xref: /dragonfly/sys/kern/kern_proc.c (revision e8364298)
1 /*
2  * Copyright (c) 1982, 1986, 1989, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)kern_proc.c	8.7 (Berkeley) 2/14/95
34  * $FreeBSD: src/sys/kern/kern_proc.c,v 1.63.2.9 2003/05/08 07:47:16 kbyanc Exp $
35  * $DragonFly: src/sys/kern/kern_proc.c,v 1.15 2004/06/10 22:11:35 dillon Exp $
36  */
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kernel.h>
41 #include <sys/sysctl.h>
42 #include <sys/malloc.h>
43 #include <sys/proc.h>
44 #include <sys/filedesc.h>
45 #include <sys/tty.h>
46 #include <sys/signalvar.h>
47 #include <vm/vm.h>
48 #include <sys/lock.h>
49 #include <vm/pmap.h>
50 #include <vm/vm_map.h>
51 #include <sys/user.h>
52 #include <vm/vm_zone.h>
53 #include <machine/smp.h>
54 
55 static MALLOC_DEFINE(M_PGRP, "pgrp", "process group header");
56 MALLOC_DEFINE(M_SESSION, "session", "session header");
57 static MALLOC_DEFINE(M_PROC, "proc", "Proc structures");
58 MALLOC_DEFINE(M_SUBPROC, "subproc", "Proc sub-structures");
59 
60 int ps_showallprocs = 1;
61 static int ps_showallthreads = 1;
62 SYSCTL_INT(_kern, OID_AUTO, ps_showallprocs, CTLFLAG_RW,
63     &ps_showallprocs, 0, "");
64 SYSCTL_INT(_kern, OID_AUTO, ps_showallthreads, CTLFLAG_RW,
65     &ps_showallthreads, 0, "");
66 
67 static void pgdelete	(struct pgrp *);
68 
69 static void	orphanpg (struct pgrp *pg);
70 
71 /*
72  * Other process lists
73  */
74 struct pidhashhead *pidhashtbl;
75 u_long pidhash;
76 struct pgrphashhead *pgrphashtbl;
77 u_long pgrphash;
78 struct proclist allproc;
79 struct proclist zombproc;
80 vm_zone_t proc_zone;
81 vm_zone_t thread_zone;
82 
83 /*
84  * Initialize global process hashing structures.
85  */
86 void
87 procinit()
88 {
89 
90 	LIST_INIT(&allproc);
91 	LIST_INIT(&zombproc);
92 	pidhashtbl = hashinit(maxproc / 4, M_PROC, &pidhash);
93 	pgrphashtbl = hashinit(maxproc / 4, M_PROC, &pgrphash);
94 	proc_zone = zinit("PROC", sizeof (struct proc), 0, 0, 5);
95 	thread_zone = zinit("THREAD", sizeof (struct thread), 0, 0, 5);
96 	uihashinit();
97 }
98 
99 /*
100  * Is p an inferior of the current process?
101  */
102 int
103 inferior(p)
104 	struct proc *p;
105 {
106 
107 	for (; p != curproc; p = p->p_pptr)
108 		if (p->p_pid == 0)
109 			return (0);
110 	return (1);
111 }
112 
113 /*
114  * Locate a process by number
115  */
116 struct proc *
117 pfind(pid)
118 	pid_t pid;
119 {
120 	struct proc *p;
121 
122 	LIST_FOREACH(p, PIDHASH(pid), p_hash)
123 		if (p->p_pid == pid)
124 			return (p);
125 	return (NULL);
126 }
127 
128 /*
129  * Locate a process group by number
130  */
131 struct pgrp *
132 pgfind(pgid)
133 	pid_t pgid;
134 {
135 	struct pgrp *pgrp;
136 
137 	LIST_FOREACH(pgrp, PGRPHASH(pgid), pg_hash)
138 		if (pgrp->pg_id == pgid)
139 			return (pgrp);
140 	return (NULL);
141 }
142 
143 /*
144  * Move p to a new or existing process group (and session)
145  */
146 int
147 enterpgrp(p, pgid, mksess)
148 	struct proc *p;
149 	pid_t pgid;
150 	int mksess;
151 {
152 	struct pgrp *pgrp = pgfind(pgid);
153 
154 	KASSERT(pgrp == NULL || !mksess,
155 	    ("enterpgrp: setsid into non-empty pgrp"));
156 	KASSERT(!SESS_LEADER(p),
