Slight protocol change, docs

README.md

@@ -4,21 +4,26 @@ Generic display manager. Composed of a daemon which:
 
 1. Launches a greeter of your choice.
 2. Listens on a socket for a login message.
-3. If the credentials are valid, terminates the greeter and starts the requested session application.
+3. If the credentials are valid, terminates the greeter (if it didn't do so itself) and starts the requested session application.
 4. When the session application terminates, the greeter is started once again.
 
 All the greeter of choice needs to do is to be able to write a message to a socket. It could be anything from a simple terminal application to a fully-fledged desktop environment in which one of the applications present a user prompt.
 
 The greeter runs as a configured user, which is supposed to be one with no interesting privileges except for what the greeter itself needs to run.
 
-Future plans involve adding lock-screen support.
-
-Protocol subject to change soon.
-
 ## Included in the box:
 
-1. greetd, the daemon itself
-2. greetctl, a sample application to issue the login message.
+### Binaries
+
+- greetd, the daemon itself
+- greetctl, a sample application to issue the login message.
+- greet_proto, a protocol library in Rust. Don't worry if you don't use Rust, the protocol is very simple.
+
+### Configuration files
+
+- greeter.pam, a PAM service file that should be put as `/etc/pam.d/greeter`
+- config.toml, a configuration file example
+- greetd.service, a systemd service file example.
 
 ## Dumb demo
 
@@ -27,6 +32,56 @@ Protocol subject to change soon.
 3. (In the new terminal): greetctl
 4. Answer the questions, and the sway greeter will be replaced by whatever you typed if your login is successful.
 
-## It doesn't work yet!
+## Other greeters
 
-Why are you using this? I haven't even tested it myself!
+- dlm - Dumb Login Manager
+- wlgreet - Wayland greeter
+
+# Protocol
+
+```
+ ________________________________________________________
+|           |             |                    |         |
+| magic u32 | version u32 | payload_length u32 | payload |
+|___________|_____________|____________________|_________|
+```
+
+Magic is always `0xAFBFCFDF`, version is `1`, payload is JSON.
+
+Requests and responses are encoded the same.
+
+## Requests
+
+### Login
+
+```
+{
+	"type": "login",
+	"username": "user",
+	"password": "password",
+	"command": ["sway"],
+	"env": {
+		"XDG_SESSION_TYPE": "wayland",
+		"XDG_SESSION_DESKTOP": "sway",
+	}
+}
+```
+
+## Response
+
+### Success
+
+```
+{
+	"type": "success",
+}
+```
+
+### Login error
+
+```
+{
+	"type": "loginError",
+	"description": "..."
+}
+```

config.toml

@@ -0,0 +1,3 @@
+vt = 2
+greeter = "dlm"
+greeter_user = "greeter"

greet_proto/src/lib.rs

@@ -74,8 +74,10 @@ impl Request {
 #[derive(Debug, Deserialize, Serialize)]
 #[serde(tag = "type")]
 pub enum Response {
-    LoginSuccess,
-    LoginFailure,
+    Success,
+    LoginError {
+        description: String
+    },
 }
 
 impl Response {

greetctl/src/main.rs

@@ -44,9 +44,9 @@ fn login() -> Result<(), Box<dyn std::error::Error>> {
     let resp = Response::from_slice(&resp_buf)?;
 
     match resp {
-        Response::LoginSuccess => Ok(()),
-        Response::LoginFailure => {
-            Err(std::io::Error::new(io::ErrorKind::Other, "authentication failed").into())
+        Response::Success => Ok(()),
+        Response::LoginError { description } => {
+            Err(std::io::Error::new(io::ErrorKind::Other, format!("login error: {}", description)).into())
         }
     }
 }

greetd.service

@@ -4,13 +4,8 @@ After=systemd-user-sessions.service plymouth-quit-wait.service
 After=getty@tty2.service
 
 [Service]
-Type=idle
-ExecStart=/usr/local/bin/greetd --vt=2 --greeter=dlm --greeteruser=greeter
-StandardInput=tty
-StandardError=syslog
-TTYPath=/dev/tty2
-TTYReset=yes
-TTYVHangup=yes
+Type=simple
+ExecStart=greetd
 Restart=always
 
 [Install]

greetd/src/client.rs

@@ -102,8 +102,8 @@ impl Pollable for Client {
                                     self.buf.scramble();
 
                                     let resp = match ctx.login(username, password, command, env) {
-                                        Ok(_) => Response::LoginSuccess,
-                                        Err(_) => Response::LoginFailure,
+                                        Ok(_) => Response::Success,
+                                        Err(e) => Response::LoginError{ description: format!("{}", e) },
                                     };
 
                                     let resp_bytes =