290 	 * race.
291 	 */
292 	if ((w->target->p_flag & (P_KPROC | P_SYSTEM | P_STOPPED)) == 0)
293 		need_stop = thread_single(w->target, SINGLE_ALLPROC) == 0;
294 	else
295 		need_stop = false;
296 
297 	(void)pksignal(w->target, w->rk->rk_sig, w->ksi);
298 	w->rk->rk_killed++;
299 	*w->error = error1;
300 
301 	if (need_stop)
302 		thread_single_end(w->target, SINGLE_ALLPROC);
303 }
304 
305 static void
306 reap_kill_proc_work(void *arg, int pending __unused)
307 {
308 	struct reap_kill_proc_work *w;
309 
310 	w = arg;
311 	PROC_LOCK(w->target);
312 	if ((w->target->p_flag2 & P2_WEXIT) == 0)
313 		reap_kill_proc_locked(w);
314 	PROC_UNLOCK(w->target);
315 
316 	sx_xlock(&proctree_lock);
317 	w->target = NULL;
318 	wakeup(&w->target);
319 	sx_xunlock(&proctree_lock);
320 }
321 
322 struct reap_kill_tracker {
323 	struct proc *parent;
324 	TAILQ_ENTRY(reap_kill_tracker) link;
325 };
326 
327 TAILQ_HEAD(reap_kill_tracker_head, reap_kill_tracker);
328 
329 static void
330 reap_kill_sched(struct reap_kill_tracker_head *tracker, struct proc *p2)
331 {
332 	struct reap_kill_tracker *t;
333 
334 	PROC_LOCK(p2);
335 	if ((p2->p_flag2 & P2_WEXIT) != 0) {
336 		PROC_UNLOCK(p2);
337 		return;
338 	}
339 	_PHOLD_LITE(p2);
340 	PROC_UNLOCK(p2);
341 	t = malloc(sizeof(struct reap_kill_tracker), M_TEMP, M_WAITOK);
342 	t->parent = p2;
343 	TAILQ_INSERT_TAIL(tracker, t, link);
344 }
345 
346 static void
347 reap_kill_sched_free(struct reap_kill_tracker *t)
348 {
349 	PRELE(t->parent);
350 	free(t, M_TEMP);
351 }
352 
353 static void
354 reap_kill_children(struct thread *td, struct proc *reaper,
355     struct procctl_reaper_kill *rk, ksiginfo_t *ksi, int *error)
356 {
357 	struct proc *p2;
358 	int error1;
359 
360 	LIST_FOREACH(p2, &reaper->p_children, p_sibling) {
361 		PROC_LOCK(p2);
362 		if ((p2->p_flag2 & P2_WEXIT) == 0) {
363 			error1 = p_cansignal(td, p2, rk->rk_sig);
364 			if (error1 != 0) {
365 				if (*error == ESRCH) {
366 					rk->rk_fpid = p2->p_pid;
367 					*error = error1;
368 				}
369 
370 				/*
371 				 * Do not end the loop on error,
372 				 * signal everything we can.
373 				 */
374 			} else {
375 				(void)pksignal(p2, rk->rk_sig, ksi);
376 				rk->rk_killed++;
377 			}
378 		}
379 		PROC_UNLOCK(p2);
380 	}
381 }
382 
383 static bool
384 reap_kill_subtree_once(struct thread *td, struct proc *p, struct proc *reaper,
385     struct unrhdr *pids, struct reap_kill_proc_work *w)
386 {
387 	struct reap_kill_tracker_head tracker;
388 	struct reap_kill_tracker *t;
389 	struct proc *p2;
390 	int r, xlocked;
391 	bool res, st;
392 
393 	res = false;
394 	TAILQ_INIT(&tracker);
395 	reap_kill_sched(&tracker, reaper);
396 	while ((t = TAILQ_FIRST(&tracker)) != NULL) {
397 		TAILQ_REMOVE(&tracker, t, link);
398 
399 		/*
400 		 * Since reap_kill_proc() drops proctree_lock sx, it
401 		 * is possible that the tracked reaper is no longer.
402 		 * In this case the subtree is reparented to the new
403 		 * reaper, which should handle it.
404 		 */
405 		if ((t->parent->p_treeflag & P_TREE_REAPER) == 0) {
406 			reap_kill_sched_free(t);
407 			res = true;
408 			continue;
409 		}
410 
411 		LIST_FOREACH(p2, &t->parent->p_reaplist, p_reapsibling) {
412 			if (t->parent == reaper &&
413 			    (w->rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
414 			    p2->p_reapsubtree != w->rk->rk_subtree)
415 				continue;
416 			if ((p2->p_treeflag & P_TREE_REAPER) != 0)
417 				reap_kill_sched(&tracker, p2);
418 
419 			/*
420 			 * Handle possible pid reuse.  If we recorded
421 			 * p2 as killed but its p_flag2 does not
422 			 * confirm it, that means that the process
423 			 * terminated and its id was reused by other
424 			 * process in the reaper subtree.
