memory_eater2.c

#include <stdio.h>
#include <stdlib.h>

#include <unistd.h>

#define MEMINFO "/proc/meminfo"
#define MEM "/dev/mem"
#define MB 1024 * 1024


// Returns free memory in kB
int get_free_memory(){
	FILE *f;
	char buff[80];

	f = fopen(MEMINFO, "r");
	fscanf(f, "%*s%*s%*s%*s%s", buff); // MemFree: %s
	fclose(f);

	return atoi(buff);
}


int main(int argc, char *argv[]){
	// check permissions
	if (geteuid() != 0){
		fputs("This program needs to run under the root (euid == 0)!\n", stderr);
		return 1;
	}
	
	// check procfs
	if(access(MEMINFO, R_OK) == -1){
		fputs("This program needs procfs (http://en.wikipedia.org/wiki/proc)!\n", stderr);
		return 2;
	}
	
	// check swapoff
	if (system("which swapoff > /dev/null") != 0){
		fputs("This program needs 'swapoff' command!\n", stderr);
		return 3;
	}
	
	// turn off swap
	printf("Turning off swap .. ");
	if (system("swapoff -a") != 0){
		fputs("Oucha, cant turn off swap! :(\n", stderr);
		return 4;
	}
	puts("done.");
	
	// eat free memory
	char *v;
	uint i, amount;
	
	puts("Eating memory:");
	while((amount = get_free_memory()) > 0){
		printf("\tFree memory: %dkB\n", amount);
		
		if ((v = malloc(MB)) != 0)
			for(i = 0; i < MB; i++)
				v[i] = 0xFF;
		else
			break;
	}

	return 0;
}