xref: /netbsd-src/lib/libkvm/kvm_proc.c (revision 1f2744e6e4915c9da2a3f980279398c4cf7d5e6d)
1 /*-
2  * Copyright (c) 1994 Charles Hannum.
3  * Copyright (c) 1989, 1992, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software developed by the Computer Systems
7  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
8  * BG 91-66 and contributed to Berkeley.
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 University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #if defined(LIBC_SCCS) && !defined(lint)
40 static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
41 #endif /* LIBC_SCCS and not lint */
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 #include <sys/user.h>
52 #include <sys/proc.h>
53 #include <sys/exec.h>
54 #include <sys/stat.h>
55 #include <sys/ioctl.h>
56 #include <sys/tty.h>
57 #include <stdlib.h>
58 #include <unistd.h>
59 #include <nlist.h>
60 #include <kvm.h>
61 
62 #include <vm/vm.h>
63 #include <vm/vm_param.h>
64 #include <vm/swap_pager.h>
65 
66 #include <sys/sysctl.h>
67 
68 #include <limits.h>
69 #include <db.h>
70 #include <paths.h>
71 
72 #include "kvm_private.h"
73 
74 #define KREAD(kd, addr, obj) \
75 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
76 
77 int _kvm_readfromcore __P((kvm_t *, u_long, u_long));
78 int _kvm_readfrompager __P((kvm_t *, struct vm_object *, u_long));
79 ssize_t kvm_uread __P((kvm_t *, const struct proc *, u_long, char *, size_t));
80 
81 char *
82 _kvm_uread(kd, p, va, cnt)
83 	kvm_t *kd;
84 	const struct proc *p;
85 	u_long va;
86 	u_long *cnt;
87 {
88 	register u_long addr, head;
89 	register u_long offset;
90 	struct vm_map_entry vme;
91 	struct vm_object vmo;
92 	int rv;
93 
94 	if (kd->swapspc == 0) {
95 		kd->swapspc = (char *)_kvm_malloc(kd, kd->nbpg);
96 		if (kd->swapspc == 0)
97 			return (0);
98 	}
99 
100 	/*
101 	 * Look through the address map for the memory object
102 	 * that corresponds to the given virtual address.
103 	 * The header just has the entire valid range.
104 	 */
105 	head = (u_long)&p->p_vmspace->vm_map.header;
106 	addr = head;
107 	while (1) {
108 		if (KREAD(kd, addr, &vme))
109 			return (0);
110 
111 		if (va >= vme.start && va < vme.end &&
112 		    vme.object.vm_object != 0)
113 			break;
114 
115 		addr = (u_long)vme.next;
116 		if (addr == head)
117 			return (0);
118 	}
119 
120 	/*
121 	 * We found the right object -- follow shadow links.
122 	 */
123 	offset = va - vme.start + vme.offset;
124 	addr = (u_long)vme.object.vm_object;
125 
126 	while (1) {
127 		/* Try reading the page from core first. */
128 		if ((rv = _kvm_readfromcore(kd, addr, offset)))
129 			break;
130 
131 		if (KREAD(kd, addr, &vmo))
132 			return (0);
133 
134 		/* If there is a pager here, see if it has the page. */
135 		if (vmo.pager != 0 &&
136 		    (rv = _kvm_readfrompager(kd, &vmo, offset)))
137 			break;
138 
139 		/* Move down the shadow chain. */
140 		addr = (u_long)vmo.shadow;
141 		if (addr == 0)
142 			return (0);
143 		offset += vmo.shadow_offset;
144 	}
145 
146 	if (rv == -1)
147 		return (0);
148 
149 	/* Found the page. */
150 	offset %= kd->nbpg;
151 	*cnt = kd->nbpg - offset;
152 	return (&kd->swapspc[offset]);
153 }
154 
155 #define	vm_page_hash(kd, object, offset) \
156 	(((u_long)object + (u_long)(offset / kd->nbpg)) & kd->vm_page_hash_mask)
157 
158 int
159 _kvm_coreinit(kd)
160 	kvm_t *kd;
161 {
162 	struct nlist nlist[3];
163 
164 	nlist[0].n_name = "_vm_page_buckets";
165 	nlist[1].n_name = "_vm_page_hash_mask";
166 	nlist[2].n_name = 0;
167 	if (kvm_nlist(kd, nlist) != 0)
168 		return (-1);
