Provide basis for fixing lhash code

Following on from the earlier safestack work we provide the basis for
fixing the lhash code such that unused static inline functions do not
cause linker errors for applications including those headers.

This brings the lhash code into line with the safestack code.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/12860)

1 files changed, 36 insertions, 0 deletions

diff --git a/include/openssl/lhash.h b/include/openssl/lhash.h
index 5ad9b16ab2..816b613eaf 100644
--- a/include/openssl/lhash.h
+++ b/include/openssl/lhash.h
@@ -125,6 +125,42 @@ void OPENSSL_LH_node_usage_stats_bio(const OPENSSL_LHASH *lh, BIO *out);
 
 # define LHASH_OF(type) struct lhash_st_##type
 
+/* Helper macro for internal use */
+# define DEFINE_LHASH_OF_INTERNAL(type) \
+    LHASH_OF(type) { union lh_##type##_dummy { void* d1; unsigned long d2; int d3; } dummy; }; \
+    typedef int (*lh_##type##_compfunc)(const type *a, const type *b); \
+    typedef unsigned long (*lh_##type##_hashfunc)(const type *a); \
+    typedef void (*lh_##type##_doallfunc)(type *a); \
+    static ossl_unused ossl_inline type *ossl_check_##type##_lh_plain_type(type *ptr) \
+    { \
+        return ptr; \
+    } \
+    static ossl_unused ossl_inline const type *ossl_check_const_##type##_lh_plain_type(const type *ptr) \
+    { \
+        return ptr; \
+    } \
+    static ossl_unused ossl_inline const OPENSSL_LHASH *ossl_check_const_##type##_lh_type(const LHASH_OF(type) *lh) \
+    { \
+        return (const OPENSSL_LHASH *)lh; \
+    } \
+    static ossl_unused ossl_inline OPENSSL_LHASH *ossl_check_##type##_lh_type(LHASH_OF(type) *lh) \
+    { \
+        return (OPENSSL_LHASH *)lh; \
+    } \
+    static ossl_unused ossl_inline OPENSSL_LH_COMPFUNC ossl_check_##type##_lh_compfunc_type(lh_##type##_compfunc cmp) \
+    { \
+        return (OPENSSL_LH_COMPFUNC)cmp; \
+    } \
+    static ossl_unused ossl_inline OPENSSL_LH_HASHFUNC ossl_check_##type##_lh_hashfunc_type(lh_##type##_hashfunc hfn) \
+    { \
+        return (OPENSSL_LH_HASHFUNC)hfn; \
+    } \
+    static ossl_unused ossl_inline OPENSSL_LH_DOALL_FUNC ossl_check_##type##_lh_doallfunc_type(lh_##type##_doallfunc dfn) \
+    { \
+        return (OPENSSL_LH_DOALL_FUNC)dfn; \
+    } \
+    LHASH_OF(type)
+
 # define DEFINE_LHASH_OF(type) \
     LHASH_OF(type) { union lh_##type##_dummy { void* d1; unsigned long d2; int d3; } dummy; }; \
     static ossl_unused ossl_inline LHASH_OF(type) *lh_##type##_new(unsigned long (*hfn)(const type *), \