753163e1-3061-4268-9b8f-f16e19e718b9.zip

#include<stdlib.h> #include<stdio.h> #include<unistd.h> #define NUM 0x10 char* chunks[NUM]; unsigned long cookie; #define SIZE 0x100 void init_io(){ setvbuf(stdin, 0, 2, 0); setvbuf(stdout, 0, 2, 0); setvbuf(stderr, 0, 2, 0); int fd = open("/dev/urandom", 0); if(fd == -1){ exit(-1); } read(fd, &cookie, 8); close(fd); } unsigned long get_int(){ unsigned long res; scanf("%ld", &res); return res; } void allocate(){ unsigned long idx; printf("Index: "); idx = get_int(); if(idx >= NUM){ return ; } char* buf = malloc(SIZE); if(buf == NULL){ puts("allocate failed"); return; } chunks[idx] = buf; unsigned long* p = chunks[idx] + SIZE - 8; *p = cookie; puts("Done!"); } void delete(){ unsigned long idx; printf("Index: "); idx = get_int(); if(idx >= NUM || chunks[idx] == NULL){ return ; } unsigned long* p = chunks[idx] + SIZE - 8; if(*p != cookie) return; *p = 0; free(chunks[idx]); } void show(){ unsigned long idx; printf("Index: "); idx = get_int(); if(idx >= NUM || chunks[idx] == NULL){ return ; } unsigned long* p = chunks[idx] + SIZE - 8; if(*p != cookie) return; write(1, "Content: ", strlen("Content: ")); write(1, chunks[idx], SIZE - 8); write(1, "\n", 1); } void edit(){ unsigned long idx; printf("Index: "); idx = get_int(); if(idx >= NUM || chunks[idx] == NULL){ return ; } unsigned long* p = chunks[idx] + SIZE - 8; if(*p != cookie) return; printf("Content: "); read(0, chunks[idx], SIZE); } void menu(){ puts("1. allocate"); puts("2. edit"); puts("3. show"); puts("4. delete"); puts("5. exit"); printf("Your choice: "); } int main(){ init_io(); puts("Made on Ubuntu 18.04"); while(1){ menu(); unsigned long choice = get_int(); switch(choice){ case 1: allocate(); break; case 2: edit(); break; case 3: show(); break; case 4: delete(); break; case 5: exit(0); break; default: puts("Unknown"); break; } } return 0; }