TCL exec kills its owning tty (was: Unable to initialize fd 0 for /dev/tty1)
On 9/6/2010 11:34 PM, Ryan Johnson wrote: The last couple days I've gotten some really strange errors. Sometimes I'll alt-tab to an xterm window and start typing, only to have it disappear at the first keystroke. Sometimes `emacs -nw' will get hit instead, leaving both emacs and the xterm pretty much unusable. I haven't been able to get a stack trace I can reproduce this bug reliably with both 1.7.7 and 1.7.6 versions of cygwin1.dll (which makes me suspect the problem is not there). The reason I couldn't get a stack trace is because the xterm doesn't receive an error... it just gets an EOF and dutifully exits. Sometimes you can see 'exit' appear just before the window closes. After some digging, it looks like TCL is the culprit (recall I was running tkdiff). Here's a minimal test case, which will close its controlling tty when it exits: $ echo 'exec ls' tty-killer; tclsh tty-killer Running the script in the foreground, passing it as a -c argument to bash, or piping it into tclsh, does *not* expose the bug. Ideas? Ryan -- 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
Re: TCL exec kills its owning tty (was: Unable to initialize fd 0 for /dev/tty1)
On Sep 7 11:22, Ryan Johnson wrote: On 9/6/2010 11:34 PM, Ryan Johnson wrote: The last couple days I've gotten some really strange errors. Sometimes I'll alt-tab to an xterm window and start typing, only to have it disappear at the first keystroke. Sometimes `emacs -nw' will get hit instead, leaving both emacs and the xterm pretty much unusable. I haven't been able to get a stack trace I can reproduce this bug reliably with both 1.7.7 and 1.7.6 versions of cygwin1.dll (which makes me suspect the problem is not there). Actually, this is a Cygwin bug. I can reproduce it and I can only reproduce it starting with Cygwin 1.7.6, which introduced a change in the way ttys are handled under the hood. Apparently I managed to break something along the line. $ echo 'exec ls' tty-killer; tclsh tty-killer Running the script in the foreground, passing it as a -c argument to bash, or piping it into tclsh, does *not* expose the bug. Unfortunately it also doesn't happen under strace. So, still digging for the culprit. Stay tuned... 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
