xref: /freebsd/lib/libkvm/kvm_proc.c (revision e27501388fc0dc2a29f90cb24ba8d36e9bb6631f)
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 
37 /*
38  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
39  * users of this code, so we've factored it out into a separate module.
40  * Thus, we keep this grunge out of the other kvm applications (i.e.,
41  * most other applications are interested only in open/close/read/nlist).
42  */
43 
44 #include <sys/param.h>
45 #define	_WANT_UCRED	/* make ucred.h give us 'struct ucred' */
46 #include <sys/ucred.h>
47 #include <sys/queue.h>
48 #include <sys/_lock.h>
49 #include <sys/_mutex.h>
50 #include <sys/_task.h>
51 #include <sys/cpuset.h>
52 #include <sys/user.h>
53 #include <sys/proc.h>
54 #define	_WANT_PRISON	/* make jail.h give us 'struct prison' */
55 #include <sys/jail.h>
56 #include <sys/exec.h>
57 #include <sys/stat.h>
58 #include <sys/sysent.h>
59 #include <sys/ioctl.h>
60 #include <sys/tty.h>
61 #include <sys/file.h>
62 #include <sys/conf.h>
63 #define	_WANT_KW_EXITCODE
64 #include <sys/wait.h>
65 #include <stdio.h>
66 #include <stdlib.h>
67 #include <stdbool.h>
68 #include <unistd.h>
69 #include <nlist.h>
70 #include <kvm.h>
71 
72 #include <sys/sysctl.h>
73 
74 #include <limits.h>
75 #include <memory.h>
76 #include <paths.h>
77 
78 #include "kvm_private.h"
79 
80 #define KREAD(kd, addr, obj) \
81 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
82 
83 static int ticks;
84 static int hz;
85 static uint64_t cpu_tick_frequency;
86 
87 /*
88  * From sys/kern/kern_tc.c. Depends on cpu_tick_frequency, which is
89  * read/initialized before this function is ever called.
90  */
91 static uint64_t
92 cputick2usec(uint64_t tick)
93 {
94 	if (cpu_tick_frequency == 0)
95 		return (0);
96 	return ((tick / cpu_tick_frequency) * 1000000ULL) +
97 	    ((tick % cpu_tick_frequency) * 1000000ULL) / cpu_tick_frequency;
98 }
99 
100 /*
101  * Read proc's from memory file into buffer bp, which has space to hold
102  * at most maxcnt procs.
103  */
104 static int
105 kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
106     struct kinfo_proc *bp, int maxcnt)
107 {
108 	int cnt = 0;
109 	struct kinfo_proc kinfo_proc, *kp;
110 	struct pgrp pgrp;
111 	struct session sess;
112 	struct cdev t_cdev;
113 	struct tty tty;
114 	struct vmspace vmspace;
115 	struct sigacts sigacts;
116 #if 0
117 	struct pstats pstats;
118 #endif
119 	struct ucred ucred;
120 	struct prison pr;
121 	struct thread mtd;
122 	struct proc proc;
123 	struct proc pproc;
124 	struct proc rproc;
125 	struct sysentvec sysent;
126 	char svname[KI_EMULNAMELEN];
127 	struct thread *td = NULL;
128 	bool first_thread;
129 
130 	kp = &kinfo_proc;
131 	kp->ki_structsize = sizeof(kinfo_proc);
132 	/*
133 	 * Loop on the processes, then threads within the process if requested.
