lib/libdevstat/devstat.c

   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  * $FreeBSD: src/lib/libdevstat/devstat.c,v 1.6 1999/08/28 00:04:26 peter Exp $
  29  * $DragonFly: src/lib/libdevstat/devstat.c,v 1.5 2005/01/08 19:19:26 joerg Exp $
  30  */
  31
  32 #include <sys/types.h>
  33 #include <sys/sysctl.h>
  34 #include <sys/errno.h>
  35
  36 #include <ctype.h>
  37 #include <err.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 #include "devstat.h"
  43
  44 char devstat_errbuf[DEVSTAT_ERRBUF_SIZE];
  45
  46 /*
  47  * Table to match descriptive strings with device types.  These are in
  48  * order from most common to least common to speed search time.
  49  */
  50 struct devstat_match_table match_table[] = {
  51         {"da",          DEVSTAT_TYPE_DIRECT,    DEVSTAT_MATCH_TYPE},
  52         {"nvme",        DEVSTAT_TYPE_DIRECT,    DEVSTAT_MATCH_TYPE},
  53         {"xa",          DEVSTAT_TYPE_DIRECT,    DEVSTAT_MATCH_TYPE},
  54         {"cd",          DEVSTAT_TYPE_CDROM,     DEVSTAT_MATCH_TYPE},
  55         {"scsi",        DEVSTAT_TYPE_IF_SCSI,   DEVSTAT_MATCH_IF},
  56         {"ide",         DEVSTAT_TYPE_IF_IDE,    DEVSTAT_MATCH_IF},
  57         {"other",       DEVSTAT_TYPE_IF_OTHER,  DEVSTAT_MATCH_IF},
  58         {"worm",        DEVSTAT_TYPE_WORM,      DEVSTAT_MATCH_TYPE},
  59         {"sa",          DEVSTAT_TYPE_SEQUENTIAL,DEVSTAT_MATCH_TYPE},
  60         {"pass",        DEVSTAT_TYPE_PASS,      DEVSTAT_MATCH_PASS},
  61         {"optical",     DEVSTAT_TYPE_OPTICAL,   DEVSTAT_MATCH_TYPE},
  62         {"array",       DEVSTAT_TYPE_STORARRAY, DEVSTAT_MATCH_TYPE},
  63         {"changer",     DEVSTAT_TYPE_CHANGER,   DEVSTAT_MATCH_TYPE},
  64         {"scanner",     DEVSTAT_TYPE_SCANNER,   DEVSTAT_MATCH_TYPE},
  65         {"printer",     DEVSTAT_TYPE_PRINTER,   DEVSTAT_MATCH_TYPE},
  66         {"floppy",      DEVSTAT_TYPE_FLOPPY,    DEVSTAT_MATCH_TYPE},
  67         {"proc",        DEVSTAT_TYPE_PROCESSOR, DEVSTAT_MATCH_TYPE},
  68         {"comm",        DEVSTAT_TYPE_COMM,      DEVSTAT_MATCH_TYPE},
  69         {"enclosure",   DEVSTAT_TYPE_ENCLOSURE, DEVSTAT_MATCH_TYPE},
  70         {NULL,          0,                      0}
  71 };
  72
  73 /*
  74  * Local function declarations.
  75  */
  76 static int compare_select(const void *arg1, const void *arg2);
  77
  78 int
  79 getnumdevs(void)
  80 {
  81         size_t numdevsize;
  82         int numdevs;
  83         const char *func_name = "getnumdevs";
  84
  85         numdevsize = sizeof(int);
  86
  87         /*
  88          * Find out how many devices we have in the system.
  89          */
  90         if (sysctlbyname("kern.devstat.numdevs", &numdevs,
  91                          &numdevsize, NULL, 0) == -1) {
  92                 sprintf(devstat_errbuf, "%s: error getting number of devices\n"
  93                         "%s: %s", func_name, func_name, strerror(errno));
  94                 return(-1);
  95         } else
  96                 return(numdevs);
  97 }
  98
  99 /*
 100  * This is an easy way to get the generation number, but the generation is
 101  * supplied in a more atmoic manner by the kern.devstat.all sysctl.
 102  * Because this generation sysctl is separate from the statistics sysctl,
 103  * the device list and the generation could change between the time that
 104  * this function is called and the device list is retreived.
 105  */
 106 long
 107 getgeneration(void)
 108 {
 109         size_t gensize;
 110         long generation;
 111         const char *func_name = "getgeneration";
 112
 113         gensize = sizeof(long);
 114
 115         /*
 116          * Get the current generation number.
 117          */
 118         if (sysctlbyname("kern.devstat.generation", &generation,
 119                          &gensize, NULL, 0) == -1) {
 120                 sprintf(devstat_errbuf,"%s: error getting devstat generation\n"
 121                         "%s: %s", func_name, func_name, strerror(errno));
 122                 return(-1);
 123         } else
 124                 return(generation);
 125 }
 126
 127 /*
 128  * Get the current devstat version.  The return value of this function
 129  * should be compared with DEVSTAT_VERSION, which is defined in
 130  * sys/devicestat.h.  This will enable userland programs to determine
 131  * whether they are out of sync with the kernel.
 132  */
 133 int
 134 getversion(void)
 135 {
 136         size_t versize;
 137         int version;
 138         const char *func_name = "getversion";
 139
 140         versize = sizeof(int);
 141
 142         /*
 143          * Get the current devstat version.
 144          */
 145         if (sysctlbyname("kern.devstat.version", &version, &versize,
 146                          NULL, 0) == -1) {
 147                 sprintf(devstat_errbuf, "%s: error getting devstat version\n"
 148                         "%s: %s", func_name, func_name, strerror(errno));
 149                 return(-1);
 150         } else
 151                 return(version);
 152 }
 153
 154 /*
 155  * Check the devstat version we know about against the devstat version the
 156  * kernel knows about.  If they don't match, print an error into the
 157  * devstat error buffer, and return -1.  If they match, return 0.
