xref: /freebsd/sys/kern/kern_procctl.c (revision 6580f5c38dd5b01aeeaed16b370f1a12423437f0)
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_LITE(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_LITE(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 
577 		/*
578 		 * Prevent swapout, since w, ksi, and possibly rk, are
579 		 * allocated on the stack.  We sleep in
580 		 * reap_kill_subtree_once() waiting for task to
581 		 * complete single-threading.
582 		 */
583 		PHOLD(td->td_proc);
584 
585 		reap_kill_subtree(td, p, reaper, &w);
586 		PRELE(td->td_proc);
587 		crfree(w.cr);
588 	}
589 	PROC_LOCK(p);
590 	return (error);
591 }
592 
593 static int
594 trace_ctl(struct thread *td, struct proc *p, void *data)
595 {
596 	int state;
597 
598 	PROC_LOCK_ASSERT(p, MA_OWNED);
599 	state = *(int *)data;
600 
601 	/*
602 	 * Ktrace changes p_traceflag from or to zero under the
603 	 * process lock, so the test does not need to acquire ktrace
604 	 * mutex.
605 	 */
606 	if ((p->p_flag & P_TRACED) != 0 || p->p_traceflag != 0)
607 		return (EBUSY);
608 
609 	switch (state) {
610 	case PROC_TRACE_CTL_ENABLE:
611 		if (td->td_proc != p)
612 			return (EPERM);
613 		p->p_flag2 &= ~(P2_NOTRACE | P2_NOTRACE_EXEC);
614 		break;
615 	case PROC_TRACE_CTL_DISABLE_EXEC:
616 		p->p_flag2 |= P2_NOTRACE_EXEC | P2_NOTRACE;
617 		break;
618 	case PROC_TRACE_CTL_DISABLE:
619 		if ((p->p_flag2 & P2_NOTRACE_EXEC) != 0) {
620 			KASSERT((p->p_flag2 & P2_NOTRACE) != 0,
621 			    ("dandling P2_NOTRACE_EXEC"));
622 			if (td->td_proc != p)
623 				return (EPERM);
624 			p->p_flag2 &= ~P2_NOTRACE_EXEC;
625 		} else {
626 			p->p_flag2 |= P2_NOTRACE;
627 		}
628 		break;
629 	default:
630 		return (EINVAL);
631 	}
632 	return (0);
633 }
634 
635 static int
636 trace_status(struct thread *td, struct proc *p, void *data)
637 {
638 	int *status;
639 
640 	status = data;
641 	if ((p->p_flag2 & P2_NOTRACE) != 0) {
642 		KASSERT((p->p_flag & P_TRACED) == 0,
643 		    ("%d traced but tracing disabled", p->p_pid));
644 		*status = -1;
645 	} else if ((p->p_flag & P_TRACED) != 0) {
646 		*status = p->p_pptr->p_pid;
647 	} else {
648 		*status = 0;
649 	}
650 	return (0);
651 }
652 
653 static int
654 trapcap_ctl(struct thread *td, struct proc *p, void *data)
655 {
656 	int state;
657 
658 	PROC_LOCK_ASSERT(p, MA_OWNED);
659 	state = *(int *)data;
660 
661 	switch (state) {
662 	case PROC_TRAPCAP_CTL_ENABLE:
663 		p->p_flag2 |= P2_TRAPCAP;
664 		break;
665 	case PROC_TRAPCAP_CTL_DISABLE:
666 		p->p_flag2 &= ~P2_TRAPCAP;
667 		break;
668 	default:
669 		return (EINVAL);
670 	}
671 	return (0);
672 }
673 
674 static int
675 trapcap_status(struct thread *td, struct proc *p, void *data)
676 {
677 	int *status;
678 
679 	status = data;
680 	*status = (p->p_flag2 & P2_TRAPCAP) != 0 ? PROC_TRAPCAP_CTL_ENABLE :
681 	    PROC_TRAPCAP_CTL_DISABLE;
682 	return (0);
683 }
684 
685 static int
686 no_new_privs_ctl(struct thread *td, struct proc *p, void *data)
687 {
688 	int state;
689 
690 	PROC_LOCK_ASSERT(p, MA_OWNED);
691 	state = *(int *)data;
692 
693 	if (state != PROC_NO_NEW_PRIVS_ENABLE)
694 		return (EINVAL);
695 	p->p_flag2 |= P2_NO_NEW_PRIVS;
696 	return (0);
697 }
698 
699 static int
700 no_new_privs_status(struct thread *td, struct proc *p, void *data)
701 {
702 
703 	*(int *)data = (p->p_flag2 & P2_NO_NEW_PRIVS) != 0 ?
