Here's the full patch: >From b65cdea4dc1ec03be8bbc91cea261860373c8554 Mon Sep 17 00:00:00 2001 From: Jim Meyering <meyer...@redhat.com> Date: Mon, 7 Sep 2009 08:37:08 +0200 Subject: [PATCH] tail -f: handle "-"/stdin once again
* src/tail.c (main) [HAVE_INOTIFY]: When stdin (i.e., "-", or no args, but not /dev/stdin) is specified on the command line, don't use inotify. Reported by Bill Brelsford in <http://bugs.debian.org/545422>. * tests/tail-2/follow-stdin: New file. Test for this. * tests/Makefile.am (TESTS): Add the test. * NEWS (Bug fixes): Mention it. This bug was introduced in coreutils-7.5 via commit ae494d4b, 2009-06-02, "tail: use inotify if it is available". --- NEWS | 9 +++++++++ THANKS | 1 + src/tail.c | 14 +++++++++++++- tests/Makefile.am | 1 + tests/tail-2/follow-stdin | 41 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 65 insertions(+), 1 deletions(-) create mode 100755 tests/tail-2/follow-stdin diff --git a/NEWS b/NEWS index b02d2da..5c7fb82 100644 --- a/NEWS +++ b/NEWS @@ -31,6 +31,15 @@ GNU coreutils NEWS -*- outline -*- Before, this would print nothing and wait: stdbuf -o 4K tail -f /etc/passwd Note that this bug affects tail -f only when its standard output is buffered, which is relatively unusual. + [bug introduced in coreutils-7.5] + + tail -f once again works with standard input. inotify-enabled tail -f + would fail when operating on a nameless stdin. I.e., tail -f < /etc/passwd + would say "tail: cannot watch `-': No such file or directory", yet the + relatively baroque tail -f /dev/stdin < /etc/passwd would work. Now, the + offending usage causes tail to revert to its conventional sleep-based + (i.e., not inotify-based) implementation. + [bug introduced in coreutils-7.5] ** New features diff --git a/THANKS b/THANKS index 0c5bb40..2410866 100644 --- a/THANKS +++ b/THANKS @@ -78,6 +78,7 @@ Bernhard Rosenkraenzer b...@redhat.de Bernhard Voelker bernhard.voel...@siemens-enterprise.com Bert Deknuydt bert.deknu...@esat.kuleuven.ac.be Bert Wesarg bert.wes...@googlemail.com +Bill Brelsford w...@k2di.net Bill Peters pet...@gaffel.as.arizona.edu Bjorn Helgaas helg...@rsn.hp.com Bob McCracken kero...@ravenet.com diff --git a/src/tail.c b/src/tail.c index e3b9529..c53df9e 100644 --- a/src/tail.c +++ b/src/tail.c @@ -1982,7 +1982,19 @@ main (int argc, char **argv) if (forever) { #if HAVE_INOTIFY - if (!disable_inotify) + /* If the user specifies stdin via a command line argument of "-", + or implicitly by providing no arguments, we won't use inotify. + Technically, on systems with a working /dev/stdin, we *could*, + but would it be worth it? Verifying that it's a real device + and hooked up to stdin is not trivial, while reverting to + non-inotify-based tail_forever is easy and portable. */ + bool stdin_cmdline_arg = false; + + for (i = 0; i < n_files; i++) + if (STREQ (file[i], "-")) + stdin_cmdline_arg = true; + + if (!disable_inotify && !stdin_cmdline_arg) { int wd = inotify_init (); if (wd < 0) diff --git a/tests/Makefile.am b/tests/Makefile.am index d83d41b..6b3c2b1 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -428,6 +428,7 @@ TESTS = \ tail-2/assert-2 \ tail-2/big-4gb \ tail-2/flush-initial \ + tail-2/follow-stdin \ tail-2/proc-ksyms \ tail-2/start-middle \ touch/dangling-symlink \ diff --git a/tests/tail-2/follow-stdin b/tests/tail-2/follow-stdin new file mode 100755 index 0000000..46e7ce8 --- /dev/null +++ b/tests/tail-2/follow-stdin @@ -0,0 +1,41 @@ +#!/bin/sh +# tail -f - would fail with the initial inotify implementation + +# Copyright (C) 2009 Free Software Foundation, Inc. + +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. + +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +if test "$VERBOSE" = yes; then + set -x + tail --version +fi + +. $srcdir/test-lib.sh + +echo line > exp || framework_failure +echo line > in || framework_failure + +fail=0 +timeout 1 tail -f < in > out 2> err + +# tail from coreutils-7.5 would fail +test $? = 124 || fail=1 + +# Ensure there was no error output. +test -s err && fail=1 + +# Ensure there was +compare out exp || fail=1 + +Exit $fail -- 1.6.4.2.419.gab238
