File: kvm_proc.c

package info (click to toggle)
freebsd-libs 10.3~svn296373-10
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 6,564 kB
  • ctags: 9,832
  • sloc: ansic: 107,913; makefile: 1,101; sh: 72
file content (720 lines) | stat: -rw-r--r-- 19,415 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
/*-
 * Copyright (c) 1989, 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software developed by the Computer Systems
 * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
 * BG 91-66 and contributed to Berkeley.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if 0
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
#endif /* LIBC_SCCS and not lint */
#endif

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/*
 * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
 * users of this code, so we've factored it out into a separate module.
 * Thus, we keep this grunge out of the other kvm applications (i.e.,
 * most other applications are interested only in open/close/read/nlist).
 */

#include <sys/param.h>
#define	_WANT_UCRED	/* make ucred.h give us 'struct ucred' */
#include <sys/ucred.h>
#include <sys/queue.h>
#include <sys/_lock.h>
#include <sys/_mutex.h>
#include <sys/_task.h>
#include <sys/cpuset.h>
#include <sys/user.h>
#include <sys/proc.h>
#define	_WANT_PRISON	/* make jail.h give us 'struct prison' */
#include <sys/jail.h>
#include <sys/exec.h>
#include <sys/stat.h>
#include <sys/sysent.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/file.h>
#include <sys/conf.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <nlist.h>
#include <kvm.h>

#include <sys/sysctl.h>

#include <limits.h>
#include <memory.h>
#include <paths.h>

#include "kvm_private.h"

#define KREAD(kd, addr, obj) \
	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))

static int ticks;
static int hz;
static uint64_t cpu_tick_frequency;

/*
 * From sys/kern/kern_tc.c. Depends on cpu_tick_frequency, which is
 * read/initialized before this function is ever called.
 */
static uint64_t
cputick2usec(uint64_t tick)
{

	if (cpu_tick_frequency == 0)
		return (0);
	if (tick > 18446744073709551)		/* floor(2^64 / 1000) */
		return (tick / (cpu_tick_frequency / 1000000));
	else if (tick > 18446744073709)	/* floor(2^64 / 1000000) */
		return ((tick * 1000) / (cpu_tick_frequency / 1000));
	else
		return ((tick * 1000000) / cpu_tick_frequency);
}

/*
 * Read proc's from memory file into buffer bp, which has space to hold
 * at most maxcnt procs.
 */
static int
kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
    struct kinfo_proc *bp, int maxcnt)
{
	int cnt = 0;
	struct kinfo_proc kinfo_proc, *kp;
	struct pgrp pgrp;
	struct session sess;
	struct cdev t_cdev;
	struct tty tty;
	struct vmspace vmspace;
	struct sigacts sigacts;
#if 0
	struct pstats pstats;
#endif
	struct ucred ucred;
	struct prison pr;
	struct thread mtd;
	struct proc proc;
	struct proc pproc;
	struct sysentvec sysent;
	char svname[KI_EMULNAMELEN];

	kp = &kinfo_proc;
	kp->ki_structsize = sizeof(kinfo_proc);
	/*
	 * Loop on the processes. this is completely broken because we need to be
	 * able to loop on the threads and merge the ones that are the same process some how.
	 */
	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
		memset(kp, 0, sizeof *kp);
		if (KREAD(kd, (u_long)p, &proc)) {
			_kvm_err(kd, kd->program, "can't read proc at %p", p);
			return (-1);
		}
		if (proc.p_state == PRS_NEW)
			continue;
		if (proc.p_state != PRS_ZOMBIE) {
			if (KREAD(kd, (u_long)TAILQ_FIRST(&proc.p_threads),
			    &mtd)) {
				_kvm_err(kd, kd->program,
				    "can't read thread at %p",
				    TAILQ_FIRST(&proc.p_threads));
				return (-1);
			}
		}
		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
			kp->ki_ruid = ucred.cr_ruid;
			kp->ki_svuid = ucred.cr_svuid;
			kp->ki_rgid = ucred.cr_rgid;
			kp->ki_svgid = ucred.cr_svgid;
			kp->ki_cr_flags = ucred.cr_flags;
			if (ucred.cr_ngroups > KI_NGROUPS) {
				kp->ki_ngroups = KI_NGROUPS;
				kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
			} else
				kp->ki_ngroups = ucred.cr_ngroups;
			kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups,
			    kp->ki_ngroups * sizeof(gid_t));
			kp->ki_uid = ucred.cr_uid;
			if (ucred.cr_prison != NULL) {
				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
					_kvm_err(kd, kd->program,
					    "can't read prison at %p",
					    ucred.cr_prison);
					return (-1);
				}
				kp->ki_jid = pr.pr_id;
			}
		}

