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ecore: detect and emit event on system time changed. 

If we have timerfd then we can set a timer with special features
(ABSTIME | CANCELON) to be notified if its offset to monotonic time
change, effectively this will alert us if user called settimeofday()
or similar method to change system time.

This code was inspired by Enlightenment's clock module.
This commit is contained in:
Gustavo Sverzut Barbieri 2013-08-09 00:02:04 -03:00
parent 0a9c78896b
commit ca39ff976e
1 changed files with 72 additions and 0 deletions
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72
src/lib/ecore/ecore_main.c
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@ -127,6 +127,13 @@ epoll_ctl(int epfd EINA_UNUSED,
# endif
#endif /* HAVE_SYS_TIMERFD_H */
#ifndef TFD_TIMER_ABSTIME
# define TFD_TIMER_ABSTIME (1 << 0)
#endif
#ifndef TFD_TIMER_CANCELON_SET
# define TFD_TIMER_CANCELON_SET (1 << 1)
#endif
#ifndef HAVE_TIMERFD_CREATE
static inline int
timerfd_create(int clockid EINA_UNUSED,
@ -763,6 +770,67 @@ static GSourceFuncs ecore_gsource_funcs =
#endif
#ifdef HAVE_SYS_TIMERFD_H
static int realtime_fd = -1;
static void detect_time_changes_start(void);
static Eina_Bool
_realtime_update(void *data EINA_UNUSED, Ecore_Fd_Handler *fdh EINA_UNUSED)
{
char buf[64];
if (read(realtime_fd, buf, sizeof(buf)) >= 0) return EINA_TRUE;
DBG("system clock changed");
ecore_event_add(ECORE_EVENT_SYSTEM_TIMEDATE_CHANGED, NULL, NULL, NULL);
close(realtime_fd);
realtime_fd = -1;
detect_time_changes_start();
return EINA_FALSE;
}
#endif
static void
detect_time_changes_start(void)
{
#ifdef HAVE_SYS_TIMERFD_H
struct itimerspec its;
if (realtime_fd >= 0) return;
realtime_fd = timerfd_create(CLOCK_REALTIME, TFD_NONBLOCK | TFD_CLOEXEC);
if (realtime_fd < 0) return;
memset(&its, 0, sizeof(its));
if (timerfd_settime(realtime_fd,
TFD_TIMER_ABSTIME | TFD_TIMER_CANCELON_SET,
&its, NULL) < 0)
{
WRN("Couldn't arm timerfd to detect clock changes: %s",
strerror(errno));
close(realtime_fd);
realtime_fd = -1;
return;
}
ecore_main_fd_handler_add(realtime_fd, ECORE_FD_READ,
_realtime_update, NULL, NULL, NULL);
#endif
}
static void
detect_time_changes_stop(void)
{
#ifdef HAVE_SYS_TIMERFD_H
if (realtime_fd > 0)
{
close(realtime_fd);
realtime_fd = -1;
}
#endif
}
void
_ecore_main_loop_init(void)
{
@ -818,6 +886,8 @@ _ecore_main_loop_init(void)
CRIT("Failed to attach glib source to default context");
}
#endif
detect_time_changes_start();
}
void
@ -831,6 +901,8 @@ _ecore_main_loop_shutdown(void)
}
#endif
detect_time_changes_stop();
if (epoll_fd >= 0)
{
close(epoll_fd);