Related fdo#33484: Terminate OfficeIPCThread by closing the accepting pipe

... (and setting mbDowning to indicate an error returned from accept() is due to
termination) instead of setting up an extra pipe connection to send an
"InternalIPC::TerminateThread" message (which allegedly caused deadlocks, see
<https://gerrit.libreoffice.org/#/c/1311/> "Change Idf933915: office ipc: use
timeout pipe feature when connecting to self").

Change-Id: Id302ca13112fc409685e7665b38f1030704a0ccf

2 files changed, 23 insertions, 32 deletions

diff --git a/desktop/source/app/officeipcthread.cxx b/desktop/source/app/officeipcthread.cxx
index e287d2b4ec2b..882831132d39 100644
--- a/desktop/source/app/officeipcthread.cxx
+++ b/desktop/source/app/officeipcthread.cxx
@@ -51,8 +51,6 @@ using ::rtl::OString;
 using ::rtl::OUString;
 using ::rtl::OUStringBuffer;
 
-const char  *OfficeIPCThread::sc_aTerminationSequence = "InternalIPC::TerminateThread";
-const int OfficeIPCThread::sc_nTSeqLength = 28;
 const char  *OfficeIPCThread::sc_aShowSequence = "-tofront";
 const int OfficeIPCThread::sc_nShSeqLength = 5;
 const char  *OfficeIPCThread::sc_aConfirmationSequence = "InternalIPC::ProcessingDone";
@@ -427,8 +425,6 @@ OfficeIPCThread::Status OfficeIPCThread::EnableOfficeIPCThread()
 
     rtl::Reference< OfficeIPCThread > pThread(new OfficeIPCThread);
 
-    pThread->maPipeIdent = OUString( "SingleOfficeIPC_"  );
-
     // The name of the named pipe is created with the hashcode of the user installation directory (without /user). We have to retrieve
     // this information from a unotools implementation.
     ::utl::Bootstrap::PathStatus aLocateResult = ::utl::Bootstrap::locateUserInstallation( aUserInstallPath );
@@ -485,19 +481,19 @@ OfficeIPCThread::Status OfficeIPCThread::EnableOfficeIPCThread()
     if ( aUserInstallPathHashCode.isEmpty() )
         return IPC_STATUS_BOOTSTRAP_ERROR; // Something completely broken, we cannot create a valid hash code!
 
-    pThread->maPipeIdent = pThread->maPipeIdent + aUserInstallPathHashCode;
+    OUString aPipeIdent( "SingleOfficeIPC_" + aUserInstallPathHashCode );
 
     PipeMode nPipeMode = PIPEMODE_DONTKNOW;
     do
     {
         osl::Security &rSecurity = Security::get();
         // Try to create pipe
-        if ( pThread->maPipe.create( pThread->maPipeIdent.getStr(), osl_Pipe_CREATE, rSecurity ))
+        if ( pThread->maPipe.create( aPipeIdent.getStr(), osl_Pipe_CREATE, rSecurity ))
         {
             // Pipe created
             nPipeMode = PIPEMODE_CREATED;
         }
-        else if( pThread->maPipe.create( pThread->maPipeIdent.getStr(), osl_Pipe_OPEN, rSecurity )) // Creation not successfull, now we try to connect
+        else if( pThread->maPipe.create( aPipeIdent.getStr(), osl_Pipe_OPEN, rSecurity )) // Creation not successfull, now we try to connect
         {
             osl::StreamPipe aStreamPipe(pThread->maPipe.getHandle());
             char pReceiveBuffer[sc_nCSASeqLength + 1];
@@ -601,18 +597,8 @@ void OfficeIPCThread::DisableOfficeIPCThread(bool join)
             pGlobalOfficeIPCThread);
         pGlobalOfficeIPCThread.clear();
 
-        // send thread a termination message
-        // this is done so the subsequent join will not hang
-        // because the thread hangs in accept of pipe
-        osl::StreamPipe aPipe ( pOfficeIPCThread->maPipeIdent, osl_Pipe_OPEN, Security::get() );
-        if (aPipe.is())
-        {
-            aPipe.send( sc_aTerminationSequence, sc_nTSeqLength+1 ); // also send 0-byte
-
-            // close the pipe so that the streampipe on the other
-            // side produces EOF
-            aPipe.close();
-        }
+        pOfficeIPCThread->mbDowning = true;
+        pOfficeIPCThread->maPipe.close();
 
         // release mutex to avoid deadlocks
         aMutex.clear();
@@ -680,22 +666,23 @@ void OfficeIPCThread::execute()
             // down during wait
             osl::ClearableMutexGuard aGuard( GetMutex() );
 
-            if (!mbDowning)
+            if ( mbDowning )
             {
-                // notify client we're ready to process its args
-                int nBytes = 0;
-                int nResult = 0;
-                while (
-                    (nResult = aStreamPipe.send(sc_aSendArgumentsSequence+nBytes, sc_nCSASeqLength-nBytes))>0 &&
-                    ((nBytes += nResult) < sc_nCSASeqLength) ) ;
+                break;
             }
+
+            // notify client we're ready to process its args
+            int nBytes = 0;
+            int nResult;
+            while (
+                (nResult = aStreamPipe.send(sc_aSendArgumentsSequence+nBytes, sc_nCSASeqLength-nBytes))>0 &&
+                ((nBytes += nResult) < sc_nCSASeqLength) ) ;
             aStreamPipe.write("\0", 1);
 
             // test byte by byte
             const int nBufSz = 2048;
             char pBuf[nBufSz];
-            int nBytes = 0;
-            int nResult = 0;
+            nBytes = 0;
             rtl::OStringBuffer aBuf;
             // read into pBuf until '\0' is read or read-error
             while ((nResult=aStreamPipe.recv( pBuf+nBytes, nBufSz-nBytes))>0) {
@@ -713,9 +700,6 @@ void OfficeIPCThread::execute()
             if (aArguments.isEmpty())
                 continue;
 
-            // is this a termination message ? if so, terminate
-            if (aArguments.equalsL(sc_aTerminationSequence, sc_nTSeqLength) || mbDowning)
-                return;
             std::auto_ptr< CommandLineArgs > aCmdLineArgs;
             try
             {
@@ -932,6 +916,14 @@ void OfficeIPCThread::execute()
         }
         else
         {
+            {
+                osl::MutexGuard aGuard( GetMutex() );
+                if ( mbDowning )
+                {
+                    break;
+                }
+            }
+
 #if (OSL_DEBUG_LEVEL > 1) || defined DBG_UTIL
             fprintf( stderr, "Error on accept: %d\n", (int)nError );
 #endif
diff --git a/desktop/source/app/officeipcthread.hxx b/desktop/source/app/officeipcthread.hxx
index c07da3d9ce63..440fd247d2a9 100644
--- a/desktop/source/app/officeipcthread.hxx
+++ b/desktop/source/app/officeipcthread.hxx
@@ -72,7 +72,6 @@ class OfficeIPCThread : public salhelper::Thread
     static rtl::Reference< OfficeIPCThread > pGlobalOfficeIPCThread;
 
     osl::Pipe                   maPipe;
-    rtl::OUString               maPipeIdent;
     bool                        mbDowning;
     bool                        mbRequestsEnabled;
     int                         mnPendingRequests;