xref: /freebsd/lib/libkvm/kvm_proc.c (revision f0cfa1b168014f56c02b83e5f28412cc5f78d117)
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 #if 0
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
39 #endif /* LIBC_SCCS and not lint */
40 #endif
41 
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 /*
46  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
47  * users of this code, so we've factored it out into a separate module.
48  * Thus, we keep this grunge out of the other kvm applications (i.e.,
49  * most other applications are interested only in open/close/read/nlist).
50  */
51 
52 #include <sys/param.h>
53 #define	_WANT_UCRED	/* make ucred.h give us 'struct ucred' */
54 #include <sys/ucred.h>
55 #include <sys/queue.h>
56 #include <sys/_lock.h>
57 #include <sys/_mutex.h>
58 #include <sys/_task.h>
59 #include <sys/cpuset.h>
60 #include <sys/user.h>
61 #include <sys/proc.h>
62 #define	_WANT_PRISON	/* make jail.h give us 'struct prison' */
63 #include <sys/jail.h>
64 #include <sys/exec.h>
65 #include <sys/stat.h>
66 #include <sys/sysent.h>
67 #include <sys/ioctl.h>
68 #include <sys/tty.h>
69 #include <sys/file.h>
70 #include <sys/conf.h>
71 #define	_WANT_KW_EXITCODE
72 #include <sys/wait.h>
73 #include <stdio.h>
74 #include <stdlib.h>
75 #include <unistd.h>
76 #include <nlist.h>
77 #include <kvm.h>
78 
79 #include <sys/sysctl.h>
80 
81 #include <limits.h>
82 #include <memory.h>
83 #include <paths.h>
84 
85 #include "kvm_private.h"
86 
87 #define KREAD(kd, addr, obj) \
88 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
89 
90 static int ticks;
91 static int hz;
92 static uint64_t cpu_tick_frequency;
93 
94 /*
95  * From sys/kern/kern_tc.c. Depends on cpu_tick_frequency, which is
96  * read/initialized before this function is ever called.
97  */
98 static uint64_t
99 cputick2usec(uint64_t tick)
100 {
101 
102 	if (cpu_tick_frequency == 0)
103 		return (0);
104 	if (tick > 18446744073709551)		/* floor(2^64 / 1000) */
105 		return (tick / (cpu_tick_frequency / 1000000));
106 	else if (tick > 18446744073709)	/* floor(2^64 / 1000000) */
107 		return ((tick * 1000) / (cpu_tick_frequency / 1000));
108 	else
109 		return ((tick * 1000000) / cpu_tick_frequency);
110 }
111 
112 /*
113  * Read proc's from memory file into buffer bp, which has space to hold
114  * at most maxcnt procs.
115  */
116 static int
117 kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
118     struct kinfo_proc *bp, int maxcnt)
119 {
120 	int cnt = 0;
121 	struct kinfo_proc kinfo_proc, *kp;
122 	struct pgrp pgrp;
123 	struct session sess;
124 	struct cdev t_cdev;
125 	struct tty tty;
126 	struct vmspace vmspace;
127 	struct sigacts sigacts;
128 #if 0
129 	struct pstats pstats;
130 #endif
131 	struct ucred ucred;
132 	struct prison pr;
133 	struct thread mtd;
134 	struct proc proc;
135 	struct proc pproc;
136 	struct sysentvec sysent;
137 	char svname[KI_EMULNAMELEN];
138 
139 	kp = &kinfo_proc;
140 	kp->ki_structsize = sizeof(kinfo_proc);
141 	/*
142 	 * Loop on the processes. this is completely broken because we need to be
143 	 * able to loop on the threads and merge the ones that are the same process some how.
