xref: /openbsd-src/lib/libkvm/kvm_proc.c (revision ce7e0fc6a9d74d25b78fb6ad846387717f5172b6)
1 /*	$OpenBSD: kvm_proc.c,v 1.14 2002/02/17 19:42:25 millert Exp $	*/
2 /*	$NetBSD: kvm_proc.c,v 1.30 1999/03/24 05:50:50 mrg Exp $	*/
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  * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
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 #if defined(LIBC_SCCS) && !defined(lint)
77 #if 0
78 static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
79 #else
80 static char *rcsid = "$OpenBSD: kvm_proc.c,v 1.14 2002/02/17 19:42:25 millert Exp $";
81 #endif
82 #endif /* LIBC_SCCS and not lint */
83 
84 /*
85  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
86  * users of this code, so we've factored it out into a separate module.
87  * Thus, we keep this grunge out of the other kvm applications (i.e.,
88  * most other applications are interested only in open/close/read/nlist).
89  */
90 
91 #include <sys/param.h>
92 #include <sys/user.h>
93 #include <sys/proc.h>
94 #include <sys/exec.h>
95 #include <sys/stat.h>
96 #include <sys/ioctl.h>
97 #include <sys/tty.h>
98 #include <stdlib.h>
99 #include <string.h>
100 #include <unistd.h>
101 #include <nlist.h>
102 #include <kvm.h>
103 
104 #include <uvm/uvm_extern.h>
105 #include <uvm/uvm_amap.h>
106 #include <machine/vmparam.h>
107 #include <machine/pmap.h>
108 
109 #include <sys/sysctl.h>
110 
111 #include <limits.h>
112 #include <db.h>
113 #include <paths.h>
114 
115 #include "kvm_private.h"
116 
117 #define KREAD(kd, addr, obj) \
118 	(kvm_read(kd, addr, (void *)(obj), sizeof(*obj)) != sizeof(*obj))
119 
120 ssize_t		kvm_uread(kvm_t *, const struct proc *, u_long, char *, size_t);
121 
122 static char	**kvm_argv(kvm_t *, const struct proc *, u_long, int, int);
123 static int	kvm_deadprocs(kvm_t *, int, int, u_long, u_long, int);
124 static char	**kvm_doargv(kvm_t *, const struct kinfo_proc *, int,
125 		    void (*)(struct ps_strings *, u_long *, int *));
126 static int	kvm_proclist(kvm_t *, int, int, struct proc *,
127 		    struct kinfo_proc *, int);
128 static int	proc_verify(kvm_t *, u_long, const struct proc *);
129 static void	ps_str_a(struct ps_strings *, u_long *, int *);
130 static void	ps_str_e(struct ps_strings *, u_long *, int *);
131 
132 char *
133 _kvm_uread(kd, p, va, cnt)
134 	kvm_t *kd;
135 	const struct proc *p;
136 	u_long va;
137 	u_long *cnt;
138 {
139 	u_long addr, head;
140 	u_long offset;
141 	struct vm_map_entry vme;
142 	struct vm_amap amap;
143 	struct vm_anon *anonp, anon;
144 	struct vm_page pg;
145 	u_long slot;
146 
147 	if (kd->swapspc == 0) {
148 		kd->swapspc = (char *)_kvm_malloc(kd, kd->nbpg);
149 		if (kd->swapspc == 0)
150 			return (0);
151 	}
152 
153 	/*
154 	 * Look through the address map for the memory object
155 	 * that corresponds to the given virtual address.
156 	 * The header just has the entire valid range.
157 	 */
158 	head = (u_long)&p->p_vmspace->vm_map.header;
159 	addr = head;
160 	while (1) {
161 		if (KREAD(kd, addr, &vme))
162 			return (0);
163 
164 		if (va >= vme.start && va < vme.end &&
165 		    vme.aref.ar_amap != NULL)
166 			break;
167 
168 		addr = (u_long)vme.next;
169 		if (addr == head)
170 			return (0);
171 	}
172 
173 	/*
174 	 * we found the map entry, now to find the object...
