thread safety

server/mail.cpp

@@ -1,17 +1,20 @@
 #include "mail.h"
+#include <mutex>
 
 mail::mail(std::string filename, std::string subject) :
 	filename(filename),
 	timestamp(std::time(NULL)),
 	subject(subject),
-	deleted(false)
+	deleted(false),
+	m_file()
 {}
 
 mail::mail(std::string filename, int64_t timestamp, std::string subject) :
 	filename(filename),
 	timestamp(timestamp),
 	subject(subject),
-	deleted(false)
+	deleted(false),
+	m_file()
 {}
 
 /*

server/mail.h

@@ -37,4 +37,6 @@ struct mail {
 	json mailToJson();
 
 	void remove();
+
+	std::mutex m_file;
 };

server/server.cpp

@@ -14,6 +14,7 @@
 #include <cctype>
 #include <algorithm> 
 #include <future>
+#include <mutex>
 #include <pthread.h>
 #include <string_view>
 #include <sstream>
@@ -43,10 +44,12 @@ enum commands {
 
 namespace fs = std::filesystem;
 
-int abortRequested = 0;
+bool abortRequested = false;
 int create_socket = -1;
 int new_socket = -1;
 
+std::vector<std::thread> threads;
+
 void printUsage();
 inline bool isInteger(const std::string & s);
 bool ichar_equals(char a, char b);
@@ -166,8 +169,7 @@ int main (int argc, char* argv[])
 				 inet_ntoa(cliaddress.sin_addr),
 				 ntohs(cliaddress.sin_port));
 		// clientCommunication(&new_socket); // returnValue can be ignored
-		std::thread th(clientCommunication, new_socket);
+		threads.emplace_back(clientCommunication, new_socket);
-		th.detach();
 		new_socket = -1;
 	}
 
@@ -305,7 +307,7 @@ void signalHandler(int sig)
 {
 	if (sig == SIGINT) {
 		printf("abort Requested... "); // ignore error
-		abortRequested = 1;
+		abortRequested = true;
 		if (new_socket != -1)
 		{
 			if (shutdown(new_socket, SHUT_RDWR) == -1)
@@ -363,6 +365,10 @@ std::string getSha1(const std::string& str)
 
 inline void exiting()
 {
+    for (auto& thread : threads) {
+    	thread.join();
+    }
+
 	user_handler::getInstance().saveAll();
 	printf("Saving...	\n");
 }
@@ -420,13 +426,14 @@ std::string cmdREAD(std::vector<std::string>& received)
 		mail->deleted)
 		return "ERR\n";
 
-	try {
+	/*try */{
 		std::string path_str = user_handler::getInstance().getSpoolDir()/"messages"/mail->filename;
+		std::lock_guard<std::mutex> guard(mail->m_file);
 		response.append(read_file(path_str)).append("\n");
 	}
-	catch (...) { // TODO: more specific error handling - then again, it will respond with ERR either way
+	/*catch (...) { // TODO: more specific error handling - then again, it will respond with ERR either way
 		return "ERR\n";
-	}
+	}*/
 
 	return response;
 }

server/user.cpp

@@ -4,6 +4,7 @@
 
 #include <cstdio>
 #include <fstream>
+#include <mutex>
 #include <ostream>
 #include <string>
 #include <vector>
@@ -11,7 +12,7 @@
 
 using json = nlohmann::json;
 
-user::user(fs::path user_data_json)
+user::user(fs::path user_data_json) : m()
 {
 	std::ifstream ifs(user_data_json);
 	json user_data = json::parse(ifs);
@@ -50,7 +51,8 @@ user::user(fs::path user_data_json)
 }
 
 user::user(std::string name, fs::path user_dir)
-	: name(name)
+	: name(name),
+	  m()
 {
 	json user;
 	user["mails"]["sent"] = json::object();
@@ -69,6 +71,8 @@ user::~user() {
 
 void user::addMail(mail* mail) 
 {
+	std::lock_guard<std::mutex> guard(this->m);
+
 	mail->id = this->inbox.size();
 
 	this->inbox.insert(mail);
@@ -77,6 +81,8 @@ void user::addMail(mail* mail)
 
 void user::sendMail(mail* mail, std::vector<std::string> recipients) 
 {
+	std::lock_guard<std::mutex> guard(this->m);
+
 	std::vector<user*> users;
 	for ( auto& name : recipients) {
 		// TODO: error handling for non existing user
@@ -104,6 +110,8 @@ mail* user::getMail(u_int id)
 
 bool user::delMail(u_int id) 
 {
+	std::lock_guard<std::mutex> guard(this->m);
+
 	maillist::iterator it = std::find_if(this->inbox.begin(), this->inbox.end(), [id](auto& i){ return (*i)(id); });
 
 	bool success = true;

server/user.h

@@ -2,6 +2,7 @@
 
 #include "mail.h"
 
+#include <mutex>
 #include <string>
 #include <set>
 #include <vector>
@@ -37,4 +38,6 @@ private:
 	std::string name;
 	maillist inbox;
 	maillist sent;
+
+	std::mutex m;
 };

server/user_handler.cpp

@@ -4,7 +4,7 @@
 #include <filesystem>
 #include <string>
 
-user_handler::user_handler()
+user_handler::user_handler() : m_user()
 {
 	for (const auto& entry : fs::directory_iterator()) {
 		if (entry.path().extension() == ".json") {
@@ -21,26 +21,31 @@ user_handler::~user_handler()
 user* user_handler::getUser(std::string name)
 {
 	if (this->users.find(name) == this->users.end()) {
+		this->m_user.lock(); // avoid race condition of two threads creating the same user
 		if (!fs::exists(this->spool_dir/"users"/(name+".json")))
 			return nullptr;
 
-		this->users[name] = new user(this->spool_dir/"users"/(name+".json"));
+		this->users.insert({name, new user(this->spool_dir/"users"/(name+".json"))});
+		this->m_user.unlock();
 	}
-	return this->users[name]; 
+	return (*this->users.find(name)).second; 
 }
 
 user* user_handler::getOrCreateUser(std::string name)
 {
 	if (this->users.find(name) == this->users.end()) {
-		this->users[name] = fs::exists(this->spool_dir/"users"/(name+".json")) ?
+		this->m_user.lock();
+		this->users.insert({name, fs::exists(this->spool_dir/"users"/(name+".json")) ?
 			new user(this->spool_dir/"users"/(name+".json")) :
-			new user(name, this->spool_dir/"users");
+			new user(name, this->spool_dir/"users")});
+		this->m_user.unlock();
 	}
 	return this->users[name]; 
 }
 
 void user_handler::saveAll()
 {
+	// will only be called from main
 	for ( auto& user : this->users ) {
 		user.second->saveToFile();
 	}

server/user_handler.h

@@ -2,6 +2,7 @@
 
 #include <filesystem>
 #include <map>
+#include <mutex>
 #include <string>
 
 class user;
@@ -38,4 +39,6 @@ protected:
 	fs::path spool_dir;
 	std::map<std::string, user*> users;
 
+	std::mutex m_user;
+	
 };