[libvirt] [PATCH] Ensure virExec preserves logging environment

[Daniel P. Berrange]

On Mon, Nov 22, 2010 at 12:01:00PM -0700, Eric Blake wrote:
> On 11/22/2010 07:11 AM, Daniel P. Berrange wrote:
> > The virFork call resets all logging handlers that may have been
> > set. Re-enable them after fork in virExec, so that env variables
> > fir LIBVIRT_LOG_OUTPUTS and LIBVIRT_LOG_FILTERS take effect
> > until the execve()
> > 
> > * src/util/util.c: Preserve logging in child in virExec
> > ---
> >  src/util/util.c |    6 ++++++
> >  1 files changed, 6 insertions(+), 0 deletions(-)
> > 
> > diff --git a/src/util/util.c b/src/util/util.c
> > index f2fe58a..a0849e1 100644
> > --- a/src/util/util.c
> > +++ b/src/util/util.c
> > @@ -602,6 +602,9 @@ __virExec(const char *const*argv,
> >          childout = -1;
> >      }
> >  
> > +    /* Initialize full logging for a while */
> > +    virLogSetFromEnv();
> 
> Should this function be changed to take a bool parameter for marking
> logging fd's as cloexec?  Or, for that matter, should all logging fd's
> always be cloexec in the first place?

Yes, everything libvirt does should be O_CLOEXEC really.

> > +
> >      /* Daemonize as late as possible, so the parent process can detect
> >       * the above errors with wait* */
> >      if (flags & VIR_EXEC_DAEMON) {
> > @@ -650,6 +653,9 @@ __virExec(const char *const*argv,
> >          virClearCapabilities() < 0)
> >          goto fork_error;
> >  
> > +    /* Close logging again to ensure no FDs leak to child */
> > +    virLogReset();
> 
> In which case we wouldn't need this, because the fds would then
> automatically avoid leaking?

I prefer to be paranoid about closing FDs even if we believe
they are all O_CLOEXEC already.

Daniel