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         {"xa",          DEVSTAT_TYPE_DIRECT,    DEVSTAT_MATCH_TYPE},
  53         {"cd",          DEVSTAT_TYPE_CDROM,     DEVSTAT_MATCH_TYPE},
  54         {"scsi",        DEVSTAT_TYPE_IF_SCSI,   DEVSTAT_MATCH_IF},
  55         {"ide",         DEVSTAT_TYPE_IF_IDE,    DEVSTAT_MATCH_IF},
  56         {"other",       DEVSTAT_TYPE_IF_OTHER,  DEVSTAT_MATCH_IF},
  57         {"worm",        DEVSTAT_TYPE_WORM,      DEVSTAT_MATCH_TYPE},
  58         {"sa",          DEVSTAT_TYPE_SEQUENTIAL,DEVSTAT_MATCH_TYPE},
  59         {"pass",        DEVSTAT_TYPE_PASS,      DEVSTAT_MATCH_PASS},
  60         {"optical",     DEVSTAT_TYPE_OPTICAL,   DEVSTAT_MATCH_TYPE},
  61         {"array",       DEVSTAT_TYPE_STORARRAY, DEVSTAT_MATCH_TYPE},
  62         {"changer",     DEVSTAT_TYPE_CHANGER,   DEVSTAT_MATCH_TYPE},
  63         {"scanner",     DEVSTAT_TYPE_SCANNER,   DEVSTAT_MATCH_TYPE},
  64         {"printer",     DEVSTAT_TYPE_PRINTER,   DEVSTAT_MATCH_TYPE},
  65         {"floppy",      DEVSTAT_TYPE_FLOPPY,    DEVSTAT_MATCH_TYPE},
  66         {"proc",        DEVSTAT_TYPE_PROCESSOR, DEVSTAT_MATCH_TYPE},
  67         {"comm",        DEVSTAT_TYPE_COMM,      DEVSTAT_MATCH_TYPE},
  68         {"enclosure",   DEVSTAT_TYPE_ENCLOSURE, DEVSTAT_MATCH_TYPE},
  69         {NULL,          0,                      0}
  70 };
  71
  72 /*
  73  * Local function declarations.
  74  */
  75 static int compare_select(const void *arg1, const void *arg2);
  76
  77 int
  78 getnumdevs(void)
  79 {
  80         size_t numdevsize;
  81         int numdevs;
  82         const char *func_name = "getnumdevs";
  83
  84         numdevsize = sizeof(int);
  85
  86         /*
  87          * Find out how many devices we have in the system.
  88          */
  89         if (sysctlbyname("kern.devstat.numdevs", &numdevs,
  90                          &numdevsize, NULL, 0) == -1) {
  91                 sprintf(devstat_errbuf, "%s: error getting number of devices\n"
  92                         "%s: %s", func_name, func_name, strerror(errno));
  93                 return(-1);
  94         } else
  95                 return(numdevs);
  96 }
  97
  98 /*
  99  * This is an easy way to get the generation number, but the generation is
 100  * supplied in a more atmoic manner by the kern.devstat.all sysctl.
 101  * Because this generation sysctl is separate from the statistics sysctl,
 102  * the device list and the generation could change between the time that
 103  * this function is called and the device list is retreived.
 104  */
 105 long
 106 getgeneration(void)
 107 {
 108         size_t gensize;
 109         long generation;
 110         const char *func_name = "getgeneration";
 111
 112         gensize = sizeof(long);
 113
 114         /*
 115          * Get the current generation number.
 116          */
 117         if (sysctlbyname("kern.devstat.generation", &generation,
 118                          &gensize, NULL, 0) == -1) {
 119                 sprintf(devstat_errbuf,"%s: error getting devstat generation\n"
 120                         "%s: %s", func_name, func_name, strerror(errno));
 121                 return(-1);
 122         } else
 123                 return(generation);
 124 }
 125
 126 /*
 127  * Get the current devstat version.  The return value of this function
 128  * should be compared with DEVSTAT_VERSION, which is defined in
 129  * sys/devicestat.h.  This will enable userland programs to determine
 130  * whether they are out of sync with the kernel.
 131  */
 132 int
 133 getversion(void)
 134 {
 135         size_t versize;
 136         int version;
 137         const char *func_name = "getversion";
 138
 139         versize = sizeof(int);
 140
 141         /*
 142          * Get the current devstat version.
 143          */
 144         if (sysctlbyname("kern.devstat.version", &version, &versize,
 145                          NULL, 0) == -1) {
 146                 sprintf(devstat_errbuf, "%s: error getting devstat version\n"
 147                         "%s: %s", func_name, func_name, strerror(errno));
 148                 return(-1);
 149         } else
 150                 return(version);
 151 }
 152
 153 /*
 154  * Check the devstat version we know about against the devstat version the
 155  * kernel knows about.  If they don't match, print an error into the
 156  * devstat error buffer, and return -1.  If they match, return 0.
 157  */
 158 int
 159 checkversion(void)
 160 {
 161         int retval = 0;
 162         int errlen = 0;
 163         const char *func_name = "checkversion";
 164         int version;
 165
 166         version = getversion();
 167
 168         if (version != DEVSTAT_VERSION) {
 169                 int buflen = 0;
 170                 char tmpstr[256];
 171
 172                 /*
 173                  * This is really pretty silly, but basically the idea is
 174                  * that if getversion() returns an error (i.e. -1), then it
 175                  * has printed an error message in the buffer.  Therefore,
 176                  * we need to add a \n to the end of that message before we
 177                  * print our own message in the buffer.