169 
170 	if (KREAD(kd, nlist[0].n_value, &kd->vm_page_buckets) ||
171 	    KREAD(kd, nlist[1].n_value, &kd->vm_page_hash_mask))
172 		return (-1);
173 
174 	return (0);
175 }
176 
177 int
178 _kvm_readfromcore(kd, object, offset)
179 	kvm_t *kd;
180 	u_long object, offset;
181 {
182 	u_long addr;
183 	struct pglist bucket;
184 	struct vm_page mem;
185 	off_t seekpoint;
186 
187 	if (kd->vm_page_buckets == 0 &&
188 	    _kvm_coreinit(kd))
189 		return (-1);
190 
191 	addr = (u_long)&kd->vm_page_buckets[vm_page_hash(kd, object, offset)];
192 	if (KREAD(kd, addr, &bucket))
193 		return (-1);
194 
195 	addr = (u_long)bucket.tqh_first;
196 	offset &= ~(kd->nbpg -1);
197 	while (1) {
198 		if (addr == 0)
199 			return (0);
200 
201 		if (KREAD(kd, addr, &mem))
202 			return (-1);
203 
204 		if ((u_long)mem.object == object &&
205 		    (u_long)mem.offset == offset)
206 			break;
207 
208 		addr = (u_long)mem.hashq.tqe_next;
209 	}
210 
211 	seekpoint = mem.phys_addr;
212 
213 	if (lseek(kd->pmfd, seekpoint, 0) == -1)
214 		return (-1);
215 	if (read(kd->pmfd, kd->swapspc, kd->nbpg) != kd->nbpg)
216 		return (-1);
217 
218 	return (1);
219 }
220 
221 int
222 _kvm_readfrompager(kd, vmop, offset)
223 	kvm_t *kd;
224 	struct vm_object *vmop;
225 	u_long offset;
226 {
227 	u_long addr;
228 	struct pager_struct pager;
229 	struct swpager swap;
230 	int ix;
231 	struct swblock swb;
232 	off_t seekpoint;
233 
234 	/* Read in the pager info and make sure it's a swap device. */
235 	addr = (u_long)vmop->pager;
236 	if (KREAD(kd, addr, &pager) || pager.pg_type != PG_SWAP)
237 		return (-1);
238 
239 	/* Read in the swap_pager private data. */
240 	addr = (u_long)pager.pg_data;
241 	if (KREAD(kd, addr, &swap))
242 		return (-1);
243 
244 	/*
245 	 * Calculate the paging offset, and make sure it's within the
246 	 * bounds of the pager.
247 	 */
248 	offset += vmop->paging_offset;
249 	ix = offset / dbtob(swap.sw_bsize);
250 #if 0
251 	if (swap.sw_blocks == 0 || ix >= swap.sw_nblocks)
252 		return (-1);
253 #else
254 	if (swap.sw_blocks == 0 || ix >= swap.sw_nblocks) {
255 		int i;
256 		printf("BUG BUG BUG BUG:\n");
257 		printf("object %x offset %x pgoffset %x pager %x swpager %x\n",
258 		    vmop, offset - vmop->paging_offset, vmop->paging_offset,
259 		    vmop->pager, pager.pg_data);
260 		printf("osize %x bsize %x blocks %x nblocks %x\n",
261 		    swap.sw_osize, swap.sw_bsize, swap.sw_blocks,
262 		    swap.sw_nblocks);
263 		for (ix = 0; ix < swap.sw_nblocks; ix++) {
264 			addr = (u_long)&swap.sw_blocks[ix];
265 			if (KREAD(kd, addr, &swb))
266 				return (0);
267 			printf("sw_blocks[%d]: block %x mask %x\n", ix,
268 			    swb.swb_block, swb.swb_mask);
269 		}
270 		return (-1);
271 	}
272 #endif
273 
274 	/* Read in the swap records. */
275 	addr = (u_long)&swap.sw_blocks[ix];
276 	if (KREAD(kd, addr, &swb))
277 		return (-1);
278 
279 	/* Calculate offset within pager. */
280 	offset %= dbtob(swap.sw_bsize);
281 
282 	/* Check that the page is actually present. */
283 	if ((swb.swb_mask & (1 << (offset / kd->nbpg))) == 0)
284 		return (0);
285 
286 	if (!ISALIVE(kd))
287 		return (-1);
288 
289 	/* Calculate the physical address and read the page. */
290 	seekpoint = dbtob(swb.swb_block) + (offset & ~(kd->nbpg -1));
291 
292 	if (lseek(kd->swfd, seekpoint, 0) == -1)
293 		return (-1);
294 	if (read(kd->swfd, kd->swapspc, kd->nbpg) != kd->nbpg)
295 		return (-1);
296 
297 	return (1);
298 }
299 
300 /*
301  * Read proc's from memory file into buffer bp, which has space to hold
302  * at most maxcnt procs.
