Issue #10806, issue #9905: Fix subprocess pipes when some of the standard
file descriptors (0, 1, 2) are closed in the parent process. Initial
patch by Ross Lagerwall.
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index c12898d..7d3f77f 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -393,22 +393,22 @@
# POSIX defines PIPE_BUF as >= 512.
_PIPE_BUF = getattr(select, 'PIPE_BUF', 512)
+ _FD_CLOEXEC = getattr(fcntl, 'FD_CLOEXEC', 1)
+
+ def _set_cloexec(fd, cloexec):
+ old = fcntl.fcntl(fd, fcntl.F_GETFD)
+ if cloexec:
+ fcntl.fcntl(fd, fcntl.F_SETFD, old | _FD_CLOEXEC)
+ else:
+ fcntl.fcntl(fd, fcntl.F_SETFD, old & ~_FD_CLOEXEC)
+
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)
-
+ _set_cloexec(fds[0], True)
+ _set_cloexec(fds[1], True)
return fds
__all__ = ["Popen", "PIPE", "STDOUT", "call", "check_call", "getstatusoutput",
@@ -1194,23 +1194,25 @@
os.close(errpipe_read)
# Dup fds for child
- if p2cread != -1:
- os.dup2(p2cread, 0)
- if c2pwrite != -1:
- os.dup2(c2pwrite, 1)
- if errwrite != -1:
- os.dup2(errwrite, 2)
+ def _dup2(a, b):
+ # dup2() removes the CLOEXEC flag but
+ # we must do it ourselves if dup2()
+ # would be a no-op (issue #10806).
+ if a == b:
+ _set_cloexec(a, False)
+ elif a != -1:
+ os.dup2(a, b)
+ _dup2(p2cread, 0)
+ _dup2(c2pwrite, 1)
+ _dup2(errwrite, 2)
# Close pipe fds. Make sure we don't close the
# same fd more than once, or standard fds.
- if p2cread != -1 and p2cread not in (0,):
- os.close(p2cread)
- if (c2pwrite != -1 and
- c2pwrite not in (p2cread, 1)):
- os.close(c2pwrite)
- if (errwrite != -1 and
- errwrite not in (p2cread, c2pwrite, 2)):
- os.close(errwrite)
+ closed = set()
+ for fd in [p2cread, c2pwrite, errwrite]:
+ if fd > 2 and fd not in closed:
+ os.close(fd)
+ closed.add(fd)
# Close all other fds, if asked for
if close_fds: