xref: /freebsd/lib/libkvm/kvm_proc.c (revision ae1f3df43466466a21c7da0df93ecb58a3e53d74)
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 #define	_WANT_KW_EXITCODE
70 #include <sys/wait.h>
71 #include <stdio.h>
72 #include <stdlib.h>
73 #include <unistd.h>
74 #include <nlist.h>
75 #include <kvm.h>
76 
77 #include <sys/sysctl.h>
78 
79 #include <limits.h>
80 #include <memory.h>
81 #include <paths.h>
82 
83 #include "kvm_private.h"
84 
85 #define KREAD(kd, addr, obj) \
86 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
87 
88 static int ticks;
89 static int hz;
90 static uint64_t cpu_tick_frequency;
91 
92 /*
93  * From sys/kern/kern_tc.c. Depends on cpu_tick_frequency, which is
94  * read/initialized before this function is ever called.
95  */
96 static uint64_t
97 cputick2usec(uint64_t tick)
98 {
99 
100 	if (cpu_tick_frequency == 0)
101 		return (0);
102 	if (tick > 18446744073709551)		/* floor(2^64 / 1000) */
103 		return (tick / (cpu_tick_frequency / 1000000));
104 	else if (tick > 18446744073709)	/* floor(2^64 / 1000000) */
105 		return ((tick * 1000) / (cpu_tick_frequency / 1000));
106 	else
107 		return ((tick * 1000000) / cpu_tick_frequency);
108 }
109 
110 /*
111  * Read proc's from memory file into buffer bp, which has space to hold
112  * at most maxcnt procs.
113  */
114 static int
115 kvm_proclist(kvm_t *kd, int what, int arg, struct proc *p,
116     struct kinfo_proc *bp, int maxcnt)
117 {
118 	int cnt = 0;
119 	struct kinfo_proc kinfo_proc, *kp;
120 	struct pgrp pgrp;
121 	struct session sess;
122 	struct cdev t_cdev;
123 	struct tty tty;
124 	struct vmspace vmspace;
125 	struct sigacts sigacts;
126 #if 0
127 	struct pstats pstats;
128 #endif
129 	struct ucred ucred;
130 	struct prison pr;
131 	struct thread mtd;
132 	struct proc proc;
133 	struct proc pproc;
134 	struct sysentvec sysent;
135 	char svname[KI_EMULNAMELEN];
136 
137 	kp = &kinfo_proc;
138 	kp->ki_structsize = sizeof(kinfo_proc);
139 	/*
140 	 * Loop on the processes. this is completely broken because we need to be
141 	 * able to loop on the threads and merge the ones that are the same process some how.
142 	 */
143 	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
144 		memset(kp, 0, sizeof *kp);
145 		if (KREAD(kd, (u_long)p, &proc)) {
146 			_kvm_err(kd, kd->program, "can't read proc at %p", p);
147 			return (-1);
148 		}
149 		if (proc.p_state == PRS_NEW)
150 			continue;
151 		if (proc.p_state != PRS_ZOMBIE) {
152 			if (KREAD(kd, (u_long)TAILQ_FIRST(&proc.p_threads),
153 			    &mtd)) {
154 				_kvm_err(kd, kd->program,
155 				    "can't read thread at %p",
156 				    TAILQ_FIRST(&proc.p_threads));
157 				return (-1);
158 			}
159 		}
160 		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
161 			kp->ki_ruid = ucred.cr_ruid;
162 			kp->ki_svuid = ucred.cr_svuid;
163 			kp->ki_rgid = ucred.cr_rgid;
164 			kp->ki_svgid = ucred.cr_svgid;
165 			kp->ki_cr_flags = ucred.cr_flags;
166 			if (ucred.cr_ngroups > KI_NGROUPS) {
167 				kp->ki_ngroups = KI_NGROUPS;
168 				kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
169 			} else
170 				kp->ki_ngroups = ucred.cr_ngroups;
171 			kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups,
172 			    kp->ki_ngroups * sizeof(gid_t));
173 			kp->ki_uid = ucred.cr_uid;
174 			if (ucred.cr_prison != NULL) {
175 				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
176 					_kvm_err(kd, kd->program,
177 					    "can't read prison at %p",
178 					    ucred.cr_prison);
179 					return (-1);
180 				}
181 				kp->ki_jid = pr.pr_id;
182 			}
183 		}
184 
185 		switch(what & ~KERN_PROC_INC_THREAD) {
186 
187 		case KERN_PROC_GID:
188 			if (kp->ki_groups[0] != (gid_t)arg)
189 				continue;
190 			break;
191 
192 		case KERN_PROC_PID:
193 			if (proc.p_pid != (pid_t)arg)
194 				continue;
195 			break;
196 
197 		case KERN_PROC_RGID:
198 			if (kp->ki_rgid != (gid_t)arg)
199 				continue;
200 			break;
201 
202 		case KERN_PROC_UID:
203 			if (kp->ki_uid != (uid_t)arg)
204 				continue;
205 			break;
206 
207 		case KERN_PROC_RUID:
208 			if (kp->ki_ruid != (uid_t)arg)
209 				continue;
210 			break;
211 		}
212 		/*
213 		 * We're going to add another proc to the set.  If this
214 		 * will overflow the buffer, assume the reason is because
215 		 * nprocs (or the proc list) is corrupt and declare an error.
