xref: /freebsd/lib/libdevstat/devstat.c (revision 17d6c636720d00f77e5d098daf4c278f89d84f7b)
1 /*
2  * Copyright (c) 1997, 1998 Kenneth D. Merry.
3  * 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. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/types.h>
33 #include <sys/sysctl.h>
34 #include <sys/errno.h>
35 #include <sys/dkstat.h>
36 #include <sys/queue.h>
37 
38 #include <ctype.h>
39 #include <err.h>
40 #include <fcntl.h>
41 #include <limits.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <stdarg.h>
46 #include <kvm.h>
47 
48 #include "devstat.h"
49 
50 typedef enum {
51 	DEVSTAT_ARG_NOTYPE,
52 	DEVSTAT_ARG_UINT64,
53 	DEVSTAT_ARG_LD,
54 	DEVSTAT_ARG_SKIP
55 } devstat_arg_type;
56 
57 char devstat_errbuf[DEVSTAT_ERRBUF_SIZE];
58 
59 /*
60  * Table to match descriptive strings with device types.  These are in
61  * order from most common to least common to speed search time.
62  */
63 struct devstat_match_table match_table[] = {
64 	{"da",		DEVSTAT_TYPE_DIRECT,	DEVSTAT_MATCH_TYPE},
65 	{"cd",		DEVSTAT_TYPE_CDROM,	DEVSTAT_MATCH_TYPE},
66 	{"scsi",	DEVSTAT_TYPE_IF_SCSI,	DEVSTAT_MATCH_IF},
67 	{"ide",		DEVSTAT_TYPE_IF_IDE,	DEVSTAT_MATCH_IF},
68 	{"other",	DEVSTAT_TYPE_IF_OTHER,	DEVSTAT_MATCH_IF},
69 	{"worm",	DEVSTAT_TYPE_WORM,	DEVSTAT_MATCH_TYPE},
70 	{"sa",		DEVSTAT_TYPE_SEQUENTIAL,DEVSTAT_MATCH_TYPE},
71 	{"pass",	DEVSTAT_TYPE_PASS,	DEVSTAT_MATCH_PASS},
72 	{"optical",	DEVSTAT_TYPE_OPTICAL,	DEVSTAT_MATCH_TYPE},
73 	{"array",	DEVSTAT_TYPE_STORARRAY,	DEVSTAT_MATCH_TYPE},
74 	{"changer",	DEVSTAT_TYPE_CHANGER,	DEVSTAT_MATCH_TYPE},
75 	{"scanner",	DEVSTAT_TYPE_SCANNER,	DEVSTAT_MATCH_TYPE},
76 	{"printer",	DEVSTAT_TYPE_PRINTER,	DEVSTAT_MATCH_TYPE},
77 	{"floppy",	DEVSTAT_TYPE_FLOPPY,	DEVSTAT_MATCH_TYPE},
78 	{"proc",	DEVSTAT_TYPE_PROCESSOR,	DEVSTAT_MATCH_TYPE},
79 	{"comm",	DEVSTAT_TYPE_COMM,	DEVSTAT_MATCH_TYPE},
80 	{"enclosure",	DEVSTAT_TYPE_ENCLOSURE,	DEVSTAT_MATCH_TYPE},
81 	{NULL,		0,			0}
82 };
83 
84 struct devstat_args {
85 	devstat_metric 		metric;
86 	devstat_arg_type	argtype;
87 } devstat_arg_list[] = {
88 	{ DSM_NONE, DEVSTAT_ARG_NOTYPE },
89 	{ DSM_TOTAL_BYTES, DEVSTAT_ARG_UINT64 },
90 	{ DSM_TOTAL_BYTES_READ, DEVSTAT_ARG_UINT64 },
91 	{ DSM_TOTAL_BYTES_WRITE, DEVSTAT_ARG_UINT64 },
92 	{ DSM_TOTAL_TRANSFERS, DEVSTAT_ARG_UINT64 },
93 	{ DSM_TOTAL_TRANSFERS_READ, DEVSTAT_ARG_UINT64 },
94 	{ DSM_TOTAL_TRANSFERS_WRITE, DEVSTAT_ARG_UINT64 },
95 	{ DSM_TOTAL_TRANSFERS_OTHER, DEVSTAT_ARG_UINT64 },
96 	{ DSM_TOTAL_BLOCKS, DEVSTAT_ARG_UINT64 },
97 	{ DSM_TOTAL_BLOCKS_READ, DEVSTAT_ARG_UINT64 },
98 	{ DSM_TOTAL_BLOCKS_WRITE, DEVSTAT_ARG_UINT64 },
99 	{ DSM_KB_PER_TRANSFER, DEVSTAT_ARG_LD },
100 	{ DSM_KB_PER_TRANSFER_READ, DEVSTAT_ARG_LD },
101 	{ DSM_KB_PER_TRANSFER_WRITE, DEVSTAT_ARG_LD },
102 	{ DSM_TRANSFERS_PER_SECOND, DEVSTAT_ARG_LD },
103 	{ DSM_TRANSFERS_PER_SECOND_READ, DEVSTAT_ARG_LD },
104 	{ DSM_TRANSFERS_PER_SECOND_WRITE, DEVSTAT_ARG_LD },
105 	{ DSM_TRANSFERS_PER_SECOND_OTHER, DEVSTAT_ARG_LD },
106 	{ DSM_MB_PER_SECOND, DEVSTAT_ARG_LD },
107 	{ DSM_MB_PER_SECOND_READ, DEVSTAT_ARG_LD },
108 	{ DSM_MB_PER_SECOND_WRITE, DEVSTAT_ARG_LD },
109 	{ DSM_BLOCKS_PER_SECOND, DEVSTAT_ARG_LD },
110 	{ DSM_BLOCKS_PER_SECOND_READ, DEVSTAT_ARG_LD },
111 	{ DSM_BLOCKS_PER_SECOND_WRITE, DEVSTAT_ARG_LD },
112 	{ DSM_MS_PER_TRANSACTION, DEVSTAT_ARG_LD },
113 	{ DSM_MS_PER_TRANSACTION_READ, DEVSTAT_ARG_LD },
114 	{ DSM_MS_PER_TRANSACTION_WRITE, DEVSTAT_ARG_LD },
115 	{ DSM_SKIP, DEVSTAT_ARG_SKIP }
116 };
117 
118 static const char *namelist[] = {
119 #define X_NUMDEVS	0
120 	"_devstat_num_devs",
121 #define X_GENERATION	1
122 	"_devstat_generation",
123 #define X_VERSION	2
124 	"_devstat_version",
125 #define X_DEVICE_STATQ	3
126 	"_device_statq",
127 #define X_END		4
128 };
129 
130 /*
131  * Local function declarations.
132  */
133 static int compare_select(const void *arg1, const void *arg2);
134 static int readkmem(kvm_t *kd, unsigned long addr, void *buf, size_t nbytes);
135 static int readkmem_nl(kvm_t *kd, const char *name, void *buf, size_t nbytes);
136 static char *get_devstat_kvm(kvm_t *kd);
137 
138 #define KREADNL(kd, var, val) \
139 	readkmem_nl(kd, namelist[var], &val, sizeof(val))
140 
141 int
142 devstat_getnumdevs(kvm_t *kd)
143 {
144 	size_t numdevsize;
145 	int numdevs;
146 	const char *func_name = "devstat_getnumdevs";
147 
148 	numdevsize = sizeof(int);
149 
150 	/*
151 	 * Find out how many devices we have in the system.
