python · JarryShaw · Sep 24, 2018
diff --git a/Lib/pty.py b/Lib/pty.py
@@ -8,6 +8,8 @@

 from select import select
 import os
+import shutil
+import subprocess
 import tty

 __all__ = ["openpty","fork","spawn"]
@@ -18,6 +20,9 @@

 CHILD = 0

+PS_PATH = shutil.which('ps')
+TIMEOUT = None if PS_PATH is None else 1
+
 def openpty():
    """openpty() -> (master_fd, slave_fd)
    Open a pty master/slave pair, using os.openpty() if possible."""
@@ -126,14 +131,30 @@ def _read(fd):
    """Default read function."""
    return os.read(fd, 1024)

-def _copy(master_fd, master_read=_read, stdin_read=_read):
+def _is_zombie(pid):
+    """Check if pid is in zombie stat."""
+    if PS_PATH is None:
+        return False
+    try:
+        proc = subprocess.check_output([PS_PATH, 'axo', 'pid=,stat='])
+    except subprocess.CalledProcessError:
+        return False
+    for line in proc.splitlines():
+        _pid, stat = line.strip().decode().split()
+        if int(_pid) == pid:
+            return (stat == 'Z')
+    raise OSError(3, 'No such process')
+
+def _copy(pid, master_fd, master_read=_read, stdin_read=_read):
    """Parent copy loop.
    Copies
            pty master -> standard output   (master_read)
            standard input -> pty master    (stdin_read)"""
    fds = [master_fd, STDIN_FILENO]
    while True:
-        rfds, wfds, xfds = select(fds, [], [])
+        rfds, wfds, xfds = select(fds, [], [], TIMEOUT)
+        if _is_zombie(pid):
+            raise OSError(5, 'Input/output error')
        if master_fd in rfds:
            data = master_read(master_fd)
            if not data:  # Reached EOF.
@@ -161,7 +182,8 @@ def spawn(argv, master_read=_read, stdin_read=_read):
    except tty.error:    # This is the same as termios.error
        restore = 0
    try:
-        _copy(master_fd, master_read, stdin_read)
+        _copy(pid, master_fd, master_read, stdin_read)
+        # print('copied!')
    except OSError:
        if restore:
            tty.tcsetattr(STDIN_FILENO, tty.TCSAFLUSH, mode)