 158  */
 159 int
 160 checkversion(void)
 161 {
 162         int retval = 0;
 163         int errlen = 0;
 164         const char *func_name = "checkversion";
 165         int version;
 166
 167         version = getversion();
 168
 169         if (version != DEVSTAT_VERSION) {
 170                 int buflen = 0;
 171                 char tmpstr[256];
 172
 173                 /*
 174                  * This is really pretty silly, but basically the idea is
 175                  * that if getversion() returns an error (i.e. -1), then it
 176                  * has printed an error message in the buffer.  Therefore,
 177                  * we need to add a \n to the end of that message before we
 178                  * print our own message in the buffer.
 179                  */
 180                 if (version == -1) {
 181                         buflen = strlen(devstat_errbuf);
 182                         errlen = snprintf(tmpstr, sizeof(tmpstr), "\n");
 183                         strncat(devstat_errbuf, tmpstr,
 184                                 DEVSTAT_ERRBUF_SIZE - buflen - 1);
 185                         buflen += errlen;
 186                 }
 187
 188                 errlen = snprintf(tmpstr, sizeof(tmpstr),
 189                                   "%s: userland devstat version %d is not "
 190                                   "the same as the kernel\n%s: devstat "
 191                                   "version %d\n", func_name, DEVSTAT_VERSION,
 192                                   func_name, version);
 193
 194                 if (version == -1) {
 195                         strncat(devstat_errbuf, tmpstr,
 196                                 DEVSTAT_ERRBUF_SIZE - buflen - 1);
 197                         buflen += errlen;
 198                 } else {
 199                         strncpy(devstat_errbuf, tmpstr, DEVSTAT_ERRBUF_SIZE);
 200                         devstat_errbuf[DEVSTAT_ERRBUF_SIZE - 1] = '\0';
 201                 }
 202
 203                 if (version < DEVSTAT_VERSION)
 204                         snprintf(tmpstr, sizeof(tmpstr),
 205                                  "%s: libdevstat newer than kernel\n",
 206                                  func_name);
 207                 else
 208                         snprintf(tmpstr, sizeof(tmpstr),
 209                                  "%s: kernel newer than libdevstat\n",
 210                                  func_name);
 211
 212                 strncat(devstat_errbuf, tmpstr,
 213                         DEVSTAT_ERRBUF_SIZE - buflen - 1);
 214
 215                 retval = -1;
 216         }
 217
 218         return(retval);
 219 }
 220
 221 /*
 222  * Get the current list of devices and statistics, and the current
 223  * generation number.
 224  *
 225  * Return values:
 226  * -1  -- error
 227  *  0  -- device list is unchanged
 228  *  1  -- device list has changed
 229  */
 230 int
 231 getdevs(struct statinfo *stats)
 232 {
 233         int error;
 234         size_t dssize;
 235         long oldgeneration;
 236         int retval = 0;
 237         struct devinfo *dinfo;
 238         const char *func_name = "getdevs";
 239
 240         dinfo = stats->dinfo;
 241
 242         if (dinfo == NULL) {
 243                 sprintf(devstat_errbuf, "%s: stats->dinfo was NULL", func_name);
 244                 return(-1);
 245         }
 246
 247         oldgeneration = dinfo->generation;
 248
 249         /*
 250          * If this is our first time through, mem_ptr will be null.
 251          */
 252         if (dinfo->mem_ptr == NULL) {
 253                 /*
 254                  * Get the number of devices.  If it's negative, it's an
 255                  * error.  Don't bother setting the error string, since
 256                  * getnumdevs() has already done that for us.
 257                  */
 258                 if ((dinfo->numdevs = getnumdevs()) < 0)
 259                         return(-1);
 260
 261                 /*
 262                  * The kern.devstat.all sysctl returns the current generation
 263                  * number, as well as all the devices.  So we need four
 264                  * bytes more.
 265                  */
 266                 dssize =(dinfo->numdevs * sizeof(struct devstat)) +sizeof(long);
 267                 dinfo->mem_ptr = (u_int8_t *)malloc(dssize);
 268         } else
 269                 dssize =(dinfo->numdevs * sizeof(struct devstat)) +sizeof(long);
 270
 271         /* Get the current time when we get the stats */
 272         gettimeofday(&stats->busy_time, NULL);
 273
 274         /*
 275          * Request all of the devices.  We only really allow for one
 276          * ENOMEM failure.  It would, of course, be possible to just go in
 277          * a loop and keep reallocing the device structure until we don't
 278          * get ENOMEM back.  I'm not sure it's worth it, though.  If
 279          * devices are being added to the system that quickly, maybe the
 280          * user can just wait until all devices are added.
 281          */
 282         if ((error = sysctlbyname("kern.devstat.all", dinfo->mem_ptr,
 283              &dssize, NULL, 0)) == -1) {
 284                 /*
 285                  * If we get ENOMEM back, that means that there are
 286                  * more devices now, so we need to allocate more
 287                  * space for the device array.
 288                  */
 289                 if (errno == ENOMEM) {
 290                         /*
 291                          * No need to set the error string here, getnumdevs()
 292                          * will do that if it fails.
 293                          */
 294                         if ((dinfo->numdevs = getnumdevs()) < 0)
 295                                 return(-1);
 296
 297                         dssize = (dinfo->numdevs * sizeof(struct devstat)) +
 298                                 sizeof(long);
 299                         dinfo->mem_ptr = (u_int8_t *)realloc(dinfo->mem_ptr,
 300                                                              dssize);
 301                         if ((error = sysctlbyname("kern.devstat.all",
 302                             dinfo->mem_ptr, &dssize, NULL, 0)) == -1) {
 303                                 sprintf(devstat_errbuf,
 304                                         "%s: error getting device stats\n"
 305                                         "%s: %s", func_name, func_name,
 306                                         strerror(errno));
 307                                 return(-1);
 308                         }
 309                 } else {
 310                         sprintf(devstat_errbuf,
 311                                 "%s: error getting device stats\n"
 312                                 "%s: %s", func_name, func_name,
 313                                 strerror(errno));
 314                         return(-1);
 315                 }
 316         }
 317
 318         /*
 319          * The sysctl spits out the generation as the first four bytes,
 320          * then all of the device statistics structures.
 321          */
 322         dinfo->generation = *(long *)dinfo->mem_ptr;
 323
 324         /*
 325          * If the generation has changed, and if the current number of
 326          * devices is not the same as the number of devices recorded in the
 327          * devinfo structure, it is likely that the device list has shrunk.
