ls 프로그램

//myls.c

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <pwd.h>
#include <grp.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>

#define BUF_SIZE 512

#define mode_l "-l"
#define mode_a "-a"
#define mode_al "-al"
#define mode_nomal "nomal"


char type(mode_t mode);
char* perm(mode_t mode);
void printStat(char* pathname, char* file, struct stat* st);
void ls(char* dir, char* mode);
void ls_nomal(char* dir);
void file_l(char* filename, char* mode);
void file_nomal(char* filename, char* mode);

char path[BUF_SIZE];

int main(int argc, char** argv) {

	char* dir;

	
	
	if (argc == 1) { // myls
		dir = ".";
		ls(dir, mode_nomal);
	}
	else if (argc == 2) { // myls -a/-l/filename/dir
		dir = ".";
		ls(dir, argv[1]);
	}
	else if (argc == 3) { // myls -a/-l/-al filename/dir
		ls(argv[2], argv[1]);

	}
	else {
		printf("입력 error\n");
		return 0;
	}
	exit(0);

}

void file_nomal(char* filename,char *mode) {

	DIR* dp;
	struct dirent* d;
	char dir[BUF_SIZE];
	int set = 1;
	
	memset(dir, 0, BUF_SIZE);
	sprintf(dir, "./%s", filename);

	if ((dp = opendir(dir)) == NULL) {
		memset(dir, 0, BUF_SIZE);
		sprintf(dir, ".");
		if ((dp = opendir(dir)) == NULL)
			perror("dir error");
	}
	

	while ((d = readdir(dp)) != NULL) {
		if (!strcmp(filename, d->d_name)) {
			printf("%10s ", d->d_name);
			set = 0;
		}
	}

	closedir(dp);

	if (set)
		ls_nomal(filename);
	
}

void file_l(char* filename, char *mode) {

	DIR* dp;
	struct dirent* d;
	struct stat st;
	int set = 1;
	char* dir = ".";

	if ((dp = opendir(dir)) == NULL)
		perror("name error");

	while ((d = readdir(dp)) != NULL) {
		if (!strcmp(d->d_name, filename)) {
			sprintf(path, "%s/%s", dir, d->d_name);
			if (lstat(path, &st) < 0)
				perror(path);
			printStat(path, d->d_name, &st);
			putchar('\n');
		}
	}

	closedir(dp);
	
}



void printStat(char* pathname, char* file, struct stat* st) {

	//printf("%5ld ", st->st_blocks);
	printf("%c%s ", type(st->st_mode), perm(st->st_mode));
	printf("%3ld ", st->st_nlink);
	printf("%s %s ", getpwuid(st->st_uid)->pw_name, getgrgid(st->st_gid)->gr_name);
	printf("%9ld ", st->st_size);
	printf("%.12s ", ctime(&st->st_mtime) + 4);
	printf("%s", file);

}

char type(mode_t mode) {

	if (S_ISREG(mode))
		return('-');
	if (S_ISDIR(mode))
		return('d');
	if (S_ISCHR(mode))
		return('c');
	if (S_ISBLK(mode))
		return('b');
	if (S_ISLNK(mode))
		return('l');
	if (S_ISFIFO(mode))
		return('p');
	if (S_ISSOCK(mode))
		return('s');

}

char* perm(mode_t mode) {

	int i;
	static char perms[10];

	strcpy(perms, "---------");

	for (i = 0; i < 3; i++) {
		if (mode & (S_IREAD >> i * 3))
			perms[i * 3] = 'r';
		if (mode & (S_IWRITE >> i * 3))
			perms[i * 3 + 1] = 'w';
		if (mode & (S_IEXEC >> i * 3))
			perms[i * 3 + 2] = 'x';
	}

	return(perms);

}


void ls_nomal(char* dir) {
	DIR* dp;
	struct dirent* d;
	struct stat st;

	if ((dp = opendir(dir)) == NULL)
		perror("name error");

	while ((d = readdir(dp)) != NULL)
		if (strncmp(d->d_name, ".", 1))
			printf("%s\n", d->d_name);

	closedir(dp);

}


void ls(char *dir,char* mode) {

	DIR* dp;
	struct dirent* d;
	struct stat st;
	

	if ((dp = opendir(dir)) == NULL) {
		if (!strcmp(mode, mode_l) || !strcmp(mode, mode_al))
			file_l(dir, mode);
		else
			file_nomal(dir, mode);
	}
	else {

		if (!strcmp(mode, mode_a)) {
			while ((d = readdir(dp)) != NULL)
				printf("%s\n", d->d_name);
		}
		else if (!strcmp(mode, mode_l)) {
			while ((d = readdir(dp)) != NULL) {
				if (strncmp(d->d_name, ".", 1)) { // 숨김파일이 아니면
					sprintf(path, "%s/%s", dir, d->d_name);
					if (lstat(path, &st) < 0)
						perror(path);
					printStat(path, d->d_name, &st);
					putchar('\n');
				}
			}
		}
		else if (!strcmp(mode, mode_al)) {
			while ((d = readdir(dp)) != NULL) {
				sprintf(path, "%s/%s", dir, d->d_name);
				if (lstat(path, &st) < 0)
					perror(path);
				printStat(path, d->d_name, &st);
				putchar('\n');
			}
		}
		else if (!strcmp(mode, mode_nomal)) {
			ls_nomal(dir);
		}
		else
			file_nomal(mode, mode_nomal);
	}

	closedir(dp);

}