175 	 */
176 	if (vme.aref.ar_amap == NULL)
177 		return NULL;
178 
179 	addr = (u_long)vme.aref.ar_amap;
180 	if (KREAD(kd, addr, &amap))
181 		return NULL;
182 
183 	offset = va - vme.start;
184 	slot = offset / kd->nbpg + vme.aref.ar_pageoff;
185 	/* sanity-check slot number */
186 	if (slot > amap.am_nslot)
187 		return NULL;
188 
189 	addr = (u_long)amap.am_anon + (offset / kd->nbpg) * sizeof(anonp);
190 	if (KREAD(kd, addr, &anonp))
191 		return NULL;
192 
193 	addr = (u_long)anonp;
194 	if (KREAD(kd, addr, &anon))
195 		return NULL;
196 
197 	addr = (u_long)anon.u.an_page;
198 	if (addr) {
199 		if (KREAD(kd, addr, &pg))
200 			return NULL;
201 
202 		if (_kvm_pread(kd, kd->pmfd, (void *)kd->swapspc, (size_t)kd->nbpg, (off_t)pg.phys_addr) != kd->nbpg) {
203 			return NULL;
204 		}
205 	} else {
206 		if (_kvm_pread(kd, kd->swfd, (void *)kd->swapspc, (size_t)kd->nbpg, (off_t)(anon.an_swslot * kd->nbpg)) != kd->nbpg) {
207 			return NULL;
208 		}
209 	}
210 
211 	/* Found the page. */
212 	offset %= kd->nbpg;
213 	*cnt = kd->nbpg - offset;
214 	return (&kd->swapspc[offset]);
215 }
216 
217 /*
218  * Read proc's from memory file into buffer bp, which has space to hold
219  * at most maxcnt procs.
220  */
221 static int
222 kvm_proclist(kd, what, arg, p, bp, maxcnt)
223 	kvm_t *kd;
224 	int what, arg;
225 	struct proc *p;
226 	struct kinfo_proc *bp;
227 	int maxcnt;
228 {
229 	int cnt = 0;
230 	struct eproc eproc;
231 	struct pgrp pgrp;
232 	struct session sess;
233 	struct tty tty;
234 	struct proc proc;
235 
236 	for (; cnt < maxcnt && p != NULL; p = proc.p_list.le_next) {
237 		if (KREAD(kd, (u_long)p, &proc)) {
238 			_kvm_err(kd, kd->program, "can't read proc at %x", p);
239 			return (-1);
240 		}
241 		if (KREAD(kd, (u_long)proc.p_cred, &eproc.e_pcred) == 0)
242 			KREAD(kd, (u_long)eproc.e_pcred.pc_ucred,
243 			      &eproc.e_ucred);
244 
245 		switch(what) {
246 
247 		case KERN_PROC_PID:
248 			if (proc.p_pid != (pid_t)arg)
249 				continue;
250 			break;
251 
252 		case KERN_PROC_UID:
253 			if (eproc.e_ucred.cr_uid != (uid_t)arg)
254 				continue;
255 			break;
256 
257 		case KERN_PROC_RUID:
258 			if (eproc.e_pcred.p_ruid != (uid_t)arg)
259 				continue;
260 			break;
261 
262 		case KERN_PROC_ALL:
263 			if (proc.p_flag & P_SYSTEM)
264 				continue;
265 			break;
266 		}
267 		/*
268 		 * We're going to add another proc to the set.  If this
269 		 * will overflow the buffer, assume the reason is because
270 		 * nprocs (or the proc list) is corrupt and declare an error.
