/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos-sUDqSbJrdHQHWmgEVkV9KA@public.gmane.org>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.

  gcc -Wall `pkg-config fuse --cflags --libs` hang_on_statfs.c -o hang_on_statfs
*/

#define FUSE_USE_VERSION 26

#include <sys/statvfs.h>
#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>

static const char *hello_str = "Hello World!\n";
static const char *hello_path = "/hello";

static int hangtime = 10;

static int hello_getattr(const char *path, struct stat *stbuf)
{
        int res = 0;

        memset(stbuf, 0, sizeof(struct stat));
        if (strcmp(path, "/") == 0) {
                stbuf->st_mode = S_IFDIR | 0755;
                stbuf->st_nlink = 2;
        } else if (strcmp(path, hello_path) == 0) {
                stbuf->st_mode = S_IFREG | 0444;
                stbuf->st_nlink = 1;
                stbuf->st_size = strlen(hello_str);
        } else
                res = -ENOENT;

        return res;
}

static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
                         off_t offset, struct fuse_file_info *fi)
{
        (void) offset;
        (void) fi;

        if (strcmp(path, "/") != 0)
                return -ENOENT;

        filler(buf, ".", NULL, 0);
        filler(buf, "..", NULL, 0);
        filler(buf, hello_path + 1, NULL, 0);

        return 0;
}

static int hello_open(const char *path, struct fuse_file_info *fi)
{
        if (strcmp(path, hello_path) != 0)
                return -ENOENT;

        if ((fi->flags & 3) != O_RDONLY)
                return -EACCES;

        return 0;
}

static int hello_read(const char *path, char *buf, size_t size, off_t offset,
                      struct fuse_file_info *fi)
{
        size_t len;
        (void) fi;
        if(strcmp(path, hello_path) != 0)
                return -ENOENT;

        len = strlen(hello_str);
        if (offset < len) {
                if (offset + size > len)
                        size = len - offset;
                memcpy(buf, hello_str + offset, size);
        } else
                size = 0;

        return size;
}

static int hello_statfs(const char *path, struct statvfs *stbuf)
{
    sleep(hangtime);
    stbuf->f_bsize = 1024;
    stbuf->f_frsize = 512;
    stbuf->f_blocks = 4;
    stbuf->f_bfree = 0;
    stbuf->f_bavail = 0;
    stbuf->f_files = 1;
    stbuf->f_ffree = 0;
    stbuf->f_favail = 0;

    return 0;
}

static struct fuse_operations hello_oper = {
        .getattr	= hello_getattr,
        .statfs         = hello_statfs,
        .readdir	= hello_readdir,
        .open		= hello_open,
        .read		= hello_read,
};

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