 178                  */
 179                 if (version == -1) {
 180                         buflen = strlen(devstat_errbuf);
 181                         errlen = snprintf(tmpstr, sizeof(tmpstr), "\n");
 182                         strncat(devstat_errbuf, tmpstr,
 183                                 DEVSTAT_ERRBUF_SIZE - buflen - 1);
 184                         buflen += errlen;
 185                 }
 186
 187                 errlen = snprintf(tmpstr, sizeof(tmpstr),
 188                                   "%s: userland devstat version %d is not "
 189                                   "the same as the kernel\n%s: devstat "
 190                                   "version %d\n", func_name, DEVSTAT_VERSION,
 191                                   func_name, version);
 192
 193                 if (version == -1) {
 194                         strncat(devstat_errbuf, tmpstr,
 195                                 DEVSTAT_ERRBUF_SIZE - buflen - 1);
 196                         buflen += errlen;
 197                 } else {
 198                         strncpy(devstat_errbuf, tmpstr, DEVSTAT_ERRBUF_SIZE);
 199                         devstat_errbuf[DEVSTAT_ERRBUF_SIZE - 1] = '\0';
 200                 }
 201
 202                 if (version < DEVSTAT_VERSION)
 203                         snprintf(tmpstr, sizeof(tmpstr),
 204                                  "%s: libdevstat newer than kernel\n",
 205                                  func_name);
 206                 else
 207                         snprintf(tmpstr, sizeof(tmpstr),
 208                                  "%s: kernel newer than libdevstat\n",
 209                                  func_name);
 210
 211                 strncat(devstat_errbuf, tmpstr,
 212                         DEVSTAT_ERRBUF_SIZE - buflen - 1);
 213
 214                 retval = -1;
 215         }
 216
 217         return(retval);
 218 }
 219
 220 /*
 221  * Get the current list of devices and statistics, and the current
 222  * generation number.
 223  *
 224  * Return values:
 225  * -1  -- error
 226  *  0  -- device list is unchanged
 227  *  1  -- device list has changed
 228  */
 229 int
 230 getdevs(struct statinfo *stats)
 231 {
 232         int error;
 233         size_t dssize;
 234         long oldgeneration;
 235         int retval = 0;
 236         struct devinfo *dinfo;
 237         const char *func_name = "getdevs";
 238
 239         dinfo = stats->dinfo;
 240
 241         if (dinfo == NULL) {
 242                 sprintf(devstat_errbuf, "%s: stats->dinfo was NULL", func_name);
 243                 return(-1);
 244         }
 245
 246         oldgeneration = dinfo->generation;
 247
 248         /*
 249          * If this is our first time through, mem_ptr will be null.
 250          */
 251         if (dinfo->mem_ptr == NULL) {
 252                 /*
 253                  * Get the number of devices.  If it's negative, it's an
 254                  * error.  Don't bother setting the error string, since
 255                  * getnumdevs() has already done that for us.
 256                  */
 257                 if ((dinfo->numdevs = getnumdevs()) < 0)
 258                         return(-1);
 259
 260                 /*
 261                  * The kern.devstat.all sysctl returns the current generation
 262                  * number, as well as all the devices.  So we need four
 263                  * bytes more.
 264                  */
 265                 dssize =(dinfo->numdevs * sizeof(struct devstat)) +sizeof(long);
 266                 dinfo->mem_ptr = (u_int8_t *)malloc(dssize);
 267         } else
 268                 dssize =(dinfo->numdevs * sizeof(struct devstat)) +sizeof(long);
 269
 270         /* Get the current time when we get the stats */
 271         gettimeofday(&stats->busy_time, NULL);
 272
 273         /*
 274          * Request all of the devices.  We only really allow for one
 275          * ENOMEM failure.  It would, of course, be possible to just go in
 276          * a loop and keep reallocing the device structure until we don't
 277          * get ENOMEM back.  I'm not sure it's worth it, though.  If
 278          * devices are being added to the system that quickly, maybe the
 279          * user can just wait until all devices are added.
 280          */
 281         if ((error = sysctlbyname("kern.devstat.all", dinfo->mem_ptr,
 282              &dssize, NULL, 0)) == -1) {
 283                 /*
 284                  * If we get ENOMEM back, that means that there are
 285                  * more devices now, so we need to allocate more
 286                  * space for the device array.
 287                  */
 288                 if (errno == ENOMEM) {
 289                         /*
 290                          * No need to set the error string here, getnumdevs()
 291                          * will do that if it fails.
 292                          */
 293                         if ((dinfo->numdevs = getnumdevs()) < 0)
 294                                 return(-1);
 295
 296                         dssize = (dinfo->numdevs * sizeof(struct devstat)) +
 297                                 sizeof(long);
 298                         dinfo->mem_ptr = (u_int8_t *)realloc(dinfo->mem_ptr,
 299                                                              dssize);
 300                         if ((error = sysctlbyname("kern.devstat.all",
 301                             dinfo->mem_ptr, &dssize, NULL, 0)) == -1) {
 302                                 sprintf(devstat_errbuf,
 303                                         "%s: error getting device stats\n"
 304                                         "%s: %s", func_name, func_name,
 305                                         strerror(errno));
 306                                 return(-1);
 307                         }
 308                 } else {
 309                         sprintf(devstat_errbuf,
 310                                 "%s: error getting device stats\n"
 311                                 "%s: %s", func_name, func_name,
 312                                 strerror(errno));
 313                         return(-1);
 314                 }
 315         }
 316
 317         /*
 318          * The sysctl spits out the generation as the first four bytes,
 319          * then all of the device statistics structures.
 320          */
 321         dinfo->generation = *(long *)dinfo->mem_ptr;
 322
 323         /*
 324          * If the generation has changed, and if the current number of
 325          * devices is not the same as the number of devices recorded in the
 326          * devinfo structure, it is likely that the device list has shrunk.
 327          * The reason that it is likely that the device list has shrunk in
 328          * this case is that if the device list has grown, the sysctl above
 329          * will return an ENOMEM error, and we will reset the number of
 330          * devices and reallocate the device array.  If the second sysctl
 331          * fails, we will return an error and therefore never get to this
 332          * point.  If the device list has shrunk, the sysctl will not
 333          * return an error since we have more space allocated than is
 334          * necessary.  So, in the shrinkage case, we catch it here and
 335          * reallocate the array so that we don't use any more space than is
 336          * necessary.
