xref: /netbsd-src/lib/libkvm/kvm_proc.c (revision bada23909e740596d0a3785a73bd3583a9807fb8)
1 /*	$NetBSD: kvm_proc.c,v 1.29 1999/01/25 03:38:57 mrg Exp $	*/
2 
3 /*-
4  * Copyright (c) 1998 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Charles M. Hannum.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*-
40  * Copyright (c) 1989, 1992, 1993
41  *	The Regents of the University of California.  All rights reserved.
42  *
43  * This code is derived from software developed by the Computer Systems
44  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
45  * BG 91-66 and contributed to Berkeley.
46  *
47  * Redistribution and use in source and binary forms, with or without
48  * modification, are permitted provided that the following conditions
49  * are met:
50  * 1. Redistributions of source code must retain the above copyright
51  *    notice, this list of conditions and the following disclaimer.
52  * 2. Redistributions in binary form must reproduce the above copyright
53  *    notice, this list of conditions and the following disclaimer in the
54  *    documentation and/or other materials provided with the distribution.
55  * 3. All advertising materials mentioning features or use of this software
56  *    must display the following acknowledgement:
57  *	This product includes software developed by the University of
58  *	California, Berkeley and its contributors.
59  * 4. Neither the name of the University nor the names of its contributors
60  *    may be used to endorse or promote products derived from this software
61  *    without specific prior written permission.
62  *
63  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
64  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
65  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
66  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
67  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
68  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
69  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
70  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
71  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
72  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
73  * SUCH DAMAGE.
74  */
75 
76 #include <sys/cdefs.h>
77 #if defined(LIBC_SCCS) && !defined(lint)
78 #if 0
79 static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
80 #else
81 __RCSID("$NetBSD: kvm_proc.c,v 1.29 1999/01/25 03:38:57 mrg Exp $");
82 #endif
83 #endif /* LIBC_SCCS and not lint */
84 
85 /*
86  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
87  * users of this code, so we've factored it out into a separate module.
88  * Thus, we keep this grunge out of the other kvm applications (i.e.,
89  * most other applications are interested only in open/close/read/nlist).
90  */
91 
92 #include <sys/param.h>
93 #include <sys/user.h>
94 #include <sys/proc.h>
95 #include <sys/exec.h>
96 #include <sys/stat.h>
97 #include <sys/ioctl.h>
98 #include <sys/tty.h>
99 #include <stdlib.h>
100 #include <string.h>
101 #include <unistd.h>
102 #include <nlist.h>
103 #include <kvm.h>
104 
105 #include <vm/vm.h>
106 #include <vm/vm_param.h>
107 #include <vm/swap_pager.h>
108 
109 #if defined(UVM)
110 #include <uvm/uvm_extern.h>
111 #include <uvm/uvm_amap.h>
112 #endif
113 
114 #include <sys/sysctl.h>
115 
116 #include <limits.h>
117 #include <db.h>
118 #include <paths.h>
119 
120 #include "kvm_private.h"
121 
122 #define KREAD(kd, addr, obj) \
