xref: /freebsd/sys/kern/kern_procctl.c (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
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/malloc.h>
38 #include <sys/mman.h>
39 #include <sys/mutex.h>
40 #include <sys/priv.h>
41 #include <sys/proc.h>
42 #include <sys/procctl.h>
43 #include <sys/sx.h>
44 #include <sys/syscallsubr.h>
45 #include <sys/sysproto.h>
46 #include <sys/taskqueue.h>
47 #include <sys/wait.h>
48 
49 #include <vm/vm.h>
50 #include <vm/pmap.h>
51 #include <vm/vm_map.h>
52 #include <vm/vm_extern.h>
53 
54 static int
55 protect_setchild(struct thread *td, struct proc *p, int flags)
56 {
57 
58 	PROC_LOCK_ASSERT(p, MA_OWNED);
59 	if (p->p_flag & P_SYSTEM || p_cansched(td, p) != 0)
60 		return (0);
61 	if (flags & PPROT_SET) {
62 		p->p_flag |= P_PROTECTED;
63 		if (flags & PPROT_INHERIT)
64 			p->p_flag2 |= P2_INHERIT_PROTECTED;
65 	} else {
66 		p->p_flag &= ~P_PROTECTED;
67 		p->p_flag2 &= ~P2_INHERIT_PROTECTED;
68 	}
69 	return (1);
70 }
71 
72 static int
73 protect_setchildren(struct thread *td, struct proc *top, int flags)
74 {
75 	struct proc *p;
76 	int ret;
77 
78 	p = top;
79 	ret = 0;
80 	sx_assert(&proctree_lock, SX_LOCKED);
81 	for (;;) {
82 		ret |= protect_setchild(td, p, flags);
83 		PROC_UNLOCK(p);
84 		/*
85 		 * If this process has children, descend to them next,
86 		 * otherwise do any siblings, and if done with this level,
87 		 * follow back up the tree (but not past top).
88 		 */
89 		if (!LIST_EMPTY(&p->p_children))
90 			p = LIST_FIRST(&p->p_children);
91 		else for (;;) {
92 			if (p == top) {
93 				PROC_LOCK(p);
94 				return (ret);
95 			}
96 			if (LIST_NEXT(p, p_sibling)) {
97 				p = LIST_NEXT(p, p_sibling);
98 				break;
99 			}
100 			p = p->p_pptr;
101 		}
102 		PROC_LOCK(p);
103 	}
104 }
105 
106 static int
107 protect_set(struct thread *td, struct proc *p, void *data)
108 {
109 	int error, flags, ret;
110 
111 	flags = *(int *)data;
112 	switch (PPROT_OP(flags)) {
113 	case PPROT_SET:
114 	case PPROT_CLEAR:
115 		break;
116 	default:
117 		return (EINVAL);
118 	}
119 
120 	if ((PPROT_FLAGS(flags) & ~(PPROT_DESCEND | PPROT_INHERIT)) != 0)
121 		return (EINVAL);
122 
123 	error = priv_check(td, PRIV_VM_MADV_PROTECT);
124 	if (error)
125 		return (error);
126 
127 	if (flags & PPROT_DESCEND)
128 		ret = protect_setchildren(td, p, flags);
129 	else
130 		ret = protect_setchild(td, p, flags);
131 	if (ret == 0)
132 		return (EPERM);
133 	return (0);
134 }
135 
136 static int
137 reap_acquire(struct thread *td, struct proc *p, void *data __unused)
138 {
139 
140 	sx_assert(&proctree_lock, SX_XLOCKED);
141 	if (p != td->td_proc)
142 		return (EPERM);
143 	if ((p->p_treeflag & P_TREE_REAPER) != 0)
144 		return (EBUSY);
145 	p->p_treeflag |= P_TREE_REAPER;
146 	/*
147 	 * We do not reattach existing children and the whole tree
148 	 * under them to us, since p->p_reaper already seen them.
149 	 */
150 	return (0);
151 }
152 
153 static int
154 reap_release(struct thread *td, struct proc *p, void *data __unused)
155 {
156 
157 	sx_assert(&proctree_lock, SX_XLOCKED);
158 	if (p != td->td_proc)
159 		return (EPERM);
160 	if (p == initproc)
161 		return (EINVAL);
162 	if ((p->p_treeflag & P_TREE_REAPER) == 0)
163 		return (EINVAL);
164 	reaper_abandon_children(p, false);
165 	return (0);
166 }
167 
168 static int
169 reap_status(struct thread *td, struct proc *p, void *data)
170 {
171 	struct proc *reap, *p2, *first_p;
172 	struct procctl_reaper_status *rs;
173 
174 	rs = data;
175 	sx_assert(&proctree_lock, SX_LOCKED);
176 	if ((p->p_treeflag & P_TREE_REAPER) == 0) {
177 		reap = p->p_reaper;
178 	} else {
179 		reap = p;
180 		rs->rs_flags |= REAPER_STATUS_OWNED;
181 	}
182 	if (reap == initproc)
183 		rs->rs_flags |= REAPER_STATUS_REALINIT;
184 	rs->rs_reaper = reap->p_pid;
185 	rs->rs_descendants = 0;
186 	rs->rs_children = 0;
187 	if (!LIST_EMPTY(&reap->p_reaplist)) {
188 		first_p = LIST_FIRST(&reap->p_children);
189 		if (first_p == NULL)
190 			first_p = LIST_FIRST(&reap->p_reaplist);
191 		rs->rs_pid = first_p->p_pid;
192 		LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
193 			if (proc_realparent(p2) == reap)
194 				rs->rs_children++;
195 			rs->rs_descendants++;
196 		}
197 	} else {
198 		rs->rs_pid = -1;
199 	}
200 	return (0);
201 }
202 
203 static int
204 reap_getpids(struct thread *td, struct proc *p, void *data)
205 {
206 	struct proc *reap, *p2;
207 	struct procctl_reaper_pidinfo *pi, *pip;
208 	struct procctl_reaper_pids *rp;
209 	u_int i, n;
210 	int error;
211 
212 	rp = data;
213 	sx_assert(&proctree_lock, SX_LOCKED);