157 	    ("enterpgrp: session leader attempted setpgrp"));
158 
159 	if (pgrp == NULL) {
160 		pid_t savepid = p->p_pid;
161 		struct proc *np;
162 		/*
163 		 * new process group
164 		 */
165 		KASSERT(p->p_pid == pgid,
166 		    ("enterpgrp: new pgrp and pid != pgid"));
167 		if ((np = pfind(savepid)) == NULL || np != p)
168 			return (ESRCH);
169 		MALLOC(pgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP,
170 		    M_WAITOK);
171 		if (mksess) {
172 			struct session *sess;
173 
174 			/*
175 			 * new session
176 			 */
177 			MALLOC(sess, struct session *, sizeof(struct session),
178 			    M_SESSION, M_WAITOK);
179 			sess->s_leader = p;
180 			sess->s_sid = p->p_pid;
181 			sess->s_count = 1;
182 			sess->s_ttyvp = NULL;
183 			sess->s_ttyp = NULL;
184 			bcopy(p->p_session->s_login, sess->s_login,
185 			    sizeof(sess->s_login));
186 			p->p_flag &= ~P_CONTROLT;
187 			pgrp->pg_session = sess;
188 			KASSERT(p == curproc,
189 			    ("enterpgrp: mksession and p != curproc"));
190 		} else {
191 			pgrp->pg_session = p->p_session;
192 			pgrp->pg_session->s_count++;
193 		}
194 		pgrp->pg_id = pgid;
195 		LIST_INIT(&pgrp->pg_members);
196 		LIST_INSERT_HEAD(PGRPHASH(pgid), pgrp, pg_hash);
197 		pgrp->pg_jobc = 0;
198 		SLIST_INIT(&pgrp->pg_sigiolst);
199 	} else if (pgrp == p->p_pgrp)
200 		return (0);
201 
202 	/*
203 	 * Adjust eligibility of affected pgrps to participate in job control.
204 	 * Increment eligibility counts before decrementing, otherwise we
205 	 * could reach 0 spuriously during the first call.
206 	 */
207 	fixjobc(p, pgrp, 1);
208 	fixjobc(p, p->p_pgrp, 0);
209 
210 	LIST_REMOVE(p, p_pglist);
211 	if (LIST_EMPTY(&p->p_pgrp->pg_members))
212 		pgdelete(p->p_pgrp);
213 	p->p_pgrp = pgrp;
214 	LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist);
215 	return (0);
216 }
217 
218 /*
219  * remove process from process group
220  */
221 int
222 leavepgrp(p)
223 	struct proc *p;
224 {
225 
226 	LIST_REMOVE(p, p_pglist);
227 	if (LIST_EMPTY(&p->p_pgrp->pg_members))
228 		pgdelete(p->p_pgrp);
229 	p->p_pgrp = 0;
230 	return (0);
231 }
232 
233 /*
234  * delete a process group
235  */
236 static void
237 pgdelete(pgrp)
238 	struct pgrp *pgrp;
239 {
240 
241 	/*
242 	 * Reset any sigio structures pointing to us as a result of
243 	 * F_SETOWN with our pgid.
244 	 */
245 	funsetownlst(&pgrp->pg_sigiolst);
246 
247 	if (pgrp->pg_session->s_ttyp != NULL &&
248 	    pgrp->pg_session->s_ttyp->t_pgrp == pgrp)
249 		pgrp->pg_session->s_ttyp->t_pgrp = NULL;
250 	LIST_REMOVE(pgrp, pg_hash);
251 	if (--pgrp->pg_session->s_count == 0)
252 		FREE(pgrp->pg_session, M_SESSION);
253 	FREE(pgrp, M_PGRP);
254 }
255 
256 /*
257  * Adjust pgrp jobc counters when specified process changes process group.
258  * We count the number of processes in each process group that "qualify"
259  * the group for terminal job control (those with a parent in a different
260  * process group of the same session).  If that count reaches zero, the
261  * process group becomes orphaned.  Check both the specified process'
262  * process group and that of its children.
263  * entering == 0 => p is leaving specified group.
