xref: /freebsd/usr.bin/vmstat/vmstat.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*
2  * Copyright (c) 1980, 1986, 1991, 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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 static const char copyright[] =
36 "@(#) Copyright (c) 1980, 1986, 1991, 1993\n\
37 	The Regents of the University of California.  All rights reserved.\n";
38 #endif /* not lint */
39 
40 #if 0
41 #ifndef lint
42 static char sccsid[] = "@(#)vmstat.c	8.1 (Berkeley) 6/6/93";
43 #endif /* not lint */
44 #endif
45 
46 #include <sys/cdefs.h>
47 __FBSDID("$FreeBSD$");
48 
49 #include <sys/param.h>
50 #include <sys/time.h>
51 #include <sys/proc.h>
52 #include <sys/uio.h>
53 #include <sys/namei.h>
54 #include <sys/malloc.h>
55 #include <sys/signal.h>
56 #include <sys/fcntl.h>
57 #include <sys/ioctl.h>
58 #include <sys/resource.h>
59 #include <sys/sysctl.h>
60 #include <sys/vmmeter.h>
61 
62 #include <vm/vm_param.h>
63 
64 #include <ctype.h>
65 #include <devstat.h>
66 #include <err.h>
67 #include <errno.h>
68 #include <kvm.h>
69 #include <limits.h>
70 #include <memstat.h>
71 #include <nlist.h>
72 #include <paths.h>
73 #include <stdio.h>
74 #include <stdlib.h>
75 #include <string.h>
76 #include <sysexits.h>
77 #include <time.h>
78 #include <unistd.h>
79 #include <libutil.h>
80 
81 static char da[] = "da";
82 
83 static struct nlist namelist[] = {
84 #define X_SUM		0
85 	{ "_cnt" },
86 #define	X_BOOTTIME	1
87 	{ "_boottime" },
88 #define X_HZ		2
89 	{ "_hz" },
90 #define X_STATHZ	3
91 	{ "_stathz" },
92 #define X_NCHSTATS	4
93 	{ "_nchstats" },
94 #define	X_INTRNAMES	5
95 	{ "_intrnames" },
96 #define	X_EINTRNAMES	6
97 	{ "_eintrnames" },
98 #define	X_INTRCNT	7
99 	{ "_intrcnt" },
100 #define	X_EINTRCNT	8
101 	{ "_eintrcnt" },
102 #define	X_KMEMSTATS	9
103 	{ "_kmemstatistics" },
104 #define	X_KMEMZONES	10
105 	{ "_kmemzones" },
106 #ifdef notyet
107 #define	X_DEFICIT	XXX
108 	{ "_deficit" },
109 #define X_REC		XXX
110 	{ "_rectime" },
111 #define X_PGIN		XXX
112 	{ "_pgintime" },
113 #define	X_XSTATS	XXX
114 	{ "_xstats" },
115 #define X_END		XXX
116 #else
117 #define X_END		11
118 #endif
119 	{ "" },
120 };
121 
122 static struct statinfo cur, last;
123 static int num_devices, maxshowdevs;
124 static long generation;
125 static struct device_selection *dev_select;
126 static int num_selected;
127 static struct devstat_match *matches;
128 static int num_matches = 0;
129 static int num_devices_specified, num_selections;
130 static long select_generation;
131 static char **specified_devices;
132 static devstat_select_mode select_mode;
133 
134 static struct	vmmeter sum, osum;
135 
136 #define	VMSTAT_DEFAULT_LINES	20	/* Default number of `winlines'. */
137 volatile sig_atomic_t wresized;		/* Tty resized, when non-zero. */
138 static int winlines = VMSTAT_DEFAULT_LINES; /* Current number of tty rows. */
139 
140 static int	aflag;
141 static int	nflag;
142 static int	Pflag;
143 static int	hflag;
144 
145 static kvm_t   *kd;
146 
147 #define	FORKSTAT	0x01
148 #define	INTRSTAT	0x02
149 #define	MEMSTAT		0x04
150 #define	SUMSTAT		0x08
151 #define	TIMESTAT	0x10
152 #define	VMSTAT		0x20
153 #define ZMEMSTAT	0x40
154 
155 static void	cpustats(void);
156 static void	pcpustats(int, u_long, int);
157 static void	devstats(void);
158 static void	doforkst(void);
159 static void	dointr(void);
160 static void	dosum(void);
161 static void	dovmstat(unsigned int, int);
162 static void	domemstat_malloc(void);
163 static void	domemstat_zone(void);
164 static void	kread(int, void *, size_t);
165 static void	kreado(int, void *, size_t, size_t);
166 static char    *kgetstr(const char *);
167 static void	needhdr(int);
168 static void	needresize(int);
169 static void	doresize(void);
170 static void	printhdr(int, u_long);
171 static void	usage(void);
172 
173 static long	pct(long, long);
174 static long	getuptime(void);
175 
176 static char   **getdrivedata(char **);
177 
178 int
179 main(int argc, char *argv[])
180 {
181 	int c, todo;
182 	unsigned int interval;
183 	int reps;
184 	char *memf, *nlistf;
185 	char errbuf[_POSIX2_LINE_MAX];
186 
187 	memf = nlistf = NULL;
188 	interval = reps = todo = 0;
189 	maxshowdevs = 2;
190 	hflag = isatty(1);
191 	while ((c = getopt(argc, argv, "ac:fhHiM:mN:n:Pp:stw:z")) != -1) {
192 		switch (c) {
193 		case 'a':
194 			aflag++;
195 			break;
196 		case 'c':
197 			reps = atoi(optarg);
198 			break;
199 		case 'P':
200 			Pflag++;
201 			break;
202 		case 'f':
203 			todo |= FORKSTAT;
204 			break;
205 		case 'h':
206 			hflag = 1;
207 			break;
208 		case 'H':
209 			hflag = 0;
210 			break;
211 		case 'i':
212 			todo |= INTRSTAT;
213 			break;
214 		case 'M':
215 			memf = optarg;
216 			break;
217 		case 'm':
218 			todo |= MEMSTAT;
219 			break;
220 		case 'N':
221 			nlistf = optarg;
