libs/sig: consideration for sig_t.ctxt alignment

The flexible array of void *'s would just align to a pointer,
which may not be safe for all members of whatever gets shoved in
here.

In an effort to make it more robust, make it an array of a junk
drawer union of types.

1 files changed, 19 insertions, 1 deletions

diff --git a/src/libs/sig/sig.c b/src/libs/sig/sig.c
index fea83b6..865c6b4 100644
--- a/src/libs/sig/sig.c
+++ b/src/libs/sig/sig.c
@@ -4,10 +4,28 @@
 
 #include "sig.h"
 
+/* This is to try ensure ctxt's alignment accomodates all the base type sizes,
+ * it may waste some space in sig_t but since the caller supplies just a size
+ * via the supplied sig_ops_t.size(), we know nothing of the alignment reqs.
+ *
+ * XXX: If callers start using other types like xmmintrinsics __m128, this
+ * struct will have to get those added.
+ */
+typedef union sig_context_t {
+	float		f;
+	double		d;
+	long double	ld;
+	char		c;
+	short		s;
+	int		i;
+	long		l;
+	long long	ll;
+	void		*p;
+} sig_context_t;
 
 typedef struct sig_t {
 	const sig_ops_t	*ops;
-	void		*ctxt[];
+	sig_context_t	ctxt[];
 } sig_t;