xref: /freebsd/lib/libkvm/kvm_proc.c (revision acd3428b7d3e94cef0e1881c868cb4b131d4ff41)
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 
38 #if 0
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 #endif
43 
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46 
47 /*
48  * Proc traversal interface for kvm.  ps and w are (probably) the exclusive
49  * users of this code, so we've factored it out into a separate module.
50  * Thus, we keep this grunge out of the other kvm applications (i.e.,
51  * most other applications are interested only in open/close/read/nlist).
52  */
53 
54 #include <sys/param.h>
55 #define	_WANT_UCRED	/* make ucred.h give us 'struct ucred' */
56 #include <sys/ucred.h>
57 #include <sys/queue.h>
58 #include <sys/_lock.h>
59 #include <sys/_mutex.h>
60 #include <sys/_task.h>
61 #define	_WANT_PRISON	/* make jail.h give us 'struct prison' */
62 #include <sys/jail.h>
63 #include <sys/user.h>
64 #include <sys/proc.h>
65 #include <sys/exec.h>
66 #include <sys/stat.h>
67 #include <sys/sysent.h>
68 #include <sys/ioctl.h>
69 #include <sys/tty.h>
70 #include <sys/file.h>
71 #include <sys/conf.h>
72 #include <stdio.h>
73 #include <stdlib.h>
74 #include <unistd.h>
75 #include <nlist.h>
76 #include <kvm.h>
77 
78 #include <vm/vm.h>
79 #include <vm/vm_param.h>
80 
81 #include <sys/sysctl.h>
82 
83 #include <limits.h>
84 #include <memory.h>
85 #include <paths.h>
86 
87 #include "kvm_private.h"
88 
89 #define KREAD(kd, addr, obj) \
90 	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
91 
92 /*
93  * Read proc's from memory file into buffer bp, which has space to hold
94  * at most maxcnt procs.
95  */
96 static int
97 kvm_proclist(kd, what, arg, p, bp, maxcnt)
98 	kvm_t *kd;
99 	int what, arg;
100 	struct proc *p;
101 	struct kinfo_proc *bp;
102 	int maxcnt;
103 {
104 	int cnt = 0;
105 	struct kinfo_proc kinfo_proc, *kp;
106 	struct pgrp pgrp;
107 	struct session sess;
108 	struct cdev t_cdev;
109 	struct tty tty;
110 	struct vmspace vmspace;
111 	struct sigacts sigacts;
112 	struct pstats pstats;
113 	struct ucred ucred;
114 	struct prison pr;
115 	struct thread mtd;
116 	/*struct kse mke;*/
117 	/*struct ksegrp mkg;*/
118 	struct proc proc;
119 	struct proc pproc;
120 	struct timeval tv;
121 	struct sysentvec sysent;
122 	char svname[KI_EMULNAMELEN];
123 
124 	kp = &kinfo_proc;
125 	kp->ki_structsize = sizeof(kinfo_proc);
126 	for (; cnt < maxcnt && p != NULL; p = LIST_NEXT(&proc, p_list)) {
127 		memset(kp, 0, sizeof *kp);
128 		if (KREAD(kd, (u_long)p, &proc)) {
129 			_kvm_err(kd, kd->program, "can't read proc at %x", p);
130 			return (-1);
131 		}
132 		if (proc.p_state != PRS_ZOMBIE) {
133 			if (KREAD(kd, (u_long)TAILQ_FIRST(&proc.p_threads),
134 			    &mtd)) {
135 				_kvm_err(kd, kd->program,
136 				    "can't read thread at %x",
137 				    TAILQ_FIRST(&proc.p_threads));
138 				return (-1);
139 			}
140 #if 0
141 			if ((proc.p_flag & P_SA) == 0) {
142 				if (KREAD(kd,
143 				    (u_long)TAILQ_FIRST(&proc.p_ksegrps),
144 				    &mkg)) {
145 					_kvm_err(kd, kd->program,
146 					    "can't read ksegrp at %x",
147 					    TAILQ_FIRST(&proc.p_ksegrps));
148 					return (-1);
149 				}
150 				if (KREAD(kd,
151 				    (u_long)TAILQ_FIRST(&mkg.kg_kseq), &mke)) {
152 					_kvm_err(kd, kd->program,
153 					    "can't read kse at %x",
154 					    TAILQ_FIRST(&mkg.kg_kseq));
155 					return (-1);
156 				}
157 			}
158 #endif
159 		}
160 		if (KREAD(kd, (u_long)proc.p_ucred, &ucred) == 0) {
