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 /*

  * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "memory/allocation.hpp"

 #include "memory/allocation.inline.hpp"

 #include "memory/guardedMemory.hpp"

 #include "runtime/os.hpp"

 void* GuardedMemory::wrap_copy(const void* ptr, const size_t len, const void* tag) {

   size_t total_sz = GuardedMemory::get_total_size(len);

   void* outerp = os::malloc(total_sz, mtInternal);

   if (outerp != NULL) {

     GuardedMemory guarded(outerp, len, tag);

     void* innerp = guarded.get_user_ptr();

     memcpy(innerp, ptr, len);

     return innerp;

   }

   return NULL; // OOM

 }

 bool GuardedMemory::free_copy(void* p) {

   if (p == NULL) {

     return true;

   }

   GuardedMemory guarded((u_char*)p);

   bool verify_ok = guarded.verify_guards();

   /* always attempt to free, pass problem on to any nested memchecker */

   os::free(guarded.release_for_freeing());

   return verify_ok;

 }

 void GuardedMemory::print_on(outputStream* st) const {

   if (_base_addr == NULL) {

     st->print_cr("GuardedMemory(" PTR_FORMAT ") not associated to any memory", p2i(this));

     return;

   }

   st->print_cr("GuardedMemory(" PTR_FORMAT ") base_addr=" PTR_FORMAT

       " tag=" PTR_FORMAT " user_size=" SIZE_FORMAT " user_data=" PTR_FORMAT,

       p2i(this), p2i(_base_addr), p2i(get_tag()), get_user_size(), p2i(get_user_ptr()));

   Guard* guard = get_head_guard();

   st->print_cr("  Header guard @" PTR_FORMAT " is %s", p2i(guard), (guard->verify() ? "OK" : "BROKEN"));

   guard = get_tail_guard();

   st->print_cr("  Trailer guard @" PTR_FORMAT " is %s", p2i(guard), (guard->verify() ? "OK" : "BROKEN"));

   u_char udata = *get_user_ptr();

   switch (udata) {

   case uninitBlockPad:

     st->print_cr("  User data appears unused");

     break;

   case freeBlockPad:

     st->print_cr("  User data appears to have been freed");

     break;

   default:

     st->print_cr("  User data appears to be in use");

     break;

   }

 }

 // test code...

 #ifndef PRODUCT

 #define GEN_PURPOSE_TAG ((void *) ((uintptr_t)0xf000f000))

 static void guarded_memory_test_check(void* p, size_t sz, void* tag) {

   assert(p != NULL, "NULL pointer given to check");

   u_char* c = (u_char*) p;

   GuardedMemory guarded(c);

   assert(guarded.get_tag() == tag, "Tag is not the same as supplied");

   assert(guarded.get_user_ptr() == c, "User pointer is not the same as supplied");

   assert(guarded.get_user_size() == sz, "User size is not the same as supplied");

   assert(guarded.verify_guards(), "Guard broken");

 }

 void GuardedMemory::test_guarded_memory() {

   // Test the basic characteristics...

   size_t total_sz = GuardedMemory::get_total_size(1);

   assert(total_sz > 1 && total_sz >= (sizeof(GuardHeader) + 1 + sizeof(Guard)), "Unexpected size");

   u_char* basep = (u_char*) os::malloc(total_sz, mtInternal);

   GuardedMemory guarded(basep, 1, GEN_PURPOSE_TAG);

   assert(*basep == badResourceValue, "Expected guard in the form of badResourceValue");

   u_char* userp = guarded.get_user_ptr();

   assert(*userp == uninitBlockPad, "Expected uninitialized data in the form of uninitBlockPad");

   guarded_memory_test_check(userp, 1, GEN_PURPOSE_TAG);

   void* freep = guarded.release_for_freeing();

   assert((u_char*)freep == basep, "Expected the same pointer guard was ");

   assert(*userp == freeBlockPad, "Expected user data to be free block padded");

   assert(!guarded.verify_guards(), "Expected failed");

   os::free(freep);

   // Test a number of odd sizes...

   size_t sz = 0;

   do {

     void* p = os::malloc(GuardedMemory::get_total_size(sz), mtInternal);

     void* up = guarded.wrap_with_guards(p, sz, (void*)1);

     memset(up, 0, sz);

     guarded_memory_test_check(up, sz, (void*)1);

     os::free(guarded.release_for_freeing());

     sz = (sz << 4) + 1;

   } while (sz < (256 * 1024));

   // Test buffer overrun into head...

   basep = (u_char*) os::malloc(GuardedMemory::get_total_size(1), mtInternal);

   guarded.wrap_with_guards(basep, 1);

   *basep = 0;

   assert(!guarded.verify_guards(), "Expected failure");

   os::free(basep);

   // Test buffer overrun into tail with a number of odd sizes...

   sz = 1;

   do {

     void* p = os::malloc(GuardedMemory::get_total_size(sz), mtInternal);

     void* up = guarded.wrap_with_guards(p, sz, (void*)1);

     memset(up, 0, sz + 1); // Buffer-overwrite (within guard)

     assert(!guarded.verify_guards(), "Guard was not broken as expected");

     os::free(guarded.release_for_freeing());

     sz = (sz << 4) + 1;

   } while (sz < (256 * 1024));

   // Test wrap_copy/wrap_free...

   assert(GuardedMemory::free_copy(NULL), "Expected free NULL to be OK");

   const char* str = "Check my bounds out";

   size_t str_sz = strlen(str) + 1;

   char* str_copy = (char*) GuardedMemory::wrap_copy(str, str_sz);

   guarded_memory_test_check(str_copy, str_sz, NULL);

   assert(strcmp(str, str_copy) == 0, "Not identical copy");

   assert(GuardedMemory::free_copy(str_copy), "Free copy failed to verify");

   void* no_data = NULL;

   void* no_data_copy = GuardedMemory::wrap_copy(no_data, 0);

   assert(GuardedMemory::free_copy(no_data_copy), "Expected valid guards even for no data copy");

 }

 #endif // !PRODUCT