[lxc-devel] [PATCH v2 5/7] pass namespace handles to the stop hook

[Wolfgang Bumiller]

> On September 30, 2015 at 6:07 PM Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> 
> 
> Quoting Wolfgang Bumiller (w.bumiller at proxmox.com):
> > Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
> > ---
> >  src/lxc/start.c | 21 +++++++++++++++++++--
> >  1 file changed, 19 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/lxc/start.c b/src/lxc/start.c
> > index a1eb961..38e7e97 100644
> > --- a/src/lxc/start.c
> > +++ b/src/lxc/start.c
> > @@ -486,15 +486,32 @@ out_free:
> >  
> >  void lxc_fini(const char *name, struct lxc_handler *handler)
> >  {
> > -	int i;
> > +	int i, rc;
> > +	pid_t self = getpid();
> > +	char **namespaces = (char**)malloc((LXC_NS_MAX+1) * sizeof(char*));
> > +	size_t namespace_count = 0;
> >  
> >  	/* The STOPPING state is there for future cleanup code
> >  	 * which can take awhile
> >  	 */
> >  	lxc_set_state(name, handler, STOPPING);
> >  
> > -	if (run_lxc_hooks(name, "stop", handler->conf, handler->lxcpath, NULL))
> > +	for (i = 0; i < LXC_NS_MAX; i++) {
> > +		if (handler->nsfd[i] != -1) {
> 
> Hm, wait - what happens if handler->nsfd[i] == -1?  I.e. if there is no
> network
> namespace.  namespaces[i] will be undefined, right?

Yes, which is why I index by `namespace_count` and not `i` both when print()ing
as well as free()ing, and set the last [namespace_count] index to NULL as that's
how run_script_argv() finds the end.

But, I don't free(namespaces) which is rather embarrassing... (actually
the embarrassing part is allocating it with malloc() in the first place)
I should just:
-+	char **namespaces = (char**)malloc((LXC_NS_MAX+1) * sizeof(char*));
++	char *namespaces[LXC_NS_MAX+1];

> > +			rc = asprintf(&namespaces[namespace_count], "%s:/proc/%d/fd/%d",
> > +			              ns_info[i].proc_name, self, handler->nsfd[i]);
> > +			if (rc == -1) {
> > +				SYSERROR("failed to allocate memory");
> > +				break;
> > +			}
> > +			++namespace_count;
> > +		}
> > +	}
> > +	namespaces[namespace_count] = NULL;
> > +	if (run_lxc_hooks(name, "stop", handler->conf, handler->lxcpath,
> > namespaces))
> >  		ERROR("failed to run stop hooks for container '%s'.", name);
> > +	while (namespace_count--)
> > +		free(namespaces[namespace_count]);
> >  	for (i = 0; i < LXC_NS_MAX; i++) {
> >  		if (handler->nsfd[i] != -1) {
> >  			close(handler->nsfd[i]);
> > -- 
> > 2.1.4
> > 
> > 
> > _______________________________________________
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> > lxc-devel at lists.linuxcontainers.org
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