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