xref: /freebsd/lib/libkvm/kvm_proc.c (revision 40a8ac8f62b535d30349faf28cf47106b7041b83)
1 /*-
2  * Copyright (c) 1989, 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software developed by the Computer Systems
6  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
7  * BG 91-66 and contributed to Berkeley.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if 0
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
37 #endif /* LIBC_SCCS and not lint */
38 #endif
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 /*
44  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
45  * users of this code, so we've factored it out into a separate module.
46  * Thus, we keep this grunge out of the other kvm applications (i.e.,
47  * most other applications are interested only in open/close/read/nlist).
48  */
49 
50 #include <sys/param.h>
51 #define	_WANT_UCRED	/* make ucred.h give us 'struct ucred' */
52 #include <sys/ucred.h>
53 #include <sys/queue.h>
54 #include <sys/_lock.h>
55 #include <sys/_mutex.h>
56 #include <sys/_task.h>
57 #include <sys/cpuset.h>
58 #include <sys/user.h>
59 #include <sys/proc.h>
60 #define	_WANT_PRISON	/* make jail.h give us 'struct prison' */
61 #include <sys/jail.h>
62 #include <sys/exec.h>
63 #include <sys/stat.h>
64 #include <sys/sysent.h>
65 #include <sys/ioctl.h>
66 #include <sys/tty.h>
67 #include <sys/file.h>
68 #include <sys/conf.h>
69 #include <stdio.h>
70 #include <stdlib.h>
71 #include <unistd.h>
72 #include <nlist.h>
73 #include <kvm.h>
74 
75 #include <sys/sysctl.h>
76 
77 #include <limits.h>
78 #include <memory.h>
79 #include <paths.h>
80 
81 #include "kvm_private.h"
82 
83 #define KREAD(kd, addr, obj) \
84 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
85 
86 static int ticks;
87 static int hz;
88 static uint64_t cpu_tick_frequency;
89 
90 /*
91  * From sys/kern/kern_tc.c. Depends on cpu_tick_frequency, which is
92  * read/initialized before this function is ever called.
93  */
94 static uint64_t
95 cputick2usec(uint64_t tick)
96 {
97 
98 	if (cpu_tick_frequency == 0)
99 		return (0);
100 	if (tick > 18446744073709551)		/* floor(2^64 / 1000) */
101 		return (tick / (cpu_tick_frequency / 1000000));
102 	else if (tick > 18446744073709)	/* floor(2^64 / 1000000) */
103 		return ((tick * 1000) / (cpu_tick_frequency / 1000));
104 	else
105 		return ((tick * 1000000) / cpu_tick_frequency);
106 }
107 
108 /*
109  * Read proc's from memory file into buffer bp, which has space to hold
110  * at most maxcnt procs.
111  */
112 static int
113 kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
114     struct kinfo_proc *bp, int maxcnt)
115 {
116 	int cnt = 0;
117 	struct kinfo_proc kinfo_proc, *kp;
118 	struct pgrp pgrp;
119 	struct session sess;
120 	struct cdev t_cdev;
121 	struct tty tty;
122 	struct vmspace vmspace;
123 	struct sigacts sigacts;
124 #if 0
125 	struct pstats pstats;
126 #endif
127 	struct ucred ucred;
128 	struct prison pr;
129 	struct thread mtd;
130 	struct proc proc;
131 	struct proc pproc;
132 	struct sysentvec sysent;
133 	char svname[KI_EMULNAMELEN];
134 
135 	kp = &kinfo_proc;
136 	kp->ki_structsize = sizeof(kinfo_proc);
137 	/*
138 	 * Loop on the processes. this is completely broken because we need to be
139 	 * able to loop on the threads and merge the ones that are the same process some how.