271 		 */
272 		if (cnt >= maxcnt) {
273 			_kvm_err(kd, kd->program, "nprocs corrupt");
274 			return (-1);
275 		}
276 		/*
277 		 * gather eproc
278 		 */
279 		eproc.e_paddr = p;
280 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
281 			_kvm_err(kd, kd->program, "can't read pgrp at %x",
282 				 proc.p_pgrp);
283 			return (-1);
284 		}
285 		eproc.e_sess = pgrp.pg_session;
286 		eproc.e_pgid = pgrp.pg_id;
287 		eproc.e_jobc = pgrp.pg_jobc;
288 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
289 			_kvm_err(kd, kd->program, "can't read session at %x",
290 				pgrp.pg_session);
291 			return (-1);
292 		}
293 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
294 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
295 				_kvm_err(kd, kd->program,
296 					 "can't read tty at %x", sess.s_ttyp);
297 				return (-1);
298 			}
299 			eproc.e_tdev = tty.t_dev;
300 			eproc.e_tsess = tty.t_session;
301 			if (tty.t_pgrp != NULL) {
302 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
303 					_kvm_err(kd, kd->program,
304 						 "can't read tpgrp at &x",
305 						tty.t_pgrp);
306 					return (-1);
307 				}
308 				eproc.e_tpgid = pgrp.pg_id;
309 			} else
310 				eproc.e_tpgid = -1;
311 		} else
312 			eproc.e_tdev = NODEV;
313 		eproc.e_flag = sess.s_ttyvp ? EPROC_CTTY : 0;
314 		if (sess.s_leader == p)
315 			eproc.e_flag |= EPROC_SLEADER;
316 		if (proc.p_wmesg)
317 			(void)kvm_read(kd, (u_long)proc.p_wmesg,
318 			    eproc.e_wmesg, WMESGLEN);
319 
320 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
321 		    &eproc.e_vm, sizeof(eproc.e_vm));
322 
323 		eproc.e_xsize = eproc.e_xrssize = 0;
324 		eproc.e_xccount = eproc.e_xswrss = 0;
325 
326 		switch (what) {
327 
328 		case KERN_PROC_PGRP:
329 			if (eproc.e_pgid != (pid_t)arg)
330 				continue;
331 			break;
332 
333 		case KERN_PROC_TTY:
334 			if ((proc.p_flag & P_CONTROLT) == 0 ||
335 			     eproc.e_tdev != (dev_t)arg)
336 				continue;
337 			break;
338 		}
339 		bcopy(&proc, &bp->kp_proc, sizeof(proc));
340 		bcopy(&eproc, &bp->kp_eproc, sizeof(eproc));
341 		++bp;
342 		++cnt;
343 	}
344 	return (cnt);
345 }
346 
347 /*
348  * Build proc info array by reading in proc list from a crash dump.
349  * Return number of procs read.  maxcnt is the max we will read.
350  */
351 static int
352 kvm_deadprocs(kd, what, arg, a_allproc, a_zombproc, maxcnt)
353 	kvm_t *kd;
354 	int what, arg;
355 	u_long a_allproc;
356 	u_long a_zombproc;
357 	int maxcnt;
358 {
359 	struct kinfo_proc *bp = kd->procbase;
360 	int acnt, zcnt;
361 	struct proc *p;
362 
363 	if (KREAD(kd, a_allproc, &p)) {
364 		_kvm_err(kd, kd->program, "cannot read allproc");
365 		return (-1);
366 	}
367 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
368 	if (acnt < 0)
369 		return (acnt);
370 
371 	if (KREAD(kd, a_zombproc, &p)) {
372 		_kvm_err(kd, kd->program, "cannot read zombproc");
373 		return (-1);
374 	}
375 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
376 	if (zcnt < 0)
377 		zcnt = 0;
378 
379 	return (acnt + zcnt);
380 }
381 
382 struct kinfo_proc *
383 kvm_getprocs(kd, op, arg, cnt)
384 	kvm_t *kd;
385 	int op, arg;
386 	int *cnt;
387 {
388 	size_t size;
389 	int mib[4], st, nprocs;
390 
391 	if (kd->procbase != 0) {
392 		free((void *)kd->procbase);
393 		/*
394 		 * Clear this pointer in case this call fails.  Otherwise,
395 		 * kvm_close() will free it again.
