From 1fab6d9c25f0254f1bf4376fc76da05378703e46 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Mon, 2 Apr 2018 08:59:36 +0100
Subject: [PATCH] ansible: permit execve() of temporary files on Linux.

---
 ansible_mitogen/runner.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/ansible_mitogen/runner.py b/ansible_mitogen/runner.py
index f5cb1283..c9ab8427 100644
--- a/ansible_mitogen/runner.py
+++ b/ansible_mitogen/runner.py
@@ -59,6 +59,19 @@ ansible.module_utils.basic._ANSIBLE_ARGS = '{}'
 LOG = logging.getLogger(__name__)
 
 
+def reopen_readonly(fp):
+    """
+    Replace the file descriptor belonging to the file object `fp` with one
+    open on the same file (`fp.name`), but opened with :py:data:`os.O_RDONLY`.
+    This enables temporary files to be executed on Linux, which usually theows
+    ``ETXTBUSY`` if any writeable handle exists pointing to a file passed to
+    `execve()`.
+    """
+    fd = os.open(fp.name, os.O_RDONLY)
+    os.dup2(fd, fp.fileno())
+    os.close(fd)
+
+
 class Runner(object):
     """
     Ansible module runner. After instantiation (with kwargs supplied by the
@@ -189,6 +202,7 @@ class ProgramRunner(Runner):
         self.program_fp.write(self._get_program())
         self.program_fp.flush()
         os.chmod(self.program_fp.name, int('0700', 8))
+        reopen_readonly(self.program_fp)
 
     def _get_program(self):
         """
@@ -244,6 +258,7 @@ class ArgsFileRunner(Runner):
         )
         self.args_fp.write(self._get_args_contents())
         self.args_fp.flush()
+        reopen_readonly(self.program_fp)
 
     def _get_args_contents(self):
         """