futex.c

#include <clod/sys/futex.h>
#include <linux/time.h>
#include <linux/errno.h>
#include "syscall.h"
 
enum clod_futex_error clod_futex_wait(const int *ptr, const int expected, int64_t timeout_us) {
    struct timespec ts;
    ts.tv_sec = timeout_us / 1000000;
    ts.tv_nsec = (timeout_us - ts.tv_sec * 1000000) * 1000;
    const long res = syscall(__NR_futex, (long)ptr, __NR_futex_wait, expected, (long)&ts);
    if (res < 0) {
        if (-res == ETIMEDOUT) return CLOD_FUTEX_OK;
        if (-res == EAGAIN) return CLOD_FUTEX_OK;
        if (-res == EINTR) return CLOD_FUTEX_INTERRUPT;
        return CLOD_FUTEX_INVALID;
    }
    return CLOD_FUTEX_OK;
}
 
enum clod_futex_error clod_futex_wake_one(const int *ptr) {
    const long res = syscall(__NR_futex, (long)ptr, __NR_futex_wake, 1);
    if (res < 0) {
        return CLOD_FUTEX_INVALID;
    }
    return CLOD_FUTEX_OK;
}
 
enum clod_futex_error clod_futex_wake_all(const int *ptr) {
    const long res = syscall(__NR_futex, (long)ptr, __NR_futex_wake, (long)INT_MAX);
    if (res < 0) {
        return CLOD_FUTEX_INVALID;
    }
    return CLOD_FUTEX_OK;
}