 328          * The reason that it is likely that the device list has shrunk in
 329          * this case is that if the device list has grown, the sysctl above
 330          * will return an ENOMEM error, and we will reset the number of
 331          * devices and reallocate the device array.  If the second sysctl
 332          * fails, we will return an error and therefore never get to this
 333          * point.  If the device list has shrunk, the sysctl will not
 334          * return an error since we have more space allocated than is
 335          * necessary.  So, in the shrinkage case, we catch it here and
 336          * reallocate the array so that we don't use any more space than is
 337          * necessary.
 338          */
 339         if (oldgeneration != dinfo->generation) {
 340                 if (getnumdevs() != dinfo->numdevs) {
 341                         if ((dinfo->numdevs = getnumdevs()) < 0)
 342                                 return(-1);
 343                         dssize = (dinfo->numdevs * sizeof(struct devstat)) +
 344                                 sizeof(long);
 345                         dinfo->mem_ptr = (u_int8_t *)realloc(dinfo->mem_ptr,
 346                                                              dssize);
 347                 }
 348                 retval = 1;
 349         }
 350
 351         dinfo->devices = (struct devstat *)(dinfo->mem_ptr + sizeof(long));
 352
 353         return(retval);
 354 }
 355
 356 /*
 357  * selectdevs():
 358  *
 359  * Devices are selected/deselected based upon the following criteria:
 360  * - devices specified by the user on the command line
 361  * - devices matching any device type expressions given on the command line
 362  * - devices with the highest I/O, if 'top' mode is enabled
 363  * - the first n unselected devices in the device list, if maxshowdevs
 364  *   devices haven't already been selected and if the user has not
 365  *   specified any devices on the command line and if we're in "add" mode.
 366  *
 367  * Input parameters:
 368  * - device selection list (dev_select)
 369  * - current number of devices selected (num_selected)
 370  * - total number of devices in the selection list (num_selections)
 371  * - devstat generation as of the last time selectdevs() was called
 372  *   (select_generation)
 373  * - current devstat generation (current_generation)
 374  * - current list of devices and statistics (devices)
 375  * - number of devices in the current device list (numdevs)
 376  * - compiled version of the command line device type arguments (matches)
 377  *   - This is optional.  If the number of devices is 0, this will be ignored.
 378  *   - The matching code pays attention to the current selection mode.  So
 379  *     if you pass in a matching expression, it will be evaluated based
 380  *     upon the selection mode that is passed in.  See below for details.
 381  * - number of device type matching expressions (num_matches)
 382  *   - Set to 0 to disable the matching code.
 383  * - list of devices specified on the command line by the user (dev_selections)
 384  * - number of devices selected on the command line by the user
 385  *   (num_dev_selections)
 386  * - Our selection mode.  There are four different selection modes:
 387  *      - add mode.  (DS_SELECT_ADD) Any devices matching devices explicitly
 388  *        selected by the user or devices matching a pattern given by the
 389  *        user will be selected in addition to devices that are already
 390  *        selected.  Additional devices will be selected, up to maxshowdevs
 391  *        number of devices.
 392  *      - only mode. (DS_SELECT_ONLY)  Only devices matching devices
 393  *        explicitly given by the user or devices matching a pattern
 394  *        given by the user will be selected.  No other devices will be
 395  *        selected.
 396  *      - addonly mode.  (DS_SELECT_ADDONLY)  This is similar to add and
 397  *        only.  Basically, this will not de-select any devices that are
 398  *        current selected, as only mode would, but it will also not
 399  *        gratuitously select up to maxshowdevs devices as add mode would.
 400  *      - remove mode.  (DS_SELECT_REMOVE)  Any devices matching devices
 401  *        explicitly selected by the user or devices matching a pattern
 402  *        given by the user will be de-selected.
 403  * - maximum number of devices we can select (maxshowdevs)
 404  * - flag indicating whether or not we're in 'top' mode (perf_select)
 405  *
 406  * Output data:
 407  * - the device selection list may be modified and passed back out
 408  * - the number of devices selected and the total number of items in the
 409  *   device selection list may be changed
 410  * - the selection generation may be changed to match the current generation
 411  *
 412  * Return values:
 413  * -1  -- error
 414  *  0  -- selected devices are unchanged
 415  *  1  -- selected devices changed
 416  */
 417 int
 418 selectdevs(struct device_selection **dev_select, int *num_selected,
 419            int *num_selections, long *select_generation,
 420            long current_generation, struct devstat *devices, int numdevs,
 421            struct devstat_match *matches, int num_matches,
 422            char **dev_selections, int num_dev_selections,
 423            devstat_select_mode select_mode, int maxshowdevs, int perf_select)
 424 {
 425         int i, j, k;
 426         int init_selections = 0, init_selected_var = 0;
 427         struct device_selection *old_dev_select = NULL;
 428         int old_num_selections = 0, old_num_selected;
 429         int selection_number = 0;
 430         int changed = 0, found = 0;
 431
 432         if ((dev_select == NULL) || (devices == NULL) || (numdevs <= 0))
 433                 return(-1);
 434
 435         /*
 436          * We always want to make sure that we have as many dev_select
 437          * entries as there are devices.
 438          */
 439         /*
 440          * In this case, we haven't selected devices before.
 441          */
 442         if (*dev_select == NULL) {
 443                 *dev_select = (struct device_selection *)malloc(numdevs *
 444                         sizeof(struct device_selection));
 445                 *select_generation = current_generation;
 446                 init_selections = 1;
 447                 changed = 1;
 448         /*
 449          * In this case, we have selected devices before, but the device
 450          * list has changed since we last selected devices, so we need to
 451          * either enlarge or reduce the size of the device selection list.
 452          */
 453         } else if (*num_selections != numdevs) {
 454                 *dev_select = (struct device_selection *)realloc(*dev_select,
 455                         numdevs * sizeof(struct device_selection));
 456                 *select_generation = current_generation;
 457                 init_selections = 1;
 458         /*
 459          * In this case, we've selected devices before, and the selection
 460          * list is the same size as it was the last time, but the device
 461          * list has changed.