704 	    PROC_NO_NEW_PRIVS_ENABLE : PROC_NO_NEW_PRIVS_DISABLE;
705 	return (0);
706 }
707 
708 static int
709 protmax_ctl(struct thread *td, struct proc *p, void *data)
710 {
711 	int state;
712 
713 	PROC_LOCK_ASSERT(p, MA_OWNED);
714 	state = *(int *)data;
715 
716 	switch (state) {
717 	case PROC_PROTMAX_FORCE_ENABLE:
718 		p->p_flag2 &= ~P2_PROTMAX_DISABLE;
719 		p->p_flag2 |= P2_PROTMAX_ENABLE;
720 		break;
721 	case PROC_PROTMAX_FORCE_DISABLE:
722 		p->p_flag2 |= P2_PROTMAX_DISABLE;
723 		p->p_flag2 &= ~P2_PROTMAX_ENABLE;
724 		break;
725 	case PROC_PROTMAX_NOFORCE:
726 		p->p_flag2 &= ~(P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE);
727 		break;
728 	default:
729 		return (EINVAL);
730 	}
731 	return (0);
732 }
733 
734 static int
735 protmax_status(struct thread *td, struct proc *p, void *data)
736 {
737 	int d;
738 
739 	switch (p->p_flag2 & (P2_PROTMAX_ENABLE | P2_PROTMAX_DISABLE)) {
740 	case 0:
741 		d = PROC_PROTMAX_NOFORCE;
742 		break;
743 	case P2_PROTMAX_ENABLE:
744 		d = PROC_PROTMAX_FORCE_ENABLE;
745 		break;
746 	case P2_PROTMAX_DISABLE:
747 		d = PROC_PROTMAX_FORCE_DISABLE;
748 		break;
749 	}
750 	if (kern_mmap_maxprot(p, PROT_READ) == PROT_READ)
751 		d |= PROC_PROTMAX_ACTIVE;
752 	*(int *)data = d;
753 	return (0);
754 }
755 
756 static int
757 aslr_ctl(struct thread *td, struct proc *p, void *data)
758 {
759 	int state;
760 
761 	PROC_LOCK_ASSERT(p, MA_OWNED);
762 	state = *(int *)data;
763 
764 	switch (state) {
765 	case PROC_ASLR_FORCE_ENABLE:
766 		p->p_flag2 &= ~P2_ASLR_DISABLE;
767 		p->p_flag2 |= P2_ASLR_ENABLE;
768 		break;
769 	case PROC_ASLR_FORCE_DISABLE:
770 		p->p_flag2 |= P2_ASLR_DISABLE;
771 		p->p_flag2 &= ~P2_ASLR_ENABLE;
772 		break;
773 	case PROC_ASLR_NOFORCE:
774 		p->p_flag2 &= ~(P2_ASLR_ENABLE | P2_ASLR_DISABLE);
775 		break;
776 	default:
777 		return (EINVAL);
778 	}
779 	return (0);
780 }
781 
782 static int
783 aslr_status(struct thread *td, struct proc *p, void *data)
784 {
785 	struct vmspace *vm;
