From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Sun, 1 Oct 2023 11:57:12 +0000 (+0200)
Subject: include/c.h: add helpers for unaligned structure access
X-Git-Tag: v2.40-rc1~221^2~1
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=68459714838c8c0c2d34b6d658638f5d59298bc7;p=thirdparty%2Futil-linux.git

include/c.h: add helpers for unaligned structure access

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
---

diff --git a/include/c.h b/include/c.h
index 752f568c50..224a8e54fe 100644
--- a/include/c.h
+++ b/include/c.h
@@ -213,6 +213,14 @@
 	(type *)( (char *)__mptr - offsetof(type,member) );})
 #endif
 
+#define read_unaligned_member(p, m) __extension__ ({          \
+	size_t offset = offsetof(__typeof__(* p), m);         \
+	__typeof__(p->m) v;                                   \
+	memcpy(&v, ((unsigned char *)p) + offset, sizeof(v)); \
+	v; })
+
+#define member_ptr(p, m) (((unsigned char *)p) + offsetof(__typeof__(*p), m))
+
 #ifndef HAVE_PROGRAM_INVOCATION_SHORT_NAME
 # ifdef HAVE___PROGNAME
 extern char *__progname;