Kills stray processes in code, hook and stdio evaluator

7 files changed, 25 insertions, 10 deletions

diff --git a/requirements/requirements-common.txt b/requirements/requirements-common.txt
index e04c5bd..53a44a4 100644
--- a/requirements/requirements-common.txt
+++ b/requirements/requirements-common.txt
@@ -5,3 +5,4 @@ python-social-auth==0.2.19
 tornado
 selenium==2.53.6
 coverage
+psutil
diff --git a/yaksh/base_evaluator.py b/yaksh/base_evaluator.py
index 071008f..653aef0 100644
--- a/yaksh/base_evaluator.py
+++ b/yaksh/base_evaluator.py
@@ -7,6 +7,7 @@ from os.path import join, isfile
 from os.path import isdir, dirname, abspath, join, isfile, exists
 import subprocess
 import stat
+import signal
 
 
 # Local imports
@@ -30,11 +31,11 @@ class BaseEvaluator(object):
         stdout and stderr.
         """
         try:
-            proc = subprocess.Popen(cmd_args, *args, **kw)
+            proc = subprocess.Popen(cmd_args,preexec_fn=os.setpgrp, *args, **kw)
             stdout, stderr = proc.communicate()
         except TimeoutException:
             # Runaway code, so kill it.
-            proc.kill()
+            os.killpg(os.getpgid(proc.pid), signal.SIGTERM)
             # Re-raise exception.
             raise
         return proc, stdout.decode('utf-8'), stderr.decode('utf-8')
diff --git a/yaksh/bash_stdio_evaluator.py b/yaksh/bash_stdio_evaluator.py
index 334620d..1ce729a 100644
--- a/yaksh/bash_stdio_evaluator.py
+++ b/yaksh/bash_stdio_evaluator.py
@@ -49,7 +49,8 @@ class BashStdIOEvaluator(StdIOEvaluator):
                                 shell=True,
                                 stdin=subprocess.PIPE,
                                 stdout=subprocess.PIPE,
-                                stderr=subprocess.PIPE
+                                stderr=subprocess.PIPE,
+                                preexec_fn=os.setpgrp
                                 )
         success, err = self.evaluate_stdio(self.user_answer, proc,
                                            self.expected_input,
diff --git a/yaksh/cpp_stdio_evaluator.py b/yaksh/cpp_stdio_evaluator.py
index b302fa4..d211bb7 100644
--- a/yaksh/cpp_stdio_evaluator.py
+++ b/yaksh/cpp_stdio_evaluator.py
@@ -82,7 +82,8 @@ class CppStdIOEvaluator(StdIOEvaluator):
                                         shell=True,
                                         stdin=subprocess.PIPE,
                                         stdout=subprocess.PIPE,
-                                        stderr=subprocess.PIPE
+                                        stderr=subprocess.PIPE,
+                                        preexec_fn=os.setpgrp
                                         )
                 success, err = self.evaluate_stdio(self.user_answer, proc,
                                                    self.expected_input,
diff --git a/yaksh/hook_evaluator.py b/yaksh/hook_evaluator.py
index 0819ec9..b86640c 100644
--- a/yaksh/hook_evaluator.py
+++ b/yaksh/hook_evaluator.py
@@ -7,7 +7,8 @@ import os
 from .file_utils import copy_files, delete_files
 from .base_evaluator import BaseEvaluator
 from .grader import TimeoutException
-
+import signal
+import psutil
 
 class HookEvaluator(BaseEvaluator):
     def __init__(self, metadata, test_case_data):
@@ -65,10 +66,12 @@ class HookEvaluator(BaseEvaluator):
             check = hook_scope["check_answer"]
             success, err, mark_fraction = check(self.user_answer)
         except TimeoutException:
+            processes = psutil.Process(os.getpid()).children(recursive=True)
+            for process in processes:
+                process.kill()
             raise
         except Exception:
             msg = traceback.format_exc(limit=0)
             err = "Error in Hook code: {0}".format(msg)
         del tb
         return success, err, mark_fraction
- 
\ No newline at end of file
diff --git a/yaksh/java_stdio_evaluator.py b/yaksh/java_stdio_evaluator.py
index 48f265d..4e9238f 100644
--- a/yaksh/java_stdio_evaluator.py
+++ b/yaksh/java_stdio_evaluator.py
@@ -67,7 +67,8 @@ class JavaStdIOEvaluator(StdIOEvaluator):
                                     shell=True,
                                     stdin=subprocess.PIPE,
                                     stdout=subprocess.PIPE,
-                                    stderr=subprocess.PIPE
+                                    stderr=subprocess.PIPE,
+                                    preexec_fn=os.setpgrp
                                     )
             success, err = self.evaluate_stdio(self.user_answer, proc,
                                                self.expected_input,
diff --git a/yaksh/stdio_evaluator.py b/yaksh/stdio_evaluator.py
index fa78a68..ec69851 100644
--- a/yaksh/stdio_evaluator.py
+++ b/yaksh/stdio_evaluator.py
@@ -2,6 +2,9 @@ from __future__ import unicode_literals
 
 # Local imports
 from .base_evaluator import BaseEvaluator
+from .grader import TimeoutException
+import os
+import signal
 
 
 class StdIOEvaluator(BaseEvaluator):
@@ -9,9 +12,13 @@ class StdIOEvaluator(BaseEvaluator):
         success = False
         ip = expected_input.replace(",", " ")
         encoded_input = '{0}\n'.format(ip).encode('utf-8')
-        user_output_bytes, output_err_bytes = proc.communicate(encoded_input)
-        user_output = user_output_bytes.decode('utf-8')
-        output_err = output_err_bytes.decode('utf-8')
+        try:
+            user_output_bytes, output_err_bytes = proc.communicate(encoded_input)
+            user_output = user_output_bytes.decode('utf-8')
+            output_err = output_err_bytes.decode('utf-8')
+        except TimeoutException:
+            os.killpg(os.getpgid(proc.pid), signal.SIGTERM)
+            raise
         expected_output = expected_output.replace("\r", "")
         if not expected_input:
             error_msg = "Expected Output is\n{0} ".\