xref: /netbsd-src/sys/kern/kern_proc.c (revision 5c46dd73a9bcb28b2994504ea090f64066b17a77)
1 /*	$NetBSD: kern_proc.c,v 1.166 2010/06/10 20:54:53 pooka Exp $	*/
2 
3 /*-
4  * Copyright (c) 1999, 2006, 2007, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center, and by Andrew Doran.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /*
34  * Copyright (c) 1982, 1986, 1989, 1991, 1993
35  *	The Regents of the University of California.  All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  * 3. Neither the name of the University nor the names of its contributors
46  *    may be used to endorse or promote products derived from this software
47  *    without specific prior written permission.
48  *
49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59  * SUCH DAMAGE.
60  *
61  *	@(#)kern_proc.c	8.7 (Berkeley) 2/14/95
62  */
63 
64 #include <sys/cdefs.h>
65 __KERNEL_RCSID(0, "$NetBSD: kern_proc.c,v 1.166 2010/06/10 20:54:53 pooka Exp $");
66 
67 #ifdef _KERNEL_OPT
68 #include "opt_kstack.h"
69 #include "opt_maxuprc.h"
70 #include "opt_dtrace.h"
71 #endif
72 
73 #include <sys/param.h>
74 #include <sys/systm.h>
75 #include <sys/kernel.h>
76 #include <sys/proc.h>
77 #include <sys/resourcevar.h>
78 #include <sys/buf.h>
79 #include <sys/acct.h>
80 #include <sys/wait.h>
81 #include <sys/file.h>
82 #include <ufs/ufs/quota.h>
83 #include <sys/uio.h>
84 #include <sys/pool.h>
85 #include <sys/pset.h>
86 #include <sys/mbuf.h>
87 #include <sys/ioctl.h>
88 #include <sys/tty.h>
89 #include <sys/signalvar.h>
90 #include <sys/ras.h>
91 #include <sys/sa.h>
92 #include <sys/savar.h>
93 #include <sys/filedesc.h>
94 #include "sys/syscall_stats.h"
95 #include <sys/kauth.h>
96 #include <sys/sleepq.h>
97 #include <sys/atomic.h>
98 #include <sys/kmem.h>
99 #include <sys/dtrace_bsd.h>
100 
101 #include <uvm/uvm.h>
102 #include <uvm/uvm_extern.h>
103 
104 /*
105  * Other process lists
106  */
107 
108 struct proclist allproc;
109 struct proclist zombproc;	/* resources have been freed */
110 
111 kmutex_t	*proc_lock;
112 
113 /*
114  * pid to proc lookup is done by indexing the pid_table array.
115  * Since pid numbers are only allocated when an empty slot
116  * has been found, there is no need to search any lists ever.
117  * (an orphaned pgrp will lock the slot, a session will lock
118  * the pgrp with the same number.)
119  * If the table is too small it is reallocated with twice the
120  * previous size and the entries 'unzipped' into the two halves.
121  * A linked list of free entries is passed through the pt_proc
122  * field of 'free' items - set odd to be an invalid ptr.
123  */
124 
125 struct pid_table {
126 	struct proc	*pt_proc;
127 	struct pgrp	*pt_pgrp;
128 };
129 #if 1	/* strongly typed cast - should be a noop */
130 static inline uint p2u(struct proc *p) { return (uint)(uintptr_t)p; }
131 #else
132 #define p2u(p) ((uint)p)
133 #endif
134 #define P_VALID(p) (!(p2u(p) & 1))
135 #define P_NEXT(p) (p2u(p) >> 1)
136 #define P_FREE(pid) ((struct proc *)(uintptr_t)((pid) << 1 | 1))
137 
138 #define INITIAL_PID_TABLE_SIZE	(1 << 5)
139 static struct pid_table *pid_table;
140 static uint pid_tbl_mask = INITIAL_PID_TABLE_SIZE - 1;
141 static uint pid_alloc_lim;	/* max we allocate before growing table */
142 static uint pid_alloc_cnt;	/* number of allocated pids */
143 
144 /* links through free slots - never empty! */
145 static uint next_free_pt, last_free_pt;
146 static pid_t pid_max = PID_MAX;		/* largest value we allocate */
147 
148 /* Components of the first process -- never freed. */
149 
150 extern struct emul emul_netbsd;	/* defined in kern_exec.c */
151 
152 struct session session0 = {
153 	.s_count = 1,
154 	.s_sid = 0,
155 };
156 struct pgrp pgrp0 = {
157 	.pg_members = LIST_HEAD_INITIALIZER(&pgrp0.pg_members),
158 	.pg_session = &session0,
159 };
160 filedesc_t filedesc0;
161 struct cwdinfo cwdi0 = {
162 	.cwdi_cmask = CMASK,		/* see cmask below */
163 	.cwdi_refcnt = 1,
164 };
165 struct plimit limit0;
166 struct pstats pstat0;
167 struct vmspace vmspace0;
168 struct sigacts sigacts0;
169 struct proc proc0 = {
170 	.p_lwps = LIST_HEAD_INITIALIZER(&proc0.p_lwps),
171 	.p_sigwaiters = LIST_HEAD_INITIALIZER(&proc0.p_sigwaiters),
172 	.p_nlwps = 1,
173 	.p_nrlwps = 1,
174 	.p_nlwpid = 1,		/* must match lwp0.l_lid */
175 	.p_pgrp = &pgrp0,
176 	.p_comm = "system",
177 	/*
178 	 * Set P_NOCLDWAIT so that kernel threads are reparented to init(8)
179 	 * when they exit.  init(8) can easily wait them out for us.
180 	 */
181 	.p_flag = PK_SYSTEM | PK_NOCLDWAIT,
182 	.p_stat = SACTIVE,
183 	.p_nice = NZERO,
184 	.p_emul = &emul_netbsd,
185 	.p_cwdi = &cwdi0,
186 	.p_limit = &limit0,
187 	.p_fd = &filedesc0,
188 	.p_vmspace = &vmspace0,
189 	.p_stats = &pstat0,
190 	.p_sigacts = &sigacts0,
191 };
192 kauth_cred_t cred0;
193 
194 int nofile = NOFILE;
195 int maxuprc = MAXUPRC;
196 int cmask = CMASK;
197 
198 MALLOC_DEFINE(M_EMULDATA, "emuldata", "Per-process emulation data");
199 MALLOC_DEFINE(M_SUBPROC, "subproc", "Proc sub-structures");
200 
201 /*
202  * The process list descriptors, used during pid allocation and
203  * by sysctl.  No locking on this data structure is needed since
204  * it is completely static.
