getty/login: add diagnostic logging to trace login prompt

src/bin/login.rs

@@ -2,10 +2,17 @@
 extern crate clap;
 
 use libredox::error::Result;
-use std::fs::File;
+use std::fs::{File, OpenOptions};
 use std::io::{self, Write};
 use std::str;
 
+fn dlog(msg: &str) {
+    let _ = OpenOptions::new()
+        .write(true)
+        .open("/scheme/debug/no-preserve")
+        .and_then(|mut f| writeln!(f, "LOGIN {}", msg));
+}
+
 use extra::option::OptionalExt;
 use redox_users::{All, AllUsers, Config, User};
 use termion::input::TermRead;
@@ -118,6 +125,7 @@ fn load_config_schemes(user: &User<redox_users::auth::Full>) -> Option<Vec<Strin
 }
 
 pub fn main() {
+    dlog("main started");
     let mut stdout = io::stdout();
     let mut stderr = io::stderr();
 
@@ -127,12 +135,20 @@ pub fn main() {
     )
     .get_matches();
 
+    dlog("before issue");
     if let Ok(mut issue) = File::open(ISSUE_FILE) {
         io::copy(&mut issue, &mut stdout).r#try(&mut stderr);
         stdout.flush().r#try(&mut stderr);
+        dlog("issue printed");
+    } else {
+        dlog("no issue file");
     }
 
     loop {
+        dlog("before liner read_line");
+        let _ = stdout.write_all(b"DIRECT_PROMPT_TEST");
+        let _ = stdout.flush();
+        dlog("direct prompt write done");
         let user = liner::Context::new()
             .read_line(
                 liner::Prompt::from("\x1B[1mRed Bear login:\x1B[0m "),
@@ -140,6 +156,7 @@ pub fn main() {
                 &mut liner::BasicCompleter::new(Vec::<String>::new()),
             )
             .r#try(&mut stderr);
+        dlog("after liner read_line");
 
         if !user.is_empty() {
             let stdin = io::stdin();