152 	 */
153 	if (kd == NULL) {
154 		if (sysctlbyname("kern.devstat.numdevs", &numdevs,
155 				 &numdevsize, NULL, 0) == -1) {
156 			snprintf(devstat_errbuf, sizeof(devstat_errbuf),
157 				 "%s: error getting number of devices\n"
158 				 "%s: %s", func_name, func_name,
159 				 strerror(errno));
160 			return(-1);
161 		} else
162 			return(numdevs);
163 	} else {
164 
165 		if (KREADNL(kd, X_NUMDEVS, numdevs) == -1)
166 			return(-1);
167 		else
168 			return(numdevs);
169 	}
170 }
171 
172 /*
173  * This is an easy way to get the generation number, but the generation is
174  * supplied in a more atmoic manner by the kern.devstat.all sysctl.
175  * Because this generation sysctl is separate from the statistics sysctl,
176  * the device list and the generation could change between the time that
177  * this function is called and the device list is retreived.
178  */
179 long
180 devstat_getgeneration(kvm_t *kd)
181 {
182 	size_t gensize;
183 	long generation;
184 	const char *func_name = "devstat_getgeneration";
185 
186 	gensize = sizeof(long);
187 
188 	/*
189 	 * Get the current generation number.
190 	 */
191 	if (kd == NULL) {
192 		if (sysctlbyname("kern.devstat.generation", &generation,
193 				 &gensize, NULL, 0) == -1) {
194 			snprintf(devstat_errbuf, sizeof(devstat_errbuf),
195 				 "%s: error getting devstat generation\n%s: %s",
196 				 func_name, func_name, strerror(errno));
197 			return(-1);
198 		} else
199 			return(generation);
200 	} else {
201 		if (KREADNL(kd, X_GENERATION, generation) == -1)
202 			return(-1);
203 		else
204 			return(generation);
205 	}
206 }
207 
208 /*
209  * Get the current devstat version.  The return value of this function
210  * should be compared with DEVSTAT_VERSION, which is defined in
211  * sys/devicestat.h.  This will enable userland programs to determine
212  * whether they are out of sync with the kernel.
213  */
214 int
215 devstat_getversion(kvm_t *kd)
216 {
217 	size_t versize;
218 	int version;
219 	const char *func_name = "devstat_getversion";
220 
221 	versize = sizeof(int);
222 
223 	/*
224 	 * Get the current devstat version.
225 	 */
226 	if (kd == NULL) {
227 		if (sysctlbyname("kern.devstat.version", &version, &versize,
228 				 NULL, 0) == -1) {
229 			snprintf(devstat_errbuf, sizeof(devstat_errbuf),
230 				 "%s: error getting devstat version\n%s: %s",
231 				 func_name, func_name, strerror(errno));
232 			return(-1);
233 		} else
234 			return(version);
235 	} else {
236 		if (KREADNL(kd, X_VERSION, version) == -1)
237 			return(-1);
238 		else
239 			return(version);
240 	}
241 }
242 
243 /*
244  * Check the devstat version we know about against the devstat version the
245  * kernel knows about.  If they don't match, print an error into the
246  * devstat error buffer, and return -1.  If they match, return 0.
247  */
248 int
249 devstat_checkversion(kvm_t *kd)
250 {
251 	const char *func_name = "devstat_checkversion";
252 	int buflen, res, retval = 0, version;
253 
254 	version = devstat_getversion(kd);
255 
256 	if (version != DEVSTAT_VERSION) {
257 		/*
258 		 * If getversion() returns an error (i.e. -1), then it
259 		 * has printed an error message in the buffer.  Therefore,
260 		 * we need to add a \n to the end of that message before we
261 		 * print our own message in the buffer.
262 		 */
263 		if (version == -1)
264 			buflen = strlen(devstat_errbuf);
265 		else
266 			buflen = 0;
267 
268 		res = snprintf(devstat_errbuf + buflen,
269 			       DEVSTAT_ERRBUF_SIZE - buflen,
270 			       "%s%s: userland devstat version %d is not "
271 			       "the same as the kernel\n%s: devstat "
272 			       "version %d\n", version == -1 ? "\n" : "",
273 			       func_name, DEVSTAT_VERSION, func_name, version);
274 
275 		if (res < 0)
276 			devstat_errbuf[buflen] = '\0';
277 
278 		buflen = strlen(devstat_errbuf);
279 		if (version < DEVSTAT_VERSION)
280 			res = snprintf(devstat_errbuf + buflen,
281 				       DEVSTAT_ERRBUF_SIZE - buflen,
282 				       "%s: libdevstat newer than kernel\n",
283 				       func_name);
284 		else
285 			res = snprintf(devstat_errbuf + buflen,
286 				       DEVSTAT_ERRBUF_SIZE - buflen,
287 				       "%s: kernel newer than libdevstat\n",
288 				       func_name);
289 
290 		if (res < 0)
291 			devstat_errbuf[buflen] = '\0';
292 
293 		retval = -1;
294 	}
295 
296 	return(retval);
297 }
298 
299 /*
300  * Get the current list of devices and statistics, and the current
301  * generation number.
302  *
303  * Return values:
304  * -1  -- error
305  *  0  -- device list is unchanged
306  *  1  -- device list has changed
307  */
308 int
309 devstat_getdevs(kvm_t *kd, struct statinfo *stats)
310 {
311 	int error;
312 	size_t dssize;
313 	int oldnumdevs;
314 	long oldgeneration;
315 	int retval = 0;
316 	struct devinfo *dinfo;
317 	const char *func_name = "devstat_getdevs";
318 
319 	dinfo = stats->dinfo;
320 
321 	if (dinfo == NULL) {
322 		snprintf(devstat_errbuf, sizeof(devstat_errbuf),
323 			 "%s: stats->dinfo was NULL", func_name);
324 		return(-1);
325 	}
326 
327 	oldnumdevs = dinfo->numdevs;
328 	oldgeneration = dinfo->generation;
329 
330 	/* Get the current time when we get the stats */
331 	gettimeofday(&stats->busy_time, NULL);
332 
333 	if (kd == NULL) {
334 		/* If this is our first time through, mem_ptr will be null. */
335 		if (dinfo->mem_ptr == NULL) {
336 			/*
337 			 * Get the number of devices.  If it's negative, it's an
338 			 * error.  Don't bother setting the error string, since
339 			 * getnumdevs() has already done that for us.
340 			 */
341 			if ((dinfo->numdevs = getnumdevs()) < 0)
342 				return(-1);
343 
344 			/*
345 			 * The kern.devstat.all sysctl returns the current
346 			 * generation number, as well as all the devices.
347 			 * So we need four bytes more.
348 			 */
349 			dssize = (dinfo->numdevs * sizeof(struct devstat)) +
350 				 sizeof(long);
351 			dinfo->mem_ptr = (u_int8_t *)malloc(dssize);
352 		} else
353 			dssize = (dinfo->numdevs * sizeof(struct devstat)) +
354 				 sizeof(long);
355 
356 		/*
357 		 * Request all of the devices.  We only really allow for one
358 		 * ENOMEM failure.  It would, of course, be possible to just go
359 		 * in a loop and keep reallocing the device structure until we
360 		 * don't get ENOMEM back.  I'm not sure it's worth it, though.
361 		 * If devices are being added to the system that quickly, maybe
362 		 * the user can just wait until all devices are added.
363 		 */
364 		if ((error = sysctlbyname("kern.devstat.all", dinfo->mem_ptr,
365 					  &dssize, NULL, 0)) == -1) {
366 			/*
367 			 * If we get ENOMEM back, that means that there are
368 			 * more devices now, so we need to allocate more
369 			 * space for the device array.
370 			 */
371 			if (errno == ENOMEM) {
372 				/*
373 				 * No need to set the error string here,
374 				 * getnumdevs() will do that if it fails.
