xref: /freebsd/lib/libkvm/kvm_proc.c (revision 076b94438c7d42c1b4661ed1e12e3b12ca69361a)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software developed by the Computer Systems
8  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
9  * BG 91-66 and contributed to Berkeley.
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  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 __SCCSID("@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93");
39 
40 /*
41  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
42  * users of this code, so we've factored it out into a separate module.
43  * Thus, we keep this grunge out of the other kvm applications (i.e.,
44  * most other applications are interested only in open/close/read/nlist).
45  */
46 
47 #include <sys/param.h>
48 #define	_WANT_UCRED	/* make ucred.h give us 'struct ucred' */
49 #include <sys/ucred.h>
50 #include <sys/queue.h>
51 #include <sys/_lock.h>
52 #include <sys/_mutex.h>
53 #include <sys/_task.h>
54 #include <sys/cpuset.h>
55 #include <sys/user.h>
56 #include <sys/proc.h>
57 #define	_WANT_PRISON	/* make jail.h give us 'struct prison' */
58 #include <sys/jail.h>
59 #include <sys/exec.h>
60 #include <sys/stat.h>
61 #include <sys/sysent.h>
62 #include <sys/ioctl.h>
63 #include <sys/tty.h>
64 #include <sys/file.h>
65 #include <sys/conf.h>
66 #define	_WANT_KW_EXITCODE
67 #include <sys/wait.h>
68 #include <stdio.h>
69 #include <stdlib.h>
70 #include <unistd.h>
71 #include <nlist.h>
72 #include <kvm.h>
73 
74 #include <sys/sysctl.h>
75 
76 #include <limits.h>
77 #include <memory.h>
78 #include <paths.h>
79 
80 #include "kvm_private.h"
81 
82 #define KREAD(kd, addr, obj) \
83 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
84 
85 static int ticks;
86 static int hz;
87 static uint64_t cpu_tick_frequency;
88 
89 /*
90  * From sys/kern/kern_tc.c. Depends on cpu_tick_frequency, which is
91  * read/initialized before this function is ever called.
92  */
93 static uint64_t
94 cputick2usec(uint64_t tick)
95 {
96 
97 	if (cpu_tick_frequency == 0)
98 		return (0);
99 	if (tick > 18446744073709551)		/* floor(2^64 / 1000) */
100 		return (tick / (cpu_tick_frequency / 1000000));
101 	else if (tick > 18446744073709)	/* floor(2^64 / 1000000) */
102 		return ((tick * 1000) / (cpu_tick_frequency / 1000));
103 	else
104 		return ((tick * 1000000) / cpu_tick_frequency);
105 }
106 
107 /*
108  * Read proc's from memory file into buffer bp, which has space to hold
109  * at most maxcnt procs.
110  */
111 static int
112 kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
113     struct kinfo_proc *bp, int maxcnt)
114 {
115 	int cnt = 0;
116 	struct kinfo_proc kinfo_proc, *kp;
117 	struct pgrp pgrp;
118 	struct session sess;
119 	struct cdev t_cdev;
120 	struct tty tty;
121 	struct vmspace vmspace;
122 	struct sigacts sigacts;
123 #if 0
124 	struct pstats pstats;
125 #endif
126 	struct ucred ucred;
127 	struct prison pr;
128 	struct thread mtd;
129 	struct proc proc;
130 	struct proc pproc;
131 	struct sysentvec sysent;
132 	char svname[KI_EMULNAMELEN];
133 
134 	kp = &kinfo_proc;
135 	kp->ki_structsize = sizeof(kinfo_proc);
136 	/*
137 	 * Loop on the processes. this is completely broken because we need to be
138 	 * able to loop on the threads and merge the ones that are the same process some how.
