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/StringRef.h"
17#include "llvm/ADT/fallible_iterator.h"
18#include "llvm/ADT/iterator_range.h"
19#include "llvm/Object/Binary.h"
20#include "llvm/Support/Chrono.h"
21#include "llvm/Support/Error.h"
22#include "llvm/Support/FileSystem.h"
23#include "llvm/Support/MemoryBuffer.h"
24#include <cassert>
25#include <cstdint>
26#include <memory>
27#include <string>
28#include <vector>
29
30namespace llvm {
31namespace object {
32
33const char ArchiveMagic[] = "!<arch>\n";
34const char ThinArchiveMagic[] = "!<thin>\n";
35const char BigArchiveMagic[] = "<bigaf>\n";
36
37class Archive;
38
39class AbstractArchiveMemberHeader {
40protected:
41  AbstractArchiveMemberHeader(const Archive *Parent) : Parent(Parent){};
42
43public:
44  friend class Archive;
45  virtual std::unique_ptr<AbstractArchiveMemberHeader> clone() const = 0;
46  virtual ~AbstractArchiveMemberHeader() = default;
47
48  /// Get the name without looking up long names.
49  virtual Expected<StringRef> getRawName() const = 0;
50  virtual StringRef getRawAccessMode() const = 0;
51  virtual StringRef getRawLastModified() const = 0;
52  virtual StringRef getRawUID() const = 0;
53  virtual StringRef getRawGID() const = 0;
54
55  /// Get the name looking up long names.
56  virtual Expected<StringRef> getName(uint64_t Size) const = 0;
57  virtual Expected<uint64_t> getSize() const = 0;
58  virtual uint64_t getOffset() const = 0;
59
60  /// Get next file member location.
61  virtual Expected<const char *> getNextChildLoc() const = 0;
62  virtual Expected<bool> isThin() const = 0;
63
64  Expected<sys::fs::perms> getAccessMode() const;
65  Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const;
66  Expected<unsigned> getUID() const;
67  Expected<unsigned> getGID() const;
68
69  /// Returns the size in bytes of the format-defined member header of the
70  /// concrete archive type.
71  virtual uint64_t getSizeOf() const = 0;
72
73  const Archive *Parent;
74};
75
76template <typename T>
77class CommonArchiveMemberHeader : public AbstractArchiveMemberHeader {
78public:
79  CommonArchiveMemberHeader(const Archive *Parent, const T *RawHeaderPtr)
80      : AbstractArchiveMemberHeader(Parent), ArMemHdr(RawHeaderPtr){};
81  StringRef getRawAccessMode() const override;
82  StringRef getRawLastModified() const override;
83  StringRef getRawUID() const override;
84  StringRef getRawGID() const override;
85
86  uint64_t getOffset() const override;
87  uint64_t getSizeOf() const override { return sizeof(T); }
88
89  T const *ArMemHdr;
90};
91
92struct UnixArMemHdrType {
93  char Name[16];
94  char LastModified[12];
95  char UID[6];
96  char GID[6];
97  char AccessMode[8];
98  char Size[10]; ///< Size of data, not including header or padding.
99  char Terminator[2];
100};
101
102class ArchiveMemberHeader : public CommonArchiveMemberHeader<UnixArMemHdrType> {
103public:
104  ArchiveMemberHeader(const Archive *Parent, const char *RawHeaderPtr,
105                      uint64_t Size, Error *Err);
106
107  std::unique_ptr<AbstractArchiveMemberHeader> clone() const override {
108    return std::make_unique<ArchiveMemberHeader>(*this);
109  }
110
111  Expected<StringRef> getRawName() const override;
112
113  Expected<StringRef> getName(uint64_t Size) const override;
114  Expected<uint64_t> getSize() const override;
115  Expected<const char *> getNextChildLoc() const override;
116  Expected<bool> isThin() const override;
117};
118
119// File Member Header
120struct BigArMemHdrType {
121  char Size[20];       // File member size in decimal
122  char NextOffset[20]; // Next member offset in decimal
123  char PrevOffset[20]; // Previous member offset in decimal
124  char LastModified[12];
125  char UID[12];
126  char GID[12];
127  char AccessMode[12];
128  char NameLen[4]; // File member name length in decimal
129  union {
130    char Name[2]; // Start of member name
131    char Terminator[2];
132  };
133};
134
135// Define file member header of AIX big archive.