214 	PROC_UNLOCK(p);
215 	reap = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
216 	n = i = 0;
217 	error = 0;
218 	LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling)
219 		n++;
220 	sx_unlock(&proctree_lock);
221 	if (rp->rp_count < n)
222 		n = rp->rp_count;
223 	pi = malloc(n * sizeof(*pi), M_TEMP, M_WAITOK);
224 	sx_slock(&proctree_lock);
225 	LIST_FOREACH(p2, &reap->p_reaplist, p_reapsibling) {
226 		if (i == n)
227 			break;
228 		pip = &pi[i];
229 		bzero(pip, sizeof(*pip));
230 		pip->pi_pid = p2->p_pid;
231 		pip->pi_subtree = p2->p_reapsubtree;
232 		pip->pi_flags = REAPER_PIDINFO_VALID;
233 		if (proc_realparent(p2) == reap)
234 			pip->pi_flags |= REAPER_PIDINFO_CHILD;
235 		if ((p2->p_treeflag & P_TREE_REAPER) != 0)
236 			pip->pi_flags |= REAPER_PIDINFO_REAPER;
237 		if ((p2->p_flag & P_STOPPED) != 0)
238 			pip->pi_flags |= REAPER_PIDINFO_STOPPED;
239 		if (p2->p_state == PRS_ZOMBIE)
240 			pip->pi_flags |= REAPER_PIDINFO_ZOMBIE;
241 		else if ((p2->p_flag & P_WEXIT) != 0)
242 			pip->pi_flags |= REAPER_PIDINFO_EXITING;
243 		i++;
244 	}
245 	sx_sunlock(&proctree_lock);
246 	error = copyout(pi, rp->rp_pids, i * sizeof(*pi));
247 	free(pi, M_TEMP);
248 	sx_slock(&proctree_lock);
249 	PROC_LOCK(p);
250 	return (error);
251 }
252 
253 struct reap_kill_proc_work {
254 	struct ucred *cr;
255 	struct proc *target;
256 	ksiginfo_t *ksi;
257 	struct procctl_reaper_kill *rk;
258 	int *error;
259 	struct task t;
260 };
261 
262 static void
263 reap_kill_proc_locked(struct reap_kill_proc_work *w)
264 {
265 	int error1;
266 	bool need_stop;
267 
268 	PROC_LOCK_ASSERT(w->target, MA_OWNED);
269 	PROC_ASSERT_HELD(w->target);
270 
271 	error1 = cr_cansignal(w->cr, w->target, w->rk->rk_sig);
272 	if (error1 != 0) {
273 		if (*w->error == ESRCH) {
274 			w->rk->rk_fpid = w->target->p_pid;
275 			*w->error = error1;
276 		}
277 		return;
278 	}
279 
280 	/*
281 	 * The need_stop indicates if the target process needs to be
282 	 * suspended before being signalled.  This is needed when we
283 	 * guarantee that all processes in subtree are signalled,
284 	 * avoiding the race with some process not yet fully linked
285 	 * into all structures during fork, ignored by iterator, and
286 	 * then escaping signalling.
287 	 *
288 	 * The thread cannot usefully stop itself anyway, and if other
289 	 * thread of the current process forks while the current
290 	 * thread signals the whole subtree, it is an application
291 	 * race.
292 	 */
293 	if ((w->target->p_flag & (P_KPROC | P_SYSTEM | P_STOPPED)) == 0)
294 		need_stop = thread_single(w->target, SINGLE_ALLPROC) == 0;
295 	else
296 		need_stop = false;
297 
298 	(void)pksignal(w->target, w->rk->rk_sig, w->ksi);
299 	w->rk->rk_killed++;
300 	*w->error = error1;
301 
302 	if (need_stop)
303 		thread_single_end(w->target, SINGLE_ALLPROC);
304 }
305 
306 static void
307 reap_kill_proc_work(void *arg, int pending __unused)
308 {
309 	struct reap_kill_proc_work *w;
310 
311 	w = arg;
312 	PROC_LOCK(w->target);
313 	if ((w->target->p_flag2 & P2_WEXIT) == 0)
314 		reap_kill_proc_locked(w);
315 	PROC_UNLOCK(w->target);
316 
317 	sx_xlock(&proctree_lock);
318 	w->target = NULL;
319 	wakeup(&w->target);
320 	sx_xunlock(&proctree_lock);
321 }
322 
323 struct reap_kill_tracker {
324 	struct proc *parent;
325 	TAILQ_ENTRY(reap_kill_tracker) link;
326 };
327 
328 TAILQ_HEAD(reap_kill_tracker_head, reap_kill_tracker);
329 
330 static void
331 reap_kill_sched(struct reap_kill_tracker_head *tracker, struct proc *p2)
332 {
333 	struct reap_kill_tracker *t;
334 
335 	PROC_LOCK(p2);
336 	if ((p2->p_flag2 & P2_WEXIT) != 0) {
337 		PROC_UNLOCK(p2);
338 		return;
339 	}
340 	_PHOLD(p2);
341 	PROC_UNLOCK(p2);
342 	t = malloc(sizeof(struct reap_kill_tracker), M_TEMP, M_WAITOK);
343 	t->parent = p2;
344 	TAILQ_INSERT_TAIL(tracker, t, link);
345 }
346 
347 static void
348 reap_kill_sched_free(struct reap_kill_tracker *t)
349 {
350 	PRELE(t->parent);
351 	free(t, M_TEMP);
352 }
353 
354 static void
355 reap_kill_children(struct thread *td, struct proc *reaper,
356     struct procctl_reaper_kill *rk, ksiginfo_t *ksi, int *error)
357 {
358 	struct proc *p2;
359 	int error1;
360 
361 	LIST_FOREACH(p2, &reaper->p_children, p_sibling) {
362 		PROC_LOCK(p2);
363 		if ((p2->p_flag2 & P2_WEXIT) == 0) {
364 			error1 = p_cansignal(td, p2, rk->rk_sig);
365 			if (error1 != 0) {
366 				if (*error == ESRCH) {
367 					rk->rk_fpid = p2->p_pid;
368 					*error = error1;
369 				}
370 
371 				/*
372 				 * Do not end the loop on error,
373 				 * signal everything we can.