 337          */
 338         if (oldgeneration != dinfo->generation) {
 339                 if (getnumdevs() != dinfo->numdevs) {
 340                         if ((dinfo->numdevs = getnumdevs()) < 0)
 341                                 return(-1);
 342                         dssize = (dinfo->numdevs * sizeof(struct devstat)) +
 343                                 sizeof(long);
 344                         dinfo->mem_ptr = (u_int8_t *)realloc(dinfo->mem_ptr,
 345                                                              dssize);
 346                 }
 347                 retval = 1;
 348         }
 349
 350         dinfo->devices = (struct devstat *)(dinfo->mem_ptr + sizeof(long));
 351
 352         return(retval);
 353 }
 354
 355 /*
 356  * selectdevs():
 357  *
 358  * Devices are selected/deselected based upon the following criteria:
 359  * - devices specified by the user on the command line
 360  * - devices matching any device type expressions given on the command line
 361  * - devices with the highest I/O, if 'top' mode is enabled
 362  * - the first n unselected devices in the device list, if maxshowdevs
 363  *   devices haven't already been selected and if the user has not
 364  *   specified any devices on the command line and if we're in "add" mode.
 365  *
 366  * Input parameters:
 367  * - device selection list (dev_select)
 368  * - current number of devices selected (num_selected)
 369  * - total number of devices in the selection list (num_selections)
 370  * - devstat generation as of the last time selectdevs() was called
 371  *   (select_generation)
 372  * - current devstat generation (current_generation)
 373  * - current list of devices and statistics (devices)
 374  * - number of devices in the current device list (numdevs)
 375  * - compiled version of the command line device type arguments (matches)
 376  *   - This is optional.  If the number of devices is 0, this will be ignored.
 377  *   - The matching code pays attention to the current selection mode.  So
 378  *     if you pass in a matching expression, it will be evaluated based
 379  *     upon the selection mode that is passed in.  See below for details.
 380  * - number of device type matching expressions (num_matches)
 381  *   - Set to 0 to disable the matching code.
 382  * - list of devices specified on the command line by the user (dev_selections)
 383  * - number of devices selected on the command line by the user
 384  *   (num_dev_selections)
 385  * - Our selection mode.  There are four different selection modes:
 386  *      - add mode.  (DS_SELECT_ADD) Any devices matching devices explicitly
 387  *        selected by the user or devices matching a pattern given by the
 388  *        user will be selected in addition to devices that are already
 389  *        selected.  Additional devices will be selected, up to maxshowdevs
 390  *        number of devices.
 391  *      - only mode. (DS_SELECT_ONLY)  Only devices matching devices
 392  *        explicitly given by the user or devices matching a pattern
 393  *        given by the user will be selected.  No other devices will be
 394  *        selected.
 395  *      - addonly mode.  (DS_SELECT_ADDONLY)  This is similar to add and
 396  *        only.  Basically, this will not de-select any devices that are
 397  *        current selected, as only mode would, but it will also not
 398  *        gratuitously select up to maxshowdevs devices as add mode would.
 399  *      - remove mode.  (DS_SELECT_REMOVE)  Any devices matching devices
 400  *        explicitly selected by the user or devices matching a pattern
 401  *        given by the user will be de-selected.
 402  * - maximum number of devices we can select (maxshowdevs)
 403  * - flag indicating whether or not we're in 'top' mode (perf_select)
 404  *
 405  * Output data:
 406  * - the device selection list may be modified and passed back out
 407  * - the number of devices selected and the total number of items in the
 408  *   device selection list may be changed
 409  * - the selection generation may be changed to match the current generation
 410  *
 411  * Return values:
 412  * -1  -- error
 413  *  0  -- selected devices are unchanged
 414  *  1  -- selected devices changed
 415  */
 416 int
 417 selectdevs(struct device_selection **dev_select, int *num_selected,
 418            int *num_selections, long *select_generation,
 419            long current_generation, struct devstat *devices, int numdevs,
 420            struct devstat_match *matches, int num_matches,
 421            char **dev_selections, int num_dev_selections,
 422            devstat_select_mode select_mode, int maxshowdevs, int perf_select)
 423 {
 424         int i, j, k;
 425         int init_selections = 0, init_selected_var = 0;
 426         struct device_selection *old_dev_select = NULL;
 427         int old_num_selections = 0, old_num_selected;
 428         int selection_number = 0;
 429         int changed = 0, found = 0;
 430
 431         if ((dev_select == NULL) || (devices == NULL) || (numdevs <= 0))
 432                 return(-1);
 433
 434         /*
 435          * We always want to make sure that we have as many dev_select
 436          * entries as there are devices.
 437          */
 438         /*
 439          * In this case, we haven't selected devices before.
 440          */
 441         if (*dev_select == NULL) {
 442                 *dev_select = (struct device_selection *)malloc(numdevs *
 443                         sizeof(struct device_selection));
 444                 *select_generation = current_generation;
 445                 init_selections = 1;
 446                 changed = 1;
 447         /*
 448          * In this case, we have selected devices before, but the device
 449          * list has changed since we last selected devices, so we need to
 450          * either enlarge or reduce the size of the device selection list.
 451          */
 452         } else if (*num_selections != numdevs) {
 453                 *dev_select = (struct device_selection *)realloc(*dev_select,
 454                         numdevs * sizeof(struct device_selection));
 455                 *select_generation = current_generation;
 456                 init_selections = 1;
 457         /*
 458          * In this case, we've selected devices before, and the selection
 459          * list is the same size as it was the last time, but the device
 460          * list has changed.
 461          */
 462         } else if (*select_generation < current_generation) {
 463                 *select_generation = current_generation;
 464                 init_selections = 1;
 465         }
 466
 467         /*
 468          * If we're in "only" mode, we want to clear out the selected
 469          * variable since we're going to select exactly what the user wants
 470          * this time through.
 471          */
 472         if (select_mode == DS_SELECT_ONLY)
 473                 init_selected_var = 1;
 474
 475         /*
 476          * In all cases, we want to back up the number of selected devices.
 477          * It is a quick and accurate way to determine whether the selected
 478          * devices have changed.
 479          */
 480         old_num_selected = *num_selected;
 481
 482         /*
 483          * We want to make a backup of the current selection list if
 484          * the list of devices has changed, or if we're in performance
 485          * selection mode.  In both cases, we don't want to make a backup
 486          * if we already know for sure that the list will be different.
