[textinput] handle Unix SIGTERM to save and close files before exit

Fixes #13300

[core] Implement public static functions allowing save and close

[io] only SaveAndClose TFiles and derived

TSystemFile, in general, does not implemente Write and Close methods

[io] Do not write/close files open in READ mode

[core] use TDirectory instead TMethodCall

Author: ferdymercury

core/base/inc/TROOT.h

@@ -344,6 +344,7 @@ friend TROOT *ROOT::Internal::GetROOT2();
    Int_t             Timer() const { return fTimer; }
 
    //---- static functions
+   static void        CleanUpROOTAtExit();
    static Int_t       DecreaseDirLevel();
    static Int_t       GetDirLevel();
    static const char *GetMacroPath();
@@ -356,6 +357,7 @@ friend TROOT *ROOT::Internal::GetROOT2();
    static Int_t       ConvertVersionCode2Int(Int_t code);
    static Int_t       ConvertVersionInt2Code(Int_t v);
    static Int_t       RootVersionCode();
+   static void        WriteCloseAllFiles();
    static const std::vector<std::string> &AddExtraInterpreterArgs(const std::vector<std::string> &args);
    static const char**&GetExtraInterpreterArgs();
 

core/base/src/TROOT.cxx

@@ -119,6 +119,7 @@ FARPROC dlsym(void *library, const char *function_name)
 #include "TClass.h"
 #include "TClassEdit.h"
 #include "TClassGenerator.h"
+#include "TDirectory.h"
 #include "TDataType.h"
 #include "TStyle.h"
 #include "TObjectTable.h"
@@ -226,10 +227,33 @@ static Int_t ITIMQQ(const char *time)
    return 100*hh + mm;
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// Write and Close all open writable TFiles, useful to be called when SIGTERM is caught.
+
+void TROOT::WriteCloseAllFiles()
+{
+   if (gROOT) {
+      R__LOCKGUARD(gROOTMutex);
+
+      if (gROOT->GetListOfFiles()) {
+         TIter next(gROOT->GetListOfFiles());
+         while (TObject *obj = next()) {
+            if (obj && obj->InheritsFrom(TClass::GetClass("TFile", kFALSE, kTRUE))) {
+               auto fobj = static_cast<TDirectory *>(obj);
+               if (fobj->IsWritable()) {
+                  fobj->Write();
+                  fobj->Close();
+               }
+            }
+         }
+      }
+   }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// Clean up at program termination before global objects go out of scope.
 
-static void CleanUpROOTAtExit()
+void TROOT::CleanUpROOTAtExit()
 {
    if (gROOT) {
       R__LOCKGUARD(gROOTMutex);

core/textinput/src/textinput/TerminalConfigUnix.cpp

@@ -24,6 +24,8 @@
 #include <stdio.h>
 #include <cstring>
 
+#include <TROOT.h>
+
 using namespace textinput;
 using std::memcpy;
 using std::signal;
@@ -104,6 +106,11 @@ TerminalConfigUnix::HandleSignal(int signum) {
     }
   }
 
+  // gentle save and close if SIGTERM
+  if (signum == SIGTERM) {
+     TROOT::WriteCloseAllFiles();
+     TROOT::CleanUpROOTAtExit();
+  }
   // No previous handler found, re-raise to get default handling:
   signal(signum, SIG_DFL); // unregister ourselves
   raise(signum); // terminate through default handler