xref: /freebsd/sys/kern/kern_proc.c (revision 1a2cdef4962b47be5057809ce730a733b7f3c27c)
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  * $FreeBSD$
35  */
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/sysctl.h>
41 #include <sys/malloc.h>
42 #include <sys/proc.h>
43 #include <sys/filedesc.h>
44 #include <sys/tty.h>
45 #include <sys/signalvar.h>
46 #include <sys/sx.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 <sys/jail.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 SYSCTL_INT(_kern, OID_AUTO, ps_showallprocs, CTLFLAG_RW,
62     &ps_showallprocs, 0, "");
63 
64 static void pgdelete	__P((struct pgrp *));
65 
66 static void	orphanpg __P((struct pgrp *pg));
67 
68 /*
69  * Other process lists
70  */
71 struct pidhashhead *pidhashtbl;
72 u_long pidhash;
73 struct pgrphashhead *pgrphashtbl;
74 u_long pgrphash;
75 struct proclist allproc;
76 struct proclist zombproc;
77 struct sx allproc_lock;
78 struct sx proctree_lock;
79 vm_zone_t proc_zone;
80 vm_zone_t ithread_zone;
81 
82 /*
83  * Initialize global process hashing structures.
84  */
85 void
86 procinit()
87 {
88 	int i, j;
89 
90 	sx_init(&allproc_lock, "allproc");
91 	sx_init(&proctree_lock, "proctree");
92 	LIST_INIT(&allproc);
93 	LIST_INIT(&zombproc);
94 	pidhashtbl = hashinit(maxproc / 4, M_PROC, &pidhash);
95 	pgrphashtbl = hashinit(maxproc / 4, M_PROC, &pgrphash);
96 	proc_zone = zinit("PROC", sizeof (struct proc), 0, 0, 5);
97 	uihashinit();
98 	/*
99 	 * This should really be a compile time warning, but I do
100 	 * not know of any way to do that...
101 	 */
102 	if (sizeof(struct kinfo_proc) != KINFO_PROC_SIZE) {
103 		printf("This message will repeat for the next 20 seconds\n");
104 		for (i = 0; i < 20; i++) {
105 			printf("WARNING: size of kinfo_proc (%ld) should be %d!!!\n",
106 			    (long)sizeof(struct kinfo_proc), KINFO_PROC_SIZE);
107 			printf("The kinfo_proc structure was changed ");
108 			printf("incorrectly in <sys/user.h>\n");
109 			for (j = 0; j < 0x7ffffff; j++);
110 		}
111 
112 	}
113 }
114 
115 /*
116  * Is p an inferior of the current process?
117  */
118 int
119 inferior(p)
120 	register struct proc *p;
121 {
122 	int rval = 1;
123 
124 	sx_slock(&proctree_lock);
125 	for (; p != curproc; p = p->p_pptr)
126 		if (p->p_pid == 0) {
127 			rval = 0;
128 			break;
129 		}
130 	sx_sunlock(&proctree_lock);
131 	return (rval);
132 }
133 
134 /*
135  * Locate a process by number
136  */
137 struct proc *
138 pfind(pid)
139 	register pid_t pid;
140 {
141 	register struct proc *p;
142 
143 	sx_slock(&allproc_lock);
144 	LIST_FOREACH(p, PIDHASH(pid), p_hash)
145 		if (p->p_pid == pid)
146 			break;
147 	sx_sunlock(&allproc_lock);
148 	return (p);
149 }
150 
151 /*
152  * Locate a process group by number
153  */
154 struct pgrp *
155 pgfind(pgid)
156 	register pid_t pgid;
157 {
158 	register struct pgrp *pgrp;
159 
160 	LIST_FOREACH(pgrp, PGRPHASH(pgid), pg_hash)
161 		if (pgrp->pg_id == pgid)
162 			return (pgrp);
163 	return (NULL);
164 }
165 
166 /*
167  * Move p to a new or existing process group (and session)
168  */
169 int
170 enterpgrp(p, pgid, mksess)
171 	register struct proc *p;
172 	pid_t pgid;
173 	int mksess;
174 {
175 	register struct pgrp *pgrp = pgfind(pgid);
176 	struct pgrp *savegrp;
177 
178 	KASSERT(pgrp == NULL || !mksess,
179 	    ("enterpgrp: setsid into non-empty pgrp"));
180 	KASSERT(!SESS_LEADER(p),