134 	 */
135 	if (what == KERN_PROC_ALL)
136 		what |= KERN_PROC_INC_THREAD;
137 	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
138 		memset(kp, 0, sizeof *kp);
139 		if (KREAD(kd, (u_long)p, &proc)) {
140 			_kvm_err(kd, kd->program, "can't read proc at %p", p);
141 			return (-1);
142 		}
143 		if (proc.p_state == PRS_NEW)
144 			continue;
145 		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
146 			kp->ki_uid = ucred.cr_uid;
147 			kp->ki_ruid = ucred.cr_ruid;
148 			kp->ki_svuid = ucred.cr_svuid;
149 			kp->ki_rgid = ucred.cr_rgid;
150 			kp->ki_svgid = ucred.cr_svgid;
151 			kp->ki_cr_flags = 0;
152 			if (ucred.cr_flags & CRED_FLAG_CAPMODE)
153 				kp->ki_cr_flags |= KI_CRF_CAPABILITY_MODE;
154 			if (1 + ucred.cr_ngroups > KI_NGROUPS) {
155 				kp->ki_ngroups = KI_NGROUPS;
156 				kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
157 			} else
158 				kp->ki_ngroups = 1 + ucred.cr_ngroups;
159 			kp->ki_groups[0] = ucred.cr_gid;
160 			kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups + 1,
161 			    (kp->ki_ngroups - 1) * sizeof(gid_t));
162 			if (ucred.cr_prison != NULL) {
163 				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
164 					_kvm_err(kd, kd->program,
165 					    "can't read prison at %p",
166 					    ucred.cr_prison);
167 					return (-1);
168 				}
169 				kp->ki_jid = pr.pr_id;
170 			}
171 		}
172 
173 		switch(what & ~KERN_PROC_INC_THREAD) {
174 
175 		case KERN_PROC_GID:
176 			if (kp->ki_groups[0] != (gid_t)arg)
177 				continue;
178 			break;
179 
180 		case KERN_PROC_PID:
181 			if (proc.p_pid != (pid_t)arg)
182 				continue;
183 			break;
184 
185 		case KERN_PROC_RGID:
186 			if (kp->ki_rgid != (gid_t)arg)
187 				continue;
188 			break;
189 
190 		case KERN_PROC_UID:
191 			if (kp->ki_uid != (uid_t)arg)
192 				continue;
193 			break;
194 
195 		case KERN_PROC_RUID:
196 			if (kp->ki_ruid != (uid_t)arg)
197 				continue;
198 			break;
199 		}
200 		/*
201 		 * We're going to add another proc to the set.  If this
202 		 * will overflow the buffer, assume the reason is because
203 		 * nprocs (or the proc list) is corrupt and declare an error.
204 		 */
205 		if (cnt >= maxcnt) {
206 			_kvm_err(kd, kd->program, "nprocs corrupt");
207 			return (-1);
208 		}
209 		/*
210 		 * gather kinfo_proc
211 		 */
212 		kp->ki_paddr = p;
213 		kp->ki_addr = 0;	/* XXX uarea */
214 		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
215 		kp->ki_args = proc.p_args;
216 		kp->ki_numthreads = proc.p_numthreads;
217 		kp->ki_tracep = NULL;	/* XXXKIB do not expose ktr_io_params */
218 		kp->ki_textvp = proc.p_textvp;
219 		kp->ki_fd = proc.p_fd;
220 		kp->ki_pd = proc.p_pd;
221 		kp->ki_vmspace = proc.p_vmspace;
222 		if (proc.p_sigacts != NULL) {
223 			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
224 				_kvm_err(kd, kd->program,
225 				    "can't read sigacts at %p", proc.p_sigacts);
226 				return (-1);
227 			}
228 			kp->ki_sigignore = sigacts.ps_sigignore;
229 			kp->ki_sigcatch = sigacts.ps_sigcatch;
230 		}
231 #if 0
232 		if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
233 			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
234 				_kvm_err(kd, kd->program,
235 				    "can't read stats at %x", proc.p_stats);
236 				return (-1);
237 			}
238 			kp->ki_start = pstats.p_start;
239 
240 			/*
241 			 * XXX: The times here are probably zero and need
242 			 * to be calculated from the raw data in p_rux and
243 			 * p_crux.
