From b03311cadd3a6f931e176f97b97bd72be3ef96d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dag-Erling=20Sm=C3=B8rgrav?= <des@FreeBSD.org>
Date: Mon, 17 Apr 2023 19:49:13 +0000
Subject: [PATCH] renice: Avoid segfault if -n flag is given without argument.

Fixes:		65ee0a8495538
MFC after:	1 week
Sponsored by:	Klara, Inc.
Reviewed by:	kevans
Differential Revision:	https://reviews.freebsd.org/D39623
---
 usr.bin/renice/renice.c             | 2 +-
 usr.bin/renice/tests/renice_test.sh | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/usr.bin/renice/renice.c b/usr.bin/renice/renice.c
index 890d7043ebbd..42e93cce240e 100644
--- a/usr.bin/renice/renice.c
+++ b/usr.bin/renice/renice.c
@@ -94,7 +94,7 @@ main(int argc, char *argv[])
 			}
 			if (strcmp(*argv, "-n") == 0) {
 				/* may occur only once, prior to priority */
-				if (haveprio || incr)
+				if (haveprio || incr || argc < 2)
 					usage();
 				incr = true;
 				(void)argc--, argv++;
diff --git a/usr.bin/renice/tests/renice_test.sh b/usr.bin/renice/tests/renice_test.sh
index 9321e0f327ae..a6e8007ba35d 100644
--- a/usr.bin/renice/tests/renice_test.sh
+++ b/usr.bin/renice/tests/renice_test.sh
@@ -158,6 +158,11 @@ renice_delim_body() {
 	kill $pid
 }
 
+atf_test_case renice_incr_noarg
+renice_incr_noarg_body() {
+	atf_check -o empty -e ignore -s exit:1 renice -n
+}
+
 atf_init_test_cases() {
 	atf_add_test_case renice_abs_pid
 	atf_add_test_case renice_rel_pid
@@ -166,4 +171,5 @@ atf_init_test_cases() {
 	atf_add_test_case renice_abs_user
 	atf_add_test_case renice_rel_user
 	atf_add_test_case renice_delim
+	atf_add_test_case renice_incr_noarg
 }