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#include <linux/uinput.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <stdbool.h>
#include <signal.h>
bool should_stop = false;
void sigint_handler(int _value)
{
(void) _value;
should_stop = true;
printf("SIGINT handled\n");
}
void emit(int fd, int type, int code, int val)
{
struct input_event ie;
ie.type = type;
ie.code = code;
ie.value = val;
/* timestamp values below are ignored */
ie.time.tv_sec = 0;
ie.time.tv_usec = 0;
write(fd, &ie, sizeof(ie));
}
int main(int argc, char *argv[])
{
if (argc < 2) {
fprintf(stderr, "Error: No input device specified\n");
exit(1);
}
const char *input_path = argv[1];
int ifd = open(input_path, O_RDONLY);
if (ifd == -1) {
fprintf(stderr, "\"%s\": ", input_path);
perror("open");
exit(1);
}
int ofd = open("/dev/uinput", O_WRONLY);
if (ofd == -1) {
fprintf(stderr, "\"/dev/uinput\": ");
perror("open");
exit(1);
}
signal(SIGINT, sigint_handler);
/*
* The ioctls below will enable the device that is about to be
* created, to pass key events, in this case the space key.
*/
ioctl(ofd, UI_SET_EVBIT, EV_KEY);
ioctl(ofd, UI_SET_KEYBIT, KEY_SPACE);
struct uinput_setup usetup;
memset(&usetup, 0, sizeof(usetup));
usetup.id.bustype = BUS_USB;
usetup.id.vendor = 0x1234; /* sample vendor */
usetup.id.product = 0x5678; /* sample product */
strcpy(usetup.name, "Example device");
ioctl(ofd, UI_DEV_SETUP, &usetup);
ioctl(ofd, UI_DEV_CREATE);
/*
* On UI_DEV_CREATE the kernel will create the device node for this
* device. We are inserting a pause here so that userspace has time
* to detect, initialize the new device, and can start listening to
* the event, otherwise it will not notice the event we are about
* to send. This pause is only needed in our example code!
*/
sleep(1);
while (!should_stop) {
struct input_event ev;
ssize_t ret = read(ifd, &ev, sizeof(ev));
switch (ev.type) {
case EV_KEY:
printf("EV_KEY, code=%u, value=%d\n", ev.code, ev.value);
break;
case EV_ABS:
/*
* d-pad is EV_ABS
* left-right: code ABS_HAT0X, left=-1, right=1
* down-up: code ABS_HAT0Y, up=-1, down=1
*/
if (ev.code == ABS_HAT0X || ev.code == ABS_HAT0Y) {
printf("type=%u, code=%u, value=%d\n", ev.type, ev.code, ev.value);
}
break;
case EV_SYN:
break;
default:
printf("type=%u, code=%u, value=%d\n", ev.type, ev.code, ev.value);
break;
}
}
/* Key press, report the event, send key release, and report again */
emit(ofd, EV_KEY, KEY_SPACE, 1);
emit(ofd, EV_SYN, SYN_REPORT, 0);
emit(ofd, EV_KEY, KEY_SPACE, 0);
emit(ofd, EV_SYN, SYN_REPORT, 0);
/*
* Give userspace some time to read the events before we destroy the
* device with UI_DEV_DESTOY.
*/
sleep(1);
ioctl(ofd, UI_DEV_DESTROY);
close(ofd);
return 0;
}
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