264  * entering == 1 => p is entering specified group.
265  */
266 void
267 fixjobc(p, pgrp, entering)
268 	struct proc *p;
269 	struct pgrp *pgrp;
270 	int entering;
271 {
272 	struct pgrp *hispgrp;
273 	struct session *mysession = pgrp->pg_session;
274 
275 	/*
276 	 * Check p's parent to see whether p qualifies its own process
277 	 * group; if so, adjust count for p's process group.
278 	 */
279 	if ((hispgrp = p->p_pptr->p_pgrp) != pgrp &&
280 	    hispgrp->pg_session == mysession) {
281 		if (entering)
282 			pgrp->pg_jobc++;
283 		else if (--pgrp->pg_jobc == 0)
284 			orphanpg(pgrp);
285 	}
286 
287 	/*
288 	 * Check this process' children to see whether they qualify
289 	 * their process groups; if so, adjust counts for children's
290 	 * process groups.
291 	 */
292 	LIST_FOREACH(p, &p->p_children, p_sibling)
293 		if ((hispgrp = p->p_pgrp) != pgrp &&
294 		    hispgrp->pg_session == mysession &&
295 		    p->p_stat != SZOMB) {
296 			if (entering)
297 				hispgrp->pg_jobc++;
298 			else if (--hispgrp->pg_jobc == 0)
299 				orphanpg(hispgrp);
300 		}
301 }
302 
303 /*
304  * A process group has become orphaned;
305  * if there are any stopped processes in the group,
306  * hang-up all process in that group.
307  */
308 static void
309 orphanpg(pg)
310 	struct pgrp *pg;
311 {
312 	struct proc *p;
313 
314 	LIST_FOREACH(p, &pg->pg_members, p_pglist) {
315 		if (p->p_stat == SSTOP) {
316 			LIST_FOREACH(p, &pg->pg_members, p_pglist) {
317 				psignal(p, SIGHUP);
318 				psignal(p, SIGCONT);
319 			}
320 			return;
321 		}
322 	}
323 }
324 
325 #include "opt_ddb.h"
326 #ifdef DDB
327 #include <ddb/ddb.h>
328 
329 DB_SHOW_COMMAND(pgrpdump, pgrpdump)
330 {
331 	struct pgrp *pgrp;
332 	struct proc *p;
333 	int i;
334 
335 	for (i = 0; i <= pgrphash; i++) {
336 		if (!LIST_EMPTY(&pgrphashtbl[i])) {
337 			printf("\tindx %d\n", i);
338 			LIST_FOREACH(pgrp, &pgrphashtbl[i], pg_hash) {
339 				printf(
340 			"\tpgrp %p, pgid %ld, sess %p, sesscnt %d, mem %p\n",
341 				    (void *)pgrp, (long)pgrp->pg_id,
342 				    (void *)pgrp->pg_session,
343 				    pgrp->pg_session->s_count,
344 				    (void *)LIST_FIRST(&pgrp->pg_members));
345 				LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
346 					printf("\t\tpid %ld addr %p pgrp %p\n",
347 					    (long)p->p_pid, (void *)p,
348 					    (void *)p->p_pgrp);
349 				}
350 			}
351 		}
352 	}
353 }
354 #endif /* DDB */
355 
356 /*
357  * Fill in an eproc structure for the specified thread.
358  */
359 void
360 fill_eproc_td(thread_t td, struct eproc *ep, struct proc *xp)
361 {
362 	bzero(ep, sizeof(*ep));
363 
364 	ep->e_uticks = td->td_uticks;
365 	ep->e_sticks = td->td_sticks;
366 	ep->e_iticks = td->td_iticks;
367 	ep->e_tdev = NOUDEV;
368 	ep->e_cpuid = td->td_gd->gd_cpuid;
369 	if (td->td_wmesg) {
370 		strncpy(ep->e_wmesg, td->td_wmesg, WMESGLEN);
371 		ep->e_wmesg[WMESGLEN] = 0;
372 	}
373 
374 	/*
375 	 * Fake up portions of the proc structure copied out by the sysctl
376 	 * to return useful information.  Note that using td_pri directly
377 	 * is messy because it includes critial section data so we fake
378 	 * up an rtprio.prio for threads.