144 	 */
145 	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
146 		memset(kp, 0, sizeof *kp);
147 		if (KREAD(kd, (u_long)p, &proc)) {
148 			_kvm_err(kd, kd->program, "can't read proc at %p", p);
149 			return (-1);
150 		}
151 		if (proc.p_state == PRS_NEW)
152 			continue;
153 		if (proc.p_state != PRS_ZOMBIE) {
154 			if (KREAD(kd, (u_long)TAILQ_FIRST(&proc.p_threads),
155 			    &mtd)) {
156 				_kvm_err(kd, kd->program,
157 				    "can't read thread at %p",
158 				    TAILQ_FIRST(&proc.p_threads));
159 				return (-1);
160 			}
161 		}
162 		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
163 			kp->ki_ruid = ucred.cr_ruid;
164 			kp->ki_svuid = ucred.cr_svuid;
165 			kp->ki_rgid = ucred.cr_rgid;
166 			kp->ki_svgid = ucred.cr_svgid;
167 			kp->ki_cr_flags = ucred.cr_flags;
168 			if (ucred.cr_ngroups > KI_NGROUPS) {
169 				kp->ki_ngroups = KI_NGROUPS;
170 				kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
171 			} else
172 				kp->ki_ngroups = ucred.cr_ngroups;
173 			kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups,
174 			    kp->ki_ngroups * sizeof(gid_t));
175 			kp->ki_uid = ucred.cr_uid;
176 			if (ucred.cr_prison != NULL) {
177 				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
178 					_kvm_err(kd, kd->program,
179 					    "can't read prison at %p",
180 					    ucred.cr_prison);
181 					return (-1);
182 				}
183 				kp->ki_jid = pr.pr_id;
184 			}
185 		}
186 
187 		switch(what & ~KERN_PROC_INC_THREAD) {
188 
189 		case KERN_PROC_GID:
190 			if (kp->ki_groups[0] != (gid_t)arg)
191 				continue;
192 			break;
193 
194 		case KERN_PROC_PID:
195 			if (proc.p_pid != (pid_t)arg)
196 				continue;
197 			break;
198 
199 		case KERN_PROC_RGID:
200 			if (kp->ki_rgid != (gid_t)arg)
201 				continue;
202 			break;
203 
204 		case KERN_PROC_UID:
205 			if (kp->ki_uid != (uid_t)arg)
206 				continue;
207 			break;
208 
209 		case KERN_PROC_RUID:
210 			if (kp->ki_ruid != (uid_t)arg)
211 				continue;
212 			break;
213 		}
214 		/*
215 		 * We're going to add another proc to the set.  If this
216 		 * will overflow the buffer, assume the reason is because
217 		 * nprocs (or the proc list) is corrupt and declare an error.
218 		 */
219 		if (cnt >= maxcnt) {
220 			_kvm_err(kd, kd->program, "nprocs corrupt");
221 			return (-1);
222 		}
223 		/*
224 		 * gather kinfo_proc
225 		 */
226 		kp->ki_paddr = p;
227 		kp->ki_addr = 0;	/* XXX uarea */
228 		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
229 		kp->ki_args = proc.p_args;
230 		kp->ki_tracep = proc.p_tracevp;
231 		kp->ki_textvp = proc.p_textvp;
232 		kp->ki_fd = proc.p_fd;
233 		kp->ki_vmspace = proc.p_vmspace;
234 		if (proc.p_sigacts != NULL) {
235 			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
236 				_kvm_err(kd, kd->program,
237 				    "can't read sigacts at %p", proc.p_sigacts);
238 				return (-1);
239 			}
240 			kp->ki_sigignore = sigacts.ps_sigignore;
241 			kp->ki_sigcatch = sigacts.ps_sigcatch;
242 		}
243 #if 0
244 		if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
245 			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
246 				_kvm_err(kd, kd->program,
247 				    "can't read stats at %x", proc.p_stats);
248 				return (-1);
249 			}
250 			kp->ki_start = pstats.p_start;
251 
252 			/*
253 			 * XXX: The times here are probably zero and need
254 			 * to be calculated from the raw data in p_rux and
255 			 * p_crux.
