diff options
| -rw-r--r-- | NEWS | 5 | ||||
| -rw-r--r-- | doc/coreutils.texi | 14 | ||||
| -rw-r--r-- | init.cfg | 4 | ||||
| -rw-r--r-- | src/tail.c | 21 | ||||
| -rw-r--r-- | tests/local.mk | 1 | ||||
| -rw-r--r-- | tests/tail-2/retry.sh | 94 |
6 files changed, 129 insertions, 10 deletions
@@ -13,6 +13,11 @@ GNU coreutils NEWS -*- outline -*- the relative link on the dereferenced path of an existing link. [This bug was introduced when --relative was added in coreutils-8.16.] + tail --retry -f now waits for the files specified to appear. Before, tail + would immediately exit when such a file is inaccessible during the initial + open. + [This bug was introduced when inotify support was added in coreutils-7.5] + ** New features join accepts a new option: --zero-terminated (-z). As with the sort,uniq diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 92917f17f..f6f2eb4f2 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -3155,9 +3155,17 @@ will keep trying until it becomes accessible again. @item --retry @opindex --retry -This option is useful mainly when following by name (i.e., with -@option{--follow=name}). -Without this option, when tail encounters a file that doesn't +Indefinitely try to open the specified file. +This option is useful mainly when following (and otherwise issues a warning). + +When following by file descriptor (i.e., with @option{--follow=descriptor}), +this option only affects the initial open of the file, as after a successful +open, @command{tail} will start following the file descriptor. + +When following by name (i.e., with @option{--follow=name}), @command{tail} +infinitely retries to re-open the given files until killed. + +Without this option, when @command{tail} encounters a file that doesn't exist or is otherwise inaccessible, it reports that fact and never checks it again. @@ -556,11 +556,13 @@ working_umask_or_skip_() # Note ensure you do _not_ quote the parameter to GNU sleep in # your function, as it may contain separate values that sleep # needs to accumulate. +# Further function arguments will be forwarded to the test function. retry_delay_() { local test_func=$1 local init_delay=$2 local max_n_tries=$3 + shift 3 || return 1 local attempt=1 local num_sleeps=$attempt @@ -568,7 +570,7 @@ retry_delay_() while test $attempt -le $max_n_tries; do local delay=$($AWK -v n=$num_sleeps -v s="$init_delay" \ 'BEGIN { print s * n }') - "$test_func" "$delay" && { time_fail=0; break; } || time_fail=1 + "$test_func" "$delay" "$@" && { time_fail=0; break; } || time_fail=1 attempt=$(expr $attempt + 1) num_sleeps=$(expr $num_sleeps '*' 2) done diff --git a/src/tail.c b/src/tail.c index cdaecddc4..373575705 100644 --- a/src/tail.c +++ b/src/tail.c @@ -294,9 +294,7 @@ With no FILE, or when FILE is -, read standard input.\n\ fputs (_("\ --pid=PID with -f, terminate after process ID, PID dies\n\ -q, --quiet, --silent never output headers giving file names\n\ - --retry keep trying to open a file even when it is or\n\ - becomes inaccessible; useful when following by\n\ - name, i.e., with --follow=name\n\ + --retry keep trying to open a file if it is inaccessible\n\ "), stdout); fputs (_("\ -s, --sleep-interval=N with -f, sleep for approximately N seconds\n\ @@ -2030,8 +2028,14 @@ parse_options (int argc, char **argv, } } - if (reopen_inaccessible_files && follow_mode != Follow_name) - error (0, 0, _("warning: --retry is useful mainly when following by name")); + if (reopen_inaccessible_files) + { + if (!forever) + error (0, 0, _("warning: --retry ignored; --retry is useful" + " only when following")); + else if (follow_mode == Follow_descriptor) + error (0, 0, _("warning: --retry only effective for the initial open")); + } if (pid && !forever) error (0, 0, @@ -2182,6 +2186,10 @@ main (int argc, char **argv) in this case because it would miss any updates to the file that were not initiated from the local system. + ok is false when one of the files specified could not be opened for + reading. In this case and when following by descriptor, + tail_forever_inotify() cannot be used (in its current implementation). + FIXME: inotify doesn't give any notification