375 				 */
376 				if ((dinfo->numdevs = getnumdevs()) < 0)
377 					return(-1);
378 
379 				dssize = (dinfo->numdevs *
380 					sizeof(struct devstat)) + sizeof(long);
381 				dinfo->mem_ptr = (u_int8_t *)
382 					realloc(dinfo->mem_ptr, dssize);
383 				if ((error = sysctlbyname("kern.devstat.all",
384 				    dinfo->mem_ptr, &dssize, NULL, 0)) == -1) {
385 					snprintf(devstat_errbuf,
386 						 sizeof(devstat_errbuf),
387 					    	 "%s: error getting device "
388 					    	 "stats\n%s: %s", func_name,
389 					    	 func_name, strerror(errno));
390 					return(-1);
391 				}
392 			} else {
393 				snprintf(devstat_errbuf, sizeof(devstat_errbuf),
394 					 "%s: error getting device stats\n"
395 					 "%s: %s", func_name, func_name,
396 					 strerror(errno));
397 				return(-1);
398 			}
399 		}
400 
401 	} else {
402 		/*
403 		 * This is of course non-atomic, but since we are working
404 		 * on a core dump, the generation is unlikely to change
405 		 */
406 		if ((dinfo->numdevs = getnumdevs()) == -1)
407 			return(-1);
408 		if ((dinfo->mem_ptr = get_devstat_kvm(kd)) == NULL)
409 			return(-1);
410 	}
411 	/*
412 	 * The sysctl spits out the generation as the first four bytes,
413 	 * then all of the device statistics structures.
414 	 */
415 	dinfo->generation = *(long *)dinfo->mem_ptr;
416 
417 	/*
418 	 * If the generation has changed, and if the current number of
419 	 * devices is not the same as the number of devices recorded in the
420 	 * devinfo structure, it is likely that the device list has shrunk.
421 	 * The reason that it is likely that the device list has shrunk in
422 	 * this case is that if the device list has grown, the sysctl above
423 	 * will return an ENOMEM error, and we will reset the number of
424 	 * devices and reallocate the device array.  If the second sysctl
425 	 * fails, we will return an error and therefore never get to this
426 	 * point.  If the device list has shrunk, the sysctl will not
427 	 * return an error since we have more space allocated than is
428 	 * necessary.  So, in the shrinkage case, we catch it here and
429 	 * reallocate the array so that we don't use any more space than is
430 	 * necessary.
431 	 */
432 	if (oldgeneration != dinfo->generation) {
433 		if (getnumdevs() != dinfo->numdevs) {
434 			if ((dinfo->numdevs = getnumdevs()) < 0)
435 				return(-1);
436 			dssize = (dinfo->numdevs * sizeof(struct devstat)) +
437 				sizeof(long);
438 			dinfo->mem_ptr = (u_int8_t *)realloc(dinfo->mem_ptr,
439 							     dssize);
440 		}
441 		retval = 1;
442 	}
443 
444 	dinfo->devices = (struct devstat *)(dinfo->mem_ptr + sizeof(long));
445 
446 	return(retval);
447 }
448 
449 /*
450  * selectdevs():
451  *
452  * Devices are selected/deselected based upon the following criteria:
453  * - devices specified by the user on the command line
454  * - devices matching any device type expressions given on the command line
455  * - devices with the highest I/O, if 'top' mode is enabled
456  * - the first n unselected devices in the device list, if maxshowdevs
457  *   devices haven't already been selected and if the user has not
458  *   specified any devices on the command line and if we're in "add" mode.
459  *
460  * Input parameters:
461  * - device selection list (dev_select)
462  * - current number of devices selected (num_selected)
463  * - total number of devices in the selection list (num_selections)
464  * - devstat generation as of the last time selectdevs() was called
465  *   (select_generation)
466  * - current devstat generation (current_generation)
467  * - current list of devices and statistics (devices)
468  * - number of devices in the current device list (numdevs)
469  * - compiled version of the command line device type arguments (matches)
470  *   - This is optional.  If the number of devices is 0, this will be ignored.
471  *   - The matching code pays attention to the current selection mode.  So
472  *     if you pass in a matching expression, it will be evaluated based
473  *     upon the selection mode that is passed in.  See below for details.
474  * - number of device type matching expressions (num_matches)
475  *   - Set to 0 to disable the matching code.
476  * - list of devices specified on the command line by the user (dev_selections)
477  * - number of devices selected on the command line by the user
478  *   (num_dev_selections)
479  * - Our selection mode.  There are four different selection modes:
480  *      - add mode.  (DS_SELECT_ADD) Any devices matching devices explicitly
481  *        selected by the user or devices matching a pattern given by the
482  *        user will be selected in addition to devices that are already
483  *        selected.  Additional devices will be selected, up to maxshowdevs
484  *        number of devices.
485  *      - only mode. (DS_SELECT_ONLY)  Only devices matching devices
486  *        explicitly given by the user or devices matching a pattern
487  *        given by the user will be selected.  No other devices will be
488  *        selected.
489  *      - addonly mode.  (DS_SELECT_ADDONLY)  This is similar to add and
490  *        only.  Basically, this will not de-select any devices that are
491  *        current selected, as only mode would, but it will also not
492  *        gratuitously select up to maxshowdevs devices as add mode would.
493  *      - remove mode.  (DS_SELECT_REMOVE)  Any devices matching devices
494  *        explicitly selected by the user or devices matching a pattern
495  *        given by the user will be de-selected.
496  * - maximum number of devices we can select (maxshowdevs)
497  * - flag indicating whether or not we're in 'top' mode (perf_select)
498  *
499  * Output data:
500  * - the device selection list may be modified and passed back out
501  * - the number of devices selected and the total number of items in the
502  *   device selection list may be changed
503  * - the selection generation may be changed to match the current generation
504  *
505  * Return values:
506  * -1  -- error
507  *  0  -- selected devices are unchanged
508  *  1  -- selected devices changed
509  */
510 int
511 devstat_selectdevs(struct device_selection **dev_select, int *num_selected,
512 		   int *num_selections, long *select_generation,
513 		   long current_generation, struct devstat *devices,
514 		   int numdevs, struct devstat_match *matches, int num_matches,
515 		   char **dev_selections, int num_dev_selections,
516 		   devstat_select_mode select_mode, int maxshowdevs,
517 		   int perf_select)
518 {
519 	register int i, j, k;
520 	int init_selections = 0, init_selected_var = 0;
521 	struct device_selection *old_dev_select = NULL;
522 	int old_num_selections = 0, old_num_selected;
523 	int selection_number = 0;
524 	int changed = 0, found = 0;
525 
526 	if ((dev_select == NULL) || (devices == NULL) || (numdevs <= 0))
527 		return(-1);
528 
529 	/*
530 	 * We always want to make sure that we have as many dev_select
531 	 * entries as there are devices.
532 	 */
533 	/*
534 	 * In this case, we haven't selected devices before.
535 	 */
536 	if (*dev_select == NULL) {
537 		*dev_select = (struct device_selection *)malloc(numdevs *
538 			sizeof(struct device_selection));
539 		*select_generation = current_generation;
540 		init_selections = 1;
541 		changed = 1;
542 	/*
543 	 * In this case, we have selected devices before, but the device
544 	 * list has changed since we last selected devices, so we need to
545 	 * either enlarge or reduce the size of the device selection list.
546 	 */
547 	} else if (*num_selections != numdevs) {
548 		*dev_select = (struct device_selection *)realloc(*dev_select,
549 			numdevs * sizeof(struct device_selection));
550 		*select_generation = current_generation;
551 		init_selections = 1;
552 	/*
553 	 * In this case, we've selected devices before, and the selection
554 	 * list is the same size as it was the last time, but the device
555 	 * list has changed.
556 	 */
557 	} else if (*select_generation < current_generation) {
558 		*select_generation = current_generation;
559 		init_selections = 1;
560 	}
561 
562 	/*
563 	 * If we're in "only" mode, we want to clear out the selected
564 	 * variable since we're going to select exactly what the user wants
565 	 * this time through.
