xref: /freebsd/lib/libkvm/kvm_proc.c (revision 02e9120893770924227138ba49df1edb3896112a)
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 sysentvec sysent;
125 	char svname[KI_EMULNAMELEN];
126 	struct thread *td = NULL;
127 	bool first_thread;
128 
129 	kp = &kinfo_proc;
130 	kp->ki_structsize = sizeof(kinfo_proc);
131 	/*
132 	 * Loop on the processes, then threads within the process if requested.
133 	 */
134 	if (what == KERN_PROC_ALL)
135 		what |= KERN_PROC_INC_THREAD;
136 	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
137 		memset(kp, 0, sizeof *kp);
138 		if (KREAD(kd, (u_long)p, &proc)) {
139 			_kvm_err(kd, kd->program, "can't read proc at %p", p);
140 			return (-1);
141 		}
142 		if (proc.p_state == PRS_NEW)
143 			continue;
144 		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
145 			kp->ki_ruid = ucred.cr_ruid;
146 			kp->ki_svuid = ucred.cr_svuid;
147 			kp->ki_rgid = ucred.cr_rgid;
148 			kp->ki_svgid = ucred.cr_svgid;
149 			kp->ki_cr_flags = ucred.cr_flags;
150 			if (ucred.cr_ngroups > KI_NGROUPS) {
151 				kp->ki_ngroups = KI_NGROUPS;
152 				kp->ki_cr_flags |= KI_CRF_GRP_OVERFLOW;
153 			} else
154 				kp->ki_ngroups = ucred.cr_ngroups;
155 			kvm_read(kd, (u_long)ucred.cr_groups, kp->ki_groups,
156 			    kp->ki_ngroups * sizeof(gid_t));
157 			kp->ki_uid = ucred.cr_uid;
158 			if (ucred.cr_prison != NULL) {
159 				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
160 					_kvm_err(kd, kd->program,
161 					    "can't read prison at %p",
162 					    ucred.cr_prison);
163 					return (-1);
164 				}
165 				kp->ki_jid = pr.pr_id;
166 			}
167 		}
168 
169 		switch(what & ~KERN_PROC_INC_THREAD) {
170 
171 		case KERN_PROC_GID:
172 			if (kp->ki_groups[0] != (gid_t)arg)
173 				continue;
174 			break;
175 
176 		case KERN_PROC_PID:
177 			if (proc.p_pid != (pid_t)arg)
178 				continue;
179 			break;
180 
181 		case KERN_PROC_RGID:
182 			if (kp->ki_rgid != (gid_t)arg)
183 				continue;
184 			break;
185 
186 		case KERN_PROC_UID:
187 			if (kp->ki_uid != (uid_t)arg)
188 				continue;
189 			break;
190 
191 		case KERN_PROC_RUID:
192 			if (kp->ki_ruid != (uid_t)arg)
193 				continue;
194 			break;
195 		}
196 		/*
197 		 * We're going to add another proc to the set.  If this
198 		 * will overflow the buffer, assume the reason is because
199 		 * nprocs (or the proc list) is corrupt and declare an error.
200 		 */
201 		if (cnt >= maxcnt) {
202 			_kvm_err(kd, kd->program, "nprocs corrupt");
203 			return (-1);
204 		}
205 		/*
206 		 * gather kinfo_proc
207 		 */
208 		kp->ki_paddr = p;
209 		kp->ki_addr = 0;	/* XXX uarea */
210 		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
211 		kp->ki_args = proc.p_args;
212 		kp->ki_numthreads = proc.p_numthreads;
213 		kp->ki_tracep = NULL;	/* XXXKIB do not expose ktr_io_params */
214 		kp->ki_textvp = proc.p_textvp;
215 		kp->ki_fd = proc.p_fd;
216 		kp->ki_pd = proc.p_pd;
217 		kp->ki_vmspace = proc.p_vmspace;
218 		if (proc.p_sigacts != NULL) {
219 			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
220 				_kvm_err(kd, kd->program,
221 				    "can't read sigacts at %p", proc.p_sigacts);
222 				return (-1);
223 			}
224 			kp->ki_sigignore = sigacts.ps_sigignore;
225 			kp->ki_sigcatch = sigacts.ps_sigcatch;
226 		}
227 #if 0
228 		if ((proc.p_flag & P_INMEM) && proc.p_stats != NULL) {
229 			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
230 				_kvm_err(kd, kd->program,
231 				    "can't read stats at %x", proc.p_stats);
232 				return (-1);
233 			}
234 			kp->ki_start = pstats.p_start;
235 
236 			/*
237 			 * XXX: The times here are probably zero and need
238 			 * to be calculated from the raw data in p_rux and
239 			 * p_crux.
