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

[Richard W.M. Jones]

On Fri, Dec 05, 2014 at 12:27:06PM +0000, Richard W.M. Jones wrote:
> 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) {

                                          ^^^^^
I mean != 1

Rich.

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