374 				 */
375 			} else {
376 				(void)pksignal(p2, rk->rk_sig, ksi);
377 				rk->rk_killed++;
378 			}
379 		}
380 		PROC_UNLOCK(p2);
381 	}
382 }
383 
384 static bool
385 reap_kill_subtree_once(struct thread *td, struct proc *p, struct proc *reaper,
386     struct unrhdr *pids, struct reap_kill_proc_work *w)
387 {
388 	struct reap_kill_tracker_head tracker;
389 	struct reap_kill_tracker *t;
390 	struct proc *p2;
391 	int r, xlocked;
392 	bool res, st;
393 
394 	res = false;
395 	TAILQ_INIT(&tracker);
396 	reap_kill_sched(&tracker, reaper);
397 	while ((t = TAILQ_FIRST(&tracker)) != NULL) {
398 		TAILQ_REMOVE(&tracker, t, link);
399 
400 		/*
401 		 * Since reap_kill_proc() drops proctree_lock sx, it
402 		 * is possible that the tracked reaper is no longer.
403 		 * In this case the subtree is reparented to the new
404 		 * reaper, which should handle it.
405 		 */
406 		if ((t->parent->p_treeflag & P_TREE_REAPER) == 0) {
407 			reap_kill_sched_free(t);
408 			res = true;
409 			continue;
410 		}
411 
412 		LIST_FOREACH(p2, &t->parent->p_reaplist, p_reapsibling) {
413 			if (t->parent == reaper &&
414 			    (w->rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
415 			    p2->p_reapsubtree != w->rk->rk_subtree)
416 				continue;
417 			if ((p2->p_treeflag & P_TREE_REAPER) != 0)
418 				reap_kill_sched(&tracker, p2);
419 
420 			/*
421 			 * Handle possible pid reuse.  If we recorded
422 			 * p2 as killed but its p_flag2 does not
423 			 * confirm it, that means that the process
424 			 * terminated and its id was reused by other
425 			 * process in the reaper subtree.
426 			 *
427 			 * Unlocked read of p2->p_flag2 is fine, it is
428 			 * our thread that set the tested flag.
429 			 */
430 			if (alloc_unr_specific(pids, p2->p_pid) != p2->p_pid &&
431 			    (atomic_load_int(&p2->p_flag2) &
432 			    (P2_REAPKILLED | P2_WEXIT)) != 0)
433 				continue;
434 
435 			if (p2 == td->td_proc) {
436 				if ((p2->p_flag & P_HADTHREADS) != 0 &&
437 				    (p2->p_flag2 & P2_WEXIT) == 0) {
438 					xlocked = sx_xlocked(&proctree_lock);
439 					sx_unlock(&proctree_lock);
440 					st = true;
441 				} else {
442 					st = false;
443 				}
444 				PROC_LOCK(p2);
445 				/*
446 				 * sapblk ensures that only one thread
447 				 * in the system sets this flag.
448 				 */
449 				p2->p_flag2 |= P2_REAPKILLED;
450 				if (st)
451 					r = thread_single(p2, SINGLE_NO_EXIT);
452 				(void)pksignal(p2, w->rk->rk_sig, w->ksi);
453 				w->rk->rk_killed++;
454 				if (st && r == 0)
455 					thread_single_end(p2, SINGLE_NO_EXIT);
456 				PROC_UNLOCK(p2);
457 				if (st) {
458 					if (xlocked)
459 						sx_xlock(&proctree_lock);
460 					else
461 						sx_slock(&proctree_lock);
462 				}
463 			} else {
464 				PROC_LOCK(p2);
465 				if ((p2->p_flag2 & P2_WEXIT) == 0) {
466 					_PHOLD(p2);
467 					p2->p_flag2 |= P2_REAPKILLED;
468 					PROC_UNLOCK(p2);
469 					w->target = p2;
470 					taskqueue_enqueue(taskqueue_thread,
471 					    &w->t);
472 					while (w->target != NULL) {
473 						sx_sleep(&w->target,
474 						    &proctree_lock, PWAIT,
475 						    "reapst", 0);
476 					}
477 					PROC_LOCK(p2);
478 					_PRELE(p2);
479 				}
480 				PROC_UNLOCK(p2);
481 			}
482 			res = true;
483 		}
484 		reap_kill_sched_free(t);
485 	}
486 	return (res);
487 }
488 
489 static void
490 reap_kill_subtree(struct thread *td, struct proc *p, struct proc *reaper,
491     struct reap_kill_proc_work *w)
492 {
493 	struct unrhdr pids;
494 	void *ihandle;
495 	struct proc *p2;
496 	int pid;
497 
498 	/*
499 	 * pids records processes which were already signalled, to
500 	 * avoid doubling signals to them if iteration needs to be
501 	 * repeated.