123 	(kvm_read(kd, addr, (void *)(obj), sizeof(*obj)) != sizeof(*obj))
124 
125 char		*_kvm_uread __P((kvm_t *, const struct proc *, u_long, u_long *));
126 #if !defined(UVM)
127 int		_kvm_coreinit __P((kvm_t *));
128 int		_kvm_readfromcore __P((kvm_t *, u_long, u_long));
129 int		_kvm_readfrompager __P((kvm_t *, struct vm_object *, u_long));
130 #endif
131 ssize_t		kvm_uread __P((kvm_t *, const struct proc *, u_long, char *,
132 		    size_t));
133 
134 static char	**kvm_argv __P((kvm_t *, const struct proc *, u_long, int,
135 		    int));
136 static int	kvm_deadprocs __P((kvm_t *, int, int, u_long, u_long, u_long,
137 		    int));
138 static char	**kvm_doargv __P((kvm_t *, const struct kinfo_proc *, int,
139 		    void (*)(struct ps_strings *, u_long *, int *)));
140 static int	kvm_proclist __P((kvm_t *, int, int, struct proc *,
141 		    struct kinfo_proc *, int));
142 static int	proc_verify __P((kvm_t *, u_long, const struct proc *));
143 static void	ps_str_a __P((struct ps_strings *, u_long *, int *));
144 static void	ps_str_e __P((struct ps_strings *, u_long *, int *));
145 
146 char *
147 _kvm_uread(kd, p, va, cnt)
148 	kvm_t *kd;
149 	const struct proc *p;
150 	u_long va;
151 	u_long *cnt;
152 {
153 	int true = 1;
154 	u_long addr, head;
155 	u_long offset;
156 	struct vm_map_entry vme;
157 #if defined(UVM)
158 	struct vm_amap amap;
159 	struct vm_anon *anonp, anon;
160 	struct vm_page pg;
161 	u_long slot;
162 #else
163 	struct vm_object vmo;
164 	int rv;
165 #endif
166 
167 	if (kd->swapspc == 0) {
168 		kd->swapspc = (char *)_kvm_malloc(kd, (size_t)kd->nbpg);
169 		if (kd->swapspc == 0)
170 			return (0);
171 	}
172 
173 	/*
174 	 * Look through the address map for the memory object
175 	 * that corresponds to the given virtual address.
176 	 * The header just has the entire valid range.
177 	 */
178 	head = (u_long)&p->p_vmspace->vm_map.header;
179 	addr = head;
180 	while (true) {
181 		if (KREAD(kd, addr, &vme))
182 			return (0);
183 
184 #if defined(UVM)
185 		if (va >= vme.start && va < vme.end &&
186 		    vme.aref.ar_amap != NULL)
187 			break;
188 
189 #else
190 		if (va >= vme.start && va < vme.end &&
191 		    vme.object.vm_object != 0)
192 			break;
193 #endif
194 
195 		addr = (u_long)vme.next;
196 		if (addr == head)
197 			return (0);
198 
199 	}
200 #if defined(UVM)
201 
202 	/*
203 	 * we found the map entry, now to find the object...
204 	 */
205 	if (vme.aref.ar_amap == NULL)
206 		return NULL;
207 
208 	addr = (u_long)vme.aref.ar_amap;
209 	if (KREAD(kd, addr, &amap))
210 		return NULL;
211 
212 	offset = va - vme.start;
213 	slot = offset / kd->nbpg + vme.aref.ar_pageoff;
214 	/* sanity-check slot number */
215 	if (slot  > amap.am_nslot)
216 		return NULL;
217 
218 	addr = (u_long)amap.am_anon + (offset / kd->nbpg) * sizeof(anonp);
219 	if (KREAD(kd, addr, &anonp))
220 		return NULL;
221 
222 	addr = (u_long)anonp;
223 	if (KREAD(kd, addr, &anon))
224 		return NULL;
225 
226 	addr = (u_long)anon.u.an_page;
227 	if (addr) {
228 		if (KREAD(kd, addr, &pg))
229 			return NULL;
230 
231 		if (pread(kd->pmfd, (void *)kd->swapspc, (size_t)kd->nbpg,
232 		    (off_t)pg.phys_addr) != kd->nbpg)
233 			return NULL;
234 	}
235 	else {
236 		if (pread(kd->swfd, (void *)kd->swapspc, (size_t)kd->nbpg,
237 		    (off_t)(anon.an_swslot * kd->nbpg)) != kd->nbpg)
238 			return NULL;
239 	}
240 #else
241 	/*
242 	 * We found the right object -- follow shadow links.
