From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11699 Path: news.gmane.org!.POSTED!not-for-mail From: Felix Janda Newsgroups: gmane.linux.kernel.api,gmane.linux.lib.musl.general,gmane.linux.kernel Subject: Re: [musl] [PATCHv2] uapi libc compat: add fallback for unsupported libcs Followup-To: gmane.linux.kernel Date: Sat, 8 Jul 2017 17:44:02 -0400 Message-ID: <20170708214402.GA2742@nyan> References: <20170708202732.GA1891@nyan> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1499550353 22832 195.159.176.226 (8 Jul 2017 21:45:53 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 8 Jul 2017 21:45:53 +0000 (UTC) User-Agent: Mutt/1.7.2 (2016-11-26) Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "David S. Miller" , Carlos O'Donell To: musl-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org Original-X-From: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Sat Jul 08 23:45:49 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 1dTxXu-0005ZS-PU for glka-linux-api@m.gmane.org; Sat, 08 Jul 2017 23:45:47 +0200 Original-Received: (majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org) by vger.kernel.org via listexpand id S1751786AbdGHVpv (ORCPT ); Sat, 8 Jul 2017 17:45:51 -0400 Original-Received: from mout02.posteo.de ([185.67.36.66]:47875 "EHLO mout02.posteo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750883AbdGHVpu (ORCPT ); Sat, 8 Jul 2017 17:45:50 -0400 Original-Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id C0E5C20F09 for ; Sat, 8 Jul 2017 23:45:48 +0200 (CEST) Original-Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3x4lQg1M19zytZ; Sat, 8 Jul 2017 23:45:47 +0200 (CEST) Mail-Followup-To: musl-ZwoEplunGu1jrUoiu81ncdBPR1lH4CV8@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "David S. Miller" , Carlos O'Donell Content-Disposition: inline In-Reply-To: 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:23985 gmane.linux.lib.musl.general:11699 gmane.linux.kernel:2519381 Archived-At: Hauke Mehrtens wrote: > > > On 07/08/2017 10:27 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 > > Acked-by: Rich Felker > > --- > > v2: The only change to the previous version is the commit title and > > message. > > --- > > include/uapi/linux/libc-compat.h | 52 ++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 52 insertions(+) > > Does the documentation at the top of this file need some updates? I think that at least the comment preceding the part touched by this patch should be updated. I'm not sure how to update the documentation on top -- it does not say anything about unsupported libcs. > > diff --git a/include/uapi/linux/libc-compat.h b/include/uapi/linux/libc-compat.h > > index 44b8a6b..c316725 100644 > > --- a/include/uapi/linux/libc-compat.h > > +++ b/include/uapi/linux/libc-compat.h > > @@ -171,42 +171,94 @@ > > #else /* !defined(__GLIBC__) */ > > Why don't you used #ifndef ? It seemed more consistent with the rest of the file, which also uses "#if defined(...)" instead of "#ifdef". On the other hand, there are two uses of "#ifndef" in the file. I do not have any strong opinion on this. > > /* Definitions for if.h */ > > +#if !defined(__UAPI_DEF_IF_IFCONF) > > #define __UAPI_DEF_IF_IFCONF 1 > > +#endif > > +#if !defined(__UAPI_DEF_IF_IFMAP) > > #define __UAPI_DEF_IF_IFMAP 1 > > +#endif > > +#if !defined(__UAPI_DEF_IFNAMSIZ) > > This should be: > #if !defined( __UAPI_DEF_IF_IFNAMSIZ) > > > #define __UAPI_DEF_IF_IFNAMSIZ 1 > > +#endif > > +#if !defined(__UAPI_DEF_IFREQ) > > This should be: > #if !defined(__UAPI_DEF_IF_IFREQ) Thanks! Will be fixed in the next version. Felix > > #define __UAPI_DEF_IF_IFREQ 1 > > +#endif > > /* Everything up to IFF_DYNAMIC, matches net/if.h until glibc 2.23 */ > > +#if !defined(__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 */ > > +#if !defined(__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 */ > > +#if !defined(__UAPI_DEF_IN_ADDR) > > #define __UAPI_DEF_IN_ADDR 1 > > +#endif > > +#if !defined(__UAPI_DEF_IN_IPPROTO) > > #define __UAPI_DEF_IN_IPPROTO 1 > > +#endif > > +#if !defined(__UAPI_DEF_IN_PKTINFO) > > #define __UAPI_DEF_IN_PKTINFO 1 > > +#endif > > +#if !defined(__UAPI_DEF_IP_MREQ) > > #define __UAPI_DEF_IP_MREQ 1 > > +#endif > > +#if !defined(__UAPI_DEF_SOCKADDR_IN) > > #define __UAPI_DEF_SOCKADDR_IN 1 > > +#endif > > +#if !defined(__UAPI_DEF_IN_CLASS) > > #define __UAPI_DEF_IN_CLASS 1 > > +#endif > > > > /* Definitions for in6.h */ > > +#if !defined(__UAPI_DEF_IN6_ADDR) > > #define __UAPI_DEF_IN6_ADDR 1 > > +#endif > > +#if !defined(__UAPI_DEF_IN6_ADDR_ALT) > > #define __UAPI_DEF_IN6_ADDR_ALT 1 > > +#endif > > +#if !defined(__UAPI_DEF_SOCKADDR_IN6) > > #define __UAPI_DEF_SOCKADDR_IN6 1 > > +#endif > > +#if !defined(__UAPI_DEF_IPV6_MREQ) > > #define __UAPI_DEF_IPV6_MREQ 1 > > +#endif > > +#if !defined(__UAPI_DEF_IPPROTO_V6) > > #define __UAPI_DEF_IPPROTO_V6 1 > > +#endif > > +#if !defined(__UAPI_DEF_IPV6_OPTIONS) > > #define __UAPI_DEF_IPV6_OPTIONS 1 > > +#endif > > +#if !defined(__UAPI_DEF_IN6_PKTINFO) > > #define __UAPI_DEF_IN6_PKTINFO 1 > > +#endif > > +#if !defined(__UAPI_DEF_IP6_MTUINFO) > > #define __UAPI_DEF_IP6_MTUINFO 1 > > +#endif > > > > /* Definitions for ipx.h */ > > +#if !defined(__UAPI_DEF_SOCKADDR_IPX) > > #define __UAPI_DEF_SOCKADDR_IPX 1 > > +#endif > > +#if !defined(__UAPI_DEF_IPX_ROUTE_DEFINITION) > > #define __UAPI_DEF_IPX_ROUTE_DEFINITION 1 > > +#endif > > +#if !defined(__UAPI_DEF_IPX_INTERFACE_DEFINITION) > > #define __UAPI_DEF_IPX_INTERFACE_DEFINITION 1 > > +#endif > > +#if !defined(__UAPI_DEF_IPX_CONFIG_DATA) > > #define __UAPI_DEF_IPX_CONFIG_DATA 1 > > +#endif > > +#if !defined(__UAPI_DEF_IPX_ROUTE_DEF) > > #define __UAPI_DEF_IPX_ROUTE_DEF 1 > > +#endif > > > > /* Definitions for xattr.h */ > > +#if !defined(__UAPI_DEF_XATTR) > > #define __UAPI_DEF_XATTR 1 > > +#endif > > > > #endif /* __GLIBC__ */ > > > > --