1 //===- Archive.h - ar archive file format -----------------------*- 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 declares the ar archive file format class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_OBJECT_ARCHIVE_H
15 #define LLVM_OBJECT_ARCHIVE_H
16 
17 #include "llvm/ADT/Optional.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/iterator_range.h"
20 #include "llvm/Object/Binary.h"
21 #include "llvm/Support/Chrono.h"
22 #include "llvm/Support/Error.h"
23 #include "llvm/Support/FileSystem.h"
24 #include "llvm/Support/MemoryBuffer.h"
25 #include <algorithm>
26 #include <cassert>
27 #include <cstdint>
28 #include <memory>
29 #include <string>
30 #include <vector>
31 
32 namespace llvm {
33 namespace object {
34 
35 class Archive;
36 
37 class ArchiveMemberHeader {
38 public:
39   friend class Archive;
40 
41   ArchiveMemberHeader(Archive const *Parent, const char *RawHeaderPtr,
42                       uint64_t Size, Error *Err);
43   // ArchiveMemberHeader() = default;
44 
45   /// Get the name without looking up long names.
46   Expected<StringRef> getRawName() const;
47 
48   /// Get the name looking up long names.
49   Expected<StringRef> getName(uint64_t Size) const;
50 
51   /// Members are not larger than 4GB.
52   Expected<uint32_t> getSize() const;
53 
54   Expected<sys::fs::perms> getAccessMode() const;
55   Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const;
56 
getRawLastModified()57   StringRef getRawLastModified() const {
58     return StringRef(ArMemHdr->LastModified,
59                      sizeof(ArMemHdr->LastModified)).rtrim(' ');
60   }
61 
62   Expected<unsigned> getUID() const;
63   Expected<unsigned> getGID() const;
64 
65   // This returns the size of the private struct ArMemHdrType
getSizeOf()66   uint64_t getSizeOf() const {
67     return sizeof(ArMemHdrType);
68   }
69 
70 private:
71   struct ArMemHdrType {
72     char Name[16];
73     char LastModified[12];
74     char UID[6];
75     char GID[6];
76     char AccessMode[8];
77     char Size[10]; ///< Size of data, not including header or padding.
78     char Terminator[2];
79   };
80   Archive const *Parent;
81   ArMemHdrType const *ArMemHdr;
82 };
83 
84 class Archive : public Binary {
85   virtual void anchor();
86 
87 public:
88   class Child {
89     friend Archive;
90     friend ArchiveMemberHeader;
91 
92     const Archive *Parent;
93     ArchiveMemberHeader Header;
94     /// Includes header but not padding byte.
95     StringRef Data;
96     /// Offset from Data to the start of the file.
97     uint16_t StartOfFile;
98 
99     Expected<bool> isThinMember() const;
100 
101   public:
102     Child(const Archive *Parent, const char *Start, Error *Err);
103     Child(const Archive *Parent, StringRef Data, uint16_t StartOfFile);
104 
105     bool operator ==(const Child &other) const {
106       assert(!Parent || !other.Parent || Parent == other.Parent);
107       return Data.begin() == other.Data.begin();
108     }
109 
getParent()110     const Archive *getParent() const { return Parent; }
111     Expected<Child> getNext() const;
112 
113     Expected<StringRef> getName() const;
114     Expected<std::string> getFullName() const;
getRawName()115     Expected<StringRef> getRawName() const { return Header.getRawName(); }
116 
getLastModified()117     Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const {
118       return Header.getLastModified();
119     }
120 
getRawLastModified()121     StringRef getRawLastModified() const {
122       return Header.getRawLastModified();
123     }
124 
getUID()125     Expected<unsigned> getUID() const { return Header.getUID(); }
getGID()126     Expected<unsigned> getGID() const { return Header.getGID(); }
127 
getAccessMode()128     Expected<sys::fs::perms> getAccessMode() const {
129       return Header.getAccessMode();
130     }
131 
132     /// \return the size of the archive member without the header or padding.
133     Expected<uint64_t> getSize() const;
134     /// \return the size in the archive header for this member.
135     Expected<uint64_t> getRawSize() const;
136 
137     Expected<StringRef> getBuffer() const;
138     uint64_t getChildOffset() const;
139 
140     Expected<MemoryBufferRef> getMemoryBufferRef() const;
141 
142     Expected<std::unique_ptr<Binary>>
143     getAsBinary(LLVMContext *Context = nullptr) const;
144   };
145 
146   class child_iterator {
147     Child C;
148     Error *E = nullptr;
149 
150   public:
child_iterator()151     child_iterator() : C(Child(nullptr, nullptr, nullptr)) {}
child_iterator(const Child & C,Error * E)152     child_iterator(const Child &C, Error *E) : C(C), E(E) {}
153 
154     const Child *operator->() const { return &C; }
155     const Child &operator*() const { return C; }
156 
157     bool operator==(const child_iterator &other) const {
158       // Ignore errors here: If an error occurred during increment then getNext
159       // will have been set to child_end(), and the following comparison should
160       // do the right thing.