256 			 */
257 			kp->ki_rusage = pstats.p_ru;
258 			kp->ki_childstime = pstats.p_cru.ru_stime;
259 			kp->ki_childutime = pstats.p_cru.ru_utime;
260 			/* Some callers want child-times in a single value */
261 			timeradd(&kp->ki_childstime, &kp->ki_childutime,
262 			    &kp->ki_childtime);
263 		}
264 #endif
265 		if (proc.p_oppid)
266 			kp->ki_ppid = proc.p_oppid;
267 		else if (proc.p_pptr) {
268 			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
269 				_kvm_err(kd, kd->program,
270 				    "can't read pproc at %p", proc.p_pptr);
271 				return (-1);
272 			}
273 			kp->ki_ppid = pproc.p_pid;
274 		} else
275 			kp->ki_ppid = 0;
276 		if (proc.p_pgrp == NULL)
277 			goto nopgrp;
278 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
279 			_kvm_err(kd, kd->program, "can't read pgrp at %p",
280 				 proc.p_pgrp);
281 			return (-1);
282 		}
283 		kp->ki_pgid = pgrp.pg_id;
284 		kp->ki_jobc = pgrp.pg_jobc;
285 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
286 			_kvm_err(kd, kd->program, "can't read session at %p",
287 				pgrp.pg_session);
288 			return (-1);
289 		}
290 		kp->ki_sid = sess.s_sid;
291 		(void)memcpy(kp->ki_login, sess.s_login,
292 						sizeof(kp->ki_login));
293 		kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
294 		if (sess.s_leader == p)
295 			kp->ki_kiflag |= KI_SLEADER;
296 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
297 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
298 				_kvm_err(kd, kd->program,
299 					 "can't read tty at %p", sess.s_ttyp);
300 				return (-1);
301 			}
302 			if (tty.t_dev != NULL) {
303 				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
304 					_kvm_err(kd, kd->program,
305 						 "can't read cdev at %p",
306 						tty.t_dev);
307 					return (-1);
308 				}
309 #if 0
310 				kp->ki_tdev = t_cdev.si_udev;
311 #else
312 				kp->ki_tdev = NODEV;
313 #endif
314 			}
315 			if (tty.t_pgrp != NULL) {
316 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
317 					_kvm_err(kd, kd->program,
318 						 "can't read tpgrp at %p",
319 						tty.t_pgrp);
320 					return (-1);
321 				}
322 				kp->ki_tpgid = pgrp.pg_id;
323 			} else
324 				kp->ki_tpgid = -1;
325 			if (tty.t_session != NULL) {
326 				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
327 					_kvm_err(kd, kd->program,
328 					    "can't read session at %p",
329 					    tty.t_session);
330 					return (-1);
331 				}
332 				kp->ki_tsid = sess.s_sid;
333 			}
334 		} else {
335 nopgrp:
336 			kp->ki_tdev = NODEV;
337 		}
338 		if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
339 			(void)kvm_read(kd, (u_long)mtd.td_wmesg,
340 			    kp->ki_wmesg, WMESGLEN);
341 
342 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
343 		    (char *)&vmspace, sizeof(vmspace));
344 		kp->ki_size = vmspace.vm_map.size;
345 		/*
346 		 * Approximate the kernel's method of calculating
347 		 * this field.
348 		 */
349 #define		pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
350 		kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap);
351 		kp->ki_swrss = vmspace.vm_swrss;
352 		kp->ki_tsize = vmspace.vm_tsize;
353 		kp->ki_dsize = vmspace.vm_dsize;
354 		kp->ki_ssize = vmspace.vm_ssize;
355 
356 		switch (what & ~KERN_PROC_INC_THREAD) {
357 
358 		case KERN_PROC_PGRP:
359 			if (kp->ki_pgid != (pid_t)arg)
360 				continue;
361 			break;
362 
363 		case KERN_PROC_SESSION:
