From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.17.10]) by sourceware.org (Postfix) with ESMTPS id B0C64385781A for ; Mon, 25 Jan 2021 18:57:32 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org B0C64385781A Received: from calimero.vinschen.de ([24.134.7.25]) by mrelayeu.kundenserver.de (mreue109 [212.227.15.183]) with ESMTPSA (Nemesis) id 1MLR5h-1lKxVw1ohP-00IVW1 for ; Mon, 25 Jan 2021 19:57:31 +0100 Received: by calimero.vinschen.de (Postfix, from userid 500) id 48F8EA80D4E; Mon, 25 Jan 2021 19:57:30 +0100 (CET) Date: Mon, 25 Jan 2021 19:57:30 +0100 From: Corinna Vinschen To: cygwin-patches@cygwin.com Subject: Re: [PATCH] Cygwin: chown: make sure ctime gets updated when necessary Message-ID: <20210125185730.GF4393@calimero.vinschen.de> Reply-To: cygwin-patches@cygwin.com Mail-Followup-To: cygwin-patches@cygwin.com References: <20210125172455.64675-1-kbrown@cornell.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210125172455.64675-1-kbrown@cornell.edu> X-Provags-ID: V03:K1:Jrf3NvCMRiX3VowIlXDVEruKNQfXOSgX+FgaqJXz0cGQpnb/nqV hnsa6i6Q14LRlbdzLqRFvyWsKCFJB3HJbZzpPLyaPPa/QsGGGB8552KdOkr7u7KIa5Afy2D cPlC+w14eeWSjSnFyGgn0OtGzcbuc7YcIdmDzAI3bhCx6d7Rq7WEfJ/p3VkKgssyw07yMBk j/j8GnZ9Tp0MMmBTJqGxg== X-UI-Out-Filterresults: notjunk:1;V03:K0:k7LLkpAFSMA=:b1eeOm4SOtcjIEli+iMZ9R 1qZ5qA1hx7CBvR8/XbxE9xCsaG8aYxfFgnV5M/1gYSls/J2Pc3wng8QtobpOeVhIuc4uepWVo nRTu3TbDEQT4r40fer0S7ZTKbdYa/+yA+tVRQX++n6uTkSM29dEIzRMg5xxC6lDH0zRGeLgZ3 UfHAHM7bCJVztpg7Kai57HMN/ecYdS1bQkDF6cJQ7uD5CMX9LUF3RZrDuXX0e7fb1sROHecJF kZof3s5a4HMfC0YqhBLMnhkTjraSaLBemySZxLzZK6lV09Io914ZbBkaBvI1qChtoDvRZJ40+ lgHlymSffSIyh7CDV1EhRS89Z9CLzYcDKJA+fI5szwmn1awpS0ckpv/1IaZnuWCuMP3h44IfH 2+T3NBeaSrCweE9sFSh1E7tVLdX3ohrJK9DpnRDZXCblo9JITtnwe/hDErFTkuEQwoIUP2BRK bNhDlfCfKw== X-Spam-Status: No, score=-107.1 required=5.0 tests=BAYES_00, GIT_PATCH_0, GOOD_FROM_CORINNA_CYGWIN, KAM_DMARC_NONE, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NEUTRAL, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: cygwin-patches@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Cygwin core component patch submission and discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Jan 2021 18:57:34 -0000 On Jan 25 12:24, Ken Brown via Cygwin-patches wrote: > Following POSIX, ensure that ctime is updated if chown succeeds, > unless the new owner is specified as (uid_t)-1 and the new group is > specified as (gid_t)-1. Previously, ctime was unchanged whenever the > owner and group were both unchanged. > > Aside from POSIX compliance, this fix makes gnulib report that chown > works on Cygwin. This improves the efficiency of packages like GNU > tar that use gnulib's chown module. Previously such packages would > use a gnulib replacement for chown on Cygwin. > --- > winsup/cygwin/fhandler_disk_file.cc | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/winsup/cygwin/fhandler_disk_file.cc b/winsup/cygwin/fhandler_disk_file.cc > index 07f9c513a..72d259579 100644 > --- a/winsup/cygwin/fhandler_disk_file.cc > +++ b/winsup/cygwin/fhandler_disk_file.cc > @@ -863,6 +863,7 @@ fhandler_disk_file::fchown (uid_t uid, gid_t gid) > tmp_pathbuf tp; > aclent_t *aclp; > int nentries; > + bool noop = true; > > if (!pc.has_acls ()) > { > @@ -887,11 +888,18 @@ fhandler_disk_file::fchown (uid_t uid, gid_t gid) > aclp, MAX_ACL_ENTRIES)) < 0) > goto out; > > + /* According to POSIX, chown can be a no-op if uid is (uid_t)-1 and > + gid is (gid_t)-1. Otherwise, even if uid and gid are unchanged, > + we must ensure that ctime is updated. */ > if (uid == ILLEGAL_UID) > uid = old_uid; > + else > + noop = false; > if (gid == ILLEGAL_GID) > gid = old_gid; > - if (uid == old_uid && gid == old_gid) Basically ok, but why not just if (uid == ILLEGAL_UID && gid == ILLEGAL_GID) instead of the noop var? Corinna