tail: use inotify if it is available

* NEWS: Document the new feature.
* m4/jm-macros.m4: Check if inotify is present.
* src/tail.c (tail_forever_inotify): New function.
(main): Use the inotify-based function, if possible.
* tests/Makefile.am: Add new tests for tail.
* tests/test-lib.sh (require_proc_pid_status_, get_process_status_):
New functions.
* tests/tail-2/pid: New file.
* tests/tail-2/wait: New file.
* tests/tail-2/tail-n0f: Refactor code into the test-lib.sh
require_proc_pid_status_ function.

1 files changed, 68 insertions, 0 deletions

diff --git a/tests/tail-2/pid b/tests/tail-2/pid
new file mode 100755
index 000000000..ff2f099ad
--- /dev/null
+++ b/tests/tail-2/pid
@@ -0,0 +1,68 @@
+#!/bin/sh
+# Test the --pid option of tail.
+
+# Copyright (C) 2003, 2006-2009 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
+
+. $srcdir/test-lib.sh
+
+require_proc_pid_status_
+
+touch here || framework_failure
+
+
+fail=0
+
+# Use tail itself to create a background process.
+
+tail -f here &
+bg_pid=$!
+
+tail -s0.1 -f here --pid=$bg_pid &
+
+pid=$!
+
+sleep 0.5
+
+state=$(get_process_status_ $pid)
+
+if test -n "$state"; then
+  case $state in
+    S*) ;;
+    *) echo $0: process dead 1>&2; fail=1 ;;
+  esac
+  kill $pid
+fi
+
+kill $bg_pid
+
+sleep 0.5
+
+state=$(get_process_status_ $pid)
+
+if test -n "$state"; then
+  case $state in
+    S*) echo $0: process still active 1>&2; fail=1 ;;
+    *) ;;
+  esac
+  kill $pid
+fi
+
+Exit $fail