243 	 */
244 	offset = va - vme.start + vme.offset;
245 	addr = (u_long)vme.object.vm_object;
246 
247 	while (1) {
248 		/* Try reading the page from core first. */
249 		if ((rv = _kvm_readfromcore(kd, addr, offset)))
250 			break;
251 
252 		if (KREAD(kd, addr, &vmo))
253 			return (0);
254 
255 		/* If there is a pager here, see if it has the page. */
256 		if (vmo.pager != 0 &&
257 		    (rv = _kvm_readfrompager(kd, &vmo, offset)))
258 			break;
259 
260 		/* Move down the shadow chain. */
261 		addr = (u_long)vmo.shadow;
262 		if (addr == 0)
263 			return (0);
264 		offset += vmo.shadow_offset;
265 	}
266 
267 	if (rv == -1)
268 		return (0);
269 #endif
270 
271 	/* Found the page. */
272 	offset %= kd->nbpg;
273 	*cnt = kd->nbpg - offset;
274 	return (&kd->swapspc[(size_t)offset]);
275 }
276 
277 #if !defined(UVM)
278 
279 #define	vm_page_hash(kd, object, offset) \
280 	(((u_long)object + (u_long)(offset / kd->nbpg)) & kd->vm_page_hash_mask)
281 
282 int
283 _kvm_coreinit(kd)
284 	kvm_t *kd;
285 {
286 	struct nlist nlist[3];
287 
288 	nlist[0].n_name = "_vm_page_buckets";
289 	nlist[1].n_name = "_vm_page_hash_mask";
290 	nlist[2].n_name = 0;
291 	if (kvm_nlist(kd, nlist) != 0)
292 		return (-1);
293 
294 	if (KREAD(kd, nlist[0].n_value, &kd->vm_page_buckets) ||
295 	    KREAD(kd, nlist[1].n_value, &kd->vm_page_hash_mask))
296 		return (-1);
297 
298 	return (0);
299 }
300 
301 int
302 _kvm_readfromcore(kd, object, offset)
303 	kvm_t *kd;
304 	u_long object, offset;
305 {
306 	u_long addr;
307 	struct pglist bucket;
308 	struct vm_page mem;
309 	off_t seekpoint;
310 
311 	if (kd->vm_page_buckets == 0 &&
312 	    _kvm_coreinit(kd))
313 		return (-1);
314 
315 	addr = (u_long)&kd->vm_page_buckets[vm_page_hash(kd, object, offset)];
316 	if (KREAD(kd, addr, &bucket))
317 		return (-1);
318 
319 	addr = (u_long)bucket.tqh_first;
320 	offset &= ~(kd->nbpg -1);
321 	while (1) {
322 		if (addr == 0)
323 			return (0);
324 
325 		if (KREAD(kd, addr, &mem))
326 			return (-1);
327 
328 		if ((u_long)mem.object == object &&
329 		    (u_long)mem.offset == offset)
330 			break;
331 
332 		addr = (u_long)mem.hashq.tqe_next;
333 	}
334 
335 	seekpoint = mem.phys_addr;
336 
337 	if (pread(kd->pmfd, kd->swapspc, kd->nbpg, seekpoint) != kd->nbpg)
338 		return (-1);
339 
340 	return (1);
341 }
342 
343 int
344 _kvm_readfrompager(kd, vmop, offset)
345 	kvm_t *kd;
346 	struct vm_object *vmop;
347 	u_long offset;
348 {
349 	u_long addr;
350 	struct pager_struct pager;
351 	struct swpager swap;
352 	int ix;
353 	struct swblock swb;
354 	off_t seekpoint;
355 
356 	/* Read in the pager info and make sure it's a swap device. */
357 	addr = (u_long)vmop->pager;
358 	if (KREAD(kd, addr, &pager) || pager.pg_type != PG_SWAP)
359 		return (-1);
360 
361 	/* Read in the swap_pager private data. */
362 	addr = (u_long)pager.pg_data;
363 	if (KREAD(kd, addr, &swap))
364 		return (-1);
365 
366 	/*
367 	 * Calculate the paging offset, and make sure it's within the
368 	 * bounds of the pager.