786 	int d;
787 
788 	switch (p->p_flag2 & (P2_ASLR_ENABLE | P2_ASLR_DISABLE)) {
789 	case 0:
790 		d = PROC_ASLR_NOFORCE;
791 		break;
792 	case P2_ASLR_ENABLE:
793 		d = PROC_ASLR_FORCE_ENABLE;
794 		break;
795 	case P2_ASLR_DISABLE:
796 		d = PROC_ASLR_FORCE_DISABLE;
797 		break;
798 	}
799 	if ((p->p_flag & P_WEXIT) == 0) {
800 		_PHOLD(p);
801 		PROC_UNLOCK(p);
802 		vm = vmspace_acquire_ref(p);
803 		if (vm != NULL) {
804 			if ((vm->vm_map.flags & MAP_ASLR) != 0)
805 				d |= PROC_ASLR_ACTIVE;
806 			vmspace_free(vm);
807 		}
808 		PROC_LOCK(p);
809 		_PRELE(p);
810 	}
811 	*(int *)data = d;
812 	return (0);
813 }
814 
815 static int
816 stackgap_ctl(struct thread *td, struct proc *p, void *data)
817 {
818 	int state;
819 
820 	PROC_LOCK_ASSERT(p, MA_OWNED);
821 	state = *(int *)data;
822 
823 	if ((state & ~(PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE |
824 	    PROC_STACKGAP_ENABLE_EXEC | PROC_STACKGAP_DISABLE_EXEC)) != 0)
825 		return (EINVAL);
826 	switch (state & (PROC_STACKGAP_ENABLE | PROC_STACKGAP_DISABLE)) {
827 	case PROC_STACKGAP_ENABLE:
828 		if ((p->p_flag2 & P2_STKGAP_DISABLE) != 0)
829 			return (EINVAL);
830 		break;
831 	case PROC_STACKGAP_DISABLE:
832 		p->p_flag2 |= P2_STKGAP_DISABLE;
833 		break;
834 	case 0:
835 		break;
836 	default:
837 		return (EINVAL);
838 	}
839 	switch (state & (PROC_STACKGAP_ENABLE_EXEC |
840 	    PROC_STACKGAP_DISABLE_EXEC)) {
841 	case PROC_STACKGAP_ENABLE_EXEC:
842 		p->p_flag2 &= ~P2_STKGAP_DISABLE_EXEC;
843 		break;
844 	case PROC_STACKGAP_DISABLE_EXEC:
845 		p->p_flag2 |= P2_STKGAP_DISABLE_EXEC;
846 		break;
847 	case 0:
848 		break;
849 	default:
850 		return (EINVAL);
851 	}
852 	return (0);
853 }
854 
855 static int
856 stackgap_status(struct thread *td, struct proc *p, void *data)
857 {
858 	int d;
859 
860 	PROC_LOCK_ASSERT(p, MA_OWNED);
861 
862 	d = (p->p_flag2 & P2_STKGAP_DISABLE) != 0 ? PROC_STACKGAP_DISABLE :
863 	    PROC_STACKGAP_ENABLE;
864 	d |= (p->p_flag2 & P2_STKGAP_DISABLE_EXEC) != 0 ?