396 		 */
397 		kd->procbase = 0;
398 	}
399 	if (ISALIVE(kd)) {
400 		size = 0;
401 		mib[0] = CTL_KERN;
402 		mib[1] = KERN_PROC;
403 		mib[2] = op;
404 		mib[3] = arg;
405 		st = sysctl(mib, 4, NULL, &size, NULL, 0);
406 		if (st == -1) {
407 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
408 			return (0);
409 		}
410 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
411 		if (kd->procbase == 0)
412 			return (0);
413 		st = sysctl(mib, 4, kd->procbase, &size, NULL, 0);
414 		if (st == -1) {
415 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
416 			return (0);
417 		}
418 		if (size % sizeof(struct kinfo_proc) != 0) {
419 			_kvm_err(kd, kd->program,
420 				"proc size mismatch (%d total, %d chunks)",
421 				size, sizeof(struct kinfo_proc));
422 			return (0);
423 		}
424 		nprocs = size / sizeof(struct kinfo_proc);
425 	} else {
426 		struct nlist nl[4], *p;
427 
428 		nl[0].n_name = "_nprocs";
429 		nl[1].n_name = "_allproc";
430 		nl[2].n_name = "_zombproc";
431 		nl[3].n_name = 0;
432 
433 		if (kvm_nlist(kd, nl) != 0) {
434 			for (p = nl; p->n_type != 0; ++p)
435 				;
436 			_kvm_err(kd, kd->program,
437 				 "%s: no such symbol", p->n_name);
438 			return (0);
439 		}
440 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
441 			_kvm_err(kd, kd->program, "can't read nprocs");
442 			return (0);
443 		}
444 		size = nprocs * sizeof(struct kinfo_proc);
445 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
446 		if (kd->procbase == 0)
447 			return (0);
448 
449 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
450 				      nl[2].n_value, nprocs);
451 #ifdef notdef
452 		size = nprocs * sizeof(struct kinfo_proc);
453 		(void)realloc(kd->procbase, size);
454 #endif
455 	}
456 	*cnt = nprocs;
457 	return (kd->procbase);
458 }
459 
460 void
461 _kvm_freeprocs(kd)
462 	kvm_t *kd;
463 {
464 	if (kd->procbase) {
465 		free(kd->procbase);
466 		kd->procbase = 0;
467 	}
468 }
469 
470 void *
471 _kvm_realloc(kd, p, n)
472 	kvm_t *kd;
473 	void *p;
474 	size_t n;
475 {
476 	void *np = (void *)realloc(p, n);
477 
478 	if (np == 0)
479 		_kvm_err(kd, kd->program, "out of memory");
480 	return (np);
481 }
482 
483 #ifndef MAX
484 #define MAX(a, b) ((a) > (b) ? (a) : (b))
485 #endif
486 
487 /*
488  * Read in an argument vector from the user address space of process p.
489  * addr if the user-space base address of narg null-terminated contiguous
490  * strings.  This is used to read in both the command arguments and
491  * environment strings.  Read at most maxcnt characters of strings.
492  */
493 static char **
494 kvm_argv(kd, p, addr, narg, maxcnt)
495 	kvm_t *kd;
496 	const struct proc *p;
497 	u_long addr;
498 	int narg;
499 	int maxcnt;
500 {
501 	char *np, *cp, *ep, *ap;
502 	u_long oaddr = -1;
503 	int len, cc;
504 	char **argv;
505 
506 	/*
507 	 * Check that there aren't an unreasonable number of agruments,
508 	 * and that the address is in user space.
509 	 */
510 	if (narg > ARG_MAX || addr < VM_MIN_ADDRESS || addr >= VM_MAXUSER_ADDRESS)
511 		return (0);
512 
513 	if (kd->argv == 0) {
514 		/*
515 		 * Try to avoid reallocs.
