comm: ignore SIGPIPE

This prevents client and server from being sent a SIGPIPE (and
terminating) when the other side unexpectedly closes the connection.
It's way easier to handle this condition when checking the write()
return value, than to do anything smart in a SIGPIPE handler.  More
details:
<http://stackoverflow.com/questions/108183/how-to-prevent-sigpipes-or-handle-them-properly>

Change-Id: I1da5bf5ef79c8b7b00ede976e96ed4f1c560049d

src/core/comm/SocketComm.cc

@@ -1,10 +1,18 @@
 #include <string>
 #include <errno.h>
+#include <signal.h>
 
 #include "SocketComm.hpp"
 
 namespace fail {
 
+void SocketComm::init()
+{
+	// It's usually much easier to handle the error on write(), than to do
+	// anything intelligent in a SIGPIPE handler.
+	signal(SIGPIPE, SIG_IGN);
+}
+
 bool SocketComm::sendMsg(int sockfd, google::protobuf::Message& msg)
 {
 #ifdef USE_SIZE_PREFIX

src/core/comm/SocketComm.hpp

@@ -21,6 +21,10 @@ namespace fail {
 
 class SocketComm {
 public:
+	/**
+	 * This allows us to ignore SIGPIPE.
+	 */
+	static void init();
 	/**
 	 * Send Protobuf-generated message
 	 * @param sockfd open socket descriptor to write to

src/core/cpn/JobServer.hpp

@@ -7,6 +7,7 @@
 #include "util/SynchronizedMap.hpp"
 #include "config/FailConfig.hpp"
 #include "comm/FailControlMessage.pb.h"
+#include "comm/SocketComm.hpp"
 
 #include <list>
 #include <ctime>
@@ -81,6 +82,7 @@ public:
 	JobServer(int port = SERVER_COMM_TCP_PORT) : m_port(port), m_finish(false), m_noMoreExps(false),
 		m_maxThreads(128), m_threadtimeout(0), m_undoneJobs(SERVER_OUT_QUEUE_SIZE)
 	{
+		SocketComm::init();
 		m_runid = std::time(0);
 #ifndef __puma
 		m_serverThread = new boost::thread(&JobServer::run, this); // run operator()() in a thread.

src/core/efw/JobClient.cc

@@ -1,4 +1,5 @@
 #include "JobClient.hpp"
+#include "comm/SocketComm.hpp"
 
 using namespace std;
 
@@ -6,6 +7,7 @@ namespace fail {
 
 JobClient::JobClient(const std::string& server, int port)
 {
+	SocketComm::init();
 	m_server_port = port;
 	m_server = server;
 	m_server_ent = gethostbyname(m_server.c_str());