502 	 */
503 	init_unrhdr(&pids, 1, PID_MAX, UNR_NO_MTX);
504 	PROC_LOCK(td->td_proc);
505 	if ((td->td_proc->p_flag2 & P2_WEXIT) != 0) {
506 		PROC_UNLOCK(td->td_proc);
507 		goto out;
508 	}
509 	PROC_UNLOCK(td->td_proc);
510 	while (reap_kill_subtree_once(td, p, reaper, &pids, w))
511 	       ;
512 
513 	ihandle = create_iter_unr(&pids);
514 	while ((pid = next_iter_unr(ihandle)) != -1) {
515 		p2 = pfind(pid);
516 		if (p2 != NULL) {
517 			p2->p_flag2 &= ~P2_REAPKILLED;
518 			PROC_UNLOCK(p2);
519 		}
520 	}
521 	free_iter_unr(ihandle);
522 
523 out:
524 	clean_unrhdr(&pids);
525 	clear_unrhdr(&pids);
526 }
527 
528 static bool
529 reap_kill_sapblk(struct thread *td __unused, void *data)
530 {
531 	struct procctl_reaper_kill *rk;
532 
533 	rk = data;
534 	return ((rk->rk_flags & REAPER_KILL_CHILDREN) == 0);
535 }
536 
537 static int
538 reap_kill(struct thread *td, struct proc *p, void *data)
539 {
540 	struct reap_kill_proc_work w;
541 	struct proc *reaper;
542 	ksiginfo_t ksi;
543 	struct procctl_reaper_kill *rk;
544 	int error;
545 
546 	rk = data;
547 	sx_assert(&proctree_lock, SX_LOCKED);
548 	if (CAP_TRACING(td))
549 		ktrcapfail(CAPFAIL_SIGNAL, &rk->rk_sig);
550 	if (IN_CAPABILITY_MODE(td))
551 		return (ECAPMODE);
552 	if (rk->rk_sig <= 0 || rk->rk_sig > _SIG_MAXSIG ||
553 	    (rk->rk_flags & ~(REAPER_KILL_CHILDREN |
554 	    REAPER_KILL_SUBTREE)) != 0 || (rk->rk_flags &
555 	    (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE)) ==
556 	    (REAPER_KILL_CHILDREN | REAPER_KILL_SUBTREE))
557 		return (EINVAL);
558 	PROC_UNLOCK(p);
559 	reaper = (p->p_treeflag & P_TREE_REAPER) == 0 ? p->p_reaper : p;
560 	ksiginfo_init(&ksi);
561 	ksi.ksi_signo = rk->rk_sig;
562 	ksi.ksi_code = SI_USER;
563 	ksi.ksi_pid = td->td_proc->p_pid;
564 	ksi.ksi_uid = td->td_ucred->cr_ruid;
565 	error = ESRCH;
566 	rk->rk_killed = 0;
567 	rk->rk_fpid = -1;
568 	if ((rk->rk_flags & REAPER_KILL_CHILDREN) != 0) {
569 		reap_kill_children(td, reaper, rk, &ksi, &error);
570 	} else {
571 		w.cr = crhold(td->td_ucred);
572 		w.ksi = &ksi;
573 		w.rk = rk;
574 		w.error = &error;
575 		TASK_INIT(&w.t, 0, reap_kill_proc_work, &w);
576 		reap_kill_subtree(td, p, reaper, &w);
577 		crfree(w.cr);
578 	}
579 	PROC_LOCK(p);
580 	return (error);
581 }
582 
583 static int
584 trace_ctl(struct thread *td, struct proc *p, void *data)
585 {
586 	int state;
587 
588 	PROC_LOCK_ASSERT(p, MA_OWNED);
589 	state = *(int *)data;
590 
591 	/*
592 	 * Ktrace changes p_traceflag from or to zero under the
593 	 * process lock, so the test does not need to acquire ktrace
594 	 * mutex.
595 	 */
596 	if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0)
597 		return (EBUSY);
598 
599 	switch (state) {
600 	case PROC_TRACE_CTL_ENABLE:
601 		if (td->td_proc != p)
602 			return (EPERM);
603 		p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC);
604 		break;
605 	case PROC_TRACE_CTL_DISABLE_EXEC:
606 		p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE;
607 		break;
608 	case PROC_TRACE_CTL_DISABLE:
609 		if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) {
610 			KASSERT((p->p_flag2 & P2_NOTRACE) != 0,
611 			    ("dandling P2_NOTRACE_EXEC"));
612 			if (td->td_proc != p)
613 				return (EPERM);
614 			p->p_flag2 &= ~P2_NOTRACE_EXEC;
615 		} else {
616 			p->p_flag2 |= P2_NOTRACE;
617 		}
618 		break;
619 	default:
620 		return (EINVAL);
621 	}
622 	return (0);
623 }
624 
625 static int
626 trace_status(struct thread *td, struct proc *p, void *data)
627 {
628 	int *status;
629 
630 	status = data;
631 	if ((p->p_flag2 & P2_NOTRACE) != 0) {
632 		KASSERT((p->p_flag & P_TRACED) == 0,
633 		    ("%d traced but tracing disabled", p->p_pid));
634 		*status = -1;
635 	} else if ((p->p_flag & P_TRACED) != 0) {
636 		*status = p->p_pptr->p_pid;
637 	} else {
638 		*status = 0;
639 	}
640 	return (0);
641 }
642 
643 static int
644 trapcap_ctl(struct thread *td, struct proc *p, void *data)
645 {
646 	int state;
647 
648 	PROC_LOCK_ASSERT(p, MA_OWNED);
649 	state = *(int *)data;
650 
651 	switch (state) {
652 	case PROC_TRAPCAP_CTL_ENABLE:
653 		p->p_flag2 |= P2_TRAPCAP;
654 		break;
655 	case PROC_TRAPCAP_CTL_DISABLE:
656 		p->p_flag2 &= ~P2_TRAPCAP;
657 		break;
658 	default:
659 		return (EINVAL);
660 	}
661 	return (0);
662 }
663 
664 static int
665 trapcap_status(struct thread *td, struct proc *p, void *data)
666 {
667 	int *status;
668 
669 	status = data;
670 	*status = (p->p_flag2 & P2_TRAPCAP) != 0 ? PROC_TRAPCAP_CTL_ENABLE :
671 	    PROC_TRAPCAP_CTL_DISABLE;
672 	return (0);
673 }
674 
675 static int
676 no_new_privs_ctl(struct thread *td, struct proc *p, void *data)
677 {
678 	int state;
679 
680 	PROC_LOCK_ASSERT(p, MA_OWNED);
681 	state = *(int *)data;
682 
683 	if (state != PROC_NO_NEW_PRIVS_ENABLE)
684 		return (EINVAL);
685 	p->p_flag2 |= P2_NO_NEW_PRIVS;
686 	return (0);
687 }
688 
689 static int
690 no_new_privs_status(struct thread *td, struct proc *p, void *data)
691 {
692 
693 	*(int *)data = (p->p_flag2 & P2_NO_NEW_PRIVS) != 0 ?