181 	    ("enterpgrp: session leader attempted setpgrp"));
182 
183 	if (pgrp == NULL) {
184 		pid_t savepid = p->p_pid;
185 		struct proc *np;
186 		/*
187 		 * new process group
188 		 */
189 		KASSERT(p->p_pid == pgid,
190 		    ("enterpgrp: new pgrp and pid != pgid"));
191 		if ((np = pfind(savepid)) == NULL || np != p)
192 			return (ESRCH);
193 		MALLOC(pgrp, struct pgrp *, sizeof(struct pgrp), M_PGRP,
194 		    M_WAITOK);
195 		if (mksess) {
196 			register struct session *sess;
197 
198 			/*
199 			 * new session
200 			 */
201 			MALLOC(sess, struct session *, sizeof(struct session),
202 			    M_SESSION, M_WAITOK);
203 			sess->s_leader = p;
204 			sess->s_sid = p->p_pid;
205 			sess->s_count = 1;
206 			sess->s_ttyvp = NULL;
207 			sess->s_ttyp = NULL;
208 			bcopy(p->p_session->s_login, sess->s_login,
209 			    sizeof(sess->s_login));
210 			PROC_LOCK(p);
211 			p->p_flag &= ~P_CONTROLT;
212 			PROC_UNLOCK(p);
213 			pgrp->pg_session = sess;
214 			KASSERT(p == curproc,
215 			    ("enterpgrp: mksession and p != curproc"));
216 		} else {
217 			pgrp->pg_session = p->p_session;
218 			pgrp->pg_session->s_count++;
219 		}
220 		pgrp->pg_id = pgid;
221 		LIST_INIT(&pgrp->pg_members);
222 		LIST_INSERT_HEAD(PGRPHASH(pgid), pgrp, pg_hash);
223 		pgrp->pg_jobc = 0;
224 		SLIST_INIT(&pgrp->pg_sigiolst);
225 	} else if (pgrp == p->p_pgrp)
226 		return (0);
227 
228 	/*
229 	 * Adjust eligibility of affected pgrps to participate in job control.
230 	 * Increment eligibility counts before decrementing, otherwise we
231 	 * could reach 0 spuriously during the first call.
232 	 */
233 	fixjobc(p, pgrp, 1);
234 	fixjobc(p, p->p_pgrp, 0);
235 
236 	PROC_LOCK(p);
237 	LIST_REMOVE(p, p_pglist);
238 	savegrp = p->p_pgrp;
239 	p->p_pgrp = pgrp;
240 	LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist);
241 	PROC_UNLOCK(p);
242 	if (LIST_EMPTY(&savegrp->pg_members))
243 		pgdelete(savegrp);
244 	return (0);
245 }
246 
247 /*
248  * remove process from process group
249  */
250 int
251 leavepgrp(p)
252 	register struct proc *p;
253 {
254 	struct pgrp *savegrp;
255 
256 	PROC_LOCK(p);
257 	LIST_REMOVE(p, p_pglist);
258 	savegrp = p->p_pgrp;
259 	p->p_pgrp = NULL;
260 	PROC_UNLOCK(p);
261 	if (LIST_EMPTY(&savegrp->pg_members))
262 		pgdelete(savegrp);
263 	return (0);
264 }
265 
266 /*
267  * delete a process group
268  */
269 static void
270 pgdelete(pgrp)
271 	register struct pgrp *pgrp;
272 {
273 
274 	/*
275 	 * Reset any sigio structures pointing to us as a result of
276 	 * F_SETOWN with our pgid.
277 	 */
278 	funsetownlst(&pgrp->pg_sigiolst);
279 
280 	if (pgrp->pg_session->s_ttyp != NULL &&
281 	    pgrp->pg_session->s_ttyp->t_pgrp == pgrp)
282 		pgrp->pg_session->s_ttyp->t_pgrp = NULL;
283 	LIST_REMOVE(pgrp, pg_hash);
284 	if (--pgrp->pg_session->s_count == 0)
285 		FREE(pgrp->pg_session, M_SESSION);
286 	FREE(pgrp, M_PGRP);
287 }
288 
289 /*
290  * Adjust pgrp jobc counters when specified process changes process group.
291  * We count the number of processes in each process group that "qualify"
292  * the group for terminal job control (those with a parent in a different
293  * process group of the same session).  If that count reaches zero, the
294  * process group becomes orphaned.  Check both the specified process'
295  * process group and that of its children.
296  * entering == 0 => p is leaving specified group.
297  * entering == 1 => p is entering specified group.
