xref: /freebsd/sbin/sysctl/sysctl.c (revision 9fd69f37d28cfd7438cac3eeb45fe9dd46b4d7dd)
1 /*
2  * Copyright (c) 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #ifndef lint
31 static const char copyright[] =
32 "@(#) Copyright (c) 1993\n\
33 	The Regents of the University of California.  All rights reserved.\n";
34 #endif /* not lint */
35 
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)from: sysctl.c	8.1 (Berkeley) 6/6/93";
39 #endif
40 static const char rcsid[] =
41   "$FreeBSD$";
42 #endif /* not lint */
43 
44 #include <sys/param.h>
45 #include <sys/time.h>
46 #include <sys/resource.h>
47 #include <sys/stat.h>
48 #include <sys/sysctl.h>
49 #include <sys/vmmeter.h>
50 
51 #include <ctype.h>
52 #include <err.h>
53 #include <errno.h>
54 #include <inttypes.h>
55 #include <locale.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60 
61 static int	aflag, bflag, dflag, eflag, hflag, iflag;
62 static int	Nflag, nflag, oflag, qflag, xflag, warncount;
63 
64 static int	oidfmt(int *, int, char *, u_int *);
65 static void	parse(char *);
66 static int	show_var(int *, int);
67 static int	sysctl_all(int *oid, int len);
68 static int	name2oid(char *, int *);
69 
70 static void	set_T_dev_t(char *, void **, size_t *);
71 static int	set_IK(const char *, int *);
72 
73 static void
74 usage(void)
75 {
76 
77 	(void)fprintf(stderr, "%s\n%s\n",
78 	    "usage: sysctl [-bdehiNnoqx] name[=value] ...",
79 	    "       sysctl [-bdehNnoqx] -a");
80 	exit(1);
81 }
82 
83 int
84 main(int argc, char **argv)
85 {
86 	int ch;
87 
88 	setlocale(LC_NUMERIC, "");
89 	setbuf(stdout,0);
90 	setbuf(stderr,0);
91 
92 	while ((ch = getopt(argc, argv, "AabdehiNnoqwxX")) != -1) {
93 		switch (ch) {
94 		case 'A':
95 			/* compatibility */
96 			aflag = oflag = 1;
97 			break;
98 		case 'a':
99 			aflag = 1;
100 			break;
101 		case 'b':
102 			bflag = 1;
103 			break;
104 		case 'd':
105 			dflag = 1;
106 			break;
107 		case 'e':
108 			eflag = 1;
109 			break;
110 		case 'h':
111 			hflag = 1;
112 			break;
113 		case 'i':
114 			iflag = 1;
115 			break;
116 		case 'N':
117 			Nflag = 1;
118 			break;
119 		case 'n':
120 			nflag = 1;
121 			break;
122 		case 'o':
123 			oflag = 1;
124 			break;
125 		case 'q':
126 			qflag = 1;
127 			break;
128 		case 'w':
129 			/* compatibility */
130 			/* ignored */
131 			break;
132 		case 'X':
133 			/* compatibility */
134 			aflag = xflag = 1;
135 			break;
136 		case 'x':
137 			xflag = 1;
138 			break;
139 		default:
140 			usage();
141 		}
142 	}
143 	argc -= optind;
144 	argv += optind;
145 
146 	if (Nflag && nflag)
147 		usage();
148 	if (aflag && argc == 0)
149 		exit(sysctl_all(0, 0));
150 	if (argc == 0)
151 		usage();
152 
153 	warncount = 0;
154 	while (argc-- > 0)
155 		parse(*argv++);
156 	exit(warncount);
157 }
158 
159 /*
160  * Parse a name into a MIB entry.
161  * Lookup and print out the MIB entry if it exists.
162  * Set a new value if requested.