216 		 */
217 		if (cnt >= maxcnt) {
218 			_kvm_err(kd, kd->program, "nprocs corrupt");
219 			return (-1);
220 		}
221 		/*
222 		 * gather kinfo_proc
223 		 */
224 		kp->ki_paddr = p;
225 		kp->ki_addr = 0;	/* XXX uarea */
226 		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
227 		kp->ki_args = proc.p_args;
228 		kp->ki_tracep = proc.p_tracevp;
229 		kp->ki_textvp = proc.p_textvp;
230 		kp->ki_fd = proc.p_fd;
231 		kp->ki_vmspace = proc.p_vmspace;
232 		if (proc.p_sigacts != NULL) {
233 			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
234 				_kvm_err(kd, kd->program,
235 				    "can't read sigacts at %p", proc.p_sigacts);
236 				return (-1);
237 			}
238 			kp->ki_sigignore = sigacts.ps_sigignore;
239 			kp->ki_sigcatch = sigacts.ps_sigcatch;
240 		}
241 #if 0
242 		if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
243 			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
244 				_kvm_err(kd, kd->program,
245 				    "can't read stats at %x", proc.p_stats);
246 				return (-1);
247 			}
248 			kp->ki_start = pstats.p_start;
249 
250 			/*
251 			 * XXX: The times here are probably zero and need
252 			 * to be calculated from the raw data in p_rux and
253 			 * p_crux.
254 			 */
255 			kp->ki_rusage = pstats.p_ru;
256 			kp->ki_childstime = pstats.p_cru.ru_stime;
257 			kp->ki_childutime = pstats.p_cru.ru_utime;
258 			/* Some callers want child-times in a single value */
259 			timeradd(&kp->ki_childstime, &kp->ki_childutime,
260 			    &kp->ki_childtime);
261 		}
262 #endif
263 		if (proc.p_oppid)
264 			kp->ki_ppid = proc.p_oppid;
265 		else if (proc.p_pptr) {
266 			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
267 				_kvm_err(kd, kd->program,
268 				    "can't read pproc at %p", proc.p_pptr);
269 				return (-1);
270 			}
271 			kp->ki_ppid = pproc.p_pid;
272 		} else
273 			kp->ki_ppid = 0;
274 		if (proc.p_pgrp == NULL)
275 			goto nopgrp;
276 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
277 			_kvm_err(kd, kd->program, "can't read pgrp at %p",
278 				 proc.p_pgrp);
279 			return (-1);
280 		}
281 		kp->ki_pgid = pgrp.pg_id;
282 		kp->ki_jobc = pgrp.pg_jobc;
283 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
284 			_kvm_err(kd, kd->program, "can't read session at %p",
285 				pgrp.pg_session);
286 			return (-1);
287 		}
288 		kp->ki_sid = sess.s_sid;
289 		(void)memcpy(kp->ki_login, sess.s_login,
290 						sizeof(kp->ki_login));
291 		kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
292 		if (sess.s_leader == p)
293 			kp->ki_kiflag |= KI_SLEADER;
294 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
295 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
296 				_kvm_err(kd, kd->program,
297 					 "can't read tty at %p", sess.s_ttyp);
298 				return (-1);
299 			}
300 			if (tty.t_dev != NULL) {
301 				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
302 					_kvm_err(kd, kd->program,
303 						 "can't read cdev at %p",
304 						tty.t_dev);
305 					return (-1);
306 				}
307 #if 0
308 				kp->ki_tdev = t_cdev.si_udev;
309 #else
310 				kp->ki_tdev = NODEV;
311 #endif
312 			}
313 			if (tty.t_pgrp != NULL) {
314 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
315 					_kvm_err(kd, kd->program,
316 						 "can't read tpgrp at %p",
317 						tty.t_pgrp);
318 					return (-1);
319 				}
320 				kp->ki_tpgid = pgrp.pg_id;
321 			} else
322 				kp->ki_tpgid = -1;
323 			if (tty.t_session != NULL) {
324 				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
325 					_kvm_err(kd, kd->program,
326 					    "can't read session at %p",
327 					    tty.t_session);
328 					return (-1);
329 				}
330 				kp->ki_tsid = sess.s_sid;
331 			}
332 		} else {
333 nopgrp:
334 			kp->ki_tdev = NODEV;
335 		}
336 		if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
337 			(void)kvm_read(kd, (u_long)mtd.td_wmesg,
338 			    kp->ki_wmesg, WMESGLEN);
339 
340 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
341 		    (char *)&vmspace, sizeof(vmspace));
342 		kp->ki_size = vmspace.vm_map.size;
343 		/*
344 		 * Approximate the kernel's method of calculating
345 		 * this field.