425 			 *
426 			 * Unlocked read of p2->p_flag2 is fine, it is
427 			 * our thread that set the tested flag.
428 			 */
429 			if (alloc_unr_specific(pids, p2->p_pid) != p2->p_pid &&
430 			    (atomic_load_int(&p2->p_flag2) &
431 			    (P2_REAPKILLED | P2_WEXIT)) != 0)
432 				continue;
433 
434 			if (p2 == td->td_proc) {
435 				if ((p2->p_flag & P_HADTHREADS) != 0 &&
436 				    (p2->p_flag2 & P2_WEXIT) == 0) {
437 					xlocked = sx_xlocked(&proctree_lock);
438 					sx_unlock(&proctree_lock);
439 					st = true;
440 				} else {
441 					st = false;
442 				}
443 				PROC_LOCK(p2);
444 				/*
445 				 * sapblk ensures that only one thread
446 				 * in the system sets this flag.
447 				 */
448 				p2->p_flag2 |= P2_REAPKILLED;
449 				if (st)
450 					r = thread_single(p2, SINGLE_NO_EXIT);
451 				(void)pksignal(p2, w->rk->rk_sig, w->ksi);
452 				w->rk->rk_killed++;
453 				if (st && r == 0)
454 					thread_single_end(p2, SINGLE_NO_EXIT);
455 				PROC_UNLOCK(p2);
456 				if (st) {
457 					if (xlocked)
458 						sx_xlock(&proctree_lock);
459 					else
460 						sx_slock(&proctree_lock);
461 				}
462 			} else {
463 				PROC_LOCK(p2);
464 				if ((p2->p_flag2 & P2_WEXIT) == 0) {
465 					_PHOLD_LITE(p2);
466 					p2->p_flag2 |= P2_REAPKILLED;
467 					PROC_UNLOCK(p2);
468 					w->target = p2;
469 					taskqueue_enqueue(taskqueue_thread,
470 					    &w->t);
471 					while (w->target != NULL) {
472 						sx_sleep(&w->target,
473 						    &proctree_lock, PWAIT,
474 						    "reapst", 0);
475 					}
476 					PROC_LOCK(p2);
477 					_PRELE(p2);
478 				}
479 				PROC_UNLOCK(p2);
480 			}
481 			res = true;
482 		}
483 		reap_kill_sched_free(t);
484 	}
485 	return (res);
486 }
487 
488 static void
489 reap_kill_subtree(struct thread *td, struct proc *p, struct proc *reaper,
490     struct reap_kill_proc_work *w)
491 {
492 	struct unrhdr pids;
493 	void *ihandle;
494 	struct proc *p2;
495 	int pid;
496 
497 	/*
498 	 * pids records processes which were already signalled, to
499 	 * avoid doubling signals to them if iteration needs to be
500 	 * repeated.
501 	 */
502 	init_unrhdr(&pids, 1, PID_MAX, UNR_NO_MTX);
503 	PROC_LOCK(td->td_proc);
504 	if ((td->td_proc->p_flag2 & P2_WEXIT) != 0) {
505 		PROC_UNLOCK(td->td_proc);
506 		goto out;
507 	}
508 	PROC_UNLOCK(td->td_proc);
509 	while (reap_kill_subtree_once(td, p, reaper, &pids, w))
510 	       ;
511 
512 	ihandle = create_iter_unr(&pids);
513 	while ((pid = next_iter_unr(ihandle)) != -1) {
514 		p2 = pfind(pid);
515 		if (p2 != NULL) {
516 			p2->p_flag2 &= ~P2_REAPKILLED;
517 			PROC_UNLOCK(p2);
518 		}
519 	}
520 	free_iter_unr(ihandle);
521 
522 out:
523 	clean_unrhdr(&pids);
524 	clear_unrhdr(&pids);
525 }
526 
527 static bool
528 reap_kill_sapblk(struct thread *td __unused, void *data)
529 {
530 	struct procctl_reaper_kill *rk;
531 
532 	rk = data;
533 	return ((rk->rk_flags & REAPER_KILL_CHILDREN) == 0);
534 }
535 
536 static int
537 reap_kill(struct thread *td, struct proc *p, void *data)
538 {
539 	struct reap_kill_proc_work w;
540 	struct proc *reaper;
541 	ksiginfo_t ksi;
542 	struct procctl_reaper_kill *rk;
543 	int error;
544 
545 	rk = data;
546 	sx_assert(&proctree_lock, SX_LOCKED);
547 	if (CAP_TRACING(td))
548 		ktrcapfail(CAPFAIL_SIGNAL, &rk->rk_sig);
549 	if (IN_CAPABILITY_MODE(td))
550 		return (ECAPMODE);
551 	if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG ||
552 	    (rk->rk_flags & ~(REAPER_KILL_CHILDREN |
553 	    REAPER_KILL_SUBTREE)) != 0 || (rk->rk_flags &
554 	    (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE)) ==
555 	    (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE))
556 		return (EINVAL);
557 	PROC_UNLOCK(p);
