add pidfile option

include/llarp.hpp

@@ -65,6 +65,16 @@ namespace llarp
     HandleSignal(int sig);
 
    private:
+
+    void 
+    SetPIDFile(const std::string & fname);
+
+    bool
+    WritePIDFile() const;
+
+    void
+    RemovePIDFile() const;
+
     bool
     Configure();
 
@@ -82,6 +92,7 @@ namespace llarp
     progress();
 
     std::string configfile;
+    std::string pidfile;
   };
 }  // namespace llarp
 

llarp/config.cpp

@@ -151,6 +151,7 @@ llarp_generic_ensure_config(std::ofstream &f, std::string basepath)
   f << "# ";
 #endif
   f << "group=" << DEFAULT_LOKINET_GROUP << std::endl;
+  f << "pidfile=" << basepath << "lokinet.pid" << std::endl;
   f << std::endl << std::endl;
 
   f << "# dns provider configuration section" << std::endl;

llarp/context.cpp

@@ -53,6 +53,13 @@ namespace llarp
                        const char *key, const char *val)
   {
     Context *ctx = static_cast< Context * >(itr->user);
+    if(!strcmp(section, "system"))
+    {
+      if(!strcmp(key, "pidfile"))
+      {
+        ctx->SetPIDFile(val);
+      }
+    }
     if(!strcmp(section, "router"))
     {
       if(!strcmp(key, "worker-threads") && !ctx->singleThreaded)
@@ -81,6 +88,12 @@ namespace llarp
     }
   }
 
+  void 
+  Context::SetPIDFile(const std::string & fname)
+  {
+    pidfile = fname;
+  }
+
   int
   Context::LoadDatabase()
   {
@@ -174,9 +187,12 @@ namespace llarp
       llarp::LogError("cannot run non configured context");
       return 1;
     }
+    if(!WritePIDFile())
+      return 1;
     // run
     if(!router->Run(nodedb))
       return 1;
+    
     // run net io thread
     llarp::LogInfo("running mainloop");
     llarp_ev_loop_run_single_process(mainloop, worker, logic);
@@ -184,6 +200,34 @@ namespace llarp
     return 0;
   }
 
+  bool
+  Context::WritePIDFile() const
+  {
+    if(pidfile.size())
+    {
+      std::ofstream f(pidfile);
+      f << std::to_string(getpid());
+      return f.good();
+    }
+    else
+      return true;
+  }
+
+  void
+  Context::RemovePIDFile() const
+  {
+    if(pidfile.size())
+    {
+      fs::path f = pidfile;
+      std::error_code ex;
+      if(fs::exists(f, ex))
+      {
+        if(!ex)
+          fs::remove(f);
+      }
+    }
+  }
+
   void
   Context::HandleSignal(int sig)
   {
@@ -277,6 +321,7 @@ namespace llarp
       delete logic;
       logic = nullptr;
     }
+    RemovePIDFile();
   }
 
   bool