A quick hack that allows using LD_PRELOAD for a speedhack

speedhack.cpp

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>

typedef int (*go)(struct timeval *tv, struct timezone *tz);

static int t = 0;
static int M = 100;
static int started = 0;

void* input_thread(void*){
	while (getchar()){
		if (t){
			printf("Speedhack disabled");
			t=0;
		} else {
			printf("Speedhack enabled");
			t=1;
		}
	}
	return NULL;
}


static long last_usec;
static long skipped_usec=0;

extern "C" int gettimeofday(struct timeval *tv, struct timezone *tz)
{
    // Testing purposes:
    go gettimeofday_orig;
    int val;
    gettimeofday_orig=(go)dlsym(RTLD_NEXT,"gettimeofday");
    if (!started)
    {
		pthread_t t;
		pthread_create(&t, NULL, input_thread, NULL);

		started=1;
    }

    val = gettimeofday_orig(tv,tz);

	long usec = tv->tv_sec*1000000 + tv->tv_usec;
	long delta_usec = usec - last_usec;
	last_usec = usec;

	if (t){
		skipped_usec+= delta_usec*M;
	}

	tv->tv_usec += skipped_usec;

	tv->tv_sec += skipped_usec / 1000000;
	tv->tv_usec += skipped_usec % 1000000;

    return val;
}