694 	    PROC_NO_NEW_PRIVS_ENABLE : PROC_NO_NEW_PRIVS_DISABLE;
695 	return (0);
696 }
697 
698 static int
699 protmax_ctl(struct thread *td, struct proc *p, void *data)
700 {
701 	int state;
702 
703 	PROC_LOCK_ASSERT(p, MA_OWNED);
704 	state = *(int *)data;
705 
706 	switch (state) {
707 	case PROC_PROTMAX_FORCE_ENABLE:
708 		p->p_flag2 &= ~P2_PROTMAX_DISABLE;
709 		p->p_flag2 |= P2_PROTMAX_ENABLE;
710 		break;
711 	case PROC_PROTMAX_FORCE_DISABLE:
712 		p->p_flag2 |= P2_PROTMAX_DISABLE;
713 		p->p_flag2 &= ~P2_PROTMAX_ENABLE;
714 		break;
715 	case PROC_PROTMAX_NOFORCE:
716 		p->p_flag2 &= ~(P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE);
717 		break;
718 	default:
719 		return (EINVAL);
720 	}
721 	return (0);
722 }
723 
724 static int
725 protmax_status(struct thread *td, struct proc *p, void *data)
726 {
727 	int d;
728 
729 	switch (p->p_flag2 & (P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE)) {
730 	case 0:
731 		d = PROC_PROTMAX_NOFORCE;
732 		break;
733 	case P2_PROTMAX_ENABLE:
734 		d = PROC_PROTMAX_FORCE_ENABLE;
735 		break;
736 	case P2_PROTMAX_DISABLE:
737 		d = PROC_PROTMAX_FORCE_DISABLE;
738 		break;
739 	}
740 	if (kern_mmap_maxprot(p, PROT_READ) == PROT_READ)
741 		d |= PROC_PROTMAX_ACTIVE;
742 	*(int *)data = d;
743 	return (0);
744 }
745 
746 static int
747 aslr_ctl(struct thread *td, struct proc *p, void *data)
748 {
749 	int state;
750 
751 	PROC_LOCK_ASSERT(p, MA_OWNED);
752 	state = *(int *)data;
753 
754 	switch (state) {
755 	case PROC_ASLR_FORCE_ENABLE:
756 		p->p_flag2 &= ~P2_ASLR_DISABLE;
757 		p->p_flag2 |= P2_ASLR_ENABLE;
758 		break;
759 	case PROC_ASLR_FORCE_DISABLE:
760 		p->p_flag2 |= P2_ASLR_DISABLE;
761 		p->p_flag2 &= ~P2_ASLR_ENABLE;
762 		break;
763 	case PROC_ASLR_NOFORCE:
764 		p->p_flag2 &= ~(P2_ASLR_ENABLE | P2_ASLR_DISABLE);
765 		break;
766 	default:
767 		return (EINVAL);
768 	}
769 	return (0);
770 }
771 
772 static int
773 aslr_status(struct thread *td, struct proc *p, void *data)
774 {
775 	struct vmspace *vm;
776 	int d;
777 
778 	switch (p->p_flag2 & (P2_ASLR_ENABLE | P2_ASLR_DISABLE)) {
779 	case 0:
780 		d = PROC_ASLR_NOFORCE;
781 		break;
782 	case P2_ASLR_ENABLE:
783 		d = PROC_ASLR_FORCE_ENABLE;
784 		break;
785 	case P2_ASLR_DISABLE:
786 		d = PROC_ASLR_FORCE_DISABLE;
787 		break;
788 	}
789 	if ((p->p_flag & P_WEXIT) == 0) {
790 		_PHOLD(p);
791 		PROC_UNLOCK(p);
792 		vm = vmspace_acquire_ref(p);
793 		if (vm != NULL) {
794 			if ((vm->vm_map.flags & MAP_ASLR) != 0)
795 				d |= PROC_ASLR_ACTIVE;
796 			vmspace_free(vm);
797 		}
798 		PROC_LOCK(p);
799 		_PRELE(p);
800 	}
801 	*(int *)data = d;
802 	return (0);
803 }
804 
805 static int
806 stackgap_ctl(struct thread *td, struct proc *p, void *data)
807 {
808 	int state;
809 
810 	PROC_LOCK_ASSERT(p, MA_OWNED);
811 	state = *(int *)data;
812 
813 	if ((state & ~(PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE |
814 	    PROC_STACKGAP_ENABLE_EXEC | PROC_STACKGAP_DISABLE_EXEC)) != 0)
815 		return (EINVAL);
816 	switch (state & (PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE)) {
817 	case PROC_STACKGAP_ENABLE:
818 		if ((p->p_flag2 & P2_STKGAP_DISABLE) != 0)
819 			return (EINVAL);
820 		break;
821 	case PROC_STACKGAP_DISABLE:
822 		p->p_flag2 |= P2_STKGAP_DISABLE;
823 		break;
824 	case 0:
825 		break;
826 	default:
827 		return (EINVAL);
828 	}
829 	switch (state & (PROC_STACKGAP_ENABLE_EXEC |
830 	    PROC_STACKGAP_DISABLE_EXEC)) {
831 	case PROC_STACKGAP_ENABLE_EXEC:
832 		p->p_flag2 &= ~P2_STKGAP_DISABLE_EXEC;
833 		break;
834 	case PROC_STACKGAP_DISABLE_EXEC:
835 		p->p_flag2 |= P2_STKGAP_DISABLE_EXEC;
836 		break;
837 	case 0:
838 		break;
839 	default:
840 		return (EINVAL);
841 	}
842 	return (0);
843 }
844 
845 static int
846 stackgap_status(struct thread *td, struct proc *p, void *data)
847 {
848 	int d;
849 
850 	PROC_LOCK_ASSERT(p, MA_OWNED);
851 
852 	d = (p->p_flag2 & P2_STKGAP_DISABLE) != 0 ? PROC_STACKGAP_DISABLE :
853 	    PROC_STACKGAP_ENABLE;
854 	d |= (p->p_flag2 & P2_STKGAP_DISABLE_EXEC) != 0 ?