		switch(what & ~KERN_PROC_INC_THREAD) {

		case KERN_PROC_GID:
			if (kp->ki_groups[0] != (gid_t)arg)
				continue;
			break;

		case KERN_PROC_PID:
			if (proc.p_pid != (pid_t)arg)
				continue;
			break;

		case KERN_PROC_RGID:
			if (kp->ki_rgid != (gid_t)arg)
				continue;
			break;

		case KERN_PROC_UID:
			if (kp->ki_uid != (uid_t)arg)
				continue;
			break;

		case KERN_PROC_RUID:
			if (kp->ki_ruid != (uid_t)arg)
				continue;
			break;
		}
		/*
		 * We're going to add another proc to the set.  If this
		 * will overflow the buffer, assume the reason is because
		 * nprocs (or the proc list) is corrupt and declare an error.
		 */
		if (cnt >= maxcnt) {
			_kvm_err(kd, kd->program, "nprocs corrupt");
			return (-1);
		}
		/*
		 * gather kinfo_proc
		 */
		kp->ki_paddr = p;
		kp->ki_addr = 0;	/* XXX uarea */
		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
		kp->ki_args = proc.p_args;
		kp->ki_tracep = proc.p_tracevp;
		kp->ki_textvp = proc.p_textvp;
		kp->ki_fd = proc.p_fd;
		kp->ki_vmspace = proc.p_vmspace;
		if (proc.p_sigacts != NULL) {
			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
				_kvm_err(kd, kd->program,
				    "can't read sigacts at %p", proc.p_sigacts);
				return (-1);
			}
			kp->ki_sigignore = sigacts.ps_sigignore;
			kp->ki_sigcatch = sigacts.ps_sigcatch;
		}
#if 0
		if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
				_kvm_err(kd, kd->program,
				    "can't read stats at %x", proc.p_stats);
				return (-1);
			}
			kp->ki_start = pstats.p_start;

			/*
			 * XXX: The times here are probably zero and need
			 * to be calculated from the raw data in p_rux and
			 * p_crux.
			 */
			kp->ki_rusage = pstats.p_ru;
			kp->ki_childstime = pstats.p_cru.ru_stime;
			kp->ki_childutime = pstats.p_cru.ru_utime;
			/* Some callers want child-times in a single value */
			timeradd(&kp->ki_childstime, &kp->ki_childutime,
			    &kp->ki_childtime);
		}
#endif
		if (proc.p_oppid)
			kp->ki_ppid = proc.p_oppid;
		else if (proc.p_pptr) {
			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
				_kvm_err(kd, kd->program,
				    "can't read pproc at %p", proc.p_pptr);
				return (-1);
			}
			kp->ki_ppid = pproc.p_pid;
		} else 
			kp->ki_ppid = 0;
		if (proc.p_pgrp == NULL)
			goto nopgrp;
		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
			_kvm_err(kd, kd->program, "can't read pgrp at %p",
				 proc.p_pgrp);
			return (-1);
		}
		kp->ki_pgid = pgrp.pg_id;
		kp->ki_jobc = pgrp.pg_jobc;
		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
			_kvm_err(kd, kd->program, "can't read session at %p",
				pgrp.pg_session);
			return (-1);
		}
		kp->ki_sid = sess.s_sid;
		(void)memcpy(kp->ki_login, sess.s_login,
						sizeof(kp->ki_login));
		kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
		if (sess.s_leader == p)
			kp->ki_kiflag |= KI_SLEADER;
		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
				_kvm_err(kd, kd->program,
					 "can't read tty at %p", sess.s_ttyp);
				return (-1);
			}
			if (tty.t_dev != NULL) {
				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
					_kvm_err(kd, kd->program,
						 "can't read cdev at %p",
						tty.t_dev);
					return (-1);
				}
#if 0
				kp->ki_tdev = t_cdev.si_udev;
#else
				kp->ki_tdev = NODEV;
#endif
			}
			if (tty.t_pgrp != NULL) {
				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
					_kvm_err(kd, kd->program,
						 "can't read tpgrp at %p",
						tty.t_pgrp);
					return (-1);
				}
				kp->ki_tpgid = pgrp.pg_id;
			} else
				kp->ki_tpgid = -1;
			if (tty.t_session != NULL) {
				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
					_kvm_err(kd, kd->program,
					    "can't read session at %p",
					    tty.t_session);
					return (-1);
				}
				kp->ki_tsid = sess.s_sid;
			}
		} else {
nopgrp:
			kp->ki_tdev = NODEV;
		}
		if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
			(void)kvm_read(kd, (u_long)mtd.td_wmesg,
			    kp->ki_wmesg, WMESGLEN);

