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Re: Official Linux system wrapper library?
- From: Florian Weimer <fweimer at redhat dot com>
- To: Dave Martin <Dave dot Martin at arm dot com>
- Cc: Andy Lutomirski <luto at amacapital dot net>, Daniel Colascione <dancol at google dot com>, "Michael Kerrisk \(man-pages\)" <mtk dot manpages at gmail dot com>, linux-kernel <linux-kernel at vger dot kernel dot org>, Joel Fernandes <joelaf at google dot com>, Linux API <linux-api at vger dot kernel dot org>, Willy Tarreau <w at 1wt dot eu>, Vlastimil Babka <vbabka at suse dot cz>, Carlos O'Donell <carlos at redhat dot com>, "libc-alpha\@sourceware.org" <libc-alpha at sourceware dot org>
- Date: Wed, 14 Nov 2018 12:40:44 +0100
- Subject: Re: Official Linux system wrapper library?
- References: <CAKOZuesB4R=dCz4merWQN0FSCGrXmOgUUr4ienSbStBJguNv8g@mail.gmail.com> <email@example.com> <firstname.lastname@example.org> <CAKOZues5SEESpJU=6MDTrPXTA1KTZFGNQE4Lw4t0fO-WBTU62w@mail.gmail.com> <email@example.com> <CAKOZuetdgk1QYhx1538-98rFpogMin=8DkPnCtU9_=ip23Vk7w@mail.gmail.com> <20181113193859.GJ3505@e103592.cambridge.arm.com> <69B07026-5E8B-47FC-9313-E51E899FAFB0@amacapital.net> <20181114105449.GK3505@e103592.cambridge.arm.com>
* Dave Martin:
> Fair points, though this is rather what I meant by "sane essentials".
> Because there are strict limits on what can be done in the vDSO, it may
> be more bloat-resistant and more conservatively maintained.
> This might provide a way to push some dumb compatibility kludge code
> that receives little ongoing maintenance outside the privilege wall,
> whereas it has to sit in the kernel proper today.
> In theory we could opt to advertise new syscalls only via vDSO entry
> points, and not maintain __NR_xxx values for them (which may or may
> not upset ptrace users.) Anyway, I digress...
Is the vDSO available across all architectures? (I don't think we use
it on all architectures in glibc.)
If not, a vDSO-based approach would merely lead to even more variance
between architectures, which can't be a good thing.