364 			if (kp->ki_sid != (pid_t)arg)
365 				continue;
366 			break;
367 
368 		case KERN_PROC_TTY:
369 			if ((proc.p_flag & P_CONTROLT) == 0 ||
370 			     kp->ki_tdev != (dev_t)arg)
371 				continue;
372 			break;
373 		}
374 		if (proc.p_comm[0] != 0)
375 			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
376 		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
377 		    sizeof(sysent));
378 		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
379 		    sizeof(svname));
380 		if (svname[0] != 0)
381 			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
382 		if ((proc.p_state != PRS_ZOMBIE) &&
383 		    (mtd.td_blocked != 0)) {
384 			kp->ki_kiflag |= KI_LOCKBLOCK;
385 			if (mtd.td_lockname)
386 				(void)kvm_read(kd,
387 				    (u_long)mtd.td_lockname,
388 				    kp->ki_lockname, LOCKNAMELEN);
389 			kp->ki_lockname[LOCKNAMELEN] = 0;
390 		}
391 		kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
392 		kp->ki_pid = proc.p_pid;
393 		kp->ki_siglist = proc.p_siglist;
394 		SIGSETOR(kp->ki_siglist, mtd.td_siglist);
395 		kp->ki_sigmask = mtd.td_sigmask;
396 		kp->ki_xstat = KW_EXITCODE(proc.p_xexit, proc.p_xsig);
397 		kp->ki_acflag = proc.p_acflag;
398 		kp->ki_lock = proc.p_lock;
399 		if (proc.p_state != PRS_ZOMBIE) {
400 			kp->ki_swtime = (ticks - proc.p_swtick) / hz;
401 			kp->ki_flag = proc.p_flag;
402 			kp->ki_sflag = 0;
403 			kp->ki_nice = proc.p_nice;
404 			kp->ki_traceflag = proc.p_traceflag;
405 			if (proc.p_state == PRS_NORMAL) {
406 				if (TD_ON_RUNQ(&mtd) ||
407 				    TD_CAN_RUN(&mtd) ||
408 				    TD_IS_RUNNING(&mtd)) {
409 					kp->ki_stat = SRUN;
410 				} else if (mtd.td_state ==
411 				    TDS_INHIBITED) {
412 					if (P_SHOULDSTOP(&proc)) {
413 						kp->ki_stat = SSTOP;
414 					} else if (
415 					    TD_IS_SLEEPING(&mtd)) {
416 						kp->ki_stat = SSLEEP;
417 					} else if (TD_ON_LOCK(&mtd)) {
418 						kp->ki_stat = SLOCK;
419 					} else {
420 						kp->ki_stat = SWAIT;
421 					}
422 				}
423 			} else {
424 				kp->ki_stat = SIDL;
425 			}
426 			/* Stuff from the thread */
427 			kp->ki_pri.pri_level = mtd.td_priority;
428 			kp->ki_pri.pri_native = mtd.td_base_pri;
429 			kp->ki_lastcpu = mtd.td_lastcpu;
430 			kp->ki_wchan = mtd.td_wchan;
431 			kp->ki_oncpu = mtd.td_oncpu;
432 			if (mtd.td_name[0] != '\0')
433 				strlcpy(kp->ki_tdname, mtd.td_name, sizeof(kp->ki_tdname));
434 			kp->ki_pctcpu = 0;
435 			kp->ki_rqindex = 0;
436 
437 			/*
438 			 * Note: legacy fields; wraps at NO_CPU_OLD or the
439 			 * old max CPU value as appropriate
440 			 */
441 			if (mtd.td_lastcpu == NOCPU)
442 				kp->ki_lastcpu_old = NOCPU_OLD;
443 			else if (mtd.td_lastcpu > MAXCPU_OLD)
444 				kp->ki_lastcpu_old = MAXCPU_OLD;
445 			else
446 				kp->ki_lastcpu_old = mtd.td_lastcpu;
447 
448 			if (mtd.td_oncpu == NOCPU)
449 				kp->ki_oncpu_old = NOCPU_OLD;
450 			else if (mtd.td_oncpu > MAXCPU_OLD)
451 				kp->ki_oncpu_old = MAXCPU_OLD;
452 			else
453 				kp->ki_oncpu_old = mtd.td_oncpu;
454 		} else {
455 			kp->ki_stat = SZOMB;
456 		}
457 		kp->ki_tdev_freebsd11 = kp->ki_tdev; /* truncate */
458 		bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
459 		++bp;
460 		++cnt;
461 	}
462 	return (cnt);
463 }
464 
465 /*
466  * Build proc info array by reading in proc list from a crash dump.
467  * Return number of procs read.  maxcnt is the max we will read.
