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

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) {