205  */
206 const struct proclist_desc proclists[] = {
207 	{ &allproc	},
208 	{ &zombproc	},
209 	{ NULL		},
210 };
211 
212 static struct pgrp *	pg_remove(pid_t);
213 static void		pg_delete(pid_t);
214 static void		orphanpg(struct pgrp *);
215 
216 static specificdata_domain_t proc_specificdata_domain;
217 
218 static pool_cache_t proc_cache;
219 
220 static kauth_listener_t proc_listener;
221 
222 static int
223 proc_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
224     void *arg0, void *arg1, void *arg2, void *arg3)
225 {
226 	struct proc *p;
227 	int result;
228 
229 	result = KAUTH_RESULT_DEFER;
230 	p = arg0;
231 
232 	switch (action) {
233 	case KAUTH_PROCESS_CANSEE: {
234 		enum kauth_process_req req;
235 
236 		req = (enum kauth_process_req)arg1;
237 
238 		switch (req) {
239 		case KAUTH_REQ_PROCESS_CANSEE_ARGS:
240 		case KAUTH_REQ_PROCESS_CANSEE_ENTRY:
241 		case KAUTH_REQ_PROCESS_CANSEE_OPENFILES:
242 			result = KAUTH_RESULT_ALLOW;
243 
244 			break;
245 
246 		case KAUTH_REQ_PROCESS_CANSEE_ENV:
247 			if (kauth_cred_getuid(cred) !=
248 			    kauth_cred_getuid(p->p_cred) ||
249 			    kauth_cred_getuid(cred) !=
250 			    kauth_cred_getsvuid(p->p_cred))
251 				break;
252 
253 			result = KAUTH_RESULT_ALLOW;
254 
255 			break;
256 
257 		default:
258 			break;
259 		}
260 
261 		break;
262 		}
263 
264 	case KAUTH_PROCESS_FORK: {
265 		int lnprocs = (int)(unsigned long)arg2;
266 
267 		/*
268 		 * Don't allow a nonprivileged user to use the last few
269 		 * processes. The variable lnprocs is the current number of
270 		 * processes, maxproc is the limit.
271 		 */
272 		if (__predict_false((lnprocs >= maxproc - 5)))
273 			break;
274 
275 		result = KAUTH_RESULT_ALLOW;
276 
277 		break;
278 		}
279 
280 	case KAUTH_PROCESS_CORENAME:
281 	case KAUTH_PROCESS_STOPFLAG:
282 		if (proc_uidmatch(cred, p->p_cred) == 0)
283 			result = KAUTH_RESULT_ALLOW;
284 
285 		break;
286 
287 	default:
288 		break;
289 	}
290 
291 	return result;
292 }
293 
294 /*
295  * Initialize global process hashing structures.
296  */
297 void
298 procinit(void)
299 {
300 	const struct proclist_desc *pd;
301 	u_int i;
302 #define	LINK_EMPTY ((PID_MAX + INITIAL_PID_TABLE_SIZE) & ~(INITIAL_PID_TABLE_SIZE - 1))
303 
304 	for (pd = proclists; pd->pd_list != NULL; pd++)
305 		LIST_INIT(pd->pd_list);
306 
307 	proc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
308 	pid_table = kmem_alloc(INITIAL_PID_TABLE_SIZE
309 	    * sizeof(struct pid_table), KM_SLEEP);
310 
311 	/* Set free list running through table...
312 	   Preset 'use count' above PID_MAX so we allocate pid 1 next. */
313 	for (i = 0; i <= pid_tbl_mask; i++) {
314 		pid_table[i].pt_proc = P_FREE(LINK_EMPTY + i + 1);
315 		pid_table[i].pt_pgrp = 0;
316 	}
317 	/* slot 0 is just grabbed */
318 	next_free_pt = 1;
319 	/* Need to fix last entry. */
320 	last_free_pt = pid_tbl_mask;
321 	pid_table[last_free_pt].pt_proc = P_FREE(LINK_EMPTY);
322 	/* point at which we grow table - to avoid reusing pids too often */
323 	pid_alloc_lim = pid_tbl_mask - 1;
324 #undef LINK_EMPTY
325 
326 	proc_specificdata_domain = specificdata_domain_create();
327 	KASSERT(proc_specificdata_domain != NULL);
328 
329 	proc_cache = pool_cache_init(sizeof(struct proc), 0, 0, 0,
330 	    "procpl", NULL, IPL_NONE, NULL, NULL, NULL);
331 
332 	proc_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS,
333 	    proc_listener_cb, NULL);
334 }
335 
336 /*
337  * Initialize process 0.
338  */
339 void
340 proc0_init(void)
341 {
342 	struct proc *p;
343 	struct pgrp *pg;
344 	rlim_t lim;
345 	int i;
346 
347 	p = &proc0;
348 	pg = &pgrp0;
349 
350 	mutex_init(&p->p_stmutex, MUTEX_DEFAULT, IPL_HIGH);
351 	mutex_init(&p->p_auxlock, MUTEX_DEFAULT, IPL_NONE);
352 	p->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
353 
354 	rw_init(&p->p_reflock);
355 	cv_init(&p->p_waitcv, "wait");
356 	cv_init(&p->p_lwpcv, "lwpwait");
357 
358 	LIST_INSERT_HEAD(&p->p_lwps, &lwp0, l_sibling);
359 
360 	pid_table[0].pt_proc = p;
361 	LIST_INSERT_HEAD(&allproc, p, p_list);
362 
363 	pid_table[0].pt_pgrp = pg;
364 	LIST_INSERT_HEAD(&pg->pg_members, p, p_pglist);
365 
366 #ifdef __HAVE_SYSCALL_INTERN
367 	(*p->p_emul->e_syscall_intern)(p);
368 #endif
369 
370 	/* Create credentials. */
371 	cred0 = kauth_cred_alloc();
372 	p->p_cred = cred0;
373 
374 	/* Create the CWD info. */
375 	rw_init(&cwdi0.cwdi_lock);
376 
377 	/* Create the limits structures. */
378 	mutex_init(&limit0.pl_lock, MUTEX_DEFAULT, IPL_NONE);
379 	for (i = 0; i < __arraycount(limit0.pl_rlimit); i++)
380 		limit0.pl_rlimit[i].rlim_cur =
381 		    limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
382 
383 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
384 	limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
385 	    maxfiles < nofile ? maxfiles : nofile;
386 
387 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
388 	limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
389 	    maxproc < maxuprc ? maxproc : maxuprc;
390 
391 	lim = MIN(VM_MAXUSER_ADDRESS, ctob((rlim_t)uvmexp.free));
392 	limit0.pl_rlimit[RLIMIT_RSS].rlim_max = lim;
393 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = lim;
394 	limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = lim / 3;
395 	limit0.pl_corename = defcorename;
396 	limit0.pl_refcnt = 1;
397 	limit0.pl_sv_limit = NULL;
398 
399 	/* Configure virtual memory system, set vm rlimits. */
400 	uvm_init_limits(p);
401 
402 	/* Initialize file descriptor table for proc0. */
403 	fd_init(&filedesc0);
404 
405 	/*
406 	 * Initialize proc0's vmspace, which uses the kernel pmap.