		(void)kvm_read(kd, (u_long)proc.p_vmspace,
		    (char *)&vmspace, sizeof(vmspace));
		kp->ki_size = vmspace.vm_map.size;
		/*
		 * Approximate the kernel's method of calculating
		 * this field.
		 */
#define		pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
		kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap); 
		kp->ki_swrss = vmspace.vm_swrss;
		kp->ki_tsize = vmspace.vm_tsize;
		kp->ki_dsize = vmspace.vm_dsize;
		kp->ki_ssize = vmspace.vm_ssize;

		switch (what & ~KERN_PROC_INC_THREAD) {

		case KERN_PROC_PGRP:
			if (kp->ki_pgid != (pid_t)arg)
				continue;
			break;

		case KERN_PROC_SESSION:
			if (kp->ki_sid != (pid_t)arg)
				continue;
			break;

		case KERN_PROC_TTY:
			if ((proc.p_flag & P_CONTROLT) == 0 ||
			     kp->ki_tdev != (dev_t)arg)
				continue;
			break;
		}
		if (proc.p_comm[0] != 0)
			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
		    sizeof(sysent));
		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
		    sizeof(svname));
		if (svname[0] != 0)
			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
		if ((proc.p_state != PRS_ZOMBIE) &&
		    (mtd.td_blocked != 0)) {
			kp->ki_kiflag |= KI_LOCKBLOCK;
			if (mtd.td_lockname)
				(void)kvm_read(kd,
				    (u_long)mtd.td_lockname,
				    kp->ki_lockname, LOCKNAMELEN);
			kp->ki_lockname[LOCKNAMELEN] = 0;
		}
		kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
		kp->ki_pid = proc.p_pid;
		kp->ki_siglist = proc.p_siglist;
#define SIGSETOR(set1, set2)                                            \
        do {                                                            \
                int __i;                                                \
                for (__i = 0; __i < _SIG_WORDS; __i++)                  \
                        (set1).__bits[__i] |= (set2).__bits[__i];       \
        } while (0)
		SIGSETOR(kp->ki_siglist, mtd.td_siglist);
		kp->ki_sigmask = mtd.td_sigmask;
		kp->ki_xstat = proc.p_xstat;
		kp->ki_acflag = proc.p_acflag;
		kp->ki_lock = proc.p_lock;
		if (proc.p_state != PRS_ZOMBIE) {
			kp->ki_swtime = (ticks - proc.p_swtick) / hz;
			kp->ki_flag = proc.p_flag;
			kp->ki_sflag = 0;
			kp->ki_nice = proc.p_nice;
			kp->ki_traceflag = proc.p_traceflag;
			if (proc.p_state == PRS_NORMAL) { 
				if (TD_ON_RUNQ(&mtd) ||
				    TD_CAN_RUN(&mtd) ||
				    TD_IS_RUNNING(&mtd)) {
					kp->ki_stat = SRUN;
				} else if (mtd.td_state == 
				    TDS_INHIBITED) {
					if (P_SHOULDSTOP(&proc)) {
						kp->ki_stat = SSTOP;
					} else if (
					    TD_IS_SLEEPING(&mtd)) {
						kp->ki_stat = SSLEEP;
					} else if (TD_ON_LOCK(&mtd)) {
						kp->ki_stat = SLOCK;
					} else {
						kp->ki_stat = SWAIT;
					}
				}
			} else {
				kp->ki_stat = SIDL;
			}
			/* Stuff from the thread */
			kp->ki_pri.pri_level = mtd.td_priority;
			kp->ki_pri.pri_native = mtd.td_base_pri;
			kp->ki_lastcpu = mtd.td_lastcpu;
			kp->ki_wchan = mtd.td_wchan;
			if (mtd.td_name[0] != 0)
				strlcpy(kp->ki_tdname, mtd.td_name, MAXCOMLEN);
			kp->ki_oncpu = mtd.td_oncpu;
			if (mtd.td_name[0] != '\0')
				strlcpy(kp->ki_tdname, mtd.td_name, sizeof(kp->ki_tdname));
			kp->ki_pctcpu = 0;
			kp->ki_rqindex = 0;
		} else {
			kp->ki_stat = SZOMB;
		}
		bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
		++bp;
		++cnt;
	}
	return (cnt);
}