 462          */
 463         } else if (*select_generation < current_generation) {
 464                 *select_generation = current_generation;
 465                 init_selections = 1;
 466         }
 467
 468         /*
 469          * If we're in "only" mode, we want to clear out the selected
 470          * variable since we're going to select exactly what the user wants
 471          * this time through.
 472          */
 473         if (select_mode == DS_SELECT_ONLY)
 474                 init_selected_var = 1;
 475
 476         /*
 477          * In all cases, we want to back up the number of selected devices.
 478          * It is a quick and accurate way to determine whether the selected
 479          * devices have changed.
 480          */
 481         old_num_selected = *num_selected;
 482
 483         /*
 484          * We want to make a backup of the current selection list if
 485          * the list of devices has changed, or if we're in performance
 486          * selection mode.  In both cases, we don't want to make a backup
 487          * if we already know for sure that the list will be different.
 488          * This is certainly the case if this is our first time through the
 489          * selection code.
 490          */
 491         if (((init_selected_var != 0) || (init_selections != 0)
 492          || (perf_select != 0)) && (changed == 0)){
 493                 old_dev_select = (struct device_selection *)malloc(
 494                     *num_selections * sizeof(struct device_selection));
 495                 old_num_selections = *num_selections;
 496                 bcopy(*dev_select, old_dev_select,
 497                     sizeof(struct device_selection) * *num_selections);
 498         }
 499
 500         if (init_selections != 0) {
 501                 bzero(*dev_select, sizeof(struct device_selection) * numdevs);
 502
 503                 for (i = 0; i < numdevs; i++) {
 504                         (*dev_select)[i].device_number =
 505                                 devices[i].device_number;
 506                         strncpy((*dev_select)[i].device_name,
 507                                 devices[i].device_name,
 508                                 DEVSTAT_NAME_LEN);
 509                         (*dev_select)[i].device_name[DEVSTAT_NAME_LEN - 1]='\0';
 510                         (*dev_select)[i].unit_number = devices[i].unit_number;
 511                         (*dev_select)[i].position = i;
 512                 }
 513                 *num_selections = numdevs;
 514         } else if (init_selected_var != 0) {
 515                 for (i = 0; i < numdevs; i++)
 516                         (*dev_select)[i].selected = 0;
 517         }
 518
 519         /* we haven't gotten around to selecting anything yet.. */
 520         if ((select_mode == DS_SELECT_ONLY) || (init_selections != 0)
 521          || (init_selected_var != 0))
 522                 *num_selected = 0;
 523
 524         /*
 525          * Look through any devices the user specified on the command line
 526          * and see if they match known devices.  If so, select them.
 527          */
 528         for (i = 0; (i < *num_selections) && (num_dev_selections > 0); i++) {
 529                 char tmpstr[80];
 530
 531                 snprintf(tmpstr, sizeof(tmpstr), "%s%d",
 532                         (*dev_select)[i].device_name,
 533                         (*dev_select)[i].unit_number);
 534                 for (j = 0; j < num_dev_selections; j++) {
 535                         if (strcmp(tmpstr, dev_selections[j]) == 0) {
 536                                 /*
 537                                  * Here we do different things based on the
 538                                  * mode we're in.  If we're in add or
 539                                  * addonly mode, we only select this device
 540                                  * if it hasn't already been selected.
 541                                  * Otherwise, we would be unnecessarily
 542                                  * changing the selection order and
 543                                  * incrementing the selection count.  If
 544                                  * we're in only mode, we unconditionally
 545                                  * select this device, since in only mode
 546                                  * any previous selections are erased and
 547                                  * manually specified devices are the first
 548                                  * ones to be selected.  If we're in remove
 549                                  * mode, we de-select the specified device and
 550                                  * decrement the selection count.
 551                                  */
 552                                 switch(select_mode) {
 553                                 case DS_SELECT_ADD:
 554                                 case DS_SELECT_ADDONLY:
 555                                         if ((*dev_select)[i].selected)
 556                                                 break;
 557                                         /* FALLTHROUGH */
 558                                 case DS_SELECT_ONLY:
 559                                         (*dev_select)[i].selected =
 560                                                 ++selection_number;
 561                                         (*num_selected)++;
 562                                         break;
 563                                 case DS_SELECT_REMOVE:
 564                                         (*dev_select)[i].selected = 0;
 565                                         (*num_selected)--;
 566                                         break;
 567                                 }
 568                                 break;
 569                         }
 570                 }
 571         }
 572
 573         /*
 574          * Go through the user's device type expressions and select devices
 575          * accordingly.  We only do this if the number of devices already
 576          * selected is less than the maximum number we can show.
 577          */
 578         for (i = 0; (i < num_matches) && (*num_selected < maxshowdevs); i++) {
 579                 /* We should probably indicate some error here */
 580                 if ((matches[i].match_fields == DEVSTAT_MATCH_NONE)
 581                  || (matches[i].num_match_categories <= 0))
 582                         continue;
 583
 584                 for (j = 0; j < numdevs; j++) {
 585                         int num_match_categories;
 586
 587                         num_match_categories = matches[i].num_match_categories;
 588
 589                         /*
 590                          * Determine whether or not the current device
 591                          * matches the given matching expression.  This if
 592                          * statement consists of three components:
 593                          *   - the device type check
 594                          *   - the device interface check
 595                          *   - the passthrough check
 596                          * If a the matching test is successful, it
 597                          * decrements the number of matching categories,
 598                          * and if we've reached the last element that
 599                          * needed to be matched, the if statement succeeds.
 600                          *
 601                          */
 602                         if ((((matches[i].match_fields & DEVSTAT_MATCH_TYPE)!=0)
 603                           && ((devices[j].device_type & DEVSTAT_TYPE_MASK) ==
 604                                 (matches[i].device_type & DEVSTAT_TYPE_MASK))
 605                           &&(((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
 606                            || (((devices[j].device_type &
 607                                 DEVSTAT_TYPE_PASS) == 0)))
 608                           && (--num_match_categories == 0))
 609                          || (((matches[i].match_fields & DEVSTAT_MATCH_IF) != 0)
 610                           && ((devices[j].device_type & DEVSTAT_TYPE_IF_MASK) ==
 611                                 (matches[i].device_type & DEVSTAT_TYPE_IF_MASK))
 612                           &&(((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
 613                            || (((devices[j].device_type &
 614                                 DEVSTAT_TYPE_PASS) == 0)))
 615                           && (--num_match_categories == 0))
 616                          || (((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
 617                           && ((devices[j].device_type & DEVSTAT_TYPE_PASS) != 0)
 618                           && (--num_match_categories == 0))) {
 619
 620                                 /*
 621                                  * This is probably a non-optimal solution
 622                                  * to the problem that the devices in the
 623                                  * device list will not be in the same
 624                                  * order as the devices in the selection
 625                                  * array.