566 	 */
567 	if (select_mode == DS_SELECT_ONLY)
568 		init_selected_var = 1;
569 
570 	/*
571 	 * In all cases, we want to back up the number of selected devices.
572 	 * It is a quick and accurate way to determine whether the selected
573 	 * devices have changed.
574 	 */
575 	old_num_selected = *num_selected;
576 
577 	/*
578 	 * We want to make a backup of the current selection list if
579 	 * the list of devices has changed, or if we're in performance
580 	 * selection mode.  In both cases, we don't want to make a backup
581 	 * if we already know for sure that the list will be different.
582 	 * This is certainly the case if this is our first time through the
583 	 * selection code.
584 	 */
585 	if (((init_selected_var != 0) || (init_selections != 0)
586 	 || (perf_select != 0)) && (changed == 0)){
587 		old_dev_select = (struct device_selection *)malloc(
588 		    *num_selections * sizeof(struct device_selection));
589 		old_num_selections = *num_selections;
590 		bcopy(*dev_select, old_dev_select,
591 		    sizeof(struct device_selection) * *num_selections);
592 	}
593 
594 	if (init_selections != 0) {
595 		bzero(*dev_select, sizeof(struct device_selection) * numdevs);
596 
597 		for (i = 0; i < numdevs; i++) {
598 			(*dev_select)[i].device_number =
599 				devices[i].device_number;
600 			strncpy((*dev_select)[i].device_name,
601 				devices[i].device_name,
602 				DEVSTAT_NAME_LEN);
603 			(*dev_select)[i].device_name[DEVSTAT_NAME_LEN - 1]='\0';
604 			(*dev_select)[i].unit_number = devices[i].unit_number;
605 			(*dev_select)[i].position = i;
606 		}
607 		*num_selections = numdevs;
608 	} else if (init_selected_var != 0) {
609 		for (i = 0; i < numdevs; i++)
610 			(*dev_select)[i].selected = 0;
611 	}
612 
613 	/* we haven't gotten around to selecting anything yet.. */
614 	if ((select_mode == DS_SELECT_ONLY) || (init_selections != 0)
615 	 || (init_selected_var != 0))
616 		*num_selected = 0;
617 
618 	/*
619 	 * Look through any devices the user specified on the command line
620 	 * and see if they match known devices.  If so, select them.
621 	 */
622 	for (i = 0; (i < *num_selections) && (num_dev_selections > 0); i++) {
623 		char tmpstr[80];
624 
625 		snprintf(tmpstr, sizeof(tmpstr), "%s%d",
626 			 (*dev_select)[i].device_name,
627 			 (*dev_select)[i].unit_number);
628 		for (j = 0; j < num_dev_selections; j++) {
629 			if (strcmp(tmpstr, dev_selections[j]) == 0) {
630 				/*
631 				 * Here we do different things based on the
632 				 * mode we're in.  If we're in add or
633 				 * addonly mode, we only select this device
634 				 * if it hasn't already been selected.
635 				 * Otherwise, we would be unnecessarily
636 				 * changing the selection order and
637 				 * incrementing the selection count.  If
638 				 * we're in only mode, we unconditionally
639 				 * select this device, since in only mode
640 				 * any previous selections are erased and
641 				 * manually specified devices are the first
642 				 * ones to be selected.  If we're in remove
643 				 * mode, we de-select the specified device and
644 				 * decrement the selection count.
645 				 */
646 				switch(select_mode) {
647 				case DS_SELECT_ADD:
648 				case DS_SELECT_ADDONLY:
649 					if ((*dev_select)[i].selected)
650 						break;
651 					/* FALLTHROUGH */
652 				case DS_SELECT_ONLY:
653 					(*dev_select)[i].selected =
654 						++selection_number;
655 					(*num_selected)++;
656 					break;
657 				case DS_SELECT_REMOVE:
658 					(*dev_select)[i].selected = 0;
659 					(*num_selected)--;
660 					/*
661 					 * This isn't passed back out, we
662 					 * just use it to keep track of
663 					 * how many devices we've removed.
664 					 */
665 					num_dev_selections--;
666 					break;
667 				}
668 				break;
669 			}
670 		}
671 	}
672 
673 	/*
674 	 * Go through the user's device type expressions and select devices
675 	 * accordingly.  We only do this if the number of devices already
676 	 * selected is less than the maximum number we can show.
677 	 */
678 	for (i = 0; (i < num_matches) && (*num_selected < maxshowdevs); i++) {
679 		/* We should probably indicate some error here */
680 		if ((matches[i].match_fields == DEVSTAT_MATCH_NONE)
681 		 || (matches[i].num_match_categories <= 0))
682 			continue;
683 
684 		for (j = 0; j < numdevs; j++) {
685 			int num_match_categories;
686 
687 			num_match_categories = matches[i].num_match_categories;
688 
689 			/*
690 			 * Determine whether or not the current device
691 			 * matches the given matching expression.  This if
692 			 * statement consists of three components:
693 			 *   - the device type check
694 			 *   - the device interface check
695 			 *   - the passthrough check
696 			 * If a the matching test is successful, it
697 			 * decrements the number of matching categories,
698 			 * and if we've reached the last element that
699 			 * needed to be matched, the if statement succeeds.
700 			 *
701 			 */
702 			if ((((matches[i].match_fields & DEVSTAT_MATCH_TYPE)!=0)
703 			  && ((devices[j].device_type & DEVSTAT_TYPE_MASK) ==
704 			        (matches[i].device_type & DEVSTAT_TYPE_MASK))
705 			  &&(((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
706 			   || (((matches[i].match_fields &
707 				DEVSTAT_MATCH_PASS) == 0)
708 			    && ((devices[j].device_type &
709 			        DEVSTAT_TYPE_PASS) == 0)))
710 			  && (--num_match_categories == 0))
711 			 || (((matches[i].match_fields & DEVSTAT_MATCH_IF) != 0)
712 			  && ((devices[j].device_type & DEVSTAT_TYPE_IF_MASK) ==
713 			        (matches[i].device_type & DEVSTAT_TYPE_IF_MASK))
714 			  &&(((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
715 			   || (((matches[i].match_fields &
716 				DEVSTAT_MATCH_PASS) == 0)
717 			    && ((devices[j].device_type &
718 				DEVSTAT_TYPE_PASS) == 0)))
719 			  && (--num_match_categories == 0))
720 			 || (((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
721 			  && ((devices[j].device_type & DEVSTAT_TYPE_PASS) != 0)
722 			  && (--num_match_categories == 0))) {
723 
724 				/*
725 				 * This is probably a non-optimal solution
726 				 * to the problem that the devices in the
727 				 * device list will not be in the same
728 				 * order as the devices in the selection
729 				 * array.
730 				 */
731 				for (k = 0; k < numdevs; k++) {
732 					if ((*dev_select)[k].position == j) {
733 						found = 1;
734 						break;
735 					}
736 				}
737 
738 				/*
739 				 * There shouldn't be a case where a device
740 				 * in the device list is not in the
741 				 * selection list...but it could happen.
742 				 */
743 				if (found != 1) {
744 					fprintf(stderr, "selectdevs: couldn't"
745 						" find %s%d in selection "
746 						"list\n",
747 						devices[j].device_name,
748 						devices[j].unit_number);
749 					break;
750 				}
751 
752 				/*
753 				 * We do different things based upon the
754 				 * mode we're in.  If we're in add or only
755 				 * mode, we go ahead and select this device
756 				 * if it hasn't already been selected.  If
757 				 * it has already been selected, we leave
758 				 * it alone so we don't mess up the
759 				 * selection ordering.  Manually specified
760 				 * devices have already been selected, and
761 				 * they have higher priority than pattern
762 				 * matched devices.  If we're in remove
763 				 * mode, we de-select the given device and
764 				 * decrement the selected count.
