4 files changed, 16 insertions, 16 deletions
diff --git a/runtime/jdwp/jdwp.h b/runtime/jdwp/jdwp.h
index fec0e31..4c17c96 100644
--- a/runtime/jdwp/jdwp.h
+++ b/runtime/jdwp/jdwp.h
@@ -274,7 +274,7 @@ struct JdwpState {
 
  private:
   explicit JdwpState(const JdwpOptions* options);
-  void ProcessRequest(Request& request, ExpandBuf* pReply);
+  size_t ProcessRequest(Request& request, ExpandBuf* pReply);
   bool InvokeInProgress();
   bool IsConnected();
   void SuspendByPolicy(JdwpSuspendPolicy suspend_policy, JDWP::ObjectId thread_self_id)
diff --git a/runtime/jdwp/jdwp_handler.cc b/runtime/jdwp/jdwp_handler.cc
index 5f21098..c2a2b54 100644
--- a/runtime/jdwp/jdwp_handler.cc
+++ b/runtime/jdwp/jdwp_handler.cc
@@ -1659,7 +1659,7 @@ static std::string DescribeCommand(Request& request) {
  *
  * On entry, the JDWP thread is in VMWAIT.
  */
-void JdwpState::ProcessRequest(Request& request, ExpandBuf* pReply) {
+size_t JdwpState::ProcessRequest(Request& request, ExpandBuf* pReply) {
   JdwpError result = ERR_NONE;
 
   if (request.GetCommandSet() != kJDWPDdmCmdSet) {
@@ -1728,14 +1728,11 @@ void JdwpState::ProcessRequest(Request& request, ExpandBuf* pReply) {
    * If we encountered an error, only send the header back.
    */
   uint8_t* replyBuf = expandBufGetBuffer(pReply);
+  size_t replyLength = (result == ERR_NONE) ? expandBufGetLength(pReply) : kJDWPHeaderLen;
+  Set4BE(replyBuf + 0, replyLength);
   Set4BE(replyBuf + 4, request.GetId());
   Set1(replyBuf + 8, kJDWPFlagReply);
   Set2BE(replyBuf + 9, result);
-  if (result == ERR_NONE) {
-    Set4BE(replyBuf + 0, expandBufGetLength(pReply));
-  } else {
-    Set4BE(replyBuf + 0, kJDWPHeaderLen);
-  }
 
   CHECK_GT(expandBufGetLength(pReply), 0U) << GetCommandName(request) << " " << request.GetId();
 
@@ -1757,6 +1754,8 @@ void JdwpState::ProcessRequest(Request& request, ExpandBuf* pReply) {
 
   /* tell the VM that GC is okay again */
   self->TransitionFromRunnableToSuspended(old_state);
+
+  return replyLength;
 }
 
 /*
diff --git a/runtime/jdwp/jdwp_main.cc b/runtime/jdwp/jdwp_main.cc
index 500585d..77c963f 100644
--- a/runtime/jdwp/jdwp_main.cc
+++ b/runtime/jdwp/jdwp_main.cc
@@ -122,11 +122,12 @@ void JdwpNetStateBase::Close() {
 }
 
 /*
- * Write a packet. Grabs a mutex to assure atomicity.
+ * Write a packet of "length" bytes. Grabs a mutex to assure atomicity.
  */
-ssize_t JdwpNetStateBase::WritePacket(ExpandBuf* pReply) {
+ssize_t JdwpNetStateBase::WritePacket(ExpandBuf* pReply, size_t length) {
   MutexLock mu(Thread::Current(), socket_lock_);
-  return TEMP_FAILURE_RETRY(write(clientSock, expandBufGetBuffer(pReply), expandBufGetLength(pReply)));
+  DCHECK_LE(length, expandBufGetLength(pReply));
+  return TEMP_FAILURE_RETRY(write(clientSock, expandBufGetBuffer(pReply), length));
 }
 
 /*
@@ -173,7 +174,7 @@ void JdwpState::SendRequest(ExpandBuf* pReq) {
   }
 
   errno = 0;
-  ssize_t actual = netState->WritePacket(pReq);
+  ssize_t actual = netState->WritePacket(pReq, expandBufGetLength(pReq));
   if (static_cast<size_t>(actual) != expandBufGetLength(pReq)) {
     PLOG(ERROR) << StringPrintf("Failed to send JDWP packet to debugger (%zd of %zu)",
                                 actual, expandBufGetLength(pReq));
@@ -387,8 +388,8 @@ bool JdwpState::HandlePacket() {
   JDWP::Request request(netStateBase->input_buffer_, netStateBase->input_count_);
 
   ExpandBuf* pReply = expandBufAlloc();
-  ProcessRequest(request, pReply);
-  ssize_t cc = netStateBase->WritePacket(pReply);
+  size_t replyLength = ProcessRequest(request, pReply);
+  ssize_t cc = netStateBase->WritePacket(pReply, replyLength);
 
   /*
    * We processed this request and sent its reply. Notify other threads waiting for us they can now
@@ -396,7 +397,7 @@ bool JdwpState::HandlePacket() {
    */
   EndProcessingRequest();
 
-  if (cc != (ssize_t) expandBufGetLength(pReply)) {
+  if (cc != static_cast<ssize_t>(replyLength)) {
     PLOG(ERROR) << "Failed sending reply to debugger";
     expandBufFree(pReply);
     return false;
diff --git a/runtime/jdwp/jdwp_priv.h b/runtime/jdwp/jdwp_priv.h
index 4e6aada..29ad185 100644
--- a/runtime/jdwp/jdwp_priv.h
+++ b/runtime/jdwp/jdwp_priv.h
@@ -69,8 +69,8 @@ class JdwpNetStateBase {
 
   void Close();
 
-  ssize_t WritePacket(ExpandBuf* pReply);
-  ssize_t WriteBufferedPacket(const std::vector<iovec>& iov);
+  ssize_t WritePacket(ExpandBuf* pReply, size_t length) LOCKS_EXCLUDED(socket_lock_);
+  ssize_t WriteBufferedPacket(const std::vector<iovec>& iov) LOCKS_EXCLUDED(socket_lock_);
 
   int clientSock;  // Active connection to debugger.