#define FUSE_USE_VERSION 30

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <pwd.h>

#include <fuse.h>

static int usersfs_getattr(const char *path, struct stat *stbuf)
{
	if (strcmp(path, "/") == 0) {
		stbuf->st_mode = S_IFDIR | 0755;
		stbuf->st_nlink = 2;
	} else {
		struct passwd *pwent = getpwnam(path + 1);
		if (pwent && pwent->pw_dir) {
			stbuf->st_mode = S_IFLNK | 0444;
			stbuf->st_nlink = 1;
		} else {
			return -ENOENT;
		}
	}
	return 0;
}

static int usersfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
                            off_t offset, struct fuse_file_info *fi)
{
	if (strcmp(path, "/") != 0) {
		return -ENOENT;
	}

	(void) offset;
	(void) fi;

	filler(buf, ".", NULL, 0);
	filler(buf, "..", NULL, 0);

	struct passwd *pwent;
	setpwent();
	while (pwent = getpwent()) {
		if ((pwent->pw_uid == 0 || pwent->pw_uid >= 1000) && pwent->pw_name && pwent->pw_dir) {
			filler(buf, pwent->pw_name, NULL, 0);
		}
	}
	setpwent();

}

static int usersfs_readlink(const char *path, char *buf, size_t size)
{
	if (strcmp(path, "/") == 0) {
		return -EINVAL;
	}

	struct passwd *pwent = getpwnam(path + 1);
	if (pwent && pwent->pw_dir) {
		strcpy(buf, pwent->pw_dir);
		return 0;
	} else {
		return -ENOENT;
	}
}

static struct fuse_operations usersfs_oper = {
	.getattr = usersfs_getattr,
    .readdir = usersfs_readdir,
	.readlink = usersfs_readlink
};

int main(int argc, char *argv[])
{
	return fuse_main(argc, argv, &usersfs_oper, NULL);
}