add signal handler with crash logging

lib/common/src/version.h

@@ -7,4 +7,4 @@
 
 #pragma once
 
-#define NCHAT_VERSION "4.26"
+#define NCHAT_VERSION "4.27"

lib/ncutil/src/apputil.cpp

@@ -1,12 +1,16 @@
 // apputil.cpp
 //
-// Copyright (c) 2020-2023 Kristofer Berggren
+// Copyright (c) 2020-2024 Kristofer Berggren
 // All rights reserved.
 //
 // nchat is distributed under the MIT license, see LICENSE for details.
 
 #include "apputil.h"
 
+#include <set>
+
+#include <execinfo.h>
+#include <signal.h>
 #include <unistd.h>
 
 #include <sys/resource.h>
@@ -69,3 +73,40 @@ void AppUtil::InitCoredump()
   }
 #endif
 }
+
+void AppUtil::InitSignalHandler()
+{
+  static const std::set<int> signals =
+  {
+    SIGABRT,
+    SIGBUS,
+    SIGFPE,
+    SIGILL,
+    SIGQUIT,
+    SIGSEGV,
+    SIGSYS,
+    SIGTRAP,
+  };
+
+  for (const auto sig : signals)
+  {
+    signal(sig, SignalHandler);
+  }
+}
+
+void AppUtil::SignalHandler(int p_Signal)
+{
+  char logMsg[64];
+  snprintf(logMsg, sizeof(logMsg), "Unexpected termination %d\nCallstack:\n", p_Signal);
+  void* callstack[64] = { 0 };
+  const int size = backtrace(callstack, sizeof(callstack));
+  Log::Callstack(callstack, size, logMsg);
+
+  // non-signal safe code section
+  system("reset");
+  write(STDERR_FILENO, logMsg, strlen(logMsg));
+  backtrace_symbols_fd(callstack, size, STDERR_FILENO);
+
+  signal(p_Signal, SIG_DFL);
+  kill(getpid(), p_Signal);
+}

lib/ncutil/src/apputil.h

@@ -1,6 +1,6 @@
 // apputil.h
 //
-// Copyright (c) 2020-2023 Kristofer Berggren
+// Copyright (c) 2020-2024 Kristofer Berggren
 // All rights reserved.
 //
 // nchat is distributed under the MIT license, see LICENSE for details.
@@ -17,6 +17,8 @@ class AppUtil
   static void SetDeveloperMode(bool p_DeveloperMode);
   static bool GetDeveloperMode();
   static void InitCoredump();
+  static void InitSignalHandler();
+  static void SignalHandler(int p_Signal);
 
 private:
   static bool m_DeveloperMode;

lib/ncutil/src/log.cpp

@@ -1,25 +1,40 @@
 // log.cpp
 //
-// Copyright (c) 2020-2023 Kristofer Berggren
+// Copyright (c) 2020-2024 Kristofer Berggren
 // All rights reserved.
 //
 // nchat is distributed under the MIT license, see LICENSE for details.
 
 #include "log.h"
 
+#include <execinfo.h>
+#include <fcntl.h>
 #include <stdarg.h>
+#include <unistd.h>
+
 #include <sys/time.h>
 
 std::string Log::m_Path;
 int Log::m_VerboseLevel = 0;
 std::mutex Log::m_Mutex;
+int Log::m_LogFd = -1;
 
 void Log::Init(const std::string& p_Path)
 {
   m_Path = p_Path;
   const std::string archivePath = m_Path + ".1";
   remove(archivePath.c_str());
   rename(m_Path.c_str(), archivePath.c_str());
+  Dump("");
+  m_LogFd = open(m_Path.c_str(), O_WRONLY | O_APPEND);
+}
+
+void Log::Cleanup()
+{
+  if (m_LogFd != -1)
+  {
+    close(m_LogFd);
+  }
 }
 
 void Log::SetVerboseLevel(int p_Level)
@@ -86,7 +101,17 @@ void Log::Dump(const char* p_Str)
   }
 }
 
-void Log::Write(const char* p_Filename, int p_LineNo, const char* p_Level, const char* p_Format, va_list p_VaList)
+void Log::Callstack(void* const* p_Callstack, int p_Size, const char* p_LogMsg)
+{
+  if (m_LogFd != -1)
+  {
+    write(m_LogFd, p_LogMsg, strlen(p_LogMsg));
+    backtrace_symbols_fd(p_Callstack, p_Size, m_LogFd);
+  }
+}
+
+void Log::Write(const char* p_Filename, int p_LineNo, const char* p_Level,
+                const char* p_Format, va_list p_VaList)
 {
   std::unique_lock<std::mutex> lock(m_Mutex);
   if (m_Path.empty()) return;

lib/ncutil/src/log.h

@@ -1,6 +1,6 @@
 // log.h
 //
-// Copyright (c) 2020-2023 Kristofer Berggren
+// Copyright (c) 2020-2024 Kristofer Berggren
 // All rights reserved.
 //
 // nchat is distributed under the MIT license, see LICENSE for details.
@@ -27,6 +27,7 @@ class Log
   static const int TRACE_LEVEL = 2;
 
   static void Init(const std::string& p_Path);
+  static void Cleanup();
   static void SetVerboseLevel(int p_Level);
   static inline int GetVerboseLevel() { return m_VerboseLevel; }
   static inline bool GetDebugEnabled() { return m_VerboseLevel >= DEBUG_LEVEL; }
@@ -39,12 +40,15 @@ class Log
   static void Error(const char* p_Filename, int p_LineNo, const char* p_Format, ...);
 
   static void Dump(const char* p_Str);
+  static void Callstack(void* const* p_Callstack, int p_Size, const char* p_LogMsg);
 
 private:
-  static void Write(const char* p_Filename, int p_LineNo, const char* p_Level, const char* p_Format, va_list p_VaList);
+  static void Write(const char* p_Filename, int p_LineNo, const char* p_Level,
+                    const char* p_Format, va_list p_VaList);
 
 private:
   static std::string m_Path;
   static int m_VerboseLevel;
   static std::mutex m_Mutex;
+  static int m_LogFd;
 };

src/main.cpp

@@ -238,6 +238,9 @@ int main(int argc, char* argv[])
   std::string appNameVersion = AppUtil::GetAppNameVersion();
   LOG_INFO("starting %s", appNameVersion.c_str());
 
+  // Init signal handler
+  AppUtil::InitSignalHandler();
+
   // Run keydump if required
   if (isKeyDump)
   {
@@ -389,6 +392,8 @@ int main(int argc, char* argv[])
 
   LOG_INFO("exiting nchat");
 
+  Log::Cleanup();
+
   return rv;
 }
 

src/nchat.1

@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH NCHAT "1" "January 2024" "nchat v4.26" "User Commands"
+.TH NCHAT "1" "January 2024" "nchat v4.27" "User Commands"
 .SH NAME
 nchat \- ncurses chat
 .SH SYNOPSIS