 487          * This is certainly the case if this is our first time through the
 488          * selection code.
 489          */
 490         if (((init_selected_var != 0) || (init_selections != 0)
 491          || (perf_select != 0)) && (changed == 0)){
 492                 old_dev_select = (struct device_selection *)malloc(
 493                     *num_selections * sizeof(struct device_selection));
 494                 old_num_selections = *num_selections;
 495                 bcopy(*dev_select, old_dev_select,
 496                     sizeof(struct device_selection) * *num_selections);
 497         }
 498
 499         if (init_selections != 0) {
 500                 bzero(*dev_select, sizeof(struct device_selection) * numdevs);
 501
 502                 for (i = 0; i < numdevs; i++) {
 503                         (*dev_select)[i].device_number =
 504                                 devices[i].device_number;
 505                         strncpy((*dev_select)[i].device_name,
 506                                 devices[i].device_name,
 507                                 DEVSTAT_NAME_LEN);
 508                         (*dev_select)[i].device_name[DEVSTAT_NAME_LEN - 1]='\0';
 509                         (*dev_select)[i].unit_number = devices[i].unit_number;
 510                         (*dev_select)[i].position = i;
 511                 }
 512                 *num_selections = numdevs;
 513         } else if (init_selected_var != 0) {
 514                 for (i = 0; i < numdevs; i++)
 515                         (*dev_select)[i].selected = 0;
 516         }
 517
 518         /* we haven't gotten around to selecting anything yet.. */
 519         if ((select_mode == DS_SELECT_ONLY) || (init_selections != 0)
 520          || (init_selected_var != 0))
 521                 *num_selected = 0;
 522
 523         /*
 524          * Look through any devices the user specified on the command line
 525          * and see if they match known devices.  If so, select them.
 526          */
 527         for (i = 0; (i < *num_selections) && (num_dev_selections > 0); i++) {
 528                 char tmpstr[80];
 529
 530                 snprintf(tmpstr, sizeof(tmpstr), "%s%d",
 531                         (*dev_select)[i].device_name,
 532                         (*dev_select)[i].unit_number);
 533                 for (j = 0; j < num_dev_selections; j++) {
 534                         if (strcmp(tmpstr, dev_selections[j]) == 0) {
 535                                 /*
 536                                  * Here we do different things based on the
 537                                  * mode we're in.  If we're in add or
 538                                  * addonly mode, we only select this device
 539                                  * if it hasn't already been selected.
 540                                  * Otherwise, we would be unnecessarily
 541                                  * changing the selection order and
 542                                  * incrementing the selection count.  If
 543                                  * we're in only mode, we unconditionally
 544                                  * select this device, since in only mode
 545                                  * any previous selections are erased and
 546                                  * manually specified devices are the first
 547                                  * ones to be selected.  If we're in remove
 548                                  * mode, we de-select the specified device and
 549                                  * decrement the selection count.
 550                                  */
 551                                 switch(select_mode) {
 552                                 case DS_SELECT_ADD:
 553                                 case DS_SELECT_ADDONLY:
 554                                         if ((*dev_select)[i].selected)
 555                                                 break;
 556                                         /* FALLTHROUGH */
 557                                 case DS_SELECT_ONLY:
 558                                         (*dev_select)[i].selected =
 559                                                 ++selection_number;
 560                                         (*num_selected)++;
 561                                         break;
 562                                 case DS_SELECT_REMOVE:
 563                                         (*dev_select)[i].selected = 0;
 564                                         (*num_selected)--;
 565                                         /*
 566                                          * This isn't passed back out, we
 567                                          * just use it to keep track of
 568                                          * how many devices we've removed.
 569                                          */
 570                                         num_dev_selections--;
 571                                         break;
 572                                 }
 573                                 break;
 574                         }
 575                 }
 576         }
 577
 578         /*
 579          * Go through the user's device type expressions and select devices
 580          * accordingly.  We only do this if the number of devices already
 581          * selected is less than the maximum number we can show.
 582          */
 583         for (i = 0; (i < num_matches) && (*num_selected < maxshowdevs); i++) {
 584                 /* We should probably indicate some error here */
 585                 if ((matches[i].match_fields == DEVSTAT_MATCH_NONE)
 586                  || (matches[i].num_match_categories <= 0))
 587                         continue;
 588
 589                 for (j = 0; j < numdevs; j++) {
 590                         int num_match_categories;
 591
 592                         num_match_categories = matches[i].num_match_categories;
 593
 594                         /*
 595                          * Determine whether or not the current device
 596                          * matches the given matching expression.  This if
 597                          * statement consists of three components:
 598                          *   - the device type check
 599                          *   - the device interface check
 600                          *   - the passthrough check
 601                          * If a the matching test is successful, it
 602                          * decrements the number of matching categories,
 603                          * and if we've reached the last element that
 604                          * needed to be matched, the if statement succeeds.
 605                          *
 606                          */
 607                         if ((((matches[i].match_fields & DEVSTAT_MATCH_TYPE)!=0)
 608                           && ((devices[j].device_type & DEVSTAT_TYPE_MASK) ==
 609                                 (matches[i].device_type & DEVSTAT_TYPE_MASK))
 610                           &&(((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
 611                            || (((matches[i].match_fields &
 612                                 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_IF) != 0)
 617                           && ((devices[j].device_type & DEVSTAT_TYPE_IF_MASK) ==
 618                                 (matches[i].device_type & DEVSTAT_TYPE_IF_MASK))
 619                           &&(((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
 620                            || (((matches[i].match_fields &
 621                                 DEVSTAT_MATCH_PASS) == 0)
 622                             && ((devices[j].device_type &
 623                                 DEVSTAT_TYPE_PASS) == 0)))
 624                           && (--num_match_categories == 0))
 625                          || (((matches[i].match_fields & DEVSTAT_MATCH_PASS)!=0)
 626                           && ((devices[j].device_type & DEVSTAT_TYPE_PASS) != 0)
 627                           && (--num_match_categories == 0))) {
 628
 629                                 /*
 630                                  * This is probably a non-optimal solution
 631                                  * to the problem that the devices in the
 632                                  * device list will not be in the same
 633                                  * order as the devices in the selection
 634                                  * array.