161 			kp->ki_ruid = ucred.cr_ruid;
162 			kp->ki_svuid = ucred.cr_svuid;
163 			kp->ki_rgid = ucred.cr_rgid;
164 			kp->ki_svgid = ucred.cr_svgid;
165 			kp->ki_ngroups = ucred.cr_ngroups;
166 			bcopy(ucred.cr_groups, kp->ki_groups,
167 			    NGROUPS * sizeof(gid_t));
168 			kp->ki_uid = ucred.cr_uid;
169 			if (ucred.cr_prison != NULL) {
170 				if (KREAD(kd, (u_long)ucred.cr_prison, &pr)) {
171 					_kvm_err(kd, kd->program,
172 					    "can't read prison at %x",
173 					    ucred.cr_prison);
174 					return (-1);
175 				}
176 				kp->ki_jid = pr.pr_id;
177 			}
178 		}
179 
180 		switch(what & ~KERN_PROC_INC_THREAD) {
181 
182 		case KERN_PROC_GID:
183 			if (kp->ki_groups[0] != (gid_t)arg)
184 				continue;
185 			break;
186 
187 		case KERN_PROC_PID:
188 			if (proc.p_pid != (pid_t)arg)
189 				continue;
190 			break;
191 
192 		case KERN_PROC_RGID:
193 			if (kp->ki_rgid != (gid_t)arg)
194 				continue;
195 			break;
196 
197 		case KERN_PROC_UID:
198 			if (kp->ki_uid != (uid_t)arg)
199 				continue;
200 			break;
201 
202 		case KERN_PROC_RUID:
203 			if (kp->ki_ruid != (uid_t)arg)
204 				continue;
205 			break;
206 		}
207 		/*
208 		 * We're going to add another proc to the set.  If this
209 		 * will overflow the buffer, assume the reason is because
210 		 * nprocs (or the proc list) is corrupt and declare an error.
211 		 */
212 		if (cnt >= maxcnt) {
213 			_kvm_err(kd, kd->program, "nprocs corrupt");
214 			return (-1);
215 		}
216 		/*
217 		 * gather kinfo_proc
218 		 */
219 		kp->ki_paddr = p;
220 		kp->ki_addr = 0;	/* XXX uarea */
221 		/* kp->ki_kstack = proc.p_thread.td_kstack; XXXKSE */
222 		kp->ki_args = proc.p_args;
223 		kp->ki_tracep = proc.p_tracevp;
224 		kp->ki_textvp = proc.p_textvp;
225 		kp->ki_fd = proc.p_fd;
226 		kp->ki_vmspace = proc.p_vmspace;
227 		if (proc.p_sigacts != NULL) {
228 			if (KREAD(kd, (u_long)proc.p_sigacts, &sigacts)) {
229 				_kvm_err(kd, kd->program,
230 				    "can't read sigacts at %x", proc.p_sigacts);
231 				return (-1);
232 			}
233 			kp->ki_sigignore = sigacts.ps_sigignore;
234 			kp->ki_sigcatch = sigacts.ps_sigcatch;
235 		}
236 		if ((proc.p_sflag & PS_INMEM) && proc.p_stats != NULL) {
237 			if (KREAD(kd, (u_long)proc.p_stats, &pstats)) {
238 				_kvm_err(kd, kd->program,
239 				    "can't read stats at %x", proc.p_stats);
240 				return (-1);
241 			}
242 			kp->ki_start = pstats.p_start;
243 
244 			/*
245 			 * XXX: The times here are probably zero and need
246 			 * to be calculated from the raw data in p_rux and
247 			 * p_crux.
248 			 */
249 			kp->ki_rusage = pstats.p_ru;
250 			kp->ki_childstime = pstats.p_cru.ru_stime;
251 			kp->ki_childutime = pstats.p_cru.ru_utime;
252 			/* Some callers want child-times in a single value */
253 			timeradd(&kp->ki_childstime, &kp->ki_childutime,
254 			    &kp->ki_childtime);
255 		}
256 		if (proc.p_oppid)
257 			kp->ki_ppid = proc.p_oppid;
258 		else if (proc.p_pptr) {
259 			if (KREAD(kd, (u_long)proc.p_pptr, &pproc)) {
260 				_kvm_err(kd, kd->program,
261 				    "can't read pproc at %x", proc.p_pptr);
262 				return (-1);
263 			}
264 			kp->ki_ppid = pproc.p_pid;
265 		} else
266 			kp->ki_ppid = 0;
267 		if (proc.p_pgrp == NULL)
268 			goto nopgrp;
269 		if (KREAD(kd, (u_long)proc.p_pgrp, &pgrp)) {
270 			_kvm_err(kd, kd->program, "can't read pgrp at %x",
271 				 proc.p_pgrp);
272 			return (-1);
273 		}
274 		kp->ki_pgid = pgrp.pg_id;
