Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751856AbdLCL2a (ORCPT ); Sun, 3 Dec 2017 06:28:30 -0500 Received: from vmicros1.altlinux.org ([194.107.17.57]:35166 "EHLO vmicros1.altlinux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994AbdLCL22 (ORCPT ); Sun, 3 Dec 2017 06:28:28 -0500 Date: Sun, 3 Dec 2017 14:28:25 +0300 From: "Dmitry V. Levin" To: Felix Janda Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, musl@lists.openwall.com, Hauke Mehrtens , "David S. Miller" , "Carlos O'Donell" , Florian Fainelli Subject: Re: [PATCHv3 resend] uapi libc compat: add fallback for unsupported libcs Message-ID: <20171203112825.GA452@altlinux.org> Mail-Followup-To: Felix Janda , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, musl@lists.openwall.com, Hauke Mehrtens , "David S. Miller" , Carlos O'Donell , Florian Fainelli References: <20171112183017.GA8431@nyan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="OXfL5xGRrasGEqWY" Content-Disposition: inline In-Reply-To: <20171112183017.GA8431@nyan> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6454 Lines: 190 --OXfL5xGRrasGEqWY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Sun, Nov 12, 2017 at 01:30:17PM -0500, Felix Janda wrote: > libc-compat.h aims to prevent symbol collisions between uapi and libc > headers for each supported libc. This requires continuous coordination > between them. >=20 > The goal of this commit is to improve the situation for libcs (such as > musl) which are not yet supported and/or do not wish to be explicitly > supported, while not affecting supported libcs. More precisely, with > this commit, unsupported libcs can request the suppression of any > specific uapi definition by defining the correspondings _UAPI_DEF_* > macro as 0. This can fix symbol collisions for them, as long as the > libc headers are included before the uapi headers. Inclusion in the > other order is outside the scope of this commit. >=20 > All infrastructure in order to enable this fallback for unsupported > libcs is already in place, except that libc-compat.h unconditionally > defines all _UAPI_DEF_* macros to 1 for all unsupported libcs so that > any previous definitions are ignored. In order to fix this, this commit > merely makes these definitions conditional. >=20 > This commit together with the musl libc commit >=20 > http://git.musl-libc.org/cgit/musl/commit/?id=3D04983f2272382af92eb8f8838= 964ff944fbb8258 >=20 > fixes for example the following compiler errors when is > included after musl's : >=20 > ./linux/in6.h:32:8: error: redefinition of 'struct in6_addr' > ./linux/in6.h:49:8: error: redefinition of 'struct sockaddr_in6' > ./linux/in6.h:59:8: error: redefinition of 'struct ipv6_mreq' >=20 > Signed-off-by: Felix Janda > Reviewed-by: Hauke Mehrtens > --- > v3: Fix typos, add a comment to the file and use #ifndef. > v2: The only change to the previous version is the commit title and > message. > --- > include/uapi/linux/libc-compat.h | 55 ++++++++++++++++++++++++++++++++++= +++++- > 1 file changed, 54 insertions(+), 1 deletion(-) >=20 > diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-c= ompat.h > index 44b8a6bd5fe1..65db6b26d790 100644 > --- a/include/uapi/linux/libc-compat.h > +++ b/include/uapi/linux/libc-compat.h > @@ -167,46 +167,99 @@ > =20 > /* If we did not see any headers from any supported C libraries, > * or we are being included in the kernel, then define everything > - * that we need. */ > + * that we need. Check for previous __UAPI_* definitions to give > + * unsupported C libraries a way to opt out of any kernel definition. */ > #else /* !defined(__GLIBC__) */ > =20 > /* Definitions