From e71bab696feafed19360e4e00728a59bfb11c875 Mon Sep 17 00:00:00 2001
From: Warner Losh <imp@FreeBSD.org>
Date: Sat, 25 Feb 2017 00:09:12 +0000
Subject: [PATCH] Exit with usage if argv[1] is NULL in dispatch. This fixes
 core dumps when a command has subcommands, but the user doesn't give the
 parameters on the command line.

Sponsored by: Netflix
---
 sbin/nvmecontrol/nvmecontrol.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sbin/nvmecontrol/nvmecontrol.c b/sbin/nvmecontrol/nvmecontrol.c
index 52dccb411bf9..6c658d24b39c 100644
--- a/sbin/nvmecontrol/nvmecontrol.c
+++ b/sbin/nvmecontrol/nvmecontrol.c
@@ -75,6 +75,11 @@ dispatch(int argc, char *argv[], struct nvme_function *tbl)
 {
 	struct nvme_function *f = tbl;
 
+	if (argv[1] == NULL) {
+		gen_usage(tbl);
+		return;
+	}
+
 	while (f->name != NULL) {
 		if (strcmp(argv[1], f->name) == 0)
 			f->fn(argc-1, &argv[1]);