140 	 */
141 	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
142 		memset(kp, 0, sizeof *kp);
143 		if (KREAD(kd, (u_long)p, &proc)) {
144 			_kvm_err(kd, kd->program, "can't read proc at %p", p);
145 			return (-1);
146 		}
147 		if (proc.p_state == PRS_NEW)
148 			continue;
149 		if (proc.p_state != PRS_ZOMBIE) {
150 			if (KREAD(kd, (u_long)TAILQ_FIRST(&proc.p_threads),
151 			    &mtd)) {
152 				_kvm_err(kd, kd->program,
153 				    "can't read thread at %p",
154 				    TAILQ_FIRST(&proc.p_threads));
155 				return (-1);
156 			}
157 		}
158 		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
159 			kp->ki_ruid = ucred.cr_ruid;
160 			kp->ki_svuid = ucred.cr_svuid;
161 			kp->ki_rgid = ucred.cr_rgid;
162 			kp->ki_svgid = ucred.cr_svgid;
163 			kp->ki_cr_flags = ucred.cr_flags;
164 			if (ucred.cr_ngroups > KI_NGROUPS) {
165 				kp->ki_ngroups = KI_NGROUPS;
166 				kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
167 			} else
168 				kp->ki_ngroups = ucred.cr_ngroups;
169 			kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups,
170 			    kp->ki_ngroups * sizeof(gid_t));
171 			kp->ki_uid = ucred.cr_uid;
172 			if (ucred.cr_prison != NULL) {
173 				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
174 					_kvm_err(kd, kd->program,
175 					    "can't read prison at %p",
176 					    ucred.cr_prison);
177 					return (-1);
178 				}
179 				kp->ki_jid = pr.pr_id;
180 			}
181 		}
182 
183 		switch(what & ~KERN_PROC_INC_THREAD) {
184 
185 		case KERN_PROC_GID:
186 			if (kp->ki_groups[0] != (gid_t)arg)
187 				continue;
188 			break;
189 
190 		case KERN_PROC_PID:
191 			if (proc.p_pid != (pid_t)arg)
192 				continue;
193 			break;
194 
195 		case KERN_PROC_RGID:
196 			if (kp->ki_rgid != (gid_t)arg)
197 				continue;
198 			break;
199 
200 		case KERN_PROC_UID:
201 			if (kp->ki_uid != (uid_t)arg)
202 				continue;
203 			break;
204 
205 		case KERN_PROC_RUID:
206 			if (kp->ki_ruid != (uid_t)arg)
207 				continue;
208 			break;
209 		}
210 		/*
211 		 * We're going to add another proc to the set.  If this
212 		 * will overflow the buffer, assume the reason is because
213 		 * nprocs (or the proc list) is corrupt and declare an error.
214 		 */
215 		if (cnt >= maxcnt) {
216 			_kvm_err(kd, kd->program, "nprocs corrupt");
217 			return (-1);
218 		}
219 		/*
220 		 * gather kinfo_proc
221 		 */
222 		kp->ki_paddr = p;
223 		kp->ki_addr = 0;	/* XXX uarea */
224 		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
225 		kp->ki_args = proc.p_args;
226 		kp->ki_tracep = proc.p_tracevp;
227 		kp->ki_textvp = proc.p_textvp;
228 		kp->ki_fd = proc.p_fd;
229 		kp->ki_vmspace = proc.p_vmspace;
230 		if (proc.p_sigacts != NULL) {
231 			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
232 				_kvm_err(kd, kd->program,
233 				    "can't read sigacts at %p", proc.p_sigacts);
234 				return (-1);
235 			}
236 			kp->ki_sigignore = sigacts.ps_sigignore;
237 			kp->ki_sigcatch = sigacts.ps_sigcatch;
238 		}
239 #if 0
240 		if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
241 			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
242 				_kvm_err(kd, kd->program,
243 				    "can't read stats at %x", proc.p_stats);
244 				return (-1);
245 			}
246 			kp->ki_start = pstats.p_start;
247 
248 			/*
249 			 * XXX: The times here are probably zero and need
250 			 * to be calculated from the raw data in p_rux and
251 			 * p_crux.
