Client exit test from Ben Maurer.

regress/control-client-exit-stalled.sh

@@ -0,0 +1,77 @@
+#!/bin/sh
+
+# A control client whose terminal has stopped accepting output (for example
+# its ssh connection or terminal emulator died) never drains the output that
+# server_client_check_exit waits on before sending MSG_EXIT, and may then
+# never close its socket either. This must not prevent the server from
+# exiting: after kill-server the server previously stayed alive forever with
+# server_exit set, closing every new connection immediately, so every new
+# client failed with "server exited unexpectedly" until the server was killed
+# by hand. The server now bounds the exit handshake: it discards output it
+# can never deliver and drops the client if it still does not close.
+#
+# The stalled terminal is simulated by a fifo whose read end is held open but
+# never read.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -Ltest"
+$TMUX kill-server 2>/dev/null
+
+DIR=$(mktemp -d)
+FIFO=$DIR/fifo
+SERVER=
+
+mkfifo "$FIFO" || exit 1
+
+cleanup() {
+	[ -n "$SERVER" ] && kill -9 "$SERVER" 2>/dev/null
+	$TMUX kill-server 2>/dev/null
+	exec 8<&- 2>/dev/null
+	rm -rf "$DIR"
+}
+trap cleanup 0 1 15
+
+# A detached session whose pane floods printable output forever.
+$TMUX -f/dev/null new -d -x 80 -y 24 -s rt 'cat /dev/zero | tr "\000" x' || exit 1
+SERVER=$($TMUX display -pt rt '#{pid}')
+
+# Attach a control client with output down the fifo; stdin held open by sleep
+# so it stays attached. The fifo fills and is never read, so a backlog forms
+# in the server that can never be delivered.
+( sleep 60 ) | $TMUX -f/dev/null -C attach -t rt >"$FIFO" 2>&1 &
+exec 8<"$FIFO"
+
+n=0
+while [ $n -lt 50 ]; do
+	$TMUX lsc -F '#{client_name}' 2>/dev/null | grep -q . && break
+	sleep 0.1
+	n=$((n + 1))
+done
+$TMUX lsc -F '#{client_name}' 2>/dev/null | grep -q . ||
+	{ echo "control client did not attach"; exit 1; }
+
+# Let the pane flood fill the fifo so the client's output is stuck.
+sleep 2
+
+# Ask the server to exit. This sets CLIENT_EXIT on the stalled client, whose
+# output can never drain.
+$TMUX kill-server 2>/dev/null
+
+# The server must exit within the exit timeout (10 seconds) plus slack,
+# rather than staying in limbo forever rejecting new clients.
+n=0
+while [ $n -lt 100 ]; do
+	if ! kill -0 "$SERVER" 2>/dev/null; then
+		SERVER=
+		exit 0
+	fi
+	sleep 0.2
+	n=$((n + 1))
+done
+
+echo "server did not exit after kill-server; new clients see:"
+$TMUX ls 2>&1
+exit 1