244 			 */
245 			kp->ki_rusage = pstats.p_ru;
246 			kp->ki_childstime = pstats.p_cru.ru_stime;
247 			kp->ki_childutime = pstats.p_cru.ru_utime;
248 			/* Some callers want child-times in a single value */
249 			timeradd(&kp->ki_childstime, &kp->ki_childutime,
250 			    &kp->ki_childtime);
251 		}
252 #endif
253 		if (proc.p_oppid)
254 			kp->ki_ppid = proc.p_oppid;
255 		else if (proc.p_pptr) {
256 			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
257 				_kvm_err(kd, kd->program,
258 				    "can't read pproc at %p", proc.p_pptr);
259 				return (-1);
260 			}
261 			kp->ki_ppid = pproc.p_pid;
262 		} else
263 			kp->ki_ppid = 0;
264 		if (proc.p_pgrp == NULL)
265 			goto nopgrp;
266 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
267 			_kvm_err(kd, kd->program, "can't read pgrp at %p",
268 				 proc.p_pgrp);
269 			return (-1);
270 		}
271 		kp->ki_pgid = pgrp.pg_id;
272 		kp->ki_jobc = -1;	/* Or calculate?  Arguably not. */
273 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
274 			_kvm_err(kd, kd->program, "can't read session at %p",
275 				pgrp.pg_session);
276 			return (-1);
277 		}
278 		kp->ki_sid = sess.s_sid;
279 		(void)memcpy(kp->ki_login, sess.s_login,
280 						sizeof(kp->ki_login));
281 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
282 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
283 				_kvm_err(kd, kd->program,
284 					 "can't read tty at %p", sess.s_ttyp);
285 				return (-1);
286 			}
287 			if (tty.t_dev != NULL) {
288 				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
289 					_kvm_err(kd, kd->program,
290 						 "can't read cdev at %p",
291 						tty.t_dev);
292 					return (-1);
293 				}
294 #if 0
295 				kp->ki_tdev = t_cdev.si_udev;
296 #else
297 				kp->ki_tdev = NODEV;
298 #endif
299 			}
300 			if (tty.t_pgrp != NULL) {
301 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
302 					_kvm_err(kd, kd->program,
303 						 "can't read tpgrp at %p",
304 						tty.t_pgrp);
305 					return (-1);
306 				}
307 				kp->ki_tpgid = pgrp.pg_id;
308 			} else
309 				kp->ki_tpgid = -1;
310 			if (tty.t_session != NULL) {
311 				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
312 					_kvm_err(kd, kd->program,
313 					    "can't read session at %p",
314 					    tty.t_session);
315 					return (-1);
316 				}
317 				kp->ki_tsid = sess.s_sid;
318 			}
319 		} else {
320 nopgrp:
321 			kp->ki_tdev = NODEV;
322 		}
323 
324 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
325 		    (char *)&vmspace, sizeof(vmspace));
326 		kp->ki_size = vmspace.vm_map.size;
327 		/*
328 		 * Approximate the kernel's method of calculating
329 		 * this field.