252 			 */
253 			kp->ki_rusage = pstats.p_ru;
254 			kp->ki_childstime = pstats.p_cru.ru_stime;
255 			kp->ki_childutime = pstats.p_cru.ru_utime;
256 			/* Some callers want child-times in a single value */
257 			timeradd(&kp->ki_childstime, &kp->ki_childutime,
258 			    &kp->ki_childtime);
259 		}
260 #endif
261 		if (proc.p_oppid)
262 			kp->ki_ppid = proc.p_oppid;
263 		else if (proc.p_pptr) {
264 			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
265 				_kvm_err(kd, kd->program,
266 				    "can't read pproc at %p", proc.p_pptr);
267 				return (-1);
268 			}
269 			kp->ki_ppid = pproc.p_pid;
270 		} else
271 			kp->ki_ppid = 0;
272 		if (proc.p_pgrp == NULL)
273 			goto nopgrp;
274 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
275 			_kvm_err(kd, kd->program, "can't read pgrp at %p",
276 				 proc.p_pgrp);
277 			return (-1);
278 		}
279 		kp->ki_pgid = pgrp.pg_id;
280 		kp->ki_jobc = pgrp.pg_jobc;
281 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
282 			_kvm_err(kd, kd->program, "can't read session at %p",
283 				pgrp.pg_session);
284 			return (-1);
285 		}
286 		kp->ki_sid = sess.s_sid;
287 		(void)memcpy(kp->ki_login, sess.s_login,
288 						sizeof(kp->ki_login));
289 		kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
290 		if (sess.s_leader == p)
291 			kp->ki_kiflag |= KI_SLEADER;
292 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
293 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
294 				_kvm_err(kd, kd->program,
295 					 "can't read tty at %p", sess.s_ttyp);
296 				return (-1);
297 			}
298 			if (tty.t_dev != NULL) {
299 				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
300 					_kvm_err(kd, kd->program,
301 						 "can't read cdev at %p",
302 						tty.t_dev);
303 					return (-1);
304 				}
305 #if 0
306 				kp->ki_tdev = t_cdev.si_udev;
307 #else
308 				kp->ki_tdev = NODEV;
309 #endif
310 			}
311 			if (tty.t_pgrp != NULL) {
312 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
313 					_kvm_err(kd, kd->program,
314 						 "can't read tpgrp at %p",
315 						tty.t_pgrp);
316 					return (-1);
317 				}
318 				kp->ki_tpgid = pgrp.pg_id;
319 			} else
320 				kp->ki_tpgid = -1;
321 			if (tty.t_session != NULL) {
322 				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
323 					_kvm_err(kd, kd->program,
324 					    "can't read session at %p",
325 					    tty.t_session);
326 					return (-1);
327 				}
328 				kp->ki_tsid = sess.s_sid;
329 			}
330 		} else {
331 nopgrp:
332 			kp->ki_tdev = NODEV;
333 		}
334 		if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
335 			(void)kvm_read(kd, (u_long)mtd.td_wmesg,
336 			    kp->ki_wmesg, WMESGLEN);
337 
338 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
339 		    (char *)&vmspace, sizeof(vmspace));
340 		kp->ki_size = vmspace.vm_map.size;
341 		/*
342 		 * Approximate the kernel's method of calculating
343 		 * this field.
