<rdar://problem/10760649>

Fixed another double file descriptor close issue that could occur when destroying a ProcessGDBRemote() object. There was a race which was detected by our fd_interposing library:

error: /Applications/Xcode.app/Contents/MacOS/Xcode (pid=55222): close (fd=60) resulted in EBADF:
0   libFDInterposing.dylib              0x00000001082be8ca close$__interposed__ + 666
1   LLDB                                0x00000001194fde91 lldb_private::ConnectionFileDescriptor::Close(int&, lldb_private::Error*) + 97
2   LLDB                                0x00000001194fddcd lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Error*) + 143
3   LLDB                                0x00000001194fe249 lldb_private::ConnectionFileDescriptor::Read(void*, unsigned long, unsigned int, lldb::ConnectionStatus&, lldb_private::Error*) + 835
4   LLDB                                0x00000001194fc320 lldb_private::Communication::Read(void*, unsigned long, unsigned int, lldb::ConnectionStatus&, lldb_private::Error*) + 634
5   LLDB                                0x000000011959c7f4 GDBRemoteCommunication::WaitForPacketWithTimeoutMicroSecondsNoLock(StringExtractorGDBRemote&, unsigned int) + 228
6   LLDB                                0x000000011959c6b5 GDBRemoteCommunication::WaitForPacketWithTimeoutMicroSeconds(StringExtractorGDBRemote&, unsigned int) + 49
7   LLDB                                0x0000000119629a71 GDBRemoteCommunicationClient::SendContinuePacketAndWaitForResponse(ProcessGDBRemote*, char const*, unsigned long, StringExtractorGDBRemote&) + 509
8   LLDB                                0x00000001195a4076 ProcessGDBRemote::AsyncThread(void*) + 514
9   LLDB                                0x0000000119568094 ThreadCreateTrampoline(void*) + 91
10  libsystem_c.dylib                   0x00007fff8ca028bf _pthread_start + 335
11  libsystem_c.dylib                   0x00007fff8ca05b75 thread_start + 13

fd=60 was previously closed with this event:
pid=55222: close (fd=60) => 0
0   libFDInterposing.dylib              0x00000001082be870 close$__interposed__ + 576
1   LLDB                                0x00000001194fde91 lldb_private::ConnectionFileDescriptor::Close(int&, lldb_private::Error*) + 97
2   LLDB                                0x00000001194fddcd lldb_private::ConnectionFileDescriptor::Disconnect(lldb_private::Error*) + 143
3   LLDB                                0x00000001194fbf00 lldb_private::Communication::Disconnect(lldb_private::Error*) + 92
4   LLDB                                0x00000001195a2a77 ProcessGDBRemote::StopAsyncThread() + 89
5   LLDB                                0x00000001195a2bf6 ProcessGDBRemote::DoDestroy() + 310
6   LLDB                                0x00000001195f938d lldb_private::Process::Destroy() + 85
7   LLDB                                0x0000000118819b48 lldb::SBProcess::Kill() + 72
8   DebuggerLLDB                        0x0000000117264358 DBGLLDBSessionThread(void*) + 4450
9   LLDB                                0x0000000119568094 ThreadCreateTrampoline(void*) + 91
10  libsystem_c.dylib                   0x00007fff8ca028bf _pthread_start + 335
11  libsystem_c.dylib                   0x00007fff8ca05b75 thread_start + 13

fd=60 was created with this event:
pid=55222: socket (domain = 2, type = 1, protocol = 6) => fd=60
0   libFDInterposing.dylib              0x00000001082bc968 socket$__interposed__ + 600
1   LLDB                                0x00000001194fd75f lldb_private::ConnectionFileDescriptor::ConnectTCP(char const*, lldb_private::Error*) + 179
.....

llvm-svn: 149103

2 files changed, 7 insertions, 1 deletions

diff --git a/lldb/include/lldb/Core/ConnectionFileDescriptor.h b/lldb/include/lldb/Core/ConnectionFileDescriptor.h
index 44c98eb11da..b2a29d6c6e2 100644
--- a/lldb/include/lldb/Core/ConnectionFileDescriptor.h
+++ b/lldb/include/lldb/Core/ConnectionFileDescriptor.h
@@ -19,6 +19,7 @@
 // Other libraries and framework includes
 // Project includes
 #include "lldb/Core/Connection.h"
+#include "lldb/Host/Mutex.h"
 #include "lldb/Host/SocketAddress.h"
 
 namespace lldb_private {
@@ -104,6 +105,7 @@ protected:
     SocketAddress m_udp_send_sockaddr;
     bool m_should_close_fd; // True if this class should close the file descriptor when it goes away.
     uint32_t m_socket_timeout_usec;
+    Mutex m_mutex;
     
     static in_port_t
     GetSocketPort (int fd);
diff --git a/lldb/source/Core/ConnectionFileDescriptor.cpp b/lldb/source/Core/ConnectionFileDescriptor.cpp
index 6069f8beec5..b349a410b3e 100644
--- a/lldb/source/Core/ConnectionFileDescriptor.cpp
+++ b/lldb/source/Core/ConnectionFileDescriptor.cpp
@@ -73,7 +73,8 @@ ConnectionFileDescriptor::ConnectionFileDescriptor () :
     m_fd_recv_type (eFDTypeFile),
     m_udp_send_sockaddr (),
     m_should_close_fd (false), 
-    m_socket_timeout_usec(0)
+    m_socket_timeout_usec(0),
+    m_mutex (Mutex::eMutexTypeRecursive)
 {
     LogSP log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION |  LIBLLDB_LOG_OBJECT));
     if (log)
@@ -113,6 +114,7 @@ ConnectionFileDescriptor::IsConnected () const
 ConnectionStatus
 ConnectionFileDescriptor::Connect (const char *s, Error *error_ptr)
 {
+    Mutex::Locker locker (m_mutex);
     LogSP log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
     if (log)
         log->Printf ("%p ConnectionFileDescriptor::Connect (url = '%s')", this, s);
@@ -232,6 +234,7 @@ ConnectionFileDescriptor::Connect (const char *s, Error *error_ptr)
 ConnectionStatus
 ConnectionFileDescriptor::Disconnect (Error *error_ptr)
 {
+    Mutex::Locker locker (m_mutex);
     LogSP log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_CONNECTION));
     if (log)
         log->Printf ("%p ConnectionFileDescriptor::Disconnect ()", this);
@@ -599,6 +602,7 @@ ConnectionFileDescriptor::BytesAvailable (uint32_t timeout_usec, Error *error_pt
 ConnectionStatus
 ConnectionFileDescriptor::Close (int& fd, Error *error_ptr)
 {
+    Mutex::Locker locker (m_mutex);
     if (error_ptr)
         error_ptr->Clear();
     bool success = true;