/*
 * Build proc info array by reading in proc list from a crash dump.
 * Return number of procs read.  maxcnt is the max we will read.
 */
static int
kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
    u_long a_zombproc, int maxcnt)
{
	struct kinfo_proc *bp = kd->procbase;
	int acnt, zcnt;
	struct proc *p;

	if (KREAD(kd, a_allproc, &p)) {
		_kvm_err(kd, kd->program, "cannot read allproc");
		return (-1);
	}
	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
	if (acnt < 0)
		return (acnt);

	if (KREAD(kd, a_zombproc, &p)) {
		_kvm_err(kd, kd->program, "cannot read zombproc");
		return (-1);
	}
	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
	if (zcnt < 0)
		zcnt = 0;

	return (acnt + zcnt);
}

struct kinfo_proc *
kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
{
	int mib[4], st, nprocs;
	size_t size, osize;
	int temp_op;

	if (kd->procbase != 0) {
		free((void *)kd->procbase);
		/*
		 * Clear this pointer in case this call fails.  Otherwise,
		 * kvm_close() will free it again.
		 */
		kd->procbase = 0;
	}
	if (ISALIVE(kd)) {
		size = 0;
		mib[0] = CTL_KERN;
		mib[1] = KERN_PROC;
		mib[2] = op;
		mib[3] = arg;
		temp_op = op & ~KERN_PROC_INC_THREAD;
		st = sysctl(mib,
		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
		    3 : 4, NULL, &size, NULL, 0);
		if (st == -1) {
			_kvm_syserr(kd, kd->program, "kvm_getprocs");
			return (0);
		}
		/*
		 * We can't continue with a size of 0 because we pass
		 * it to realloc() (via _kvm_realloc()), and passing 0
		 * to realloc() results in undefined behavior.
		 */
		if (size == 0) {
			/*
			 * XXX: We should probably return an invalid,
			 * but non-NULL, pointer here so any client
			 * program trying to dereference it will
			 * crash.  However, _kvm_freeprocs() calls
			 * free() on kd->procbase if it isn't NULL,
			 * and free()'ing a junk pointer isn't good.
			 * Then again, _kvm_freeprocs() isn't used
			 * anywhere . . .
			 */
			kd->procbase = _kvm_malloc(kd, 1);
			goto liveout;
		}
		do {
			size += size / 10;
			kd->procbase = (struct kinfo_proc *)
			    _kvm_realloc(kd, kd->procbase, size);
			if (kd->procbase == 0)
				return (0);
			osize = size;
			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
			    temp_op == KERN_PROC_PROC ? 3 : 4,
			    kd->procbase, &size, NULL, 0);
		} while (st == -1 && errno == ENOMEM && size == osize);
		if (st == -1) {
			_kvm_syserr(kd, kd->program, "kvm_getprocs");
			return (0);
		}
		/*
		 * We have to check the size again because sysctl()
		 * may "round up" oldlenp if oldp is NULL; hence it
		 * might've told us that there was data to get when
		 * there really isn't any.
		 */
		if (size > 0 &&
		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
			_kvm_err(kd, kd->program,
			    "kinfo_proc size mismatch (expected %zu, got %d)",
			    sizeof(struct kinfo_proc),
			    kd->procbase->ki_structsize);
			return (0);
		}
liveout:
		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
	} else {
		struct nlist nl[7], *p;

