diff options
| -rw-r--r-- | NEWS | 3 | ||||
| -rw-r--r-- | src/tail.c | 30 | ||||
| -rw-r--r-- | tests/local.mk | 1 | ||||
| -rwxr-xr-x | tests/tail-2/truncate.sh | 56 |
4 files changed, 82 insertions, 8 deletions
@@ -49,6 +49,9 @@ GNU coreutils NEWS -*- outline -*- replaced before inotify watches were created. [bug introduced in coreutils-7.5] + tail --follow consistently outputs all data for a truncated file. + [bug introduced in the beginning] + ** New features chroot accepts the new --skip-chdir option to not change the working directory diff --git a/src/tail.c b/src/tail.c index bc1d04a8f..c9736ca5b 100644 --- a/src/tail.c +++ b/src/tail.c @@ -1025,7 +1025,7 @@ recheck (struct File_spec *f, bool blocking) if (f->fd == -1) { error (0, 0, - _("%s has appeared; following end of new file"), + _("%s has appeared; following new file"), quote (pretty_name (f))); } else @@ -1036,7 +1036,7 @@ recheck (struct File_spec *f, bool blocking) /* File has been replaced (e.g., via log rotation) -- tail the new one. */ error (0, 0, - _("%s has been replaced; following end of new file"), + _("%s has been replaced; following new file"), quote (pretty_name (f))); } } @@ -1055,6 +1055,12 @@ recheck (struct File_spec *f, bool blocking) } } + /* FIXME: When a log is rotated, daemons tend to log to the + old file descriptor until the new file is present and + the daemon is sent a signal. Therefore tail may miss entries + being written to the old file. Perhaps we should keep + the older file open and continue to monitor it until + data is written to a new file. */ if (new_file) { /* Start at the beginning of the file. */ @@ -1193,13 +1199,16 @@ tail_forever (struct File_spec *f, size_t n_files, double sleep_interval) /* reset counter */ f[i].n_unchanged_stats = 0; + /* XXX: This is only a heuristic, as the file may have also + been truncated and written to if st_size >= size + (in which case we ignore new data <= size). */ if (S_ISREG (mode) && stats.st_size < f[i].size) { error (0, 0, _("%s: file truncated"), name); - last = i; - xlseek (fd, stats.st_size, SEEK_SET, name); - f[i].size = stats.st_size; - continue; + /* Assume the file was truncated to 0, + and therefore output all "new" data. */ + xlseek (fd, 0, SEEK_SET, name); + f[i].size = 0; } if (i != last) @@ -1330,12 +1339,17 @@ check_fspec (struct File_spec *fspec, int wd, int *prev_wd) return; } + /* XXX: This is only a heuristic, as the file may have also + been truncated and written to if st_size >= size + (in which case we ignore new data <= size). + Though in the inotify case it's more likely we'll get + separate events for truncate() and write(). */ if (S_ISREG (fspec->mode) && stats.st_size < fspec->size) { error (0, 0, _("%s: file truncated"), name); *prev_wd = wd; - xlseek (fspec->fd, stats.st_size, SEEK_SET, name); - fspec->size = stats.st_size; + xlseek (fspec->fd, 0, SEEK_SET, name); + fspec->size = 0; } else if (S_ISREG (fspec->mode) && stats.st_size == fspec->size && timespec_cmp (fspec->mtime, get_stat_mtime (&stats)) == 0) diff --git a/tests/local.mk b/tests/local.mk index 025276332..8d01064bf 100644 --- a/tests/local.mk +++ b/tests/local.mk @@ -408,6 +408,7 @@ all_tests = \ tests/tail-2/retry.sh \ tests/tail-2/symlink.sh \ tests/tail-2/tail-c.sh \ + tests/tail-2/truncate.sh \ tests/chmod/c-option.sh \ tests/chmod/equal-x.sh \ tests/chmod/equals.sh \ diff --git a/tests/tail-2/truncate.sh b/tests/tail-2/truncate.sh new file mode 100755 index 000000000..82720fda0 --- /dev/null +++ b/tests/tail-2/truncate.sh @@ -0,0 +1,56 @@ +#!/bin/sh +# Ensure all logs are output upon file truncation + +# Copyright (C) 2015 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 + +check_tail_output() +{ + local delay="$1" + grep "$tail_re" out > /dev/null || + { sleep $delay; return 1; } +} + +# Terminate any background tail process +cleanup_() { kill $pid 2>/dev/null && wait $pid; } + +# Speedup the non inotify case +fastpoll='-s.1 --max-unchanged-stats=1' + +for follow in '-f' '-F'; do + for mode in '' '---disable-inotify'; do + rm -f out + seq 10 > f || framework_failure_ + + tail $follow $mode $fastpoll f > out 2>&1 & pid=$! + + # Wait up to 12.7s for tail to start + tail_re='^10$' retry_delay_ check_tail_output .1 7 || + { cat out; fail=1; } + + seq 11 15 > f || framework_failure_ + + # Wait up to 12.7s for new data + tail_re='^15$' retry_delay_ check_tail_output .1 7 || + { cat out; fail=1; } + + cleanup_ + done +done + +Exit $fail |