[Python-checkins] r73825 - in python/trunk/Lib: subprocess.py test/test_subprocess.py
gregory.p.smith
python-checkins at python.org
Sat Jul 4 03:49:29 CEST 2009
Author: gregory.p.smith
Date: Sat Jul 4 03:49:29 2009
New Revision: 73825
Log:
Use select.poll() in subprocess, when available, rather than select() so that
it does not fail when file descriptors are large. Fixes issue3392.
Patch largely contributed by Frank Chu (fpmc) with some improvements by me.
See http://bugs.python.org/issue3392.
Candidate for backporting to release26-maint as it is a bug fix and changes no
public API.
Modified:
python/trunk/Lib/subprocess.py
python/trunk/Lib/test/test_subprocess.py
Modified: python/trunk/Lib/subprocess.py
==============================================================================
--- python/trunk/Lib/subprocess.py (original)
+++ python/trunk/Lib/subprocess.py Sat Jul 4 03:49:29 2009
@@ -413,6 +413,7 @@
error = IOError
else:
import select
+ _has_poll = hasattr(select, 'poll')
import errno
import fcntl
import pickle
@@ -425,12 +426,10 @@
except:
MAXFD = 256
-# True/False does not exist on 2.2.0
-#try:
-# False
-#except NameError:
-# False = 0
-# True = 1
+# When select or poll has indicated that the file is writable,
+# we can write up to _PIPE_BUF bytes without risk of blocking.
+# POSIX defines PIPE_BUF as >= 512.
+_PIPE_BUF = getattr(select, 'PIPE_BUF', 512)
_active = []
@@ -1191,19 +1190,100 @@
def _communicate(self, input):
- read_set = []
- write_set = []
- stdout = None # Return
- stderr = None # Return
-
if self.stdin:
# Flush stdio buffer. This might block, if the user has
# been writing to .stdin in an uncontrolled fashion.
self.stdin.flush()
- if input:
- write_set.append(self.stdin)
- else:
+ if not input:
self.stdin.close()
+
+ if _has_poll:
+ stdout, stderr = self._communicate_with_poll(input)
+ else:
+ stdout, stderr = self._communicate_with_select(input)
+
+ # All data exchanged. Translate lists into strings.
+ if stdout is not None:
+ stdout = ''.join(stdout)
+ if stderr is not None:
+ stderr = ''.join(stderr)
+
+ # Translate newlines, if requested. We cannot let the file
+ # object do the translation: It is based on stdio, which is
+ # impossible to combine with select (unless forcing no
+ # buffering).
+ if self.universal_newlines and hasattr(file, 'newlines'):
+ if stdout:
+ stdout = self._translate_newlines(stdout)
+ if stderr:
+ stderr = self._translate_newlines(stderr)
+
+ self.wait()
+ return (stdout, stderr)
+
+
+ def _communicate_with_poll(self, input):
+ stdout = None # Return
+ stderr = None # Return
+ fd2file = {}
+ fd2output = {}
+
+ poller = select.poll()
+ def register_and_append(file_obj, eventmask):
+ poller.register(file_obj.fileno(), eventmask)
+ fd2file[file_obj.fileno()] = file_obj
+
+ def close_unregister_and_remove(fd):
+ poller.unregister(fd)
+ fd2file[fd].close()
+ fd2file.pop(fd)
+
+ if self.stdin and input:
+ register_and_append(self.stdin, select.POLLOUT)
+
+ select_POLLIN_POLLPRI = select.POLLIN | select.POLLPRI
+ if self.stdout:
+ register_and_append(self.stdout, select_POLLIN_POLLPRI)
+ fd2output[self.stdout.fileno()] = stdout = []
+ if self.stderr:
+ register_and_append(self.stderr, select_POLLIN_POLLPRI)
+ fd2output[self.stderr.fileno()] = stderr = []
+
+ input_offset = 0
+ while fd2file:
+ try:
+ ready = poller.poll()
+ except select.error, e:
+ if e.args[0] == errno.EINTR:
+ continue
+ raise
+
+ for fd, mode in ready:
+ if mode & select.POLLOUT:
+ chunk = input[input_offset : input_offset + _PIPE_BUF]
+ input_offset += os.write(fd, chunk)
+ if input_offset >= len(input):
+ close_unregister_and_remove(fd)
+ elif mode & select_POLLIN_POLLPRI:
+ data = os.read(fd, 4096)
+ if not data:
+ close_unregister_and_remove(fd)
+ fd2output[fd].append(data)
+ else:
+ # Ignore hang up or errors.
+ close_unregister_and_remove(fd)
+
+ return (stdout, stderr)
+
+
+ def _communicate_with_select(self, input):
+ read_set = []
+ write_set = []
+ stdout = None # Return
+ stderr = None # Return
+
+ if self.stdin and input:
+ write_set.append(self.stdin)
if self.stdout:
read_set.append(self.stdout)
stdout = []
@@ -1221,10 +1301,7 @@
raise
if self.stdin in wlist:
- # When select has indicated that the file is writable,
- # we can write up to PIPE_BUF bytes without risk
- # blocking. POSIX defines PIPE_BUF >= 512
- chunk = input[input_offset : input_offset + 512]
+ chunk = input[input_offset : input_offset + _PIPE_BUF]
bytes_written = os.write(self.stdin.fileno(), chunk)
input_offset += bytes_written
if input_offset >= len(input):
@@ -1245,25 +1322,9 @@
read_set.remove(self.stderr)
stderr.append(data)
- # All data exchanged. Translate lists into strings.
- if stdout is not None:
- stdout = ''.join(stdout)
- if stderr is not None:
- stderr = ''.join(stderr)
-
- # Translate newlines, if requested. We cannot let the file
- # object do the translation: It is based on stdio, which is
- # impossible to combine with select (unless forcing no
- # buffering).
- if self.universal_newlines and hasattr(file, 'newlines'):
- if stdout:
- stdout = self._translate_newlines(stdout)
- if stderr:
- stderr = self._translate_newlines(stderr)
-
- self.wait()
return (stdout, stderr)
+
def send_signal(self, sig):
"""Send a signal to the process
"""
Modified: python/trunk/Lib/test/test_subprocess.py
==============================================================================
--- python/trunk/Lib/test/test_subprocess.py (original)
+++ python/trunk/Lib/test/test_subprocess.py Sat Jul 4 03:49:29 2009
@@ -766,8 +766,24 @@
p.terminate()
self.assertNotEqual(p.wait(), 0)
+
+unit_tests = [ProcessTestCase]
+
+if subprocess._has_poll:
+ class ProcessTestCaseNoPoll(ProcessTestCase):
+ def setUp(self):
+ subprocess._has_poll = False
+ ProcessTestCase.setUp(self)
+
+ def tearDown(self):
+ subprocess._has_poll = True
+ ProcessTestCase.tearDown(self)
+
+ unit_tests.append(ProcessTestCaseNoPoll)
+
+
def test_main():
- test_support.run_unittest(ProcessTestCase)
+ test_support.run_unittest(*unit_tests)
if hasattr(test_support, "reap_children"):
test_support.reap_children()
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