| /* |
| * Please, don't add this file to libcommon because timers requires |
| * -lrt on systems with old libc (and probably also -lpthread for static |
| * build). |
| */ |
| #include <time.h> |
| #include <signal.h> |
| #include <sys/time.h> |
| |
| #include "c.h" |
| #include "timer.h" |
| |
| /* |
| * Note the timeout is used for the first signal, then the signal is send |
| * repeatedly in interval ~1% of the original timeout to avoid race in signal |
| * handling -- for example you want to use timer to define timeout for a |
| * syscall: |
| * |
| * setup_timer() |
| * syscall() |
| * cancel_timer() |
| * |
| * if the timeout is too short than it's possible that the signal is delivered |
| * before application enter the syscall function. For this reason timer send |
| * the signal repeatedly. |
| * |
| * The applications need to ensure that they can tolerate multiple signal |
| * deliveries. |
| */ |
| int setup_timer(timer_t * t_id, struct itimerval *timeout, |
| void (*timeout_handler)(int, siginfo_t *, void *)) |
| { |
| time_t sec = timeout->it_value.tv_sec; |
| long usec = timeout->it_value.tv_usec; |
| struct sigaction sig_a; |
| static struct sigevent sig_e = { |
| .sigev_notify = SIGEV_SIGNAL, |
| .sigev_signo = SIGALRM |
| }; |
| struct itimerspec val = { |
| .it_value.tv_sec = sec, |
| .it_value.tv_nsec = usec * 1000, |
| .it_interval.tv_sec = sec / 100, |
| .it_interval.tv_nsec = (sec ? sec % 100 : 1) * 10*1000*1000 |
| }; |
| |
| if (sigemptyset(&sig_a.sa_mask)) |
| return 1; |
| |
| sig_a.sa_flags = SA_SIGINFO; |
| sig_a.sa_sigaction = timeout_handler; |
| |
| if (sigaction(SIGALRM, &sig_a, NULL)) |
| return 1; |
| if (timer_create(CLOCK_MONOTONIC, &sig_e, t_id)) |
| return 1; |
| if (timer_settime(*t_id, 0, &val, NULL)) |
| return 1; |
| return 0; |
| } |
| |
| void cancel_timer(timer_t *t_id) |
| { |
| timer_delete(*t_id); |
| } |