298  */
299 void
300 fixjobc(p, pgrp, entering)
301 	register struct proc *p;
302 	register struct pgrp *pgrp;
303 	int entering;
304 {
305 	register struct pgrp *hispgrp;
306 	register struct session *mysession = pgrp->pg_session;
307 
308 	/*
309 	 * Check p's parent to see whether p qualifies its own process
310 	 * group; if so, adjust count for p's process group.
311 	 */
312 	sx_slock(&proctree_lock);
313 	if ((hispgrp = p->p_pptr->p_pgrp) != pgrp &&
314 	    hispgrp->pg_session == mysession) {
315 		if (entering)
316 			pgrp->pg_jobc++;
317 		else if (--pgrp->pg_jobc == 0)
318 			orphanpg(pgrp);
319 	}
320 
321 	/*
322 	 * Check this process' children to see whether they qualify
323 	 * their process groups; if so, adjust counts for children's
324 	 * process groups.
325 	 */
326 	LIST_FOREACH(p, &p->p_children, p_sibling)
327 		if ((hispgrp = p->p_pgrp) != pgrp &&
328 		    hispgrp->pg_session == mysession &&
329 		    p->p_stat != SZOMB) {
330 			if (entering)
331 				hispgrp->pg_jobc++;
332 			else if (--hispgrp->pg_jobc == 0)
333 				orphanpg(hispgrp);
334 		}
335 	sx_sunlock(&proctree_lock);
336 }
337 
338 /*
339  * A process group has become orphaned;
340  * if there are any stopped processes in the group,
341  * hang-up all process in that group.
342  */
343 static void
344 orphanpg(pg)
345 	struct pgrp *pg;
346 {
347 	register struct proc *p;
348 
349 	mtx_lock_spin(&sched_lock);
350 	LIST_FOREACH(p, &pg->pg_members, p_pglist) {
351 		if (p->p_stat == SSTOP) {
352 			mtx_unlock_spin(&sched_lock);
353 			LIST_FOREACH(p, &pg->pg_members, p_pglist) {
354 				PROC_LOCK(p);
355 				psignal(p, SIGHUP);
356 				psignal(p, SIGCONT);
357 				PROC_UNLOCK(p);
358 			}
359 			return;
360 		}
361 	}
362 	mtx_unlock_spin(&sched_lock);
363 }
364 
365 #include "opt_ddb.h"
366 #ifdef DDB
367 #include <ddb/ddb.h>
368 
369 DB_SHOW_COMMAND(pgrpdump, pgrpdump)
370 {
371 	register struct pgrp *pgrp;
372 	register struct proc *p;
373 	register int i;
374 
375 	for (i = 0; i <= pgrphash; i++) {
376 		if (!LIST_EMPTY(&pgrphashtbl[i])) {
377 			printf("\tindx %d\n", i);
378 			LIST_FOREACH(pgrp, &pgrphashtbl[i], pg_hash) {
379 				printf(
380 			"\tpgrp %p, pgid %ld, sess %p, sesscnt %d, mem %p\n",
381 				    (void *)pgrp, (long)pgrp->pg_id,
382 				    (void *)pgrp->pg_session,
383 				    pgrp->pg_session->s_count,
384 				    (void *)LIST_FIRST(&pgrp->pg_members));
385 				LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
386 					printf("\t\tpid %ld addr %p pgrp %p\n",
387 					    (long)p->p_pid, (void *)p,
388 					    (void *)p->p_pgrp);
389 				}
390 			}
391 		}
392 	}
393 }
394 #endif /* DDB */
395 
396 /*
397  * Fill in an kinfo_proc structure for the specified process.
