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author | Vinay Sajip <vinay_sajip@yahoo.co.uk> | 2012-04-24 22:33:33 (GMT) |
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committer | Vinay Sajip <vinay_sajip@yahoo.co.uk> | 2012-04-24 22:33:33 (GMT) |
commit | a5798ded26e3ad67946b7d8150a8e13b0075fbf8 (patch) | |
tree | 508e1844c0372f19b7bcdbf22d9aeb7de1635ca6 /Lib/logging | |
parent | 5438ed1572f5e379cac8b85ed2226101a1bfcacc (diff) | |
parent | 66b8b08752a2e30cbbbd12295247df050d534c4b (diff) | |
download | cpython-a5798ded26e3ad67946b7d8150a8e13b0075fbf8.zip cpython-a5798ded26e3ad67946b7d8150a8e13b0075fbf8.tar.gz cpython-a5798ded26e3ad67946b7d8150a8e13b0075fbf8.tar.bz2 |
Issue #14632: Updated WatchedFileHandler to deal with race condition. Thanks to John Mulligan for the problem report and patch.
Diffstat (limited to 'Lib/logging')
-rw-r--r-- | Lib/logging/handlers.py | 49 |
1 files changed, 30 insertions, 19 deletions
diff --git a/Lib/logging/handlers.py b/Lib/logging/handlers.py index 9c63797..7a97c80 100644 --- a/Lib/logging/handlers.py +++ b/Lib/logging/handlers.py @@ -23,7 +23,7 @@ Copyright (C) 2001-2012 Vinay Sajip. All Rights Reserved. To use, simply 'import logging.handlers' and log away! """ -import logging, socket, os, pickle, struct, time, re +import errno, logging, socket, os, pickle, struct, time, re from codecs import BOM_UTF8 from stat import ST_DEV, ST_INO, ST_MTIME import queue @@ -419,11 +419,13 @@ class WatchedFileHandler(logging.FileHandler): """ def __init__(self, filename, mode='a', encoding=None, delay=False): logging.FileHandler.__init__(self, filename, mode, encoding, delay) - if not os.path.exists(self.baseFilename): - self.dev, self.ino = -1, -1 - else: - stat = os.stat(self.baseFilename) - self.dev, self.ino = stat[ST_DEV], stat[ST_INO] + self.dev, self.ino = -1, -1 + self._statstream() + + def _statstream(self): + if self.stream: + sres = os.fstat(self.stream.fileno()) + self.dev, self.ino = sres[ST_DEV], sres[ST_INO] def emit(self, record): """ @@ -433,21 +435,30 @@ class WatchedFileHandler(logging.FileHandler): has, close the old stream and reopen the file to get the current stream. """ - if not os.path.exists(self.baseFilename): - stat = None - changed = True - else: - stat = os.stat(self.baseFilename) - changed = (stat[ST_DEV] != self.dev) or (stat[ST_INO] != self.ino) - if changed and self.stream is not None: - self.stream.flush() - self.stream.close() - self.stream = self._open() - if stat is None: - stat = os.stat(self.baseFilename) - self.dev, self.ino = stat[ST_DEV], stat[ST_INO] + # Reduce the chance of race conditions by stat'ing by path only + # once and then fstat'ing our new fd if we opened a new log stream. + # See issue #14632: Thanks to John Mulligan for the problem report + # and patch. + try: + # stat the file by path, checking for existence + sres = os.stat(self.baseFilename) + except OSError as err: + if err.errno == errno.ENOENT: + sres = None + else: + raise + # compare file system stat with that of our stream file handle + if not sres or sres[ST_DEV] != self.dev or sres[ST_INO] != self.ino: + if self.stream is not None: + # we have an open file handle, clean it up + self.stream.flush() + self.stream.close() + # open a new file handle and get new stat info from that fd + self.stream = self._open() + self._statstream() logging.FileHandler.emit(self, record) + class SocketHandler(logging.Handler): """ A handler class which writes logging records, in pickle format, to |