468  */
469 static int
470 kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
471     u_long a_zombproc, int maxcnt)
472 {
473 	struct kinfo_proc *bp = kd->procbase;
474 	int acnt, zcnt;
475 	struct proc *p;
476 
477 	if (KREAD(kd, a_allproc, &p)) {
478 		_kvm_err(kd, kd->program, "cannot read allproc");
479 		return (-1);
480 	}
481 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
482 	if (acnt < 0)
483 		return (acnt);
484 
485 	if (KREAD(kd, a_zombproc, &p)) {
486 		_kvm_err(kd, kd->program, "cannot read zombproc");
487 		return (-1);
488 	}
489 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
490 	if (zcnt < 0)
491 		zcnt = 0;
492 
493 	return (acnt + zcnt);
494 }
495 
496 struct kinfo_proc *
497 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
498 {
499 	int mib[4], st, nprocs;
500 	size_t size, osize;
501 	int temp_op;
502 
503 	if (kd->procbase != 0) {
504 		free((void *)kd->procbase);
505 		/*
506 		 * Clear this pointer in case this call fails.  Otherwise,
507 		 * kvm_close() will free it again.
508 		 */
509 		kd->procbase = 0;
510 	}
511 	if (ISALIVE(kd)) {
512 		size = 0;
513 		mib[0] = CTL_KERN;
514 		mib[1] = KERN_PROC;
515 		mib[2] = op;
516 		mib[3] = arg;
517 		temp_op = op & ~KERN_PROC_INC_THREAD;
518 		st = sysctl(mib,
519 		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
520 		    3 : 4, NULL, &size, NULL, 0);
521 		if (st == -1) {
522 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
523 			return (0);
524 		}
525 		/*
526 		 * We can't continue with a size of 0 because we pass
527 		 * it to realloc() (via _kvm_realloc()), and passing 0
528 		 * to realloc() results in undefined behavior.
529 		 */
530 		if (size == 0) {
531 			/*
532 			 * XXX: We should probably return an invalid,
533 			 * but non-NULL, pointer here so any client
534 			 * program trying to dereference it will
535 			 * crash.  However, _kvm_freeprocs() calls
536 			 * free() on kd->procbase if it isn't NULL,
537 			 * and free()'ing a junk pointer isn't good.
538 			 * Then again, _kvm_freeprocs() isn't used
539 			 * anywhere . . .
540 			 */
541 			kd->procbase = _kvm_malloc(kd, 1);
542 			goto liveout;
543 		}
544 		do {
545 			size += size / 10;
546 			kd->procbase = (struct kinfo_proc *)
547 			    _kvm_realloc(kd, kd->procbase, size);
548 			if (kd->procbase == NULL)
549 				return (0);
550 			osize = size;
551 			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
552 			    temp_op == KERN_PROC_PROC ? 3 : 4,
553 			    kd->procbase, &size, NULL, 0);
554 		} while (st == -1 && errno == ENOMEM && size == osize);
555 		if (st == -1) {
556 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
557 			return (0);
558 		}
559 		/*
560 		 * We have to check the size again because sysctl()
561 		 * may "round up" oldlenp if oldp is NULL; hence it
562 		 * might've told us that there was data to get when
563 		 * there really isn't any.
564 		 */
565 		if (size > 0 &&
566 		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
567 			_kvm_err(kd, kd->program,
568 			    "kinfo_proc size mismatch (expected %zu, got %d)",
569 			    sizeof(struct kinfo_proc),
570 			    kd->procbase->ki_structsize);
571 			return (0);
572 		}
573 liveout:
574 		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
575 	} else {
576 		struct nlist nl[7], *p;
577 
578 		nl[0].n_name = "_nprocs";
579 		nl[1].n_name = "_allproc";
580 		nl[2].n_name = "_zombproc";
581 		nl[3].n_name = "_ticks";
582 		nl[4].n_name = "_hz";
583 		nl[5].n_name = "_cpu_tick_frequency";
584 		nl[6].n_name = 0;
585 
586 		if (!kd->arch->ka_native(kd)) {
587 			_kvm_err(kd, kd->program,
588 			    "cannot read procs from non-native core");
589 			return (0);
590 		}
591 
592 		if (kvm_nlist(kd, nl) != 0) {
593 			for (p = nl; p->n_type != 0; ++p)
594 				;
