1 //===- Archive.cpp - ar File Format implementation --------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the ArchiveObjectFile class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/Object/Archive.h"
15 #include "llvm/ADT/APInt.h"
16 #include "llvm/Support/Endian.h"
17 #include "llvm/Support/MemoryBuffer.h"
18
19 using namespace llvm;
20 using namespace object;
21
22 static const char *Magic = "!<arch>\n";
23
isInternalMember(const ArchiveMemberHeader & amh)24 static bool isInternalMember(const ArchiveMemberHeader &amh) {
25 static const char *const internals[] = {
26 "/",
27 "//",
28 "#_LLVM_SYM_TAB_#"
29 };
30
31 StringRef name = amh.getName();
32 for (std::size_t i = 0; i < sizeof(internals) / sizeof(*internals); ++i) {
33 if (name == internals[i])
34 return true;
35 }
36 return false;
37 }
38
anchor()39 void Archive::anchor() { }
40
getName(StringRef & Result) const41 error_code Archive::Child::getName(StringRef &Result) const {
42 StringRef name = ToHeader(Data.data())->getName();
43 // Check if it's a special name.
44 if (name[0] == '/') {
45 if (name.size() == 1) { // Linker member.
46 Result = name;
47 return object_error::success;
48 }
49 if (name.size() == 2 && name[1] == '/') { // String table.
50 Result = name;
51 return object_error::success;
52 }
53 // It's a long name.
54 // Get the offset.
55 std::size_t offset;
56 if (name.substr(1).rtrim(" ").getAsInteger(10, offset))
57 llvm_unreachable("Long name offset is not an integer");
58 const char *addr = Parent->StringTable->Data.begin()
59 + sizeof(ArchiveMemberHeader)
60 + offset;
61 // Verify it.
62 if (Parent->StringTable == Parent->end_children()
63 || addr < (Parent->StringTable->Data.begin()
64 + sizeof(ArchiveMemberHeader))
65 || addr > (Parent->StringTable->Data.begin()
66 + sizeof(ArchiveMemberHeader)
67 + Parent->StringTable->getSize()))
68 return object_error::parse_failed;
69
70 // GNU long file names end with a /.
71 if (Parent->kind() == K_GNU) {
72 StringRef::size_type End = StringRef(addr).find('/');
73 Result = StringRef(addr, End);
74 } else {
75 Result = addr;
76 }
77 return object_error::success;
78 } else if (name.startswith("#1/")) {
79 uint64_t name_size;
80 if (name.substr(3).rtrim(" ").getAsInteger(10, name_size))
81 llvm_unreachable("Long name length is not an ingeter");
82 Result = Data.substr(sizeof(ArchiveMemberHeader), name_size);
83 return object_error::success;
84 }
85 // It's a simple name.
86 if (name[name.size() - 1] == '/')
87 Result = name.substr(0, name.size() - 1);
88 else
89 Result = name;
90 return object_error::success;
91 }
92
getAsBinary(OwningPtr<Binary> & Result) const93 error_code Archive::Child::getAsBinary(OwningPtr<Binary> &Result) const {
94 OwningPtr<Binary> ret;
95 OwningPtr<MemoryBuffer> Buff;
96 if (error_code ec = getMemoryBuffer(Buff))
97 return ec;
98 if (error_code ec = createBinary(Buff.take(), ret))
99 return ec;
100 Result.swap(ret);
101 return object_error::success;
102 }
103
Archive(MemoryBuffer * source,error_code & ec)104 Archive::Archive(MemoryBuffer *source, error_code &ec)
105 : Binary(Binary::ID_Archive, source) {
106 // Check for sufficient magic.
107 if (!source || source->getBufferSize()
108 < (8 + sizeof(ArchiveMemberHeader) + 2) // Smallest archive.
109 || StringRef(source->getBufferStart(), 8) != Magic) {
110 ec = object_error::invalid_file_type;
111 return;
112 }
113
114 // Get the special members.
115 child_iterator i = begin_children(false);
116 child_iterator e = end_children();
117
118 StringRef name;
119 if ((ec = i->getName(name)))
120 return;
121
122 // Below is the pattern that is used to figure out the archive format
123 // GNU archive format
124 // First member : / (points to the symbol table )
125 // Second member : // (may exist, if it exists, points to the string table)
126 // Note : The string table is used if the filename exceeds 15 characters
127 // BSD archive format
128 // First member : __.SYMDEF (points to the symbol table)
129 // There is no string table, if the filename exceeds 15 characters or has a
130 // embedded space, the filename has #1/<size>, The size represents the size
131 // of the filename that needs to be read after the archive header
132 // COFF archive format
133 // First member : /
134 // Second member : / (provides a directory of symbols)
135 // Third member : // contains the string table, this is present even if the
136 // string table is empty
137 if (name == "/") {
138 SymbolTable = i;
139 StringTable = e;
140 if (i != e) ++i;
141 if (i == e) {
142 ec = object_error::parse_failed;
143 return;
144 }
145 if ((ec = i->getName(name)))
146 return;
147 if (name[0] != '/') {
148 Format = K_GNU;
149 } else if ((name.size() > 1) && (name == "//")) {
150 Format = K_GNU;
151 StringTable = i;
152 ++i;
153 } else {
154 Format = K_COFF;
155 if (i != e) {
156 SymbolTable = i;
157 ++i;
158 }
159 if (i != e) {
160 StringTable = i;
161 }
162 }
163 } else if (name == "__.SYMDEF") {
164 Format = K_BSD;
165 SymbolTable = i;
166 StringTable = e;
167 }
168 ec = object_error::success;
169 }
170
begin_children(bool skip_internal) const171 Archive::child_iterator Archive::begin_children(bool skip_internal) const {
172 const char *Loc = Data->getBufferStart() + strlen(Magic);
173 size_t Size = sizeof(ArchiveMemberHeader) +
174 ToHeader(Loc)->getSize();
175 Child c(this, StringRef(Loc, Size));
176 // Skip internals at the beginning of an archive.
