Fixes Issue #14635: telnetlib will use poll() rather than select() when possible
to avoid failing due to the select() file descriptor limit.
Contributed by Akintayo Holder and under the Google contributor agreement.
diff --git a/Lib/telnetlib.py b/Lib/telnetlib.py
index bae4ae7..727e8f7 100644
--- a/Lib/telnetlib.py
+++ b/Lib/telnetlib.py
@@ -34,6 +34,7 @@
# Imported modules
+import errno
import sys
import socket
import select
@@ -205,6 +206,7 @@
self.sb = 0 # flag for SB and SE sequence.
self.sbdataq = ''
self.option_callback = None
+ self._has_poll = hasattr(select, 'poll')
if host is not None:
self.open(host, port, timeout)
@@ -287,6 +289,61 @@
is closed and no cooked data is available.
"""
+ if self._has_poll:
+ return self._read_until_with_poll(match, timeout)
+ else:
+ return self._read_until_with_select(match, timeout)
+
+ def _read_until_with_poll(self, match, timeout):
+ """Read until a given string is encountered or until timeout.
+
+ This method uses select.poll() to implement the timeout.
+ """
+ n = len(match)
+ call_timeout = timeout
+ if timeout is not None:
+ from time import time
+ time_start = time()
+ self.process_rawq()
+ i = self.cookedq.find(match)
+ if i < 0:
+ poller = select.poll()
+ poll_in_or_priority_flags = select.POLLIN | select.POLLPRI
+ poller.register(self, poll_in_or_priority_flags)
+ while i < 0 and not self.eof:
+ try:
+ ready = poller.poll(call_timeout)
+ except select.error as e:
+ if e.errno == errno.EINTR:
+ if timeout is not None:
+ elapsed = time() - time_start
+ call_timeout = timeout-elapsed
+ continue
+ raise
+ for fd, mode in ready:
+ if mode & poll_in_or_priority_flags:
+ i = max(0, len(self.cookedq)-n)
+ self.fill_rawq()
+ self.process_rawq()
+ i = self.cookedq.find(match, i)
+ if timeout is not None:
+ elapsed = time() - time_start
+ if elapsed >= timeout:
+ break
+ call_timeout = timeout-elapsed
+ poller.unregister(self)
+ if i >= 0:
+ i = i + n
+ buf = self.cookedq[:i]
+ self.cookedq = self.cookedq[i:]
+ return buf
+ return self.read_very_lazy()
+
+ def _read_until_with_select(self, match, timeout=None):
+ """Read until a given string is encountered or until timeout.
+
+ The timeout is implemented using select.select().
+ """
n = len(match)
self.process_rawq()
i = self.cookedq.find(match)
@@ -589,6 +646,79 @@
results are undeterministic, and may depend on the I/O timing.
"""
+ if self._has_poll:
+ return self._expect_with_poll(list, timeout)
+ else:
+ return self._expect_with_select(list, timeout)
+
+ def _expect_with_poll(self, expect_list, timeout=None):
+ """Read until one from a list of a regular expressions matches.
+
+ This method uses select.poll() to implement the timeout.
+ """
+ re = None
+ expect_list = expect_list[:]
+ indices = range(len(expect_list))
+ for i in indices:
+ if not hasattr(expect_list[i], "search"):
+ if not re: import re
+ expect_list[i] = re.compile(expect_list[i])
+ call_timeout = timeout
+ if timeout is not None:
+ from time import time
+ time_start = time()
+ self.process_rawq()
+ m = None
+ for i in indices:
+ m = expect_list[i].search(self.cookedq)
+ if m:
+ e = m.end()
+ text = self.cookedq[:e]
+ self.cookedq = self.cookedq[e:]
+ break
+ if not m:
+ poller = select.poll()
+ poll_in_or_priority_flags = select.POLLIN | select.POLLPRI
+ poller.register(self, poll_in_or_priority_flags)
+ while not m and not self.eof:
+ try:
+ ready = poller.poll(call_timeout)
+ except select.error as e:
+ if e.errno == errno.EINTR:
+ if timeout is not None:
+ elapsed = time() - time_start
+ call_timeout = timeout-elapsed
+ continue
+ raise
+ for fd, mode in ready:
+ if mode & poll_in_or_priority_flags:
+ self.fill_rawq()
+ self.process_rawq()
+ for i in indices:
+ m = expect_list[i].search(self.cookedq)
+ if m:
+ e = m.end()
+ text = self.cookedq[:e]
+ self.cookedq = self.cookedq[e:]
+ break
+ if timeout is not None:
+ elapsed = time() - time_start
+ if elapsed >= timeout:
+ break
+ call_timeout = timeout-elapsed
+ poller.unregister(self)
+ if m:
+ return (i, m, text)
+ text = self.read_very_lazy()
+ if not text and self.eof:
+ raise EOFError
+ return (-1, None, text)
+
+ def _expect_with_select(self, list, timeout=None):
+ """Read until one from a list of a regular expressions matches.
+
+ The timeout is implemented using select.select().