139 	 */
140 	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
141 		memset(kp, 0, sizeof *kp);
142 		if (KREAD(kd, (u_long)p, &proc)) {
143 			_kvm_err(kd, kd->program, "can't read proc at %p", p);
144 			return (-1);
145 		}
146 		if (proc.p_state == PRS_NEW)
147 			continue;
148 		if (proc.p_state != PRS_ZOMBIE) {
149 			if (KREAD(kd, (u_long)TAILQ_FIRST(&proc.p_threads),
150 			    &mtd)) {
151 				_kvm_err(kd, kd->program,
152 				    "can't read thread at %p",
153 				    TAILQ_FIRST(&proc.p_threads));
154 				return (-1);
155 			}
156 		}
157 		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
158 			kp->ki_ruid = ucred.cr_ruid;
159 			kp->ki_svuid = ucred.cr_svuid;
160 			kp->ki_rgid = ucred.cr_rgid;
161 			kp->ki_svgid = ucred.cr_svgid;
162 			kp->ki_cr_flags = ucred.cr_flags;
163 			if (ucred.cr_ngroups > KI_NGROUPS) {
164 				kp->ki_ngroups = KI_NGROUPS;
165 				kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
166 			} else
167 				kp->ki_ngroups = ucred.cr_ngroups;
168 			kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups,
169 			    kp->ki_ngroups * sizeof(gid_t));
170 			kp->ki_uid = ucred.cr_uid;
171 			if (ucred.cr_prison != NULL) {
172 				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
173 					_kvm_err(kd, kd->program,
174 					    "can't read prison at %p",
175 					    ucred.cr_prison);
176 					return (-1);
177 				}
178 				kp->ki_jid = pr.pr_id;
179 			}
180 		}
181 
182 		switch(what & ~KERN_PROC_INC_THREAD) {
183 
184 		case KERN_PROC_GID:
185 			if (kp->ki_groups[0] != (gid_t)arg)
186 				continue;
187 			break;
188 
189 		case KERN_PROC_PID:
190 			if (proc.p_pid != (pid_t)arg)
191 				continue;
192 			break;
193 
194 		case KERN_PROC_RGID:
195 			if (kp->ki_rgid != (gid_t)arg)
196 				continue;
197 			break;
198 
199 		case KERN_PROC_UID:
200 			if (kp->ki_uid != (uid_t)arg)
201 				continue;
202 			break;
203 
204 		case KERN_PROC_RUID:
205 			if (kp->ki_ruid != (uid_t)arg)
206 				continue;
207 			break;
208 		}
209 		/*
210 		 * We're going to add another proc to the set.  If this
211 		 * will overflow the buffer, assume the reason is because
212 		 * nprocs (or the proc list) is corrupt and declare an error.
213 		 */
214 		if (cnt >= maxcnt) {
215 			_kvm_err(kd, kd->program, "nprocs corrupt");
216 			return (-1);
217 		}
218 		/*
219 		 * gather kinfo_proc
220 		 */
221 		kp->ki_paddr = p;
222 		kp->ki_addr = 0;	/* XXX uarea */
223 		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
224 		kp->ki_args = proc.p_args;
225 		kp->ki_tracep = proc.p_tracevp;
226 		kp->ki_textvp = proc.p_textvp;
227 		kp->ki_fd = proc.p_fd;
228 		kp->ki_vmspace = proc.p_vmspace;
229 		if (proc.p_sigacts != NULL) {
230 			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
231 				_kvm_err(kd, kd->program,
232 				    "can't read sigacts at %p", proc.p_sigacts);
233 				return (-1);
234 			}
235 			kp->ki_sigignore = sigacts.ps_sigignore;
236 			kp->ki_sigcatch = sigacts.ps_sigcatch;
237 		}
238 #if 0
239 		if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
240 			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
241 				_kvm_err(kd, kd->program,
242 				    "can't read stats at %x", proc.p_stats);
243 				return (-1);
244 			}
245 			kp->ki_start = pstats.p_start;
246 
247 			/*
248 			 * XXX: The times here are probably zero and need
249 			 * to be calculated from the raw data in p_rux and
250 			 * p_crux.
