_setup_pipes: copy descriptor flags after dup2

diff --git a/pym/portage/process.py b/pym/portage/process.py
index 3ec6d70cf9a0c18a56b12a2d6bb2f22cf62ef3e6..2a2fcac7713e3f95a64dcf630c341b78ba21c7a1 100644 (file)
--- a/pym/portage/process.py
+++ b/pym/portage/process.py
@@ -35,6 +35,17 @@ except ImportError:
 if sys.hexversion >= 0x3000000:
        basestring = str
 
+# Support PEP 446 for Python >=3.4
+try:
+       _set_inheritable = _os.set_inheritable
+except AttributeError:
+       _set_inheritable = None
+
+try:
+       _FD_CLOEXEC = fcntl.FD_CLOEXEC
+except AttributeError:
+       _FD_CLOEXEC = None
+
 # Prefer /proc/self/fd if available (/dev/fd
 # doesn't work on solaris, see bug #474536).
 for _fd_dir in ("/proc/self/fd", "/dev/fd"):
@@ -539,12 +550,6 @@ def _setup_pipes(fd_pipes, close_fds=True, inheritable=None):
        interference.
        """
 
-       # Support PEP 446 for Python >=3.4
-       try:
-               set_inheritable = _os.set_inheritable
-       except AttributeError:
-               set_inheritable = None
-
        reverse_map = {}
        # To protect from cases where direct assignment could
        # clobber needed fds ({1:2, 2:1}) we create a reverse map
@@ -564,6 +569,7 @@ def _setup_pipes(fd_pipes, close_fds=True, inheritable=None):
        while reverse_map:
 
                oldfd, newfds = reverse_map.popitem()
+               old_fdflags = None
 
                for newfd in newfds:
                        if newfd in reverse_map:
@@ -574,14 +580,26 @@ def _setup_pipes(fd_pipes, close_fds=True, inheritable=None):
                                # unused file discriptors).
                                backup_fd = os.dup(newfd)
                                reverse_map[backup_fd] = reverse_map.pop(newfd)
+
                        if oldfd != newfd:
                                os.dup2(oldfd, newfd)
+                               if old_fdflags is None:
+                                       old_fdflags = fcntl.fcntl(oldfd, fcntl.F_GETFD)
+                               fcntl.fcntl(newfd, fcntl.F_SETFD, old_fdflags)
+
+                       if _set_inheritable is not None:
+
+                               inheritable_state = None
+                               if not (old_fdflags is None or _FD_CLOEXEC is None):
+                                       inheritable_state = not bool(old_fdflags & _FD_CLOEXEC)
 
-                       if set_inheritable is not None:
                                if inheritable is not None:
-                                       set_inheritable(newfd, inheritable)
+                                       if inheritable_state is not inheritable:
+                                               _set_inheritable(newfd, inheritable)
+
                                elif newfd in (0, 1, 2):
-                                       set_inheritable(newfd, True)
+                                       if inheritable_state is not True:
+                                               _set_inheritable(newfd, True)
 
                if oldfd not in fd_pipes:
                        # If oldfd is not a key in fd_pipes, then it's safe