346 		 */
347 #define		pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
348 		kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap);
349 		kp->ki_swrss = vmspace.vm_swrss;
350 		kp->ki_tsize = vmspace.vm_tsize;
351 		kp->ki_dsize = vmspace.vm_dsize;
352 		kp->ki_ssize = vmspace.vm_ssize;
353 
354 		switch (what & ~KERN_PROC_INC_THREAD) {
355 
356 		case KERN_PROC_PGRP:
357 			if (kp->ki_pgid != (pid_t)arg)
358 				continue;
359 			break;
360 
361 		case KERN_PROC_SESSION:
362 			if (kp->ki_sid != (pid_t)arg)
363 				continue;
364 			break;
365 
366 		case KERN_PROC_TTY:
367 			if ((proc.p_flag & P_CONTROLT) == 0 ||
368 			     kp->ki_tdev != (dev_t)arg)
369 				continue;
370 			break;
371 		}
372 		if (proc.p_comm[0] != 0)
373 			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
374 		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
375 		    sizeof(sysent));
376 		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
377 		    sizeof(svname));
378 		if (svname[0] != 0)
379 			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
380 		if ((proc.p_state != PRS_ZOMBIE) &&
381 		    (mtd.td_blocked != 0)) {
382 			kp->ki_kiflag |= KI_LOCKBLOCK;
383 			if (mtd.td_lockname)
384 				(void)kvm_read(kd,
385 				    (u_long)mtd.td_lockname,
386 				    kp->ki_lockname, LOCKNAMELEN);
387 			kp->ki_lockname[LOCKNAMELEN] = 0;
388 		}
389 		kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
390 		kp->ki_pid = proc.p_pid;
391 		kp->ki_siglist = proc.p_siglist;
392 		SIGSETOR(kp->ki_siglist, mtd.td_siglist);
393 		kp->ki_sigmask = mtd.td_sigmask;
394 		kp->ki_xstat = KW_EXITCODE(proc.p_xexit, proc.p_xsig);
395 		kp->ki_acflag = proc.p_acflag;
396 		kp->ki_lock = proc.p_lock;
397 		if (proc.p_state != PRS_ZOMBIE) {
398 			kp->ki_swtime = (ticks - proc.p_swtick) / hz;
399 			kp->ki_flag = proc.p_flag;
400 			kp->ki_sflag = 0;
401 			kp->ki_nice = proc.p_nice;
402 			kp->ki_traceflag = proc.p_traceflag;
403 			if (proc.p_state == PRS_NORMAL) {
404 				if (TD_ON_RUNQ(&mtd) ||
405 				    TD_CAN_RUN(&mtd) ||
406 				    TD_IS_RUNNING(&mtd)) {
407 					kp->ki_stat = SRUN;
408 				} else if (mtd.td_state ==
409 				    TDS_INHIBITED) {
410 					if (P_SHOULDSTOP(&proc)) {
411 						kp->ki_stat = SSTOP;
412 					} else if (
413 					    TD_IS_SLEEPING(&mtd)) {
414 						kp->ki_stat = SSLEEP;
415 					} else if (TD_ON_LOCK(&mtd)) {
416 						kp->ki_stat = SLOCK;
417 					} else {
418 						kp->ki_stat = SWAIT;
419 					}
420 				}
421 			} else {
422 				kp->ki_stat = SIDL;
423 			}
424 			/* Stuff from the thread */
425 			kp->ki_pri.pri_level = mtd.td_priority;
426 			kp->ki_pri.pri_native = mtd.td_base_pri;
427 			kp->ki_lastcpu = mtd.td_lastcpu;
428 			kp->ki_wchan = mtd.td_wchan;
429 			if (mtd.td_name[0] != 0)
430 				strlcpy(kp->ki_tdname, mtd.td_name, MAXCOMLEN);
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 		bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
458 		++bp;
459 		++cnt;
460 	}
461 	return (cnt);
462 }
463 
464 /*
465  * Build proc info array by reading in proc list from a crash dump.