222 			break;
223 		case 'n':
224 			nflag = 1;
225 			maxshowdevs = atoi(optarg);
226 			if (maxshowdevs < 0)
227 				errx(1, "number of devices %d is < 0",
228 				     maxshowdevs);
229 			break;
230 		case 'p':
231 			if (devstat_buildmatch(optarg, &matches, &num_matches) != 0)
232 				errx(1, "%s", devstat_errbuf);
233 			break;
234 		case 's':
235 			todo |= SUMSTAT;
236 			break;
237 		case 't':
238 #ifdef notyet
239 			todo |= TIMESTAT;
240 #else
241 			errx(EX_USAGE, "sorry, -t is not (re)implemented yet");
242 #endif
243 			break;
244 		case 'w':
245 			interval = atoi(optarg);
246 			break;
247 		case 'z':
248 			todo |= ZMEMSTAT;
249 			break;
250 		case '?':
251 		default:
252 			usage();
253 		}
254 	}
255 	argc -= optind;
256 	argv += optind;
257 
258 	if (todo == 0)
259 		todo = VMSTAT;
260 
261 	if (memf != NULL) {
262 		kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
263 		if (kd == NULL)
264 			errx(1, "kvm_openfiles: %s", errbuf);
265 	}
266 
267 	if (kd != NULL && (c = kvm_nlist(kd, namelist)) != 0) {
268 		if (c > 0) {
269 			warnx("undefined symbols:");
270 			for (c = 0;
271 			     c < (int)(sizeof(namelist)/sizeof(namelist[0]));
272 			     c++)
273 				if (namelist[c].n_type == 0)
274 					(void)fprintf(stderr, " %s",
275 					    namelist[c].n_name);
276 			(void)fputc('\n', stderr);
277 		} else
278 			warnx("kvm_nlist: %s", kvm_geterr(kd));
279 		exit(1);
280 	}
281 	if (kd && Pflag)
282 		errx(1, "Cannot use -P with crash dumps");
283 
284 	if (todo & VMSTAT) {
285 		/*
286 		 * Make sure that the userland devstat version matches the
287 		 * kernel devstat version.  If not, exit and print a
288 		 * message informing the user of his mistake.
289 		 */
290 		if (devstat_checkversion(NULL) < 0)
291 			errx(1, "%s", devstat_errbuf);
292 
293 
294 		argv = getdrivedata(argv);
295 	}
296 
297 #define	BACKWARD_COMPATIBILITY
298 #ifdef	BACKWARD_COMPATIBILITY
299 	if (*argv) {
300 		interval = atoi(*argv);
301 		if (*++argv)
302 			reps = atoi(*argv);
303 	}
304 #endif
305 
306 	if (interval) {
307 		if (!reps)
308 			reps = -1;
309 	} else if (reps)
310 		interval = 1;
311 
312 	if (todo & FORKSTAT)
313 		doforkst();
314 	if (todo & MEMSTAT)
315 		domemstat_malloc();
316 	if (todo & ZMEMSTAT)
317 		domemstat_zone();
318 	if (todo & SUMSTAT)
319 		dosum();
320 #ifdef notyet
321 	if (todo & TIMESTAT)
322 		dotimes();
323 #endif
324 	if (todo & INTRSTAT)
325 		dointr();
326 	if (todo & VMSTAT)
327 		dovmstat(interval, reps);
328 	exit(0);
329 }
330 
331 static int
332 mysysctl(const char *name, void *oldp, size_t *oldlenp,
333     void *newp, size_t newlen)
334 {
335 	int error;
336 
337 	error = sysctlbyname(name, oldp, oldlenp, newp, newlen);
338 	if (error != 0 && errno != ENOMEM)
339 		err(1, "sysctl(%s)", name);
340 	return (error);
341 }
342 
343 static char **
344 getdrivedata(char **argv)
345 {
346 	if ((num_devices = devstat_getnumdevs(NULL)) < 0)
347 		errx(1, "%s", devstat_errbuf);
348 
349 	cur.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
350 	last.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
351 
352 	if (devstat_getdevs(NULL, &cur) == -1)
353 		errx(1, "%s", devstat_errbuf);
354 
355 	num_devices = cur.dinfo->numdevs;
356 	generation = cur.dinfo->generation;
357 
358 	specified_devices = (char **)malloc(sizeof(char *));
359 	for (num_devices_specified = 0; *argv; ++argv) {
360 		if (isdigit(**argv))
361 			break;
362 		num_devices_specified++;
363 		specified_devices = (char **)realloc(specified_devices,
364 						     sizeof(char *) *
365 						     num_devices_specified);
366 		specified_devices[num_devices_specified - 1] = *argv;
367 	}
368 	dev_select = NULL;
369 
370 	if (nflag == 0 && maxshowdevs < num_devices_specified)
371 			maxshowdevs = num_devices_specified;
372 
373 	/*
374 	 * People are generally only interested in disk statistics when
375 	 * they're running vmstat.  So, that's what we're going to give
376 	 * them if they don't specify anything by default.  We'll also give
377 	 * them any other random devices in the system so that we get to
378 	 * maxshowdevs devices, if that many devices exist.  If the user
379 	 * specifies devices on the command line, either through a pattern
380 	 * match or by naming them explicitly, we will give the user only
381 	 * those devices.
382 	 */
383 	if ((num_devices_specified == 0) && (num_matches == 0)) {
384 		if (devstat_buildmatch(da, &matches, &num_matches) != 0)
385 			errx(1, "%s", devstat_errbuf);
386 
387 		select_mode = DS_SELECT_ADD;
388 	} else
389 		select_mode = DS_SELECT_ONLY;
390 
391 	/*
392 	 * At this point, selectdevs will almost surely indicate that the
393 	 * device list has changed, so we don't look for return values of 0
394 	 * or 1.  If we get back -1, though, there is an error.
