public
Created

Prints a HID device to stdout

  • Download Gist
printhid.c
C
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <linux/input.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <signal.h>
 
void handler (int sig)
{
printf ("\nexiting...(%d)\n", sig);
exit(0);
}
 
void perror_exit (char *error)
{
perror(error);
handler(9);
}
 
int main (int argc, char *argv[])
{
struct input_event ev[64];
int fd, rd, value, size = sizeof (struct input_event);
char name[256] = "Unknown";
char *device = NULL;
 
//Setup check
if (argv[1] == NULL){
fprintf(stderr, "Please specify (on the command line) the path to the dev event interface device\n");
exit (0);
}
 
if ((getuid ()) != 0)
fprintf (stderr, "You are not root! This may not work...\n");
 
if (argc > 1)
device = argv[1];
 
//Open Device
if ((fd = open (device, O_RDONLY)) == -1) {
fprintf (stderr, "%s is not a vaild device.\n", device);
exit(1);
}
//Print Device Name
ioctl (fd, EVIOCGNAME (sizeof (name)), name);
fprintf (stderr, "Reading From : %s (%s)\n", device, name);
//Stop propagation of the event
ioctl (fd, EVIOCGRAB, 1);
 
while (1) {
if ((rd = read (fd, ev, size * 64)) < size)
perror_exit("read()");
 
value = ev[0].value;
if (value != ' ' && ev[1].value == 1 && ev[1].type == 1){ // Only read the key press event
int val = ev[1].code - 1;
if (val == 27) {
fprintf (stdout, "\n");
}else{
fprintf (stdout, "%d", val);
}
fflush(stdout);
}
}
return 0;
}

Please sign in to comment on this gist.

Something went wrong with that request. Please try again.