595 			_kvm_err(kd, kd->program,
596 				 "%s: no such symbol", p->n_name);
597 			return (0);
598 		}
599 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
600 			_kvm_err(kd, kd->program, "can't read nprocs");
601 			return (0);
602 		}
603 		if (KREAD(kd, nl[3].n_value, &ticks)) {
604 			_kvm_err(kd, kd->program, "can't read ticks");
605 			return (0);
606 		}
607 		if (KREAD(kd, nl[4].n_value, &hz)) {
608 			_kvm_err(kd, kd->program, "can't read hz");
609 			return (0);
610 		}
611 		if (KREAD(kd, nl[5].n_value, &cpu_tick_frequency)) {
612 			_kvm_err(kd, kd->program,
613 			    "can't read cpu_tick_frequency");
614 			return (0);
615 		}
616 		size = nprocs * sizeof(struct kinfo_proc);
617 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
618 		if (kd->procbase == NULL)
619 			return (0);
620 
621 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
622 				      nl[2].n_value, nprocs);
623 		if (nprocs <= 0) {
624 			_kvm_freeprocs(kd);
625 			nprocs = 0;
626 		}
627 #ifdef notdef
628 		else {
629 			size = nprocs * sizeof(struct kinfo_proc);
630 			kd->procbase = realloc(kd->procbase, size);
631 		}
632 #endif
633 	}
634 	*cnt = nprocs;
635 	return (kd->procbase);
636 }
637 
638 void
639 _kvm_freeprocs(kvm_t *kd)
640 {
641 
642 	free(kd->procbase);
643 	kd->procbase = NULL;
644 }
645 
646 void *
647 _kvm_realloc(kvm_t *kd, void *p, size_t n)
648 {
649 	void *np;
650 
651 	np = reallocf(p, n);
652 	if (np == NULL)
653 		_kvm_err(kd, kd->program, "out of memory");
654 	return (np);
655 }
656 
657 /*
658  * Get the command args or environment.
659  */
660 static char **
661 kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
662 {
663 	int oid[4];
664 	int i;
665 	size_t bufsz;
666 	static int buflen;
667 	static char *buf, *p;
668 	static char **bufp;
669 	static int argc;
670 	char **nbufp;
671 
672 	if (!ISALIVE(kd)) {
673 		_kvm_err(kd, kd->program,
674 		    "cannot read user space from dead kernel");
675 		return (NULL);
676 	}
677 
678 	if (nchr == 0 || nchr > ARG_MAX)
679 		nchr = ARG_MAX;
680 	if (buflen == 0) {
681 		buf = malloc(nchr);
682 		if (buf == NULL) {
683 			_kvm_err(kd, kd->program, "cannot allocate memory");
684 			return (NULL);
685 		}
686 		argc = 32;
687 		bufp = malloc(sizeof(char *) * argc);
688 		if (bufp == NULL) {
689 			free(buf);
690 			buf = NULL;
691 			_kvm_err(kd, kd->program, "cannot allocate memory");
692 			return (NULL);
693 		}
694 		buflen = nchr;
695 	} else if (nchr > buflen) {
696 		p = realloc(buf, nchr);
697 		if (p != NULL) {
698 			buf = p;
699 			buflen = nchr;
700 		}
701 	}
702 	oid[0] = CTL_KERN;
703 	oid[1] = KERN_PROC;
704 	oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
705 	oid[3] = kp->ki_pid;
706 	bufsz = buflen;
707 	if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
708 		/*
709 		 * If the supplied buf is too short to hold the requested
710 		 * value the sysctl returns with ENOMEM. The buf is filled
711 		 * with the truncated value and the returned bufsz is equal
712 		 * to the requested len.
713 		 */
714 		if (errno != ENOMEM || bufsz != (size_t)buflen)
715 			return (NULL);
716 		buf[bufsz - 1] = '\0';
717 		errno = 0;
718 	} else if (bufsz == 0)
719 		return (NULL);
720 	i = 0;
721 	p = buf;
722 	do {
723 		bufp[i++] = p;
724 		p += strlen(p) + 1;
725 		if (i >= argc) {
726 			argc += argc;
727 			nbufp = realloc(bufp, sizeof(char *) * argc);
728 			if (nbufp == NULL)
729 				return (NULL);
730 			bufp = nbufp;
731 		}
732 	} while (p < buf + bufsz);
733 	bufp[i++] = 0;
734 	return (bufp);
735 }
736 
737 char **
738 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
739 {
740 	return (kvm_argv(kd, kp, 0, nchr));
741 }
742 
743 char **
744 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
745 {
746 	return (kvm_argv(kd, kp, 1, nchr));
747 }
748