379 	 */
380 	if (xp) {
381 		*xp = *initproc;
382 		xp->p_rtprio.type = RTP_PRIO_THREAD;
383 		xp->p_rtprio.prio = td->td_pri & TDPRI_MASK;
384 		xp->p_pid = -1;
385 	}
386 }
387 
388 /*
389  * Fill in an eproc structure for the specified process.
390  */
391 void
392 fill_eproc(struct proc *p, struct eproc *ep)
393 {
394 	struct tty *tp;
395 
396 	fill_eproc_td(p->p_thread, ep, NULL);
397 
398 	ep->e_paddr = p;
399 	if (p->p_ucred) {
400 		ep->e_ucred = *p->p_ucred;
401 	}
402 	if (p->p_procsig) {
403 		ep->e_procsig = *p->p_procsig;
404 	}
405 	if (p->p_stat != SIDL && p->p_stat != SZOMB && p->p_vmspace != NULL) {
406 		struct vmspace *vm = p->p_vmspace;
407 		ep->e_vm = *vm;
408 		ep->e_vm.vm_rssize = vmspace_resident_count(vm); /*XXX*/
409 	}
410 	if ((p->p_flag & P_INMEM) && p->p_stats)
411 		ep->e_stats = *p->p_stats;
412 	if (p->p_pptr)
413 		ep->e_ppid = p->p_pptr->p_pid;
414 	if (p->p_pgrp) {
415 		ep->e_pgid = p->p_pgrp->pg_id;
416 		ep->e_jobc = p->p_pgrp->pg_jobc;
417 		ep->e_sess = p->p_pgrp->pg_session;
418 
419 		if (ep->e_sess) {
420 			bcopy(ep->e_sess->s_login, ep->e_login, sizeof(ep->e_login));
421 			if (ep->e_sess->s_ttyvp)
422 				ep->e_flag = EPROC_CTTY;
423 			if (p->p_session && SESS_LEADER(p))
424 				ep->e_flag |= EPROC_SLEADER;
425 		}
426 	}
427 	if ((p->p_flag & P_CONTROLT) &&
428 	    (ep->e_sess != NULL) &&
429 	    ((tp = ep->e_sess->s_ttyp) != NULL)) {
430 		ep->e_tdev = dev2udev(tp->t_dev);
431 		ep->e_tpgid = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PID;
432 		ep->e_tsess = tp->t_session;
433 	} else {
434 		ep->e_tdev = NOUDEV;
435 	}
436 }
437 
438 struct proc *
439 zpfind(pid_t pid)
440 {
441 	struct proc *p;
442 
443 	LIST_FOREACH(p, &zombproc, p_list)
444 		if (p->p_pid == pid)
445 			return (p);
446 	return (NULL);
447 }
448 
449 static int
450 sysctl_out_proc(struct proc *p, struct thread *td, struct sysctl_req *req, int doingzomb)
451 {
452 	struct eproc eproc;
453 	struct proc xproc;
454 	int error;
455 #if 0
456 	pid_t pid = p->p_pid;
457 #endif
458 
459 	if (p) {
460 		td = p->p_thread;
461 		fill_eproc(p, &eproc);
462 		xproc = *p;
463 
464 		/*
465 		 * Fixup p_stat from SRUN to SSLEEP if the process scheduler
466 		 * does not own the process and the thread scheduler says it
467 		 * isn't running or runnable.
468 		 *
469 		 * XXX temporary fix which might become permanent (I'd rather
470 		 * not pollute the thread scheduler with knowlege about
471 		 * processes).
