Question

I’m trying to make a C program work and I’m getting mad. This is my code simplified to find the error:

#include <stdio.h>
#include <unistd.h>
#include <sqlite3.h>

int main(){
    sqlite3 *conn;
    sqlite3_stmt *res;
    const char *tail, *sqlresult;
    sqlite3_open("cubecat", &conn);
    char buffer,query;
    int id;

    id= 1;
    buffer = 'a';
    if(buffer == 'a') snprintf(&query,100,"SELECT start FROM payloads WHERE id=%d", id);

    printf("%s",&query);
    int error = sqlite3_prepare_v2(conn, &query, 100, &res, &tail);
    printf("%d",error);
}

The error is exactly on “sqlite_prepare_v2” function, because if I comment that line, there’s no Segmentation Fault.

Thank you in advance!

Answer 1

char query;
snprintf(&query,100,"SELECT start FROM payloads WHERE id=%d", id);

This is what’s wrong. query only reserves memory for one character. There’s a reason the 2nd argument of snprintf() specifies the size. This code should be modified like this:

char query[100];
snprintf(query, sizeof(query), "SELECT start FROM payloads WHERE id=%d", id);