On Sep 14 22:09, John Carey wrote: > On Sep 14 09:11, Corinna Vinschen wrote: > > I applied the below patch to Cygwin CVS and it appears to work nicely. > > The only potential race I can think of is, if another thread of the same > > Cygwin process calls SetCurrentDirectory. I'm inclined to let this > > situation slip through the cracks since SetCurrentDirectory will already > > mess up a mixed-mode Cygwin process. > > > > The "wincap.has_transactions ()" is just for testing. If we can use > > that code, I would replace is with something like > > "wincap.has_messed_up_cwd_handling()" or so. > ... > > I would argue against introducing a race with threads that call > SetCurrentDirectory(), for at least the following reasons: > > 1. The race can be avoided without too much grief.
Right. Still, the licensing issue... > 2. If a program does violate the rule against calling > SetCurrentDirectory() directly (possibly because of > some third party DLL being involved), then it could be > very difficult to detect the source of the resulting problems. But we're talking about mixed-mode Cygwin apps. They should use the Win32 API with care anyway. And the disconnection between SetCurrentDirectory and chdir already exists if the latter is called at all. > [...] > 3. The unknown. Hard to argue aginst *that*... > Anyway, one other detail: > > Are races within a pure-Cygwin program are prevented by > "cwd_lock"? I don't see it being locked yet, just initialized. > Perhaps the cwdstuff::set patch is not yet written? There's a cwd_lock.acquire and a cwd_lock.release call in cwdstuff::set. There's no such lock when cwdstuff::override_win32_cwd is called from cwdstuff::init, because at the time init is called there's no other concurrent thread running, except for the signal thread. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