 635                                  */
 636                                 for (k = 0; k < numdevs; k++) {
 637                                         if ((*dev_select)[k].position == j) {
 638                                                 found = 1;
 639                                                 break;
 640                                         }
 641                                 }
 642
 643                                 /*
 644                                  * There shouldn't be a case where a device
 645                                  * in the device list is not in the
 646                                  * selection list...but it could happen.
 647                                  */
 648                                 if (found != 1) {
 649                                         fprintf(stderr, "selectdevs: couldn't"
 650                                                 " find %s%d in selection "
 651                                                 "list\n",
 652                                                 devices[j].device_name,
 653                                                 devices[j].unit_number);
 654                                         break;
 655                                 }
 656
 657                                 /*
 658                                  * We do different things based upon the
 659                                  * mode we're in.  If we're in add or only
 660                                  * mode, we go ahead and select this device
 661                                  * if it hasn't already been selected.  If
 662                                  * it has already been selected, we leave
 663                                  * it alone so we don't mess up the
 664                                  * selection ordering.  Manually specified
 665                                  * devices have already been selected, and
 666                                  * they have higher priority than pattern
 667                                  * matched devices.  If we're in remove
 668                                  * mode, we de-select the given device and
 669                                  * decrement the selected count.
 670                                  */
 671                                 switch(select_mode) {
 672                                 case DS_SELECT_ADD:
 673                                 case DS_SELECT_ADDONLY:
 674                                 case DS_SELECT_ONLY:
 675                                         if ((*dev_select)[k].selected != 0)
 676                                                 break;
 677                                         (*dev_select)[k].selected =
 678                                                 ++selection_number;
 679                                         (*num_selected)++;
 680                                         break;
 681                                 case DS_SELECT_REMOVE:
 682                                         (*dev_select)[k].selected = 0;
 683                                         (*num_selected)--;
 684                                         break;
 685                                 }
 686                         }
 687                 }
 688         }
 689
 690         /*
 691          * Here we implement "top" mode.  Devices are sorted in the
 692          * selection array based on two criteria:  whether or not they are
 693          * selected (not selection number, just the fact that they are
 694          * selected!) and the number of bytes in the "bytes" field of the
 695          * selection structure.  The bytes field generally must be kept up
 696          * by the user.  In the future, it may be maintained by library
 697          * functions, but for now the user has to do the work.
 698          *
 699          * At first glance, it may seem wrong that we don't go through and
 700          * select every device in the case where the user hasn't specified
 701          * any devices or patterns.  In fact, though, it won't make any
 702          * difference in the device sorting.  In that particular case (i.e.
 703          * when we're in "add" or "only" mode, and the user hasn't
 704          * specified anything) the first time through no devices will be
 705          * selected, so the only criterion used to sort them will be their
 706          * performance.  The second time through, and every time thereafter,
 707          * all devices will be selected, so again selection won't matter.
 708          */
 709         if (perf_select != 0) {
 710
 711                 /* Sort the device array by throughput  */
 712                 qsort(*dev_select, *num_selections,
 713                       sizeof(struct device_selection),
 714                       compare_select);
 715
 716                 if (*num_selected == 0) {
 717                         /*
 718                          * Here we select every device in the array, if it
 719                          * isn't already selected.  Because the 'selected'
 720                          * variable in the selection array entries contains
 721                          * the selection order, the devstats routine can show
 722                          * the devices that were selected first.
 723                          */
 724                         for (i = 0; i < *num_selections; i++) {
 725                                 if ((*dev_select)[i].selected == 0) {
 726                                         (*dev_select)[i].selected =
 727                                                 ++selection_number;
 728                                         (*num_selected)++;
 729                                 }
 730                         }
 731                 } else {
 732                         selection_number = 0;
 733                         for (i = 0; i < *num_selections; i++) {
 734                                 if ((*dev_select)[i].selected != 0) {
 735                                         (*dev_select)[i].selected =
 736                                                 ++selection_number;
 737                                 }
 738                         }
 739                 }
 740         }
 741
 742         /*
 743          * If we're in the "add" selection mode and if we haven't already
 744          * selected maxshowdevs number of devices, go through the array and
 745          * select any unselected devices.  If we're in "only" mode, we
 746          * obviously don't want to select anything other than what the user
 747          * specifies.  If we're in "remove" mode, it probably isn't a good
 748          * idea to go through and select any more devices, since we might
 749          * end up selecting something that the user wants removed.  Through
 750          * more complicated logic, we could actually figure this out, but
 751          * that would probably require combining this loop with the various
 752          * selections loops above.
 753          */
 754         if ((select_mode == DS_SELECT_ADD) && (*num_selected < maxshowdevs)) {
 755                 for (i = 0; i < *num_selections; i++)
 756                         if ((*dev_select)[i].selected == 0) {
 757                                 (*dev_select)[i].selected = ++selection_number;
 758                                 (*num_selected)++;
 759                         }
 760         }
 761
 762         /*
 763          * Look at the number of devices that have been selected.  If it
 764          * has changed, set the changed variable.  Otherwise, if we've
 765          * made a backup of the selection list, compare it to the current
 766          * selection list to see if the selected devices have changed.
 767          */
 768         if ((changed == 0) && (old_num_selected != *num_selected))
 769                 changed = 1;
 770         else if ((changed == 0) && (old_dev_select != NULL)) {
 771                 /*
 772                  * Now we go through the selection list and we look at
 773                  * it three different ways.
 774                  */
 775                 for (i = 0; (i < *num_selections) && (changed == 0) &&
 776                      (i < old_num_selections); i++) {
 777                         /*
 778                          * If the device at index i in both the new and old
 779                          * selection arrays has the same device number and
 780                          * selection status, it hasn't changed.  We
 781                          * continue on to the next index.