398  */
399 void
400 fill_kinfo_proc(p, kp)
401 	struct proc *p;
402 	struct kinfo_proc *kp;
403 {
404 	struct tty *tp;
405 	struct session *sp;
406 
407 	bzero(kp, sizeof(*kp));
408 
409 	kp->ki_structsize = sizeof(*kp);
410 	kp->ki_paddr = p;
411 	PROC_LOCK(p);
412 	kp->ki_addr = p->p_addr;
413 	kp->ki_args = p->p_args;
414 	kp->ki_tracep = p->p_tracep;
415 	kp->ki_textvp = p->p_textvp;
416 	kp->ki_fd = p->p_fd;
417 	kp->ki_vmspace = p->p_vmspace;
418 	if (p->p_cred) {
419 		kp->ki_uid = p->p_cred->pc_ucred->cr_uid;
420 		kp->ki_ruid = p->p_cred->p_ruid;
421 		kp->ki_svuid = p->p_cred->p_svuid;
422 		kp->ki_ngroups = p->p_cred->pc_ucred->cr_ngroups;
423 		bcopy(p->p_cred->pc_ucred->cr_groups, kp->ki_groups,
424 		    NGROUPS * sizeof(gid_t));
425 		kp->ki_rgid = p->p_cred->p_rgid;
426 		kp->ki_svgid = p->p_cred->p_svgid;
427 	}
428 	if (p->p_procsig) {
429 		kp->ki_sigignore = p->p_procsig->ps_sigignore;
430 		kp->ki_sigcatch = p->p_procsig->ps_sigcatch;
431 	}
432 	mtx_lock_spin(&sched_lock);
433 	if (p->p_stat != SIDL && p->p_stat != SZOMB && p->p_vmspace != NULL) {
434 		struct vmspace *vm = p->p_vmspace;
435 
436 		kp->ki_size = vm->vm_map.size;
437 		kp->ki_rssize = vmspace_resident_count(vm); /*XXX*/
438 		kp->ki_swrss = vm->vm_swrss;
439 		kp->ki_tsize = vm->vm_tsize;
440 		kp->ki_dsize = vm->vm_dsize;
441 		kp->ki_ssize = vm->vm_ssize;
442 	}
443 	if ((p->p_sflag & PS_INMEM) && p->p_stats) {
444 		kp->ki_start = p->p_stats->p_start;
445 		kp->ki_rusage = p->p_stats->p_ru;
446 		kp->ki_childtime.tv_sec = p->p_stats->p_cru.ru_utime.tv_sec +
447 		    p->p_stats->p_cru.ru_stime.tv_sec;
448 		kp->ki_childtime.tv_usec = p->p_stats->p_cru.ru_utime.tv_usec +
449 		    p->p_stats->p_cru.ru_stime.tv_usec;
450 	}
451 	if (p->p_wmesg) {
452 		strncpy(kp->ki_wmesg, p->p_wmesg, WMESGLEN);
453 		kp->ki_wmesg[WMESGLEN] = 0;
454 	}
455 	if (p->p_stat == SMTX) {
456 		kp->ki_kiflag |= KI_MTXBLOCK;
457 		strncpy(kp->ki_mtxname, p->p_mtxname, MTXNAMELEN);
458 		kp->ki_mtxname[MTXNAMELEN] = 0;
459 	}
460 	kp->ki_stat = p->p_stat;
461 	kp->ki_sflag = p->p_sflag;
462 	kp->ki_pctcpu = p->p_pctcpu;
463 	kp->ki_estcpu = p->p_estcpu;
464 	kp->ki_slptime = p->p_slptime;
465 	kp->ki_swtime = p->p_swtime;
466 	kp->ki_wchan = p->p_wchan;
467 	kp->ki_traceflag = p->p_traceflag;
468 	kp->ki_pri = p->p_pri;
469 	kp->ki_nice = p->p_nice;
470 	kp->ki_runtime = p->p_runtime;
471 	kp->ki_pid = p->p_pid;
472 	kp->ki_rqindex = p->p_rqindex;
473 	kp->ki_oncpu = p->p_oncpu;
474 	kp->ki_lastcpu = p->p_lastcpu;
475 	mtx_unlock_spin(&sched_lock);
476 	sp = NULL;
477 	if (p->p_pgrp) {
478 		kp->ki_pgid = p->p_pgrp->pg_id;
479 		kp->ki_jobc = p->p_pgrp->pg_jobc;
480 		sp = p->p_pgrp->pg_session;
481 
482 		if (sp != NULL) {
483 			kp->ki_sid = sp->s_sid;
484 			bcopy(sp->s_login, kp->ki_login, sizeof(kp->ki_login));
485 			if (sp->s_ttyvp)
486 				kp->ki_kiflag = KI_CTTY;
487 			if (SESS_LEADER(p))
488 				kp->ki_kiflag |= KI_SLEADER;
489 		}
490 	}