251 			 */
252 			kp->ki_rusage = pstats.p_ru;
253 			kp->ki_childstime = pstats.p_cru.ru_stime;
254 			kp->ki_childutime = pstats.p_cru.ru_utime;
255 			/* Some callers want child-times in a single value */
256 			timeradd(&kp->ki_childstime, &kp->ki_childutime,
257 			    &kp->ki_childtime);
258 		}
259 #endif
260 		if (proc.p_oppid)
261 			kp->ki_ppid = proc.p_oppid;
262 		else if (proc.p_pptr) {
263 			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
264 				_kvm_err(kd, kd->program,
265 				    "can't read pproc at %p", proc.p_pptr);
266 				return (-1);
267 			}
268 			kp->ki_ppid = pproc.p_pid;
269 		} else
270 			kp->ki_ppid = 0;
271 		if (proc.p_pgrp == NULL)
272 			goto nopgrp;
273 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
274 			_kvm_err(kd, kd->program, "can't read pgrp at %p",
275 				 proc.p_pgrp);
276 			return (-1);
277 		}
278 		kp->ki_pgid = pgrp.pg_id;
279 		kp->ki_jobc = pgrp.pg_jobc;
280 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
281 			_kvm_err(kd, kd->program, "can't read session at %p",
282 				pgrp.pg_session);
283 			return (-1);
284 		}
285 		kp->ki_sid = sess.s_sid;
286 		(void)memcpy(kp->ki_login, sess.s_login,
287 						sizeof(kp->ki_login));
288 		kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
289 		if (sess.s_leader == p)
290 			kp->ki_kiflag |= KI_SLEADER;
291 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
292 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
293 				_kvm_err(kd, kd->program,
294 					 "can't read tty at %p", sess.s_ttyp);
295 				return (-1);
296 			}
297 			if (tty.t_dev != NULL) {
298 				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
299 					_kvm_err(kd, kd->program,
300 						 "can't read cdev at %p",
301 						tty.t_dev);
302 					return (-1);
303 				}
304 #if 0
305 				kp->ki_tdev = t_cdev.si_udev;
306 #else
307 				kp->ki_tdev = NODEV;
308 #endif
309 			}
310 			if (tty.t_pgrp != NULL) {
311 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
312 					_kvm_err(kd, kd->program,
313 						 "can't read tpgrp at %p",
314 						tty.t_pgrp);
315 					return (-1);
316 				}
317 				kp->ki_tpgid = pgrp.pg_id;
318 			} else
319 				kp->ki_tpgid = -1;
320 			if (tty.t_session != NULL) {
321 				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
322 					_kvm_err(kd, kd->program,
323 					    "can't read session at %p",
324 					    tty.t_session);
325 					return (-1);
326 				}
327 				kp->ki_tsid = sess.s_sid;
328 			}
329 		} else {
330 nopgrp:
331 			kp->ki_tdev = NODEV;
332 		}
333 		if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
334 			(void)kvm_read(kd, (u_long)mtd.td_wmesg,
335 			    kp->ki_wmesg, WMESGLEN);
336 
337 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
338 		    (char *)&vmspace, sizeof(vmspace));
339 		kp->ki_size = vmspace.vm_map.size;
340 		/*
341 		 * Approximate the kernel's method of calculating
342 		 * this field.
343 		 */
344 #define		pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
345 		kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap);
346 		kp->ki_swrss = vmspace.vm_swrss;
347 		kp->ki_tsize = vmspace.vm_tsize;
348 		kp->ki_dsize = vmspace.vm_dsize;
349 		kp->ki_ssize = vmspace.vm_ssize;
350 
351 		switch (what & ~KERN_PROC_INC_THREAD) {
352 
353 		case KERN_PROC_PGRP:
354 			if (kp->ki_pgid != (pid_t)arg)
355 				continue;
356 			break;
357 
358 		case KERN_PROC_SESSION:
