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 }