369 	 */
370 	offset += vmop->paging_offset;
371 	ix = offset / dbtob(swap.sw_bsize);
372 #if 0
373 	if (swap.sw_blocks == 0 || ix >= swap.sw_nblocks)
374 		return (-1);
375 #else
376 	if (swap.sw_blocks == 0 || ix >= swap.sw_nblocks) {
377 		int i;
378 		printf("BUG BUG BUG BUG:\n");
379 		printf("object %p offset %lx pgoffset %lx ",
380 		    vmop, offset - vmop->paging_offset,
381 		    (u_long)vmop->paging_offset);
382 		printf("pager %p swpager %p\n",
383 		    vmop->pager, pager.pg_data);
384 		printf("osize %lx bsize %x blocks %p nblocks %x\n",
385 		    (u_long)swap.sw_osize, swap.sw_bsize, swap.sw_blocks,
386 		    swap.sw_nblocks);
387 		for (i = 0; i < swap.sw_nblocks; i++) {
388 			addr = (u_long)&swap.sw_blocks[i];
389 			if (KREAD(kd, addr, &swb))
390 				return (0);
391 			printf("sw_blocks[%d]: block %x mask %x\n", i,
392 			    swb.swb_block, swb.swb_mask);
393 		}
394 		return (-1);
395 	}
396 #endif
397 
398 	/* Read in the swap records. */
399 	addr = (u_long)&swap.sw_blocks[ix];
400 	if (KREAD(kd, addr, &swb))
401 		return (-1);
402 
403 	/* Calculate offset within pager. */
404 	offset %= dbtob(swap.sw_bsize);
405 
406 	/* Check that the page is actually present. */
407 	if ((swb.swb_mask & (1 << (offset / kd->nbpg))) == 0)
408 		return (0);
409 
410 	if (!ISALIVE(kd))
411 		return (-1);
412 
413 	/* Calculate the physical address and read the page. */
414 	seekpoint = dbtob(swb.swb_block) + (offset & ~(kd->nbpg -1));
415 
416 	if (pread(kd->swfd, kd->swapspc, kd->nbpg, seekpoint) != kd->nbpg)
417 		return (-1);
418 
419 	return (1);
420 }
421 #endif /* !defined(UVM) */
422 
423 /*
424  * Read proc's from memory file into buffer bp, which has space to hold
425  * at most maxcnt procs.
426  */
427 static int
428 kvm_proclist(kd, what, arg, p, bp, maxcnt)
429 	kvm_t *kd;
430 	int what, arg;
431 	struct proc *p;
432 	struct kinfo_proc *bp;
433 	int maxcnt;
434 {
435 	int cnt = 0;
436 	struct eproc eproc;
437 	struct pgrp pgrp;
438 	struct session sess;
439 	struct tty tty;
440 	struct proc proc;
441 
442 	for (; cnt < maxcnt && p != NULL; p = proc.p_list.le_next) {
443 		if (KREAD(kd, (u_long)p, &proc)) {
444 			_kvm_err(kd, kd->program, "can't read proc at %x", p);
445 			return (-1);
446 		}
447 		if (KREAD(kd, (u_long)proc.p_cred, &eproc.e_pcred) == 0)
448 			if (KREAD(kd, (u_long)eproc.e_pcred.pc_ucred,
449 			    &eproc.e_ucred)) {
450 				_kvm_err(kd, kd->program,
451 				    "can't read proc credentials at %x", p);
452 				return -1;
453 			}
454 
455 		switch(what) {
456 
457 		case KERN_PROC_PID:
458 			if (proc.p_pid != (pid_t)arg)
459 				continue;
460 			break;
461 
462 		case KERN_PROC_UID:
463 			if (eproc.e_ucred.cr_uid != (uid_t)arg)
464 				continue;
465 			break;
466 
467 		case KERN_PROC_RUID:
468 			if (eproc.e_pcred.p_ruid != (uid_t)arg)
469 				continue;
470 			break;
471 		}
472 		/*
473 		 * We're going to add another proc to the set.  If this
474 		 * will overflow the buffer, assume the reason is because
475 		 * nprocs (or the proc list) is corrupt and declare an error.
