fix finding the active tty name

apparently $TTY is a shell builtin variable, and not set in the actual
environment

1 files changed, 26 insertions, 5 deletions

diff --git a/src/bin/rbw/actions.rs b/src/bin/rbw/actions.rs
index 035ebe6..8eabdd6 100644
--- a/src/bin/rbw/actions.rs
+++ b/src/bin/rbw/actions.rs
@@ -25,7 +25,7 @@ pub fn quit() -> anyhow::Result<()> {
             std::fs::File::open(pidfile)?.read_to_string(&mut pid)?;
             let pid = nix::unistd::Pid::from_raw(pid.parse()?);
             sock.send(&rbw::protocol::Request {
-                tty: std::env::var("TTY").ok(),
+                tty: ttyname(),
                 action: rbw::protocol::Action::Quit,
             })?;
             wait_for_exit(pid)?;
@@ -48,7 +48,7 @@ pub fn decrypt(
     let mut sock = crate::sock::Sock::connect()
         .context("failed to connect to rbw-agent")?;
     sock.send(&rbw::protocol::Request {
-        tty: std::env::var("TTY").ok(),
+        tty: ttyname(),
         action: rbw::protocol::Action::Decrypt {
             cipherstring: cipherstring.to_string(),
             org_id: org_id.map(std::string::ToString::to_string),
@@ -72,7 +72,7 @@ pub fn encrypt(
     let mut sock = crate::sock::Sock::connect()
         .context("failed to connect to rbw-agent")?;
     sock.send(&rbw::protocol::Request {
-        tty: std::env::var("TTY").ok(),
+        tty: ttyname(),
         action: rbw::protocol::Action::Encrypt {
             plaintext: plaintext.to_string(),
             org_id: org_id.map(std::string::ToString::to_string),
@@ -93,7 +93,7 @@ pub fn version() -> anyhow::Result<u32> {
     let mut sock = crate::sock::Sock::connect()
         .context("failed to connect to rbw-agent")?;
     sock.send(&rbw::protocol::Request {
-        tty: std::env::var("TTY").ok(),
+        tty: ttyname(),
         action: rbw::protocol::Action::Version,
     })?;
 
@@ -112,7 +112,7 @@ fn simple_action(action: rbw::protocol::Action) -> anyhow::Result<()> {
         .context("failed to connect to rbw-agent")?;
 
     sock.send(&rbw::protocol::Request {
-        tty: std::env::var("TTY").ok(),
+        tty: ttyname(),
         action,
     })?;
 
@@ -126,6 +126,27 @@ fn simple_action(action: rbw::protocol::Action) -> anyhow::Result<()> {
     }
 }
 
+// TODO: it'd be great if ttyname_r was exposed via nix, so i didn't have to
+// manually deal with unsafe here
+fn ttyname() -> Option<String> {
+    const PATH_MAX: usize = libc::PATH_MAX as usize;
+    let mut buf = [0_u8; PATH_MAX];
+    let c_buf = buf.as_mut_ptr() as *mut libc::c_char;
+
+    let ret = unsafe { libc::ttyname_r(0, c_buf, PATH_MAX) };
+    if ret != 0 {
+        return None;
+    }
+
+    let nul = memchr::memchr(b'\0', &buf)?;
+    if nul == 0 {
+        return None;
+    }
+
+    let s = std::str::from_utf8(&buf[..nul]).ok()?;
+    Some(s.to_string())
+}
+
 fn wait_for_exit(pid: nix::unistd::Pid) -> anyhow::Result<()> {
     loop {
         if nix::sys::signal::kill(pid, None).is_err() {