CODEWITHSUNDEEP
csegmentation-faultmalloc
Jackie
Jackie

Reputation: 153

C - Segmentation fault : 11

Hi I have to do a simulation of disk for my university.

I got 2 file :

tttfs.h :

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

typedef struct _disk disk;
typedef struct _block block;

struct _block{
    uint8_t *unBlock;
};

struct _disk{
    int id;
    block *diskBlock;
};

tfs_create.c :

#include "tttfs.h"

uint8_t little[4];

int tttfs_create(int size, char *name);
void inttolitend(uint32_t x, uint8_t* lit_int);

int main(){
    tttfs_create(7, "disk.tfs");
}

int tttfs_create(int size, char *name){
    FILE *f = NULL;
    if ((f = fopen(name, "wb"))!=NULL)
    {
    disk *d = malloc(sizeof(disk));
    d->diskBlock = malloc(1024);
    d->id = 1;
    int i;
    for(i = 0; i<size; i++){
       printf("%d\n", i);
       d->diskBlock[i].unBlock = malloc(1024); //I got the segmentation fault here
    }
    inttolitend(size, little);
    for(i = 0; i<4; i++){
       d->diskBlock[0].unBlock[i] = little[i];
    }
    for(i = 0; i<size; i++){
       fwrite(&d->diskBlock[i],1024,1,f);
    }
    }
    else
        printf("Erreur\n\n");
    return 0;
}

void inttolitend(uint32_t x, uint8_t* lit_int){
   lit_int[3] = (uint8_t)x / (256*256*256);
   lit_int[2] = (uint8_t)(x % (256*256*256)) / (256*256);
   lit_int[1] = (uint8_t)((x % (256*256*256)) % (256*256)) / 256;
   lit_int[0] = (uint8_t)((x % (256*256*256)) % (256*256)) % 256;
}

I want to write in a file a number of block (here 7), so I do malloc on size of my disk struct and then I do a malloc on diskBlock to make a table d->diskBlock[0].unBlock = malloc(1024); but not for more. how could I do a block[size] with my struct ? (I'm not good in c)

Upvotes: 1

Views: 49

Answers (1)

Haris
Haris

Reputation: 12270

I think you should change this line

d->diskBlock = malloc(1024);

to

d->diskBlock = malloc(sizeof(block) * size);

And, this

d->diskBlock[i].unBlock = malloc(1024);

to

d->diskBlock[i].unBlock = malloc(sizeof(uint8_t) * 4);

Upvotes: 1

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