Hide macOS login message with ~/.hushlogin present

On macOS every shell is a login shell, which will always print
information about the last login when the terminal is started. The macOS
standard for disabling this is to place a `.hushlogin` file in the
user's home directory, but this did not work with Alacritty since
`login` only looks for this file in the current directory.

To ensure the login message is properly suppressed, Alacritty's default
shell will now check for the presence of the `.hushlogin` file in the
user's home directory and append `-q` to the `login` arguments if it is
present, which will behave as if a `.hushlogin` file was found by
`login`.

Co-authored-by: Thomas <thomas@zed.dev>
Co-authored-by: Anthony <anthony@zed.dev>

3 files changed, 22 insertions, 4 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 49984568..cf13eb7a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,10 @@ Notable changes to the `alacritty_terminal` crate are documented in its
 
 ## 0.16.0-dev
 
+### Changed
+
+- Hide login message if `~/.hushlogin` is present
+
 ### Fixed
 
 - Crash when OpenGL context resets
diff --git a/alacritty_terminal/CHANGELOG.md b/alacritty_terminal/CHANGELOG.md
index 90f300f7..9b2f9ebf 100644
--- a/alacritty_terminal/CHANGELOG.md
+++ b/alacritty_terminal/CHANGELOG.md
@@ -10,6 +10,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## 0.25.1-dev
 
+### Changed
+
+- Pass `-q` to `login` on macOS if `~/.hushlogin` is present
+
 ## 0.25.0
 
 ### Changed
diff --git a/alacritty_terminal/src/tty/unix.rs b/alacritty_terminal/src/tty/unix.rs
index e3db51fb..884cb5c1 100644
--- a/alacritty_terminal/src/tty/unix.rs
+++ b/alacritty_terminal/src/tty/unix.rs
@@ -8,6 +8,8 @@ use std::os::fd::OwnedFd;
 use std::os::unix::io::AsRawFd;
 use std::os::unix::net::UnixStream;
 use std::os::unix::process::CommandExt;
+#[cfg(target_os = "macos")]
+use std::path::Path;
 use std::process::{Child, Command};
 use std::sync::Arc;
 use std::{env, ptr};
@@ -158,12 +160,12 @@ impl ShellUser {
 }
 
 #[cfg(not(target_os = "macos"))]
-fn default_shell_command(shell: &str, _user: &str) -> Command {
+fn default_shell_command(shell: &str, _user: &str, _home: &str) -> Command {
     Command::new(shell)
 }
 
 #[cfg(target_os = "macos")]
-fn default_shell_command(shell: &str, user: &str) -> Command {
+fn default_shell_command(shell: &str, user: &str, home: &str) -> Command {
     let shell_name = shell.rsplit('/').next().unwrap();
 
     // On macOS, use the `login` command so the shell will appear as a tty session.
@@ -173,12 +175,20 @@ fn default_shell_command(shell: &str, user: &str) -> Command {
     // `login` normally does this itself, but `-l` disables this.
     let exec = format!("exec -a -{} {}", shell_name, shell);
 
+    // Since we use -l, `login` will not change directory to the user's home. However,
+    // `login` only checks the current working directory for a .hushlogin file, causing
+    // it to miss any in the user's home directory. We can fix this by doing the check
+    // ourselves and passing `-q`
+    let has_home_hushlogin = Path::new(home).join(".hushlogin").exists();
+
     // -f: Bypasses authentication for the already-logged-in user.
     // -l: Skips changing directory to $HOME and prepending '-' to argv[0].
     // -p: Preserves the environment.
+    // -q: Act as if `.hushlogin` exists.
     //
     // XXX: we use zsh here over sh due to `exec -a`.
-    login_command.args(["-flp", user, "/bin/zsh", "-fc", &exec]);
+    let flags = if has_home_hushlogin { "-qflp" } else { "-flp" };
+    login_command.args([flags, user, "/bin/zsh", "-fc", &exec]);
     login_command
 }
 
@@ -208,7 +218,7 @@ pub fn from_fd(config: &Options, window_id: u64, master: OwnedFd, slave: OwnedFd
         cmd.args(shell.args.as_slice());
         cmd
     } else {
-        default_shell_command(&user.shell, &user.user)
+        default_shell_command(&user.shell, &user.user, &user.home)
     };
 
     // Setup child stdin/stdout/stderr as slave fd of PTY.