 782                          */
 783                         if (((*dev_select)[i].device_number ==
 784                              old_dev_select[i].device_number)
 785                          && ((*dev_select)[i].selected ==
 786                              old_dev_select[i].selected))
 787                                 continue;
 788
 789                         /*
 790                          * Now, if we're still going through the if
 791                          * statement, the above test wasn't true.  So we
 792                          * check here to see if the device at index i in
 793                          * the current array is the same as the device at
 794                          * index i in the old array.  If it is, that means
 795                          * that its selection number has changed.  Set
 796                          * changed to 1 and exit the loop.
 797                          */
 798                         else if ((*dev_select)[i].device_number ==
 799                                   old_dev_select[i].device_number) {
 800                                 changed = 1;
 801                                 break;
 802                         }
 803                         /*
 804                          * If we get here, then the device at index i in
 805                          * the current array isn't the same device as the
 806                          * device at index i in the old array.
 807                          */
 808                         else {
 809                                 found = 0;
 810
 811                                 /*
 812                                  * Search through the old selection array
 813                                  * looking for a device with the same
 814                                  * device number as the device at index i
 815                                  * in the current array.  If the selection
 816                                  * status is the same, then we mark it as
 817                                  * found.  If the selection status isn't
 818                                  * the same, we break out of the loop.
 819                                  * Since found isn't set, changed will be
 820                                  * set to 1 below.
 821                                  */
 822                                 for (j = 0; j < old_num_selections; j++) {
 823                                         if (((*dev_select)[i].device_number ==
 824                                               old_dev_select[j].device_number)
 825                                          && ((*dev_select)[i].selected ==
 826                                               old_dev_select[j].selected)){
 827                                                 found = 1;
 828                                                 break;
 829                                         }
 830                                         else if ((*dev_select)[i].device_number
 831                                             == old_dev_select[j].device_number)
 832                                                 break;
 833                                 }
 834                                 if (found == 0)
 835                                         changed = 1;
 836                         }
 837                 }
 838         }
 839         if (old_dev_select != NULL)
 840                 free(old_dev_select);
 841
 842         return(changed);
 843 }
 844
 845 /*
 846  * Comparison routine for qsort() above.  Note that the comparison here is
 847  * backwards -- generally, it should return a value to indicate whether
 848  * arg1 is <, =, or > arg2.  Instead, it returns the opposite.  The reason
 849  * it returns the opposite is so that the selection array will be sorted in
 850  * order of decreasing performance.  We sort on two parameters.  The first
 851  * sort key is whether or not one or the other of the devices in question
 852  * has been selected.  If one of them has, and the other one has not, the
 853  * selected device is automatically more important than the unselected
 854  * device.  If neither device is selected, we judge the devices based upon
 855  * performance.
 856  */
 857 static int
 858 compare_select(const void *arg1, const void *arg2)
 859 {
 860         if ((((const struct device_selection *)arg1)->selected)
 861          && (((const struct device_selection *)arg2)->selected == 0))
 862                 return(-1);
 863         else if ((((const struct device_selection *)arg1)->selected == 0)
 864               && (((const struct device_selection *)arg2)->selected))
 865                 return(1);
 866         else if (((const struct device_selection *)arg2)->bytes <
 867                  ((const struct device_selection *)arg1)->bytes)
 868                 return(-1);
 869         else if (((const struct device_selection *)arg2)->bytes >
 870                  ((const struct device_selection *)arg1)->bytes)
 871                 return(1);
 872         else
 873                 return(0);
 874 }
 875
 876 /*
 877  * Take a string with the general format "arg1,arg2,arg3", and build a
 878  * device matching expression from it.
 879  */
 880 int
 881 buildmatch(const char *match_str, struct devstat_match **matches,
 882            int *num_matches)
 883 {
 884         char *tstr[5];
 885         char **tempstr;
 886         char *matchbuf_orig;    /* strdup of match_str */
 887         char *matchbuf;         /* allow strsep to clobber */
 888         int num_args;
 889         int i, j;
 890         int retval = -1;
 891
 892         /* We can't do much without a string to parse */
 893         if (match_str == NULL) {
 894                 sprintf(devstat_errbuf, "%s: no match expression", __func__);
 895                 return(-1);
 896         }
 897
 898         /*
 899          * Break the (comma delimited) input string out into separate strings.
 900          * strsep is destructive, so copy the string first.
 901          */
 902         matchbuf = matchbuf_orig = strdup(match_str);
 903         if (matchbuf == NULL) {
 904                 sprintf(devstat_errbuf, "%s: out of memory", __func__);
 905                 return(-1);
 906         }
 907         for (tempstr = tstr, num_args  = 0;
 908              (*tempstr = strsep(&matchbuf, ",")) != NULL && (num_args < 5);
 909              num_args++)
 910                 if (**tempstr != '\0')
 911                         if (++tempstr >= &tstr[5])
 912                                 break;
 913
 914         /* The user gave us too many type arguments */
 915         if (num_args > 3) {
 916                 sprintf(devstat_errbuf, "%s: too many type arguments",
 917                         __func__);
 918                 goto cleanup;
 919         }
 920
 921         /*
 922          * Since you can't realloc a pointer that hasn't been malloced
 923          * first, we malloc first and then realloc.
 924          */
 925         if (*num_matches == 0)
 926                 *matches = (struct devstat_match *)malloc(
 927                            sizeof(struct devstat_match));
 928         else
 929                 *matches = (struct devstat_match *)realloc(*matches,
 930                           sizeof(struct devstat_match) * (*num_matches + 1));
 931
 932         /* Make sure the current entry is clear */
 933         bzero(&matches[0][*num_matches], sizeof(struct devstat_match));
 934
 935         /*
 936          * Step through the arguments the user gave us and build a device
 937          * matching expression from them.
 938          */
 939         for (i = 0; i < num_args; i++) {
 940                 char *tempstr2, *tempstr3;
 941
 942                 /*
 943                  * Get rid of leading white space.
 944                  */
 945                 tempstr2 = tstr[i];
 946                 while (isspace(*tempstr2) && (*tempstr2 != '\0'))
 947                         tempstr2++;
 948
 949                 /*
 950                  * Get rid of trailing white space.
