xref: /freebsd/lib/libkvm/kvm_proc.c (revision 5129159789cc9d7bc514e4546b88e3427695002d)
1 /*-
2  * Copyright (c) 1989, 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software developed by the Computer Systems
6  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
7  * BG 91-66 and contributed to Berkeley.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by the University of
20  *	California, Berkeley and its contributors.
21  * 4. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  * $FreeBSD$
38  */
39 
40 #if defined(LIBC_SCCS) && !defined(lint)
41 static char sccsid[] = "@(#)kvm_proc.c	8.3 (Berkeley) 9/23/93";
42 #endif /* LIBC_SCCS and not lint */
43 
44 /*
45  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
46  * users of this code, so we've factored it out into a separate module.
47  * Thus, we keep this grunge out of the other kvm applications (i.e.,
48  * most other applications are interested only in open/close/read/nlist).
49  */
50 
51 #include <sys/param.h>
52 #include <sys/user.h>
53 #include <sys/proc.h>
54 #include <sys/exec.h>
55 #include <sys/stat.h>
56 #include <sys/ioctl.h>
57 #include <sys/tty.h>
58 #include <sys/file.h>
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <unistd.h>
62 #include <nlist.h>
63 #include <kvm.h>
64 
65 #include <vm/vm.h>
66 #include <vm/vm_param.h>
67 #include <vm/swap_pager.h>
68 
69 #include <sys/sysctl.h>
70 
71 #include <limits.h>
72 #include <memory.h>
73 #include <db.h>
74 #include <paths.h>
75 
76 #include "kvm_private.h"
77 
78 #if used
79 static char *
80 kvm_readswap(kd, p, va, cnt)
81 	kvm_t *kd;
82 	const struct proc *p;
83 	u_long va;
84 	u_long *cnt;
85 {
86 #ifdef __FreeBSD__
87 	/* XXX Stubbed out, our vm system is differnet */
88 	_kvm_err(kd, kd->program, "kvm_readswap not implemented");
89 	return(0);
90 #endif	/* __FreeBSD__ */
91 }
92 #endif
93 
94 #define KREAD(kd, addr, obj) \
95 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
96 
97 /*
98  * Read proc's from memory file into buffer bp, which has space to hold
99  * at most maxcnt procs.
100  */
101 static int
102 kvm_proclist(kd, what, arg, p, bp, maxcnt)
103 	kvm_t *kd;
104 	int what, arg;
105 	struct proc *p;
106 	struct kinfo_proc *bp;
107 	int maxcnt;
108 {
109 	register int cnt = 0;
110 	struct eproc eproc;
111 	struct pgrp pgrp;
112 	struct session sess;
113 	struct tty tty;
114 	struct proc proc;
115 	struct proc pproc;
116 
117 	for (; cnt < maxcnt && p != NULL; p = proc.p_list.le_next) {
118 		if (KREAD(kd, (u_long)p, &proc)) {
119 			_kvm_err(kd, kd->program, "can't read proc at %x", p);
120 			return (-1);
121 		}
122 		if (KREAD(kd, (u_long)proc.p_cred, &eproc.e_pcred) == 0)
123 			(void)(KREAD(kd, (u_long)eproc.e_pcred.pc_ucred,
124 			             &eproc.e_ucred));
125 
126 		switch(what) {
127 
128 		case KERN_PROC_PID:
129 			if (proc.p_pid != (pid_t)arg)
130 				continue;
131 			break;
132 
133 		case KERN_PROC_UID:
134 			if (eproc.e_ucred.cr_uid != (uid_t)arg)
135 				continue;
136 			break;
137 
138 		case KERN_PROC_RUID:
139 			if (eproc.e_pcred.p_ruid != (uid_t)arg)
140 				continue;
141 			break;
142 		}
143 		/*
144 		 * We're going to add another proc to the set.  If this
145 		 * will overflow the buffer, assume the reason is because
146 		 * nprocs (or the proc list) is corrupt and declare an error.
