From 19398159e1f0e2b12456cf0d5116b756237a088c Mon Sep 17 00:00:00 2001
From: Martin Stein <martin.stein@genode-labs.com>
Date: Wed, 19 Dec 2012 15:49:44 +0100
Subject: [PATCH] base-hw: use Genode::memcpy in base/ipc.cc

Ref #583
---
 base-hw/include/base/native_types.h | 14 ++----
 base-hw/src/base/ipc.cc             | 77 ++++++++++-------------------
 2 files changed, 28 insertions(+), 63 deletions(-)

diff --git a/base-hw/include/base/native_types.h b/base-hw/include/base/native_types.h
index e411a0edcd..832e3accf8 100644
--- a/base-hw/include/base/native_types.h
+++ b/base-hw/include/base/native_types.h
@@ -86,25 +86,17 @@ namespace Genode
 	struct Native_utcb
 	{
 		/* UTCB payload */
-		union {
-			char     bytes[1<<MIN_MAPPING_SIZE_LOG2];
-			umword_t words[sizeof(bytes)/sizeof(umword_t)];
-		};
-
-		/**
-		 * Get pointer to a specific word within the UTCB
-		 */
-		umword_t * word(unsigned const index) { return &words[index]; }
+		char payload[1<<MIN_MAPPING_SIZE_LOG2];
 
 		/**
 		 * Get the base of the UTCB
 		 */
-		void * base() { return (void *)bytes; }
+		void * base() { return payload; }
 
 		/**
 		 * Get the UTCB size
 		 */
-		size_t size() { return sizeof(bytes); }
+		size_t size() { return sizeof(payload); }
 	};
 
 	struct Cap_dst_policy
diff --git a/base-hw/src/base/ipc.cc b/base-hw/src/base/ipc.cc
index ad2af7668a..d9df7595a1 100644
--- a/base-hw/src/base/ipc.cc
+++ b/base-hw/src/base/ipc.cc
@@ -38,65 +38,40 @@ enum
  ***************/
 
 /**
- * Translate byte size 's' to size in words
+ * Limit message size to the size of UTCB and message buffer
  */
-static size_t size_in_words(size_t const s) {
-	return (s + sizeof(size_t) - 1) / sizeof(size_t); }
+void limit_msg_size(Msgbuf_base * const msgbuf, Native_utcb * const utcb,
+                    size_t & size)
+{
+	if (size > utcb->size() || size > msgbuf->size()) {
+		kernel_log() << __PRETTY_FUNCTION__ << ": truncate message\n";
+		size = utcb->size() < msgbuf->size() ? utcb->size() : msgbuf->size();
+	}
+}
 
 
 /**
  * Copy message payload to message buffer
  */
-static void copy_utcb_to_msgbuf(Msgbuf_base * const receive_buffer,
-                                size_t const message_size)
+static void utcb_to_msgbuf(Msgbuf_base * const msgbuf, size_t size)
 {
-	/* log data that is received via IPC */
-	enum { VERBOSE = 0 };
-
-	/* get pointers and message attributes */
-	Native_utcb * const utcb          = Thread_base::myself()->utcb();
-	unsigned * const    msgbuf        = (unsigned *)receive_buffer->buf;
-	size_t const        message_wsize = size_in_words(message_size);
-
-	/* assertions, avoid 'printf' in here, it may lead to infinite recursion */
-	if (message_wsize > size_in_words(utcb->size()))
-	{
-		kernel_log() << __PRETTY_FUNCTION__ << ": Oversized message\n";
-		while (1) ;
-	}
-	/* fill message buffer with message */
-	for (unsigned i=0; i < message_wsize; i++)
-		msgbuf[i] = *utcb->word(i);
+	Native_utcb * const utcb = Thread_base::myself()->utcb();
+	limit_msg_size(msgbuf, utcb, size);
+	memcpy(msgbuf->buf, utcb->base(), size);
 }
 
 
 /**
  * Copy message payload to the UTCB
  */
-static void copy_msgbuf_to_utcb(Msgbuf_base * const send_buffer,
-                                size_t const message_size,
-                                unsigned const local_name)
+static void msgbuf_to_utcb(Msgbuf_base * const msgbuf, size_t size,
+                           unsigned const local_name)
 {
-	/* log data that is send via IPC */
-	enum { VERBOSE = 0 };
-
-	/* get pointers and message attributes */
-	Native_utcb * const utcb          = Thread_base::myself()->utcb();
-	unsigned * const    msgbuf        = (unsigned *)send_buffer->buf;
-	size_t const        message_wsize = size_in_words(message_size);
-
-	/* assertions, avoid 'printf' in here, it may lead to infinite recursion */
-	if (message_wsize > size_in_words(utcb->size()))
-	{
-		kernel_log() << __PRETTY_FUNCTION__ << ": Oversized message\n";
-		while (1) ;
-	}
-	/* address message to an object that the targeted thread knows */
-	*utcb->word(0) = local_name;
-
-	/* write message payload */
-	for (unsigned i = 1; i < message_wsize; i++)
-		*utcb->word(i) = msgbuf[i];
+	Native_utcb * const utcb = Thread_base::myself()->utcb();
+	*(unsigned *)utcb->base() = local_name;
+	size += sizeof(local_name);
+	limit_msg_size(msgbuf, utcb, size);
+	memcpy((unsigned *)utcb->base() + 1, (unsigned *)msgbuf->buf + 1, size);
 }
 
 
@@ -144,10 +119,9 @@ void Ipc_client::_call()
 	using namespace Kernel;
 
 	/* send request and receive reply */
-	copy_msgbuf_to_utcb(_snd_msg, _write_offset,
-	                    Ipc_ostream::_dst.local_name());
+	msgbuf_to_utcb(_snd_msg, _write_offset, Ipc_ostream::_dst.local_name());
 	size_t const s = request_and_wait(Ipc_ostream::_dst.dst(), _write_offset);
-	copy_utcb_to_msgbuf(_rcv_msg, s);
+	utcb_to_msgbuf(_rcv_msg, s);
 
 	/* reset unmarshaller */
 	_write_offset = _read_offset = RPC_OBJECT_ID_SIZE;
@@ -187,7 +161,7 @@ void Ipc_server::_prepare_next_reply_wait()
 void Ipc_server::_wait()
 {
 	/* receive next request */
-	copy_utcb_to_msgbuf(_rcv_msg, Kernel::wait_for_request());
+	utcb_to_msgbuf(_rcv_msg, Kernel::wait_for_request());
 
 	/* update server state */
 	_prepare_next_reply_wait();
@@ -206,9 +180,8 @@ void Ipc_server::_reply_wait()
 		return;
 	}
 	/* send reply and receive next request */
-	copy_msgbuf_to_utcb(_snd_msg, _write_offset,
-	                    Ipc_ostream::_dst.local_name());
-	copy_utcb_to_msgbuf(_rcv_msg, Kernel::reply(_write_offset, 1));
+	msgbuf_to_utcb(_snd_msg, _write_offset, Ipc_ostream::_dst.local_name());
+	utcb_to_msgbuf(_rcv_msg, Kernel::reply(_write_offset, 1));
 
 	/* update server state */
 	_prepare_next_reply_wait();