when a new (remote) file or directory is mounted on top a watched file. When follow_mode == Follow_name we would ideally like to detect that. @@ -2193,7 +2201,8 @@ main (int argc, char **argv) is recreated, then we don't recheck any new file when follow_mode == Follow_name */ if (!disable_inotify && (tailable_stdin (F, n_files) - || any_remote_file (F, n_files))) + || any_remote_file (F, n_files) + || (!ok && follow_mode == Follow_descriptor))) disable_inotify = true; if (!disable_inotify) diff --git a/tests/local.mk b/tests/local.mk index 0b019d951..f47da8d3a 100644 --- a/tests/local.mk +++ b/tests/local.mk @@ -390,6 +390,7 @@ all_tests = \ tests/misc/uniq-perf.sh \ tests/misc/xattr.sh \ tests/tail-2/wait.sh \ + tests/tail-2/retry.sh \ tests/chmod/c-option.sh \ tests/chmod/equal-x.sh \ tests/chmod/equals.sh \ diff --git a/tests/tail-2/retry.sh b/tests/tail-2/retry.sh new file mode 100644 index 000000000..71d101556 --- /dev/null +++ b/tests/tail-2/retry.sh @@ -0,0 +1,94 @@ +#!/bin/sh +# Exercise tail's behavior regarding missing files with/without --retry. + +# Copyright (C) 2013 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=.}/tests/init.sh"; path_prepend_ ./src +print_ver_ tail + +# Function to check the expected line count in 'out'. +# Called via retry_delay_(). Sleep some time - see retry_delay_() - if the +# line count is still smaller than expected. +wait4lines_ () +{ + local delay=$1 + local elc=$2 # Expected line count. + [ $( wc -l < out ) -ge $elc ] || { sleep $delay; return 1; } +} + +# === Test: +# Retry without --follow results in a warning. +touch file +tail --retry file > out 2>&1 || fail=1 +[ $( wc -l < out ) = 1 ] || fail=1 +grep -F 'tail: warning: --retry ignored' out || fail=1 + +# === Test: +# The same with a missing file: expect error message and exit 1. +tail --retry missing > out 2>&1 && fail=1 +[ $( wc -l < out ) = 2 ] || fail=1 +grep -F 'tail: warning: --retry ignored' out || fail=1 + +# === Test: +# Ensure that "tail --retry --follow=name" waits for the file to appear. +timeout 10 tail -s.1 --follow=name --retry missing >out 2>&1 & pid=$! +retry_delay_ wait4lines_ .1 6 1 || fail=1 # Wait for "cannot open" error. +echo "X" > missing || fail=1 # Write "X" into 'missing'. +retry_delay_ wait4lines_ .1 6 3 || fail=1 # Wait for the expected output. +kill $pid +wait $pid +# Expect 3 lines in the output file. +[ $( wc -l < out ) = 3 ] || { fail=1; cat out; } +grep -F 'cannot open' out || { fail=1; cat out; } +grep -F 'has become accessible' out || { fail=1; cat out; } +grep '^X$' out || { fail=1; cat out; } +rm -f missing out || fail=1 + +# === Test: +# Ensure that "tail --retry --follow=descriptor" waits for the file to appear. +# tail-8.21 failed at this (since the implementation of the inotify support). +timeout 10 tail -s.1 --follow=descriptor --retry missing >out 2>&1 & pid=$! +retry_delay_ wait4lines_ .1 6 2 || fail=1 # Wait for "cannot open" error. +echo "X" > missing || fail=1 # Write "X" into 'missing'. +retry_delay_ wait4lines_ .1 6 4 || fail=1 # Wait for the expected output. +kill $pid +wait $pid +# Expect 4 lines in the output file. +[ $( wc -l < out ) = 4 ] || { fail=1; cat out; } +grep -F 'retry only effective for the initial open' out \ + || { fail=1; cat out; } +grep -F 'cannot open' out || { fail=1; cat out; } +grep -F 'has appeared' out || { fail=1; cat out; } +grep '^X$' out || { fail=1; cat out; } +rm -f missing out || fail=1 + +# === Test: +# Ensure that --follow=descriptor (without --retry) does *not wait* for the +# file to appear. Expect 2 lines in the output file ("cannot open" + +# "no files remaining") and exit status 1. +tail --follow=descriptor missing >out 2>&1 && fail=1 +[ $( wc -l < out ) = 2 ] || { fail=1; cat out; } +grep -F 'cannot open' out || { fail=1; cat out; } +grep -F 'no files remaining' out || { fail=1; cat out; } + +# === Test: +# Likewise for --follow=name (without --retry). +tail --follow=name missing >out 2>&1 && fail=1 +[ $( wc -l < out ) = 2 ] || { fail=1; cat out; } +grep -F 'cannot open' out || { fail=1; cat out; } +grep -F 'no files remaining' out || { fail=1; cat out; } + +Exit $fail |