466  * Return number of procs read.  maxcnt is the max we will read.
467  */
468 static int
469 kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
470     u_long a_zombproc, int maxcnt)
471 {
472 	struct kinfo_proc *bp = kd->procbase;
473 	int acnt, zcnt;
474 	struct proc *p;
475 
476 	if (KREAD(kd, a_allproc, &p)) {
477 		_kvm_err(kd, kd->program, "cannot read allproc");
478 		return (-1);
479 	}
480 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
481 	if (acnt < 0)
482 		return (acnt);
483 
484 	if (KREAD(kd, a_zombproc, &p)) {
485 		_kvm_err(kd, kd->program, "cannot read zombproc");
486 		return (-1);
487 	}
488 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
489 	if (zcnt < 0)
490 		zcnt = 0;
491 
492 	return (acnt + zcnt);
493 }
494 
495 struct kinfo_proc *
496 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
497 {
498 	int mib[4], st, nprocs;
499 	size_t size, osize;
500 	int temp_op;
501 
502 	if (kd->procbase != 0) {
503 		free((void *)kd->procbase);
504 		/*
505 		 * Clear this pointer in case this call fails.  Otherwise,
506 		 * kvm_close() will free it again.
507 		 */
508 		kd->procbase = 0;
509 	}
510 	if (ISALIVE(kd)) {
511 		size = 0;
512 		mib[0] = CTL_KERN;
513 		mib[1] = KERN_PROC;
514 		mib[2] = op;
515 		mib[3] = arg;
516 		temp_op = op & ~KERN_PROC_INC_THREAD;
517 		st = sysctl(mib,
518 		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
519 		    3 : 4, NULL, &size, NULL, 0);
520 		if (st == -1) {
521 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
522 			return (0);
523 		}
524 		/*
525 		 * We can't continue with a size of 0 because we pass
526 		 * it to realloc() (via _kvm_realloc()), and passing 0
527 		 * to realloc() results in undefined behavior.
528 		 */
529 		if (size == 0) {
530 			/*
531 			 * XXX: We should probably return an invalid,
532 			 * but non-NULL, pointer here so any client
533 			 * program trying to dereference it will
534 			 * crash.  However, _kvm_freeprocs() calls
535 			 * free() on kd->procbase if it isn't NULL,
536 			 * and free()'ing a junk pointer isn't good.
537 			 * Then again, _kvm_freeprocs() isn't used
538 			 * anywhere . . .
539 			 */
540 			kd->procbase = _kvm_malloc(kd, 1);
541 			goto liveout;
542 		}
543 		do {
544 			size += size / 10;
545 			kd->procbase = (struct kinfo_proc *)
546 			    _kvm_realloc(kd, kd->procbase, size);
547 			if (kd->procbase == 0)
548 				return (0);
549 			osize = size;
550 			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
551 			    temp_op == KERN_PROC_PROC ? 3 : 4,
552 			    kd->procbase, &size, NULL, 0);
553 		} while (st == -1 && errno == ENOMEM && size == osize);
554 		if (st == -1) {
555 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
556 			return (0);
557 		}
558 		/*
559 		 * We have to check the size again because sysctl()
560 		 * may "round up" oldlenp if oldp is NULL; hence it
561 		 * might've told us that there was data to get when
562 		 * there really isn't any.
