From 1eda9e7c3074bfe37674c8140b3d02bf94caf4f3 Mon Sep 17 00:00:00 2001 From: "Gregory P. Smith" Date: Sat, 30 Nov 2013 19:02:57 -0800 Subject: Fixes Issue #15798 - subprocess.Popen() no longer fails if file descriptor 0, 1 or 2 is closed. --- Lib/subprocess.py | 5 ++++- Lib/test/test_subprocess.py | 21 +++++++++++++++++++++ Misc/NEWS | 3 +++ Modules/_posixsubprocess.c | 6 +----- 4 files changed, 29 insertions(+), 6 deletions(-) diff --git a/Lib/subprocess.py b/Lib/subprocess.py index c3a2788..a659087 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -1368,7 +1368,10 @@ class Popen(object): executable_list = tuple( os.path.join(os.fsencode(dir), executable) for dir in os.get_exec_path(env)) - fds_to_keep = set(pass_fds) + # Never close stdin, stdout and stderr for the child. + fds_to_keep = {0,1,2} + fds_to_keep.update(pass_fds) + # Our child uses this one to signal error before exec(). fds_to_keep.add(errpipe_write) self.pid = _posixsubprocess.fork_exec( args, executable_list, diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py index 77f1ba3..f5a70a3 100644 --- a/Lib/test/test_subprocess.py +++ b/Lib/test/test_subprocess.py @@ -1559,6 +1559,27 @@ class POSIXProcessTestCase(BaseTestCase): # all standard fds closed. self.check_close_std_fds([0, 1, 2]) + def test_small_errpipe_write_fd(self): + """Issue #15798: Popen should work when stdio fds are available.""" + new_stdin = os.dup(0) + new_stdout = os.dup(1) + try: + os.close(0) + os.close(1) + + # Side test: if errpipe_write fails to have its CLOEXEC + # flag set this should cause the parent to think the exec + # failed. Extremely unlikely: everyone supports CLOEXEC. + subprocess.Popen([ + sys.executable, "-c", + "print('AssertionError:0:CLOEXEC failure.')"]).wait() + finally: + # Restore original stdin and stdout + os.dup2(new_stdin, 0) + os.dup2(new_stdout, 1) + os.close(new_stdin) + os.close(new_stdout) + def test_remapping_std_fds(self): # open up some temporary files temps = [mkstemp() for i in range(3)] diff --git a/Misc/NEWS b/Misc/NEWS index 0acbafd..4742b9b 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -18,6 +18,9 @@ Core and Builtins Library ------- +- Issue #15798: Fixed subprocess.Popen() to no longer fail if file + descriptor 0, 1 or 2 is closed. + - Issue #19088: Fixed incorrect caching of the copyreg module in object.__reduce__() and object.__reduce_ex__(). diff --git a/Modules/_posixsubprocess.c b/Modules/_posixsubprocess.c index 8d65530..fa1975c 100644 --- a/Modules/_posixsubprocess.c +++ b/Modules/_posixsubprocess.c @@ -449,7 +449,7 @@ child_exec(char *const exec_array[], local_max_fd = max_fd; #endif /* TODO HP-UX could use pstat_getproc() if anyone cares about it. */ - _close_open_fd_range(3, local_max_fd, py_fds_to_keep); + _close_open_fd_range(0, local_max_fd, py_fds_to_keep); } /* This loop matches the Lib/os.py _execvpe()'s PATH search when */ @@ -526,10 +526,6 @@ subprocess_fork_exec(PyObject* self, PyObject *args) &restore_signals, &call_setsid, &preexec_fn)) return NULL; - if (close_fds && errpipe_write < 3) { /* precondition */ - PyErr_SetString(PyExc_ValueError, "errpipe_write must be >= 3"); - return NULL; - } if (PySequence_Length(py_fds_to_keep) < 0) { PyErr_SetString(PyExc_ValueError, "cannot get length of fds_to_keep"); return NULL; -- cgit v0.12