Re: [libvirt] PATCH: 1/7: Removing state from lxc_vm_t
On Mon, Aug 11, 2008 at 12:50:46PM +0200, Jim Meyering wrote:
"Daniel P. Berrange" <berrange(a)redhat.com> wrote:
> This patch does some simple re-factoring of the way the TTYs and
> control socket are handled to reduce the amount of state stored
> in the lxc_vm_t structure, in preparation for the switchover to
> the generic domain handling APIs.
One more thing:
...
> diff -r 63b8398c302e src/lxc_container.c
> --- a/src/lxc_container.c Mon Jul 14 12:18:23 2008 +0100
> +++ b/src/lxc_container.c Tue Jul 15 11:55:48 2008 +0100
...
> - close(0); close(1); close(2);
> + /* Just in case someone forget to set FD_CLOEXEC, explicitly
> + * close all FDs before executing the container */
> + open_max = sysconf (_SC_OPEN_MAX);
> + for (i = 0; i < open_max; i++)
> + if (i != ttyfd)
> + close(i);
Do you really need to close all file descriptors > 2 ?
I seem to recall that an application doing this caused trouble
when it closed a file descriptor (opened via the shell that I
was using for log output.
This is important to ensuring no file descriptors are leaked into the
container we run because that would be a potential security problem.
In any case this code will be replaced by a call to virExec() by a
later patch in this series.
Daniel
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