855 	    PROC_STACKGAP_DISABLE_EXEC : PROC_STACKGAP_ENABLE_EXEC;
856 	*(int *)data = d;
857 	return (0);
858 }
859 
860 static int
861 wxmap_ctl(struct thread *td, struct proc *p, void *data)
862 {
863 	struct vmspace *vm;
864 	vm_map_t map;
865 	int state;
866 
867 	PROC_LOCK_ASSERT(p, MA_OWNED);
868 	if ((p->p_flag & P_WEXIT) != 0)
869 		return (ESRCH);
870 	state = *(int *)data;
871 
872 	switch (state) {
873 	case PROC_WX_MAPPINGS_PERMIT:
874 		p->p_flag2 |= P2_WXORX_DISABLE;
875 		_PHOLD(p);
876 		PROC_UNLOCK(p);
877 		vm = vmspace_acquire_ref(p);
878 		if (vm != NULL) {
879 			map = &vm->vm_map;
880 			vm_map_lock(map);
881 			map->flags &= ~MAP_WXORX;
882 			vm_map_unlock(map);
883 			vmspace_free(vm);
884 		}
885 		PROC_LOCK(p);
886 		_PRELE(p);
887 		break;
888 	case PROC_WX_MAPPINGS_DISALLOW_EXEC:
889 		p->p_flag2 |= P2_WXORX_ENABLE_EXEC;
890 		break;
891 	default:
892 		return (EINVAL);
893 	}
894 
895 	return (0);
896 }
897 
898 static int
899 wxmap_status(struct thread *td, struct proc *p, void *data)
900 {
901 	struct vmspace *vm;
902 	int d;
903 
904 	PROC_LOCK_ASSERT(p, MA_OWNED);
905 	if ((p->p_flag & P_WEXIT) != 0)
906 		return (ESRCH);
907 
908 	d = 0;
909 	if ((p->p_flag2 & P2_WXORX_DISABLE) != 0)
910 		d |= PROC_WX_MAPPINGS_PERMIT;
911 	if ((p->p_flag2 & P2_WXORX_ENABLE_EXEC) != 0)
912 		d |= PROC_WX_MAPPINGS_DISALLOW_EXEC;
913 	_PHOLD(p);
914 	PROC_UNLOCK(p);
915 	vm = vmspace_acquire_ref(p);
916 	if (vm != NULL) {
917 		if ((vm->vm_map.flags & MAP_WXORX) != 0)
918 			d |= PROC_WXORX_ENFORCE;
919 		vmspace_free(vm);
920 	}
921 	PROC_LOCK(p);
922 	_PRELE(p);
923 	*(int *)data = d;
924 	return (0);
925 }
926 
927 static int
928 pdeathsig_ctl(struct thread *td, struct proc *p, void *data)
929 {
930 	int signum;
931 
932 	signum = *(int *)data;
933 	if (p != td->td_proc || (signum != 0 && !_SIG_VALID(signum)))
934 		return (EINVAL);
935 	p->p_pdeathsig = signum;
936 	return (0);
937 }
938 
939 static int
940 pdeathsig_status(struct thread *td, struct proc *p, void *data)
941 {
942 	if (p != td->td_proc)
943 		return (EINVAL);
944 	*(int *)data = p->p_pdeathsig;
945 	return (0);
946 }
947 
948 enum {
949 	PCTL_SLOCKED,
950 	PCTL_XLOCKED,
951 	PCTL_UNLOCKED,
952 };
953 
954 struct procctl_cmd_info {
955 	int lock_tree;
956 	bool one_proc : 1;
957 	bool esrch_is_einval : 1;
958 	bool copyout_on_error : 1;
959 	bool no_nonnull_data : 1;
960 	bool need_candebug : 1;
961 	int copyin_sz;
962 	int copyout_sz;
963 	int (*exec)(struct thread *, struct proc *, void *);
964 	bool (*sapblk)(struct thread *, void *);
965 };
966 static const struct procctl_cmd_info procctl_cmds_info[] = {
967 	[PROC_SPROTECT] =
968 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
969 	      .esrch_is_einval = false, .no_nonnull_data = false,
970 	      .need_candebug = false,
971 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
972 	      .exec = protect_set, .copyout_on_error = false, },
973 	[PROC_REAP_ACQUIRE] =
974 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
975 	      .esrch_is_einval = false, .no_nonnull_data = true,
976 	      .need_candebug = false,
977 	      .copyin_sz = 0, .copyout_sz = 0,
978 	      .exec = reap_acquire, .copyout_on_error = false, },
979 	[PROC_REAP_RELEASE] =
980 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
981 	      .esrch_is_einval = false, .no_nonnull_data = true,
982 	      .need_candebug = false,
983 	      .copyin_sz = 0, .copyout_sz = 0,
984 	      .exec = reap_release, .copyout_on_error = false, },
985 	[PROC_REAP_STATUS] =
986 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
987 	      .esrch_is_einval = false, .no_nonnull_data = false,
988 	      .need_candebug = false,
989 	      .copyin_sz = 0,
990 	      .copyout_sz = sizeof(struct procctl_reaper_status),
991 	      .exec = reap_status, .copyout_on_error = false, },
992 	[PROC_REAP_GETPIDS] =
993 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
994 	      .esrch_is_einval = false, .no_nonnull_data = false,
995 	      .need_candebug = false,
996 	      .copyin_sz = sizeof(struct procctl_reaper_pids),
997 	      .copyout_sz = 0,
998 	      .exec = reap_getpids, .copyout_on_error = false, },
999 	[PROC_REAP_KILL] =
1000 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1001 	      .esrch_is_einval = false, .no_nonnull_data = false,
1002 	      .need_candebug = false,
1003 	      .copyin_sz = sizeof(struct procctl_reaper_kill),
1004 	      .copyout_sz = sizeof(struct procctl_reaper_kill),
1005 	      .exec = reap_kill, .copyout_on_error = true,
1006 	      .sapblk = reap_kill_sapblk, },
1007 	[PROC_TRACE_CTL] =