344 		 */
345 #define		pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
346 		kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap);
347 		kp->ki_swrss = vmspace.vm_swrss;
348 		kp->ki_tsize = vmspace.vm_tsize;
349 		kp->ki_dsize = vmspace.vm_dsize;
350 		kp->ki_ssize = vmspace.vm_ssize;
351 
352 		switch (what & ~KERN_PROC_INC_THREAD) {
353 
354 		case KERN_PROC_PGRP:
355 			if (kp->ki_pgid != (pid_t)arg)
356 				continue;
357 			break;
358 
359 		case KERN_PROC_SESSION:
360 			if (kp->ki_sid != (pid_t)arg)
361 				continue;
362 			break;
363 
364 		case KERN_PROC_TTY:
365 			if ((proc.p_flag & P_CONTROLT) == 0 ||
366 			     kp->ki_tdev != (dev_t)arg)
367 				continue;
368 			break;
369 		}
370 		if (proc.p_comm[0] != 0)
371 			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
372 		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
373 		    sizeof(sysent));
374 		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
375 		    sizeof(svname));
376 		if (svname[0] != 0)
377 			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
378 		if ((proc.p_state != PRS_ZOMBIE) &&
379 		    (mtd.td_blocked != 0)) {
380 			kp->ki_kiflag |= KI_LOCKBLOCK;
381 			if (mtd.td_lockname)
382 				(void)kvm_read(kd,
383 				    (u_long)mtd.td_lockname,
384 				    kp->ki_lockname, LOCKNAMELEN);
385 			kp->ki_lockname[LOCKNAMELEN] = 0;
386 		}
387 		kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
388 		kp->ki_pid = proc.p_pid;
389 		kp->ki_siglist = proc.p_siglist;
390 		SIGSETOR(kp->ki_siglist, mtd.td_siglist);
391 		kp->ki_sigmask = mtd.td_sigmask;
392 		kp->ki_xstat = proc.p_xstat;
393 		kp->ki_acflag = proc.p_acflag;
394 		kp->ki_lock = proc.p_lock;
395 		if (proc.p_state != PRS_ZOMBIE) {
396 			kp->ki_swtime = (ticks - proc.p_swtick) / hz;
397 			kp->ki_flag = proc.p_flag;
398 			kp->ki_sflag = 0;
399 			kp->ki_nice = proc.p_nice;
400 			kp->ki_traceflag = proc.p_traceflag;
401 			if (proc.p_state == PRS_NORMAL) {
402 				if (TD_ON_RUNQ(&mtd) ||
403 				    TD_CAN_RUN(&mtd) ||
404 				    TD_IS_RUNNING(&mtd)) {
405 					kp->ki_stat = SRUN;
406 				} else if (mtd.td_state ==
407 				    TDS_INHIBITED) {
408 					if (P_SHOULDSTOP(&proc)) {
409 						kp->ki_stat = SSTOP;
410 					} else if (
411 					    TD_IS_SLEEPING(&mtd)) {
412 						kp->ki_stat = SSLEEP;
413 					} else if (TD_ON_LOCK(&mtd)) {
414 						kp->ki_stat = SLOCK;
415 					} else {
416 						kp->ki_stat = SWAIT;
417 					}
418 				}
419 			} else {
420 				kp->ki_stat = SIDL;
421 			}
422 			/* Stuff from the thread */
423 			kp->ki_pri.pri_level = mtd.td_priority;
424 			kp->ki_pri.pri_native = mtd.td_base_pri;
425 			kp->ki_lastcpu = mtd.td_lastcpu;
426 			kp->ki_wchan = mtd.td_wchan;
427 			if (mtd.td_name[0] != 0)
428 				strlcpy(kp->ki_tdname, mtd.td_name, MAXCOMLEN);
429 			kp->ki_oncpu = mtd.td_oncpu;
430 			if (mtd.td_name[0] != '\0')
431 				strlcpy(kp->ki_tdname, mtd.td_name, sizeof(kp->ki_tdname));
432 			kp->ki_pctcpu = 0;
433 			kp->ki_rqindex = 0;
434 		} else {
435 			kp->ki_stat = SZOMB;
436 		}
437 		bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
438 		++bp;
439 		++cnt;
440 	}
441 	return (cnt);
442 }
443 
444 /*
445  * Build proc info array by reading in proc list from a crash dump.
446  * Return number of procs read.  maxcnt is the max we will read.
