ls -l 구현 중 질문

#define SIZE 256
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <pwd.h>
#include <grp.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
char type(mode_t);
char *perm(mode_t);
 
struct list
{
	char name[SIZE];
	char mode[SIZE];
	char permission[SIZE];
	int nlink;
	char uid[SIZE];
	char gid[SIZE];
	int size;
	char time[SIZE];
 
};
int main(int argc, char **argv)
{
	DIR *dp;
	char *dir;
	struct list *lt;
	struct stat st;
	struct passwd *pa;
	struct group *gr;
	struct time *ti;
	struct dirent *d;
        char array[256][256];
	char path[BUFSIZ+1];
	int i=0;
	int num=0;
	int mal=0; //variable to dynamic allocation;
	if(argc == 1)
		dir=".";
	else
		dir=argv[1];
 
	if((dp=opendir(dir))==NULL)
		perror(dir);
	while((d=readdir(dp))!=NULL)
	{
		lt=(struct list *)malloc(sizeof(struct list)*mal);
		mal++;
	}
 
	rewinddir(dp);
 
	while((d=readdir(dp))!=NULL)
	{
		sprintf(path, "%s/%s", dir, d->d_name);
		if(lstat(path, &st)<0)
			perror(path);
		else
		{	
			strcpy(lt[num].mode, type(st.st_mode));
			strcpy(lt[num].permission, perm(st.st_mode));
			pa = getpwuid(st.st_uid);
			strcpy(lt[num].uid, pa->pw_name);
 
			gr = getgrgid(st.st_gid);
			strcpy(lt[num].gid, gr->gr_name);
 
			lt[num].nlink=st.st_nlink;
			lt[num].size=st.st_size;
 
			ti=ctime(st.st_mtime);
 
 
			strcpy(array[num], d->d_name);
			num++;		
		}	
	}
	for(i=0;i<num;i++)
	{
		printf("%s\n", array[num]);
	}
 
	closedir(dp);
	exit(0);
}
 
 
 
char type(mode_t mode)
{
	if(S_ISREG(mode)) return('-');
	else if(S_ISDIR(mode)) return('d');
	else if(S_ISCHR(mode)) return('c');
	else if(S_ISBLK(mode)) return('b');
	else if(S_ISLNK(mode)) return('l');
	else if(S_ISFIFO(mode)) return('p');
	else if(S_ISSOCK(mode)) return('s');
	else return('0');
 
}
 
char *perm(mode_t mode)
{
	int i;
	static char perms[10] = "----------";
	for(int i=0; i<3; i++)
	{
		if(mode & (S_IRUSR>>i*3))
			perms[i*3]='r';
		else if(mode & (S_IWUSR>>i*3))
			perms[i*3+1]='w';
		else if(mode & (S_IXUSR>>i*3))
			perms[i*3+2]='x';
	}
	return(perms);
}