395 	 */
396 	if (devstat_selectdevs(&dev_select, &num_selected, &num_selections,
397 		       &select_generation, generation, cur.dinfo->devices,
398 		       num_devices, matches, num_matches, specified_devices,
399 		       num_devices_specified, select_mode,
400 		       maxshowdevs, 0) == -1)
401 		errx(1, "%s", devstat_errbuf);
402 
403 	return(argv);
404 }
405 
406 static long
407 getuptime(void)
408 {
409 	struct timespec sp;
410 	time_t uptime;
411 
412 	(void)clock_gettime(CLOCK_MONOTONIC, &sp);
413 	uptime = sp.tv_sec;
414 	if (uptime <= 0 || uptime > 60*60*24*365*10)
415 		errx(1, "time makes no sense; namelist must be wrong");
416 
417 	return(uptime);
418 }
419 
420 static void
421 fill_vmmeter(struct vmmeter *vmmp)
422 {
423 	if (kd != NULL) {
424 		kread(X_SUM, vmmp, sizeof(*vmmp));
425 	} else {
426 		size_t size = sizeof(unsigned int);
427 #define GET_VM_STATS(cat, name) \
428 	mysysctl("vm.stats." #cat "." #name, &vmmp->name, &size, NULL, 0)
429 		/* sys */
430 		GET_VM_STATS(sys, v_swtch);
431 		GET_VM_STATS(sys, v_trap);
432 		GET_VM_STATS(sys, v_syscall);
433 		GET_VM_STATS(sys, v_intr);
434 		GET_VM_STATS(sys, v_soft);
435 
436 		/* vm */
437 		GET_VM_STATS(vm, v_vm_faults);
438 		GET_VM_STATS(vm, v_cow_faults);
439 		GET_VM_STATS(vm, v_cow_optim);
440 		GET_VM_STATS(vm, v_zfod);
441 		GET_VM_STATS(vm, v_ozfod);
442 		GET_VM_STATS(vm, v_swapin);
443 		GET_VM_STATS(vm, v_swapout);
444 		GET_VM_STATS(vm, v_swappgsin);
445 		GET_VM_STATS(vm, v_swappgsout);
446 		GET_VM_STATS(vm, v_vnodein);
447 		GET_VM_STATS(vm, v_vnodeout);
448 		GET_VM_STATS(vm, v_vnodepgsin);
449 		GET_VM_STATS(vm, v_vnodepgsout);
450 		GET_VM_STATS(vm, v_intrans);
451 		GET_VM_STATS(vm, v_reactivated);
452 		GET_VM_STATS(vm, v_pdwakeups);
453 		GET_VM_STATS(vm, v_pdpages);
454 		GET_VM_STATS(vm, v_tcached);
455 		GET_VM_STATS(vm, v_dfree);
456 		GET_VM_STATS(vm, v_pfree);
457 		GET_VM_STATS(vm, v_tfree);
458 		GET_VM_STATS(vm, v_page_size);
459 		GET_VM_STATS(vm, v_page_count);
460 		GET_VM_STATS(vm, v_free_reserved);
461 		GET_VM_STATS(vm, v_free_target);
462 		GET_VM_STATS(vm, v_free_min);
463 		GET_VM_STATS(vm, v_free_count);
464 		GET_VM_STATS(vm, v_wire_count);
465 		GET_VM_STATS(vm, v_active_count);
466 		GET_VM_STATS(vm, v_inactive_target);
467 		GET_VM_STATS(vm, v_inactive_count);
468 		GET_VM_STATS(vm, v_cache_count);
469 		GET_VM_STATS(vm, v_cache_min);
470 		GET_VM_STATS(vm, v_cache_max);
471 		GET_VM_STATS(vm, v_pageout_free_min);
472 		GET_VM_STATS(vm, v_interrupt_free_min);
473 		/*GET_VM_STATS(vm, v_free_severe);*/
474 		GET_VM_STATS(vm, v_forks);
475 		GET_VM_STATS(vm, v_vforks);
476 		GET_VM_STATS(vm, v_rforks);
477 		GET_VM_STATS(vm, v_kthreads);
478 		GET_VM_STATS(vm, v_forkpages);
479 		GET_VM_STATS(vm, v_vforkpages);
480 		GET_VM_STATS(vm, v_rforkpages);
481 		GET_VM_STATS(vm, v_kthreadpages);
482 #undef GET_VM_STATS
483 	}
484 }
485 
486 static void
487 fill_vmtotal(struct vmtotal *vmtp)
488 {
489 	if (kd != NULL) {
490 		/* XXX fill vmtp */
491 		errx(1, "not implemented");
492 	} else {
493 		size_t size = sizeof(*vmtp);
494 		mysysctl("vm.vmtotal", vmtp, &size, NULL, 0);
495 		if (size != sizeof(*vmtp))
496 			errx(1, "vm.total size mismatch");
497 	}
498 }
499 
500 /* Determine how many cpu columns, and what index they are in kern.cp_times */
501 static int
502 getcpuinfo(u_long *maskp, int *maxidp)
503 {
504 	int maxcpu;
505 	int maxid;
506 	int ncpus;
507 	int i, j;
508 	int empty;
509 	size_t size;
510 	long *times;
511 	u_long mask;
512 
513 	if (kd != NULL)
514 		errx(1, "not implemented");
515 	mask = 0;
516 	ncpus = 0;
517 	size = sizeof(maxcpu);
518 	mysysctl("kern.smp.maxcpus", &maxcpu, &size, NULL, 0);
519 	if (size != sizeof(maxcpu))
520 		errx(1, "sysctl kern.smp.maxcpus");
521 	size = sizeof(long) * maxcpu * CPUSTATES;
522 	times = malloc(size);
523 	if (times == NULL)
524 		err(1, "malloc %zd bytes", size);
525 	mysysctl("kern.cp_times", times, &size, NULL, 0);
526 	maxid = (size / CPUSTATES / sizeof(long)) - 1;
527 	for (i = 0; i <= maxid; i++) {
528 		empty = 1;
529 		for (j = 0; empty && j < CPUSTATES; j++) {
530 			if (times[i * CPUSTATES + j] != 0)
531 				empty = 0;
532 		}
533 		if (!empty) {
534 			mask |= (1ul << i);
535 			ncpus++;
536 		}
537 	}
538 	if (maskp)
539 		*maskp = mask;
540 	if (maxidp)
541 		*maxidp = maxid;
542 	return (ncpus);
543 }
544 
545 
546 static void
547 prthuman(u_int64_t val, int size)
548 {
549 	char buf[10];
550 	int flags;
551 
552 	if (size < 5 || size > 9)
553 		errx(1, "doofus");
554 	flags = HN_B | HN_NOSPACE | HN_DECIMAL;
555 	humanize_number(buf, size, val, "", HN_AUTOSCALE, flags);
556 	printf("%*s", size, buf);
557 }
558 
559 static int hz, hdrcnt;
560 
561 static long *cur_cp_times;
562 static long *last_cp_times;
563 static size_t size_cp_times;
564 
565 static void
566 dovmstat(unsigned int interval, int reps)
567 {
568 	struct vmtotal total;
569 	time_t uptime, halfuptime;
570 	struct devinfo *tmp_dinfo;
571 	size_t size;
572 	int ncpus, maxid;
573 	u_long cpumask;
574 
575 	uptime = getuptime();
576 	halfuptime = uptime / 2;
577 
578 	/*
579 	 * If the user stops the program (control-Z) and then resumes it,
580 	 * print out the header again.