163  */
164 static void
165 parse(char *string)
166 {
167 	int len, i, j;
168 	void *newval = 0;
169 	int intval;
170 	unsigned int uintval;
171 	long longval;
172 	unsigned long ulongval;
173 	size_t newsize = 0;
174 	quad_t quadval;
175 	int mib[CTL_MAXNAME];
176 	char *cp, *bufp, buf[BUFSIZ], *endptr, fmt[BUFSIZ];
177 	u_int kind;
178 
179 	bufp = buf;
180 	if (snprintf(buf, BUFSIZ, "%s", string) >= BUFSIZ)
181 		errx(1, "oid too long: '%s'", string);
182 	if ((cp = strchr(string, '=')) != NULL) {
183 		*strchr(buf, '=') = '\0';
184 		*cp++ = '\0';
185 		while (isspace(*cp))
186 			cp++;
187 		newval = cp;
188 		newsize = strlen(cp);
189 	}
190 	len = name2oid(bufp, mib);
191 
192 	if (len < 0) {
193 		if (iflag)
194 			return;
195 		if (qflag)
196 			exit(1);
197 		else
198 			errx(1, "unknown oid '%s'", bufp);
199 	}
200 
201 	if (oidfmt(mib, len, fmt, &kind))
202 		err(1, "couldn't find format of oid '%s'", bufp);
203 
204 	if (newval == NULL) {
205 		if ((kind & CTLTYPE) == CTLTYPE_NODE) {
206 			if (dflag) {
207 				i = show_var(mib, len);
208 				if (!i && !bflag)
209 					putchar('\n');
210 			}
211 			sysctl_all(mib, len);
212 		} else {
213 			i = show_var(mib, len);
214 			if (!i && !bflag)
215 				putchar('\n');
216 		}
217 	} else {
218 		if ((kind & CTLTYPE) == CTLTYPE_NODE)
219 			errx(1, "oid '%s' isn't a leaf node", bufp);
220 
221 		if (!(kind & CTLFLAG_WR)) {
222 			if (kind & CTLFLAG_TUN) {
223 				warnx("oid '%s' is a read only tunable", bufp);
224 				errx(1, "Tunable values are set in /boot/loader.conf");
225 			} else {
226 				errx(1, "oid '%s' is read only", bufp);
227 			}
228 		}
229 
230 		if ((kind & CTLTYPE) == CTLTYPE_INT ||
231 		    (kind & CTLTYPE) == CTLTYPE_UINT ||
232 		    (kind & CTLTYPE) == CTLTYPE_LONG ||
233 		    (kind & CTLTYPE) == CTLTYPE_ULONG ||
234 		    (kind & CTLTYPE) == CTLTYPE_QUAD) {
235 			if (strlen(newval) == 0)
236 				errx(1, "empty numeric value");
237 		}
238 
239 		switch (kind & CTLTYPE) {
240 			case CTLTYPE_INT:
241 				if (strcmp(fmt, "IK") == 0) {
242 					if (!set_IK(newval, &intval))
243 						errx(1, "invalid value '%s'",
244 						    (char *)newval);
245  				} else {
246 					intval = (int)strtol(newval, &endptr,
247 					    0);
248 					if (endptr == newval || *endptr != '\0')
249 						errx(1, "invalid integer '%s'",
250 						    (char *)newval);
251 				}
252 				newval = &intval;
253 				newsize = sizeof(intval);
254 				break;
255 			case CTLTYPE_UINT:
256 				uintval = (int) strtoul(newval, &endptr, 0);
257 				if (endptr == newval || *endptr != '\0')
258 					errx(1, "invalid unsigned integer '%s'",
259 					    (char *)newval);
260 				newval = &uintval;
261 				newsize = sizeof(uintval);
262 				break;
263 			case CTLTYPE_LONG:
264 				longval = strtol(newval, &endptr, 0);
265 				if (endptr == newval || *endptr != '\0')
266 					errx(1, "invalid long integer '%s'",
267 					    (char *)newval);
268 				newval = &longval;
269 				newsize = sizeof(longval);
270 				break;
271 			case CTLTYPE_ULONG:
