[Libguestfs] [PATCH v2 1/2] launch: add internal helper for socket paths creation

[Richard W.M. Jones]

On Wed, Feb 03, 2016 at 01:17:41PM +0100, Pino Toscano wrote:
> Introduce an internal helper to create paths for sockets -- will be
> useful for changing later the logic for placing sockets.
> Futhermore, check that the length of sockets won't overflow the buffer
> for their filenames.
> ---
>  src/guestfs-internal.h |  1 +
>  src/launch-direct.c    |  4 +++-
>  src/launch-libvirt.c   | 10 ++++++----
>  src/launch.c           | 17 +++++++++++++++++
>  4 files changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h
> index 5ecd322..bff9f64 100644
> --- a/src/guestfs-internal.h
> +++ b/src/guestfs-internal.h
> @@ -782,6 +782,7 @@ extern void guestfs_int_launch_send_progress (guestfs_h *g, int perdozen);
>  extern char *guestfs_int_appliance_command_line (guestfs_h *g, const char *appliance_dev, int flags);
>  #define APPLIANCE_COMMAND_LINE_IS_TCG 1
>  const char *guestfs_int_get_cpu_model (int kvm);
> +int guestfs_int_create_socketname (guestfs_h *g, const char *filename, char (*sockname)[UNIX_PATH_MAX]);
>  extern void guestfs_int_register_backend (const char *name, const struct backend_ops *);
>  extern int guestfs_int_set_backend (guestfs_h *g, const char *method);
>  
> diff --git a/src/launch-direct.c b/src/launch-direct.c
> index b8e453d..a81d4b3 100644
> --- a/src/launch-direct.c
> +++ b/src/launch-direct.c
> @@ -295,7 +295,9 @@ launch_direct (guestfs_h *g, void *datav, const char *arg)
>    /* Using virtio-serial, we need to create a local Unix domain socket
>     * for qemu to connect to.
>     */
> -  snprintf (data->guestfsd_sock, sizeof data->guestfsd_sock, "%s/guestfsd.sock", g->tmpdir);
> +  if (guestfs_int_create_socketname (g, "guestfsd.sock",
> +                                     &data->guestfsd_sock) == -1)
> +    goto cleanup0;
>  
>    daemon_accept_sock = socket (AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
>    if (daemon_accept_sock == -1) {
> diff --git a/src/launch-libvirt.c b/src/launch-libvirt.c
> index 8a5d93e..376bd80 100644
> --- a/src/launch-libvirt.c
> +++ b/src/launch-libvirt.c
> @@ -395,8 +395,9 @@ launch_libvirt (guestfs_h *g, void *datav, const char *libvirt_uri)
>    /* Using virtio-serial, we need to create a local Unix domain socket
>     * for qemu to connect to.
>     */
> -  snprintf (data->guestfsd_path, sizeof data->guestfsd_path,
> -            "%s/guestfsd.sock", g->tmpdir);
> +  if (guestfs_int_create_socketname (g, "guestfsd.sock",
> +                                     &data->guestfsd_path) == -1)
> +    goto cleanup;
>  
>    set_socket_create_context (g);
>  
> @@ -421,8 +422,9 @@ launch_libvirt (guestfs_h *g, void *datav, const char *libvirt_uri)
>    }
>  
>    /* For the serial console. */
> -  snprintf (data->console_path, sizeof data->console_path,
> -            "%s/console.sock", g->tmpdir);
> +  if (guestfs_int_create_socketname (g, "console.sock",
> +                                     &data->console_path) == -1)
> +    goto cleanup;
>  
>    console_sock = socket (AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
>    if (console_sock == -1) {
> diff --git a/src/launch.c b/src/launch.c
> index f59818f..60f02a7 100644
> --- a/src/launch.c
> +++ b/src/launch.c
> @@ -418,6 +418,23 @@ guestfs_int_get_cpu_model (int kvm)
>  #endif
>  }
>  
> +/* Create the path for a socket with the selected filename in the
> + * tmpdir.
> + */
> +int
> +guestfs_int_create_socketname (guestfs_h *g, const char *filename,
> +                               char (*sockpath)[UNIX_PATH_MAX])
> +{
> +  if (strlen (g->tmpdir) + 1 + strlen (filename) > UNIX_PATH_MAX-1) {
> +    error (g, _("socket path too long: %s/%s"), g->tmpdir, filename);
> +    return -1;
> +  }
> +
> +  snprintf (*sockpath, UNIX_PATH_MAX, "%s/%s", g->tmpdir, filename);
> +
> +  return 0;
> +}
> +
>  /* glibc documents, but does not actually implement, a 'getumask(3)'
>   * call.  This implements a thread-safe way to get the umask.  Note
>   * this is only called when g->verbose is true and after g->tmpdir

Looks good, ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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