[Startup][Refactor][Backport]

* OS memory allocation fail handler.
* OS signal handler registration method created to remove code duplication.
* AppInitBasicSetup() method created, organizing better the setup step of the wallet initialization.

src/init.cpp

@@ -307,14 +307,25 @@ void Shutdown()
  */
 void HandleSIGTERM(int)
 {
- fRequestShutdown = true;
+ StartShutdown();
 }
 
 void HandleSIGHUP(int)
 {
  fReopenDebugLog = true;
 }
 
+#ifndef WIN32
+static void registerSignalHandler(int signal, void(*handler)(int))
+{
+ struct sigaction sa;
+ sa.sa_handler = handler;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = 0;
+ sigaction(signal, &sa, nullptr);
+}
+#endif
+
 bool static InitError(const std::string& str)
 {
  uiInterface.ThreadSafeMessageBox(str, "", CClientUIInterface::MSG_ERROR);
@@ -748,10 +759,20 @@ bool AppInitServers()
  return true;
 }
 
-/** Initialize pivx.
- * @pre Parameters should be parsed and config file should be read.
- */
-bool AppInit2()
+[[noreturn]] static void new_handler_terminate()
+{
+ // Rather than throwing std::bad-alloc if allocation fails, terminate
+ // immediately to (try to) avoid chain corruption.
+ // Since LogPrintf may itself allocate memory, set the handler directly
+ // to terminate first.
+ std::set_new_handler(std::terminate);
+ LogPrintf("Error: Out of memory. Terminating.\n");
+
+ // The log was successful, terminate now.
+ std::terminate();
+};
+
+bool AppInitBasicSetup()
 {
 // ********************************************************* Step 1: setup
 #ifdef _MSC_VER
@@ -764,7 +785,7 @@ bool AppInit2()
  _set_abort_behavior(0, _WRITE_ABORT_MSG | _CALL_REPORTFAULT);
 #endif
 #ifdef WIN32
-// Enable Data Execution Prevention (DEP)
+ // Enable Data Execution Prevention (DEP)
 // Minimum supported OS versions: WinXP SP3, WinVista >= SP1, Win Server 2008
 // A failure is non-critical and needs no further attention!
 #ifndef PROCESS_DEP_ENABLE
@@ -790,26 +811,31 @@ bool AppInit2()
  umask(077);
  }
 
-
- // Clean shutdown on SIGTERM
- struct sigaction sa;
- sa.sa_handler = HandleSIGTERM;
- sigemptyset(&sa.sa_mask);
- sa.sa_flags = 0;
- sigaction(SIGTERM, &sa, NULL);
- sigaction(SIGINT, &sa, NULL);
+ // Clean shutdown on SIGTERMx
+ registerSignalHandler(SIGTERM, HandleSIGTERM);
+ registerSignalHandler(SIGINT, HandleSIGTERM);
 
  // Reopen debug.log on SIGHUP
- struct sigaction sa_hup;
- sa_hup.sa_handler = HandleSIGHUP;
- sigemptyset(&sa_hup.sa_mask);
- sa_hup.sa_flags = 0;
- sigaction(SIGHUP, &sa_hup, NULL);
+ registerSignalHandler(SIGHUP, HandleSIGHUP);
 
  // Ignore SIGPIPE, otherwise it will bring the daemon down if the client closes unexpectedly
  signal(SIGPIPE, SIG_IGN);
 #endif
 
+ std::set_new_handler(new_handler_terminate);
+
+ return true;
+}
+
+/** Initialize pivx.
+ * @pre Parameters should be parsed and config file should be read.
+ */
+bool AppInit2()
+{
+ // ********************************************************* Step 1: setup
+ if (!AppInitBasicSetup())
+ return false;
+
  // ********************************************************* Step 2: parameter interactions
  // Set this early so that parameter interactions go to console
  fPrintToConsole = GetBoolArg("-printtoconsole", false);

src/init.h

@@ -29,6 +29,12 @@ void Shutdown();
 void PrepareShutdown();
 bool AppInit2();
 
+/** Initialize PIVX core: Basic context setup.
+ * @note This can be done before daemonization. Do not call Shutdown() if this function fails.
+ * @pre Parameters should be parsed and config file should be read.
+ */
+bool AppInitBasicSetup();
+
 /** The help message mode determines what help message to show */
 enum HelpMessageMode {
  HMM_BITCOIND,