1 files changed, 129 insertions, 0 deletions
diff --git a/crypto/initthread.c b/crypto/initthread.c
new file mode 100644
index 0000000000..6e56d47338
--- /dev/null
+++ b/crypto/initthread.c
@@ -0,0 +1,129 @@
+/*
+ * 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 <openssl/crypto.h>
+#include "internal/cryptlib_int.h"
+
+typedef struct thread_event_handler_st THREAD_EVENT_HANDLER;
+struct thread_event_handler_st {
+    OPENSSL_CTX *ctx;
+    ossl_thread_stop_handler_fn handfn;
+    THREAD_EVENT_HANDLER *next;
+};
+
+/*
+ * Since per-thread-specific-data destructors are not universally
+ * available, i.e. not on Windows, only below CRYPTO_THREAD_LOCAL key
+ * is assumed to have destructor associated. And then an effort is made
+ * to call this single destructor on non-pthread platform[s].
+ *
+ * Initial value is "impossible". It is used as guard value to shortcut
+ * destructor for threads terminating before libcrypto is initialized or
+ * after it's de-initialized. Access to the key doesn't have to be
+ * serialized for the said threads, because they didn't use libcrypto
+ * and it doesn't matter if they pick "impossible" or derefernce real
+ * key value and pull NULL past initialization in the first thread that
+ * intends to use libcrypto.
+ */
+static union {
+    long sane;
+    CRYPTO_THREAD_LOCAL value;
+} destructor_key = { -1 };
+
+static void ossl_init_thread_stop(THREAD_EVENT_HANDLER **hands);
+
+static void ossl_init_thread_destructor(void *hands)
+{
+    ossl_init_thread_stop((THREAD_EVENT_HANDLER **)hands);
+}
+
+int init_thread(void)
+{
+
+    if (!CRYPTO_THREAD_init_local(&destructor_key.value,
+                                  ossl_init_thread_destructor))
+        return 0;
+
+    return 1;
+}
+
+void cleanup_thread(void)
+{
+    CRYPTO_THREAD_cleanup_local(&destructor_key.value);
+    destructor_key.sane = -1;
+}
+
+static THREAD_EVENT_HANDLER **ossl_init_get_thread_local(int alloc)
+{
+    THREAD_EVENT_HANDLER **hands =
+        CRYPTO_THREAD_get_local(&destructor_key.value);
+
+    if (alloc) {
+        if (hands == NULL
+            && (hands = OPENSSL_zalloc(sizeof(*hands))) != NULL
+            && !CRYPTO_THREAD_set_local(&destructor_key.value, hands)) {
+            OPENSSL_free(hands);
+            return NULL;
+        }
+    } else {
+        CRYPTO_THREAD_set_local(&destructor_key.value, NULL);
+    }
+
+    return hands;
+}
+
+static void ossl_init_thread_stop(THREAD_EVENT_HANDLER **hands)
+{
+    THREAD_EVENT_HANDLER *curr, *prev = NULL;
+
+    /* Can't do much about this */
+    if (hands == NULL)
+        return;
+
+    curr = *hands;
+    while (curr != NULL) {
+        curr->handfn(curr->ctx);
+        prev = curr;
+        curr = curr->next;
+        OPENSSL_free(prev);
+    }
+
+    OPENSSL_free(hands);
+}
+
+void OPENSSL_thread_stop(void)
+{
+    if (destructor_key.sane != -1)
+        ossl_init_thread_stop(ossl_init_get_thread_local(0));
+}
+
+int ossl_init_thread_start(OPENSSL_CTX *ctx, ossl_thread_stop_handler_fn handfn)
+{
+    THREAD_EVENT_HANDLER **hands;
+    THREAD_EVENT_HANDLER *hand;
+
+    if (!OPENSSL_init_crypto(0, NULL))
+        return 0;
+
+    hands = ossl_init_get_thread_local(1);
+
+    if (hands == NULL)
+        return 0;
+
+    hand = OPENSSL_malloc(sizeof(*hand));
+    if (hand == NULL)
+        return 0;
+
+    hand->handfn = handfn;
+    hand->ctx = ctx;
+    hand->next = *hands;
+    *hands = hand;
+
+    return 1;
+}