147 		 */
148 		if (cnt >= maxcnt) {
149 			_kvm_err(kd, kd->program, "nprocs corrupt");
150 			return (-1);
151 		}
152 		/*
153 		 * gather eproc
154 		 */
155 		eproc.e_paddr = p;
156 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
157 			_kvm_err(kd, kd->program, "can't read pgrp at %x",
158 				 proc.p_pgrp);
159 			return (-1);
160 		}
161 		if (proc.p_oppid)
162 		  eproc.e_ppid = proc.p_oppid;
163 		else if (proc.p_pptr) {
164 		  if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
165 			_kvm_err(kd, kd->program, "can't read pproc at %x",
166 				 proc.p_pptr);
167 			return (-1);
168 		  }
169 		  eproc.e_ppid = pproc.p_pid;
170 		} else
171 		  eproc.e_ppid = 0;
172 		eproc.e_sess = pgrp.pg_session;
173 		eproc.e_pgid = pgrp.pg_id;
174 		eproc.e_jobc = pgrp.pg_jobc;
175 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
176 			_kvm_err(kd, kd->program, "can't read session at %x",
177 				pgrp.pg_session);
178 			return (-1);
179 		}
180 		(void)memcpy(eproc.e_login, sess.s_login,
181 						sizeof(eproc.e_login));
182 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
183 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
184 				_kvm_err(kd, kd->program,
185 					 "can't read tty at %x", sess.s_ttyp);
186 				return (-1);
187 			}
188 			eproc.e_tdev = tty.t_dev;
189 			eproc.e_tsess = tty.t_session;
190 			if (tty.t_pgrp != NULL) {
191 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
192 					_kvm_err(kd, kd->program,
193 						 "can't read tpgrp at &x",
194 						tty.t_pgrp);
195 					return (-1);
196 				}
197 				eproc.e_tpgid = pgrp.pg_id;
198 			} else
199 				eproc.e_tpgid = -1;
200 		} else
201 			eproc.e_tdev = NODEV;
202 		eproc.e_flag = sess.s_ttyvp ? EPROC_CTTY : 0;
203 		if (sess.s_leader == p)
204 			eproc.e_flag |= EPROC_SLEADER;
205 		if (proc.p_wmesg)
206 			(void)kvm_read(kd, (u_long)proc.p_wmesg,
207 			    eproc.e_wmesg, WMESGLEN);
208 
209 #ifdef sparc
210 		(void)kvm_read(kd, (u_long)&proc.p_vmspace->vm_rssize,
211 		    (char *)&eproc.e_vm.vm_rssize,
212 		    sizeof(eproc.e_vm.vm_rssize));
213 		(void)kvm_read(kd, (u_long)&proc.p_vmspace->vm_tsize,
214 		    (char *)&eproc.e_vm.vm_tsize,
215 		    3 * sizeof(eproc.e_vm.vm_rssize));	/* XXX */
216 #else
217 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
218 		    (char *)&eproc.e_vm, sizeof(eproc.e_vm));
219 #endif
220 		eproc.e_xsize = eproc.e_xrssize = 0;
221 		eproc.e_xccount = eproc.e_xswrss = 0;
222 
223 		switch (what) {
224 
225 		case KERN_PROC_PGRP:
226 			if (eproc.e_pgid != (pid_t)arg)
227 				continue;
228 			break;
229 
230 		case KERN_PROC_TTY:
231 			if ((proc.p_flag & P_CONTROLT) == 0 ||
232 			     eproc.e_tdev != (dev_t)arg)
233 				continue;
234 			break;
235 		}
236 		bcopy(&proc, &bp->kp_proc, sizeof(proc));
237 		bcopy(&eproc, &bp->kp_eproc, sizeof(eproc));
238 		++bp;
239 		++cnt;
240 	}
241 	return (cnt);
242 }
243 
244 /*
245  * Build proc info array by reading in proc list from a crash dump.
246  * Return number of procs read.  maxcnt is the max we will read.
247  */
248 static int
249 kvm_deadprocs(kd, what, arg, a_allproc, a_zombproc, maxcnt)
250 	kvm_t *kd;
251 	int what, arg;
252 	u_long a_allproc;
253 	u_long a_zombproc;
254 	int maxcnt;
255 {
256 	register struct kinfo_proc *bp = kd->procbase;
257 	register int acnt, zcnt;
258 	struct proc *p;
259 
260 	if (KREAD(kd, a_allproc, &p)) {
261 		_kvm_err(kd, kd->program, "cannot read allproc");
262 		return (-1);
263 	}
264 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
265 	if (acnt < 0)
266 		return (acnt);
267 
268 	if (KREAD(kd, a_zombproc, &p)) {
269 		_kvm_err(kd, kd->program, "cannot read zombproc");
270 		return (-1);
271 	}
272 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
273 	if (zcnt < 0)
274 		zcnt = 0;
275 
276 	return (acnt + zcnt);
277 }
278 
279 struct kinfo_proc *
280 kvm_getprocs(kd, op, arg, cnt)
281 	kvm_t *kd;
282 	int op, arg;
283 	int *cnt;
284 {
285 	int mib[4], st, nprocs;
286 	size_t size;
287 
288 	if (kd->procbase != 0) {
289 		free((void *)kd->procbase);
290 		/*
291 		 * Clear this pointer in case this call fails.  Otherwise,
292 		 * kvm_close() will free it again.
