kde-lockscreen-suspend-display/xdg/keypressdetector/evdev.c

#include "evdev.h"

#include <errno.h>
#include <linux/input.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>


int block_until_keypress(const char* keyboardPath) {
    int keyboardFd = open(keyboardPath, O_RDONLY);
    if (keyboardFd < 0) {
        return errno;
    }

    int eventSize = sizeof(struct input_event);
    int bytesRead = 0;
    struct input_event events[NUM_EVENTS];

    int readEvents = 1;
    while(readEvents) {
        bytesRead = read(keyboardFd, events, eventSize * NUM_EVENTS);
        if (bytesRead < 0) {
            return errno;
        }

        for(int i = 0; i < (bytesRead / eventSize); ++i) {
            struct input_event event = events[i];
            if(event.type == EV_KEY) {
                if(event.value == 1) {
                    readEvents = 0;
                }
            }
        }
    }

    close(keyboardFd);
    return 0;
}