581 	 */
582 	(void)signal(SIGCONT, needhdr);
583 
584 	/*
585 	 * If our standard output is a tty, then install a SIGWINCH handler
586 	 * and set wresized so that our first iteration through the main
587 	 * vmstat loop will peek at the terminal's current rows to find out
588 	 * how many lines can fit in a screenful of output.
589 	 */
590 	if (isatty(fileno(stdout)) != 0) {
591 		wresized = 1;
592 		(void)signal(SIGWINCH, needresize);
593 	} else {
594 		wresized = 0;
595 		winlines = VMSTAT_DEFAULT_LINES;
596 	}
597 
598 	if (kd != NULL) {
599 		if (namelist[X_STATHZ].n_type != 0 &&
600 		    namelist[X_STATHZ].n_value != 0)
601 			kread(X_STATHZ, &hz, sizeof(hz));
602 		if (!hz)
603 			kread(X_HZ, &hz, sizeof(hz));
604 	} else {
605 		struct clockinfo clockrate;
606 
607 		size = sizeof(clockrate);
608 		mysysctl("kern.clockrate", &clockrate, &size, NULL, 0);
609 		if (size != sizeof(clockrate))
610 			errx(1, "clockrate size mismatch");
611 		hz = clockrate.hz;
612 	}
613 
614 	if (Pflag) {
615 		ncpus = getcpuinfo(&cpumask, &maxid);
616 		size_cp_times = sizeof(long) * (maxid + 1) * CPUSTATES;
617 		cur_cp_times = calloc(1, size_cp_times);
618 		last_cp_times = calloc(1, size_cp_times);
619 	}
620 	for (hdrcnt = 1;;) {
621 		if (!--hdrcnt)
622 			printhdr(ncpus, cpumask);
623 		if (kd != NULL) {
624 			if (kvm_getcptime(kd, cur.cp_time) < 0)
625 				errx(1, "kvm_getcptime: %s", kvm_geterr(kd));
626 		} else {
627 			size = sizeof(cur.cp_time);
628 			mysysctl("kern.cp_time", &cur.cp_time, &size, NULL, 0);
629 			if (size != sizeof(cur.cp_time))
630 				errx(1, "cp_time size mismatch");
631 		}
632 		if (Pflag) {
633 			size = size_cp_times;
634 			mysysctl("kern.cp_times", cur_cp_times, &size, NULL, 0);
635 			if (size != size_cp_times)
636 				errx(1, "cp_times mismatch");
637 		}
638 
639 		tmp_dinfo = last.dinfo;
640 		last.dinfo = cur.dinfo;
641 		cur.dinfo = tmp_dinfo;
642 		last.snap_time = cur.snap_time;
643 
644 		/*
645 		 * Here what we want to do is refresh our device stats.
646 		 * getdevs() returns 1 when the device list has changed.
647 		 * If the device list has changed, we want to go through
648 		 * the selection process again, in case a device that we
649 		 * were previously displaying has gone away.
650 		 */
651 		switch (devstat_getdevs(NULL, &cur)) {
652 		case -1:
653 			errx(1, "%s", devstat_errbuf);
654 			break;
655 		case 1: {
656 			int retval;
657 
658 			num_devices = cur.dinfo->numdevs;
659 			generation = cur.dinfo->generation;
660 
661 			retval = devstat_selectdevs(&dev_select, &num_selected,
662 					    &num_selections, &select_generation,
663 					    generation, cur.dinfo->devices,
664 					    num_devices, matches, num_matches,
665 					    specified_devices,
666 					    num_devices_specified, select_mode,
667 					    maxshowdevs, 0);
668 			switch (retval) {
669 			case -1:
670 				errx(1, "%s", devstat_errbuf);
671 				break;
672 			case 1:
673 				printhdr(ncpus, cpumask);
674 				break;
675 			default:
676 				break;
677 			}
678 		}
679 		default:
680 			break;
681 		}
682 
683 		fill_vmmeter(&sum);
684 		fill_vmtotal(&total);
685 		(void)printf("%2d %1d %1d",
686 		    total.t_rq - 1, total.t_dw + total.t_pw, total.t_sw);
687 #define vmstat_pgtok(a) ((a) * (sum.v_page_size >> 10))
688 #define	rate(x)	(((x) + halfuptime) / uptime)	/* round */
689 		if (hflag) {
690 			printf(" ");
691 			prthuman(total.t_avm * (u_int64_t)sum.v_page_size, 7);
692 			printf(" ");
693 			prthuman(total.t_free * (u_int64_t)sum.v_page_size, 6);
694 			printf(" ");
695 		} else {
696 			printf(" %7d ", vmstat_pgtok(total.t_avm));
697 			printf(" %6d ", vmstat_pgtok(total.t_free));
698 		}
699 		(void)printf("%5lu ",
700 		    (unsigned long)rate(sum.v_vm_faults - osum.v_vm_faults));
701 		(void)printf("%3lu ",
702 		    (unsigned long)rate(sum.v_reactivated - osum.v_reactivated));
703 		(void)printf("%3lu ",
704 		    (unsigned long)rate(sum.v_swapin + sum.v_vnodein -
705 		    (osum.v_swapin + osum.v_vnodein)));
706 		(void)printf("%3lu ",
707 		    (unsigned long)rate(sum.v_swapout + sum.v_vnodeout -
708 		    (osum.v_swapout + osum.v_vnodeout)));
709 		(void)printf("%5lu ",
710 		    (unsigned long)rate(sum.v_tfree - osum.v_tfree));
711 		(void)printf("%3lu ",
712 		    (unsigned long)rate(sum.v_pdpages - osum.v_pdpages));
713 		devstats();
714 		(void)printf("%4lu %4lu %4lu",
715 		    (unsigned long)rate(sum.v_intr - osum.v_intr),
716 		    (unsigned long)rate(sum.v_syscall - osum.v_syscall),
717 		    (unsigned long)rate(sum.v_swtch - osum.v_swtch));
718 		if (Pflag)
719 			pcpustats(ncpus, cpumask, maxid);
720 		else
721 			cpustats();
722 		(void)printf("\n");
723 		(void)fflush(stdout);
724 		if (reps >= 0 && --reps <= 0)
725 			break;
726 		osum = sum;
727 		uptime = interval;
728 		/*
729 		 * We round upward to avoid losing low-frequency events
730 		 * (i.e., >= 1 per interval but < 1 per second).
