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      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 
     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   Expected<uint64_t> getSize() const;
     52 
     53   Expected<sys::fs::perms> getAccessMode() const;
     54   Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const;
     55 
     56   StringRef getRawLastModified() const {
     57     return StringRef(ArMemHdr->LastModified,
     58                      sizeof(ArMemHdr->LastModified)).rtrim(' ');
     59   }
     60 
     61   Expected<unsigned> getUID() const;
     62   Expected<unsigned> getGID() const;
     63 
     64   // This returns the size of the private struct ArMemHdrType
     65   uint64_t getSizeOf() const {
     66     return sizeof(ArMemHdrType);
     67   }
     68 
     69 private:
     70   struct ArMemHdrType {
     71     char Name[16];
     72     char LastModified[12];
     73     char UID[6];
     74     char GID[6];
     75     char AccessMode[8];
     76     char Size[10]; ///< Size of data, not including header or padding.
     77     char Terminator[2];
     78   };
     79   Archive const *Parent;
     80   ArMemHdrType const *ArMemHdr;
     81 };
     82 
     83 class Archive : public Binary {
     84   virtual void anchor();
     85 
     86 public:
     87   class Child {
     88     friend Archive;
     89     friend ArchiveMemberHeader;
     90 
     91     const Archive *Parent;
     92     ArchiveMemberHeader Header;
     93     /// Includes header but not padding byte.
     94     StringRef Data;
     95     /// Offset from Data to the start of the file.
     96     uint16_t StartOfFile;
     97 
     98     Expected<bool> isThinMember() const;
     99 
    100   public:
    101     Child(const Archive *Parent, const char *Start, Error *Err);
    102     Child(const Archive *Parent, StringRef Data, uint16_t StartOfFile);
    103 
    104     bool operator ==(const Child &other) const {
    105       assert(!Parent || !other.Parent || Parent == other.Parent);
    106       return Data.begin() == other.Data.begin();
    107     }
    108 
    109     const Archive *getParent() const { return Parent; }
    110     Expected<Child> getNext() const;
    111 
    112     Expected<StringRef> getName() const;
    113     Expected<std::string> getFullName() const;
    114     Expected<StringRef> getRawName() const { return Header.getRawName(); }
    115 
    116     Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const {
    117       return Header.getLastModified();
    118     }
    119 
    120     StringRef getRawLastModified() const {
    121       return Header.getRawLastModified();
    122     }
    123 
    124     Expected<unsigned> getUID() const { return Header.getUID(); }
    125     Expected<unsigned> getGID() const { return Header.getGID(); }
    126 
    127     Expected<sys::fs::perms> getAccessMode() const {
    128       return Header.getAccessMode();
    129     }
    130 
    131     /// \return the size of the archive member without the header or padding.
    132     Expected<uint64_t> getSize() const;
    133     /// \return the size in the archive header for this member.
    134     Expected<uint64_t> getRawSize() const;
    135 
    136     Expected<StringRef> getBuffer() const;
    137     uint64_t getChildOffset() const;
    138     uint64_t getDataOffset() const { return getChildOffset() + StartOfFile; }
    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   /// Size field is 10 decimal digits long
    225   static const uint64_t MaxMemberSize = 9999999999;
    226 
    227   enum Kind {
    228     K_GNU,
    229     K_GNU64,
    230     K_BSD,
    231     K_DARWIN,
    232     K_DARWIN64,
    233     K_COFF
    234   };
    235 
    236   Kind kind() const { return (Kind)Format; }
    237   bool isThin() const { return IsThin; }
    238 
    239   child_iterator child_begin(Error &Err, bool SkipInternal = true) const;
    240   child_iterator child_end() const;
    241   iterator_range<child_iterator> children(Error &Err,
    242                                           bool SkipInternal = true) const {
    243     return make_range(child_begin(Err, SkipInternal), child_end());
    244   }
    245 
    246   symbol_iterator symbol_begin() const;
    247   symbol_iterator symbol_end() const;
    248   iterator_range<symbol_iterator> symbols() const {
    249     return make_range(symbol_begin(), symbol_end());
    250   }
    251 
    252   // Cast methods.
    253   static bool classof(Binary const *v) {
    254     return v->isArchive();
    255   }
    256 
    257   // check if a symbol is in the archive
    258   Expected<Optional<Child>> findSym(StringRef name) const;
    259 
    260   bool isEmpty() const;
    261   bool hasSymbolTable() const;
    262   StringRef getSymbolTable() const { return SymbolTable; }
    263   StringRef getStringTable() const { return StringTable; }
    264   uint32_t getNumberOfSymbols() const;
    265 
    266   std::vector<std::unique_ptr<MemoryBuffer>> takeThinBuffers() {
    267     return std::move(ThinBuffers);
    268   }
    269 
    270 private:
    271   StringRef SymbolTable;
    272   StringRef StringTable;
    273 
    274   StringRef FirstRegularData;
    275   uint16_t FirstRegularStartOfFile = -1;
    276   void setFirstRegular(const Child &C);
    277 
    278   unsigned Format : 3;
    279   unsigned IsThin : 1;
    280   mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;
    281 };
    282 
    283 } // end namespace object
    284 } // end namespace llvm
    285 
    286 #endif // LLVM_OBJECT_ARCHIVE_H
    287