test: ensure testing uses correct mdmon

When testing we want to run mdmon directly, not use
systemctl to get systemd to run it.

So allow an environment variable to make that choice.

Signed-off-by: NeilBrown <neilb@suse.de>

test

@@ -30,6 +30,9 @@ if grep -s 'Personalities : .*multipath' > /dev/null /proc/mdstat ; then
 fi
 INTEGRITY=yes
 
+# make sure to test local mdmon, not system one
+export MDADM_NO_SYSTEMCTL=1
+
 # assume md0, md1, md2 exist in /dev
 md0=/dev/md0 md1=/dev/md1 md2=/dev/md2
 mdp0=/dev/md_d0

util.c

@@ -1711,36 +1711,39 @@ int start_mdmon(char *devnm)
 		pathbuf[0] = '\0';
 
 	/* First try to run systemctl */
-	switch(fork()) {
-	case 0:
-		/* FIXME yuk. CLOSE_EXEC?? */
-		skipped = 0;
-		for (i = 3; skipped < 20; i++)
-			if (close(i) < 0)
-				skipped++;
-			else
-				skipped = 0;
+	if (!check_env("MDADM_NO_SYSTEMCTL"))
+		switch(fork()) {
+		case 0:
+			/* FIXME yuk. CLOSE_EXEC?? */
+			skipped = 0;
+			for (i = 3; skipped < 20; i++)
+				if (close(i) < 0)
+					skipped++;
+				else
+					skipped = 0;
 
-		/* Don't want to see error messages from systemctl.
-		 * If the service doesn't exist, we start mdmon ourselves.
-		 */
-		close(2);
-		open("/dev/null", O_WRONLY);
-		snprintf(pathbuf, sizeof(pathbuf), "mdmon@%s.service",
-			 devnm);
-		status = execl("/usr/bin/systemctl", "systemctl", "start",
-			       pathbuf, NULL);
-		status = execl("/bin/systemctl", "systemctl", "start",
-			       pathbuf, NULL);
-		exit(1);
-	case -1: pr_err("cannot run mdmon. "
-			 "Array remains readonly\n");
-		return -1;
-	default: /* parent - good */
-		pid = wait(&status);
-		if (pid >= 0 && status == 0)
-			return 0;
-	}
+			/* Don't want to see error messages from
+			 * systemctl.  If the service doesn't exist,
+			 * we start mdmon ourselves.
+			 */
+			close(2);
+			open("/dev/null", O_WRONLY);
+			snprintf(pathbuf, sizeof(pathbuf), "mdmon@%s.service",
+				 devnm);
+			status = execl("/usr/bin/systemctl", "systemctl",
+				       "start",
+				       pathbuf, NULL);
+			status = execl("/bin/systemctl", "systemctl", "start",
+				       pathbuf, NULL);
+			exit(1);
+		case -1: pr_err("cannot run mdmon. "
+				"Array remains readonly\n");
+			return -1;
+		default: /* parent - good */
+			pid = wait(&status);
+			if (pid >= 0 && status == 0)
+				return 0;
+		}
 
 	/* That failed, try running mdmon directly */
 	switch(fork()) {