1 files changed, 95 insertions, 0 deletions

diff --git a/fuse/fuse_kern_chan.c b/fuse/fuse_kern_chan.c
new file mode 100644
index 000000000..03291c361
--- /dev/null
+++ b/fuse/fuse_kern_chan.c
@@ -0,0 +1,95 @@
+/*
+  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 0x21000
+
+struct 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);
+}