177 if (skip_internal && isInternalMember(*ToHeader(Loc)))
178 return c.getNext();
179 return c;
180 }
181
end_children() const182 Archive::child_iterator Archive::end_children() const {
183 return Child(this, StringRef(0, 0));
184 }
185
getName(StringRef & Result) const186 error_code Archive::Symbol::getName(StringRef &Result) const {
187 Result = StringRef(Parent->SymbolTable->getBuffer().begin() + StringIndex);
188 return object_error::success;
189 }
190
getMember(child_iterator & Result) const191 error_code Archive::Symbol::getMember(child_iterator &Result) const {
192 const char *Buf = Parent->SymbolTable->getBuffer().begin();
193 const char *Offsets = Buf + 4;
194 uint32_t Offset = 0;
195 if (Parent->kind() == K_GNU) {
196 Offset = *(reinterpret_cast<const support::ubig32_t*>(Offsets)
197 + SymbolIndex);
198 } else if (Parent->kind() == K_BSD) {
199 llvm_unreachable("BSD format is not supported");
200 } else {
201 uint32_t MemberCount = *reinterpret_cast<const support::ulittle32_t*>(Buf);
202
203 // Skip offsets.
204 Buf += sizeof(support::ulittle32_t)
205 + (MemberCount * sizeof(support::ulittle32_t));
206
207 uint32_t SymbolCount = *reinterpret_cast<const support::ulittle32_t*>(Buf);
208
209 if (SymbolIndex >= SymbolCount)
210 return object_error::parse_failed;
211
212 // Skip SymbolCount to get to the indices table.
213 const char *Indices = Buf + sizeof(support::ulittle32_t);
214
215 // Get the index of the offset in the file member offset table for this
216 // symbol.
217 uint16_t OffsetIndex =
218 *(reinterpret_cast<const support::ulittle16_t*>(Indices)
219 + SymbolIndex);
220 // Subtract 1 since OffsetIndex is 1 based.
221 --OffsetIndex;
222
223 if (OffsetIndex >= MemberCount)
224 return object_error::parse_failed;
225
226 Offset = *(reinterpret_cast<const support::ulittle32_t*>(Offsets)
227 + OffsetIndex);
228 }
229
230 const char *Loc = Parent->getData().begin() + Offset;
231 size_t Size = sizeof(ArchiveMemberHeader) +
232 ToHeader(Loc)->getSize();
233 Result = Child(Parent, StringRef(Loc, Size));
234
235 return object_error::success;
236 }
237
getNext() const238 Archive::Symbol Archive::Symbol::getNext() const {
239 Symbol t(*this);
240 // Go to one past next null.
241 t.StringIndex =
242 Parent->SymbolTable->getBuffer().find('\0', t.StringIndex) + 1;
243 ++t.SymbolIndex;
244 return t;
245 }
246
begin_symbols() const247 Archive::symbol_iterator Archive::begin_symbols() const {
248 const char *buf = SymbolTable->getBuffer().begin();
249 if (kind() == K_GNU) {
250 uint32_t symbol_count = 0;
251 symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
252 buf += sizeof(uint32_t) + (symbol_count * (sizeof(uint32_t)));
253 } else if (kind() == K_BSD) {
254 llvm_unreachable("BSD archive format is not supported");
255 } else {
256 uint32_t member_count = 0;
257 uint32_t symbol_count = 0;
258 member_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
259 buf += 4 + (member_count * 4); // Skip offsets.
260 symbol_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
261 buf += 4 + (symbol_count * 2); // Skip indices.
262 }
263 uint32_t string_start_offset = buf - SymbolTable->getBuffer().begin();
264 return symbol_iterator(Symbol(this, 0, string_start_offset));
265 }
266
end_symbols() const267 Archive::symbol_iterator Archive::end_symbols() const {
268 const char *buf = SymbolTable->getBuffer().begin();
269 uint32_t symbol_count = 0;
270 if (kind() == K_GNU) {
271 symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
272 buf += sizeof(uint32_t) + (symbol_count * (sizeof(uint32_t)));
273 } else if (kind() == K_BSD) {
274 llvm_unreachable("BSD archive format is not supported");
275 } else {
276 uint32_t member_count = 0;
277 member_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
278 buf += 4 + (member_count * 4); // Skip offsets.
279 symbol_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
280 }
281 return symbol_iterator(
282 Symbol(this, symbol_count, 0));
283 }
284
findSym(StringRef name) const285 Archive::child_iterator Archive::findSym(StringRef name) const {
286 Archive::symbol_iterator bs = begin_symbols();
287 Archive::symbol_iterator es = end_symbols();
288 Archive::child_iterator result;
289
290 StringRef symname;
291 for (; bs != es; ++bs) {
292 if (bs->getName(symname))
293 return end_children();
294 if (symname == name) {
295 if (bs->getMember(result))
296 return end_children();
297 return result;
298 }
299 }
300 return end_children();
301 }
302