Handling SIGINT, 60% of the time it works every time.

Author: taszlan

src/Config.cpp

@@ -5,7 +5,9 @@
 #include <string.h>
 #include <vector>
 #include <map>
+#include <signal.h>
 #include "Config.h"
+#include "globals.h"
 #define CONFIG_SIZE 500
 /*
  * config - loads config file on demand, keeps the config in shared RO memory for fast access
@@ -16,6 +18,8 @@ std::map<string, string> configMap;
 Config::Config() {
     loadConfigFileToMap();
 }
+
+
 void Config::loadConfigFileToMap(){
     int configFileDescriptor = open("./config", O_RDONLY);
     char configFileContents[CONFIG_SIZE];

src/Config.h

@@ -3,6 +3,8 @@
 #include <iostream>
 #include <exception>
 #include <vector>
+#include <signal.h>
+
 
 class Config {
 	private:

src/Router.cpp

@@ -6,6 +6,7 @@
 #include "Config.h"
 #include "Router.h"
 #include "Manager.h"
+#include "globals.h"
 
 /*
  * router - watches the designated port and for launches a new worker for every connection
@@ -22,6 +23,7 @@ Router::Router(int qsize, std::string port) {
 }
 
 Router::~Router() {
+    this->logger->info("Destructor called");
     // close our socket
     close(this->listening_socket_fd);
     // free the address
@@ -48,15 +50,21 @@ void Router::watch() {
     Manager manager;
 
     // we work until we're told to stop working
-    while (true) {
+    while (!isSigintRecieved) {
         // listen for new connections
         listen(this->listening_socket_fd, this->queue_size);
 
         addr_size = sizeof client;
         handling_socket = accept(this->listening_socket_fd, (struct sockaddr *) &client, &addr_size);
+        cout << std::strerror(errno) << endl;
         if (handling_socket < 0) {
-            char * err = std::strerror(errno);
-            throw Router::Exception("Error when accepting connection: " + std::string(err ? err : "unknown error"));
+            if(errno == EINTR){
+                this->logger->info("Accept() interrupted by signal");
+                break;
+            } else {
+                char *err = std::strerror(errno);
+                throw Router::Exception("Error when accepting connection: " + std::string(err ? err : "unknown error"));
+            }
         }
 
         struct sockaddr_in *sin = (struct sockaddr_in *)&client;

src/SignalHandler.cpp

@@ -0,0 +1,32 @@
+//
+// Created by atticus on 12/9/15.
+//
+
+#include <string.h>
+#include <signal.h>
+#include <iostream>
+#include "SignalHandler.h"
+#include "globals.h"
+
+void SignalHandler::signalHandler(int sig, siginfo_t *siginfo, void *context){
+    std::cout << "Signal recieved: SignalHandler" << std::endl;
+    isSigintRecieved = true;
+}
+
+SignalHandler::~SignalHandler() {
+
+}
+
+SignalHandler::SignalHandler() {
+
+    struct sigaction act;
+    memset (&act, '\0', sizeof(act));
+    /* Use the sa_sigaction field because the handles has two additional parameters */
+    act.sa_sigaction = &signalHandler;
+    /* The SA_SIGINFO flag tells sigaction() to use the sa_sigaction field, not sa_handler. */
+    act.sa_flags = SA_SIGINFO;
+
+    if (sigaction(SIGINT, &act, NULL) < 0) {
+        std::cout <<"Signal error" <<std::endl;
+    }
+}

src/SignalHandler.h

@@ -0,0 +1,17 @@
+//
+// Created by atticus on 12/9/15.
+//
+
+#ifndef HACKTTP_SIGNALHANDLER_H
+#define HACKTTP_SIGNALHANDLER_H
+
+#include <signal.h>
+
+class SignalHandler{
+public:
+    virtual ~SignalHandler();
+    SignalHandler();
+    static void signalHandler(int, siginfo_t*, void*);
+};
+
+#endif //HACKTTP_SIGNALHANDLER_H

src/Worker.cpp

@@ -20,6 +20,7 @@ Worker::Worker(int socket_fd) {
 
 Worker::~Worker() {
     // make sure to close the socket when we finish
+    this->logger->info("Destructor called");
 	close(this->socket_fd);
     delete(this->logger);
 }
@@ -32,6 +33,11 @@ void Worker::handle_request() {
     // first read the request
     ssize_t request_size = recv(this->socket_fd, request, HTTP_REQUEST_LENGTH, 0);
     if(request_size < 0) {
+        // TODO not sure if necessary
+        if(errno == EINTR){
+            this->logger->info("Recv() interrupted by signal");
+            return;
+        }
         // TODO replace with proper HTTP response
         char * err = std::strerror(errno);
         throw Worker::Exception("Error while reading request: " + std::string(err ? err : "unknown error"));

src/globals.h

@@ -0,0 +1,10 @@
+//
+// Created by atticus on 12/8/15.
+//
+
+#ifndef HACKTTP_GLOBALS_H_H
+#define HACKTTP_GLOBALS_H_H
+
+extern bool isSigintRecieved;
+
+#endif //HACKTTP_GLOBALS_H_H

src/server.cpp

@@ -1,7 +1,11 @@
+#include <unistd.h>
+#include <string.h>
 #include "CmdLine.h"
 #include "Config.h"
 #include "Logger.h"
 #include "Router.h"
+#include "globals.h"
+#include "SignalHandler.h"
 
 /*
  * "main" - should use other modules for everything, that is:
@@ -10,15 +14,18 @@
  *	- bind the router tho the receiving port and give it control
  *	- when router finishes, log and shutdown
  */
+bool isSigintRecieved;
 
 int main() {
+    isSigintRecieved = false;
 	// Init basic classes
+    SignalHandler signalHandler;
 	CmdLine cmdline;
 	Config config;
     Logger logger("Server");
     //"hello from server.cpp" message, to be removed
     logger.info(config.get_str_setting("config_test"));
-
+    logger.info("Process id: " + std::to_string(getpid()));
     if(config.get_str_setting("start_full_server") == "true") {
         // starting the full server
         std::string port = config.get_str_setting("port");
@@ -36,6 +43,7 @@ int main() {
         logger.info("Running in test mode");
     }
 	// cleanup
+
 	logger.info("HackTTP shutting down");
 
 	return 0;