diff --git a/emperor.c b/emperor.c
index a58d1d64..79aac565 100644
--- a/emperor.c
+++ b/emperor.c
@@ -6,6 +6,7 @@ extern struct uwsgi_server uwsgi;
 extern char **environ;
 
 int emperor_queue;
+char *emperor_absolute_dir;
 
 static void royal_death(int signum) {
 	uwsgi_notify("The Emperor is buried.");
@@ -331,6 +332,9 @@ void emperor_add(char *name, time_t born, char *config, uint32_t config_size) {
 
 		if (uwsgi.vassals_start_hook) {
 			uwsgi_log("running vassal start-hook: %s %s\n", uwsgi.vassals_start_hook, n_ui->name);
+			if (setenv("UWSGI_VASSALS_DIR", emperor_absolute_dir, 1)) {
+				uwsgi_error("setenv()");
+			}
 			int start_hook_ret = uwsgi_run_command_and_wait(uwsgi.vassals_start_hook, n_ui->name);
 			uwsgi_log("%s start-hook returned %d\n", n_ui->name, start_hook_ret);
 		}
@@ -434,6 +438,7 @@ reconnect:
 			uwsgi_error("glob()");
 			exit(1);
 		}
+		emperor_absolute_dir = realpath(".", NULL);
 	}
 
 	ui = &ui_base;
diff --git a/utils.c b/utils.c
index 9677e194..3e7827e2 100644
--- a/utils.c
+++ b/utils.c
@@ -2311,10 +2311,9 @@ void uwsgi_sig_pause() {
 	sigsuspend(&mask);
 }
 
-int uwsgi_run_command_and_wait(char *command, ...) {
-
-	va_list ap;
+int uwsgi_run_command_and_wait(char *command, char *arg) {
 
+	char *argv[3];
 	int waitpid_status = 0;
 	pid_t pid = fork();
 	if (pid < 0) {
@@ -2330,11 +2329,13 @@ int uwsgi_run_command_and_wait(char *command, ...) {
 		return WEXITSTATUS(waitpid_status);
 	}
 
-	va_start(ap, command);
-	execlp(command, command, ap, (char *) NULL);
-	va_end(ap);
+	argv[0] = command;
+	argv[1] = arg;
+	argv[2] = NULL;
 
-	uwsgi_error("execlp()");
+	execvp(command, argv);
+
+	uwsgi_error("execvp()");
 	//never here
 	exit(1);
 }
diff --git a/uwsgi.h b/uwsgi.h
index a35e8b0a..e4765150 100644
--- a/uwsgi.h
+++ b/uwsgi.h
@@ -2048,7 +2048,7 @@ void uwsgi_set_cgroup(void);
 void uwsgi_add_sockets_to_queue(int);
 void uwsgi_del_sockets_from_queue(int);
 
-int uwsgi_run_command_and_wait(char *, ...);
+int uwsgi_run_command_and_wait(char *, char *);
 
 void uwsgi_manage_signal_cron(time_t);
 int uwsgi_run_command(char *);