Archive.h revision d111c7844ec26448764ced627e153f406d730c5f
1//===- Archive.h - ar archive file format -----------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file declares the ar archive file format class.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_OBJECT_ARCHIVE_H
14#define LLVM_OBJECT_ARCHIVE_H
15
16#include "llvm/ADT/Optional.h"
17#include "llvm/ADT/StringRef.h"
18#include "llvm/ADT/fallible_iterator.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
32namespace llvm {
33namespace object {
34
35class Archive;
36
37class ArchiveMemberHeader {
38public:
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
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
66  uint64_t getSizeOf() const {
67    return sizeof(ArMemHdrType);
68  }
69
70private:
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
84class Archive : public Binary {
85  virtual void anchor();
86
87public:
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
110    const Archive *getParent() const { return Parent; }
111    Expected<Child> getNext() const;
112
113    Expected<StringRef> getName() const;
114    Expected<std::string> getFullName() const;
115    Expected<StringRef> getRawName() const { return Header.getRawName(); }
116
117    Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const {
118      return Header.getLastModified();
119    }
120
121    StringRef getRawLastModified() const {
122      return Header.getRawLastModified();
123    }
124
125    Expected<unsigned> getUID() const { return Header.getUID(); }
126    Expected<unsigned> getGID() const { return Header.getGID(); }
127
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 ChildFallibleIterator {
147    Child C;
148
149  public:
150    ChildFallibleIterator() : C(Child(nullptr, nullptr, nullptr)) {}
151    ChildFallibleIterator(const Child &C) : C(C) {}
152
153    const Child *operator->() const { return &C; }
154    const Child &operator*() const { return C; }
155
156    bool operator==(const ChildFallibleIterator &other) const {
157      // Ignore errors here: If an error occurred during increment then getNext
158      // will have been set to child_end(), and the following comparison should
159      // do the right thing.
160      return C == other.C;
161    }
162
163    bool operator!=(const ChildFallibleIterator &other) const {
164      return !(*this == other);
165    }
166
167    Error inc() {
168      auto NextChild = C.getNext();
169      if (!NextChild)
170        return NextChild.takeError();
171      C = std::move(*NextChild);
172      return Error::success();
173    }
174  };
175
176  using child_iterator = fallible_iterator<ChildFallibleIterator>;
177
178  class Symbol {
179    const Archive *Parent;
180    uint32_t SymbolIndex;
181    uint32_t StringIndex; // Extra index to the string.
182
183  public:
184    Symbol(const Archive *p, uint32_t symi, uint32_t stri)
185      : Parent(p)
186      , SymbolIndex(symi)
187      , StringIndex(stri) {}
188
189    bool operator ==(const Symbol &other) const {
190      return (Parent == other.Parent) && (SymbolIndex == other.SymbolIndex);
191    }
192
193    StringRef getName() const;
194    Expected<Child> getMember() const;
195    Symbol getNext() const;
196  };
197
198  class symbol_iterator {
199    Symbol symbol;
200
201  public:
202    symbol_iterator(const Symbol &s) : symbol(s) {}
203
204    const Symbol *operator->() const { return &symbol; }
205    const Symbol &operator*() const { return symbol; }
206
207    bool operator==(const symbol_iterator &other) const {
208      return symbol == other.symbol;
209    }
210
211    bool operator!=(const symbol_iterator &other) const {
212      return !(*this == other);
213    }
214
215    symbol_iterator& operator++() {  // Preincrement
216      symbol = symbol.getNext();
217      return *this;
218    }
219  };
220
221  Archive(MemoryBufferRef Source, Error &Err);
222  static Expected<std::unique_ptr<Archive>> create(MemoryBufferRef Source);
223
224  enum Kind {
225    K_GNU,
226    K_GNU64,
227    K_BSD,
228    K_DARWIN,
229    K_DARWIN64,
230    K_COFF
231  };
232
233  Kind kind() const { return (Kind)Format; }
234  bool isThin() const { return IsThin; }
235
236  child_iterator child_begin(Error &Err, bool SkipInternal = true) const;
237  child_iterator child_end() const;
238  iterator_range<child_iterator> children(Error &Err,
239                                          bool SkipInternal = true) const {
240    return make_range(child_begin(Err, SkipInternal), child_end());
241  }
242
243  symbol_iterator symbol_begin() const;
244  symbol_iterator symbol_end() const;
245  iterator_range<symbol_iterator> symbols() const {
246    return make_range(symbol_begin(), symbol_end());
247  }
248
249  // Cast methods.
250  static bool classof(Binary const *v) {
251    return v->isArchive();
252  }
253
254  // check if a symbol is in the archive
255  Expected<Optional<Child>> findSym(StringRef name) const;
256
257  bool isEmpty() const;
258  bool hasSymbolTable() const;
259  StringRef getSymbolTable() const { return SymbolTable; }
260  StringRef getStringTable() const { return StringTable; }
261  uint32_t getNumberOfSymbols() const;
262
263  std::vector<std::unique_ptr<MemoryBuffer>> takeThinBuffers() {
264    return std::move(ThinBuffers);
265  }
266
267private:
268  StringRef SymbolTable;
269  StringRef StringTable;
270
271  StringRef FirstRegularData;
272  uint16_t FirstRegularStartOfFile = -1;
273  void setFirstRegular(const Child &C);
274
275  unsigned Format : 3;
276  unsigned IsThin : 1;
277  mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;
278};
279
280} // end namespace object
281} // end namespace llvm
282
283#endif // LLVM_OBJECT_ARCHIVE_H
284