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, 131 insertions, 0 deletions

diff --git a/tests/tail-2/wait b/tests/tail-2/wait
new file mode 100755
index 000000000..7eee8b159
--- /dev/null
+++ b/tests/tail-2/wait
@@ -0,0 +1,131 @@
+#!/bin/sh
+# Make sure that `tail -f' returns immediately if a file doesn't exist
+# while `tail -F' waits for it to appear.
+
+# 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
+
+. $srcdir/test-lib.sh
+
+require_proc_pid_status_
+
+touch here || framework_failure
+touch k || framework_failure
+(touch not_accessible && chmod 0 not_accessible) || framework_failure
+
+fail=0
+
+tail -s0.1 -f not_here &
+pid=$!
+sleep .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 $pid
+fi
+
+tail -s0.1 -f not_accessible &
+pid=$!
+sleep .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 $pid
+fi
+
+(tail -s0.1 -f here 2>tail.err) &
+pid=$!
+sleep .5
+state=$(get_process_status_ $pid)
+
+if test -n "$state"; then
+  case $state in
+    S*) ;;
+    *)  echo $0: process died 1>&2; fail=1 ;;
+  esac
+  kill $pid
+fi
+
+
+# `tail -F' must wait in any case.
+
+(tail -s0.1 -F here 2>>tail.err) &
+pid=$!
+sleep .5
+state=$(get_process_status_ $pid)
+
+if test -n "$state"; then
+  case $state in
+    S*) ;;
+    *) echo $0: process died 1>&2; fail=1 ;;
+  esac
+  kill $pid
+fi
+
+tail -s0.1 -F not_accessible &
+pid=$!
+sleep .5
+state=$(get_process_status_ $pid)
+
+if test -n "$state"; then
+  case $state in
+    S*) ;;
+    *) echo $0: process died 1>&2; fail=1 ;;
+  esac
+  kill $pid
+fi
+
+tail -s0.1 -F not_here &
+pid=$!
+sleep .5
+state=$(get_process_status_ $pid)
+
+if test -n "$state"; then
+  case $state in
+    S*) ;;
+    *) echo $0: process died 1>&2; fail=1 ;;
+  esac
+  kill $pid
+fi
+
+test -s tail.err && fail=1
+
+tail -s.1 -F k > tail.out &
+pid=$!
+sleep .5
+mv k l
+sleep .5
+touch k
+mv k l
+sleep .5
+echo NO >> l
+sleep .5
+kill $pid
+test -s tail.out && fail=1
+
+Exit $fail