293 		 */
294 		kd->procbase = 0;
295 	}
296 	if (ISALIVE(kd)) {
297 		size = 0;
298 		mib[0] = CTL_KERN;
299 		mib[1] = KERN_PROC;
300 		mib[2] = op;
301 		mib[3] = arg;
302 		st = sysctl(mib, op == KERN_PROC_ALL ? 3 : 4, NULL, &size, NULL, 0);
303 		if (st == -1) {
304 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
305 			return (0);
306 		}
307 		do {
308 			size += size / 10;
309 			kd->procbase = (struct kinfo_proc *)
310 			    _kvm_realloc(kd, kd->procbase, size);
311 			if (kd->procbase == 0)
312 				return (0);
313 			st = sysctl(mib, op == KERN_PROC_ALL ? 3 : 4,
314 			    kd->procbase, &size, NULL, 0);
315 		} while (st == -1 && errno == ENOMEM);
316 		if (st == -1) {
317 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
318 			return (0);
319 		}
320 		if (size % sizeof(struct kinfo_proc) != 0) {
321 			_kvm_err(kd, kd->program,
322 				"proc size mismatch (%d total, %d chunks)",
323 				size, sizeof(struct kinfo_proc));
324 			return (0);
325 		}
326 		nprocs = size / sizeof(struct kinfo_proc);
327 	} else {
328 		struct nlist nl[4], *p;
329 
330 		nl[0].n_name = "_nprocs";
331 		nl[1].n_name = "_allproc";
332 		nl[2].n_name = "_zombproc";
333 		nl[3].n_name = 0;
334 
335 		if (kvm_nlist(kd, nl) != 0) {
336 			for (p = nl; p->n_type != 0; ++p)
337 				;
338 			_kvm_err(kd, kd->program,
339 				 "%s: no such symbol", p->n_name);
340 			return (0);
341 		}
342 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
343 			_kvm_err(kd, kd->program, "can't read nprocs");
344 			return (0);
345 		}
346 		size = nprocs * sizeof(struct kinfo_proc);
347 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
348 		if (kd->procbase == 0)
349 			return (0);
350 
351 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
352 				      nl[2].n_value, nprocs);
353 #ifdef notdef
354 		size = nprocs * sizeof(struct kinfo_proc);
355 		(void)realloc(kd->procbase, size);
356 #endif
357 	}
358 	*cnt = nprocs;
359 	return (kd->procbase);
360 }
361 
362 void
363 _kvm_freeprocs(kd)
364 	kvm_t *kd;
365 {
366 	if (kd->procbase) {
367 		free(kd->procbase);
368 		kd->procbase = 0;
369 	}
370 }
371 
372 void *
373 _kvm_realloc(kd, p, n)
374 	kvm_t *kd;
375 	void *p;
376 	size_t n;
377 {
378 	void *np = (void *)realloc(p, n);
379 
380 	if (np == 0) {
381 		free(p);
382 		_kvm_err(kd, kd->program, "out of memory");
383 	}
384 	return (np);
385 }
386 
387 #ifndef MAX
388 #define MAX(a, b) ((a) > (b) ? (a) : (b))
389 #endif
390 
391 /*
392  * Read in an argument vector from the user address space of process p.
393  * addr if the user-space base address of narg null-terminated contiguous
394  * strings.  This is used to read in both the command arguments and
395  * environment strings.  Read at most maxcnt characters of strings.
396  */
397 static char **
398 kvm_argv(kd, p, addr, narg, maxcnt)
399 	kvm_t *kd;
400 	const struct proc *p;
401 	register u_long addr;
402 	register int narg;
403 	register int maxcnt;
404 {
405 	register char *np, *cp, *ep, *ap;
406 	register u_long oaddr = -1;
407 	register int len, cc;
408 	register char **argv;
409 
410 	/*
411 	 * Check that there aren't an unreasonable number of agruments,
412 	 * and that the address is in user space.
