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