272 				ulongval = strtoul(newval, &endptr, 0);
273 				if (endptr == newval || *endptr != '\0')
274 					errx(1, "invalid unsigned long integer"
275 					    " '%s'", (char *)newval);
276 				newval = &ulongval;
277 				newsize = sizeof(ulongval);
278 				break;
279 			case CTLTYPE_STRING:
280 				break;
281 			case CTLTYPE_QUAD:
282 				quadval = strtoq(newval, &endptr, 0);
283 				if (endptr == newval || *endptr != '\0')
284 					errx(1, "invalid quad integer"
285 					    " '%s'", (char *)newval);
286 				newval = &quadval;
287 				newsize = sizeof(quadval);
288 				break;
289 			case CTLTYPE_OPAQUE:
290 				if (strcmp(fmt, "T,dev_t") == 0) {
291 					set_T_dev_t (newval, &newval, &newsize);
292 					break;
293 				}
294 				/* FALLTHROUGH */
295 			default:
296 				errx(1, "oid '%s' is type %d,"
297 					" cannot set that", bufp,
298 					kind & CTLTYPE);
299 		}
300 
301 		i = show_var(mib, len);
302 		if (sysctl(mib, len, 0, 0, newval, newsize) == -1) {
303 			if (!i && !bflag)
304 				putchar('\n');
305 			switch (errno) {
306 			case EOPNOTSUPP:
307 				errx(1, "%s: value is not available",
308 					string);
309 			case ENOTDIR:
310 				errx(1, "%s: specification is incomplete",
311 					string);
312 			case ENOMEM:
313 				errx(1, "%s: type is unknown to this program",
314 					string);
315 			default:
316 				warn("%s", string);
317 				warncount++;
318 				return;
319 			}
320 		}
321 		if (!bflag)
322 			printf(" -> ");
323 		i = nflag;
324 		nflag = 1;
325 		j = show_var(mib, len);
326 		if (!j && !bflag)
327 			putchar('\n');
328 		nflag = i;
329 	}
330 }
331 
332 /* These functions will dump out various interesting structures. */
333 
334 static int
335 S_clockinfo(int l2, void *p)
336 {
337 	struct clockinfo *ci = (struct clockinfo*)p;
338 
339 	if (l2 != sizeof(*ci)) {
340 		warnx("S_clockinfo %d != %zu", l2, sizeof(*ci));
341 		return (1);
342 	}
343 	printf(hflag ? "{ hz = %'d, tick = %'d, profhz = %'d, stathz = %'d }" :
344 		"{ hz = %d, tick = %d, profhz = %d, stathz = %d }",
345 		ci->hz, ci->tick, ci->profhz, ci->stathz);
346 	return (0);
347 }
348 
349 static int
350 S_loadavg(int l2, void *p)
351 {
352 	struct loadavg *tv = (struct loadavg*)p;
353 
354 	if (l2 != sizeof(*tv)) {
355 		warnx("S_loadavg %d != %zu", l2, sizeof(*tv));
356 		return (1);
357 	}
358 	printf(hflag ? "{ %'.2f %'.2f %'.2f }" : "{ %.2f %.2f %.2f }",
359 		(double)tv->ldavg[0]/(double)tv->fscale,
360 		(double)tv->ldavg[1]/(double)tv->fscale,
361 		(double)tv->ldavg[2]/(double)tv->fscale);
362 	return (0);
363 }
364 
365 static int
366 S_timeval(int l2, void *p)
367 {
368 	struct timeval *tv = (struct timeval*)p;
369 	time_t tv_sec;
370 	char *p1, *p2;
371 
372 	if (l2 != sizeof(*tv)) {
373 		warnx("S_timeval %d != %zu", l2, sizeof(*tv));
374 		return (1);
375 	}
376 	printf(hflag ? "{ sec = %'jd, usec = %'ld } " :
377 		"{ sec = %jd, usec = %ld } ",
378 		(intmax_t)tv->tv_sec, tv->tv_usec);
379 	tv_sec = tv->tv_sec;
380 	p1 = strdup(ctime(&tv_sec));
381 	for (p2=p1; *p2 ; p2++)
382 		if (*p2 == '\n')