303  */
304 static int
305 kvm_proclist(kd, what, arg, p, bp, maxcnt)
306 	kvm_t *kd;
307 	int what, arg;
308 	struct proc *p;
309 	struct kinfo_proc *bp;
310 	int maxcnt;
311 {
312 	register int cnt = 0;
313 	struct eproc eproc;
314 	struct pgrp pgrp;
315 	struct session sess;
316 	struct tty tty;
317 	struct proc proc;
318 
319 	for (; cnt < maxcnt && p != NULL; p = proc.p_list.le_next) {
320 		if (KREAD(kd, (u_long)p, &proc)) {
321 			_kvm_err(kd, kd->program, "can't read proc at %x", p);
322 			return (-1);
323 		}
324 		if (KREAD(kd, (u_long)proc.p_cred, &eproc.e_pcred) == 0)
325 			KREAD(kd, (u_long)eproc.e_pcred.pc_ucred,
326 			      &eproc.e_ucred);
327 
328 		switch(what) {
329 
330 		case KERN_PROC_PID:
331 			if (proc.p_pid != (pid_t)arg)
332 				continue;
333 			break;
334 
335 		case KERN_PROC_UID:
336 			if (eproc.e_ucred.cr_uid != (uid_t)arg)
337 				continue;
338 			break;
339 
340 		case KERN_PROC_RUID:
341 			if (eproc.e_pcred.p_ruid != (uid_t)arg)
342 				continue;
343 			break;
344 		}
345 		/*
346 		 * We're going to add another proc to the set.  If this
347 		 * will overflow the buffer, assume the reason is because
348 		 * nprocs (or the proc list) is corrupt and declare an error.
349 		 */
350 		if (cnt >= maxcnt) {
351 			_kvm_err(kd, kd->program, "nprocs corrupt");
352 			return (-1);
353 		}
354 		/*
355 		 * gather eproc
356 		 */
357 		eproc.e_paddr = p;
358 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
359 			_kvm_err(kd, kd->program, "can't read pgrp at %x",
360 				 proc.p_pgrp);
361 			return (-1);
362 		}
363 		eproc.e_sess = pgrp.pg_session;
364 		eproc.e_pgid = pgrp.pg_id;
365 		eproc.e_jobc = pgrp.pg_jobc;
366 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
367 			_kvm_err(kd, kd->program, "can't read session at %x",
368 				pgrp.pg_session);
369 			return (-1);
370 		}
371 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
372 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
373 				_kvm_err(kd, kd->program,
374 					 "can't read tty at %x", sess.s_ttyp);
375 				return (-1);
376 			}
377 			eproc.e_tdev = tty.t_dev;
378 			eproc.e_tsess = tty.t_session;
379 			if (tty.t_pgrp != NULL) {
380 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
381 					_kvm_err(kd, kd->program,
382 						 "can't read tpgrp at &x",
383 						tty.t_pgrp);
384 					return (-1);
385 				}
386 				eproc.e_tpgid = pgrp.pg_id;
387 			} else
388 				eproc.e_tpgid = -1;
389 		} else
390 			eproc.e_tdev = NODEV;
391 		eproc.e_flag = sess.s_ttyvp ? EPROC_CTTY : 0;
392 		if (sess.s_leader == p)
393 			eproc.e_flag |= EPROC_SLEADER;
394 		if (proc.p_wmesg)
395 			(void)kvm_read(kd, (u_long)proc.p_wmesg,
396 			    eproc.e_wmesg, WMESGLEN);
397 
398 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
399 		    (char *)&eproc.e_vm, sizeof(eproc.e_vm));
400 
401 		eproc.e_xsize = eproc.e_xrssize = 0;
402 		eproc.e_xccount = eproc.e_xswrss = 0;
403 
404 		switch (what) {
405 
406 		case KERN_PROC_PGRP:
407 			if (eproc.e_pgid != (pid_t)arg)
408 				continue;
409 			break;
410 
411 		case KERN_PROC_TTY:
412 			if ((proc.p_flag & P_CONTROLT) == 0 ||
413 			     eproc.e_tdev != (dev_t)arg)
414 				continue;
415 			break;
416 		}
417 		bcopy(&proc, &bp->kp_proc, sizeof(proc));
418 		bcopy(&eproc, &bp->kp_eproc, sizeof(eproc));
419 		++bp;
420 		++cnt;
421 	}
422 	return (cnt);
423 }
424 
425 /*
426  * Build proc info array by reading in proc list from a crash dump.