 951                  */
 952                 tempstr3 = &tempstr2[strlen(tempstr2) - 1];
 953
 954                 while ((*tempstr3 != '\0') && (tempstr3 > tempstr2)
 955                     && (isspace(*tempstr3))) {
 956                         *tempstr3 = '\0';
 957                         tempstr3--;
 958                 }
 959
 960                 /*
 961                  * Go through the match table comparing the user's
 962                  * arguments to known device types, interfaces, etc.
 963                  */
 964                 for (j = 0; match_table[j].match_str != NULL; j++) {
 965                         /*
 966                          * We do case-insensitive matching, in case someone
 967                          * wants to enter "SCSI" instead of "scsi" or
 968                          * something like that.  Only compare as many
 969                          * characters as are in the string in the match
 970                          * table.  This should help if someone tries to use
 971                          * a super-long match expression.
 972                          */
 973                         if (strncasecmp(tempstr2, match_table[j].match_str,
 974                             strlen(match_table[j].match_str)) == 0) {
 975                                 /*
 976                                  * Make sure the user hasn't specified two
 977                                  * items of the same type, like "da" and
 978                                  * "cd".  One device cannot be both.
 979                                  */
 980                                 if (((*matches)[*num_matches].match_fields &
 981                                     match_table[j].match_field) != 0) {
 982                                         sprintf(devstat_errbuf,
 983                                                 "%s: cannot have more than "
 984                                                 "one match item in a single "
 985                                                 "category", __func__);
 986                                         goto cleanup;
 987                                 }
 988                                 /*
 989                                  * If we've gotten this far, we have a
 990                                  * winner.  Set the appropriate fields in
 991                                  * the match entry.
 992                                  */
 993                                 (*matches)[*num_matches].match_fields |=
 994                                         match_table[j].match_field;
 995                                 (*matches)[*num_matches].device_type |=
 996                                         match_table[j].type;
 997                                 (*matches)[*num_matches].num_match_categories++;
 998                                 break;
 999                         }
1000                 }
1001                 /*
1002                  * We should have found a match in the above for loop.  If
1003                  * not, that means the user entered an invalid device type
1004                  * or interface.
1005                  */
1006                 if ((*matches)[*num_matches].num_match_categories != (i + 1)) {
1007                         snprintf(devstat_errbuf, sizeof(devstat_errbuf),
1008                                 "%s: unknown match item \"%s\"", __func__,
1009                                 tstr[i]);
1010                         goto cleanup;
1011                 }
1012         }
1013
1014         (*num_matches)++;
1015         retval = 0;
1016 cleanup:
1017         free(matchbuf_orig);
1018         return(retval);
1019 }
1020
1021 /*
1022  * Compute a number of device statistics.  Only one field is mandatory, and
1023  * that is "current".  Everything else is optional.  The caller passes in
1024  * pointers to variables to hold the various statistics he desires.  If he
1025  * doesn't want a particular staistic, he should pass in a NULL pointer.
1026  * Return values:
1027  * 0   -- success
1028  * -1  -- failure
1029  */
1030 int
1031 compute_stats(struct devstat *current, struct devstat *previous,
1032               long double etime, u_int64_t *total_bytes,
1033               u_int64_t *total_transfers, u_int64_t *total_blocks,
1034               long double *kb_per_transfer, long double *transfers_per_second,
1035               long double *mb_per_second, long double *blocks_per_second,
1036               long double *ms_per_transaction)
1037 {
1038         u_int64_t totalbytes, totaltransfers, totalblocks;
1039
1040         /*
1041          * current is the only mandatory field.
1042          */
1043         if (current == NULL) {
1044                 sprintf(devstat_errbuf, "%s: current stats structure was NULL",
1045                         __func__);
1046                 return(-1);
1047         }
1048
1049         totalbytes = (current->bytes_written + current->bytes_read) -
1050                      ((previous) ? (previous->bytes_written +
1051                                     previous->bytes_read) : 0);
1052
1053         if (total_bytes)
1054                 *total_bytes = totalbytes;
1055
1056         totaltransfers = (current->num_reads +
1057                           current->num_writes +
1058                           current->num_other) -
1059                          ((previous) ?
1060                           (previous->num_reads +
1061                            previous->num_writes +
1062                            previous->num_other) : 0);
1063         if (total_transfers)
1064                 *total_transfers = totaltransfers;
1065
1066         if (transfers_per_second) {
1067                 if (etime > 0.0) {
1068                         *transfers_per_second = totaltransfers;
1069                         *transfers_per_second /= etime;
1070                 } else
1071                         *transfers_per_second = 0.0;
1072         }
1073
1074         if (kb_per_transfer) {
1075                 *kb_per_transfer = totalbytes;
1076                 *kb_per_transfer /= 1024;
1077                 if (totaltransfers > 0)
1078                         *kb_per_transfer /= totaltransfers;
1079                 else
1080                         *kb_per_transfer = 0.0;
1081         }
1082
1083         if (mb_per_second) {
1084                 *mb_per_second = totalbytes;
1085                 *mb_per_second /= 1024 * 1024;
1086                 if (etime > 0.0)
1087                         *mb_per_second /= etime;
1088                 else
1089                         *mb_per_second = 0.0;
1090         }
1091
1092         totalblocks = totalbytes;
1093         if (current->block_size > 0)
1094                 totalblocks /= current->block_size;
1095         else
1096                 totalblocks /= 512;
1097
1098         if (total_blocks)
1099                 *total_blocks = totalblocks;
1100
1101         if (blocks_per_second) {
1102                 *blocks_per_second = totalblocks;
1103                 if (etime > 0.0)
1104                         *blocks_per_second /= etime;
1105                 else
1106                         *blocks_per_second = 0.0;
1107         }
1108
1109         if (ms_per_transaction) {
1110                 if (totaltransfers > 0) {
1111                         *ms_per_transaction = etime;
1112                         *ms_per_transaction /= totaltransfers;
1113                         *ms_per_transaction *= 1000;
1114                 } else
1115                         *ms_per_transaction = 0.0;
1116         }
1117
1118         return(0);
1119 }
1120
1121 int
1122 compute_stats_read(struct devstat *current, struct devstat *previous,
1123               long double etime, u_int64_t *total_bytes,
1124               u_int64_t *total_transfers, u_int64_t *total_blocks,
1125               long double *kb_per_transfer, long double *transfers_per_second,
1126               long double *mb_per_second, long double *blocks_per_second,
1127               long double *ms_per_transaction)
1128 {
1129         u_int64_t totalbytes, totaltransfers, totalblocks;
1130
1131         /*
1132          * current is the only mandatory field.
