From 735e69de93dc746ded8c03eed4c193b5299492cf Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Thu, 17 Jan 2019 13:10:39 -0500
Subject: [PATCH 164/220] Make it possible to subtract conditions from debug=

This makes it so you can do set debug to "all,-scripting,-lexer" and get the
obvious outcome.  Any negation present will take preference over that
conditional, so "all,-scripting,scripting" is the same thing as
"all,-scripting".

Signed-off-by: Peter Jones <pjones@redhat.com>
---
 grub-core/kern/misc.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index e21dd44..18a7dbf 100644
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -163,12 +163,24 @@ int
 grub_debug_enabled (const char * condition)
 {
   const char *debug;
+  char *negcond;
+  int negated = 0;
 
   debug = grub_env_get ("debug");
   if (!debug)
     return 0;
 
-  if (grub_strword (debug, "all") || grub_strword (debug, condition))
+  negcond = grub_zalloc (grub_strlen (condition) + 2);
+  if (negcond)
+    {
+      grub_strcpy (negcond, "-");
+      grub_strcpy (negcond+1, condition);
+      negated = grub_strword (debug, negcond);
+      grub_free (negcond);
+    }
+
+  if (!negated &&
+      (grub_strword (debug, "all") || grub_strword (debug, condition)))
     return 1;
 
   return 0;
-- 
1.8.3.1