 626                                  */
 627                                 for (k = 0; k < numdevs; k++) {
 628                                         if ((*dev_select)[k].position == j) {
 629                                                 found = 1;
 630                                                 break;
 631                                         }
 632                                 }
 633
 634                                 /*
 635                                  * There shouldn't be a case where a device
 636                                  * in the device list is not in the
 637                                  * selection list...but it could happen.
 638                                  */
 639                                 if (found != 1) {
 640                                         fprintf(stderr, "selectdevs: couldn't"
 641                                                 " find %s%d in selection "
 642                                                 "list\n",
 643                                                 devices[j].device_name,
 644                                                 devices[j].unit_number);
 645                                         break;
 646                                 }
 647
 648                                 /*
 649                                  * We do different things based upon the
 650                                  * mode we're in.  If we're in add or only
 651                                  * mode, we go ahead and select this device
 652                                  * if it hasn't already been selected.  If
 653                                  * it has already been selected, we leave
 654                                  * it alone so we don't mess up the
 655                                  * selection ordering.  Manually specified
 656                                  * devices have already been selected, and
 657                                  * they have higher priority than pattern
 658                                  * matched devices.  If we're in remove
 659                                  * mode, we de-select the given device and
 660                                  * decrement the selected count.
 661                                  */
 662                                 switch(select_mode) {
 663                                 case DS_SELECT_ADD:
 664                                 case DS_SELECT_ADDONLY:
 665                                 case DS_SELECT_ONLY:
 666                                         if ((*dev_select)[k].selected != 0)
 667                                                 break;
 668                                         (*dev_select)[k].selected =
 669                                                 ++selection_number;
 670                                         (*num_selected)++;
 671                                         break;
 672                                 case DS_SELECT_REMOVE:
 673                                         (*dev_select)[k].selected = 0;
 674                                         (*num_selected)--;
 675                                         break;
 676                                 }
 677                         }
 678                 }
 679         }
 680
 681         /*
 682          * Here we implement "top" mode.  Devices are sorted in the
 683          * selection array based on two criteria:  whether or not they are
 684          * selected (not selection number, just the fact that they are
 685          * selected!) and the number of bytes in the "bytes" field of the
 686          * selection structure.  The bytes field generally must be kept up
 687          * by the user.  In the future, it may be maintained by library
 688          * functions, but for now the user has to do the work.
 689          *
 690          * At first glance, it may seem wrong that we don't go through and
 691          * select every device in the case where the user hasn't specified
 692          * any devices or patterns.  In fact, though, it won't make any
 693          * difference in the device sorting.  In that particular case (i.e.
 694          * when we're in "add" or "only" mode, and the user hasn't
 695          * specified anything) the first time through no devices will be
 696          * selected, so the only criterion used to sort them will be their
 697          * performance.  The second time through, and every time thereafter,
 698          * all devices will be selected, so again selection won't matter.
 699          */
 700         if (perf_select != 0) {
 701
 702                 /* Sort the device array by throughput  */
 703                 qsort(*dev_select, *num_selections,
 704                       sizeof(struct device_selection),
 705                       compare_select);
 706
 707                 if (*num_selected == 0) {
 708                         /*
 709                          * Here we select every device in the array, if it
 710                          * isn't already selected.  Because the 'selected'
 711                          * variable in the selection array entries contains
 712                          * the selection order, the devstats routine can show
 713                          * the devices that were selected first.
 714                          */
 715                         for (i = 0; i < *num_selections; i++) {
 716                                 if ((*dev_select)[i].selected == 0) {
 717                                         (*dev_select)[i].selected =
 718                                                 ++selection_number;
 719                                         (*num_selected)++;
 720                                 }
 721                         }
 722                 } else {
 723                         selection_number = 0;
 724                         for (i = 0; i < *num_selections; i++) {
 725                                 if ((*dev_select)[i].selected != 0) {
 726                                         (*dev_select)[i].selected =
 727                                                 ++selection_number;
 728                                 }
 729                         }
 730                 }
 731         }
 732
 733         /*
 734          * If we're in the "add" selection mode and if we haven't already
 735          * selected maxshowdevs number of devices, go through the array and
 736          * select any unselected devices.  If we're in "only" mode, we
 737          * obviously don't want to select anything other than what the user
 738          * specifies.  If we're in "remove" mode, it probably isn't a good
 739          * idea to go through and select any more devices, since we might
 740          * end up selecting something that the user wants removed.  Through
 741          * more complicated logic, we could actually figure this out, but
 742          * that would probably require combining this loop with the various
 743          * selections loops above.
 744          */
 745         if ((select_mode == DS_SELECT_ADD) && (*num_selected < maxshowdevs)) {
 746                 for (i = 0; i < *num_selections; i++)
 747                         if ((*dev_select)[i].selected == 0) {
 748                                 (*dev_select)[i].selected = ++selection_number;
 749                                 (*num_selected)++;
 750                         }
 751         }
 752
 753         /*
 754          * Look at the number of devices that have been selected.  If it
 755          * has changed, set the changed variable.  Otherwise, if we've
 756          * made a backup of the selection list, compare it to the current
 757          * selection list to see if the selected devices have changed.
 758          */
 759         if ((changed == 0) && (old_num_selected != *num_selected))
 760                 changed = 1;
 761         else if ((changed == 0) && (old_dev_select != NULL)) {
 762                 /*
 763                  * Now we go through the selection list and we look at
 764                  * it three different ways.
 765                  */
 766                 for (i = 0; (i < *num_selections) && (changed == 0) &&
 767                      (i < old_num_selections); i++) {
 768                         /*
 769                          * If the device at index i in both the new and old
 770                          * selection arrays has the same device number and
 771                          * selection status, it hasn't changed.  We
 772                          * continue on to the next index.
