Re: Report: Threaded udevd

[Scott James Remnant <scott@canonical.com>]

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On Wed, 2008-10-22 at 17:12 +0100, Alan Jenkins wrote:

> > The pipe2() syscall allows you to specify flags for the returned file
> > descriptors:
> >
> > 	pipe2 (&fds, O_CLOEXEC)
> >   
> 
> Ah!  I see how it's supposed to be used now.
> 
> pipe2 (&fds, O_CLOEXEC)
> if (fork() == 0) {
>    dup2(&fds[WRITE_END], STDOUT_FILENO);
>    /* insert call to fcntl to remove O_CLOEXEC */
>    exec(program_name);
> 
You don't need the call to fcntl.  From the dup2(2) manpage:

       The two descriptors do not share file descriptor flags  (the  close-on-
       exec  flag).  The close-on-exec flag (FD_CLOEXEC; see fcntl(2)) for the
       duplicate descriptor is off.

So after you dup2() the writing end to standard output, standard output
will not be closed on exec.

Scott
-- 
Scott James Remnant
scott@canonical.com

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