[libvirt] [PATCH 5/8] Extend RPC protocol to allow FD passing

[Daniel P. Berrange]

On Fri, Oct 28, 2011 at 05:49:59AM -0600, Eric Blake wrote:
> On 10/28/2011 02:28 AM, Daniel P. Berrange wrote:
> >>>+    if ((fd = dup(msg->fds[slot]))<   0) {
> >>>+        virReportSystemError(errno,
> >>>+                             _("Unable to duplicate FD %d"),
> >>>+                             msg->fds[slot]);
> >>>+        return -1;
> >>>+    }
> >>
> >>Do we want to be using gnulib's dup_cloexec ("cloexec.h") or
> >>fcntl(fd, F_DUPFD_CLOEXEC, 0) here, so that our dup doesn't leak
> >>into a third-party child if we are linked into some larger
> >>multithreaded app?
> >
> >dup3() is the new glibc API for this ? Does gnulib support
> >that yet ?
> 
> Gnulib supports dup3().  But dup3() is not the same as dup(); it is
> the same as dup2().  That is:
> 
> dup(fd) maps to fcntl(fd, F_DUPFD_CLOEXEC,0) == dup_cloexec(fd)
> dup2(fd1, fd2) maps to dup3(fd1, fd2, O_CLOEXEC)

Ah ok, I see what you mean.


Daniel
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