491 	if ((p->p_flag & P_CONTROLT) && sp && ((tp = sp->s_ttyp) != NULL)) {
492 		kp->ki_tdev = dev2udev(tp->t_dev);
493 		kp->ki_tpgid = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PID;
494 		if (tp->t_session)
495 			kp->ki_tsid = tp->t_session->s_sid;
496 	} else
497 		kp->ki_tdev = NOUDEV;
498 	if (p->p_comm[0] != 0) {
499 		strncpy(kp->ki_comm, p->p_comm, MAXCOMLEN);
500 		kp->ki_comm[MAXCOMLEN] = 0;
501 	}
502 	kp->ki_siglist = p->p_siglist;
503 	kp->ki_sigmask = p->p_sigmask;
504 	kp->ki_xstat = p->p_xstat;
505 	kp->ki_acflag = p->p_acflag;
506 	kp->ki_flag = p->p_flag;
507 	/* If jailed(p->p_ucred), emulate the old P_JAILED flag. */
508 	if (jailed(p->p_ucred))
509 		kp->ki_flag |= P_JAILED;
510 	kp->ki_lock = p->p_lock;
511 	if (p->p_pptr)
512 		kp->ki_ppid = p->p_pptr->p_pid;
513 	PROC_UNLOCK(p);
514 }
515 
516 /*
517  * Locate a zombie process by number
518  */
519 struct proc *
520 zpfind(pid_t pid)
521 {
522 	struct proc *p;
523 
524 	sx_slock(&allproc_lock);
525 	LIST_FOREACH(p, &zombproc, p_list)
526 		if (p->p_pid == pid)
527 			break;
528 	sx_sunlock(&allproc_lock);
529 	return (p);
530 }
531 
532 
533 static int
534 sysctl_out_proc(struct proc *p, struct sysctl_req *req, int doingzomb)
535 {
536 	struct kinfo_proc kinfo_proc;
537 	int error;
538 	pid_t pid = p->p_pid;
539 
540 	fill_kinfo_proc(p, &kinfo_proc);
541 	error = SYSCTL_OUT(req, (caddr_t)&kinfo_proc, sizeof(kinfo_proc));
542 	if (error)
543 		return (error);
544 	if (!doingzomb && pid && (pfind(pid) != p))
545 		return EAGAIN;
546 	if (doingzomb && zpfind(pid) != p)
547 		return EAGAIN;
548 	return (0);
549 }
550 
551 static int
552 sysctl_kern_proc(SYSCTL_HANDLER_ARGS)
553 {
554 	int *name = (int*) arg1;
555 	u_int namelen = arg2;
556 	struct proc *p;
557 	int doingzomb;
558 	int error = 0;
559 
560 	if (oidp->oid_number == KERN_PROC_PID) {
561 		if (namelen != 1)
562 			return (EINVAL);
563 		p = pfind((pid_t)name[0]);
564 		if (!p)
565 			return (0);
566 		if (p_can(curproc, p, P_CAN_SEE, NULL))
567 			return (0);
568 		error = sysctl_out_proc(p, req, 0);
569 		return (error);
570 	}
571 	if (oidp->oid_number == KERN_PROC_ALL && !namelen)
572 		;
573 	else if (oidp->oid_number != KERN_PROC_ALL && namelen == 1)
574 		;
575 	else
576 		return (EINVAL);
577 
578 	if (!req->oldptr) {
579 		/* overestimate by 5 procs */
580 		error = SYSCTL_OUT(req, 0, sizeof (struct kinfo_proc) * 5);
581 		if (error)
582 			return (error);
583 	}
584 	sx_slock(&allproc_lock);
585 	for (doingzomb=0 ; doingzomb < 2 ; doingzomb++) {
586 		if (!doingzomb)
587 			p = LIST_FIRST(&allproc);
588 		else
589 			p = LIST_FIRST(&zombproc);
590 		for (; p != 0; p = LIST_NEXT(p, p_list)) {
591 			/*
592 			 * Show a user only appropriate processes.
593 			 */
594 			if (p_can(curproc, p, P_CAN_SEE, NULL))
595 				continue;
596 			/*
597 			 * Skip embryonic processes.
598 			 */
599 			if (p->p_stat == SIDL)
600 				continue;
601 			/*
602 			 * TODO - make more efficient (see notes below).
603 			 * do by session.