161       return C == other.C;
162     }
163 
164     bool operator!=(const child_iterator &other) const {
165       return !(*this == other);
166     }
167 
168     // Code in loops with child_iterators must check for errors on each loop
169     // iteration.  And if there is an error break out of the loop.
170     child_iterator &operator++() { // Preincrement
171       assert(E && "Can't increment iterator with no Error attached");
172       ErrorAsOutParameter ErrAsOutParam(E);
173       if (auto ChildOrErr = C.getNext())
174         C = *ChildOrErr;
175       else {
176         C = C.getParent()->child_end().C;
177         *E = ChildOrErr.takeError();
178         E = nullptr;
179       }
180       return *this;
181     }
182   };
183 
184   class Symbol {
185     const Archive *Parent;
186     uint32_t SymbolIndex;
187     uint32_t StringIndex; // Extra index to the string.
188 
189   public:
Symbol(const Archive * p,uint32_t symi,uint32_t stri)190     Symbol(const Archive *p, uint32_t symi, uint32_t stri)
191       : Parent(p)
192       , SymbolIndex(symi)
193       , StringIndex(stri) {}
194 
195     bool operator ==(const Symbol &other) const {
196       return (Parent == other.Parent) && (SymbolIndex == other.SymbolIndex);
197     }
198 
199     StringRef getName() const;
200     Expected<Child> getMember() const;
201     Symbol getNext() const;
202   };
203 
204   class symbol_iterator {
205     Symbol symbol;
206 
207   public:
symbol_iterator(const Symbol & s)208     symbol_iterator(const Symbol &s) : symbol(s) {}
209 
210     const Symbol *operator->() const { return &symbol; }
211     const Symbol &operator*() const { return symbol; }
212 
213     bool operator==(const symbol_iterator &other) const {
214       return symbol == other.symbol;
215     }
216 
217     bool operator!=(const symbol_iterator &other) const {
218       return !(*this == other);
219     }
220 
221     symbol_iterator& operator++() {  // Preincrement
222       symbol = symbol.getNext();
223       return *this;
224     }
225   };
226 
227   Archive(MemoryBufferRef Source, Error &Err);
228   static Expected<std::unique_ptr<Archive>> create(MemoryBufferRef Source);
229 
230   enum Kind {
231     K_GNU,
232     K_GNU64,
233     K_BSD,
234     K_DARWIN,
235     K_DARWIN64,
236     K_COFF
237   };
238 
kind()239   Kind kind() const { return (Kind)Format; }
isThin()240   bool isThin() const { return IsThin; }
241 
242   child_iterator child_begin(Error &Err, bool SkipInternal = true) const;
243   child_iterator child_end() const;
244   iterator_range<child_iterator> children(Error &Err,
245                                           bool SkipInternal = true) const {
246     return make_range(child_begin(Err, SkipInternal), child_end());
247   }
248 
249   symbol_iterator symbol_begin() const;
250   symbol_iterator symbol_end() const;
symbols()251   iterator_range<symbol_iterator> symbols() const {
252     return make_range(symbol_begin(), symbol_end());
253   }
254 
255   // Cast methods.
classof(Binary const * v)256   static bool classof(Binary const *v) {
257     return v->isArchive();
258   }
259 
260   // check if a symbol is in the archive
261   Expected<Optional<Child>> findSym(StringRef name) const;
262 
263   bool isEmpty() const;
264   bool hasSymbolTable() const;
getSymbolTable()265   StringRef getSymbolTable() const { return SymbolTable; }
getStringTable()266   StringRef getStringTable() const { return StringTable; }
267   uint32_t getNumberOfSymbols() const;
268 
takeThinBuffers()269   std::vector<std::unique_ptr<MemoryBuffer>> takeThinBuffers() {
270     return std::move(ThinBuffers);
271   }
272 
273 private:
274   StringRef SymbolTable;
275   StringRef StringTable;
276 
277   StringRef FirstRegularData;
278   uint16_t FirstRegularStartOfFile = -1;
279   void setFirstRegular(const Child &C);
280 
281   unsigned Format : 3;
282   unsigned IsThin : 1;
283   mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;
284 };
285 
286 } // end namespace object
287 } // end namespace llvm
288 
289 #endif // LLVM_OBJECT_ARCHIVE_H
290