From be09d53501f626e0d0d8d0a1b88a7a7be0a4480d Mon Sep 17 00:00:00 2001
From: randomdan <randomdan@localhost>
Date: Sun, 19 Jan 2014 21:19:32 +0000
Subject: Fix up pipe handling in the muxer and write stderr of muxer command
 into the log

---
 p2pvr/lib/muxer.cpp | 134 +++++++++++++++++++++++++++++-----------------------
 p2pvr/lib/muxer.h   |   7 ++-
 2 files changed, 81 insertions(+), 60 deletions(-)

diff --git a/p2pvr/lib/muxer.cpp b/p2pvr/lib/muxer.cpp
index bd00a8c..25f6b57 100644
--- a/p2pvr/lib/muxer.cpp
+++ b/p2pvr/lib/muxer.cpp
@@ -1,57 +1,19 @@
 #include <pch.hpp>
 #include "muxer.h"
 #include <logger.h>
+#include <misc.h>
 #include <poll.h>
 #include <sys/wait.h>
 #include <boost/algorithm/string/split.hpp>
-
-pid_t
-mpopenrw(const std::vector<std::string> & params, int fds[2])
-{
-	int rpipes[2], wpipes[2];
-	if (pipe(rpipes)) {
-		throw std::runtime_error("Failed to create a pipe");
-	}
-	if (pipe(wpipes)) {
-		throw std::runtime_error("Failed to create another pipe");
-	}
-	pid_t child = fork();
-	switch (child) {
-		case -1: // fail
-			throw std::runtime_error("Failed to fork");
-		default: // parent
-			close(wpipes[0]);
-			close(rpipes[1]);
-			fds[0] = wpipes[1];
-			fds[1] = rpipes[0];
-			break;
-		case 0: // in child
-			close(wpipes[1]);
-			close(rpipes[0]);
-			dup2(wpipes[0], 0);
-			dup2(rpipes[1], 1);
-			for (int n = 3; n < 1024; n += 1) {
-				close(n);
-			}
-			char * buf[100];
-			char ** w = &buf[0];
-			BOOST_FOREACH(const auto & p, params) {
-				*w++ = strdup(p.c_str());
-			}
-			*w = NULL;
-			execv(buf[0], buf);
-			abort();
-			break;
-	}
-	return child;
-}
+#include <boost/algorithm/string/classification.hpp>
 
 Muxer::Muxer(const P2PVR::RawDataClientPrx & t, const std::string & cmd) :
 	target(t)
 {
 	std::vector<std::string> params;
 	boost::algorithm::split(params, cmd, isspace, boost::algorithm::token_compress_on);
-	muxerPid = mpopenrw(params, fds);
+	muxerPid = popenrwe(params, fds);
+	Logger()->messagebf(LOG_INFO, "Muxer::%p started with command '%s'", this, cmd);
 }
 
 Muxer::~Muxer()
@@ -61,26 +23,61 @@ Muxer::~Muxer()
 	while (waitpid(muxerPid, &status, WNOHANG) == 0) {
 		ReadMuxerAndSend(5);
 	}
+	Logger()->messagebf(LOG_INFO, "Muxer::%p finished with status %d", this, status);
 	close(fds[1]);
 }
 
 bool
 Muxer::NewData(const P2PVR::Data & data, const Ice::Current &)
 {
-	std::lock_guard<std::mutex> g(lock);
-	ReadMuxerAndSend(0);
-	if (write(fds[0], &data.front(), data.size()) < 1) {
+	if (ReadWaiting())
 		return true;
+	{
+		std::lock_guard<std::mutex> g(wlock);
+		if (write(fds[0], &data.front(), data.size()) < (int)data.size()) {
+			return true;
+		}
+	}
+	return ReadAvailable();
+}
+
+bool
+Muxer::ReadWaiting() const
+{
+	std::lock_guard<std::mutex> g(rlock);
+	pollfd fd = { fds[0], POLLOUT, 0 };
+	while (true) {
+		auto p = poll(&fd, 1, 0);
+		if (p < 0) {
+			// error
+			return true;
+		}
+		else if (p == 0) {
+			// write would block
+			if (ReadMuxerAndSend(1)) return true;
+		}
+		else {
+			// write would not block
+			if (ReadMuxerAndSend(0)) return true;
+			break;
+		}
 	}
+	return false;
+}
+
+bool
+Muxer::ReadAvailable() const
+{
+	std::lock_guard<std::mutex> g(rlock);
 	return ReadMuxerAndSend(0);
 }
 
 bool
 Muxer::ReadMuxerAndSend(int waitTime) const
 {
-	pollfd fd = { fds[1], POLLIN, 0 };
+	pollfd fd[2] = { { fds[1], POLLIN, 0 }, { fds[2], POLLIN, 0 } };
 	while (true) {
-		auto p = poll(&fd, 1, waitTime);
+		auto p = poll(fd, 2, waitTime);
 		if (p < 0) {
 			// error
 			return true;
@@ -89,19 +86,40 @@ Muxer::ReadMuxerAndSend(int waitTime) const
 			// all ok
 			return false;
 		}
-		else if (p > 0) {
-			P2PVR::Data buf(BUFSIZ);
-			auto len = read(fds[1], &buf.front(), buf.size());
-			if (len == 0) {
-				// ok, proc exit
-				return true;
+		else {
+			if (fd[0].revents & POLLIN) {
+				P2PVR::Data buf(BUFSIZ);
+				auto len = read(fds[1], &buf.front(), buf.size());
+				if (len == 0) {
+					// ok, proc exit
+					return true;
+				}
+				if (len < 0) {
+					// error
+					return true;
+				}
+				buf.resize(len);
+				target->NewData(buf);
 			}
-			if (len < 0) {
-				// error
-				return true;
+			if (fd[1].revents & POLLIN) {
+				P2PVR::Data buf(BUFSIZ);
+				auto len = read(fds[2], &buf.front(), buf.size());
+				if (len == 0) {
+					// ok, proc exit
+					return true;
+				}
+				if (len < 0) {
+					// error
+					return true;
+				}
+				buf.resize(len);
+				std::vector<std::string> lines;
+				boost::algorithm::split(lines, buf, boost::algorithm::is_any_of("\r\n\f"), boost::algorithm::token_compress_on);
+				BOOST_FOREACH(const auto & line, lines) {
+					if (line.empty()) continue;
+					Logger()->messagebf(LOG_INFO, "Muxer::%p > %s", this, line);
+				}
 			}
-			buf.resize(len);
-			target->NewData(buf);
 		}
 	}
 }
diff --git a/p2pvr/lib/muxer.h b/p2pvr/lib/muxer.h
index 118b1da..e4789cf 100644
--- a/p2pvr/lib/muxer.h
+++ b/p2pvr/lib/muxer.h
@@ -12,11 +12,14 @@ class Muxer : public P2PVR::RawDataClient {
 		bool NewData(const P2PVR::Data &, const Ice::Current &);
 
 	private:
+		bool ReadWaiting() const;
+		bool ReadAvailable() const;
 		bool ReadMuxerAndSend(int wait) const;
 		const P2PVR::RawDataClientPrx target;
-		int fds[2];
+		int fds[3];
 		pid_t muxerPid;
-		std::mutex lock;
+		mutable std::mutex wlock;
+		mutable std::mutex rlock;
 };
 
 #endif
-- 
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