Hack to filter input devices available to Clone Hero

input-veto.c

#include <sys/types.h>
#include <stdio.h>
#define __USE_GNU
#include <dlfcn.h>
#include <linux/limits.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdbool.h>

static int (*real_openat64)(int, const char*, int, mode_t) = NULL;

static const char* device_dirs[] = {
	"/sys/devices/virtual/misc/uhid",
	"/sys/devices/virtual/input"
};

static const char* allowed_devices[] = {
	"Nintendo Wii Remote Guitar",
};

static bool veto_input_open(int dirfd, const char* name) {
	char namebuf[PATH_MAX] = {0};
	char dirpath[PATH_MAX] = {0};

	snprintf(namebuf, PATH_MAX, "/proc/self/fd/%d", dirfd);
	int res = readlink(namebuf, dirpath, PATH_MAX);

	if (res == -1) return true;
	
	bool dir_found = false;
	for (int i = 0; i < sizeof(device_dirs) / sizeof(char*); i++) {
		if (memcmp(dirpath, device_dirs[i], strlen(device_dirs[i])) == 0) {
			dir_found = true;
			break;
		}
	}
	if (!dir_found)
		return true;
	
	snprintf(namebuf, PATH_MAX, "%s/%s/name", dirpath, name);
	FILE* namefile = fopen(namebuf, "r");
	if (!namefile)
		return true;

	int namelen = fread(namebuf, 1, PATH_MAX, namefile);
	namebuf[namelen - 1] = 0;

	for (int i = 0; i < sizeof(allowed_devices) / sizeof(char*); i++) {
		if (strcmp(namebuf, allowed_devices[i]) == 0)
			return true;
	}

	return false;
}

int openat64(int dirfd, const char* pathname, int flags, mode_t mode) {
	if (!real_openat64) real_openat64 = dlsym(RTLD_NEXT, "openat64");

	bool allowed = true;
	//if (memcmp(pathname, "input", 5) == 0 && pathname[5] != 0)
		allowed = veto_input_open(dirfd, pathname);

	if (allowed) {
		return real_openat64(dirfd, pathname, flags, mode);
	} else {
		errno = EACCES;
		return -1;
	}
}