Commit 884a0e26 authored by Nick Mathewson's avatar Nick Mathewson 🦀
Browse files

Use the FILE_SHARE_DELETE flag for CreateFile on a mapping 

A comment by rransom on #8795 taken together with a comment by doorss
recorded on #2077 suggest that *every* attempt to replace the md cache
will fail on Vista/Win7 if we don't have the FILE_SHARE_DELETE flag
passed to CreateFile, and if we try to replace the file ourselves
before unmapping it.  I'm adding the FILE_SHARE_DELETE, since that's
this simplest fix.  Broken indexers (the favored #2077 hypothesis)
could still cause trouble here, but at least this patch should make us
stop stepping on our own feet.

Likely fix for #2077 and its numerous duplicates. Bugfix on
0.2.2.6-alpha, which first had a microdescriptor cache that would get
replaced before remapping it.
parent 4835faeb

changes/bug2077_share_delete

0 → 100644
+7 −0
Original line number Diff line number Diff line 
  o Major bugfixes (windows):

    - Open files to be mapped with FILE_SHARE_DELETE so that we can

      replace them before closing the mapping. This is a likely cause of

      warnings and crashes when replacing the microdescriptor cache

      file. Diagnosed based on comments by "doorss" and by Robert

      Ransom. Possible fix for bug 2077; bugfix on 0.2.2.6-alpha.

src/common/compat.c

+1 −1
Original line number Diff line number Diff line
@@ -238,7 +238,7 @@ tor_mmap_file(const char *filename) 
  strlcpy(tfilename,filename,MAX_PATH);

#endif

  file_handle = CreateFile(tfilename,

                           GENERIC_READ, FILE_SHARE_READ,

                           GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_DELETE,

                           NULL,

                           OPEN_EXISTING,

                           FILE_ATTRIBUTE_NORMAL,