240 			 */
241 			kp->ki_rusage = pstats.p_ru;
242 			kp->ki_childstime = pstats.p_cru.ru_stime;
243 			kp->ki_childutime = pstats.p_cru.ru_utime;
244 			/* Some callers want child-times in a single value */
245 			timeradd(&kp->ki_childstime, &kp->ki_childutime,
246 			    &kp->ki_childtime);
247 		}
248 #endif
249 		if (proc.p_oppid)
250 			kp->ki_ppid = proc.p_oppid;
251 		else if (proc.p_pptr) {
252 			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
253 				_kvm_err(kd, kd->program,
254 				    "can't read pproc at %p", proc.p_pptr);
255 				return (-1);
256 			}
257 			kp->ki_ppid = pproc.p_pid;
258 		} else
259 			kp->ki_ppid = 0;
260 		if (proc.p_pgrp == NULL)
261 			goto nopgrp;
262 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
263 			_kvm_err(kd, kd->program, "can't read pgrp at %p",
264 				 proc.p_pgrp);
265 			return (-1);
266 		}
267 		kp->ki_pgid = pgrp.pg_id;
268 		kp->ki_jobc = -1;	/* Or calculate?  Arguably not. */
269 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
270 			_kvm_err(kd, kd->program, "can't read session at %p",
271 				pgrp.pg_session);
272 			return (-1);
273 		}
274 		kp->ki_sid = sess.s_sid;
275 		(void)memcpy(kp->ki_login, sess.s_login,
276 						sizeof(kp->ki_login));
277 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
278 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
279 				_kvm_err(kd, kd->program,
280 					 "can't read tty at %p", sess.s_ttyp);
281 				return (-1);
282 			}
283 			if (tty.t_dev != NULL) {
284 				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
285 					_kvm_err(kd, kd->program,
286 						 "can't read cdev at %p",
287 						tty.t_dev);
288 					return (-1);
289 				}
290 #if 0
291 				kp->ki_tdev = t_cdev.si_udev;
292 #else
293 				kp->ki_tdev = NODEV;
294 #endif
295 			}
296 			if (tty.t_pgrp != NULL) {
297 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
298 					_kvm_err(kd, kd->program,
299 						 "can't read tpgrp at %p",
300 						tty.t_pgrp);
301 					return (-1);
302 				}
303 				kp->ki_tpgid = pgrp.pg_id;
304 			} else
305 				kp->ki_tpgid = -1;
306 			if (tty.t_session != NULL) {
307 				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
308 					_kvm_err(kd, kd->program,
309 					    "can't read session at %p",
310 					    tty.t_session);
311 					return (-1);
312 				}
313 				kp->ki_tsid = sess.s_sid;
314 			}
315 		} else {
316 nopgrp:
317 			kp->ki_tdev = NODEV;
318 		}
319 
320 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
321 		    (char *)&vmspace, sizeof(vmspace));
322 		kp->ki_size = vmspace.vm_map.size;
323 		/*
324 		 * Approximate the kernel's method of calculating
325 		 * this field.