476 		 */
477 		if (cnt >= maxcnt) {
478 			_kvm_err(kd, kd->program, "nprocs corrupt");
479 			return (-1);
480 		}
481 		/*
482 		 * gather eproc
483 		 */
484 		eproc.e_paddr = p;
485 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
486 			_kvm_err(kd, kd->program, "can't read pgrp at %x",
487 				 proc.p_pgrp);
488 			return (-1);
489 		}
490 		eproc.e_sess = pgrp.pg_session;
491 		eproc.e_pgid = pgrp.pg_id;
492 		eproc.e_jobc = pgrp.pg_jobc;
493 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
494 			_kvm_err(kd, kd->program, "can't read session at %x",
495 				pgrp.pg_session);
496 			return (-1);
497 		}
498 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
499 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
500 				_kvm_err(kd, kd->program,
501 					 "can't read tty at %x", sess.s_ttyp);
502 				return (-1);
503 			}
504 			eproc.e_tdev = tty.t_dev;
505 			eproc.e_tsess = tty.t_session;
506 			if (tty.t_pgrp != NULL) {
507 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
508 					_kvm_err(kd, kd->program,
509 						 "can't read tpgrp at &x",
510 						tty.t_pgrp);
511 					return (-1);
512 				}
513 				eproc.e_tpgid = pgrp.pg_id;
514 			} else
515 				eproc.e_tpgid = -1;
516 		} else
517 			eproc.e_tdev = NODEV;
518 		eproc.e_flag = sess.s_ttyvp ? EPROC_CTTY : 0;
519 		if (sess.s_leader == p)
520 			eproc.e_flag |= EPROC_SLEADER;
521 		if (proc.p_wmesg)
522 			(void)kvm_read(kd, (u_long)proc.p_wmesg,
523 			    eproc.e_wmesg, WMESGLEN);
524 
525 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
526 		    (void *)&eproc.e_vm, sizeof(eproc.e_vm));
527 
528 		eproc.e_xsize = eproc.e_xrssize = 0;
529 		eproc.e_xccount = eproc.e_xswrss = 0;
530 
531 		switch (what) {
532 
533 		case KERN_PROC_PGRP:
534 			if (eproc.e_pgid != (pid_t)arg)
535 				continue;
536 			break;
537 
538 		case KERN_PROC_TTY:
539 			if ((proc.p_flag & P_CONTROLT) == 0 ||
540 			     eproc.e_tdev != (dev_t)arg)
541 				continue;
542 			break;
543 		}
544 		memcpy(&bp->kp_proc, &proc, sizeof(proc));
545 		memcpy(&bp->kp_eproc, &eproc, sizeof(eproc));
546 		++bp;
547 		++cnt;
548 	}
549 	return (cnt);
550 }
551 
552 /*
553  * Build proc info array by reading in proc list from a crash dump.
554  * Return number of procs read.  maxcnt is the max we will read.
555  */
556 static int
557 kvm_deadprocs(kd, what, arg, a_allproc, a_deadproc, a_zombproc, maxcnt)
558 	kvm_t *kd;
559 	int what, arg;
560 	u_long a_allproc;
561 	u_long a_deadproc;
562 	u_long a_zombproc;
563 	int maxcnt;
564 {
565 	struct kinfo_proc *bp = kd->procbase;
566 	int acnt, dcnt, zcnt;
567 	struct proc *p;
568 
569 	if (KREAD(kd, a_allproc, &p)) {
570 		_kvm_err(kd, kd->program, "cannot read allproc");
571 		return (-1);
572 	}
573 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
574 	if (acnt < 0)
575 		return (acnt);
576 
577 	if (KREAD(kd, a_deadproc, &p)) {
578 		_kvm_err(kd, kd->program, "cannot read deadproc");
579 		return (-1);
580 	}
581 
582 	dcnt = kvm_proclist(kd, what, arg, p, bp, maxcnt - acnt);
583 	if (dcnt < 0)
584 		dcnt = 0;
585 
586 	if (KREAD(kd, a_zombproc, &p)) {
587 		_kvm_err(kd, kd->program, "cannot read zombproc");
588 		return (-1);
589 	}
590 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt,
591 	    maxcnt - (acnt + dcnt));
592 	if (zcnt < 0)
593 		zcnt = 0;
594 
595 	return (acnt + zcnt);
596 }
597 
598 struct kinfo_proc *
599 kvm_getprocs(kd, op, arg, cnt)
600 	kvm_t *kd;
601 	int op, arg;
602 	int *cnt;
603 {
604 	size_t size;
605 	int mib[4], st, nprocs;
606 
607 	if (kd->procbase != 0) {
608 		free((void *)kd->procbase);
609 		/*
610 		 * Clear this pointer in case this call fails.  Otherwise,
611 		 * kvm_close() will free it again.