472 		 */
473 		if ((p->p_flag & P_CP_RELEASED) && p->p_stat == SRUN &&
474 		    td && (td->td_flags & (TDF_RUNNING|TDF_RUNQ)) == 0
475 		) {
476 			xproc.p_stat = SSLEEP;
477 		}
478 	} else if (td) {
479 		fill_eproc_td(td, &eproc, &xproc);
480 	}
481 	error = SYSCTL_OUT(req,(caddr_t)&xproc, sizeof(struct proc));
482 	if (error)
483 		return (error);
484 	error = SYSCTL_OUT(req,(caddr_t)&eproc, sizeof(eproc));
485 	if (error)
486 		return (error);
487 	error = SYSCTL_OUT(req,(caddr_t)td, sizeof(struct thread));
488 	if (error)
489 		return (error);
490 #if 0
491 	if (!doingzomb && pid && (pfind(pid) != p))
492 		return EAGAIN;
493 	if (doingzomb && zpfind(pid) != p)
494 		return EAGAIN;
495 #endif
496 	return (0);
497 }
498 
499 static int
500 sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
501 {
502 	int *name = (int*) arg1;
503 	u_int namelen = arg2;
504 	struct proc *p;
505 	struct thread *td;
506 	int doingzomb;
507 	int error = 0;
508 	int n;
509 	int origcpu;
510 	struct ucred *cr1 = curproc->p_ucred;
511 
512 	if (oidp->oid_number == KERN_PROC_PID) {
513 		if (namelen != 1)
514 			return (EINVAL);
515 		p = pfind((pid_t)name[0]);
516 		if (!p)
517 			return (0);
518 		if (!PRISON_CHECK(cr1, p->p_ucred))
519 			return (0);
520 		error = sysctl_out_proc(p, NULL, req, 0);
521 		return (error);
522 	}
523 	if (oidp->oid_number == KERN_PROC_ALL && !namelen)
524 		;
525 	else if (oidp->oid_number != KERN_PROC_ALL && namelen == 1)
526 		;
527 	else
528 		return (EINVAL);
529 
530 	if (!req->oldptr) {
531 		/* overestimate by 5 procs */
532 		error = SYSCTL_OUT(req, 0, sizeof (struct kinfo_proc) * 5);
533 		if (error)
534 			return (error);
535 	}
536 	for (doingzomb=0 ; doingzomb < 2 ; doingzomb++) {
537 		if (!doingzomb)
538 			p = LIST_FIRST(&allproc);
539 		else
540 			p = LIST_FIRST(&zombproc);
541 		for (; p != 0; p = LIST_NEXT(p, p_list)) {
542 			/*
543 			 * Show a user only their processes.
544 			 */
545 			if ((!ps_showallprocs) && p_trespass(cr1, p->p_ucred))
546 				continue;
547 			/*
548 			 * Skip embryonic processes.
549 			 */
550 			if (p->p_stat == SIDL)
551 				continue;
552 			/*
553 			 * TODO - make more efficient (see notes below).
554 			 * do by session.
555 			 */
556 			switch (oidp->oid_number) {
557 			case KERN_PROC_PGRP:
558 				/* could do this by traversing pgrp */
559 				if (p->p_pgrp == NULL ||
560 				    p->p_pgrp->pg_id != (pid_t)name[0])
561 					continue;
562 				break;
563 
564 			case KERN_PROC_TTY:
565 				if ((p->p_flag & P_CONTROLT) == 0 ||
566 				    p->p_session == NULL ||
567 				    p->p_session->s_ttyp == NULL ||
568 				    dev2udev(p->p_session->s_ttyp->t_dev) !=
569 					(udev_t)name[0])
570 					continue;
571 				break;
572 
573 			case KERN_PROC_UID:
574 				if (p->p_ucred == NULL ||
575 				    p->p_ucred->cr_uid != (uid_t)name[0])
576 					continue;
577 				break;
578 
579 			case KERN_PROC_RUID:
580 				if (p->p_ucred == NULL ||
581 				    p->p_ucred->cr_ruid != (uid_t)name[0])
582 					continue;
583 				break;
584 			}
585 
586 			if (!PRISON_CHECK(cr1, p->p_ucred))
587 				continue;
588 			PHOLD(p);
589 			error = sysctl_out_proc(p, NULL, req, doingzomb);
590 			PRELE(p);
591 			if (error)
592 				return (error);
593 		}
594 	}
595 
596 	/*
597 	 * Iterate over all active cpus and scan their thread list.  Start
598 	 * with the next logical cpu and end with our original cpu.  We
599 	 * migrate our own thread to each target cpu in order to safely scan
600 	 * its thread list.  In the last loop we migrate back to our original
601 	 * cpu.
