Fix wrong tty pump

See #1463

native/src/core/lib.rs

@@ -16,7 +16,7 @@ use logging::{android_logging, setup_logfile, zygisk_close_logd, zygisk_get_logd
 use mount::{find_preinit_device, revert_unmount};
 use resetprop::{persist_delete_prop, persist_get_prop, persist_get_props, persist_set_prop};
 use socket::{recv_fd, recv_fds, send_fd, send_fds};
-use su::{pump_stdin_stdout, get_pty_num, restore_stdin};
+use su::{pump_tty, get_pty_num, restore_stdin};
 use std::fs::File;
 use std::mem::ManuallyDrop;
 use std::ops::DerefMut;
@@ -209,7 +209,7 @@ pub mod ffi {
         #[namespace = "rust"]
         fn daemon_entry();
 
-        fn pump_stdin_stdout(infd: i32, outfd: i32);
+        fn pump_tty(infd: i32, outfd: i32);
         fn get_pty_num(fd: i32) -> i32;
         fn restore_stdin() -> bool;
     }

native/src/core/su/mod.rs

@@ -3,4 +3,4 @@ mod db;
 mod pts;
 
 pub use daemon::SuInfo;
-pub use pts::{pump_stdin_stdout, get_pty_num, restore_stdin};
+pub use pts::{pump_tty, get_pty_num, restore_stdin};

native/src/core/su/pts.rs

@@ -28,10 +28,14 @@ fn set_stdin_raw() -> bool {
             return false;
         }
 
+        let old_c_oflag = termios.c_oflag;
         OLD_STDIN = Some(termios);
 
         cfmakeraw(&mut termios);
 
+        // don't modify output flags, since we are not setting stdout raw
+        termios.c_oflag = old_c_oflag;
+
         if tcsetattr(STDIN_FILENO, TCSAFLUSH, &termios) < 0
             && tcsetattr(STDIN_FILENO, TCSADRAIN, &termios) < 0
         {
@@ -65,7 +69,7 @@ fn resize_pty(outfd: i32) {
     }
 }
 
-pub fn pump_stdin_stdout(infd: i32, outfd: i32) {
+pub fn pump_tty(infd: i32, outfd: i32) {
     set_stdin_raw();
 
     let sfd = unsafe {
@@ -82,7 +86,7 @@ pub fn pump_stdin_stdout(infd: i32, outfd: i32) {
 
     let mut pfds = [
         pollfd {
-            fd: STDIN_FILENO,
+            fd: if outfd > 0 { STDIN_FILENO } else { -1 },
             events: POLLIN,
             revents: 0,
         },

native/src/core/su/su.cpp

@@ -239,7 +239,9 @@ int su_client_main(int argc, char *argv[]) {
 
     if (atty) {
         setup_sighandlers(sighandler);
-        pump_stdin_stdout(ptmx, ptmx);
+        // if stdin is not a tty, if we pump to ptmx, our process may intercept the input to ptmx and
+        // output to stdout, which cause the target process lost input.
+        pump_tty(ptmx, (atty & ATTY_IN) ? ptmx : -1);
     }
 
     // Get the exit code