407 	 * All kernel processes (which never have user space mappings)
408 	 * share proc0's vmspace, and thus, the kernel pmap.
409 	 */
410 	uvmspace_init(&vmspace0, pmap_kernel(), round_page(VM_MIN_ADDRESS),
411 	    trunc_page(VM_MAX_ADDRESS));
412 
413 	/* Initialize signal state for proc0. XXX IPL_SCHED */
414 	mutex_init(&p->p_sigacts->sa_mutex, MUTEX_DEFAULT, IPL_SCHED);
415 	siginit(p);
416 
417 	proc_initspecific(p);
418 	kdtrace_proc_ctor(NULL, p);
419 }
420 
421 /*
422  * Session reference counting.
423  */
424 
425 void
426 proc_sesshold(struct session *ss)
427 {
428 
429 	KASSERT(mutex_owned(proc_lock));
430 	ss->s_count++;
431 }
432 
433 void
434 proc_sessrele(struct session *ss)
435 {
436 
437 	KASSERT(mutex_owned(proc_lock));
438 	/*
439 	 * We keep the pgrp with the same id as the session in order to
440 	 * stop a process being given the same pid.  Since the pgrp holds
441 	 * a reference to the session, it must be a 'zombie' pgrp by now.
442 	 */
443 	if (--ss->s_count == 0) {
444 		struct pgrp *pg;
445 
446 		pg = pg_remove(ss->s_sid);
447 		mutex_exit(proc_lock);
448 
449 		kmem_free(pg, sizeof(struct pgrp));
450 		kmem_free(ss, sizeof(struct session));
451 	} else {
452 		mutex_exit(proc_lock);
453 	}
454 }
455 
456 /*
457  * Check that the specified process group is in the session of the
458  * specified process.
459  * Treats -ve ids as process ids.
460  * Used to validate TIOCSPGRP requests.
461  */
462 int
463 pgid_in_session(struct proc *p, pid_t pg_id)
464 {
465 	struct pgrp *pgrp;
466 	struct session *session;
467 	int error;
468 
469 	mutex_enter(proc_lock);
470 	if (pg_id < 0) {
471 		struct proc *p1 = p_find(-pg_id, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
472 		if (p1 == NULL)
473 			return EINVAL;
474 		pgrp = p1->p_pgrp;
475 	} else {
476 		pgrp = pg_find(pg_id, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
477 		if (pgrp == NULL)
478 			return EINVAL;
479 	}
480 	session = pgrp->pg_session;
481 	if (session != p->p_pgrp->pg_session)
482 		error = EPERM;
483 	else
484 		error = 0;
485 	mutex_exit(proc_lock);
486 
487 	return error;
488 }
489 
490 /*
491  * p_inferior: is p an inferior of q?
492  */
493 static inline bool
494 p_inferior(struct proc *p, struct proc *q)
495 {
496 
497 	KASSERT(mutex_owned(proc_lock));
498 
499 	for (; p != q; p = p->p_pptr)
500 		if (p->p_pid == 0)
501 			return false;
502 	return true;
503 }
504 
505 /*
506  * Locate a process by number
507  */
508 struct proc *
509 p_find(pid_t pid, uint flags)
510 {
511 	struct proc *p;
512 	char stat;
513 
514 	if (!(flags & PFIND_LOCKED))
515 		mutex_enter(proc_lock);
516 
517 	p = pid_table[pid & pid_tbl_mask].pt_proc;
518 
519 	/* Only allow live processes to be found by pid. */
520 	/* XXXSMP p_stat */
521 	if (P_VALID(p) && p->p_pid == pid && ((stat = p->p_stat) == SACTIVE ||
522 	    stat == SSTOP || ((flags & PFIND_ZOMBIE) &&
523 	    (stat == SZOMB || stat == SDEAD || stat == SDYING)))) {
524 		if (flags & PFIND_UNLOCK_OK)
525 			 mutex_exit(proc_lock);
526 		return p;
527 	}
528 	if (flags & PFIND_UNLOCK_FAIL)
529 		mutex_exit(proc_lock);
530 	return NULL;
531 }
532 
533 
534 /*
535  * Locate a process group by number
536  */
537 struct pgrp *
538 pg_find(pid_t pgid, uint flags)
539 {
540 	struct pgrp *pg;
541 
542 	if (!(flags & PFIND_LOCKED))
543 		mutex_enter(proc_lock);
544 	pg = pid_table[pgid & pid_tbl_mask].pt_pgrp;
545 	/*
546 	 * Can't look up a pgrp that only exists because the session
547 	 * hasn't died yet (traditional)
548 	 */
549 	if (pg == NULL || pg->pg_id != pgid || LIST_EMPTY(&pg->pg_members)) {
550 		if (flags & PFIND_UNLOCK_FAIL)
551 			 mutex_exit(proc_lock);
552 		return NULL;
553 	}
554 
555 	if (flags & PFIND_UNLOCK_OK)
556 		mutex_exit(proc_lock);
557 	return pg;
558 }
559 
560 static void
561 expand_pid_table(void)
562 {
563 	size_t pt_size, tsz;
564 	struct pid_table *n_pt, *new_pt;
565 	struct proc *proc;
566 	struct pgrp *pgrp;
567 	pid_t pid;
568 	u_int i;
569 
570 	pt_size = pid_tbl_mask + 1;
571 	tsz = pt_size * 2 * sizeof(struct pid_table);
572 	new_pt = kmem_alloc(tsz, KM_SLEEP);
573 
574 	mutex_enter(proc_lock);
575 	if (pt_size != pid_tbl_mask + 1) {
576 		/* Another process beat us to it... */
577 		mutex_exit(proc_lock);
578 		kmem_free(new_pt, tsz);
579 		return;
580 	}
581 
582 	/*
583 	 * Copy entries from old table into new one.
