stdlib.run: Fix missing executable

leapp/libraries/stdlib/__init__.py

@@ -3,11 +3,11 @@
 represents a location for functions that otherwise would be defined multiple times across leapp actors
 and at the same time, they are really useful for other actors.
 """
+import base64
 import logging
 import os
 import sys
 import uuid
-import base64
 
 from leapp.exceptions import LeappError
 from leapp.utils.audit import create_audit_entry
@@ -167,14 +167,18 @@ def run(args, split=False, callback_raw=_console_logging_handler, callback_lineb
     :type stdin: int, str
     :return: {'stdout' : stdout, 'stderr': stderr, 'signal': signal, 'exit_code': exit_code, 'pid': pid}
     :rtype: dict
+    :raises: OSError if an executable is missing or has wrong permissions
+    :raises: CalledProcessError if the cmd has non-zero exit code and `checked` is False
+    :raises: TypeError if any input parameters have an invalid type
+    :raises: valueError if any of input parameters have an invalid value
     """
     if not args:
         message = 'Command to call is missing.'
         api.current_logger().error(message)
         raise ValueError(message)
     api.current_logger().debug('External command has started: {0}'.format(str(args)))
     _id = str(uuid.uuid4())
-    result = None
+    result = {}
     try:
         create_audit_entry('process-start', {'id': _id, 'parameters': args, 'env': env})
         result = _call(args, callback_raw=callback_raw, callback_linebuffered=callback_linebuffered,
@@ -191,6 +195,12 @@ def run(args, split=False, callback_raw=_console_logging_handler, callback_lineb
             result.update({
                 'stdout': result['stdout'].splitlines()
             })
+    except OSError:
+        # NOTE: currently we expect the result to be always set
+        # let's copy bash a little bit and set ecode 127
+        result = {'exit_code': '127', 'stdout': '', 'signal': 0, 'pid': 0}
+        result['stderr'] = 'File not found or permission denied: {}'.format(args[0])
+        raise
     finally:
         audit_result = result
         if not encoding:

leapp/libraries/stdlib/call.py

@@ -1,7 +1,10 @@
 from __future__ import print_function
 
+from distutils.spawn import find_executable
 import codecs
+import errno
 import os
+import sys
 
 from leapp.compat import string_types
 from leapp.libraries.stdlib.eventloop import POLL_HUP, POLL_IN, POLL_OUT, POLL_PRI, EventLoop
@@ -107,6 +110,10 @@ def _call(command, callback_raw=lambda fd, value: None, callback_linebuffered=la
         :type env: dict
         :return: {'stdout' : stdout, 'stderr': stderr, 'signal': signal, 'exit_code': exit_code, 'pid': pid}
         :rtype: dict
+        :raises: OSError if an executable is missing or has wrong permissions
+        :raises: CalledProcessError if the cmd has non-zero exit code and `checked` is False
+        :raises: TypeError if any input parameters have an invalid type
+        :raises: valueError if any of input parameters have an invalid value
     """
     if not isinstance(command, (list, tuple)):
         raise TypeError('command parameter has to be a list or tuple')
@@ -126,6 +133,17 @@ def _call(command, callback_raw=lambda fd, value: None, callback_linebuffered=la
         if not isinstance(env, dict):
             raise TypeError('env parameter has to be a dictionary')
         environ.update(env)
+
+    _path = (env or {}).get('PATH', None)
+    # NOTE(pstodulk): the find_executable function is from the distutils
+    # module which is deprecated and it is going to be removed in Python 3.12.
+    # In future, we should use the shutil.which function, however that one is
+    # not available for Python2. We are going to address the problem in future
+    # (e.g. when we drop support for Python 2).
+    # https://peps.python.org/pep-0632/
+    if not find_executable(command[0], _path):
+        raise OSError(errno.ENOENT, os.strerror(errno.ENOENT), command[0])
+
     # Create a separate pipe for stdout/stderr
     #
     # The parent process is going to use the read-end of the pipes for reading child's
@@ -214,4 +232,11 @@ def _call(command, callback_raw=lambda fd, value: None, callback_linebuffered=la
         os.close(stderr)
         os.dup2(wstdout, STDOUT)
         os.dup2(wstderr, STDERR)
-        os.execvpe(command[0], command, env=environ)
+        try:
+            os.execvpe(command[0], command, env=environ)
+        except OSError as e:
+            # This is a seatbelt in case the execvpe cannot be performed
+            # (e.g. permission denied) and we didn't catch this prior the fork.
+            # See the PR for more details: https://github.com/oamg/leapp/pull/836
+            sys.stderr.write('Error: Cannot execute {}: {}\n'.format(command[0], str(e)))
+            os._exit(1)

tests/scripts/test_stdlib_call_audit.py

@@ -1,8 +1,19 @@
+import os
 import pytest
 import six
 
 from leapp.libraries.stdlib import run
 
+CUR_DIR = os.path.dirname(os.path.abspath(__file__))
+
+
+@pytest.fixture
+def adjust_cwd():
+    previous_cwd = os.getcwd()
+    os.chdir(os.path.join(CUR_DIR, "../"))
+    yield
+    os.chdir(previous_cwd)
+
 
 def test_invalid_command():
     """
@@ -35,3 +46,24 @@ def test_no_encoding():
     cmd = ['echo', '-n', '-e', '\\xeb']
     result = run(cmd, encoding=None)
     assert isinstance(result['stdout'], six.binary_type)
+
+
+def test_missing_executable(monkeypatch, adjust_cwd):  # no-qa: W0613; pylint: disable=unused-argument
+    """
+    In case the executable is missing.
+
+    :return: Pass/Fail
+    """
+    def mocked_fork():
+        # raise the generic exception as we want to prevent fork in this case
+        # and want to bypass possible catch
+        raise Exception()  # no-qa: W0719; pylint: disable=broad-exception-raised
+
+    monkeypatch.setattr(os, 'fork', mocked_fork)
+    with pytest.raises(OSError):
+        run(['my-non-existing-exec-2023-asdf'])
+
+    with pytest.raises(OSError):
+        # this file is not executable, so even if it exists the OSError should
+        # be still raised
+        run(['panagrams'], env={'PATH': '../data/call_data/'})

tests/scripts/test_utils_project.py

@@ -5,13 +5,13 @@
 from helpers import TESTING_REPOSITORY_NAME
 from leapp.exceptions import CommandError
 from leapp.utils.repository import (
-    requires_repository,
-    to_snake_case,
-    make_class_name,
-    make_name,
     find_repository_basedir,
-    get_repository_name,
     get_repository_metadata,
+    get_repository_name,
+    make_class_name,
+    make_name,
+    requires_repository,
+    to_snake_case,
 )