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[PATCH] tail: display file headers correctly with inotify
From: |
Pádraig Brady |
Subject: |
[PATCH] tail: display file headers correctly with inotify |
Date: |
Tue, 9 Jun 2015 01:54:21 +0100 |
* src/tail.c (tail_forever_inotify): Use the fspec pointer to
distinguish previously output files, rather than a descriptor
from the inotify event. That event descriptor was that of
the parent directory when files were created or renamed etc.
(check_fspec): Adjust for the new comparison. Also show the
header when the file is truncated, since we show data
in this case also.
* tests/tail-2/F-headers.sh: A new test case.
* tests/local.mk: Reference the new test.
* NEWS: Mention the bug fix.
---
NEWS | 4 ++++
src/tail.c | 22 ++++++++++--------
tests/local.mk | 1 +
tests/tail-2/F-headers.sh | 59 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 76 insertions(+), 10 deletions(-)
create mode 100755 tests/tail-2/F-headers.sh
diff --git a/NEWS b/NEWS
index c2576c5..4c0f6e4 100644
--- a/NEWS
+++ b/NEWS
@@ -56,6 +56,10 @@ GNU coreutils NEWS -*-
outline -*-
tail --follow consistently outputs all data for a truncated file.
[bug introduced in the beginning]
+ tail --follow=name correctly outputs headers for multiple files
+ when those files are being created or renamed.
+ [bug introduced in coreutils-7.5]
+
** 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 c9736ca..047d93c 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -1046,7 +1046,9 @@ recheck (struct File_spec *f, bool blocking)
{
/* This happens when one iteration finds the file missing,
then the preceding <dev,inode> pair is reused as the
- file is recreated. */
+ file is recreated. XXX: This means the file is redisplayed
+ in --follow=name mode if renamed away from and back to
+ a monitored name. */
new_file = true;
}
else
@@ -1321,7 +1323,7 @@ wd_comparator (const void *e1, const void *e2)
/* Output (new) data for FSPEC->fd. */
static void
-check_fspec (struct File_spec *fspec, int wd, int *prev_wd)
+check_fspec (struct File_spec *fspec, struct File_spec **prev_fspec)
{
struct stat stats;
char const *name;
@@ -1347,7 +1349,6 @@ check_fspec (struct File_spec *fspec, int wd, int
*prev_wd)
if (S_ISREG (fspec->mode) && stats.st_size < fspec->size)
{
error (0, 0, _("%s: file truncated"), name);
- *prev_wd = wd;
xlseek (fspec->fd, 0, SEEK_SET, name);
fspec->size = 0;
}
@@ -1355,11 +1356,11 @@ check_fspec (struct File_spec *fspec, int wd, int
*prev_wd)
&& timespec_cmp (fspec->mtime, get_stat_mtime (&stats)) == 0)
return;
- if (wd != *prev_wd)
+ if (fspec != *prev_fspec)
{
if (print_headers)
write_header (name);
- *prev_wd = wd;
+ *prev_fspec = fspec;
}
uintmax_t bytes_read = dump_remainder (name, fspec->fd, COPY_TO_EOF);
@@ -1391,7 +1392,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t
n_files,
bool found_unwatchable_dir = false;
bool no_inotify_resources = false;
bool writer_is_dead = false;
- int prev_wd;
+ struct File_spec *prev_fspec;
size_t evlen = 0;
char *evbuf;
size_t evbuf_off = 0;
@@ -1492,7 +1493,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t
n_files,
if (follow_mode == Follow_descriptor && !found_watchable_file)
return false;
- prev_wd = f[n_files - 1].wd;
+ prev_fspec = &(f[n_files - 1]);
/* Check files again. New files or data can be available since last time we
checked and before they are watched by inotify. */
@@ -1524,7 +1525,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t
n_files,
}
/* check for new data. */
- check_fspec (&f[i], f[i].wd, &prev_wd);
+ check_fspec (&f[i], &prev_fspec);
}
}
@@ -1703,7 +1704,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t
n_files,
continue;
}
- check_fspec (fspec, ev->wd, &prev_wd);
+ check_fspec (fspec, &prev_fspec);
}
}
#endif
@@ -2316,7 +2317,8 @@ main (int argc, char **argv)
FIXME-maybe: inotify has a watch descriptor per inode, and hence with
our current hash implementation will only --follow data for one
- of the names when multiple hardlinked files are specified. */
+ of the names when multiple hardlinked files are specified, or
+ for one name when a name is specified multiple times. */
if (!disable_inotify && (tailable_stdin (F, n_files)
|| any_remote_file (F, n_files)
|| any_symlinks (F, n_files)
diff --git a/tests/local.mk b/tests/local.mk
index bb78796..7b8c91e 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -172,6 +172,7 @@ all_tests = \
tests/tail-2/inotify-hash-abuse2.sh \
tests/tail-2/F-vs-missing.sh \
tests/tail-2/F-vs-rename.sh \
+ tests/tail-2/F-headers.sh \
tests/tail-2/descriptor-vs-rename.sh \
tests/tail-2/inotify-rotate.sh \
tests/tail-2/inotify-rotate-resources.sh \
diff --git a/tests/tail-2/F-headers.sh b/tests/tail-2/F-headers.sh
new file mode 100755
index 0000000..9355c0c
--- /dev/null
+++ b/tests/tail-2/F-headers.sh
@@ -0,0 +1,59 @@
+#!/bin/sh
+# Ensure tail -F distinguishes output with the correct headers
+# Between coreutils 7.5 and 8.23 inclusive, 'tail -F ...' would
+# not output headers for cor created/renamed files in certain cases.
+
+# 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 ||
+ { 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 mode in '' '---disable-inotify'; do
+ rm -f a b out
+
+ tail $mode -F $fastpoll a b > out 2>&1 & pid=$!
+
+ # Wait up to 12.7s for tail to start.
+ tail_re="cannot open 'b'" retry_delay_ check_tail_output .1 7 ||
+ { cat out; fail=1; }
+
+ echo x > a
+ # Wait up to 12.7s for a's header to appear in the output:
+ tail_re='==> a <==' retry_delay_ check_tail_output .1 7 ||
+ { echo "$0: a: unexpected delay?"; cat out; fail=1; }
+
+ echo y > b
+ # Wait up to 12.7s for a's header to appear in the output:
+ tail_re='==> b <==' retry_delay_ check_tail_output .1 7 ||
+ { echo "$0: a: unexpected delay?"; cat out; fail=1; }
+
+ cleanup_
+done
+
+Exit $fail
--
2.4.1
- [PATCH] tail: display file headers correctly with inotify,
Pádraig Brady <=