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/* libhw/host_alarmclock.c - <libhw/generic/alarmclock.h> implementation for POSIX hosts
*
* Copyright (C) 2024 Luke T. Shumaker <lukeshu@lukeshu.com>
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#include <assert.h>
#include <errno.h>
#include <error.h>
#include <signal.h>
#include <time.h>
#include <libcr/coroutine.h>
#include <libmisc/vcall.h>
#define IMPLEMENTATION_FOR_LIBHW_GENERIC_ALARMCLOCK_H YES
#include <libhw/generic/alarmclock.h>
#include "host_sigrt.h"
/* Types **********************************************************************/
struct hostclock {
implements_alarmclock;
bool initialized;
clockid_t clock_id;
timer_t timer_id;
struct alarmclock_trigger *queue;
};
/* Globals ********************************************************************/
static uint64_t hostclock_get_time_ns(implements_alarmclock *self);
static bool hostclock_add_trigger(implements_alarmclock *self,
struct alarmclock_trigger *trigger,
uint64_t fire_at_ns,
void (*cb)(void *),
void *cb_arg);
static void hostclock_del_trigger(implements_alarmclock *self,
struct alarmclock_trigger *trigger);
static struct alarmclock_vtable hostclock_vtable = {
.get_time_ns = hostclock_get_time_ns,
.add_trigger = hostclock_add_trigger,
.del_trigger = hostclock_del_trigger,
};
static struct hostclock clock_monotonic = {
.vtable = &hostclock_vtable,
.clock_id = CLOCK_MONOTONIC,
};
implements_alarmclock *bootclock = &clock_monotonic;
/* Main implementation ********************************************************/
#define UNUSED(name) /* name __attribute__ ((unused)) */
static uint64_t hostclock_get_time_ns(implements_alarmclock *_alarmclock) {
struct hostclock *alarmclock =
VCALL_SELF(struct hostclock, implements_alarmclock, _alarmclock);
assert(alarmclock);
struct timespec ts;
if (clock_gettime(alarmclock->clock_id, &ts) != 0)
error(1, errno, "clock_gettime(%d)", (int)alarmclock->clock_id);
return ns_from_host_ns_time(ts);
}
static void hostclock_handle_sig_alarm(int UNUSED(sig), siginfo_t *info, void *UNUSED(ucontext)) {
struct hostclock *alarmclock = info->si_value.sival_ptr;
assert(alarmclock);
while (alarmclock->queue &&
alarmclock->queue->fire_at_ns <= hostclock_get_time_ns(alarmclock)) {
struct alarmclock_trigger *trigger = alarmclock->queue;
trigger->cb(trigger->cb_arg);
alarmclock->queue = trigger->next;
trigger->alarmclock = NULL;
trigger->next = NULL;
trigger->prev = NULL;
}
if (alarmclock->queue) {
struct itimerspec alarmspec = {
.it_value = ns_to_host_ns_time(alarmclock->queue->fire_at_ns),
.it_interval = {0},
};
if (timer_settime(alarmclock->timer_id, TIMER_ABSTIME, &alarmspec, NULL) != 0)
error(1, errno, "timer_settime");
}
}
static bool hostclock_add_trigger(implements_alarmclock *_alarmclock,
struct alarmclock_trigger *trigger,
uint64_t fire_at_ns,
void (*cb)(void *),
void *cb_arg) {
struct hostclock *alarmclock =
VCALL_SELF(struct hostclock, implements_alarmclock, _alarmclock);
assert(alarmclock);
assert(trigger);
assert(fire_at_ns);
assert(cb);
trigger->alarmclock = alarmclock;
trigger->fire_at_ns = fire_at_ns;
trigger->cb = cb;
trigger->cb_arg = cb_arg;
cr_disable_interrupts();
struct alarmclock_trigger **dst = &alarmclock->queue;
while (*dst && fire_at_ns >= (*dst)->fire_at_ns)
dst = &(*dst)->next;
trigger->next = *dst;
trigger->prev = *dst ? (*dst)->prev : NULL;
if (*dst)
(*dst)->prev = trigger;
*dst = trigger;
if (!alarmclock->initialized) {
struct sigevent how_to_notify = {
.sigev_notify = SIGEV_SIGNAL,
.sigev_signo = host_sigrt_alloc(),
.sigev_value = {
.sival_ptr = alarmclock,
},
};
struct sigaction action = {
.sa_flags = SA_SIGINFO,
.sa_sigaction = hostclock_handle_sig_alarm,
};
if (sigaction(how_to_notify.sigev_signo, &action, NULL) != 0)
error(1, errno, "sigaction");
if (timer_create(alarmclock->clock_id, &how_to_notify, &alarmclock->timer_id) != 0)
error(1, errno, "timer_create(%d)", (int)alarmclock->clock_id);
alarmclock->initialized = true;
}
if (alarmclock->queue == trigger) {
struct itimerspec alarmspec = {
.it_value = ns_to_host_ns_time(trigger->fire_at_ns),
.it_interval = {0},
};
if (timer_settime(alarmclock->timer_id, TIMER_ABSTIME, &alarmspec, NULL) != 0)
error(1, errno, "timer_settime");
}
cr_enable_interrupts();
return false;
}
static void hostclock_del_trigger(implements_alarmclock *_alarmclock,
struct alarmclock_trigger *trigger) {
struct hostclock *alarmclock =
VCALL_SELF(struct hostclock, implements_alarmclock, _alarmclock);
assert(alarmclock);
assert(trigger);
cr_disable_interrupts();
if (trigger->alarmclock == alarmclock) {
if (!trigger->prev)
alarmclock->queue = trigger->next;
else
trigger->prev->next = trigger->next;
if (trigger->next)
trigger->next->prev = trigger->prev;
trigger->alarmclock = NULL;
trigger->prev = NULL;
trigger->next = NULL;
}
cr_enable_interrupts();
}
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