330 		 */
331 #define		pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
332 		kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap);
333 		kp->ki_swrss = vmspace.vm_swrss;
334 		kp->ki_tsize = vmspace.vm_tsize;
335 		kp->ki_dsize = vmspace.vm_dsize;
336 		kp->ki_ssize = vmspace.vm_ssize;
337 
338 		switch (what & ~KERN_PROC_INC_THREAD) {
339 
340 		case KERN_PROC_PGRP:
341 			if (kp->ki_pgid != (pid_t)arg)
342 				continue;
343 			break;
344 
345 		case KERN_PROC_SESSION:
346 			if (kp->ki_sid != (pid_t)arg)
347 				continue;
348 			break;
349 
350 		case KERN_PROC_TTY:
351 			if ((proc.p_flag & P_CONTROLT) == 0 ||
352 			     kp->ki_tdev != (dev_t)arg)
353 				continue;
354 			break;
355 		}
356 		if (proc.p_comm[0] != 0)
357 			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
358 		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
359 		    sizeof(sysent));
360 		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
361 		    sizeof(svname));
362 		if (svname[0] != 0)
363 			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
364 		kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
365 		kp->ki_pid = proc.p_pid;
366 		kp->ki_xstat = KW_EXITCODE(proc.p_xexit, proc.p_xsig);
367 		kp->ki_acflag = proc.p_acflag;
368 		kp->ki_lock = proc.p_lock;
369 		if (KREAD(kd, (u_long)proc.p_reaper, &rproc)) {
370 			_kvm_err(kd, kd->program,
371 			    "can't read reaper at %p", proc.p_reaper);
372 			return (-1);
373 		}
374 		kp->ki_reaper = rproc.p_pid;
375 		kp->ki_reapsubtree = proc.p_reapsubtree;
376 		kp->ki_tdev_freebsd11 = kp->ki_tdev; /* truncate */
377 
378 		/* Per-thread items; iterate as appropriate. */
379 		td = TAILQ_FIRST(&proc.p_threads);
380 		for (first_thread = true; cnt < maxcnt && td != NULL &&
381 		    (first_thread || (what & KERN_PROC_INC_THREAD));
382 		    first_thread = false) {
383 			if (proc.p_state != PRS_ZOMBIE) {
384 				if (KREAD(kd, (u_long)td, &mtd)) {
385 					_kvm_err(kd, kd->program,
386 					    "can't read thread at %p", td);
387 					return (-1);
388 				}
389 				if (what & KERN_PROC_INC_THREAD)
390 					td = TAILQ_NEXT(&mtd, td_plist);
391 			} else
392 				td = NULL;
393 			if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
394 				(void)kvm_read(kd, (u_long)mtd.td_wmesg,
395 				    kp->ki_wmesg, WMESGLEN);
396 			else
397 				memset(kp->ki_wmesg, 0, WMESGLEN);
398 			if (proc.p_pgrp == NULL) {
399 				kp->ki_kiflag = 0;
400 			} else {
401 				kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
402 				if (sess.s_leader == p)
403 					kp->ki_kiflag |= KI_SLEADER;
404 			}
405 			if ((proc.p_state != PRS_ZOMBIE) &&
406 			    (mtd.td_blocked != 0)) {
407 				kp->ki_kiflag |= KI_LOCKBLOCK;
408 				if (mtd.td_lockname)
409 					(void)kvm_read(kd,
410 					    (u_long)mtd.td_lockname,
411 					    kp->ki_lockname, LOCKNAMELEN);
412 				else
413 					memset(kp->ki_lockname, 0,
414 					    LOCKNAMELEN);
415 				kp->ki_lockname[LOCKNAMELEN] = 0;
416 			} else
417 				kp->ki_kiflag &= ~KI_LOCKBLOCK;
418 			kp->ki_siglist = proc.p_siglist;
419 			if (proc.p_state != PRS_ZOMBIE) {
420 				SIGSETOR(kp->ki_siglist, mtd.td_siglist);
421 				kp->ki_sigmask = mtd.td_sigmask;
422 				kp->ki_swtime = (ticks - proc.p_swtick) / hz;
423 				kp->ki_flag = proc.p_flag;
424 				kp->ki_sflag = 0;
425 				kp->ki_nice = proc.p_nice;
426 				kp->ki_traceflag = proc.p_traceflag;
427 				if (proc.p_state == PRS_NORMAL) {
428 					if (TD_ON_RUNQ(&mtd) ||
429 					    TD_CAN_RUN(&mtd) ||
430 					    TD_IS_RUNNING(&mtd)) {
431 						kp->ki_stat = SRUN;
432 					} else if (TD_GET_STATE(&mtd) ==
433 					    TDS_INHIBITED) {
