Package: coreutils;
Reported by: Jim Meyering <jim <at> meyering.net>
Date: Sun, 24 Apr 2011 21:24:01 UTC
Severity: normal
Done: Jim Meyering <jim <at> meyering.net>
Bug is archived. No further changes may be made.
Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):
From: Jim Meyering <jim <at> meyering.net> To: Tim Underwood <timunderwood <at> gmail.com> Cc: bug-coreutils <at> gnu.org Subject: Re: tail bug - starting in 7.5 "tail --follow=name" behaves like "tail --follow=name --retry" Date: Sun, 24 Apr 2011 23:22:46 +0200
Tim Underwood wrote:
> Going from Ubuntu 10.04 (coreutils 7.4) to Ubuntu 10.10 (coreutils 8.5) I
> noticed that "tail --follow=name" started behaving like "tail --follow=name
> --retry". It looks like the issue started in 7.5 and still exists in 8.9.
>
> To reproduce:
>
> tail --follow=name this_file_does_not_exist
>
> The expected behavior is:
>
> $ ./coreutils-7.4/src/tail --follow=name this_file_does_not_exist
> ./coreutils-7.4/src/tail: cannot open `this_file_does_not_exist' for
> reading: No such file or directory
> ./coreutils-7.4/src/tail: no files remaining
>
> The wrong behavior is:
>
> $ ./coreutils-7.5/src/tail --follow=name this_file_does_not_exist
> ./coreutils-7.5/src/tail: cannot open `this_file_does_not_exist' for
> reading: No such file or directory
> <tail waits forever for this_file_does_not_exist to become available which
> is what --retry is for>
>
> Here's the wrong behavior on 8.9:
>
> $ ./coreutils-8.9/src/tail --follow=name this_file_does_not_exist
> ./coreutils-8.9/src/tail: cannot open `this_file_does_not_exist' for
> reading: No such file or directory
> <waits forever...>
>
> My specific use case is to tail a log file until it gets deleted at which
> point tail should exit allowing my script to continue.
Thanks again.
Here's the fix I expect to use:
From 79a476abb35a69f409e2848019c8ebc24cc687cf Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering <at> redhat.com>
Date: Sun, 24 Apr 2011 23:20:01 +0200
Subject: [PATCH] tail --follow=name no longer implies --retry
* src/tail.c (tail_forever_inotify): Just as without inotify,
tail --follow=name now terminates when the last tailed-by-name file
is unlinked or moved aside. This bug was introduced on 2009-06-15
via commit ae494d4b, "tail: use inotify if it is available".
Reported by Tim Underwood in
http://thread.gmane.org/gmane.comp.gnu.coreutils.bugs/22286
* NEWS (Bug fixes): Mention this.
* tests/tail-2/follow-name: Test for this.
* tests/Makefile.am (TESTS): Add it.
---
NEWS | 5 +++++
THANKS.in | 1 +
src/tail.c | 10 ++++++++++
tests/Makefile.am | 1 +
tests/tail-2/follow-name | 32 ++++++++++++++++++++++++++++++++
5 files changed, 49 insertions(+), 0 deletions(-)
create mode 100755 tests/tail-2/follow-name
diff --git a/NEWS b/NEWS
index 7bc2ef3..3307e71 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,11 @@ GNU coreutils NEWS -*- outline -*-
* Noteworthy changes in release ?.? (????-??-??) [?]
+** Bug fixes
+
+ tail's --follow=name option no longer implies --retry on systems
+ with inotify support. [bug introduced in coreutils-7.5]
+
** Changes in behavior
cp's extent-based (FIEMAP) copying code is more reliable in the face
diff --git a/THANKS.in b/THANKS.in
index 342a52c..d1ca380 100644
--- a/THANKS.in
+++ b/THANKS.in
@@ -560,6 +560,7 @@ Tim J. Robbins tjr <at> FreeBSD.org
Tim Mooney mooney <at> dogbert.cc.ndsu.NoDak.edu
Tim Ryan Tim_Ryan <at> bnz.co.nz
Tim Smithers mouse <at> dmouse.com.au
+Tim Underwood timunderwood <at> gmail.com
Tim Waugh twaugh <at> redhat
Toby Peterson toby <at> opendarwin.org
Todd A. Jacobs tjacobs <at> codegnome.org
diff --git a/src/tail.c b/src/tail.c
index 88fbd10..e6d8164 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -1432,6 +1432,16 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
struct File_spec *fspec;
struct inotify_event *ev;
+ /* When following by name without --retry, and the last file has
+ been unlinked or renamed-away, diagnose it and return. */
+ if (follow_mode == Follow_name
+ && ! reopen_inaccessible_files
+ && hash_get_n_entries (wd_to_name) == 0)
+ {
+ error (0, 0, _("no files remaining"));
+ return false;
+ }
+
/* When watching a PID, ensure that a read from WD will not block
indefinitely. */
if (pid)
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 685eb52..2f4a561 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -489,6 +489,7 @@ TESTS = \
tail-2/assert-2 \
tail-2/big-4gb \
tail-2/flush-initial \
+ tail-2/follow-name \
tail-2/follow-stdin \
tail-2/pipe-f \
tail-2/pipe-f2 \
diff --git a/tests/tail-2/follow-name b/tests/tail-2/follow-name
new file mode 100755
index 0000000..ef9434a
--- /dev/null
+++ b/tests/tail-2/follow-name
@@ -0,0 +1,32 @@
+#!/bin/sh
+# ensure that --follow=name does not imply --retry
+
+# Copyright (C) 2011 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/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+print_ver_ tail
+
+cat <<\EOF > exp || framework_failure_
+tail: cannot open `no-such' for reading: No such file or directory
+tail: no files remaining
+EOF
+
+timeout 10 tail --follow=name no-such > out 2> err
+test $? = 1 || fail=1
+
+compare err exp || fail=1
+
+Exit $fail
--
1.7.5.rc3.316.gd1ff9
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.