Fix UNIX socket support.

config.yaml

@@ -8,7 +8,8 @@ name: Test
 address: "[::]"
 port: 5000
 
-# Alternatively, lurkcoin can bind on a UNIX domain socket.
+# Alternatively, lurkcoin can bind on a UNIX domain socket. The socket will be
+# world-writable.
 # network_protocol: unix
 # address: "/tmp/lurkcoin.sock"
 

lurkcoin/api/config.go

@@ -151,6 +151,11 @@ func StartServer(config *Config) {
 		log.Printf("Starting server on http://%s/", urlAddress)
 	}
 
+	// Remove any socket file that already exists
+	if networkProtocol == "unix" {
+		os.Remove(address)
+	}
+
 	// Bind to the address
 	var ln net.Listener
 	ln, err = net.Listen(networkProtocol, address)
@@ -158,6 +163,13 @@ func StartServer(config *Config) {
 		log.Fatal(err)
 	}
 
+	// Change permissions on the UNIX socket
+	if networkProtocol == "unix" {
+		if err := os.Chmod(address, 0777); err != nil {
+			log.Fatal(err)
+		}
+	}
+
 	// Switch to the logfile
 	if config.Logfile != "" {
 		f, err := os.OpenFile(