427  * Return number of procs read.  maxcnt is the max we will read.
428  */
429 static int
430 kvm_deadprocs(kd, what, arg, a_allproc, a_zombproc, maxcnt)
431 	kvm_t *kd;
432 	int what, arg;
433 	u_long a_allproc;
434 	u_long a_zombproc;
435 	int maxcnt;
436 {
437 	register struct kinfo_proc *bp = kd->procbase;
438 	register int acnt, zcnt;
439 	struct proc *p;
440 
441 	if (KREAD(kd, a_allproc, &p)) {
442 		_kvm_err(kd, kd->program, "cannot read allproc");
443 		return (-1);
444 	}
445 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
446 	if (acnt < 0)
447 		return (acnt);
448 
449 	if (KREAD(kd, a_zombproc, &p)) {
450 		_kvm_err(kd, kd->program, "cannot read zombproc");
451 		return (-1);
452 	}
453 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
454 	if (zcnt < 0)
455 		zcnt = 0;
456 
457 	return (acnt + zcnt);
458 }
459 
460 struct kinfo_proc *
461 kvm_getprocs(kd, op, arg, cnt)
462 	kvm_t *kd;
463 	int op, arg;
464 	int *cnt;
465 {
466 	size_t size;
467 	int mib[4], st, nprocs;
468 
469 	if (kd->procbase != 0) {
470 		free((void *)kd->procbase);
471 		/*
472 		 * Clear this pointer in case this call fails.  Otherwise,
473 		 * kvm_close() will free it again.
474 		 */
475 		kd->procbase = 0;
476 	}
477 	if (ISALIVE(kd)) {
478 		size = 0;
479 		mib[0] = CTL_KERN;
480 		mib[1] = KERN_PROC;
481 		mib[2] = op;
482 		mib[3] = arg;
483 		st = sysctl(mib, 4, NULL, &size, NULL, 0);
484 		if (st == -1) {
485 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
486 			return (0);
487 		}
488 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
489 		if (kd->procbase == 0)
490 			return (0);
491 		st = sysctl(mib, 4, kd->procbase, &size, NULL, 0);
492 		if (st == -1) {
493 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
494 			return (0);
495 		}
496 		if (size % sizeof(struct kinfo_proc) != 0) {
497 			_kvm_err(kd, kd->program,
498 				"proc size mismatch (%d total, %d chunks)",
499 				size, sizeof(struct kinfo_proc));
500 			return (0);
501 		}
502 		nprocs = size / sizeof(struct kinfo_proc);
503 	} else {
504 		struct nlist nl[4], *p;
505 
506 		nl[0].n_name = "_nprocs";
507 		nl[1].n_name = "_allproc";
508 		nl[2].n_name = "_zombproc";
509 		nl[3].n_name = 0;
510 
511 		if (kvm_nlist(kd, nl) != 0) {
512 			for (p = nl; p->n_type != 0; ++p)
513 				;
514 			_kvm_err(kd, kd->program,
515 				 "%s: no such symbol", p->n_name);
516 			return (0);
517 		}
518 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
519 			_kvm_err(kd, kd->program, "can't read nprocs");
520 			return (0);
521 		}
522 		size = nprocs * sizeof(struct kinfo_proc);
523 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
524 		if (kd->procbase == 0)
525 			return (0);
526 
527 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
528 				      nl[2].n_value, nprocs);
529 #ifdef notdef
530 		size = nprocs * sizeof(struct kinfo_proc);
531 		(void)realloc(kd->procbase, size);
532 #endif
533 	}
534 	*cnt = nprocs;
535 	return (kd->procbase);
536 }
537 
538 void
539 _kvm_freeprocs(kd)
540 	kvm_t *kd;
541 {
542 	if (kd->procbase) {
543 		free(kd->procbase);
544 		kd->procbase = 0;
545 	}
546 }
547 
548 void *
549 _kvm_realloc(kd, p, n)
550 	kvm_t *kd;
551 	void *p;
552 	size_t n;
553 {
554 	void *np = (void *)realloc(p, n);
555 
556 	if (np == 0)
557 		_kvm_err(kd, kd->program, "out of memory");
558 	return (np);
559 }
560 
561 #ifndef MAX
562 #define MAX(a, b) ((a) > (b) ? (a) : (b))
563 #endif
564 
565 /*
566  * Read in an argument vector from the user address space of process p.
