Add visibility rules.

This change marks public symbols as dynamically exported. This means
that it becomes viable to build a shared library of libcrypto and libssl
with -fvisibility=hidden.

On Windows, one not only needs to mark functions for export in a
component, but also for import when using them from a different
component. Because of this we have to build with
|BORINGSSL_IMPLEMENTATION| defined when building the code. Other
components, when including our headers, won't have that defined and then
the |OPENSSL_EXPORT| tag becomes an import tag instead. See the #defines
in base.h

In the asm code, symbols are now hidden by default and those that need
to be exported are wrapped by a C function.

In order to support Chromium, a couple of libssl functions were moved to
ssl.h from ssl_locl.h: ssl_get_new_session and ssl_update_cache.

Change-Id: Ib4b76e2f1983ee066e7806c24721e8626d08a261
Reviewed-on: https://boringssl-review.googlesource.com/1350
Reviewed-by: Adam Langley <agl@google.com>

1 files changed, 10 insertions, 9 deletions

diff --git a/include/openssl/mem.h b/include/openssl/mem.h
index 0d04c95b..293e04bf 100644
--- a/include/openssl/mem.h
+++ b/include/openssl/mem.h
@@ -82,29 +82,29 @@ void *OPENSSL_realloc_clean(void *ptr, size_t old_size, size_t new_size);
 
 /* OPENSSL_cleanse zeros out |len| bytes of memory at |ptr|. This is similar to
  * |memset_s| from C11. */
-void OPENSSL_cleanse(void *ptr, size_t len);
+OPENSSL_EXPORT void OPENSSL_cleanse(void *ptr, size_t len);
 
 /* CRYPTO_memcmp returns zero iff the |len| bytes at |a| and |b| are equal. It
  * takes an amount of time dependent on |len|, but independent of the contents
  * of |a| and |b|. Unlike memcmp, it cannot be used to put elements into a
  * defined order as the return value when a != b is undefined, other than to be
  * non-zero. */
-int CRYPTO_memcmp(const void *a, const void *b, size_t len);
+OPENSSL_EXPORT int CRYPTO_memcmp(const void *a, const void *b, size_t len);
 
 /* OPENSSL_hash32 implements the 32 bit, FNV-1a hash. */
-uint32_t OPENSSL_hash32(const void *ptr, size_t len);
+OPENSSL_EXPORT uint32_t OPENSSL_hash32(const void *ptr, size_t len);
 
 /* OPENSSL_strdup has the same behaviour as strdup(3). */
-char *OPENSSL_strdup(const char *s);
+OPENSSL_EXPORT char *OPENSSL_strdup(const char *s);
 
 /* OPENSSL_strnlen has the same behaviour as strnlen(3). */
-size_t OPENSSL_strnlen(const char *s, size_t len);
+OPENSSL_EXPORT size_t OPENSSL_strnlen(const char *s, size_t len);
 
 /* OPENSSL_strcasecmp has the same behaviour as strcasecmp(3). */
-int OPENSSL_strcasecmp(const char *a, const char *b);
+OPENSSL_EXPORT int OPENSSL_strcasecmp(const char *a, const char *b);
 
 /* OPENSSL_strncasecmp has the same behaviour as strncasecmp(3). */
-int OPENSSL_strncasecmp(const char *a, const char *b, size_t n);
+OPENSSL_EXPORT int OPENSSL_strncasecmp(const char *a, const char *b, size_t n);
 
 /* DECIMAL_SIZE returns an upper bound for the length of the decimal
  * representation of the given type. */
@@ -120,10 +120,11 @@ int OPENSSL_strncasecmp(const char *a, const char *b, size_t n);
 #else
 #define __bio_h__attr__(x)
 #endif
-int BIO_snprintf(char *buf, size_t n, const char *format, ...)
+OPENSSL_EXPORT int BIO_snprintf(char *buf, size_t n, const char *format, ...)
     __bio_h__attr__((__format__(__printf__, 3, 4)));
 
-int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args)
+OPENSSL_EXPORT int BIO_vsnprintf(char *buf, size_t n, const char *format,
+                                 va_list args)
     __bio_h__attr__((__format__(__printf__, 3, 0)));
 #undef __bio_h__attr__