 773                          */
 774                         if (((*dev_select)[i].device_number ==
 775                              old_dev_select[i].device_number)
 776                          && ((*dev_select)[i].selected ==
 777                              old_dev_select[i].selected))
 778                                 continue;
 779
 780                         /*
 781                          * Now, if we're still going through the if
 782                          * statement, the above test wasn't true.  So we
 783                          * check here to see if the device at index i in
 784                          * the current array is the same as the device at
 785                          * index i in the old array.  If it is, that means
 786                          * that its selection number has changed.  Set
 787                          * changed to 1 and exit the loop.
 788                          */
 789                         else if ((*dev_select)[i].device_number ==
 790                                   old_dev_select[i].device_number) {
 791                                 changed = 1;
 792                                 break;
 793                         }
 794                         /*
 795                          * If we get here, then the device at index i in
 796                          * the current array isn't the same device as the
 797                          * device at index i in the old array.
 798                          */
 799                         else {
 800                                 found = 0;
 801
 802                                 /*
 803                                  * Search through the old selection array
 804                                  * looking for a device with the same
 805                                  * device number as the device at index i
 806                                  * in the current array.  If the selection
 807                                  * status is the same, then we mark it as
 808                                  * found.  If the selection status isn't
 809                                  * the same, we break out of the loop.
 810                                  * Since found isn't set, changed will be
 811                                  * set to 1 below.
 812                                  */
 813                                 for (j = 0; j < old_num_selections; j++) {
 814                                         if (((*dev_select)[i].device_number ==
 815                                               old_dev_select[j].device_number)
 816                                          && ((*dev_select)[i].selected ==
 817                                               old_dev_select[j].selected)){
 818                                                 found = 1;
 819                                                 break;
 820                                         }
 821                                         else if ((*dev_select)[i].device_number
 822                                             == old_dev_select[j].device_number)
 823                                                 break;
 824                                 }
 825                                 if (found == 0)
 826                                         changed = 1;
 827                         }
 828                 }
 829         }
 830         if (old_dev_select != NULL)
 831                 free(old_dev_select);
 832
 833         return(changed);
 834 }
 835
 836 /*
 837  * Comparison routine for qsort() above.  Note that the comparison here is
 838  * backwards -- generally, it should return a value to indicate whether
 839  * arg1 is <, =, or > arg2.  Instead, it returns the opposite.  The reason
 840  * it returns the opposite is so that the selection array will be sorted in
 841  * order of decreasing performance.  We sort on two parameters.  The first
 842  * sort key is whether or not one or the other of the devices in question
 843  * has been selected.  If one of them has, and the other one has not, the
 844  * selected device is automatically more important than the unselected
 845  * device.  If neither device is selected, we judge the devices based upon
 846  * performance.
 847  */
 848 static int
 849 compare_select(const void *arg1, const void *arg2)
 850 {
 851         if ((((const struct device_selection *)arg1)->selected)
 852          && (((const struct device_selection *)arg2)->selected == 0))
 853                 return(-1);
 854         else if ((((const struct device_selection *)arg1)->selected == 0)
 855               && (((const struct device_selection *)arg2)->selected))
 856                 return(1);
 857         else if (((const struct device_selection *)arg2)->bytes <
 858                  ((const struct device_selection *)arg1)->bytes)
 859                 return(-1);
 860         else if (((const struct device_selection *)arg2)->bytes >
 861                  ((const struct device_selection *)arg1)->bytes)
 862                 return(1);
 863         else
 864                 return(0);
 865 }
 866
 867 /*
 868  * Take a string with the general format "arg1,arg2,arg3", and build a
 869  * device matching expression from it.
 870  */
 871 int
 872 buildmatch(const char *match_str, struct devstat_match **matches,
 873            int *num_matches)
 874 {
 875         char *tstr[5];
 876         char **tempstr;
 877         char *matchbuf_orig;    /* strdup of match_str */
 878         char *matchbuf;         /* allow strsep to clobber */
 879         int num_args;
 880         int i, j;
 881         int retval = -1;
 882
 883         /* We can't do much without a string to parse */
 884         if (match_str == NULL) {
 885                 sprintf(devstat_errbuf, "%s: no match expression", __func__);
 886                 return(-1);
 887         }
 888
 889         /*
 890          * Break the (comma delimited) input string out into separate strings.
 891          * strsep is destructive, so copy the string first.
 892          */
 893         matchbuf = matchbuf_orig = strdup(match_str);
 894         if (matchbuf == NULL) {
 895                 sprintf(devstat_errbuf, "%s: out of memory", __func__);
 896                 return(-1);
 897         }
 898         for (tempstr = tstr, num_args  = 0;
 899              (*tempstr = strsep(&matchbuf, ",")) != NULL && (num_args < 5);
 900              num_args++)
 901                 if (**tempstr != '\0')
 902                         if (++tempstr >= &tstr[5])
 903                                 break;
 904
 905         /* The user gave us too many type arguments */
 906         if (num_args > 3) {
 907                 sprintf(devstat_errbuf, "%s: too many type arguments",
 908                         __func__);
 909                 goto cleanup;
 910         }
 911
 912         /*
 913          * Since you can't realloc a pointer that hasn't been malloced
 914          * first, we malloc first and then realloc.
 915          */
 916         if (*num_matches == 0)
 917                 *matches = (struct devstat_match *)malloc(
 918                            sizeof(struct devstat_match));
 919         else
 920                 *matches = (struct devstat_match *)realloc(*matches,
 921                           sizeof(struct devstat_match) * (*num_matches + 1));
 922
 923         /* Make sure the current entry is clear */
 924         bzero(&matches[0][*num_matches], sizeof(struct devstat_match));
 925
 926         /*
 927          * Step through the arguments the user gave us and build a device
 928          * matching expression from them.
 929          */
 930         for (i = 0; i < num_args; i++) {
 931                 char *tempstr2, *tempstr3;
 932
 933                 /*
 934                  * Get rid of leading white space.
 935                  */
 936                 tempstr2 = tstr[i];
 937                 while (isspace(*tempstr2) && (*tempstr2 != '\0'))
 938                         tempstr2++;
 939
 940                 /*
 941                  * Get rid of trailing white space.