359 			if (kp->ki_sid != (pid_t)arg)
360 				continue;
361 			break;
362 
363 		case KERN_PROC_TTY:
364 			if ((proc.p_flag & P_CONTROLT) == 0 ||
365 			     kp->ki_tdev != (dev_t)arg)
366 				continue;
367 			break;
368 		}
369 		if (proc.p_comm[0] != 0)
370 			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
371 		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
372 		    sizeof(sysent));
373 		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
374 		    sizeof(svname));
375 		if (svname[0] != 0)
376 			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
377 		if ((proc.p_state != PRS_ZOMBIE) &&
378 		    (mtd.td_blocked != 0)) {
379 			kp->ki_kiflag |= KI_LOCKBLOCK;
380 			if (mtd.td_lockname)
381 				(void)kvm_read(kd,
382 				    (u_long)mtd.td_lockname,
383 				    kp->ki_lockname, LOCKNAMELEN);
384 			kp->ki_lockname[LOCKNAMELEN] = 0;
385 		}
386 		kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
387 		kp->ki_pid = proc.p_pid;
388 		kp->ki_siglist = proc.p_siglist;
389 		SIGSETOR(kp->ki_siglist, mtd.td_siglist);
390 		kp->ki_sigmask = mtd.td_sigmask;
391 		kp->ki_xstat = KW_EXITCODE(proc.p_xexit, proc.p_xsig);
392 		kp->ki_acflag = proc.p_acflag;
393 		kp->ki_lock = proc.p_lock;
394 		if (proc.p_state != PRS_ZOMBIE) {
395 			kp->ki_swtime = (ticks - proc.p_swtick) / hz;
396 			kp->ki_flag = proc.p_flag;
397 			kp->ki_sflag = 0;
398 			kp->ki_nice = proc.p_nice;
399 			kp->ki_traceflag = proc.p_traceflag;
400 			if (proc.p_state == PRS_NORMAL) {
401 				if (TD_ON_RUNQ(&mtd) ||
402 				    TD_CAN_RUN(&mtd) ||
403 				    TD_IS_RUNNING(&mtd)) {
404 					kp->ki_stat = SRUN;
405 				} else if (mtd.td_state ==
406 				    TDS_INHIBITED) {
407 					if (P_SHOULDSTOP(&proc)) {
408 						kp->ki_stat = SSTOP;
409 					} else if (
410 					    TD_IS_SLEEPING(&mtd)) {
411 						kp->ki_stat = SSLEEP;
412 					} else if (TD_ON_LOCK(&mtd)) {
413 						kp->ki_stat = SLOCK;
414 					} else {
415 						kp->ki_stat = SWAIT;
416 					}
417 				}
418 			} else {
419 				kp->ki_stat = SIDL;
420 			}
421 			/* Stuff from the thread */
422 			kp->ki_pri.pri_level = mtd.td_priority;
423 			kp->ki_pri.pri_native = mtd.td_base_pri;
424 			kp->ki_lastcpu = mtd.td_lastcpu;
425 			kp->ki_wchan = mtd.td_wchan;
426 			kp->ki_oncpu = mtd.td_oncpu;
427 			if (mtd.td_name[0] != '\0')
428 				strlcpy(kp->ki_tdname, mtd.td_name, sizeof(kp->ki_tdname));
429 			kp->ki_pctcpu = 0;
430 			kp->ki_rqindex = 0;
431 
432 			/*
433 			 * Note: legacy fields; wraps at NO_CPU_OLD or the
434 			 * old max CPU value as appropriate
435 			 */
436 			if (mtd.td_lastcpu == NOCPU)
437 				kp->ki_lastcpu_old = NOCPU_OLD;
438 			else if (mtd.td_lastcpu > MAXCPU_OLD)
439 				kp->ki_lastcpu_old = MAXCPU_OLD;
440 			else
441 				kp->ki_lastcpu_old = mtd.td_lastcpu;
442 
443 			if (mtd.td_oncpu == NOCPU)
444 				kp->ki_oncpu_old = NOCPU_OLD;
445 			else if (mtd.td_oncpu > MAXCPU_OLD)
446 				kp->ki_oncpu_old = MAXCPU_OLD;
447 			else
448 				kp->ki_oncpu_old = mtd.td_oncpu;
449 		} else {
450 			kp->ki_stat = SZOMB;
451 		}
452 		kp->ki_tdev_freebsd11 = kp->ki_tdev; /* truncate */
453 		bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
454 		++bp;
455 		++cnt;
456 	}
457 	return (cnt);
458 }
459 
460 /*
461  * Build proc info array by reading in proc list from a crash dump.
462  * Return number of procs read.  maxcnt is the max we will read.