584 	 * If 'pid' is 'odd' we need to place in the upper half,
585 	 * even pid's to the lower half.
586 	 * Free items stay in the low half so we don't have to
587 	 * fixup the reference to them.
588 	 * We stuff free items on the front of the freelist
589 	 * because we can't write to unmodified entries.
590 	 * Processing the table backwards maintains a semblance
591 	 * of issueing pid numbers that increase with time.
592 	 */
593 	i = pt_size - 1;
594 	n_pt = new_pt + i;
595 	for (; ; i--, n_pt--) {
596 		proc = pid_table[i].pt_proc;
597 		pgrp = pid_table[i].pt_pgrp;
598 		if (!P_VALID(proc)) {
599 			/* Up 'use count' so that link is valid */
600 			pid = (P_NEXT(proc) + pt_size) & ~pt_size;
601 			proc = P_FREE(pid);
602 			if (pgrp)
603 				pid = pgrp->pg_id;
604 		} else
605 			pid = proc->p_pid;
606 
607 		/* Save entry in appropriate half of table */
608 		n_pt[pid & pt_size].pt_proc = proc;
609 		n_pt[pid & pt_size].pt_pgrp = pgrp;
610 
611 		/* Put other piece on start of free list */
612 		pid = (pid ^ pt_size) & ~pid_tbl_mask;
613 		n_pt[pid & pt_size].pt_proc =
614 				    P_FREE((pid & ~pt_size) | next_free_pt);
615 		n_pt[pid & pt_size].pt_pgrp = 0;
616 		next_free_pt = i | (pid & pt_size);
617 		if (i == 0)
618 			break;
619 	}
620 
621 	/* Save old table size and switch tables */
622 	tsz = pt_size * sizeof(struct pid_table);
623 	n_pt = pid_table;
624 	pid_table = new_pt;
625 	pid_tbl_mask = pt_size * 2 - 1;
626 
627 	/*
628 	 * pid_max starts as PID_MAX (= 30000), once we have 16384
629 	 * allocated pids we need it to be larger!
630 	 */
631 	if (pid_tbl_mask > PID_MAX) {
632 		pid_max = pid_tbl_mask * 2 + 1;
633 		pid_alloc_lim |= pid_alloc_lim << 1;
634 	} else
635 		pid_alloc_lim <<= 1;	/* doubles number of free slots... */
636 
637 	mutex_exit(proc_lock);
638 	kmem_free(n_pt, tsz);
639 }
640 
641 struct proc *
642 proc_alloc(void)
643 {
644 	struct proc *p;
645 	int nxt;
646 	pid_t pid;
647 	struct pid_table *pt;
648 
649 	p = pool_cache_get(proc_cache, PR_WAITOK);
650 	p->p_stat = SIDL;			/* protect against others */
651 
652 	proc_initspecific(p);
653 	kdtrace_proc_ctor(NULL, p);
654 
655 	for (;;expand_pid_table()) {
656 		if (__predict_false(pid_alloc_cnt >= pid_alloc_lim))
657 			/* ensure pids cycle through 2000+ values */
658 			continue;
659 		mutex_enter(proc_lock);
660 		pt = &pid_table[next_free_pt];
661 #ifdef DIAGNOSTIC
662 		if (__predict_false(P_VALID(pt->pt_proc) || pt->pt_pgrp))
663 			panic("proc_alloc: slot busy");
664 #endif
665 		nxt = P_NEXT(pt->pt_proc);
666 		if (nxt & pid_tbl_mask)
667 			break;
668 		/* Table full - expand (NB last entry not used....) */
669 		mutex_exit(proc_lock);
670 	}
671 
672 	/* pid is 'saved use count' + 'size' + entry */
673 	pid = (nxt & ~pid_tbl_mask) + pid_tbl_mask + 1 + next_free_pt;
674 	if ((uint)pid > (uint)pid_max)
675 		pid &= pid_tbl_mask;
676 	p->p_pid = pid;
677 	next_free_pt = nxt & pid_tbl_mask;
678 
679 	/* Grab table slot */
680 	pt->pt_proc = p;
681 	pid_alloc_cnt++;
682 	mutex_exit(proc_lock);
683 
684 	return p;
685 }
686 
687 /*
688  * Free a process id - called from proc_free (in kern_exit.c)
689  *
690  * Called with the proc_lock held.
691  */
692 void
693 proc_free_pid(struct proc *p)
694 {
695 	pid_t pid = p->p_pid;
696 	struct pid_table *pt;
697 
698 	KASSERT(mutex_owned(proc_lock));
699 
700 	pt = &pid_table[pid & pid_tbl_mask];
701 #ifdef DIAGNOSTIC
702 	if (__predict_false(pt->pt_proc != p))
703 		panic("proc_free: pid_table mismatch, pid %x, proc %p",
704 			pid, p);
705 #endif
706 	/* save pid use count in slot */
707 	pt->pt_proc = P_FREE(pid & ~pid_tbl_mask);
708 
709 	if (pt->pt_pgrp == NULL) {
710 		/* link last freed entry onto ours */
711 		pid &= pid_tbl_mask;
712 		pt = &pid_table[last_free_pt];
713 		pt->pt_proc = P_FREE(P_NEXT(pt->pt_proc) | pid);
714 		last_free_pt = pid;
715 		pid_alloc_cnt--;
716 	}
717 
718 	atomic_dec_uint(&nprocs);
719 }
720 
721 void
722 proc_free_mem(struct proc *p)
723 {
724 
725 	kdtrace_proc_dtor(NULL, p);
726 	pool_cache_put(proc_cache, p);
727 }
728 
729 /*
730  * proc_enterpgrp: move p to a new or existing process group (and session).
731  *
732  * If we are creating a new pgrp, the pgid should equal
733  * the calling process' pid.
734  * If is only valid to enter a process group that is in the session
735  * of the process.
736  * Also mksess should only be set if we are creating a process group
737  *
738  * Only called from sys_setsid and sys_setpgid.
