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Re: [PATCH v4 0/3] Fix {recv,send}{m}msg standard compliance (BZ#16919)

From: Florian Weimer <fweimer at redhat dot com>
To: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>, libc-alpha at sourceware dot org
Date: Wed, 8 Jun 2016 10:35:55 +0200
Subject: Re: [PATCH v4 0/3] Fix {recv,send}{m}msg standard compliance (BZ#16919)
Authentication-results: sourceware.org; auth=none
References: <1459175641-12520-1-git-send-email-adhemerval dot zanella at linaro dot org>

On 03/28/2016 04:33 PM, Adhemerval Zanella wrote:

This patchset fixes BZ#16919, recvmsg standard compliance, where Linux
and POSIX differs in the msghdr and mmsghdr internal struct sizes.
The issue is POSIX defines [1] both msghdr.msg_namelen, msghdr.controllen,
and cmsghdr.cmsg_len as socklen_t, where Linux uses size_t.  So for 64-bits
architectures where size_t is larger sockelen_t it leads to standard
inconsistence.  Linux also added recvmmsg and sendmmsg, which uses a
composite struct based on msghdr (mmsghdr).

This patchset breaks various network emulation libraries becauseapplications use the new struct msghdr definition, yet dlsym (RTLD_NEXT,"recvmsg") picks the compat implementation.

Is this breakage really worth increased standards compliance? I thinkwe should roll this back before the 2.24 release and simply document thedeviation from POSIX.


Florian

Follow-Ups:
- Re: [PATCH v4 0/3] Fix {recv,send}{m}msg standard compliance (BZ#16919)
  - From: Joseph Myers

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