Fixed deadlock in Process::WorkerThreadProc.

diff --git a/lib/base/process.cpp b/lib/base/process.cpp
index 3fd771f89aa03e4497c76cb13a835ed8a6a70ea3..6ae7ea268c9f23bf75258f24fa50e3b6111ed9ec 100644 (file)
--- 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;
 
                                {