463  */
464 static int
465 kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
466     u_long a_zombproc, int maxcnt)
467 {
468 	struct kinfo_proc *bp = kd->procbase;
469 	int acnt, zcnt;
470 	struct proc *p;
471 
472 	if (KREAD(kd, a_allproc, &p)) {
473 		_kvm_err(kd, kd->program, "cannot read allproc");
474 		return (-1);
475 	}
476 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
477 	if (acnt < 0)
478 		return (acnt);
479 
480 	if (KREAD(kd, a_zombproc, &p)) {
481 		_kvm_err(kd, kd->program, "cannot read zombproc");
482 		return (-1);
483 	}
484 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
485 	if (zcnt < 0)
486 		zcnt = 0;
487 
488 	return (acnt + zcnt);
489 }
490 
491 struct kinfo_proc *
492 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
493 {
494 	int mib[4], st, nprocs;
495 	size_t size, osize;
496 	int temp_op;
497 
498 	if (kd->procbase != 0) {
499 		free((void *)kd->procbase);
500 		/*
501 		 * Clear this pointer in case this call fails.  Otherwise,
502 		 * kvm_close() will free it again.
503 		 */
504 		kd->procbase = 0;
505 	}
506 	if (ISALIVE(kd)) {
507 		size = 0;
508 		mib[0] = CTL_KERN;
509 		mib[1] = KERN_PROC;
510 		mib[2] = op;
511 		mib[3] = arg;
512 		temp_op = op & ~KERN_PROC_INC_THREAD;
513 		st = sysctl(mib,
514 		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
515 		    3 : 4, NULL, &size, NULL, 0);
516 		if (st == -1) {
517 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
518 			return (0);
519 		}
520 		/*
521 		 * We can't continue with a size of 0 because we pass
522 		 * it to realloc() (via _kvm_realloc()), and passing 0
523 		 * to realloc() results in undefined behavior.
524 		 */
525 		if (size == 0) {
526 			/*
527 			 * XXX: We should probably return an invalid,
528 			 * but non-NULL, pointer here so any client
529 			 * program trying to dereference it will
530 			 * crash.  However, _kvm_freeprocs() calls
531 			 * free() on kd->procbase if it isn't NULL,
532 			 * and free()'ing a junk pointer isn't good.
533 			 * Then again, _kvm_freeprocs() isn't used
534 			 * anywhere . . .
535 			 */
536 			kd->procbase = _kvm_malloc(kd, 1);
537 			goto liveout;
538 		}
539 		do {
540 			size += size / 10;
541 			kd->procbase = (struct kinfo_proc *)
542 			    _kvm_realloc(kd, kd->procbase, size);
543 			if (kd->procbase == NULL)
544 				return (0);
545 			osize = size;
546 			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
547 			    temp_op == KERN_PROC_PROC ? 3 : 4,
548 			    kd->procbase, &size, NULL, 0);
549 		} while (st == -1 && errno == ENOMEM && size == osize);
550 		if (st == -1) {
551 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
552 			return (0);
553 		}
554 		/*
555 		 * We have to check the size again because sysctl()
556 		 * may "round up" oldlenp if oldp is NULL; hence it
557 		 * might've told us that there was data to get when
558 		 * there really isn't any.
559 		 */
560 		if (size > 0 &&
561 		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
562 			_kvm_err(kd, kd->program,
563 			    "kinfo_proc size mismatch (expected %zu, got %d)",
564 			    sizeof(struct kinfo_proc),
565 			    kd->procbase->ki_structsize);
566 			return (0);
567 		}
568 liveout:
569 		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
570 	} else {
571 		struct nlist nl[7], *p;
572 
573 		nl[0].n_name = "_nprocs";
574 		nl[1].n_name = "_allproc";
575 		nl[2].n_name = "_zombproc";
576 		nl[3].n_name = "_ticks";
577 		nl[4].n_name = "_hz";
578 		nl[5].n_name = "_cpu_tick_frequency";
579 		nl[6].n_name = 0;
580 
581 		if (!kd->arch->ka_native(kd)) {
582 			_kvm_err(kd, kd->program,
583 			    "cannot read procs from non-native core");
584 			return (0);
585 		}
586 
587 		if (kvm_nlist(kd, nl) != 0) {
588 			for (p = nl; p->n_type != 0; ++p)
589 				;
