Re: [Openvpn-devel] Opened file descriptors in script calls

[James Y. <ji...@yo...>]

Aaron Sethman <and...@ra...> said:

> On Mon, 10 Feb 2003, Alberto Gonzalez Iniesta wrote:
> 
> >
> > Hi,
> >
> > Again, I'm no C hacker, but I think this should be better:
> >
> > for(x = 3; x < 100; x++)
> >
> > Since the first 3 fds (stdin, stdout and stderr) should be kept open.
> >
> Wasn't sure if stdin, stdout and stderr needed to be left open or not in
> this case.  Obviously this is an easy fix :)

Actually, I was just thinking what a pain to have to reimplement system() just
to close a few fds.  There must be a better way, and as it turns out, there is:

/* Set a file descriptor to not be passed across execs */
void
set_cloexec (int fd)
{
  if (fcntl (fd, F_SETFD, FD_CLOEXEC) < 0)
    msg (M_ERR, "Set file descriptor to FD_CLOEXEC failed");
}

Just set the FD_CLOEXEC flag on the fd and it won't be passed across the exec
that runs the shell.

I already wrote the patch and it's in the CVS.

James