434 						if (P_SHOULDSTOP(&proc)) {
435 							kp->ki_stat = SSTOP;
436 						} else if (
437 						    TD_IS_SLEEPING(&mtd)) {
438 							kp->ki_stat = SSLEEP;
439 						} else if (TD_ON_LOCK(&mtd)) {
440 							kp->ki_stat = SLOCK;
441 						} else {
442 							kp->ki_stat = SWAIT;
443 						}
444 					}
445 				} else {
446 					kp->ki_stat = SIDL;
447 				}
448 				/* Stuff from the thread */
449 				kp->ki_pri.pri_level = mtd.td_priority;
450 				kp->ki_pri.pri_native = mtd.td_base_pri;
451 				kp->ki_lastcpu = mtd.td_lastcpu;
452 				kp->ki_wchan = mtd.td_wchan;
453 				kp->ki_oncpu = mtd.td_oncpu;
454 				if (mtd.td_name[0] != '\0')
455 					strlcpy(kp->ki_tdname, mtd.td_name,
456 					    sizeof(kp->ki_tdname));
457 				else
458 					memset(kp->ki_tdname, 0,
459 					    sizeof(kp->ki_tdname));
460 				kp->ki_pctcpu = 0;
461 				kp->ki_rqindex = 0;
462 
463 				/*
464 				 * Note: legacy fields; wraps at NO_CPU_OLD
465 				 * or the old max CPU value as appropriate
466 				 */
467 				if (mtd.td_lastcpu == NOCPU)
468 					kp->ki_lastcpu_old = NOCPU_OLD;
469 				else if (mtd.td_lastcpu > MAXCPU_OLD)
470 					kp->ki_lastcpu_old = MAXCPU_OLD;
471 				else
472 					kp->ki_lastcpu_old = mtd.td_lastcpu;
473 
474 				if (mtd.td_oncpu == NOCPU)
475 					kp->ki_oncpu_old = NOCPU_OLD;
476 				else if (mtd.td_oncpu > MAXCPU_OLD)
477 					kp->ki_oncpu_old = MAXCPU_OLD;
478 				else
479 					kp->ki_oncpu_old = mtd.td_oncpu;
480 				kp->ki_tid = mtd.td_tid;
481 			} else {
482 				memset(&kp->ki_sigmask, 0,
483 				    sizeof(kp->ki_sigmask));
484 				kp->ki_stat = SZOMB;
485 				kp->ki_tid = 0;
486 			}
487 
488 			bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
489 			++bp;
490 			++cnt;
491 		}
492 	}
493 	return (cnt);
494 }
495 
496 /*
497  * Build proc info array by reading in proc list from a crash dump.
498  * Return number of procs read.  maxcnt is the max we will read.
499  */
500 static int
501 kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
502     u_long a_zombproc, int maxcnt)
503 {
504 	struct kinfo_proc *bp = kd->procbase;
505 	int acnt, zcnt = 0;
506 	struct proc *p;
507 
508 	if (KREAD(kd, a_allproc, &p)) {
509 		_kvm_err(kd, kd->program, "cannot read allproc");
510 		return (-1);
511 	}
512 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
513 	if (acnt < 0)
514 		return (acnt);
515 
516 	if (a_zombproc != 0) {
517 		if (KREAD(kd, a_zombproc, &p)) {
518 			_kvm_err(kd, kd->program, "cannot read zombproc");
519 			return (-1);
520 		}
521 		zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
522 		if (zcnt < 0)
523 			zcnt = 0;
524 	}
525 
526 	return (acnt + zcnt);
527 }
528 
529 struct kinfo_proc *
530 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
531 {
532 	int mib[4], st, nprocs;
533 	size_t size, osize;
534 	int temp_op;
535 
536 	if (kd->procbase != 0) {
537 		free((void *)kd->procbase);
538 		/*
539 		 * Clear this pointer in case this call fails.  Otherwise,
540 		 * kvm_close() will free it again.
541 		 */
542 		kd->procbase = 0;
543 	}
544 	if (ISALIVE(kd)) {
545 		size = 0;
546 		mib[0] = CTL_KERN;
547 		mib[1] = KERN_PROC;
548 		mib[2] = op;
549 		mib[3] = arg;
550 		temp_op = op & ~KERN_PROC_INC_THREAD;
551 		st = sysctl(mib,
552 		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
553 		    3 : 4, NULL, &size, NULL, 0);
554 		if (st == -1) {
555 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
556 			return (0);
557 		}
558 		/*
559 		 * We can't continue with a size of 0 because we pass
560 		 * it to realloc() (via _kvm_realloc()), and passing 0
561 		 * to realloc() results in undefined behavior.
