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/MemoryBuffer.h" 17 18 using namespace llvm; 19 using namespace object; 20 21 namespace { 22 const StringRef Magic = "!<arch>\n"; 23 24 struct ArchiveMemberHeader { 25 char Name[16]; 26 char LastModified[12]; 27 char UID[6]; 28 char GID[6]; 29 char AccessMode[8]; 30 char Size[10]; //< Size of data, not including header or padding. 31 char Terminator[2]; 32 33 ///! Get the name without looking up long names. 34 StringRef getName() const { 35 char EndCond = Name[0] == '/' ? ' ' : '/'; 36 StringRef::size_type end = StringRef(Name, sizeof(Name)).find(EndCond); 37 if (end == StringRef::npos) 38 end = sizeof(Name); 39 assert(end <= sizeof(Name) && end > 0); 40 // Don't include the EndCond if there is one. 41 return StringRef(Name, end); 42 } 43 44 uint64_t getSize() const { 45 APInt ret; 46 StringRef(Size, sizeof(Size)).getAsInteger(10, ret); 47 return ret.getZExtValue(); 48 } 49 }; 50 51 const ArchiveMemberHeader *ToHeader(const char *base) { 52 return reinterpret_cast<const ArchiveMemberHeader *>(base); 53 } 54 } 55 56 Archive::Child Archive::Child::getNext() const { 57 size_t SpaceToSkip = sizeof(ArchiveMemberHeader) + 58 ToHeader(Data.data())->getSize(); 59 // If it's odd, add 1 to make it even. 60 if (SpaceToSkip & 1) 61 ++SpaceToSkip; 62 63 const char *NextLoc = Data.data() + SpaceToSkip; 64 65 // Check to see if this is past the end of the archive. 66 if (NextLoc >= Parent->Data->getBufferEnd()) 67 return Child(Parent, StringRef(0, 0)); 68 69 size_t NextSize = sizeof(ArchiveMemberHeader) + 70 ToHeader(NextLoc)->getSize(); 71 72 return Child(Parent, StringRef(NextLoc, NextSize)); 73 } 74 75 error_code Archive::Child::getName(StringRef &Result) const { 76 StringRef name = ToHeader(Data.data())->getName(); 77 // Check if it's a special name. 78 if (name[0] == '/') { 79 if (name.size() == 1) { // Linker member. 80 Result = name; 81 return object_error::success; 82 } 83 if (name.size() == 2 && name[1] == '/') { // String table. 84 Result = name; 85 return object_error::success; 86 } 87 // It's a long name. 88 // Get the offset. 89 APInt offset; 90 name.substr(1).getAsInteger(10, offset); 91 const char *addr = Parent->StringTable->Data.begin() 92 + sizeof(ArchiveMemberHeader) 93 + offset.getZExtValue(); 94 // Verify it. 95 if (Parent->StringTable == Parent->end_children() 96 || addr < (Parent->StringTable->Data.begin() 97 + sizeof(ArchiveMemberHeader)) 98 || addr > (Parent->StringTable->Data.begin() 99 + sizeof(ArchiveMemberHeader) 100 + Parent->StringTable->getSize())) 101 return object_error::parse_failed; 102 Result = addr; 103 return object_error::success; 104 } 105 // It's a simple name. 106 if (name[name.size() - 1] == '/') 107 Result = name.substr(0, name.size() - 1); 108 else 109 Result = name; 110 return object_error::success; 111 } 112 113 uint64_t Archive::Child::getSize() const { 114 return ToHeader(Data.data())->getSize(); 115 } 116 117 MemoryBuffer *Archive::Child::getBuffer() const { 118 StringRef name; 119 if (getName(name)) return NULL; 120 return MemoryBuffer::getMemBuffer(Data.substr(sizeof(ArchiveMemberHeader), 121 getSize()), 122 name, 123 false); 124 } 125 126 error_code Archive::Child::getAsBinary(OwningPtr<Binary> &Result) const { 127 OwningPtr<Binary> ret; 128 if (error_code ec = 129 createBinary(getBuffer(), ret)) 130 return ec; 131 Result.swap(ret); 132 return object_error::success; 133 } 134 135 Archive::Archive(MemoryBuffer *source, error_code &ec) 136 : Binary(Binary::isArchive, source) 137 , StringTable(Child(this, StringRef(0, 0))) { 138 // Check for sufficient magic. 139 if (!source || source->getBufferSize() 140 < (8 + sizeof(ArchiveMemberHeader) + 2) // Smallest archive. 141 || StringRef(source->getBufferStart(), 8) != Magic) { 142 ec = object_error::invalid_file_type; 143 return; 144 } 145 146 // Get the string table. It's the 3rd member. 147 child_iterator StrTable = begin_children(); 148 child_iterator e = end_children(); 149 for (int i = 0; StrTable != e && i < 2; ++StrTable, ++i) {} 150 151 // Check to see if there were 3 members, or the 3rd member wasn't named "//". 152 StringRef name; 153 if (StrTable != e && !StrTable->getName(name) && name == "//") 154 StringTable = StrTable; 155 156 ec = object_error::success; 157 } 158 159 Archive::child_iterator Archive::begin_children() const { 160 const char *Loc = Data->getBufferStart() + Magic.size(); 161 size_t Size = sizeof(ArchiveMemberHeader) + 162 ToHeader(Loc)->getSize(); 163 return Child(this, StringRef(Loc, Size)); 164 } 165 166 Archive::child_iterator Archive::end_children() const { 167 return Child(this, StringRef(0, 0)); 168 } 169 170 namespace llvm { 171 172 } // end namespace llvm 173