413 	 */
414 	if (narg > 512 || addr < VM_MIN_ADDRESS || addr >= VM_MAXUSER_ADDRESS)
415 		return (0);
416 
417 	/*
418 	 * kd->argv : work space for fetching the strings from the target
419 	 *            process's space, and is converted for returning to caller
420 	 */
421 	if (kd->argv == 0) {
422 		/*
423 		 * Try to avoid reallocs.
424 		 */
425 		kd->argc = MAX(narg + 1, 32);
426 		kd->argv = (char **)_kvm_malloc(kd, kd->argc *
427 						sizeof(*kd->argv));
428 		if (kd->argv == 0)
429 			return (0);
430 	} else if (narg + 1 > kd->argc) {
431 		kd->argc = MAX(2 * kd->argc, narg + 1);
432 		kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
433 						sizeof(*kd->argv));
434 		if (kd->argv == 0)
435 			return (0);
436 	}
437 	/*
438 	 * kd->argspc : returned to user, this is where the kd->argv
439 	 *              arrays are left pointing to the collected strings.
440 	 */
441 	if (kd->argspc == 0) {
442 		kd->argspc = (char *)_kvm_malloc(kd, PAGE_SIZE);
443 		if (kd->argspc == 0)
444 			return (0);
445 		kd->arglen = PAGE_SIZE;
446 	}
447 	/*
448 	 * kd->argbuf : used to pull in pages from the target process.
449 	 *              the strings are copied out of here.
450 	 */
451 	if (kd->argbuf == 0) {
452 		kd->argbuf = (char *)_kvm_malloc(kd, PAGE_SIZE);
453 		if (kd->argbuf == 0)
454 			return (0);
455 	}
456 
457 	/* Pull in the target process'es argv vector */
458 	cc = sizeof(char *) * narg;
459 	if (kvm_uread(kd, p, addr, (char *)kd->argv, cc) != cc)
460 		return (0);
461 	/*
462 	 * ap : saved start address of string we're working on in kd->argspc
463 	 * np : pointer to next place to write in kd->argspc
464 	 * len: length of data in kd->argspc
465 	 * argv: pointer to the argv vector that we are hunting around the
466 	 *       target process space for, and converting to addresses in
467 	 *       our address space (kd->argspc).
468 	 */
469 	ap = np = kd->argspc;
470 	argv = kd->argv;
471 	len = 0;
472 	/*
473 	 * Loop over pages, filling in the argument vector.
474 	 * Note that the argv strings could be pointing *anywhere* in
475 	 * the user address space and are no longer contiguous.
476 	 * Note that *argv is modified when we are going to fetch a string
477 	 * that crosses a page boundary.  We copy the next part of the string
478 	 * into to "np" and eventually convert the pointer.
479 	 */
480 	while (argv < kd->argv + narg && *argv != 0) {
481 
482 		/* get the address that the current argv string is on */
483 		addr = (u_long)*argv & ~(PAGE_SIZE - 1);
484 
485 		/* is it the same page as the last one? */
486 		if (addr != oaddr) {
487 			if (kvm_uread(kd, p, addr, kd->argbuf, PAGE_SIZE) !=
488 			    PAGE_SIZE)
489 				return (0);
490 			oaddr = addr;
491 		}
492 
493 		/* offset within the page... kd->argbuf */
494 		addr = (u_long)*argv & (PAGE_SIZE - 1);
495 
496 		/* cp = start of string, cc = count of chars in this chunk */
497 		cp = kd->argbuf + addr;
498 		cc = PAGE_SIZE - addr;
499 
500 		/* dont get more than asked for by user process */
501 		if (maxcnt > 0 && cc > maxcnt - len)
502 			cc = maxcnt - len;
503 
504 		/* pointer to end of string if we found it in this page */
505 		ep = memchr(cp, '\0', cc);
506 		if (ep != 0)
507 			cc = ep - cp + 1;
508 		/*
509 		 * at this point, cc is the count of the chars that we are
510 		 * going to retrieve this time. we may or may not have found
511 		 * the end of it.  (ep points to the null if the end is known)
512 		 */
513 
514 		/* will we exceed the malloc/realloced buffer? */
515 		if (len + cc > kd->arglen) {
516 			register int off;
517 			register char **pp;
518 			register char *op = kd->argspc;
519 
520 			kd->arglen *= 2;
521 			kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
522 							  kd->arglen);
523 			if (kd->argspc == 0)
524 				return (0);
525 			/*
526 			 * Adjust argv pointers in case realloc moved
527 			 * the string space.
