/*

 * Copyright (c) 2014, 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

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, (void*)0xf000f000);

  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, (void*)0xf000f000);

  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