275 		kp->ki_jobc = pgrp.pg_jobc;
276 		if (KREAD(kd, (u_long)pgrp.pg_session, &sess)) {
277 			_kvm_err(kd, kd->program, "can't read session at %x",
278 				pgrp.pg_session);
279 			return (-1);
280 		}
281 		kp->ki_sid = sess.s_sid;
282 		(void)memcpy(kp->ki_login, sess.s_login,
283 						sizeof(kp->ki_login));
284 		kp->ki_kiflag = sess.s_ttyvp ? KI_CTTY : 0;
285 		if (sess.s_leader == p)
286 			kp->ki_kiflag |= KI_SLEADER;
287 		if ((proc.p_flag & P_CONTROLT) && sess.s_ttyp != NULL) {
288 			if (KREAD(kd, (u_long)sess.s_ttyp, &tty)) {
289 				_kvm_err(kd, kd->program,
290 					 "can't read tty at %x", sess.s_ttyp);
291 				return (-1);
292 			}
293 			if (tty.t_dev != NULL) {
294 				if (KREAD(kd, (u_long)tty.t_dev, &t_cdev)) {
295 					_kvm_err(kd, kd->program,
296 						 "can't read cdev at %x",
297 						tty.t_dev);
298 					return (-1);
299 				}
300 #if 0
301 				kp->ki_tdev = t_cdev.si_udev;
302 #else
303 				kp->ki_tdev = NODEV;
304 #endif
305 			}
306 			if (tty.t_pgrp != NULL) {
307 				if (KREAD(kd, (u_long)tty.t_pgrp, &pgrp)) {
308 					_kvm_err(kd, kd->program,
309 						 "can't read tpgrp at %x",
310 						tty.t_pgrp);
311 					return (-1);
312 				}
313 				kp->ki_tpgid = pgrp.pg_id;
314 			} else
315 				kp->ki_tpgid = -1;
316 			if (tty.t_session != NULL) {
317 				if (KREAD(kd, (u_long)tty.t_session, &sess)) {
318 					_kvm_err(kd, kd->program,
319 					    "can't read session at %x",
320 					    tty.t_session);
321 					return (-1);
322 				}
323 				kp->ki_tsid = sess.s_sid;
324 			}
325 		} else {
326 nopgrp:
327 			kp->ki_tdev = NODEV;
328 		}
329 		if ((proc.p_state != PRS_ZOMBIE) && mtd.td_wmesg)
330 			(void)kvm_read(kd, (u_long)mtd.td_wmesg,
331 			    kp->ki_wmesg, WMESGLEN);
332 
333 		(void)kvm_read(kd, (u_long)proc.p_vmspace,
334 		    (char *)&vmspace, sizeof(vmspace));
335 		kp->ki_size = vmspace.vm_map.size;
336 		kp->ki_rssize = vmspace.vm_swrss; /* XXX */
337 		kp->ki_swrss = vmspace.vm_swrss;
338 		kp->ki_tsize = vmspace.vm_tsize;
339 		kp->ki_dsize = vmspace.vm_dsize;
340 		kp->ki_ssize = vmspace.vm_ssize;
341 
342 		switch (what & ~KERN_PROC_INC_THREAD) {
343 
344 		case KERN_PROC_PGRP:
345 			if (kp->ki_pgid != (pid_t)arg)
346 				continue;
347 			break;
348 
349 		case KERN_PROC_SESSION:
350 			if (kp->ki_sid != (pid_t)arg)
351 				continue;
352 			break;
353 
354 		case KERN_PROC_TTY:
355 			if ((proc.p_flag & P_CONTROLT) == 0 ||
356 			     kp->ki_tdev != (dev_t)arg)
357 				continue;
358 			break;
359 		}
360 		if (proc.p_comm[0] != 0)
361 			strlcpy(kp->ki_comm, proc.p_comm, MAXCOMLEN);
362 		(void)kvm_read(kd, (u_long)proc.p_sysent, (char *)&sysent,
363 		    sizeof(sysent));
364 		(void)kvm_read(kd, (u_long)sysent.sv_name, (char *)&svname,
365 		    sizeof(svname));
366 		if (svname[0] != 0)
367 			strlcpy(kp->ki_emul, svname, KI_EMULNAMELEN);
368 		if ((proc.p_state != PRS_ZOMBIE) &&
369 		    (mtd.td_blocked != 0)) {
370 			kp->ki_kiflag |= KI_LOCKBLOCK;
371 			if (mtd.td_lockname)
372 				(void)kvm_read(kd,
373 				    (u_long)mtd.td_lockname,
374 				    kp->ki_lockname, LOCKNAMELEN);
375 			kp->ki_lockname[LOCKNAMELEN] = 0;
376 		}
377 		/*
378 		 * XXX: This is plain wrong, rux_runtime has nothing
379 		 * to do with struct bintime, rux_runtime is just a 64-bit
380 		 * integer counter of cputicks.  What we need here is a way
381 		 * to convert cputicks to usecs.  The kernel does it in
382 		 * kern/kern_tc.c, but the function can't be just copied.
