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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include "statcommon.h"
#include <stdarg.h>
#include <signal.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
extern char *cmdname;
extern int caught_cont;
/*PRINTFLIKE2*/
void
fail(int do_perror, char *message, ...)
{
va_list args;
int save_errno = errno;
va_start(args, message);
(void) fprintf(stderr, "%s: ", cmdname);
(void) vfprintf(stderr, message, args);
va_end(args);
if (do_perror)
(void) fprintf(stderr, ": %s", strerror(save_errno));
(void) fprintf(stderr, "\n");
exit(2);
}
/*
* Sleep until *wakeup + interval, keeping cadence where desired
*
* *wakeup - The time we last wanted to wake up. Updated.
* interval - We want to sleep until *wakeup + interval
* forever - Running for infinite periods, so cadence not important
* *caught_cont - Global set by signal handler if we got a SIGCONT
*/
void
sleep_until(hrtime_t *wakeup, hrtime_t interval, int forever,
int *caught_cont)
{
hrtime_t now, pause, pause_left;
struct timespec pause_tv;
int status;
now = gethrtime();
pause = *wakeup + interval - now;
if (pause <= 0 || pause < (interval / 4))
if (forever || *caught_cont) {
/* Reset our cadence (see comment below) */
*wakeup = now + interval;
pause = interval;
} else {
/*
* If we got here, then the time between the
* output we just did, and the scheduled time
* for the next output is < 1/4 of our requested
* interval AND the number of intervals has been
* requested AND we have never caught a SIGCONT
* (so we have never been suspended). In this
* case, we'll try to stay to the desired
* cadence, and we will pause for 1/2 the normal
* interval this time.
*/
pause = interval / 2;
*wakeup += interval;
}
else
*wakeup += interval;
if (pause < 1000)
/* Near enough */
return;
/* Now do the actual sleep */
pause_left = pause;
do {
pause_tv.tv_sec = pause_left / NANOSEC;
pause_tv.tv_nsec = pause_left % NANOSEC;
status = nanosleep(&pause_tv, (struct timespec *)NULL);
if (status < 0)
if (errno == EINTR) {
now = gethrtime();
pause_left = *wakeup - now;
if (pause_left < 1000)
/* Near enough */
return;
} else {
fail(1, "nanosleep failed");
}
} while (status != 0);
}
/*
* Signal handler - so we can be aware of SIGCONT
*/
void
cont_handler(int sig_number)
{
/* Re-set the signal handler */
(void) signal(sig_number, cont_handler);
caught_cont = 1;
}
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