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/*
* Copyright (c) 2006
* Protium Computing, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Protium Computing, Inc.
* 4. The name of Protium Computing, Inc. may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY PROTIUM COMPUTING ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL PROTIUM COMPUTING BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <sys/syslog.h>
#include <sys/param.h>
struct watch_table {
char *wt_path;
int wt_status;
int wt_reads;
int wt_writes;
#define WT_INVALID 0
#define WT_VALID 1
#define WT_CHECK 2
} iowt[] = {
{ "/sys/block/hda/stat", WT_CHECK, 0, 0},
{ "/sys/block/hdb/stat", WT_CHECK, 0, 0},
{ "/sys/block/hdc/stat", WT_CHECK, 0, 0},
{ "/sys/block/hdd/stat", WT_CHECK, 0, 0},
{ NULL, WT_INVALID, -1, -1}
};
/*
* disk_activity() returns back the total number of read and writes done
* by the devices listed in the io watch table since the last call to
* disk_activity. The number of reads and writes are determined by
* opening and reading each of the valid files listed in the io watch
* table.The number of reads and writes are stored in the io watch table so
* that the next call to this routine can compare the current number of read
* and writes to those stored in the io watch table. The difference for
* each device is summed in the activity variable. The routine lazy
* evaluates the existance of the devices in the table.
*
* For the storcenter, we are only concerned with internal drives.
*
* The wt_path element must point at a diskstat file in the sysfs filesystem.
* File format can be found at: /usr/src/linux/Documentation/iostats.txt
* For this routine:
* nr, nw - number read and writes
* nmr, nmw - number of merged reads and writes
* nsr, nsw - number of the sectors read and written
* tr, tw - time spent reading and writing
* nio - raw number of ios
* tio, wtio - time spent and weighted time spent doing io
*/
int
disk_activity()
{
int activity = 0;
char mesg[256];
int rc, nr, nmr, nsr, tr, nw, nmw, nsw, tw, nio, tio, wtio;
FILE *f;
struct stat st;
struct watch_table *w;
for (w = iowt; w->wt_path; w++) {
/*
* If status ids set to check, do the lazy existence
* evaluation. If stat fails set to invalid. Don't
* worry about perms here.
*/
if ((w->wt_status == WT_CHECK) &&
(stat(w->wt_path, &st) < 0)) {
sprintf(mesg, "%s not available", w->wt_path);
syslog(LOG_INFO, mesg);
w->wt_status = WT_INVALID;
}
/*
* Short circuit the loop if invalid.
*/
if (w->wt_status == WT_INVALID)
continue;
/*
* If it can't be opened rdonly, set to invalid
*/
if ((f = fopen(w->wt_path, "r")) < 0) {
sprintf(mesg, "Unable to open %s, no longer watching",
w->wt_path);
syslog(LOG_INFO, mesg);
w->wt_status = WT_INVALID;
continue;
}
rc = fscanf(f, "%d %d %d %d %d %d %d %d %d %d %d",
&nr, &nmr, &nsr, &tr,
&nw, &nmw, &nsw, &tw,
&nio, &tio, &wtio);
fclose(f);
if (rc != 11) {
sprintf(mesg, "Unable to read %s", w->wt_path);
syslog(LOG_INFO, mesg);
continue;
}
/*
* If we haven't seen any activity on this device before
* then just save the values and go on. This, although
* not strictly necessary, prevents the initial call to
* disk_activity returning back the base set io activity.
* Remember it takes two calls to get a true difference.
*/
if ((w->wt_reads == 0) && (w->wt_writes == 0)) {
w->wt_reads = nr;
w->wt_writes = nw;
continue;
}
activity += (nr - w->wt_reads);
activity += (nw - w->wt_writes);
w->wt_reads = nr;
w->wt_writes = nw;
/*
printf("%s: %d %d %d %d %d %d %d %d %d %d %d\n",
w->wt_path,
nr, nmr, nsr, tr,
nw, nmw, nsw, tw,
nio, tio, wtio);
*/
}
return(activity);
}
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