From 58f67c1ccbe6391aec6508c3f8cd72513220b8ad Mon Sep 17 00:00:00 2001
From: Drew Stratford <drewstratford@outlook.com>
Date: Sun, 20 Oct 2019 20:02:55 +1300
Subject: [PATCH] Shell: Update termios settings to match line discipline.

Shell.cpp uses its own line discipline which handles
echoing and line editing. Because of this we disable
ICANON and ECHO so that we don't get duplicate characters
or weird line editing errors.

We also revert these settings just before running a command.
This is so that commands may run with proper line editing
and echoing.
---
 Shell/GlobalState.h | 1 +
 Shell/main.cpp      | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Shell/GlobalState.h b/Shell/GlobalState.h
index e92dd8df3e2..645652f4ac4 100644
--- a/Shell/GlobalState.h
+++ b/Shell/GlobalState.h
@@ -13,6 +13,7 @@ struct GlobalState {
     pid_t sid;
     uid_t uid;
     struct termios termios;
+    struct termios default_termios;
     bool was_interrupted { false };
     bool was_resized { false };
     int last_return_code { 0 };
diff --git a/Shell/main.cpp b/Shell/main.cpp
index 28b4a3519fe..2dc62b07028 100644
--- a/Shell/main.cpp
+++ b/Shell/main.cpp
@@ -634,6 +634,7 @@ static int run_command(const String& cmd)
 
     struct termios trm;
     tcgetattr(0, &trm);
+    tcsetattr(0, TCSANOW, &g.default_termios);
 
     struct SpawnedProcess {
         String name;
@@ -840,7 +841,12 @@ int main(int argc, char** argv)
     g.uid = getuid();
     g.sid = setsid();
     tcsetpgrp(0, getpgrp());
-    tcgetattr(0, &g.termios);
+    tcgetattr(0, &g.default_termios);
+    g.termios = g.default_termios;
+    // Because we use our own line discipline which includes echoing,
+    // we disable ICANON and ECHO.
+    g.termios.c_lflag &= ~(ECHO | ICANON);
+    tcsetattr(0, TCSANOW, &g.termios);
 
     signal(SIGINT, [](int) {
         g.was_interrupted = true;