From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/4437 Path: news.gmane.org!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: stat64 on mips Date: Mon, 30 Dec 2013 17:13:41 -0500 Message-ID: <20131230221341.GN24286@brightrain.aerifal.cx> References: <20131230212953.GL24286@brightrain.aerifal.cx> <20131230220339.GM24286@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1388441633 13218 80.91.229.3 (30 Dec 2013 22:13:53 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 30 Dec 2013 22:13:53 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-4441-gllmg-musl=m.gmane.org@lists.openwall.com Mon Dec 30 23:14:00 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1Vxl5u-0000cx-RY for gllmg-musl@plane.gmane.org; Mon, 30 Dec 2013 23:13:54 +0100 Original-Received: (qmail 5357 invoked by uid 550); 30 Dec 2013 22:13:54 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 5349 invoked from network); 30 Dec 2013 22:13:53 -0000 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Xref: news.gmane.org gmane.linux.lib.musl.general:4437 Archived-At: On Mon, Dec 30, 2013 at 10:10:59PM +0000, Justin Cormack wrote: > On Mon, Dec 30, 2013 at 10:03 PM, Rich Felker wrote: > > On Mon, Dec 30, 2013 at 10:02:19PM +0000, Justin Cormack wrote: > >> On Mon, Dec 30, 2013 at 9:29 PM, Rich Felker wrote: > >> > On Mon, Dec 30, 2013 at 06:20:46PM +0000, Justin Cormack wrote: > >> >> MIPS is the most confusing architecture, but as far as I can make out, > >> >> the definition of struct stat64 that Musl has is probably the right > >> >> one for mips n32 but wrong for mips o32 which should be > >> >> > >> >> struct stat { > >> >> unsigned long st_dev; > >> >> unsigned long __st_pad0[3]; > >> >> unsigned long long st_ino; > >> >> mode_t st_mode; > >> >> nlink_t st_nlink; > >> >> uid_t st_uid; > >> >> gid_t st_gid; > >> >> unsigned long st_rdev; > >> >> unsigned long __st_pad1[3]; > >> >> long long st_size; > >> >> time_t st_atime; > >> >> unsigned long st_atime_nsec; > >> >> time_t st_mtime; > >> >> unsigned long st_mtime_nsec; > >> >> time_t st_ctime; > >> >> unsigned long st_ctime_nsec; > >> >> unsigned long st_blksize; > >> >> unsigned long __st_pad2; > >> >> long long st_blocks; > >> >> }; > >> >> > >> >> It does appear that the syscalls for the two ABIs differ in this... > >> > > >> > This structure is identical to the one in musl except that it has > >> > 32-bit dev_t plus padding in place of 64-bit dev_t, and the musl > >> > version has reserved space at the end. Can you check whether the dev_t > >> > issue is actually a problem (it might be, based on endianness, and if > >> > so I think it would require ugly fixups in userspace)? > >> > >> Ah no, my mistake, you are right, the padding seems correct and I was > >> getting confused as usual by dev_t. However the 64 bit dev_t is a > >> problem on bigendian mips. > >> > >> (Whats the reason for Musl using 64 bit dev_t? glibc compatibility?) > > > > And room for expansion, and consistency of the type between archs. > > There's no justification for dev_t or similar types to be > > arch-specific. > > But isnt the kernel dev_t 32 bit for all archs? Yes and no. They have adjacent padding reserved to make it up to 128-bit, despite the fact that intmax_t is 64-bit everywhere and thus 128-bit types can't really be used. I suspect on big-endian the padding is at the other side to allow for this already, but it might be misaligned with respect to the 64/128 bit size in musl at present. Rich