326 		 */
327 #define		pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
328 		kp->ki_rssize = pmap_resident_count(&vmspace.vm_pmap);
329 		kp->ki_swrss = vmspace.vm_swrss;
330 		kp->ki_tsize = vmspace.vm_tsize;
331 		kp->ki_dsize = vmspace.vm_dsize;
332 		kp->ki_ssize = vmspace.vm_ssize;
333 
334 		switch (what & ~KERN_PROC_INC_THREAD) {
335 
336 		case KERN_PROC_PGRP:
337 			if (kp->ki_pgid != (pid_t)arg)
338 				continue;
339 			break;
340 
341 		case KERN_PROC_SESSION:
342 			if (kp->ki_sid != (pid_t)arg)
343 				continue;
344 			break;
345 
346 		case KERN_PROC_TTY:
347 			if ((proc.p_flag & P_CONTROLT) == 0 ||
348 			     kp->ki_tdev != (dev_t)arg)
349 				continue;
350 			break;
351 		}
352 		if (proc.p_comm[0] != 0)
353 			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
354 		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
355 		    sizeof(sysent));
356 		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
357 		    sizeof(svname));
358 		if (svname[0] != 0)
359 			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
360 		kp->ki_runtime = cputick2usec(proc.p_rux.rux_runtime);
361 		kp->ki_pid = proc.p_pid;
362 		kp->ki_xstat = KW_EXITCODE(proc.p_xexit, proc.p_xsig);
363 		kp->ki_acflag = proc.p_acflag;
364 		kp->ki_lock = proc.p_lock;
365 		kp->ki_tdev_freebsd11 = kp->ki_tdev; /* truncate */
366 
367 		/* Per-thread items; iterate as appropriate. */
368 		td = TAILQ_FIRST(&proc.p_threads);
369 		for (first_thread = true; cnt < maxcnt && td != NULL &&
370 		    (first_thread || (what & KERN_PROC_INC_THREAD));
371 		    first_thread = false) {
372 			if (proc.p_state != PRS_ZOMBIE) {
373 				if (KREAD(kd, (u_long)td, &mtd)) {
374 					_kvm_err(kd, kd->program,
375 					    "can't read thread at %p", td);
376 					return (-1);
377 				}
378 				if (what & KERN_PROC_INC_THREAD)
379 					td = TAILQ_NEXT(&mtd, td_plist);
380 			} else
381 				td = NULL;
382 			if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
383 				(void)kvm_read(kd, (u_long)mtd.td_wmesg,
384 				    kp->ki_wmesg, WMESGLEN);
385 			else
386 				memset(kp->ki_wmesg, 0, WMESGLEN);
387 			if (proc.p_pgrp == NULL) {
388 				kp->ki_kiflag = 0;
389 			} else {
390 				kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
391 				if (sess.s_leader == p)
392 					kp->ki_kiflag |= KI_SLEADER;
393 			}
394 			if ((proc.p_state != PRS_ZOMBIE) &&
395 			    (mtd.td_blocked != 0)) {
396 				kp->ki_kiflag |= KI_LOCKBLOCK;
397 				if (mtd.td_lockname)
398 					(void)kvm_read(kd,
399 					    (u_long)mtd.td_lockname,
400 					    kp->ki_lockname, LOCKNAMELEN);
401 				else
402 					memset(kp->ki_lockname, 0,
403 					    LOCKNAMELEN);
404 				kp->ki_lockname[LOCKNAMELEN] = 0;
405 			} else
406 				kp->ki_kiflag &= ~KI_LOCKBLOCK;
407 			kp->ki_siglist = proc.p_siglist;
408 			if (proc.p_state != PRS_ZOMBIE) {
409 				SIGSETOR(kp->ki_siglist, mtd.td_siglist);
410 				kp->ki_sigmask = mtd.td_sigmask;
411 				kp->ki_swtime = (ticks - proc.p_swtick) / hz;
412 				kp->ki_flag = proc.p_flag;
413 				kp->ki_sflag = 0;
414 				kp->ki_nice = proc.p_nice;
415 				kp->ki_traceflag = proc.p_traceflag;
416 				if (proc.p_state == PRS_NORMAL) {
417 					if (TD_ON_RUNQ(&mtd) ||
418 					    TD_CAN_RUN(&mtd) ||
419 					    TD_IS_RUNNING(&mtd)) {
420 						kp->ki_stat = SRUN;
421 					} else if (TD_GET_STATE(&mtd) ==
422 					    TDS_INHIBITED) {
423 						if (P_SHOULDSTOP(&proc)) {
424 							kp->ki_stat = SSTOP;
425 						} else if (
426 						    TD_IS_SLEEPING(&mtd)) {
