mergerfs/libfuse/example/null.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>

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

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

#define FUSE_USE_VERSION 26

#include <fuse.h>
#include <string.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>

static int null_getattr(const char *path, struct stat *stbuf)
{
	if(strcmp(path, "/") != 0)
		return -ENOENT;

	stbuf->st_mode = S_IFREG | 0644;
	stbuf->st_nlink = 1;
	stbuf->st_uid = getuid();
	stbuf->st_gid = getgid();
	stbuf->st_size = (1ULL << 32); /* 4G */
	stbuf->st_blocks = 0;
	stbuf->st_atime = stbuf->st_mtime = stbuf->st_ctime = time(NULL);

	return 0;
}

static int null_truncate(const char *path, off_t size)
{
	(void) size;

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

	return 0;
}

static int null_open(const char *path, struct fuse_file_info *fi)
{
	(void) fi;

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

	return 0;
}

static int null_read(const char *path, char *buf, size_t size,
		     off_t offset, struct fuse_file_info *fi)
{
	(void) buf;
	(void) offset;
	(void) fi;

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

	if (offset >= (1ULL << 32))
		return 0;

	return size;
}

static int null_write(const char *path, const char *buf, size_t size,
		      off_t offset, struct fuse_file_info *fi)
{
	(void) buf;
	(void) offset;
	(void) fi;

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

	return size;
}

static struct fuse_operations null_oper = {
	.getattr	= null_getattr,
	.truncate	= null_truncate,
	.open		= null_open,
	.read		= null_read,
	.write		= null_write,
};

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