516 		 */
517 		kd->argc = MAX(narg + 1, 32);
518 		kd->argv = (char **)_kvm_malloc(kd, kd->argc *
519 						sizeof(*kd->argv));
520 		if (kd->argv == 0)
521 			return (0);
522 	} else if (narg + 1 > kd->argc) {
523 		kd->argc = MAX(2 * kd->argc, narg + 1);
524 		kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
525 						sizeof(*kd->argv));
526 		if (kd->argv == 0)
527 			return (0);
528 	}
529 	if (kd->argspc == 0) {
530 		kd->argspc = (char *)_kvm_malloc(kd, kd->nbpg);
531 		if (kd->argspc == 0)
532 			return (0);
533 		kd->arglen = kd->nbpg;
534 	}
535 	if (kd->argbuf == 0) {
536 		kd->argbuf = (char *)_kvm_malloc(kd, kd->nbpg);
537 		if (kd->argbuf == 0)
538 			return (0);
539 	}
540 	cc = sizeof(char *) * narg;
541 	if (kvm_uread(kd, p, addr, (char *)kd->argv, cc) != cc)
542 		return (0);
543 	ap = np = kd->argspc;
544 	argv = kd->argv;
545 	len = 0;
546 	/*
547 	 * Loop over pages, filling in the argument vector.
548 	 */
549 	while (argv < kd->argv + narg && *argv != 0) {
550 		addr = (u_long)*argv & ~(kd->nbpg - 1);
551 		if (addr != oaddr) {
552 			if (kvm_uread(kd, p, addr, kd->argbuf, kd->nbpg) !=
553 			    kd->nbpg)
554 				return (0);
555 			oaddr = addr;
556 		}
557 		addr = (u_long)*argv & (kd->nbpg - 1);
558 		cp = kd->argbuf + addr;
559 		cc = kd->nbpg - addr;
560 		if (maxcnt > 0 && cc > maxcnt - len)
561 			cc = maxcnt - len;;
562 		ep = memchr(cp, '\0', cc);
563 		if (ep != 0)
564 			cc = ep - cp + 1;
565 		if (len + cc > kd->arglen) {
566 			int off;
567 			char **pp;
568 			char *op = kd->argspc;
569 
570 			kd->arglen *= 2;
571 			kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
572 							  kd->arglen);
573 			if (kd->argspc == 0)
574 				return (0);
575 			/*
576 			 * Adjust argv pointers in case realloc moved
577 			 * the string space.
578 			 */
579 			off = kd->argspc - op;
580 			for (pp = kd->argv; pp < argv; pp++)
581 				*pp += off;
582 			ap += off;
583 			np += off;
584 		}
585 		memcpy(np, cp, cc);
586 		np += cc;
587 		len += cc;
588 		if (ep != 0) {
589 			*argv++ = ap;
590 			ap = np;
591 		} else
592 			*argv += cc;
593 		if (maxcnt > 0 && len >= maxcnt) {
594 			/*
595 			 * We're stopping prematurely.  Terminate the
596 			 * current string.
597 			 */
598 			if (ep == 0) {
599 				*np = '\0';
600 				*argv++ = ap;
601 			}
602 			break;
603 		}
604 	}
605 	/* Make sure argv is terminated. */
606 	*argv = 0;
607 	return (kd->argv);
608 }
609 
610 static void
611 ps_str_a(p, addr, n)
612 	struct ps_strings *p;
613 	u_long *addr;
614 	int *n;
615 {
616 	*addr = (u_long)p->ps_argvstr;
617 	*n = p->ps_nargvstr;
618 }
619 
620 static void
621 ps_str_e(p, addr, n)
622 	struct ps_strings *p;
623 	u_long *addr;
624 	int *n;
625 {
626 	*addr = (u_long)p->ps_envstr;
627 	*n = p->ps_nenvstr;
628 }
629 
630 /*
631  * Determine if the proc indicated by p is still active.
632  * This test is not 100% foolproof in theory, but chances of
633  * being wrong are very low.