558 	reaper = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
559 	ksiginfo_init(&ksi);
560 	ksi.ksi_signo = rk->rk_sig;
561 	ksi.ksi_code = SI_USER;
562 	ksi.ksi_pid = td->td_proc->p_pid;
563 	ksi.ksi_uid = td->td_ucred->cr_ruid;
564 	error = ESRCH;
565 	rk->rk_killed = 0;
566 	rk->rk_fpid = -1;
567 	if ((rk->rk_flags & REAPER_KILL_CHILDREN) != 0) {
568 		reap_kill_children(td, reaper, rk, &ksi, &error);
569 	} else {
570 		w.cr = crhold(td->td_ucred);
571 		w.ksi = &ksi;
572 		w.rk = rk;
573 		w.error = &error;
574 		TASK_INIT(&w.t, 0, reap_kill_proc_work, &w);
575 
576 		/*
577 		 * Prevent swapout, since w, ksi, and possibly rk, are
578 		 * allocated on the stack.  We sleep in
579 		 * reap_kill_subtree_once() waiting for task to
580 		 * complete single-threading.
581 		 */
582 		PHOLD(td->td_proc);
583 
584 		reap_kill_subtree(td, p, reaper, &w);
585 		PRELE(td->td_proc);
586 		crfree(w.cr);
587 	}
588 	PROC_LOCK(p);
589 	return (error);
590 }
591 
592 static int
593 trace_ctl(struct thread *td, struct proc *p, void *data)
594 {
595 	int state;
596 
597 	PROC_LOCK_ASSERT(p, MA_OWNED);
598 	state = *(int *)data;
599 
600 	/*
601 	 * Ktrace changes p_traceflag from or to zero under the
602 	 * process lock, so the test does not need to acquire ktrace
603 	 * mutex.
604 	 */
605 	if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0)
606 		return (EBUSY);
607 
608 	switch (state) {
609 	case PROC_TRACE_CTL_ENABLE:
610 		if (td->td_proc != p)
611 			return (EPERM);
612 		p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC);
613 		break;
614 	case PROC_TRACE_CTL_DISABLE_EXEC:
615 		p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE;
616 		break;
617 	case PROC_TRACE_CTL_DISABLE:
618 		if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) {
619 			KASSERT((p->p_flag2 & P2_NOTRACE) != 0,
620 			    ("dandling P2_NOTRACE_EXEC"));
621 			if (td->td_proc != p)
622 				return (EPERM);
623 			p->p_flag2 &= ~P2_NOTRACE_EXEC;
624 		} else {
625 			p->p_flag2 |= P2_NOTRACE;
626 		}
627 		break;
628 	default:
629 		return (EINVAL);
630 	}
631 	return (0);
632 }
633 
634 static int
635 trace_status(struct thread *td, struct proc *p, void *data)
636 {
637 	int *status;
638 
639 	status = data;
640 	if ((p->p_flag2 & P2_NOTRACE) != 0) {
641 		KASSERT((p->p_flag & P_TRACED) == 0,
642 		    ("%d traced but tracing disabled", p->p_pid));
643 		*status = -1;
644 	} else if ((p->p_flag & P_TRACED) != 0) {
645 		*status = p->p_pptr->p_pid;
646 	} else {
647 		*status = 0;
648 	}
649 	return (0);
650 }
651 
652 static int
653 trapcap_ctl(struct thread *td, struct proc *p, void *data)
654 {
655 	int state;
656 
657 	PROC_LOCK_ASSERT(p, MA_OWNED);
658 	state = *(int *)data;
659 
660 	switch (state) {
661 	case PROC_TRAPCAP_CTL_ENABLE:
662 		p->p_flag2 |= P2_TRAPCAP;
663 		break;
664 	case PROC_TRAPCAP_CTL_DISABLE:
665 		p->p_flag2 &= ~P2_TRAPCAP;
666 		break;
667 	default:
668 		return (EINVAL);
669 	}
670 	return (0);
671 }
672 
673 static int
674 trapcap_status(struct thread *td, struct proc *p, void *data)
675 {
676 	int *status;
677 
678 	status = data;
679 	*status = (p->p_flag2 & P2_TRAPCAP) != 0 ? PROC_TRAPCAP_CTL_ENABLE :
680 	    PROC_TRAPCAP_CTL_DISABLE;
681 	return (0);
682 }
683 
684 static int
685 no_new_privs_ctl(struct thread *td, struct proc *p, void *data)
686 {
687 	int state;
688 
689 	PROC_LOCK_ASSERT(p, MA_OWNED);
690 	state = *(int *)data;
691 
692 	if (state != PROC_NO_NEW_PRIVS_ENABLE)
693 		return (EINVAL);
694 	p->p_flag2 |= P2_NO_NEW_PRIVS;
695 	return (0);
696 }
697 
698 static int
699 no_new_privs_status(struct thread *td, struct proc *p, void *data)
700 {
701 
702 	*(int *)data = (p->p_flag2 & P2_NO_NEW_PRIVS) != 0 ?