765 				 */
766 				switch(select_mode) {
767 				case DS_SELECT_ADD:
768 				case DS_SELECT_ADDONLY:
769 				case DS_SELECT_ONLY:
770 					if ((*dev_select)[k].selected != 0)
771 						break;
772 					(*dev_select)[k].selected =
773 						++selection_number;
774 					(*num_selected)++;
775 					break;
776 				case DS_SELECT_REMOVE:
777 					(*dev_select)[k].selected = 0;
778 					(*num_selected)--;
779 					break;
780 				}
781 			}
782 		}
783 	}
784 
785 	/*
786 	 * Here we implement "top" mode.  Devices are sorted in the
787 	 * selection array based on two criteria:  whether or not they are
788 	 * selected (not selection number, just the fact that they are
789 	 * selected!) and the number of bytes in the "bytes" field of the
790 	 * selection structure.  The bytes field generally must be kept up
791 	 * by the user.  In the future, it may be maintained by library
792 	 * functions, but for now the user has to do the work.
793 	 *
794 	 * At first glance, it may seem wrong that we don't go through and
795 	 * select every device in the case where the user hasn't specified
796 	 * any devices or patterns.  In fact, though, it won't make any
797 	 * difference in the device sorting.  In that particular case (i.e.
798 	 * when we're in "add" or "only" mode, and the user hasn't
799 	 * specified anything) the first time through no devices will be
800 	 * selected, so the only criterion used to sort them will be their
801 	 * performance.  The second time through, and every time thereafter,
802 	 * all devices will be selected, so again selection won't matter.
803 	 */
804 	if (perf_select != 0) {
805 
806 		/* Sort the device array by throughput  */
807 		qsort(*dev_select, *num_selections,
808 		      sizeof(struct device_selection),
809 		      compare_select);
810 
811 		if (*num_selected == 0) {
812 			/*
813 			 * Here we select every device in the array, if it
814 			 * isn't already selected.  Because the 'selected'
815 			 * variable in the selection array entries contains
816 			 * the selection order, the devstats routine can show
817 			 * the devices that were selected first.
818 			 */
819 			for (i = 0; i < *num_selections; i++) {
820 				if ((*dev_select)[i].selected == 0) {
821 					(*dev_select)[i].selected =
822 						++selection_number;
823 					(*num_selected)++;
824 				}
825 			}
826 		} else {
827 			selection_number = 0;
828 			for (i = 0; i < *num_selections; i++) {
829 				if ((*dev_select)[i].selected != 0) {
830 					(*dev_select)[i].selected =
831 						++selection_number;
832 				}
833 			}
834 		}
835 	}
836 
837 	/*
838 	 * If we're in the "add" selection mode and if we haven't already
839 	 * selected maxshowdevs number of devices, go through the array and
840 	 * select any unselected devices.  If we're in "only" mode, we
841 	 * obviously don't want to select anything other than what the user
842 	 * specifies.  If we're in "remove" mode, it probably isn't a good
843 	 * idea to go through and select any more devices, since we might
844 	 * end up selecting something that the user wants removed.  Through
845 	 * more complicated logic, we could actually figure this out, but
846 	 * that would probably require combining this loop with the various
847 	 * selections loops above.
848 	 */
849 	if ((select_mode == DS_SELECT_ADD) && (*num_selected < maxshowdevs)) {
850 		for (i = 0; i < *num_selections; i++)
851 			if ((*dev_select)[i].selected == 0) {
852 				(*dev_select)[i].selected = ++selection_number;
853 				(*num_selected)++;
854 			}
855 	}
856 
857 	/*
858 	 * Look at the number of devices that have been selected.  If it
859 	 * has changed, set the changed variable.  Otherwise, if we've
860 	 * made a backup of the selection list, compare it to the current
861 	 * selection list to see if the selected devices have changed.
862 	 */
863 	if ((changed == 0) && (old_num_selected != *num_selected))
864 		changed = 1;
865 	else if ((changed == 0) && (old_dev_select != NULL)) {
866 		/*
867 		 * Now we go through the selection list and we look at
868 		 * it three different ways.
869 		 */
870 		for (i = 0; (i < *num_selections) && (changed == 0) &&
871 		     (i < old_num_selections); i++) {
872 			/*
873 			 * If the device at index i in both the new and old
874 			 * selection arrays has the same device number and
875 			 * selection status, it hasn't changed.  We
876 			 * continue on to the next index.
877 			 */
878 			if (((*dev_select)[i].device_number ==
879 			     old_dev_select[i].device_number)
880 			 && ((*dev_select)[i].selected ==
881 			     old_dev_select[i].selected))
882 				continue;
883 
884 			/*
885 			 * Now, if we're still going through the if
886 			 * statement, the above test wasn't true.  So we
887 			 * check here to see if the device at index i in
888 			 * the current array is the same as the device at
889 			 * index i in the old array.  If it is, that means
890 			 * that its selection number has changed.  Set
891 			 * changed to 1 and exit the loop.
892 			 */
893 			else if ((*dev_select)[i].device_number ==
894 			          old_dev_select[i].device_number) {
895 				changed = 1;
896 				break;
897 			}
898 			/*
899 			 * If we get here, then the device at index i in
900 			 * the current array isn't the same device as the
901 			 * device at index i in the old array.
902 			 */
903 			else {
904 				found = 0;
905 
906 				/*
907 				 * Search through the old selection array
908 				 * looking for a device with the same
909 				 * device number as the device at index i
910 				 * in the current array.  If the selection
911 				 * status is the same, then we mark it as
912 				 * found.  If the selection status isn't
913 				 * the same, we break out of the loop.
914 				 * Since found isn't set, changed will be
915 				 * set to 1 below.
916 				 */
917 				for (j = 0; j < old_num_selections; j++) {
918 					if (((*dev_select)[i].device_number ==
919 					      old_dev_select[j].device_number)
920 					 && ((*dev_select)[i].selected ==
921 					      old_dev_select[j].selected)){
922 						found = 1;
923 						break;
924 					}
925 					else if ((*dev_select)[i].device_number
926 					    == old_dev_select[j].device_number)
927 						break;
928 				}
929 				if (found == 0)
930 					changed = 1;
931 			}
932 		}
933 	}
934 	if (old_dev_select != NULL)
935 		free(old_dev_select);
936 
937 	return(changed);
938 }
939 
940 /*
941  * Comparison routine for qsort() above.  Note that the comparison here is
942  * backwards -- generally, it should return a value to indicate whether
943  * arg1 is <, =, or > arg2.  Instead, it returns the opposite.  The reason
944  * it returns the opposite is so that the selection array will be sorted in
945  * order of decreasing performance.  We sort on two parameters.  The first
946  * sort key is whether or not one or the other of the devices in question
947  * has been selected.  If one of them has, and the other one has not, the
948  * selected device is automatically more important than the unselected
949  * device.  If neither device is selected, we judge the devices based upon
950  * performance.
951  */
952 static int
953 compare_select(const void *arg1, const void *arg2)
954 {
955 	if ((((const struct device_selection *)arg1)->selected)
956 	 && (((const struct device_selection *)arg2)->selected == 0))
957 		return(-1);
958 	else if ((((const struct device_selection *)arg1)->selected == 0)
959 	      && (((const struct device_selection *)arg2)->selected))
960 		return(1);
961 	else if (((const struct device_selection *)arg2)->bytes <
962 	         ((const struct device_selection *)arg1)->bytes)
963 		return(-1);
964 	else if (((const struct device_selection *)arg2)->bytes >
965 		 ((const struct device_selection *)arg1)->bytes)
966 		return(1);
967 	else
968 		return(0);
969 }
970 
971 /*
972  * Take a string with the general format "arg1,arg2,arg3", and build a
973  * device matching expression from it.