383 		 */
384 		bintime2timeval(&proc.p_rux.rux_runtime, &tv);
385 		kp->ki_runtime = (u_int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
386 		kp->ki_pid = proc.p_pid;
387 		kp->ki_siglist = proc.p_siglist;
388 		SIGSETOR(kp->ki_siglist, mtd.td_siglist);
389 		kp->ki_sigmask = mtd.td_sigmask;
390 		kp->ki_xstat = proc.p_xstat;
391 		kp->ki_acflag = proc.p_acflag;
392 		kp->ki_lock = proc.p_lock;
393 		if (proc.p_state != PRS_ZOMBIE) {
394 			kp->ki_swtime = proc.p_swtime;
395 			kp->ki_flag = proc.p_flag;
396 			kp->ki_sflag = proc.p_sflag;
397 			kp->ki_nice = proc.p_nice;
398 			kp->ki_traceflag = proc.p_traceflag;
399 			if (proc.p_state == PRS_NORMAL) {
400 				if (TD_ON_RUNQ(&mtd) ||
401 				    TD_CAN_RUN(&mtd) ||
402 				    TD_IS_RUNNING(&mtd)) {
403 					kp->ki_stat = SRUN;
404 				} else if (mtd.td_state ==
405 				    TDS_INHIBITED) {
406 					if (P_SHOULDSTOP(&proc)) {
407 						kp->ki_stat = SSTOP;
408 					} else if (
409 					    TD_IS_SLEEPING(&mtd)) {
410 						kp->ki_stat = SSLEEP;
411 					} else if (TD_ON_LOCK(&mtd)) {
412 						kp->ki_stat = SLOCK;
413 					} else {
414 						kp->ki_stat = SWAIT;
415 					}
416 				}
417 			} else {
418 				kp->ki_stat = SIDL;
419 			}
420 			/* Stuff from the thread */
421 			kp->ki_pri.pri_level = mtd.td_priority;
422 			kp->ki_pri.pri_native = mtd.td_base_pri;
423 			kp->ki_lastcpu = mtd.td_lastcpu;
424 			kp->ki_wchan = mtd.td_wchan;
425 			kp->ki_oncpu = mtd.td_oncpu;
426 
427 			if (!(proc.p_flag & P_SA)) {
428 #if 0
429 				/* stuff from the ksegrp */
430 				kp->ki_slptime = mkg.kg_slptime;
431 				kp->ki_pri.pri_class = mkg.kg_pri_class;
432 				kp->ki_pri.pri_user = mkg.kg_user_pri;
433 				kp->ki_estcpu = mkg.kg_estcpu;
434 
435 				/* Stuff from the kse */
436 				kp->ki_pctcpu = mke.ke_pctcpu;
437 				kp->ki_rqindex = mke.ke_rqindex;
438 #else
439 				kp->ki_pctcpu = 0;
440 				kp->ki_rqindex = 0;
441 #endif
442 			} else {
443 				kp->ki_tdflags = -1;
444 				/* All the rest are 0 for now */
445 			}
446 		} else {
447 			kp->ki_stat = SZOMB;
448 		}
449 		bcopy(&kinfo_proc, bp, sizeof(kinfo_proc));
450 		++bp;
451 		++cnt;
452 	}
453 	return (cnt);
454 }
455 
456 /*
457  * Build proc info array by reading in proc list from a crash dump.
458  * Return number of procs read.  maxcnt is the max we will read.
459  */
460 static int
461 kvm_deadprocs(kd, what, arg, a_allproc, a_zombproc, maxcnt)
462 	kvm_t *kd;
463 	int what, arg;
464 	u_long a_allproc;
465 	u_long a_zombproc;
466 	int maxcnt;
467 {
468 	struct kinfo_proc *bp = kd->procbase;
469 	int acnt, zcnt;
470 	struct proc *p;
471 
472 	if (KREAD(kd, a_allproc, &p)) {
473 		_kvm_err(kd, kd->program, "cannot read allproc");
474 		return (-1);
475 	}
476 	acnt = kvm_proclist(kd, what, arg, p, bp, maxcnt);
477 	if (acnt < 0)
478 		return (acnt);
479 
480 	if (KREAD(kd, a_zombproc, &p)) {
481 		_kvm_err(kd, kd->program, "cannot read zombproc");
482 		return (-1);
483 	}
484 	zcnt = kvm_proclist(kd, what, arg, p, bp + acnt, maxcnt - acnt);
485 	if (zcnt < 0)
486 		zcnt = 0;
487 
488 	return (acnt + zcnt);
489 }
490 
491 struct kinfo_proc *
492 kvm_getprocs(kd, op, arg, cnt)
493 	kvm_t *kd;
494 	int op, arg;
495 	int *cnt;
496 {
497 	int mib[4], st, nprocs;
498 	size_t size;
499 	int temp_op;
500 
501 	if (kd->procbase != 0) {
502 		free((void *)kd->procbase);
503 		/*
504 		 * Clear this pointer in case this call fails.  Otherwise,
505 		 * kvm_close() will free it again.