703 	    PROC_NO_NEW_PRIVS_ENABLE : PROC_NO_NEW_PRIVS_DISABLE;
704 	return (0);
705 }
706 
707 static int
708 protmax_ctl(struct thread *td, struct proc *p, void *data)
709 {
710 	int state;
711 
712 	PROC_LOCK_ASSERT(p, MA_OWNED);
713 	state = *(int *)data;
714 
715 	switch (state) {
716 	case PROC_PROTMAX_FORCE_ENABLE:
717 		p->p_flag2 &= ~P2_PROTMAX_DISABLE;
718 		p->p_flag2 |= P2_PROTMAX_ENABLE;
719 		break;
720 	case PROC_PROTMAX_FORCE_DISABLE:
721 		p->p_flag2 |= P2_PROTMAX_DISABLE;
722 		p->p_flag2 &= ~P2_PROTMAX_ENABLE;
723 		break;
724 	case PROC_PROTMAX_NOFORCE:
725 		p->p_flag2 &= ~(P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE);
726 		break;
727 	default:
728 		return (EINVAL);
729 	}
730 	return (0);
731 }
732 
733 static int
734 protmax_status(struct thread *td, struct proc *p, void *data)
735 {
736 	int d;
737 
738 	switch (p->p_flag2 & (P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE)) {
739 	case 0:
740 		d = PROC_PROTMAX_NOFORCE;
741 		break;
742 	case P2_PROTMAX_ENABLE:
743 		d = PROC_PROTMAX_FORCE_ENABLE;
744 		break;
745 	case P2_PROTMAX_DISABLE:
746 		d = PROC_PROTMAX_FORCE_DISABLE;
747 		break;
748 	}
749 	if (kern_mmap_maxprot(p, PROT_READ) == PROT_READ)
750 		d |= PROC_PROTMAX_ACTIVE;
751 	*(int *)data = d;
752 	return (0);
753 }
754 
755 static int
756 aslr_ctl(struct thread *td, struct proc *p, void *data)
757 {
758 	int state;
759 
760 	PROC_LOCK_ASSERT(p, MA_OWNED);
761 	state = *(int *)data;
762 
763 	switch (state) {
764 	case PROC_ASLR_FORCE_ENABLE:
765 		p->p_flag2 &= ~P2_ASLR_DISABLE;
766 		p->p_flag2 |= P2_ASLR_ENABLE;
767 		break;
768 	case PROC_ASLR_FORCE_DISABLE:
769 		p->p_flag2 |= P2_ASLR_DISABLE;
770 		p->p_flag2 &= ~P2_ASLR_ENABLE;
771 		break;
772 	case PROC_ASLR_NOFORCE:
773 		p->p_flag2 &= ~(P2_ASLR_ENABLE | P2_ASLR_DISABLE);
774 		break;
775 	default:
776 		return (EINVAL);
777 	}
778 	return (0);
779 }
780 
781 static int
782 aslr_status(struct thread *td, struct proc *p, void *data)
783 {
784 	struct vmspace *vm;
785 	int d;
786 
787 	switch (p->p_flag2 & (P2_ASLR_ENABLE | P2_ASLR_DISABLE)) {
788 	case 0:
789 		d = PROC_ASLR_NOFORCE;
790 		break;
791 	case P2_ASLR_ENABLE:
792 		d = PROC_ASLR_FORCE_ENABLE;
793 		break;
794 	case P2_ASLR_DISABLE:
795 		d = PROC_ASLR_FORCE_DISABLE;
796 		break;
797 	}
798 	if ((p->p_flag & P_WEXIT) == 0) {
799 		_PHOLD(p);
800 		PROC_UNLOCK(p);
801 		vm = vmspace_acquire_ref(p);
802 		if (vm != NULL) {
803 			if ((vm->vm_map.flags & MAP_ASLR) != 0)
804 				d |= PROC_ASLR_ACTIVE;
805 			vmspace_free(vm);
806 		}
807 		PROC_LOCK(p);
808 		_PRELE(p);
809 	}
810 	*(int *)data = d;
811 	return (0);
812 }
813 
814 static int
815 stackgap_ctl(struct thread *td, struct proc *p, void *data)
816 {
817 	int state;
818 
819 	PROC_LOCK_ASSERT(p, MA_OWNED);
820 	state = *(int *)data;
821 
822 	if ((state & ~(PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE |
823 	    PROC_STACKGAP_ENABLE_EXEC | PROC_STACKGAP_DISABLE_EXEC)) != 0)
824 		return (EINVAL);
825 	switch (state & (PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE)) {
826 	case PROC_STACKGAP_ENABLE:
827 		if ((p->p_flag2 & P2_STKGAP_DISABLE) != 0)
828 			return (EINVAL);
829 		break;
830 	case PROC_STACKGAP_DISABLE:
831 		p->p_flag2 |= P2_STKGAP_DISABLE;
832 		break;
833 	case 0:
834 		break;
835 	default:
836 		return (EINVAL);
837 	}
838 	switch (state & (PROC_STACKGAP_ENABLE_EXEC |
839 	    PROC_STACKGAP_DISABLE_EXEC)) {
840 	case PROC_STACKGAP_ENABLE_EXEC:
841 		p->p_flag2 &= ~P2_STKGAP_DISABLE_EXEC;
842 		break;
843 	case PROC_STACKGAP_DISABLE_EXEC:
