From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 8 Nov 2018 08:33:31 +0000 (+0100)
Subject: unit: make UNIT() cast function deal with NULL pointers
X-Git-Tag: v240~384
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bbf11206230d1b089118971f98a047151cb5c4fa;p=thirdparty%2Fsystemd.git

unit: make UNIT() cast function deal with NULL pointers

Fixes: #10681
---

diff --git a/src/core/unit.h b/src/core/unit.h
index b6ef9d97ee6..c91fb49c609 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -582,7 +582,12 @@ extern const UnitVTable * const unit_vtable[_UNIT_TYPE_MAX];
         }
 
 /* For casting the various unit types into a unit */
-#define UNIT(u) (&(u)->meta)
+#define UNIT(u)                                         \
+        ({                                              \
+                typeof(u) _u_ = (u);                    \
+                Unit *_w_ = _u_ ? &(_u_)->meta : NULL;  \
+                _w_;                                    \
+        })
 
 #define UNIT_HAS_EXEC_CONTEXT(u) (UNIT_VTABLE(u)->exec_context_offset > 0)
 #define UNIT_HAS_CGROUP_CONTEXT(u) (UNIT_VTABLE(u)->cgroup_context_offset > 0)