+ """
re = None
list = list[:]
indices = range(len(list))
diff --git a/Lib/test/test_telnetlib.py b/Lib/test/test_telnetlib.py
index 5a179f0..c66f49b 100644
--- a/Lib/test/test_telnetlib.py
+++ b/Lib/test/test_telnetlib.py
@@ -135,6 +135,28 @@
self.assertEqual(data, want[0])
self.assertEqual(telnet.read_all(), 'not seen')
+ def test_read_until_with_poll(self):
+ """Use select.poll() to implement telnet.read_until()."""
+ want = ['x' * 10, 'match', 'y' * 10, EOF_sigil]
+ self.dataq.put(want)
+ telnet = telnetlib.Telnet(HOST, self.port)
+ if not telnet._has_poll:
+ raise unittest.SkipTest('select.poll() is required')
+ telnet._has_poll = True
+ self.dataq.join()
+ data = telnet.read_until('match')
+ self.assertEqual(data, ''.join(want[:-2]))
+
+ def test_read_until_with_select(self):
+ """Use select.select() to implement telnet.read_until()."""
+ want = ['x' * 10, 'match', 'y' * 10, EOF_sigil]
+ self.dataq.put(want)
+ telnet = telnetlib.Telnet(HOST, self.port)
+ telnet._has_poll = False
+ self.dataq.join()
+ data = telnet.read_until('match')
+ self.assertEqual(data, ''.join(want[:-2]))
+
def test_read_all_A(self):
"""
read_all()
@@ -357,8 +379,75 @@
self.assertEqual('', telnet.read_sb_data())
nego.sb_getter = None # break the nego => telnet cycle
+
+class ExpectTests(TestCase):
+ def setUp(self):
+ self.evt = threading.Event()
+ self.dataq = Queue.Queue()
+ self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+ self.sock.settimeout(10)
+ self.port = test_support.bind_port(self.sock)
+ self.thread = threading.Thread(target=server, args=(self.evt,self.sock,
+ self.dataq))
+ self.thread.start()
+ self.evt.wait()
+
+ def tearDown(self):
+ self.thread.join()
+
+ # use a similar approach to testing timeouts as test_timeout.py
+ # these will never pass 100% but make the fuzz big enough that it is rare
+ block_long = 0.6
+ block_short = 0.3
+ def test_expect_A(self):
+ """
+ expect(expected, [timeout])
+ Read until the expected string has been seen, or a timeout is
+ hit (default is no timeout); may block.
+ """
+ want = ['x' * 10, 'match', 'y' * 10, EOF_sigil]
+ self.dataq.put(want)
+ telnet = telnetlib.Telnet(HOST, self.port)
+ self.dataq.join()
+ (_,_,data) = telnet.expect(['match'])
+ self.assertEqual(data, ''.join(want[:-2]))
+
+ def test_expect_B(self):
+ # test the timeout - it does NOT raise socket.timeout
+ want = ['hello', self.block_long, 'not seen', EOF_sigil]
+ self.dataq.put(want)
+ telnet = telnetlib.Telnet(HOST, self.port)
+ self.dataq.join()
+ (_,_,data) = telnet.expect(['not seen'], self.block_short)
+ self.assertEqual(data, want[0])
+ self.assertEqual(telnet.read_all(), 'not seen')
+
+ def test_expect_with_poll(self):
+ """Use select.poll() to implement telnet.expect()."""
+ want = ['x' * 10, 'match', 'y' * 10, EOF_sigil]
+ self.dataq.put(want)
+ telnet = telnetlib.Telnet(HOST, self.port)
+ if not telnet._has_poll:
+ raise unittest.SkipTest('select.poll() is required')
+ telnet._has_poll = True
+ self.dataq.join()
+ (_,_,data) = telnet.expect(['match'])
+ self.assertEqual(data, ''.join(want[:-2]))
+
+ def test_expect_with_select(self):
+ """Use select.select() to implement telnet.expect()."""
+ want = ['x' * 10, 'match', 'y' * 10, EOF_sigil]
+ self.dataq.put(want)
+ telnet = telnetlib.Telnet(HOST, self.port)
+ telnet._has_poll = False
+ self.dataq.join()
+ (_,_,data) = telnet.expect(['match'])
+ self.assertEqual(data, ''.join(want[:-2]))
+
+
def test_main(verbose=None):
- test_support.run_unittest(GeneralTests, ReadTests, OptionTests)
+ test_support.run_unittest(GeneralTests, ReadTests, OptionTests,
+ ExpectTests)
if __name__ == '__main__':
test_main()
diff --git a/Misc/ACKS b/Misc/ACKS
index 548279a..471e6a9 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -369,6 +369,7 @@
Albert Hofkamp
Tomas Hoger
Jonathan Hogg
+Akintayo Holder
Gerrit Holl
Shane Holloway
Rune Holm
diff --git a/Misc/NEWS b/Misc/NEWS
index 52439fe..4b05aa3 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -84,6 +84,9 @@
Library
-------
+- Issue #14635: telnetlib will use poll() rather than select() when possible
+ to avoid failing due to the select() file descriptor limit.
+
- Issue #15247: FileIO now raises an error when given a file descriptor
pointing to a directory.