383 			*p2 = '\0';
384 	fputs(p1, stdout);
385 	return (0);
386 }
387 
388 static int
389 S_vmtotal(int l2, void *p)
390 {
391 	struct vmtotal *v = (struct vmtotal *)p;
392 	int pageKilo = getpagesize() / 1024;
393 
394 	if (l2 != sizeof(*v)) {
395 		warnx("S_vmtotal %d != %zu", l2, sizeof(*v));
396 		return (1);
397 	}
398 
399 	printf(
400 	    "\nSystem wide totals computed every five seconds:"
401 	    " (values in kilobytes)\n");
402 	printf("===============================================\n");
403 	printf(
404 	    "Processes:\t\t(RUNQ: %hd Disk Wait: %hd Page Wait: "
405 	    "%hd Sleep: %hd)\n",
406 	    v->t_rq, v->t_dw, v->t_pw, v->t_sl);
407 	printf(
408 	    "Virtual Memory:\t\t(Total: %dK, Active %dK)\n",
409 	    v->t_vm * pageKilo, v->t_avm * pageKilo);
410 	printf("Real Memory:\t\t(Total: %dK Active %dK)\n",
411 	    v->t_rm * pageKilo, v->t_arm * pageKilo);
412 	printf("Shared Virtual Memory:\t(Total: %dK Active: %dK)\n",
413 	    v->t_vmshr * pageKilo, v->t_avmshr * pageKilo);
414 	printf("Shared Real Memory:\t(Total: %dK Active: %dK)\n",
415 	    v->t_rmshr * pageKilo, v->t_armshr * pageKilo);
416 	printf("Free Memory Pages:\t%dK\n", v->t_free * pageKilo);
417 
418 	return (0);
419 }
420 
421 static int
422 T_dev_t(int l2, void *p)
423 {
424 	dev_t *d = (dev_t *)p;
425 
426 	if (l2 != sizeof(*d)) {
427 		warnx("T_dev_T %d != %zu", l2, sizeof(*d));
428 		return (1);
429 	}
430 	printf("%s", devname(*d, S_IFCHR));
431 	return (0);
432 }
433 
434 static void
435 set_T_dev_t(char *path, void **val, size_t *size)
436 {
437 	static struct stat statb;
438 
439 	if (strcmp(path, "none") && strcmp(path, "off")) {
440 		int rc = stat (path, &statb);
441 		if (rc) {
442 			err(1, "cannot stat %s", path);
443 		}
444 
445 		if (!S_ISCHR(statb.st_mode)) {
446 			errx(1, "must specify a device special file.");
447 		}
448 	} else {
449 		statb.st_rdev = NODEV;
450 	}
451 	*val = (void *) &statb.st_rdev;
452 	*size = sizeof(statb.st_rdev);
453 }
454 
455 static int
456 set_IK(const char *str, int *val)
457 {
458 	float temp;
459 	int len, kelv;
460 	const char *p;
461 	char *endptr;
462 
463 	if ((len = strlen(str)) == 0)
464 		return (0);
465 	p = &str[len - 1];
466 	if (*p == 'C' || *p == 'F') {
467 		temp = strtof(str, &endptr);
468 		if (endptr == str || endptr != p)
469 			return (0);
470 		if (*p == 'F')
471 			temp = (temp - 32) * 5 / 9;
472 		kelv = temp * 10 + 2732;
473 	} else {
474 		kelv = (int)strtol(str, &endptr, 10);
475 		if (endptr == str || *endptr != '\0')
476 			return (0);
477 	}
478 	*val = kelv;
479 	return (1);
480 }
481 
482 /*
483  * These functions uses a presently undocumented interface to the kernel
484  * to walk the tree and get the type so it can print the value.
485  * This interface is under work and consideration, and should probably
486  * be killed with a big axe by the first person who can find the time.
487  * (be aware though, that the proper interface isn't as obvious as it
488  * may seem, there are various conflicting requirements.
