Add execinfo functionality.
Bug: 27877410
Test: Add new unit tests.
Change-Id: Id5d7eb27a23f50e99a04f5ee1ab64047ba269bab
diff --git a/libc/include/execinfo.h b/libc/include/execinfo.h
new file mode 100644
index 0000000..347ae92
--- /dev/null
+++ b/libc/include/execinfo.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2021 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
+
+#include <sys/cdefs.h>
+
+/**
+ * @file execinfo.h
+ * @brief Functions to do in process backtracing.
+ */
+
+__BEGIN_DECLS
+
+/**
+ * [backtrace(3)](https://man7.org/linux/man-pages/man3/backtrace.3.html)
+ * Saves a backtrace for the current call in the array pointed to by buffer.
+ * "size" indicates the maximum number of void* pointers that can be set.
+ *
+ * Returns the number of addresses stored in "buffer", which is not greater
+ * than "size". If the return value is equal to "size" then the number of
+ * addresses may have been truncated.
+ *
+ * Available since API level 33.
+ */
+int backtrace(void** buffer, int size) __INTRODUCED_IN(33);
+
+/**
+ * [backtrace_symbols(3)](https://man7.org/linux/man-pages/man3/backtrace_symbols.3.html)
+ * Given an array of void* pointers, translate the addresses into an array
+ * of strings that represent the backtrace.
+ *
+ * Returns a pointer to allocated memory, on error NULL is returned. It is
+ * the responsibility of the caller to free the returned memory.
+ *
+ * Available since API level 33.
+ */
+char** backtrace_symbols(void* const* buffer, int size) __INTRODUCED_IN(33);
+
+/**
+ * [backtrace_symbols_fd(3)](https://man7.org/linux/man-pages/man3/backtrace_symbols_fd.3.html)
+ * Given an array of void* pointers, translate the addresses into an array
+ * of strings that represent the backtrace and write to the file represented
+ * by "fd". The file is written such that one line equals one void* address.
+ *
+ * Available since API level 33.
+ */
+void backtrace_symbols_fd(void* const* buffer, int size, int fd) __INTRODUCED_IN(33);
+
+__END_DECLS