840435 - PR_APPEND is racy on windows

Status: NEW

(NSPR :: NSPR, defect)

Description

[Mike Hommey [:glandium]]

On Windows, _PR_HAVE_O_APPEND is not defined, so PR_Write does a PR_Seek64(fd, 0, PR_SEEK_END) before doing the actual write. This is racy when multiple threads or processes append to the same file. Instead, CreateFile should be called with FILE_APPEND_DATA.

http://msdn.microsoft.com/en-us/library/aa363858%28VS.85%29.aspx

Comment 1

[Wan-Teh Chang]

Thank you for the bug report. I worked on this before in bug 545650
and even wrote a patch (bug 545650 comment 81). But I abandoned
that patch after I discovered a problem with FILE_APPEND_DATA
(see bug 545650 comment 87).

I also found an alternative solution (bug 545650 comment 83), but
I didn't pursue that.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee is inactive on Bugzilla, so the assignee is being reset.