[Python-checkins] cpython (2.7): #19037: adjust file times before moving maildir files into place.

Wed Sep 18 14:39:34 CEST 2013

http://hg.python.org/cpython/rev/041caa64486b
changeset: 85747:041caa64486b
branch: 2.7
parent: 85736:48be42b94381
user: R David Murray <rdmurray at bitdance.com>
date: Wed Sep 18 08:35:45 2013 -0400
summary:
 #19037: adjust file times *before* moving maildir files into place.
This avoids race conditions when other programs are monitoring
the maildir directory. Patch by janzert.
files:
 Lib/mailbox.py | 18 +++++++++++++-----
 Misc/NEWS | 4 ++++
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/Lib/mailbox.py b/Lib/mailbox.py
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -286,6 +286,12 @@
 suffix = ''
 uniq = os.path.basename(tmp_file.name).split(self.colon)[0]
 dest = os.path.join(self._path, subdir, uniq + suffix)
+ if isinstance(message, MaildirMessage):
+ os.utime(tmp_file.name,
+ (os.path.getatime(tmp_file.name), message.get_date()))
+ # No file modification should be done after the file is moved to its
+ # final position in order to prevent race conditions with changes
+ # from other programs
 try:
 if hasattr(os, 'link'):
 os.link(tmp_file.name, dest)
@@ -299,8 +305,6 @@
 % dest)
 else:
 raise
- if isinstance(message, MaildirMessage):
- os.utime(dest, (os.path.getatime(dest), message.get_date()))
 return uniq
 
 def remove(self, key):
@@ -335,11 +339,15 @@
 else:
 suffix = ''
 self.discard(key)
+ tmp_path = os.path.join(self._path, temp_subpath)
 new_path = os.path.join(self._path, subdir, key + suffix)
- os.rename(os.path.join(self._path, temp_subpath), new_path)
 if isinstance(message, MaildirMessage):
- os.utime(new_path, (os.path.getatime(new_path),
- message.get_date()))
+ os.utime(tmp_path,
+ (os.path.getatime(tmp_path), message.get_date()))
+ # No file modification should be done after the file is moved to its
+ # final position in order to prevent race conditions with changes
+ # from other programs
+ os.rename(tmp_path, new_path)
 
 def get_message(self, key):
 """Return a Message representation or raise a KeyError."""
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -32,6 +32,10 @@
 Library
 -------
 
+- Issue #19037: The mailbox module now makes all changes to maildir files
+ before moving them into place, to avoid race conditions with other programs
+ that may be accessing the maildir directory.
+
 - Issue #14984: On POSIX systems, when netrc is called without a filename
 argument (and therefore is reading the user's $HOME/.netrc file), it now
 enforces the same security rules as typical ftp clients: the .netrc file must
-- 
Repository URL: http://hg.python.org/cpython


[Python-checkins] cpython (2.7): #19037: adjust file times *before* moving maildir files into place.

[Python-checkins] cpython (2.7): #19037: adjust file times before moving maildir files into place.