739  */
740 int
741 proc_enterpgrp(struct proc *curp, pid_t pid, pid_t pgid, bool mksess)
742 {
743 	struct pgrp *new_pgrp, *pgrp;
744 	struct session *sess;
745 	struct proc *p;
746 	int rval;
747 	pid_t pg_id = NO_PGID;
748 
749 	sess = mksess ? kmem_alloc(sizeof(*sess), KM_SLEEP) : NULL;
750 
751 	/* Allocate data areas we might need before doing any validity checks */
752 	mutex_enter(proc_lock);		/* Because pid_table might change */
753 	if (pid_table[pgid & pid_tbl_mask].pt_pgrp == 0) {
754 		mutex_exit(proc_lock);
755 		new_pgrp = kmem_alloc(sizeof(*new_pgrp), KM_SLEEP);
756 		mutex_enter(proc_lock);
757 	} else
758 		new_pgrp = NULL;
759 	rval = EPERM;	/* most common error (to save typing) */
760 
761 	/* Check pgrp exists or can be created */
762 	pgrp = pid_table[pgid & pid_tbl_mask].pt_pgrp;
763 	if (pgrp != NULL && pgrp->pg_id != pgid)
764 		goto done;
765 
766 	/* Can only set another process under restricted circumstances. */
767 	if (pid != curp->p_pid) {
768 		/* must exist and be one of our children... */
769 		if ((p = p_find(pid, PFIND_LOCKED)) == NULL ||
770 		    !p_inferior(p, curp)) {
771 			rval = ESRCH;
772 			goto done;
773 		}
774 		/* ... in the same session... */
775 		if (sess != NULL || p->p_session != curp->p_session)
776 			goto done;
777 		/* ... existing pgid must be in same session ... */
778 		if (pgrp != NULL && pgrp->pg_session != p->p_session)
779 			goto done;
780 		/* ... and not done an exec. */
781 		if (p->p_flag & PK_EXEC) {
782 			rval = EACCES;
783 			goto done;
784 		}
785 	} else {
786 		/* ... setsid() cannot re-enter a pgrp */
787 		if (mksess && (curp->p_pgid == curp->p_pid ||
788 		    pg_find(curp->p_pid, PFIND_LOCKED)))
789 			goto done;
790 		p = curp;
791 	}
792 
793 	/* Changing the process group/session of a session
794 	   leader is definitely off limits. */
795 	if (SESS_LEADER(p)) {
796 		if (sess == NULL && p->p_pgrp == pgrp)
797 			/* unless it's a definite noop */
798 			rval = 0;
799 		goto done;
800 	}
801 
802 	/* Can only create a process group with id of process */
803 	if (pgrp == NULL && pgid != pid)
804 		goto done;
805 
806 	/* Can only create a session if creating pgrp */
807 	if (sess != NULL && pgrp != NULL)
808 		goto done;
809 
810 	/* Check we allocated memory for a pgrp... */
811 	if (pgrp == NULL && new_pgrp == NULL)
812 		goto done;
813 
814 	/* Don't attach to 'zombie' pgrp */
815 	if (pgrp != NULL && LIST_EMPTY(&pgrp->pg_members))
816 		goto done;
817 
818 	/* Expect to succeed now */
819 	rval = 0;
820 
821 	if (pgrp == p->p_pgrp)
822 		/* nothing to do */
823 		goto done;
824 
825 	/* Ok all setup, link up required structures */
826 
827 	if (pgrp == NULL) {
828 		pgrp = new_pgrp;
829 		new_pgrp = NULL;
830 		if (sess != NULL) {
831 			sess->s_sid = p->p_pid;
832 			sess->s_leader = p;
833 			sess->s_count = 1;
834 			sess->s_ttyvp = NULL;
835 			sess->s_ttyp = NULL;
836 			sess->s_flags = p->p_session->s_flags & ~S_LOGIN_SET;
837 			memcpy(sess->s_login, p->p_session->s_login,
838 			    sizeof(sess->s_login));
839 			p->p_lflag &= ~PL_CONTROLT;
840 		} else {
841 			sess = p->p_pgrp->pg_session;
842 			proc_sesshold(sess);
843 		}
844 		pgrp->pg_session = sess;
845 		sess = NULL;
846 
847 		pgrp->pg_id = pgid;
848 		LIST_INIT(&pgrp->pg_members);
849 #ifdef DIAGNOSTIC
850 		if (__predict_false(pid_table[pgid & pid_tbl_mask].pt_pgrp))
851 			panic("enterpgrp: pgrp table slot in use");
852 		if (__predict_false(mksess && p != curp))
853 			panic("enterpgrp: mksession and p != curproc");
854 #endif
855 		pid_table[pgid & pid_tbl_mask].pt_pgrp = pgrp;
856 		pgrp->pg_jobc = 0;
857 	}
858 
859 	/*
860 	 * Adjust eligibility of affected pgrps to participate in job control.
861 	 * Increment eligibility counts before decrementing, otherwise we
862 	 * could reach 0 spuriously during the first call.
863 	 */
864 	fixjobc(p, pgrp, 1);
865 	fixjobc(p, p->p_pgrp, 0);
866 
867 	/* Interlock with ttread(). */
868 	mutex_spin_enter(&tty_lock);
869 
870 	/* Move process to requested group. */
871 	LIST_REMOVE(p, p_pglist);
872 	if (LIST_EMPTY(&p->p_pgrp->pg_members))
873 		/* defer delete until we've dumped the lock */
874 		pg_id = p->p_pgrp->pg_id;
875 	p->p_pgrp = pgrp;
876 	LIST_INSERT_HEAD(&pgrp->pg_members, p, p_pglist);
877 
878 	/* Done with the swap; we can release the tty mutex. */
879 	mutex_spin_exit(&tty_lock);
880 
881     done:
882 	if (pg_id != NO_PGID) {
883 		/* Releases proc_lock. */
884 		pg_delete(pg_id);
885 	} else {
886 		mutex_exit(proc_lock);
887 	}
888 	if (sess != NULL)
889 		kmem_free(sess, sizeof(*sess));
890 	if (new_pgrp != NULL)
891 		kmem_free(new_pgrp, sizeof(*new_pgrp));
892 #ifdef DEBUG_PGRP
893 	if (__predict_false(rval))
894 		printf("enterpgrp(%d,%d,%d), curproc %d, rval %d\n",
895 			pid, pgid, mksess, curp->p_pid, rval);
896 #endif
897 	return rval;
898 }
899 
900 /*
901  * proc_leavepgrp: remove a process from its process group.
902  *  => must be called with the proc_lock held, which will be released;
903  */
904 void
905 proc_leavepgrp(struct proc *p)
906 {
907 	struct pgrp *pgrp;
908 
909 	KASSERT(mutex_owned(proc_lock));
910 
911 	/* Interlock with ttread() */
912 	mutex_spin_enter(&tty_lock);
913 	pgrp = p->p_pgrp;
914 	LIST_REMOVE(p, p_pglist);
915 	p->p_pgrp = NULL;
916 	mutex_spin_exit(&tty_lock);
917 
918 	if (LIST_EMPTY(&pgrp->pg_members)) {
919 		/* Releases proc_lock. */
920 		pg_delete(pgrp->pg_id);
921 	} else {
922 		mutex_exit(proc_lock);
923 	}
924 }
925 
926 /*
927  * pg_remove: remove a process group from the table.