844 		p->p_flag2 |= P2_STKGAP_DISABLE_EXEC;
845 		break;
846 	case 0:
847 		break;
848 	default:
849 		return (EINVAL);
850 	}
851 	return (0);
852 }
853 
854 static int
855 stackgap_status(struct thread *td, struct proc *p, void *data)
856 {
857 	int d;
858 
859 	PROC_LOCK_ASSERT(p, MA_OWNED);
860 
861 	d = (p->p_flag2 & P2_STKGAP_DISABLE) != 0 ? PROC_STACKGAP_DISABLE :
862 	    PROC_STACKGAP_ENABLE;
863 	d |= (p->p_flag2 & P2_STKGAP_DISABLE_EXEC) != 0 ?
864 	    PROC_STACKGAP_DISABLE_EXEC : PROC_STACKGAP_ENABLE_EXEC;
865 	*(int *)data = d;
866 	return (0);
867 }
868 
869 static int
870 wxmap_ctl(struct thread *td, struct proc *p, void *data)
871 {
872 	struct vmspace *vm;
873 	vm_map_t map;
874 	int state;
875 
876 	PROC_LOCK_ASSERT(p, MA_OWNED);
877 	if ((p->p_flag & P_WEXIT) != 0)
878 		return (ESRCH);
879 	state = *(int *)data;
880 
881 	switch (state) {
882 	case PROC_WX_MAPPINGS_PERMIT:
883 		p->p_flag2 |= P2_WXORX_DISABLE;
884 		_PHOLD(p);
885 		PROC_UNLOCK(p);
886 		vm = vmspace_acquire_ref(p);
887 		if (vm != NULL) {
888 			map = &vm->vm_map;
889 			vm_map_lock(map);
890 			map->flags &= ~MAP_WXORX;
891 			vm_map_unlock(map);
892 			vmspace_free(vm);
893 		}
894 		PROC_LOCK(p);
895 		_PRELE(p);
896 		break;
897 	case PROC_WX_MAPPINGS_DISALLOW_EXEC:
898 		p->p_flag2 |= P2_WXORX_ENABLE_EXEC;
899 		break;
900 	default:
901 		return (EINVAL);
902 	}
903 
904 	return (0);
905 }
906 
907 static int
908 wxmap_status(struct thread *td, struct proc *p, void *data)
909 {
910 	struct vmspace *vm;
911 	int d;
912 
913 	PROC_LOCK_ASSERT(p, MA_OWNED);
914 	if ((p->p_flag & P_WEXIT) != 0)
915 		return (ESRCH);
916 
917 	d = 0;
918 	if ((p->p_flag2 & P2_WXORX_DISABLE) != 0)
919 		d |= PROC_WX_MAPPINGS_PERMIT;
920 	if ((p->p_flag2 & P2_WXORX_ENABLE_EXEC) != 0)
921 		d |= PROC_WX_MAPPINGS_DISALLOW_EXEC;
922 	_PHOLD(p);
923 	PROC_UNLOCK(p);
924 	vm = vmspace_acquire_ref(p);
925 	if (vm != NULL) {
926 		if ((vm->vm_map.flags & MAP_WXORX) != 0)
927 			d |= PROC_WXORX_ENFORCE;
928 		vmspace_free(vm);
929 	}
930 	PROC_LOCK(p);
931 	_PRELE(p);
932 	*(int *)data = d;
933 	return (0);
934 }
935 
936 static int
937 pdeathsig_ctl(struct thread *td, struct proc *p, void *data)
938 {
939 	int signum;
940 
941 	signum = *(int *)data;
942 	if (p != td->td_proc || (signum != 0 && !_SIG_VALID(signum)))
943 		return (EINVAL);
944 	p->p_pdeathsig = signum;
945 	return (0);
946 }
947 
948 static int
949 pdeathsig_status(struct thread *td, struct proc *p, void *data)
950 {
951 	if (p != td->td_proc)
952 		return (EINVAL);
953 	*(int *)data = p->p_pdeathsig;
954 	return (0);
955 }
956 
957 enum {
958 	PCTL_SLOCKED,
959 	PCTL_XLOCKED,
960 	PCTL_UNLOCKED,
961 };
962 
963 struct procctl_cmd_info {
964 	int lock_tree;
965 	bool one_proc : 1;
966 	bool esrch_is_einval : 1;
967 	bool copyout_on_error : 1;
968 	bool no_nonnull_data : 1;
969 	bool need_candebug : 1;
970 	int copyin_sz;
971 	int copyout_sz;
972 	int (*exec)(struct thread *, struct proc *, void *);
973 	bool (*sapblk)(struct thread *, void *);
974 };
975 static const struct procctl_cmd_info procctl_cmds_info[] = {
976 	[PROC_SPROTECT] =
977 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
978 	      .esrch_is_einval = false, .no_nonnull_data = false,
979 	      .need_candebug = false,
980 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
981 	      .exec = protect_set, .copyout_on_error = false, },
982 	[PROC_REAP_ACQUIRE] =
983 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
984 	      .esrch_is_einval = false, .no_nonnull_data = true,
985 	      .need_candebug = false,