590 			_kvm_err(kd, kd->program,
591 				 "%s: no such symbol", p->n_name);
592 			return (0);
593 		}
594 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
595 			_kvm_err(kd, kd->program, "can't read nprocs");
596 			return (0);
597 		}
598 		if (KREAD(kd, nl[3].n_value, &ticks)) {
599 			_kvm_err(kd, kd->program, "can't read ticks");
600 			return (0);
601 		}
602 		if (KREAD(kd, nl[4].n_value, &hz)) {
603 			_kvm_err(kd, kd->program, "can't read hz");
604 			return (0);
605 		}
606 		if (KREAD(kd, nl[5].n_value, &cpu_tick_frequency)) {
607 			_kvm_err(kd, kd->program,
608 			    "can't read cpu_tick_frequency");
609 			return (0);
610 		}
611 		size = nprocs * sizeof(struct kinfo_proc);
612 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
613 		if (kd->procbase == NULL)
614 			return (0);
615 
616 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
617 				      nl[2].n_value, nprocs);
618 		if (nprocs <= 0) {
619 			_kvm_freeprocs(kd);
620 			nprocs = 0;
621 		}
622 #ifdef notdef
623 		else {
624 			size = nprocs * sizeof(struct kinfo_proc);
625 			kd->procbase = realloc(kd->procbase, size);
626 		}
627 #endif
628 	}
629 	*cnt = nprocs;
630 	return (kd->procbase);
631 }
632 
633 void
634 _kvm_freeprocs(kvm_t *kd)
635 {
636 
637 	free(kd->procbase);
638 	kd->procbase = NULL;
639 }
640 
641 void *
642 _kvm_realloc(kvm_t *kd, void *p, size_t n)
643 {
644 	void *np;
645 
646 	np = reallocf(p, n);
647 	if (np == NULL)
648 		_kvm_err(kd, kd->program, "out of memory");
649 	return (np);
650 }
651 
652 /*
653  * Get the command args or environment.
654  */
655 static char **
656 kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
657 {
658 	int oid[4];
659 	int i;
660 	size_t bufsz;
661 	static int buflen;
662 	static char *buf, *p;
663 	static char **bufp;
664 	static int argc;
665 	char **nbufp;
666 
667 	if (!ISALIVE(kd)) {
668 		_kvm_err(kd, kd->program,
669 		    "cannot read user space from dead kernel");
670 		return (NULL);
671 	}
672 
673 	if (nchr == 0 || nchr > ARG_MAX)
674 		nchr = ARG_MAX;
675 	if (buflen == 0) {
676 		buf = malloc(nchr);
677 		if (buf == NULL) {
678 			_kvm_err(kd, kd->program, "cannot allocate memory");
679 			return (NULL);
680 		}
681 		argc = 32;
682 		bufp = malloc(sizeof(char *) * argc);
683 		if (bufp == NULL) {
684 			free(buf);
685 			buf = NULL;
686 			_kvm_err(kd, kd->program, "cannot allocate memory");
687 			return (NULL);
688 		}
689 		buflen = nchr;
690 	} else if (nchr > buflen) {
691 		p = realloc(buf, nchr);
692 		if (p != NULL) {
693 			buf = p;
694 			buflen = nchr;
695 		}
696 	}
697 	oid[0] = CTL_KERN;
698 	oid[1] = KERN_PROC;
699 	oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
700 	oid[3] = kp->ki_pid;
701 	bufsz = buflen;
702 	if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
703 		/*
704 		 * If the supplied buf is too short to hold the requested
705 		 * value the sysctl returns with ENOMEM. The buf is filled
706 		 * with the truncated value and the returned bufsz is equal
707 		 * to the requested len.
708 		 */
709 		if (errno != ENOMEM || bufsz != (size_t)buflen)
710 			return (NULL);
711 		buf[bufsz - 1] = '\0';
712 		errno = 0;
713 	} else if (bufsz == 0)
714 		return (NULL);
715 	i = 0;
716 	p = buf;
717 	do {
718 		bufp[i++] = p;
719 		p += strlen(p) + 1;
720 		if (i >= argc) {
721 			argc += argc;
722 			nbufp = realloc(bufp, sizeof(char *) * argc);
723 			if (nbufp == NULL)
724 				return (NULL);
725 			bufp = nbufp;
726 		}
727 	} while (p < buf + bufsz);
728 	bufp[i++] = 0;
729 	return (bufp);
730 }
731 
732 char **
733 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
734 {
735 	return (kvm_argv(kd, kp, 0, nchr));
736 }
737 
738 char **
739 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
740 {
741 	return (kvm_argv(kd, kp, 1, nchr));
742 }
743