1008 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1009 	      .esrch_is_einval = false, .no_nonnull_data = false,
1010 	      .need_candebug = true,
1011 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1012 	      .exec = trace_ctl, .copyout_on_error = false, },
1013 	[PROC_TRACE_STATUS] =
1014 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1015 	      .esrch_is_einval = false, .no_nonnull_data = false,
1016 	      .need_candebug = false,
1017 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1018 	      .exec = trace_status, .copyout_on_error = false, },
1019 	[PROC_TRAPCAP_CTL] =
1020 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1021 	      .esrch_is_einval = false, .no_nonnull_data = false,
1022 	      .need_candebug = true,
1023 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1024 	      .exec = trapcap_ctl, .copyout_on_error = false, },
1025 	[PROC_TRAPCAP_STATUS] =
1026 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1027 	      .esrch_is_einval = false, .no_nonnull_data = false,
1028 	      .need_candebug = false,
1029 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1030 	      .exec = trapcap_status, .copyout_on_error = false, },
1031 	[PROC_PDEATHSIG_CTL] =
1032 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1033 	      .esrch_is_einval = true, .no_nonnull_data = false,
1034 	      .need_candebug = false,
1035 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1036 	      .exec = pdeathsig_ctl, .copyout_on_error = false, },
1037 	[PROC_PDEATHSIG_STATUS] =
1038 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1039 	      .esrch_is_einval = true, .no_nonnull_data = false,
1040 	      .need_candebug = false,
1041 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1042 	      .exec = pdeathsig_status, .copyout_on_error = false, },
1043 	[PROC_ASLR_CTL] =
1044 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1045 	      .esrch_is_einval = false, .no_nonnull_data = false,
1046 	      .need_candebug = true,
1047 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1048 	      .exec = aslr_ctl, .copyout_on_error = false, },
1049 	[PROC_ASLR_STATUS] =
1050 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1051 	      .esrch_is_einval = false, .no_nonnull_data = false,
1052 	      .need_candebug = false,
1053 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1054 	      .exec = aslr_status, .copyout_on_error = false, },
1055 	[PROC_PROTMAX_CTL] =
1056 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1057 	      .esrch_is_einval = false, .no_nonnull_data = false,
1058 	      .need_candebug = true,
1059 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1060 	      .exec = protmax_ctl, .copyout_on_error = false, },
1061 	[PROC_PROTMAX_STATUS] =
1062 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1063 	      .esrch_is_einval = false, .no_nonnull_data = false,
1064 	      .need_candebug = false,
1065 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1066 	      .exec = protmax_status, .copyout_on_error = false, },
1067 	[PROC_STACKGAP_CTL] =
1068 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1069 	      .esrch_is_einval = false, .no_nonnull_data = false,
1070 	      .need_candebug = true,
1071 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1072 	      .exec = stackgap_ctl, .copyout_on_error = false, },
1073 	[PROC_STACKGAP_STATUS] =
1074 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1075 	      .esrch_is_einval = false, .no_nonnull_data = false,
1076 	      .need_candebug = false,
1077 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1078 	      .exec = stackgap_status, .copyout_on_error = false, },
1079 	[PROC_NO_NEW_PRIVS_CTL] =
1080 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1081 	      .esrch_is_einval = false, .no_nonnull_data = false,
1082 	      .need_candebug = true,
1083 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1084 	      .exec = no_new_privs_ctl, .copyout_on_error = false, },
1085 	[PROC_NO_NEW_PRIVS_STATUS] =
1086 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1087 	      .esrch_is_einval = false, .no_nonnull_data = false,
1088 	      .need_candebug = false,
1089 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1090 	      .exec = no_new_privs_status, .copyout_on_error = false, },
1091 	[PROC_WXMAP_CTL] =
1092 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1093 	      .esrch_is_einval = false, .no_nonnull_data = false,
1094 	      .need_candebug = true,
1095 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1096 	      .exec = wxmap_ctl, .copyout_on_error = false, },