562 		 */
563 		if (size == 0) {
564 			/*
565 			 * XXX: We should probably return an invalid,
566 			 * but non-NULL, pointer here so any client
567 			 * program trying to dereference it will
568 			 * crash.  However, _kvm_freeprocs() calls
569 			 * free() on kd->procbase if it isn't NULL,
570 			 * and free()'ing a junk pointer isn't good.
571 			 * Then again, _kvm_freeprocs() isn't used
572 			 * anywhere . . .
573 			 */
574 			kd->procbase = _kvm_malloc(kd, 1);
575 			goto liveout;
576 		}
577 		do {
578 			size += size / 10;
579 			kd->procbase = (struct kinfo_proc *)
580 			    _kvm_realloc(kd, kd->procbase, size);
581 			if (kd->procbase == NULL)
582 				return (0);
583 			osize = size;
584 			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
585 			    temp_op == KERN_PROC_PROC ? 3 : 4,
586 			    kd->procbase, &size, NULL, 0);
587 		} while (st == -1 && errno == ENOMEM && size == osize);
588 		if (st == -1) {
589 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
590 			return (0);
591 		}
592 		/*
593 		 * We have to check the size again because sysctl()
594 		 * may "round up" oldlenp if oldp is NULL; hence it
595 		 * might've told us that there was data to get when
596 		 * there really isn't any.
597 		 */
598 		if (size > 0 &&
599 		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
600 			_kvm_err(kd, kd->program,
601 			    "kinfo_proc size mismatch (expected %zu, got %d)",
602 			    sizeof(struct kinfo_proc),
603 			    kd->procbase->ki_structsize);
604 			return (0);
605 		}
606 liveout:
607 		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
608 	} else {
609 		struct nlist nl[6], *p;
610 		struct nlist nlz[2];
611 
612 		nl[0].n_name = "_nprocs";
613 		nl[1].n_name = "_allproc";
614 		nl[2].n_name = "_ticks";
615 		nl[3].n_name = "_hz";
616 		nl[4].n_name = "_cpu_tick_frequency";
617 		nl[5].n_name = 0;
618 
619 		nlz[0].n_name = "_zombproc";
620 		nlz[1].n_name = 0;
621 
622 		if (!kd->arch->ka_native(kd)) {
623 			_kvm_err(kd, kd->program,
624 			    "cannot read procs from non-native core");
625 			return (0);
626 		}
627 
628 		if (kvm_nlist(kd, nl) != 0) {
629 			for (p = nl; p->n_type != 0; ++p)
630 				;
631 			_kvm_err(kd, kd->program,
632 				 "%s: no such symbol", p->n_name);
633 			return (0);
634 		}
635 		(void) kvm_nlist(kd, nlz);	/* attempt to get zombproc */
636 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
637 			_kvm_err(kd, kd->program, "can't read nprocs");
638 			return (0);
639 		}
640 		/*
641 		 * If returning all threads, we don't know how many that
642 		 * might be.  Presume that there are, on average, no more
643 		 * than 10 threads per process.