528 			 */
529 			off = kd->argspc - op;
530 			for (pp = kd->argv; pp < argv; pp++)
531 				*pp += off;
532 			ap += off;
533 			np += off;
534 		}
535 		/* np = where to put the next part of the string in kd->argspc*/
536 		/* np is kinda redundant.. could use "kd->argspc + len" */
537 		memcpy(np, cp, cc);
538 		np += cc;	/* inc counters */
539 		len += cc;
540 
541 		/*
542 		 * if end of string found, set the *argv pointer to the
543 		 * saved beginning of string, and advance. argv points to
544 		 * somewhere in kd->argv..  This is initially relative
545 		 * to the target process, but when we close it off, we set
546 		 * it to point in our address space.
547 		 */
548 		if (ep != 0) {
549 			*argv++ = ap;
550 			ap = np;
551 		} else {
552 			/* update the address relative to the target process */
553 			*argv += cc;
554 		}
555 
556 		if (maxcnt > 0 && len >= maxcnt) {
557 			/*
558 			 * We're stopping prematurely.  Terminate the
559 			 * current string.
560 			 */
561 			if (ep == 0) {
562 				*np = '\0';
563 				*argv++ = ap;
564 			}
565 			break;
566 		}
567 	}
568 	/* Make sure argv is terminated. */
569 	*argv = 0;
570 	return (kd->argv);
571 }
572 
573 static void
574 ps_str_a(p, addr, n)
575 	struct ps_strings *p;
576 	u_long *addr;
577 	int *n;
578 {
579 	*addr = (u_long)p->ps_argvstr;
580 	*n = p->ps_nargvstr;
581 }
582 
583 static void
584 ps_str_e(p, addr, n)
585 	struct ps_strings *p;
586 	u_long *addr;
587 	int *n;
588 {
589 	*addr = (u_long)p->ps_envstr;
590 	*n = p->ps_nenvstr;
591 }
592 
593 /*
594  * Determine if the proc indicated by p is still active.
595  * This test is not 100% foolproof in theory, but chances of
596  * being wrong are very low.
597  */
598 static int
599 proc_verify(kd, kernp, p)
600 	kvm_t *kd;
601 	u_long kernp;
602 	const struct proc *p;
603 {
604 	struct kinfo_proc kp;
605 	int mib[4];
606 	size_t len;
607 
608 	mib[0] = CTL_KERN;
609 	mib[1] = KERN_PROC;
610 	mib[2] = KERN_PROC_PID;
611 	mib[3] = p->p_pid;
612 	len = sizeof(kp);
613 	if (sysctl(mib, 4, &kp, &len, NULL, 0) == -1)
614 		return (0);
615 	return (p->p_pid == kp.kp_proc.p_pid &&
616 	    (kp.kp_proc.p_stat != SZOMB || p->p_stat == SZOMB));
617 }
618 
619 static char **
620 kvm_doargv(kd, kp, nchr, info)
621 	kvm_t *kd;
622 	const struct kinfo_proc *kp;
623 	int nchr;
624 	void (*info)(struct ps_strings *, u_long *, int *);
625 {
626 	register const struct proc *p = &kp->kp_proc;
627 	register char **ap;
628 	u_long addr;
629 	int cnt;
630 	static struct ps_strings arginfo;
631 	static u_long ps_strings;
632 	size_t len;
633 
634 	if (ps_strings == NULL) {
635 		len = sizeof(ps_strings);
636 		if (sysctlbyname("kern.ps_strings", &ps_strings, &len, NULL,
637 		    0) == -1)
638 			ps_strings = PS_STRINGS;
639 	}
640 
641 	/*
642 	 * Pointers are stored at the top of the user stack.
643 	 */
644 	if (p->p_stat == SZOMB ||
645 	    kvm_uread(kd, p, ps_strings, (char *)&arginfo,
646 		      sizeof(arginfo)) != sizeof(arginfo))
647 		return (0);
648 
649 	(*info)(&arginfo, &addr, &cnt);
650 	if (cnt == 0)
651 		return (0);
652 	ap = kvm_argv(kd, p, addr, cnt, nchr);
653 	/*
654 	 * For live kernels, make sure this process didn't go away.