563 		 */
564 		if (size > 0 &&
565 		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
566 			_kvm_err(kd, kd->program,
567 			    "kinfo_proc size mismatch (expected %zu, got %d)",
568 			    sizeof(struct kinfo_proc),
569 			    kd->procbase->ki_structsize);
570 			return (0);
571 		}
572 liveout:
573 		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
574 	} else {
575 		struct nlist nl[7], *p;
576 
577 		nl[0].n_name = "_nprocs";
578 		nl[1].n_name = "_allproc";
579 		nl[2].n_name = "_zombproc";
580 		nl[3].n_name = "_ticks";
581 		nl[4].n_name = "_hz";
582 		nl[5].n_name = "_cpu_tick_frequency";
583 		nl[6].n_name = 0;
584 
585 		if (kvm_nlist(kd, nl) != 0) {
586 			for (p = nl; p->n_type != 0; ++p)
587 				;
588 			_kvm_err(kd, kd->program,
589 				 "%s: no such symbol", p->n_name);
590 			return (0);
591 		}
592 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
593 			_kvm_err(kd, kd->program, "can't read nprocs");
594 			return (0);
595 		}
596 		if (KREAD(kd, nl[3].n_value, &ticks)) {
597 			_kvm_err(kd, kd->program, "can't read ticks");
598 			return (0);
599 		}
600 		if (KREAD(kd, nl[4].n_value, &hz)) {
601 			_kvm_err(kd, kd->program, "can't read hz");
602 			return (0);
603 		}
604 		if (KREAD(kd, nl[5].n_value, &cpu_tick_frequency)) {
605 			_kvm_err(kd, kd->program,
606 			    "can't read cpu_tick_frequency");
607 			return (0);
608 		}
609 		size = nprocs * sizeof(struct kinfo_proc);
610 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
611 		if (kd->procbase == 0)
612 			return (0);
613 
614 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
615 				      nl[2].n_value, nprocs);
616 		if (nprocs <= 0) {
617 			_kvm_freeprocs(kd);
618 			nprocs = 0;
619 		}
620 #ifdef notdef
621 		else {
622 			size = nprocs * sizeof(struct kinfo_proc);
623 			kd->procbase = realloc(kd->procbase, size);
624 		}
625 #endif
626 	}
627 	*cnt = nprocs;
628 	return (kd->procbase);
629 }
630 
631 void
632 _kvm_freeprocs(kvm_t *kd)
633 {
634 	if (kd->procbase) {
635 		free(kd->procbase);
636 		kd->procbase = 0;
637 	}
638 }
639 
640 void *
641 _kvm_realloc(kvm_t *kd, void *p, size_t n)
642 {
643 	void *np = (void *)realloc(p, n);
644 
645 	if (np == 0) {
646 		free(p);
647 		_kvm_err(kd, kd->program, "out of memory");
648 	}
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 
666 	if (!ISALIVE(kd)) {
667 		_kvm_err(kd, kd->program,
668 		    "cannot read user space from dead kernel");
669 		return (0);
670 	}
671 
672 	if (nchr == 0 || nchr > ARG_MAX)
673 		nchr = ARG_MAX;
674 	if (buflen == 0) {
675 		buf = malloc(nchr);
676 		if (buf == NULL) {
677 			_kvm_err(kd, kd->program, "cannot allocate memory");
678 			return (0);
679 		}
680 		buflen = nchr;
681 		argc = 32;
682 		bufp = malloc(sizeof(char *) * argc);
683 	} else if (nchr > buflen) {
684 		p = realloc(buf, nchr);
685 		if (p != NULL) {
686 			buf = p;
687 			buflen = nchr;
688 		}
689 	}
690 	oid[0] = CTL_KERN;
691 	oid[1] = KERN_PROC;
692 	oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
693 	oid[3] = kp->ki_pid;
694 	bufsz = buflen;
695 	if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
696 		/*
697 		 * If the supplied buf is too short to hold the requested
698 		 * value the sysctl returns with ENOMEM. The buf is filled
699 		 * with the truncated value and the returned bufsz is equal
700 		 * to the requested len.
701 		 */
702 		if (errno != ENOMEM || bufsz != (size_t)buflen)
703 			return (0);
704 		buf[bufsz - 1] = '\0';
705 		errno = 0;
706 	} else if (bufsz == 0) {
707 		return (0);
708 	}
709 	i = 0;
710 	p = buf;
711 	do {
712 		bufp[i++] = p;
713 		p += strlen(p) + 1;
714 		if (i >= argc) {
715 			argc += argc;
716 			bufp = realloc(bufp,
717 			    sizeof(char *) * argc);
718 		}
719 	} while (p < buf + bufsz);
720 	bufp[i++] = 0;
721 	return (bufp);
722 }
723 
724 char **
725 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
726 {
727 	return (kvm_argv(kd, kp, 0, nchr));
728 }
729 
730 char **
731 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
732 {
733 	return (kvm_argv(kd, kp, 1, nchr));
734 }
735