issue7213: Open the pipes used by subprocesses with the FD_CLOEXEC flag from
the C code, using pipe2() when available. Adds unittests for close_fds and
cloexec behaviors.
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 62dfd36..729a53b 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -390,6 +390,23 @@
# POSIX defines PIPE_BUF as >= 512.
_PIPE_BUF = getattr(select, 'PIPE_BUF', 512)
+ if _posixsubprocess:
+ _create_pipe = _posixsubprocess.cloexec_pipe
+ else:
+ def _create_pipe():
+ try:
+ cloexec_flag = fcntl.FD_CLOEXEC
+ except AttributeError:
+ cloexec_flag = 1
+
+ fds = os.pipe()
+
+ old = fcntl.fcntl(fds[0], fcntl.F_GETFD)
+ fcntl.fcntl(fds[0], fcntl.F_SETFD, old | cloexec_flag)
+ old = fcntl.fcntl(fds[1], fcntl.F_GETFD)
+ fcntl.fcntl(fds[1], fcntl.F_SETFD, old | cloexec_flag)
+
+ return fds
__all__ = ["Popen", "PIPE", "STDOUT", "call", "check_call", "getstatusoutput",
"getoutput", "check_output", "CalledProcessError"]
@@ -1031,7 +1048,7 @@
if stdin is None:
pass
elif stdin == PIPE:
- p2cread, p2cwrite = os.pipe()
+ p2cread, p2cwrite = _create_pipe()
elif isinstance(stdin, int):
p2cread = stdin
else:
@@ -1041,7 +1058,7 @@
if stdout is None:
pass
elif stdout == PIPE:
- c2pread, c2pwrite = os.pipe()
+ c2pread, c2pwrite = _create_pipe()
elif isinstance(stdout, int):
c2pwrite = stdout
else:
@@ -1051,7 +1068,7 @@
if stderr is None:
pass
elif stderr == PIPE:
- errread, errwrite = os.pipe()
+ errread, errwrite = _create_pipe()
elif stderr == STDOUT:
errwrite = c2pwrite
elif isinstance(stderr, int):
@@ -1065,16 +1082,6 @@
errread, errwrite)
- def _set_cloexec_flag(self, fd):
- try:
- cloexec_flag = fcntl.FD_CLOEXEC
- except AttributeError:
- cloexec_flag = 1
-
- old = fcntl.fcntl(fd, fcntl.F_GETFD)
- fcntl.fcntl(fd, fcntl.F_SETFD, old | cloexec_flag)
-
-
def _close_fds(self, but):
os.closerange(3, but)
os.closerange(but + 1, MAXFD)
@@ -1116,10 +1123,9 @@
# For transferring possible exec failure from child to parent.
# Data format: "exception name:hex errno:description"
# Pickle is not used; it is complex and involves memory allocation.
- errpipe_read, errpipe_write = os.pipe()
+ errpipe_read, errpipe_write = _create_pipe()
try:
try:
- self._set_cloexec_flag(errpipe_write)
if _posixsubprocess:
# We must avoid complex work that could involve