Add a CRYPTO_library_init and static-initializer-less build option.

Chromium does not like static initializers, and the CPU logic uses one to
initialize CPU bits. However, the crypto library lacks an explicit
initialization function, which could complicate (no compile-time errors)
porting existing code which uses crypto/, but not ssl/.

Add an explicit CRYPTO_library_init function, but make it a no-op by default.
It only does anything (and is required) if building with
BORINGSSL_NO_STATIC_INITIALIZER.

Change-Id: I6933bdc3447fb382b1f87c788e5b8142d6f3fe39
Reviewed-on: https://boringssl-review.googlesource.com/1770
Reviewed-by: Adam Langley <agl@google.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/crypto/crypto.c b/crypto/crypto.c
new file mode 100644
index 00000000..78241daa
--- /dev/null
+++ b/crypto/crypto.c
@@ -0,0 +1,60 @@
+/* Copyright (c) 2014, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/crypto.h>
+
+#include "internal.h"
+
+
+/* Currently, the only configurations which require a static initializer are x86
+ * and x86_64. Don't bother emitting one in other cases. */
+#if !defined(OPENSSL_X86) && !defined(OPENSSL_X86_64) && \
+    !defined(BORINGSSL_NO_STATIC_INITIALIZER)
+#define BORINGSSL_NO_STATIC_INITIALIZER
+#endif
+
+#if defined(OPENSSL_WINDOWS)
+#define OPENSSL_CDECL __cdecl
+#else
+#define OPENSSL_CDECL
+#endif
+
+#if !defined(BORINGSSL_NO_STATIC_INITIALIZER)
+#if !defined(OPENSSL_WINDOWS)
+static void do_library_init(void) __attribute__ ((constructor));
+#else
+#pragma section(".CRT$XCU", read)
+static void __cdecl do_library_init(void);
+__declspec(allocate(".CRT$XCU")) void(*library_init_constructor)(void) =
+    do_library_init;
+#endif
+#endif  /* !BORINGSSL_NO_STATIC_INITIALIZER */
+
+/* do_library_init is the actual initialization function. If
+ * BORINGSSL_NO_STATIC_INITIALIZER isn't defined, this is set as a static
+ * initializer. Otherwise, it is called by CRYPTO_library_init. */
+static void OPENSSL_CDECL do_library_init(void) {
+#if defined(OPENSSL_X86) || defined(OPENSSL_X86_64)
+  OPENSSL_cpuid_setup();
+#endif
+}
+
+void CRYPTO_library_init(void) {
+  /* TODO(davidben): It would be tidier if this build knob could be replaced
+   * with an internal lazy-init mechanism that would handle things correctly
+   * in-library. */
+#if defined(BORINGSSL_NO_STATIC_INITIALIZER)
+  do_library_init();
+#endif
+}