427 							kp->ki_stat = SSLEEP;
428 						} else if (TD_ON_LOCK(&mtd)) {
429 							kp->ki_stat = SLOCK;
430 						} else {
431 							kp->ki_stat = SWAIT;
432 						}
433 					}
434 				} else {
435 					kp->ki_stat = SIDL;
436 				}
437 				/* Stuff from the thread */
438 				kp->ki_pri.pri_level = mtd.td_priority;
439 				kp->ki_pri.pri_native = mtd.td_base_pri;
440 				kp->ki_lastcpu = mtd.td_lastcpu;
441 				kp->ki_wchan = mtd.td_wchan;
442 				kp->ki_oncpu = mtd.td_oncpu;
443 				if (mtd.td_name[0] != '\0')
444 					strlcpy(kp->ki_tdname, mtd.td_name,
445 					    sizeof(kp->ki_tdname));
446 				else
447 					memset(kp->ki_tdname, 0,
448 					    sizeof(kp->ki_tdname));
449 				kp->ki_pctcpu = 0;
450 				kp->ki_rqindex = 0;
451 
452 				/*
453 				 * Note: legacy fields; wraps at NO_CPU_OLD
454 				 * or the old max CPU value as appropriate
455 				 */
456 				if (mtd.td_lastcpu == NOCPU)
457 					kp->ki_lastcpu_old = NOCPU_OLD;
458 				else if (mtd.td_lastcpu > MAXCPU_OLD)
459 					kp->ki_lastcpu_old = MAXCPU_OLD;
460 				else
461 					kp->ki_lastcpu_old = mtd.td_lastcpu;
462 
463 				if (mtd.td_oncpu == NOCPU)
464 					kp->ki_oncpu_old = NOCPU_OLD;
465 				else if (mtd.td_oncpu > MAXCPU_OLD)
466 					kp->ki_oncpu_old = MAXCPU_OLD;
467 				else
468 					kp->ki_oncpu_old = mtd.td_oncpu;
469 				kp->ki_tid = mtd.td_tid;
470 			} else {
471 				memset(&kp->ki_sigmask, 0,
472 				    sizeof(kp->ki_sigmask));
473 				kp->ki_stat = SZOMB;
474 				kp->ki_tid = 0;
475 			}
476 
477 			bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
478 			++bp;
479 			++cnt;
480 		}
481 	}
482 	return (cnt);
483 }
484 
485 /*
486  * Build proc info array by reading in proc list from a crash dump.
487  * Return number of procs read.  maxcnt is the max we will read.
488  */
489 static int
490 kvm_deadprocs(kvm_t *kd, int what, int arg, u_long a_allproc,
491     u_long a_zombproc, int maxcnt)
492 {
493 	struct kinfo_proc *bp = kd->procbase;
494 	int acnt, zcnt = 0;
495 	struct proc *p;
496 
497 	if (KREAD(kd, a_allproc, &p)) {
498 		_kvm_err(kd, kd->program, "cannot read allproc");
499 		return (-1);
500 	}
501 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
502 	if (acnt < 0)
503 		return (acnt);
504 
505 	if (a_zombproc != 0) {
506 		if (KREAD(kd, a_zombproc, &p)) {
507 			_kvm_err(kd, kd->program, "cannot read zombproc");
508 			return (-1);
509 		}
510 		zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
511 		if (zcnt < 0)
512 			zcnt = 0;
513 	}
514 
515 	return (acnt + zcnt);
516 }
517 
518 struct kinfo_proc *
519 kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt)
520 {
521 	int mib[4], st, nprocs;
522 	size_t size, osize;
523 	int temp_op;
524 
525 	if (kd->procbase != 0) {
526 		free((void *)kd->procbase);
527 		/*
528 		 * Clear this pointer in case this call fails.  Otherwise,
529 		 * kvm_close() will free it again.
530 		 */
531 		kd->procbase = 0;
532 	}
533 	if (ISALIVE(kd)) {
534 		size = 0;
535 		mib[0] = CTL_KERN;
536 		mib[1] = KERN_PROC;
537 		mib[2] = op;
538 		mib[3] = arg;
539 		temp_op = op & ~KERN_PROC_INC_THREAD;
540 		st = sysctl(mib,
541 		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
542 		    3 : 4, NULL, &size, NULL, 0);
543 		if (st == -1) {
544 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
545 			return (0);
546 		}
547 		/*
548 		 * We can't continue with a size of 0 because we pass
549 		 * it to realloc() (via _kvm_realloc()), and passing 0
550 		 * to realloc() results in undefined behavior.
