1 /*
   2  * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classFileStream.hpp"
  27 #include "classfile/classLoader.hpp"
  28 #include "classfile/dictionary.hpp"
  29 #include "classfile/vmSymbols.hpp"
  30 #include "memory/resourceArea.hpp"
  31 
  32 const bool ClassFileStream::verify = true;
  33 const bool ClassFileStream::no_verification = false;
  34 
  35 void ClassFileStream::truncated_file_error(TRAPS) const {
  36   THROW_MSG(vmSymbols::java_lang_ClassFormatError(), "Truncated class file");
  37 }
  38 
  39 ClassFileStream::ClassFileStream(const u1* buffer,
  40                                  int length,
  41                                  const char* source,
  42                                  bool verify_stream) :
  43   _buffer_start(buffer),
  44   _buffer_end(buffer + length),
  45   _current(buffer),
  46   _source(source),
  47   _need_verify(verify_stream) {}
  48 
  49 const u1* ClassFileStream::clone_buffer() const {
  50   u1* const new_buffer_start = NEW_RESOURCE_ARRAY(u1, length());
  51   memcpy(new_buffer_start, _buffer_start, length());
  52   return new_buffer_start;
  53 }
  54 
  55 const char* const ClassFileStream::clone_source() const {
  56   const char* const src = source();
  57   char* source_copy = NULL;
  58   if (src != NULL) {
  59     size_t source_len = strlen(src);
  60     source_copy = NEW_RESOURCE_ARRAY(char, source_len + 1);
  61     strncpy(source_copy, src, source_len + 1);
  62   }
  63   return source_copy;
  64 }
  65 
  66 // Caller responsible for ResourceMark
  67 // clone stream with a rewound position
  68 const ClassFileStream* ClassFileStream::clone() const {
  69   const u1* const new_buffer_start = clone_buffer();
  70   return new ClassFileStream(new_buffer_start,
  71                              length(),
  72                              clone_source(),
  73                              need_verify());
  74 }
  75 
  76 u1 ClassFileStream::get_u1(TRAPS) const {
  77   if (_need_verify) {
  78     guarantee_more(1, CHECK_0);
  79   } else {
  80     assert(1 <= _buffer_end - _current, "buffer overflow");
  81   }
  82   return *_current++;
  83 }
  84 
  85 u2 ClassFileStream::get_u2(TRAPS) const {
  86   if (_need_verify) {
  87     guarantee_more(2, CHECK_0);
  88   } else {
  89     assert(2 <= _buffer_end - _current, "buffer overflow");
  90   }
  91   const u1* tmp = _current;
  92   _current += 2;
  93   return Bytes::get_Java_u2((address)tmp);
  94 }
  95 
  96 u4 ClassFileStream::get_u4(TRAPS) const {
  97   if (_need_verify) {
  98     guarantee_more(4, CHECK_0);
  99   } else {
 100     assert(4 <= _buffer_end - _current, "buffer overflow");
 101   }
 102   const u1* tmp = _current;
 103   _current += 4;
 104   return Bytes::get_Java_u4((address)tmp);
 105 }
 106 
 107 u8 ClassFileStream::get_u8(TRAPS) const {
 108   if (_need_verify) {
 109     guarantee_more(8, CHECK_0);
 110   } else {
 111     assert(8 <= _buffer_end - _current, "buffer overflow");
 112   }
 113   const u1* tmp = _current;
 114   _current += 8;
 115   return Bytes::get_Java_u8((address)tmp);
 116 }
 117 
 118 void ClassFileStream::skip_u1(int length, TRAPS) const {
 119   if (_need_verify) {
 120     guarantee_more(length, CHECK);
 121   }
 122   _current += length;
 123 }
 124 
 125 void ClassFileStream::skip_u2(int length, TRAPS) const {
 126   if (_need_verify) {
 127     guarantee_more(length * 2, CHECK);
 128   }
 129   _current += length * 2;
 130 }
 131 
 132 void ClassFileStream::skip_u4(int length, TRAPS) const {
 133   if (_need_verify) {
 134     guarantee_more(length * 4, CHECK);
 135   }
 136   _current += length * 4;
 137 }
 138 
 139 uint64_t ClassFileStream::compute_fingerprint() const {
 140   int classfile_size = length();
 141   int classfile_crc = ClassLoader::crc32(0, (const char*)buffer(), length());
 142   uint64_t fingerprint = (uint64_t(classfile_size) << 32) | uint64_t(uint32_t(classfile_crc));
 143   assert(fingerprint != 0, "must not be zero");
 144 
 145   return fingerprint;
 146 }