 942                  */
 943                 tempstr3 = &tempstr2[strlen(tempstr2) - 1];
 944
 945                 while ((*tempstr3 != '\0') && (tempstr3 > tempstr2)
 946                     && (isspace(*tempstr3))) {
 947                         *tempstr3 = '\0';
 948                         tempstr3--;
 949                 }
 950
 951                 /*
 952                  * Go through the match table comparing the user's
 953                  * arguments to known device types, interfaces, etc.
 954                  */
 955                 for (j = 0; match_table[j].match_str != NULL; j++) {
 956                         /*
 957                          * We do case-insensitive matching, in case someone
 958                          * wants to enter "SCSI" instead of "scsi" or
 959                          * something like that.  Only compare as many
 960                          * characters as are in the string in the match
 961                          * table.  This should help if someone tries to use
 962                          * a super-long match expression.
 963                          */
 964                         if (strncasecmp(tempstr2, match_table[j].match_str,
 965                             strlen(match_table[j].match_str)) == 0) {
 966                                 /*
 967                                  * Make sure the user hasn't specified two
 968                                  * items of the same type, like "da" and
 969                                  * "cd".  One device cannot be both.
 970                                  */
 971                                 if (((*matches)[*num_matches].match_fields &
 972                                     match_table[j].match_field) != 0) {
 973                                         sprintf(devstat_errbuf,
 974                                                 "%s: cannot have more than "
 975                                                 "one match item in a single "
 976                                                 "category", __func__);
 977                                         goto cleanup;
 978                                 }
 979                                 /*
 980                                  * If we've gotten this far, we have a
 981                                  * winner.  Set the appropriate fields in
 982                                  * the match entry.
 983                                  */
 984                                 (*matches)[*num_matches].match_fields |=
 985                                         match_table[j].match_field;
 986                                 (*matches)[*num_matches].device_type |=
 987                                         match_table[j].type;
 988                                 (*matches)[*num_matches].num_match_categories++;
 989                                 break;
 990                         }
 991                 }
 992                 /*
 993                  * We should have found a match in the above for loop.  If
 994                  * not, that means the user entered an invalid device type
 995                  * or interface.
 996                  */
 997                 if ((*matches)[*num_matches].num_match_categories != (i + 1)) {
 998                         snprintf(devstat_errbuf, sizeof(devstat_errbuf),
 999                                 "%s: unknown match item \"%s\"", __func__,
1000                                 tstr[i]);
1001                         goto cleanup;
1002                 }
1003         }
1004
1005         (*num_matches)++;
1006         retval = 0;
1007 cleanup:
1008         free(matchbuf_orig);
1009         return(retval);
1010 }
1011
1012 /*
1013  * Compute a number of device statistics.  Only one field is mandatory, and
1014  * that is "current".  Everything else is optional.  The caller passes in
1015  * pointers to variables to hold the various statistics he desires.  If he
1016  * doesn't want a particular staistic, he should pass in a NULL pointer.
1017  * Return values:
1018  * 0   -- success
1019  * -1  -- failure
1020  */
1021 int
1022 compute_stats(struct devstat *current, struct devstat *previous,
1023               long double etime, u_int64_t *total_bytes,
1024               u_int64_t *total_transfers, u_int64_t *total_blocks,
1025               long double *kb_per_transfer, long double *transfers_per_second,
1026               long double *mb_per_second, long double *blocks_per_second,
1027               long double *ms_per_transaction)
1028 {
1029         u_int64_t totalbytes, totaltransfers, totalblocks;
1030
1031         /*
1032          * current is the only mandatory field.
1033          */
1034         if (current == NULL) {
1035                 sprintf(devstat_errbuf, "%s: current stats structure was NULL",
1036                         __func__);
1037                 return(-1);
1038         }
1039
1040         totalbytes = (current->bytes_written + current->bytes_read) -
1041                      ((previous) ? (previous->bytes_written +
1042                                     previous->bytes_read) : 0);
1043
1044         if (total_bytes)
1045                 *total_bytes = totalbytes;
1046
1047         totaltransfers = (current->num_reads +
1048                           current->num_writes +
1049                           current->num_other) -
1050                          ((previous) ?
1051                           (previous->num_reads +
1052                            previous->num_writes +
1053                            previous->num_other) : 0);
1054         if (total_transfers)
1055                 *total_transfers = totaltransfers;
1056
1057         if (transfers_per_second) {
1058                 if (etime > 0.0) {
1059                         *transfers_per_second = totaltransfers;
1060                         *transfers_per_second /= etime;
1061                 } else
1062                         *transfers_per_second = 0.0;
1063         }
1064
1065         if (kb_per_transfer) {
1066                 *kb_per_transfer = totalbytes;
1067                 *kb_per_transfer /= 1024;
1068                 if (totaltransfers > 0)
1069                         *kb_per_transfer /= totaltransfers;
1070                 else
1071                         *kb_per_transfer = 0.0;
1072         }
1073
1074         if (mb_per_second) {
1075                 *mb_per_second = totalbytes;
1076                 *mb_per_second /= 1024 * 1024;
1077                 if (etime > 0.0)
1078                         *mb_per_second /= etime;
1079                 else
1080                         *mb_per_second = 0.0;
1081         }
1082
1083         totalblocks = totalbytes;
1084         if (current->block_size > 0)
1085                 totalblocks /= current->block_size;
1086         else
1087                 totalblocks /= 512;
1088
1089         if (total_blocks)
1090                 *total_blocks = totalblocks;
1091
1092         if (blocks_per_second) {
1093                 *blocks_per_second = totalblocks;
1094                 if (etime > 0.0)
1095                         *blocks_per_second /= etime;
1096                 else
1097                         *blocks_per_second = 0.0;
1098         }
1099
1100         if (ms_per_transaction) {
1101                 if (totaltransfers > 0) {
1102                         *ms_per_transaction = etime;
1103                         *ms_per_transaction /= totaltransfers;
1104                         *ms_per_transaction *= 1000;
1105                 } else
1106                         *ms_per_transaction = 0.0;
1107         }
1108
1109         return(0);
1110 }
1111
1112 int
1113 compute_stats_read(struct devstat *current, struct devstat *previous,
1114               long double etime, u_int64_t *total_bytes,
1115               u_int64_t *total_transfers, u_int64_t *total_blocks,
1116               long double *kb_per_transfer, long double *transfers_per_second,
1117               long double *mb_per_second, long double *blocks_per_second,
1118               long double *ms_per_transaction)
1119 {
1120         u_int64_t totalbytes, totaltransfers, totalblocks;
1121
1122         /*
1123          * current is the only mandatory field.