612 		 */
613 		kd->procbase = 0;
614 	}
615 	if (ISALIVE(kd)) {
616 		size = 0;
617 		mib[0] = CTL_KERN;
618 		mib[1] = KERN_PROC;
619 		mib[2] = op;
620 		mib[3] = arg;
621 		st = sysctl(mib, 4, NULL, &size, NULL, 0);
622 		if (st == -1) {
623 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
624 			return (0);
625 		}
626 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
627 		if (kd->procbase == 0)
628 			return (0);
629 		st = sysctl(mib, 4, kd->procbase, &size, NULL, 0);
630 		if (st == -1) {
631 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
632 			return (0);
633 		}
634 		if (size % sizeof(struct kinfo_proc) != 0) {
635 			_kvm_err(kd, kd->program,
636 				"proc size mismatch (%d total, %d chunks)",
637 				size, sizeof(struct kinfo_proc));
638 			return (0);
639 		}
640 		nprocs = size / sizeof(struct kinfo_proc);
641 	} else {
642 		struct nlist nl[5], *p;
643 
644 		nl[0].n_name = "_nprocs";
645 		nl[1].n_name = "_allproc";
646 		nl[2].n_name = "_deadproc";
647 		nl[3].n_name = "_zombproc";
648 		nl[4].n_name = 0;
649 
650 		if (kvm_nlist(kd, nl) != 0) {
651 			for (p = nl; p->n_type != 0; ++p)
652 				;
653 			_kvm_err(kd, kd->program,
654 				 "%s: no such symbol", p->n_name);
655 			return (0);
656 		}
657 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
658 			_kvm_err(kd, kd->program, "can't read nprocs");
659 			return (0);
660 		}
661 		size = nprocs * sizeof(struct kinfo_proc);
662 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
663 		if (kd->procbase == 0)
664 			return (0);
665 
666 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
667 		    nl[2].n_value, nl[3].n_value, nprocs);
668 #ifdef notdef
669 		size = nprocs * sizeof(struct kinfo_proc);
670 		(void)realloc(kd->procbase, size);
671 #endif
672 	}
673 	*cnt = nprocs;
674 	return (kd->procbase);
675 }
676 
677 void
678 _kvm_freeprocs(kd)
679 	kvm_t *kd;
680 {
681 	if (kd->procbase) {
682 		free(kd->procbase);
683 		kd->procbase = 0;
684 	}
685 }
686 
687 void *
688 _kvm_realloc(kd, p, n)
689 	kvm_t *kd;
690 	void *p;
691 	size_t n;
692 {
693 	void *np = (void *)realloc(p, n);
694 
695 	if (np == 0)
696 		_kvm_err(kd, kd->program, "out of memory");
697 	return (np);
698 }
699 
700 #ifndef MAX
701 #define MAX(a, b) ((a) > (b) ? (a) : (b))
702 #endif
703 
704 /*
705  * Read in an argument vector from the user address space of process p.
706  * addr if the user-space base address of narg null-terminated contiguous
707  * strings.  This is used to read in both the command arguments and
708  * environment strings.  Read at most maxcnt characters of strings.
709  */
710 static char **
711 kvm_argv(kd, p, addr, narg, maxcnt)
712 	kvm_t *kd;
713 	const struct proc *p;
714 	u_long addr;
715 	int narg;
716 	int maxcnt;
717 {
718 	char *np, *cp, *ep, *ap;
719 	u_long oaddr = (u_long)~0L;
720 	u_long len;
721 	size_t cc;
722 	char **argv;
723 
724 	/*
725 	 * Check that there aren't an unreasonable number of agruments,
726 	 * and that the address is in user space.
