From owner-freebsd-bugs@freebsd.org Mon Feb 19 08:15:37 2018 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id AD48FF0CBC2 for ; Mon, 19 Feb 2018 08:15:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 458DA86B02 for ; Mon, 19 Feb 2018 08:15:37 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id 4C3D6107ED for ; Mon, 19 Feb 2018 08:15:36 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w1J8FaTj040678 for ; Mon, 19 Feb 2018 08:15:36 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w1J8FakZ040676 for freebsd-bugs@FreeBSD.org; Mon, 19 Feb 2018 08:15:36 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 222671] tail(1): tail -r fails on certain piped input Date: Mon, 19 Feb 2018 08:15:36 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: 11.1-STABLE X-Bugzilla-Keywords: regression X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: pprocacci@gmail.com X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cc Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Feb 2018 08:15:37 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D222671 pprocacci@gmail.com changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |pprocacci@gmail.com --- Comment #2 from pprocacci@gmail.com --- The problem is in usr.bin/tail/reverse.c line 258. The variable `start` is only true when the pointer is at the beginning of t= he buffer. *p is never checked to see if it is a newline while `start` is tru= e. This has the effect of the following being written: '\n1\n'. It does appear that the newline is randomly inserted, but this isn't the ca= se. It's essentially writing this: write(1, '2\n', 2); write(1, '\n1\n', 3); Excuse the inline patch (too late in the morning to create an attachement). The patch solves the problem by checking *p when start is true and fixes the problem. --- reverse.c.orig 2018-02-19 03:13:53.835943000 -0500 +++ reverse.c 2018-02-19 03:14:34.665507000 -0500 @@ -255,8 +255,12 @@ if ((*p =3D=3D '\n') || start) { struct bfelem *tr; - if (start && llen) - WR(p, llen + 1); + if (start && llen){ + if(*p =3D=3D '\n') + WR(p + 1, llen); + else + WR(p, llen + 1); + } else if (llen) WR(p + 1, llen); tr =3D TAILQ_NEXT(tl, entries); --=20 You are receiving this mail because: You are the assignee for the bug.=