Fix pause module so it does not stack trace when redirecting stdout. (#42217)

* Use separate variables for stdin and stdout file descriptors

* Do not set stdout to raw mode when output is not a TTY

changelogs/fragments/pause-stdout-redirection.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - pause - do not set stdout to raw mode when redirecting to a file (https://github.com/ansible/ansible/issues/41717)

lib/ansible/plugins/action/pause.py

@@ -143,7 +143,7 @@ class ActionModule(ActionBase):
         result['start'] = to_text(datetime.datetime.now())
         result['user_input'] = b''
 
-        fd = None
+        stdin_fd = None
         old_settings = None
         try:
             if seconds is not None:
@@ -167,7 +167,8 @@ class ActionModule(ActionBase):
 
             # save the attributes on the existing (duped) stdin so
             # that we can restore them later after we set raw mode
-            fd = None
+            stdin_fd = None
+            stdout_fd = None
             try:
                 if PY3:
                     stdin = self._connection._new_stdin.buffer
@@ -175,52 +176,59 @@ class ActionModule(ActionBase):
                 else:
                     stdin = self._connection._new_stdin
                     stdout = sys.stdout
-                fd = stdin.fileno()
+                stdin_fd = stdin.fileno()
+                stdout_fd = stdout.fileno()
             except (ValueError, AttributeError):
                 # ValueError: someone is using a closed file descriptor as stdin
                 # AttributeError: someone is using a null file descriptor as stdin on windoez
                 stdin = None
 
-            if fd is not None:
-                if isatty(fd):
-
+            if stdin_fd is not None:
+                if isatty(stdin_fd):
                     # grab actual Ctrl+C sequence
                     try:
-                        intr = termios.tcgetattr(fd)[6][termios.VINTR]
+                        intr = termios.tcgetattr(stdin_fd)[6][termios.VINTR]
                     except Exception:
                         # unsupported/not present, use default
                         intr = b'\x03'  # value for Ctrl+C
 
                     # get backspace sequences
                     try:
-                        backspace = termios.tcgetattr(fd)[6][termios.VERASE]
+                        backspace = termios.tcgetattr(stdin_fd)[6][termios.VERASE]
                     except Exception:
                         backspace = [b'\x7f', b'\x08']
 
-                    old_settings = termios.tcgetattr(fd)
-                    tty.setraw(fd)
-                    tty.setraw(stdout.fileno())
+                    old_settings = termios.tcgetattr(stdin_fd)
+                    tty.setraw(stdin_fd)
+
+                    # Only set stdout to raw mode if it is a TTY. This is needed when redirecting
+                    # stdout to a file since a file cannot be set to raw mode.
+                    if isatty(stdout_fd):
+                        tty.setraw(stdout_fd)
 
                     # Only echo input if no timeout is specified
                     if not seconds and echo:
-                        new_settings = termios.tcgetattr(fd)
+                        new_settings = termios.tcgetattr(stdin_fd)
                         new_settings[3] = new_settings[3] | termios.ECHO
-                        termios.tcsetattr(fd, termios.TCSANOW, new_settings)
+                        termios.tcsetattr(stdin_fd, termios.TCSANOW, new_settings)
 
                     # flush the buffer to make sure no previous key presses
                     # are read in below
                     termios.tcflush(stdin, termios.TCIFLUSH)
 
             while True:
+
                 try:
-                    if fd is not None:
+                    if stdin_fd is not None:
+
                         key_pressed = stdin.read(1)
+
                         if key_pressed == intr:  # value for Ctrl+C
                             clear_line(stdout)
                             raise KeyboardInterrupt
 
                     if not seconds:
-                        if fd is None or not isatty(fd):
+                        if stdin_fd is None or not isatty(stdin_fd):
                             display.warning("Not waiting for response to prompt as stdin is not interactive")
                             break
 
@@ -255,9 +263,9 @@ class ActionModule(ActionBase):
             pass
         finally:
             # cleanup and save some information
-            # restore the old settings for the duped stdin fd
-            if not(None in (fd, old_settings)) and isatty(fd):
-                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
+            # restore the old settings for the duped stdin stdin_fd
+            if not(None in (stdin_fd, old_settings)) and isatty(stdin_fd):
+                termios.tcsetattr(stdin_fd, termios.TCSADRAIN, old_settings)
 
             duration = time.time() - start
             result['stop'] = to_text(datetime.datetime.now())

test/integration/targets/pause/runme.sh

@@ -15,6 +15,12 @@ ansible-playbook test-pause-no-tty.yml -i ../../inventory 2>&1 | \
     }
 EOF
 
+# Test redirecting stdout
+# Issue #41717
+ansible-playbook pause-3.yml -i ../../inventory > /dev/null \
+    && echo "Successfully redirected stdout" \
+    || echo "Failure when attempting to redirect stdout"
+
 # Test pause with seconds and minutes specified
 ansible-playbook test-pause.yml -i ../../inventory "$@"