986 	      .copyin_sz = 0, .copyout_sz = 0,
987 	      .exec = reap_acquire, .copyout_on_error = false, },
988 	[PROC_REAP_RELEASE] =
989 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
990 	      .esrch_is_einval = false, .no_nonnull_data = true,
991 	      .need_candebug = false,
992 	      .copyin_sz = 0, .copyout_sz = 0,
993 	      .exec = reap_release, .copyout_on_error = false, },
994 	[PROC_REAP_STATUS] =
995 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
996 	      .esrch_is_einval = false, .no_nonnull_data = false,
997 	      .need_candebug = false,
998 	      .copyin_sz = 0,
999 	      .copyout_sz = sizeof(struct procctl_reaper_status),
1000 	      .exec = reap_status, .copyout_on_error = false, },
1001 	[PROC_REAP_GETPIDS] =
1002 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1003 	      .esrch_is_einval = false, .no_nonnull_data = false,
1004 	      .need_candebug = false,
1005 	      .copyin_sz = sizeof(struct procctl_reaper_pids),
1006 	      .copyout_sz = 0,
1007 	      .exec = reap_getpids, .copyout_on_error = false, },
1008 	[PROC_REAP_KILL] =
1009 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1010 	      .esrch_is_einval = false, .no_nonnull_data = false,
1011 	      .need_candebug = false,
1012 	      .copyin_sz = sizeof(struct procctl_reaper_kill),
1013 	      .copyout_sz = sizeof(struct procctl_reaper_kill),
1014 	      .exec = reap_kill, .copyout_on_error = true,
1015 	      .sapblk = reap_kill_sapblk, },
1016 	[PROC_TRACE_CTL] =
1017 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1018 	      .esrch_is_einval = false, .no_nonnull_data = false,
1019 	      .need_candebug = true,
1020 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1021 	      .exec = trace_ctl, .copyout_on_error = false, },
1022 	[PROC_TRACE_STATUS] =
1023 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1024 	      .esrch_is_einval = false, .no_nonnull_data = false,
1025 	      .need_candebug = false,
1026 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1027 	      .exec = trace_status, .copyout_on_error = false, },
1028 	[PROC_TRAPCAP_CTL] =
1029 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1030 	      .esrch_is_einval = false, .no_nonnull_data = false,
1031 	      .need_candebug = true,
1032 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1033 	      .exec = trapcap_ctl, .copyout_on_error = false, },
1034 	[PROC_TRAPCAP_STATUS] =
1035 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1036 	      .esrch_is_einval = false, .no_nonnull_data = false,
1037 	      .need_candebug = false,
1038 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1039 	      .exec = trapcap_status, .copyout_on_error = false, },
1040 	[PROC_PDEATHSIG_CTL] =
1041 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1042 	      .esrch_is_einval = true, .no_nonnull_data = false,
1043 	      .need_candebug = false,
1044 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1045 	      .exec = pdeathsig_ctl, .copyout_on_error = false, },
1046 	[PROC_PDEATHSIG_STATUS] =
1047 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1048 	      .esrch_is_einval = true, .no_nonnull_data = false,
1049 	      .need_candebug = false,
1050 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1051 	      .exec = pdeathsig_status, .copyout_on_error = false, },
1052 	[PROC_ASLR_CTL] =
1053 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1054 	      .esrch_is_einval = false, .no_nonnull_data = false,
1055 	      .need_candebug = true,
1056 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1057 	      .exec = aslr_ctl, .copyout_on_error = false, },
