1/*
2 * Copyright (c) 1997, 2017, 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
27#if !defined(_WINDOWS) && !defined(__APPLE__)
28
29#include "memory/allocation.inline.hpp"
30#include "prims/jvm.h"
31#include "runtime/os.hpp"
32#include "utilities/elfStringTable.hpp"
33
34// We will try to load whole string table into memory if we can.
35// Otherwise, fallback to more expensive file operation.
36ElfStringTable::ElfStringTable(FILE* file, Elf_Shdr shdr, int index) {
37  assert(file, "null file handle");
38  m_table = NULL;
39  m_index = index;
40  m_next = NULL;
41  m_file = file;
42  m_status = NullDecoder::no_error;
43
44  // try to load the string table
45  long cur_offset = ftell(file);
46  m_table = (char*)os::malloc(sizeof(char) * shdr.sh_size, mtInternal);
47  if (m_table != NULL) {
48    // if there is an error, mark the error
49    if (fseek(file, shdr.sh_offset, SEEK_SET) ||
50      fread((void*)m_table, shdr.sh_size, 1, file) != 1 ||
51      fseek(file, cur_offset, SEEK_SET)) {
52      m_status = NullDecoder::file_invalid;
53      os::free((void*)m_table);
54      m_table = NULL;
55    }
56  } else {
57    memcpy(&m_shdr, &shdr, sizeof(Elf_Shdr));
58  }
59}
60
61ElfStringTable::~ElfStringTable() {
62  if (m_table != NULL) {
63    os::free((void*)m_table);
64  }
65
66  if (m_next != NULL) {
67    delete m_next;
68  }
69}
70
71bool ElfStringTable::string_at(int pos, char* buf, int buflen) {
72  if (NullDecoder::is_error(m_status)) {
73    return false;
74  }
75  if (m_table != NULL) {
76    jio_snprintf(buf, buflen, "%s", (const char*)(m_table + pos));
77    return true;
78  } else {
79    long cur_pos = ftell(m_file);
80    if (cur_pos == -1 ||
81      fseek(m_file, m_shdr.sh_offset + pos, SEEK_SET) ||
82      fread(buf, 1, buflen, m_file) <= 0 ||
83      fseek(m_file, cur_pos, SEEK_SET)) {
84      m_status = NullDecoder::file_invalid;
85      return false;
86    }
87    return true;
88  }
89}
90
91#endif // !_WINDOWS && !__APPLE__
92