From 6ea3c8f4d1fcdcd81542b49319b9990de7ef9a16 Mon Sep 17 00:00:00 2001
From: Jeremy Latt <jlatt@apartmentlist.com>
Date: Thu, 13 Feb 2014 23:16:07 -0800
Subject: [PATCH] fix race conditions

---
 README.md     |  1 +
 irc/client.go | 18 +++++++++++++++---
 irc/socket.go | 19 +++++++++++++++----
 3 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index f7e46dc0..e09d06dd 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,7 @@ I wanted to learn Go.
 - [RFC 2811: IRC Channel Management](http://tools.ietf.org/html/rfc2811)
 - [RFC 2812: IRC Client Protocol](http://tools.ietf.org/html/rfc2812)
 - [RFC 2813: IRC Server Protocol](http://tools.ietf.org/html/rfc2813)
+- [IRC/2 Numeric List](https://www.alien.net.au/irc/irc2numerics.html)
 
 ## Running the Server
 
diff --git a/irc/client.go b/irc/client.go
index 325f5a85..cf44a1f4 100644
--- a/irc/client.go
+++ b/irc/client.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"net"
+	"sync"
 	"time"
 )
 
@@ -26,6 +27,7 @@ type Client struct {
 	replies     chan Reply
 	server      *Server
 	socket      *Socket
+	mutex       *sync.Mutex
 	authorized  bool
 	username    string
 }
@@ -40,6 +42,7 @@ func NewClient(server *Server, conn net.Conn) *Client {
 		replies:  make(chan Reply),
 		server:   server,
 		socket:   NewSocket(conn),
+		mutex:    &sync.Mutex{},
 	}
 	client.loginTimer = time.AfterFunc(LOGIN_TIMEOUT, client.Destroy)
 
@@ -50,7 +53,7 @@ func NewClient(server *Server, conn net.Conn) *Client {
 }
 
 func (client *Client) Touch() {
-	if client.destroyed {
+	if client.IsDestroyed() {
 		return
 	}
 
@@ -86,7 +89,7 @@ func (client *Client) ConnectionTimeout() {
 }
 
 func (client *Client) ConnectionClosed() {
-	if client.destroyed {
+	if client.IsDestroyed() {
 		return
 	}
 
@@ -133,8 +136,14 @@ func (client *Client) writeReplies() {
 	}
 }
 
+func (client *Client) IsDestroyed() bool {
+	client.mutex.Lock()
+	defer client.mutex.Unlock()
+	return client.destroyed
+}
+
 func (client *Client) Destroy() {
-	if client.destroyed {
+	if client.IsDestroyed() {
 		return
 	}
 
@@ -142,6 +151,7 @@ func (client *Client) Destroy() {
 		log.Printf("%s destroying", client)
 	}
 
+	client.mutex.Lock()
 	client.destroyed = true
 
 	if client.replies != nil {
@@ -164,6 +174,8 @@ func (client *Client) Destroy() {
 
 	client.server.clients.Remove(client)
 
+	client.mutex.Unlock()
+
 	if DEBUG_CLIENT {
 		log.Printf("%s destroyed", client)
 	}
diff --git a/irc/socket.go b/irc/socket.go
index f635ec50..c77d2d2c 100644
--- a/irc/socket.go
+++ b/irc/socket.go
@@ -6,15 +6,17 @@ import (
 	"log"
 	"net"
 	"strings"
+	"sync"
 )
 
 type Socket struct {
 	closed  bool
 	conn    net.Conn
+	mutex   *sync.Mutex
 	reader  *bufio.Reader
-	writer  *bufio.Writer
-	send    chan string
 	receive chan string
+	send    chan string
+	writer  *bufio.Writer
 }
 
 func NewSocket(conn net.Conn) *Socket {
@@ -23,6 +25,7 @@ func NewSocket(conn net.Conn) *Socket {
 		reader:  bufio.NewReader(conn),
 		receive: make(chan string),
 		send:    make(chan string),
+		mutex:   &sync.Mutex{},
 		writer:  bufio.NewWriter(conn),
 	}
 
@@ -36,8 +39,14 @@ func (socket *Socket) String() string {
 	return socket.conn.RemoteAddr().String()
 }
 
+func (socket *Socket) IsClosed() bool {
+	socket.mutex.Lock()
+	defer socket.mutex.Unlock()
+	return socket.closed
+}
+
 func (socket *Socket) Close() {
-	if socket.closed {
+	if socket.IsClosed() {
 		return
 	}
 
@@ -45,10 +54,12 @@ func (socket *Socket) Close() {
 		log.Printf("%s closed", socket)
 	}
 
+	socket.mutex.Lock()
 	socket.closed = true
 	socket.conn.Close()
 	close(socket.send)
 	close(socket.receive)
+	socket.mutex.Unlock()
 }
 
 func (socket *Socket) Read() <-chan string {
@@ -57,7 +68,7 @@ func (socket *Socket) Read() <-chan string {
 
 func (socket *Socket) Write(lines []string) error {
 	for _, line := range lines {
-		if socket.closed {
+		if socket.IsClosed() {
 			return io.EOF
 		}
 		socket.send <- line