731 		 */
732 		if (interval != 1)
733 			halfuptime = (uptime + 1) / 2;
734 		else
735 			halfuptime = 0;
736 		(void)sleep(interval);
737 	}
738 }
739 
740 static void
741 printhdr(int ncpus, u_long cpumask)
742 {
743 	int i, num_shown;
744 
745 	num_shown = (num_selected < maxshowdevs) ? num_selected : maxshowdevs;
746 	(void)printf(" procs      memory      page%*s", 19, "");
747 	if (num_shown > 1)
748 		(void)printf(" disks %*s", num_shown * 4 - 7, "");
749 	else if (num_shown == 1)
750 		(void)printf("disk");
751 	(void)printf("   faults         ");
752 	if (Pflag) {
753 		for (i = 0; i < ncpus; i++) {
754 			if (cpumask & (1ul << i))
755 				printf("cpu%-2d    ", i);
756 		}
757 		printf("\n");
758 	} else
759 		printf("cpu\n");
760 	(void)printf(" r b w     avm    fre   flt  re  pi  po    fr  sr ");
761 	for (i = 0; i < num_devices; i++)
762 		if ((dev_select[i].selected)
763 		 && (dev_select[i].selected <= maxshowdevs))
764 			(void)printf("%c%c%d ", dev_select[i].device_name[0],
765 				     dev_select[i].device_name[1],
766 				     dev_select[i].unit_number);
767 	(void)printf("  in   sy   cs");
768 	if (Pflag) {
769 		for (i = 0; i < ncpus; i++)
770 			printf(" us sy id");
771 		printf("\n");
772 	} else
773 		printf(" us sy id\n");
774 	if (wresized != 0)
775 		doresize();
776 	hdrcnt = winlines;
777 }
778 
779 /*
780  * Force a header to be prepended to the next output.
781  */
782 static void
783 needhdr(int dummy __unused)
784 {
785 
786 	hdrcnt = 1;
787 }
788 
789 /*
790  * When the terminal is resized, force an update of the maximum number of rows
791  * printed between each header repetition.  Then force a new header to be
792  * prepended to the next output.
793  */
794 void
795 needresize(int signo)
796 {
797 
798 	wresized = 1;
799 	hdrcnt = 1;
800 }
801 
802 /*
803  * Update the global `winlines' count of terminal rows.
804  */
805 void
806 doresize(void)
807 {
808 	int status;
809 	struct winsize w;
810 
811 	for (;;) {
812 		status = ioctl(fileno(stdout), TIOCGWINSZ, &w);
813 		if (status == -1 && errno == EINTR)
814 			continue;
815 		else if (status == -1)
816 			err(1, "ioctl");
817 		if (w.ws_row > 3)
818 			winlines = w.ws_row - 3;
819 		else
820 			winlines = VMSTAT_DEFAULT_LINES;
821 		break;
822 	}
823 
824 	/*
825 	 * Inhibit doresize() calls until we are rescheduled by SIGWINCH.
826 	 */
827 	wresized = 0;
828 }
829 
830 #ifdef notyet
831 static void
832 dotimes(void)
833 {
834 	unsigned int pgintime, rectime;
835 
836 	kread(X_REC, &rectime, sizeof(rectime));
837 	kread(X_PGIN, &pgintime, sizeof(pgintime));
838 	kread(X_SUM, &sum, sizeof(sum));
839 	(void)printf("%u reclaims, %u total time (usec)\n",
840 	    sum.v_pgrec, rectime);
841 	(void)printf("average: %u usec / reclaim\n", rectime / sum.v_pgrec);
842 	(void)printf("\n");
843 	(void)printf("%u page ins, %u total time (msec)\n",
844 	    sum.v_pgin, pgintime / 10);
845 	(void)printf("average: %8.1f msec / page in\n",
846 	    pgintime / (sum.v_pgin * 10.0));
847 }
848 #endif
849 
850 static long
851 pct(long top, long bot)
852 {
853 	long ans;
854 
855 	if (bot == 0)
856 		return(0);
857 	ans = (quad_t)top * 100 / bot;
858 	return (ans);
859 }
860 
861 #define	PCT(top, bot) pct((long)(top), (long)(bot))
862 
863 static void
864 dosum(void)
865 {
866 	struct nchstats lnchstats;
867 	long nchtotal;
868 
869 	fill_vmmeter(&sum);
870 	(void)printf("%9u cpu context switches\n", sum.v_swtch);
871 	(void)printf("%9u device interrupts\n", sum.v_intr);
872 	(void)printf("%9u software interrupts\n", sum.v_soft);
873 	(void)printf("%9u traps\n", sum.v_trap);
874 	(void)printf("%9u system calls\n", sum.v_syscall);
875 	(void)printf("%9u kernel threads created\n", sum.v_kthreads);
876 	(void)printf("%9u  fork() calls\n", sum.v_forks);
877 	(void)printf("%9u vfork() calls\n", sum.v_vforks);
878 	(void)printf("%9u rfork() calls\n", sum.v_rforks);
879 	(void)printf("%9u swap pager pageins\n", sum.v_swapin);
880 	(void)printf("%9u swap pager pages paged in\n", sum.v_swappgsin);
881 	(void)printf("%9u swap pager pageouts\n", sum.v_swapout);
882 	(void)printf("%9u swap pager pages paged out\n", sum.v_swappgsout);
883 	(void)printf("%9u vnode pager pageins\n", sum.v_vnodein);
884 	(void)printf("%9u vnode pager pages paged in\n", sum.v_vnodepgsin);
