Re: fcntl(F_SETFD) on a file or socket handle

[Corinna Vinschen <cygwin at cygwin dot com>]

On Tue, Sep 18, 2001 at 03:48:22PM +0900, Dmitry Timoshkov wrote:
> Hello.
> 
> Just want report a serious bug in Cygwin.
> 
> Many applications use this construct in their code:
> fcntl(fd, F_SETFD, 1); /* set close on exec flag */
> 
> fcntl(fd) below is a replacement for the above construct,
> fd - file/socket descriptor, resulted from an open() or a socket() call.
> 
> Some symptoms:
> 
> 1. If an fd is a socket and fcntl(fd) is called right after the connect(fd) call,
> connection will get broken.
> 
> 2. If an fd is transferred via a pipe end and fcntl(fd) is called right after
> write(pipe, &fd, sizeof(fd)) call, the another pipe end will receive an invalid
> fd handle.
> 
> If in the both cases above add sleep(1) before fcntl(fd), then all works without
> a failure.
> 
> I didn't investigate it further, and probably will not have time in the near
> future to do so. Sorry.

:-(

You could at least send a testcase if you don't want to debug it.

Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin@cygwin.com
Red Hat, Inc.

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