CODEWITHSUNDEEP
c++sudohid
Edward Severinsen
Edward Severinsen

Reputation: 101

Open function in C says unable to open device: permission denied

I've been messing with hidraw.h to see what I could do with my USB but when I try to open /dev/hidraw0 it says Unable to open device: Permission denied, I know I could do something like system("sudo open /dev/hidraw0"); But of course it wouldn't have the same effect. Also I'm in Kali Linux. Here's my code: 

/* Linux */
#include <linux/types.h>
#include <linux/input.h>
#include <linux/hidraw.h>

/* Unix */
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

/* C */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <iostream>
using namespace std;

int main() 
{
    int fd;
    int i, res, desc_size = 0;
    char buf[256];
    struct hidraw_report_descriptor rpt_desc;
    struct hidraw_devinfo info;

    fd = open("/dev/hidraw0", O_RDWR);

    if(fd < 0)
    {
        perror("Unable to open device");
        return 1;
    }
    else
    {
        cout << "Something happend!" << endl;
        return 0;
    }

}

Upvotes: 1

Views: 3323

Answers (2)

Keith Thompson
Keith Thompson

Reputation: 263387

Your program doesn't have permission to open /dev/hidraw0. So you need to run it in such a way that it has permission.

The simplest way to do that, as ForceBru's comment suggests, is to run the program itself under sudo. (You can't run just the open function under sudo; open is a function, not a program.)

You might also be able to make the program run with root privileges by setting its setuid flag, using chmod u+s or chmod u+gs.

Consider that the device has the permissions it has for what are presumably good reasons. Be careful.

Upvotes: 1

Jeegar Patel
Jeegar Patel

Reputation: 27230

If possible then first try to give some more permission to that device

sudo chmod 777 /dev/hidraw0

then run you program. if required then also try changing its owner by Chown command.

Upvotes: 0

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