timeout: add --foreground to support interactive commands

Or more accurately, commands not started from the shell prompt,
that are interactive, or need to receive Ctrl-C etc. from the terminal.

* doc/coreutils.texi (timeout invocation): Document --foreground.
* src/timeout.c (main): Set the foreground flag and don't create
a separate group.
(cleanup): Only send a signal directly to the monitored command
when the foreground flag is set.
(usage): Describe --foreground.
* tests/misc/timeout-group: Add a new test.
* tests/Makefile.am: Reference new test.
NEWS: Mention the new option.

Reported by Shay Shimony
Analysis by Alan Curry
Fix suggested by Paul Eggert

1 files changed, 58 insertions, 0 deletions

diff --git a/tests/misc/timeout-group b/tests/misc/timeout-group
new file mode 100755
index 000000000..0c3caa0f0
--- /dev/null
+++ b/tests/misc/timeout-group
@@ -0,0 +1,58 @@
+#!/bin/sh
+# test program group handling
+
+# Copyright (C) 2011 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/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+print_ver_ timeout
+
+# construct a program group hierarchy as follows:
+#  timeout-group - foreground group
+#    group.sh - separate group
+#      timeout.cmd - same group as group.sh
+#
+# We then send a SIGINT to the "separate group"
+# to simulate what happens when a Ctrl-C
+# is sent to the foreground group.
+
+setsid true || skip_ "setsid required to control groups"
+
+cat > timeout.cmd <<\EOF
+#!/bin/sh
+trap 'touch int.received; exit' INT
+touch timeout.running
+sleep 10
+EOF
+chmod a+x timeout.cmd
+
+cat > group.sh <<\EOF
+#!/bin/sh
+timeout --foreground 5 ./timeout.cmd&
+wait
+EOF
+chmod a+x group.sh
+
+# Start above script in its own group.
+# We could use timeout for this, but that assumes an implementation.
+setsid ./group.sh &
+until test -e timeout.running; do sleep .1; done
+# Simulate a Ctrl-C to the group to test timely exit
+# Note dash doesn't support signalling groups (a leading -)
+env kill -INT -- -$!
+wait
+test -e int.received || fail=1
+
+Exit $fail