mirror of https://github.com/python/cpython
Merged revisions 83944 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k ........ r83944 | antoine.pitrou | 2010-08-11 15:31:33 +0200 (mer., 11 août 2010) | 6 lines Issue #9550: a BufferedReader could issue an additional read when the original read request had been satisfied, which can block indefinitely when the underlying raw IO channel is e.g. a socket. Report and original patch by Jason V. Miller. ........
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@ -57,12 +57,14 @@ class MockRawIO:
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self._read_stack = list(read_stack)
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self._read_stack = list(read_stack)
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self._write_stack = []
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self._write_stack = []
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self._reads = 0
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self._reads = 0
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self._extraneous_reads = 0
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def read(self, n=None):
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def read(self, n=None):
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self._reads += 1
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self._reads += 1
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try:
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try:
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return self._read_stack.pop(0)
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return self._read_stack.pop(0)
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except:
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except:
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self._extraneous_reads += 1
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return b""
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return b""
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def write(self, b):
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def write(self, b):
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@ -93,6 +95,7 @@ class MockRawIO:
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try:
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try:
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data = self._read_stack[0]
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data = self._read_stack[0]
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except IndexError:
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except IndexError:
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self._extraneous_reads += 1
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return 0
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return 0
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if data is None:
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if data is None:
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del self._read_stack[0]
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del self._read_stack[0]
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@ -831,6 +834,27 @@ class BufferedReaderTest(unittest.TestCase, CommonBufferedTests):
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self.assertRaises(IOError, bufio.seek, 0)
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self.assertRaises(IOError, bufio.seek, 0)
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self.assertRaises(IOError, bufio.tell)
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self.assertRaises(IOError, bufio.tell)
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def test_no_extraneous_read(self):
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# Issue #9550; when the raw IO object has satisfied the read request,
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# we should not issue any additional reads, otherwise it may block
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# (e.g. socket).
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bufsize = 16
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for n in (2, bufsize - 1, bufsize, bufsize + 1, bufsize * 2):
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rawio = self.MockRawIO([b"x" * n])
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bufio = self.tp(rawio, bufsize)
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self.assertEqual(bufio.read(n), b"x" * n)
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# Simple case: one raw read is enough to satisfy the request.
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self.assertEqual(rawio._extraneous_reads, 0,
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"failed for {}: {} != 0".format(n, rawio._extraneous_reads))
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# A more complex case where two raw reads are needed to satisfy
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# the request.
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rawio = self.MockRawIO([b"x" * (n - 1), b"x"])
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bufio = self.tp(rawio, bufsize)
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self.assertEqual(bufio.read(n), b"x" * n)
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self.assertEqual(rawio._extraneous_reads, 0,
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"failed for {}: {} != 0".format(n, rawio._extraneous_reads))
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class CBufferedReaderTest(BufferedReaderTest):
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class CBufferedReaderTest(BufferedReaderTest):
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tp = io.BufferedReader
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tp = io.BufferedReader
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@ -528,6 +528,7 @@ Trent Mick
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Aristotelis Mikropoulos
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Aristotelis Mikropoulos
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Damien Miller
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Damien Miller
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Chad Miller
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Chad Miller
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Jason V. Miller
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Jay T. Miller
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Jay T. Miller
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Roman Milner
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Roman Milner
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Andrii V. Mishkovskyi
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Andrii V. Mishkovskyi
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@ -29,6 +29,11 @@ Core and Builtins
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Library
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Library
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-------
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-------
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- Issue #9550: a BufferedReader could issue an additional read when the
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original read request had been satisfied, which could block indefinitely
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when the underlying raw IO channel was e.g. a socket. Report and original
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patch by Jason V. Miller.
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- Issue #9551: Don't raise TypeError when setting the value to None for
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- Issue #9551: Don't raise TypeError when setting the value to None for
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SafeConfigParser instances constructed with allow_no_value == True.
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SafeConfigParser instances constructed with allow_no_value == True.
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@ -1388,7 +1388,10 @@ _bufferedreader_read_generic(buffered *self, Py_ssize_t n)
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self->pos = 0;
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self->pos = 0;
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self->raw_pos = 0;
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self->raw_pos = 0;
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self->read_end = 0;
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self->read_end = 0;
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while (self->read_end < self->buffer_size) {
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/* NOTE: when the read is satisfied, we avoid issuing any additional
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reads, which could block indefinitely (e.g. on a socket).
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See issue #9550. */
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while (remaining > 0 && self->read_end < self->buffer_size) {
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Py_ssize_t r = _bufferedreader_fill_buffer(self);
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Py_ssize_t r = _bufferedreader_fill_buffer(self);
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if (r == -1)
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if (r == -1)
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goto error;
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goto error;
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