727 	 */
728 	if (narg > ARG_MAX || addr < kd->min_uva || addr >= kd->max_uva)
729 		return (0);
730 
731 	if (kd->argv == 0) {
732 		/*
733 		 * Try to avoid reallocs.
734 		 */
735 		kd->argc = MAX(narg + 1, 32);
736 		kd->argv = (char **)_kvm_malloc(kd, kd->argc *
737 						sizeof(*kd->argv));
738 		if (kd->argv == 0)
739 			return (0);
740 	} else if (narg + 1 > kd->argc) {
741 		kd->argc = MAX(2 * kd->argc, narg + 1);
742 		kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
743 						sizeof(*kd->argv));
744 		if (kd->argv == 0)
745 			return (0);
746 	}
747 	if (kd->argspc == 0) {
748 		kd->argspc = (char *)_kvm_malloc(kd, (size_t)kd->nbpg);
749 		if (kd->argspc == 0)
750 			return (0);
751 		kd->arglen = kd->nbpg;
752 	}
753 	if (kd->argbuf == 0) {
754 		kd->argbuf = (char *)_kvm_malloc(kd, (size_t)kd->nbpg);
755 		if (kd->argbuf == 0)
756 			return (0);
757 	}
758 	cc = sizeof(char *) * narg;
759 	if (kvm_uread(kd, p, addr, (void *)kd->argv, cc) != cc)
760 		return (0);
761 	ap = np = kd->argspc;
762 	argv = kd->argv;
763 	len = 0;
764 	/*
765 	 * Loop over pages, filling in the argument vector.
766 	 */
767 	while (argv < kd->argv + narg && *argv != 0) {
768 		addr = (u_long)*argv & ~(kd->nbpg - 1);
769 		if (addr != oaddr) {
770 			if (kvm_uread(kd, p, addr, kd->argbuf,
771 			    (size_t)kd->nbpg) != kd->nbpg)
772 				return (0);
773 			oaddr = addr;
774 		}
775 		addr = (u_long)*argv & (kd->nbpg - 1);
776 		cp = kd->argbuf + (size_t)addr;
777 		cc = kd->nbpg - (size_t)addr;
778 		if (maxcnt > 0 && cc > (size_t)(maxcnt - len))
779 			cc = (size_t)(maxcnt - len);
780 		ep = memchr(cp, '\0', cc);
781 		if (ep != 0)
782 			cc = ep - cp + 1;
783 		if (len + cc > kd->arglen) {
784 			int off;
785 			char **pp;
786 			char *op = kd->argspc;
787 
788 			kd->arglen *= 2;
789 			kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
790 			    (size_t)kd->arglen);
791 			if (kd->argspc == 0)
792 				return (0);
793 			/*
794 			 * Adjust argv pointers in case realloc moved
795 			 * the string space.
796 			 */
797 			off = kd->argspc - op;
798 			for (pp = kd->argv; pp < argv; pp++)
799 				*pp += off;
800 			ap += off;
801 			np += off;
802 		}
803 		memcpy(np, cp, cc);
804 		np += cc;
805 		len += cc;
806 		if (ep != 0) {
807 			*argv++ = ap;
808 			ap = np;
809 		} else
810 			*argv += cc;
811 		if (maxcnt > 0 && len >= maxcnt) {
812 			/*
813 			 * We're stopping prematurely.  Terminate the
814 			 * current string.
815 			 */
816 			if (ep == 0) {
817 				*np = '\0';
818 				*argv++ = ap;
819 			}
820 			break;
821 		}
822 	}
823 	/* Make sure argv is terminated. */
824 	*argv = 0;
825 	return (kd->argv);
826 }
827 
828 static void
829 ps_str_a(p, addr, n)
830 	struct ps_strings *p;
831 	u_long *addr;
832 	int *n;
833 {
834 	*addr = (u_long)p->ps_argvstr;
835 	*n = p->ps_nargvstr;
836 }
837 
838 static void
839 ps_str_e(p, addr, n)
840 	struct ps_strings *p;
841 	u_long *addr;
842 	int *n;
843 {
844 	*addr = (u_long)p->ps_envstr;
845 	*n = p->ps_nenvstr;
846 }
847 
848 /*
849  * Determine if the proc indicated by p is still active.