1097 	[PROC_WXMAP_STATUS] =
1098 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1099 	      .esrch_is_einval = false, .no_nonnull_data = false,
1100 	      .need_candebug = false,
1101 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1102 	      .exec = wxmap_status, .copyout_on_error = false, },
1103 };
1104 
1105 int
1106 sys_procctl(struct thread *td, struct procctl_args *uap)
1107 {
1108 	union {
1109 		struct procctl_reaper_status rs;
1110 		struct procctl_reaper_pids rp;
1111 		struct procctl_reaper_kill rk;
1112 		int flags;
1113 	} x;
1114 	const struct procctl_cmd_info *cmd_info;
1115 	int error, error1;
1116 
1117 	if (uap->com >= PROC_PROCCTL_MD_MIN)
1118 		return (cpu_procctl(td, uap->idtype, uap->id,
1119 		    uap->com, uap->data));
1120 	if (uap->com <= 0 || uap->com >= nitems(procctl_cmds_info))
1121 		return (EINVAL);
1122 	cmd_info = &procctl_cmds_info[uap->com];
1123 	bzero(&x, sizeof(x));
1124 
1125 	if (cmd_info->copyin_sz > 0) {
1126 		error = copyin(uap->data, &x, cmd_info->copyin_sz);
1127 		if (error != 0)
1128 			return (error);
1129 	} else if (cmd_info->no_nonnull_data && uap->data != NULL) {
1130 		return (EINVAL);
1131 	}
1132 
1133 	error = kern_procctl(td, uap->idtype, uap->id, uap->com, &x);
1134 
1135 	if (cmd_info->copyout_sz > 0 && (error == 0 ||
1136 	    cmd_info->copyout_on_error)) {
1137 		error1 = copyout(&x, uap->data, cmd_info->copyout_sz);
1138 		if (error == 0)
1139 			error = error1;
1140 	}
1141 	return (error);
1142 }
1143 
1144 static int
1145 kern_procctl_single(struct thread *td, struct proc *p, int com, void *data)
1146 {
1147 
1148 	PROC_LOCK_ASSERT(p, MA_OWNED);
1149 	return (procctl_cmds_info[com].exec(td, p, data));
1150 }
1151 
1152 int
1153 kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data)
1154 {
1155 	struct pgrp *pg;
1156 	struct proc *p;
1157 	const struct procctl_cmd_info *cmd_info;
1158 	int error, first_error, ok;
1159 	bool sapblk;
1160 
1161 	MPASS(com > 0 && com < nitems(procctl_cmds_info));
1162 	cmd_info = &procctl_cmds_info[com];
1163 	if (idtype != P_PID && cmd_info->one_proc)
1164 		return (EINVAL);
1165 
1166 	sapblk = false;
1167 	if (cmd_info->sapblk != NULL) {
1168 		sapblk = cmd_info->sapblk(td, data);
1169 		if (sapblk && !stop_all_proc_block())
1170 			return (ERESTART);
1171 	}
1172 
1173 	switch (cmd_info->lock_tree) {
1174 	case PCTL_XLOCKED:
1175 		sx_xlock(&proctree_lock);
1176 		break;
1177 	case PCTL_SLOCKED:
1178 		sx_slock(&proctree_lock);
1179 		break;
1180 	default:
1181 		break;
1182 	}
1183 
1184 	switch (idtype) {
1185 	case P_PID:
1186 		if (id == 0) {
1187 			p = td->td_proc;
1188 			error = 0;
1189 			PROC_LOCK(p);
1190 		} else {
1191 			p = pfind(id);
1192 			if (p == NULL) {
1193 				error = cmd_info->esrch_is_einval ?
1194 				    EINVAL : ESRCH;
1195 				break;
1196 			}
1197 			error = cmd_info->need_candebug ? p_candebug(td, p) :
1198 			    p_cansee(td, p);
1199 		}
1200 		if (error == 0)
1201 			error = kern_procctl_single(td, p, com, data);
1202 		PROC_UNLOCK(p);
1203 		break;
1204 	case P_PGID:
1205 		/*
1206 		 * Attempt to apply the operation to all members of the
1207 		 * group.  Ignore processes in the group that can't be
1208 		 * seen.  Ignore errors so long as at least one process is
1209 		 * able to complete the request successfully.
1210 		 */
1211 		pg = pgfind(id);
1212 		if (pg == NULL) {
1213 			error = ESRCH;
1214 			break;
1215 		}
1216 		PGRP_UNLOCK(pg);
1217 		ok = 0;
1218 		first_error = 0;
1219 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
1220 			PROC_LOCK(p);
1221 			if (p->p_state == PRS_NEW ||
1222 			    p->p_state == PRS_ZOMBIE ||
1223 			    (cmd_info->need_candebug ? p_candebug(td, p) :
1224 			    p_cansee(td, p)) != 0) {
1225 				PROC_UNLOCK(p);
1226 				continue;
1227 			}
1228 			error = kern_procctl_single(td, p, com, data);
1229 			PROC_UNLOCK(p);
1230 			if (error == 0)
1231 				ok = 1;
1232 			else if (first_error == 0)
1233 				first_error = error;
1234 		}
1235 		if (ok)
1236 			error = 0;
1237 		else if (first_error != 0)
1238 			error = first_error;
1239 		else
1240 			/*
1241 			 * Was not able to see any processes in the
1242 			 * process group.
1243 			 */
1244 			error = ESRCH;
1245 		break;
1246 	default:
1247 		error = EINVAL;
1248 		break;
1249 	}
1250 
1251 	switch (cmd_info->lock_tree) {
1252 	case PCTL_XLOCKED:
1253 		sx_xunlock(&proctree_lock);
1254 		break;
1255 	case PCTL_SLOCKED:
1256 		sx_sunlock(&proctree_lock);
1257 		break;
1258 	default:
1259 		break;
1260 	}
1261 	if (sapblk)
1262 		stop_all_proc_unblock();
1263 	return (error);
1264 }
1265