1/*
2 * Copyright (c) 1997, 2018, 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 "jvm.h"
30#include "memory/allocation.inline.hpp"
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* const file, Elf_Shdr& shdr, int index) :
37 _next(NULL), _index(index), _section(file, shdr), _fd(file) {
38 _status = _section.status();
39}
40
41ElfStringTable::~ElfStringTable() {
42 if (_next != NULL) {
43 delete _next;
44 }
45}
46
47bool ElfStringTable::string_at(size_t pos, char* buf, int buflen) {
48 if (NullDecoder::is_error(get_status())) {
49 return false;
50 }
51
52 assert(buflen > 0, "no buffer");
53 if (pos >= _section.section_header()->sh_size) {
54 return false;
55 }
56
57 const char* data = (const char*)_section.section_data();
58 if (data != NULL) {
59 jio_snprintf(buf, buflen, "%s", data + pos);
60 return true;
61 } else { // no cache data, read from file instead
62 const Elf_Shdr* const shdr = _section.section_header();
63 MarkedFileReader mfd(_fd);
64 if (mfd.has_mark() &&
65 mfd.set_position(shdr->sh_offset + pos) &&
66 mfd.read((void*)buf, size_t(buflen))) {
67 buf[buflen - 1] = '\0';
68 return true;
69 } else {
70 // put it in error state to avoid retry
71 _status = NullDecoder::file_invalid;
72 return false;
73 }
74 }
75}
76
77#endif // !_WINDOWS && !__APPLE__
78