From owner-freebsd-bugs@FreeBSD.ORG Sat Sep 28 18:50:02 2013 Return-Path: Delivered-To: freebsd-bugs@smarthost.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 6276E78E for ; Sat, 28 Sep 2013 18:50:02 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:1900:2254:206c::16:87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 4D4282C2B for ; Sat, 28 Sep 2013 18:50:02 +0000 (UTC) Received: from freefall.freebsd.org (localhost [127.0.0.1]) by freefall.freebsd.org (8.14.7/8.14.7) with ESMTP id r8SIo1ka069515 for ; Sat, 28 Sep 2013 18:50:01 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.7/8.14.7/Submit) id r8SIo1pV069514; Sat, 28 Sep 2013 18:50:01 GMT (envelope-from gnats) Date: Sat, 28 Sep 2013 18:50:01 GMT Message-Id: <201309281850.r8SIo1pV069514@freefall.freebsd.org> To: freebsd-bugs@FreeBSD.org Cc: From: Jilles Tjoelker Subject: Re: bin/182098: [patch] Change kldxref fts_open ordering so it produces a consistent linker.hints between machines of the same architecture. X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: Jilles Tjoelker List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 28 Sep 2013 18:50:02 -0000 The following reply was made to PR bin/182098; it has been noted by GNATS. From: Jilles Tjoelker To: Derek Schrock Cc: bug-followup@FreeBSD.org Subject: Re: bin/182098: [patch] Change kldxref fts_open ordering so it produces a consistent linker.hints between machines of the same architecture. Date: Sat, 28 Sep 2013 20:39:53 +0200 On Tue, Sep 24, 2013 at 09:32:42PM -0400, Derek Schrock wrote: > On Mon, Sep 16, 2013 at 12:39:58AM +0200, Jilles Tjoelker wrote: > > In the interest of reproducible builds, your patch seems a good idea. It > > seems unattractive to run kldxref /boot/kernel on every machine. > > > > The implementation of compare() seems unnecessarily complex though. In > > find -s, the fts_names are simply passed to strcoll() (here, strcmp() > > would be better). The trickery with the length may cause inconsistent > > results if one filename is a prefix of another (rare). > Fair enough after reading more of the fts(3) man fts_name is always > null terminated. > > This change may also expose a latent bug with kldxref -R: it does not > > work properly if a directory contains both files that need a mention in > > a hints file and subdirectories, and at least one such file appears > > after a subdirectory. Because your change alters the traversal order, it > > might break a use of kldxref -R that previously happened to work. You > > can make it work reliably by sorting FTS_D entries after other entries. > Yep, after some additional testing with the patched kldxref it > produced different linker.hints files. Hmm, that is unexpected. The sorting happens on entries of each directory, and find -s does the same. > The new patch uses fts_parent's fts_name (the directory's name). > First compare the parent's name, if the same compare the passed > FTSENTs. The comparison on the parent's name seems redundant due to the way fts(3) does the sorting. I tried my idea using FTS_D. Here is a script to test kldxref on this: #!/bin/sh kldxref=${1:-kldxref} kldxrefpath=$(command -v "$kldxref" 2>/dev/null) || { printf "%s not found\n" "$kldxref" exit } printf "Testing %s\n" "$kldxrefpath" tmpdir=$(mktemp -d -t kldxreftest) || exit cd "$tmpdir" || exit cp /boot/kernel/if_re.ko . || exit mkdir subdir1 || exit cp /boot/kernel/if_faith.ko . || exit cp /boot/kernel/zlib.ko . || exit cp /boot/kernel/unionfs.ko subdir1 || exit printf "Directory structure created in %s\n" "$tmpdir" "$kldxref" -R "$tmpdir" mainstrings=$(strings linker.hints) subdir1strings=$(strings subdir1/linker.hints) bad= for m in if_re.ko if_faith.ko zlib.ko; do case $mainstrings in *"$m"*) ;; *) printf "%s is missing from main\n" "$m"; bad=1 ;; esac case $subdir1strings in *"$m"*) printf "subdir1 wrongly has %s\n" "$m"; bad=1 ;; esac done for m in unionfs.ko; do case $subdir1strings in *"$m"*) ;; *) printf "%s is missing from subdir1\n" "$m"; bad=1 ;; esac case $mainstrings in *"$m"*) printf "main wrongly has %s\n" "$m"; bad=1 ;; esac done if [ -z "$bad" ]; then printf "%s appears to be working correctly\n" "$kldxrefpath" fi My suggested patch: Index: usr.sbin/kldxref/kldxref.c =================================================================== --- usr.sbin/kldxref/kldxref.c (revision 255570) +++ usr.sbin/kldxref/kldxref.c (working copy) @@ -274,6 +274,16 @@ exit(1); } +int +compare(const FTSENT* const* a, const FTSENT* const* b) +{ + if ((*a)->fts_info == FTS_D && (*b)->fts_info != FTS_D) + return 1; + if ((*a)->fts_info != FTS_D && (*b)->fts_info == FTS_D) + return -1; + return strcmp((*a)->fts_name, (*b)->fts_name); +} + int main(int argc, char *argv[]) { @@ -315,7 +325,7 @@ err(1, "%s", argv[0]); } - ftsp = fts_open(argv, fts_options, 0); + ftsp = fts_open(argv, fts_options, compare); if (ftsp == NULL) exit(1); -- Jilles Tjoelker