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

* Use separate variables for stdin and stdout file descriptors

* Do not set stdout to raw mode when output is not a TTY
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samdoran authored Jul 6, 2018
1 parent 39ec12f commit 1d1595b
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Showing 3 changed files with 34 additions and 18 deletions.
2 changes: 2 additions & 0 deletions changelogs/fragments/pause-stdout-redirection.yaml
Original file line number Diff line number Diff line change
@@ -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)
44 changes: 26 additions & 18 deletions lib/ansible/plugins/action/pause.py
Original file line number Diff line number Diff line change
Expand Up @@ -143,7 +143,7 @@ def run(self, tmp=None, task_vars=None):
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:
Expand All @@ -167,60 +167,68 @@ def run(self, tmp=None, task_vars=None):

# 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
stdout = sys.stdout.buffer
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

Expand Down Expand Up @@ -255,9 +263,9 @@ def run(self, tmp=None, task_vars=None):
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())
Expand Down
6 changes: 6 additions & 0 deletions test/integration/targets/pause/runme.sh
Original file line number Diff line number Diff line change
Expand Up @@ -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 "$@"

Expand Down

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