136class BigArchiveMemberHeader
137    : public CommonArchiveMemberHeader<BigArMemHdrType> {
138
139public:
140  BigArchiveMemberHeader(Archive const *Parent, const char *RawHeaderPtr,
141                         uint64_t Size, Error *Err);
142  std::unique_ptr<AbstractArchiveMemberHeader> clone() const override {
143    return std::make_unique<BigArchiveMemberHeader>(*this);
144  }
145
146  Expected<StringRef> getRawName() const override;
147  Expected<uint64_t> getRawNameSize() const;
148
149  Expected<StringRef> getName(uint64_t Size) const override;
150  Expected<uint64_t> getSize() const override;
151  Expected<const char *> getNextChildLoc() const override;
152  Expected<uint64_t> getNextOffset() const;
153  Expected<bool> isThin() const override { return false; }
154};
155
156class Archive : public Binary {
157  virtual void anchor();
158
159public:
160  class Child {
161    friend Archive;
162    friend AbstractArchiveMemberHeader;
163
164    const Archive *Parent;
165    std::unique_ptr<AbstractArchiveMemberHeader> Header;
166    /// Includes header but not padding byte.
167    StringRef Data;
168    /// Offset from Data to the start of the file.
169    uint16_t StartOfFile;
170
171    Expected<bool> isThinMember() const;
172
173  public:
174    Child(const Archive *Parent, const char *Start, Error *Err);
175    Child(const Archive *Parent, StringRef Data, uint16_t StartOfFile);
176
177    Child(const Child &C)
178        : Parent(C.Parent), Data(C.Data), StartOfFile(C.StartOfFile) {
179      if (C.Header)
180        Header = C.Header->clone();
181    }
182
183    Child(Child &&C) {
184      Parent = std::move(C.Parent);
185      Header = std::move(C.Header);
186      Data = C.Data;
187      StartOfFile = C.StartOfFile;
188    }
189
190    Child &operator=(Child &&C) noexcept {
191      if (&C == this)
192        return *this;
193
194      Parent = std::move(C.Parent);
195      Header = std::move(C.Header);
196      Data = C.Data;
197      StartOfFile = C.StartOfFile;
198
199      return *this;
200    }
201
202    Child &operator=(const Child &C) {
203      if (&C == this)
204        return *this;
205
206      Parent = C.Parent;
207      if (C.Header)
208        Header = C.Header->clone();
209      Data = C.Data;
210      StartOfFile = C.StartOfFile;
211
212      return *this;
213    }
214
215    bool operator==(const Child &other) const {
216      assert(!Parent || !other.Parent || Parent == other.Parent);
217      return Data.begin() == other.Data.begin();
218    }
219
220    const Archive *getParent() const { return Parent; }
221    Expected<Child> getNext() const;
222
223    Expected<StringRef> getName() const;
224    Expected<std::string> getFullName() const;
225    Expected<StringRef> getRawName() const { return Header->getRawName(); }
226
227    Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const {
228      return Header->getLastModified();
229    }
230
231    StringRef getRawLastModified() const {
232      return Header->getRawLastModified();
233    }
234
235    Expected<unsigned> getUID() const { return Header->getUID(); }
236    Expected<unsigned> getGID() const { return Header->getGID(); }
237
238    Expected<sys::fs::perms> getAccessMode() const {
239      return Header->getAccessMode();
240    }
241
242    /// \return the size of the archive member without the header or padding.
243    Expected<uint64_t> getSize() const;
244    /// \return the size in the archive header for this member.
245    Expected<uint64_t> getRawSize() const;
246
247    Expected<StringRef> getBuffer() const;
248    uint64_t getChildOffset() const;
249    uint64_t getDataOffset() const { return getChildOffset() + StartOfFile; }
250
251    Expected<MemoryBufferRef> getMemoryBufferRef() const;
252
253    Expected<std::unique_ptr<Binary>>
254    getAsBinary(LLVMContext *Context = nullptr) const;
255  };
256
257  class ChildFallibleIterator {
258    Child C;
259
260  public:
261    ChildFallibleIterator() : C(Child(nullptr, nullptr, nullptr)) {}
262    ChildFallibleIterator(const Child &C) : C(C) {}
263
264    const Child *operator->() const { return &C; }
265    const Child &operator*() const { return C; }
266
267    bool operator==(const ChildFallibleIterator &other) const {
268      // Ignore errors here: If an error occurred during increment then getNext
269      // will have been set to child_end(), and the following comparison should
270      // do the right thing.
271      return C == other.C;
272    }
273
274    bool operator!=(const ChildFallibleIterator &other) const {
275      return !(*this == other);
276    }
277
278    Error inc() {
279      auto NextChild = C.getNext();
280      if (!NextChild)
281        return NextChild.takeError();
282      C = std::move(*NextChild);
283      return Error::success();
284    }
285  };
286
287  using child_iterator = fallible_iterator<ChildFallibleIterator>;
288
289  class Symbol {
290    const Archive *Parent;
291    uint32_t SymbolIndex;
292    uint32_t StringIndex; // Extra index to the string.