974  */
975 int
976 devstat_buildmatch(char *match_str, struct devstat_match **matches,
977 		   int *num_matches)
978 {
979 	char *tstr[5];
980 	char **tempstr;
981 	int num_args;
982 	register int i, j;
983 	const char *func_name = "devstat_buildmatch";
984 
985 	/* We can't do much without a string to parse */
986 	if (match_str == NULL) {
987 		snprintf(devstat_errbuf, sizeof(devstat_errbuf),
988 			 "%s: no match expression", func_name);
989 		return(-1);
990 	}
991 
992 	/*
993 	 * Break the (comma delimited) input string out into separate strings.
994 	 */
995 	for (tempstr = tstr, num_args  = 0;
996 	     (*tempstr = strsep(&match_str, ",")) != NULL && (num_args < 5);
997 	     num_args++)
998 		if (**tempstr != '\0')
999 			if (++tempstr >= &tstr[5])
1000 				break;
1001 
1002 	/* The user gave us too many type arguments */
1003 	if (num_args > 3) {
1004 		snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1005 			 "%s: too many type arguments", func_name);
1006 		return(-1);
1007 	}
1008 
1009 	/*
1010 	 * Since you can't realloc a pointer that hasn't been malloced
1011 	 * first, we malloc first and then realloc.
1012 	 */
1013 	if (*num_matches == 0)
1014 		*matches = (struct devstat_match *)malloc(
1015 			   sizeof(struct devstat_match));
1016 	else
1017 		*matches = (struct devstat_match *)realloc(*matches,
1018 			  sizeof(struct devstat_match) * (*num_matches + 1));
1019 
1020 	/* Make sure the current entry is clear */
1021 	bzero(&matches[0][*num_matches], sizeof(struct devstat_match));
1022 
1023 	/*
1024 	 * Step through the arguments the user gave us and build a device
1025 	 * matching expression from them.
1026 	 */
1027 	for (i = 0; i < num_args; i++) {
1028 		char *tempstr2, *tempstr3;
1029 
1030 		/*
1031 		 * Get rid of leading white space.
1032 		 */
1033 		tempstr2 = tstr[i];
1034 		while (isspace(*tempstr2) && (*tempstr2 != '\0'))
1035 			tempstr2++;
1036 
1037 		/*
1038 		 * Get rid of trailing white space.
1039 		 */
1040 		tempstr3 = &tempstr2[strlen(tempstr2) - 1];
1041 
1042 		while ((*tempstr3 != '\0') && (tempstr3 > tempstr2)
1043 		    && (isspace(*tempstr3))) {
1044 			*tempstr3 = '\0';
1045 			tempstr3--;
1046 		}
1047 
1048 		/*
1049 		 * Go through the match table comparing the user's
1050 		 * arguments to known device types, interfaces, etc.
1051 		 */
1052 		for (j = 0; match_table[j].match_str != NULL; j++) {
1053 			/*
1054 			 * We do case-insensitive matching, in case someone
1055 			 * wants to enter "SCSI" instead of "scsi" or
1056 			 * something like that.  Only compare as many
1057 			 * characters as are in the string in the match
1058 			 * table.  This should help if someone tries to use
1059 			 * a super-long match expression.
1060 			 */
1061 			if (strncasecmp(tempstr2, match_table[j].match_str,
1062 			    strlen(match_table[j].match_str)) == 0) {
1063 				/*
1064 				 * Make sure the user hasn't specified two
1065 				 * items of the same type, like "da" and
1066 				 * "cd".  One device cannot be both.
1067 				 */
1068 				if (((*matches)[*num_matches].match_fields &
1069 				    match_table[j].match_field) != 0) {
1070 					snprintf(devstat_errbuf,
1071 						 sizeof(devstat_errbuf),
1072 						 "%s: cannot have more than "
1073 						 "one match item in a single "
1074 						 "category", func_name);
1075 					return(-1);
1076 				}
1077 				/*
1078 				 * If we've gotten this far, we have a
1079 				 * winner.  Set the appropriate fields in
1080 				 * the match entry.
1081 				 */
1082 				(*matches)[*num_matches].match_fields |=
1083 					match_table[j].match_field;
1084 				(*matches)[*num_matches].device_type |=
1085 					match_table[j].type;
1086 				(*matches)[*num_matches].num_match_categories++;
1087 				break;
1088 			}
1089 		}
1090 		/*
1091 		 * We should have found a match in the above for loop.  If
1092 		 * not, that means the user entered an invalid device type
1093 		 * or interface.
1094 		 */
1095 		if ((*matches)[*num_matches].num_match_categories != (i + 1)) {
1096 			snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1097 				 "%s: unknown match item \"%s\"", func_name,
1098 				 tstr[i]);
1099 			return(-1);
1100 		}
1101 	}
1102 
1103 	(*num_matches)++;
1104 
1105 	return(0);
1106 }
1107 
1108 /*
1109  * Compute a number of device statistics.  Only one field is mandatory, and
1110  * that is "current".  Everything else is optional.  The caller passes in
1111  * pointers to variables to hold the various statistics he desires.  If he
1112  * doesn't want a particular staistic, he should pass in a NULL pointer.
1113  * Return values:
1114  * 0   -- success
1115  * -1  -- failure
1116  */
1117 int
1118 compute_stats(struct devstat *current, struct devstat *previous,
1119 	      long double etime, u_int64_t *total_bytes,
1120 	      u_int64_t *total_transfers, u_int64_t *total_blocks,
1121 	      long double *kb_per_transfer, long double *transfers_per_second,
1122 	      long double *mb_per_second, long double *blocks_per_second,
1123 	      long double *ms_per_transaction)
1124 {
1125 	return(devstat_compute_statistics(current, previous, etime,
1126 	       total_bytes ? DSM_TOTAL_BYTES : DSM_SKIP,
1127 	       total_bytes,
1128 	       total_transfers ? DSM_TOTAL_TRANSFERS : DSM_SKIP,
1129 	       total_transfers,
1130 	       total_blocks ? DSM_TOTAL_BLOCKS : DSM_SKIP,
1131 	       total_blocks,
1132 	       kb_per_transfer ? DSM_KB_PER_TRANSFER : DSM_SKIP,
1133 	       kb_per_transfer,
1134 	       transfers_per_second ? DSM_TRANSFERS_PER_SECOND : DSM_SKIP,
1135 	       transfers_per_second,
1136 	       mb_per_second ? DSM_MB_PER_SECOND : DSM_SKIP,
1137 	       mb_per_second,
1138 	       blocks_per_second ? DSM_BLOCKS_PER_SECOND : DSM_SKIP,
1139 	       blocks_per_second,
1140 	       ms_per_transaction ? DSM_MS_PER_TRANSACTION : DSM_SKIP,
1141 	       ms_per_transaction,
1142 	       DSM_NONE));
1143 }
1144 
1145 long double
1146 devstat_compute_etime(struct timeval cur_time, struct timeval prev_time)
1147 {
1148 	struct timeval busy_time;
1149 	u_int64_t busy_usec;
1150 	long double etime;
1151 
1152 	timersub(&cur_time, &prev_time, &busy_time);
1153 
1154         busy_usec = busy_time.tv_sec;
1155         busy_usec *= 1000000;
1156         busy_usec += busy_time.tv_usec;
1157         etime = busy_usec;
1158         etime /= 1000000;
1159 
1160 	return(etime);
1161 }
1162 
1163 int
1164 devstat_compute_statistics(struct devstat *current, struct devstat *previous,
1165 			   long double etime, ...)