885 	(void)printf("%9u vnode pager pageouts\n", sum.v_vnodeout);
886 	(void)printf("%9u vnode pager pages paged out\n", sum.v_vnodepgsout);
887 	(void)printf("%9u page daemon wakeups\n", sum.v_pdwakeups);
888 	(void)printf("%9u pages examined by the page daemon\n", sum.v_pdpages);
889 	(void)printf("%9u pages reactivated\n", sum.v_reactivated);
890 	(void)printf("%9u copy-on-write faults\n", sum.v_cow_faults);
891 	(void)printf("%9u copy-on-write optimized faults\n", sum.v_cow_optim);
892 	(void)printf("%9u zero fill pages zeroed\n", sum.v_zfod);
893 	(void)printf("%9u zero fill pages prezeroed\n", sum.v_ozfod);
894 	(void)printf("%9u intransit blocking page faults\n", sum.v_intrans);
895 	(void)printf("%9u total VM faults taken\n", sum.v_vm_faults);
896 	(void)printf("%9u pages affected by kernel thread creation\n", sum.v_kthreadpages);
897 	(void)printf("%9u pages affected by  fork()\n", sum.v_forkpages);
898 	(void)printf("%9u pages affected by vfork()\n", sum.v_vforkpages);
899 	(void)printf("%9u pages affected by rfork()\n", sum.v_rforkpages);
900 	(void)printf("%9u pages cached\n", sum.v_tcached);
901 	(void)printf("%9u pages freed\n", sum.v_tfree);
902 	(void)printf("%9u pages freed by daemon\n", sum.v_dfree);
903 	(void)printf("%9u pages freed by exiting processes\n", sum.v_pfree);
904 	(void)printf("%9u pages active\n", sum.v_active_count);
905 	(void)printf("%9u pages inactive\n", sum.v_inactive_count);
906 	(void)printf("%9u pages in VM cache\n", sum.v_cache_count);
907 	(void)printf("%9u pages wired down\n", sum.v_wire_count);
908 	(void)printf("%9u pages free\n", sum.v_free_count);
909 	(void)printf("%9u bytes per page\n", sum.v_page_size);
910 	if (kd != NULL) {
911 		kread(X_NCHSTATS, &lnchstats, sizeof(lnchstats));
912 	} else {
913 		size_t size = sizeof(lnchstats);
914 		mysysctl("vfs.cache.nchstats", &lnchstats, &size, NULL, 0);
915 		if (size != sizeof(lnchstats))
916 			errx(1, "vfs.cache.nchstats size mismatch");
917 	}
918 	nchtotal = lnchstats.ncs_goodhits + lnchstats.ncs_neghits +
919 	    lnchstats.ncs_badhits + lnchstats.ncs_falsehits +
920 	    lnchstats.ncs_miss + lnchstats.ncs_long;
921 	(void)printf("%9ld total name lookups\n", nchtotal);
922 	(void)printf(
923 	    "%9s cache hits (%ld%% pos + %ld%% neg) system %ld%% per-directory\n",
924 	    "", PCT(lnchstats.ncs_goodhits, nchtotal),
925 	    PCT(lnchstats.ncs_neghits, nchtotal),
926 	    PCT(lnchstats.ncs_pass2, nchtotal));
927 	(void)printf("%9s deletions %ld%%, falsehits %ld%%, toolong %ld%%\n", "",
928 	    PCT(lnchstats.ncs_badhits, nchtotal),
929 	    PCT(lnchstats.ncs_falsehits, nchtotal),
930 	    PCT(lnchstats.ncs_long, nchtotal));
931 }
932 
933 static void
934 doforkst(void)
935 {
936 	fill_vmmeter(&sum);
937 	(void)printf("%u forks, %u pages, average %.2f\n",
938 	    sum.v_forks, sum.v_forkpages,
939 	    sum.v_forks == 0 ? 0.0 :
940 	    (double)sum.v_forkpages / sum.v_forks);
941 	(void)printf("%u vforks, %u pages, average %.2f\n",
942 	    sum.v_vforks, sum.v_vforkpages,
943 	    sum.v_vforks == 0 ? 0.0 :
944 	    (double)sum.v_vforkpages / sum.v_vforks);
945 	(void)printf("%u rforks, %u pages, average %.2f\n",
946 	    sum.v_rforks, sum.v_rforkpages,
947 	    sum.v_rforks == 0 ? 0.0 :
948 	    (double)sum.v_rforkpages / sum.v_rforks);
949 }
950 
951 static void
952 devstats(void)
953 {
954 	int dn, state;
955 	long double transfers_per_second;
956 	long double busy_seconds;
957 	long tmp;
958 
959 	for (state = 0; state < CPUSTATES; ++state) {
960 		tmp = cur.cp_time[state];
961 		cur.cp_time[state] -= last.cp_time[state];
962 		last.cp_time[state] = tmp;
963 	}
964 
965 	busy_seconds = cur.snap_time - last.snap_time;
966 
967 	for (dn = 0; dn < num_devices; dn++) {
968 		int di;
969 
970 		if ((dev_select[dn].selected == 0)
971 		 || (dev_select[dn].selected > maxshowdevs))
972 			continue;
973 
974 		di = dev_select[dn].position;
975 
976 		if (devstat_compute_statistics(&cur.dinfo->devices[di],
977 		    &last.dinfo->devices[di], busy_seconds,
978 		    DSM_TRANSFERS_PER_SECOND, &transfers_per_second,
979 		    DSM_NONE) != 0)
980 			errx(1, "%s", devstat_errbuf);
981 
982 		(void)printf("%3.0Lf ", transfers_per_second);
983 	}
984 }
985 
986 static void
987 percent(double pct, int *over)
988 {
989 	char buf[10];
990 	int l;
991 