506 		 */
507 		kd->procbase = 0;
508 	}
509 	if (ISALIVE(kd)) {
510 		size = 0;
511 		mib[0] = CTL_KERN;
512 		mib[1] = KERN_PROC;
513 		mib[2] = op;
514 		mib[3] = arg;
515 		temp_op = op & ~KERN_PROC_INC_THREAD;
516 		st = sysctl(mib,
517 		    temp_op == KERN_PROC_ALL || temp_op == KERN_PROC_PROC ?
518 		    3 : 4, NULL, &size, NULL, 0);
519 		if (st == -1) {
520 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
521 			return (0);
522 		}
523 		/*
524 		 * We can't continue with a size of 0 because we pass
525 		 * it to realloc() (via _kvm_realloc()), and passing 0
526 		 * to realloc() results in undefined behavior.
527 		 */
528 		if (size == 0) {
529 			/*
530 			 * XXX: We should probably return an invalid,
531 			 * but non-NULL, pointer here so any client
532 			 * program trying to dereference it will
533 			 * crash.  However, _kvm_freeprocs() calls
534 			 * free() on kd->procbase if it isn't NULL,
535 			 * and free()'ing a junk pointer isn't good.
536 			 * Then again, _kvm_freeprocs() isn't used
537 			 * anywhere . . .
538 			 */
539 			kd->procbase = _kvm_malloc(kd, 1);
540 			goto liveout;
541 		}
542 		do {
543 			size += size / 10;
544 			kd->procbase = (struct kinfo_proc *)
545 			    _kvm_realloc(kd, kd->procbase, size);
546 			if (kd->procbase == 0)
547 				return (0);
548 			st = sysctl(mib, temp_op == KERN_PROC_ALL ||
549 			    temp_op == KERN_PROC_PROC ? 3 : 4,
550 			    kd->procbase, &size, NULL, 0);
551 		} while (st == -1 && errno == ENOMEM);
552 		if (st == -1) {
553 			_kvm_syserr(kd, kd->program, "kvm_getprocs");
554 			return (0);
555 		}
556 		/*
557 		 * We have to check the size again because sysctl()
558 		 * may "round up" oldlenp if oldp is NULL; hence it
559 		 * might've told us that there was data to get when
560 		 * there really isn't any.
561 		 */
562 		if (size > 0 &&
563 		    kd->procbase->ki_structsize != sizeof(struct kinfo_proc)) {
564 			_kvm_err(kd, kd->program,
565 			    "kinfo_proc size mismatch (expected %d, got %d)",
566 			    sizeof(struct kinfo_proc),
567 			    kd->procbase->ki_structsize);
568 			return (0);
569 		}
570 liveout:
571 		nprocs = size == 0 ? 0 : size / kd->procbase->ki_structsize;
572 	} else {
573 		struct nlist nl[4], *p;
574 
575 		nl[0].n_name = "_nprocs";
576 		nl[1].n_name = "_allproc";
577 		nl[2].n_name = "_zombproc";
578 		nl[3].n_name = 0;
579 
580 		if (kvm_nlist(kd, nl) != 0) {
581 			for (p = nl; p->n_type != 0; ++p)
582 				;
583 			_kvm_err(kd, kd->program,
584 				 "%s: no such symbol", p->n_name);
585 			return (0);
586 		}
587 		if (KREAD(kd, nl[0].n_value, &nprocs)) {
588 			_kvm_err(kd, kd->program, "can't read nprocs");
589 			return (0);
590 		}
591 		size = nprocs * sizeof(struct kinfo_proc);
592 		kd->procbase = (struct kinfo_proc *)_kvm_malloc(kd, size);
593 		if (kd->procbase == 0)
594 			return (0);
595 
596 		nprocs = kvm_deadprocs(kd, op, arg, nl[1].n_value,
597 				      nl[2].n_value, nprocs);
598 #ifdef notdef
599 		size = nprocs * sizeof(struct kinfo_proc);
600 		(void)realloc(kd->procbase, size);
601 #endif
602 	}
603 	*cnt = nprocs;
604 	return (kd->procbase);
605 }
606 
607 void
608 _kvm_freeprocs(kd)
609 	kvm_t *kd;
610 {
611 	if (kd->procbase) {
612 		free(kd->procbase);
613 		kd->procbase = 0;
614 	}
615 }
616 
617 void *
618 _kvm_realloc(kd, p, n)
619 	kvm_t *kd;
620 	void *p;
621 	size_t n;
622 {
623 	void *np = (void *)realloc(p, n);
624 
625 	if (np == 0) {
626 		free(p);
627 		_kvm_err(kd, kd->program, "out of memory");
628 	}
629 	return (np);
630 }
631 
632 #ifndef MAX
633 #define MAX(a, b) ((a) > (b) ? (a) : (b))
634 #endif
635 
636 /*
637  * Read in an argument vector from the user address space of process kp.