1166 {
1167 	const char *func_name = "devstat_compute_statistics";
1168 	u_int64_t totalbytes, totalbytesread, totalbyteswrite;
1169 	u_int64_t totaltransfers, totaltransfersread, totaltransferswrite;
1170 	u_int64_t totaltransfersother, totalblocks, totalblocksread;
1171 	u_int64_t totalblockswrite;
1172 	va_list ap;
1173 	devstat_metric metric;
1174 	u_int64_t *destu64;
1175 	long double *destld;
1176 	int retval;
1177 
1178 	retval = 0;
1179 
1180 	/*
1181 	 * current is the only mandatory field.
1182 	 */
1183 	if (current == NULL) {
1184 		snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1185 			 "%s: current stats structure was NULL", func_name);
1186 		return(-1);
1187 	}
1188 
1189 	totalbytesread = current->bytes_read -
1190 			 ((previous) ? previous->bytes_read : 0);
1191 	totalbyteswrite = current->bytes_written -
1192 			    ((previous) ? previous->bytes_written : 0);
1193 
1194 	totalbytes = totalbytesread + totalbyteswrite;
1195 
1196 	totaltransfersread = current->num_reads -
1197 			     ((previous) ? previous->num_reads : 0);
1198 
1199 	totaltransferswrite = current->num_writes -
1200 			      ((previous) ? previous->num_writes : 0);
1201 
1202 	totaltransfersother = current->num_other -
1203 			      ((previous) ? previous->num_other : 0);
1204 
1205 	totaltransfers = totaltransfersread + totaltransferswrite +
1206 			 totaltransfersother;
1207 
1208 	totalblocks = totalbytes;
1209 	totalblocksread = totalbytesread;
1210 	totalblockswrite = totalbyteswrite;
1211 
1212 	if (current->block_size > 0) {
1213 		totalblocks /= current->block_size;
1214 		totalblocksread /= current->block_size;
1215 		totalblockswrite /= current->block_size;
1216 	} else {
1217 		totalblocks /= 512;
1218 		totalblocksread /= 512;
1219 		totalblockswrite /= 512;
1220 	}
1221 
1222 	va_start(ap, etime);
1223 
1224 	while ((metric = (devstat_metric)va_arg(ap, devstat_metric)) != 0) {
1225 
1226 		if (metric == DSM_NONE)
1227 			break;
1228 
1229 		if (metric >= DSM_MAX) {
1230 			snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1231 				 "%s: metric %d is out of range", func_name,
1232 				 metric);
1233 			retval = -1;
1234 			goto bailout;
1235 		}
1236 
1237 		switch (devstat_arg_list[metric].argtype) {
1238 		case DEVSTAT_ARG_UINT64:
1239 			destu64 = (u_int64_t *)va_arg(ap, u_int64_t *);
1240 			break;
1241 		case DEVSTAT_ARG_LD:
1242 			destld = (long double *)va_arg(ap, long double *);
1243 			break;
1244 		case DEVSTAT_ARG_SKIP:
1245 			destld = (long double *)va_arg(ap, long double *);
1246 			break;
1247 		default:
1248 			retval = -1;
1249 			goto bailout;
1250 			break; /* NOTREACHED */
1251 		}
1252 
1253 		if (devstat_arg_list[metric].argtype == DEVSTAT_ARG_SKIP)
1254 			continue;
1255 
1256 		switch (metric) {
1257 		case DSM_TOTAL_BYTES:
1258 			*destu64 = totalbytes;
1259 			break;
1260 		case DSM_TOTAL_BYTES_READ:
1261 			*destu64 = totalbytesread;
1262 			break;
1263 		case DSM_TOTAL_BYTES_WRITE:
1264 			*destu64 = totalbyteswrite;
1265 			break;
1266 		case DSM_TOTAL_TRANSFERS:
1267 			*destu64 = totaltransfers;
1268 			break;
1269 		case DSM_TOTAL_TRANSFERS_READ:
1270 			*destu64 = totaltransfersread;
1271 			break;
1272 		case DSM_TOTAL_TRANSFERS_WRITE:
1273 			*destu64 = totaltransferswrite;
1274 			break;
1275 		case DSM_TOTAL_TRANSFERS_OTHER:
1276 			*destu64 = totaltransfersother;
1277 			break;
1278 		case DSM_TOTAL_BLOCKS:
1279 			*destu64 = totalblocks;
1280 			break;
1281 		case DSM_TOTAL_BLOCKS_READ:
1282 			*destu64 = totalblocksread;
1283 			break;
1284 		case DSM_TOTAL_BLOCKS_WRITE:
1285 			*destu64 = totalblockswrite;
1286 			break;
1287 		case DSM_KB_PER_TRANSFER:
1288 			*destld = totalbytes;
1289 			*destld /= 1024;
1290 			if (totaltransfers > 0)
1291 				*destld /= totaltransfers;
1292 			else
1293 				*destld = 0.0;
1294 			break;
1295 		case DSM_KB_PER_TRANSFER_READ:
1296 			*destld = totalbytesread;
1297 			*destld /= 1024;
1298 			if (totaltransfersread > 0)
1299 				*destld /= totaltransfersread;
1300 			else
1301 				*destld = 0.0;
1302 			break;
1303 		case DSM_KB_PER_TRANSFER_WRITE:
1304 			*destld = totalbyteswrite;
1305 			*destld /= 1024;
1306 			if (totaltransferswrite > 0)
1307 				*destld /= totaltransferswrite;
1308 			else
1309 				*destld = 0.0;
1310 			break;
1311 		case DSM_TRANSFERS_PER_SECOND:
1312 			if (etime > 0.0) {
1313 				*destld = totaltransfers;
1314 				*destld /= etime;
1315 			} else
1316 				*destld = 0.0;
1317 			break;
1318 		case DSM_TRANSFERS_PER_SECOND_READ:
1319 			if (etime > 0.0) {
1320 				*destld = totaltransfersread;
1321 				*destld /= etime;
1322 			} else
1323 				*destld = 0.0;
1324 			break;
1325 		case DSM_TRANSFERS_PER_SECOND_WRITE:
1326 			if (etime > 0.0) {
1327 				*destld = totaltransferswrite;
1328 				*destld /= etime;
1329 			} else
1330 				*destld = 0.0;
1331 			break;
1332 		case DSM_TRANSFERS_PER_SECOND_OTHER:
1333 			if (etime > 0.0) {
1334 				*destld = totaltransfersother;
1335 				*destld /= etime;
1336 			} else
1337 				*destld = 0.0;
1338 			break;
1339 		case DSM_MB_PER_SECOND:
1340 			*destld = totalbytes;
1341 			*destld /= 1024 * 1024;
1342 			if (etime > 0.0)
1343 				*destld /= etime;
1344 			else
1345 				*destld = 0.0;
1346 			break;
1347 		case DSM_MB_PER_SECOND_READ:
1348 			*destld = totalbytesread;
1349 			*destld /= 1024 * 1024;
1350 			if (etime > 0.0)
1351 				*destld /= etime;
1352 			else
1353 				*destld = 0.0;
1354 			break;
1355 		case DSM_MB_PER_SECOND_WRITE:
1356 			*destld = totalbyteswrite;
1357 			*destld /= 1024 * 1024;
1358 			if (etime > 0.0)
1359 				*destld /= etime;
1360 			else
1361 				*destld = 0.0;
1362 			break;
1363 		case DSM_BLOCKS_PER_SECOND:
1364 			*destld = totalblocks;
1365 			if (etime > 0.0)
1366 				*destld /= etime;
1367 			else
1368 				*destld = 0.0;
1369 			break;
1370 		case DSM_BLOCKS_PER_SECOND_READ:
1371 			*destld = totalblocksread;
1372 			if (etime > 0.0)
1373 				*destld /= etime;
1374 			else
1375 				*destld = 0.0;
1376 			break;
1377 		case DSM_BLOCKS_PER_SECOND_WRITE:
1378 			*destld = totalblockswrite;
1379 			if (etime > 0.0)
1380 				*destld /= etime;
1381 			else
1382 				*destld = 0.0;
1383 			break;
1384 		/*
1385 		 * This calculation is somewhat bogus.  It simply divides
1386 		 * the elapsed time by the total number of transactions
1387 		 * completed.  While that does give the caller a good
1388 		 * picture of the average rate of transaction completion,
1389 		 * it doesn't necessarily give the caller a good view of
1390 		 * how long transactions took to complete on average.