655 	 */
656 	if (ap != 0 && ISALIVE(kd) &&
657 	    !proc_verify(kd, (u_long)kp->kp_eproc.e_paddr, p))
658 		ap = 0;
659 	return (ap);
660 }
661 
662 /*
663  * Get the command args.  This code is now machine independent.
664  */
665 char **
666 kvm_getargv(kd, kp, nchr)
667 	kvm_t *kd;
668 	const struct kinfo_proc *kp;
669 	int nchr;
670 {
671 	int oid[4];
672 	int i, l;
673 	static int buflen;
674 	static char *buf, *p;
675 	static char **bufp;
676 	static int argc;
677 
678 	if (!buflen) {
679 		l = sizeof(buflen);
680 		i = sysctlbyname("kern.ps_arg_cache_limit",
681 		    &buflen, &l, NULL, 0);
682 		if (i == -1) {
683 			buflen == 0;
684 		} else {
685 			buf = malloc(buflen);
686 			if (buf == NULL)
687 				buflen = 0;
688 			argc = 32;
689 			bufp = malloc(sizeof(char *) * argc);
690 		}
691 	}
692 	if (buf != NULL) {
693 		oid[0] = CTL_KERN;
694 		oid[1] = KERN_PROC;
695 		oid[2] = KERN_PROC_ARGS;
696 		oid[3] = kp->kp_proc.p_pid;
697 		l = buflen;
698 		i = sysctl(oid, 4, buf, &l, 0, 0);
699 		if (i == 0 && l > 0) {
700 			i = 0;
701 			p = buf;
702 			do {
703 				bufp[i++] = p;
704 				p += strlen(p) + 1;
705 				if (i >= argc) {
706 					argc += argc;
707 					bufp = realloc(bufp,
708 					    sizeof(char *) * argc);
709 				}
710 			} while (p < buf + l);
711 			bufp[i++] = 0;
712 			return (bufp);
713 		}
714 	}
715 	if (kp->kp_proc.p_flag & P_SYSTEM)
716 		return (NULL);
717 	return (kvm_doargv(kd, kp, nchr, ps_str_a));
718 }
719 
720 char **
721 kvm_getenvv(kd, kp, nchr)
722 	kvm_t *kd;
723 	const struct kinfo_proc *kp;
724 	int nchr;
725 {
726 	return (kvm_doargv(kd, kp, nchr, ps_str_e));
727 }
728 
729 /*
730  * Read from user space.  The user context is given by p.
731  */
732 ssize_t
733 kvm_uread(kd, p, uva, buf, len)
734 	kvm_t *kd;
735 	register const struct proc *p;
736 	register u_long uva;
737 	register char *buf;
738 	register size_t len;
739 {
740 	register char *cp;
741 	char procfile[MAXPATHLEN];
742 	ssize_t amount;
743 	int fd;
744 
745 	if (!ISALIVE(kd)) {
746 		_kvm_err(kd, kd->program,
747 		    "cannot read user space from dead kernel");
748 		return (0);
749 	}
750 
751 	sprintf(procfile, "/proc/%d/mem", p->p_pid);
752 	fd = open(procfile, O_RDONLY, 0);
753 	if (fd < 0) {
754 		_kvm_err(kd, kd->program, "cannot open %s", procfile);
755 		close(fd);
756 		return (0);
757 	}
758 
759 	cp = buf;
760 	while (len > 0) {
761 		errno = 0;
762 		if (lseek(fd, (off_t)uva, 0) == -1 && errno != 0) {
763 			_kvm_err(kd, kd->program, "invalid address (%x) in %s",
764 			    uva, procfile);
765 			break;
766 		}
767 		amount = read(fd, cp, len);
768 		if (amount < 0) {
769 			_kvm_syserr(kd, kd->program, "error reading %s",
770 			    procfile);
771 			break;
772 		}
773 		if (amount == 0) {
774 			_kvm_err(kd, kd->program, "EOF reading %s", procfile);
775 			break;
776 		}
777 		cp += amount;
778 		uva += amount;
779 		len -= amount;
780 	}
781 
782 	close(fd);
783 	return ((ssize_t)(cp - buf));
784 }
785