638  * addr if the user-space base address of narg null-terminated contiguous
639  * strings.  This is used to read in both the command arguments and
640  * environment strings.  Read at most maxcnt characters of strings.
641  */
642 static char **
643 kvm_argv(kd, kp, addr, narg, maxcnt)
644 	kvm_t *kd;
645 	struct kinfo_proc *kp;
646 	u_long addr;
647 	int narg;
648 	int maxcnt;
649 {
650 	char *np, *cp, *ep, *ap;
651 	u_long oaddr = -1;
652 	int len, cc;
653 	char **argv;
654 
655 	/*
656 	 * Check that there aren't an unreasonable number of agruments,
657 	 * and that the address is in user space.
658 	 */
659 	if (narg > 512 || addr < VM_MIN_ADDRESS || addr >= VM_MAXUSER_ADDRESS)
660 		return (0);
661 
662 	/*
663 	 * kd->argv : work space for fetching the strings from the target
664 	 *            process's space, and is converted for returning to caller
665 	 */
666 	if (kd->argv == 0) {
667 		/*
668 		 * Try to avoid reallocs.
669 		 */
670 		kd->argc = MAX(narg + 1, 32);
671 		kd->argv = (char **)_kvm_malloc(kd, kd->argc *
672 						sizeof(*kd->argv));
673 		if (kd->argv == 0)
674 			return (0);
675 	} else if (narg + 1 > kd->argc) {
676 		kd->argc = MAX(2 * kd->argc, narg + 1);
677 		kd->argv = (char **)_kvm_realloc(kd, kd->argv, kd->argc *
678 						sizeof(*kd->argv));
679 		if (kd->argv == 0)
680 			return (0);
681 	}
682 	/*
683 	 * kd->argspc : returned to user, this is where the kd->argv
684 	 *              arrays are left pointing to the collected strings.
685 	 */
686 	if (kd->argspc == 0) {
687 		kd->argspc = (char *)_kvm_malloc(kd, PAGE_SIZE);
688 		if (kd->argspc == 0)
689 			return (0);
690 		kd->arglen = PAGE_SIZE;
691 	}
692 	/*
693 	 * kd->argbuf : used to pull in pages from the target process.
694 	 *              the strings are copied out of here.
695 	 */
696 	if (kd->argbuf == 0) {
697 		kd->argbuf = (char *)_kvm_malloc(kd, PAGE_SIZE);
698 		if (kd->argbuf == 0)
699 			return (0);
700 	}
701 
702 	/* Pull in the target process'es argv vector */
703 	cc = sizeof(char *) * narg;
704 	if (kvm_uread(kd, kp, addr, (char *)kd->argv, cc) != cc)
705 		return (0);
706 	/*
707 	 * ap : saved start address of string we're working on in kd->argspc
708 	 * np : pointer to next place to write in kd->argspc
709 	 * len: length of data in kd->argspc
710 	 * argv: pointer to the argv vector that we are hunting around the
711 	 *       target process space for, and converting to addresses in
712 	 *       our address space (kd->argspc).
713 	 */
714 	ap = np = kd->argspc;
715 	argv = kd->argv;
716 	len = 0;
717 	/*
718 	 * Loop over pages, filling in the argument vector.
719 	 * Note that the argv strings could be pointing *anywhere* in
720 	 * the user address space and are no longer contiguous.
721 	 * Note that *argv is modified when we are going to fetch a string
722 	 * that crosses a page boundary.  We copy the next part of the string
723 	 * into to "np" and eventually convert the pointer.