865 	    PROC_STACKGAP_DISABLE_EXEC : PROC_STACKGAP_ENABLE_EXEC;
866 	*(int *)data = d;
867 	return (0);
868 }
869 
870 static int
871 wxmap_ctl(struct thread *td, struct proc *p, void *data)
872 {
873 	struct vmspace *vm;
874 	vm_map_t map;
875 	int state;
876 
877 	PROC_LOCK_ASSERT(p, MA_OWNED);
878 	if ((p->p_flag & P_WEXIT) != 0)
879 		return (ESRCH);
880 	state = *(int *)data;
881 
882 	switch (state) {
883 	case PROC_WX_MAPPINGS_PERMIT:
884 		p->p_flag2 |= P2_WXORX_DISABLE;
885 		_PHOLD(p);
886 		PROC_UNLOCK(p);
887 		vm = vmspace_acquire_ref(p);
888 		if (vm != NULL) {
889 			map = &vm->vm_map;
890 			vm_map_lock(map);
891 			map->flags &= ~MAP_WXORX;
892 			vm_map_unlock(map);
893 			vmspace_free(vm);
894 		}
895 		PROC_LOCK(p);
896 		_PRELE(p);
897 		break;
898 	case PROC_WX_MAPPINGS_DISALLOW_EXEC:
899 		p->p_flag2 |= P2_WXORX_ENABLE_EXEC;
900 		break;
901 	default:
902 		return (EINVAL);
903 	}
904 
905 	return (0);
906 }
907 
908 static int
909 wxmap_status(struct thread *td, struct proc *p, void *data)
910 {
911 	struct vmspace *vm;
912 	int d;
913 
914 	PROC_LOCK_ASSERT(p, MA_OWNED);
915 	if ((p->p_flag & P_WEXIT) != 0)
916 		return (ESRCH);
917 
918 	d = 0;
919 	if ((p->p_flag2 & P2_WXORX_DISABLE) != 0)
920 		d |= PROC_WX_MAPPINGS_PERMIT;
921 	if ((p->p_flag2 & P2_WXORX_ENABLE_EXEC) != 0)
922 		d |= PROC_WX_MAPPINGS_DISALLOW_EXEC;
923 	_PHOLD(p);
924 	PROC_UNLOCK(p);
925 	vm = vmspace_acquire_ref(p);
926 	if (vm != NULL) {
927 		if ((vm->vm_map.flags & MAP_WXORX) != 0)
928 			d |= PROC_WXORX_ENFORCE;
929 		vmspace_free(vm);
930 	}
931 	PROC_LOCK(p);
932 	_PRELE(p);
933 	*(int *)data = d;
934 	return (0);
935 }
936 
937 static int
938 pdeathsig_ctl(struct thread *td, struct proc *p, void *data)
939 {
940 	int signum;
941 
942 	signum = *(int *)data;
943 	if (p != td->td_proc || (signum != 0 && !_SIG_VALID(signum)))
944 		return (EINVAL);
945 	p->p_pdeathsig = signum;
946 	return (0);
947 }
948 
949 static int
950 pdeathsig_status(struct thread *td, struct proc *p, void *data)
951 {
952 	if (p != td->td_proc)
953 		return (EINVAL);
954 	*(int *)data = p->p_pdeathsig;
955 	return (0);
956 }
957 
958 enum {
959 	PCTL_SLOCKED,
960 	PCTL_XLOCKED,
961 	PCTL_UNLOCKED,
962 };
963 
964 struct procctl_cmd_info {
965 	int lock_tree;
966 	bool one_proc : 1;
967 	bool esrch_is_einval : 1;
968 	bool copyout_on_error : 1;
969 	bool no_nonnull_data : 1;
970 	bool need_candebug : 1;
971 	int copyin_sz;
972 	int copyout_sz;
973 	int (*exec)(struct thread *, struct proc *, void *);
974 	bool (*sapblk)(struct thread *, void *);
975 };
976 static const struct procctl_cmd_info procctl_cmds_info[] = {
977 	[PROC_SPROTECT] =
978 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
979 	      .esrch_is_einval = false, .no_nonnull_data = false,
980 	      .need_candebug = false,
981 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
982 	      .exec = protect_set, .copyout_on_error = false, },
983 	[PROC_REAP_ACQUIRE] =
984 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
985 	      .esrch_is_einval = false, .no_nonnull_data = true,
986 	      .need_candebug = false,
987 	      .copyin_sz = 0, .copyout_sz = 0,
988 	      .exec = reap_acquire, .copyout_on_error = false, },
989 	[PROC_REAP_RELEASE] =
990 	    { .lock_tree = PCTL_XLOCKED, .one_proc = true,
991 	      .esrch_is_einval = false, .no_nonnull_data = true,
992 	      .need_candebug = false,
993 	      .copyin_sz = 0, .copyout_sz = 0,
