Re: [Qemu-devel] [PATCH 1/1] qemu-nbd: add the option to use pre-created server socket

[Eric Blake]

On 09/29/2016 06:02 AM, Denis V. Lunev wrote:
> From: Denis Plotnikov <address@hidden>
> 
> Originally NBD server socket was created by qemu-nbd code. This leads to
> the race when the management layer starts qemu-nbd server and allows a
> client to connect to the server. In this case there is a possibility that
> qemu-nbd does not open listening server socket yet. Creating listening
> socket before starting of qemu-ndb and passing socket fd via command line
> solves this issue completely.
> 
> Signed-off-by: Denis Plotnikov <address@hidden>
> Reviewed-by: Roman Kagan <address@hidden>
> Signed-off-by: Denis V. Lunev <address@hidden>
> CC: Paolo Bonzini <address@hidden>
> ---

> @@ -78,6 +79,7 @@ static void usage(const char *name)
>  "  -b, --bind=IFACE          interface to bind to (default `0.0.0.0')\n"
>  "  -k, --socket=PATH         path to the unix socket\n"
>  "                            (default '"SOCKET_PATH"')\n"
> +"  --server-sock-fd=NUM      pre-opened listening server socket file 
> descriptor\n"
>  "  -e, --shared=NUM          device can be shared by NUM clients (default 
> '1')\n"

Looking at 'qemu-nbd --help', all other long-option-only options are
indented so that the -- line up to the same column (see for example
--cache and --aio).

>  
> -static SocketAddress *nbd_build_socket_address(const char *sockpath,
> +static SocketAddress *nbd_build_sock_fd(const char *sockpath,
>                                                 const char *bindto,
>                                                 const char *port)

Indentation now looks off.

> +static void setup_address_and_port(const char **address, const char **port)
> +{
> +    if (*address == NULL) {
> +        *address = "0.0.0.0";
> +    }
> +
> +    if (*port == NULL) {
> +        *port = g_strdup_printf("%d", NBD_DEFAULT_PORT);;

s/;;/;/

Why is one of these parameters malloc'd, but the other pointing to const
storage? Do you have a memory leak, or else a risk of corrupting
read-only memory?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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