447  */
448 static int
449 kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
450     u_long a_zombproc, int maxcnt)
451 {
452 	struct kinfo_proc *bp = kd->procbase;
453 	int acnt, zcnt;
454 	struct proc *p;
455 
456 	if (KREAD(kd, a_allproc, &p)) {
457 		_kvm_err(kd, kd->program, "cannot read allproc");
458 		return (-1);
459 	}
460 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
461 	if (acnt < 0)
462 		return (acnt);
463 
464 	if (KREAD(kd, a_zombproc, &p)) {
465 		_kvm_err(kd, kd->program, "cannot read zombproc");
466 		return (-1);
467 	}
468 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
469 	if (zcnt < 0)
470 		zcnt = 0;
471 
472 	return (acnt + zcnt);
473 }
474 
475 struct kinfo_proc *
476 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
477 {
478 	int mib[4], st, nprocs;
479 	size_t size, osize;
480 	int temp_op;
481 
482 	if (kd->procbase != 0) {
483 		free((void *)kd->procbase);
484 		/*
485 		 * Clear this pointer in case this call fails.  Otherwise,
486 		 * kvm_close() will free it again.
487 		 */
488 		kd->procbase = 0;
489 	}
490 	if (ISALIVE(kd)) {
491 		size = 0;
492 		mib[0] = CTL_KERN;
493 		mib[1] = KERN_PROC;
494 		mib[2] = op;
495 		mib[3] = arg;
496 		temp_op = op & ~KERN_PROC_INC_THREAD;
497 		st = sysctl(mib,
498 		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
499 		    3 : 4, NULL, &size, NULL, 0);
500 		if (st == -1) {
501 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
502 			return (0);
503 		}
504 		/*
505 		 * We can't continue with a size of 0 because we pass
506 		 * it to realloc() (via _kvm_realloc()), and passing 0
507 		 * to realloc() results in undefined behavior.
508 		 */
509 		if (size == 0) {
510 			/*
511 			 * XXX: We should probably return an invalid,
512 			 * but non-NULL, pointer here so any client
513 			 * program trying to dereference it will
514 			 * crash.  However, _kvm_freeprocs() calls
515 			 * free() on kd->procbase if it isn't NULL,
516 			 * and free()'ing a junk pointer isn't good.
517 			 * Then again, _kvm_freeprocs() isn't used
518 			 * anywhere . . .
519 			 */
520 			kd->procbase = _kvm_malloc(kd, 1);
521 			goto liveout;
522 		}
523 		do {
524 			size += size / 10;
525 			kd->procbase = (struct kinfo_proc *)
526 			    _kvm_realloc(kd, kd->procbase, size);
527 			if (kd->procbase == 0)
528 				return (0);
529 			osize = size;
530 			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
531 			    temp_op == KERN_PROC_PROC ? 3 : 4,
532 			    kd->procbase, &size, NULL, 0);
533 		} while (st == -1 && errno == ENOMEM && size == osize);
534 		if (st == -1) {
535 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
536 			return (0);
537 		}
538 		/*
539 		 * We have to check the size again because sysctl()
540 		 * may "round up" oldlenp if oldp is NULL; hence it
541 		 * might've told us that there was data to get when
542 		 * there really isn't any.
543 		 */
544 		if (size > 0 &&
545 		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
546 			_kvm_err(kd, kd->program,
547 			    "kinfo_proc size mismatch (expected %zu, got %d)",
548 			    sizeof(struct kinfo_proc),
549 			    kd->procbase->ki_structsize);
550 			return (0);
551 		}
552 liveout:
553 		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
554 	} else {
555 		struct nlist nl[7], *p;
556 
557 		nl[0].n_name = "_nprocs";
558 		nl[1].n_name = "_allproc";
559 		nl[2].n_name = "_zombproc";
560 		nl[3].n_name = "_ticks";
561 		nl[4].n_name = "_hz";
562 		nl[5].n_name = "_cpu_tick_frequency";
563 		nl[6].n_name = 0;
564 
565 		if (kvm_nlist(kd, nl) != 0) {
566 			for (p = nl; p->n_type != 0; ++p)