1391 		 * Those two numbers will be different for a device that
1392 		 * can handle more than one transaction at a time.  e.g.
1393 		 * SCSI disks doing tagged queueing.
1394 		 *
1395 		 * The only way to accurately determine the real average
1396 		 * time per transaction would be to compute and store the
1397 		 * time on a per-transaction basis.  That currently isn't
1398 		 * done in the kernel, and would only be desireable if it
1399 		 * could be implemented in a somewhat non-intrusive and high
1400 		 * performance way.
1401 		 */
1402 		case DSM_MS_PER_TRANSACTION:
1403 			if (totaltransfers > 0) {
1404 				*destld = etime;
1405 				*destld /= totaltransfers;
1406 				*destld *= 1000;
1407 			} else
1408 				*destld = 0.0;
1409 			break;
1410 		/*
1411 		 * As above, these next two really only give the average
1412 		 * rate of completion for read and write transactions, not
1413 		 * the average time the transaction took to complete.
1414 		 */
1415 		case DSM_MS_PER_TRANSACTION_READ:
1416 			if (totaltransfersread > 0) {
1417 				*destld = etime;
1418 				*destld /= totaltransfersread;
1419 				*destld *= 1000;
1420 			} else
1421 				*destld = 0.0;
1422 			break;
1423 		case DSM_MS_PER_TRANSACTION_WRITE:
1424 			if (totaltransferswrite > 0) {
1425 				*destld = etime;
1426 				*destld /= totaltransferswrite;
1427 				*destld *= 1000;
1428 			} else
1429 				*destld = 0.0;
1430 			break;
1431 		default:
1432 			/*
1433 			 * This shouldn't happen, since we should have
1434 			 * caught any out of range metrics at the top of
1435 			 * the loop.
1436 			 */
1437 			snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1438 				 "%s: unknown metric %d", func_name, metric);
1439 			retval = -1;
1440 			goto bailout;
1441 			break; /* NOTREACHED */
1442 		}
1443 	}
1444 
1445 bailout:
1446 
1447 	va_end(ap);
1448 	return(retval);
1449 }
1450 
1451 static int
1452 readkmem(kvm_t *kd, unsigned long addr, void *buf, size_t nbytes)
1453 {
1454 	const char *func_name = "readkmem";
1455 
1456 	if (kvm_read(kd, addr, buf, nbytes) == -1) {
1457 		snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1458 			 "%s: error reading value (kvm_read): %s", func_name,
1459 			 kvm_geterr(kd));
1460 		return(-1);
1461 	}
1462 	return(0);
1463 }
1464 
1465 static int
1466 readkmem_nl(kvm_t *kd, const char *name, void *buf, size_t nbytes)
1467 {
1468 	const char *func_name = "readkmem_nl";
1469 	struct nlist nl[2];
1470 
1471 	(const char *)nl[0].n_name = name;
1472 	nl[1].n_name = NULL;
1473 
1474 	if (kvm_nlist(kd, nl) == -1) {
1475 		snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1476 			 "%s: error getting name list (kvm_nlist): %s",
1477 			 func_name, kvm_geterr(kd));
1478 		return(-1);
1479 	}
1480 	return(readkmem(kd, nl[0].n_value, buf, nbytes));
1481 }
1482 
1483 /*
1484  * This duplicates the functionality of the kernel sysctl handler for poking
1485  * through crash dumps.
1486  */
1487 static char *
1488 get_devstat_kvm(kvm_t *kd)
1489 {
1490 	int error, i, wp;
1491 	long gen;
1492 	struct devstat *nds;
1493 	struct devstat ds;
1494 	struct devstatlist dhead;
1495 	int num_devs;
1496 	char *rv = NULL;
1497 	const char *func_name = "get_devstat_kvm";
1498 
1499 	if ((num_devs = getnumdevs()) <= 0)
1500 		return(NULL);
1501 	error = 0;
1502 	if (KREADNL(kd, X_DEVICE_STATQ, dhead) == -1)
1503 		return(NULL);
1504 
1505 	nds = STAILQ_FIRST(&dhead);
1506 
1507 	if ((rv = malloc(sizeof(gen))) == NULL) {
1508 		snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1509 			 "%s: out of memory (initial malloc failed)",
1510 			 func_name);
1511 		return(NULL);
1512 	}
1513 	gen = getgeneration();
1514 	memcpy(rv, &gen, sizeof(gen));
1515 	wp = sizeof(gen);
1516 	/*
1517 	 * Now push out all the devices.
1518 	 */
1519 	for (i = 0; (nds != NULL) && (i < num_devs);
1520 	     nds = STAILQ_NEXT(nds, dev_links), i++) {
1521 		if (readkmem(kd, (long)nds, &ds, sizeof(ds)) == -1) {
1522 			free(rv);
1523 			return(NULL);
1524 		}
1525 		nds = &ds;
1526 		rv = (char *)reallocf(rv, sizeof(gen) +
1527 				      sizeof(ds) * (i + 1));
1528 		if (rv == NULL) {
1529 			snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1530 				 "%s: out of memory (malloc failed)",
1531 				 func_name);
1532 			return(NULL);
1533 		}
1534 		memcpy(rv + wp, &ds, sizeof(ds));
1535 		wp += sizeof(ds);
1536 	}
1537 	return(rv);
1538 }
1539 
1540 /*
1541  * Compatability functions for libdevstat 2. These are deprecated and may
1542  * eventually be removed.
1543  */
1544 int
1545 getnumdevs(void)
1546 {
1547 	return(devstat_getnumdevs(NULL));
1548 }
1549 
1550 long
1551 getgeneration(void)
1552 {
1553 	return(devstat_getgeneration(NULL));
1554 }
1555 
1556 int
1557 getversion(void)
1558 {
1559 	return(devstat_getversion(NULL));
1560 }
1561 
1562 int
1563 checkversion(void)
1564 {
1565 	return(devstat_checkversion(NULL));
1566 }
1567 
1568 int
1569 getdevs(struct statinfo *stats)
1570 {
1571 	return(devstat_getdevs(NULL, stats));
1572 }
1573 
1574 int
1575 selectdevs(struct device_selection **dev_select, int *num_selected,
1576 	   int *num_selections, long *select_generation,
1577 	   long current_generation, struct devstat *devices, int numdevs,
1578 	   struct devstat_match *matches, int num_matches,
1579 	   char **dev_selections, int num_dev_selections,
1580 	   devstat_select_mode select_mode, int maxshowdevs,
1581 	   int perf_select)
1582 {
1583 
1584 	return(devstat_selectdevs(dev_select, num_selected, num_selections,
1585 	       select_generation, current_generation, devices, numdevs,
1586 	       matches, num_matches, dev_selections, num_dev_selections,
1587 	       select_mode, maxshowdevs, perf_select));
1588 }
1589 
1590 int
1591 buildmatch(char *match_str, struct devstat_match **matches,
1592 	   int *num_matches)
1593 {
1594 	return(devstat_buildmatch(match_str, matches, num_matches));
1595 }
1596 
1597 long double
1598 compute_etime(struct timeval cur_time, struct timeval prev_time)
1599 {
1600 	return(devstat_compute_etime(cur_time, prev_time));
1601 }
1602