551 		 */
552 		if (size == 0) {
553 			/*
554 			 * XXX: We should probably return an invalid,
555 			 * but non-NULL, pointer here so any client
556 			 * program trying to dereference it will
557 			 * crash.  However, _kvm_freeprocs() calls
558 			 * free() on kd->procbase if it isn't NULL,
559 			 * and free()'ing a junk pointer isn't good.
560 			 * Then again, _kvm_freeprocs() isn't used
561 			 * anywhere . . .
562 			 */
563 			kd->procbase = _kvm_malloc(kd, 1);
564 			goto liveout;
565 		}
566 		do {
567 			size += size / 10;
568 			kd->procbase = (struct kinfo_proc *)
569 			    _kvm_realloc(kd, kd->procbase, size);
570 			if (kd->procbase == NULL)
571 				return (0);
572 			osize = size;
573 			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
574 			    temp_op == KERN_PROC_PROC ? 3 : 4,
575 			    kd->procbase, &size, NULL, 0);
576 		} while (st == -1 && errno == ENOMEM && size == osize);
577 		if (st == -1) {
578 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
579 			return (0);
580 		}
581 		/*
582 		 * We have to check the size again because sysctl()
583 		 * may "round up" oldlenp if oldp is NULL; hence it
584 		 * might've told us that there was data to get when
585 		 * there really isn't any.
586 		 */
587 		if (size > 0 &&
588 		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
589 			_kvm_err(kd, kd->program,
590 			    "kinfo_proc size mismatch (expected %zu, got %d)",
591 			    sizeof(struct kinfo_proc),
592 			    kd->procbase->ki_structsize);
593 			return (0);
594 		}
595 liveout:
596 		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
597 	} else {
598 		struct nlist nl[6], *p;
599 		struct nlist nlz[2];
600 
601 		nl[0].n_name = "_nprocs";
602 		nl[1].n_name = "_allproc";
603 		nl[2].n_name = "_ticks";
604 		nl[3].n_name = "_hz";
605 		nl[4].n_name = "_cpu_tick_frequency";
606 		nl[5].n_name = 0;
607 
608 		nlz[0].n_name = "_zombproc";
609 		nlz[1].n_name = 0;
610 
611 		if (!kd->arch->ka_native(kd)) {
612 			_kvm_err(kd, kd->program,
613 			    "cannot read procs from non-native core");
614 			return (0);
615 		}
616 
617 		if (kvm_nlist(kd, nl) != 0) {
618 			for (p = nl; p->n_type != 0; ++p)
619 				;
620 			_kvm_err(kd, kd->program,
621 				 "%s: no such symbol", p->n_name);
622 			return (0);
623 		}
624 		(void) kvm_nlist(kd, nlz);	/* attempt to get zombproc */
625 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
626 			_kvm_err(kd, kd->program, "can't read nprocs");
627 			return (0);
628 		}
629 		/*
630 		 * If returning all threads, we don't know how many that
631 		 * might be.  Presume that there are, on average, no more
632 		 * than 10 threads per process.