1058 	[PROC_ASLR_STATUS] =
1059 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1060 	      .esrch_is_einval = false, .no_nonnull_data = false,
1061 	      .need_candebug = false,
1062 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1063 	      .exec = aslr_status, .copyout_on_error = false, },
1064 	[PROC_PROTMAX_CTL] =
1065 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1066 	      .esrch_is_einval = false, .no_nonnull_data = false,
1067 	      .need_candebug = true,
1068 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1069 	      .exec = protmax_ctl, .copyout_on_error = false, },
1070 	[PROC_PROTMAX_STATUS] =
1071 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1072 	      .esrch_is_einval = false, .no_nonnull_data = false,
1073 	      .need_candebug = false,
1074 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1075 	      .exec = protmax_status, .copyout_on_error = false, },
1076 	[PROC_STACKGAP_CTL] =
1077 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1078 	      .esrch_is_einval = false, .no_nonnull_data = false,
1079 	      .need_candebug = true,
1080 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1081 	      .exec = stackgap_ctl, .copyout_on_error = false, },
1082 	[PROC_STACKGAP_STATUS] =
1083 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1084 	      .esrch_is_einval = false, .no_nonnull_data = false,
1085 	      .need_candebug = false,
1086 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1087 	      .exec = stackgap_status, .copyout_on_error = false, },
1088 	[PROC_NO_NEW_PRIVS_CTL] =
1089 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1090 	      .esrch_is_einval = false, .no_nonnull_data = false,
1091 	      .need_candebug = true,
1092 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1093 	      .exec = no_new_privs_ctl, .copyout_on_error = false, },
1094 	[PROC_NO_NEW_PRIVS_STATUS] =
1095 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1096 	      .esrch_is_einval = false, .no_nonnull_data = false,
1097 	      .need_candebug = false,
1098 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1099 	      .exec = no_new_privs_status, .copyout_on_error = false, },
1100 	[PROC_WXMAP_CTL] =
1101 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1102 	      .esrch_is_einval = false, .no_nonnull_data = false,
1103 	      .need_candebug = true,
1104 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1105 	      .exec = wxmap_ctl, .copyout_on_error = false, },
1106 	[PROC_WXMAP_STATUS] =
1107 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1108 	      .esrch_is_einval = false, .no_nonnull_data = false,
1109 	      .need_candebug = false,
1110 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1111 	      .exec = wxmap_status, .copyout_on_error = false, },
1112 };
1113 
1114 int
1115 sys_procctl(struct thread *td, struct procctl_args *uap)
1116 {
1117 	union {
1118 		struct procctl_reaper_status rs;
1119 		struct procctl_reaper_pids rp;
1120 		struct procctl_reaper_kill rk;
1121 		int flags;
1122 	} x;
1123 	const struct procctl_cmd_info *cmd_info;
1124 	int error, error1;
1125 
1126 	if (uap->com >= PROC_PROCCTL_MD_MIN)
1127 		return (cpu_procctl(td, uap->idtype, uap->id,
1128 		    uap->com, uap->data));
1129 	if (uap->com <= 0 || uap->com >= nitems(procctl_cmds_info))
1130 		return (EINVAL);
1131 	cmd_info = &procctl_cmds_info[uap->com];
1132 	bzero(&x, sizeof(x));
1133 
1134 	if (cmd_info->copyin_sz > 0) {
1135 		error = copyin(uap->data, &x, cmd_info->copyin_sz);
