service: do not let a script timeout take PID 1 with it

A stop: or reload: script written with a timeout killed Finit at
config load:

    service stop:5,/bin/true service.sh -- Boom

parse_script() takes the timeout as a pointer and the caller decides
whether it wants one.  However, both stop: and reload: scripts so far
have no timeout, i.e., NULL.  Guard the branch that reads a leading
number.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/service.c

@@ -1656,7 +1656,8 @@ static void parse_script(svc_t *svc, char *type, char *script, int *tmo, char *b
 			     script, errstr);
 			goto err;
 		}
-		*tmo = (int)(sec * 1000);
+		if (tmo)
+			*tmo = (int)(sec * 1000);
 	} else {
 		path = script;
 		if (tmo)

test/Makefile.am

@@ -33,6 +33,7 @@ EXTRA_DIST		+= bootstrap-crash.sh
 EXTRA_DIST		+= cond-start-task.sh
 EXTRA_DIST		+= conf-format.sh
 EXTRA_DIST		+= conf-template.sh
+EXTRA_DIST		+= script-timeout.sh
 EXTRA_DIST		+= crashing.sh
 EXTRA_DIST		+= dep-chain-reload.sh
 EXTRA_DIST		+= depserv.sh
@@ -79,6 +80,7 @@ TESTS			+= bootstrap-crash.sh
 TESTS			+= cond-start-task.sh
 TESTS			+= conf-format.sh
 TESTS			+= conf-template.sh
+TESTS			+= script-timeout.sh
 TESTS			+= crashing.sh
 TESTS			+= dep-chain-reload.sh
 TESTS			+= depserv.sh

test/script-timeout.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+# A timeout on a stop: or reload: script must not take PID 1 with it.
+# Those two hooks passed a NULL timeout pointer to parse_script(),
+# which wrote through it whenever the script was prefixed with a
+# valid number.  Only a valid number reached the store, so
+# 'stop:abc,/bin/true' was harmless while 'stop:5,/bin/true' was not.
+set -eu
+
+TEST_DIR=$(dirname "$0")
+
+test_teardown()
+{
+    say "Running test teardown."
+    run "rm -f $FINIT_CONF"
+}
+
+# shellcheck source=/dev/null
+. "$TEST_DIR/lib/setup.sh"
+
+# shellcheck disable=SC2154
+assert_alive()
+{
+	assert "Finit survived $1" "$(kill -0 "$finit_pid" 2>/dev/null && echo yes)" = "yes"
+}
+
+for hook in stop reload post pre; do
+	say "Timeout on a $hook: script"
+	run "echo 'service $hook:5,/bin/true service.sh -- Timeout test' > $FINIT_CONF"
+	run "initctl reload" || true
+	assert_alive "$hook:5,/bin/true"
+done
+
+say 'The service still runs afterwards'
+run "echo 'service stop:5,/bin/true service.sh -- Timeout test' > $FINIT_CONF"
+run "initctl reload"
+retry 'assert_num_children 1 service.sh'