1133          */
1134         if (current == NULL) {
1135                 sprintf(devstat_errbuf, "%s: current stats structure was NULL",
1136                         __func__);
1137                 return(-1);
1138         }
1139
1140         totalbytes = current->bytes_read -
1141                      (previous ? previous->bytes_read : 0);
1142
1143         if (total_bytes)
1144                 *total_bytes = totalbytes;
1145
1146         totaltransfers = current->num_reads -
1147                          (previous ? previous->num_reads : 0);
1148         if (total_transfers)
1149                 *total_transfers = totaltransfers;
1150
1151         if (transfers_per_second) {
1152                 if (etime > 0.0) {
1153                         *transfers_per_second = totaltransfers;
1154                         *transfers_per_second /= etime;
1155                 } else
1156                         *transfers_per_second = 0.0;
1157         }
1158
1159         if (kb_per_transfer) {
1160                 *kb_per_transfer = totalbytes;
1161                 *kb_per_transfer /= 1024;
1162                 if (totaltransfers > 0)
1163                         *kb_per_transfer /= totaltransfers;
1164                 else
1165                         *kb_per_transfer = 0.0;
1166         }
1167
1168         if (mb_per_second) {
1169                 *mb_per_second = totalbytes;
1170                 *mb_per_second /= 1024 * 1024;
1171                 if (etime > 0.0)
1172                         *mb_per_second /= etime;
1173                 else
1174                         *mb_per_second = 0.0;
1175         }
1176
1177         totalblocks = totalbytes;
1178         if (current->block_size > 0)
1179                 totalblocks /= current->block_size;
1180         else
1181                 totalblocks /= 512;
1182
1183         if (total_blocks)
1184                 *total_blocks = totalblocks;
1185
1186         if (blocks_per_second) {
1187                 *blocks_per_second = totalblocks;
1188                 if (etime > 0.0)
1189                         *blocks_per_second /= etime;
1190                 else
1191                         *blocks_per_second = 0.0;
1192         }
1193
1194         if (ms_per_transaction) {
1195                 if (totaltransfers > 0) {
1196                         *ms_per_transaction = etime;
1197                         *ms_per_transaction /= totaltransfers;
1198                         *ms_per_transaction *= 1000;
1199                 } else
1200                         *ms_per_transaction = 0.0;
1201         }
1202
1203         return(0);
1204 }
1205
1206 int
1207 compute_stats_write(struct devstat *current, struct devstat *previous,
1208               long double etime, u_int64_t *total_bytes,
1209               u_int64_t *total_transfers, u_int64_t *total_blocks,
1210               long double *kb_per_transfer, long double *transfers_per_second,
1211               long double *mb_per_second, long double *blocks_per_second,
1212               long double *ms_per_transaction)
1213 {
1214         u_int64_t totalbytes, totaltransfers, totalblocks;
1215
1216         /*
1217          * current is the only mandatory field.
1218          */
1219         if (current == NULL) {
1220                 sprintf(devstat_errbuf, "%s: current stats structure was NULL",
1221                         __func__);
1222                 return(-1);
1223         }
1224
1225         totalbytes = current->bytes_written -
1226                      (previous ? previous->bytes_written : 0);
1227
1228         if (total_bytes)
1229                 *total_bytes = totalbytes;
1230
1231         totaltransfers = current->num_writes -
1232                          (previous ? previous->num_writes : 0);
1233         if (total_transfers)
1234                 *total_transfers = totaltransfers;
1235
1236         if (transfers_per_second) {
1237                 if (etime > 0.0) {
1238                         *transfers_per_second = totaltransfers;
1239                         *transfers_per_second /= etime;
1240                 } else
1241                         *transfers_per_second = 0.0;
1242         }
1243
1244         if (kb_per_transfer) {
1245                 *kb_per_transfer = totalbytes;
1246                 *kb_per_transfer /= 1024;
1247                 if (totaltransfers > 0)
1248                         *kb_per_transfer /= totaltransfers;
1249                 else
1250                         *kb_per_transfer = 0.0;
1251         }
1252
1253         if (mb_per_second) {
1254                 *mb_per_second = totalbytes;
1255                 *mb_per_second /= 1024 * 1024;
1256                 if (etime > 0.0)
1257                         *mb_per_second /= etime;
1258                 else
1259                         *mb_per_second = 0.0;
1260         }
1261
1262         totalblocks = totalbytes;
1263         if (current->block_size > 0)
1264                 totalblocks /= current->block_size;
1265         else
1266                 totalblocks /= 512;
1267
1268         if (total_blocks)
1269                 *total_blocks = totalblocks;
1270
1271         if (blocks_per_second) {
1272                 *blocks_per_second = totalblocks;
1273                 if (etime > 0.0)
1274                         *blocks_per_second /= etime;
1275                 else
1276                         *blocks_per_second = 0.0;
1277         }
1278
1279         if (ms_per_transaction) {
1280                 if (totaltransfers > 0) {
1281                         *ms_per_transaction = etime;
1282                         *ms_per_transaction /= totaltransfers;
1283                         *ms_per_transaction *= 1000;
1284                 } else
1285                         *ms_per_transaction = 0.0;
1286         }
1287
1288         return(0);
1289 }
1290
1291 long double
1292 compute_etime(struct timeval cur_time, struct timeval prev_time)
1293 {
1294         struct timeval busy_time;
1295         u_int64_t busy_usec;
1296         long double etime;
1297
1298         timersub(&cur_time, &prev_time, &busy_time);
1299
1300         busy_usec = busy_time.tv_sec;
1301         busy_usec *= 1000000;
1302         busy_usec += busy_time.tv_usec;
1303         etime = busy_usec;
1304         etime /= 1000000;
1305
1306         return(etime);
1307 }