633 		 */
634 		if (op == KERN_PROC_ALL || (op & KERN_PROC_INC_THREAD))
635 			nprocs *= 10;		/* XXX */
636 		if (KREAD(kd, nl[2].n_value, &ticks)) {
637 			_kvm_err(kd, kd->program, "can't read ticks");
638 			return (0);
639 		}
640 		if (KREAD(kd, nl[3].n_value, &hz)) {
641 			_kvm_err(kd, kd->program, "can't read hz");
642 			return (0);
643 		}
644 		if (KREAD(kd, nl[4].n_value, &cpu_tick_frequency)) {
645 			_kvm_err(kd, kd->program,
646 			    "can't read cpu_tick_frequency");
647 			return (0);
648 		}
649 		size = nprocs * sizeof(struct kinfo_proc);
650 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
651 		if (kd->procbase == NULL)
652 			return (0);
653 
654 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
655 				      nlz[0].n_value, nprocs);
656 		if (nprocs <= 0) {
657 			_kvm_freeprocs(kd);
658 			nprocs = 0;
659 		}
660 #ifdef notdef
661 		else {
662 			size = nprocs * sizeof(struct kinfo_proc);
663 			kd->procbase = realloc(kd->procbase, size);
664 		}
665 #endif
666 	}
667 	*cnt = nprocs;
668 	return (kd->procbase);
669 }
670 
671 void
672 _kvm_freeprocs(kvm_t *kd)
673 {
674 
675 	free(kd->procbase);
676 	kd->procbase = NULL;
677 }
678 
679 void *
680 _kvm_realloc(kvm_t *kd, void *p, size_t n)
681 {
682 	void *np;
683 
684 	np = reallocf(p, n);
685 	if (np == NULL)
686 		_kvm_err(kd, kd->program, "out of memory");
687 	return (np);
688 }
689 
690 /*
691  * Get the command args or environment.
692  */
693 static char **
694 kvm_argv(kvm_t *kd, const struct kinfo_proc *kp, int env, int nchr)
695 {
696 	int oid[4];
697 	int i;
698 	size_t bufsz;
699 	static int buflen;
700 	static char *buf, *p;
701 	static char **bufp;
702 	static int argc;
703 	char **nbufp;
704 
705 	if (!ISALIVE(kd)) {
706 		_kvm_err(kd, kd->program,
707 		    "cannot read user space from dead kernel");
708 		return (NULL);
709 	}
710 
711 	if (nchr == 0 || nchr > ARG_MAX)
712 		nchr = ARG_MAX;
713 	if (buflen == 0) {
714 		buf = malloc(nchr);
715 		if (buf == NULL) {
716 			_kvm_err(kd, kd->program, "cannot allocate memory");
717 			return (NULL);
718 		}
719 		argc = 32;
720 		bufp = malloc(sizeof(char *) * argc);
721 		if (bufp == NULL) {
722 			free(buf);
723 			buf = NULL;
724 			_kvm_err(kd, kd->program, "cannot allocate memory");
725 			return (NULL);
726 		}
727 		buflen = nchr;
728 	} else if (nchr > buflen) {
729 		p = realloc(buf, nchr);
730 		if (p != NULL) {
731 			buf = p;
732 			buflen = nchr;
733 		}
734 	}
735 	oid[0] = CTL_KERN;
736 	oid[1] = KERN_PROC;
737 	oid[2] = env ? KERN_PROC_ENV : KERN_PROC_ARGS;
738 	oid[3] = kp->ki_pid;
739 	bufsz = buflen;
740 	if (sysctl(oid, 4, buf, &bufsz, 0, 0) == -1) {
741 		/*
742 		 * If the supplied buf is too short to hold the requested
743 		 * value the sysctl returns with ENOMEM. The buf is filled
744 		 * with the truncated value and the returned bufsz is equal
745 		 * to the requested len.
746 		 */
747 		if (errno != ENOMEM || bufsz != (size_t)buflen)
748 			return (NULL);
749 		buf[bufsz - 1] = '\0';
750 		errno = 0;
751 	} else if (bufsz == 0)
752 		return (NULL);
753 	i = 0;
754 	p = buf;
755 	do {
756 		bufp[i++] = p;
757 		p += strlen(p) + 1;
758 		if (i >= argc) {
759 			argc += argc;
760 			nbufp = realloc(bufp, sizeof(char *) * argc);
761 			if (nbufp == NULL)
762 				return (NULL);
763 			bufp = nbufp;
764 		}
765 	} while (p < buf + bufsz);
766 	bufp[i++] = 0;
767 	return (bufp);
768 }
769 
770 char **
771 kvm_getargv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
772 {
773 	return (kvm_argv(kd, kp, 0, nchr));
774 }
775 
776 char **
777 kvm_getenvv(kvm_t *kd, const struct kinfo_proc *kp, int nchr)
778 {
779 	return (kvm_argv(kd, kp, 1, nchr));
780 }
781