Term rework (Gallopsled#2242)

* term rework

* towards floating cells

* redraw when screen clears

* term: working completion

* Display non-printable characters

* ui: fix options with new term

* term: Clean up and fix examples/spinners

* changelog and lint

* Fix SSH in NOTERM mode

* defer termios setup

* term: py2 compat

* py2: compat fixup

* appease pylint

* fix scroll on winch

* term: fix hang on winch during readline

Author: Arusekk

CHANGELOG.md

@@ -70,12 +70,14 @@ The table below shows which release corresponds to each branch, and what date th
 
 ## 4.13.0 (`dev`)
 
+- [#2242][2242] Term module revamp: activating special handling of terminal only when necessary
 - [#2277][2277] elf: Resolve more relocations into GOT entries
 - [#2281][2281] FIX: Getting right amount of data for search fix
 - [#2293][2293] Add x86 CET status to checksec output
 - [#1763][1763] Allow to add to the existing environment in `process` instead of replacing it
 - [#2307][2307] Fix `pwn libcdb file` crashing if "/bin/sh" string was not found
 
+[2242]: https://github.com/Gallopsled/pwntools/pull/2242
 [2277]: https://github.com/Gallopsled/pwntools/pull/2277
 [2281]: https://github.com/Gallopsled/pwntools/pull/2281
 [2293]: https://github.com/Gallopsled/pwntools/pull/2293

examples/options.py

@@ -4,5 +4,5 @@
 
 from pwn import *
 
-opts = [string.letters[x] for x in range(10)]
+opts = [string.ascii_letters[x] for x in range(12)]
 print('You choose "%s"' % opts[options('Pick one:', opts)])

pwnlib/log.py

@@ -560,7 +560,7 @@ def emit(self, record):
 
         # we enrich the `Progress` object to keep track of the spinner
         if not hasattr(progress, '_spinner_handle'):
-            spinner_handle = term.output('')
+            spinner_handle = term.output('[x] ')
             msg_handle = term.output(msg)
             stop = threading.Event()
             def spin():

pwnlib/py2compat.py

@@ -0,0 +1,94 @@
+"""
+Compatibility layer with python 2, allowing us to write normal code.
+Beware, some monkey-patching is done.
+"""
+
+import os
+import shutil
+import sys
+try:
+    import fcntl
+    import termios
+except ImportError:
+    pass
+
+from collections import namedtuple
+from struct import Struct
+
+def py2_monkey_patch(module):
+    def decorator(f):
+        if sys.version_info < (3,):
+            f.__module__ = module.__name__
+            setattr(module, f.__name__, f)
+    return decorator
+
+# python3 -c 'import shutil,inspect; print(inspect.getsource(shutil.get_terminal_size))'
+@py2_monkey_patch(shutil)
+def get_terminal_size(fallback=(80, 24)):
+    """Get the size of the terminal window.
+
+    For each of the two dimensions, the environment variable, COLUMNS
+    and LINES respectively, is checked. If the variable is defined and
+    the value is a positive integer, it is used.
+
+    When COLUMNS or LINES is not defined, which is the common case,
+    the terminal connected to sys.__stdout__ is queried
+    by invoking os.get_terminal_size.
+
+    If the terminal size cannot be successfully queried, either because
+    the system doesn't support querying, or because we are not
+    connected to a terminal, the value given in fallback parameter
+    is used. Fallback defaults to (80, 24) which is the default
+    size used by many terminal emulators.
+
+    The value returned is a named tuple of type os.terminal_size.
+    """
+    # columns, lines are the working values
+    try:
+        columns = int(os.environ['COLUMNS'])
+    except (KeyError, ValueError):
+        columns = 0
+
+    try:
+        lines = int(os.environ['LINES'])
+    except (KeyError, ValueError):
+        lines = 0
+
+    # only query if necessary
+    if columns <= 0 or lines <= 0:
+        try:
+            size = os.get_terminal_size(sys.__stdout__.fileno())
+        except (AttributeError, ValueError, IOError):
+            # stdout is None, closed, detached, or not a terminal, or
+            # os.get_terminal_size() is unsupported
+            size = os.terminal_size(fallback)
+        if columns <= 0:
+            columns = size.columns
+        if lines <= 0:
+            lines = size.lines
+
+    return os.terminal_size((columns, lines))
+
+@py2_monkey_patch(os)
+class terminal_size(tuple):
+    @property
+    def columns(self):
+        return self[0]
+
+    @property
+    def lines(self):
+        return self[1]
+
+    def __repr__(self):
+        return 'os.terminal_size(columns=%r, lines=%r)' % self
+
+terminal_size = namedtuple('terminal_size', 'columns lines')
+
+termsize = Struct('HHHH')
+
+@py2_monkey_patch(os)
+def get_terminal_size(fd):  # pylint: disable=function-redefined
+    arr = b'\0' * termsize.size
+    arr = fcntl.ioctl(fd, termios.TIOCGWINSZ, arr)
+    lines, columns, xpixel, ypixel = termsize.unpack(arr)
+    return os.terminal_size((columns, lines))

pwnlib/term/__init__.py

@@ -12,9 +12,10 @@
 from pwnlib.term import text
 
 # Re-exports (XXX: Are these needed?)
-output = term.output
-width =  term.width
+term.update_geometry()
+width = term.width
 height = term.height
+output = term.output
 getkey = key.get
 Keymap = keymap.Keymap
 

pwnlib/term/key.py

@@ -10,6 +10,7 @@
 
 from pwnlib.term import keyconsts as kc
 from pwnlib.term import termcap
+from pwnlib.term import term
 
 __all__ = ['getch', 'getraw', 'get', 'unget']
 
@@ -25,7 +26,10 @@ def getch(timeout = 0):
         try:
             rfds, _wfds, _xfds = select.select([_fd], [], [], timeout)
             if rfds:
-                c = os.read(_fd, 1)
+                with term.rlock:
+                    rfds, _wfds, _xfds = select.select([_fd], [], [], 0)
+                    if not rfds: continue
+                    c = os.read(_fd, 1)
                 return ord(c) if c else None
             else:
                 return None

pwnlib/term/readline.py

@@ -3,6 +3,7 @@
 from __future__ import division
 from __future__ import print_function
 
+import io
 import six
 import sys
 
@@ -406,17 +407,20 @@ def readline(_size=-1, prompt='', float=True, priority=10):
                         history.insert(0, buffer)
                     return force_to_bytes(buffer)
             except KeyboardInterrupt:
-                control_c()
+                do_raise = False
+                try:
+                    control_c()
+                except KeyboardInterrupt:
+                    do_raise = True
+                if do_raise:
+                    raise
     finally:
         line = buffer_left + buffer_right + '\n'
         buffer_handle.update(line)
-        buffer_handle.freeze()
         buffer_handle = None
         if prompt_handle:
-            prompt_handle.freeze()
             prompt_handle = None
         if suggest_handle:
-            suggest_handle.freeze()
             suggest_handle = None
         if shutdown_hook:
             shutdown_hook()
@@ -484,7 +488,10 @@ class Wrapper:
         def __init__(self, fd):
             self._fd = fd
         def readline(self, size = None):
-            return readline(size)
+            r = readline(size)
+            if isinstance(self._fd, io.TextIOWrapper):
+                r = r.decode(encoding=self._fd.encoding, errors=self._fd.errors)
+            return r
         def __getattr__(self, k):
             return getattr(self._fd, k)
     sys.stdin = Wrapper(sys.stdin)