644 		 */
645 		if (op == KERN_PROC_ALL || (op & KERN_PROC_INC_THREAD))
646 			nprocs *= 10;		/* XXX */
647 		if (KREAD(kd, nl[2].n_value, &ticks)) {
648 			_kvm_err(kd, kd->program, "can't read ticks");
649 			return (0);
650 		}
651 		if (KREAD(kd, nl[3].n_value, &hz)) {
652 			_kvm_err(kd, kd->program, "can't read hz");
653 			return (0);
654 		}
655 		if (KREAD(kd, nl[4].n_value, &cpu_tick_frequency)) {
656 			_kvm_err(kd, kd->program,
657 			    "can't read cpu_tick_frequency");
658 			return (0);
659 		}
660 		size = nprocs * sizeof(struct kinfo_proc);
661 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
662 		if (kd->procbase == NULL)
663 			return (0);
664 
665 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
666 				      nlz[0].n_value, nprocs);
667 		if (nprocs <= 0) {
668 			_kvm_freeprocs(kd);
669 			nprocs = 0;
670 		}
671 #ifdef notdef
672 		else {
673 			size = nprocs * sizeof(struct kinfo_proc);
674 			kd->procbase = realloc(kd->procbase, size);
675 		}
676 #endif
677 	}
678 	*cnt = nprocs;
679 	return (kd->procbase);
680 }
681 
682 void
683 _kvm_freeprocs(kvm_t *kd)
684 {
685 
686 	free(kd->procbase);
687 	kd->procbase = NULL;
688 }
689 
690 void *
691 _kvm_realloc(kvm_t *kd, void *p, size_t n)
692 {
693 	void *np;
694 
695 	np = reallocf(p, n);
696 	if (np == NULL)
697 		_kvm_err(kd, kd->program, "out of memory");
698 	return (np);
699 }
700 
701 /*
702  * Get the command args or environment.
703  */
704 static char **
705 kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
706 {
707 	int oid[4];
708 	int i;
709 	size_t bufsz;
710 	static int buflen;
711 	static char *buf, *p;
712 	static char **bufp;
713 	static int argc;
714 	char **nbufp;
715 
716 	if (!ISALIVE(kd)) {
717 		_kvm_err(kd, kd->program,
718 		    "cannot read user space from dead kernel");
719 		return (NULL);
720 	}
721 
722 	if (nchr == 0 || nchr > ARG_MAX)
723 		nchr = ARG_MAX;
724 	if (buflen == 0) {
725 		buf = malloc(nchr);
726 		if (buf == NULL) {
727 			_kvm_err(kd, kd->program, "cannot allocate memory");
728 			return (NULL);
729 		}
730 		argc = 32;
731 		bufp = malloc(sizeof(char *) * argc);
732 		if (bufp == NULL) {
733 			free(buf);
734 			buf = NULL;
735 			_kvm_err(kd, kd->program, "cannot allocate memory");
736 			return (NULL);
737 		}
738 		buflen = nchr;
739 	} else if (nchr > buflen) {
740 		p = realloc(buf, nchr);
741 		if (p != NULL) {
742 			buf = p;
743 			buflen = nchr;
744 		}
745 	}
746 	oid[0] = CTL_KERN;
747 	oid[1] = KERN_PROC;
748 	oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
749 	oid[3] = kp->ki_pid;
750 	bufsz = buflen;
751 	if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
752 		/*
753 		 * If the supplied buf is too short to hold the requested
754 		 * value the sysctl returns with ENOMEM. The buf is filled
755 		 * with the truncated value and the returned bufsz is equal
756 		 * to the requested len.
757 		 */
758 		if (errno != ENOMEM || bufsz != (size_t)buflen)
759 			return (NULL);
760 		buf[bufsz - 1] = '\0';
761 		errno = 0;
762 	} else if (bufsz == 0)
763 		return (NULL);
764 	i = 0;
765 	p = buf;
766 	do {
767 		bufp[i++] = p;
768 		p += strlen(p) + 1;
769 		if (i >= argc) {
770 			argc += argc;
771 			nbufp = realloc(bufp, sizeof(char *) * argc);
772 			if (nbufp == NULL)
773 				return (NULL);
774 			bufp = nbufp;
775 		}
776 	} while (p < buf + bufsz);
777 	bufp[i++] = 0;
778 	return (bufp);
779 }
780 
781 char **
782 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
783 {
784 	return (kvm_argv(kd, kp, 0, nchr));
785 }
786 
787 char **
788 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
789 {
790 	return (kvm_argv(kd, kp, 1, nchr));
791 }
792