더블포인터 질문드려요

//구조체 선언 부분
#define BUF_SIZE 2500
typedef struct cmd_{
    char *id;
    char *action;
    char *pipe_id;
    char *command;
}cmd;
 
int main (int argc, char **argv){
//error:don't put configuration file
  if (argc <= 1)
    {
      fprintf (stderr, "configuration file must specified\n");
      return -1;
    }
 
    char *fileName=argv[1];
    char *str=(char*)malloc(sizeof(char)*BUF_SIZE);//buffer that save one command line
    FILE *fp;
    int cmd_count=0;//line number variable
 
      if((fp=fopen(fileName,"r"))==NULL){
        fprintf (stderr, "failed to load config file %s \n", fileName);
        return -1;
    }
 
    while(!feof(fp)){
        cmd_count++;
        fgets(str,BUF_SIZE,fp);
 
        if((str[0]!='#')&&(str[0]!='\n')){
            int i=0,invalid_cmd=0,err_result=0;
            err_result=check_err(str);
            if(err_result==1)
                fprintf (stderr, "invalid format in line%d ,ignored \n", cmd_count);
            else{
                printf("%s",str);
//cmd 구조체를 넘기는 부분
cmd *newCmd;
                changeToStruct(str,&newCmd);
                printf("  id=%s action=%s pipe_id=%s ",newCmd->id,newCmd->action,newCmd->pipe_id);
                printf("command=%s\n",newCmd->command);
            }
 
        }
    }
 
    free(str);
    fclose(fp);
  return 0;
}
//str을 구조체로 변환하는 부분
void changeToStruct(char *str,cmd**dst){//temporary void  original cmd    
    cmd newCmd;
    char *buf=str;
    char **bufSection=(char**)malloc(sizeof(char*)*4);
    int i=0,j=0;
//구분자를 기준으로 하여 str을 나눈 다음 bufSection[j]에 넣는 부분
    for(;j<3;j++){
        bufSection[j]=(char*)malloc(sizeof(char)*BUF_SIZE);
        while(buf[i]==' ')
            i++;
        if(buf[i]==':'){
            strcpy(bufSection[j],"no");
            i++;
        }
        else{
            strcpy(bufSection[j],strtok(buf,":"));
            i=strlen(bufSection[j])+1;//1->delim
        }
        buf=&buf[i];
        i=0;
    }
//여기부터 문제입니다ㅠㅠ
    *dst=(cmd*)calloc(sizeof(cmd),sizeof(char));
 
    strncpy((*dst)->id,bufSection[0],strlen(bufSection[0]));
    strncpy((*dst)->action,bufSection[1],strlen(bufSection[1]));
    strncpy((*dst)->pipe_id,bufSection[2],strlen(bufSection[2]));
    while(buf[i]==' ')
        i++;
    if(buf[i+1]=='\0')
        strncpy((*dst)->command,"no",strlen("no"));
    else
        strncpy((*dst)->command,buf,strlen(buf));
 
    for(j=0;j<3;j++)
        free(bufSection[j]);
    free(bufSection);    
    return;
}