489  */
490 
491 static int
492 name2oid(char *name, int *oidp)
493 {
494 	int oid[2];
495 	int i;
496 	size_t j;
497 
498 	oid[0] = 0;
499 	oid[1] = 3;
500 
501 	j = CTL_MAXNAME * sizeof(int);
502 	i = sysctl(oid, 2, oidp, &j, name, strlen(name));
503 	if (i < 0)
504 		return (i);
505 	j /= sizeof(int);
506 	return (j);
507 }
508 
509 static int
510 oidfmt(int *oid, int len, char *fmt, u_int *kind)
511 {
512 	int qoid[CTL_MAXNAME+2];
513 	u_char buf[BUFSIZ];
514 	int i;
515 	size_t j;
516 
517 	qoid[0] = 0;
518 	qoid[1] = 4;
519 	memcpy(qoid + 2, oid, len * sizeof(int));
520 
521 	j = sizeof(buf);
522 	i = sysctl(qoid, len + 2, buf, &j, 0, 0);
523 	if (i)
524 		err(1, "sysctl fmt %d %zu %d", i, j, errno);
525 
526 	if (kind)
527 		*kind = *(u_int *)buf;
528 
529 	if (fmt)
530 		strcpy(fmt, (char *)(buf + sizeof(u_int)));
531 	return (0);
532 }
533 
534 /*
535  * This formats and outputs the value of one variable
536  *
537  * Returns zero if anything was actually output.
538  * Returns one if didn't know what to do with this.
539  * Return minus one if we had errors.
540  */
541 
542 static int
543 show_var(int *oid, int nlen)
544 {
545 	u_char buf[BUFSIZ], *val, *oval, *p;
546 	char name[BUFSIZ], *fmt;
547 	const char *sep, *sep1;
548 	int qoid[CTL_MAXNAME+2];
549 	uintmax_t umv;
550 	intmax_t mv;
551 	int i, hexlen;
552 	size_t intlen;
553 	size_t j, len;
554 	u_int kind;
555 	int (*func)(int, void *);
556 
557 	/* Silence GCC. */
558 	umv = mv = intlen = 0;
559 
560 	bzero(buf, BUFSIZ);
561 	bzero(name, BUFSIZ);
562 	qoid[0] = 0;
563 	memcpy(qoid + 2, oid, nlen * sizeof(int));
564 
565 	qoid[1] = 1;
566 	j = sizeof(name);
567 	i = sysctl(qoid, nlen + 2, name, &j, 0, 0);
568 	if (i || !j)
569 		err(1, "sysctl name %d %zu %d", i, j, errno);
570 
571 	if (Nflag) {
572 		printf("%s", name);
573 		return (0);
574 	}
575 
576 	if (eflag)
577 		sep = "=";
578 	else
579 		sep = ": ";
580 
581 	if (dflag) {	/* just print description */
582 		qoid[1] = 5;
583 		j = sizeof(buf);
584 		i = sysctl(qoid, nlen + 2, buf, &j, 0, 0);
585 		if (!nflag)
586 			printf("%s%s", name, sep);
587 		printf("%s", buf);
588 		return (0);
589 	}
590 	/* find an estimate of how much we need for this var */
591 	j = 0;
592 	i = sysctl(oid, nlen, 0, &j, 0, 0);
593 	j += j; /* we want to be sure :-) */
594 
595 	val = oval = malloc(j + 1);
596 	if (val == NULL) {
597 		warnx("malloc failed");
598 		return (1);
599 	}
600 	len = j;
601 	i = sysctl(oid, nlen, val, &len, 0, 0);
602 	if (i || !len) {
603 		free(oval);
604 		return (1);
605 	}
606 
607 	if (bflag) {
608 		fwrite(val, 1, len, stdout);
609 		free(oval);
610 		return (0);
611 	}
612 	val[len] = '\0';
613 	fmt = buf;
614 	oidfmt(oid, nlen, fmt, &kind);
615 	p = val;
616 	switch (*fmt) {
617 	case 'A':
618 		if (!nflag)
619 			printf("%s%s", name, sep);
620 		printf("%.*s", (int)len, p);
621 		free(oval);
622 		return (0);
623 
624 	case 'I':
625 	case 'L':
626 	case 'Q':
627 		if (!nflag)
628 			printf("%s%s", name, sep);
629 		switch (*fmt) {
