1 /*
2 * Copyright (c) 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.macho;
25
26 import java.nio.ByteBuffer;
27 import java.nio.ByteOrder;
28 import java.util.ArrayList;
29
30 import jdk.tools.jaotc.binformat.macho.MachO;
31 import jdk.tools.jaotc.binformat.macho.MachO.symtab_command;
32 import jdk.tools.jaotc.binformat.macho.MachO.nlist_64;
33 import jdk.tools.jaotc.binformat.macho.MachOSymbol;
34 import jdk.tools.jaotc.binformat.macho.MachOByteBuffer;
35
36 public class MachOSymtab {
37
38 /**
39 * ByteBuffer holding the LC_SYMTAB command contents
40 */
41 ByteBuffer symtabCmd;
42
43 /**
44 * ByteBuffer holding the symbol table entries and strings
45 */
46 ByteBuffer symtabData;
47
48 int symtabDataSize;
49
50 ArrayList<MachOSymbol>localSymbols = new ArrayList<MachOSymbol>();
51 ArrayList<MachOSymbol>globalSymbols = new ArrayList<MachOSymbol>();
52 ArrayList<MachOSymbol>undefSymbols = new ArrayList<MachOSymbol>();
53
54 /**
55 * number of symbols added
56 */
57 int symbolCount;
58
59 /**
60 * String holding symbol table strings
61 */
62 private StringBuilder strTabContent = new StringBuilder();
63
64 /**
65 * Keeps track of bytes in string table since strTabContent.length()
66 * is number of chars, not bytes.
67 */
68 private int strTabNrOfBytes = 0;
69
70 public MachOSymtab() {
71 symtabCmd = MachOByteBuffer.allocate(symtab_command.totalsize);
72
73 symtabCmd.putInt(symtab_command.cmd.off, symtab_command.LC_SYMTAB);
74 symtabCmd.putInt(symtab_command.cmdsize.off, symtab_command.totalsize);
75
76 symbolCount = 0;
77
78 }
79
80 public int getAlign() {
81 return (4);
82 }
83
84 public MachOSymbol addSymbolEntry(String name, byte type, byte secHdrIndex, long offset) {
85 // Get the current symbol index and append symbol name to string table.
86 int index;
87 MachOSymbol sym;
88
89 if (name.isEmpty()) {
90 index = 0;
91 strTabContent.append('\0');
92 strTabNrOfBytes += 1;
93 sym = new MachOSymbol(symbolCount, index, type, secHdrIndex, offset);
94 localSymbols.add(sym);
95 } else {
96 // We can't trust strTabContent.length() since that is
97 // chars (UTF16), keep track of bytes on our own.
98 index = strTabNrOfBytes;
99 strTabContent.append("_").append(name).append('\0');
100 // + 1 for null, + 1 for "_"
101 strTabNrOfBytes += (name.getBytes().length + 1 + 1);
102
103 sym = new MachOSymbol(symbolCount, index, type, secHdrIndex, offset);
104 switch (type) {
105 case nlist_64.N_EXT:
106 undefSymbols.add(sym);
107 break;
108 case nlist_64.N_SECT:
109 case nlist_64.N_UNDF: // null symbol
110 localSymbols.add(sym);
111 break;
112 case nlist_64.N_SECT|nlist_64.N_EXT:
113 globalSymbols.add(sym);
114 break;
115 default:
116 System.out.println("Unsupported Symbol type " + type);
117 break;
118 }
119 }
120 symbolCount++;
121 return (sym);
122 }
123
124 public void setOffset(int symoff) {
125 symtabCmd.putInt(symtab_command.symoff.off, symoff);
126 }
127
128 // Update the symbol indexes once all symbols have been added.
129 // This is required since we'll be reordering the symbols in the
130 // file to be in the order of Local, global and Undefined.
131 public void updateIndexes() {
132 int index = 0;
133
134 // Update the local symbol indexes
135 for (int i = 0; i < localSymbols.size(); i++ ) {
136 MachOSymbol sym = localSymbols.get(i);
137 sym.setIndex(index++);
138 }
139
140 // Update the global symbol indexes
141 for (int i = 0; i < globalSymbols.size(); i++ ) {
142 MachOSymbol sym = globalSymbols.get(i);
143 sym.setIndex(index++);
144 }
145
146 // Update the undefined symbol indexes
147 for (int i = index; i < undefSymbols.size(); i++ ) {
148 MachOSymbol sym = undefSymbols.get(i);
149 sym.setIndex(index++);
150 }
151 }
152
153 // Update LC_SYMTAB command fields based on the number of symbols added
154 // return the file size taken up by symbol table entries and strings
155 public int calcSizes() {
156 int stroff;
157
158 stroff = symtabCmd.getInt(symtab_command.symoff.off) + (nlist_64.totalsize * symbolCount);
159 symtabCmd.putInt(symtab_command.nsyms.off, symbolCount);
160 symtabCmd.putInt(symtab_command.stroff.off, stroff);
161 symtabCmd.putInt(symtab_command.strsize.off, strTabNrOfBytes);
162 symtabDataSize = (nlist_64.totalsize * symbolCount) + strTabNrOfBytes;
163
164 return (symtabDataSize);
165 }
166
167 public int getNumLocalSyms() { return localSymbols.size(); }
168 public int getNumGlobalSyms() { return globalSymbols.size(); }
169 public int getNumUndefSyms() { return undefSymbols.size(); }
170
171 public byte[] getCmdArray() {
172 return symtabCmd.array();
173 }
174
175 // Create a single byte array that contains the symbol table entries
176 // and string table
177 public byte[] getDataArray() {
178 int index = 0;
179 symtabData = MachOByteBuffer.allocate(symtabDataSize);
180 byte [] retarray;
181
182 // Add the local symbols
183 for (int i = 0; i < localSymbols.size(); i++ ) {
184 MachOSymbol sym = localSymbols.get(i);
185 byte [] arr = sym.getArray();
186 symtabData.put(arr);
187 }
188 // Add the global symbols
189 for (int i = 0; i < globalSymbols.size(); i++ ) {
190 MachOSymbol sym = globalSymbols.get(i);
191 byte [] arr = sym.getArray();
192 symtabData.put(arr);
193 }
194 // Add the undefined symbols
195 for (int i = 0; i < undefSymbols.size(); i++ ) {
196 MachOSymbol sym = undefSymbols.get(i);
197 byte [] arr = sym.getArray();
198 symtabData.put(arr);
199 }
200
201 // Add the stringtable
202 byte [] strs = strTabContent.toString().getBytes();
203 symtabData.put(strs);
204
205 retarray = symtabData.array();
206
207 return (retarray);
208 }
209 }
210
211