604 			 */
605 			switch (oidp->oid_number) {
606 
607 			case KERN_PROC_PGRP:
608 				/* could do this by traversing pgrp */
609 				if (p->p_pgrp == NULL ||
610 				    p->p_pgrp->pg_id != (pid_t)name[0])
611 					continue;
612 				break;
613 
614 			case KERN_PROC_TTY:
615 				if ((p->p_flag & P_CONTROLT) == 0 ||
616 				    p->p_session == NULL ||
617 				    p->p_session->s_ttyp == NULL ||
618 				    dev2udev(p->p_session->s_ttyp->t_dev) !=
619 					(udev_t)name[0])
620 					continue;
621 				break;
622 
623 			case KERN_PROC_UID:
624 				if (p->p_ucred == NULL ||
625 				    p->p_ucred->cr_uid != (uid_t)name[0])
626 					continue;
627 				break;
628 
629 			case KERN_PROC_RUID:
630 				if (p->p_ucred == NULL ||
631 				    p->p_cred->p_ruid != (uid_t)name[0])
632 					continue;
633 				break;
634 			}
635 
636 			if (p_can(curproc, p, P_CAN_SEE, NULL))
637 				continue;
638 
639 			error = sysctl_out_proc(p, req, doingzomb);
640 			if (error) {
641 				sx_sunlock(&allproc_lock);
642 				return (error);
643 			}
644 		}
645 	}
646 	sx_sunlock(&allproc_lock);
647 	return (0);
648 }
649 
650 /*
651  * This sysctl allows a process to retrieve the argument list or process
652  * title for another process without groping around in the address space
653  * of the other process.  It also allow a process to set its own "process
654  * title to a string of its own choice.
655  */
656 static int
657 sysctl_kern_proc_args(SYSCTL_HANDLER_ARGS)
658 {
659 	int *name = (int*) arg1;
660 	u_int namelen = arg2;
661 	struct proc *p;
662 	struct pargs *pa;
663 	int error = 0;
664 
665 	if (namelen != 1)
666 		return (EINVAL);
667 
668 	p = pfind((pid_t)name[0]);
669 	if (!p)
670 		return (0);
671 
672 	if ((!ps_argsopen) && p_can(curproc, p, P_CAN_SEE, NULL))
673 		return (0);
674 
675 	if (req->newptr && curproc != p)
676 		return (EPERM);
677 
678 	if (req->oldptr && p->p_args != NULL)
679 		error = SYSCTL_OUT(req, p->p_args->ar_args, p->p_args->ar_length);
680 	if (req->newptr == NULL)
681 		return (error);
682 
683 	if (p->p_args && --p->p_args->ar_ref == 0)
684 		FREE(p->p_args, M_PARGS);
685 	PROC_LOCK(p);
686 	p->p_args = NULL;
687 	PROC_UNLOCK(p);
688 
689 	if (req->newlen + sizeof(struct pargs) > ps_arg_cache_limit)
690 		return (error);
691 
692 	MALLOC(pa, struct pargs *, sizeof(struct pargs) + req->newlen,
693 	    M_PARGS, M_WAITOK);
694 	pa->ar_ref = 1;
695 	pa->ar_length = req->newlen;
696 	error = SYSCTL_IN(req, pa->ar_args, req->newlen);
697 	if (!error) {
698 		PROC_LOCK(p);
699 		p->p_args = pa;
700 		PROC_UNLOCK(p);
701 	} else
702 		FREE(pa, M_PARGS);
703 	return (error);
704 }
705 
706 SYSCTL_NODE(_kern, KERN_PROC, proc, CTLFLAG_RD,  0, "Process table");
707 
708 SYSCTL_PROC(_kern_proc, KERN_PROC_ALL, all, CTLFLAG_RD|CTLTYPE_STRUCT,
709 	0, 0, sysctl_kern_proc, "S,proc", "Return entire process table");
710 
711 SYSCTL_NODE(_kern_proc, KERN_PROC_PGRP, pgrp, CTLFLAG_RD,
712 	sysctl_kern_proc, "Process table");
713 
714 SYSCTL_NODE(_kern_proc, KERN_PROC_TTY, tty, CTLFLAG_RD,
715 	sysctl_kern_proc, "Process table");
716 
717 SYSCTL_NODE(_kern_proc, KERN_PROC_UID, uid, CTLFLAG_RD,
718 	sysctl_kern_proc, "Process table");
719 
720 SYSCTL_NODE(_kern_proc, KERN_PROC_RUID, ruid, CTLFLAG_RD,
721 	sysctl_kern_proc, "Process table");
722 
723 SYSCTL_NODE(_kern_proc, KERN_PROC_PID, pid, CTLFLAG_RD,
724 	sysctl_kern_proc, "Process table");
725 
726 SYSCTL_NODE(_kern_proc, KERN_PROC_ARGS, args, CTLFLAG_RW | CTLFLAG_ANYBODY,
727 	sysctl_kern_proc_args, "Process argument list");
728