850  * This test is not 100% foolproof in theory, but chances of
851  * being wrong are very low.
852  */
853 static int
854 proc_verify(kd, kernp, p)
855 	kvm_t *kd;
856 	u_long kernp;
857 	const struct proc *p;
858 {
859 	struct proc kernproc;
860 
861 	/*
862 	 * Just read in the whole proc.  It's not that big relative
863 	 * to the cost of the read system call.
864 	 */
865 	if (kvm_read(kd, kernp, (void *)&kernproc, sizeof(kernproc)) !=
866 	    sizeof(kernproc))
867 		return (0);
868 	return (p->p_pid == kernproc.p_pid &&
869 		(kernproc.p_stat != SZOMB || p->p_stat == SZOMB));
870 }
871 
872 static char **
873 kvm_doargv(kd, kp, nchr, info)
874 	kvm_t *kd;
875 	const struct kinfo_proc *kp;
876 	int nchr;
877 	void (*info)(struct ps_strings *, u_long *, int *);
878 {
879 	const struct proc *p = &kp->kp_proc;
880 	char **ap;
881 	u_long addr;
882 	int cnt;
883 	struct ps_strings arginfo;
884 
885 	/*
886 	 * Pointers are stored at the top of the user stack.
887 	 */
888 	if (p->p_stat == SZOMB)
889 		return (0);
890 	cnt = kvm_uread(kd, p, kd->usrstack - sizeof(arginfo),
891 	    (void *)&arginfo, sizeof(arginfo));
892 	if (cnt != sizeof(arginfo))
893 		return (0);
894 
895 	(*info)(&arginfo, &addr, &cnt);
896 	if (cnt == 0)
897 		return (0);
898 	ap = kvm_argv(kd, p, addr, cnt, nchr);
899 	/*
900 	 * For live kernels, make sure this process didn't go away.
901 	 */
902 	if (ap != 0 && ISALIVE(kd) &&
903 	    !proc_verify(kd, (u_long)kp->kp_eproc.e_paddr, p))
904 		ap = 0;
905 	return (ap);
906 }
907 
908 /*
909  * Get the command args.  This code is now machine independent.
910  */
911 char **
912 kvm_getargv(kd, kp, nchr)
913 	kvm_t *kd;
914 	const struct kinfo_proc *kp;
915 	int nchr;
916 {
917 	return (kvm_doargv(kd, kp, nchr, ps_str_a));
918 }
919 
920 char **
921 kvm_getenvv(kd, kp, nchr)
922 	kvm_t *kd;
923 	const struct kinfo_proc *kp;
924 	int nchr;
925 {
926 	return (kvm_doargv(kd, kp, nchr, ps_str_e));
927 }
928 
929 /*
930  * Read from user space.  The user context is given by p.
931  */
932 ssize_t
933 kvm_uread(kd, p, uva, buf, len)
934 	kvm_t *kd;
935 	const struct proc *p;
936 	u_long uva;
937 	char *buf;
938 	size_t len;
939 {
940 	char *cp;
941 
942 	cp = buf;
943 	while (len > 0) {
944 		size_t cc;
945 		char *dp;
946 		u_long cnt;
947 
948 		dp = _kvm_uread(kd, p, uva, &cnt);
949 		if (dp == 0) {
950 			_kvm_err(kd, 0, "invalid address (%x)", uva);
951 			return (0);
952 		}
953 		cc = (size_t)MIN(cnt, len);
954 		memcpy(cp, dp, cc);
955 		cp += cc;
956 		uva += cc;
957 		len -= cc;
958 	}
959 	return (ssize_t)(cp - buf);
960 }
961