From aa2322abbbf877ca59eb14bc77375c098ed2d15d Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gunnar.beutner@netways.de>
Date: Sun, 10 Feb 2013 21:53:08 +0100
Subject: [PATCH] Fixed deadlock in Process::WorkerThreadProc.

---
 lib/base/process.cpp | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/lib/base/process.cpp b/lib/base/process.cpp
index 3fd771f89..6ae7ea268 100644
--- a/lib/base/process.cpp
+++ b/lib/base/process.cpp
@@ -136,7 +136,9 @@ void Process::WorkerThreadProc(int taskFd)
 		int nfds = 0;
 
 		FD_ZERO(&readfds);
-		FD_SET(taskFd, &readfds);
+
+		if (tasks.size() < MaxTasksPerThread)
+			FD_SET(taskFd, &readfds);
 
 		if (taskFd > nfds)
 			nfds = taskFd;
@@ -149,23 +151,36 @@ void Process::WorkerThreadProc(int taskFd)
 			FD_SET(fd, &readfds);
 		}
 
-		timeval tv;
-		tv.tv_sec = 1;
-		tv.tv_usec = 0;
-		select(nfds + 1, &readfds, NULL, NULL, &tv);
+		int rc = select(nfds + 1, &readfds, NULL, NULL, NULL);
+
+		if (rc < 0 && errno != EINTR)
+			BOOST_THROW_EXCEPTION(PosixException("select() failed.", errno));
+
+		if (rc == 0)
+			continue;
+
 #else /* _MSC_VER */
 		Utility::Sleep(1);
 #endif /* _MSC_VER */
 
 #ifndef _MSC_VER
 		if (FD_ISSET(taskFd, &readfds)) {
-			/* clear pipe */
-			char buffer[512];
-			int rc = read(taskFd, buffer, sizeof(buffer));
-			assert(rc >= 1);
+#endif /* _MSC_VER */
+			/* Figure out how many tasks we'd ideally want. */
+			int tasknum = MaxTasksPerThread - tasks.size();
+
+#ifndef _MSC_VER
+			/* Read one byte for every task we take from the pending tasks list. */
+			char buffer[MaxTasksPerThread];
+			tasknum = read(taskFd, &buffer, tasknum);
+
+			if (tasknum < 0)
+				BOOST_THROW_EXCEPTION(PosixException("read() failed.", errno));
+
+			assert(tasknum >= 1);
 #endif /* _MSC_VER */
 
-			while (tasks.size() < MaxTasksPerThread) {
+			for (int i = 0; i < tasknum; i++) {
 				Process::Ptr task;
 
 				{