Add an OpenSSL library context

The context builds on CRYPTO_EX_DATA, allowing it to be dynamically
extended with new data from the different parts of libcrypto.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8225)

1 files changed, 110 insertions, 0 deletions

diff --git a/crypto/context.c b/crypto/context.c
new file mode 100644
index 0000000000..752711b9a4
--- /dev/null
+++ b/crypto/context.c
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include "internal/cryptlib.h"
+#include "internal/thread_once.h"
+
+struct openssl_ctx_st {
+    CRYPTO_RWLOCK *lock;
+    CRYPTO_EX_DATA data;
+};
+
+static OPENSSL_CTX default_context;
+
+static int context_init(OPENSSL_CTX *ctx)
+{
+    return (ctx->lock = CRYPTO_THREAD_lock_new()) != NULL
+        && CRYPTO_new_ex_data(CRYPTO_EX_INDEX_OPENSSL_CTX, NULL,
+                              &ctx->data);
+}
+
+static int context_deinit(OPENSSL_CTX *ctx)
+{
+    CRYPTO_free_ex_data(CRYPTO_EX_INDEX_OPENSSL_CTX, NULL, &ctx->data);
+    CRYPTO_THREAD_lock_free(ctx->lock);
+    return 1;
+}
+
+static CRYPTO_ONCE default_context_init = CRYPTO_ONCE_STATIC_INIT;
+static void do_default_context_deinit(void)
+{
+    context_deinit(&default_context);
+}
+DEFINE_RUN_ONCE_STATIC(do_default_context_init)
+{
+    return OPENSSL_init_crypto(0, NULL)
+        && context_init(&default_context)
+        && OPENSSL_atexit(do_default_context_deinit);
+}
+
+OPENSSL_CTX *OPENSSL_CTX_new(void)
+{
+    OPENSSL_CTX *ctx = OPENSSL_zalloc(sizeof(*ctx));
+
+    if (ctx != NULL && !context_init(ctx)) {
+        OPENSSL_CTX_free(ctx);
+        ctx = NULL;
+    }
+    return ctx;
+}
+
+void OPENSSL_CTX_free(OPENSSL_CTX *ctx)
+{
+    if (ctx != NULL)
+        context_deinit(ctx);
+    OPENSSL_free(ctx);
+}
+
+static void openssl_ctx_generic_new(void *parent_ign, void *ptr_ign,
+                                    CRYPTO_EX_DATA *ad, int index,
+                                    long argl_ign, void *argp)
+{
+    const OPENSSL_CTX_METHOD *meth = argp;
+    void *ptr = meth->new_func();
+
+    if (ptr != NULL)
+        CRYPTO_set_ex_data(ad, index, ptr);
+}
+static void openssl_ctx_generic_free(void *parent_ign, void *ptr,
+                                     CRYPTO_EX_DATA *ad, int index,
+                                     long argl_ign, void *argp)
+{
+    const OPENSSL_CTX_METHOD *meth = argp;
+
+    meth->free_func(ptr);
+}
+int openssl_ctx_new_index(const OPENSSL_CTX_METHOD *meth)
+{
+    return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_OPENSSL_CTX, 0, (void *)meth,
+                                   openssl_ctx_generic_new, NULL,
+                                   openssl_ctx_generic_free);
+}
+
+void *openssl_ctx_get_data(OPENSSL_CTX *ctx, int index)
+{
+    void *data = NULL;
+
+    if (ctx == NULL) {
+        if (!RUN_ONCE(&default_context_init, do_default_context_init))
+            return 0;
+        ctx = &default_context;
+    }
+
+    CRYPTO_THREAD_read_lock(ctx->lock);
+
+    /* The alloc call ensures there's a value there */
+    if (CRYPTO_alloc_ex_data(CRYPTO_EX_INDEX_OPENSSL_CTX, NULL,
+                             &ctx->data, index))
+        data = CRYPTO_get_ex_data(&ctx->data, index);
+
+    CRYPTO_THREAD_unlock(ctx->lock);
+
+    return data;
+}
+