stream: add a stream class abstracting BSD sockets

Currently only synchronous operation is supported, but this will be extended
with asynchronous methods using the new watcher.

src/libstrongswan/networking/streams/stream.c

@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2013 Martin Willi
+ * Copyright (C) 2013 revosec AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "stream.h"
+
+#include <errno.h>
+#include <unistd.h>
+
+typedef struct private_stream_t private_stream_t;
+
+/**
+ * Private data of an stream_t object.
+ */
+struct private_stream_t {
+
+	/**
+	 * Public stream_t interface.
+	 */
+	stream_t public;
+
+	/**
+	 * Underlying socket
+	 */
+	int fd;
+};
+
+METHOD(stream_t, read_, ssize_t,
+	private_stream_t *this, void *buf, size_t len, bool block)
+{
+	while (TRUE)
+	{
+		ssize_t ret;
+
+		if (block)
+		{
+			ret = read(this->fd, buf, len);
+		}
+		else
+		{
+			ret = recv(this->fd, buf, len, MSG_DONTWAIT);
+			if (ret == -1 && errno == EAGAIN)
+			{
+				/* unify EGAIN and EWOULDBLOCK */
+				errno = EWOULDBLOCK;
+			}
+		}
+		if (ret == -1 && errno == EINTR)
+		{	/* interrupted, try again */
+			continue;
+		}
+		return ret;
+	}
+}
+
+METHOD(stream_t, write_, ssize_t,
+	private_stream_t *this, void *buf, size_t len, bool block)
+{
+	ssize_t ret;
+
+	while (TRUE)
+	{
+		if (block)
+		{
+			ret = write(this->fd, buf, len);
+		}
+		else
+		{
+			ret = send(this->fd, buf, len, MSG_DONTWAIT);
+			if (ret == -1 && errno == EAGAIN)
+			{
+				/* unify EGAIN and EWOULDBLOCK */
+				errno = EWOULDBLOCK;
+			}
+		}
+		if (ret == -1 && errno == EINTR)
+		{	/* interrupted, try again */
+			continue;
+		}
+		return ret;
+	}
+}
+
+METHOD(stream_t, destroy, void,
+	private_stream_t *this)
+{
+	close(this->fd);
+	free(this);
+}
+
+/**
+ * See header
+ */
+stream_t *stream_create_from_fd(int fd)
+{
+	private_stream_t *this;
+
+	INIT(this,
+		.public = {
+			.read = _read_,
+			.write = _write_,
+			.destroy = _destroy,
+		},
+		.fd = fd,
+	);
+
+	return &this->public;
+}