724 	 */
725 	while (argv < kd->argv + narg && *argv != 0) {
726 
727 		/* get the address that the current argv string is on */
728 		addr = (u_long)*argv & ~(PAGE_SIZE - 1);
729 
730 		/* is it the same page as the last one? */
731 		if (addr != oaddr) {
732 			if (kvm_uread(kd, kp, addr, kd->argbuf, PAGE_SIZE) !=
733 			    PAGE_SIZE)
734 				return (0);
735 			oaddr = addr;
736 		}
737 
738 		/* offset within the page... kd->argbuf */
739 		addr = (u_long)*argv & (PAGE_SIZE - 1);
740 
741 		/* cp = start of string, cc = count of chars in this chunk */
742 		cp = kd->argbuf + addr;
743 		cc = PAGE_SIZE - addr;
744 
745 		/* dont get more than asked for by user process */
746 		if (maxcnt > 0 && cc > maxcnt - len)
747 			cc = maxcnt - len;
748 
749 		/* pointer to end of string if we found it in this page */
750 		ep = memchr(cp, '\0', cc);
751 		if (ep != 0)
752 			cc = ep - cp + 1;
753 		/*
754 		 * at this point, cc is the count of the chars that we are
755 		 * going to retrieve this time. we may or may not have found
756 		 * the end of it.  (ep points to the null if the end is known)
757 		 */
758 
759 		/* will we exceed the malloc/realloced buffer? */
760 		if (len + cc > kd->arglen) {
761 			int off;
762 			char **pp;
763 			char *op = kd->argspc;
764 
765 			kd->arglen *= 2;
766 			kd->argspc = (char *)_kvm_realloc(kd, kd->argspc,
767 							  kd->arglen);
768 			if (kd->argspc == 0)
769 				return (0);
770 			/*
771 			 * Adjust argv pointers in case realloc moved
772 			 * the string space.
773 			 */
774 			off = kd->argspc - op;
775 			for (pp = kd->argv; pp < argv; pp++)
776 				*pp += off;
777 			ap += off;
778 			np += off;
779 		}
780 		/* np = where to put the next part of the string in kd->argspc*/
781 		/* np is kinda redundant.. could use "kd->argspc + len" */
782 		memcpy(np, cp, cc);
783 		np += cc;	/* inc counters */
784 		len += cc;
785 
786 		/*
787 		 * if end of string found, set the *argv pointer to the
788 		 * saved beginning of string, and advance. argv points to
789 		 * somewhere in kd->argv..  This is initially relative
790 		 * to the target process, but when we close it off, we set
791 		 * it to point in our address space.
792 		 */
793 		if (ep != 0) {
794 			*argv++ = ap;
795 			ap = np;
796 		} else {
797 			/* update the address relative to the target process */
798 			*argv += cc;
799 		}
800 
801 		if (maxcnt > 0 && len >= maxcnt) {
802 			/*
803 			 * We're stopping prematurely.  Terminate the
804 			 * current string.
805 			 */
806 			if (ep == 0) {
807 				*np = '\0';
808 				*argv++ = ap;
809 			}
810 			break;
811 		}
812 	}
813 	/* Make sure argv is terminated. */
814 	*argv = 0;
815 	return (kd->argv);
816 }
817 
818 static void
819 ps_str_a(p, addr, n)
820 	struct ps_strings *p;
821 	u_long *addr;
822 	int *n;
823 {
824 	*addr = (u_long)p->ps_argvstr;
825 	*n = p->ps_nargvstr;
826 }
827 
828 static void
829 ps_str_e(p, addr, n)
830 	struct ps_strings *p;
831 	u_long *addr;
832 	int *n;
833 {
834 	*addr = (u_long)p->ps_envstr;
835 	*n = p->ps_nenvstr;
836 }
837 
838 /*
839  * Determine if the proc indicated by p is still active.
840  * This test is not 100% foolproof in theory, but chances of
841  * being wrong are very low.
842  */
843 static int
844 proc_verify(curkp)
845 	struct kinfo_proc *curkp;
846 {
847 	struct kinfo_proc newkp;
848 	int mib[4];
849 	size_t len;
850 
851 	mib[0] = CTL_KERN;
852 	mib[1] = KERN_PROC;
853 	mib[2] = KERN_PROC_PID;
854 	mib[3] = curkp->ki_pid;
855 	len = sizeof(newkp);
856 	if (sysctl(mib, 4, &newkp, &len, NULL, 0) == -1)
857 		return (0);
858 	return (curkp->ki_pid == newkp.ki_pid &&
859 	    (newkp.ki_stat != SZOMB || curkp->ki_stat == SZOMB));
860 }
861 
862 static char **
863 kvm_doargv(kd, kp, nchr, info)
864 	kvm_t *kd;
865 	struct kinfo_proc *kp;
866 	int nchr;
867 	void (*info)(struct ps_strings *, u_long *, int *);
868 {
869 	char **ap;
870 	u_long addr;
871 	int cnt;
872 	static struct ps_strings arginfo;
873 	static u_long ps_strings;
874 	size_t len;
875 
876 	if (ps_strings == 0) {
877 		len = sizeof(ps_strings);
878 		if (sysctlbyname("kern.ps_strings", &ps_strings, &len, NULL,
879 		    0) == -1)
880 			ps_strings = PS_STRINGS;
881 	}
882 
883 	/*
884 	 * Pointers are stored at the top of the user stack.
