I've never used Safe before, but I thought I'd take a crack.

After I figured out which opcode is for the error (rv2gv, which is in :base_orig), I was getting:

'private value' trapped by operation mask...

[download]

So I found out which one took care of that (padany also in :base_orig):

use strict;
use warnings;

use Safe;
my $box = new Safe;

$box->permit_only(
    ':base_core', 
    'rv2gv',      # ref to glob cast
    'padany'      # private variable
);

my $vi = $box->reval('5',1);
die "$@ " unless (defined $vi);
print "vi=$vi\n";

[download]

Output:

vi=5

[download]

Note that the above can be simplified at the cost of allowing a bunch more opcodes implicitly:

$box->permit_only(':base_core', ':base_orig');

[download]

While doing some searching after figuring out the solution, I came across this: Perl opcode list.

In reply to Re: What additional ops needed for Safe::reval ? by stevieb
in thread What additional ops needed for Safe::reval ? by RonW

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.