From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11846 Path: news.gmane.org!.POSTED!not-for-mail From: Hauke Mehrtens Newsgroups: gmane.linux.kernel.api,gmane.linux.kernel,gmane.linux.lib.musl.general Subject: Re: [PATCHv3] uapi libc compat: add fallback for unsupported libcs Date: Sat, 26 Aug 2017 22:31:21 +0200 Message-ID: <26584c95-dba0-6a70-0ac6-cd9041b1a983@hauke-m.de> References: <20170729140259.GA28081@nyan> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1503779498 4461 195.159.176.226 (26 Aug 2017 20:31:38 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 26 Aug 2017 20:31:38 +0000 (UTC) To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, musl-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org, "David S. Miller" , Carlos O'Donell Original-X-From: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Sat Aug 26 22:31:33 2017 Return-path: Envelope-to: glka-linux-api@m.gmane.org Original-Received: from vger.kernel.org ([209.132.180.67]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dlhjn-0000Un-Of for glka-linux-api@m.gmane.org; Sat, 26 Aug 2017 22:31:24 +0200 Original-Received: (majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org) by vger.kernel.org via listexpand id S1751085AbdHZUb2 (ORCPT ); Sat, 26 Aug 2017 16:31:28 -0400 Original-Received: from mx1.mailbox.org ([80.241.60.212]:56992 "EHLO mx1.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751083AbdHZUb1 (ORCPT ); Sat, 26 Aug 2017 16:31:27 -0400 Original-Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.mailbox.org (Postfix) with ESMTPS id 0FC8942982; Sat, 26 Aug 2017 22:31:24 +0200 (CEST) X-Virus-Scanned: amavisd-new at heinlein-support.de Original-Received: from smtp1.mailbox.org ([80.241.60.240]) by spamfilter02.heinlein-hosting.de (spamfilter02.heinlein-hosting.de [80.241.56.116]) (amavisd-new, port 10030) with ESMTP id SCPxWAwdit_Q; Sat, 26 Aug 2017 22:31:22 +0200 (CEST) In-Reply-To: <20170729140259.GA28081@nyan> Content-Language: en-US Original-Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Precedence: bulk List-ID: X-Mailing-List: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Xref: news.gmane.org gmane.linux.kernel.api:24590 gmane.linux.kernel:2558205 gmane.linux.lib.musl.general:11846 Archived-At: On 07/29/2017 04:02 PM, 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. > > 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. > > 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. > > This commit together with the musl libc commit > > http://git.musl-libc.org/cgit/musl/commit/?id=04983f2272382af92eb8f8838964ff944fbb8258 > > fixes for example the following compiler errors when is > included after musl's : > > ./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' > > Signed-off-by: Felix Janda Reviewed-by: Hauke Mehrtens With this patch + a patch which protects "struct ethhdr" I was able to build LEDE with musl libc using these kernel headers without a problem include building iproute2. I would like to send my patch to protect "struct ethhdr", but it depends ion this one. > --- > 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(-) > > diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h > index 44b8a6bd5fe1..65db6b26d790 100644 > --- a/include/uapi/linux/libc-compat.h > +++ b/include/uapi/linux/libc-compat.h > @@ -167,46 +167,99 @@ > > /* 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__) */ > > /* 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 > > /* 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 > > /* 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 > > /* 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 > > /* Definitions for xattr.h */ > +#ifndef __UAPI_DEF_XATTR > #define __UAPI_DEF_XATTR 1 > +#endif > > #endif /* __GLIBC__ */ > >