1124          */
1125         if (current == NULL) {
1126                 sprintf(devstat_errbuf, "%s: current stats structure was NULL",
1127                         __func__);
1128                 return(-1);
1129         }
1130
1131         totalbytes = current->bytes_read -
1132                      (previous ? previous->bytes_read : 0);
1133
1134         if (total_bytes)
1135                 *total_bytes = totalbytes;
1136
1137         totaltransfers = current->num_reads -
1138                          (previous ? previous->num_reads : 0);
1139         if (total_transfers)
1140                 *total_transfers = totaltransfers;
1141
1142         if (transfers_per_second) {
1143                 if (etime > 0.0) {
1144                         *transfers_per_second = totaltransfers;
1145                         *transfers_per_second /= etime;
1146                 } else
1147                         *transfers_per_second = 0.0;
1148         }
1149
1150         if (kb_per_transfer) {
1151                 *kb_per_transfer = totalbytes;
1152                 *kb_per_transfer /= 1024;
1153                 if (totaltransfers > 0)
1154                         *kb_per_transfer /= totaltransfers;
1155                 else
1156                         *kb_per_transfer = 0.0;
1157         }
1158
1159         if (mb_per_second) {
1160                 *mb_per_second = totalbytes;
1161                 *mb_per_second /= 1024 * 1024;
1162                 if (etime > 0.0)
1163                         *mb_per_second /= etime;
1164                 else
1165                         *mb_per_second = 0.0;
1166         }
1167
1168         totalblocks = totalbytes;
1169         if (current->block_size > 0)
1170                 totalblocks /= current->block_size;
1171         else
1172                 totalblocks /= 512;
1173
1174         if (total_blocks)
1175                 *total_blocks = totalblocks;
1176
1177         if (blocks_per_second) {
1178                 *blocks_per_second = totalblocks;
1179                 if (etime > 0.0)
1180                         *blocks_per_second /= etime;
1181                 else
1182                         *blocks_per_second = 0.0;
1183         }
1184
1185         if (ms_per_transaction) {
1186                 if (totaltransfers > 0) {
1187                         *ms_per_transaction = etime;
1188                         *ms_per_transaction /= totaltransfers;
1189                         *ms_per_transaction *= 1000;
1190                 } else
1191                         *ms_per_transaction = 0.0;
1192         }
1193
1194         return(0);
1195 }
1196
1197 int
1198 compute_stats_write(struct devstat *current, struct devstat *previous,
1199               long double etime, u_int64_t *total_bytes,
1200               u_int64_t *total_transfers, u_int64_t *total_blocks,
1201               long double *kb_per_transfer, long double *transfers_per_second,
1202               long double *mb_per_second, long double *blocks_per_second,
1203               long double *ms_per_transaction)
1204 {
1205         u_int64_t totalbytes, totaltransfers, totalblocks;
1206
1207         /*
1208          * current is the only mandatory field.
1209          */
1210         if (current == NULL) {
1211                 sprintf(devstat_errbuf, "%s: current stats structure was NULL",
1212                         __func__);
1213                 return(-1);
1214         }
1215
1216         totalbytes = current->bytes_written -
1217                      (previous ? previous->bytes_written : 0);
1218
1219         if (total_bytes)
1220                 *total_bytes = totalbytes;
1221
1222         totaltransfers = current->num_writes -
1223                          (previous ? previous->num_writes : 0);
1224         if (total_transfers)
1225                 *total_transfers = totaltransfers;
1226
1227         if (transfers_per_second) {
1228                 if (etime > 0.0) {
1229                         *transfers_per_second = totaltransfers;
1230                         *transfers_per_second /= etime;
1231                 } else
1232                         *transfers_per_second = 0.0;
1233         }
1234
1235         if (kb_per_transfer) {
1236                 *kb_per_transfer = totalbytes;
1237                 *kb_per_transfer /= 1024;
1238                 if (totaltransfers > 0)
1239                         *kb_per_transfer /= totaltransfers;
1240                 else
1241                         *kb_per_transfer = 0.0;
1242         }
1243
1244         if (mb_per_second) {
1245                 *mb_per_second = totalbytes;
1246                 *mb_per_second /= 1024 * 1024;
1247                 if (etime > 0.0)
1248                         *mb_per_second /= etime;
1249                 else
1250                         *mb_per_second = 0.0;
1251         }
1252
1253         totalblocks = totalbytes;
1254         if (current->block_size > 0)
1255                 totalblocks /= current->block_size;
1256         else
1257                 totalblocks /= 512;
1258
1259         if (total_blocks)
1260                 *total_blocks = totalblocks;
1261
1262         if (blocks_per_second) {
1263                 *blocks_per_second = totalblocks;
1264                 if (etime > 0.0)
1265                         *blocks_per_second /= etime;
1266                 else
1267                         *blocks_per_second = 0.0;
1268         }
1269
1270         if (ms_per_transaction) {
1271                 if (totaltransfers > 0) {
1272                         *ms_per_transaction = etime;
1273                         *ms_per_transaction /= totaltransfers;
1274                         *ms_per_transaction *= 1000;
1275                 } else
1276                         *ms_per_transaction = 0.0;
1277         }
1278
1279         return(0);
1280 }
1281
1282 long double
1283 compute_etime(struct timeval cur_time, struct timeval prev_time)
1284 {
1285         struct timeval busy_time;
1286         u_int64_t busy_usec;
1287         long double etime;
1288
1289         timersub(&cur_time, &prev_time, &busy_time);
1290
1291         busy_usec = busy_time.tv_sec;
1292         busy_usec *= 1000000;
1293         busy_usec += busy_time.tv_usec;
1294         etime = busy_usec;
1295         etime /= 1000000;
1296
1297         return(etime);
1298 }