567  * addr if the user-space base address of narg null-terminated contiguous
568  * strings.  This is used to read in both the command arguments and
569  * environment strings.  Read at most maxcnt characters of strings.
570  */
571 static char **
572 kvm_argv(kd, p, addr, narg, maxcnt)
573 	kvm_t *kd;
574 	struct proc *p;
575 	register u_long addr;
576 	register int narg;
577 	register int maxcnt;
578 {
579 	register char *cp;
580 	register int len, cc;
581 	register char **argv;
582 
583 	/*
584 	 * Check that there aren't an unreasonable number of agruments,
585 	 * and that the address is in user space.
586 	 */
587 	if (narg > 512 || addr < VM_MIN_ADDRESS || addr >= VM_MAXUSER_ADDRESS)
588 		return (0);
589 
590 	if (kd->argv == 0) {
591 		/*
592 		 * Try to avoid reallocs.
593 		 */
594 		kd->argc = MAX(narg + 1, 32);
595 		kd->argv = (char **)_kvm_malloc(kd, kd->argc *
596 						sizeof(*kd->argv));
597 		if (kd->argv == 0)
598 			return (0);
599 	} else if (narg + 1 > kd->argc) {
600 		kd->argc = MAX(2 * kd->argc, narg + 1);
601 		kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
602 						sizeof(*kd->argv));
603 		if (kd->argv == 0)
604 			return (0);
605 	}
606 	if (kd->argspc == 0) {
607 		kd->argspc = (char *)_kvm_malloc(kd, kd->nbpg);
608 		if (kd->argspc == 0)
609 			return (0);
610 		kd->arglen = kd->nbpg;
611 	}
612 	cp = kd->argspc;
613 	argv = kd->argv;
614 	*argv = cp;
615 	len = 0;
616 	/*
617 	 * Loop over pages, filling in the argument vector.
618 	 */
619 	while (addr < VM_MAXUSER_ADDRESS) {
620 		cc = kd->nbpg - (addr & (kd->nbpg - 1));
621 		if (maxcnt > 0 && cc > maxcnt - len)
622 			cc = maxcnt - len;;
623 		if (len + cc > kd->arglen) {
624 			register int off;
625 			register char **pp;
626 			register char *op = kd->argspc;
627 
628 			kd->arglen *= 2;
629 			kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
630 							  kd->arglen);
631 			if (kd->argspc == 0)
632 				return (0);
633 			cp = &kd->argspc[len];
634 			/*
635 			 * Adjust argv pointers in case realloc moved
636 			 * the string space.
637 			 */
638 			off = kd->argspc - op;
639 			for (pp = kd->argv; pp < argv; ++pp)
640 				*pp += off;
641 		}
642 		if (kvm_uread(kd, p, addr, cp, cc) != cc)
643 			/* XXX */
644 			return (0);
645 		len += cc;
646 		addr += cc;
647 
648 		if (maxcnt == 0 && len > 16 * kd->nbpg)
649 			/* sanity */
650 			return (0);
651 
652 		while (--cc >= 0) {
653 			if (*cp++ == 0) {
654 				if (--narg <= 0) {
655 					*++argv = 0;
656 					return (kd->argv);
657 				} else
658 					*++argv = cp;
659 			}
660 		}
661 		if (maxcnt > 0 && len >= maxcnt) {
662 			/*
663 			 * We're stopping prematurely.  Terminate the
664 			 * argv and current string.