994 	      .exec = reap_release, .copyout_on_error = false, },
995 	[PROC_REAP_STATUS] =
996 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
997 	      .esrch_is_einval = false, .no_nonnull_data = false,
998 	      .need_candebug = false,
999 	      .copyin_sz = 0,
1000 	      .copyout_sz = sizeof(struct procctl_reaper_status),
1001 	      .exec = reap_status, .copyout_on_error = false, },
1002 	[PROC_REAP_GETPIDS] =
1003 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1004 	      .esrch_is_einval = false, .no_nonnull_data = false,
1005 	      .need_candebug = false,
1006 	      .copyin_sz = sizeof(struct procctl_reaper_pids),
1007 	      .copyout_sz = 0,
1008 	      .exec = reap_getpids, .copyout_on_error = false, },
1009 	[PROC_REAP_KILL] =
1010 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1011 	      .esrch_is_einval = false, .no_nonnull_data = false,
1012 	      .need_candebug = false,
1013 	      .copyin_sz = sizeof(struct procctl_reaper_kill),
1014 	      .copyout_sz = sizeof(struct procctl_reaper_kill),
1015 	      .exec = reap_kill, .copyout_on_error = true,
1016 	      .sapblk = reap_kill_sapblk, },
1017 	[PROC_TRACE_CTL] =
1018 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1019 	      .esrch_is_einval = false, .no_nonnull_data = false,
1020 	      .need_candebug = true,
1021 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1022 	      .exec = trace_ctl, .copyout_on_error = false, },
1023 	[PROC_TRACE_STATUS] =
1024 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1025 	      .esrch_is_einval = false, .no_nonnull_data = false,
1026 	      .need_candebug = false,
1027 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1028 	      .exec = trace_status, .copyout_on_error = false, },
1029 	[PROC_TRAPCAP_CTL] =
1030 	    { .lock_tree = PCTL_SLOCKED, .one_proc = false,
1031 	      .esrch_is_einval = false, .no_nonnull_data = false,
1032 	      .need_candebug = true,
1033 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1034 	      .exec = trapcap_ctl, .copyout_on_error = false, },
1035 	[PROC_TRAPCAP_STATUS] =
1036 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1037 	      .esrch_is_einval = false, .no_nonnull_data = false,
1038 	      .need_candebug = false,
1039 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1040 	      .exec = trapcap_status, .copyout_on_error = false, },
1041 	[PROC_PDEATHSIG_CTL] =
1042 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1043 	      .esrch_is_einval = true, .no_nonnull_data = false,
1044 	      .need_candebug = false,
1045 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1046 	      .exec = pdeathsig_ctl, .copyout_on_error = false, },
1047 	[PROC_PDEATHSIG_STATUS] =
1048 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1049 	      .esrch_is_einval = true, .no_nonnull_data = false,
1050 	      .need_candebug = false,
1051 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1052 	      .exec = pdeathsig_status, .copyout_on_error = false, },
1053 	[PROC_ASLR_CTL] =
1054 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1055 	      .esrch_is_einval = false, .no_nonnull_data = false,
1056 	      .need_candebug = true,
1057 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1058 	      .exec = aslr_ctl, .copyout_on_error = false, },
1059 	[PROC_ASLR_STATUS] =
1060 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1061 	      .esrch_is_einval = false, .no_nonnull_data = false,
1062 	      .need_candebug = false,
