ls/ls.c

#define _POSIX_C_SOURCE 200809L
#include <sys/stat.h>
#include <sys/types.h>

#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#ifndef PATH_MAX
#define PATH_MAX 4096
#endif

void ls_ent(const char *path);
void do_regfile(const char *path, const struct stat *sb);
void do_dir(const char *path, const struct stat *sb);
void do_symlink(const char *path, const struct stat *sb);
void do_blockdev(const char *path, const struct stat *sb);
void do_char(const char *path, const struct stat *sb);
void do_fifo(const char *path, const struct stat *sb);
void do_socket(const char *path, const struct stat *sb);
void do_unknown(const char *path, const struct stat *sb);

int
main(int argc, char *argv[])
{
	int i;
	if (argc == 1) {
		ls_ent(".");
	} else {
		for (i = 1; i < argc; i++) {
			if (argv[i][0] == '-') {
				/* argparsing */
			} else {
				ls_ent(argv[i]);
			}
		}
	}
	return 0;
}

void
ls_ent(const char *path)
{
	struct stat sb;
	if (lstat(path, &sb) == -1) {
		err(1, "Failed to stat %s", path);
	}
	if (S_ISREG(sb.st_mode)) {
		do_regfile(path, &sb);
	} else if (S_ISDIR(sb.st_mode)) {
		do_dir(path, &sb);
	} else if (S_ISLNK(sb.st_mode)) {
		do_symlink(path, &sb);
	} else if (S_ISCHR(sb.st_mode)) {
		do_char(path, &sb);
	} else if (S_ISFIFO(sb.st_mode)) {
		do_fifo(path, &sb);
	} else if (S_ISSOCK(sb.st_mode)) {
		do_socket(path, &sb);
	} else {
		do_unknown(path, &sb);
	}
}

void
do_regfile(const char *path, const struct stat *sb)
{
	(void)sb;
	printf("reg: %s\n", path);
}

void
do_dir(const char *path, const struct stat *sb)
{
	DIR *d;
	struct dirent *dir;
	char full_path[PATH_MAX];

	(void)sb;
	d = opendir(path);
	if (!d) {
		err(1, "Failed to open dir: %s", path);
	}
	printf("dir: %s\n", path);
	while ((dir = readdir(d))) {
		/* avoids infinite recursion :( */
		if (strcmp(dir->d_name, ".") == 0 || strcmp(dir->d_name, "..") == 0) {
			continue;
		}
		snprintf(full_path, sizeof(full_path), "%s/%s", path, dir->d_name);
		ls_ent(full_path);
	}
	closedir(d);
}

void
do_symlink(const char *path, const struct stat *sb)
{
	(void)sb;
	printf("sym: %s\n", path);
}

void
do_blockdev(const char *path, const struct stat *sb)
{
	(void)sb;
	printf("blk: %s\n", path);
}

void
do_char(const char *path, const struct stat *sb)
{
	(void)sb;
	printf("char: %s\n", path);
}

void
do_fifo(const char *path, const struct stat *sb)
{
	(void)sb;
	printf("fifo: %s\n", path);
}

void
do_socket(const char *path, const struct stat *sb)
{
	(void)sb;
	printf("sock: %s\n", path);
}

void
do_unknown(const char *path, const struct stat *sb)
{
	(void)sb;
	printf("wtf: %s\n", path);
}