Revert "su: allocate new pty (#1693)"

This reverts commit 935dc18faa.

userspace/ksud/src/su.rs

@@ -11,8 +11,6 @@ use crate::{
     utils::{self, umask},
 };
 
-#[cfg(any(target_os = "linux", target_os = "android"))]
-use crate::pty::prepare_pty;
 #[cfg(any(target_os = "linux", target_os = "android"))]
 use rustix::{
     process::getuid,
@@ -140,7 +138,6 @@ pub fn root_shell() -> Result<()> {
         "Specify a supplementary group. The first specified supplementary group is also used as a primary group if the option -g is not specified.",
         "GROUP",
     );
-    opts.optflag("", "no-pty", "Do not allocate a new pseudo terminal.");
 
     // Replace -cn with -z, -mm with -M for supporting getopt_long
     let args = args
@@ -268,13 +265,6 @@ pub fn root_shell() -> Result<()> {
         command = command.env("ENV", defs::KSURC_PATH);
     }
 
-    #[cfg(target_os = "android")]
-    if !matches.opt_present("no-pty") {
-        if let Err(e) = prepare_pty() {
-            log::error!("failed to prepare pty: {:?}", e);
-        }
-    }
-
     // escape from the current cgroup and become session leader
     // WARNING!!! This cause some root shell hang forever!
     // command = command.process_group(0);