992 	l = snprintf(buf, sizeof(buf), "%.0f", pct);
993 	if (l == 1 && *over) {
994 		printf("%s",  buf);
995 		(*over)--;
996 	} else
997 		printf("%2s", buf);
998 	if (l > 2)
999 		(*over)++;
1000 }
1001 
1002 static void
1003 cpustats(void)
1004 {
1005 	int state, over;
1006 	double lpct, total;
1007 
1008 	total = 0;
1009 	for (state = 0; state < CPUSTATES; ++state)
1010 		total += cur.cp_time[state];
1011 	if (total)
1012 		lpct = 100.0 / total;
1013 	else
1014 		lpct = 0.0;
1015 	over = 0;
1016 	printf(" ");
1017 	percent((cur.cp_time[CP_USER] + cur.cp_time[CP_NICE]) * lpct, &over);
1018 	printf(" ");
1019 	percent((cur.cp_time[CP_SYS] + cur.cp_time[CP_INTR]) * lpct, &over);
1020 	printf(" ");
1021 	percent(cur.cp_time[CP_IDLE] * lpct, &over);
1022 }
1023 
1024 static void
1025 pcpustats(int ncpus, u_long cpumask, int maxid)
1026 {
1027 	int state, i;
1028 	double lpct, total;
1029 	long tmp;
1030 	int over;
1031 
1032 	/* devstats does this for cp_time */
1033 	for (i = 0; i <= maxid; i++) {
1034 		if ((cpumask & (1ul << i)) == 0)
1035 			continue;
1036 		for (state = 0; state < CPUSTATES; ++state) {
1037 			tmp = cur_cp_times[i * CPUSTATES + state];
1038 			cur_cp_times[i * CPUSTATES + state] -= last_cp_times[i * CPUSTATES + state];
1039 			last_cp_times[i * CPUSTATES + state] = tmp;
1040 		}
1041 	}
1042 
1043 	over = 0;
1044 	for (i = 0; i <= maxid; i++) {
1045 		if ((cpumask & (1ul << i)) == 0)
1046 			continue;
1047 		total = 0;
1048 		for (state = 0; state < CPUSTATES; ++state)
1049 			total += cur_cp_times[i * CPUSTATES + state];
1050 		if (total)
1051 			lpct = 100.0 / total;
1052 		else
1053 			lpct = 0.0;
1054 		printf(" ");
1055 		percent((cur_cp_times[i * CPUSTATES + CP_USER] +
1056 			 cur_cp_times[i * CPUSTATES + CP_NICE]) * lpct, &over);
1057 		printf(" ");
1058 		percent((cur_cp_times[i * CPUSTATES + CP_SYS] +
1059 			 cur_cp_times[i * CPUSTATES + CP_INTR]) * lpct, &over);
1060 		printf(" ");
1061 		percent(cur_cp_times[i * CPUSTATES + CP_IDLE] * lpct, &over);
1062 	}
1063 }
1064 
1065 static void
1066 dointr(void)
1067 {
1068 	unsigned long *intrcnt, uptime;
1069 	uint64_t inttotal;
1070 	size_t clen, inamlen, intrcntlen, istrnamlen;
1071 	unsigned int i, nintr;
1072 	char *intrname, *tintrname;
1073 
1074 	uptime = getuptime();
1075 	if (kd != NULL) {
1076 		intrcntlen = namelist[X_EINTRCNT].n_value -
1077 		    namelist[X_INTRCNT].n_value;
1078 		inamlen = namelist[X_EINTRNAMES].n_value -
1079 		    namelist[X_INTRNAMES].n_value;
1080 		if ((intrcnt = malloc(intrcntlen)) == NULL ||
1081 		    (intrname = malloc(inamlen)) == NULL)
1082 			err(1, "malloc()");
1083 		kread(X_INTRCNT, intrcnt, intrcntlen);
1084 		kread(X_INTRNAMES, intrname, inamlen);
1085 	} else {
1086 		for (intrcnt = NULL, intrcntlen = 1024; ; intrcntlen *= 2) {
1087 			if ((intrcnt = reallocf(intrcnt, intrcntlen)) == NULL)
1088 				err(1, "reallocf()");
1089 			if (mysysctl("hw.intrcnt",
1090 			    intrcnt, &intrcntlen, NULL, 0) == 0)
1091 				break;
1092 		}
1093 		for (intrname = NULL, inamlen = 1024; ; inamlen *= 2) {
1094 			if ((intrname = reallocf(intrname, inamlen)) == NULL)
1095 				err(1, "reallocf()");
1096 			if (mysysctl("hw.intrnames",
1097 			    intrname, &inamlen, NULL, 0) == 0)
1098 				break;
1099 		}
1100 	}
1101 	nintr = intrcntlen / sizeof(unsigned long);
1102 	tintrname = intrname;
1103 	istrnamlen = strlen("interrupt");
1104 	for (i = 0; i < nintr; i++) {
1105 		clen = strlen(tintrname);
1106 		if (clen > istrnamlen)
1107 			istrnamlen = clen;
1108 		tintrname += clen + 1;
1109 	}
1110 	(void)printf("%-*s %20s %10s\n", istrnamlen, "interrupt", "total",
1111 	    "rate");
1112 	inttotal = 0;
1113 	for (i = 0; i < nintr; i++) {
1114 		if (intrname[0] != '\0' && (*intrcnt != 0 || aflag))
1115 			(void)printf("%-*s %20lu %10lu\n", istrnamlen, intrname,
1116 			    *intrcnt, *intrcnt / uptime);
1117 		intrname += strlen(intrname) + 1;
1118 		inttotal += *intrcnt++;
1119 	}
1120 	(void)printf("%-*s %20llu %10llu\n", istrnamlen, "Total",
1121 	    (long long)inttotal, (long long)(inttotal / uptime));
1122 }
1123 
1124 static void
1125 domemstat_malloc(void)
1126 {
1127 	struct memory_type_list *mtlp;
1128 	struct memory_type *mtp;
1129 	int error, first, i;
1130 
1131 	mtlp = memstat_mtl_alloc();
1132 	if (mtlp == NULL) {
