Add timeout for fifo in integration tests

If the client or server crashes during the integration test run
the next write to its fifo file will be blocking and get stuck forever.

This is especially annoying for github actions because they just run 10
hours and then get terminated by github without ever reaching the end
of the integration test script that then prints the details about the
crash.

scripts/integration_test.sh

@@ -50,7 +50,9 @@ function kill_all() {
 
 	if [[ ! -f fail_server.txt ]]; then
 		echo "[*] Shutting down server"
-		echo "shutdown" > server.fifo
+		if ! timeout 3 sh -c "echo shutdown > server.fifo"; then
+			echo "[-] shutdown server timed out"
+		fi
 	fi
 	sleep 1
 
@@ -58,7 +60,9 @@ function kill_all() {
 	for ((i = 1; i < 3; i++)); do
 		if [[ ! -f fail_client$i.txt ]]; then
 			echo "[*] Shutting down client$i"
-			echo "quit" > "client$i.fifo"
+			if ! timeout 3 sh -c "echo quit > \"client$i.fifo\""; then
+				echo "[-] shutdown client $i timed out"
+			fi
 		fi
 	done
 	sleep 1
@@ -77,6 +81,28 @@ function fail() {
 	echo "[-] $1 exited with code $2"
 }
 
+function fifo() {
+	local cmd="$1"
+	local fifo_file="$2"
+	if [ -f fail_fifo_timeout.txt ]; then
+		echo "[fifo] skipping because of timeout cmd: $cmd"
+		return
+	fi
+	if [ "$arg_verbose" == "1" ]; then
+		echo "[fifo] $cmd >> $fifo_file"
+	fi
+	if printf '%s' "$cmd" | grep -q '[`'"'"']'; then
+		echo "[-] fifo commands can not contain backticks or single quotes"
+		echo "[-] invalid fifo command: $cmd"
+		return
+	fi
+	if ! timeout 3 sh -c "printf '%s\n' '$cmd' >> \"$fifo_file\""; then
+		fifo_error="[-] fifo command timeout: $cmd >> $fifo_file"
+		printf '%s\n' "$fifo_error"
+		printf '%s\n' "$fifo_error" >> fail_fifo_timeout.txt
+	fi
+}
+
 # Get unused port from the system by binding to port 0 and immediately closing the socket again
 port=$(python3 -c 'import socket; s=socket.socket(); s.bind(("", 0)); print(s.getsockname()[1]); s.close()')
 
@@ -190,8 +216,8 @@ $tool ../DDNet \
 wait_for_launch client1.fifo 3
 
 echo "[*] Start demo recording"
-echo "record server" > server.fifo
-echo "record client1" > client1.fifo
+fifo "record server" server.fifo
+fifo "record client1" client1.fifo
 
 echo "[*] Launch client 2"
 $tool ../DDNet \
@@ -207,10 +233,11 @@ wait_for_launch client2.fifo 5
 sleep 15
 
 echo "[*] Test chat and chat commands"
-echo "say hello world" > client1.fifo
-echo "rcon_auth rcon" > client1.fifo
+fifo "say hello world" client1.fifo
+fifo "rcon_auth rcon" client1.fifo
 sleep 1
-tr -d '\n' > client1.fifo << EOF
+fifo "$(
+	tr -d '\n' << EOF
 say "/mc
 ;top5
 ;rank
@@ -228,10 +255,13 @@ say "/mc
 ;cmdlist
 ;saytime"
 EOF
+)" client1.fifo
+
 sleep 10
 
 echo "[*] Test rcon commands"
-tr -d '\n' > client1.fifo << EOF
+fifo "$(
+	tr -d '\n' << EOF
 rcon say hello from admin;
 rcon broadcast test;
 rcon status;
@@ -239,15 +269,16 @@ rcon echo test;
 muteid 1 900 spam;
 unban_all;
 EOF
+)" client1.fifo
 sleep 5
 
 echo "[*] Stop demo recording"
-echo "stoprecord" > server.fifo
-echo "stoprecord" > client1.fifo
+fifo "stoprecord" server.fifo
+fifo "stoprecord" client1.fifo
 sleep 1
 
 echo "[*] Test map change"
-echo "rcon sv_map Tutorial" > client1.fifo
+fifo "rcon sv_map Tutorial" client1.fifo
 if [ "$arg_valgrind_memcheck" == "1" ]; then
 	sleep 60
 else
@@ -255,8 +286,8 @@ else
 fi
 
 echo "[*] Play demos"
-echo "play demos/server.demo" > client1.fifo
-echo "play demos/client1.demo" > client2.fifo
+fifo "play demos/server.demo" client1.fifo
+fifo "play demos/client1.demo" client2.fifo
 if [ "$arg_valgrind_memcheck" == "1" ]; then
 	sleep 40
 else