From owner-svn-src-head@freebsd.org Wed Aug 10 18:19:03 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C2D5ABB504A; Wed, 10 Aug 2016 18:19:03 +0000 (UTC) (envelope-from bdrewery@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 93EE31472; Wed, 10 Aug 2016 18:19:03 +0000 (UTC) (envelope-from bdrewery@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u7AIJ2Ba079358; Wed, 10 Aug 2016 18:19:02 GMT (envelope-from bdrewery@FreeBSD.org) Received: (from bdrewery@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u7AIJ2HE079357; Wed, 10 Aug 2016 18:19:02 GMT (envelope-from bdrewery@FreeBSD.org) Message-Id: <201608101819.u7AIJ2HE079357@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: bdrewery set sender to bdrewery@FreeBSD.org using -f From: Bryan Drewery Date: Wed, 10 Aug 2016 18:19:02 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r303929 - head/usr.bin/xinstall X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Aug 2016 18:19:03 -0000 Author: bdrewery Date: Wed Aug 10 18:19:02 2016 New Revision: 303929 URL: https://svnweb.freebsd.org/changeset/base/303929 Log: Fix -S with -b not atomically updating the destination file. With both of these flags, the backup was created via rename(dest, backup) followed by rename(tmp, dest). This left the destination file missing for a moment which contradicts the point of -S. This fixes a race with installworld where PRECIOUSPROG and PRECIOUSLIB files (which use -S for installation) would briefly be missing. In the case of installing rtld with parallel installworld it could render an error due to not having rtld present to run install/cp in another process. Reported by: jhb Reviewed by: jhb MFC after: 1 week Sponsored by: EMC / Isilon Storage Division Differential Revision: https://reviews.freebsd.org/D7451 Modified: head/usr.bin/xinstall/xinstall.c Modified: head/usr.bin/xinstall/xinstall.c ============================================================================== --- head/usr.bin/xinstall/xinstall.c Wed Aug 10 18:18:51 2016 (r303928) +++ head/usr.bin/xinstall/xinstall.c Wed Aug 10 18:19:02 2016 (r303929) @@ -892,11 +892,17 @@ install(const char *from_name, const cha } if (verbose) (void)printf("install: %s -> %s\n", to_name, backup); - if (rename(to_name, backup) < 0) { + if (unlink(backup) < 0 && errno != ENOENT) { serrno = errno; unlink(tempfile); errno = serrno; - err(EX_OSERR, "rename: %s to %s", to_name, + err(EX_OSERR, "unlink: %s", backup); + } + if (link(to_name, backup) < 0) { + serrno = errno; + unlink(tempfile); + errno = serrno; + err(EX_OSERR, "link: %s to %s", to_name, backup); } }