Add support for execing the user's Python program

4 files changed, 97 insertions, 11 deletions

diff --git a/python/interpreter.py b/python/interpreter.py
index 87de3aa..3439ae8 100755
--- a/python/interpreter.py
+++ b/python/interpreter.py
@@ -7,9 +7,13 @@ import seccomp
 
 f = seccomp.SyscallFilter(defaction=seccomp.KILL)
 # Necessary for Python.
+f.add_rule(seccomp.ALLOW, "brk")
 f.add_rule(seccomp.ALLOW, "exit_group")
+f.add_rule(seccomp.ALLOW, "ioctl")
+f.add_rule(seccomp.ALLOW, "mmap")
+f.add_rule(seccomp.ALLOW, "munmap")
 f.add_rule(seccomp.ALLOW, "rt_sigaction")
-f.add_rule(seccomp.ALLOW, "brk")
+f.add_rule(seccomp.ALLOW, "rt_sigreturn")
 
 # Mostly harmless.
 f.add_rule(seccomp.ALLOW, "mprotect")
@@ -19,22 +23,59 @@ f.add_rule(seccomp.ALLOW, "read", seccomp.Arg(0, seccomp.EQ, sys.stdin.fileno())
 f.add_rule(seccomp.ALLOW, "write", seccomp.Arg(0, seccomp.EQ, sys.stdout.fileno()))
 f.add_rule(seccomp.ALLOW, "write", seccomp.Arg(0, seccomp.EQ, sys.stderr.fileno()))
 
-f.add_rule(seccomp.ALLOW, "ioctl")
-f.add_rule(seccomp.ALLOW, "mmap")
-f.add_rule(seccomp.ALLOW, "munmap")
-
 # Needed for finding source code for exceptions.
 f.add_rule(seccomp.ALLOW, "stat")
+# Read-only open.
 f.add_rule(seccomp.ALLOW, "open", seccomp.Arg(1, seccomp.MASKED_EQ, 0x3, 0))
-f.add_rule(seccomp.ALLOW, "fcntl")
+f.add_rule(seccomp.ALLOW, "close")
+f.add_rule(seccomp.ALLOW, "read")
 f.add_rule(seccomp.ALLOW, "fstat")
 f.add_rule(seccomp.ALLOW, "lseek")
-f.add_rule(seccomp.ALLOW, "read")
-f.add_rule(seccomp.ALLOW, "close")
+f.add_rule(seccomp.ALLOW, "fcntl")
 
 # Needed for code.InteractiveConsole.
 f.add_rule(seccomp.ALLOW, "access")
 f.add_rule(seccomp.ALLOW, "select")
 f.load()
 
-code.interact(banner='')
+class MyConsole(code.InteractiveConsole):
+    def interact(self, banner=None):
+        if banner is not None:
+            self.write('{}\n'.format(banner))
+
+        buffer = []
+        prompt = '>>> '
+        while True:
+            try:
+                line = input(prompt)
+                # Assume we are running the user's program; silence the prompt.
+                if line == 'exec("""\\':
+                    self.write('<run>\n')
+                    prompt = ''
+
+                buffer.append(line)
+                source = '\n'.join(buffer)
+                more = self.runsource(source)
+                if more:
+                    if prompt:
+                        prompt = '... '
+                else:
+                    prompt = '>>> '
+                    buffer = []
+            except KeyboardInterrupt:
+                prompt = '>>> '
+                buffer = []
+                self.write('^C\n')
+            except EOFError:
+                break
+
+    def runcode(self, code):
+        try:
+            exec(code, self.locals)
+        except KeyboardInterrupt:
+            # Don't show traceback on SIGINT.
+            raise
+        except:
+            self.showtraceback()
+
+MyConsole().interact()
diff --git a/server/handlers.py b/server/handlers.py
index 52a33f5..08994a0 100644
--- a/server/handlers.py
+++ b/server/handlers.py
@@ -106,7 +106,27 @@ class Query(CodeqService):
                 request.reply(result)
 
 
-# Push stdin to the session's Python interpreter. TODO: convert to async handling
+# Push user program to the Python interpreter to be exec'd.
+class PythonExec(CodeqService):
+    def process(self, request):
+        program = request.data.get('program')
+        if program is None:
+            request.reply({'code': 1, 'message': 'No program specified'})
+        else:
+            python = request.session.get_python()
+            python.exec(program)
+            request.reply({'code': 0, 'message': 'ok'})
+
+
+# Send an interrupt to the Python interpreter.
+class PythonStop(CodeqService):
+    def process(self, request):
+        python = request.session.get_python()
+        python.stop()
+        request.reply({'code': 0, 'message': 'ok'})
+
+
+# Push stdin to the Python interpreter.
 class PythonPush(CodeqService):
     def process(self, request):
         text = request.data.get('text')
@@ -194,7 +214,9 @@ incoming_handlers = {
     'logout': None,
     'activity': Activity(),
     'query': Query(),
+    'python_exec': PythonExec(),
     'python_push': PythonPush(),
+    'python_stop': PythonStop(),
     'hint': Hint(),
     'test': Test()
 }
diff --git a/server/python_session.py b/server/python_session.py
index 62fcbf8..6f2c999 100644
--- a/server/python_session.py
+++ b/server/python_session.py
@@ -6,6 +6,7 @@ import io
 import multiprocessing
 import os
 import queue
+import signal
 import subprocess
 import sys
 import threading
@@ -55,9 +56,15 @@ class PythonSession(object):
             p.terminate()
         return results
 
+    def exec(self, program):
+        self._control.put_nowait(('exec', program))
+
     def push(self, stdin):
         self._control.put_nowait(('push', stdin))
 
+    def stop(self):
+        self._control.put_nowait(('stop', None))
+
     def destroy(self):
         self._control.put_nowait(('done', None))
 
@@ -125,9 +132,15 @@ def _interpreter(control, callback):
         # Get a control command.
         try:
             cmd, data = control.get_nowait()
-            if cmd == 'push':
+            if cmd == 'exec':
+                exec_str = 'exec("""\\\n{}\n""")\n'.format(data.replace('"', '\\"'))
+                proc.stdin.write(exec_str.encode('utf-8'))
+                proc.stdin.flush()
+            elif cmd == 'push':
                 proc.stdin.write(data.encode('utf-8'))
                 proc.stdin.flush()
+            elif cmd == 'stop':
+                proc.send_signal(signal.SIGINT)
             elif cmd == 'done':
                 break
         except:
diff --git a/web/main.js b/web/main.js
index 03e9dad..fb393c8 100644
--- a/web/main.js
+++ b/web/main.js
@@ -132,11 +132,21 @@ var guiHandlers = {
         sendDataToPython(message).then(session.send, session.end).done();
     },
 
+    'python_exec': function actionPythonExec(session, message) {
+        logger.debug('Received python_exec from GUI');
+        sendDataToPython(message).then(session.send, session.end).done();
+    },
+
     'python_push': function actionPythonPush(session, message) {
         logger.debug('Received python_push from GUI');
         sendDataToPython(message).then(session.send, session.end).done();
     },
 
+    'python_stop': function actionPythonStop(session, message) {
+        logger.debug('Received python_stop from GUI');
+        sendDataToPython(message).then(session.send, session.end).done();
+    },
+
     'hint': function actionHint(session, message) {
         logger.debug('Received hint from GUI');
         sendDataToPython(message).then(session.send, session.end).done();