928  *  => must be called with the proc_lock held;
929  *  => returns process group to free;
930  */
931 static struct pgrp *
932 pg_remove(pid_t pg_id)
933 {
934 	struct pgrp *pgrp;
935 	struct pid_table *pt;
936 
937 	KASSERT(mutex_owned(proc_lock));
938 
939 	pt = &pid_table[pg_id & pid_tbl_mask];
940 	pgrp = pt->pt_pgrp;
941 
942 	KASSERT(pgrp != NULL);
943 	KASSERT(pgrp->pg_id == pg_id);
944 	KASSERT(LIST_EMPTY(&pgrp->pg_members));
945 
946 	pt->pt_pgrp = NULL;
947 
948 	if (!P_VALID(pt->pt_proc)) {
949 		/* Orphaned pgrp, put slot onto free list. */
950 		KASSERT((P_NEXT(pt->pt_proc) & pid_tbl_mask) == 0);
951 		pg_id &= pid_tbl_mask;
952 		pt = &pid_table[last_free_pt];
953 		pt->pt_proc = P_FREE(P_NEXT(pt->pt_proc) | pg_id);
954 		last_free_pt = pg_id;
955 		pid_alloc_cnt--;
956 	}
957 	return pgrp;
958 }
959 
960 /*
961  * pg_delete: delete and free a process group.
962  *  => must be called with the proc_lock held, which will be released.
963  */
964 static void
965 pg_delete(pid_t pg_id)
966 {
967 	struct pgrp *pg;
968 	struct tty *ttyp;
969 	struct session *ss;
970 
971 	KASSERT(mutex_owned(proc_lock));
972 
973 	pg = pid_table[pg_id & pid_tbl_mask].pt_pgrp;
974 	if (pg == NULL || pg->pg_id != pg_id || !LIST_EMPTY(&pg->pg_members)) {
975 		mutex_exit(proc_lock);
976 		return;
977 	}
978 
979 	ss = pg->pg_session;
980 
981 	/* Remove reference (if any) from tty to this process group */
982 	mutex_spin_enter(&tty_lock);
983 	ttyp = ss->s_ttyp;
984 	if (ttyp != NULL && ttyp->t_pgrp == pg) {
985 		ttyp->t_pgrp = NULL;
986 		KASSERT(ttyp->t_session == ss);
987 	}
988 	mutex_spin_exit(&tty_lock);
989 
990 	/*
991 	 * The leading process group in a session is freed by proc_sessrele(),
992 	 * if last reference.  Note: proc_sessrele() releases proc_lock.
993 	 */
994 	pg = (ss->s_sid != pg->pg_id) ? pg_remove(pg_id) : NULL;
995 	proc_sessrele(ss);
996 
997 	if (pg != NULL) {
998 		/* Free it, if was not done by proc_sessrele(). */
999 		kmem_free(pg, sizeof(struct pgrp));
1000 	}
1001 }
1002 
1003 /*
1004  * Adjust pgrp jobc counters when specified process changes process group.
1005  * We count the number of processes in each process group that "qualify"
1006  * the group for terminal job control (those with a parent in a different
1007  * process group of the same session).  If that count reaches zero, the
1008  * process group becomes orphaned.  Check both the specified process'
1009  * process group and that of its children.
1010  * entering == 0 => p is leaving specified group.
1011  * entering == 1 => p is entering specified group.
1012  *
1013  * Call with proc_lock held.
1014  */
1015 void
1016 fixjobc(struct proc *p, struct pgrp *pgrp, int entering)
1017 {
1018 	struct pgrp *hispgrp;
1019 	struct session *mysession = pgrp->pg_session;
1020 	struct proc *child;
1021 
1022 	KASSERT(mutex_owned(proc_lock));
1023 
1024 	/*
1025 	 * Check p's parent to see whether p qualifies its own process
1026 	 * group; if so, adjust count for p's process group.
1027 	 */
1028 	hispgrp = p->p_pptr->p_pgrp;
1029 	if (hispgrp != pgrp && hispgrp->pg_session == mysession) {
1030 		if (entering) {
1031 			pgrp->pg_jobc++;
1032 			p->p_lflag &= ~PL_ORPHANPG;
1033 		} else if (--pgrp->pg_jobc == 0)
1034 			orphanpg(pgrp);
1035 	}
1036 
1037 	/*
1038 	 * Check this process' children to see whether they qualify
1039 	 * their process groups; if so, adjust counts for children's
1040 	 * process groups.
1041 	 */
1042 	LIST_FOREACH(child, &p->p_children, p_sibling) {
1043 		hispgrp = child->p_pgrp;
1044 		if (hispgrp != pgrp && hispgrp->pg_session == mysession &&
1045 		    !P_ZOMBIE(child)) {
1046 			if (entering) {
1047 				child->p_lflag &= ~PL_ORPHANPG;
1048 				hispgrp->pg_jobc++;
1049 			} else if (--hispgrp->pg_jobc == 0)
1050 				orphanpg(hispgrp);
1051 		}
1052 	}
1053 }
1054 
1055 /*
1056  * A process group has become orphaned;
1057  * if there are any stopped processes in the group,
1058  * hang-up all process in that group.
1059  *
1060  * Call with proc_lock held.
