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/**
* Copyright (c) 2015, Suresh Sundriyal
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* * 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.
* * Neither the name of the copyright holder nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''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 THE REGENTS OR CONTRIBUTORS 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 "timer.hh"
#include "base/lnav_log.hh"
#include "config.h"
static const struct itimerval DISABLE_TV = {{0, 0}, {0, 0}};
timer::error::error(int err) : e_err(err) {}
timer::interrupt_timer::interrupt_timer(struct timeval t,
sighandler_t_ sighandler = SIG_IGN)
: new_handler(sighandler), new_val((struct itimerval){{0, 0}, t}),
old_val(DISABLE_TV), armed(false)
{
memset(&this->old_handler, 0, sizeof(this->old_handler));
}
int
timer::interrupt_timer::arm_timer()
{
struct sigaction sa;
// Disable the interval timer before setting the handler and arming the
// interval timer or else we will have a race-condition where the timer
// might fire and the appropriate handler might not be set.
if (setitimer(ITIMER_REAL, &DISABLE_TV, &this->old_val) != 0) {
log_error("Unable to disable the timer: %s", strerror(errno));
return -1;
}
memset(&sa, 0, sizeof(sa));
sa.sa_handler = this->new_handler;
if (sigaction(SIGALRM, &sa, &this->old_handler) == -1) {
log_error("Unable to set the signal handler: %s", strerror(errno));
if (setitimer(ITIMER_REAL, &this->old_val, NULL) != 0) {
log_error("Unable to reset the interrupt timer: %s",
strerror(errno));
throw timer::error(errno);
}
return -1;
}
if (setitimer(ITIMER_REAL, &this->new_val, NULL) != 0) {
if (sigaction(SIGALRM, &this->old_handler, NULL) == -1) {
log_error("Unable to reset the signal handler: %s",
strerror(errno));
throw timer::error(errno);
}
log_error("Unable to set the timer: %s", strerror(errno));
return -1;
}
this->armed = true;
return 0;
}
bool
timer::interrupt_timer::is_armed()
{
return this->armed;
}
void
timer::interrupt_timer::disarm_timer()
{
if (this->armed) {
// Disable the interval timer before resetting the handler and rearming
// the previous interval timer or else we will have a race-condition
// where the timer might fire and the appropriate handler might not be
// set.
if (setitimer(ITIMER_REAL, &DISABLE_TV, NULL) != 0) {
log_error("Failed to disable the timer: %s", strerror(errno));
throw timer::error(errno);
}
if (sigaction(SIGALRM, &this->old_handler, NULL) == -1) {
log_error("Failed to reinstall previous SIGALRM handler: %s",
strerror(errno));
throw timer::error(errno);
}
if (setitimer(ITIMER_REAL, &this->old_val, NULL) != 0) {
log_error("Failed to reset the timer to previous value: %s",
strerror(errno));
throw timer::error(errno);
}
this->armed = false;
this->old_val = DISABLE_TV;
memset(&this->old_handler, 0, sizeof(this->old_handler));
}
}
timer::interrupt_timer::~interrupt_timer()
{
this->disarm_timer();
}
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