99 lines
2.4 KiB
C
99 lines
2.4 KiB
C
/*
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* No copyright is claimed. This code is in the public domain; do with
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* it what you wish.
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*
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* Please, don't add this file to libcommon because timers requires
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* -lrt on systems with old libc (and probably also -lpthread for static
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* build).
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*/
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#include <time.h>
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#include <signal.h>
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#include <sys/time.h>
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#include "c.h"
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#include "timer.h"
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/*
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* Note the timeout is used for the first signal, then the signal is send
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* repeatedly in interval ~1% of the original timeout to avoid race in signal
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* handling -- for example you want to use timer to define timeout for a
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* syscall:
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*
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* setup_timer()
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* syscall()
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* cancel_timer()
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*
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* if the timeout is too short than it's possible that the signal is delivered
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* before application enter the syscall function. For this reason timer send
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* the signal repeatedly.
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*
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* The applications need to ensure that they can tolerate multiple signal
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* deliveries.
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*/
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#ifdef HAVE_TIMER_CREATE
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int setup_timer(struct ul_timer *timer,
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struct itimerval *timeout,
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void (*timeout_handler)(int, siginfo_t *, void *))
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{
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time_t sec = timeout->it_value.tv_sec;
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long usec = timeout->it_value.tv_usec;
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struct sigaction sig_a;
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static struct sigevent sig_e = {
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.sigev_notify = SIGEV_SIGNAL,
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.sigev_signo = SIGALRM
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};
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struct itimerspec val = {
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.it_value.tv_sec = sec,
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.it_value.tv_nsec = usec * 1000,
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.it_interval.tv_sec = sec / 100,
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.it_interval.tv_nsec = (sec ? sec % 100 : 1) * 10*1000*1000
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};
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if (sigemptyset(&sig_a.sa_mask))
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return 1;
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sig_a.sa_flags = SA_SIGINFO;
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sig_a.sa_sigaction = timeout_handler;
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if (sigaction(SIGALRM, &sig_a, NULL))
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return 1;
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if (timer_create(CLOCK_MONOTONIC, &sig_e, &timer->t_id))
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return 1;
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if (timer_settime(timer->t_id, 0, &val, NULL))
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return 1;
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return 0;
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}
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void cancel_timer(struct ul_timer *timer)
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{
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timer_delete(timer->t_id);
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}
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#else /* !HAVE_TIMER_CREATE */
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int setup_timer(struct ul_timer *timer,
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struct itimerval *timeout,
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void (*timeout_handler)(int, siginfo_t *, void *))
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{
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struct sigaction sa;
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memset(&sa, 0, sizeof sa);
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memset(timer, 0, sizeof(*timer));
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sa.sa_flags = SA_SIGINFO | SA_RESETHAND;
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sa.sa_sigaction = timeout_handler;
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if (sigaction(SIGALRM, &sa, &timer->old_sa))
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return 1;
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if (setitimer(ITIMER_REAL, timeout, &timer->old_timer) != 0)
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return 1;
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return 0;
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}
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void cancel_timer(struct ul_timer *timer)
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{
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setitimer(ITIMER_REAL, &timer->old_timer, NULL);
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sigaction(SIGALRM, &timer->old_sa, NULL);
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}
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#endif /* !HAVE_TIMER_CREATE */
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