1133 		warn("memstat_mtl_alloc");
1134 		return;
1135 	}
1136 	if (kd == NULL) {
1137 		if (memstat_sysctl_malloc(mtlp, 0) < 0) {
1138 			warnx("memstat_sysctl_malloc: %s",
1139 			    memstat_strerror(memstat_mtl_geterror(mtlp)));
1140 			return;
1141 		}
1142 	} else {
1143 		if (memstat_kvm_malloc(mtlp, kd) < 0) {
1144 			error = memstat_mtl_geterror(mtlp);
1145 			if (error == MEMSTAT_ERROR_KVM)
1146 				warnx("memstat_kvm_malloc: %s",
1147 				    kvm_geterr(kd));
1148 			else
1149 				warnx("memstat_kvm_malloc: %s",
1150 				    memstat_strerror(error));
1151 		}
1152 	}
1153 	printf("%13s %5s %6s %7s %8s  Size(s)\n", "Type", "InUse", "MemUse",
1154 	    "HighUse", "Requests");
1155 	for (mtp = memstat_mtl_first(mtlp); mtp != NULL;
1156 	    mtp = memstat_mtl_next(mtp)) {
1157 		if (memstat_get_numallocs(mtp) == 0 &&
1158 		    memstat_get_count(mtp) == 0)
1159 			continue;
1160 		printf("%13s %5lld %5lldK %7s %8lld  ",
1161 		    memstat_get_name(mtp), memstat_get_count(mtp),
1162 		    ((int64_t)memstat_get_bytes(mtp) + 1023) / 1024, "-",
1163 		    memstat_get_numallocs(mtp));
1164 		first = 1;
1165 		for (i = 0; i < 32; i++) {
1166 			if (memstat_get_sizemask(mtp) & (1 << i)) {
1167 				if (!first)
1168 					printf(",");
1169 				printf("%d", 1 << (i + 4));
1170 				first = 0;
1171 			}
1172 		}
1173 		printf("\n");
1174 	}
1175 	memstat_mtl_free(mtlp);
1176 }
1177 
1178 static void
1179 domemstat_zone(void)
1180 {
1181 	struct memory_type_list *mtlp;
1182 	struct memory_type *mtp;
1183 	char name[MEMTYPE_MAXNAME + 1];
1184 	int error;
1185 
1186 	mtlp = memstat_mtl_alloc();
1187 	if (mtlp == NULL) {
1188 		warn("memstat_mtl_alloc");
1189 		return;
1190 	}
1191 	if (kd == NULL) {
1192 		if (memstat_sysctl_uma(mtlp, 0) < 0) {
1193 			warnx("memstat_sysctl_uma: %s",
1194 			    memstat_strerror(memstat_mtl_geterror(mtlp)));
1195 			return;
1196 		}
1197 	} else {
1198 		if (memstat_kvm_uma(mtlp, kd) < 0) {
1199 			error = memstat_mtl_geterror(mtlp);
1200 			if (error == MEMSTAT_ERROR_KVM)
1201 				warnx("memstat_kvm_uma: %s",
1202 				    kvm_geterr(kd));
1203 			else
1204 				warnx("memstat_kvm_uma: %s",
1205 				    memstat_strerror(error));
1206 		}
1207 	}
1208 	printf("%-20s %8s  %8s  %8s  %8s  %8s  %8s\n\n", "ITEM", "SIZE",
1209 	    "LIMIT", "USED", "FREE", "REQUESTS", "FAILURES");
1210 	for (mtp = memstat_mtl_first(mtlp); mtp != NULL;
1211 	    mtp = memstat_mtl_next(mtp)) {
1212 		strlcpy(name, memstat_get_name(mtp), MEMTYPE_MAXNAME);
1213 		strcat(name, ":");
1214 		printf("%-20s %8llu, %8llu, %8llu, %8llu, %8llu, %8llu\n", name,
1215 		    memstat_get_size(mtp), memstat_get_countlimit(mtp),
1216 		    memstat_get_count(mtp), memstat_get_free(mtp),
1217 		    memstat_get_numallocs(mtp), memstat_get_failures(mtp));
1218 	}
1219 	memstat_mtl_free(mtlp);
1220 	printf("\n");
1221 }
1222 
1223 /*
1224  * kread reads something from the kernel, given its nlist index.
1225  */
1226 static void
1227 kreado(int nlx, void *addr, size_t size, size_t offset)
1228 {
1229 	const char *sym;
1230 
1231 	if (namelist[nlx].n_type == 0 || namelist[nlx].n_value == 0) {
1232 		sym = namelist[nlx].n_name;
1233 		if (*sym == '_')
1234 			++sym;
1235 		errx(1, "symbol %s not defined", sym);
1236 	}
1237 	if ((size_t)kvm_read(kd, namelist[nlx].n_value + offset, addr,
1238 	    size) != size) {
1239 		sym = namelist[nlx].n_name;
1240 		if (*sym == '_')
1241 			++sym;
1242 		errx(1, "%s: %s", sym, kvm_geterr(kd));
1243 	}
1244 }
1245 
1246 static void
1247 kread(int nlx, void *addr, size_t size)
1248 {
1249 	kreado(nlx, addr, size, 0);
1250 }
1251 
1252 static char *
1253 kgetstr(const char *strp)
1254 {
1255 	int n = 0, size = 1;
1256 	char *ret = NULL;
1257 
1258 	do {
1259 		if (size == n + 1) {
1260 			ret = realloc(ret, size);
1261 			if (ret == NULL)
1262 				err(1, "%s: realloc", __func__);
1263 			size *= 2;
1264 		}
1265 		if (kvm_read(kd, (u_long)strp + n, &ret[n], 1) != 1)
1266 			errx(1, "%s: %s", __func__, kvm_geterr(kd));
1267 	} while (ret[n++] != '\0');
1268 	return (ret);
1269 }
1270 
1271 static void
1272 usage(void)
1273 {
1274 	(void)fprintf(stderr, "%s%s",
1275 		"usage: vmstat [-afHhimPsz] [-c count] [-M core [-N system]] [-w wait]\n",
1276 		"              [-n devs] [-p type,if,pass] [disks]\n");
1277 	exit(1);
1278 }
1279