1061  */
1062 static void
1063 orphanpg(struct pgrp *pg)
1064 {
1065 	struct proc *p;
1066 
1067 	KASSERT(mutex_owned(proc_lock));
1068 
1069 	LIST_FOREACH(p, &pg->pg_members, p_pglist) {
1070 		if (p->p_stat == SSTOP) {
1071 			p->p_lflag |= PL_ORPHANPG;
1072 			psignal(p, SIGHUP);
1073 			psignal(p, SIGCONT);
1074 		}
1075 	}
1076 }
1077 
1078 #ifdef DDB
1079 #include <ddb/db_output.h>
1080 void pidtbl_dump(void);
1081 void
1082 pidtbl_dump(void)
1083 {
1084 	struct pid_table *pt;
1085 	struct proc *p;
1086 	struct pgrp *pgrp;
1087 	int id;
1088 
1089 	db_printf("pid table %p size %x, next %x, last %x\n",
1090 		pid_table, pid_tbl_mask+1,
1091 		next_free_pt, last_free_pt);
1092 	for (pt = pid_table, id = 0; id <= pid_tbl_mask; id++, pt++) {
1093 		p = pt->pt_proc;
1094 		if (!P_VALID(p) && !pt->pt_pgrp)
1095 			continue;
1096 		db_printf("  id %x: ", id);
1097 		if (P_VALID(p))
1098 			db_printf("proc %p id %d (0x%x) %s\n",
1099 				p, p->p_pid, p->p_pid, p->p_comm);
1100 		else
1101 			db_printf("next %x use %x\n",
1102 				P_NEXT(p) & pid_tbl_mask,
1103 				P_NEXT(p) & ~pid_tbl_mask);
1104 		if ((pgrp = pt->pt_pgrp)) {
1105 			db_printf("\tsession %p, sid %d, count %d, login %s\n",
1106 			    pgrp->pg_session, pgrp->pg_session->s_sid,
1107 			    pgrp->pg_session->s_count,
1108 			    pgrp->pg_session->s_login);
1109 			db_printf("\tpgrp %p, pg_id %d, pg_jobc %d, members %p\n",
1110 			    pgrp, pgrp->pg_id, pgrp->pg_jobc,
1111 			    LIST_FIRST(&pgrp->pg_members));
1112 			LIST_FOREACH(p, &pgrp->pg_members, p_pglist) {
1113 				db_printf("\t\tpid %d addr %p pgrp %p %s\n",
1114 				    p->p_pid, p, p->p_pgrp, p->p_comm);
1115 			}
1116 		}
1117 	}
1118 }
1119 #endif /* DDB */
1120 
1121 #ifdef KSTACK_CHECK_MAGIC
1122 
1123 #define	KSTACK_MAGIC	0xdeadbeaf
1124 
1125 /* XXX should be per process basis? */
1126 static int	kstackleftmin = KSTACK_SIZE;
1127 static int	kstackleftthres = KSTACK_SIZE / 8;
1128 
1129 void
1130 kstack_setup_magic(const struct lwp *l)
1131 {
1132 	uint32_t *ip;
1133 	uint32_t const *end;
1134 
1135 	KASSERT(l != NULL);
1136 	KASSERT(l != &lwp0);
1137 
1138 	/*
1139 	 * fill all the stack with magic number
1140 	 * so that later modification on it can be detected.
1141 	 */
1142 	ip = (uint32_t *)KSTACK_LOWEST_ADDR(l);
1143 	end = (uint32_t *)((char *)KSTACK_LOWEST_ADDR(l) + KSTACK_SIZE);
1144 	for (; ip < end; ip++) {
1145 		*ip = KSTACK_MAGIC;
1146 	}
1147 }
1148 
1149 void
1150 kstack_check_magic(const struct lwp *l)
1151 {
1152 	uint32_t const *ip, *end;
1153 	int stackleft;
1154 
1155 	KASSERT(l != NULL);
1156 
1157 	/* don't check proc0 */ /*XXX*/
1158 	if (l == &lwp0)
1159 		return;
1160 
1161 #ifdef __MACHINE_STACK_GROWS_UP
1162 	/* stack grows upwards (eg. hppa) */
1163 	ip = (uint32_t *)((void *)KSTACK_LOWEST_ADDR(l) + KSTACK_SIZE);
1164 	end = (uint32_t *)KSTACK_LOWEST_ADDR(l);
1165 	for (ip--; ip >= end; ip--)
1166 		if (*ip != KSTACK_MAGIC)
1167 			break;
1168 
1169 	stackleft = (void *)KSTACK_LOWEST_ADDR(l) + KSTACK_SIZE - (void *)ip;
1170 #else /* __MACHINE_STACK_GROWS_UP */
1171 	/* stack grows downwards (eg. i386) */
1172 	ip = (uint32_t *)KSTACK_LOWEST_ADDR(l);
1173 	end = (uint32_t *)((char *)KSTACK_LOWEST_ADDR(l) + KSTACK_SIZE);
1174 	for (; ip < end; ip++)
1175 		if (*ip != KSTACK_MAGIC)
1176 			break;
1177 
1178 	stackleft = ((const char *)ip) - (const char *)KSTACK_LOWEST_ADDR(l);
1179 #endif /* __MACHINE_STACK_GROWS_UP */
1180 
1181 	if (kstackleftmin > stackleft) {
1182 		kstackleftmin = stackleft;
1183 		if (stackleft < kstackleftthres)
1184 			printf("warning: kernel stack left %d bytes"
1185 			    "(pid %u:lid %u)\n", stackleft,
1186 			    (u_int)l->l_proc->p_pid, (u_int)l->l_lid);
1187 	}
1188 
1189 	if (stackleft <= 0) {
1190 		panic("magic on the top of kernel stack changed for "
1191 		    "pid %u, lid %u: maybe kernel stack overflow",
1192 		    (u_int)l->l_proc->p_pid, (u_int)l->l_lid);
1193 	}
1194 }
1195 #endif /* KSTACK_CHECK_MAGIC */
1196 
1197 int
1198 proclist_foreach_call(struct proclist *list,
1199     int (*callback)(struct proc *, void *arg), void *arg)
1200 {
1201 	struct proc marker;
1202 	struct proc *p;
1203 	int ret = 0;
1204 
1205 	marker.p_flag = PK_MARKER;
1206 	mutex_enter(proc_lock);
1207 	for (p = LIST_FIRST(list); ret == 0 && p != NULL;) {
1208 		if (p->p_flag & PK_MARKER) {
1209 			p = LIST_NEXT(p, p_list);
1210 			continue;
1211 		}
1212 		LIST_INSERT_AFTER(p, &marker, p_list);
1213 		ret = (*callback)(p, arg);
1214 		KASSERT(mutex_owned(proc_lock));
1215 		p = LIST_NEXT(&marker, p_list);
1216 		LIST_REMOVE(&marker, p_list);
1217 	}
1218 	mutex_exit(proc_lock);
1219 
1220 	return ret;
1221 }
1222 
1223 int
1224 proc_vmspace_getref(struct proc *p, struct vmspace **vm)
1225 {
1226 
1227 	/* XXXCDC: how should locking work here? */
1228 
1229 	/* curproc exception is for coredump. */
1230 
1231 	if ((p != curproc && (p->p_sflag & PS_WEXIT) != 0) ||
1232 	    (p->p_vmspace->vm_refcnt < 1)) { /* XXX */
1233 		return EFAULT;
1234 	}
1235 
1236 	uvmspace_addref(p->p_vmspace);
1237 	*vm = p->p_vmspace;
1238 
1239 	return 0;
1240 }
1241 
1242 /*
1243  * Acquire a write lock on the process credential.