665 			 */
666 			*++argv = 0;
667 			*cp = 0;
668 			return (kd->argv);
669 		}
670 	}
671 }
672 
673 static void
674 ps_str_a(p, addr, n)
675 	struct ps_strings *p;
676 	u_long *addr;
677 	int *n;
678 {
679 	*addr = (u_long)p->ps_argvstr;
680 	*n = p->ps_nargvstr;
681 }
682 
683 static void
684 ps_str_e(p, addr, n)
685 	struct ps_strings *p;
686 	u_long *addr;
687 	int *n;
688 {
689 	*addr = (u_long)p->ps_envstr;
690 	*n = p->ps_nenvstr;
691 }
692 
693 /*
694  * Determine if the proc indicated by p is still active.
695  * This test is not 100% foolproof in theory, but chances of
696  * being wrong are very low.
697  */
698 static int
699 proc_verify(kd, kernp, p)
700 	kvm_t *kd;
701 	u_long kernp;
702 	const struct proc *p;
703 {
704 	struct proc kernproc;
705 
706 	/*
707 	 * Just read in the whole proc.  It's not that big relative
708 	 * to the cost of the read system call.
709 	 */
710 	if (kvm_read(kd, kernp, (char *)&kernproc, sizeof(kernproc)) !=
711 	    sizeof(kernproc))
712 		return (0);
713 	return (p->p_pid == kernproc.p_pid &&
714 		(kernproc.p_stat != SZOMB || p->p_stat == SZOMB));
715 }
716 
717 static char **
718 kvm_doargv(kd, kp, nchr, info)
719 	kvm_t *kd;
720 	const struct kinfo_proc *kp;
721 	int nchr;
722 	int (*info)(struct ps_strings*, u_long *, int *);
723 {
724 	register const struct proc *p = &kp->kp_proc;
725 	register char **ap;
726 	u_long addr;
727 	int cnt;
728 	struct ps_strings arginfo;
729 
730 	/*
731 	 * Pointers are stored at the top of the user stack.
732 	 */
733 	if (p->p_stat == SZOMB ||
734 	    kvm_uread(kd, p, USRSTACK - sizeof(arginfo), (char *)&arginfo,
735 		      sizeof(arginfo)) != sizeof(arginfo))
736 		return (0);
737 
738 	(*info)(&arginfo, &addr, &cnt);
739 	if (cnt == 0)
740 		return (0);
741 	ap = kvm_argv(kd, p, addr, cnt, nchr);
742 	/*
743 	 * For live kernels, make sure this process didn't go away.
744 	 */
745 	if (ap != 0 && ISALIVE(kd) &&
746 	    !proc_verify(kd, (u_long)kp->kp_eproc.e_paddr, p))
747 		ap = 0;
748 	return (ap);
749 }
750 
751 /*
752  * Get the command args.  This code is now machine independent.
753  */
754 char **
755 kvm_getargv(kd, kp, nchr)
756 	kvm_t *kd;
757 	const struct kinfo_proc *kp;
758 	int nchr;
759 {
760 	return (kvm_doargv(kd, kp, nchr, ps_str_a));
761 }
762 
763 char **
764 kvm_getenvv(kd, kp, nchr)
765 	kvm_t *kd;
766 	const struct kinfo_proc *kp;
767 	int nchr;
768 {
769 	return (kvm_doargv(kd, kp, nchr, ps_str_e));
770 }
771 
772 /*
773  * Read from user space.  The user context is given by p.
774  */
775 ssize_t
776 kvm_uread(kd, p, uva, buf, len)
777 	kvm_t *kd;
778 	register const struct proc *p;
779 	register u_long uva;
780 	register char *buf;
781 	register size_t len;
782 {
783 	register char *cp;
784 
785 	cp = buf;
786 	while (len > 0) {
787 		register int cc;
788 		register char *dp;
789 		int cnt;
790 
791 		dp = _kvm_uread(kd, p, uva, &cnt);
792 		if (dp == 0) {
793 			_kvm_err(kd, 0, "invalid address (%x)", uva);
794 			return (0);
795 		}
796 		cc = MIN(cnt, len);
797 		bcopy(dp, cp, cc);
798 
799 		cp += cc;
800 		uva += cc;
801 		len -= cc;
802 	}
803 	return (ssize_t)(cp - buf);
804 }
805