567 				;
568 			_kvm_err(kd, kd->program,
569 				 "%s: no such symbol", p->n_name);
570 			return (0);
571 		}
572 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
573 			_kvm_err(kd, kd->program, "can't read nprocs");
574 			return (0);
575 		}
576 		if (KREAD(kd, nl[3].n_value, &ticks)) {
577 			_kvm_err(kd, kd->program, "can't read ticks");
578 			return (0);
579 		}
580 		if (KREAD(kd, nl[4].n_value, &hz)) {
581 			_kvm_err(kd, kd->program, "can't read hz");
582 			return (0);
583 		}
584 		if (KREAD(kd, nl[5].n_value, &cpu_tick_frequency)) {
585 			_kvm_err(kd, kd->program,
586 			    "can't read cpu_tick_frequency");
587 			return (0);
588 		}
589 		size = nprocs * sizeof(struct kinfo_proc);
590 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
591 		if (kd->procbase == 0)
592 			return (0);
593 
594 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
595 				      nl[2].n_value, nprocs);
596 		if (nprocs <= 0) {
597 			_kvm_freeprocs(kd);
598 			nprocs = 0;
599 		}
600 #ifdef notdef
601 		else {
602 			size = nprocs * sizeof(struct kinfo_proc);
603 			kd->procbase = realloc(kd->procbase, size);
604 		}
605 #endif
606 	}
607 	*cnt = nprocs;
608 	return (kd->procbase);
609 }
610 
611 void
612 _kvm_freeprocs(kvm_t *kd)
613 {
614 	if (kd->procbase) {
615 		free(kd->procbase);
616 		kd->procbase = 0;
617 	}
618 }
619 
620 void *
621 _kvm_realloc(kvm_t *kd, void *p, size_t n)
622 {
623 	void *np = (void *)realloc(p, n);
624 
625 	if (np == 0) {
626 		free(p);
627 		_kvm_err(kd, kd->program, "out of memory");
628 	}
629 	return (np);
630 }
631 
632 /*
633  * Get the command args or environment.
634  */
635 static char **
636 kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
637 {
638 	int oid[4];
639 	int i;
640 	size_t bufsz;
641 	static int buflen;
642 	static char *buf, *p;
643 	static char **bufp;
644 	static int argc;
645 
646 	if (!ISALIVE(kd)) {
647 		_kvm_err(kd, kd->program,
648 		    "cannot read user space from dead kernel");
649 		return (0);
650 	}
651 
652 	if (nchr == 0 || nchr > ARG_MAX)
653 		nchr = ARG_MAX;
654 	if (buflen == 0) {
655 		buf = malloc(nchr);
656 		if (buf == NULL) {
657 			_kvm_err(kd, kd->program, "cannot allocate memory");
658 			return (0);
659 		}
660 		buflen = nchr;
661 		argc = 32;
662 		bufp = malloc(sizeof(char *) * argc);
663 	} else if (nchr > buflen) {
664 		p = realloc(buf, nchr);
665 		if (p != NULL) {
666 			buf = p;
667 			buflen = nchr;
668 		}
669 	}
670 	oid[0] = CTL_KERN;
671 	oid[1] = KERN_PROC;
672 	oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
673 	oid[3] = kp->ki_pid;
674 	bufsz = buflen;
675 	if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
676 		/*
677 		 * If the supplied buf is too short to hold the requested
678 		 * value the sysctl returns with ENOMEM. The buf is filled
679 		 * with the truncated value and the returned bufsz is equal
680 		 * to the requested len.
681 		 */
682 		if (errno != ENOMEM || bufsz != (size_t)buflen)
683 			return (0);
684 		buf[bufsz - 1] = '\0';
685 		errno = 0;
686 	} else if (bufsz == 0) {
687 		return (0);
688 	}
689 	i = 0;
690 	p = buf;
691 	do {
692 		bufp[i++] = p;
693 		p += strlen(p) + 1;
694 		if (i >= argc) {
695 			argc += argc;
696 			bufp = realloc(bufp,
697 			    sizeof(char *) * argc);
698 		}
699 	} while (p < buf + bufsz);
700 	bufp[i++] = 0;
701 	return (bufp);
702 }
703 
704 char **
705 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
706 {
707 	return (kvm_argv(kd, kp, 0, nchr));
708 }
709 
710 char **
711 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
712 {
713 	return (kvm_argv(kd, kp, 1, nchr));
714 }
715