linux-kernel-module-cheat/userland/ioctl.c

/* https://github.com/cirosantilli/linux-kernel-module-cheat#ioctl */

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "../include/ioctl.h"

int main(int argc, char **argv)
{
	char *ioctl_path;
	int fd, request, arg0, arg1, arg_int, ret;
	lkmc_ioctl_struct arg_struct;

	if (argc < 2) {
		puts("Usage: ./prog <ioctl-file> <request> [<arg>...]");
		return EXIT_FAILURE;
	}
	ioctl_path = argv[1];
	request = strtol(argv[2], NULL, 10);
	if (argc > 3) {
		arg0 = strtol(argv[3], NULL, 10);
	}
	if (argc > 4) {
		arg1 = strtol(argv[4], NULL, 10);
	}

	fd = open(ioctl_path, O_RDONLY);
	if (fd == -1) {
		perror("open");
		return EXIT_FAILURE;
	}
	switch (request)
	{
		case 0:
			arg_int = arg0;
			ret = ioctl(fd, LKMC_IOCTL_INC, &arg_int);
			if (ret != -1) {
				printf("%d\n", arg_int);
			}
			break;
		case 1:
			arg_struct.i = arg0;
			arg_struct.j = arg1;
			ret = ioctl(fd, LKMC_IOCTL_INC_DEC, &arg_struct);
			if (ret != -1) {
				printf("%d %d\n", arg_struct.i, arg_struct.j);
			}
			break;
		default:
			puts("error: unknown request");
			return EXIT_FAILURE;
	}
	if (ret == -1) {
		perror("ioctl");
		printf("errno = %d\n", errno);
		return EXIT_FAILURE;
	}
	close(fd);
	return EXIT_SUCCESS;
}