634  */
635 static int
636 proc_verify(kd, kernp, p)
637 	kvm_t *kd;
638 	u_long kernp;
639 	const struct proc *p;
640 {
641 	struct proc kernproc;
642 
643 	/*
644 	 * Just read in the whole proc.  It's not that big relative
645 	 * to the cost of the read system call.
646 	 */
647 	if (kvm_read(kd, kernp, &kernproc, sizeof(kernproc)) !=
648 	    sizeof(kernproc))
649 		return (0);
650 	return (p->p_pid == kernproc.p_pid &&
651 		(kernproc.p_stat != SZOMB || p->p_stat == SZOMB));
652 }
653 
654 static char **
655 kvm_doargv(kd, kp, nchr, info)
656 	kvm_t *kd;
657 	const struct kinfo_proc *kp;
658 	int nchr;
659 	void (*info)(struct ps_strings *, u_long *, int *);
660 {
661 	const struct proc *p = &kp->kp_proc;
662 	char **ap;
663 	u_long addr;
664 	int cnt;
665 	struct ps_strings arginfo;
666 	static struct ps_strings *ps;
667 
668 	if (ps == NULL) {
669 		struct _ps_strings _ps;
670 		int mib[2];
671 		size_t len;
672 
673 		mib[0] = CTL_VM;
674 		mib[1] = VM_PSSTRINGS;
675 		len = sizeof(_ps);
676 		sysctl(mib, 2, &_ps, &len, NULL, 0);
677 		ps = (struct ps_strings *)_ps.val;
678 	}
679 
680 	/*
681 	 * Pointers are stored at the top of the user stack.
682 	 */
683 	if (p->p_stat == SZOMB ||
684 	    kvm_uread(kd, p, (u_long)ps, (char *)&arginfo,
685 		      sizeof(arginfo)) != sizeof(arginfo))
686 		return (0);
687 
688 	(*info)(&arginfo, &addr, &cnt);
689 	if (cnt == 0)
690 		return (0);
691 	ap = kvm_argv(kd, p, addr, cnt, nchr);
692 	/*
693 	 * For live kernels, make sure this process didn't go away.
694 	 */
695 	if (ap != 0 && ISALIVE(kd) &&
696 	    !proc_verify(kd, (u_long)kp->kp_eproc.e_paddr, p))
697 		ap = 0;
698 	return (ap);
699 }
700 
701 /*
702  * Get the command args.  This code is now machine independent.
703  */
704 char **
705 kvm_getargv(kd, kp, nchr)
706 	kvm_t *kd;
707 	const struct kinfo_proc *kp;
708 	int nchr;
709 {
710 	return (kvm_doargv(kd, kp, nchr, ps_str_a));
711 }
712 
713 char **
714 kvm_getenvv(kd, kp, nchr)
715 	kvm_t *kd;
716 	const struct kinfo_proc *kp;
717 	int nchr;
718 {
719 	return (kvm_doargv(kd, kp, nchr, ps_str_e));
720 }
721 
722 /*
723  * Read from user space.  The user context is given by p.
724  */
725 ssize_t
726 kvm_uread(kd, p, uva, buf, len)
727 	kvm_t *kd;
728 	const struct proc *p;
729 	u_long uva;
730 	char *buf;
731 	size_t len;
732 {
733 	char *cp;
734 
735 	cp = buf;
736 	while (len > 0) {
737 		int cc;
738 		char *dp;
739 		u_long cnt;
740 
741 		dp = _kvm_uread(kd, p, uva, &cnt);
742 		if (dp == 0) {
743 			_kvm_err(kd, 0, "invalid address (%lx)", uva);
744 			return (0);
745 		}
746 		cc = MIN(cnt, len);
747 		bcopy(dp, cp, cc);
748 
749 		cp += cc;
750 		uva += cc;
751 		len -= cc;
752 	}
753 	return (ssize_t)(cp - buf);
754 }
755