/*  FUSE: Filesystem in Userspace  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>  This program can be distributed under the terms of the GNU LGPLv2.  See the file COPYING.LIB*/#include "fuse_lowlevel.h"#include "fuse_kernel.h"#include "fuse_i.h"#include <stdio.h>#include <errno.h>#include <unistd.h>#include <assert.h>static int fuse_kern_chan_receive(struct fuse_chan **chp, char *buf,				  size_t size){	struct fuse_chan *ch = *chp;	int err;	ssize_t res;	struct fuse_session *se = fuse_chan_session(ch);	assert(se != NULL);restart:	res = read(fuse_chan_fd(ch), buf, size);	err = errno;	if (fuse_session_exited(se))		return 0;	if (res == -1) {		/* ENOENT means the operation was interrupted, it's safe		   to restart */		if (err == ENOENT)			goto restart;		if (err == ENODEV) {			fuse_session_exit(se);			return 0;		}		/* Errors occuring during normal operation: EINTR (read		   interrupted), EAGAIN (nonblocking I/O), ENODEV (filesystem		   umounted) */		if (err != EINTR && err != EAGAIN)			perror("fuse: reading device");		return -err;	}	if ((size_t) res < sizeof(struct fuse_in_header)) {		fprintf(stderr, "short read on fuse device\n");		return -EIO;	}	return res;}static int fuse_kern_chan_send(struct fuse_chan *ch, const struct iovec iov[],			       size_t count){	if (iov) {		ssize_t res = writev(fuse_chan_fd(ch), iov, count);		int err = errno;		if (res == -1) {			struct fuse_session *se = fuse_chan_session(ch);			assert(se != NULL);			/* ENOENT means the operation was interrupted */			if (!fuse_session_exited(se) && err != ENOENT)				perror("fuse: writing device");			return -err;		}	}	return 0;}static void fuse_kern_chan_destroy(struct fuse_chan *ch){	close(fuse_chan_fd(ch));}#define MIN_BUFSIZE 0x21000struct fuse_chan *fuse_kern_chan_new(int fd){	struct fuse_chan_ops op = {		.receive = fuse_kern_chan_receive,		.send = fuse_kern_chan_send,		.destroy = fuse_kern_chan_destroy,	};	size_t bufsize = getpagesize() + 0x1000;	bufsize = bufsize < MIN_BUFSIZE ? MIN_BUFSIZE : bufsize;	return fuse_chan_new(&op, fd, bufsize, NULL);}