		nl[0].n_name = "_nprocs";
		nl[1].n_name = "_allproc";
		nl[2].n_name = "_zombproc";
		nl[3].n_name = "_ticks";
		nl[4].n_name = "_hz";
		nl[5].n_name = "_cpu_tick_frequency";
		nl[6].n_name = 0;

		if (kvm_nlist(kd, nl) != 0) {
			for (p = nl; p->n_type != 0; ++p)
				;
			_kvm_err(kd, kd->program,
				 "%s: no such symbol", p->n_name);
			return (0);
		}
		if (KREAD(kd, nl[0].n_value, &nprocs)) {
			_kvm_err(kd, kd->program, "can't read nprocs");
			return (0);
		}
		if (KREAD(kd, nl[3].n_value, &ticks)) {
			_kvm_err(kd, kd->program, "can't read ticks");
			return (0);
		}
		if (KREAD(kd, nl[4].n_value, &hz)) {
			_kvm_err(kd, kd->program, "can't read hz");
			return (0);
		}
		if (KREAD(kd, nl[5].n_value, &cpu_tick_frequency)) {
			_kvm_err(kd, kd->program,
			    "can't read cpu_tick_frequency");
			return (0);
		}
		size = nprocs * sizeof(struct kinfo_proc);
		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
		if (kd->procbase == 0)
			return (0);

		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
				      nl[2].n_value, nprocs);
		if (nprocs <= 0) {
			_kvm_freeprocs(kd);
			nprocs = 0;
		}
#ifdef notdef
		else {
			size = nprocs * sizeof(struct kinfo_proc);
			kd->procbase = realloc(kd->procbase, size);
		}
#endif
	}
	*cnt = nprocs;
	return (kd->procbase);
}

void
_kvm_freeprocs(kvm_t *kd)
{
	if (kd->procbase) {
		free(kd->procbase);
		kd->procbase = 0;
	}
}

void *
_kvm_realloc(kvm_t *kd, void *p, size_t n)
{
	void *np = (void *)realloc(p, n);

	if (np == 0) {
		free(p);
		_kvm_err(kd, kd->program, "out of memory");
	}
	return (np);
}

/*
 * Get the command args or environment.
 */
static char **
kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
{
	int oid[4];
	int i;
	size_t bufsz;
	static int buflen;
	static char *buf, *p;
	static char **bufp;
	static int argc;

	if (!ISALIVE(kd)) {
		_kvm_err(kd, kd->program,
		    "cannot read user space from dead kernel");
		return (0);
	}

	if (nchr == 0 || nchr > ARG_MAX)
		nchr = ARG_MAX;
	if (buflen == 0) {
		buf = malloc(nchr);
		if (buf == NULL) {
			_kvm_err(kd, kd->program, "cannot allocate memory");
			return (0);
		}
		buflen = nchr;
		argc = 32;
		bufp = malloc(sizeof(char *) * argc);
	} else if (nchr > buflen) {
		p = realloc(buf, nchr);
		if (p != NULL) {
			buf = p;
			buflen = nchr;
		}
	}
	oid[0] = CTL_KERN;
	oid[1] = KERN_PROC;
	oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
	oid[3] = kp->ki_pid;
	bufsz = buflen;
	if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
		/*
		 * If the supplied buf is too short to hold the requested
		 * value the sysctl returns with ENOMEM. The buf is filled
		 * with the truncated value and the returned bufsz is equal
		 * to the requested len.
		 */
		if (errno != ENOMEM || bufsz != (size_t)buflen)
			return (0);
		buf[bufsz - 1] = '\0';
		errno = 0;
	} else if (bufsz == 0) {
		return (0);
	}
	i = 0;
	p = buf;
	do {
		bufp[i++] = p;
		p += strlen(p) + 1;
		if (i >= argc) {
			argc += argc;
			bufp = realloc(bufp,
			    sizeof(char *) * argc);
		}
	} while (p < buf + bufsz);
	bufp[i++] = 0;
	return (bufp);
}

char **
kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
{
	return (kvm_argv(kd, kp, 0, nchr));
}

char **
kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
{
	return (kvm_argv(kd, kp, 1, nchr));
}