/offlineimap/head: changeset 474

- offlineimap (3.99.17) unstable; urgency=low

- Fixed two potential obscure race conditions in folder/Maildir.py. +
  Condition 1 involved the gettimeseq() function. This function
  accesses per-module variables but does not have a lock. It may have
  been possible for this to have been called in such a way that
  timeseq was not properly updated. + Condition 2 involved the call to
  gettimeseq(). Since the timeseq is based on the system clock, we now
  use the time as reported inside timeseq() rather than outside. This
  way, we can be assured that the same value is in use both places.

- Added debug code to savemessage in folder/Maildir.py to try to track
  down a mysterious 0-length file bug. -- John Goerzen
  <jgoerzen@complete.org> Tue, 6 May 2003 09:21:38 -0500

offlineimap/head/debian/changelog

@@ -1,3 +1,19 @@
+offlineimap (3.99.17) unstable; urgency=low
+
+  * Fixed two potential obscure race conditions in folder/Maildir.py.
+    + Condition 1 involved the gettimeseq() function.  This function
+      accesses per-module variables but does not have a lock.  It may have
+      been possible for this to have been called in such a way that timeseq
+      was not properly updated.
+    + Condition 2 involved the call to gettimeseq().  Since the timeseq is
+      based on the system clock, we now use the time as reported inside
+      timeseq() rather than outside.  This way, we can be assured that the
+      same value is in use both places.
+  * Added debug code to savemessage in folder/Maildir.py to try to track
+    down a mysterious 0-length file bug.
+
+ -- John Goerzen <jgoerzen@complete.org>  Tue,  6 May 2003 07:25:38 -0500
+
 offlineimap (3.99.16) unstable; urgency=low
 
   * This is a 4.0 TRACK release, and may be unstable or in flux!

offlineimap/head/offlineimap/folder/Maildir.py

@@ -18,6 +18,8 @@
 
 from Base import BaseFolder
 from offlineimap import imaputil
+from offlineimap.ui import UIBase
+from threading import Lock
 import os.path, os, re, time, socket, md5
 
 foldermatchre = re.compile(',FMD5=([0-9a-f]{32})')
@@ -26,17 +28,22 @@ flagmatchre = re.compile(':.*2,([A-Z]+)')
 
 timeseq = 0
 lasttime = long(0)
+timelock = Lock()
 
 def gettimeseq():
-    global lasttime, timeseq
+    global lasttime, timeseq, timelock
-    thistime = long(time.time())
+    timelock.acquire()
-    if thistime == lasttime:
+    try:
-        timeseq += 1
+        thistime = long(time.time())
-        return timeseq
+        if thistime == lasttime:
-    else:
+            timeseq += 1
-        lasttime = long(time.time())
+            return (thistime, timeseq)
-        timeseq = 0
+        else:
-        return timeseq
+            lasttime = thistime
+            timeseq = 0
+            return (thistime, timeseq)
+    finally:
+        timelock.release()
 
 class MaildirFolder(BaseFolder):
     def __init__(self, root, name, sep, repository, accountname):
@@ -118,6 +125,9 @@ class MaildirFolder(BaseFolder):
         return retval.replace("\r\n", "\n")
 
     def savemessage(self, uid, content, flags):
+        ui = UIBase.getglobalui()
+        ui.debug('maildir', 'savemessage: called to write with flags %s and content %s' % \
+                 (repr(flags), repr(content)))
         if uid < 0:
             # We cannot assign a new uid.
             return uid
@@ -137,9 +147,10 @@ class MaildirFolder(BaseFolder):
         while 1:
             if attempts > 15:
                 raise IOError, "Couldn't write to file %s" % messagename
+            timeval, timeseq = gettimeseq()
             messagename = '%d_%d.%d.%s,U=%d,FMD5=%s' % \
-                          (long(time.time()),
+                          (timeval,
-                           gettimeseq(),
+                           timeseq,
                            os.getpid(),
                            socket.gethostname(),
                            uid,
@@ -150,15 +161,19 @@ class MaildirFolder(BaseFolder):
             else:
                 break
         tmpmessagename = messagename.split(',')[0]
+        ui.debug('maildir', 'savemessage: using temporary name %s' % tmpmessagename)
         file = open(os.path.join(tmpdir, tmpmessagename), "wt")
         file.write(content)
         file.close()
+        ui.debug('maildir', 'savemessage: moving from %s to %s' % \
+                 (tmpmessagename, messagename))
         os.link(os.path.join(tmpdir, tmpmessagename),
                 os.path.join(newdir, messagename))
         os.unlink(os.path.join(tmpdir, tmpmessagename))
         self.messagelist[uid] = {'uid': uid, 'flags': [],
                                  'filename': os.path.join(newdir, messagename)}
         self.savemessageflags(uid, flags)
+        ui.debug('maildir', 'savemessage: returning uid %d' % uid)
         return uid
         
     def getmessageflags(self, uid):