293
294  public:
295    Symbol(const Archive *p, uint32_t symi, uint32_t stri)
296        : Parent(p), SymbolIndex(symi), StringIndex(stri) {}
297
298    bool operator==(const Symbol &other) const {
299      return (Parent == other.Parent) && (SymbolIndex == other.SymbolIndex);
300    }
301
302    StringRef getName() const;
303    Expected<Child> getMember() const;
304    Symbol getNext() const;
305    bool isECSymbol() const;
306  };
307
308  class symbol_iterator {
309    Symbol symbol;
310
311  public:
312    symbol_iterator(const Symbol &s) : symbol(s) {}
313
314    const Symbol *operator->() const { return &symbol; }
315    const Symbol &operator*() const { return symbol; }
316
317    bool operator==(const symbol_iterator &other) const {
318      return symbol == other.symbol;
319    }
320
321    bool operator!=(const symbol_iterator &other) const {
322      return !(*this == other);
323    }
324
325    symbol_iterator &operator++() { // Preincrement
326      symbol = symbol.getNext();
327      return *this;
328    }
329  };
330
331  Archive(MemoryBufferRef Source, Error &Err);
332  static Expected<std::unique_ptr<Archive>> create(MemoryBufferRef Source);
333
334  /// Size field is 10 decimal digits long
335  static const uint64_t MaxMemberSize = 9999999999;
336
337  enum Kind { K_GNU, K_GNU64, K_BSD, K_DARWIN, K_DARWIN64, K_COFF, K_AIXBIG };
338
339  Kind kind() const { return (Kind)Format; }
340  bool isThin() const { return IsThin; }
341  static object::Archive::Kind getDefaultKindForHost();
342
343  child_iterator child_begin(Error &Err, bool SkipInternal = true) const;
344  child_iterator child_end() const;
345  iterator_range<child_iterator> children(Error &Err,
346                                          bool SkipInternal = true) const {
347    return make_range(child_begin(Err, SkipInternal), child_end());
348  }
349
350  symbol_iterator symbol_begin() const;
351  symbol_iterator symbol_end() const;
352  iterator_range<symbol_iterator> symbols() const {
353    return make_range(symbol_begin(), symbol_end());
354  }
355
356  Expected<iterator_range<symbol_iterator>> ec_symbols() const;
357
358  static bool classof(Binary const *v) { return v->isArchive(); }
359
360  // check if a symbol is in the archive
361  Expected<std::optional<Child>> findSym(StringRef name) const;
362
363  virtual bool isEmpty() const;
364  bool hasSymbolTable() const;
365  StringRef getSymbolTable() const { return SymbolTable; }
366  StringRef getStringTable() const { return StringTable; }
367  uint32_t getNumberOfSymbols() const;
368  uint32_t getNumberOfECSymbols() const;
369  virtual uint64_t getFirstChildOffset() const { return getArchiveMagicLen(); }
370
371  std::vector<std::unique_ptr<MemoryBuffer>> takeThinBuffers() {
372    return std::move(ThinBuffers);
373  }
374
375  std::unique_ptr<AbstractArchiveMemberHeader>
376  createArchiveMemberHeader(const char *RawHeaderPtr, uint64_t Size,
377                            Error *Err) const;
378
379protected:
380  uint64_t getArchiveMagicLen() const;
381  void setFirstRegular(const Child &C);
382
383  StringRef SymbolTable;
384  StringRef ECSymbolTable;
385  StringRef StringTable;
386
387private:
388  StringRef FirstRegularData;
389  uint16_t FirstRegularStartOfFile = -1;
390
391  unsigned Format : 3;
392  unsigned IsThin : 1;
393  mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;
394};
395
396class BigArchive : public Archive {
397public:
398  /// Fixed-Length Header.
399  struct FixLenHdr {
400    char Magic[sizeof(BigArchiveMagic) - 1]; ///< Big archive magic string.
401    char MemOffset[20];                      ///< Offset to member table.
402    char GlobSymOffset[20];                  ///< Offset to global symbol table.
403    char
404        GlobSym64Offset[20]; ///< Offset global symbol table for 64-bit objects.
405    char FirstChildOffset[20]; ///< Offset to first archive member.
406    char LastChildOffset[20];  ///< Offset to last archive member.
407    char FreeOffset[20];       ///< Offset to first mem on free list.
408  };
409
410  const FixLenHdr *ArFixLenHdr;
411  uint64_t FirstChildOffset = 0;
412  uint64_t LastChildOffset = 0;
413  std::string MergedGlobalSymtabBuf;
414  bool Has32BitGlobalSymtab = false;
415  bool Has64BitGlobalSymtab = false;
416
417public:
418  BigArchive(MemoryBufferRef Source, Error &Err);
419  uint64_t getFirstChildOffset() const override { return FirstChildOffset; }
420  uint64_t getLastChildOffset() const { return LastChildOffset; }
421  bool isEmpty() const override { return getFirstChildOffset() == 0; }
422
423  bool has32BitGlobalSymtab() { return Has32BitGlobalSymtab; }
424  bool has64BitGlobalSymtab() { return Has64BitGlobalSymtab; }
425};
426
427} // end namespace object
428} // end namespace llvm
429
430#endif // LLVM_OBJECT_ARCHIVE_H
431