602 	 */
603 	origcpu = mycpu->gd_cpuid;
604 	for (n = 1; ps_showallthreads && n <= ncpus; ++n) {
605 		globaldata_t rgd;
606 		int nid;
607 
608 		nid = (origcpu + n) % ncpus;
609 		if ((smp_active_mask & (1 << nid)) == 0)
610 			continue;
611 		rgd = globaldata_find(nid);
612 		lwkt_setcpu_self(rgd);
613 		cpu_mb1();	/* CURRENT CPU HAS CHANGED */
614 
615 		TAILQ_FOREACH(td, &mycpu->gd_tdallq, td_allq) {
616 			if (td->td_proc)
617 				continue;
618 			switch (oidp->oid_number) {
619 			case KERN_PROC_PGRP:
620 			case KERN_PROC_TTY:
621 			case KERN_PROC_UID:
622 			case KERN_PROC_RUID:
623 				continue;
624 			default:
625 				break;
626 			}
627 			lwkt_hold(td);
628 			error = sysctl_out_proc(NULL, td, req, doingzomb);
629 			lwkt_rele(td);
630 			if (error)
631 				return (error);
632 		}
633 	}
634 	return (0);
635 }
636 
637 /*
638  * This sysctl allows a process to retrieve the argument list or process
639  * title for another process without groping around in the address space
640  * of the other process.  It also allow a process to set its own "process
641  * title to a string of its own choice.
642  */
643 static int
644 sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
645 {
646 	int *name = (int*) arg1;
647 	u_int namelen = arg2;
648 	struct proc *p;
649 	struct pargs *pa;
650 	int error = 0;
651 	struct ucred *cr1 = curproc->p_ucred;
652 
653 	if (namelen != 1)
654 		return (EINVAL);
655 
656 	p = pfind((pid_t)name[0]);
657 	if (!p)
658 		return (0);
659 
660 	if ((!ps_argsopen) && p_trespass(cr1, p->p_ucred))
661 		return (0);
662 
663 	if (req->newptr && curproc != p)
664 		return (EPERM);
665 
666 	if (req->oldptr && p->p_args != NULL)
667 		error = SYSCTL_OUT(req, p->p_args->ar_args, p->p_args->ar_length);
668 	if (req->newptr == NULL)
669 		return (error);
670 
671 	if (p->p_args && --p->p_args->ar_ref == 0)
672 		FREE(p->p_args, M_PARGS);
673 	p->p_args = NULL;
674 
675 	if (req->newlen + sizeof(struct pargs) > ps_arg_cache_limit)
676 		return (error);
677 
678 	MALLOC(pa, struct pargs *, sizeof(struct pargs) + req->newlen,
679 	    M_PARGS, M_WAITOK);
680 	pa->ar_ref = 1;
681 	pa->ar_length = req->newlen;
682 	error = SYSCTL_IN(req, pa->ar_args, req->newlen);
683 	if (!error)
684 		p->p_args = pa;
685 	else
686 		FREE(pa, M_PARGS);
687 	return (error);
688 }
689 
690 SYSCTL_NODE(_kern, KERN_PROC, proc, CTLFLAG_RD,  0, "Process table");
691 
692 SYSCTL_PROC(_kern_proc, KERN_PROC_ALL, all, CTLFLAG_RD|CTLTYPE_STRUCT,
693 	0, 0, sysctl_kern_proc, "S,proc", "Return entire process table");
694 
695 SYSCTL_NODE(_kern_proc, KERN_PROC_PGRP, pgrp, CTLFLAG_RD,
696 	sysctl_kern_proc, "Process table");
697 
698 SYSCTL_NODE(_kern_proc, KERN_PROC_TTY, tty, CTLFLAG_RD,
699 	sysctl_kern_proc, "Process table");
700 
701 SYSCTL_NODE(_kern_proc, KERN_PROC_UID, uid, CTLFLAG_RD,
702 	sysctl_kern_proc, "Process table");
703 
704 SYSCTL_NODE(_kern_proc, KERN_PROC_RUID, ruid, CTLFLAG_RD,
705 	sysctl_kern_proc, "Process table");
706 
707 SYSCTL_NODE(_kern_proc, KERN_PROC_PID, pid, CTLFLAG_RD,
708 	sysctl_kern_proc, "Process table");
709 
710 SYSCTL_NODE(_kern_proc, KERN_PROC_ARGS, args, CTLFLAG_RW | CTLFLAG_ANYBODY,
711 	sysctl_kern_proc_args, "Process argument list");
712