poll poll

#include <errno.h>
#include <fcntl.h>
#include <malloc.h>
#include <poll.h>
#include <stdatomic.h>
#include <stdint.h>
#include <string.h>

#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <android/sync.h>

int sync_wait(int fd, int timeout)
{
    struct pollfd fds;
    int ret;

    if (fd < 0) {
        errno = EINVAL;
        return -1;
    }

    fds.fd = fd;
    fds.events = POLLIN;

    do {
        ret = poll(&fds, 1, timeout);
        if (ret > 0) {
            if (fds.revents & (POLLERR | POLLNVAL)) {
                errno = EINVAL;
                return -1;
            }
            return 0;
        } else if (ret == 0) {
            errno = ETIME;
            return -1;
        }
    } while (ret == -1 && (errno == EINTR || errno == EAGAIN));

    return ret;
}