1136 		if (error != 0)
1137 			return (error);
1138 	} else if (cmd_info->no_nonnull_data && uap->data != NULL) {
1139 		return (EINVAL);
1140 	}
1141 
1142 	error = kern_procctl(td, uap->idtype, uap->id, uap->com, &x);
1143 
1144 	if (cmd_info->copyout_sz > 0 && (error == 0 ||
1145 	    cmd_info->copyout_on_error)) {
1146 		error1 = copyout(&x, uap->data, cmd_info->copyout_sz);
1147 		if (error == 0)
1148 			error = error1;
1149 	}
1150 	return (error);
1151 }
1152 
1153 static int
1154 kern_procctl_single(struct thread *td, struct proc *p, int com, void *data)
1155 {
1156 
1157 	PROC_LOCK_ASSERT(p, MA_OWNED);
1158 	return (procctl_cmds_info[com].exec(td, p, data));
1159 }
1160 
1161 int
1162 kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data)
1163 {
1164 	struct pgrp *pg;
1165 	struct proc *p;
1166 	const struct procctl_cmd_info *cmd_info;
1167 	int error, first_error, ok;
1168 	bool sapblk;
1169 
1170 	MPASS(com > 0 && com < nitems(procctl_cmds_info));
1171 	cmd_info = &procctl_cmds_info[com];
1172 	if (idtype != P_PID && cmd_info->one_proc)
1173 		return (EINVAL);
1174 
1175 	sapblk = false;
1176 	if (cmd_info->sapblk != NULL) {
1177 		sapblk = cmd_info->sapblk(td, data);
1178 		if (sapblk && !stop_all_proc_block())
1179 			return (ERESTART);
1180 	}
1181 
1182 	switch (cmd_info->lock_tree) {
1183 	case PCTL_XLOCKED:
1184 		sx_xlock(&proctree_lock);
1185 		break;
1186 	case PCTL_SLOCKED:
1187 		sx_slock(&proctree_lock);
1188 		break;
1189 	default:
1190 		break;
1191 	}
1192 
1193 	switch (idtype) {
1194 	case P_PID:
1195 		if (id == 0) {
1196 			p = td->td_proc;
1197 			error = 0;
1198 			PROC_LOCK(p);
1199 		} else {
1200 			p = pfind(id);
1201 			if (p == NULL) {
1202 				error = cmd_info->esrch_is_einval ?
1203 				    EINVAL : ESRCH;
1204 				break;
1205 			}
1206 			error = cmd_info->need_candebug ? p_candebug(td, p) :
1207 			    p_cansee(td, p);
1208 		}
1209 		if (error == 0)
1210 			error = kern_procctl_single(td, p, com, data);
1211 		PROC_UNLOCK(p);
1212 		break;
1213 	case P_PGID:
1214 		/*
1215 		 * Attempt to apply the operation to all members of the
1216 		 * group.  Ignore processes in the group that can't be
1217 		 * seen.  Ignore errors so long as at least one process is
1218 		 * able to complete the request successfully.
1219 		 */
1220 		pg = pgfind(id);
1221 		if (pg == NULL) {
1222 			error = ESRCH;
1223 			break;
1224 		}
1225 		PGRP_UNLOCK(pg);
1226 		ok = 0;
1227 		first_error = 0;
1228 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
1229 			PROC_LOCK(p);
1230 			if (p->p_state == PRS_NEW ||
1231 			    p->p_state == PRS_ZOMBIE ||
1232 			    (cmd_info->need_candebug ? p_candebug(td, p) :
1233 			    p_cansee(td, p)) != 0) {
1234 				PROC_UNLOCK(p);
1235 				continue;
1236 			}
1237 			error = kern_procctl_single(td, p, com, data);
1238 			PROC_UNLOCK(p);
1239 			if (error == 0)
1240 				ok = 1;
1241 			else if (first_error == 0)
1242 				first_error = error;
1243 		}
1244 		if (ok)
1245 			error = 0;
1246 		else if (first_error != 0)
1247 			error = first_error;
1248 		else
1249 			/*
1250 			 * Was not able to see any processes in the
1251 			 * process group.
1252 			 */
1253 			error = ESRCH;
1254 		break;
1255 	default:
1256 		error = EINVAL;
1257 		break;
1258 	}
1259 
1260 	switch (cmd_info->lock_tree) {
1261 	case PCTL_XLOCKED:
1262 		sx_xunlock(&proctree_lock);
1263 		break;
1264 	case PCTL_SLOCKED:
1265 		sx_sunlock(&proctree_lock);
1266 		break;
1267 	default:
1268 		break;
1269 	}
1270 	if (sapblk)
1271 		stop_all_proc_unblock();
1272 	return (error);
1273 }
1274