1063 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1064 	      .exec = aslr_status, .copyout_on_error = false, },
1065 	[PROC_PROTMAX_CTL] =
1066 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1067 	      .esrch_is_einval = false, .no_nonnull_data = false,
1068 	      .need_candebug = true,
1069 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1070 	      .exec = protmax_ctl, .copyout_on_error = false, },
1071 	[PROC_PROTMAX_STATUS] =
1072 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1073 	      .esrch_is_einval = false, .no_nonnull_data = false,
1074 	      .need_candebug = false,
1075 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1076 	      .exec = protmax_status, .copyout_on_error = false, },
1077 	[PROC_STACKGAP_CTL] =
1078 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1079 	      .esrch_is_einval = false, .no_nonnull_data = false,
1080 	      .need_candebug = true,
1081 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1082 	      .exec = stackgap_ctl, .copyout_on_error = false, },
1083 	[PROC_STACKGAP_STATUS] =
1084 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1085 	      .esrch_is_einval = false, .no_nonnull_data = false,
1086 	      .need_candebug = false,
1087 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1088 	      .exec = stackgap_status, .copyout_on_error = false, },
1089 	[PROC_NO_NEW_PRIVS_CTL] =
1090 	    { .lock_tree = PCTL_SLOCKED, .one_proc = true,
1091 	      .esrch_is_einval = false, .no_nonnull_data = false,
1092 	      .need_candebug = true,
1093 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1094 	      .exec = no_new_privs_ctl, .copyout_on_error = false, },
1095 	[PROC_NO_NEW_PRIVS_STATUS] =
1096 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1097 	      .esrch_is_einval = false, .no_nonnull_data = false,
1098 	      .need_candebug = false,
1099 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1100 	      .exec = no_new_privs_status, .copyout_on_error = false, },
1101 	[PROC_WXMAP_CTL] =
1102 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1103 	      .esrch_is_einval = false, .no_nonnull_data = false,
1104 	      .need_candebug = true,
1105 	      .copyin_sz = sizeof(int), .copyout_sz = 0,
1106 	      .exec = wxmap_ctl, .copyout_on_error = false, },
1107 	[PROC_WXMAP_STATUS] =
1108 	    { .lock_tree = PCTL_UNLOCKED, .one_proc = true,
1109 	      .esrch_is_einval = false, .no_nonnull_data = false,
1110 	      .need_candebug = false,
1111 	      .copyin_sz = 0, .copyout_sz = sizeof(int),
1112 	      .exec = wxmap_status, .copyout_on_error = false, },
1113 };
1114 
1115 int
1116 sys_procctl(struct thread *td, struct procctl_args *uap)
1117 {
1118 	union {
1119 		struct procctl_reaper_status rs;
1120 		struct procctl_reaper_pids rp;
1121 		struct procctl_reaper_kill rk;
1122 		int flags;
1123 	} x;
1124 	const struct procctl_cmd_info *cmd_info;
1125 	int error, error1;
1126 
1127 	if (uap->com >= PROC_PROCCTL_MD_MIN)
1128 		return (cpu_procctl(td, uap->idtype, uap->id,
1129 		    uap->com, uap->data));
1130 	if (uap->com <= 0 || uap->com >= nitems(procctl_cmds_info))
1131 		return (EINVAL);
1132 	cmd_info = &procctl_cmds_info[uap->com];
1133 	bzero(&x, sizeof(x));
1134 
1135 	if (cmd_info->copyin_sz > 0) {
1136 		error = copyin(uap->data, &x, cmd_info->copyin_sz);
1137 		if (error != 0)
1138 			return (error);
1139 	} else if (cmd_info->no_nonnull_data && uap->data != NULL) {
1140 		return (EINVAL);