630 		case 'I': intlen = sizeof(int); break;
631 		case 'L': intlen = sizeof(long); break;
632 		case 'Q': intlen = sizeof(quad_t); break;
633 		}
634 		hexlen = 2 + (intlen * CHAR_BIT + 3) / 4;
635 		sep1 = "";
636 		while (len >= intlen) {
637 			switch (*fmt) {
638 			case 'I':
639 				umv = *(u_int *)p;
640 				mv = *(int *)p;
641 				break;
642 			case 'L':
643 				umv = *(u_long *)p;
644 				mv = *(long *)p;
645 				break;
646 			case 'Q':
647 				umv = *(u_quad_t *)p;
648 				mv = *(quad_t *)p;
649 				break;
650 			}
651 			fputs(sep1, stdout);
652 			if (fmt[1] == 'U')
653 				printf(hflag ? "%'ju" : "%ju", umv);
654 			else if (fmt[1] == 'X')
655 				printf("%#0*jx", hexlen, umv);
656 			else if (fmt[1] == 'K') {
657 				if (mv < 0)
658 					printf("%jd", mv);
659 				else
660 					printf("%.1fC", (mv - 2732.0) / 10);
661 			} else
662 				printf(hflag ? "%'jd" : "%jd", mv);
663 			sep1 = " ";
664 			len -= intlen;
665 			p += intlen;
666 		}
667 		free(oval);
668 		return (0);
669 
670 	case 'P':
671 		if (!nflag)
672 			printf("%s%s", name, sep);
673 		printf("%p", *(void **)p);
674 		free(oval);
675 		return (0);
676 
677 	case 'T':
678 	case 'S':
679 		i = 0;
680 		if (strcmp(fmt, "S,clockinfo") == 0)
681 			func = S_clockinfo;
682 		else if (strcmp(fmt, "S,timeval") == 0)
683 			func = S_timeval;
684 		else if (strcmp(fmt, "S,loadavg") == 0)
685 			func = S_loadavg;
686 		else if (strcmp(fmt, "S,vmtotal") == 0)
687 			func = S_vmtotal;
688 		else if (strcmp(fmt, "T,dev_t") == 0)
689 			func = T_dev_t;
690 		else
691 			func = NULL;
692 		if (func) {
693 			if (!nflag)
694 				printf("%s%s", name, sep);
695 			i = (*func)(len, p);
696 			free(oval);
697 			return (i);
698 		}
699 		/* FALLTHROUGH */
700 	default:
701 		if (!oflag && !xflag) {
702 			free(oval);
703 			return (1);
704 		}
705 		if (!nflag)
706 			printf("%s%s", name, sep);
707 		printf("Format:%s Length:%zu Dump:0x", fmt, len);
708 		while (len-- && (xflag || p < val + 16))
709 			printf("%02x", *p++);
710 		if (!xflag && len > 16)
711 			printf("...");
712 		free(oval);
713 		return (0);
714 	}
715 	free(oval);
716 	return (1);
717 }
718 
719 static int
720 sysctl_all(int *oid, int len)
721 {
722 	int name1[22], name2[22];
723 	int i, j;
724 	size_t l1, l2;
725 
726 	name1[0] = 0;
727 	name1[1] = 2;
728 	l1 = 2;
729 	if (len) {
730 		memcpy(name1+2, oid, len * sizeof(int));
731 		l1 += len;
732 	} else {
733 		name1[2] = 1;
734 		l1++;
735 	}
736 	for (;;) {
737 		l2 = sizeof(name2);
738 		j = sysctl(name1, l1, name2, &l2, 0, 0);
739 		if (j < 0) {
740 			if (errno == ENOENT)
741 				return (0);
742 			else
743 				err(1, "sysctl(getnext) %d %zu", j, l2);
744 		}
745 
746 		l2 /= sizeof(int);
747 
748 		if (len < 0 || l2 < (unsigned int)len)
749 			return (0);
750 
751 		for (i = 0; i < len; i++)
752 			if (name2[i] != oid[i])
753 				return (0);
754 
755 		i = show_var(name2, l2);
756 		if (!i && !bflag)
757 			putchar('\n');
758 
759 		memcpy(name1+2, name2, l2 * sizeof(int));
760 		l1 = 2 + l2;
761 	}
762 }
763