[os-libsynthesis] Race condition writting global logs

[Andris Pavenis]

libsynthesis server engine uses open/close flush method unconditionally for
global logs which causes race condition when incomming SyncML requests
are processed from different threads with resulting SIGSEGV

Included patch seems to workaround the problem. Mutex is ignored unless
flush method is open/close.

Andris

PS. I know that global logs are disabled by default and are not recommended
in multi-user environment. Anyway SIGSEGV is not a good behavior.


--- libsynthesis_3.4.0.24/src/sysync/debuglogger.cpp.dbglog	2011-01-27 10:13:10.000000000 +0200
+++ libsynthesis_3.4.0.24/src/sysync/debuglogger.cpp	2011-08-25 13:05:37.000000000 +0300
@@ -287,12 +287,14 @@ TStdFileDbgOut::TStdFileDbgOut()
   // init
   fFileName.erase();
   fFile=NULL;
+  mutex=newMutex();
 } // TStdFileDbgOut::TStdFileDbgOut
 
 
 TStdFileDbgOut::~TStdFileDbgOut()
 {
   destruct();
+  freeMutex(mutex);
 } // TStdFileDbgOut::~TStdFileDbgOut
 
 
@@ -364,6 +366,7 @@ void TStdFileDbgOut::putLine(cAppCharP a
   if (fIsOpen) {
     if (fFlushMode==dbgflush_openclose) {
       // we need to open the file for append first
+      lockMutex(mutex);
       fFile=fopen(fFileName.c_str(),"a");
     }
     if (fFile) {
@@ -376,6 +379,7 @@ void TStdFileDbgOut::putLine(cAppCharP a
         // we need to close the file after every line of output
         fclose(fFile);
         fFile=NULL;
+        unlockMutex(mutex);
       }
       else if (aForceFlush || fFlushMode==dbgflush_flush) {
         // simply flush
@@ -392,6 +396,7 @@ void TStdFileDbgOut::putRawData(cAppPoin
   if (fIsOpen) {
     if (fFlushMode==dbgflush_openclose) {
       // we need to open the file for append first
+      lockMutex(mutex);
       fFile=fopen(fFileName.c_str(),"a");
     }
     if (fFile) {
@@ -404,6 +409,7 @@ void TStdFileDbgOut::putRawData(cAppPoin
       // we need to close the file after every line of output
       fclose(fFile);
       fFile=NULL;
+      unlockMutex(mutex);
     }
     else if (fFlushMode==dbgflush_flush) {
       // simply flush
--- libsynthesis_3.4.0.24/src/sysync/debuglogger.h.dbglog	2011-01-27 10:13:10.000000000 +0200
+++ libsynthesis_3.4.0.24/src/sysync/debuglogger.h	2011-08-25 13:10:44.000000000 +0300
@@ -17,6 +17,7 @@
 #ifdef SYDEBUG
 
 #include "generic_types.h"
+#include "platform_mutex.h"
 #include "sysync.h"
 
 namespace sysync {
@@ -169,6 +170,7 @@ private:
   TDbgFlushModes fFlushMode;
   string fFileName;
   FILE * fFile;
+  MutexPtr_t mutex;
 }; // TStdFileDbgOut
 
 #endif

_______________________________________________
os-libsynthesis mailing list
os-libsynthesis@synthesis.ch
http://lists.synthesis.ch/mailman/listinfo/os-libsynthesis