1141 	}
1142 
1143 	error = kern_procctl(td, uap->idtype, uap->id, uap->com, &x);
1144 
1145 	if (cmd_info->copyout_sz > 0 && (error == 0 ||
1146 	    cmd_info->copyout_on_error)) {
1147 		error1 = copyout(&x, uap->data, cmd_info->copyout_sz);
1148 		if (error == 0)
1149 			error = error1;
1150 	}
1151 	return (error);
1152 }
1153 
1154 static int
1155 kern_procctl_single(struct thread *td, struct proc *p, int com, void *data)
1156 {
1157 
1158 	PROC_LOCK_ASSERT(p, MA_OWNED);
1159 	return (procctl_cmds_info[com].exec(td, p, data));
1160 }
1161 
1162 int
1163 kern_procctl(struct thread *td, idtype_t idtype, id_t id, int com, void *data)
1164 {
1165 	struct pgrp *pg;
1166 	struct proc *p;
1167 	const struct procctl_cmd_info *cmd_info;
1168 	int error, first_error, ok;
1169 	bool sapblk;
1170 
1171 	MPASS(com > 0 && com < nitems(procctl_cmds_info));
1172 	cmd_info = &procctl_cmds_info[com];
1173 	if (idtype != P_PID && cmd_info->one_proc)
1174 		return (EINVAL);
1175 
1176 	sapblk = false;
1177 	if (cmd_info->sapblk != NULL) {
1178 		sapblk = cmd_info->sapblk(td, data);
1179 		if (sapblk && !stop_all_proc_block())
1180 			return (ERESTART);
1181 	}
1182 
1183 	switch (cmd_info->lock_tree) {
1184 	case PCTL_XLOCKED:
1185 		sx_xlock(&proctree_lock);
1186 		break;
1187 	case PCTL_SLOCKED:
1188 		sx_slock(&proctree_lock);
1189 		break;
1190 	default:
1191 		break;
1192 	}
1193 
1194 	switch (idtype) {
1195 	case P_PID:
1196 		if (id == 0) {
1197 			p = td->td_proc;
1198 			error = 0;
1199 			PROC_LOCK(p);
1200 		} else {
1201 			p = pfind(id);
1202 			if (p == NULL) {
1203 				error = cmd_info->esrch_is_einval ?
1204 				    EINVAL : ESRCH;
1205 				break;
1206 			}
1207 			error = cmd_info->need_candebug ? p_candebug(td, p) :
1208 			    p_cansee(td, p);
1209 		}
1210 		if (error == 0)
1211 			error = kern_procctl_single(td, p, com, data);
1212 		PROC_UNLOCK(p);
1213 		break;
1214 	case P_PGID:
1215 		/*
1216 		 * Attempt to apply the operation to all members of the
1217 		 * group.  Ignore processes in the group that can't be
1218 		 * seen.  Ignore errors so long as at least one process is
1219 		 * able to complete the request successfully.
1220 		 */
1221 		pg = pgfind(id);
1222 		if (pg == NULL) {
1223 			error = ESRCH;
1224 			break;
1225 		}
1226 		PGRP_UNLOCK(pg);
1227 		ok = 0;
1228 		first_error = 0;
1229 		LIST_FOREACH(p, &pg->pg_members, p_pglist) {
1230 			PROC_LOCK(p);
1231 			if (p->p_state == PRS_NEW ||
1232 			    p->p_state == PRS_ZOMBIE ||
1233 			    (cmd_info->need_candebug ? p_candebug(td, p) :
1234 			    p_cansee(td, p)) != 0) {
1235 				PROC_UNLOCK(p);
1236 				continue;
1237 			}
1238 			error = kern_procctl_single(td, p, com, data);
1239 			PROC_UNLOCK(p);
1240 			if (error == 0)
1241 				ok = 1;
1242 			else if (first_error == 0)
1243 				first_error = error;
1244 		}
1245 		if (ok)
1246 			error = 0;
1247 		else if (first_error != 0)
1248 			error = first_error;
1249 		else
1250 			/*
1251 			 * Was not able to see any processes in the
1252 			 * process group.
1253 			 */
1254 			error = ESRCH;
1255 		break;
1256 	default:
1257 		error = EINVAL;
1258 		break;
1259 	}
1260 
1261 	switch (cmd_info->lock_tree) {
1262 	case PCTL_XLOCKED:
1263 		sx_xunlock(&proctree_lock);
1264 		break;
1265 	case PCTL_SLOCKED:
1266 		sx_sunlock(&proctree_lock);
1267 		break;
1268 	default:
1269 		break;
1270 	}
1271 	if (sapblk)
1272 		stop_all_proc_unblock();
1273 	return (error);
1274 }
1275