Add a thread-properties API
(Based on proposal at https://sourceware.org/glibc/wiki/ThreadPropertiesAPI)

This includes API to:
 - locate static and dynamic TLS
 - register thread-exit and  dynamic TLS creation/destruction callbacks

Change-Id: Icd9d29a5b2f47495395645e19d3b2c96826f19c8
diff --git a/libc/include/sys/thread_properties.h b/libc/include/sys/thread_properties.h
new file mode 100644
index 0000000..b5d30c7
--- /dev/null
+++ b/libc/include/sys/thread_properties.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#pragma once
+
+/**
+ * @file thread_properties.h
+ * @brief Thread properties API.
+ *
+ * https://sourceware.org/glibc/wiki/ThreadPropertiesAPI
+ * API for querying various properties of the current thread, used mostly by
+ * the sanitizers.
+ *
+ * Available since API level 31.
+ *
+ */
+
+#include <sys/cdefs.h>
+#include <unistd.h>
+
+__BEGIN_DECLS
+
+/**
+ * Gets the bounds of static TLS for the current thread.
+ *
+ * Available since API level 31.
+ */
+void __libc_get_static_tls_bounds(void** __static_tls_begin,
+                                  void** __static_tls_end) __INTRODUCED_IN(31);
+
+
+/**
+ * Registers callback to be called right before the thread is dead.
+ * The callbacks are chained, they are called in the order opposite to the order
+ * they were registered.
+ *
+ * The callbacks must be registered only before any threads were created.
+ * No signals may arrive during the calls to these callbacks.
+ * The callbacks may not access the thread's dynamic TLS because they will have
+ * been freed by the time these callbacks are invoked.
+ *
+ * Available since API level 31.
+ */
+void __libc_register_thread_exit_callback(void (*__cb)(void)) __INTRODUCED_IN(31);
+
+/**
+ * Iterates over all dynamic TLS chunks for the given thread.
+ * The thread should have been suspended. It is undefined-behaviour if there is concurrent
+ * modification of the target thread's dynamic TLS.
+ *
+ * Available since API level 31.
+ */
+void __libc_iterate_dynamic_tls(pid_t __tid,
+                                void (*__cb)(void* __dynamic_tls_begin,
+                                             void* __dynamic_tls_end,
+                                             size_t __dso_id,
+                                             void* __arg),
+                                void* __arg) __INTRODUCED_IN(31);
+
+/**
+ * Register on_creation and on_destruction callbacks, which will be called after a dynamic
+ * TLS creation and before a dynamic TLS destruction, respectively.
+ *
+ * Available since API level 31.
+ */
+void __libc_register_dynamic_tls_listeners(
+    void (*__on_creation)(void* __dynamic_tls_begin,
+                          void* __dynamic_tls_end),
+    void (*__on_destruction)(void* __dynamic_tls_begin,
+                             void* __dynamic_tls_end)) __INTRODUCED_IN(31);
+
+__END_DECLS