micro-utils/coreutils/ls.c

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

unsigned int a_flag;
unsigned int l_flag;

void PrintPerm(struct stat sb) {
	printf("%c", (S_ISDIR(sb.st_mode)) ? 'd' : '-');
	printf("%c%c%c", (sb.st_mode & S_IRUSR) ? 'r' : '-', (sb.st_mode & S_IWUSR) ? 'w' : '-', (sb.st_mode & S_IXUSR) ? 'x' : '-');
	printf("%c%c%c", (sb.st_mode & S_IRGRP) ? 'r' : '-', (sb.st_mode & S_IWGRP) ? 'w' : '-', (sb.st_mode & S_IXGRP) ? 'x' : '-');
	printf("%c%c%c", (sb.st_mode & S_IROTH) ? 'r' : '-', (sb.st_mode & S_IWOTH) ? 'w' : '-', (sb.st_mode & S_IXOTH) ? 'x' : '-');
}

char *fileflag(const char *path) {
	struct stat sb;
	if (stat(path, &sb)) {
		fprintf(stderr, "ls: unable to stat %s: %s\n", path, strerror(errno));
		return " ";
	}

	if (S_ISDIR(sb.st_mode))
		return "/";

	else if ((sb.st_mode & S_IXUSR) || (sb.st_mode & S_IXGRP) || (sb.st_mode & S_IXOTH))
		return "*";

	else
		return " ";
}

void PrintInfo(struct stat sb, const char *filename) {
	/* Permissions */
	PrintPerm(sb);

	/* Date */
	struct tm *tm = localtime(&sb.st_mtime);

	char date[14];
	if (strftime(date, sizeof(date), "%b %d %H:%M", tm) == 0) {
		fprintf(stderr, "ls: strftime()\n");
		return;
	}

	/* Group and user name */
	struct passwd *pw = getpwuid(sb.st_uid);
	struct group *gr = getgrgid(sb.st_gid);

	printf("  %s  %s  %jd  %s  %s%s\n", (pw != 0) ? pw->pw_name : "nobody", (gr != 0) ? gr->gr_name : "nobody", (uintmax_t)sb.st_size, date, filename, fileflag(filename));
}

int list(const char *path, int label) {
	struct stat sb;
	if (lstat(path, &sb)) {
		fprintf(stderr, "ls: unable to stat %s: %s\n", path, strerror(errno));
		return 1;
	}

	/* If its file */
	if (!S_ISDIR(sb.st_mode)) {
		if (l_flag)
			PrintInfo(sb, path);

		else
			puts(path);

		return 0;
	}

	/* Make label */
	if (label)
		printf("\n%s: \n", path);

	if (chdir(path)) {
		fprintf(stderr, "ls: %s: %s\n", path, strerror(errno));
		return 1;
	}

	/* Open and print dir */
	DIR *dp = opendir(".");
	if (dp == NULL)
		return 1;

	struct dirent *ep;
	while ((ep = readdir(dp)) != NULL) {
		if (ep->d_name[0] == '.' && !a_flag)
			continue;

		if (l_flag) {
			if (stat(ep->d_name, &sb) == -1) {
				fprintf(stderr, "ls: lstat()\n");
				return 1;
			}

			PrintInfo(sb, ep->d_name);
		}

		else
			printf("%s%s  ", ep->d_name, fileflag(ep->d_name));

	}

	closedir(dp);
	printf("\n");
	return 0;
}



int main(const int argc, const char **argv) {
	int i;
	for (i = 1; i < argc; i++) {
		if (argv[i][0] != '-')
			break;

		else if (!strcmp(argv[i], "-a"))
			a_flag = 1;

		else if (!strcmp(argv[i], "-l"))
			l_flag = 1;

		else if (!strcmp(argv[i], "--help")) {
			printf("ls [-a show hidden files] [-l use a long listing format] [Path]\n");
			return 0;
		}
	}

	if (i == argc)
		return list(".", 0);

	if (i == argc - 1)
		return list(argv[i], 0);

	else
		for (int i = 1; i < argc; i++)
			if (list(argv[i], 1))
				return 1;

	return 0;
}