for if.h */ > +#ifndef __UAPI_DEF_IF_IFCONF > #define __UAPI_DEF_IF_IFCONF 1 > +#endif > +#ifndef __UAPI_DEF_IF_IFMAP > #define __UAPI_DEF_IF_IFMAP 1 > +#endif > +#ifndef __UAPI_DEF_IF_IFNAMSIZ > #define __UAPI_DEF_IF_IFNAMSIZ 1 > +#endif > +#ifndef __UAPI_DEF_IF_IFREQ > #define __UAPI_DEF_IF_IFREQ 1 > +#endif > /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ > +#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS > #define __UAPI_DEF_IF_NET_DEVICE_FLAGS 1 > +#endif > /* For the future if glibc adds IFF_LOWER_UP, IFF_DORMANT and IFF_ECHO */ > +#ifndef __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO > #define __UAPI_DEF_IF_NET_DEVICE_FLAGS_LOWER_UP_DORMANT_ECHO 1 > +#endif Please double-check that mentioning glibc in comments of this !__GLIBC__ section is relevant. > =20 > /* Definitions for in.h */ > +#ifndef __UAPI_DEF_IN_ADDR > #define __UAPI_DEF_IN_ADDR 1 > +#endif > +#ifndef __UAPI_DEF_IN_IPPROTO > #define __UAPI_DEF_IN_IPPROTO 1 > +#endif > +#ifndef __UAPI_DEF_IN_PKTINFO > #define __UAPI_DEF_IN_PKTINFO 1 > +#endif > +#ifndef __UAPI_DEF_IP_MREQ > #define __UAPI_DEF_IP_MREQ 1 > +#endif > +#ifndef __UAPI_DEF_SOCKADDR_IN > #define __UAPI_DEF_SOCKADDR_IN 1 > +#endif > +#ifndef __UAPI_DEF_IN_CLASS > #define __UAPI_DEF_IN_CLASS 1 > +#endif > =20 > /* Definitions for in6.h */ > +#ifndef __UAPI_DEF_IN6_ADDR > #define __UAPI_DEF_IN6_ADDR 1 > +#endif > +#ifndef __UAPI_DEF_IN6_ADDR_ALT > #define __UAPI_DEF_IN6_ADDR_ALT 1 > +#endif > +#ifndef __UAPI_DEF_SOCKADDR_IN6 > #define __UAPI_DEF_SOCKADDR_IN6 1 > +#endif > +#ifndef __UAPI_DEF_IPV6_MREQ > #define __UAPI_DEF_IPV6_MREQ 1 > +#endif > +#ifndef __UAPI_DEF_IPPROTO_V6 > #define __UAPI_DEF_IPPROTO_V6 1 > +#endif > +#ifndef __UAPI_DEF_IPV6_OPTIONS > #define __UAPI_DEF_IPV6_OPTIONS 1 > +#endif > +#ifndef __UAPI_DEF_IN6_PKTINFO > #define __UAPI_DEF_IN6_PKTINFO 1 > +#endif > +#ifndef __UAPI_DEF_IP6_MTUINFO > #define __UAPI_DEF_IP6_MTUINFO 1 > +#endif > =20 > /* Definitions for ipx.h */ > +#ifndef __UAPI_DEF_SOCKADDR_IPX > #define __UAPI_DEF_SOCKADDR_IPX 1 > +#endif > +#ifndef __UAPI_DEF_IPX_ROUTE_DEFINITION > #define __UAPI_DEF_IPX_ROUTE_DEFINITION 1 > +#endif > +#ifndef __UAPI_DEF_IPX_INTERFACE_DEFINITION > #define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1 > +#endif > +#ifndef __UAPI_DEF_IPX_CONFIG_DATA > #define __UAPI_DEF_IPX_CONFIG_DATA 1 > +#endif > +#ifndef __UAPI_DEF_IPX_ROUTE_DEF > #define __UAPI_DEF_IPX_ROUTE_DEF 1 > +#endif > =20 > /* Definitions for xattr.h */ > +#ifndef __UAPI_DEF_XATTR > #define __UAPI_DEF_XATTR 1 > +#endif > =20 > #endif /* __GLIBC__ */ As most of affected macros are related to networking (in fact, all except __UAPI_DEF_XATTR affect uapi/linux/{if.h,in.h,in6.h,ipv6.h,ipx.h} only), I think this patch should be submitted to netdev. --=20 ldv --OXfL5xGRrasGEqWY Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJaI9/ZAAoJEAVFT+BVnCUIiqoQAKEcGha6uTfMPfhC/QByBoCy 6Fphx4KtFVn4xWexzuEXrmm4ssAYj2ygZr4/REqjcKUgABoEXLEZNkvbzAUPxDgs LXRfEXxJ0NIVIZJA9VuW2/KgOZ3U+cLpyi7ZgP3W9hRrpdIPu1Gg/RQGykuwnMBK 6TgpY1tJ8x4KLv54BOvXaixWczbvLSR1RsVD1uN9wkpAM1f9N8kvVWEumu52COt5 gVhQ0LEBCULjcNwIvnLIuEh+savp3WLBk61xn7qUlUb98sokdg6+iuNK3pM205DF MbGDeDMUsjnfNdF7T2KE3DsLzqCWgVJRIasqfAjP0M7SaRkkLhA4Q1q7JOSpvEri mlBfeKxhkI3ElfCw1SiVG87FMCsMQu7yqwipW8KXpVLtC8FVyuCC6LY/hFh1peBa YpGy6zVu0YRjtmbk4D7TaBGqWDHXD83OrOZxat4L9g82CVIw3J2x9llzuuyZ+dYC s/snjxI2RsaKXQXs03DAtRf4itNDswzBkzbiO3DhYjEoH39J3yd4J5GrtE4wmUdv EQYYgZ4vxSfnYNzXaWk9EJgwKbuHP6ESeTte92PuOWImGifYMPsJdAV1O2bKVM0m 4g2ILMExWevOxURFt8Sn6MYEX+QiyfvfNdcUSUmrd2tWvwrs1nJXunjU4bnRrPac cE3ruYgGlSe5b35l4Xti =5P0Q -----END PGP SIGNATURE----- --OXfL5xGRrasGEqWY--