885 	 */
886 	if (kp->ki_stat == SZOMB ||
887 	    kvm_uread(kd, kp, ps_strings, (char *)&arginfo,
888 		      sizeof(arginfo)) != sizeof(arginfo))
889 		return (0);
890 
891 	(*info)(&arginfo, &addr, &cnt);
892 	if (cnt == 0)
893 		return (0);
894 	ap = kvm_argv(kd, kp, addr, cnt, nchr);
895 	/*
896 	 * For live kernels, make sure this process didn't go away.
897 	 */
898 	if (ap != 0 && ISALIVE(kd) && !proc_verify(kp))
899 		ap = 0;
900 	return (ap);
901 }
902 
903 /*
904  * Get the command args.  This code is now machine independent.
905  */
906 char **
907 kvm_getargv(kd, kp, nchr)
908 	kvm_t *kd;
909 	const struct kinfo_proc *kp;
910 	int nchr;
911 {
912 	int oid[4];
913 	int i;
914 	size_t bufsz;
915 	static unsigned long buflen;
916 	static char *buf, *p;
917 	static char **bufp;
918 	static int argc;
919 
920 	if (!ISALIVE(kd)) {
921 		_kvm_err(kd, kd->program,
922 		    "cannot read user space from dead kernel");
923 		return (0);
924 	}
925 
926 	if (!buflen) {
927 		bufsz = sizeof(buflen);
928 		i = sysctlbyname("kern.ps_arg_cache_limit",
929 		    &buflen, &bufsz, NULL, 0);
930 		if (i == -1) {
931 			buflen = 0;
932 		} else {
933 			buf = malloc(buflen);
934 			if (buf == NULL)
935 				buflen = 0;
936 			argc = 32;
937 			bufp = malloc(sizeof(char *) * argc);
938 		}
939 	}
940 	if (buf != NULL) {
941 		oid[0] = CTL_KERN;
942 		oid[1] = KERN_PROC;
943 		oid[2] = KERN_PROC_ARGS;
944 		oid[3] = kp->ki_pid;
945 		bufsz = buflen;
946 		i = sysctl(oid, 4, buf, &bufsz, 0, 0);
947 		if (i == 0 && bufsz > 0) {
948 			i = 0;
949 			p = buf;
950 			do {
951 				bufp[i++] = p;
952 				p += strlen(p) + 1;
953 				if (i >= argc) {
954 					argc += argc;
955 					bufp = realloc(bufp,
956 					    sizeof(char *) * argc);
957 				}
958 			} while (p < buf + bufsz);
959 			bufp[i++] = 0;
960 			return (bufp);
961 		}
962 	}
963 	if (kp->ki_flag & P_SYSTEM)
964 		return (NULL);
965 	return (kvm_doargv(kd, kp, nchr, ps_str_a));
966 }
967 
968 char **
969 kvm_getenvv(kd, kp, nchr)
970 	kvm_t *kd;
971 	const struct kinfo_proc *kp;
972 	int nchr;
973 {
974 	return (kvm_doargv(kd, kp, nchr, ps_str_e));
975 }
976 
977 /*
978  * Read from user space.  The user context is given by p.
979  */
980 ssize_t
981 kvm_uread(kd, kp, uva, buf, len)
982 	kvm_t *kd;
983 	struct kinfo_proc *kp;
984 	u_long uva;
985 	char *buf;
986 	size_t len;
987 {
988 	char *cp;
989 	char procfile[MAXPATHLEN];
990 	ssize_t amount;
991 	int fd;
992 
993 	if (!ISALIVE(kd)) {
994 		_kvm_err(kd, kd->program,
995 		    "cannot read user space from dead kernel");
996 		return (0);
997 	}
998 
999 	sprintf(procfile, "/proc/%d/mem", kp->ki_pid);
1000 	fd = open(procfile, O_RDONLY, 0);
1001 	if (fd < 0) {
1002 		_kvm_err(kd, kd->program, "cannot open %s", procfile);
1003 		return (0);
1004 	}
1005 
1006 	cp = buf;
1007 	while (len > 0) {
1008 		errno = 0;
1009 		if (lseek(fd, (off_t)uva, 0) == -1 && errno != 0) {
1010 			_kvm_err(kd, kd->program, "invalid address (%x) in %s",
1011 			    uva, procfile);
1012 			break;
1013 		}
1014 		amount = read(fd, cp, len);
1015 		if (amount < 0) {
1016 			_kvm_syserr(kd, kd->program, "error reading %s",
1017 			    procfile);
1018 			break;
1019 		}
1020 		if (amount == 0) {
1021 			_kvm_err(kd, kd->program, "EOF reading %s", procfile);
1022 			break;
1023 		}
1024 		cp += amount;
1025 		uva += amount;
1026 		len -= amount;
1027 	}
1028 
1029 	close(fd);
1030 	return ((ssize_t)(cp - buf));
1031 }
1032