Improve stability of Linux ProcessMonitor by not using fds for synchronization:

- ProcessMonitor::[Do|Serve]Operation no longer depend on file descriptors!
- removed unused member functions CloseFD and EnableIPC
- add semaphores to signal when an Operation is ready to be processed/complete.

This commit fixes a bug that was identified under stress-testing (i.e. build
LLVM while running tests) that led to LLDB becoming unresponsive because the
read/write operations on file descriptors in ProcessMonitor were not checked.

Other test runner improvement/convenience:
- pickup environment variables LLDB_LINUX_LOG and LLDB_LINUX_LOG_OPTIONS to
  enable (Linux) logging when running the test suite. Example usage:

        $ LLDB_LINUX_LOG="mylog.txt" LLDB_LINUX_LOG_OPTIONS="process thread" python dotest.py

llvm-svn: 190820

1 files changed, 8 insertions, 9 deletions

diff --git a/lldb/source/Plugins/Process/Linux/ProcessMonitor.h b/lldb/source/Plugins/Process/Linux/ProcessMonitor.h
index 2de6bc0737d..4d02e61a10f 100644
--- a/lldb/source/Plugins/Process/Linux/ProcessMonitor.h
+++ b/lldb/source/Plugins/Process/Linux/ProcessMonitor.h
@@ -193,10 +193,15 @@ private:
     lldb::pid_t m_pid;
     int m_terminal_fd;
 
+    // current operation which must be executed on the priviliged thread
+    Operation *m_operation;
+    lldb_private::Mutex m_operation_mutex;
+
+    // semaphores notified when Operation is ready to be processed and when
+    // the operation is complete.
+    sem_t m_operation_pending;
+    sem_t m_operation_done;
 
-    lldb_private::Mutex m_server_mutex;
-    int m_client_fd;
-    int m_server_fd;
 
     struct OperationArgs
     {
@@ -244,9 +249,6 @@ private:
     static bool
     Launch(LaunchArgs *args);
 
-    bool
-    EnableIPC();
-
     struct AttachArgs : OperationArgs
     {
         AttachArgs(ProcessMonitor *monitor,
@@ -309,9 +311,6 @@ private:
     /// Stops the operation thread used to attach/launch a process.
     void
     StopOpThread();
-
-    void
-    CloseFD(int &fd);
 };
 
 #endif // #ifndef liblldb_ProcessMonitor_H_