Re: [Libguestfs] [PATCH 1/8] New API: btrfs_subvolume_get_default

Richard W.M. Jones
Fri, 05 Dec 2014 12:27:06 -0000

On Tue, Dec 02, 2014 at 05:33:31PM +0800, Hu Tao wrote:
> +  ADD_ARG (argv, i, str_btrfs);
> +  ADD_ARG (argv, i, "subvolume");
> +  ADD_ARG (argv, i, "get-default");
> +  ADD_ARG (argv, i, fs_buf);
> +  ADD_ARG (argv, i, NULL);
> +
> +  r = commandv (&out, &err, argv);
> +  if (r == -1) {
> +    reply_with_error ("%s: %s", mountpoint, err);
> +    return -1;
> +  }
> +  r = xstrtol (out + 2, NULL, 10, &ret, NULL);

Unfortunately even gnulib's "xstrtol" function is a minefield, and
the
code above won't work [specifically -- it's insecure] on 32 bit
machines.

Anyway, I think it's better to use sscanf here, so:

  if (sscanf (out, "ID %" SCNi64, &ret) != 2) {
     // error ...
  }

> +  if (r != LONGINT_OK) {
> +    reply_with_error ("%s: could not parse subvolume id: %s.",
argv[0], out);
> +    return -1;
> +  }
> +
> +  return ret;
> +}
> +
>  int
>  do_btrfs_filesystem_sync (const char *fs)
>  {
> diff --git a/generator/actions.ml b/generator/actions.ml
> index 385b620..80c7ea7 100644
> --- a/generator/actions.ml
> +++ b/generator/actions.ml
> @@ -12027,6 +12027,15 @@ Set readahead (in 512-byte sectors) for the
device.
>
>  This uses the L<blockdev(8)> command." };
>
> +  { defaults with
> +    name = "btrfs_subvolume_get_default";
> +    style = RInt64 "id", [Pathname "mountpoint"], [];
> +    proc_nr = Some 425;
> +    optional = Some "btrfs"; camel_name =
"BTRFSSubvolumeGetDefault";
> +    shortdesc = "get the default subvolume or snapshot of a
filesystem";
> +    longdesc = "\
> +Get the default subvolume or snapshot of a filesystem mounted at
C<mountpoint>." };
> +

All of these APIs need tests.

Rich.

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