1244  */
1245 void
1246 proc_crmod_enter(void)
1247 {
1248 	struct lwp *l = curlwp;
1249 	struct proc *p = l->l_proc;
1250 	struct plimit *lim;
1251 	kauth_cred_t oc;
1252 	char *cn;
1253 
1254 	/* Reset what needs to be reset in plimit. */
1255 	if (p->p_limit->pl_corename != defcorename) {
1256 		lim_privatise(p, false);
1257 		lim = p->p_limit;
1258 		mutex_enter(&lim->pl_lock);
1259 		cn = lim->pl_corename;
1260 		lim->pl_corename = defcorename;
1261 		mutex_exit(&lim->pl_lock);
1262 		if (cn != defcorename)
1263 			free(cn, M_TEMP);
1264 	}
1265 
1266 	mutex_enter(p->p_lock);
1267 
1268 	/* Ensure the LWP cached credentials are up to date. */
1269 	if ((oc = l->l_cred) != p->p_cred) {
1270 		kauth_cred_hold(p->p_cred);
1271 		l->l_cred = p->p_cred;
1272 		kauth_cred_free(oc);
1273 	}
1274 
1275 }
1276 
1277 /*
1278  * Set in a new process credential, and drop the write lock.  The credential
1279  * must have a reference already.  Optionally, free a no-longer required
1280  * credential.  The scheduler also needs to inspect p_cred, so we also
1281  * briefly acquire the sched state mutex.
1282  */
1283 void
1284 proc_crmod_leave(kauth_cred_t scred, kauth_cred_t fcred, bool sugid)
1285 {
1286 	struct lwp *l = curlwp, *l2;
1287 	struct proc *p = l->l_proc;
1288 	kauth_cred_t oc;
1289 
1290 	KASSERT(mutex_owned(p->p_lock));
1291 
1292 	/* Is there a new credential to set in? */
1293 	if (scred != NULL) {
1294 		p->p_cred = scred;
1295 		LIST_FOREACH(l2, &p->p_lwps, l_sibling) {
1296 			if (l2 != l)
1297 				l2->l_prflag |= LPR_CRMOD;
1298 		}
1299 
1300 		/* Ensure the LWP cached credentials are up to date. */
1301 		if ((oc = l->l_cred) != scred) {
1302 			kauth_cred_hold(scred);
1303 			l->l_cred = scred;
1304 		}
1305 	} else
1306 		oc = NULL;	/* XXXgcc */
1307 
1308 	if (sugid) {
1309 		/*
1310 		 * Mark process as having changed credentials, stops
1311 		 * tracing etc.
1312 		 */
1313 		p->p_flag |= PK_SUGID;
1314 	}
1315 
1316 	mutex_exit(p->p_lock);
1317 
1318 	/* If there is a credential to be released, free it now. */
1319 	if (fcred != NULL) {
1320 		KASSERT(scred != NULL);
1321 		kauth_cred_free(fcred);
1322 		if (oc != scred)
1323 			kauth_cred_free(oc);
1324 	}
1325 }
1326 
1327 /*
1328  * proc_specific_key_create --
1329  *	Create a key for subsystem proc-specific data.
1330  */
1331 int
1332 proc_specific_key_create(specificdata_key_t *keyp, specificdata_dtor_t dtor)
1333 {
1334 
1335 	return (specificdata_key_create(proc_specificdata_domain, keyp, dtor));
1336 }
1337 
1338 /*
1339  * proc_specific_key_delete --
1340  *	Delete a key for subsystem proc-specific data.
1341  */
1342 void
1343 proc_specific_key_delete(specificdata_key_t key)
1344 {
1345 
1346 	specificdata_key_delete(proc_specificdata_domain, key);
1347 }
1348 
1349 /*
1350  * proc_initspecific --
1351  *	Initialize a proc's specificdata container.
1352  */
1353 void
1354 proc_initspecific(struct proc *p)
1355 {
1356 	int error;
1357 
1358 	error = specificdata_init(proc_specificdata_domain, &p->p_specdataref);
1359 	KASSERT(error == 0);
1360 }
1361 
1362 /*
1363  * proc_finispecific --
1364  *	Finalize a proc's specificdata container.
1365  */
1366 void
1367 proc_finispecific(struct proc *p)
1368 {
1369 
1370 	specificdata_fini(proc_specificdata_domain, &p->p_specdataref);
1371 }
1372 
1373 /*
1374  * proc_getspecific --
1375  *	Return proc-specific data corresponding to the specified key.
1376  */
1377 void *
1378 proc_getspecific(struct proc *p, specificdata_key_t key)
1379 {
1380 
1381 	return (specificdata_getspecific(proc_specificdata_domain,
1382 					 &p->p_specdataref, key));
1383 }
1384 
1385 /*
1386  * proc_setspecific --
1387  *	Set proc-specific data corresponding to the specified key.
1388  */
1389 void
1390 proc_setspecific(struct proc *p, specificdata_key_t key, void *data)
1391 {
1392 
1393 	specificdata_setspecific(proc_specificdata_domain,
1394 				 &p->p_specdataref, key, data);
1395 }
1396 
1397 int
1398 proc_uidmatch(kauth_cred_t cred, kauth_cred_t target)
1399 {
1400 	int r = 0;
1401 
1402 	if (kauth_cred_getuid(cred) != kauth_cred_getuid(target) ||
1403 	    kauth_cred_getuid(cred) != kauth_cred_getsvuid(target)) {
1404 		/*
1405 		 * suid proc of ours or proc not ours
1406 		 */
1407 		r = EPERM;
1408 	} else if (kauth_cred_getgid(target) != kauth_cred_getsvgid(target)) {
1409 		/*
1410 		 * sgid proc has sgid back to us temporarily
1411 		 */
1412 		r = EPERM;
1413 	} else {
1414 		/*
1415 		 * our rgid must be in target's group list (ie,
1416 		 * sub-processes started by a sgid process)
1417 		 */
1418 		int ismember = 0;
1419 
1420 		if (kauth_cred_ismember_gid(cred,
1421 		    kauth_cred_getgid(target), &ismember) != 0 ||
1422 		    !ismember)
1423 			r = EPERM;
1424 	}
1425 
1426 	return (r);
1427 }
1428 
1429