1 /*
2 * Copyright (c) 2017, 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
26 package jdk.tools.jaotc.binformat.macho;
27
28 import java.nio.ByteBuffer;
29 import java.util.ArrayList;
30
31 import jdk.tools.jaotc.binformat.macho.MachO.nlist_64;
32 import jdk.tools.jaotc.binformat.macho.MachO.symtab_command;
33
34 final class MachOSymtab {
35
36 /**
37 * ByteBuffer holding the LC_SYMTAB command contents.
38 */
39 private final ByteBuffer symtabCmd;
40
41 private int symtabDataSize;
42
43 private final ArrayList<MachOSymbol> localSymbols = new ArrayList<>();
44 private final ArrayList<MachOSymbol> globalSymbols = new ArrayList<>();
45 private final ArrayList<MachOSymbol> undefSymbols = new ArrayList<>();
46
47 /**
48 * Number of symbols added.
49 */
50 private int symbolCount;
51
52 /**
53 * String holding symbol table strings.
54 */
55 private final StringBuilder strTabContent = new StringBuilder();
56
57 /**
58 * Keeps track of bytes in string table since strTabContent.length() is number of chars, not
59 * bytes.
60 */
61 private int strTabNrOfBytes = 0;
62
63 MachOSymtab() {
64 symtabCmd = MachOByteBuffer.allocate(symtab_command.totalsize);
65
66 symtabCmd.putInt(symtab_command.cmd.off, symtab_command.LC_SYMTAB);
67 symtabCmd.putInt(symtab_command.cmdsize.off, symtab_command.totalsize);
68
69 symbolCount = 0;
70
71 }
72
73 static int getAlign() {
74 return (4);
75 }
76
77 MachOSymbol addSymbolEntry(String name, byte type, byte secHdrIndex, long offset) {
78 // Get the current symbol index and append symbol name to string table.
79 int index;
80 MachOSymbol sym;
81
82 if (name.isEmpty()) {
83 index = 0;
84 strTabContent.append('\0');
85 strTabNrOfBytes += 1;
86 sym = new MachOSymbol(symbolCount, index, type, secHdrIndex, offset);
87 localSymbols.add(sym);
88 } else {
89 // We can't trust strTabContent.length() since that is
90 // chars (UTF16), keep track of bytes on our own.
91 index = strTabNrOfBytes;
92 strTabContent.append("_").append(name).append('\0');
93 // + 1 for null, + 1 for "_"
94 strTabNrOfBytes += (name.getBytes().length + 1 + 1);
95
96 sym = new MachOSymbol(symbolCount, index, type, secHdrIndex, offset);
97 switch (type) {
98 case nlist_64.N_EXT:
99 undefSymbols.add(sym);
100 break;
101 case nlist_64.N_SECT:
102 case nlist_64.N_UNDF: // null symbol
103 localSymbols.add(sym);
104 break;
105 case nlist_64.N_SECT | nlist_64.N_EXT:
106 globalSymbols.add(sym);
107 break;
108 default:
109 System.out.println("Unsupported Symbol type " + type);
110 break;
111 }
112 }
113 symbolCount++;
114 return (sym);
115 }
116
117 void setOffset(int symoff) {
118 symtabCmd.putInt(symtab_command.symoff.off, symoff);
119 }
120
121 // Update the symbol indexes once all symbols have been added.
122 // This is required since we'll be reordering the symbols in the
123 // file to be in the order of Local, global and Undefined.
124 void updateIndexes() {
125 int index = 0;
126
127 // Update the local symbol indexes
128 for (int i = 0; i < localSymbols.size(); i++) {
129 MachOSymbol sym = localSymbols.get(i);
130 sym.setIndex(index++);
131 }
132
133 // Update the global symbol indexes
134 for (int i = 0; i < globalSymbols.size(); i++) {
135 MachOSymbol sym = globalSymbols.get(i);
136 sym.setIndex(index++);
137 }
138
139 // Update the undefined symbol indexes
140 for (int i = index; i < undefSymbols.size(); i++) {
141 MachOSymbol sym = undefSymbols.get(i);
142 sym.setIndex(index++);
143 }
144 }
145
146 // Update LC_SYMTAB command fields based on the number of symbols added
147 // return the file size taken up by symbol table entries and strings
148 int calcSizes() {
149 int stroff;
150
151 stroff = symtabCmd.getInt(symtab_command.symoff.off) + (nlist_64.totalsize * symbolCount);
152 symtabCmd.putInt(symtab_command.nsyms.off, symbolCount);
153 symtabCmd.putInt(symtab_command.stroff.off, stroff);
154 symtabCmd.putInt(symtab_command.strsize.off, strTabNrOfBytes);
155 symtabDataSize = (nlist_64.totalsize * symbolCount) + strTabNrOfBytes;
156
157 return (symtabDataSize);
158 }
159
160 int getNumLocalSyms() {
161 return localSymbols.size();
162 }
163
164 int getNumGlobalSyms() {
165 return globalSymbols.size();
166 }
167
168 int getNumUndefSyms() {
169 return undefSymbols.size();
170 }
171
172 byte[] getCmdArray() {
173 return symtabCmd.array();
174 }
175
176 // Create a single byte array that contains the symbol table entries
177 // and string table
178 byte[] getDataArray() {
179 ByteBuffer 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 }