[lxc-devel] [RFC 5/5] pass namespace handles to the stop hook

[Serge Hallyn]

Quoting Wolfgang Bumiller (w.bumiller at proxmox.com):
> ---
>  src/lxc/start.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/src/lxc/start.c b/src/lxc/start.c
> index a1eb961..7a909de 100644
> --- a/src/lxc/start.c
> +++ b/src/lxc/start.c
> @@ -486,15 +486,31 @@ 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) {
> +			rc = asprintf(&namespaces[namespace_count++], "%s:/proc/%d/fd/%d",
> +			              ns_info[i].proc_name, self, handler->nsfd[i]);

If asprintf fails, the contents of the first arg are undefined.  So iiuc
the error loop below, on error, will try to first free an undefined
value.    So I think the if (rc == -1) block needs to decrement namespace_count.

> +			if (rc == -1) {
> +				SYSERROR("failed to allocate memory");
> +				break;
> +			}
> +		}
> +	}
> +	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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