1 /*
2 * Copyright (c) 2016, 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 package jdk.tools.jaotc.binformat.elf;
25
26 import java.nio.ByteBuffer;
27 import java.nio.ByteOrder;
28
29 import jdk.tools.jaotc.binformat.elf.Elf;
30 import jdk.tools.jaotc.binformat.elf.Elf.Elf64_Ehdr;
31 import jdk.tools.jaotc.binformat.elf.Elf.Elf64_Shdr;
32 import jdk.tools.jaotc.binformat.elf.Elf.Elf64_Rel;
33 import jdk.tools.jaotc.binformat.elf.Elf.Elf64_Rela;
34 import jdk.tools.jaotc.binformat.elf.Elf.Elf64_Sym;
35 import jdk.tools.jaotc.binformat.elf.ElfByteBuffer;
36
37 public class ElfSection {
38 String name;
39 ByteBuffer section;
40 byte [] data;
41 boolean hasrelocations;
42 int sectionIndex;
43
44 /**
45 * String holding section name strings
46 */
47 private static StringBuilder sectNameTab = new StringBuilder();
48
49 /**
50 * Keeps track of bytes in section string table since strTabContent.length()
51 * is number of chars, not bytes.
52 */
53 private static int shStrTabNrOfBytes = 0;
54
55 public ElfSection(String sectName, byte [] sectData, int sectFlags,
56 int sectType, boolean hasRelocations, int align,
57 int sectIndex) {
58
59 section = ElfByteBuffer.allocate(Elf64_Shdr.totalsize);
60
61 // Return all 0's for NULL section
62 if (sectIndex == 0) {
63 sectNameTab.append('\0');
64 shStrTabNrOfBytes += 1;
65 data = null;
66 hasrelocations = false;
67 sectionIndex = 0;
68 return;
69 }
70
71 section.putInt(Elf64_Shdr.sh_name.off, shStrTabNrOfBytes);
72 sectNameTab.append(sectName).append('\0');
73 shStrTabNrOfBytes += (sectName.getBytes().length + 1);
74 name = sectName;
75
76 section.putInt(Elf64_Shdr.sh_type.off, sectType);
77 section.putLong(Elf64_Shdr.sh_flags.off, sectFlags);
78 section.putLong(Elf64_Shdr.sh_addr.off, 0);
79 section.putLong(Elf64_Shdr.sh_offset.off, 0);
80
81 if (sectName.equals(".shstrtab")) {
82 section.putLong(Elf64_Shdr.sh_size.off, shStrTabNrOfBytes);
83 data = sectNameTab.toString().getBytes();
84 }
85 else {
86 data = sectData;
87 section.putLong(Elf64_Shdr.sh_size.off, sectData.length);
88 }
89
90 section.putLong(Elf64_Shdr.sh_entsize.off, 0);
91
92 // Determine the entrysize
93 // based on type of section
94 switch (sectType) {
95 case Elf64_Shdr.SHT_SYMTAB:
96 section.putLong(Elf64_Shdr.sh_entsize.off, Elf64_Sym.totalsize);
97 break;
98 case Elf64_Shdr.SHT_RELA:
99 section.putLong(Elf64_Shdr.sh_entsize.off, Elf64_Rela.totalsize);
100 break;
101 case Elf64_Shdr.SHT_REL:
102 section.putLong(Elf64_Shdr.sh_entsize.off, Elf64_Rel.totalsize);
103 break;
104 default:
105 break;
106 }
107 section.putLong(Elf64_Shdr.sh_addralign.off, align);
108
109 hasrelocations = hasRelocations;
110 sectionIndex = sectIndex;
111 }
112
113 public String getName() {
114 return name;
115 }
116
117 public long getSize() {
118 return section.getLong(Elf64_Shdr.sh_size.off);
119 }
120
121 public int getDataAlign() {
122 return ((int)section.getLong(Elf64_Shdr.sh_addralign.off));
123 }
124
125 // Alignment requirements for the Elf64_Shdr structures
126 public static int getShdrAlign() {
127 return (4);
128 }
129
130 public byte[] getArray() {
131 return section.array();
132 }
133
134 public byte[] getDataArray() {
135 return data;
136 }
137
138 public void setOffset(long offset) {
139 section.putLong(Elf64_Shdr.sh_offset.off, offset);
140 }
141
142 public void setLink(int link) {
143 section.putInt(Elf64_Shdr.sh_link.off, link);
144 }
145
146 public void setInfo(int info) {
147 section.putInt(Elf64_Shdr.sh_info.off, info);
148 }
149
150 public long getOffset() {
151 return (section.getLong(Elf64_Shdr.sh_offset.off));
152 }
153
154 public boolean hasRelocations() {
155 return hasrelocations;
156 }
157
158 public int getSectionId() {
159 return sectionIndex;
160 }
161
162 }
163
164