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Re: [PATCH 1/5] Use protected visibility for _rtld_global and _rtld_global_ro
- From: Nix <nix at esperi dot org dot uk>
- To: Richard Henderson <rth at twiddle dot net>
- Cc: Peter Collingbourne <pcc at google dot com>, libc-alpha at sourceware dot org
- Date: Mon, 13 May 2013 17:42:17 +0100
- Subject: Re: [PATCH 1/5] Use protected visibility for _rtld_global and _rtld_global_ro
- References: <1368459372-2415-1-git-send-email-pcc at google dot com> <1368459372-2415-2-git-send-email-pcc at google dot com> <51911545 dot 6060907 at twiddle dot net>
On 13 May 2013, Richard Henderson said:
> On 05/13/2013 08:36 AM, Peter Collingbourne wrote:
>> _rtld_local was created back in 2002 (see commit 0d01dac), and the
>> protected attribute removed on _rtld_global, for an undocumented
>> reason...
>
> Protected visibility requires more runtime overhead in the dynamic linker.
Quite. Anyone outside libc accessing it is a lunatic who deserves what
they get (speaking as someone who wrote code doing just that last month)
and who one hopes, knows what they are doing, and is unlikely to be put
off by a little peccadillo like protected visibility. So you're paying a
measurable cost for no real gain.
--
NULL && (void)