apt-inst/contrib/arfile.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: arfile.cc,v 1.3 2002/09/20 04:42:25 tausq Exp $
   4 /* ######################################################################
   5
   6    AR File - Handle an 'AR' archive
   7
   8    AR Archives have plain text headers at the start of each file
   9    section. The headers are aligned on a 2 byte boundry.
  10
  11    Information about the structure of AR files can be found in ar(5)
  12    on a BSD system, or in the binutils source.
  13
  14    ##################################################################### */
  15                                                                         /*}}}*/
  16 // Include Files                                                        /*{{{*/
  17 #ifdef __GNUG__
  18 #pragma implementation "apt-pkg/arfile.h"
  19 #endif
  20 #include <apt-pkg/arfile.h>
  21 #include <apt-pkg/strutl.h>
  22 #include <apt-pkg/error.h>
  23
  24 #include <stdlib.h>
  25                                                                         /*}}}*/
  26
  27 struct ARArchive::MemberHeader
  28 {
  29    char Name[16];
  30    char MTime[12];
  31    char UID[6];
  32    char GID[6];
  33    char Mode[8];
  34    char Size[10];
  35    char Magic[2];
  36 };
  37
  38 // ARArchive::ARArchive - Constructor                                   /*{{{*/
  39 // ---------------------------------------------------------------------
  40 /* */
  41 ARArchive::ARArchive(FileFd &File) : List(0), File(File)
  42 {
  43    LoadHeaders();
  44 }
  45                                                                         /*}}}*/
  46 // ARArchive::~ARArchive - Destructor                                   /*{{{*/
  47 // ---------------------------------------------------------------------
  48 /* */
  49 ARArchive::~ARArchive()
  50 {
  51    while (List != 0)
  52    {
  53       Member *Tmp = List;
  54       List = List->Next;
  55       delete Tmp;
  56    }
  57 }
  58                                                                         /*}}}*/
  59 // ARArchive::LoadHeaders - Load the headers from each file             /*{{{*/
  60 // ---------------------------------------------------------------------
  61 /* AR files are structured with a 8 byte magic string followed by a 60
  62    byte plain text header then the file data, another header, data, etc */
  63 bool ARArchive::LoadHeaders()
  64 {
  65    signed long Left = File.Size();
  66
  67    // Check the magic byte
  68    char Magic[8];
  69    if (File.Read(Magic,sizeof(Magic)) == false)
  70       return false;
  71    if (memcmp(Magic,"!<arch>\012",sizeof(Magic)) != 0)
  72       return _error->Error("Invalid archive signature");
  73    Left -= sizeof(Magic);
  74
  75    // Read the member list
  76    while (Left > 0)
  77    {
  78       MemberHeader Head;
  79       if (File.Read(&Head,sizeof(Head)) == false)
  80          return _error->Error("Error reading archive member header");
  81       Left -= sizeof(Head);
  82
  83       // Convert all of the integer members
  84       Member *Memb = new Member();
  85       if (StrToNum(Head.MTime,Memb->MTime,sizeof(Head.MTime)) == false ||
  86           StrToNum(Head.UID,Memb->UID,sizeof(Head.UID)) == false ||
  87           StrToNum(Head.GID,Memb->GID,sizeof(Head.GID)) == false ||
  88           StrToNum(Head.Mode,Memb->Mode,sizeof(Head.Mode),8) == false ||
  89           StrToNum(Head.Size,Memb->Size,sizeof(Head.Size)) == false)
  90       {
  91          delete Memb;
  92          return _error->Error("Invalid archive member header");
  93       }
  94
  95       // Check for an extra long name string
  96       if (memcmp(Head.Name,"#1/",3) == 0)
  97       {
  98          char S[300];
  99          unsigned long Len;
 100          if (StrToNum(Head.Name+3,Len,sizeof(Head.Size)-3) == false ||
 101              Len >= strlen(S))
 102          {
 103             delete Memb;
 104             return _error->Error("Invalid archive member header");
 105          }
 106          if (File.Read(S,Len) == false)
 107             return false;
 108          S[Len] = 0;
 109          Memb->Name = S;
 110          Memb->Size -= Len;
 111          Left -= Len;
 112       }
 113       else
 114       {
 115          unsigned int I = sizeof(Head.Name) - 1;
 116          for (; Head.Name[I] == ' ' || Head.Name[I] == '/'; I--);
 117          Memb->Name = string(Head.Name,0,I+1);
 118       }
 119
 120       // Account for the AR header alignment
 121       unsigned Skip = Memb->Size % 2;
 122
 123       // Add it to the list
 124       Memb->Next = List;
 125       List = Memb;
 126       Memb->Start = File.Tell();
 127       if (File.Skip(Memb->Size + Skip) == false)
 128          return false;
 129       if (Left < (signed)(Memb->Size + Skip))
 130          return _error->Error("Archive is too short");
 131       Left -= Memb->Size + Skip;
 132    }
 133    if (Left != 0)
 134       return _error->Error("Failed to read the archive headers");
 135
 136    return true;
 137 }
 138                                                                         /*}}}*/
 139 // ARArchive::FindMember - Find a name in the member list               /*{{{*/
 140 // ---------------------------------------------------------------------
 141 /* Find a member with the given name */
 142 const ARArchive::Member *ARArchive::FindMember(const char *Name) const
 143 {
 144    const Member *Res = List;
 145    while (Res != 0)
 146    {
 147       if (Res->Name == Name)
 148          return Res;
 149       Res = Res->Next;
 150    }
 151
 152    return 0;
 153 }
 154                                                                         /*}}}*/